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VM operating system History VM_operating_system > History The functions of the spool filesystem were also improved, allowing 9900 spool files to be created per user, rather than 9900 for the whole system. The architecture of the spool filesystem was also enhanced, each spool file now had a unique user ID associated with it, and reader file control blocks were now held in virtual storage. The system could also be configured to deny certain users access to the vector facility (by means of user directory entries).Releases of VM since VM/SP Release 1 supported multiprocessor systems.
Learning styles Learning modalities Learning_styles > Overview of models > Learning modalities Walter Burke Barbe and colleagues proposed three learning modalities (often identified by the acronym VAK): Visualizing modality Auditory modality Kinesthetic modalityBarbe and colleagues reported that learning modality strengths can occur independently or in combination (although the most frequent modality strengths, according to their research, are visual or mixed), they can change over time, and they become integrated with age. They also pointed out that learning modality strengths are different from preferences; a person's self-reported modality preference may not correspond to their empirically measured modality strength. : 378 This disconnect between strengths and preferences was confirmed by a subsequent study. Nevertheless, some scholars have criticized the VAK model. Psychologist Scott Lilienfeld and colleagues have argued that much use of the VAK model is nothing more than pseudoscience or a psychological urban legend.
Combinatorial enumeration Generating functions Enumerative_combinatorics > Generating functions The exponential generating function is also sometimes used. In this case it would have the form F ( x ) = ∑ n = 0 ∞ f n x n n ! {\displaystyle F(x)=\sum _{n=0}^{\infty }f_{n}{\frac {x^{n}}{n!}}} Once determined, the generating function yields the information given by the previous approaches. In addition, the various natural operations on generating functions such as addition, multiplication, differentiation, etc., have a combinatorial significance; this allows one to extend results from one combinatorial problem in order to solve others.
5 prime untranslated region Prokaryotes Leader_sequence_(mRNA) > Role in translational regulation > Prokaryotes Initiation in Archaea is less understood. SD sequences are much rarer, and the initiation factors have more in common with eukaryotic ones. There is no homolog of bacterial IF3. Some mRNAs are leaderless.In both domains, genes without Shine–Dalgarno sequences are also translated in a less understood manner. A requirement seems to be a lack of secondary structure near the initiation codon.
Glossary of genetics (M–Z) S Glossary_of_genetics_(M–Z) > S Compare null allele. silent mutation A type of neutral mutation which does not have an observable effect on the organism's phenotype. Though the term "silent mutation" is often used interchangeably with synonymous mutation, synonymous mutations are not always silent, nor vice versa.
Yen's algorithm Summary Yen's_algorithm In graph theory, Yen's algorithm computes single-source K-shortest loopless paths for a graph with non-negative edge cost. The algorithm was published by Jin Y. Yen in 1971 and employs any shortest path algorithm to find the best path, then proceeds to find K − 1 deviations of the best path.
Arc system Mechanism Arc_system > Mechanism ArcB is then able to activate or deactivate ArcA, the response regulator, which can then travel to the chromosome and regulate gene expression.ArcA is activated via phosphorylation. When oxygen is present in the cell ArcB autophosphorylates. This inorganic phosphate is then transferred via a four amino acid phosphorelay to ArcA.
Demographic transition Stage five Demographic_transition_model > Stages > Stage five The global data no longer support the suggestion that fertility rates tend to broadly rise at very high levels of national development.From the point of view of evolutionary biology, wealthier people having fewer children is unexpected, as natural selection would be expected to favor individuals who are willing and able to convert plentiful resources into plentiful fertile descendants. This may be the result of a departure from the environment of evolutionary adaptedness.Most models posit that the birth rate will stabilize at a low level indefinitely. Some dissenting scholars note that the modern environment is exerting evolutionary pressure for higher fertility, and that eventually due to individual natural selection or cultural selection, birth rates may rise again. Part of the "cultural selection" hypothesis is that the variance in birth rate between cultures is significant; for example, some religious cultures have a higher birth rate that isn't accounted for by differences in income.Jane Falkingham of Southampton University has noted that "We've actually got population projections wrong consistently over the last 50 years… we've underestimated the improvements in mortality… but also we've not been very good at spotting the trends in fertility." In 2004 a United Nations office published its guesses for global population in the year 2300; estimates ranged from a "low estimate" of 2.3 billion (tending to −0.32% per year) to a "high estimate" of 36.4 billion (tending to +0.54% per year), which were contrasted with a deliberately "unrealistic" illustrative "constant fertility" scenario of 134 trillion (obtained if 1995–2000 fertility rates stay constant into the far future).
K-regular sequence History K-regular_sequence > History The notion of k-regular sequences was first investigated in a pair of papers by Allouche and Shallit. Prior to this, Berstel and Reutenauer studied the theory of rational series, which is closely related to k-regular sequences.
Spectral theory Resolution of the identity Spectral_theory > Resolution of the identity Using the bra–ket notation of the above section, the identity operator may be written as: I = ∑ i = 1 n \| e i ⟩ ⟨ f i \| {\displaystyle I=\sum _{i=1}^{n}\|e_{i}\rangle \langle f_{i}\|} where it is supposed as above that { \| e i ⟩ } {\displaystyle \{\|e_{i}\rangle \}} are a basis and the { ⟨ f i \| } {\displaystyle \{\langle f_{i}\|\}} a reciprocal basis for the space satisfying the relation: ⟨ f i \| e j ⟩ = δ i j . {\displaystyle \langle f_{i}\|e_{j}\rangle =\delta _{ij}.} This expression of the identity operation is called a representation or a resolution of the identity.
Atomic model (mathematical logic) Properties Atomic_model_(mathematical_logic) > Properties The back-and-forth method can be used to show that any two countable atomic models of a theory that are elementarily equivalent are isomorphic.
Television standards conversion Phase correlation Television_standards_conversion > Standards conversion methods in common use > Phase correlation Phase correlation is elegant as well as technically and conceptually complex. Its successful operation is derived by performing a Fourier transform to each field of video. A fast Fourier transform (FFT) is an algorithm which deals with the transformation of discrete values (in this case image pixels). When applied to a sample of finite values, a fast Fourier transform expresses any changes (motion) in terms of frequency components. Since the result of the FFT represents only the inter-frame changes in terms of frequency distribution, there is far less data that has to be processed in order to calculate the motion vectors.
