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9 Algorithms That Changed the Future Summary 9_Algorithms_That_Changed_the_Future 9 Algorithms that Changed the Future is a 2012 book by John MacCormick on algorithms. The book seeks to explain commonly encountered computer algorithms to a layman audience.
Parasitic RNA Segregation distorters Selfish_genes > Examples > Segregation distorters Some selfish genetic elements manipulate the genetic transmission process to their own advantage, and so end up being overrepresented in the gametes. Such distortion can occur in various ways, and the umbrella term that encompasses all of them is segregation distortion. Some elements can preferentially be transmitted in egg cells as opposed to polar bodies during meiosis, where only the former will be fertilized and transmitted to the next generation. Any gene that can manipulate the odds of ending up in the egg rather than the polar body will have a transmission advantage, and will increase in frequency in a population.Segregation distortion can happen in several ways.
System development methodology Rapid application development Software_Process > Methodologies > Rapid application development Attempts to reduce inherent project risk by breaking a project into smaller segments and providing more ease of change during the development process. Aims to produce high-quality systems quickly, primarily via iterative Prototyping (at any stage of development), active user involvement, and computerized development tools. These tools may include Graphical User Interface (GUI) builders, Computer Aided Software Engineering (CASE) tools, Database Management Systems (DBMS), fourth-generation programming languages, code generators, and object-oriented techniques.
Quadratic reciprocity law The supplementary laws using Legendre symbols Quadratic_Reciprocity > History and alternative statements > Legendre and his symbol > The supplementary laws using Legendre symbols If u 2 ≡ − b c mod a v 2 ≡ − c a mod b w 2 ≡ − a b mod c {\displaystyle {\begin{aligned}u^{2}&\equiv -bc{\bmod {a}}\\v^{2}&\equiv -ca{\bmod {b}}\\w^{2}&\equiv -ab{\bmod {c}}\end{aligned}}} are solvable then the following equation has a nontrivial solution in integers: a x 2 + b y 2 + c z 2 = 0. {\displaystyle ax^{2}+by^{2}+cz^{2}=0.} Example.
SecPAL Common access control requirements SecPAL > Common access control requirements Here is a partial-list of some of the challenges that SecPAL addresses: How does an organization establish a fine-grained trust relationship with another organization across organizational boundaries? How does a user delegate a subset of a user’s rights (constrained delegation) to another user residing either in the same organization or in a different organization? How can access control policy be authored and reviewed in a manner that is human readable - allowing auditors and non-technical people to understand such policies? How does an organization support compliance regulations requiring that a system be able to demonstrate exactly why it was that a user was granted access to a resource? How can policies be authored, composed and evaluated in a manner that is efficient, deterministic and tractable?
Space-charge limited current Physical explanation Space_charge > Cause > Physical explanation Space charge can result from a range of phenomena, but the most important are: Combination of the current density and spatially inhomogeneous resistance Ionization of species within the dielectric to form heterocharge Charge injection from electrodes and from a stress enhancement Polarization in structures such as water trees. "Water tree" is a name given to a tree-like figure appearing in a water-impregnated polymer insulating cable.It has been suggested that in alternating current (AC) most carriers injected at electrodes during a half of cycle are ejected during the next half cycle, so the net balance of charge on a cycle is practically zero. However, a small fraction of the carriers can be trapped at levels deep enough to retain them when the field is inverted. The amount of charge in AC should increase slower than in direct current (DC) and become observable after longer periods of time.
Bacteriophage φX174 Infection Cycle Bacteriophage_φX174 > Infection Cycle Similarly, gene transcripts for F, J, and G are more abundant than for H as the stoichiometry for these structural proteins is 5:5:5:1. The primosomes are protein complexes which attach/bind the enzyme helicase on the template. Primosomes gives RNA primers for DNA synthesis to strands.
Bode plotter Rules for handmade Bode plot Bode_Plot > Rules for handmade Bode plot The premise of a Bode plot is that one can consider the log of a function in the form: f ( x ) = A ∏ ( x − c n ) a n {\displaystyle f(x)=A\prod (x-c_{n})^{a_{n}}} as a sum of the logs of its zeros and poles: log ⁡ ( f ( x ) ) = log ⁡ ( A ) + ∑ a n log ⁡ ( x − c n ) . {\displaystyle \log(f(x))=\log(A)+\sum a_{n}\log(x-c_{n})\;.} This idea is used explicitly in the method for drawing phase diagrams. The method for drawing amplitude plots implicitly uses this idea, but since the log of the amplitude of each pole or zero always starts at zero and only has one asymptote change (the straight lines), the method can be simplified.
Vernier caliper Zero error Digital_caliper > Zero error The method to use a vernier scale or caliper with zero error is to use the formula "actual reading = main scale + vernier scale − (zero error)". Zero error may arise due to knocks that affect the calibration at 0.00 mm when the jaws are perfectly closed or just touching each other. Positive zero error refers to the fact that when the jaws of the vernier caliper are just closed, the reading is a positive reading away from the actual reading of 0.00 mm. If the reading is 0.10 mm, the zero error is referred to as +0.10 mm. Negative zero error refers to the fact that when the jaws of the vernier caliper are just closed, the reading is a negative reading away from the actual reading of 0.00 mm. If the reading is −0.08 mm, the zero error is referred to as −0.08 mm.
Life Length Telomeres and their importance to the company Life_Length > Telomeres and their importance to the company Over the years, every time a cell divides, our telomeres successively shorten up to a point where the cells cannot divide any more. Subsequently, they either undergo a process called apoptosis (cells progressively die) or go into senescence (they lose their function).
Data monetization Frameworks Data_monetization > Frameworks They pull in data from a wide array of sources (including their own homegrown data), integrate it into a unified stream, make it consumable via a dashboard or through an API, and offer a robust analytics suite for a staggering number of use cases. Needless to say, their scale and profitability is the envy of the industry. Data creation platforms.
