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57,717,760 | https://en.wikipedia.org/wiki/Armor%20Survivability%20Kit | The Armor Survivability Kit (ASK) is an armor kit developed by the U.S. Army Research Laboratory (ARL) in 2003 to protect vehicles like the Humvee from small arms, explosive device fragments, and rocket-propelled grenades (RPGs).
Armor
The Armor Survivability Kit consisted of armored steel doors with bullet-proof glass, protective armored plating, and a ballistic windshield and came in either a two-door kit variant (weighing 900 pounds/409 kilograms) or a four-door kit variant (weighing 1,300 pounds/590 kilograms).
History
The ASK was first produced in response to the lack of sufficient armor protecting Humvee vehicles and supply trucks during the war in Iraq and the rising number of deaths caused by improvised explosive devices (IEDs), sniper fire, and rocket-propelled grenade (RPGs).
The Humvee was not designed for active combat and as early as 1996 people inside the Pentagon had called for the army to develop a vehicle to protect soldiers.
Near the beginning of the Iraq war in 2003, the U.S. forces found themselves increasingly vulnerable to guerrilla attacks from roadside bombs and RPGs when driving in Humvees. By February 2004, more than 80 soldiers were killed by roadside bombs since the start of the war; soldiers improved armor but even that was not sufficient. U.S. troops had to rely on improvised vehicle armour and many soldiers resorted to jury-rigging scrap metal onto the doors of unprotected Humvees. At the same time military contractors in Iraq had protected vehicles like the Rhino Runner and the M1117, which had not been approved for procurement. The issue came to public attention when troops preparing to deploy to Iraq challenged Donald Rumsfeld as to why they had to resort to "hillbilly armor" scrounged from junk yards to protect themselves.
In response to the demand, Central Command’s Combined Joint Task Force 7 requested the Tank-Automotive and Armaments Command Research Development and Engineering Center (TARDEC) and ARL to develop a temporary armor kit to install onto unprotected Humvees until more armored vehicles could be shipped to Iraq. Within a week, the engineering team led by Michael J. Zoltoski created the designs for the ASK, which integrated ballistic metals, glass, and ceramics as well as polymers in order to withstand 7.62mm machine gun fire and IEDs.
In October 2003, less than 6 weeks after the initial design was created, 40 ASK prototypes were produced and field-tested at Aberdeen Proving Grounds in Maryland, after which they were ready to be shipped to Iraq along with two installers. By March 2004, 1,924 kits were shipped to Iraq and 1,636 kits were installed onto Humvee vehicles. That year, the Department of Defense rewarded ARL with an innovation award for the development of the ASK. By January 2005, more than 9,400 kits were reportedly delivered to soldiers in both Iraq and Afghanistan.
The ASK also served as a precursor to the development of the Fragmentary Armor or Frag Kits for armored vehicles in 2004.
While the introduction of ASKs onto unprotected Humvees did offer passengers more protection, other issues with the vehicle began to appear. The armor was still not sufficient to protect passengers from IEDs, which by that time were destroying even heavily armored vehicles. Also, due to the hot summer temperature in Iraq, occupants began to develop heat-related illnesses due to the heat buildup inside the vehicle. To resolve this problem, an air-conditioning system was installed inside many of the Humvees fitted with the ASKs. In addition, the additional weight brought on by the ASKs and other heavy armor plating increased the likelihood of the vehicle rolling over during serious accidents, which were sometimes fatal. From March 2003 through November 2005, an analysis of the U.S. Army’s ground-accident database found that 60 of the 85 soldiers who died in Humvee accidents in Iraq were killed when the vehicle rolled.
References
Explosion protection
Vehicle armour | Armor Survivability Kit | [
"Chemistry",
"Engineering"
] | 828 | [
"Explosion protection",
"Combustion engineering",
"Explosions"
] |
57,718,310 | https://en.wikipedia.org/wiki/Hymatic | Hymatic, also known as Hymatic Engineering, are a British manufacturer of heat exchangers, fluid control technology and cryogenic systems as part of an aircraft's environmental control system (ECS), headquartered in Worcestershire.
History
The company was founded on 27 September 1937.
It began making air compressors (pneumatics), anti-g valves, pressure reducing valves, stop valves and fuel system relief valves. Most well-known British aircraft in the 1950s and 1960s contained their valves and pneumatic equipment.
It developed the fuel system for Concorde. Concorde carried around 22,000 gallons of fuel. Concorde's fuel system had to overcome boiling of fuel at high altitudes.
In 2002, the company had a turnover of £21.7m.
Research
It has worked with the Cryogenic Engineering Group at the University of Oxford, in making linear compressors.
Ownership
The company was bought by Honeywell in February 2004, with the case referred to the Office of Fair Trading (OFT).
Structure
It is situated on the Moon's Moat Industrial Estate in Redditch. The company is registered with the British Cryogenics Council.
Products
Anti-ice valves
Cryocoolers for infrared sensors
Stored energy systems
References
External links
Grace's Guide
Crogenic Cooling Solutions
Aircraft component manufacturers of the United Kingdom
British companies established in 1937
Companies based in Redditch
Cryogenics
Honeywell
Manufacturing companies established in 1937
Science and technology in Worcestershire
Valve manufacturers | Hymatic | [
"Physics"
] | 299 | [
"Applied and interdisciplinary physics",
"Cryogenics"
] |
57,719,462 | https://en.wikipedia.org/wiki/NGC%201268 | NGC 1268 is a spiral galaxy located about 140 million light-years away in the constellation Perseus. It was discovered by astronomer Heinrich d'Arrest on February 14, 1863. NGC 1268 is a member of the Perseus Cluster and appears to show signs of distortion in the form of bridges. These features may be the result of a strong interaction with NGC 1267.
On August 30, 2008, a type Ia supernova designated as SN 2008fg was discovered in NGC 1268.
See also
List of NGC objects (1001–2000)
Eyes Galaxies
Mice Galaxies
References
External links
Perseus Cluster
Perseus (constellation)
Intermediate spiral galaxies
Interacting galaxies
1268
12332
2658
Astronomical objects discovered in 1863
Discoveries by Heinrich Louis d'Arrest | NGC 1268 | [
"Astronomy"
] | 156 | [
"Perseus (constellation)",
"Constellations"
] |
57,720,057 | https://en.wikipedia.org/wiki/Models%20of%20consciousness | Models of consciousness are used to illustrate and aid in understanding and explaining distinctive aspects of consciousness. Sometimes the models are labeled theories of consciousness. Anil Seth defines such models as those that relate brain phenomena such as fast irregular electrical activity and widespread brain activation to properties of consciousness such as qualia. Seth allows for different types of models including mathematical, logical, verbal and conceptual models.
Neuroscience
Neural correlates of consciousness
The Neural correlates of consciousness (NCC) formalism is used as a major step towards explaining consciousness. The NCC are defined to constitute the minimal set of neuronal events and mechanisms sufficient for a specific conscious percept, and consequently sufficient for consciousness. In this formalism, consciousness is viewed as a state-dependent property of some undefined complex, adaptive, and highly interconnected biological system.
Dehaene–Changeux model
The Dehaene–Changeux model (DCM), also known as the global neuronal workspace or the global cognitive workspace model is a computer model of the neural correlates of consciousness programmed as a neural network. Stanislas Dehaene and Jean-Pierre Changeux introduced this model in 1986. It is associated with Bernard Baars's Global workspace theory for consciousness.
Electromagnetic theories of consciousness
Electromagnetic theories of consciousness propose that consciousness can be understood as an electromagnetic phenomenon that occurs when a brain produces an electromagnetic field with specific characteristics. Some electromagnetic theories are also quantum mind theories of consciousness.
Orchestrated objective reduction
Orchestrated objective reduction (Orch-OR) model is based on the hypothesis that consciousness in the brain originates from quantum processes inside neurons, rather than from connections between neurons (the conventional view). The mechanism is held to be associated with molecular structures called microtubules. The hypothesis was advanced by Roger Penrose and Stuart Hameroff and has been the subject of extensive debate,
Thalamic reticular networking model of consciousness
Min proposed in a 2010 paper a Thalamic reticular networking model of consciousness. The model suggests consciousness as a "mental state embodied through TRN-modulated synchronization of thalamocortical networks". In this model the thalamic reticular nucleus (TRN) is suggested as ideally suited for controlling the entire cerebral network, and responsible (via GABAergic networking) for synchronization of neural activity.
Holographic models of consciousness
A number of researchers, most notably Karl Pribram and David Bohm, have proposed holographic models of consciousness as a way to explain number of problems of consciousness using the properties of hologram. A number of these theories overlap to some extent with quantum theories of mind.
Medicine
Clouding of consciousness
Clouding of consciousness, also known as brain fog or mental fog, is a term used in medicine denoting an abnormality in the regulation of the overall level of consciousness that is mild and less severe than a delirium. It is part of an overall model where there's regulation of the "overall level" of the consciousness of the brain and aspects responsible for "arousal" or "wakefulness" and awareness of oneself and of the environment.
Philosophy
Multiple drafts model
Daniel Dennett proposed a physicalist, information processing based multiple drafts model of consciousness described more fully in his 1991 book, Consciousness Explained.
Functionalism
Functionalism is a view in the theory of the mind. It states that mental states (beliefs, desires, being in pain, etc.) are constituted solely by their functional role – that is, they have causal relations to other mental states, numerous sensory inputs, and behavioral outputs.
Sociology
Sociology of human consciousness uses the theories and methodology of sociology to explain human consciousness. The theory and its models emphasize the importance of language, collective representations, self-conceptions, and self-reflectivity. It argues that the shape and feel of human consciousness is heavily social.
Spirituality
Eight-circuit model of consciousness
Timothy Leary introduced and Robert Anton Wilson and Antero Alli elaborated the Eight-circuit model of consciousness as hypothesis that "suggested eight periods [circuits] and twenty-four stages of neurological evolution".
References
Consciousness
Brain
Cognition
Cognitive architecture
Cognitive modeling
Cognitive neuroscience
Cognitive science
Cognitive science lists
Mental processes
Neuropsychology | Models of consciousness | [
"Engineering"
] | 854 | [
"Artificial intelligence engineering",
"Cognitive architecture"
] |
57,720,933 | https://en.wikipedia.org/wiki/Rachel%20Mills | Rachel Ann Mills is Professor of Ocean Chemistry and Senior Vice President (Academic) at King's College London. She is a deep-sea oceanographer who works on the chemistry of the seafloor and its impact on life in the sea. She has led research expeditions using submersibles and remotely operated vehicles to remote and deep unexplored parts of the ocean.
In the 2024 Birthday Honours, Rachel Mills was appointed a Commander of the Order of the British Empire (CBE) for services to marine science.
Early life and education
Mills studied oceanography at the University of Southampton, graduating in 1988. She completed her PhD on seafloor hydrothermal systems at the University of Cambridge.
Research and career
Mills remained as a postdoctoral researcher at the University of Cambridge until her appointment as a lecturer in Chemical Oceanography at the University of Southampton in 1993. She later held the positions of Head of Ocean and Earth Science at the National Oceanography Centre, Southampton and Dean of the Faculty of Natural and Environmental Sciences (now Faculty of Environmental and Life Sciences) at the University of Southampton. In 2021 she took up the role of Provost at the University of Sussex, subsequently moving to King's College London as Senior Vice President (Academic).
Mills works with biologists and microbiologists to understand how microbial and macrobiotic communities interact with seafloor mineral deposits. She used hydrothermal sediment geochemistry to understand past changes to Pacific Ocean ventilation during the Pleistocene. To evaluate carbon sequestration in the Southern Ocean, Mills uses sedimentary proxies of carbon cycling in the water column.
She is past-President of the Challenger Society for Marine Science, the UK’s learned society for oceanographers and other marine experts, which incorporates the UK Scientific Committee on Oceanic Research. Mills is the lead educator for a massive open online course with FutureLearn "Exploring Our Ocean". She was a founding member of the Natural Environment Research Council Training Advisory Board. She is part of the international collaborative research project GEOTRACES.
In 2018 she appeared on BBC Radio 4's The Life Scientific.
References
Living people
British geochemists
Women geochemists
20th-century British chemists
20th-century British women scientists
21st-century British chemists
21st-century British women scientists
Alumni of the University of Southampton
Alumni of the University of Cambridge
Academics of the University of Southampton
Year of birth missing (living people)
British oceanographers
Commanders of the Order of the British Empire | Rachel Mills | [
"Chemistry"
] | 495 | [
"Geochemists",
"British geochemists",
"Women geochemists"
] |
61,992,323 | https://en.wikipedia.org/wiki/Chandrasekhar%E2%80%93Page%20equations | Chandrasekhar–Page equations describe the wave function of the spin-1/2 massive particles, that resulted by seeking a separable solution to the Dirac equation in Kerr metric or Kerr–Newman metric. In 1976, Subrahmanyan Chandrasekhar showed that a separable solution can be obtained from the Dirac equation in Kerr metric. Later, Don Page extended this work to Kerr–Newman metric, that is applicable to charged black holes. In his paper, Page notices that N. Toop also derived his results independently, as informed to him by Chandrasekhar.
By assuming a normal mode decomposition of the form (with being a half integer and with the convention ) for the time and the azimuthal component of the spherical polar coordinates , Chandrasekhar showed that the four bispinor components of the wave function,
can be expressed as product of radial and angular functions. The separation of variables is effected for the functions , , and (with being the angular momentum per unit mass of the black hole) as in
Chandrasekhar–Page angular equations
The angular functions satisfy the coupled eigenvalue equations,
where is the particle's rest mass (measured in units so that it is the inverse of the Compton wavelength),
and . Eliminating between the foregoing two equations, one obtains
The function satisfies the adjoint equation, that can be obtained from the above equation by replacing with . The boundary conditions for these second-order differential equations are that (and ) be regular at and . The eigenvalue problem presented here in general requires numerical integrations for it to be solved. Explicit solutions are available for the case where .
Chandrasekhar–Page radial equations
The corresponding radial equations are given by
where is the black hole mass,
and Eliminating from the two equations, we obtain
The function satisfies the corresponding complex-conjugate equation.
Reduction to one-dimensional scattering problem
The problem of solving the radial functions for a particular eigenvalue of of the angular functions can be reduced to a problem of reflection and transmission as in one-dimensional Schrödinger equation; see also Regge–Wheeler–Zerilli equations. Particularly, we end up with the equations
where the Chandrasekhar–Page potentials are defined by
and , is the tortoise coordinate and . The functions are defined by , where
Unlike the Regge–Wheeler–Zerilli potentials, the Chandrasekhar–Page potentials do not vanish for , but has the behaviour
As a result, the corresponding asymptotic behaviours for as becomes
References
Spinors
Black holes
Ordinary differential equations | Chandrasekhar–Page equations | [
"Physics",
"Astronomy"
] | 532 | [
"Black holes",
"Physical phenomena",
"Physical quantities",
"Unsolved problems in physics",
"Astrophysics",
"Density",
"Stellar phenomena",
"Astronomical objects"
] |
61,992,967 | https://en.wikipedia.org/wiki/Mipartoxin-I | Mipartoxin-I is a neurotoxin produced by Micrurus mipartitus, a venomous coral snake distributed in Central and South America. This toxin causes a neuromuscular blockade by blocking the nicotinic acetylcholine receptor. It is the most abundant component in the venom.
Sources
The toxin is produced by the Micrurus mipartitus, also known as the ‘redtail coral snake’, ‘rabo de ají’, or ‘gargantilla’. The snake populates Nicaragua, Costa Rica, isthmus of Panama, Ecuador, Colombia, Venezuela and Brazil.
Chemistry
Structure and family
Mipartoxin-I is a short-chain, type-I, α-neurotoxin composed of 60 amino acids with a molecular mass of 7030 Da. It is a member of the three finger toxin (3FTx) superfamily, and it contains the characteristic eight cysteines of this superfamily.
Homology
CTX A5, a cardiotoxin from the cobra Naja atra, shows similarities with mipartoxin-I in the predicted core region and in amino acid sequence identity (38%). However, there are some slight differences in loop 1 and 2, and major differences in loop 3. Mipartoxin-I generally shows relatively low sequence similarity with other 3FTx family members.
Target
Mipartoxin-I is proposed to bind antagonistically to the nicotinic acetylcholine receptors and consequently inhibit the activity of this receptor without damaging the muscle fibres. The toxin blocks the muscle contractions without interfering with presynaptic acetylcholine release, indicating that it acts post-synaptically.
Toxicity
Envenoming mice with Mipartoxin-I causes bilateral ptosis and progressive respiratory paralysis. Following a decrease in activity and respiratory paralysis, mice die a few hours after envenoming. The LD50 of mipartoxin-I is 0.06 μg/g body weight.
Treatment
Currently, no specific antivenom is available in most of its important geographic field (Central America). The scarcity of an antivenom is complicated by insufficient cross-protection by antivenoms that are more accessible in this geographic area. However, the similarity in amino acid sequence of related toxins of two South American coral snakes were high (M. frontalis 70% and M. altirostris 68%). This indicates a possible cross-protection of these two antivenoms for mipartoxin-I.
References
Ion channel toxins
Neurotoxins
Snake toxins | Mipartoxin-I | [
"Chemistry"
] | 542 | [
"Neurochemistry",
"Neurotoxins"
] |
61,993,466 | https://en.wikipedia.org/wiki/NGC%201379 | NGC 1379 is a low-luminosity elliptical galaxy in the southern constellation Fornax. It was discovered by William Herschel on December 25, 1835.
At a distance of 60 million light-years, it is one of the closer members of the Fornax Cluster. It is located about 24' from the central galaxy, NGC 1399. NGC 1387 is the closest galaxy, and it is in the foreground of NGC 1379. Both are located in central part of the Fornax Cluster.
NGC 1379 has a Hubble classification of E0. It is also an early-type galaxy, like most other elliptical galaxies in the Fornax Cluster. Its size on the night sky is 2.6' x 2.5' which is, combined with the estimated distance, proportional to its real size of 50,000 light-years.
Despite their name, early-type galaxies are much older than spiral galaxies, and mostly comprise old, red-colored stars. Very little star formation occurs in these galaxies; the lack of star formation in elliptical galaxies appears to start at the center and then slowly propagates outward.
It is rich with globular cluster, with an estimated number of clusters of 406 ± 81. There are blue and red globular clusters, although red globulars are more populous than blue ones. This trend is also seen in NGC 1374, and in NGC 1387, which have only a small fraction of blue globular clusters. This galaxy has an almost equal number of red and blue. These globular clusters, like globulars in NGC 1374 and NGC 1387, do not show any evidence of multiple populations.
References
External links
Fornax Cluster
Elliptical galaxies
1379
Fornax
013299 | NGC 1379 | [
"Astronomy"
] | 365 | [
"Fornax",
"Constellations"
] |
61,995,184 | https://en.wikipedia.org/wiki/LNTX-1 | Long neurotoxin 1 (LNTX-1) is a neurotoxin that binds antagonistically to all types of muscular and neuronal nicotinic acetylcholine receptors. LNTX-1 is found in the venom of the king cobra (Ophioophagus hannah).
Etymology
LNTX-1 is an acronym for long neurotoxin 1. The “long” refers to the long-chain classification based on mature protein length of the neurotoxin, which is 66-79 amino acid residues long. There are more long neurotoxins found in snakes, such as LNTX-2 and LNTX-3.
Sources
LNTX-1 is produced by Ophioophagus hannah (king cobra), which is found in large parts of Asia. LNTX-1 is only one of the compounds of the cocktails of alpha-neurotoxins that this snake produces, making a venomous injection extremely lethal.
Chemistry
LNTX-1 belongs to the three-finger toxin family (3FTx) of snake venom toxins. The “three-finger” name refers to the fact that there are distinct three β-strand loops extending from the central globular core. The core of LNTX-1 is rich in disulphide bonds: it has ten conserved cysteine residues, which form five disulphide bridges. The 3FTx family consists of two major categories, neurotoxins and cardiotoxins. LNTX belongs to the neurotoxin family; other members include SNTXs (short chain neurotoxins), WNTXs (weak neurotoxins) and MTXs (muscarinic toxins). The particular 3FTx-subtype LNTX-1 falls within the long-chain subfamily and the type II α-neurotoxin sub-subfamily. The toxin targets both muscular and neuronal acetylcholine receptors. This dual action is attributed to its structure of eight conserved amino acid residues, Trp25, Asp27, Phe29, Arg33, Arg36, Phe65, Lys23 and Lys49. However, Lys23 and Lys49 residues are only required for muscular acetylcholine receptor binding.
