page_content stringlengths 51 3.15k |
|---|
Small nucleolar RNA snR57 Summary Small_nucleolar_RNA_snR57 In molecular biology, snoRNA snR57 is a non-coding RNA (ncRNA) molecule which functions in the modification of other small nuclear RNAs (snRNAs). This type of modifying RNA is usually located in the nucleolus of the eukaryotic cell which is a major site of snRNA biogenesis. It is known as a small nucleolar RNA (snoRNA) and also often referred to as a guide RNA. |
C programming Summary C_programming_language C has been standardized by ANSI since 1989 (ANSI C) and by the International Organization for Standardization (ISO). C is an imperative procedural language, supporting structured programming, lexical variable scope and recursion, with a static type system. It was designed to be compiled to provide low-level access to memory and language constructs that map efficiently to machine instructions, all with minimal runtime support. Despite its low-level capabilities, the language was designed to encourage cross-platform programming. A standards-compliant C program written with portability in mind can be compiled for a wide variety of computer platforms and operating systems with few changes to its source code.Since 2000, C has consistently ranked among the top two languages in the TIOBE index, a measure of the popularity of programming languages. |
E = mc² Alternative version Mass–energy_equivalence > History > Einstein: mass–energy equivalence > Alternative version {\displaystyle \Delta P={v \over c}{E \over 2c}.} The left-moving light carries a little less momentum, by the same amount ΔP. |
Outcast (person) Summary Outcast_(person) An outcast is someone who is rejected or cast out, as from home or from society or in some way excluded, looked down upon, or ignored. In common English speech, an outcast may be anyone who does not fit in with normal society, which can contribute to a sense of isolation. Compare the concept of sending to Coventry. |
Nanoinjection Electrophoretic Injection Nanoinjection > Techniques > Electrophoretic Injection Electrophoretic injection remains the most common form of nanoinjection. Just as with the other methods, a lance ten times smaller than that of microinjection is used. Preparing the lance for injection, a positive charge is applied, attracting the negatively-charged DNA to its tip. After the lance has reached a desired depth within the cell, the charge is reversed, repelling the DNA into the cell. The typical injection voltages are ±20 V, but can be as low as 50-100 mV. |
Peng-Robinson equation of state The BWR equation of state Peng-Robinson_equation_of_state > Virial equations of state > The BWR equation of state The second virial coefficient is monotonically decreasing as temperature is lowered. The third virial coefficient is monotonically increasing as temperature is lowered. The Lee–Kesler equation of state is based on the corresponding states principle, and is a modification of the BWR equation of state. |
Geometric drawing Summary Geometric_drawing Geometric drawing consists of a set of processes for constructing geometric shapes and solving problems with the use of a ruler without graduation and the compass (drawing tool). Modernly, such studies can be done with the aid of software, which simulates the strokes performed by these instruments.For ancient mathematicians, geometry could not do without the methods of geometric constructions, necessary for understanding, theoretical enrichment, and problem-solving. The accuracy and precision required of geometric drawing make it an important ally in the application of geometric concepts in significant areas of human knowledge, such as architecture, engineering, industrial design, among others. The process of geometric drawing is based on constructions with a ruler and compass, which in turn are based on the first three postulates of Euclid's Elements. The historical importance of rulers and compasses as instruments in solving geometric problems leads many authors to limit Geometric Drawing to the representation and solution of geometric figures in the plane.With the development of computer-aided design (CAD) programs, geometric drawing has become more important in teaching-learning processes (development of spatial faculties) than the more imprecise tracing offered by rulers and compasses, when taking into account the precision of computer systems. |
Behavioral epigenetics Stress Behavioral_epigenetics > Research into epigenetics in psychology > Stress This research provides evidence for an underlying epigenetic mechanism. Further support comes from experiments with the same setup, using drugs that can increase or decrease methylation. |
Coase theorem Game-theoretic critique: hold-out, free-rider problems, complete information assumption Coase_theorem > Criticism > Criticisms of the applicability of the theorem > Game-theoretic critique: hold-out, free-rider problems, complete information assumption Rather it is more likely to be determined by a host of factors including the structure of the negotiations, discount rates and other factors of relative bargaining strength (cf. Ariel Rubenstein). If the negotiation is not a single shot game, then reputation effects may also occur, which can dramatically distort outcomes and may even lead to failed negotiation (cf. David M. Kreps, also the chainstore paradox). |
Nuclear magnetic resonance in porous media nan NMR_in_porous_media > T 2 {\displaystyle T_{2}} relaxation For fully brine saturated porous media, three different mechanisms contribute to the relaxation: bulk fluid relaxation, surface relaxation, and relaxation due to gradients in the magnetic field. In the absence of magnetic field gradients, the equations describing the relaxation are: δ M δ t = D 0 ∇ 2 M − M T 2 b {\displaystyle {\frac {\delta M}{\delta t}}=D_{0}\nabla ^{2}M-{\frac {M}{T_{2b}}}} D 0 ∇ M + ρ M = 0 {\displaystyle D_{0}\nabla M+\rho M=0} on Swith the initial condition t = 0 {\displaystyle t=0} and M = M 0 {\displaystyle M=M_{0}} where D 0 {\displaystyle D_{0}} is the self-diffusion coefficient. The governing diffusion equation can be solved by a 3D random walk algorithm. Initially, the walkers are launched at random positions in the pore space. |
Virtual battlefield The simulation spectrum Virtual_battlefield > The simulation spectrum At other times one or other of the teams might be replaced by a computer-simulated opponent (known as an agent or automaton). This can reduce the umpires' role to interpreter of the data produced by the agent, or remove the need for an umpire altogether. Most commercial wargames designed to run on computers (such as Blitzkrieg, the Total War series, Civilization games, and even Arma 2) fall into this category. |
Sample variance Summary Variance One, as discussed above, is part of a theoretical probability distribution and is defined by an equation. The other variance is a characteristic of a set of observations. When variance is calculated from observations, those observations are typically measured from a real world system. |
Approximate Bayesian Computation Software Approximate_Bayesian_Computation > Software A number of software packages are currently available for application of ABC to particular classes of statistical models. The suitability of individual software packages depends on the specific application at hand, the computer system environment, and the algorithms required. |