Assistive Technology Industry Association Summary Assistive_Technology_Industry_Association In 2009, ATIA began providing educational online webinars to serve these groups. ATIA has also held conferences in collaboration with the Job Accommodation Network and United States Business Leadership Network (USBLN). The published result of one such conference is Roadmaps for Enhancing Employment of Persons with Disabilities through Accessible Technology.
Distributed file system for cloud Economic aspects Distributed_file_system_for_cloud > Economic aspects The cloud computing economy is growing rapidly. The US government has decided to spend 40% of its compound annual growth rate (CAGR), expected to be 7 billion dollars by 2015.More and more companies have been utilizing cloud computing to manage the massive amount of data and to overcome the lack of storage capacity, and because it enables them to use such resources as a service, ensuring that their computing needs will be met without having to invest in infrastructure (Pay-as-you-go model).Every application provider has to periodically pay the cost of each server where replicas of data are stored. The cost of a server is determined by the quality of the hardware, the storage capacities, and its query-processing and communication overhead. Cloud computing allows providers to scale their services according to client demands.
Coxsackie B virus Symptoms Coxsackie_B_virus > Symptoms Patients with chest pain should see a doctor immediately—in some cases, viruses in the Coxsackie B family progress to myocarditis or pericarditis, which can result in permanent heart damage or death. Coxsackie B virus infection may also induce aseptic meningitis. As a group, they are the most common cause of unexpected sudden death, and may account for up to 50% of such cases.
Matrix (composite) Functions Matrix_(composite) > Functions A matrix serves the following functions: It binds the fiber reinforcement. It provides the composite component its shape and directs its surface quality.
Vascular endothelial cells Function Endothelial_cells > Function The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. This forms a barrier between vessels and tissues and control the flow of substances and fluid into and out of a tissue. This controls the passage of materials and the transit of white blood cells into and out of the bloodstream. Excessive or prolonged increases in permeability of the endothelium, as in cases of chronic inflammation, may lead to tissue swelling (edema).
Unbalanced line Planar technologies Unbalanced_line > Planar technologies Planar format transmission lines are flat conductors manufactured by a number of techniques on to a substrate. They are nearly always an unbalanced format. At the low transmission speeds of early telegraph it was only necessary to consider transmission line theory for a circuit design when the transmission was over many miles. Similarly, the audio frequencies used by telephones are relatively low and transmission line theory only becomes significant for distances of at least between buildings.
Categories for the Working Mathematician Summary Categories_for_the_Working_Mathematician Categories for the Working Mathematician (CWM) is a textbook in category theory written by American mathematician Saunders Mac Lane, who cofounded the subject together with Samuel Eilenberg. It was first published in 1971, and is based on his lectures on the subject given at the University of Chicago, the Australian National University, Bowdoin College, and Tulane University. It is widely regarded as the premier introduction to the subject.
Vitamin B9 Anti-folate chemotherapy Folic_acid > Health effects > Cancer > Anti-folate chemotherapy Bone marrow depression (inducing leukopenia and thrombocytopenia) and acute kidney and liver failure have been reported. Folinic acid, under the drug name leucovorin, a form of folate (formyl-THF), can help "rescue" or reverse the toxic effects of methotrexate. Folic acid supplements have little established role in cancer chemotherapy. The supplement of folinic acid in people undergoing methotrexate treatment is to give less rapidly dividing cells enough folate to maintain normal cell functions. The amount of folate given is quickly depleted by rapidly dividing (cancer) cells, so this does not negate the effects of methotrexate.
Industrial Robot Defining parameters Robotic_axe > Technical description > Defining parameters When the absolute position of the robot is measured and compared to the commanded position the error is a measure of accuracy. Accuracy can be improved with external sensing for example a vision system or Infra-Red. See robot calibration.
False negatives Ambiguity in the definition of false positive rate True_negative > Related terms > Ambiguity in the definition of false positive rate The false positive risk is always higher, often much higher, than the p-value.Confusion of these two ideas, the error of the transposed conditional, has caused much mischief. Because of the ambiguity of notation in this field, it is essential to look at the definition in every paper. The hazards of reliance on p-values was emphasized in Colquhoun (2017) by pointing out that even an observation of p = 0.001 was not necessarily strong evidence against the null hypothesis.
Time integration methods Methods Exponential_Euler_method > Methods Explicit examples from the linear multistep family include the Adams–Bashforth methods, and any Runge–Kutta method with a lower diagonal Butcher tableau is explicit. A loose rule of thumb dictates that stiff differential equations require the use of implicit schemes, whereas non-stiff problems can be solved more efficiently with explicit schemes. The so-called general linear methods (GLMs) are a generalization of the above two large classes of methods.
Glossary of Lie groups and Lie algebras G Glossary_of_Lie_groups_and_Lie_algebras > G 3. For "Generalized Verma module", see #Verma. group Group analysis of differential equations.
Human digestive system Stomach Human_digestive_system > Components > Stomach Pepsinogen is a precursor enzyme (zymogen) produced by the gastric chief cells, and gastric acid activates this to the enzyme pepsin which begins the digestion of proteins. As these two chemicals would damage the stomach wall, mucus is secreted by innumerable gastric glands in the stomach, to provide a slimy protective layer against the damaging effects of the chemicals on the inner layers of the stomach. At the same time that protein is being digested, mechanical churning occurs through the action of peristalsis, waves of muscular contractions that move along the stomach wall.
Potential difference Circuit theory Potential_difference > Definition > Circuit theory In circuit analysis and electrical engineering, lumped element models are used to represent and analyze circuits. These elements are idealized and self-contained circuit elements used to model physical components.When using a lumped element model, it is assumed that the effects of changing magnetic fields produced by the circuit are suitably contained to each element. Under these assumptions, the electric field in the region exterior to each component is conservative, and voltages between nodes in the circuit are well-defined, where Δ V A B = − ∫ r A r B E ⋅ d ℓ {\displaystyle \Delta V_{AB}=-\int _{\mathbf {r} _{A}}^{\mathbf {r} _{B}}\mathbf {E} \cdot \mathrm {d} {\boldsymbol {\ell }}} as long as the path of integration does not pass through the inside of any component. The above is the same formula used in electrostatics.