Target and Mode of Action
LNTX-1 has a high affinity for the nicotinic acetylcholine receptor (nAChr) located at both the neuromuscular and neuronal junctions. Short chain toxins (see Chemistry) are only able to bind to the muscular nicotinic acetylcholine receptors, whereas long chain toxins can also bind to neuronal nicotinic acetylcholine receptors. The binding to the neuronal receptor is facilitated by the fifth disulphide bond of LNTX-1 (see Chemistry). This bond binds to the α-7-subunit to exert an inhibitory effect. The toxin behaves as an irreversible antagonist, occupying a binding site whereby acetylcholine would otherwise bind. The result of this antagonistic mode of inhibitory action by LNTX-1 is observed by decreased muscular and neuronal transmission. In addition, the toxin is also cytolytic, meaning that when the toxin has entered the bloodstream an osmotic imbalance between cells and their extracellular surrounding occurs, causing the cells to burst.
Toxicity
The LD50 of LNTX-1 is determined at 0,51 mg/kg by intravenous injection of the venom in mice. The IC50 value for LNTX-1 is 0,763 μM when the toxin is applied to human cells. The binding of LNTX-1 to the acetylcholine receptors leads to a loss of function in neuronal and neuromuscular transmission. The resulting symptoms include immobilization and asphyxiation which can be lethal to the subject that is infected by the toxin.
References
Ion channel toxins
Snake toxins
Neurotoxins | LNTX-1 | [
"Chemistry"
] | 859 | [
"Neurochemistry",
"Neurotoxins"
] |
61,995,510 | https://en.wikipedia.org/wiki/Triboracyclopropenyl | The triboracyclopropenyl fragment is a cyclic structural motif in boron chemistry, named for its geometric similarity to cyclopropene. In contrast to nonplanar borane clusters that exhibit higher coordination numbers at boron (e.g., through 3-center 2-electron bonds to bridging hydrides or cations), triboracyclopropenyl-type structures are rings of three boron atoms where substituents at each boron are also coplanar to the ring. Triboracyclopropenyl-containing compounds are extreme cases of inorganic aromaticity. They are the lightest and smallest cyclic structures known to display the bonding and magnetic properties that originate from fully delocalized electrons in orbitals of σ and π symmetry. Although three-membered rings of boron are frequently so highly strained as to be experimentally inaccessible, academic interest in their distinctive aromaticity and possible role as intermediates of borane pyrolysis motivated extensive computational studies by theoretical chemists. Beginning in the late 1980s with mass spectrometry work by Anderson et al. on all-boron clusters, experimental studies of triboracyclopropenyls were for decades exclusively limited to gas-phase investigations of the simplest rings (ions of B3). However, more recent work has stabilized the triboracyclopropenyl moiety via coordination to donor ligands or transition metals, dramatically expanding the scope of its chemistry.
Synthesis
For gas-phase spectroscopic studies, triboracyclopropenyl-containing compounds are obtained via laser ablation of boron targets and collimation of the resulting plasma cloud in a flow of inert carrier gas such as helium. The charged molecules of interest are then mass-selected by time-of-flight mass spectrometry. Addition of gases such as N2 or CO to the gas stream affords the corresponding adducts, while addition of metals such as iridium and vanadium to the B target yields the corresponding metal-doped clusters.
The sole isolable example of a triboracyclopropenyl anion that persists in solution and in the solid state was identified by Braunschweig and coworkers, who synthesized it by reducing the aminoborane Cl2B=NCy2 (Cy = cyclohexyl) with finely dispersed sodium metal in dimethoxyethane (DME). Cooling of the resulting orange-red solution of the dimeric species Na4[B3(NCy2)3]2 • 2 DME resulted in crystals suitable for X-ray diffraction, by which the structure was determined. Although the detailed reduction mechanism is unknown, it has been suggested that subvalent "R2N−B" intermediates are involved in the formation of such boron clusters.
Structure and bonding
Due to their special status as the simplest aromatic cycles, the electronic structure of triboracyclopropenyl derivatives has been analyzed with a variety of techniques in computational chemistry. These have ranged from canonical molecular orbital theory to alternative formulations of bonding such as adaptive natural density partitioning theory, the quantum theory of atoms in molecules, natural bond orbital theory, natural orbitals for chemical valence and electron localization function analysis. NICS and ring current calculations have also been used to characterize the aromaticity in such systems by using magnetic criteria. In general, the extremely small size of these cycles implies that their bonding electrons experience substantial Coulomb repulsion, resulting in abnormally high ring strain. This effect is partially compensated for by the stabilization offered by aromatic delocalization.
B3+
B3+ displays π aromaticity associated with its a2''-symmetric HOMO. In its singlet electronic ground state, it is a Hückel 2π electron system analogous to the cyclopropenium cation, but it is too reactive to be isolated. It is triangular, with D3h symmetry - all of its B atoms and B-B bond distances are chemically equivalent. The gas-phase adducts B3(N2)3+ and B3(CO)3+ have been computationally studied through ETS-NOCV (extended transition state - natural orbitals for chemical valence) theory, which dissects the changes in energy and electron density that result as a molecule is prepared from a reference state of noninteracting fragments. ETS-NOCV energy decomposition analysis suggests that the N2 and CO adducts are primarily stabilized (by -83.6 and -112.3 kcal/mol respectively) through σ donation of the exocyclic ligands into the highly electron-deficient boron ring. As a result, each was interpreted as a B3+ moiety supported by dative bonding from N2 or CO. The electron deformation density constructed from the NOCVs of this system, together with charges derived from natural bond orbital populations, indicate electron flow from the exocyclic ligand into the ring, which induces all the equivalent bonds of the B3+ core to shorten by approximately 4 pm. π-symmetry interactions are observed with both the weak σ donor N2 and the strong π acceptor ligand CO. However, the out-of-plane π backdonation (from the π system of the B3 ring to the π acceptor orbitals of each ligand) is less stabilizing than the in-plane π backdonation, with strengths of -26.7 and -19.6 kcal/mol for the [B3(CO)2+ + CO] system. This suggests that the minimum-energy configuration of the molecule is one which preserves maximal π aromaticity in the B3+ core.
Just as aromatic species like the cyclopentadienyl anion and the cyclopropenium cation can coordinate to transition metals, it was recently demonstrated that the B3+ ring can bind to metal centers. Laser ablation of a mixed B/Ir target produces two isomers of IrB3−, a B3+ ring coordinated to a formal Ir2- anion. These are a pseudo-planar η2 adduct and a tetrahedral η3 adduct, the latter of which contains an aromatic triboracyclopropenyl fragment. Both are nearly identical in energy and coexist in the generated cluster beam.
Computations suggest that B3+ may even bind inert noble-gas atoms to form an unusual family of compounds B3(Rg)3+ (Rg = rare/noble gas), with nonnegligible bond strengths (from 15 to 30 kcal/mol) that originate from Rg p-orbital σ donicity and a significant degree of charge transfer from Rg to B3+. The possibility of new noble-gas compounds that form exothermally and spontaneously is an opportunity for experimental work.
B3
B3 possesses a singly occupied a1' HOMO (a SOMO) that consists of σ-symmetric orbitals oriented toward the core of the ring, associated with σ delocalization and slightly shorter B-B bond lengths as compared to B3+. It is paramagnetic with a doublet ground state. It is nonpolar, flat and triangular, having D3h symmetry.
B3−
B3−, with a filled a1' HOMO in D3h symmetry, is considered to be "doubly" aromatic and relatively stable - it simultaneously possesses highly delocalized σ and π electrons in its HOMO and HOMO-1 respectively.
B3R32-
B3R32-, formulated with electron-sharing B−R bonds rather than dative arrows, is isoelectronic to B3+. 8 electrons are assigned to the triboracyclopenyl core, 6 in σ bonding orbitals and 2 in the π system, resulting in Hückel aromaticity. The only experimentally characterized compound of this class is Na4[B3(NCy2)3]2 • 2 DME, a dimer of stacked B3R32- units which are themselves aromatic. Natural bond orbital analysis indicates that this compound is highly stabilized (by roughly 45 kcal/mol) by a donor-acceptor interaction of localized B−B bond orbitals with corresponding B−N antibonding orbital across the ring, in addition to being bound together by electrostatic attraction to bridging Na+ cations identified in the crystal structure. DFT calculations show that the HOMO and HOMO-1 are antisymmetric and symmetric combinations of the π HOMO of an individual ring, respectively - a feature shared with metallocenes. As expected for a species with B−B bonds that have a formal MO bond order of , the average B-B bond length of 1.62 Å is closer to those of diborene (R-B=B-R) radical cations than B−B single bonds of roughly 1.75 Å.
Spectroscopy and spectrometry
Triboracyclopropenyl-derived compounds were first identified by their mass-to-charge ratio, as transient species in the mass spectrometry of complex mixtures of cationic boron clusters. Reactive scattering studies with O2 soon followed, revealing the relatively strong bonding within light boron clusters. Subsequently, B3 was isolated in matrices of frozen noble gases and electron paramagnetic resonance spectra were recorded which confirmed its D3h geometry. Hyperfine coupling of the unpaired electron to the 11B nucleus provided an estimate of 15% s-orbital character for the a1' HOMO. The small and nonpolar B3 rings were able to tumble and rotate freely even when confined in the matrix.
In general, triboracyclopropenyl-containing species have been too short-lived and produced in insufficient quantity for transmission-mode infrared spectroscopy. However, dissociating B3(N2)3+ with infrared light and observing the decay of the corresponding mass-to-charge signal via mass spectrometry allowed an effective infrared spectrum of B3(N2)3+ to be recorded. This vibrational photodissociation spectrum contained only a single detectable vibration with a redshift of 98 cm−1 relative to gaseous N2, suggesting a highly symmetric B3(N2)3+ adduct with slightly weakened N≡N bonding.
Negatively charged ions containing triboracyclopropenyl have proven amenable to study by photoelectron spectroscopy. By Koopman's theorem, neglecting the effects of strong electron correlation, the kinetic energies of electrons detached by X-rays can be mapped onto binding energies of individual orbitals and reveal the molecular electronic structure. Splitting of the resulting spectral peaks from "vibrational progression" (according to the Franck-Condon principle) indicates how ionization at different energies changes specific vibrational frequencies of the molecule, and such effects on bonding are interpreted in terms of changes to the electron configuration. In B3−, an unusually high-intensity and high energy band corresponding to a multielectron or "shake-up" transition (coupled electron detachment and electronic excitation) was observed, suggesting the strong electron correlation present in the triboracyclopropenyl fragment. For IrB3−, vibrational progression from the stretching and breathing vibrations of IrB3 could be assigned in the overlaid spectra of both isomers present in the cluster beam. By comparison to computations, the minimum energy structure of IrB3 could then be formulated as a tetrahedron with an intact, aromatic B3+ moiety.
Reactivity
The reactivity of triboracyclopropenyl-containing compounds is relatively under-explored, as only one example has been prepared in the solution phase. The compound reported by Braunschweig, Na4[B3(NCy2)3]2 • 2 DME, is an extremely potent reductant with an oxidation potential of -2.42 V vs. the ferrocene/ferrocenium couple. As a result, it is capable of reducing chloroboranes to afford tetrahedral B clusters, along with reducing PbCl2 directly to metallic Pb. In addition, it will undergo a ring-opening reaction at the B3 moiety by abstracting chlorine atoms from hexachloroethane. This level of reducing power is roughly comparable to an alkali metal, and has not been previously observed for any molecule based on an organic framework.
Although most examples of transition metal-doped trinuclear boron clusters do not contain an aromatic triboracyclopropenyl fragment, the reactivity of such species with small molecules is likely to attract increasing scientific interest. It has been demonstrated under the conditions of mass spectrometry that VB3+ dehydrogenates methane to afford the products VB3CH2+ and H2. A minor side reaction that produces VH+ and eliminates B3CH3 is also operative.
See also
Organoboron chemistry
Cyclopropenium ion
References
Boron compounds
Aromatic compounds
Hypothetical chemical compounds | Triboracyclopropenyl | [
"Chemistry"
] | 2,739 | [
"Aromatic compounds",
"Hypotheses in chemistry",
"Organic compounds",
"Theoretical chemistry",
"Hypothetical chemical compounds"
] |
61,995,864 | https://en.wikipedia.org/wiki/Apple%20speakers | Apple Inc. has produced and sold numerous music and multimedia speakers, available for standalone purchase and bundled with Macintosh products.
Plug-and-play speakers
Bose RoomMate speakers
In September 1986, Apple sold a special edition of the Bose RoomMate speakers for the Apple IIGS computer—which sports a built-in Ensoniq synthesizer chip with optional stereo sound. The front grille of each speaker had the Bose logo inside a black rectangle, and the official rainbow Apple logo in a square next to it. The speakers matched the platinum gray color scheme introduced with the IIGS that year. Later editions of the speakers, likely for legal issues pertaining to Apple Records, replaced the Apple-shaped logo with a rainbow-colored square, and eventually removed any Apple reference entirely. The powered speakers lacked a variable volume knob or magnetic shielding (a warning label stated to keep it distanced from the CRT and magnetic storage) and retailed for . Although primarily intended for the Apple IIGS which it cosmetically matched and better suited for its advanced audio capabilities, the speakers were also made available for early Macintosh models.
AppleDesign Powered Speakers
Along with the PowerCD introduced in 1993, Apple released two versions of their desktop speakers: the AppleDesign Powered Speakers (M6082) and the redesigned AppleDesign Powered Speakers II (M2497) a year later. The original speakers came in platinum gray to match Apple's desktop line, while the second generation were smaller, curvier and came in both platinum gray and a darker granite gray color designed to match the PowerBook line and PowerCD. Both were powered with an AC adapter and could be attached to any audio output source, with two separate inputs for the computer and an external CD player. Both had a headphone jack in the front of one speaker along with the volume control and an optional subwoofer connection port on some models.
G4 Cube speakers
Apple bundled a pair of model M7963 clear spherical/globe Sound Stick 2.1 based speakers with the Power Mac G4 Cube, which was released on July 19, 2000. They used a custom USB interface and originally worked with the G4 Cube, Power PCs and ADC/ADP monitor screens. They work right up to OSX 10.6.4 Snow Leopard. They were designed by Jonathan Ive & created in partnership with Harman Kardon, and were enlarged versions of the Odyssey speakers built in to the iMac G3.
Apple Pro Speakers
The Apple Pro Speakers were introduced in January 2001 alongside the Power Mac G4 Digital Audio, based on the G4 Cube's spherical speakers with a new digital audio system, plastic grilles, white rubber/silicone surrounds rather than the black foam used on the G4 cube speakers and changed the connector to a proprietary minijack that provided both power and audio. They were available as a standalone purchase for $59 and bundled with some versions of the iMac G4.
Harman Kardon SoundSticks and iSub
Apple announced the iSub in 1999, a 6-inch subwoofer produced in partnership with Harman Kardon, designed by Jony Ive. It uses clear plastic to match the aesthetic of the iMac G3. It connected over USB.
Next, Harman Kardon and Apple designed the SoundSticks, which were introduced at the 2000 Macworld expo. Apple led the industrial design and mechanical engineering to have them fit into its product family. They include a new revision of the iSub. They won an Industrial Design Excellence Awards gold award and were featured on the cover of I.D. magazine. SoundSticks II were a minor upgrade, adding capacitive volume control buttons and a 3.5mm mini-jack input, replacing the previous USB input. SoundSticks III changed the styling slightly using black highlights and white lighting, instead of green and blue of the original SoundSticks and the SoundSticks II. SoundSticks Wireless introduced Bluetooth.
iPod Hi-Fi
iPod Hi-Fi is a speaker system that was released on February 28, 2006, for use with any iPod digital music player. The iPod Hi-Fi retailed at the Apple Store for US$349 until its discontinuation on September 5, 2007. The iPod Hi-Fi received criticism due to its high price, lack of an AM/FM radio, and the limited functionality of its remote control.
Smart speakers
HomePod
The first-generation HomePod smart speaker was announced on June 5, 2017. It was sold in two colors: white and space gray. It had a small touchscreen on its top, seven tweeters in its base, and a four-inch woofer towards the top, as well as six microphones used for voice control and acoustic optimization; it also supports beamforming. It runs the audioOS operating system, which is based on iOS. The HomePod can act as a speaker and as a Siri voice assistant that listens for the "Hey Siri" command. The first-generation HomePod was discontinued on March 13, 2021. The second-generation was introduced on January 18, 2023.
HomePod Mini
HomePod Mini smart speaker was released on November 16, 2020. It is smaller than the HomePod, roughly spherical, and has three speakers and four microphones. Intercom, a new feature on HomePod and HomePod Mini introduced in iOS 14.1 and iPadOS 14.1, allows iPhone, iPad, and Apple Watch users with multiple HomePods and HomePod Minis to communicate between rooms using their voice. Siri recognizes up to six voices, and personalizes responses for each one.
See also
Timeline of Apple Inc. products
AirPods
Apple headphones
References
Apple Inc. peripherals
IPod accessories
IPhone accessories
Macintosh peripherals | Apple speakers | [
"Technology"
] | 1,174 | [
"IPhone accessories",
"Components"
] |
61,995,934 | https://en.wikipedia.org/wiki/Intrepicalcin | Intrepicalcin (ViCaTx1) is a short peptide toxin found in the venom of scorpion Vaejovis intrepidus. It is one of a group of short, basic peptides called calcins, which bind to ryanodine receptors (RyRs) and thereby trigger calcium release from the sarcoplasmic reticulum.
Etymology
The name intrepicalcin is a combination of the species name of the organism that produces it (Vaejovis intrepidus) and the family name of short toxins that it belongs to (calcins).
Source
Intrepicalcin is a toxin derived from the venom gland of the scorpion Vaejovis intrepidus . This species belongs to the family of Vaejovidae in the order of Scorpiones. Vaejovis intrepidus is endemic to central Mexico.
Chemistry
Structure and family
Intrepicalcin (ViCaTx1) belongs to the scorpion calcin family. The structure of calcins is specified by the Inhibitor Cystine Knot (ICK) motif. This folding motif is found in many toxins interacting with calcium channels in spiders and snails and distinguishes them from sodium, potassium and chloride channel toxins in scorpions. All calcins are composed of 33 amino acids, among which are 6 cysteines. These cysteines are highly conserved and form three disulfide bonds that are important for the ICK motif. In intrepicalcin and some other calcins, three of these cysteines are embedded in three 𝛽 strands.
The 3D structure of intrepicalcin has not yet been solved. However, the 3D structure of imperacalcin, another member of the calcin family, has been elucidated with 1H-NMR. Based on the fact that intrepicalcin and imperacalcin have a 70% sequence homology (see Homology), it is predicted that intrepicalcin has a coiled, spherical structure. The ICK motif contains three disulfide bridges embedded in 𝛽 strands. Most positively-charged residues (lysine and arginine) are located on the frontal side of the peptide. However, compared to other calcins, intrepicalcin contains two extra positively-charged basic lysines (residue 12 and 14) on its dorsal side. Therefore, its charge separation is the lowest of all calcins.
Homology
The most closely related calcin is vejocalcin, which only differs in its 14th residue (N in vejocalcin versus K in intrepicalcin) and has a matching identity of 97.0%. Imperacalcin, on the other hand, has a matching identity of only 69.7% (ten different residues) and has the lowest similarity with intrepicalcin of all currently known members of the calcin family. This suggests that within this family, intrepicalcin and imperacalcin have the smallest common evolutionary origin. Furthermore, in general the C-terminal part of the calcin peptide (residues 15-33), containing two of the cysteine-containing 𝛽 strands, is relatively conserved compared to the N-terminal part (residues 1-14). The C-terminal part thus also shows more homology across the calcin family than the N-terminal part.