Air-Cobot Navigation in the airport or the factory Air-Cobot > Autonomous navigation > Navigation in the airport or the factory In an outdoor environment, the robot is able to go to the inspection site by localizing through Global Positioning System (GPS) data. The GPS device developed by M3 Systems allows geofencing. At the airport, the robot operates in dedicated navigation corridors respecting speed limits. |
Reaction intermediate Methane chlorination Reaction_product > Common reaction intermediates > Radicals > Methane chlorination -> CCl3. + H-Cl}}} These new radical carbon containing species now react with a second Cl2 molecule. |
Statistical learning Model assessments Statistical_learning > Model assessments Classification of machine learning models can be validated by accuracy estimation techniques like the holdout method, which splits the data in a training and test set (conventionally 2/3 training set and 1/3 test set designation) and evaluates the performance of the training model on the test set. In comparison, the K-fold-cross-validation method randomly partitions the data into K subsets and then K experiments are performed each respectively considering 1 subset for evaluation and the remaining K-1 subsets for training the model. In addition to the holdout and cross-validation methods, bootstrap, which samples n instances with replacement from the dataset, can be used to assess model accuracy.In addition to overall accuracy, investigators frequently report sensitivity and specificity meaning True Positive Rate (TPR) and True Negative Rate (TNR) respectively. |
Airflow Simulation Airflow > Simulation Air flow can be simulated using Computational Fluid Dynamics (CFD) modeling, or observed experimentally through the operation of a wind tunnel. This may be used to predict airflow patterns around automobiles, aircraft, and marine craft, as well as air penetration of a building envelope. Because CFD models "also track the flow of solids through a system," they can be used for analysis of pollution concentrations in indoor and outdoor environments. Particulate matter generated indoors generally comes from cooking with oil and combustion activities such as burning candles or firewood. In outdoor environments, particulate matter comes from direct sources such as internal combustion engine vehicles’ (ICEVs) tailpipe emissions from burning fuel (petroleum products), windblow and soil, and indirectly from atmospheric oxidation of volatile organic compounds (VOCs), sulfur dioxide (SO2), and nitrogen oxide (NOx) emissions. |
Conceptual model Conceptual model vs. semantics model Conceptual_model > Models in philosophy and science > Conceptual model vs. semantics model Conceptual Models and semantic models have many similarities, however the way they are presented, the level of flexibility and the use are different. Conceptual models have a certain purpose in mind, hence the core semantic concepts are predefined in a so-called meta model. This enables a pragmatic modelling but reduces the flexibility, as only the predefined semantic concepts can be used. Samples are flow charts for process behaviour or organisational structure for tree behaviour. |
Spacetime Dewan–Beran–Bell spaceship paradox Space-time_continuum > Beyond the basics > Acceleration > Dewan–Beran–Bell spaceship paradox : 106, 120–122 The problem with the first argument is that there is no "frame of the spaceships." There cannot be, because the two spaceships measure a growing distance between the two. Because there is no common frame of the spaceships, the length of the string is ill-defined. |
Key authentication Authentication using Shared Keys Public-key_authentication > Authentication using Shared Keys For key authentication using the traditional symmetric key cryptography, this is the problem of assuring that there is no man-in-the-middle attacker who is trying to read or spoof the communication. There are various algorithms used now-a-days to prevent such attacks. The most common among the algorithms are Diffie–Hellman key exchange, authentication using Key distribution center, kerberos and Needham–Schroeder protocol. Other methods that can be used include Password-authenticated key agreement protocols etc. |
Glossary of electrical and electronics engineering I Glossary_of_electrical_and_electronics_engineering > I infinite impulse responseA filter which, mathematically, never gets to a zero effect of an impulse at its input, though practically the response may become negligible after a definite time. information applianceConceptually, an embedded computer system with a specialized user interface designed to simplify one task, such as e-mail or photos; a modern smart phone approaches this concept. information theoryThe mathematical study of information. |
Algorithmic problem By implementation Algorithmic_method > Classification > By implementation Serial, parallel or distributed Algorithms are usually discussed with the assumption that computers execute one instruction of an algorithm at a time. Those computers are sometimes called serial computers. An algorithm designed for such an environment is called a serial algorithm, as opposed to parallel algorithms or distributed algorithms. |
Electrical impedance Complex voltage and current Complex_Impedance > Complex voltage and current To simplify calculations, sinusoidal voltage and current waves are commonly represented as complex-valued functions of time denoted as V {\displaystyle V} and I {\displaystyle I} . V = | V | e j ( ω t + ϕ V ) , I = | I | e j ( ω t + ϕ I ) . {\displaystyle {\begin{aligned}V&=|V|e^{j(\omega t+\phi _{V})},\\I&=|I|e^{j(\omega t+\phi _{I})}.\end{aligned}}} The impedance of a bipolar circuit is defined as the ratio of these quantities: Z = V I = | V | | I | e j ( ϕ V − ϕ I ) . {\displaystyle Z={\frac {V}{I}}={\frac {|V|}{|I|}}e^{j(\phi _{V}-\phi _{I})}.} Hence, denoting θ = ϕ V − ϕ I {\displaystyle \theta =\phi _{V}-\phi _{I}} , we have | V | = | I | | Z | , ϕ V = ϕ I + θ . {\displaystyle {\begin{aligned}|V|&=|I||Z|,\\\phi _{V}&=\phi _{I}+\theta .\end{aligned}}} The magnitude equation is the familiar Ohm's law applied to the voltage and current amplitudes, while the second equation defines the phase relationship. |
Combination gun Summary Combination_gun A combination gun is a firearm that usually comprises at least one rifled barrel and one smoothbore barrel, that is typically used with shot or some type of shotgun slug. Most have been break-action guns, although there have been other designs as well. Combination guns using one rifled and one smoothbore barrel are commonly found in an over-and-under configuration, while the side-by-side configuration is usually referred to as a cape gun. A combination gun with more than two barrels are called a drilling (German for "triplet") with three barrels, a vierling (German for "quadruplet") with four barrels, and a fünfling (German for "quintuplet") with five barrels. Combination guns generally use rimmed cartridges, as rimless cartridges are usually more difficult to extract from a break-action firearm. |