Castration-resistant prostate cancer Staging Castration-resistant_prostate_cancer > Diagnosis > Staging N1 represents any spread to the nearby lymph nodes. M1 represents any metastases to other body sites.The AJCC then combines the TNM scores, Gleason grade group, and results of the PSA blood test to categorize cancer cases into one of four stages, and their subdivisions. Cancer cases with localized tumors (T1 or T2), no spread (N0 and M0), Gleason grade group 1, and PSA less than 10 ng/mL are designated stage I. Those with localized tumors and PSA between 10 and 20 ng/mL are desigated stage II – subdivided into IIA for Gleason grade group 1, IIB for grade group 2, and IIC for grade group 3 or 4.
Duhamel's principle Constant-coefficient linear ODE Duhamel's_principle > Examples > Constant-coefficient linear ODE All steps are done formally, ignoring necessary requirements for the solution to be well defined. First let G solve Define H = G χ [ 0 , ∞ ) {\displaystyle H=G\chi _{[0,\infty )}} , with χ [ 0 , ∞ ) {\displaystyle \chi _{[0,\infty )}} being the characteristic function of the interval [ 0 , ∞ ) {\displaystyle [0,\infty )} . Then we have in the sense of distributions. Therefore solves the ODE.
Dynamical symmetry breaking Dynamical symmetry breaking Dynamical_symmetry_breaking > In particle physics > Dynamical symmetry breaking (Such models, in which a composite particle plays the role of the Higgs boson, are often referred to as "Composite Higgs models".) Dynamical breaking of gauge symmetries is often due to creation of a fermionic condensate — e.g., the quark condensate, which is connected to the dynamical breaking of chiral symmetry in quantum chromodynamics. Conventional superconductivity is the paradigmatic example from the condensed matter side, where phonon-mediated attractions lead electrons to become bound in pairs and then condense, thereby breaking the electromagnetic gauge symmetry.
Reducer (chemistry) Examples of redox reaction Reducing_agents > Examples of redox reaction The rate of production of oxygen eventually exceeded the availability of reducing materials that removed oxygen, which ultimately led Earth to gain a strongly oxidizing atmosphere containing abundant oxygen (like the modern atmosphere). The modern sense of donating electrons is a generalization of this idea, acknowledging that other components can play a similar chemical role to oxygen. The formation of iron(III) oxide; 4Fe + 3O2 → 4Fe3+ + 6O2− → 2Fe2O3In the above equation, the Iron (Fe) has an oxidation number of 0 before and 3+ after the reaction.
Quantum mutual information Motivation Quantum_mutual_information > Motivation For simplicity, it will be assumed that all objects in the article are finite-dimensional. The definition of quantum mutual entropy is motivated by the classical case. For a probability distribution of two variables p(x, y), the two marginal distributions are p ( x ) = ∑ y p ( x , y ) , p ( y ) = ∑ x p ( x , y ) . {\displaystyle p(x)=\sum _{y}p(x,y),\qquad p(y)=\sum _{x}p(x,y).}
Common Intermediate Language Computational model Common_Intermediate_Language > Computational model The Common Intermediate Language is object-oriented and stack-based, which means that instruction parameters and results are kept on a single stack instead of in several registers or other memory locations, as in most programming languages. Code that adds two numbers in x86 assembly language, where eax and edx specify two different general-purpose registers: Code in an intermediate language (IL), where 0 is eax and 1 is edx: In the latter example, the values of the two registers, eax and edx, are first pushed on the stack. When the add-instruction is called the operands are "popped", or retrieved, and the result is "pushed", or stored, on the stack. The resulting value is then popped from the stack and stored in eax.
Microtubule-associated protein Other MAPs and Naming Issues Microtubule-associated_protein > Types > Other MAPs and Naming Issues During mitosis the dynamic instability of microtubules has been observed to rise approximately tenfold. This is partly due to phosphorylation of XMAP215, which makes catastrophes (rapid depolymerization of microtubules) more likely. In this way the phosphorylation of MAPs plays a role in mitosis.
Synthetic organic chemistry Characterization Organic_Chemistry > Characterization The principal constituent atoms of organic chemistry – hydrogen and carbon – exist naturally with NMR-responsive isotopes, respectively 1H and 13C. Elemental analysis: A destructive method used to determine the elemental composition of a molecule. See also mass spectrometry, below.
Biochemistry History Biochemical_Processes > History These techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle (citric acid cycle), and led to an understanding of biochemistry on a molecular level. Another significant historic event in biochemistry is the discovery of the gene, and its role in the transfer of information in the cell. In the 1950s, James D. Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins were instrumental in solving DNA structure and suggesting its relationship with the genetic transfer of information.
Information security Integrity Information_security_policies > Basic principles > Key concepts > Integrity Information security systems typically incorporate controls to ensure their own integrity, in particular protecting the kernel or core functions against both deliberate and accidental threats. Multi-purpose and multi-user computer systems aim to compartmentalize the data and processing such that no user or process can adversely impact another: the controls may not succeed however, as we see in incidents such as malware infections, hacks, data theft, fraud, and privacy breaches.More broadly, integrity is an information security principle that involves human/social, process, and commercial integrity, as well as data integrity. As such it touches on aspects such as credibility, consistency, truthfulness, completeness, accuracy, timeliness, and assurance.
Interference freedom Examples of formally proved concurrent programs Interference_freedom > Examples of formally proved concurrent programs In contrast, Rosen's article uses Findpos as the single, running example in this 24 page paper. An outline of both processes in a general environment: cobegin producer: ... await in-out < N then skip; add: b:= next value; markin: in:= in+1; ... // consumer: ... await in-out > 0 then skip; remove: this value:= b; markout: out:= out+1;coend... B. Bounded buffer consumer/producer problem. A producer process generates values and puts them into bounded buffer b of size N; a consumer process removes them.
List of finite element software packages Summary List_of_finite_element_software_packages This is a list of notable software packages that implement the finite element method for solving partial differential equations.