Target
Intrepicalcin exerts its toxic effect by binding to ryanodine receptor 1 (RyR1), which is a calcium release ion channel present in mammalian skeletal muscle cells. RyR1s can be opened by direct protein-protein interaction with dihydropyridine receptors, which are voltage-sensing L-type calcium channels (CaV1.1). When the muscle depolarizes, a conformational change in CaV1.1 activates RyR1, which then opens and allows calcium release from the sarcoplasmic reticulum. This phenomenon is called coupled gating. RyR1s seem to be able to open without this interaction as well, but the underlying mechanism is not yet fully understood. RyR1 consists of four subunits and has binding sites for several regulatory molecules, such as calcium, calmodulin, ATP and magnesium. The opening of the channel involves two hinge glycines. The receptor is expressed in mammals, but homologues exist in avian and amphibian skeletal muscles.
Mode of action
Intrepicalcin stabilizes the opening of RyR1 and brings it into a reversible and long-lasting subconductance state. This subconductance state is 55% of the full conductance state of the channel and enables a constant calcium release from the sarcoplasmic reticulum. The precise binding site of intrepicalcin on RyR1 is not known. However, imperacalcin is known to bind a site within the ion conduction channel. Since all known calcins induce the same modifications, a common binding site seems likely. Intrepicalcin and calcins in general are able to cross the plasma membrane and can thus translocate between cells.
Toxicity
The ryanodine receptor 1 (RyR1) is expressed in skeletal muscles in mammals. The alterations in the calcium potentials which are caused by intrepicalcin interaction with RyR1, affect these skeletal muscles and result in muscular paralysis. This can contribute to the immobilization of the predators and preys of the scorpion Vaejovis intrepidus.
References
Neurotoxins
Ion channel toxins
Scorpion toxins
External links
UniProt Intrepicalcin | Intrepicalcin | [
"Chemistry"
] | 1,177 | [
"Neurochemistry",
"Neurotoxins"
] |
61,996,126 | https://en.wikipedia.org/wiki/MeuKTX | MeuKTX (α-KTx 3.13), which belongs to the α-KTx toxin subfamily, is a neurotoxin present in the venom of Mesobuthus eupeus. This short-chain peptide blocks potassium channels, such as Kv1.1, Kv1.2 and Kv1.3.
Etymology and source
MeuKTX is a neurotoxin found in the venom of the scorpion Mesobuthus eupeus which belongs to the family Buthidae. The M. eupeus is commonly found in the semi-arid and arid areas of China. The neurotoxin's name is an acronym in which the first three letters refer to the source of the venom (M. eupeus; lesser Asian scorpion) and the last three to its nature as a potassium channel toxin.
Chemistry
Structure
MeuKTX is a peptide chain of 37 amino acids forming three disulfide bridges, resulting in the molecular weight of 3987 Da. The amino acid sequence of MeuKTX is VGINVKCKHS GQCLKPCKDA GMRFGKCMNG KCDCTPK.
Homology
MeuKTX is an orthologue of BmKTX (α-KTx3.6) which is found in the closely related Mesobuthus martensii. These neurotoxins differ by a single amino acid at position 28 (Ile28Met).
Family
MeuKTX and BmKTX are members of the α-KTx subfamily which are evolutionarily conserved. Each member of this family consists of 23-42 amino acids with 3 or 4 disulfide bridges. These members share 68-97% sequence similarity and contain a specific sequence motif - AGMRFGKC. Typically, α-KTxs affect voltage-gated potassium channels.
Target
MeuKTX is a potent partial blocker for rat Kv1.1 (rKv1.1), rKv1.2, and human Kv1.3 (hKv1.3). The effectiveness of MeuKTX as a blocker for these potassium channels is summarized below:
Complete inhibition of ionic currents was observed at higher concentrations (2 μM) for all three potassium channels. At this concentration, MeuKTX also affects rKv1.6 and shaker IR channels.
Mode of action
The blocking effect of hKv1.3 by MeuKTX occurs rapidly and is reversible. Channel gating does not seem to be altered by binding of MeuKTX. However, the neurotoxin supposedly binds to the extracellular side of hKv1.3. Based on its relatedness to the α-KTx subfamily, it seems likely that a single toxin molecule occludes the extracellular pore.
Toxicity
In general, the M. eupeus scorpion venom has a lethal dose (LD50) of 4.5 (IV), 8.75 (IP), and 11.5 mg/kg (SC). Currently, there is no knowledge of the toxic effect of MeuKTX specifically. However it is suggested that MeuKTX blocks hKv1.3 on T lymphocytes and therefore suppresses immune responses.
Treatment
M. eupeus stings can only be effectively treated using antibodies against venom components.
References
Ion channel toxins
Scorpion toxins
Neurotoxins | MeuKTX | [
"Chemistry"
] | 721 | [
"Neurochemistry",
"Neurotoxins"
] |
61,997,982 | https://en.wikipedia.org/wiki/Discovery%20and%20development%20of%20bisphosphonates | Bisphosphonates are an important class of drugs originally commercialised in the mid to late 20th century. They are used for the treatment of osteoporosis and other bone disorders that cause bone fragility and diseases where bone resorption is excessive. Osteoporosis is common in post-menopausal women and patients in corticosteroid treatment where biphosphonates have been proven a valuable treatment and also used successfully against Paget's disease, myeloma, bone metastases and hypercalcemia. Bisphosphonates reduce breakdown of bones by inhibiting osteoclasts, they have a long history of use and today there are a few different types of bisphosphonate drugs on the market around the world.
Discovery
Bisphosphonates were originally synthesized in the 19th century and used in industry for their antiscaling and anticorrosive properties. In the late 1960s their potential to treat diseases related to the metabolism of the bones became evident. The first generation of bisphosphonates included etidronic acid and clodronic acid which were introduced in the 1970s and 1980s. They were the first bisphosphonate drugs to be used successfully in the clinic. They have since then been developed further with the intention to make them more potent, enhance their distribution inside the bone and extend the duration of action. This has made it possible to give zoledronate, the most recent bisphosphonate drug to be placed on the market, in a single annual dose by intravenous infusion.
Development
The original bisphosphonates (first generation) were simple molecules with small groups of single atoms or alkyl chains in position R1 and R2. They only had a rather weak inhibiting effect on bone resorption. The inclusion of an amino group marked the beginning of the second generation of bisphosphonates with higher potency. The first was pamidronate and similar analogues followed where the position of the nitrogen in the side chain was the key to a more potent drug. Later it became apparent that the nitrogen does not necessarily have to be connected to an alkyl chain but instead using a heterocyclic group. A few such drugs have been developed and placed on the market where zoledronate is the most notable one. Minodronic acid is even more potent and has been placed on the market in Japan. Their potency is such that it is effective even in picomolar concentration.
Further development has not resulted in the placing on the market of compounds in equal potency. Arylalkyl substitutes of pamidronate are among the most recent bisphosphonates to be used clinically where the hydroxyl group in position R2 has been omitted to ensure stability.
Recent research in this area has opened up an opportunity to develop new bisphosphonate drug therapies.
Bisphosphonates with a more lipophilic character have been developed and have shown potential as a tumor suppressant. They operate by a slightly different mechanism in which they not only inhibit the key enzyme farnesyl pyrophosphate synthase (FPPS) of the mevalonate pathway but also geranylgeranyl pyrophosphate synthase (GGPS), an enzyme also located in the mevalonate pathway. They do not have the same affinity for the bone minerals.
GGPS has since been successfully inhibited by a novel bisphosphonate compound with a triazole group within R2 and a methyl group in R1. This may become useful in therapies against malignancies like multiple myeloma.
In 2018, a dendritic bisphosphonate was introduced containing three bisphosphonate units. It has shown potential for bone specific delivery of large therapeutic molecules by taking advantage of the high affinity of bisphosphonates to the bone minerals
Mechanism of action
The mechanism of action of the bisphosphonates (BP's) has evolved as new generations of drugs have been developed. The function of the first generation bisphosphonates differs from the more recent nitrogen containing BP's but both are apparently internalised by endocytosis of a membrane-bound vesicle where the drug is most likely in a complex with Ca2+ ions. This does not concern other cells in the bone as this takes place by a selective uptake of osteoclasts.
The common function which applies to all bisphosphonate drugs is a physicochemical interaction with the bone mineral to prevent the physical resorption of the bone by the osteoclasts. This is especially relevant at sites where bone remodelling is most active. The bisphosphonates have an intrinsic affinity for the calcium ions (hydroxyapatite) of the bone mineral just as the endogenous pyrophosphates. The difference lies in the non-hydrolysable carbon-phosphorus bond of the bisphosphonates which prevents their metabolism and at the same time ensure an effective absorption from the gastrointestinal tract.
The primary inhibiting action of the first generation of bisphosphonates on osteoclasts is by inducing apoptosis. The mechanism of action is apparently by the formation of an ATP analogue or metabolite of the bisphosphonates like etidronic acid and clodronic acid. The ATP analogue accumulates in the cytosol of the osteoclast with a cytotoxic effect.
The primary mechanism of action of the more developed nitrogen containing bisphosphonates is however by cellular effects on osteoclasts through inhibition of the mevalonate pathway and in particular the subsequent formation of isoprenoid lipids. The inhibition takes place at a key branch point in the pathway catalyzed by farnesyl pyrophosphate synthase (FPPS). Isoprenoid lipids are necessary for post-translational modifications of small GTP-binding regulatory proteins like Rac, Rho and Ras of the Ras superfamily. The function of osteoclasts depends on them for a variety of cellular processes like apoptosis.
Structure activity relationship
Pharmacophore
Bisphosphonates mimic the endogenous inorganic pyrophosphate where the oxygen backbone is replaced with carbon (P-C-P for P-O-P). The two additional groups or side chains on the carbon backbone are usually referred to as R1 and R2. R1 is usually a hydroxyl group which enhances the affinity for the calcium by forming a tridentate ligand along with the phosphate groups. The compound can be made more potent by optimizing the structure of the R2 group to best inhibit bone resorption.
Phosphonate
Phosphonate groups in the chemical structure are important for the binding of the drug to the target enzyme. Studies have showed that removal or replacement of the phosphonate group with a carboxylic acid causes drastic loss in potency of the drug and the enzyme inhibitor no longer goes into an isomerized state.
Hydroxyl group (R1 side chain)
Modification of the R1 side chain on bisphosphonates is very minor today, single hydroxyl group at that position seems to give the best results in terms of activity. The hydroxyl group plays a role in forming a water-induced bond with glutamine (Gln240) on the target enzyme. Drugs that have no hydroxyl group initially cause better inhibition than parent compounds, without hydroxyl group the drug seems to fit more easily into the open active site. The absence of hydroxyl group however reduces the ability to hold the target enzyme complex in isomerized state. Biological activity of bisphosphonates with hydroxyl group, therefore, appears over longer time.
Nitrogen (R2 side chain)
Nitrogen containing bisphosphonates are the current most used drugs in the class because of their potency. Studies have showed that nitrogen on bisphosphonates forms hydrogen bond with threonine (Thr201) and the carbonyl part of Lysine (Lys200) on target enzyme, therefore enhancing the binding of the complex. Altering the position of nitrogen can significantly change the ability for the nitrogen hydrogen bond to occur.
Modification of nitrogen containing side chain (R2 side chain)
Increased carbon length of the nitrogen R2 side chain alters activity. Side chain that is made out of three carbons has proven to be the most ideal length in terms of activity, increasing or decreasing the length of the chain from there has negative effect on biological activity. Alendronate, a common bisphosphonate drug, has a three carbon length side chain for example. Risedronate has heterocyclic structure containing nitrogen. Heterocyclic nitrogen containing bisphosphonates have revealed better results in terms of activity compared to earlier bisphosphonates with nitrogen bound to carbon chain. Studies on risedronate analogous with different placement of nitrogen on the ring have shown no measurable difference on biological activity. Increased length of carbon chain connected to the ring revealed negative results. Zoledronate is the most potent bisphosphonate drug today only available as intravenous injection. It is the only bisphosphonate drug that has two nitrogen groups in the side chain hence its potency and route of administration differs from other drugs in the same class.
References
Drug discovery
Bisphosphonates | Discovery and development of bisphosphonates | [
"Chemistry",
"Biology"
] | 1,980 | [
"Life sciences industry",
"Medicinal chemistry",
"Drug discovery"
] |
61,998,158 | https://en.wikipedia.org/wiki/NGC%201406 | NGC 1406 is almost edge-on barred spiral galaxy in constellation Fornax. It was discovered by John Herschel on 18 November 1835.
It is a member of Fornax Cluster, a cluster of 200 galaxies. At a distance of 50 million light-years, it is one of the closest members of the Fornax cluster. NGC 1406 has a Hubble classification of SBbc, which indicates it is a barred spiral galaxy. It is also edge-on, making its bar hard to see. NGC 1406 has much dust in its disc, which is visible on the Hubble image in the box upper right.
Its size on night sky is 3.9' x 0.7' which is proportional to real size of 57,000 light-years. This means NGC 1406 is one of the larger galaxies in Fornax Cluster. It is north and distant from central galaxy NGC 1399, so it positions in the Fornax Cluster is at the edge of it.
References
External links
Barred spiral galaxies
Fornax Cluster
Astronomical objects discovered in 1835
1406
Fornax
013458 | NGC 1406 | [
"Astronomy"
] | 227 | [
"Fornax",
"Constellations"
] |
61,999,316 | https://en.wikipedia.org/wiki/Pyrogallolarenes | A pyrogallolarene (also calix[4]pyrogallolarene) is a macrocycle, or a cyclic oligomer, based on the condensation of pyrogallol (1,2,3-trihydroxybenzene) and an aldehyde. Pyrogallolarenes are a type of calixarene, and a subset of resorcinarenes that are substituted with a hydroxyl at the 2-position.
Pyrogallolarenes, like all resorcinarenes, form inclusion complexes with other molecules forming a host–guest complex. Pyrogallolarenes (like resorcinarenes) self-assemble into larger supramolecular structures forming a hydrogen-bonded hexamer. The pyrogallolarene hexamer is unique from those formed from resorcinarene, in that it does not incorporate solvent molecules into the structure. Both in the crystalline state and in organic solvents, six molecules will form an assembly with an internal volume of around one cubic nanometer (nanocapsules) and shapes similar to the Archimedean solids. A number of solvent or other molecules may reside in the capsule interior. The pyrogallolarene hexamer is generally more stable than the resorcinarene hexamer, even in polar solvents.
Synthesis
The pyrogallolarene macrocycle is typically prepared by condensation of pyrogallol and an aldehyde in concentrated acid solution in the presence of an alcohol solvent, usually methanol or ethanol. The reaction conditions can usually be carefully adjusted to precipitate the pure product or the product may be purified by recrystallization.
Pyrogallol[4]arene is simply made by mixing a solvent-free dispersion of isovaleraldehyde with pyrogallol, and a catalytic amount of p-toluenesulfonic acid, in a mortar and pestle.
References
Supramolecular chemistry
Macrocycles
Cyclophanes | Pyrogallolarenes | [
"Chemistry",
"Materials_science"
] | 438 | [
"Organic compounds",
"Macrocycles",
"nan",
"Nanotechnology",
"Supramolecular chemistry"
] |
62,001,712 | https://en.wikipedia.org/wiki/Saturn%20LX | Saturn LX, provisionally known as S/2004 S 29, is a natural satellite of Saturn and a member of the Gallic group. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and January 17, 2007. It was given its permanent designation in August 2021.
Saturn LX is about 4 kilometres in diameter, and orbits Saturn at an average distance of in , at an average inclination of 38.6° to the ecliptic, with an eccentricity of 0.485.
Saturn LX was initially thought to be part of the Inuit group before it was recategorized to the Gallic group in 2022.
References
Gallic group
Irregular satellites
Moons of Saturn
Discoveries by Scott S. Sheppard
Astronomical objects discovered in 2019
Moons with a prograde orbit | Saturn LX | [
"Astronomy"
] | 181 | [
"Astronomy stubs",
"Planetary science stubs"
] |
62,003,409 | https://en.wikipedia.org/wiki/Chinese%20missile%20warning%20system | The Chinese missile warning system is a national strategic defence asset being developed by China with assistance from Russia.
Chinese military efforts
China has been known to be developing a missile warning system since about 2014. The designation “JL-1A” has been associated with this system.
Russia’s involvement
On 3 October 2019, President Vladimir Putin said Russia is assisting China in developing the missile warning system. “We are now helping our Chinese partners to create a missile-warning system, a missile-attack warning system,” Putin said at the Valdai Club conference of foreign-policy experts in Sochi. “This is a very serious thing that will dramatically increase China’s defense capability, because only the US and Russia have such a system now.”
On 4 October 2019, Sergei Boyev, director general of Vympel NPO, a major weapons manufacturer in Russia, confirmed to Russia's state-run media that the company was working on "modelling" the system for China. Russia hopes to integrate China's early warning system with Russia's. This will provide China with an increased detection range from the North pole as well as the Atlantic and Pacific Ocean.
Russia operates the Voronezh radar system, which it continues to develop. This may be used as a basis for the Chinese system.
References
Military radars of the People's Republic of China
Military radar networks
Early warning systems
China–Russia relations | Chinese missile warning system | [
"Technology"
] | 284 | [
"Warning systems",
"Early warning systems"
] |
62,004,450 | https://en.wikipedia.org/wiki/Ring%20of%20modular%20forms | In mathematics, the ring of modular forms associated to a subgroup of the special linear group is the graded ring generated by the modular forms of . The study of rings of modular forms describes the algebraic structure of the space of modular forms.
Definition
Let be a subgroup of that is of finite index and let be the vector space of modular forms of weight . The ring of modular forms of is the graded ring .
Example
The ring of modular forms of the full modular group is freely generated by the Eisenstein series and . In other words, is isomorphic as a -algebra to , which is the polynomial ring of two variables over the complex numbers.
Properties
The ring of modular forms is a graded Lie algebra since the Lie bracket of modular forms and of respective weights and is a modular form of weight . A bracket can be defined for the -th derivative of modular forms and such a bracket is called a Rankin–Cohen bracket.
Congruence subgroups of SL(2, Z)
In 1973, Pierre Deligne and Michael Rapoport showed that the ring of modular forms is finitely generated when is a congruence subgroup of .
In 2003, Lev Borisov and Paul Gunnells showed that the ring of modular forms is generated in weight at most 3 when is the congruence subgroup of prime level in using the theory of toric modular forms. In 2014, Nadim Rustom extended the result of Borisov and Gunnells for to all levels and also demonstrated that the ring of modular forms for the congruence subgroup is generated in weight at most 6 for some levels .
In 2015, John Voight and David Zureick-Brown generalized these results: they proved that the graded ring of modular forms of even weight for any congruence subgroup of is generated in weight at most 6 with relations generated in weight at most 12. Building on this work, in 2016, Aaron Landesman, Peter Ruhm, and Robin Zhang showed that the same bounds hold for the full ring (all weights), with the improved bounds of 5 and 10 when has some nonzero odd weight modular form.
General Fuchsian groups
A Fuchsian group corresponds to the orbifold obtained from the quotient of the upper half-plane . By a stacky generalization of Riemann's existence theorem, there is a correspondence between the ring of modular forms of and a particular section ring closely related to the canonical ring of a stacky curve.
There is a general formula for the weights of generators and relations of rings of modular forms due to the work of Voight and Zureick-Brown and the work of Landesman, Ruhm, and Zhang.
Let be the stabilizer orders of the stacky points of the stacky curve (equivalently, the cusps of the orbifold ) associated to . If has no nonzero odd weight modular forms, then the ring of modular forms is generated in weight at most and has relations generated in weight at most . If has a nonzero odd weight modular form, then the ring of modular forms is generated in weight at most and has relations generated in weight at most .
Applications
In string theory and supersymmetric gauge theory, the algebraic structure of the ring of modular forms can be used to study the structure of the Higgs vacua of four-dimensional gauge theories with N = 1 supersymmetry. The stabilizers of superpotentials in N = 4 supersymmetric Yang–Mills theory are rings of modular forms of the congruence subgroup of .