Obeticholic acid Nonalcoholic steatohepatitis (NASH) Obeticholic_acid > Clinical studies > Nonalcoholic steatohepatitis (NASH) Non-alcoholic steatohepatitis is a common cause of abnormal liver function with histological features of fatty liver, inflammation and fibrosis. It may progress to cirrhosis and is becoming an increasing indication for liver transplantation. It is increasing in prevalence. OCA is proposed to treat NASH.
Leptokurtic distribution Summary Excess_kurtosis In probability theory and statistics, kurtosis (from Greek: κυρτός, kyrtos or kurtos, meaning "curved, arching") is a measure of the "tailedness" of the probability distribution of a real-valued random variable. Like skewness, kurtosis describes a particular aspect of a probability distribution. There are different ways to quantify kurtosis for a theoretical distribution, and there are corresponding ways of estimating it using a sample from a population.
Supercomputer architecture Early systems with a few processors Supercomputer_architecture > Early systems with a few processors Two issues that need to be addressed as the number of processors increases are the distribution of memory and processing. In the distributed memory approach, each processor is physically packaged close with some local memory. The memory associated with other processors is then "further away" based on bandwidth and latency parameters in non-uniform memory access.
The fundamental theorem of algebra Recent literature The_fundamental_theorem_of_algebra > References > Recent literature On the history of the fundamental theorem of algebra: theory of equations and integral calculus.) Netto, Eugen; Le Vavasseur, Raymond (1916), "Les fonctions rationnelles §80–88: Le théorème fondamental", in Meyer, François; Molk, Jules (eds. ), Encyclopédie des Sciences Mathématiques Pures et Appliquées, tome I, vol.
Vector subtraction Mathematical treatments Antiparallel_vector > References > Mathematical treatments Ivanov, A.B. (2001) , "Vector", Encyclopedia of Mathematics, EMS Press. Kane, Thomas R.; Levinson, David A.
Oracle NoSQL Database Summary Oracle_NoSQL_Database NoSQL Database supports tabular model. Each row is identified by a unique key, and has a value, of arbitrary length, which is interpreted by the application. The application can manipulate (insert, delete, update, read) a single row in a transaction. The application can also perform an iterative, non-transactional scan of all the rows in the database.
Bacterial transcription Elongation Bacterial_transcription > Elongation Due to the quick nature of this process, DNA is continually unwound ahead of RNA polymerase and then rewound once RNA polymerase moves along further. The polymerase has a proofreading mechanism that limits mistakes to about 1 in 10,000 nucleotides transcribed. RNA polymerase has lower fidelity (accuracy) and speed than DNA polymerase. DNA polymerase has a very different proofreading mechanism that includes exonuclease activity, which contributes to the higher fidelity. The consequence of an error during RNA synthesis is usually harmless, where as an error in DNA synthesis could be detrimental.The promoter sequence determines the frequency of transcription of its corresponding gene.
Photographic lens design Lens elements Photographic_lens_design > Design > Lens elements With this design one can achieve a good degree of convergence of different wavelengths in the visible spectrum. Most lens designs do not attempt to bring infrared wavelengths to the same common focus and it is therefore necessary to manually alter the focus when photographing in infrared light. Other kinds of aberrations such as coma or astigmatism can also be minimized by careful choice of curvature of the lens faces for all the component elements.
Crista Electron transport chain of the cristae Crista > Electron transport chain of the cristae As a result, they form two molecules of water (H2O). By accepting the electrons, oxygen allows the electron transport chain to continue functioning. The chain is organized in the cristae lumen membrane, i.e. the membrane inside the junction.The electrons from each NADH molecule can form a total of 3 ATP's from ADPs and phosphate groups through the electron transport chain, while each FADH2 molecule can produce a total of 2 ATPs. As a result, 10 NADH molecules (from glycolysis and the Krebs cycle), along with 2 FADH2 molecules, can form a total of 34 ATPs during aerobic respiration (from a single electron transport chain). This means that combined with the Krebs Cycle and glycolysis, the efficiency for the electron transport chain is about 65%, as compared to only 3.5% efficiency for glycolysis alone.
RNA silencing Laboratory RNA_silencing > Practical applications > Laboratory Overall, synthetic and natural small RNAs have proven to be an important tool for studying gene function in cells as well as animals.Bioinformatics approaches to identify small RNAs and their targets have returned several hundred, if not thousands of, small RNA candidates predicted to affect gene expression in plants, C. elegans, D. melanogaster, zebrafish, mouse, rat, and human. These methods are largely directed to identifying small RNA candidates for knock-out experiments but may have broader applications. One bioinformatics approach evaluated sequence conservation criteria by filtering seed complementary target-binding sites. The cited study predicted that approximately one third of mammalian genes were to be regulated by, in this case, miRNAs.
Customer segmentation History Market_segmentation > History This is the era of market differentiation based on demographic, socio-economic, and lifestyle factors. Hyper-segmentation (post-1980s): a shift towards the definition of ever more narrow market segments.
ADSL modem Data rates and access DSL_modems > Technology > Data rates and access Most consumer DSL lines use one of several varieties of Asymmetric DSL (ADSL). The "asymmetric" means that more of the bandwidth of the line is dedicated to downstream (download) data than upstream (upload) data, so, download rates are faster than upload rates, because most users download much larger quantities of data than they upload. Because the telephone lines were never designed to carry such high frequency signals, DSL is distance-sensitive. The farther away from the switching center the modem is, the longer the telephone wires, the weaker the signal, and the lower the data rate that the modem can achieve.
Quantum Supremacy Reception Quantum_Supremacy > Reception Scott Aaronson, professor of computer science at the University of Texas at Austin, severely panned Kaku's book on his blog, Shtetl-Optimized. Aaronson wrote, "beating out a crowded field, this is the worst book about quantum computing, for some definition of the word 'about,' that I’ve ever encountered," describing the book as a "kindergarten of lies." After pointing out several substantial factual errors, Aaronson concluded that "the bulk of the book is actually about stuff with no direct relation to quantum computing at all—the origin of life, climate change, energy generation, cancer, curing aging, etc.—except with ungrounded speculations tacked onto the end of each chapter about how quantum computers will someday revolutionize all of this. "Reviews from non-specialists were mixed to positive.