Geometric feature learning Evaluation framework Geometric_feature_learning > PAC model based feature learning algorithm > Evaluation framework support vector machinesThe main purpose of SVM is to find a hyperplane to separate the set of samples ( x i , y i ) {\displaystyle \textstyle (x_{i},y_{i})} where x i {\displaystyle \textstyle x_{i}} is an input vector which is a selection of features x ∈ R N {\displaystyle \textstyle x\in R^{N}} and y i {\displaystyle \textstyle y_{i}} is the label of x i {\displaystyle \textstyle x_{i}} . The hyperplane has the following form: f ( x ) = s g n ( ∑ i = 1 l y i α i ⋅ k ( x , x i ) + b ) = { 1 , p o s i t i v e i n p u t s − 1 , n e g a t i v e i n p u t s {\displaystyle \textstyle f(x)=sgn\left(\sum _{i=1}^{l}y_{i}\alpha _{i}\cdot k(x,x_{i})+b\right)=\left\{{\begin{matrix}1,positive\;inputs\\-1,negative\;inputs\end{matrix}}\right.} k ( x , x i ) = ϕ ( x ) ⋅ ϕ ( x i ) {\displaystyle \textstyle k(x,x_{i})=\phi (x)\cdot \phi (x_{i})} is a kernel function Both algorithms separate training data by finding a linear function.
Black-body radiation Summary Blackbody_radiation Black-body radiation is the thermal electromagnetic radiation within, or surrounding, a body in thermodynamic equilibrium with its environment, emitted by a black body (an idealized opaque, non-reflective body). It has a specific, continuous spectrum of wavelengths, inversely related to intensity, that depend only on the body's temperature, which is assumed, for the sake of calculations and theory, to be uniform and constant.A perfectly insulated enclosure which is in thermal equilibrium internally contains blackbody radiation, and will emit it through a hole made in its wall, provided the hole is small enough to have a negligible effect upon the equilibrium. The thermal radiation spontaneously emitted by many ordinary objects can be approximated as blackbody radiation. Of particular importance, although planets and stars (including the Earth and Sun) are neither in thermal equilibrium with their surroundings nor perfect black bodies, blackbody radiation is still a good first approximation for the energy they emit.
Cancer stem cell Summary Cancer_stem_cell In particular, in mice, whose life spans do not exceed two years, tumor relapse is difficult to study. The efficacy of cancer treatments is, in the initial stages of testing, often measured by the ablation fraction of tumor mass (fractional kill). As CSCs form a small proportion of the tumor, this may not necessarily select for drugs that act specifically on the stem cells.
Nucleophilic abstraction Alkyl abstraction Nucleophilic_abstraction > Alkyl abstraction There are several possibilities for the mechanism of this reaction which are shown in the following schematic. In path a, the first step proceeds with the oxidative addition of the halogen to the metal complex. This step results in the oxidized metal center that is needed to weaken the M-C bond.
Ohm metre Ideal case Electrically_conductive > Definition > Ideal case This is written as: where The resistivity can be expressed using the SI unit ohm metre (Ω⋅m) — i.e. ohms multiplied by square metres (for the cross-sectional area) then divided by metres (for the length). Both resistance and resistivity describe how difficult it is to make electrical current flow through a material, but unlike resistance, resistivity is an intrinsic property and does not depend on geometric properties of a material.
Order statistic tree Summary Order_statistic_tree In computer science, an order statistic tree is a variant of the binary search tree (or more generally, a B-tree) that supports two additional operations beyond insertion, lookup and deletion: Select(i) – find the i'th smallest element stored in the tree Rank(x) – find the rank of element x in the tree, i.e. its index in the sorted list of elements of the treeBoth operations can be performed in O(log n) worst case time when a self-balancing tree is used as the base data structure.
Human overpopulation History of world population Human_overpopulation > Overview > History of world population World population has gone through a number of periods of growth since the dawn of civilization in the Holocene period, around 10,000 BCE. The beginning of civilization roughly coincides with the receding of glacial ice following the end of the Last Glacial Period. Farming allowed for the growth of populations in many parts of the world, including Europe, the Americas and China through the 1600s, occasionally disrupted by plagues or other crises.
GNU Name System GNU Name System GNUnet > GNU Name System GNUnet includes an implementation of the GNU Name System (GNS), a decentralized and censorship-resistant replacement for DNS. In GNS, each user manages their own zones and can delegate subdomains to zones managed by other users. Lookups of records defined by other users are performed using GNUnet's DHT.
Archaeology of trade Agent-based modeling Archaeology_of_trade > Techniques > Agent-based modeling Agent-based modeling (ABM) is the simulation of agents (humans and social systems) based on a series of specified inputs. It models how humans (agents) and societies respond to inputs and stresses. For example, archaeologists working on social interactions in the Roman world used ABM to understand how social exchange affected the development of Roman expansionism in different regions. Elsewhere, archaeologists working on human subsistence mechanisms modeled how economics affected social complexity in Eastern North America.
History of biochemistry Enzymes History_of_biochemistry > Enzymes The word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment was used to refer to chemical activity produced by living organisms. In 1897 Eduard Buchner began to study the ability of yeast extracts to ferment sugar despite the absence of living yeast cells. In a series of experiments at the University of Berlin, he found that the sugar was fermented even when there were no living yeast cells in the mixture.
Gear oil API ratings Gear_oil > API ratings Friction modifiers and extreme pressure additives shall not be used. API Category GL-2 (inactive) designates the type of service characteristic of automotive type worm-gear axles operating under such conditions of load, temperature and sliding velocities, that lubricants satisfactory for API GL-1 service will not suffice. API Category GL-3 (inactive) designates the type of service characteristic of manual transmissions and spiral-bevel axles operating under mild to moderate to severe conditions of speed and load.
Population viability analysis Summary Population_viability_analysis Population viability analysis (PVA) is a species-specific method of risk assessment frequently used in conservation biology. It is traditionally defined as the process that determines the probability that a population will go extinct within a given number of years. More recently, PVA has been described as a marriage of ecology and statistics that brings together species characteristics and environmental variability to forecast population health and extinction risk. Each PVA is individually developed for a target population or species, and consequently, each PVA is unique. The larger goal in mind when conducting a PVA is to ensure that the population of a species is self-sustaining over the long term.