References
Lie algebras
Modular forms
Number theory | Ring of modular forms | [
"Mathematics"
] | 730 | [
"Modular forms",
"Discrete mathematics",
"Number theory"
] |
62,920,366 | https://en.wikipedia.org/wiki/Treating%20%28dating%29 | In the social context of dating, treating is the practice of providing companionship and intimate activity in exchange for entertainment outings, gifts, and other items of monetary value. The activity was prevalent in the large urban areas of the United States from the 1890s to the 1940s and was most commonly engaged in by young working-class women. As treating became more widespread, the activity acquired the label "charity," and the young women who engaged in the more risqué aspects of the practice were often called charity girls.
Although some reformers in the early 20th century equated treating with prostitution, the young women who engaged in the activity strongly rejected this view and drew sharp distinctions between the two. As social dating between the sexes became more standard in the 1920s, treating began to blend with the system of dating and by the 1940s the specific language of treating had largely disappeared.
Etymology and usage
The word "treating" began as a political term with the practice of "providing" understood as a means to influence people and gain benefits. In modern usage, it is generally defined as the act of providing food, drink, and entertainment to an individual or a group free of charge. The word's use as a verb in a social context is believed to have originated in the male sphere of saloons when individuals would treat each other to another round of drinks. Around the turn of the nineteenth century, young working-class women who were seeking language for their interactions and bartering with young men adopted the word. Similar to the activity in the saloon, the practice of "to treat" evolved to mean the providing of something by a man to a woman, the women being the recipient of the "treat."
Origin
Treating came about with the birth of leisure time in the late nineteenth century. It emerged about the same time cheap amusements in cities gave working-class men and women opportunities to enjoy new aspects of city life away from cramped tenements and noisy, oppressive workplaces. For young women, the issue was how to afford the new entertainments, and one solution which materialized was treating.
In the late 19th century, inexpensive entertainment venues, such as public dance halls, amusement parks, and nickelodeon movie theaters, emerged and flourished in large American cities. At the same time, changing societal mores allowed more young women who previously had to be escorted in public more freedom to go out on their own or in same-sex groups. Although the cheap amusements were a major draw, going out for young working-class women still proved difficult due to their low wages, a portion of which was more often than not handed over to support the family. This lack-of-money issue was dealt with in various ways: some women refrained from going out altogether or limited going out to special occasions, while others depended on friends or their male counterparts to finance their entertainment pleasures. Inevitably, as more young women regularly went out, some found it necessary to depend on males for their entertainment and fun. As such, the practice of treating by young working-class women emerged.
Bartered exchange
The practice of treating ranged from the innocent bartered exchange to the more scandalous. It was seen as a harmless activity when conducted between a “steady” couple and more risqué when performed on a casual basis. Often the treating exchange was a tacit understanding with nuanced communication. However, even with little communication, young women well understood they were indebted to a certain extent to the men who treated. Like any interaction between a couple, whether tacit or not, sometimes it went smoothly with each party pleased with the outcome; other times, it did not. Occasionally, because men were sometimes tricked by women who skipped out after being provided a meal or an evening out, the exchange was more direct, for example a man asking directly what he would get in return. Unlike prostitution, in the treating exchange there was no guarantee the man would get what he wanted.
Young women who wanted more from the exchange—clothes, shoes, jewelry, or payment of bills—often engaged in the more risqué forms of treating. This may have involved, for example, being picked up from a dance hall or other venue and offering companionship for the evening, sometimes up to and including sexual favors. The women who engaged in the more risqué activities were referred to as charity girls. Cash was very rarely used in the treating transaction; that was considered an aspect of prostitution. The young women who engaged in treating did not see themselves as prostitutes, and, in fact, drew sharp distinctions between the two, but they often walked a fine line between being treated and being paid for their intimate activity.
Treating was predominantly practiced by young working-class women. It was seldom taken up by young women of middle- or upper-class means as members of those classes generally could afford their own entertainments. The activity was largely confined to the large urban areas of the United States as cities contained the entertainment venues and offered, as well, a degree of anonymity against prying family members and watchful neighbors. Treating differed from gold digging in that it was mainly a dating practice utilized to enjoy the entertainments and pleasures of city life and to acquire, perhaps, some desired personal items. To be sure, some women took "charity" a step further, but finding a wealthy man to marry, or becoming a mistress, was generally not the goal of the treating exchange.
Societal problem
As the practice of treating by young women became more widely known, it attracted the attention of reformers and vice squads who were alarmed by the activity. It was considered nothing less than outright prostitution by some. Entertainment venues, such as dance halls, where young men and women interacted came under close scrutiny. The taxi-dance halls where young women hostesses could be danced with for a modest sum per dance, usually ten cents, drew the particular ire of reformers, and some venues were shut down.
Treating in popular culture
The protagonist of the Broadway musical Sweet Charity, Charity Hope Valentine, was a taxi-dancer and likely charity girl. In the show, the title character is all too "charitable" but has a heart of gold. The musical was later adapted to the movie of the same name, directed by Bob Fosse.
In Truman Capote's Breakfast at Tiffany's, the dating activities of protagonist Holly Golightly closely resemble treating. She is not employed, so to support her New York City lifestyle she has to depend on gifts and assistance from the men in her life. In a March 1968 interview with Playboy, Capote asserted that Holly was not a prostitute and instead labeled her, and other young women like her, "authentic American geishas." He noted that "if [Holly] felt like it, she might take her escort home for the night." Capote, who wrote Breakfast at Tiffany's in the late 1950s, may not have realized the behavior he ascribed to Holly was previously known as treating, as by then the earlier language used to describe the activity had largely disappeared from the American vernacular. In 1961, the novella was adapted into the film of the same name, directed by Blake Edwards and featuring Audrey Hepburn as Holly.
See also
Casual sex
Enjo kōsai
Gold digging
Prostitution
Sugar dating
Transactional sex
Protective pairing
Further reading
McBee, Randy D. Dance Hall Days: Intimacy and Leisure among Working-Class Immigrants in the United States (New York: New York University Press, 2000)
Peiss, Kathy. Cheap Amusements: Working Women and Leisure in Turn-of-the-Century New York (Temple University Press, 1986)
Antonizzi, Barbara. The Wayward Woman: Progressivism, Prostitution, and Performance in the United States, 1888–1917 (Fairleigh Dickinson University Press, 2014)
References
1890s in the United States
1900s in the United States
1910s in the United States
1920s in the United States
1930s in the United States
1940s in the United States
Casual sex
Dating
Human sexuality
Prostitution in the United States
Sexuality and society
Underground culture
Working-class culture in the United States | Treating (dating) | [
"Biology"
] | 1,623 | [
"Human sexuality",
"Behavior",
"Human behavior",
"Sexuality"
] |
62,923,402 | https://en.wikipedia.org/wiki/Nokia%20Talkman%20520 | The Nokia Talkman 520 is a portable phone which is discontinued.
References
Talkman 520 | Nokia Talkman 520 | [
"Technology"
] | 19 | [
"Mobile technology stubs",
"Mobile phone stubs"
] |
62,923,466 | https://en.wikipedia.org/wiki/Nokia%20Talkman%20620 | The Nokia Talkman 620 is a portable phone which is discontinued.
Functions
Power signal received from the base station network
Keyboard and display lighting
Duration of the call (call)
Auto power off function
Volume control keyboard signals
Adjustable keyboard sound
Check the remaining battery
8Transmitter power control
Selection of country code
Set the block level
Transfer call to another handset
Pause
Memory
Multi-part transmission in the NMT system
Last number redial
Lock keypad
Clear Display
Select characters during conversation
Display angle settings
References
Talkman 620 | Nokia Talkman 620 | [
"Technology"
] | 102 | [
"Mobile technology stubs",
"Mobile phone stubs"
] |
62,923,581 | https://en.wikipedia.org/wiki/Mobira%20Talkman%20450 | The Mobira Talkman 450 is a brick phone which is discontinued.
References
Nokia mobile phones | Mobira Talkman 450 | [
"Technology"
] | 20 | [
"Mobile technology stubs",
"Mobile phone stubs"
] |
62,925,571 | https://en.wikipedia.org/wiki/Mobira%20Talkman%20900 | The Mobira Talkman 900 is a brick phone which is discontinued.
References
Nokia mobile phones | Mobira Talkman 900 | [
"Technology"
] | 20 | [] |
62,925,718 | https://en.wikipedia.org/wiki/Nokia%20Talkman%20510 | The Nokia Talkman 510 is a brick phone which has been discontinued. The phone is also known by the name 'Dataman'.
The term 'brick' has become popular for explaining phones of a solid, chunky form factor that more closely resembles a brick than a device, something that has become more defined with the evolution of the mobile phone. Such phones have also come to be colloquially known as 'dumbphones', a play on the term 'smartphone'.
References
Talkman 510 | Nokia Talkman 510 | [
"Technology"
] | 100 | [
"Mobile technology stubs",
"Mobile phone stubs"
] |
62,925,989 | https://en.wikipedia.org/wiki/Parallel%20task%20scheduling | Parallel task scheduling (also called parallel job scheduling or parallel processing scheduling) is an optimization problem in computer science and operations research. It is a variant of optimal job scheduling. In a general job scheduling problem, we are given n jobs J1, J2, ..., Jn of varying processing times, which need to be scheduled on m machines while trying to minimize the makespan - the total length of the schedule (that is, when all the jobs have finished processing). In the specific variant known as parallel-task scheduling, all machines are identical. Each job j has a length parameter pj and a size parameter qj, and it must run for exactly pj time-steps on exactly qj machines in parallel.
Veltman et al. and Drozdowski denote this problem by in the three-field notation introduced by Graham et al. P means that there are several identical machines running in parallel; sizej means that each job has a size parameter; Cmax means that the goal is to minimize the maximum completion time. Some authors use instead. Note that the problem of parallel-machines scheduling is a special case of parallel-task scheduling where for all j, that is, each job should run on a single machine.
The origins of this problem formulation can be traced back to 1960. For this problem, there exists no polynomial time approximation algorithm with a ratio smaller than unless .
Definition
There is a set of jobs, and identical machines. Each job has a processing time (also called the length of j), and requires the simultaneous use of machines during its execution (also called the size or the width of j).
A schedule assigns each job to a starting time and a set of machines to be processed on. A schedule is feasible if each processor executes at most one job at any given time.
The objective of the problem denoted by is to find a schedule with minimum length , also called the makespan of the schedule.
A sufficient condition for the feasibility of a schedule is the following
.
If this property is satisfied for all starting times, a feasible schedule can be generated by assigning free machines to the jobs at each time starting with time . Furthermore, the number of machine intervals used by jobs and idle intervals at each time step can be bounded by . Here a machine interval is a set of consecutive machines of maximal cardinality such that all machines in this set are processing the same job. A machine interval is completely specified by the index of its first and last machine. Therefore, it is possible to obtain a compact way of encoding the output with polynomial size.
Computational hardness
This problem is NP-hard even when there are only two machines and the sizes of all jobs are (i.e., each job needs to run only on a single machine). This special case, denoted by , is a variant of the partition problem, which is known to be NP-hard.
When the number of machines m is at most 3, that is: for the variants and , there exists a pseudo-polynomial time algorithm, which solves the problem exactly.
In contrast, when the number of machines is at least 4, that is: for the variants for any , the problem is also strongly NP-hard (this result improved a previous result showing strong NP-hardness for ).
If the number of machines is not bounded by a constant, then there can be no approximation algorithm with an approximation ratio smaller than unless . This holds even for the special case in which the processing time of all jobs is , since this special case is equivalent to the bin packing problem: each time-step corresponds to a bin, m is the bin size, each job corresponds to an item of size qj, and minimizing the makespan corresponds to minimizing the number of bins.
Variants
Several variants of this problem have been studied. The following variants also have been considered in combination with each other.
Contiguous jobs: In this variant, the machines have a fixed order . Instead of assigning the jobs to any subset , the jobs have to be assigned to a contiguous interval of machines. This problem corresponds to the problem formulation of the strip packing problem.
Multiple platforms: In this variant, the set of machines is partitioned into independent platforms. A scheduled job can only use the machines of one platform and is not allowed to span over multiple platforms when processed.
Moldable jobs: In this variant each job has a set of feasible machine-counts . For each count , the job can be processed on d machines in parallel, and in this case, its processing time will be . To schedule a job , an algorithm has to choose a machine count and assign j to a starting time and to machines during the time interval A usual assumption for this kind of problem is that the total workload of a job, which is defined as , is non-increasing for an increasing number of machines.
Release dates: In this variant, denoted by , not all jobs are available at time 0; each job j becomes available at a fixed and known time rj. It must be scheduled after that time.
Preemption: In this variant, denoted by , it is possible to interrupt jobs that are already running, and schedule other jobs that become available at that time.
Algorithms
The list scheduling algorithm by Garey and Graham has an absolute ratio , as pointed out by Turek et al. and Ludwig and Tiwari.
Feldmann, Sgall and Teng observed that the length of a non-preemptive schedule produced by the list scheduling algorithm is actually at most times the optimum preemptive makespan.
A polynomial-time approximation scheme (PTAS) for the case when the number of processors is constant, denoted by , was presented by Amoura et al. and Jansen et al.
Later, Jansen and Thöle found a PTAS for the case where the number of processors is polynomially bounded in the number of jobs.
In this algorithm, the number of machines appears polynomially in the time complexity of the algorithm.
Since, in general, the number of machines appears only in logarithmic in the size of the instance, this algorithm is a pseudo-polynomial time approximation scheme as well.
A -approximation was given by Jansen, which closes the gap to the lower bound of except for an arbitrarily small .
Differences between contiguous and non-contiguous jobs
Given an instance of the parallel task scheduling problem, the optimal makespan can differ depending on the constraint to the contiguity of the machines. If the jobs can be scheduled on non-contiguous machines, the optimal makespan can be smaller than in the case that they have to be scheduled on contiguous ones.
The difference between contiguous and non-contiguous schedules has been first demonstrated in 1992 on an instance with tasks, processors, , and .
Błądek et al. studied these so-called c/nc-differences and proved the following points:
For a c/nc-difference to arise, there must be at least three tasks with
For a c/nc-difference to arise, there must be at least three tasks with
For a c/nc-difference to arise, at least processors are required (and there exists an instance with a c/nc-difference with ).
For a c/nc-difference to arise, the non-contiguous schedule length must be at least
The maximal c/nc-difference is at least and at most
To decide whether there is an c/nc-difference in a given instance is NP-complete.
Furthermore, they proposed the following two conjectures, which remain unproven:
For a c/nc-difference to arise, at least tasks are required.
Related problems
There are related scheduling problems in which each job consists of several operations, which must be executed in sequence (rather than in parallel). These are the problems of open shop scheduling, flow shop scheduling and job shop scheduling.
References
Optimal scheduling
Packing problems | Parallel task scheduling | [
"Mathematics",
"Engineering"
] | 1,602 | [
"Optimal scheduling",
"Mathematical problems",
"Packing problems",
"Industrial engineering"
] |
62,926,986 | https://en.wikipedia.org/wiki/Centre%20for%20Industry%20Education%20Collaboration | The Centre for Industry Education Collaboration (CIEC) is a British education resource for information about the chemical industry in the UK.
History
The organisation was set up jointly by the Chemical Industries Association and the University of York in 1988 as the Chemical Industry Education Centre; it changed its name in 2014.
In June 2016 it won the Royal Society of Chemistry's Inspiration and Industry Award.
Function
Research has shown that the ages from 10–14 are when children lose interest in science; the organisation seeks to have up-to-date course material for secondary school teachers that can invigorate science teaching.
It organises visits for schools to local chemical companies.
Structure
It is headquartered in the Chemistry department of the University of York. It is a not-for-profit organisation, and is funded by companies in the British chemical industry. It has charitable status.
See also
BP Education Service
National Centre for Computing Education, also at the University of York
National Centre for Biotechnology Education, at the University of Reading
Science education in England
References
External links
CIEC
University of York
Primary school resources
1988 establishments in England
Charities based in North Yorkshire
Chemistry education in the United Kingdom
Chemistry organizations
Organisations based in York
Science and technology in North Yorkshire
Scientific organizations established in 1988
Departments of the University of York | Centre for Industry Education Collaboration | [
"Chemistry"
] | 253 | [
"Chemistry organization stubs",
"nan"
] |
62,929,551 | https://en.wikipedia.org/wiki/MiniZinc | MiniZinc is a constraint modelling language (or algebraic modeling language) to describe and solve high-complexity problems using a variety of well-known solving paradigms for combinatorial problems including constraint programming, integer programming, SAT, and SMT.
Following the constraint programming paradigm, in MiniZinc a problem is specified in terms of known values (parameters), unknown values (decision variables), and the relationship (constraints) between these values. MiniZinc promotes the use of global constraints to model well-known structures in problems. These global constraints improve the clarity of the model and allow solvers to use the most effective method to exploit the structure. A MiniZinc problem instance is translated (or flattened) to a level at which it only supports constraints that are supported by the target solver and then given to the solver using its preferred format. Currently MiniZinc can communicate with solvers using its own format FlatZinc or .nl files.
A big advantage of MiniZinc is the possibility to use different solvers, and even different solvers, from the same MiniZinc instance. MiniZinc supports many solvers, both open source and commercial software, including CBC, Choco, Chuffed, HiGHS, Gurobi, IPOPT, and OR-Tools.
MiniZinc is interoperable with other languages such as R and Python.
Language
The following MiniZinc model can be used to solve the famous n-queens puzzle:
include "all_different.mzn"; % Include all_different global
int: n = 8; % The number of queens. (parameter)
array [1..n] of var 1..n: q; % The height of the queens on the board. (decision variable)
% No queen can be in a position where it can capture another queen. (constraints)
constraint all_different(q);
constraint all_different(i in 1..n)(q[i] + i);
constraint all_different(i in 1..n)(q[i] - i);
References
External links
Numerical programming languages
Mathematical optimization software
Numerical software
Computer algebra systems
Mathematical modeling
Scripting languages
Text-oriented programming languages
Algebraic modeling languages
Supply chain analytics
Supply chain management | MiniZinc | [
"Mathematics"
] | 463 | [
"Computer algebra systems",
"Mathematical modeling",
"Applied mathematics",
"Numerical software",
"Mathematical software"
] |
62,931,555 | https://en.wikipedia.org/wiki/Dodo%20Sue%20Ware%20Kiln%20ruins | The is an archaeological site containing late Heian to early Kamakura period kilns located in the Mutsure neighborhood of the city of Tahara, Aichi in the Tōkai region of Japan. It was designated as a National Historic Site in 1922.
Overview
The Dodo Sue Ware Kiln was a Sue ware pottery production site approximately four kilometers southeast of the modern city center of Tahara, in a hilly forest. After World War II, many ruins of kilns have been discovered in the Atsumi Peninsula dating from the late Heian period to the early Kamakura period, thus shedding light on the origins of several styles of pottery which until that time were uncertain. The Dodo site contains two nobori-gama kilns built side-by-side on a hill, utilizing a south-facing slope. These kilns were used to produce everyday items, such as small bowls, plates, tea cups, etc.
The site is located approximately 18 minutes by car from Toyohashi Railroad Atsumi Line Mikawa-Tahara Station.
See also
List of Historic Sites of Japan (Aichi)
References
External links
Tahara Museum home page
History of Aichi Prefecture
Tahara, Aichi
Historic Sites of Japan
Japanese pottery kiln sites
Mikawa Province | Dodo Sue Ware Kiln ruins | [
"Chemistry",
"Engineering"
] | 264 | [
"Kilns",
"Japanese pottery kiln sites"
] |
62,935,696 | https://en.wikipedia.org/wiki/List%20of%20piezoelectric%20materials | This page lists properties of several commonly used piezoelectric materials.
