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Glossary of genetics (M–Z) O Glossary_of_genetics_(M–Z) > O operon A functional unit of gene expression consisting of a cluster of adjacent structural genes which are collectively under the control of a single promoter, along with one or more adjacent regulatory sequences such as operators which affect transcription of the structural genes. The set of genes is transcribed together, usually resulting in a single polycistronic messenger RNA molecule, which may then be translated together or undergo splicing to create multiple mRNAs which are translated independently; the result is that the genes contained in the operon are either expressed together or not at all. Regulatory proteins, including repressors, corepressors, and activators, usually bind specifically to the regulatory sequences of a given operon; by some definitions, the genes that code for these regulatory proteins are also considered part of the operon. |
Peripheral tolerance Tolerogenic DCs Peripheral_tolerance > Cells mediating peripheral tolerance > Tolerogenic DCs DCs are a major cell population responsible for the initiation of the adaptive immune response. They present short peptides on MHCII, which are recognized by specific TCR. After encountering an antigen with recognition danger or pathogen-associated molecular patterns, DCs start the secretion of proinflammatory cytokines, express costimulatory molecules CD80 and CD86 and migrate to the lymph nodes to activate naive T cells. However, immature DCs (iDCs) are able to induce both CD4 and CD8 tolerance. |
Exon junction complex Mechanism Exon_junction_complex > Mechanism In order for the translocation of mRNAs through the nuclear pore complex to occur, a heterodimer consisting of NXF1/TAP and NXT1/p15 must bind to the transcripts. NXF1/TAP is a major receptor for the export of mRNAs to the cytoplasm. This is because it interacts with both RNA-binding adapter proteins and components of the nuclear pore complex.Recognition of a premature termination codon occurs during translation in the cytoplasm. The image shown below implies that this event is nuclear, contrary to the general view in this field. Readers should be aware that translation in the nucleus is a highly controversial subject that is not well-supported by data. |
Newton's cradle Simple solution Newton's_cradle > Physics explanation > Simple solution The simple effect from two same-mass efficiently elastic colliding objects constrained to a straight path is the basis of the effect seen in the cradle and gives an approximate solution to all its activities. For a sequence of same-mass elastic objects constrained to a straight path, the effect continues to each successive object. For example, when two balls are dropped to strike three stationary balls in a cradle, there is an unnoticed but crucial small distance between the two dropped balls, and the action is as follows: the first moving ball that strikes the first stationary ball (the second ball striking the third ball) transfers all of its momentum to the third ball and stops. |
Mir-16 microRNA precursor family Clinical relevance Mir-16_microRNA_precursor_family > Clinical relevance Altered expression of microRNA-16 has been observed in cancer, including malignancies of the breast, colon, brain , lung, lymphatic system, ovaries, pancreas , prostate and stomach. This difference in expression levels can be used distinguish between cancerous and healthy tissues and to determine clinical prognosis. The fact that pathology is associated with a different expression profile has led to the proposal that disease specific biomarkers can provide potential targets for directed clinical intervention. More recently, there is evidence that in colorectal cancer that the efficacy of treatment with the monoclonal antibody cetuximab can be assessed by the expression pattern of colorectal carcinoma after therapy.miR-16 and miR-15a are clustered within a 0.5 kbp region in Chromosome 13 (13q14) in humans, a chromosomal region shown to be deleted or down-regulated in approximately more than half of B-CLL, the most prevalent form of leukemia in adults. Carcinogenesis is a gradual process, involving multiple genetic mutations, thus every patient with malignancy presents with a heterogeneous population of cells. The fact that mir-16 microRNA loss is observed in a large proportion of cells indicates the change occurred early in cancer development and a target for therapeutic intervention. |
Pyridoxine deficiency Absorption, metabolism and excretion Vitamin_B6 > Absorption, metabolism and excretion The PLP-albumin complex is what is released by the liver to circulate in plasma. Protein-binding capacity is the limiting factor for vitamin storage. Total body stores, the majority in muscle, with a lesser amount in liver, have been estimated to be in the range of 61 to 167 mg.Enzymatic processes utilize PLP as a phosphate-donating cofactor. |
Madelung equations Derivation Madelung_equations > Derivation The Madelung equations are derived by writing the wavefunction in polar form: and substituting this form into the Schrödinger equation The flow velocity is defined by from which we also find that where j {\displaystyle \mathbf {j} } is the probability current of standard quantum mechanics. The quantum force, which is the negative of the gradient of the quantum potential, can also be written in terms of the quantum pressure tensor: where The integral energy stored in the quantum pressure tensor is proportional to the Fisher information, which accounts for the quality of measurements. Thus, according to the Cramér–Rao bound, the Heisenberg uncertainty principle is equivalent to a standard inequality for the efficiency of measurements. The thermodynamic definition of the quantum chemical potential follows from the hydrostatic force balance above: According to thermodynamics, at equilibrium the chemical potential is constant everywhere, which corresponds straightforwardly to the stationary Schrödinger equation. |
Block swap algorithms Reversal algorithm Block_swap_algorithms > Reversal algorithm The reversal algorithm is the simplest to explain, using rotations. A rotation is an in-place reversal of array elements. This method swaps two elements of an array from outside in within a range. The rotation works for an even or odd number of array elements. |
Negishi coupling Reaction mechanism Negishi_coupling > Reaction mechanism In one Negishi model system the formation of homocoupling was found to be the result of a second transmetalation reaction between the diarylmetal intermediate and arylmetal halide: Ar–Pd–Ar' + Ar'–Zn–X → Ar'–Pd–Ar' + Ar–Zn–X Ar'–Pd–Ar' → Ar'–Ar' + Pd(0) (homocoupling) Ar–Zn–X + H2O → Ar–H + HO–Zn–X (reaction accompanied by dehalogenation) Nickel catalyzed systems can operate under different mechanisms depending on the coupling partners. Unlike palladium systems which involve only Pd0 or PdII, nickel catalyzed systems can involve nickel of different oxidation states. Both systems are similar in that they involve similar elementary steps: oxidative addition, transmetalation, and reductive elimination. |