Nonalcoholic fatty liver disease Dysbiosis Non-alcoholic_fatty_liver_disease > Pathophysiology > Dysbiosis The increased transport of these harmful substances to the liver promotes liver inflammation, enhances nutrient and calorie absorption, and alters choline metabolism. Higher levels of intestinal bacteria that produce butyrate may be protective.Excessive macronutrient intake contributes to gut inflammation and perturbation of homeostasis, and micronutrients may also be involved.
The Entropy Effect Plot summary The_Entropy_Effect > Plot summary Spock returns to the restored timeline to find that all is well, but that he has the memories of both realities. Spock decides not to reveal any of this and informs Kirk that the singularity is in the process of self-destructing. In a subplot, Hikaru Sulu requests a transfer to the fighter ship Aerfen. The novel ends with Kirk granting Sulu a field promotion in order to keep him on the Enterprise.
Creationism Biblical basis Creationism > Biblical basis The basis for many creationists' beliefs is a literal or quasi-literal interpretation of the Book of Genesis. The Genesis creation narratives (Genesis 1–2) describe how God brings the Universe into being in a series of creative acts over six days and places the first man and woman (Adam and Eve) in the Garden of Eden. This story is the basis of creationist cosmology and biology.
Euler tour tree Euler tour trees Euler_tour_tree > Euler tour trees Link/cut trees have similar performance guarantees. While LC trees are good for maintaining aggregates on paths of a tree (making it a good choice data structure in network flow algorithms), ET trees are better at keeping aggregate information on subtrees. == References ==
Symplectic groupoid History Poisson_manifold > Introduction > History Although the modern definition of Poisson manifold appeared only in the 70's–80's, its origin dates back to the nineteenth century. Alan Weinstein synthetised the early history of Poisson geometry as follows:"Poisson invented his brackets as a tool for classical dynamics. Jacobi realized the importance of these brackets and elucidated their algebraic properties, and Lie began the study of their geometry." Indeed, Siméon Denis Poisson introduced in 1809 what we now call Poisson bracket in order to obtain new integrals of motion, i.e. quantities which are preserved throughout the motion.
Gilbert Froment Tenure at the Ghent University Gilbert_Froment > Education > Tenure at the Ghent University One of the notable areas of his research has been the study of transport mechanisms within catalyst particles. In contrast to earlier approaches that treated catalyst particles as single pores or pseudo-continua, Froment recognized the importance of retaining network topology in modeling. He particularly emphasized the preservation of network connectivity, especially in cases where pores could be obstructed due to factors like metal deposition or coke formation.
Glossary of Lie groups and Lie algebras R Glossary_of_Lie_groups_and_Lie_algebras > R radical 1. The radical of a Lie group. 2.
Autoimmune regulator Function Autoimmune_regulator > Function In the thymus, the AIRE causes transcription of a wide selection of organ-specific genes that create proteins that are usually only expressed in peripheral tissues, creating an "immunological self-shadow" in the thymus. It is important that self-reactive T cells that bind strongly to self-antigen are eliminated in the thymus (via the process of negative selection), otherwise they may later encounter and bind to their corresponding self-antigens and initiate an autoimmune reaction. So the expression of non-local proteins by AIRE in the thymus reduces the threat of autoimmunity by promoting the elimination of auto-reactive T cells that bind antigens not normally found in the thymus.
15 equal temperament Summary 15_equal_temperament In music, 15 equal temperament, called 15-TET, 15-EDO, or 15-ET, is a tempered scale derived by dividing the octave into 15 equal steps (equal frequency ratios). Each step represents a frequency ratio of 15√2 (=2(1/15)), or 80 cents (). Because 15 factors into 3 times 5, it can be seen as being made up of three scales of 5 equal divisions of the octave, each of which resembles the Slendro scale in Indonesian gamelan. 15 equal temperament is not a meantone system.
Cognitive rigor Summary Cognitive_rigor Cognitive rigor is a combined model developed by superimposing two existing models for describing rigor that are widely accepted in the education system in the United States. The concept "is marked and measured by the depth and extent students are challenged and engaged to demonstrate and communicate their knowledge and thinking" and also "marks and measures the depth and complexity of student learning experiences. "Cognitive Rigor is the superposition of Bloom's Taxonomy and Webb's Depth-of-Knowledge levels and is used to categorize the level of abstraction of questions and activities in education. The Cognitive Rigor Matrix assists applying Cognitive Rigor in the classroom.
Rooted binary tree Summary Rooted_binary_tree It is also possible to interpret a binary tree as an undirected, rather than a directed graph, in which case a binary tree is an ordered, rooted tree. Some authors use rooted binary tree instead of binary tree to emphasize the fact that the tree is rooted, but as defined above, a binary tree is always rooted. A binary tree is a special case of an ordered K-ary tree, where K is 2.
RNase R Summary RNase_R RNase R, or Ribonuclease R, is a 3'-->5' exoribonuclease, which belongs to the RNase II superfamily, a group of enzymes that hydrolyze RNA in the 3' - 5' direction. RNase R has been shown to be involved in selective mRNA degradation, particularly of non stop mRNAs in bacteria. RNase R has homologues in many other organisms. When a part of another larger protein has a domain that is very similar to RNase R, this is called an RNase R domain.
Signal-to-noise ratio Frequency modulation Signal_to_noise_ratio > Modulation system measurements > Frequency modulation Channel signal-to-noise ratio is given by ( S N R ) C , F M = A c 2 2 W N 0 {\displaystyle \mathrm {(SNR)_{C,FM}} ={\frac {A_{c}^{2}}{2WN_{0}}}} Output signal-to-noise ratio is given by ( S N R ) O , F M = A c 2 k f 2 P 2 N 0 W 3 {\displaystyle \mathrm {(SNR)_{O,FM}} ={\frac {A_{c}^{2}k_{f}^{2}P}{2N_{0}W^{3}}}}
Classical billiard balls Beyond Newton's laws Classical_Newtonian_model > Description of the theory > Beyond Newton's laws Classical mechanics also describes the more complex motions of extended non-pointlike objects. Euler's laws provide extensions to Newton's laws in this area. The concepts of angular momentum rely on the same calculus used to describe one-dimensional motion.