Piezoelectric materials (PMs) can be broadly classified as either crystalline, ceramic, or polymeric. The most commonly produced piezoelectric ceramics are lead zirconate titanate (PZT), barium titanate, and lead titanate. Gallium nitride and zinc oxide can also be regarded as a ceramic due to their relatively wide band gaps. Semiconducting PMs offer features such as compatibility with integrated circuits and semiconductor devices. Inorganic ceramic PMs offer advantages over single crystals, including ease of fabrication into a variety of shapes and sizes not constrained crystallographic directions. Organic polymer PMs, such as PVDF, have low Young's modulus compared to inorganic PMs. Piezoelectric polymers (PVDF, 240 mV-m/N) possess higher piezoelectric stress constants (g33), an important parameter in sensors, than ceramics (PZT, 11 mV-m/N), which show that they can be better sensors than ceramics. Moreover, piezoelectric polymeric sensors and actuators, due to their processing flexibility, can be readily manufactured into large areas, and cut into a variety of shapes. In addition polymers also exhibit high strength, high impact resistance, low dielectric constant, low elastic stiffness, and low density, thereby a high voltage sensitivity which is a desirable characteristic along with low acoustic and mechanical impedance useful for medical and underwater applications.
Among PMs, PZT ceramics are popular as they have a high sensitivity, a high g33 value. They are however brittle. Furthermore, they show low Curie temperature, leading to constraints in terms of applications in harsh environmental conditions. However, promising is the integration of ceramic disks into industrial appliances moulded from plastic. This resulted in the development of PZT-polymer composites, and the feasible integration of functional PM composites on large scale, by simple thermal welding or by conforming processes. Several approaches towards lead-free ceramic PM have been reported, such as piezoelectric single crystals (langasite), and ferroelectric ceramics with a perovskite structure and bismuth layer-structured ferroelectrics (BLSF), which have been extensively researched. Also, several ferroelectrics with perovskite-structure (BaTiO3 [BT], (Bi1/2Na1/2) TiO3 [BNT], (Bi1/2K1/2) TiO3 [BKT], KNbO3 [KN], (K, Na) NbO3 [KNN]) have been investigated for their piezoelectric properties.
Key piezoelectric properties
The following table lists the following properties for piezoelectric materials
The piezoelectric coefficients (d33, d31, d15 etc.) measure the strain induced by an applied voltage (expressed as meters per volt). High dij coefficients indicate larger displacements which are needed for motoring transducer devices. The coefficient d33 measures deformation in the same direction (polarization axis) as the induced potential, whereas d31 describes the response when the force is applied perpendicular to the polarization axis. The d15 coefficient measures the response when the applied mechanical stress is due to shear deformation.
Relative permittivity (εr) is the ratio between the absolute permittivity of the piezoelectric material, ε, and the vacuum permittivity, ε0.
The electromechanical coupling factor k is an indicator of the effectiveness with which a piezoelectric material converts electrical energy into mechanical energy, or converts mechanical energy into electrical energy. The first subscript to k denotes the direction along which the electrodes are applied; the second denotes the direction along which the mechanical energy is applied, or developed.
The mechanical quality factor Qm is an important high-power property of piezoelectric ceramics. It is the inverse of the mechanical loss tan ϕ.
Table
References
Energy harvesting
Microelectronic and microelectromechanical systems
Piezoelectric materials | List of piezoelectric materials | [
"Physics",
"Materials_science",
"Engineering"
] | 861 | [
"Physical phenomena",
"Microtechnology",
"Materials science",
"Materials",
"Electrical phenomena",
"Piezoelectric materials",
"Microelectronic and microelectromechanical systems",
"Matter"
] |
51,541,792 | https://en.wikipedia.org/wiki/Rho%20Eridani | The Bayer designation ρ Eridani (Rho Eridani, ρ Eri) is shared by three stars in the constellation Eridanus that lie in a line:
ρ1 Eridani (8 Eridani)
ρ2 Eridani (9 Eridani)
ρ3 Eridani (10 Eridani)
Eridani, Rho
Eridanus (constellation) | Rho Eridani | [
"Astronomy"
] | 82 | [
"Eridanus (constellation)",
"Constellations"
] |
51,542,111 | https://en.wikipedia.org/wiki/Gamma%20Normae | The Bayer designation γ Normae, which is Latinized as Gamma Normae and abbreviated γ Nor, is shared by two stars in the southern constellation of Norma:
γ1 Normae, an F9 supergiant
γ2 Normae, a G8 giant
The pair form a double star that can be resolved with the naked eye.
References
Normae, Gamma
Norma (constellation) | Gamma Normae | [
"Astronomy"
] | 78 | [
"Norma (constellation)",
"Constellations"
] |
51,542,784 | https://en.wikipedia.org/wiki/Unnormalized%20form | In database normalization, unnormalized form (UNF or 0NF), also known as an unnormalized relation or non-first normal form (N1NF or NF2), is a database data model (organization of data in a database) which does not meet any of the conditions of database normalization defined by the relational model. Database systems which support unnormalized data are sometimes called non-relational or NoSQL databases. In the relational model, unnormalized relations can be considered the starting point for a process of normalization.
"Unnormalized form" should not be confused with denormalization, where normalization is deliberately compromised for selected tables in a relational database.
History
In 1970, E. F. Codd proposed the relational data model, now widely accepted as the standard data model. At that time, office automation was the major use of data storage systems, which resulted in the proposal of many UNF/NF2 data models like the Schek model, Jaeschke models (non-recursive and recursive algebra), and the nested table data model (NTD). IBM organized the first international workshop exclusively on this topic in 1987 which was held in Darmstadt, Germany. Moreover, a lot of research has been done and journals have been published to address the shortcomings of the relational model. Since the turn of the millennium, NoSQL databases have become popular owing to the demands of Web 2.0.
Relational form
Normalization to first normal form requires the initial data to be viewed as relations. In database systems relations are represented as tables. The relation view implies some constraints on the tables:
No duplicate rows. In practice, this is ensured by defining one or more columns as primary keys.
Rows do not have an intrinsic order. While tables have to be stored and presented in some order, this is unstable and implementation dependent. If a specific ordering needs to be represented, it has to be in the form of data, e.g. a "number" column.
Columns have unique names within the same table.
Each column has a domain (or data type) which defines the allowed values in the column.
All rows in a table have the same set of columns.
This definition does not preclude columns having sets or relations as values, e.g. nested tables. This is the major difference to first normal form.
NoSQL databases like document databases typically does not conform to the relational view. For example, an JSON or XML database might support duplicate records and intrinsic ordering. Such database can be described as non-relational. But there are also database models which support the relational view, but does not embrace first normal form. Such models are called non-first normal form relations (abbreviated NFR, N1NF or NF2).
Example with a table valued column
This table represent a relation where one of the columns (Transactions) is itself relation-valued. This is a valid relation but does not conform to first normal form which does not allow nested relations. The table is therefore unnormalized.
Modern applications
As of 2016, companies like Google, Amazon and Facebook deal with large amounts of data that are difficult to store efficiently. They use NoSQL databases, which are based on the principles of the unnormalized relational model, to deal with the storage issue. Some examples of NoSQL databases are MongoDB, Apache Cassandra and Redis.
See also
Denormalization
Normalization
First normal form
Second normal form
Third normal form
Boyce–Codd normal form
NoSQL
References
Data modeling | Unnormalized form | [
"Engineering"
] | 745 | [
"Data modeling",
"Data engineering"
] |
51,542,939 | https://en.wikipedia.org/wiki/Pine64 | Pine Store Limited, doing business as Pine64 (styled as PINE64), is a Hong Kong-based organization that designs, manufactures, and sells single-board computers, notebook computers, as well as smartwatch/smartphones. Its name was inspired by the mathematical constants and with a reference to 64-bit computing power.
History
Pine64 initially operated in Fremont, California, as Pine Microsystems Inc. It was founded by TL Lim, the inventor of the PopBox and Popcorn Hour series of media players sold under the Syabas and Cloud Media brands.
In 2015, Pine Microsystems offered its first product, the Pine A64, a single-board computer designed to compete with the popular Raspberry Pi in both power and price. The A64 was first funded through a Kickstarter crowdfunding drive in December 2015 which raised over US$1.7 million. The Kickstarter project was overshadowed by delays and shipping problems. The original Kickstarter page referred to Pine64 Inc. based in Delaware, but all devices for the Kickstarter campaign were manufactured and sold by Pine Microsystems Inc. based in Fremont, California.
In January 2020, Pine Microsystems Inc. was dissolved, while Pine Store Limited was incorporated on December 5, 2019, in Hong Kong. As of late 2020, the standard form contract of pine64.com binds all orders to the laws of Malaysia, while the products are shipped from warehouses in Shenzhen, China and Hong Kong.
Devices
After the initial Kickstarter orders for the Pine A64 single-board computers, the company went on to make more devices.
Single-board computers
The original Pine A64 boards released in 2016 are powered by the Allwinner A64 system-on-chip. It features a 1.2 GHz Quad-Core ARM Cortex-A53 64-Bit Processor, an ARM Mali 400 MP2 graphics processor unit, one HDMI 1.4a port, one MicroSD slot, two USB 2.0 ports and a 100 Megabit Ethernet port. The A64 board has only 512 megabytes of RAM, the 1 GiB and 2 GiB versions are labeled "Pine A64+". While the 512 MiB model only works with Arch Linux and Debian GNU/Linux distributions, such as Armbian or DietPi, the A64+ with more memory can also run other operating systems including Android, Remix OS, Windows 10, FreeBSD, and Ubuntu. Optional eMMC storage modules can be plugged into special headers on the board.
A compute module called SOPINE A64 was introduced in January 2017. It features the same system-on-chip as the Pine A64, but mounted on a DDR3 SODIMM form factor board without the USB, HDMI, and Ethernet connectors. It competes with the Raspberry Pi Compute Modules. Pine64 sells a "Clusterboard" with an inbuilt eight-port Gigabit Ethernet switch, which can be used to build a cluster system out of up to seven SOPINE modules. A review by Hackaday noted problems with production quality, software, and user support. 2017 also saw the addition of a "Long Term Supply" (LTS) version of the Pine A64/A64+ boards, called "Pine A64/A64(+)- LTS". The LTS versions are identical to the A64/A64+, but are guaranteed to be available until the year 2022 at a slightly higher cost.
In July 2017, the company added a new line of single-board computers based on Rockchip SoCs. The ROCK64 features a Rockchip RK3328 quad-core ARM Cortex-A53 64-bit processor; a Mali-450MP2 GPU capable of playing 4K HDR videos; one, two, or four gigabytes of RAM; two USB 2.0 and one USB 3.0 ports; one HDMI 2.0 port; a Gigabit Ethernet port; a microSD slot and several other peripheral ports. Its larger brother, the ROCKPro64, is based on a Rockchip RK3399 Hexa-Core (dual ARM Cortex-A72 and quad ARM Cortex A53) 64-Bit Processor instead. It features a Mali T-860 Quad-Core GPU and, in addition to the standard USB, Ethernet, HDMI, and MicroSD ports, also has an eDP interface and an open-ended PCI Express x4 slot. An optional PCI Express to Dual SATA-II adapter and an optional Wi-Fi module are offered by Pine64
In 2019, a new Allwinner-based board was added as a direct competitor to the Raspberry Pi 3 Model B+. The Pine H64 is based on the Allwinner H6 quad-core ARM Cortex-A53 64-bit processor. It features a Mali T-722 GPU, two or three gigabytes of RAM, two USB 2.0 and one USB 3.0 ports, one HDMI 2.0 port, onboard 802.11n Wi-Fi, a Gigabit Ethernet port, a microSD slot and several other peripheral ports. The Star64 is Pine64's first RISC-V SBC, based on the StarFive JH7110 SoC, launched in September 2022.
Notebook computers
In November 2016, the Pinebook, a netbook built around an Allwinner A64 SoC with 2 GiB of RAM and a 16 GiB eMMC module, was announced. Pre-release comments in Make wrote that the A64's closest analog was two to three times the A64's price, and that the A64 continued the Raspberry Pi's trend of breaking barriers for engineers.
Production started in April 2017. The Pinebook can only be obtained via a build-to-order system, potential buyers have to wait weeks or even months for an order code which then has to be redeemed within 72 hours. The hardware is priced at $99, but due to a $30 shipping fee and country-dependent import duties and taxes, the final price is higher. The Pinebook was notably used by the KDE team to improve Plasma on ARM desktops. In a review of the final hardware by Linux.com, the reviewer was surprised at his ability to have the full, albeit slow, Mate desktop environment at the A64's price. Phoronix's benchmarks indicated similar CPU performance to a Raspberry Pi 3.
In July 2019, the company announced the PineBook Pro, a netbook based around the Rockchip RK3399 SoC which is also used in the ROCKPro64. The pre-order system went live on July 25, 2019. The device was priced at $199, though the final price after shipping and import duties and taxes was higher. On March 15, 2020, it was announced that the PineBook Pro will ship with Arch Linux based Manjaro Linux as the default operating system.
Smartphone
, Pine64 is working on a Linux smartphone, PinePhone, using a quad-core ARM Cortex-A53 64-Bit System on a chip (SoC). The aim is for the phone to be compatible with any mainline Linux kernel and to "support existing and well established Linux-on-Phone projects", as a community-developed smartphone. After an initial BraveHeart release for early adopters in February 2020, the company continued releasing Community Editions that incrementally improve the design. The community support has been excellent, with 17 different OSes released for the device. In October 2021, the company announced the PinePhone Pro based on a binned RK3399 SoC with additional RAM and MMC storage, as well as higher resolution cameras.
Tablets
In May 2020, Pine64 announced the PineTab tablet, with an optional detachable backlit keyboard. It is a 10" tablet based on the same technology as the PinePhone, but without the modem and kill switches of that model. In August 2021, the company announced the PineNote. The PineNote is a 10" tablet with a Rockchip RK3566 and 4 GiB RAM, the same configuration used for the new Quartz64 SBCs. The tablet features a 227 DPI touchscreen Eink display panel that also includes a Wacom digitizer layer for stylus support. In December 2022, Pine64 announced the PineTab 2, intended to be a successor to the original PineTab, which was heavily impacted by shipping delays and component shortages.
Wearables
In 2019, Pine64 announced that it was working on a smartwatch. Only being available for developers initially, Pine64 released the PineTime in 2021, aimed at the consumer market. The PineTime display has a resolution of 240x240 with 65,536 colors. The device features 64 KiB of RAM, 512 KiB of flash storage, and 4 MiB of additional flash storage with Bluetooth 5.0 Low Energy for connectivity. The watch is powered by the Nordic Semiconductor nRF52832 SoC, with a 64 MHz ARM Cortex-M4F processor. The device was well received for its low cost to feature ratio. In early 2022, the company announced that it was working on a set of wireless earbuds. Pine64 later revealed the PineBuds, true wireless earbuds intended to run open-source firmware.
References
External links
2015 establishments in California
Computer companies established in 2015
Computer companies of Hong Kong
Computer hardware companies
Computer systems companies
Electronics companies of Hong Kong
Hong Kong brands
Kickstarter-funded products
Mobile phone manufacturers
Multinational companies headquartered in Hong Kong
Privately held companies of Hong Kong
Single-board computers | Pine64 | [
"Technology"
] | 2,006 | [
"Computer hardware companies",
"Computer systems companies",
"Computers",
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51,546,400 | https://en.wikipedia.org/wiki/Extrasynaptic%20NMDA%20receptor | Extrasynaptic NMDA receptors are glutamate-gated neurotransmitter receptors that are localized to non-synaptic sites on the neuronal cell surface. In contrast to synaptic NMDA receptors that promote acquired neuroprotection and synaptic plasticity, extrasynaptic NMDA receptors are coupled to activation of death-signaling pathways. Extrasynaptic NMDA receptors are responsible for initiating excitotoxicity and have been implicated in the etiology of neurodegenerative diseases, including stroke, Huntington’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis (ALS).
Extrasynaptic NMDA receptors form a death signaling complex with the transient receptor potential cation channel subfamily M member 4 (TRPM4). The NMDAR/TRPM4 complex is considered central to glutamate excitotoxicity. NMDAR/TRPM4 interaction interface inhibitors (also known as 'interface inhibitors') disrupt the NMDAR/TRPM4 complex thereby detoxifying extrasynaptic NMDA receptors. In mouse disease models, interface inhibitors protect against stroke induced brain damage and retinal ganglion cell degeneration.
References
Molecular neuroscience | Extrasynaptic NMDA receptor | [
"Chemistry"
] | 254 | [
"Molecular neuroscience",
"Molecular biology"
] |
51,547,415 | https://en.wikipedia.org/wiki/Interindividual%20differences%20in%20perception | Interindividual differences in perception describes the effect that differences in brain structure or factors such as culture, upbringing and environment have on the perception of humans.
Interindividual (differing from person to person) variability is usually regarded as a source of noise for research. However, in recent years, it has become an interesting source to study sensory mechanisms and understand human behavior. With the help of modern neuroimaging methods such as fMRI and EEG, individual differences in perception could be related to the underlying brain mechanisms. This has helped to explain differences in behavior and cognition across the population. The present study using MRS provides direct evidence showing that the excitatory process in the suprasensory areas is linked to the individual differences in visual motion perception. The neurotransmitter concentration in the higher areas that execute cognitive functions is related to the interindividual variability in the perception of visual motion. Common methods include studying the perception of illusions, as they can effectively demonstrate how different aspects such as culture, genetics and the environment can influence human behavior.
Optical Illusions
Bistable Motion
A motion quartet is a bistable stimulus - it consists of two dots that change their position from frame to frame. This position change can either be interpreted as horizontal or vertical movement by viewers, and this experience can switch during viewing between interpretations. Depending on the aspect ratio of the two dots' positions, one or the other state is perceived longer or more often. At an aspect ratio of one, the illusion is biased towards the vertical perception. The reason for this might be the way the human brain processes the signals from both eyes in the visual system. The right half of an eye's field of view is processed by the left hemisphere, and the left half by the right hemisphere. A stimulus moving vertically only involves one field of view and so one hemisphere, while a stimulus moving vertically from one field of view to the other involves both hemispheres, and requires communication between them. The delay caused by this additional signalling might be the cause for the bias. There are also individual differences in the way the motion quartet is perceived: Some people require a different aspect ratio to perceive both axes of movement than others.
A study using diffusion tensor imaging further showed differences in the structure of the corpus callosum, the primary connection between the two hemispheres, might be the origin of these differences.
Object size estimation
There exist a variety of illusions that make objects appear bigger or smaller compared to their real size. Two such illusions are the Ebbinghaus and the Ponzo illusions. The Ebbinghaus illusion makes a dot seem bigger because it is surrounded by smaller dots, while the Ponzo illusion exploits human perspective processing by making a dot appear bigger because it seems farther away. Schwarzkopf et al. found that the size of the primary visual cortex (V1) has an effect on the magnitude of these illusions. The larger the subject's V1 surface area was, the less the subjects fell for the illusion. This is hypothesized to be due to the fact that a larger V1 dedicated to the same portion of the visual field means a lesser effect of later, fixed-size visual areas (which are the ones that are responsible for the illusion effect).
Auditory Illusions
McGurk Effect
The McGurk effect is an auditory illusion in which people perceive a different syllable when incongruent audiovisual speech is presented: an auditory syllable "ba" is presented while the mouth movement is "ga". As a result, the listener perceives the syllable "da". However, according to Gentilucci and Cattaneo (2005), not everyone perceives this illusion; only about 26% to 98% of the population are susceptible to this illusion. One of the psychological models that explains the interindividual differences in speech perception is the fuzzy logic model of speech perception According to this model, a categorization process is carried out when processing speech sounds. When listening to a stimulus, the features of the acoustic signal are analyzed. Subsequently, this signal is compared with the features that are stored in the memory; finally the sound is classified into the category that best fits. However, this classification may have a blurred boundary respectively to the category which the sound belongs to. As a result, the final decision may depend on integration of multiple sources of information. When the McGurk effect is presented the auditory and visual components of the speech are separately evaluated before being integrated. In those who perceive the McGurk effect, the visual information has a higher influence on the perception of the ambiguous audiovisual information and thus the sound is classified as "da".