Relative velocity time dilation Simple inference Relative_velocity_time_dilation > Time dilation caused by a relative velocity > Simple inference The separation of the mirrors is L and the clock ticks once each time the light pulse hits mirror A. In the frame in which the clock is at rest (see left part of the diagram), the light pulse traces out a path of length 2L and the period of the clock is 2L divided by the speed of light: Δ t = 2 L c {\displaystyle \Delta t={\frac {2L}{c}}} From the frame of reference of a moving observer traveling at the speed v relative to the resting frame of the clock (right part of diagram), the light pulse is seen as tracing out a longer, angled path. Keeping the speed of light constant for all inertial observers requires a lengthening of the period of this clock from the moving observer's perspective. That is to say, as measured in a frame moving relative to the local clock, this clock will be running more slowly. Straightforward application of the Pythagorean theorem leads to the well-known prediction of special relativity: The total time for the light pulse to trace its path is given by: Δ t ′ = 2 D c {\displaystyle \Delta t'={\frac {2D}{c}}} The length of the half path can be calculated as a function of known quantities as: D = ( 1 2 v Δ t ′ ) 2 + L 2 {\displaystyle D={\sqrt {\left({\frac {1}{2}}v\Delta t'\right)^{2}+L^{2}}}} Elimination of the variables D and L from these three equations results in: Δ t ′ = Δ t 1 − v 2 c 2 {\displaystyle \Delta t'={\frac {\Delta t}{\sqrt {1-{\frac {v^{2}}{c^{2}}}}}}} which expresses the fact that the moving observer's period of the clock Δ t ′ {\displaystyle \Delta t'} is longer than the period Δ t {\displaystyle \Delta t} in the frame of the clock itself. Because all clocks that have a common period in the resting frame should have a common period when observed from the moving frame, all other clocks—mechanical, electronic, optical (such as an identical horizontal version of the clock in the example)—should exhibit the same velocity-dependent time dilation. |
Organic life DNA Organic_life > Environmental conditions > Chemical elements > DNA Under the genetic code, RNA strands are translated to specify the sequence of amino acids within proteins. These RNA strands are initially created using DNA strands as a template in a process called transcription. Within cells, DNA is organised into long structures called chromosomes. |
Boolean rings Summary Boolean_ring In mathematics, a Boolean ring R is a ring for which x2 = x for all x in R, that is, a ring that consists only of idempotent elements. An example is the ring of integers modulo 2. Every Boolean ring gives rise to a Boolean algebra, with ring multiplication corresponding to conjunction or meet ∧, and ring addition to exclusive disjunction or symmetric difference (not disjunction ∨, which would constitute a semiring). Conversely, every Boolean algebra gives rise to a Boolean ring. Boolean rings are named after the founder of Boolean algebra, George Boole. |
Simultaneously triangularizable Triangularisability Back_substitution > Triangularisability A more precise statement is given by the Jordan normal form theorem, which states that in this situation, A is similar to an upper triangular matrix of a very particular form. The simpler triangularization result is often sufficient however, and in any case used in proving the Jordan normal form theorem.In the case of complex matrices, it is possible to say more about triangularization, namely, that any square matrix A has a Schur decomposition. This means that A is unitarily equivalent (i.e. similar, using a unitary matrix as change of basis) to an upper triangular matrix; this follows by taking an Hermitian basis for the flag. |
Lactobacillus vaccine Humoral immune response Lactobacillus_vaccine > Mechanism of action > Humoral immune response The agglutination titres were determined by preparing two-fold serial dilutions of the serum samples in isotonic saline (dilutions of 1:10 to 1:1280), using 0.5 ml concentrated lactobacillus vaccine as an agglutinogen. An at least threefold elevation of the agglutination titres following primary immunization was detected in the serum of 93.8% of patients; the rest of the patients were considered non-responders or poor responders to the vaccination. The geometric mean of the agglutination titres increased from the basal level of 1:56 before vaccination to 1:320 after finishing the primary immunization program, and it was still 1:140 one year later. |
Autonomous agency theory Development Autonomous_agency_theory > Development This is normally used to model plural situations like organisations or a nation states, when its personality system is taken to have normative characteristics (see also Normative personality), that is, driven by cultural norms as represented in Figure 2 below. This has developed further through mindset agency theory enabling agency behaviour to be anticipated. A feature of this modelling approach is that the properties of the cultural system act as an attractor for the agency as a whole, providing constraint for the properties of its personality and operative systems. This attraction ceases with cultural instability, when CAT reduces to instrumentality with no capacity to learn. Another feature is driven by possibilities of recursion permitted using Beer's proposition of viability law: every viable system contains and is contained in a viable system. |
Cellular evolution Community metabolism Cell_evolution > Community metabolism The archean prokaryote cell concept is often termed as the endosymbiotic theory. There is still debate about whether organelles like the hydrogenosome predated the origin of mitochondria, or vice versa: see the hydrogen hypothesis for the origin of eukaryotic cells. How the current lineages of microbes evolved from this postulated community is currently unsolved, but subject to intense research by biologists, stimulated by the great flow of new discoveries in genome science. |
Adrenal insufficiency Cortisol deficiency Adrenocortical_insufficiency > Pathophysiology > Cortisol deficiency Cortisol increases blood sugar by inducing gluconeogenesis (glucose production) in the liver, lipolysis (fat breakdown) in adipose tissue, and proteolysis (muscle breakdown) in muscle while increasing glucagon secretion and decreasing insulin secretion in the pancreas. Overall, these actions cause the body to use fat stores and muscle for energy. Deficiency results in hypoglycemia, with associated nausea, vomiting, fatigue, and weakness.Cortisol potentiates the effectiveness of angiotensin II and catecholamines such as norepinephrine in vasoconstriction. |
Riemann integration Similar concepts Riemann_integrability > Similar concepts However, combining these restrictions, so that one uses only left-hand or right-hand Riemann sums on regularly divided intervals, is dangerous. If a function is known in advance to be Riemann integrable, then this technique will give the correct value of the integral. But under these conditions the indicator function I Q {\displaystyle I_{\mathbb {Q} }} will appear to be integrable on with integral equal to one: Every endpoint of every subinterval will be a rational number, so the function will always be evaluated at rational numbers, and hence it will appear to always equal one. |
Heater core Control Heater_core > Control Simpler systems allow the driver to control the valve or door directly (usually by means of a rotary knob, or a lever). More complicated systems use a combination of electromechanical actuators and thermistors to control the valve or doors to deliver air at a precise temperature value selected by the user. Cars with dual climate function (allowing driver and passenger to each set a different temperature) may use a heater core split in two, where different amounts of coolant flow through the heater core on either side to obtain the desired heating. |
H3R17me2 Epigenetic implications H3T45P > Epigenetic implications The post-translational modification of histone tails by either histone-modifying complexes or chromatin remodeling complexes is interpreted by the cell and leads to complex, combinatorial transcriptional output. It is thought that a histone code dictates the expression of genes by a complex interaction between the histones in a particular region. The current understanding and interpretation of histones comes from two large scale projects: ENCODE and the Epigenomic roadmap. The purpose of the epigenomic study was to investigate epigenetic changes across the entire genome. |