Sure-thing principle Summary Sure-thing_principle In decision theory, the sure-thing principle states that a decision maker who decided they would take a certain action in the case that event E has occurred, as well as in the case that the negation of E has occurred, should also take that same action if they know nothing about E. The principle was coined by L.J. Savage: A businessman contemplates buying a certain piece of property. He considers the outcome of the next presidential election relevant. So, to clarify the matter to himself, he asks whether he would buy if he knew that the Democratic candidate were going to win, and decides that he would.
Evolutionary reversal Summary Reverse_evolution Devolution, de-evolution, or backward evolution (not to be confused with dysgenics) is the notion that species can revert to supposedly more primitive forms over time. The concept relates to the idea that evolution has a purpose (teleology) and is progressive (orthogenesis), for example that feet might be better than hooves or lungs than gills. However, evolutionary biology makes no such assumptions, and natural selection shapes adaptations with no foreknowledge of any kind. It is possible for small changes (such as in the frequency of a single gene) to be reversed by chance or selection, but this is no different from the normal course of evolution and as such de-evolution is not compatible with a proper understanding of evolution due to natural selection.
Electron affinity (data page) Specific molecules Electron_affinity_(data_page) > Bibliography > Specific molecules ; Lineberger, W.C. ; Marks, J.; Brauman, J.I. (1984), "Spectroscopy and dynamics of the dipole-bound state of acetaldehyde enolate", J. Chem.
Middle lamella Summary Middle_lamella The middle lamella is a layer that cements together the primary cell walls of two adjoining plant cells. It is the first formed layer to be deposited at the time of cytokinesis. The cell plate that is formed during cell division itself develops into middle lamella or lamellum.
Longest processing time Input consideration Longest_processing_time > Performance guarantees: identical machines > Worst-case maximum sum > Input consideration An even more detailed analysis takes into account the number of inputs in the max-sum part. In each part of the greedy partition, the j-th highest number is at most O P T / j {\displaystyle OPT/j} . Suppose that, in the greedy part P with the max-sum, there are L inputs. Then, the approximation ratio of the greedy algorithm is L + 1 L − 1 L m = 1 + 1 L − 1 L m {\displaystyle {\frac {L+1}{L}}-{\frac {1}{Lm}}=1+{\frac {1}{L}}-{\frac {1}{Lm}}} .
Reactivity (nuclear) Fission chain reaction Reactivity_(nuclear) > Fission chain reaction Thus, the cycle repeats to give a reaction that is self-sustaining. Nuclear power plants operate by precisely controlling the rate at which nuclear reactions occur. Nuclear weapons, on the other hand, are specifically engineered to produce a reaction that is so fast and intense it cannot be controlled after it has started. When properly designed, this uncontrolled reaction will lead to an explosive energy release.
Water motors Constant pressure and load-sensing systems Hydraulic_drive_system > Constant pressure and load-sensing systems Hydrostatic transmissions for earth moving machines, such as for track loaders, are often equipped with a separate 'inch pedal' that is used to temporarily increase the diesel engine rpm while reducing the vehicle speed in order to increase the available hydraulic power output for the working hydraulics at low speeds and increase the tractive effort. The function is similar to stalling a converter gearbox at high engine rpm. The inch function affects the preset characteristics for the 'hydrostatic' gear ratio versus diesel engine rpm.
Reaction mechanism Molecularity Reaction_mechanism > Molecularity Molecularity in chemistry is the number of colliding molecular entities that are involved in a single reaction step. A reaction step involving one molecular entity is called unimolecular. A reaction step involving two molecular entities is called bimolecular. A reaction step involving three molecular entities is called trimolecular or termolecular.In general, reaction steps involving more than three molecular entities do not occur, because is statistically improbable in terms of Maxwell distribution to find such a transition state.
Small nucleolar RNA SNORD25 Summary Small_nucleolar_RNA_SNORD25 In molecular biology, snoRNA U25 (also known as SNORD25) is a non-coding RNA (ncRNA) molecule which functions in the biogenesis (modification) of other small nuclear RNAs (snRNAs). This type of modifying RNA is 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. U25 is a member of the C/D box class of snoRNAs which contain the conserved sequence motifs known as the C box (UGAUGA) and the D box (CUGA).
Axiom of amalgamation Relation to Replacement Axiom_of_union > Relation to Replacement The axiom of replacement allows one to form many unions, such as the union of two sets. However, in its full generality, the axiom of union is independent from the rest of the ZFC-axioms: Replacement does not prove the existence of the union of a set of sets if the result contains an unbounded number of cardinalities. Together with the axiom schema of replacement, the axiom of union implies that one can form the union of a family of sets indexed by a set.
Glossary of genetics (0–L) B Glossary_of_gene_expression_terms > B Some methods involve the transfer of molecules by capillary action (e.g. Southern and northern blotting), while others rely on the transport of charged molecules by electrophoresis (e.g. western blotting). The transferred molecules are then visualized by colorant staining, autoradiography, or the selective labelling of molecules containing specific sequences or epitopes with hybridization probes or antibodies bound to a chemiluminescent reporter. blunt end bromodeoxyuridine (BUDR, BrdU) Also 5-bromodeoxyuridine.
Slope stability analysis Discontinuum modelling Slope_stability_analysis > Numerical methods of analysis > Discontinuum modelling Spherical particles interact through frictional sliding contacts. Simulation of joint bounded blocks may be realized through specified bond strengths.