Antiretroviral drug Virologic response Antiretroviral_treatment > Response to therapy > Virologic response The importance of the final results of the PARTNER 2 study were described by the medical director of the Terrence Higgins Trust as "impossible to overstate", while lead author Alison Rodger declared that the message that "undetectable viral load makes HIV untransmittable ... can help end the HIV pandemic by preventing HIV transmission." The authors summarised their findings in The Lancet as follows: Our results provide a similar level of evidence on viral suppression and HIV transmission risk for gay men to that previously generated for heterosexual couples and suggest that the risk of HIV transmission in gay couples through condomless sex when HIV viral load is suppressed is effectively zero. Our findings support the message of the U=U (undetectable equals untransmittable) campaign, and the benefits of early testing and treatment for HIV. This result is consistent with the conclusion presented by Anthony S. Fauci, the Director of the National Institute of Allergy and Infectious Diseases for the U.S. National Institutes of Health, and his team in a viewpoint published in the Journal of the American Medical Association, that U=U is an effective HIV prevention method when an undetectable viral load is maintained. |
Tensile strain Green strain Strain_tensor > Strain measures > Green strain The Green strain is defined as: |
Pollutant-induced abnormal behaviour Birds Pollutant-induced_abnormal_behaviour > Noise and light pollution > Noise pollution > Birds A negative correlation was found between the noise intensity of an area and the probability that a long-eared owl will reside in that region. Suggested explanations for this outcome are that hunting efficiency was diminished and communication was less effective. Noise pollution also affects conspecific communication. |
Amtolmetin guacil Mechanism of action Amtolmetin_guacil > Mechanism of action Amtolmetin guacil stimulates capsaicin receptors present on gastrointestinal walls, because of presence of vanillic moiety and also releases NO which is gastro protective. It also inhibits prostaglandin synthesis and cyclooxygenase (COX). == References == |
Prestack Summary Prestack In algebraic geometry, a prestack F over a category C equipped with some Grothendieck topology is a category together with a functor p: F → C satisfying a certain lifting condition and such that (when the fibers are groupoids) locally isomorphic objects are isomorphic. A stack is a prestack with effective descents, meaning local objects may be patched together to become a global object. Prestacks that appear in nature are typically stacks but some naively constructed prestacks (e.g., groupoid scheme or the prestack of projectivized vector bundles) may not be stacks. |
Library sort Algorithm Library_sort > Implementation > Algorithm This can be done by linearly moving towards left or right side of the array if you hit an empty space in the middle element. Insertion: Inserting the element in the position found and swapping the following elements by 1 position till an empty space is hit. This is done in logarithmic time, with high probability. |
Missense mRNA Biogenesis Missense_mRNA > Biogenesis Spontaneous mutations occur during the DNA replication process where a non-complementary nucleotide is deposited by the DNA polymerase in the extension phase. The consecutive round of replication would result in a point mutation. If the resulting mRNA codon is one that changes the amino acid, a missense mRNA would be detected. |
Modulus of complex number Terminology and notation Magnitude_of_a_complex_number > Terminology and notation In 1806, Jean-Robert Argand introduced the term module, meaning unit of measure in French, specifically for the complex absolute value, and it was borrowed into English in 1866 as the Latin equivalent modulus. The term absolute value has been used in this sense from at least 1806 in French and 1857 in English. The notation |x|, with a vertical bar on each side, was introduced by Karl Weierstrass in 1841. |
Mechanical filter Piezoelectric Mechanical_filter > Transducers > Piezoelectric A piezoelectric material is one which changes shape when an electric field is applied. In reverse, it produces an electric field when it is distorted. A piezoelectric transducer, in essence, is made simply by plating electrodes on to the piezoelectric material. |
Strong derivative Directional derivatives Order_of_derivation > In higher dimensions > Directional derivatives In some cases it may be easier to compute or estimate the directional derivative after changing the length of the vector. Often this is done to turn the problem into the computation of a directional derivative in the direction of a unit vector. To see how this works, suppose that v = λu where u is a unit vector in the direction of v. Substitute h = k/λ into the difference quotient. |
Nanoscale vacuum-channel transistor Simplified operation Nanoscale_vacuum-channel_transistor > Simplified operation A gate electrode is used to control the current flow through the vacuum-channel. Despite the name, vacuum-channel transistors do not need to be evacuated. The gap traversed by the electrons is so small that collisions with molecules of gas at atmospheric pressure are infrequent enough not to matter. |
MO diagram Heteronuclear diatomics Molecular_orbital_diagram > Heteronuclear diatomics In heteronuclear diatomic molecules, mixing of atomic orbitals only occurs when the electronegativity values are similar. In carbon monoxide (CO, isoelectronic with dinitrogen) the oxygen 2s orbital is much lower in energy than the carbon 2s orbital and therefore the degree of mixing is low. The electron configuration 1σ21σ*22σ22σ*21π43σ2 is identical to that of nitrogen. The g and u subscripts no longer apply because the molecule lacks a center of symmetry. |
EuroMatrixPlus Software and data EuroMatrixPlus > Outcome > Software and data Here is a list of software and data that were released by the project: Appraise – an open source tool for manual evaluation of MT output BURGER – Bulgarian Resource BulTreeBank – Treebank of Bulgarian CSLM toolkit – free tool for training continuous space language models (CSLM) to large tasks Caitra – tool for post-editing MT results Europarl – European Parliament parallel corpus IRSTLM toolkit – tool for training language models Joshua – an open-source statistical machine translation decoder for hierarchical and syntax-based MT MT Server Land – an open-source architecture for MT Moses – statistical MT MultiUN Corpora – parallel corpus extracted from the United Nations Website PCEDT 2.0 – Prague Czech-English Dependency Treebank PEDT 2.0 – English part of the Prague Czech-English Dependency Treebank Slovak corpora – English-Slovak and Czech-Slovak as well as a Slovak-English and a Slovak-Czech parallel corpus Slovak treebank – A dependency treebank TermEx – RBMT-Suited Statistical Terminology Extraction Tool Treex, TectoMT |
Linear seismic inversion Temperature inversion from Marescot (2010) Linear_seismic_inversion > Inversion examples > Temperature inversion from Marescot (2010) These experimental data were inverted to obtain earth parameter values of a = 0.5 {\displaystyle a=0.5} and b = 18 ∘ C {\displaystyle b=18^{\circ }C} . For a more general case with large number of temperature observations, Fig. 4 shows the final linear forward model obtained from using the inverted values of a {\displaystyle a} and b {\displaystyle b} . The figure shows a good match between experimental and numerical data. |