Many studies have concluded that the area responsible for the perception of this phenomenon is the left superior temporal sulcus(STS). This area is critical for the multisensory integration of visual and auditory information during speech perception. Moreover, there is a correlation between the activation of the STS and the perception of the McGurk effect. In that sense, if the left STS correctly integrates the mismatched audiovisual information, a McGurk effect is perceived; if the left STS is not active, the visual and auditory information are not integrated and thus a McGurk effect is not perceived.
In one study blood-oxygen-level dependent functional magnetic resonance imaging (BOLD fMRI) was used to measure the brain activity in perceivers and non-perceivers of the McGurk effect while presented with congruent audiovisual syllables, McGurk audiovisual syllables (auditory "ba" + visual "ga" producing perception of "da"), and non-McGurk incongruent syllables( auditory "ga" + visual "ba" producing auditory perception of "ga"). The researchers found that there was a positive correlation between the amplitude of response in the left STS and the probability of perceiving the McGurk effect. In other words, the subject with the weakest STS activation to incongruent speech had the smallest probability of experiencing a McGurk percept; whereas the subject with the strongest STS response had the highest probability.
Beauchamp et al. (2010) highlight the critical role of the left STS in audiovisual integration. They applied single pulses of transcranial magnetic stimulation (TMS) to the STS of McGurk perceivers during presentation of McGurk stimuli. The perception of the McGurk effect decreased from 94% to 43% and the subjects reported perceiving only the auditory syllable. Following from that, Beauchamp et al. conclude that the left STS is crucial for the audiovisual integration and thus for the perception of the McGurk effect.
Moreover, another study suggests that the basis of the interindividual differences in the perception of McGurk effect lies in the eye movements of the subject when viewing the talker's face. The experimenters carried out an eye tracking study and measured the eye movements of the participants while viewing audiovisual speech. They found that people who spent more time fixating the mouth of the talker were the more likely to perceive the McGurk effect than those who rarely fixated on the mouth of the speaker.
Other auditory illusions
Interindividual differences have also been researched for the Tritone paradox illusion. In this illusion, the subject successively listens to two tones, which are separated by a half octave. Each tone is made of a set of harmonics which have an octave relation. The listener has to decide if the two tones have a descending or ascending relation. According to Diana Deutsch, the perception of the tones is influenced by the language spoken by the listener. The listener has a circular representation of the pitch of sounds that are common in their culture and based on that develops a pitch range of their speaking voice, which determines the orientation of the pitch class with respect to the height; when a given tone is in this range, it is taken as the highest position along the circle and depending on the second tone, the person perceives the pattern as ascending or descending. Deutsch found that for people from California, the tone in the highest position of the pitch-class circle is around C# and D whereas for people from southern England it is around G. According to those results, Deutsch hypothesized that the orientation of the pitch-class circle with respect to the height is similar for individuals from the same linguistic group and varies for individuals from different linguistic groups.
Other illusions found by Deutsch whose interpretation depends on interindividual differences is the phantom words illusion. This illusion consists of the continuous presentation of two meaningless syllables. In order to experience the illusion, it is necessary that the listener sits between two loudspeakers, one to the left and the other to the right. The syllables are presented offset in time, in such a way that while one syllable is coming from the left, the other syllable is coming from the right loudspeaker. It was shown that after a period of time, people start hearing words. According to Deutsch, the perceived words depend on the language spoken by the listener, their knowledge and their expectations. According to Shinn-Cunningham (2008), when the information is incomplete or contradictory, the perceptual system often fills this gaps with plausible interpretations and in that way allows new information to be efficiently processed.
Effect of Culture on Perception
Several studies have shown that differences between individuals play a significant role in determining how a stimulus is perceived. These differences among people, in turn, are greatly influenced by one's own socio-cultural contexts. The research indicates that cultural factors influence the process of perception not just on lower-level (such as object perception and attention deployment), but also on the higher-order functions (such as theory of mind and emotion recognition).
The two major cultures analyzed in these studies were mostly Western and East Asian cultures because of the considerable differences in the social structure and practices. Western culture was referred to as an analytical culture whereas Eastern culture was referred more as a holistic culture. More specifically, individualism and freedom are the predominant values in Western societies, which in turn demand interpretation of an object in its absolute terms independent of its context. In contrast, Eastern culture is known for its emphasis on collectivism and interdependence on each other, where interpretation of an object is often in relation with its context
A pioneer study examining these cultural differences in visual perception was conducted by Kitayama et al. (2003). The findings of that study provide behavioural evidence on how cultural factors affect visual perception and attention deployment. For the study, Americans and Japanese were taken as subjects. The visual stimulus shown to the subjects consisted of a square figure with a line hanging from the centre (the framed line test). First was the absolute condition, where the task was to redraw the line on the centre of the square in its absolute length, to a new square box independent of its size. Second was the relative condition, in which the task was to redraw the line proportionally similar to context of the new square box. The results show that Americans perform better in the absolute task which requires analytical processing of stimulus independent of it context, whereas the Japanese performed better at the relative task which demands the holistic processing of the stimulus in relation to its context.
In line with these findings, Hedden and colleagues (2009) used the same visual stimuli to investigate the neural activity with the help of fMRI. Participants of the study were asked to judge the length of a vertical line, either including the contextual information or ignoring it. The results revealed that separate brain regions were employed while performing the task, either incorporating the contextual information or avoiding it, based on one's own culture. The areas associated with attentional control in the frontal and parietal region of the brain were highly activated when the subjects performed the task which was incongruent to their cultural pattern. That is, the activity in the fronto-parietal region enhanced when East Asians had to ignore the contextual information, while similar enhancement happened for Americans when they had to incorporate the contextual information. These findings illustrate that the function of the neural mechanisms are also modulated to some extent by one's own culture.
A follow-up fMRI study by Gutchess, Welsh, Boduroglu, and Park (2006) confirmed the previous findings by using a rather complex stimulus, which consists of only the object pictures, object with background pictures and only the background pictures without the object. This particular study was done on East-Asian Americans and non-Asian Americans. Though the performance of both subject groups was equally good, the activity of the involved brain areas was significantly different. Non-Asian Americans had a higher activation in the object processing areas in the ventral visual cortex during the object recognition task whereas the East-Asian Americans exhibited higher activity in the left occipital and fusiform areas which are associated with perceptual analysis.
References
Attention
Cognition
Cognitive neuroscience
Cognitive psychology
Cultural neuroscience
Cultural studies
Perception
Psychological anthropology | Interindividual differences in perception | [
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"Behavioural sciences",
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51,547,559 | https://en.wikipedia.org/wiki/Management%20of%20drug-resistant%20epilepsy | Drug-resistant epilepsy (DRE), also known as refractory epilepsy, intractable epilepsy, or pharmacoresistant epilepsy refers to a state in which an individual with a diagnosis of epilepsy is unresponsive to multiple first line therapies. Based on the 2010 guidelines from the International League against Epilepsy (ILAE), DRE is officially diagnosed following a lack of therapeutic relief in the form of continued seizure burden after trialing at least two antiepileptic drugs (AEDs) at the appropriate dosage and duration. The probability that the next medication will achieve seizure freedom drops with every failed AED. For example, after two failed AEDs, the probability that the third will achieve seizure freedom is around 4%. Drug-resistant epilepsy is commonly diagnosed after several years of uncontrolled seizures, however, in most cases, it is evident much earlier. Approximately 30% of people with epilepsy have a drug-resistant form. Achieving seizure control in DRE patients is critical as uncontrolled seizures can lead to irreversible damage to the brain, cognitive impairment, and increased risk for sudden unexpected death in epilepsy called SUDEP. Indirect consequences of DRE include seizure related injuries and/or accidents, impairment in daily life, adverse medication effects, increased co-morbidities especially psychological, and increased economic burden, etc.
Some clinical factors that are thought to be predictive of DRE include the female sex, focal epilepsy, developmental delay, status epilepticus, earlier age of onset of epilepsy, neurological deficits, having an abnormal EEG and/or imaging findings, genetic predisposition, association with the ABCB1 gene, and inborn errors of metabolism. Especially among pediatric populations there is a growing association between DRE and genetic conditions or developmental disorders such as Lennox-Gastaut or Dravet Syndrome.
There are numerous theories regarding the mechanism of action behind DRE many of which have been studied in human and/or animal models. However, it still remains unclear the exact pathogenesis of this condition.
Transporter Hypothesis: Changes to transporters in the blood-brain barrier lead to decreased effectiveness of AEDs through decreased drug concentration. These changes could be in the form of increased efflux transporters or less transporters overall.
Pharmacokinetic Hypothesis: Changes to transporters (increased efflux) peripherally in places like the intestines influence efficacy of AEDs and ability to ultimately reach target sites in the brain.
Target Hypothesis: Changes to target protein sites of AEDs influence their effectiveness.
Intrinsic Severity Hypothesis: Refers to the severity of epilepsy and impact increased seizure burden can have on drug efficacy.
Gene Variant Hypothesis: When AEDs are not as effective due to inherent genetic variability whether in transporters, target sites, and/or the specific kind of epilepsy.
Neural Network Hypothesis: When increased seizure burden impacts structure of the brain through neural connections which worsens clinical symptoms and reduces drug efficacy.
Diagnostic evaluation
The first step is for physicians to refer their DRE patients to an epilepsy specialist in a comprehensive epilepsy center where further diagnostic work-up can be performed.
Prolonged EEG/Continuous video EEG/ Epilepsy Monitoring Unit monitoring
One of the first steps in management of drug resistant epilepsy is confirming the diagnosis by EEG. Typically patients are admitted to hospital for prolonged EEG monitoring with video technology used to capture clinical events as they occur. Typically patients are taken off their anti-seizure medications in order to characterize the evolution of seizure symptoms and their relation with changes in electrical activity of brain. This is done while simultaneously minimizing the adverse consequences of seizures. Additional maneuvers to provoke seizures are also frequently performed, like sleep deprivation, photic stimulation, and hyperventilation. This study can take anywhere from 1–14 days. The length of the study depends on factors like baseline seizure frequency, the number and type of seizure medications the patient is taking prior to the study, institutional protocols etc. The goal is to record 3-4 typical seizures, though in some cases more or fewer seizures may need to be recorded. After this evaluation some patients may be determined to have non-epileptic causes of their symptoms, eg. syncope, psychogenic nonepileptic seizures, cardiac arrhythmia etc.
For patients who are confirmed to have epilepsy, this testing helps further elucidate the type of epilepsy (generalized vs focal), type of seizures (atonic, absence, GTC, etc.), and can be used for pre-surgical evaluation or to guide further management. Changes on EEG in relation to clinical seizure symptoms is used to determine the likely area of the brain responsible (symptomatic zone) and by extrapolation the area where seizure activity likely starts (seizure onset zone). In some specific cases, prolonged EEG may be done as an outpatient or ambulatory study where the patient goes home with an EEG set-up. This type of monitoring is usually limited to 2–3 days and patients are not taken off their AEDs.
Neuroimaging
MRI of brain is the most common first-line neuroimaging modality to be used in evaluation of a structural cause of epilepsy. A 3 Tesla MRI is generally recommended, as opposed to scanning on lower magnet strengths. MRI for evaluation of epilepsy often include T1 and T2 images that are optimized to appreciate gray-white matter differentiation and oblique coronal images along the axis of hippocampus. Identification of common lesions associated with epilepsy like focal cortical dysplasia, mesial temporal sclerosis, microencephalocele, and heterotopia require thorough review of images by trained clinicians as the changes can be very subtle and easily missed if not specifically evaluated for. Oftentimes, repeat MRI is required to elucidate an etiology to epilepsy and typically an epilepsy imaging protocol is followed to identify these subtle changes. There is ongoing quantitative analysis of standard MRI images to identify subtle lesions and use of stronger magnetic fields, like 7 Tesla MRI, for better delineation of anatomical details. Additionally, not all structural abnormalities seen on MRI correlate with epilepsy and may represent incidental findings.
Positron emission tomography scan (PET) using the 18F-FDG radiotracer can also be used in evaluation of DRE. Its use in epilepsy evaluation is based on the premise that areas of the brain responsible for seizure onset also have persistent metabolic dysfunction and do not use glucose at the same rate as neurotypical areas of the brain. Specifically, during seizure activity (ictal) one would expect a hypermetabolic state with increased radiotracer uptake on PET scan while in between events (interictal) one would expect a hypometabolic state with lower radiotracer uptake on PET scan. Oftentimes findings on PET scan are often correlated with other diagnostic workup that has already/concurrently been obtained to further localize an epileptogenic area of the brain, particularly in the case of focal epilepsy. Other ligands like 11C-flumazenil, 11C-alpha-methyl-L-tryptophan, 11C-methionine, have also been used, mostly on research basis to help identify areas of seizure onset.
Single-Photon Emission Computerized Tomography (SPECT scan) is another radiotracer based imaging technique that uses an oxygen radio-isotope to assess blood flow in the brain. This imaging is performed during inpatient video EEG monitoring in which the tracer is injected into the patient's bloodstream as soon as a seizure start. Areas of the brain associated with seizure onset will have increased blood flow, hence, increased uptake of the tracer if injected at an appropriate time. Imaging is performed after seizure activity is over to assess areas showing a significant increase in blood flow at seizure onset. A major limitation with this technique is the logistics required when injecting the radiotracer and quality of the images produced.
Magnetoencephalography (MEG): A newer non-invasive imaging technique that measures the magnetic field associated with neuronal firing in the brain. While each individual neuron's magnetic field is undetectable, when neurons are firing concurrently, such as during a seizure, the magnetic field generated is detected via MEG. This data provides real time brain mapping and has proven to be extremely effective in pre-surgical planning and localization of epilepsy. MEG is particularly useful in detect more superficial abnormalities and is more sensitive than other imaging modalities.
Neuropsychological testing
Neuropsychological testing involves a series of tests aimed at assessing higher order mental functions like memory, executive function, language, overall IQ, etc. in order to establish baseline cognitive function. If there is poor performance in measures of specific cognitive domains like verbal memory, naming, visual-spatial orientation; it may point to areas of brain that are dysfunctional and likely related to seizure onset. This testing could also indicate poor performance on most measures and suggest more widespread dysfunction in the brain. Besides helping assess the likely area of seizure onset, this testing can be informative post surgical intervention and/or epilepsy therapy.
Language Lateralization
If epilepsy surgery is being considered, testing is often performed to determine the hemisphere of the brain involved in language and memory function. This helps inform about potential risks to language and memory with surgery. There are two main tests available for this objective: the Wada test and fMRI.
The Wada test has been one of the most commonly used tests around the world since the 1960s. This is an invasive testing technique that requires neurointerventionalists, neuropsychologists, neurophysiologists, EEG technologists, and anesthesiologists. When conducting the wada test, a catheter is threaded from wrist or groin into the carotid artery and finally the middle cerebral artery. An injection of sodium amytal is given to temporarily anesthetize 2/3rd of the cerebral hemisphere on one side. Neuropsychological testing is then done to assess language and memory function of the other hemisphere. Once the patient is fully recovered from the injection on the first side, the catheter is withdrawn and threaded up the contralateral middle cerebral artery with neuropsychological testing repeated. This testing informs the "reserve" for memory and language function in each hemisphere and the potential for impairment with resective surgery on a given side. In some cases additional testing with selective injection of the posterior cerebral artery (that supplies the mesial temporal region including hippoampus) can be done.
The Wada test is increasingly being replaced by the noninvasive fMRI imaging technique. Functional MRI (fMRI) measures the change in blood flow and oxygenation in different parts of the brain in response to an activity. Different tasks or paradigms are presented to a patient while they are in an MRI scanner. These tasks are designed to activate areas involved in different language functions and post processing of the images helps identify areas that are activated during different language tasks.
Pharmacotherapy
While the term drug resistant epilepsy implies ineffectiveness of pharmacologic therapy, recent advances in the pharmaceutical industry have introduced new drugs that have proven to be effective in the management of DRE patients. Given the novel nature of these drugs, many of the sources utilized are primary/case studies.
Cenobamate
Approved by the FDA in 2019 for treatment of epilepsy in adults, Cenobamate is primarily used to treat patients with focal onset seizures. The mechanism of action of this drug is unclear, but is likely related to the inactivation of Na Channels and action as a GABA modulator. The dosing range for this drug is anywhere from 100-400 mg with a half-life of 55 hours. There have been at least three separate clinical trials involving Cenobamate with results showing a reduction in seizure burden by at least 50% in the experimental groups especially at higher doses of the drug. Of note, Cenobamate can interact with other medications especially other AEDs being taken and as such requires medication titration.
Fenfluramine
This drug was used at high doses as an obesity drug that was later recalled given adverse cardiac effects. Fenfluramine is now approved at lower doses as of 2020 for treatment of seizures in patients 2 years and older with Lennox-Gastaut and Dravet syndrome. Fenfluramine is an amphetamine derivative that acts as a serotonin agonist and on GABA and NMDA receptors. The dosing range is anywhere from 0.2-0.7 mg/kg/day with higher dosing being the most effective for seizure burden. Among Dravet and LGS patients, it has been shown to be helpful with most seizure types including atonic, GTC, and tonic. This medication has also been reported to be helpful in behavioral and cognitive symptoms associated with intractable epilepsy. In specific, at higher doses there are reports of patients showing improvement in daily executive functioning and emotional regulation. No adverse cardiac events have been reported with the use of fenfluramine for epilepsy treatment with the main side effects being diarrhea, weight loss, and fatigue.
Cannabidiol
Cannabidiol has recently been emerging as an effective treatment for epilepsy without the psychoactive effects of the Cannabis Sativa plant it is derived from. It gained approval in 2019 for treatment of DRE associated with Dravet, LGS, and more recently seizures associated with Tuberous Sclerosis in patients over the age of 2 years old. The mechanism of action of Cannabidiol is unclear but hypothesized to be related to Ca channels, adenosine signaling, and overall modulation of neuronal hyperexcitability. Cannabidiol is often used concurrently with another AED, especially clobazam, although there is evidence of the efficacy of Cannabidiol when used on its own. Some studies suggest the efficacy of Cannabidiol for all forms of DRE regardless of the underlying etiology. Similar to Fenfluramine, there has been evidence of improvements in cognition, emotional regulation, and communication in addition to seizure control for patients taking Cannabidiol.
Perampanel
First gained approval in the US in 2012 for the treatment of drug resistant focal epilepsy in patients 12 years and older. It is an antagonist at AMPA receptors with a dosing range from 4-12 mg/day. It is primarily used as an adjunctive treatment option and at higher doses is associated with adverse symptoms like dizziness, ataxias, and withdrawal symptoms. Perampanel has also been studied in the context of sleep and has been shown to help with sleep maintenance and reduction of daytime sleepiness.
Diets
For over 100 years it has been known that a diet with a high fat content and a low carbohydrate content can reduce seizures. Radically curbing carbohydrate intake imitates starvation and forces the body to draw energy from ketone bodies that form when fat is metabolized instead of drawing its energy from sugar. This state is called ketosis and it changes several biochemical processes in the brain in a way that inhibits epileptic activity. On this basis there are several diets that are often recommended to children under 12 years old, but are also effective in adults for DRE management.
Ketogenic diet
The ketogenic diet is the diet that is most commonly recommended by doctors for patients with epilepsy. In this diet the ratio of fat to carbohydrates and proteins is 4:1. That means that the fat content of the consumed food must be around 80%, the protein content must be around 15%, and the carbohydrate content must be around 5%. For comparison the average western diet consists of a carbohydrate content of over 50%. After one year on the ketogenic diet the success rate (seizure reduction over 50%) is between 30 and 50% and the dropout rate is around 45%. Although the ketogenic diet can be very effective, some families report that it's not compatible with daily life given its restrictive nature. It can be especially difficult for adolescents to follow as their autonomy increases. For this reason a fat ratio of 3: 1 instead of 4:1 can be recommended to make meals more palatable. Side effects of the ketogenic diet include constipation, fatigue, weight loss, and kidney stones (typically after long-term adherence).