IABG Aeronautics IABG > Business areas > Aeronautics The company tests aircraft and individual assemblies for their strength and durability. This includes life and safety analyses, test concepts and programs, test simulation, static load tests, operational strength tests on entire skin and substructures, material testing and nondestructive testing. Important projects are the structural fatigue test on the Airbus A380 (finished 2012), the fatigue test on the overall structure of the A400M military transport, the life extension tests on the A320 as well as the structural fatigue tests on the A350 XWB. |
Microbial symbiosis and immunity Regulation of immune responses Microbial_symbiosis_and_immunity > Gastrointestinal tract > Regulation of immune responses Maturation of the GI tract is mediated by pattern recognition receptors (PRRs), which recognize non-self pathogen associated molecular patterns (PAMPs) including bacterial cell wall components and nucleic acids. These data suggest that commensal microbes aid in intestinal homeostasis and immune system development.To prevent constant activation of immune cells and resulting inflammation, hosts and bacteria have evolved to maintain intestinal homeostasis and immune system development. For example, the human symbiont Bacteroides fragilis produces polysaccharide A (PSA), which binds to toll-like receptor 2 (TLR-2) on CD4+ T cells. |
Point-of-care ultrasound Resuscitation of the critically ill Point-of-care_ultrasound > Scope > Resuscitation of the critically ill People presenting with hypotension of unknown cause, ultrasound has been utilized to determine the cause of shock. Evaluation of the heart and inferior vena cava (IVC) can help the clinician at the bedside choose important treatments and monitor the response to the interventions.A person who has hypotension and a bedside ultrasound showing hyperdynamic left heart with a flat, collapsible IVC indicates low blood volume. If the person also has a fever, the clinician may determine sepsis, or severe infection is causing the problem. |
Enteric nervous system Neurogastroenterology societies Enteric_nervous_system > Neurogastroenterology societies American Neurogastroenterology and Motility Society European Society of Neurogastroenterology and MotilityNeurogastroenterology & Motility |
Epoxyeicosatrienoic acids Inflammation Epoxyeicosatrienoic_acid > Clinical significance > Inflammation In vitro and animal model studies indicate that the EETs possess anti-inflammatory activity that is directed toward reducing, resolving, and limiting the damage caused by inflammation. Most of these studies have focused on circulating leukocytes, blood vessel endothelium, and the occlusion of blood vessels due to pathological blood clotting. EETs a) inhibit vascular endothelial cells from expressing Cell adhesion molecules such as VCAM-1, ICAM-1, and E-selectin thereby limiting circulating leukocytes from adhering to blood vessel endothelium and migrating across this endothelium into tissues; 2) inhibit the expression and activity of cyclooxygenase-2 in blood monocytes thereby reducing their production of pro-inflammatory metabolites of arachidonic acid such as prostaglandin E2; 3) inhibit platelet aggregation thereby reducing thrombus (i.e. blood clot) formation; 4) promote fibrinolysis thereby dissolving blood clots; and 5) inhibit vascular smooth muscle cell proliferation thereby reducing blood vessel hypertrophy and narrowing. |
Intravitreal injection Antibiotics Intravitreal_injection > Common medications used in injection > Antimicrobials > Antibiotics This type of drug targets on bacterial infection. The first use of intravitreal antibiotics was dated back to experiments in the 1940s, in which penicillin and sulfonamides were used to treat the rabbit endophthalmitis models. Later, more studies proved the beneficial effects of intravitreal antibiotics on acute postoperative endophthalmitis. In the 1970s, Peyman’s research on the suggested doses for the medications was published. |
Comparison of vector algebra and geometric algebra Matrix Related Comparison_of_vector_algebra_and_geometric_algebra > Translations between formalisms > Matrix Related When the wedge product is coupled with the Clifford product and put into a natural geometric context, the fact that the determinants are used in the expression of R N {\displaystyle {\mathbb {R} }^{N}} parallelogram area and parallelepiped volumes (and higher-dimensional generalizations thereof) also comes as a nice side-effect. As is also shown below, results such as Cramer's rule also follow directly from the wedge product's selection of non-identical elements. |
Freiling's axiom of symmetry Objections to Freiling's argument Freiling's_axiom_of_symmetry > Objections to Freiling's argument A minor variation of his argument gives a contradiction with the axiom of choice whether or not one accepts the continuum hypothesis, if one replaces countable additivity of probability by additivity for cardinals less than the continuum. (Freiling used a similar argument to claim that Martin's axiom is false.) It is not clear why Freiling's intuition should be any less applicable in this instance, if it applies at all. (Maddy 1988, p. 500) So Freiling's argument seems to be more an argument against the possibility of well ordering the reals than against the continuum hypothesis. |
Search engine optimization copywriting Relationship with Google Search-engine_optimization > History > Relationship with Google Patents related to search engines can provide information to better understand search engines. In 2005, Google began personalizing search results for each user. Depending on their history of previous searches, Google crafted results for logged in users.In 2007, Google announced a campaign against paid links that transfer PageRank. |
CAD/CAM dentistry History CAD/CAM_dentistry > History Although CAD/CAM dentistry was used in the mid-1980s, early efforts were considered a cumbersome novelty, requiring an inordinate amount of time to produce a viable product. This inefficiency prevented its use within dental offices and limited it to labside use (that is, used within dental laboratories). As adjunctive techniques, software, and materials improved, the chairside use of CAD/CAM (use within dental offices/surgeries) increased. For example, the commercialization of Cerec by Sirona made CAD/CAM available to dentists who formerly would not have had avenues for using it. |
Daria Hazuda Research on HIV-1 integrase inhibitors Daria_Hazuda > Career and research > Research on HIV-1 integrase inhibitors As a retrovirus, HIV has an RNA genome which it reverse transcribes into a double-stranded DNA copy, which it then inserts into the host cell's genome. This insertion is done by an enzyme called integrase which has several sequential functions: it binds to the ends of the viral DNA and processes them by removing a couple of nucleotides from each end. It then aids the 3'OH of the viral DNA in attacking the phosphodiester backbone of the host DNA, cleaving it at an integration site and attaching the viral DNA in a step called strand transfer. Cellular enzymes then fill in the gaps.Hazuda was not the first or only scientist working to develop integrase inhibitors. |
Bayesian models Summary Bayesian_models Bayesian statistics ( BAY-zee-ən or BAY-zhən) is a theory in the field of statistics based on the Bayesian interpretation of probability where probability expresses a degree of belief in an event. The degree of belief may be based on prior knowledge about the event, such as the results of previous experiments, or on personal beliefs about the event. This differs from a number of other interpretations of probability, such as the frequentist interpretation that views probability as the limit of the relative frequency of an event after many trials.Bayesian statistical methods use Bayes' theorem to compute and update probabilities after obtaining new data. Bayes' theorem describes the conditional probability of an event based on data as well as prior information or beliefs about the event or conditions related to the event. |