Internet Of Things Network architecture Internet_Of_Things > Trends and characteristics > Architecture > Network architecture The Internet of things requires huge scalability in the network space to handle the surge of devices. IETF 6LoWPAN can be used to connect devices to IP networks. With billions of devices being added to the Internet space, IPv6 will play a major role in handling the network layer scalability.
Vegetable oils as alternative energy Generation and storage Palm_oil_diesel > Generation and storage Technologies of hydrogen economy, batteries, compressed air energy storage, and flywheel energy storage address the energy storage problem but not the source of primary energy. Other technologies like fission power, fusion power, and solar power address the problem of a source of primary energy but not energy storage. Vegetable oil addresses both the source of primary energy and of energy storage. The cost and weight to store a given amount of energy as vegetable oil is low compared to many of the potential replacements for fossil fuels.
Dilution of precision (GPS) Introduction Dilution_of_precision_(GPS) > Introduction The opposite of this ideal is the situation where the solution is very sensitive to measurement errors. The interpretation of this formula is shown in the figure to the right, showing two possible scenarios with acceptable and poor GDOP. More recently, the term has come into much wider usage with the development and adoption of GPS.
Digital infinity The computational theory of mind Digital_infinity > The computational theory of mind This way, digital computation and communication operates independently of the physical properties of the computing machine. As scientists and philosophers during the 1950s digested the implications, they exploited the insight to explain why 'mind' apparently operates on so different a level from 'matter'. Descartes's celebrated distinction between immortal 'soul' and mortal 'body' was conceptualised, following Turing, as no more than the distinction between (digitally encoded) information on the one hand, and, on the other, the particular physical medium—light, sound, electricity or whatever—chosen to transmit the corresponding signals.
Permissioned blockchain Summary Blockchain_2.0 A blockchain is a distributed ledger with growing lists of records (blocks) that are securely linked together via cryptographic hashes. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data (generally represented as a Merkle tree, where data nodes are represented by leaves). Since each block contains information about the previous block, they effectively form a chain (compare linked list data structure), with each additional block linking to the ones before it. Consequently, blockchain transactions are irreversible in that, once they are recorded, the data in any given block cannot be altered retroactively without altering all subsequent blocks.
Filoviridae Life cycle Filoviridae > Life cycle The filovirus life cycle begins with virion attachment to specific cell-surface receptors, followed by fusion of the virion envelope with cellular membranes and the concomitant release of the virus nucleocapsid into the cytosol. The viral RNA-dependent RNA polymerase (RdRp, or RNA replicase) partially uncoats the nucleocapsid and transcribes the genes into positive-stranded mRNAs, which are then translated into structural and nonstructural proteins. Filovirus RdRps bind to a single promoter located at the 3' end of the genome. Transcription either terminates after a gene or continues to the next gene downstream.
Theory of computability Frequency computation Turing_computability > Areas of research > Frequency computation This branch of computability theory analyzed the following question: For fixed m and n with 0 < m < n, for which functions A is it possible to compute for any different n inputs x1, x2, ..., xn a tuple of n numbers y1, y2, ..., yn such that at least m of the equations A(xk) = yk are true. Such sets are known as (m, n)-recursive sets. The first major result in this branch of computability theory is Trakhtenbrot's result that a set is computable if it is (m, n)-recursive for some m, n with 2m > n. On the other hand, Jockusch's semirecursive sets (which were already known informally before Jockusch introduced them 1968) are examples of a set which is (m, n)-recursive if and only if 2m < n + 1.
Mark Z. Jacobson Soot and aerosol Mark_Z._Jacobson > Research > Soot and aerosol On the other hand, greenhouse gases warm the atmosphere by trapping thermal-infrared heat radiation that is emitted by the surface of the Earth.Jacobson found that, as soot particles in the air age, they grow larger due to condensation by gases and collision/coalescence with other particles. He further found that when a soot particle obtained such a coating, more sunlight enters the particles, bounces around, and eventually gets absorbed by the black carbon. On a global scale, this may result in twice the heating by black carbon as uncoated particles.
Bioenergetic systems Ketolysis Bioenergetic_systems > Aerobic metabolism > Ketolysis During starvation or while consuming a low-carb/ketogenic diet, the liver produces ketones. Ketones are needed as fatty acids cannot pass the blood-brain barrier, blood glucose levels are low and glycogen reserves depleted. Ketones also convert to acetyl-CoA faster than fatty acids.
Plasmacytoid dendritic cell HIV Plasmacytoid_dendritic_cell > Role in autoimmunity and diseases > HIV The mass production of type 1 interferon may result in both positive and negative outcomes in response to HIV. Although type 1 interferon is efficient at facilitating maturation in pDCs and in killing infected T cells, excessive clearance of infected T cells may have detrimental effects and further weaken the patient's compromised immune system. pDCs themselves can be infected by HIV but are also capable of sensing viral markers such as ssRNA and are impaired in their interferon-producing capacities.
Polymerase Chain Reaction Stages Applications_of_PCR > Principles > Stages As with other chemical reactions, the reaction rate and efficiency of PCR are affected by limiting factors. Thus, the entire PCR process can further be divided into three stages based on reaction progress: Exponential amplification: At every cycle, the amount of product is doubled (assuming 100% reaction efficiency). After 30 cycles, a single copy of DNA can be increased up to 1,000,000,000 (one billion) copies. In a sense, then, the replication of a discrete strand of DNA is being manipulated in a tube under controlled conditions.
Molecular Neuroscience Alzheimer's disease Molecular_Neuroscience > Molecular mechanisms of neurodegenerative diseases > Alzheimer's disease Alzheimer's disease is the most common neurodegenerative disease and is the most common form of dementia in the elderly. The disorder is characterized by progressive loss of memory and various cognitive functions. It is hypothesized that the deposition of amyloid-β peptide (40-42 amino acid residues) in the brain is integral in the incidence of Alzheimer's disease. Accumulation is purported to block hippocampal long-term potentiation. It is also possible that a receptor for amyloid-β oligomers could be a prion protein.