MCT-Ketogenic diet
In the 1960s, it was discovered that when medium-chain triglycerides (MCT) are metabolized more ketone bodies are produced than from metabolizing any other fat. This discovery sparked the introduction of the MCT-ketogenic diet, a modification of the ketogenic diet. In the MCT-ketogenic diet, MCT oil is added to ketogenic meals, which allows the carbohydrate content to be increased. The efficacy of the MCT ketogenic diet does not differ significantly from the classic ketogenic diet however not all patients, especially pediatric populations, can tolerate the large amounts of MCT oil required. This diet can also be costly.
Modified Atkins
A modified Atkins diet was coined after the popular Atkins diet with the goal of reducing seizures through ketosis. In this diet, the fat content is slightly lower than in the ketogenic diet at around 60%, the protein content is around 30% and the carbohydrate content is around 10%. Several studies show that the modified Atkins diet is just as effective as the ketogenic diet. Some physicians recommend the modified Atkins diet because they assume that patients will adhere to it on the long-term because it is more compatible with daily life and the meals are more enjoyable.
Low Glycemic Index (LGI)
The aim of the LGI diet is to keep blood glucose levels at a stable state. Rapid fluctuations in glucose levels both high and low is thought to be a trigger for seizures in some patients with epilepsy. This diet permits 40-60 gram of carbohydrates daily but with the goal of a glycemic index of <50. This diet has been studied among pediatric populations as an effective form of management for DRE.
Surgery
In epilepsy surgery, a distinction can be made between resective and disconnective procedures. In a resective procedure the area of the brain that causes the seizures is removed. In a disconnective procedure the neural connections in the brain that allow the seizures to spread are disconnected. In most cases epilepsy surgery is only an option when the area of the brain that causes the seizures - the so-called epileptic focus can be clearly identified and is not responsible for critical functions such as language. Several imaging techniques such as magnetic resonance tomography and functional techniques like electrocorticography are used to demarcate the epileptic focus clearly. Recording fMRI and EEG simultaneously is a noninvasive method detecting cerebral hemodynamic changes related to interictal epileptic discharges (IEDs) on scalp EEG. This has been shown through different studies to help diagnose different types of epilepsy.
Lobe resection
Temporal lobe epilepsy (TLE) in which the epileptic focus is in the temporal lobe, is one of the most common types of epilepsy in adolescents and adults. Hence temporal lobe resection, during which the whole temporal lobe or just a part of the temporal lobe for example the hippocampus or the amygdala is removed, is the most common epilepsy surgery procedure. Between 40 and 60% of patients that undergo temporal lobe resection are continuously seizure free The surgery itself is very safe with a mortality of 0%. The risk for neurologic complications from a temporal lobe resection is around 3 to 7%
Lesionectomy
If the source of seizures is a lesion, for example a scar tissue from a brain injury a tumor or malformed blood vessels, this lesion can be removed surgically in a lesionectomy.
Corpus callosotomy
Corpus callosotomy is a palliative procedure for specially severe cases of epilepsy. This corpus callosum is a large bundle of nerve fibers that connects both brain halves with each other. To prevent the spreading of seizures from one brain hemisphere (brain half) to the other the corpus callosum can be split. This procedure is mostly carried out on patients with so-called drop attacks that come with a very high risk of injury and in which the epileptic focus is not clearly delimitable. It is very rare that a corpus callosotomy causes seizure freedom however in half of the patients the dangerous drop attacks are less severe. After a corpus callosotomy among others there is the risk that language is temporarily or permanently impaired. The younger a patient is at the time of the corpus callosotomy, the better the prognosis.
Functional hemispherectomy
This procedure is a modern adaptation of the radical hemispherectomy in which one brain hemisphere is removed to prevent the spread of seizures from one brain hemisphere to the other. In the functional version only a part of the hemisphere is removed but the connections to the other brain hemisphere are cut through. This procedure is only performed on a small group of patients under the age of 13 that have severe damage or malformation of one hemisphere, patients with Sturge Weber syndrome or patients with Rasmussen's encephalitis. Surgical intervention is considered a viable option for infants with drug-resistant epilepsy, particularly when anti-seizure medications fail to achieve seizure control. For this population, surgery can lead to favorable outcomes in a substantial number of cases. The functional hemispherectomy can achieve long-term seizure freedom in over 80% of patients however often at the price of hemiplegia and hemianopsy. The death rate is around 1 to 2% and 5% of patients develop a hydrocephalus that needs to be treated with a shunt.
Multiple subpial transection
Multiple subpial transection (MST) is a palliative procedure that is considered when an epileptic focus can be identified but cannot be removed because it is in a functionally relevant brain region- a so-called eloquent region. In an MST nerve fibers are disconnected so that seizures cannot spread from the epileptic focus into the rest of the brain. Between 60 and 70% of patients experienced a seizure reduction of over 95% after an MST and the risk for neurologic deficits is around 19%.
Vagus nerve stimulation
Vagus nerve stimulation (VNS) involves implanting a pacemaker-like generator below the skin in the chest area that intermittently sends electrical impulses to the left vagus nerve in the neck. The impulses are mediated to the brain by the vagus nerve and thereby help to inhibit electrical disturbances that cause seizures. The antiepileptic effect of vagus nerve stimulation increases over several months: after two years around half of VNS patients experience a reduction of their seizures by at least 50% and after 10 years the average seizure reduction is around 75% Furthermore, in most patients mood (VNS has a significant anti-depressent effect and is approved for depression in some countries), alertness and quality-of-life are increased significantly within the first year of vagus nerve stimulation. VNS patients can induce an extra stimulation themselves with a VNS magnet when they noticed that a seizure is approaching and it has been shown that the majority of seizures can be interrupted this type of on-demand stimulation.
The procedure to implant a vagus nerve stimulator is very safe: no case of death related to VNS implantation surgery has ever occurred. Infection of the tissue pocket in which the generator is located that requires antibiotic treatment occurs in around 3% of patients. The most common side effect is hoarseness or change in voice. Headaches and shortness of breath are less common. In most cases, side effects only occur during activity of the stimulation (mostly every 3 to 5 minutes) and reduce over time. In most cases VNS does not replace antiepileptic medication. Patients must continue their antiepileptic medication however in many cases the dose can be reduced over time so that patients experience fewer side effects of the medication. The battery of the VNS generator can, depending on the model and the settings, last between 3 and 10 years.
VNS with cardiac-based seizure detection
In 82% of epilepsy patients the heart rate increases quickly and suddenly upon a seizure This is known as ictal tachycardia. Ictal tachycardia is so characteristic that it can be distinguished from the slow gradual increase of heart rate that occurs during physical activity. This way in the majority of epilepsy patients seizures can be detected in the ECG. In addition to classical VNS, some new VNS generators continuously monitor heart rate and identify fast and sudden heart rate increases associated with seizures with intelligent software. Then an automatic additional stimulation can be triggered to interrupt, prevent or alleviate the seizure. This new generator type was shown to detect and treat at least four out of five seizures and 60% of seizures were shown to be interrupted with this heart-rate triggered stimulation. The earlier in the course of the seizure the stimulation occurred the quicker the seizure ended generally seizures were shown to be reduced by around 35% by stimulation
Other
Deep brain stimulation of the anterior nuclei of the thalamus is approved for DRE in some countries in Europe, but has been and continues to only be used in a very few patients. After 5 years of DBS a seizure reduction of 69% and a 50%-responder rate of 68% was reported in a randomized-double blinded trial. The rate of serious device related events was 34% in this study.
Responsive neurostimulation (RNS) is approved for DRE in the US and involves stimulation directly to 1 or 2 seizure foci when abnormal electrocorticographic activity is detected by the devices software. After 2 years of RNS a seizure reduction of 53% was reported in a randomized-double blinded trial as well as a rate of serious device related events of 2.5%.
Transcutaneous vagus nerve stimulation (tVNS) is approved for DRE in some European countries and involves externally stimulating the auricular branch of the vagus nerve in the ear. tVNS failed to demonstrate efficacy in a first randomized-double blinded trial: responder rates did not differ between active and control groups potentially indicating a placebo effect behind the 34% seizure reduction seen in the patients who completed the full follow-up period.
References
Epilepsy
Drug resistance | Management of drug-resistant epilepsy | [
"Chemistry"
] | 5,568 | [
"Pharmacology",
"Drug resistance"
] |
51,550,160 | https://en.wikipedia.org/wiki/Symmetry-adapted%20perturbation%20theory | Symmetry-adapted perturbation theory or SAPT is a methodology in electronic structure theory developed to describe non-covalent interactions between atoms and/or molecules. SAPT is a member of the family of methods known as energy decomposition analysis (EDA). Most EDA methods decompose a total interaction energy that is computed via a supermolecular approach, such that:
where is the total interaction energy obtained via subtracting isolated monomer energies and from the dimer energy . A key deficiency of the supermolecular interaction energy is that it is susceptible to basis set superposition error (BSSE).
The major difference between SAPT and supermolecular EDA methods is that, as the name suggests, SAPT computes the interaction energy directly via a perturbative approach. One consequence of capturing the total interaction energy as a perturbation to the total system energy rather than using the subtractive supermolecular method outlined above, is that the interaction energy is made free of BSSE in a natural way.
Being a perturbation expansion, SAPT also provides insight into the contributing components to the interaction energy. The lowest-order expansion at which all interaction energy components are obtained is second-order in the intermolecular perturbation. The simplest such SAPT approach is called SAPT0 because it neglects intramolecular correlation effects (i.e., it is based on Hartree–Fock densities). SAPT0 captures the classical electrostatic interaction of two charge densities and exchange (or Pauli repulsion) at first-order, and at second-order the terms for electrostatic induction (the polarization of the molecular orbitals in the electric field of the interacting atom/molecule) and dispersion (see London dispersion) appear, along with their exchange counterparts.
Higher terms in the perturbation series can be accounted for using many-body perturbation theory or coupled-cluster approaches. Alternatively, density functional theory variants of SAPT have been formulated. The higher-level SAPT methods approach supermolecular coupled-cluster singles, doubles, and perturbative triples [CCSD(T)] in accuracy.
References
Molecular physics
Quantum chemistry
Physical chemistry
Electronic structure methods | Symmetry-adapted perturbation theory | [
"Physics",
"Chemistry"
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51,550,201 | https://en.wikipedia.org/wiki/Effects%20of%20overtime | Employees who work overtime hours experience numerous mental, physical, and social effects. In a landmark study, the World Health Organization and the International Labour Organization estimated that over 745,000 people died from ischemic heart disease or stroke in 2016 as a result of having worked 55 hours or more per week. Significant effects include stress, lack of free time, poor work-life balance, and health risks. Employee performance levels could also be lowered. Long work hours could lead to tiredness, fatigue, and lack of attentiveness. As a result, suggestions have been proposed for risk mitigation.
Health and safety
The health and safety effects of overtime work vary widely and much remains unknown. Some studies have reported numerous adverse health effects, including increased alcohol and tobacco usage, decreased birthweight in offspring, and decreased cognitive functioning found both subjectively and objectively using specialized testing. However, other studies have not established such relationships between overtime work and decreased health. Work shifts lasting 9–12 hours, work shifts exceeding 12 hours, and work weeks exceeding 40 hours have each demonstrated—in some studies—varying levels of decreased cognitive testing performance and increased workplace injury. Inconsistencies between studies may be secondary to numerous workplace and employee factors, which make it difficult for researchers to establish specific causal relationships. A larger amount of data exist regarding the male workforce, whereas additional studies are needed to better assess impacts of overtime work and extended shifts on women. A survey about events between 1987 and 2000 found that in a cohort of 10,793 men and women, overtime work was associated with a 61% excess rate of injury compared to jobs without overtime. Injury rate was directly proportional to length of the work shift and number of hours in the work week. Study authors found excess injury risk not only associated with jobs that are more hazardous, but also with overall fatigue from working overtime and extended work shifts.
Mental effects
The mental effects on workers will vary based upon the work they do, the number of hours they work, and the individual working. Groupon performed a study in July 2016 on the effects of work. The results found that 38% work too much, 46% never had time to relax, and 60% of pollers have an unhealthy work-life balance. While this research showed some trends concerning the effects, other research has been performed to test the satisfaction levels of employees. A 2004 study of workers in Australia showed a trend that satisfaction levels decreased as the number of hours worked increased. They also stated that these effects could be lessened for those who enjoyed working extensive hours. These types of workers are more satisfied with their work-life balance.
In addition to working satisfaction, another Australian longitudinal cohort study revealed poorer mental health in workers with long working hours. The authors conducted a 12-year longitudinal follow-up cohort consisting of 18,420 people and 90,637 observations. With the Mental Component Summary (MCS) of the Short Form 36 (SF-36) measure, they noted a 48% increased probability regarding mental health decline in those workers working 49–59 hours per week, compared with those under standard working hours (that is, 35–40 hours per week). The probability increased by 53% in those working more than 60 hours a week. They also found a difference by gender; among those working 49–59 hours per week, the SF-36 scores are lower among female than male, indicating worse mental health among female workers. These impacts can also be seen with working longer daily hours: even in the case of a 4-10 work week, with 40 hours spread over 4 days, the longer days were shown to have higher fatigue for government employees impacted.
Similar gender differences were noted in other studies. In follow-up to the Whitehall study, a research team conducted a prospective cohort study following 2,960 middle-age full-time workers consisting of 2,248 men and 712 women. The results revealed a 267% increase in depression symptoms and a 284% increase in anxiety symptoms among those female workers working more than 55 hours per week, compared with those under standard working hours (35–40 hours per week). They also indicated a trend that for every 10-hour increase in weekly working hours, an associated 40% increase in depression symptoms and 31% increase in anxiety symptoms were noted. Similar trends were not noted among male workers. Similarly, Margot Shields surveyed 3,830 men and women between the ages of 25 and 54 who worked 35 hours or more per week between 1994 and 1997. She analyzed the relationship between working hours and depression. Her results found that women had increased likelihood of experiencing depression as more hours were worked.
Suicidal ideation is another concern for overtime work. Research conducted in South Korea recruited 67,471 samples, and the results revealed 30% higher suicidal ideation among workers having working hours more than 60 hours (31% increase in male workers and 33% increase in female workers). There was also increased suicidal ideation noted among workers working for 51–60 hours per week in both males and females.
In summary, mental effects related to overtime work include lower working satisfaction, depression, anxiety, and suicidal ideation. Among these, depression and anxiety are more predominant among female workers. Some research has proposed probable reasons for the gender difference. Female workers tend to take on more household responsibilities after work, which contributes to their mental stress. Also, female workers have been reported as relative minorities within the working place; at times experiencing lower job control, bullying, discrimination, etc.
Physical effects
Consecutive periods of working straight shifts, lack of breaks during the day, and consecutive days of working without a day off lead to decreased efficiency and productivity in workers. A synopsis of the book "Tired Cops: The Importance of Managing Police Fatigue" by Bryan Vila analyzed how these affected police officers in 2000. The abnormal work and sleep schedules were leading causes of the limited efficiency of police officers. This downturn in their effectiveness created unsafe environments for the communities around them.
Long-term effects were researched by The University of Texas Health Science Center at Houston. They studied the link between overtime and the increased risk of cardiovascular disorder (CVD) events. Their results included evidence that showed that for people who worked at least 10 years for each additional hour worked, starting from the 46th hour, his or her risk of a CVD event increased by 1%. In addition to these health risks, María Beniell, who received her Ph.D. in Economics from the Center for Monetary and Financial Studies (CEMFI), researched the correlation between working long hours and the likelihood of individuals smoking, drinking, having a high body mass index (BMI), and being less physically active. The long-term effects of alcohol consumption include increased on-the-job injuries and loss of productivity, family problems, risk of high blood pressure, stroke, other cardiovascular diseases, and more. The effects of smoking, in addition to similarities of the effects of alcohol, include increased risk of heart attacks, emphysema, and a large amount of cancers.
Margot Shields' 1994–1997 study also analyzed the relationship between long hours and changes in weight, smoking, drinking, and exercising. For men, longer hours were associated with unhealthy weight gain. Increased smoking occurred for both men and women, and an increase in drinking existed for women. No relationship could be drawn regarding changes in physical activity.
In Osaka, Japan, researchers completed a 5-year study on the effects of long work hours on hypertension in 1999. At the end of their study, they had surveyed 941 male Japanese white-collar workers. They concluded that long work hours are negatively-associated with the risk for hypertension.
Authors of one paper performed a mental analysis on four published cohort studies and nineteen unpublished studies looking at the effect of "long working hours" (defined by the authors as 55 or more hours per week) to look for an association of developing Type II Diabetes compared to a referent group of workers only working 35–40 hours per week. They found that there was statistically significant evidence for an association between longer working hours and development of Type II Diabetes, but only for individuals of low socioeconomic status such as manual laborers, when compared to other SES groups. The lower SES group working longer hours had a 29% increased risk of developing Type II diabetes; even after adjusting for physical activity, smoking, alcohol use, and obesity. However another author commented that residual confounding might account for this higher risk in the lower SES group compared to the higher SES group. They also postulated that sleep may be a mediator for this association, since inadequate sleep or sleep of poor quality / quantity can be a predictor of Type II diabetes. The workers in the lower SES group may have less control over their schedule, and this may include disruptive schedules interfering with circadian rhythm.
One large-scale study using data from the Individual-Participant-Data Meta-analysis in Working Population Consortium involving 85,494 workers from several European countries also looked at the effects of long work hours and the association with developing atrial fibrillation. These participants were free of atrial fibrillation at baseline. Mean age was 43.4 years. During follow up over 10 years, those working long hours (55 hours or more per week) were at 40% higher risk of developing atrial fibrillation compared to those working a standard 35-40 hour-week. In their study, the investigators controlled for age, sex, SES, smoking, BMI, physical activity, and alcohol consumption. The investigators also commented that this association between long working hours and atrial fibrillation appeared to be independent of classic risk factors of atrial fibrillation due to the similarities of the exposed group (long work hours) and the referent group.
For Coronary Heart Disease (CHD), a meta-analysis of four prospective studies published in 2012 found a 1.4-fold increased risk of CHD associated with long working hours. The investigators also noted that this association was higher for men than women. They hypothesized underlying mechanisms for this association may include longer exposure to stress, sleep deprivation, and / or dysregulation of the HPA axis causing an increase in cortisol production. They also noted that this estimate might have been biased for several reasons. One reason could have been if workers with underlying CHD reduced their working hours in the years before a CHD event. A second reason could be due to confounding of SES. A meta-analysis adjusting for these factors found the risk of a CHD event to be 1.13 instead. Furthermore, the study authors also found a 1.3-times higher risk for those working long hours.
Social effects
Work-life balance is a major aspect of employees' lives. Naturally, the more hours someone works, the less time they will have to spend with their family or other leisure activities. In 2007, professors from Penn State Abington analyzed the tradeoff between working overtime and home and family life activities. A major finding was that workers struggled to take time off for personal or family needs. However, the additional income from working long hours could limit the actual impact of this loss of time. More specifically, the impact of having a child exponentially increased the impact of working overtime. Especially at a young age, it is very important in child development for the parents to be involved to provide care and positive experiences. Due to this reason, work-life conflicts arise much more frequently for parents, as stress levels are heightened. These effects are even worse for single parents.
Mortality risk
"Karoshi" (translated as worked to death) is a concern in Japan. A paper published in 2006 showed that over a quarter of Japan's workforce were working 50 hours or more per week with half of them working 60 hours or more per week. The Ministry of Health, Labor, and Welfare launched an investigation in 2002 to examine 300 cases of possible Karoshi (death from being over-worked) during a time frame between 2002 and 2005. From their study, they recommended that employers offer a physician interview / guidance for any employee working over 100 hours overtime / month or if an employee requested a doctor's assessment.
Overall research evidence has shown that long working hours increases mortality risk. A UK census-based longitudinal study of 414,949 people aged 20–64 years, showed that overtime work increases mortality risk in men working for more than 55 hours per week. The authors showed that mortality is higher in technical, semi-routine, or routine occupations (positions with high demand, low levels of control, or perceived imbalance between effort and reward). The authors also demonstrated that increased mortality risk was mainly attributed to cardiovascular disease.