Spectro-Polarimetric High-Contrast Exoplanet Research Instrument description Spectro-Polarimetric_High-Contrast_Exoplanet_Research > Instrument description The Infrared Dual-band Imager and Spectrograph (IRDIS) has a field of view of 11" x 12.5" with a pixel scale of 12.25 mas (milliarcsecond). IRDIS can provide classical imaging. Alternatively, it can be configured to provide simultaneous dual-band imaging using two different narrow bandpass filters targeting different spectral features, or it can be configured to provide simultaneous imaging from two crossed polarizers. |
Multiplicative partitions of factorials Summary Multiplicative_partitions_of_factorials that have length n {\textstyle n} , and find the partition whose first factor is the largest. (Since the first factor in a partition is the smallest within that partition, this means finding the maximum of all the minima.) Call this factor m ( n ) {\textstyle m(n)} . |
Autoimmune polyendocrine syndrome type 1 Pathophysiology Autoimmune_polyendocrine_syndrome_type_1 > Pathophysiology This leads to damage to endocrine organs. Common problems include hypercalcaemia and nephrocalcinosis (due to a lack of calcitonin from the thyroid), and pituitary problems (such as growth hormone deficiency). Antibodies against NLRP5 may lead to hypoparathyroidism. |
Proteolytic degradation Cleavage of polyproteins Proteolytic_degradation > Biological functions > Post-translational proteolytic processing > Cleavage of polyproteins Many viruses also produce their proteins initially as a single polypeptide chain that were translated from a polycistronic mRNA. This polypeptide is subsequently cleaved into individual polypeptide chains. Common names for the polyprotein include gag (group-specific antigen) in retroviruses and ORF1ab in Nidovirales. The latter name refers to the fact that a slippery sequence in the mRNA that codes for the polypeptide causes ribosomal frameshifting, leading to two different lengths of peptidic chains (a and ab) at an approximately fixed ratio. |
Phylogenetic profiling Summary Evolutionary_profiles Phylogenetic profiling is a bioinformatics technique in which the joint presence or joint absence of two traits across large numbers of species is used to infer a meaningful biological connection, such as involvement of two different proteins in the same biological pathway. Along with examination of conserved synteny, conserved operon structure, or "Rosetta Stone" domain fusions, comparing phylogenetic profiles is a designated "post-homology" technique, in that the computation essential to this method begins after it is determined which proteins are homologous to which. A number of these techniques were developed by David Eisenberg and colleagues; phylogenetic profile comparison was introduced in 1999 by Pellegrini, et al. |
Transport triggered architecture Branches Transport_triggered_architecture > Structure > Branches All processors, including TTA processors, include control flow instructions that alter the program counter, which are used to implement subroutines, if-then-else, for-loop, etc. The assembly language for TTA processors typically includes control flow instructions such as unconditional branches (JUMP), conditional relative branches (BNZ), subroutine call (CALL), conditional return (RETNZ), etc. that look the same as the corresponding assembly language instructions for other processors. Like all other operations on a TTA machine, these instructions are implemented as "move" instructions to a special function unit. TTA implementations that support conditional execution, such as the sTTAck and the first MOVE prototype, can implement most of these control flow instructions as a conditional move to the program counter.TTA implementations that only support unconditional data transports, such as the Maxim Integrated MAXQ, typically have a special function unit tightly connected to the program counter that responds to a variety of destination addresses. Each such address, when used as the destination of a "move", has a different effect on the program counter—each "relative branch " instruction has a different destination address for each condition; and other destination addresses are used CALL, RETNZ, etc. |
Telomerase Targeted apoptosis EST1 > Clinical implications > Cancer > Targeted apoptosis Another independent approach is to use oligoadenylated anti-telomerase antisense oligonucleotides and ribozymes to target telomerase RNA, reducing dissociation and apoptosis (Figure 5). The fast induction of apoptosis through antisense binding may be a good alternative to the slower telomere shortening. |
Painter's algorithm Algorithm Painter's_algorithm > Algorithm Conceptually Painter's Algorithm works as follows: Sort each polygon by depth Place each polygon from the farthest polygon to the closest polygon |
Mitochondrial fusion Apoptosis Mitochondrial_fusion > Apoptosis The balance between mitochondrial fusion and fission in cells is dictated by the up-and-down regulation of mitofusins, OPA1/Mgm1, and Drp1/Dnm1. Apoptosis, or programmed cell death, begins with the breakdown of mitochondria into smaller pieces. This process results from up-regulation of Drp1/Dnm1 and down-regulation of mitofusins. Later in the apoptosis cycle, an alteration of OPA1/Mgm1 activity within the inner mitochondrial membrane occurs. |
Epidemiological transition Current evidence Epidemiological_transition > Current evidence The majority of the literature on the epidemiological transition that was published since these seminal papers confirms the context-specific nature of the epidemiological transition: while there is an overall all-cause mortality decline, the nature of cause-specific mortality declines differs across contexts. Increasing obesity rates in high-income countries are further confirming the epidemiological transition theory as the epidemic leads to an increase in NCDs. The picture is more nuanced in low- and middle-income countries, where there are signs of a protracted transition with the double burden of communicable and noncommunicable disease. A recent review of cause-specific mortality rates from 12 low- and middle-income countries in Asia and sub-Saharan Africa by Santosa and Byass (2016) shows that broadly, low- and middle-income countries are rapidly transitioning to lower total mortality and lower infectious disease mortality. |
Volume and displacement indicators for an architectural structure Objective Volume_and_displacement_indicators_for_an_architectural_structure > Objective Furthermore, the resistance of the structure is not the only criterion to take into account. In many cases, it is also important to ensure that it will not undergo excessive deformation under static loads or that it does not vibrate to inconvenient or dangerous levels when subjected to dynamic loads. Volume and displacement indicators, W and Δ, discovered by Philippe Samyn in August 1997, are useful tools in this regard. This approach does not take into account phenomena of elastic instability. It can indeed be shown that it is always possible to design a structure so that this effect becomes negligible. |