Particle mechanics Quantum Particle_mechanics > Sub-disciplines > Quantum For example, following the ideas of Greek philosopher and scientist Aristotle, scientists reasoned that a cannonball falls down because its natural position is in the Earth; the Sun, the Moon, and the stars travel in circles around the Earth because it is the nature of heavenly objects to travel in perfect circles. Often cited as father to modern science, Galileo brought together the ideas of other great thinkers of his time and began to calculate motion in terms of distance travelled from some starting position and the time that it took. He showed that the speed of falling objects increases steadily during the time of their fall.
Tumor suppressor protein p53 Human TP53 gene P53_protein > Gene > Human TP53 gene In humans, a common polymorphism involves the substitution of an arginine for a proline at codon position 72 of exon 4. Many studies have investigated a genetic link between this variation and cancer susceptibility; however, the results have been controversial. For instance, a meta-analysis from 2009 failed to show a link for cervical cancer. A 2011 study found that the TP53 proline mutation did have a profound effect on pancreatic cancer risk among males.
Named data networking Routing efficiency and security Named_data_networking > Security > Routing efficiency and security Furthermore, NDN treats network routing and control messages like all NDN data, requiring signatures. This provides a solid foundation for securing routing protocols against attack, e.g., spoofing and tampering. NDN's use of multipath forwarding, together with the adaptive forwarding strategy module, mitigates prefix hijacking because routers can detect anomalies caused by hijacks and retrieve data through alternate paths.
Sensory perception Process and terminology Human_perception > Process and terminology The process of perception begins with an object in the real world, known as the distal stimulus or distal object. By means of light, sound, or another physical process, the object stimulates the body's sensory organs. These sensory organs transform the input energy into neural activity—a process called transduction. This raw pattern of neural activity is called the proximal stimulus.
Group B streptococcus vaccine Adults Group_B_streptococcus_vaccine > Adults GBS is also an important infectious agent able to cause invasive infections in adults. Serious life-threatening invasive GBS infections are increasingly recognized in the elderly and in individuals compromised by underlying diseases such as diabetes, cirrhosis and cancer. GBS infections in adults include urinary tract infection, skin and soft-tissue infection (skin and skin structure infection) bacteremia without focus, osteomyelitis, meningitis and endocarditis. GBS infection in adults can be serious, and mortality is higher among adults than among neonates.In general, penicillin is the antibiotic of choice for treatment of GBS infections.
Thermodynamic arrow Cosmology Entropy_as_an_arrow_of_time > Current research > Cosmology In this scenario, the cosmological arrow of time is the reason for both the thermodynamic arrow of time and the quantum arrow of time. Both will slowly disappear as the universe will come to a halt, and will later be reversed.In the first and more consensual scenario, it is the difference between the initial state and the final state of the universe that is responsible for the thermodynamic arrow of time. This is independent of the cosmological arrow of time.
Naval architect Structures Naval_architecture > Main subjects > Structures The dimensions of the ship are in order to create enough spacing between the stiffeners in prevention of buckling. Warships have used a longitudinal system of stiffening that many modern commercial vessels have adopted. This system was widely used in early merchant ships such as the SS Great Eastern, but later shifted to transversely framed structure another concept in ship hull design that proved more practical.
Cohesive force Summary Cohesion_(chemistry) This results in a relatively strong Coulomb force between molecules. In simple terms, the polarity (a state in which a molecule is oppositely charged on its poles) of water molecules allows them to be attracted to each other. The polarity is due to the electronegativity of the atom of oxygen: oxygen is more electronegative than the atoms of hydrogen, so the electrons they share through the covalent bonds are more often close to oxygen rather than hydrogen.
Abaqus Summary Abaqus Abaqus FEA (formerly ABAQUS) is a software suite for finite element analysis and computer-aided engineering, originally released in 1978. The name and logo of this software are based on the abacus calculation tool. The Abaqus product suite consists of five core software products: Abaqus/CAE, or "Complete Abaqus Environment" (a backronym with a root in Computer-Aided Engineering). It is a software application used for both the modeling and analysis of mechanical components and assemblies (pre-processing) and visualizing the finite element analysis result.
Viral encephalitis Examination Viral_encephalitis > Diagnosis > Examination Severe symptoms are most common among infants and the elderly. Most infections are asymptomatic, lacking symptoms, whereas most symptomatic cases are mild illnesses.Virus-specific symptoms may also exist or tests may indicate one virus. Specific examples include: Enterovirus 71 may cause tremors, twitching, impaired balance and coordination, fluid accumulation in the lungs, and cranial nerve palsies.
Invariant (computer science) Invariants in computer science Invariant_(mathematics) > Invariants in computer science In computer science, an invariant is a logical assertion that is always held to be true during a certain phase of execution of a computer program. For example, a loop invariant is a condition that is true at the beginning and the end of every iteration of a loop. Invariants are especially useful when reasoning about the correctness of a computer program.
Z Transform Inverse Z-transform Z_Transform > Inverse Z-transform This contour can be used when the ROC includes the unit circle, which is always guaranteed when X ( z ) {\displaystyle X(z)} is stable, that is, when all the poles are inside the unit circle. With this contour, the inverse Z-transform simplifies to the inverse discrete-time Fourier transform, or Fourier series, of the periodic values of the Z-transform around the unit circle: The Z-transform with a finite range of n {\displaystyle n} and a finite number of uniformly spaced z {\displaystyle z} values can be computed efficiently via Bluestein's FFT algorithm. The discrete-time Fourier transform (DTFT)—not to be confused with the discrete Fourier transform (DFT)—is a special case of such a Z-transform obtained by restricting z {\displaystyle z} to lie on the unit circle.
Portable radio Spark era Radio_receiver > History > Spark era Most receivers used a pair of tuned circuits with their coils magnetically coupled, called a resonant transformer (oscillation transformer) or "loose coupler". A detector, which produced a pulse of DC current for each damped wave received. An indicating device such as an earphone, which converted the pulses of current into sound waves.