Multimeter Analog Multimeter > Designs > Analog In the usual circuits found in analog multimeters, the meter deflection is inversely proportional to the resistance, so full-scale will be 0 Ω, and higher resistance will correspond to smaller deflections. The ohms scale is compressed, so resolution is better at lower resistance values. Amplified instruments simplify the design of the series and shunt resistor networks.
Ralph Merkle puzzle cryptographic system Complexity and security analysis Ralph_Merkle_puzzle_cryptographic_system > Complexity and security analysis The parameters of the puzzle game can be chosen to make it considerably harder to for an eavesdropper to break the code than for the parties to communicate, but Merkle puzzles do not provide the enormous qualitative differences in difficulty that are required for (and define) security in modern cryptography. Suppose that the number of puzzles sent by Bob is m, and it takes both Bob and Alice n steps of computation to solve one puzzle. Then both can deduce a common session key within a time complexity of O(m+n). Eve, in contrast, is required to solve all puzzles, which takes her O(mn) of time.
Optimizing compilers Practical considerations Compiler_optimization > Practical considerations There can be a wide range of optimizations that a compiler can perform, ranging from the simple and straightforward that take little compilation time to the elaborate and complex that involve considerable amounts of compilation time. Accordingly, compilers often provide options to their control command or procedure to allow the compiler user to choose how much optimization to request; for instance, the IBM FORTRAN H compiler allowed the user to specify no optimization, optimization at the registers level only, or full optimization. By the 2000s, it was common for compilers, such as Clang, to have a number of compiler command options that could affect a variety of optimization choices, starting with the familiar -O2 switch.An approach to isolating optimization is the use of so-called post-pass optimizers (some commercial versions of which date back to mainframe software of the late 1970s). These tools take the executable output by an optimizing compiler and optimize it even further.
Wall-clock time In simulation Wall-clock_time > In simulation The term wall-clock time has also found widespread adoption in computer simulation, to distinguish between (1) the (often compressed or expanded) simulation time, and (2) the time as it passes for the user of the simulation tool. == References ==
Smiling curve Trend of industries development Smiling_curve > Theory origins > Trend of industries development In order to overcome the pressure of low added value, enterprise's only recourse is to move towards high-value added industry trends. Mastering the key technology and key components is high added value; general manufacturing or OEM is low added value; product integration service also produce high added value.
MicA RNA Function MicA_RNA > Function Based on its conservation, this is presumably the case in close relatives and may serve as a long elusive link between envelope stress and quorum sensing. The PhoPQ two-component system is repressed by MicA. The RNA presumably pairs with the ribosomal binding site of phoP mRNA, thereby inhibiting translation.
Java EE Connector Architecture Contracts J2EE_Connector_Architecture > Contracts This leads to a scalable application environment that can support a large number of clients. Transaction management Transaction management enables an application server to use a transaction manager to manage transactions across multiple resource managers.
Kernel (statistics) Bayesian statistics Kernel_estimation > Bayesian statistics In statistics, especially in Bayesian statistics, the kernel of a probability density function (pdf) or probability mass function (pmf) is the form of the pdf or pmf in which any factors that are not functions of any of the variables in the domain are omitted. Note that such factors may well be functions of the parameters of the pdf or pmf. These factors form part of the normalization factor of the probability distribution, and are unnecessary in many situations. For example, in pseudo-random number sampling, most sampling algorithms ignore the normalization factor.
Organomolybdenum chemistry Mo(0) and more reduced states Organotungsten_chemistry > Mo(0) and more reduced states Cycloheptatrienemolybdenum tricarbonyl, which is related to (arene)Mo(CO)3, reacts with trityl salts to give the cycloheptatrienyl complex: (C7H8)Mo(CO)3 + (C6H5)3C+ → + + (C6H5)3CHReduction of Mo(CO)6 gives 2− which is formally Mo(-II).CO-free Mo(0) compounds tend to be more reducing and kinetically labile than the carbonyl complexes. Examples include bis(benzene)molybdenum (Mo(C6H6)2) and tris(butadiene)molybdenum. Such compounds can be prepared by metal vapor synthesis and reductive routes from molybdenum(V) chloride.
Chemical cycling Summary Chemical_cycling Chemical cycling describes systems of repeated circulation of chemicals between other compounds, states and materials, and back to their original state, that occurs in space, and on many objects in space including the Earth. Active chemical cycling is known to occur in stars, many planets and natural satellites. Chemical cycling plays a large role in sustaining planetary atmospheres, liquids and biological processes and can greatly influence weather and climate. Some chemical cycles release renewable energy, others may give rise to complex chemical reactions, organic compounds and prebiotic chemistry.
Video game content rating system Computer Entertainment Rating Organization Video_game_content_rating_system > Rating systems > Japan > Computer Entertainment Rating Organization Formerly "12." C – Ages 15 and over. Formerly "15."
Møller-Plesset perturbation theory Original formulation Møller-Plesset_perturbation_theory > Møller–Plesset perturbation > Original formulation Clearly, through second-order in the correlation potential, the total electronic energy is given by the Hartree–Fock energy plus second-order MP correction: E ≈ EHF + EMP2. The solution of the zeroth-order MP equation (which by definition is the Hartree–Fock equation) gives the Hartree–Fock energy. The first non-vanishing perturbation correction beyond the Hartree–Fock treatment is the second-order energy.
Semantic memory History Semantic_memory > History The remembrance concept dealt with memories that contained experiences of an autobiographic index, whereas the memoria concept dealt with memories that did not reference experiences having an autobiographic index. Semantic memory reflects the knowledge of the world, and the term general knowledge is often used. It holds generic information that is more than likely acquired across various contexts and is used across different situations.
Metal fume fever Cause Metal_fume_fever > Cause Metal fume fever is due to the inhalation of certain metals, either as fine dust or most commonly as fumes. Simple metal compounds such as oxides are equally capable of causing it. The effects of particularly toxic compounds, such as nickel carbonyl, are not considered merely metal fume fever.Exposure usually arises through hot metalworking processes, such as smelting and casting of zinc alloys, welding of galvanized metals, brazing, or soldering. If the metal concerned is particularly high-risk, the residue from cold sanding processes may also cause fume fever, even if the dose is lower.