Byte code Execution Byte_code > Execution A bytecode program may be executed by parsing and directly executing the instructions, one at a time. This kind of bytecode interpreter is very portable. Some systems, called dynamic translators, or just-in-time (JIT) compilers, translate bytecode into machine code as necessary at runtime. This makes the virtual machine hardware-specific but does not lose the portability of the bytecode. |
Philosophy of information Logic of information Philosophy_of_information > History > Logic of information The logic of information, also known as the logical theory of information, considers the information content of logical signs and expressions along the lines initially developed by Charles Sanders Peirce. |
Inner satellite Inner satellites of Neptune Inner_moon > List of inner satellites > Inner satellites of Neptune Neptune has seven known inner satellites: Naiad Thalassa Despina Galatea − inner shepherd satellite of the very narrow Adams ring, which is broken into arcs Larissa Hippocamp ProteusIt is thought that they are rubble piles re-accreted from fragments of Neptune's original satellites (inner or not). These were strongly perturbed by Triton in the period soon after that moon's capture into a very eccentric initial orbit. The perturbations led to collisions between the satellites, and that portion of the fragments that were not lost re-accreted into the present inner satellites after Triton's orbit became circularised. |
Y-aromaticity Theory Y-aromaticity > Theory This means that, instead of being tied to one atom of carbon, each electron is shared by all six in the ring. Thus, there are not enough electrons to form double bonds on all the carbon atoms, but the "extra" electrons strengthen all of the bonds on the ring equally. The resulting molecular orbital is considered to have π symmetry. |
RNA modification Transfer RNA modifications RNA_editing > Types of RNA > Transfer RNA modifications For example, in eukaryotes an adenosine at position 34 of the anticodon can be converted to inosine. Inosine is a modification that is able to base-pair with cytosine, adenine, and uridine.Another commonly modified base in tRNA is the position adjacent to the anticodon. Position 37 is often hypermodified with bulky chemical modifications. These modifications prevent frameshifting and increase anticodon-codon binding stability through stacking interactions. |
Phred quality score Summary Phred_score The FASTQ format encodes phred scores as ASCII characters alongside the read sequences. Phred quality scores have become widely accepted to characterize the quality of DNA sequences, and can be used to compare the efficacy of different sequencing methods. Perhaps the most important use of Phred quality scores is the automatic determination of accurate, quality-based consensus sequences. |
Symbolic AI Machine learning Symbolic_AI > History > Adding in more rigorous foundations, 1993–2011 > Machine learning When problem-solving fails, querying the expert to either learn a new exemplar for problem-solving or to learn a new explanation as to exactly why one exemplar is more relevant than another. For example, the program Protos learned to diagnose tinnitus cases by interacting with an audiologist. Learning by analogy—constructing problem solutions based on similar problems seen in the past, and then modifying their solutions to fit a new situation or domain. |
Alexander–Spanier cohomology Summary Alexander-Spanier_cohomology In mathematics, particularly in algebraic topology, Alexander–Spanier cohomology is a cohomology theory for topological spaces. |
Antiparallel vectors Generalizations Vector_direction > Overview > Generalizations In physics, as well as mathematics, a vector is often identified with a tuple of components, or list of numbers, that act as scalar coefficients for a set of basis vectors. When the basis is transformed, for example by rotation or stretching, then the components of any vector in terms of that basis also transform in an opposite sense. The vector itself has not changed, but the basis has, so the components of the vector must change to compensate. The vector is called covariant or contravariant, depending on how the transformation of the vector's components is related to the transformation of the basis. |
Planetary transit Kepler / K2 Planetary_transit > Missions > Kepler / K2 The Kepler satellite served the Kepler mission between 7 March 2009 and 11 May 2013, where it observed one part of the sky in search of transiting planets within a 115 square degrees of the sky around the Cygnus, Lyra, and Draco constellations. After that, the satellite continued operating until 15 November 2018, this time changing its field along the ecliptic to a new area roughly every 75 days due to reaction wheel failure. |
Photocatalysis Heterogeneous photocatalysis Photocatalysis > Types of photocatalysis > Heterogeneous photocatalysis The ultimate goal of photocatalyst design is to facilitate reactions of the excited electrons with oxidants to produce reduced products, and/or reactions of the generated holes with reductants to produce oxidized products. Due to the generation of positive holes (h+) and excited electrons (e-), oxidation-reduction reactions take place at the surface of semiconductors irradiated with light. In one mechanism of the oxidative reaction, holes react with the moisture present on the surface and produce a hydroxyl radical. |
Apex of lung Examination Avian_lungs > Clinical significance > Examination As part of a physical examination in response to respiratory symptoms of shortness of breath, and cough, a lung examination may be carried out. This exam includes palpation and auscultation. The areas of the lungs that can be listened to using a stethoscope are called the lung fields, and these are the posterior, lateral, and anterior lung fields. The posterior fields can be listened to from the back and include: the lower lobes (taking up three quarters of the posterior fields); the anterior fields taking up the other quarter; and the lateral fields under the axillae, the left axilla for the lingual, the right axilla for the middle right lobe. |
Noble gas compound Applications Noble_gas_compounds > Applications Most applications of noble gas compounds are either as oxidising agents or as a means to store noble gases in a dense form. Xenic acid is a valuable oxidising agent because it has no potential for introducing impurities—xenon is simply liberated as a gas—and so is rivalled only by ozone in this regard. The perxenates are even more powerful oxidizing agents. Xenon-based oxidants have also been used for synthesizing carbocations stable at room temperature, in SO2ClF solution.Stable salts of xenon containing very high proportions of fluorine by weight (such as tetrafluoroammonium heptafluoroxenate(VI), , and the related tetrafluoroammonium octafluoroxenate(VI) 2), have been developed as highly energetic oxidisers for use as propellants in rocketry. |