Osmoregulation In plants Osmoregulation > In plants Other plants have leaf modifications to reduce water loss, such as needle-shaped leaves, sunken stomata, and thick, waxy cuticles as in the pine. The sand-dune marram grass has rolled leaves with stomata on the inner surface. Hydrophytes are plants that grow in aquatic habitats; they may be floating, submerged, or emergent, and may grow in seasonal (rather than permanent) wetlands. |
Programmable Universal Machine for Assembly Summary Programmable_Universal_Machine_for_Assembly The operating system is loaded from external storage through a serial port, usually from a floppy disk. The control unit also contains the servo power supply, analog and digital feedback processing boards, and servo drive system. The arm appears in the film Innerspace. An arm was displayed in the "Bird And The Robot" attraction at the World of Motion pavilion of EPCOT. |
Space (mathematics) Spaces and structure Mathematical_space > Spaces and structure Clearly, groups are algebraic, while Euclidean spaces are geometric. Modules over rings are as algebraic as groups. In particular, when the ring appears to be a field, the module appears to be a linear space; is it algebraic or geometric? |
MO diagram Diatomic MO diagrams Molecular_orbital_diagram > Diatomic MO diagrams A diatomic molecular orbital diagram is used to understand the bonding of a diatomic molecule. MO diagrams can be used to deduce magnetic properties of a molecule and how they change with ionization. They also give insight to the bond order of the molecule, how many bonds are shared between the two atoms.The energies of the electrons are further understood by applying the Schrödinger equation to a molecule. Quantum Mechanics is able to describe the energies exactly for single electron systems but can be approximated precisely for multiple electron systems using the Born-Oppenheimer Approximation, such that the nuclei are assumed stationary. |
Prime divisor Definition and examples Prime_factor > Definition and examples This leads to an equivalent definition of prime numbers: they are the numbers with exactly two positive divisors. Those two are 1 and the number itself. As 1 has only one divisor, itself, it is not prime by this definition. |
Nonrenormalization theorems Summary Nonrenormalization_theorem In theoretical physics a nonrenormalization theorem is a limitation on how a certain quantity in the classical description of a quantum field theory may be modified by renormalization in the full quantum theory. Renormalization theorems are common in theories with a sufficient amount of supersymmetry, usually at least 4 supercharges. Perhaps the first nonrenormalization theorem was introduced by Marcus T. Grisaru, Martin Rocek and Warren Siegel in their 1979 paper Improved methods for supergraphs. |
Analytic–synthetic distinction Kant's version and the a priori–a posteriori distinction Analytic–synthetic_distinction > Kant > Kant's version and the a priori–a posteriori distinction In the Introduction to the Critique of Pure Reason, Kant contrasts his distinction between analytic and synthetic propositions with another distinction, the distinction between a priori and a posteriori propositions. He defines these terms as follows: a priori proposition: a proposition whose justification does not rely upon experience. Moreover, the proposition can be validated by experience, but is not grounded in experience. Therefore, it is logically necessary. |
Absolute Zero Limit to the "degree of cold" Zero_temperature > History > Limit to the "degree of cold" The question whether there is a limit to the degree of coldness possible, and, if so, where the zero must be placed, was first addressed by the French physicist Guillaume Amontons in 1702, in connection with his improvements in the air thermometer. His instrument indicated temperatures by the height at which a certain mass of air sustained a column of mercury—the volume, or "spring" of the air varying with temperature. Amontons therefore argued that the zero of his thermometer would be that temperature at which the spring of the air was reduced to nothing. He used a scale that marked the boiling point of water at +73 and the melting point of ice at +51+1⁄2, so that the zero was equivalent to about −240 on the Celsius scale. |
Mathematical sociology History Mathematical_sociology > History Through formalization by mathematician Frank Harary, this work produced the fundamental theorem of this theory. It says that if a network of interrelated positive and negative ties is balanced, e.g. as illustrated by the psychological principle that "my friend's enemy is my enemy", then it consists of two sub-networks such that each has positive ties among its nodes and there are only negative ties between nodes in distinct sub-networks. The imagery here is of a social system that splits into two cliques. |
DNS blocking Summary DNS_blocking DNS blocking can be applied to individual servers/IP address, or entire blocks of IP addresses for multiple reasons. Some public DNS Resolvers, like Quad9 and CleanBrowsing offer filters are part of their DNS. Quad9, for example, blocks access to known phishing and malicious domains. CleanBrowsing filters out adult content in their effort to protect kids online. |
Spring tides Current Ebb_tide > Observation and prediction > Current Also, although a water channel's center is the most useful measuring site, mariners object when current-measuring equipment obstructs waterways. A flow proceeding up a curved channel may have similar magnitude, even though its direction varies continuously along the channel. Surprisingly, flood and ebb flows are often not in opposite directions. |
Press fitting Summary Press_fitting An interference fit, also known as a pressed fit or friction fit, is a form of fastening between two tightfitting mating parts that produces a joint which is held together by friction after the parts are pushed together.Depending on the amount of interference, parts may be joined using a tap from a hammer or pressed together using a hydraulic ram. Critical components that must not sustain damage during joining may also be cooled significantly below room temperature to shrink one of the components before fitting. This method allows the components to be joined without force and produces a shrink fit interference when the component returns to normal temperature. |
Electromagnetic emission Derivation from electromagnetic theory Electromagnetic_signal > Derivation from electromagnetic theory The electric field, magnetic field, and direction of wave propagation are all orthogonal, and the wave propagates in the same direction as E × B {\displaystyle \mathbf {E} \times \mathbf {B} } . Also, E and B far-fields in free space, which as wave solutions depend primarily on these two Maxwell equations, are in-phase with each other. This is guaranteed since the generic wave solution is first order in both space and time, and the curl operator on one side of these equations results in first-order spatial derivatives of the wave solution, while the time-derivative on the other side of the equations, which gives the other field, is first-order in time, resulting in the same phase shift for both fields in each mathematical operation. |
Reducible polynomial Algorithms Reducible_polynomial > Algorithms The unique factorization property of polynomials does not mean that the factorization of a given polynomial may always be computed. Even the irreducibility of a polynomial may not always be proved by a computation: there are fields over which no algorithm can exist for deciding the irreducibility of arbitrary polynomials.Algorithms for factoring polynomials and deciding irreducibility are known and implemented in computer algebra systems for polynomials over the integers, the rational numbers, finite fields and finitely generated field extension of these fields. All these algorithms use the algorithms for factorization of polynomials over finite fields. |