Thermodynamic operation Bibliography for citations Thermodynamic_operation > Bibliography for citations A translation may be found here. Also a mostly reliable translation is to be found at Kestin, J. (1976).
Non-CF bronchiectasis Summary Traction_bronchiectasis These secretions increase the amount of bacteria in the lungs, resulting in airway blockage and further breakdown of the airways. It is classified as an obstructive lung disease, along with chronic obstructive pulmonary disease and asthma. The diagnosis is suspected based on symptoms and confirmed using computed tomography.
Passive sign convention Alternative convention in power engineering Passive_sign_convention > Alternative convention in power engineering The power consumption or production of a component depends on its current–voltage characteristic curve. Whether the component acts as a source or load may depend on the current i or voltage v in it, which is not known until the circuit is analyzed.
AI safety Adversarial robustness AI_safety > Research foci > Robustness > Adversarial robustness (Left) is a correctly predicted sample, (center) perturbation applied magnified by 10x, (right) adversarial example.Adversarial robustness is often associated with security. Researchers demonstrated that an audio signal could be imperceptibly modified so that speech-to-text systems transcribe it to any message the attacker chooses.
CNC riveting Advantages CNC_riveting > Advantages Menu based navigation makes the programming fluid. High acceleration rate with high positioning accuracy. == References ==
Power dissipation Summary Power_dissipation In thermodynamics, dissipation is the result of an irreversible process that affects a thermodynamic system. In a dissipative process, energy (internal, bulk flow kinetic, or system potential) transforms from an initial form to a final form, where the capacity of the final form to do thermodynamic work is less than that of the initial form. For example, transfer of energy as heat is dissipative because it is a transfer of energy other than by thermodynamic work or by transfer of matter, and spreads previously concentrated energy. Following the second law of thermodynamics, in conduction and radiation from one body to another, the entropy varies with temperature (reduces the capacity of the combination of the two bodies to do work), but never decreases in an isolated system.
Gear shaper Summary Gear_shaper For external gears the number of teeth on the cutter is limited only by the size of the shaping machine. The principal motions involved in rotary gear shaper cutting are of the following: Cutting Stroke: The downward linear motion of the cutter spindle together with the cutter . Return Stroke: The upward linear travel of the spindle and cutter to withdraw the cutter to its starting position. Indexing Motion: Slow speed continuous rotation of the cutter spindle and work spindle to provide circular feed, the two speeds being regulated through the change gears such that against each rotation of the cutter the gear blank revolves through n/N revolution, where "n" is the number of teeth of the cutter, and "N" is the number of teeth to be cut on the blank. Completion of Cutting Operation: The indexing and reciprocating motions continue until the required number of teeth to the required depth are cut all along the periphery of the gear blank.
Kleene's recursion theorem Application to quines Kleene's_recursion_theorem > Kleene's second recursion theorem > Application to quines A classic example using the second recursion theorem is the function Q ( x , y ) = x {\displaystyle Q(x,y)=x} . The corresponding index p {\displaystyle p} in this case yields a computable function that outputs its own index when applied to any value. When expressed as computer programs, such indices are known as quines.
Regression (machine learning) Underlying assumptions Regression_prediction > Underlying assumptions Practitioners have developed a variety of methods to maintain some or all of these desirable properties in real-world settings, because these classical assumptions are unlikely to hold exactly. For example, modeling errors-in-variables can lead to reasonable estimates independent variables are measured with errors. Heteroscedasticity-consistent standard errors allow the variance of e i {\displaystyle e_{i}} to change across values of X i {\displaystyle X_{i}} .
Nomogram Summary Nomogram For example, to create larger nomograms for greater accuracy the nomographer usually includes only scale ranges that are reasonable and of interest to the problem. Many nomograms include other useful markings such as reference labels and colored regions. All of these provide useful guideposts to the user.
Bacterial motility Escape response Bacterial_motility > Bacterial taxis: Directed motion > Escape response Escape reactions are not strictly oriented—but commonly involve backward movement, sometimes with a negatively geotactic component. In bacteria and archaea, action potential-like phenomena have been observed in biofilms and also single cells such as cable bacteria. The archaeon Halobacterium salinarium shows a photophobic response characterized by a 180° reversal of its swimming direction induced by a reversal in the direction of flagellar rotation.
Integer sorting Practical algorithms Integer_sorting > Practical algorithms For this algorithm to work correctly, the sorting algorithm used in each pass over the data must be stable: items with equal digits should not change positions with each other. For greatest efficiency, the radix should be chosen to be near the number of data items, n. Additionally, using a power of two near n as the radix allows the keys for each pass to be computed quickly using only fast binary shift and mask operations. With these choices, and with pigeonhole sort or counting sort as the base algorithm, the radix sorting algorithm can sort n data items having keys in the range from 0 to K − 1 in time O(n logn K).
Gravitational field strength Orbital mechanics Newtonian_constant_of_gravitation > Value and uncertainty > Orbital mechanics In astrophysics, it is convenient to measure distances in parsecs (pc), velocities in kilometres per second (km/s) and masses in solar units M⊙. In these units, the gravitational constant is: For situations where tides are important, the relevant length scales are solar radii rather than parsecs. In these units, the gravitational constant is: In orbital mechanics, the period P of an object in circular orbit around a spherical object obeys where V is the volume inside the radius of the orbit.
Press fit Tightness of fit Press_fitting > Tightness of fit The tightness of fit is controlled by amount of interference; the allowance (planned difference from nominal size). Formulas exist to compute allowance that will result in various strengths of fit such as loose fit, light interference fit, and interference fit. The value of the allowance depends on which material is being used, how big the parts are, and what degree of tightness is desired. Such values have already been worked out in the past for many standard applications, and they are available to engineers in the form of tables, obviating the need for re-derivation.