Numerical-value equation Percentages, derivatives and integrals Numerical-value_equation > Concrete numbers and base units > Percentages, derivatives and integrals Percentages are dimensionless quantities, since they are ratios of two quantities with the same dimensions. In other words, the % sign can be read as "hundredths", since 1% = 1/100. Taking a derivative with respect to a quantity divides the dimension by the dimension of the variable that is differentiated with respect to. |
Slowly varying function Uniformity of the limiting behaviour Slowly_varying_function > Basic properties > Uniformity of the limiting behaviour Theorem 1. The limit in definitions 1 and 2 is uniform if a is restricted to a compact interval. |
Clamp or split-muff Balance Elastic_coupling > Balance Couplings are normally balanced at the factory prior to being shipped, but they occasionally go out of balance in operation. Balancing can be difficult and expensive, and is normally done only when operating tolerances are such that the effort and the expense are justified. The amount of coupling unbalance that can be tolerated by any system is dictated by the characteristics of the specific connected machines and can be determined by detailed analysis or experience. |
Usability engineering Summary Usability_engineering Rather than focusing on finding solutions for usability problems—which is the focus of a UX or interaction designer—a usability engineer mainly concentrates on the research phase. In this sense, it is not strictly a design role, and many usability engineers have a background in computer science because of this. Despite this point, its connection to the design trade is absolutely crucial, not least as it delivers the framework by which designers can work so as to be sure that their products will connect properly with their target usership. |
Stromgren sphere The physics Stromgren_sphere > The physics Very hot stars of the spectral class O or B emit very energetic radiation, especially ultraviolet radiation, which is able to ionize the neutral hydrogen (H I) of the surrounding interstellar medium, so that hydrogen atoms lose their single electrons. This state of hydrogen is called H II. After a while, free electrons recombine with those hydrogen ions. |
Sulfoxide Structure and bonding Sulfoxide > Structure and bonding The double-bond resonance form implies 10 electrons around sulfur (10-S-3 in N-X-L notation). The double-bond character of the S−O bond may be accounted for by donation of electron density into C−S antibonding orbitals ("no-bond" resonance forms in valence-bond language). Nevertheless, due to its simplicity and lack of ambiguity, the IUPAC recommends use of the expanded octet double-bond structure to depict sulfoxides, rather than the dipolar structure or structures that invoke "no-bond" resonance contributors. The S–O interaction has an electrostatic aspect, resulting in significant dipolar character, with negative charge centered on oxygen. |
Language construct Examples of language constructs Language_construct > Examples of language constructs In PHP print is a language construct. is the same as: In Java a class is written in this format: In C++ a class is written in this format: == References == |
Catalyst Science Discovery Centre Facilities Catalyst_Science_Discovery_Centre > Facilities Family workshops are arranged during school and bank holidays and there is a cafe.The exhibits range from test tubes to a 20-ton cast iron caustic soda finishing vessel, laboratory equipment, and chemical samples. The industrial focus of the collection is the salt-based chemical industries of Merseyside, South Lancashire, North Cheshire and Mid Cheshire, other chemical industries in these areas are also covered. Catalyst has collected local social history objects which has helped to give a human context to the collection. |
Phonological loop Logie's elaboration of the visuospatial sketchpad Phonological_loop > Components > Visuo-spatial working memory > Logie's elaboration of the visuospatial sketchpad Logie has proposed that the visuo-spatial sketchpad can be further subdivided into two components: The visual cache, which stores information about form and color. The inner scribe, which deals with spatial and movement information. It also rehearses information in the visual cache and transfers information to the central executive.Three main findings provide evidence for the distinction between visual and spatial parts of the visuospatial sketchpad: There is less interference between visual and spatial tasks than between two visual tasks or two spatial tasks. Brain damage can influence one of the components without influencing the other. Results from brain-imaging show that working memory tasks with visual objects activate mostly areas in the left hemisphere, whereas tasks with spatial information activate more areas in the right hemisphere. |
Cyanate ion Cyanate ion Cyanate > Cyanate ion The three atoms in a cyanate ion lie on a straight line, giving the ion a linear structure. The electronic structure is described most simply as :Ö̤−C≡N:with a single C−O bond and a triple C≡N bond. (Or more completely as :Ö̤−C≡N: ↔ Ö̤=C=N̤̈ ↔ :O≡C−N̤̈:) The infrared spectrum of a cyanate salt has a band at ca. |
History of speciation Summary History_of_speciation Debate over classification schemes on the mechanisms of speciation and reproductive isolation continue. The 21st century has seen a resurgence in the study of speciation, with new techniques such as molecular phylogenetics and systematics. Speciation has largely been divided into discrete modes that correspond to rates of gene flow between two incipient populations. Current research has driven the development of alternative schemes and the discovery of new processes of speciation. |
Substantia nigra Clinical significance Substantia_nigra > Clinical significance The substantia nigra is critical in the development of many diseases and syndromes, including parkinsonism and Parkinson's disease. There exist a study showing that high-frequency stimulation delivery to the left substantia nigra can induce transient acute depression symptoms. |
Broad-spectrum antibiotics Bacterial targets Broad-spectrum_antibiotics > Bacterial targets Antibiotics are often grouped by their ability to act on different bacterial groups. Although bacteria are biologically classified using taxonomy, disease-causing bacteria have historically been classified by their microscopic appearance and chemical function. The morphology of the organism may be classified as cocci, diplococci, bacilli (also known as "rods"), spiral-shaped or pleomorphic. Additional classification occurs through the organism's ability to take up the Gram stain and counter-stain; bacteria that take up the crystal violet dye stain are referred to as "gram-positive," those that take up the counterstain only are "gram-negative," and those that remain unstained are referred to as "atypical." |
Mucosal immunity Mucosal vaccines Mucosal_immunology > Mucosal vaccines Because of its front-line status within the immune system, the mucosal immune system is being investigated for use in vaccines for various afflictions, including COVID-19, HIV, allergies, poliovirus, influenza A and B, rotavirus, vibrio cholerae and many others. |