SeaTwirl Design SeaTwirl > Design SeaTwirl has a vertical axis, with blades above water and the generator below. It is one of several designs that can float and therefore be positioned far offshore and take advantage of the stronger winds there. The SeaTwirl design uses the seawater itself as a roller bearing and stores energy in a water-filled torus. The company intends to use the design to enable the use of cheaper and heavier materials to lower the cost below conventional turbines and generate energy even when the wind is not blowing.If the design is scaled to 430 m long, the company claims that it could provide 4.5 MW of electricity and store 25 MWh of energy.
Measurement Mass Measurement > Units and systems > Mass Mass refers to the intrinsic property of all material objects to resist changes in their momentum. Weight, on the other hand, refers to the downward force produced when a mass is in a gravitational field. In free fall, (no net gravitational forces) objects lack weight but retain their mass. The Imperial units of mass include the ounce, pound, and ton.
Navigation function Potential functions as navigation functions Navigation_function > Potential functions as navigation functions Potential functions assume that the environment or work space is known. Obstacles are assigned a high potential value, and the goal position is assigned a low potential. To reach the goal position, a robot only needs to follow the negative gradient of the surface.
Noether theorem Examples Noether_charge > Mathematical expression > Simple form using perturbations > Examples {\displaystyle \mathbf {Q} =\mathbf {n} \times \mathbf {r} .} Then Noether's theorem states that the following quantity is conserved, ∂ L ∂ q ˙ ⋅ Q = p ⋅ ( n × r ) = n ⋅ ( r × p ) = n ⋅ L . {\displaystyle {\frac {\partial L}{\partial {\dot {\mathbf {q} }}}}\cdot \mathbf {Q} =\mathbf {p} \cdot \left(\mathbf {n} \times \mathbf {r} \right)=\mathbf {n} \cdot \left(\mathbf {r} \times \mathbf {p} \right)=\mathbf {n} \cdot \mathbf {L} .} In other words, the component of the angular momentum L along the n axis is conserved. And if n is arbitrary, i.e., if the system is insensitive to any rotation, then every component of L is conserved; in short, angular momentum is conserved.
Convention (norm) Summary Convention_(norm) A convention is a set of agreed, stipulated, or generally accepted standards, social norms, or other criteria, often taking the form of a custom. In a social context, a convention may retain the character of an "unwritten law" of custom (for example, the manner in which people greet each other, such as by shaking each other's hands). Certain types of rules or customs may become law and sometimes they may be further codified to formalize or enforce the convention (for example, laws that define on which side of the road vehicles must be driven). In physical sciences, numerical values (such as constants, quantities, or scales of measurement) are called conventional if they do not represent a measured property of nature, but originate in a convention, for example an average of many measurements, agreed between the scientists working with these values.
Minor key Intonation and tuning Major_and_minor > Intonation and tuning Musical tuning of intervals is expressed by the ratio between the pitches' frequencies. Simple fractions can sound more harmonious than complex fractions; for instance, an octave is a simple 2:1 ratio and a fifth is the relatively simple 3:2 ratio. The table below gives approximations of a scale to ratios that are rounded to be as simple as possible. In just intonation, a minor chord is often (but not exclusively) tuned in the frequency ratio 10:12:15 ().
Inorganic chemical reaction Reactions at ligands Inorganic_chemical_reaction > Mechanistic inorganic chemistry > Transition metal complexes > Reactions at ligands Coordinated ligands display reactivity distinct from the free ligands. For example, the acidity of the ammonia ligands in 3+ is elevated relative to NH3 itself. Alkenes bound to metal cations are reactive toward nucleophiles whereas alkenes normally are not. The large and industrially important area of catalysis hinges on the ability of metals to modify the reactivity of organic ligands.
Nuclear gene Endosymbiotic organelle interactions Nuclear_gene > Endosymbiotic organelle interactions Though separated from one another within the cell, nuclear genes and those of mitochondria and chloroplasts can affect each other in a number of ways. Nuclear genes play major roles in the expression of chloroplast genes and mitochondrial genes. Additionally, gene products of mitochondria can themselves affect the expression of genes within the cell nucleus. This can be done through metabolites as well as through certain peptides trans-locating from the mitochondria to the nucleus, where they can then affect gene expression.
Active daylighting Types Passive_daylighting > Types Passive daylighting is a system of both collecting sunlight using static, non-moving, and non-tracking systems (such as windows, sliding glass doors, most skylights, light tubes) and reflecting the collected daylight deeper inside with elements such as light shelves. Passive daylighting systems are different from active daylighting systems in that active systems track and/or follow the sun, and rely on mechanical mechanisms to do so.
Byzantine fault Solutions Byzantine_agreement > Solutions A second solution requires unforgeable message signatures. For security-critical systems, digital signatures (in modern computer systems, this may be achieved in practice using public-key cryptography) can provide Byzantine fault tolerance in the presence of an arbitrary number of traitorous generals. However, for safety-critical systems (where "security" addresses intelligent threats while "safety" addresses the inherent dangers of an activity or mission), simple error detecting codes, such as CRCs, provide weaker but often sufficient coverage at a much lower cost.
Order of magnitude (numbers) 101 Order_of_magnitude_(numbers) > 101 (10; ten) ISO: deca- (da) Demography: The population of Pesnopoy, a village in Bulgaria, was 10 in 2007. Human scale: There are 10 digits on a pair of human hands, and 10 toes on a pair of human feet. Mathematics: The number system used in everyday life, the decimal system, has 10 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. Religion: the Ten Commandments in the Abrahamic religions.
Animal communication Autocommunication Animal_communication > Autocommunication The second type of autocommunication is echolocation, found in bats and toothed whales. Echolocation involves emitting sounds and interpreting the vibrations that return from objects. In bats, echolocation also serves the purpose of mapping their environment. They are capable of recognizing a space they've been in before without any visible light because they can memorize patterns in the feedback they get from echolocation.
Marine terrace Processes Raised_beach > Formation > Processes Marine terraces often result from marine erosion along rocky coastlines in temperate regions due to wave attack and sediment carried in the waves. Erosion also takes place in connection with weathering and cavitation. The speed of erosion is highly dependent on the shoreline material (hardness of rock), the bathymetry, and the bedrock properties and can be between only a few millimeters per year for granitic rocks and more than 10 metres (33 ft) per year for volcanic ejecta. The retreat of the sea cliff generates a shore (wave-cut/abrasion-) platform through the process of abrasion.