Linear time-invariant system Z and discrete-time Fourier transforms Linear_time-invariant_system > Discrete-time systems > Z and discrete-time Fourier transforms The discrete-time Fourier transform Fourier series may be used for analyzing periodic signals. Due to the convolution property of both of these transforms, the convolution that gives the output of the system can be transformed to a multiplication in the transform domain. That is, Just as with the Laplace transform transfer function in continuous-time system analysis, the Z transform makes it easier to analyze systems and gain insight into their behavior. |
Folk physics Solidity Folk_physics > Psychological research > Types of experiments > Solidity An experiment that tests an infant's knowledge of solidity involves the impossible event of one solid object passing through another. First, the infant is shown a flat, solid square moving from 0° to 180° in an arch formation. Next, a solid block is placed in the path of the screen, preventing it from completing its full range of motion. The infant habituates to this event, as it is what anyone would expect. Then, the experimenter creates the impossible event, and the solid screen passes through the solid block. The infant is confused by the event and attends longer than in probable event trial. |
Magnetic tension Summary Magnetic_tension In physics, magnetic tension is a restoring force with units of force density that acts to straighten bent magnetic field lines. In SI units, the force density f T {\displaystyle \mathbf {f} _{T}} exerted perpendicular to a magnetic field B {\displaystyle \mathbf {B} } can be expressed as f T = ( B ⋅ ∇ ) B μ 0 {\displaystyle \mathbf {f} _{T}={\frac {\left(\mathbf {B} \cdot \nabla \right)\mathbf {B} }{\mu _{0}}}} where μ 0 {\displaystyle \mu _{0}} is the vacuum permeability. Magnetic tension forces also rely on vector current densities and their interaction with the magnetic field. Plotting magnetic tension along adjacent field lines can give a picture as to their divergence and convergence with respect to each other as well as current densities.Magnetic tension is analogous to the restoring force of rubber bands. |
Formalized mathematics Summary Formalized_mathematics It is not the primary aim of this article to say anything about the relative merits of these theories as foundations for mathematics. The reason for the use of two different set theories is to illustrate that multiple approaches to the implementation of mathematics are feasible. Precisely because of this approach, this article is not a source of "official" definitions for any mathematical concept. |
Continuum robot Advantages Continuum_robot > Advantages The particular design of continuum robots offers several advantages with respect to rigid-link robots. First of all, as already said, continuum robots can more easily operate in environments that require a high level of dexterity, adaptability and flexibility. Moreover, the simplicity of their structure makes continuum robots more prone to miniaturisation. |
Mir-625 microRNA precursor family Summary Mir-625_microRNA_precursor_family In molecular biology mir-625 microRNA is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms. Many microRNAs play important roles in cancer development and progression. |
Soy protein Biological value Soy_protein > Nutrition > Biological value Another measure of a protein's use in nutrition is the biological value scale, which dates back to 1911; it relies on nitrogen retention as a measurement of protein quality. Soybean protein isolate has a biological value of 74. Whole soybean has a biological value of 96, and soy milk 91. |
Hydrogen bond catalysis Challenges and future goals Hydrogen_bond_catalysis > Challenges and future goals Ideally, rational catalyst design will eventually replace screening of families of catalysts and the choice of building blocks will become more systematic. Scope: While new reactions are constantly being discovered, most reactions have extremely narrow substrate scope and the reason for such narrow scope is often not understood. In the field of palladium catalysis, after the foundations of mechanistic understanding were established, the scope of reactions saw rapid growth. |
Array processing Applications Array_processing > Applications NORSAR has ongoing work to improve array processing to improve monitoring of seismic activity not only in Norway but around the globe. Communications (wireless)Communication can be defined as the process of exchanging of information between two or more parties. The last two decades witnessed a rapid growth of wireless communication systems. |
Hereditary coproporphyria Treatment Hereditary_coproporphyria > Treatment Hospitalization is typically required for administration of hemin, and appropriate drug selection is key to avoid exacerbating symptoms with drugs that interact poorly with porphyrias. Proper drug selection is most difficult when it comes to treatment of the seizures that can accompany HCP, as most anti-seizure medications can make the symptoms worse. Gabapentin and levetiracetam are two anti-seizure drugs that are thought to be safe.In patients where management of symptoms is difficult even with hemin, liver transplant is an option before the symptoms have progressed to advanced paralysis. |
Algebraic multiplicity Overview Eigenvalue,_eigenvector_and_eigenspace > Overview Moreover, these eigenvectors all have an eigenvalue equal to one, because the mapping does not change their length either. Linear transformations can take many different forms, mapping vectors in a variety of vector spaces, so the eigenvectors can also take many forms. For example, the linear transformation could be a differential operator like d d x {\displaystyle {\tfrac {d}{dx}}} , in which case the eigenvectors are functions called eigenfunctions that are scaled by that differential operator, such as Alternatively, the linear transformation could take the form of an n by n matrix, in which case the eigenvectors are n by 1 matrices. |
Photoelectric Effect 20th century Photoelectric_Effect > History > 20th century The paper proposed a simple description of energy quanta, and showed how they explained the blackbody radiation spectrum. His explanation in terms of absorption of discrete quanta of light agreed with experimental results. |
Duane's hypothesis Summary Duane's_hypothesis Duane argued that the way that crystal scattering can be explained by quantization of momentum is not explicable by models based on diffraction by classical waves, as in Bragg's Law. Duane applied his hypothesis to derive the scattering angles of X-rays by a crystal. Subsequently, the principles that Duane advanced were also seen to provide the correct relationships for optical scattering at gratings, and the diffraction of electrons.In the early days of diffraction fine details were not observable because the detectors were inefficient, and the sources were also of low intensities. |
Adaptive noise cancelling Adaptive noise cancelling configuration and concept Adaptive_noise_cancelling > Adaptive noise cancelling configuration and concept This paper sets out the basic concepts of adaptive noise cancelling and summarises subsequent early work and applications. Earlier unpublished efforts to eliminate interference using a second input are also mentioned. This paper remains the main reference for the adaptive noise cancelling concept and to date has been cited by over 2800 scientific paper and 380 patents. The topic is also covered by a number of more recent books. |
Data provenance Architecture Data_lineage > Architecture This design solves 2 problems. It allows horizontal scaling of the lineage store. If a single centralized lineage store was used, then this information had to be carried over the network, which would cause additional network latency. The network latency is also avoided by the use of a distributed lineage store. |