HIV Replication and transcription HIV > Virology > Replication cycle > Replication and transcription The integration of the viral DNA into the host cell's genome is carried out by another viral enzyme called integrase.The integrated viral DNA may then lie dormant, in the latent stage of HIV infection. To actively produce the virus, certain cellular transcription factors need to be present, the most important of which is NF-κB (nuclear factor kappa B), which is upregulated when T cells become activated.
God Particle Popular science, mass media, and general coverage Introduction_to_the_Higgs_field > External links > Popular science, mass media, and general coverage Proceedings of the DPF-2011 Conference, Providence, RI, 8–13 August 2011". arXiv:1110.2253v1 ., and Guralnik, Gerald (2013). "Heretical Ideas that Provided the Cornerstone for the Standard Model of Particle Physics".
Tariff engineering Examples Tariff_engineering > Examples Columbia Sportswear uses so called "Nurse's Pockets", or small pockets near the waist line, on many of its women's shirt, including the PFG Tamiami, because women's shirts with pockets below the waistline are levied a lower import tariff than shirts without such pockets.Converse Chuck Taylor All-Stars sneakers have soles partially covered in a thin layer of felt when new, in order to be classified as slippers and pay a lower import tax duty than similar shoes. The layer usually rubs off within a month of being worn.
James Collins (bioengineer) Synthetic biology James_Collins_(bioengineer) > Work > Synthetic biology Recently, Collins developed freeze-dried, cell-free synthetic gene circuits, an innovative platform that forms the basis for inexpensive, paper-based diagnostic tests for emerging pathogens (e.g., Zika, Ebola, SARS-CoV-2, antibiotic-resistant bacteria), wearable biosensors, and portable biomolecular manufacturing (e.g., to produce vaccine antigens) in the developing world.In the context of synthetic biology and regenerative medicine, Collins collaborated with Derrick Rossi and George Q. Daley on a study using synthetic mRNA technology for biomedical applications. The team showed that synthetic mRNA could be used for highly efficient stem cell reprogramming and redifferentiation. This work was published in Cell Stem Cell in 2010, and Rossi used this synthetic biology technology platform to found Moderna.Collins has also used synthetic biology approaches (computational and experimental) to identify and address significant biological physics questions regarding the regulation of gene expression and cell dynamics. Collins, for example, has utilized synthetic gene networks to study the effects of positive feedback in genetic modules, the role and origin of stochastic fluctuations in eukaryotic gene expression, and the phenotypic consequences of gene expression noise and its effects on cell fate and microbial survival strategies in stressful environments. Importantly, Collins has also demonstrated how synthetic gene circuits can be used to test, validate and improve qualitative and quantitative models of gene regulation, and shown that biophysical theory and experiment can be coupled in bottom-up approaches to gain biological insights into the intricate processes of gene regulation.
Invariant basis number Properties Invariant_basis_number > Properties The main purpose of the invariant basis number condition is that free modules over an IBN ring satisfy an analogue of the dimension theorem for vector spaces: any two bases for a free module over an IBN ring have the same cardinality. Assuming the ultrafilter lemma (a strictly weaker form of the axiom of choice), this result is actually equivalent to the definition given here, and can be taken as an alternative definition. The rank of a free module Rn over an IBN ring R is defined to be the cardinality of the exponent m of any (and therefore every) R-module Rm isomorphic to Rn.
Gay-Lussac's law Law of combining volumes Gay-Lussac's_law > Law of combining volumes The law of combining volumes states that when gases chemically react together, they do so in amounts by volume which bear small whole-number ratios (the volumes calculated at standard temperature and pressure). The ratio between the volumes of the reactant gases and the gaseous products can be expressed in simple whole numbers. For example, Gay-Lussac found that two volumes of hydrogen and one volume of oxygen would react to form two volumes of gaseous water. Based on Gay-Lussac's results, Amedeo Avogadro hypothesized that, at the same temperature and pressure, equal volumes of gas contain equal numbers of molecules (Avogadro's law).
Relative angular momentum Angular momentum in orbital mechanics Relative_angular_momentum > Angular momentum in orbital mechanics {\displaystyle \mathbf {L} =m\mathbf {h} .} Mass is often unimportant in orbital mechanics calculations, because motion of a body is determined by gravity. The primary body of the system is often so much larger than any bodies in motion about it that the gravitational effect of the smaller bodies on it can be neglected; it maintains, in effect, constant velocity. The motion of all bodies is affected by its gravity in the same way, regardless of mass, and therefore all move approximately the same way under the same conditions.
Infrared non-destructive testing of materials Introduction to infrared thermography Infrared_non-destructive_testing_of_materials > Introduction to infrared thermography Infrared (IR) thermography is an analysis technique based on the detection of radiation in the IR part of the electromagnetic spectrum. According to the black body radiation law, all objects with temperature greater than absolute zero emit IR radiation. The device detecting and composing a 2D image of the IR radiation is generally called an IR camera or a thermographic camera, also referred to as an infrared camera. The result of the thermographic recording is an image or a sequence, which corresponds to the intensity of the thermal radiation of the recorded object.
Thermoelectric figure of merit Quality factor (detailed theory on semiconductors) Thermoelectric_power_factor > Thermoelectric figure of merit > Aspects of materials choice > Quality factor (detailed theory on semiconductors) For isotropic materials m b ∗ = m l ∗ {\displaystyle m_{\rm {b}}^{*}=m_{\rm {l}}^{*}} . Therefore, it is desirable for thermoelectric materials to have high valley degeneracy in a very sharp band structure. Other complex features of the electronic structure are important. These can be partially quantified using an electronic fitness function.
Passive transport Example of diffusion: Gas Exchange Passive_transport > Diffusion > Example of diffusion: Gas Exchange Cellular respiration is the cause of the low concentration of oxygen and high concentration of carbon dioxide within the blood which creates the concentration gradient. Because the gasses are small and uncharged, they are able to pass directly through the cell membrane without any special membrane proteins. No energy is required because the movement of the gasses follows Fick's first law and the second law of thermodynamics.