Out-of-kilter algorithm Summary Out-of-kilter_algorithm The out-of-kilter algorithm is an algorithm that computes the solution to the minimum-cost flow problem in a flow network. It was published in 1961 by D. R. Fulkerson and is described here. The analog of steady state flow in a network of nodes and arcs may describe a variety of processes. |
Orbit (celestial mechanics) Kepler's laws Orbit_raising > Newton's laws of motion > Kepler's laws The point on the orbit closest to the attracting body is the periapsis. The point farthest from the attracting body is called the apoapsis. There are also specific terms for orbits about particular bodies; things orbiting the Sun have a perihelion and aphelion, things orbiting the Earth have a perigee and apogee, and things orbiting the Moon have a perilune and apolune (or periselene and aposelene respectively). |
Biological patents Summary Patenting_genes A biological patent is a patent on an invention in the field of biology that by law allows the patent holder to exclude others from making, using, selling, or importing the protected invention for a limited period of time. The scope and reach of biological patents vary among jurisdictions, and may include biological technology and products, genetically modified organisms and genetic material. The applicability of patents to substances and processes wholly or partially natural in origin is a subject of debate. |
HIV envelope gp120 HIV_envelope > In HIV > gp120 The presence of a co-receptor, CXCR4, is sufficient for this mutant strain to infect human cells. The strain with this phenotype was found to have seven mutations in the sequence coding for gp120 and it is proposed that these mutations induce conformational changes in gp120 that allow the virus to directly interact with the co-receptor.Since CD4 receptor binding is the most obvious step in HIV infection, gp120 was among the first targets of HIV vaccine research. These efforts have been hampered by the fusion mechanism used by HIV, which makes neutralization by antibodies extremely difficult. Prior to binding the host cell, gp120 remains effectively hidden from antibodies because it is buried in the protein and shielded by sugars. Gp120 is only exposed when in close proximity to a host cell and the space between the viral and host cell membranes is small enough to sterically hinder the binding of antibodies. |
Memory address Physical addresses Memory_addressing > Types > Physical addresses A digital computer's main memory consists of many memory locations. Each memory location has a physical address which is a code. The CPU (or other device) can use the code to access the corresponding memory location. Generally only system software, i.e. the BIOS, operating systems, and some specialized utility programs (e.g., memory testers), address physical memory using machine code operands or processor registers, instructing the CPU to direct a hardware device, called the memory controller, to use the memory bus or system bus, or separate control, address and data busses, to execute the program's commands. The memory controllers' bus consists of a number of parallel lines, each represented by a binary digit (bit). The width of the bus, and thus the number of addressable storage units, and the number of bits in each unit, varies among computers. |
Statistical model selection Two directions of model selection Statistical_model_selection > Two directions of model selection For this goal, it is significantly important that the selected model is not too sensitive to the sample size. Accordingly, an appropriate notion for evaluating model selection is the selection consistency, meaning that the most robust candidate will be consistently selected given sufficiently many data samples. The second direction is to choose a model as machinery to offer excellent predictive performance. |
Vision Pro Development Vision_Pro > History > Development According to leaker Wayne Ma, Apple was originally going to allow macOS software to be dragged from the display to the user's environment, but was scrapped early on due to the limitations of being based on iOS, and noted that the hand-tracking system was not precise enough to game. Workers also discussed collaborations with brands such as Nike for working out with the headset, while others investigated face cushions that were better suited for sweaty, high-intensity workouts, but was scrapped due to the battery pack and the fragile screen. A feature called "co-presence", a projection of a FaceTime user's full body was also scrapped due to unknown reasons. |
VS ribozyme Hypothesis For Evolution of VS Ribozyme VS_ribozyme > Hypothesis For Evolution of VS Ribozyme RNA mediated cleavage and ligation is found in group 1 and group 2 self-splicing RNAs. VS RNA contains many conserved sequence characteristics to group 1 introns. However VS ribozyme splice site is different from group 1 intron splice site and VR ribozyme self-cleaving site is outside of the core of the group 1 intron. In the cleavage reaction VS ribozyme produce 2’,3’ -cyclic phosphate and the group 1 introns produce 3’-hydroxyl. Functional similarity with group 1 introns and then mechanistically being different from the introns support this hypothesis that VS ribozyme is a chimera formed by insertion of a novel catalytic RNA into group 1 introns. |
Division by zero Abstract algebra Division_by_zero > Higher mathematics > Abstract algebra In a field, every nonzero element is invertible under multiplication; as above, division poses problems only when attempting to divide by zero. This is likewise true in a skew field (which for this reason is called a division ring). |
Quartic equation Approximate methods Quartic_equation > Alternative methods > Approximate methods The methods described above are, in principle, exact root-finding methods. It is also possible to use successive approximation methods which iteratively converge towards the roots, such as the Durand–Kerner method. Iterative methods are the only ones available for quintic and higher-order equations, beyond trivial or special cases. |
Transversality (mathematics) Smoothness of solution spaces Transversality_(mathematics) > Applications > Smoothness of solution spaces An extremely special case of this is the following: if a differentiable function from reals to the reals has nonzero derivative at a zero of the function, then the zero is simple, i.e. it the graph is transverse to the x-axis at that zero; a zero derivative would mean a horizontal tangent to the curve, which would agree with the tangent space to the x-axis. For an infinite-dimensional example, the d-bar operator is a section of a certain Banach space bundle over the space of maps from a Riemann surface into an almost-complex manifold. The zero set of this section consists of holomorphic maps. |
Lymphocytic choriomeningitis Signs and symptoms Lymphocytic_choriomeningitis_virus > Signs and symptoms Meningoencephalitis is characterized by more profound neurological signs such as confusion, drowsiness, sensory abnormalities and motor signs. Under reported complications include myelitis, Guillain–Barré-type syndrome, cranial nerve palsies, transient or permanent hydrocephalus, sensorineural hearing loss, orchitis, arthritis and parotitis. LCMV infections have also been associated with pancreatitis, pneumonitis, myocarditis and pericarditis. The entire illness usually lasts 1 to 3 weeks, nonetheless, temporary or permanent neurological damage is possible in all central nervous system infections, especially in cases of meningoencephalitis. Chronic infections have not been reported in humans and deaths rarely occur. |