Cardiotoxicity Summary Cardiovascular_toxicity Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. The heart becomes weaker and is not as efficient in pumping blood. Cardiotoxicity may be caused by chemotherapy (a usual example is the class of anthracyclines) treatment and/or radiotherapy; complications from anorexia nervosa; adverse effects of heavy metals intake; the long-term abuse of or ingestion at high doses of certain strong stimulants such as cocaine; or an incorrectly administered drug such as bupivacaine.One of the ways to detect cardiotoxicity at early stages when there is a subclinical dysfunction is by measuring changes in regional function of the heart using strains. |
Air hockey History Air_hockey > History The table top was a sandwich of fiberboard or plexiglass sheets separated by a honeycomb structure. The top surface was drilled with a grid of small holes, and the space between the boards was supplied with low-pressure compressed air, just enough to allow "air pucks" to float over the surface. |
Particle theory Summary Particle_theory The three fundamental interactions known to be mediated by bosons are electromagnetism, the weak interaction, and the strong interaction. Quarks cannot exist on their own but form hadrons. Hadrons that contain an odd number of quarks are called baryons and those that contain an even number are called mesons. |
Stress-strain relationship Thermodynamic basis Spring_Constant > Thermodynamic basis Using the relation between the Cauchy stress and the surface traction, t = n · σ (where n is the unit outward normal to ∂Ω), we have Converting the surface integral into a volume integral via the divergence theorem gives Using the symmetry of the Cauchy stress and the identity we have the following From the definition of strain and from the equations of equilibrium we have Hence we can write and therefore the variation in the internal energy density is given by An elastic material is defined as one in which the total internal energy is equal to the potential energy of the internal forces (also called the elastic strain energy). Therefore, the internal energy density is a function of the strains, U0 = U0(ε) and the variation of the internal energy can be expressed as Since the variation of strain is arbitrary, the stress–strain relation of an elastic material is given by For a linear elastic material, the quantity ∂U0/∂ε is a linear function of ε, and can therefore be expressed as where c is a fourth-rank tensor of material constants, also called the stiffness tensor. We can see why c must be a fourth-rank tensor by noting that, for a linear elastic material, In index notation The right-hand side constant requires four indices and is a fourth-rank quantity. We can also see that this quantity must be a tensor because it is a linear transformation that takes the strain tensor to the stress tensor. We can also show that the constant obeys the tensor transformation rules for fourth-rank tensors. |
5-HT5A receptor Clinical significance 5-HT5A_receptor > Clinical significance The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) has been implicated in a wide range of psychiatric conditions and also has vasoconstrictive and vasodilatory effects. |
Fluent (mathematics) Summary Fluent_(mathematics) Newton described any variable that changed its value as a fluent – for example, the velocity of a ball thrown in the air. The derivative of a fluent is known as a fluxion, the main focus of Newton's calculus. A fluent can be found from its corresponding fluxion through integration. |
Vibronic transition Polyatomic molecules and ions Vibronic_spectroscopy > Polyatomic molecules and ions For polyatomic molecules, progressions are most often observed when the change in bond lengths upon electronic excitation coincides with the change due to a ″totally symmetric″ vibration. This is the same process that occurs in resonance Raman spectroscopy. For example, in formaldehyde (methanal), H2CO, the n → π* transition involves excitation of an electron from a non-bonding orbital to an antibonding pi orbital which weakens and lengthens the C-O bond. This produces a long progression in the C-O stretching vibration. |
Thrombolytic drug Medical uses Clot_buster > Medical uses Diseases where thrombolysis is used: ST elevation myocardial infarction: Large trials have shown that mortality can be reduced using thrombolysis (particularly fibrinolysis) in treating heart attacks. It works by stimulating secondary fibrinolysis by plasmin through infusion of analogs of tissue plasminogen activator (tPA), the protein that normally activates plasmin. Stroke: Thrombolysis reduces major disability or death when given within 3 hours (or perhaps even 6 hours) of ischaemic stroke onset when there are no contraindications to treatment. Massive pulmonary embolism. |
Artificial immune system Summary Artificial_immune_systems In artificial intelligence, artificial immune systems (AIS) are a class of computationally intelligent, rule-based machine learning systems inspired by the principles and processes of the vertebrate immune system. The algorithms are typically modeled after the immune system's characteristics of learning and memory for use in problem-solving. |
Euclidean traveling salesman problem Related problems Travelling_salesman_problem > Description > Related problems An equivalent formulation in terms of graph theory is: Given a complete weighted graph (where the vertices would represent the cities, the edges would represent the roads, and the weights would be the cost or distance of that road), find a Hamiltonian cycle with the least weight. The requirement of returning to the starting city does not change the computational complexity of the problem, see Hamiltonian path problem. Another related problem is the bottleneck travelling salesman problem (bottleneck TSP): Find a Hamiltonian cycle in a weighted graph with the minimal weight of the weightiest edge. For example, avoiding narrow streets with big buses. |
Nutrient recycling Outline Nutrient_cycle > Outline Nutrient cycle is more often used in direct reference to the idea of an intra-system cycle, where an ecosystem functions as a unit. From a practical point, it does not make sense to assess a terrestrial ecosystem by considering the full column of air above it as well as the great depths of Earth below it. While an ecosystem often has no clear boundary, as a working model it is practical to consider the functional community where the bulk of matter and energy transfer occurs. Nutrient cycling occurs in ecosystems that participate in the "larger biogeochemical cycles of the earth through a system of inputs and outputs. ": 425 |
Recovery (metallurgy) Deformed structure Recovery_(metallurgy) > Process > Deformed structure A heavily deformed metal contains a huge number of dislocations predominantly caught up in 'tangles' or 'forests'. Dislocation motion is relatively difficult in a metal with a low stacking fault energy and so the dislocation distribution after deformation is largely random. In contrast, metals with moderate to high stacking fault energy, e.g. aluminum, tend to form a cellular structure where the cell walls consist of rough tangles of dislocations. The interiors of the cells have a correspondingly reduced dislocation density. |
Carbonyl ligand Metallurgical uses Metal_carbonyl > Applications > Metallurgical uses Metal carbonyls are used in several industrial processes. Perhaps the earliest application was the extraction and purification of nickel via nickel tetracarbonyl by the Mond process (see also carbonyl metallurgy).By a similar process carbonyl iron, a highly pure metal powder, is prepared by thermal decomposition of iron pentacarbonyl. Carbonyl iron is used inter alia for the preparation of inductors, pigments, as dietary supplements, in the production of radar-absorbing materials in the stealth technology, and in thermal spraying. |