Gsx (gene family) Summary Gsx_(gene_family) The Gsx gene family are a group of genes found in many, but not all, animals. Gsx genes contain a homeobox DNA sequence and code for proteins that act as transcription factors. The human genome has two Gsx genes, called GSX1 and GSX2 (formerly GSH1 and GSH2), while the fruitfly Drosophila has a single Gsx gene called ind.
A New Kind of Science Computational irreducibility A_New_Kind_of_Science > Contents > Philosophical underpinnings > Computational irreducibility Wolfram argues that one of his achievements is in providing a coherent system of ideas that justifies computation as an organizing principle of science. For instance, he argues that the concept of computational irreducibility (that some complex computations are not amenable to short-cuts and cannot be "reduced"), is ultimately the reason why computational models of nature must be considered in addition to traditional mathematical models. Likewise, his idea of intrinsic randomness generation—that natural systems can generate their own randomness, rather than using chaos theory or stochastic perturbations—implies that computational models do not need to include explicit randomness.
Screw (simple machine) Distance moved Screw_(simple_machine) > Distance moved The linear distance d {\displaystyle d\,} a screw shaft moves when it is rotated through an angle of α {\displaystyle \alpha \,} degrees is: d = l α 360 ∘ {\displaystyle d=l{\frac {\alpha }{360^{\circ }}}\,} where l {\displaystyle l\,} is the lead of the screw. The distance ratio of a simple machine is defined as the ratio of the distance the applied force moves to the distance the load moves. For a screw it is the ratio of the circular distance din a point on the edge of the shaft moves to the linear distance dout the shaft moves. If r is the radius of the shaft, in one turn a point on the screw's rim moves a distance of 2πr, while its shaft moves linearly by the lead distance l. So the distance ratio is distance ratio ≡ d i n d o u t = 2 π r l {\displaystyle {\mbox{distance ratio}}\equiv {\frac {d_{in}}{d_{out}}}={\frac {2\pi r}{l}}\,}
H3R17me2 Epigenetic implications H3T45P > Epigenetic implications Different developmental stages were profiled in Drosophila as well, an emphasis was placed on histone modification relevance. A look in to the data obtained led to the definition of chromatin states based on histone modifications. Certain modifications were mapped and enrichment was seen to localize in certain genomic regions.
Graph homology The 1st homology group Graph_homology > The 1st homology group The general formula for the 1st homology group of a topological space X is: The example below explains these symbols and concepts in full detail on a graph.
Metal temper Alloy steels Metal_temper > Alloy steels Many elements are often alloyed with steel. The main purpose for alloying most elements with steel is to increase its hardenability and to decrease softening under temperature. Tool steels, for example, may have elements like chromium or vanadium added to increase both toughness and strength, which is necessary for things like wrenches and screwdrivers. On the other hand, drill bits and rotary files need to retain their hardness at high temperatures.
Yen's algorithm Pseudocode Yen's_algorithm > Algorithm > Pseudocode for i from 0 to size(A) − 2: // Spur node is retrieved from the previous k-shortest path, k − 1. spurNode = A.node(i); // The sequence of nodes from the source to the spur node of the previous k-shortest path. rootPath = A.nodes(0, i); for each path p in A: if rootPath == p.nodes(0, i): // Remove the links that are part of the previous shortest paths which share the same root path. remove p.edge(i,i + 1) from Graph; for each node rootPathNode in rootPath except spurNode: remove rootPathNode from Graph; // Calculate the spur path from the spur node to the sink.
Vacuum filter Cyclonic Vacuum_filter > Modern configurations > Cyclonic This is in marked contrast to filter bag systems, which lose suction when pores in the filter become clogged as dirt and dust are collected. In portable cyclonic models, the cleaned air from the center of the vortex is expelled from the machine after passing through a number of successively finer filters at the top of the container. The first filter is intended to trap particles which could damage the subsequent filters that remove fine dust particles.
Modprobe Summary Modprobe modprobe is a Linux program originally written by Rusty Russell and used to add a loadable kernel module to the Linux kernel or to remove a loadable kernel module from the kernel. It is commonly used indirectly: udev relies upon modprobe to load drivers for automatically detected hardware.Modprobe is distributed as part of the software package "kmod" (maintained by Lucas De Marchi and others). It was previously developed as: "module-init-tools", for Linux kernel version 2.6 and later (maintained by Jon Masters and others) "modutils" for use with Linux versions 2.2.x and 2.4.x. .
PH-tree Check quadrants for overlap with query box PH-tree > Operations > Window queries > Check quadrants for overlap with query box function is_overlap(h, h_min, h_max) is return (h \| h_min) & h_max == h // evaluates to 'true' if quadrant and query overlap. function query(node, min, max, result_list) is h_min ← calculate h_min h_max ← calculate h_max for each entry ← node.get_entries_range(h_min, h_max) do h ← entry.get_h(); if (h \| h_min) & h_max == h then // evaluates to 'true' if quadrant and query overlap. end if repeat return The resulting time complexity is O ( d + n n o d e _ e n t r i e s ) {\displaystyle O(d+n_{node\_entries})} compared to the O ( d ∗ n n o d e _ e n t r i e s ) {\displaystyle O(d*n_{node\_entries})} of the full iteration.
Woese's dogma Summary Woese's_dogma Woese's dogma is a principle of evolutionary biology first put forth by biophysicist Carl Woese in 1977. It states that the evolution of ribosomal RNA was a necessary precursor to the evolution of modern life forms. This led to the advancement of the phylogenetic tree of life consisting of three domains rather than the previously accepted two. While the existence of Eukarya and Prokarya were already accepted, Woese was responsible for the distinction between Bacteria and Archaea. Despite initial criticism and controversy surrounding his claims, Woese's three domain system, based on his work regarding the role of rRNA in the evolution of modern life, has become widely accepted.
Generative pre-trained transformer Foundational models Generative_pre-trained_transformer > Foundational models GPT-4 is a multi-modal LLM that is capable of processing text and image input (though its output is limited to text). Regarding multimodal output, some generative transformer-based models are used for text-to-image technologies such as diffusion and parallel decoding. Such kinds of models can serve as visual foundation models (VFMs) for developing downstream systems that can work with images.