Pythagorean triple Descartes' Circle Theorem Pythagorean_triples > Special cases and related equations > Descartes' Circle Theorem For the case of Descartes' circle theorem where all variables are squares, 2 ( a 4 + b 4 + c 4 + d 4 ) = ( a 2 + b 2 + c 2 + d 2 ) 2 {\displaystyle 2(a^{4}+b^{4}+c^{4}+d^{4})=(a^{2}+b^{2}+c^{2}+d^{2})^{2}} Euler showed this is equivalent to three simultaneous Pythagorean triples, ( 2 a b ) 2 + ( 2 c d ) 2 = ( a 2 + b 2 − c 2 − d 2 ) 2 {\displaystyle (2ab)^{2}+(2cd)^{2}=(a^{2}+b^{2}-c^{2}-d^{2})^{2}} ( 2 a c ) 2 + ( 2 b d ) 2 = ( a 2 − b 2 + c 2 − d 2 ) 2 {\displaystyle (2ac)^{2}+(2bd)^{2}=(a^{2}-b^{2}+c^{2}-d^{2})^{2}} ( 2 a d ) 2 + ( 2 b c ) 2 = ( a 2 − b 2 − c 2 + d 2 ) 2 {\displaystyle (2ad)^{2}+(2bc)^{2}=(a^{2}-b^{2}-c^{2}+d^{2})^{2}} There is also an infinite number of solutions, and for the special case when a + b = c {\displaystyle a+b=c} , then the equation simplifies to, 4 ( a 2 + a b + b 2 ) = d 2 {\displaystyle 4(a^{2}+ab+b^{2})=d^{2}} with small solutions as a , b , c , d = 3 , 5 , 8 , 14 {\displaystyle a,b,c,d=3,5,8,14} and can be solved as binary quadratic forms. |
Memory cache Latency Hardware_cache > Motivation > Latency A larger resource incurs a significant latency for access – e.g. it can take hundreds of clock cycles for a modern 4 GHz processor to reach DRAM. This is mitigated by reading in large chunks, in the hope that subsequent reads will be from nearby locations. Prediction or explicit prefetching might also guess where future reads will come from and make requests ahead of time; if done correctly the latency is bypassed altogether. |
Universal enveloping algebra Casimir operators Universal_enveloping_algebra > Casimir operators {\displaystyle U({\mathfrak {g}}).} From the PBW theorem, it is clear that all central elements are linear combinations of symmetric homogenous polynomials in the basis elements e a {\displaystyle e_{a}} of the Lie algebra. The Casimir invariants are the irreducible homogenous polynomials of a given, fixed degree. |
Kapitza–Dirac effect Explanation Kapitsa–Dirac_effect > Explanation This matter wave diffraction is analogous to optical diffraction of light through a diffraction grating. Another incidence of this effect is the diffraction of ultra-cold (and therefore almost stationary) atoms by an optical lattice that is pulsed on for a very short duration. The application of an optical lattice transfers momentum from the photons creating the optical lattice onto the atoms. |
Canonical representation of a positive integer History Fundamental_Theorem_of_Arithmetic > History Any composite number is measured by some prime number. (In modern terminology: every integer greater than one is divided evenly by some prime number.) Proposition 31 is proved directly by infinite descent. |
Tau proteins Prion-like propagation hypothesis Tau_protein > Clinical significance > Prion-like propagation hypothesis Since tau has yet to be proven to be infectious it is not considered to be a true prion but instead a "prion-like" protein. Much like true prions, pathological tau aggregates have been shown to have the capacity to induce misfolding of native tau protein. Both misfolding competent and non-misfolding competent species of tau aggregates have been reported, indicating a highly specific mechanism. |
Numerical-value equation Formulation Numerical-value_equation > Formulation The Buckingham π theorem describes how every physically meaningful equation involving n variables can be equivalently rewritten as an equation of n − m dimensionless parameters, where m is the rank of the dimensional matrix. Furthermore, and most importantly, it provides a method for computing these dimensionless parameters from the given variables. A dimensional equation can have the dimensions reduced or eliminated through nondimensionalization, which begins with dimensional analysis, and involves scaling quantities by characteristic units of a system or natural units of nature. : 43 This may give insight into the fundamental properties of the system, as illustrated in the examples below. |
Modulation doping Field effect transistors Modulation_doping > Applications > Field effect transistors Modulation-doped transistors can reach high electrical mobilities and therefore fast operation. A modulation-doped field-effect transistor is known as a MODFET. |
Bloch sphere Definition Bloch_sphere > Definition For mixed states, one considers the density operator. Any two-dimensional density operator ρ can be expanded using the identity I and the Hermitian, traceless Pauli matrices σ → {\displaystyle {\vec {\sigma }}} , ρ = 1 2 ( I + a → ⋅ σ → ) = 1 2 ( 1 0 0 1 ) + a x 2 ( 0 1 1 0 ) + a y 2 ( 0 − i i 0 ) + a z 2 ( 1 0 0 − 1 ) = 1 2 ( 1 + a z a x − i a y a x + i a y 1 − a z ) {\displaystyle {\begin{aligned}\rho &={\frac {1}{2}}\left(I+{\vec {a}}\cdot {\vec {\sigma }}\right)\\&={\frac {1}{2}}{\begin{pmatrix}1&0\\0&1\end{pmatrix}}+{\frac {a_{x}}{2}}{\begin{pmatrix}0&1\\1&0\end{pmatrix}}+{\frac {a_{y}}{2}}{\begin{pmatrix}0&-i\\i&0\end{pmatrix}}+{\frac {a_{z}}{2}}{\begin{pmatrix}1&0\\0&-1\end{pmatrix}}\\&={\frac {1}{2}}{\begin{pmatrix}1+a_{z}&a_{x}-ia_{y}\\a_{x}+ia_{y}&1-a_{z}\end{pmatrix}}\end{aligned}}} ,where a → ∈ R 3 {\displaystyle {\vec {a}}\in \mathbb {R} ^{3}} is called the Bloch vector. It is this vector that indicates the point within the sphere that corresponds to a given mixed state. |
Vitamin K reaction Background Vitamin_K_reaction > Background In 1929, Henrik Dam discovered Vitamin K, also known as phylloquinone, phytonadione, or phytomenadione, which is a fat-soluble vitamin. Vitamin K is a family of structures of the aforementioned molecules and is not a single compound. Phytonadione, also known as K1, is synthetically derived, approved by the Food and Drug Administration (FDA) and is available on the market. It is available in many different formulations such as intravenous (IV) route, subcutaneous (SQ) route, intramuscular (IM) route and oral tablet. |
Glycolipid Glycosyltransferases Glycolipid > Metabolism > Glycosyltransferases Enzymes called glycosyltransferases link the saccharide to the lipid molecule, and also play a role in assembling the correct oligosaccharide so that the right receptor can be activated on the cell which responds to the presence of the glycolipid on the surface of the cell. The glycolipid is assembled in the Golgi apparatus and embedded in the surface of a vesicle which is then transported to the cell membrane. The vesicle merges with the cell membrane so that the glycolipid can be presented on the cell's outside surface. |
Disc filter Summary Disk_filter A disc filter is a type of water filter used primarily in irrigation, similar to a screen filter, except that the filter cartridge is made of a number of plastic discs stacked on top of each other like a pile of poker chips. Each disc is covered with small grooves or bumps. The discs (or rings) each have a hole in the middle, forming a hollow cylinder in the middle of the stack. |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.