Fixed gear Advantages and disadvantages Fixed-gear_bicycle > Advantages and disadvantages Alternatively, though far less efficiently, one can brake by stopping the motion of the pedals in mid-rotation, causing the rear wheel to lock in place, allowing the bicycle to skid and slow down from kinetic friction (see below).Descending any significant gradient is more difficult as the rider must spin the cranks at high speed (sometimes at 170 rpm or more), or use the brakes to slow down. Some consider that the enforced fast spin when descending increases suppleness or flexibility, which is said to improve pedalling performance on any type of bicycle; however the performance boost is negligible compared to the benefits of riding a free wheel.Riding fixed is considered by some to encourage a more effective pedaling style, which it is claimed translates into greater efficiency and power when used on a bicycle fitted with a freewheel. It allows for the rider to engage in and practice proper cadence, which is the balanced and rhythmic flow of pedaling, enhancing performance for both cyclist and bicycle.When first riding a fixed gear, a cyclist used to a freewheel may try to freewheel, or coast, particularly when approaching corners or obstacles. |
Cancer Registry SEER Registries Cancer_Registry > Registries by country > United States > SEER Registries The Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute collects and publish data on cancer incidence and survival throughout the United States. The information from population-based cancer registries covers approximately 28 percent of the US population. This coverage includes 26 percent of African Americans, 41 percent of Hispanics, 43 percent of American Indians and Alaska Natives, 54 percent of Asians, and 71 percent of Hawaiian/Pacific Islanders. The SEER program population-based cancer registries include Arizona Indians, Cherokee Nation, Connecticut, Detroit, Georgia Center for Cancer Statistics (Atlanta, Great Georgia, and Rural Georgia), Greater Bay Area Cancer Registry (San Francisco-Oakland and San Jose-Monterey), Greater California, Hawaii, Iowa, Kentucky, Los Angeles, Louisiana, New Jersey, New Mexico, Seattle-Puget Sound, and Utah. Selection of the geographic areas is based on the ability to operate and maintain a high quality population-based cancer reporting system. |
Thermoelectric power source Uses Thermoelectric_generator > Uses The manufacturers of generators for gas pipelines are Global Power Technologies (formerly Global Thermoelectric) (Calgary, Canada) and TELGEN (Russia). Microprocessors generate waste heat. |
Intercellular bridge Cell junctions Intercellular_communication > Communication within an organism > Cell signalling > Cell junctions Complex organisms may have molecules to hold the cells together which can also be involved in intercellular communication. Some binding molecules are termed the extracellular matrix and may involve longer molecules like cellulose for the cell wall in plants or collagen in animals. When the membranes of two cells are close they may form special types of cell junction which come in five broad types, adherens, desmosomes, gap, tight and tricellular junctions. Adherens, desmosomes, tight and tricellular junctions, serve structural roles. |
Morse potential Vibrational states and energies Morse_potential > Vibrational states and energies For energies above n m {\displaystyle n_{m}} , all the possible energy levels are allowed and the equation for E n {\displaystyle E_{n}} is no longer valid. Below n m {\displaystyle n_{m}} , E n {\displaystyle E_{n}} is a good approximation for the true vibrational structure in non-rotating diatomic molecules. In fact, the real molecular spectra are generally fit to the form1 E n / h c = ω e ( n + 1 / 2 ) − ω e χ e ( n + 1 / 2 ) 2 {\displaystyle E_{n}/hc=\omega _{e}(n+1/2)-\omega _{e}\chi _{e}(n+1/2)^{2}\,} in which the constants ω e {\displaystyle \omega _{e}} and ω e χ e {\displaystyle \omega _{e}\chi _{e}} can be directly related to the parameters for the Morse potential. As is clear from dimensional analysis, for historical reasons the last equation uses spectroscopic notation in which ω e {\displaystyle \omega _{e}} represents a wavenumber obeying E = h c ω {\displaystyle E=hc\omega } , and not an angular frequency given by E = ℏ ω {\displaystyle E=\hbar \omega } . |
Controllable pitch propeller Summary Controllable_pitch_propeller Vessels with medium or high speed diesel or gasoline engines use a reduction gear to reduce the engine output speed to an optimal propeller speed—although the large low speed diesels, whose cruising RPM is in the 80 to 120 range, are usually direct drive with direct-reversing engines. While an FVPP-equipped vessel needs either a reversing gear or a reversible engine to reverse, a CPP vessel may not. On a large ship the CPP requires a hydraulic system to control the position of the blades. |
Rational canonical form Motivation Rational_canonical_form > Motivation A basis of such a subspace is obtained by taking v and its successive images as long as they are linearly independent. The matrix of the linear operator with respect to such a basis is the companion matrix of a monic polynomial; this polynomial (the minimal polynomial of the operator restricted to the subspace, which notion is analogous to that of the order of a cyclic subgroup) determines the action of the operator on the cyclic subspace up to isomorphism, and is independent of the choice of the vector v generating the subspace. A direct sum decomposition into cyclic subspaces always exists, and finding one does not require factoring polynomials. |
M-Theory (learning framework) Invariant representations M-Theory_(learning_framework) > Intuition > Invariant representations For training and testing of the first instance, images with arbitrary viewpoints were used. Another instance received only images seen from a particular viewpoint, which was equivalent to training and testing the system on invariant representation of the images. One can see that the second classifier performed quite well even after receiving a single example from each category, while performance of the first classifier was close to random guess even after seeing 20 examples. |
Stem cell differentiation Histone acetylation and methylation Stem_cell_differentiation > Epigenetic control > Mechanisms of epigenetic regulation > Nucleosome positioning > Histone acetylation and methylation DNA-nucleosome interactions are characterized by two states: either tightly bound by nucleosomes and transcriptionally inactive, called heterochromatin, or loosely bound and usually, but not always, transcriptionally active, called euchromatin. The epigenetic processes of histone methylation and acetylation, and their inverses demethylation and deacetylation primarily account for these changes. The effects of acetylation and deacetylation are more predictable. An acetyl group is either added to or removed from the positively charged Lysine residues in histones by enzymes called histone acetyltransferases or histone deactylases, respectively. |
Algorithm characterization 1936, 1963, 1964 Gödel's characterization Algorithm_characterization > 1936, 1963, 1964 Gödel's characterization J. Math., vol. 58 (1936) ).Church's definitions encompass so-called "recursion" and the "lambda calculus" (i.e. the λ-definable functions). |
Diffusion capacity Blood CO levels may not be negligible Diffusing_capacity > Interpretation > Blood CO levels may not be negligible Alveolar hemorrhage Goodpasture's syndrome, polycythemia, left to right intracardiac shunts, due increase in volume of blood exposed to inspired gas. Asthma due to better perfusion of apices of lung. This is caused by increase in pulmonary arterial pressure and/or due to more negative pleural pressure generated during inspiration due to bronchial narrowing. |