Uncertainty Principle (Numbers) Writing Uncertainty_Principle_(Numbers) > Production > Writing "Uncertainty Principle" is based on a series of bank robberies, solved with the assistance of an Arkansas mathematician, that occurred in Maryland in 2004. Since bank robbers follow predictable patterns, the FBI called in the mathematician to specifically predict which banks were likely targets. The bank robber was arrested while selecting his next target.Early in the series, series creators Cheryl Heuton and Nicolas Falacci decided that one of the elements in the series would be the emotional effects of cases on the characters.
Ergosophy Summary Ergosophy Ergosophy is a term coined by the scientist Frederick Soddy, in the early 1920s, and refers to aspects of energy in relation to human existence and energy measurement as in (Ergs). Soddy's aim was to apply science theories and ideas and move the human understanding of work beyond the restrictions of management theory into a new theory of energy economics. Frederick Soddy first used the term in his book on work and economics: The Role of Money.
Johannes Kepler Works Johannes_Kepler > Works Vol. 11,1: Ephemerides novae motuum coelestium. Commentary V. Bialas.
Umple Features and capabilities Umple > Features and capabilities When this is done, Umple can be seen as a pre-processor: The Umple compiler expands the UML constructs into code of the target language. Code in a target language can be passed to the Umple compiler directly; if no Umple-specific notation is found, then the target-language code is emitted unchanged by the Umple compiler. Umple, combined with one of its target languages for imperative code, can be seen and used as a complete programming language.
Situated knowledge Science Human_knowledge > In various disciplines > Science The hypothesis is then tested using a controlled experiment to compare whether predictions based on the hypothesis match the actual results. As a last step, the results are interpreted and a conclusion is reached whether and to what degree the findings confirm or disconfirm the hypothesis.The progress of scientific knowledge is traditionally seen as a gradual and continuous process in which the existing body of knowledge is increased in each step. However, this view has been challenged by some philosophers of science, such as Thomas Kuhn.
Benchmark program Purpose Benchmark_(computing) > Purpose See BogoMips and the megahertz myth. Benchmarks are designed to mimic a particular type of workload on a component or system. Synthetic benchmarks do this by specially created programs that impose the workload on the component.
Polystyrene Sheet or molded polystyrene Expanded_Polystyrene > Forms produced > Sheet or molded polystyrene Polystyrene (PS) is used for producing disposable plastic cutlery and dinnerware, CD "jewel" cases, smoke detector housings, license plate frames, plastic model assembly kits, and many other objects where a rigid, economical plastic is desired. Production methods include thermoforming (vacuum forming) and injection molding. Polystyrene Petri dishes and other laboratory containers such as test tubes and microplates play an important role in biomedical research and science.
Computing science Computer security and cryptography Computer_sciences > Fields > Computer systems > Computer security and cryptography Computer security is a branch of computer technology with the objective of protecting information from unauthorized access, disruption, or modification while maintaining the accessibility and usability of the system for its intended users. Historical cryptography is the art of writing and deciphering secret messages. Modern cryptography is the scientific study of problems relating to distributed computations that can be attacked. Technologies studied in modern cryptography include symmetric and asymmetric encryption, digital signatures, cryptographic hash functions, key-agreement protocols, blockchain, zero-knowledge proofs, and garbled circuits.
Neural networks Criticism Neural_networks > Criticism Arguments against Dewdney's position are that neural nets have been successfully used to solve many complex and diverse tasks, such as autonomously flying aircraft.Technology writer Roger Bridgman commented on Dewdney's statements about neural nets: Neural networks, for instance, are in the dock not only because they have been hyped to high heaven, (what hasn't?) but also because you could create a successful net without understanding how it worked: the bunch of numbers that captures its behaviour would in all probability be "an opaque, unreadable table...valueless as a scientific resource". In spite of his emphatic declaration that science is not technology, Dewdney seems here to pillory neural nets as bad science when most of those devising them are just trying to be good engineers.
T cell Cytotoxic CD8+ T cells T_lymphocyte > Types of T cell > Conventional adaptive T cells > Cytotoxic CD8+ T cells Cytotoxic T cells (TC cells, CTLs, T-killer cells, killer T cells) destroy virus-infected cells and tumor cells, and are also implicated in transplant rejection. These cells are defined by the expression of the CD8 protein on their cell surface. Cytotoxic T cells recognize their targets by binding to short peptides (8-11 amino acids in length) associated with MHC class I molecules, present on the surface of all nucleated cells. Cytotoxic T cells also produce the key cytokines IL-2 and IFNγ. These cytokines influence the effector functions of other cells, in particular macrophages and NK cells.
Shared-memory multiprocessor Support on Unix-like systems Shared_memory_system > In software > Support on Unix-like systems It stays in the system until explicitly removed by a process. This has a drawback in that if the process crashes and fails to clean up shared memory it will stay until system shutdown; that limitation is not present in an Android-specific implementation dubbed ashmem.POSIX also provides the mmap API for mapping files into memory; a mapping can be shared, allowing the file's contents to be used as shared memory. Linux distributions based on the 2.6 kernel and later offer /dev/shm as shared memory in the form of a RAM disk, more specifically as a world-writable directory (a directory in which every user of the system can create files) that is stored in memory. Both the RedHat and Debian based distributions include it by default. Support for this type of RAM disk is completely optional within the kernel configuration file.
Solid-state nuclear magnetic resonance Chemical shielding Solid-state_nuclear_magnetic_resonance > Nuclear spin interactions > Chemical shielding Chemical shielding is a local property of each nuclear site in a molecule or compound, and is proportional to the applied external magnetic field. The external magnetic field induces currents of the electrons in molecular orbitals. These induced currents create local magnetic fields that lead to characteristic changes in resonance frequency. These changes can be predicted from molecular structure using empirical rules or quantum-chemical calculations. In general, the chemical shielding is anisotropic because of the anisotropic distribution of molecular orbitals around the nuclear sites. Under sufficiently fast magic angle spinning, or under the effect of molecular tumbling in solution-state NMR, the anisotropic dependence of the chemical shielding is time-averaged to zero, leaving only the isotropic chemical shift.

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