Location arithmetic Napier's Method Location_arithmetic > Square roots > Napier's Method This process requires one to add counters to the abacus (board) to make square figures. The top of page 149 shows diagrams that explain this process. Begin by placing a single counter on the board (it will actually go on one of the dotted squares). |
Hemostasis Steps of mechanism Hemostasis > Steps of mechanism Platelets play one of major roles in the hemostatic process. When platelets come across the injured endothelium cells, they change shape, release granules and ultimately become ‘sticky’. Platelets express certain receptors, some of which are used for the adhesion of platelets to collagen. |
Treatment modality Lines of therapy Medical_therapy > Types of therapies > By chronology, priority, or intensity > Lines of therapy If a first-line therapy either fails to resolve the issue or produces intolerable side effects, additional (second-line) therapies may be substituted or added to the treatment regimen, followed by third-line therapies, and so on. An example of a context in which the formalization of treatment algorithms and the ranking of lines of therapy is very extensive is chemotherapy regimens. Because of the great difficulty in successfully treating some forms of cancer, one line after another may be tried. |
Multidimensional empirical mode decomposition Motivation Multidimensional_empirical_mode_decomposition > Motivation Multidimensional empirical mode decomposition is a popular method because of its applications in many fields, such as texture analysis, financial applications, image processing, ocean engineering, seismic research, etc. Several methods of Empirical Mode Decomposition have been used to analyze characterization of multidimensional signals. |
Black body spectrum Further explanation Black-body_radiation > Theory > Further explanation Calculating the blackbody curve was a major challenge in theoretical physics during the late nineteenth century. The problem was solved in 1901 by Max Planck in the formalism now known as Planck's law of blackbody radiation. By making changes to Wien's radiation law (not to be confused with Wien's displacement law) consistent with thermodynamics and electromagnetism, he found a mathematical expression fitting the experimental data satisfactorily. |
Object Database Overview Object_persistence > Overview As the usage of web-based technology increases with the implementation of Intranets and extranets, companies have a vested interest in OODBMSs to display their complex data. Using a DBMS that has been specifically designed to store data as objects gives an advantage to those companies that are geared towards multimedia presentation or organizations that utilize computer-aided design (CAD).Some object-oriented databases are designed to work well with object-oriented programming languages such as Delphi, Ruby, Python, JavaScript, Perl, Java, C#, Visual Basic .NET, C++, Objective-C and Smalltalk; others such as JADE have their own programming languages. OODBMSs use exactly the same model as object-oriented programming languages. |
Jordan canonical form Invariant subspace decompositions Jordan_canonical_form > Consequences > Invariant subspace decompositions Spectral projections are mutually orthogonal in the sense that P(λi ; A) P(vj ; A) = 0 if i ≠ j. Also they commute with A and their sum is the identity matrix. Replacing every vi in the Jordan matrix J by one and zeroing all other entries gives P(vi ; J), moreover if U J U−1 is the similarity transformation such that A = U J U−1 then P(λi ; A) = U P(λi ; J) U−1. They are not confined to finite dimensions. |
Social Trends Scope Social_Trends > Scope It covers various different topics and policy areas e.g. housing, crime, income and wealth, transport, population. |
Hardness tester Relation between hardness number and stress-strain curve Hardness_tester > Relation between hardness number and stress-strain curve This applies to the outcome of an indentation test (with a given size and shape of indenter, and a given applied load). However, while a hardness number thus depends on the stress-strain relationship, inferring the latter from the former is far from simple and is not attempted in any rigorous way during conventional hardness testing. (In fact, the Indentation Plastometry technique, which involves iterative FEM modelling of an indentation test, does allow a stress-strain curve to be obtained via indentation, but this is outside the scope of conventional hardness testing.) |
Approximate Bayesian Computation Prior distribution and parameter ranges Approximate_Bayesian_Computation > Pitfalls and remedies > General risks in statistical inference exacerbated in ABC > Prior distribution and parameter ranges In principle, uninformative and flat priors, that exaggerate our subjective ignorance about the parameters, may still yield reasonable parameter estimates. However, Bayes factors are highly sensitive to the prior distribution of parameters. Conclusions on model choice based on Bayes factor can be misleading unless the sensitivity of conclusions to the choice of priors is carefully considered. |
Tomaž Prosen Research Tomaž_Prosen > Research Tomaž Prosen is primarily known for providing the first exact solutions for models of open quantum many-body systems and for the discovery of novel kinds of quantum conservation laws that settled long-standing questions about the nature of transport in fundamental models of low-dimensional quantum materials, such as the Heisenbeg spin chains and the one-dimensional Hubbard model. The latter work also provided a full description of canonical ensembles of quantum integrable systems paving the way for extensions of thermodynamics to integrable systems. He is also known for pioneering a novel approach for establishing quantum chaos in spin-1/2 systems, for which previously known semi-classical methods fail. This approach challenged conventional beliefs in theoretical physics by providing an exact solution to the dynamics of a chaotic model. |
PID Controller Basing proportional action on PV Proportional–integral–derivative_controller > Alternative nomenclature and forms > Basing proportional action on PV Most commercial control systems offer the option of also basing the proportional action solely on the process variable. This means that only the integral action responds to changes in the setpoint. The modification to the algorithm does not affect the way the controller responds to process disturbances. |
Statistical data Meaning Data > Meaning Data, information, knowledge, and wisdom are closely related concepts, but each has its role concerning the other, and each term has its meaning. According to a common view, data is collected and analyzed; data only becomes information suitable for making decisions once it has been analyzed in some fashion. One can say that the extent to which a set of data is informative to someone depends on the extent to which it is unexpected by that person. The amount of information contained in a data stream may be characterized by its Shannon entropy. |
Acute abdomen Workup Acute_abdomen > Workup Stable patients presenting to accident and emergency department or ER (emergency room) with severe abdominal pain will almost always have an abdominal x-ray and/or a CT scan. These tests can provide a differential diagnosis between simple and complex pathologies. However, in the unstable patient, fluid resuscitation and a FAST-ultrasound are done first, and if the latter is positive for free fluid, straight to surgery. |
Parkinson's disease Prognosis Parkinson's_disease > Prognosis These symptoms, especially cognitive decline, greatly increase disability.The life expectancy of people with PD is reduced. Mortality ratios are around twice those of unaffected people. Cognitive decline and dementia, old age at onset, a more advanced disease state, and presence of swallowing problems are all mortality risk factors. |
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