Similar results were found in other studies. A 30-year longitudinal study in Denmark of 5,249 employed Caucasian men aged 40–59 years showed that men working 41–45 hours per week had a 59% increased risk of mortality due to ischemic heart disease compared to men working less than 40 hours per week. The authors also found that physical fitness played a significant role, where among men with low physical fitness, those working more than 45 hours per week had more than twice the risk of death by ischemic heart disease compared to men working less than 40 hours per week; while this increased risk was not seen among the fittest men. Furthermore, a study based on data from the Swedish twin registry showed that there was an association between overtime work of more than 5 hours a week and increased mortality in women. This association was also seen in men, but only in the first five years of follow-up. In contrast, the authors showed that working less than five hours a week of overtime decreases the risk of mortality in men.
Counter arguments
Other studies argue that there is no direct cause-and-effect relationship between hours worked and short and long-term risks. Their claims include comments about factors that alter the outcome of effects. These include an individual's personality, occupation, and income. This research was done through a HILDA (Household, Income and Labour Dynamics in Australia) survey in 2001 and was completed in 2004. Prior research into these counter-arguments was completed by a group of researchers in 1997. They found links between increased CVD events and mental health disorders along with decreases in production as the number of hours worked increased. However, they state that further research is necessary before definitive conclusions can be made, as factors of each individual have vast consequences on the effect of working overtime. In addition, workers who work overtime when it is not mandatory find that there are very minimal effects on their fatigue levels.
In contrast, a Japanese study of 1,105 employees has demonstrated that longer working hours is associated with better health status in older employees. The authors of this study showed that overall health differed by age group, which reflects a generational difference with respect to their attitudes toward work. Among older workers, longer work hours might be beneficial as work-based social networks offer a structured environment, social support, and companionship.
Risk mitigation
While a definitive conclusion could not be made, suggestions exist to minimize the potential risks of long working hours. Creation of the work schedule should be managed properly to avoid multiple consecutive shifts, long periods of working without rest, and balanced breaks during the day. For families with children, it is very important that employees can manage their schedule for family or personal needs. This will help alleviate stress, provide flexible work hours throughout the year, and avoid many work-life conflicts.
In 1981, Jay Kim and Anthony Campagna, researchers from Ohio State University, studied the effects Flextime. Flextime allows workers to change their start and end work time. They first analyzed a wide range of studies done on flextime. Then they separated 353 employees into two groups: one that allowed flextime, and one that did not (control group). Their study found that flextime largely reduced unpaid absences for employees. They also found a general increase in worker performance. Flextime could impact coordinating schedules and meetings, as employee work schedules may vary.
See also
Critique of work
Eight-hour day
Flextime
Occupational burnout
Occupational stress
Overtime
Overwork
Retroactive overtime
Shift work
Working time
Work-life balance
References
Occupational safety and health
Over
Sleep disorders
Work–life balance | Effects of overtime | [
"Biology"
] | 3,322 | [
"Behavior",
"Sleep",
"Sleep disorders"
] |
71,575,013 | https://en.wikipedia.org/wiki/List%20of%20Trails%20media | Trails, known as in Japan, is a science fantasy series of role-playing video games by Nihon Falcom. Trails is a part of their larger The Legend of Heroes franchise and began with the release of Trails in the Sky in 2004. The games were released exclusively in Asia until the 2010s, with Xseed Games handling its English localization and global publishing until being replaced by NIS America in 2019. Trails games primarily feature turn-based combat, with some spin-offs and later entries featuring other styles of gameplay. The series is commonly praised for its character arcs and worldbuilding. It has also seen adapted and original manga, audio drama, and anime works, with the games selling 8.5 million copies by 2024.
Video games
Main series
Spin-offs
Audio
Literature
Other
Notes
References
Trails
Trails
Media
Multimedia works | List of Trails media | [
"Technology"
] | 168 | [
"Multimedia",
"Multimedia works"
] |
71,578,491 | https://en.wikipedia.org/wiki/Xanthoparmelia%20metastrigosa | Xanthoparmelia metastrigosa is a lichen which belongs to the Xanthoparmelia genus. It is found only in Australia. It is one of the few lichens that is listed as endangered.
Description
Grows to around 7–12 cm in diameter with irregular and dichotomously branched lobes. The upper surface of the lichen is yellow-green surface.
Habitat and range
Xanthoparmelia canobolasensis and Xanthoparmelia metastrigosa are known only from Mount Canobolas.
See also
List of Xanthoparmelia species
References
metastrigosa
Lichen species
Lichens of Australia
Lichens described in 1981
Taxa named by John Alan Elix | Xanthoparmelia metastrigosa | [
"Biology"
] | 153 | [
"Fungus stubs",
"Fungi"
] |
71,578,738 | https://en.wikipedia.org/wiki/PHY-Level%20Collision%20Avoidance | PHY-Level Collision Avoidance (PLCA) is a component of the Ethernet reconciliation sublayer (between the PHY and the MAC) defined within IEEE 802.3 clause 148. The purpose of PLCA is to avoid the shared medium collisions and associated retransmission overhead. PLCA is used in 802.3cg (10BASE-T1), which focuses on bringing Ethernet connectivity to short-haul embedded internet of things and low throughput, noise-tolerant, industrial deployment use cases.
In order for a multidrop 10BASE-T1S standard to successfully compete with CAN XL, some kind of arbitration was necessary. The linear arbitration scheme of PLCA somewhat resembles the one of the Byteflight, but PLCA was designed from scratch to accommodate the existing shared medium Ethernet MACs with their busy sensing mechanisms.
Operation
Under a PLCA scheme all nodes are assigned unique sequential numbers (IDs) in the range from 0 to N. Zero ID corresponds to a special "master" node that during the idle intervals transmits the synchronization beacon (a special heartbeat frame). After the beacon (within PLCA cycle) each node gets its transmission opportunity (TO). Each opportunity interval is very short (typically 20 bits), so overhead for the nodes that do not have anything to transmit is low. If the PLCA circuitry discovers that the node's TO cannot be used (the other node with a lower ID have started its transmission and the media is busy at the beginning of the TO for this node), it asserts the "local collision" input of the MAC thus delaying the transmission. The condition is cleared once the node gets its TO. A standard MAC reacts to the local collision with a backoff, however, since this is the first and only backoff for this frame, the backoff interval is equal to the smallest possible frame - and the backoff timer will definitely expire by the time the TO is granted, so there is no additional loss of performance.
See also
Internet of things (IOT)
References
Sources
Ethernet
Computer networking
Algorithms
Internet of things | PHY-Level Collision Avoidance | [
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71,581,030 | https://en.wikipedia.org/wiki/Xanthoparmelia%20californica | Xanthoparmelia californica is a lichen which belongs to the Xanthoparmelia genus. The lichen is uncommon and is listed as imperiled by the Nature Conservatory.
Description
Grows to around 3–6 cm in diameter with irregularly lobate lobes which are approximately 0.8-1.5 mm wide with smooth edges. The upper surface of the lichen is yellow-green to bluish green on the surface but becomes gains darker rings with age and light brown on the underside.
Habitat and range
Found in the North American southwest including the US states of California, Utah, and Arizona and the Mexican state of Sonora.
See also
List of Xanthoparmelia species
References
californica
Lichen species
Lichens of North America
Lichens described in 1984
Taxa named by Mason Hale | Xanthoparmelia californica | [
"Biology"
] | 169 | [
"Fungus stubs",
"Fungi"
] |
71,581,452 | https://en.wikipedia.org/wiki/Religious%20fasting | Fasting is practiced in various religions. Examples include Lent in Christianity and Yom Kippur, Tisha B'av, Fast of Esther, Fast of Gedalia, the Seventeenth of Tammuz, and the Tenth of Tevet in Judaism. Muslims fast during the month of Ramadan each year. The fast includes refraining from consuming any food or liquid from sunup until sundown.
Details of fasting practices differ. Eastern Orthodox Christians fast during specified fasting seasons of the year, which include not only the better-known Great Lent, but also fasts on every Wednesday and Friday (except on special holidays), together with extended fasting periods before Christmas (the Nativity Fast), after Easter (the Apostles Fast) and in early August (the Dormition Fast).
Members of The Church of Jesus Christ of Latter-day Saints (Mormons) fast for a full 24-hour period once per month – usually before the main meal on the first Saturday of the month and ending with the main meal on the following Sunday – this is termed by the church as fast and testimony weekend. Many church members use this time to pray and meditate to increase their spiritual strength. Many also use this time to bear testimony of the church at a special church service held on the first Sunday of each month. They also give [at least] the money they saved by their fast to the church which uses it for support of the poor. In addition, Latter-Day Saints may also fast and pray voluntarily for a full 24 or 48 hours when they feel that they need extra spiritual strength or guidance. Like Muslims, they refrain from all drinking and eating unless they are small children or are physically unable to fast for example, diabetics are not expected to fast.
Fasting is also a feature of religions such as Hinduism, Buddhism and Jainism. Mahayana traditions that follow the Brahma's Net Sutra may recommend that the laity fast "during the six days of fasting each month and the three months of fasting each year". Members of the Baháʼí Faith observe a Nineteen-Day Fast from sunrise to sunset during March each year.
Baháʼí Faith
In the Baháʼí Faith, fasting is observed from sunrise to sunset during the Baháʼí month of ʻAlaʼ ( 1 or 2 March – 19 or 20 March). Baháʼu'lláh established the guidelines in the Kitáb-i-Aqdas. It is the complete abstaining from both food and drink during daylight hours (including abstaining from smoking). Consumption of prescribed medications is not restricted. Observing the fast is an individual obligation and is binding on Baháʼís between 15 years (considered the age of maturity) and 70 years old.
Exceptions to fasting include individuals younger than 15 or older than 70; those suffering illness; women who are pregnant, nursing, or menstruating; travellers who meet specific criteria; individuals whose profession involves heavy labor and those who are very sick, where fasting would be considered dangerous. For those involved in heavy labor, they are advised to eat in private and generally to have simpler or smaller meals than are normal.
Along with obligatory prayer, it is one of the greatest obligations of a Baháʼí. In the first half of the 20th century, Shoghi Effendi, explains: "It is essentially a period of meditation and prayer, of spiritual recuperation, during which the believer must strive to make the necessary readjustments in his inner life, and to refresh and reinvigorate the spiritual forces latent in his soul. Its significance and purpose are, therefore, fundamentally spiritual in character. Fasting is symbolic, and a reminder of abstinence from selfish and carnal desires."
Buddhism
Buddhist monks and nuns following the Vinaya rules commonly do not eat each day after the noon meal. This is not considered a fast but rather a disciplined regimen aiding in meditation and good health.
Fasting is practiced by lay Buddhists during times of intensive meditation, such as during a retreat. During periods of fasting, followers completely stay away from eating animal products, although they do allow consumption of milk. Furthermore, they also avoid eating processed foods and the five pungent foods which are: garlic (Allium sativum), Welsh onion (Allium fistulosum), wild garlic (Allium oleraceum), garlic chives (Allium tuberosum), and asafoetida ("asant", Ferula asafoetida).
The Middle Path refers to avoiding extremes of indulgence on the one hand and self-mortification on the other. Prior to attaining Buddhahood, prince Siddhartha practiced a short regime of strict austerity and following years of serenity meditation under two teachers which he consumed very little food. These austerities, undertaken alongside five other ascetics did not lead to progress in meditation, liberation (moksha), or the ultimate goal of nirvana. Henceforth, prince Siddhartha practiced moderation in eating which he later advocated for his disciples.
On Uposatha days, roughly once a week, lay Buddhists are instructed to observe the eight precepts which includes refraining from eating after noon until the following morning. The eight precepts closely resemble the ten vinaya precepts for novice monks and nuns. The novice precepts are the same with an added prohibition against handling money.
The Vajrayana practice of Nyung Ne is based on the tantric practice of Chenrezig. It is said that Chenrezig appeared to an Indian nun who had contracted leprosy and was on the verge of death. Chenrezig taught her the method of Nyung Ne in which one keeps the eight precepts on the first day, then refrains from both food and water on the second. Although seemingly against the Middle Way, this practice is to experience the negative karma of both oneself and all other sentient beings and, as such is seen to be of benefit. Other self-inflicted harm is discouraged.
Christianity
Fasting is a practice in several Christian denominations and is done both collectively during certain seasons of the liturgical calendar, or individually as a believer feels led by the Holy Spirit. In the traditional Black Fast, the observant abstains from food and liquids for a whole day until the evening, and at sunset, traditionally breaks the fast with a vegetarian meal. Christians normatively fasted in this way during Lent prior to the 6th century, though it continues in certain denominations such as the Coptic Orthodox Church.
The Teaching of the Twelve Apostles, written in the first century A.D., directed Christians to fast on both Wednesdays, in remembrance of the betrayal of Christ by Judas on Spy Wednesday, and Fridays, in mourning of the crucifixion of Jesus on Good Friday. Historically, the Orthodox, Catholic, Anglican and Methodist denominations of Christianity have emphasized the importance of the Friday fast, which has traditionally involved fasting and abstinence from meat, lacticinia and alcohol.
The pattern of fasting and praying for forty days is seen in the Bible, on which basis the liturgical season of Lent was established. In the Torah, Moses went into the mountains for forty days and forty nights to pray and fast "without eating bread or drinking water" before receiving the Ten Commandments (cf. ). Likewise, the prophet Elijah went into the mountains for forty days and nights to fast and pray "until he reached Horeb, the mountain of God" when "the word of the Lord came to him" (cf. ). The early Christian bishop Maximus of Turin wrote that as Elijah by "fasting continuously for a period of forty days and forty nights...merited to extinguish the prolonged and severe dryness of the whole world, doing so with a stream of rain and steeping the earth's dryness with the bounty of water from heaven", in the Christian tradition, this is interpreted as being "a figure of ourselves so that we, also fasting a total of forty days, might merit the spiritual rain of baptism...[and] a shower from heaven might pour down upon the dry earth of the whole world, and the abundant waters of the saving bath might saturate the lengthy drought of the Gentiles." In the New Testament, Jesus went into the desert to fast and pray for forty days and forty nights; it was during this time that Satan tried to tempt him (cf. ). The forty day and night fasts of Moses, Elijah, and Jesus prepared them for their work, and their examples were foundational to the establishment of Lent.
In Western Christianity, fasting is observed during the forty-day season of Lent by many communicants of the Catholic Church, Lutheran Churches, Anglican Communion, Moravian Church, Methodist Churches, Western Orthodox Churches, United Protestant Churches and certain Reformed Churches, to commemorate the fast observed by Christ during his temptation in the desert. While some Western Christians fast during the entire season of Lent, Ash Wednesday and Good Friday are nowadays emphasized by Western Christian denominations as the normative days of fasting within the Lenten season. In many Western Christian Churches, including those of the Catholic, Methodist and Baptist traditions, certain congregations have committed to undertaking the Daniel Fast during the whole season of Lent, in which believers practice abstinence from meat, lacticinia and alcohol for the entire forty days of the liturgical season. In certain denominations, such as the Coptic Orthodox Church, as well as in certain countries, such as India and Pakistan, many Christians observe the Black Fast throughout the whole season of Lent. After attending a worship service, often on Wednesday evenings, it is common for Christians of various denominations to break that day's Lenten fast together through a communal Lenten supper, which is held in the church's parish hall. Along with fasting, certain Christian denominations such as the Coptic Orthodox Church, enjoin sexual abstinence during Lent for believers "to give themselves time for fasting and prayer ()."
Many Christians fast before receiving Holy Communion (traditionally this has been from midnight until the reception of the Eucharist). This is known as the Eucharistic Fast.
Catholicism
For Catholics, fasting, taken as a technical term, is the reduction of one's intake of food to one full meal (which may not contain meat on Ash Wednesday, Good Friday, and Fridays throughout the entire year unless a solemnity should fall on Friday) and two small meals (known liturgically as collations), both of which together should not equal the large meal. Eating solid food between meals is not permitted. Fasting is required of the faithful between the ages of 18 and 59 on specified days. Complete abstinence of meat for the day is required of those 14 and older. Meat is understood as that of warm-blooded land animals.
In the Catholic Church, the forty days of Lent were days of fasting and abstinence from meat and lacticinia until these rules were relaxed by Pope Benedict XIV in Non Ambigimus and by Pope Leo XIII in Indultum quadragesimale. Prior to the closure of the Second Vatican Council in 1965, all of the weekdays of Lent, totaling forty days, were days of fasting in the Catholic Church, with Fridays and Saturdays being days of abstinence from meat; these rules continue to be observed by certain Traditional Catholics, such as those worshipping in the chapels of Congregation of Mary Immaculate Queen (CMRI). Pope Pius XII initially relaxed some of the regulations concerning fasting in 1956. In 1966, Pope Paul VI in his apostolic constitution Paenitemini, changed the strictly regulated Catholic fasting requirements. He recommended that fasting be appropriate to the local economic situation, and that all Catholics voluntarily fast and abstain. In the United States, there are only two obligatory days of fast – Ash Wednesday and Good Friday. Though not under the pain of mortal sin, fasting on all forty days of Lent is "strongly recommended". The Fridays of Lent are days of abstinence. Pastoral teachings since 1966 have urged voluntary fasting during Lent and voluntary abstinence on the other Fridays of the year. The regulations concerning such activities do not apply when the ability to work or the health of a person would be negatively affected.
Anglicanism
The 1662 Book of Common Prayer prescribes certain days as days for fasting and abstinence, "consisting of the 40 days of Lent, the ember days, the three Rogation days (the Monday to Wednesday following the Sunday after Ascension Day), and all Fridays in the year (except Christmas, if it falls on a Friday)":
A Table of the Vigils, Fasts, and Days of Abstinence, to be Observed in the Year.
The eves (vigils) before:
The Nativity of our Lord.
The Purification of the Blessed Virgin Mary.
The Annunciation of the Blessed Virgin.
Easter Day.
Ascension Day.
Pentecost.
St. Matthias.
St. John Baptist.
St. Peter.
St. James.
St. Bartholomew.
St. Matthew.
St. Simon and St. Jude.
St. Andrew.
St. Thomas.
All Saints' Day.
Note: if any of these Feast-Days fall upon a Monday, then the Vigil or Fast-Day shall be kept upon the Saturday, and not upon the Sunday next before it.
Days of Fasting, or Abstinence.
I. The Forty Days of Lent.
II. The Ember Days at the Four Seasons, being the Wednesday, Friday, and Saturday after the First Sunday in Lent, the Feast of Pentecost, September 14, and December 13.
III. The Three Rogation Days, being the Monday, Tuesday, and Wednesday, before Holy Thursday, or the Ascension of our Lord.
IV. All the Fridays in the Year, except Christmas Day.
Saint Augustine's Prayer Book defines "Fasting, usually meaning not more than a light breakfast, one full meal, and one half meal, on the forty days of Lent." Abstinence, according to Saint Augustine's Prayer Book, "means to refrain from some particular type of food or drink. One traditional expression of abstinence is to avoid meat on Fridays in Lent or through the entire year, except in the seasons of Christmas and Easter. It is common to undertake some particular act of abstinence during the entire season of Lent. This self-discipline may be helpful at other times, as an act of solidarity with those who are in need or as a bodily expression of prayer."
In the process of revising the Book of Common Prayer in various provinces of the Anglican Communion the specification of abstinence or fast for certain days has been retained. Generally Lent and Fridays are set aside, though Fridays during Christmastide and Eastertide are sometimes avoided. Often the Ember days or Rogation days are also specified, and the eves (vigils) of certain feasts.
In addition to these days of fasting, many Anglicans also observe a eucharistic fast. Saint Augustine's Prayer Book states that the eucharistic fast is a "strict fast from both food and drink from midnight" that is done "in order to receive the Blessed Sacrament as the first food of the day" in "homage to our Lord". It implores Anglicans to fast for some hours before the Midnight Mass of Christmas Eve, the first liturgy of Christmastide.
From the execution of Charles I, the Supreme Governor of the Church of England, on 30 January 1649, until it was repealed in the Anniversary Days Observance Act 1859, the church included January 30 as a fast day to commemorate his becoming King Charles the Martyr. The Society of King Charles the Martyr, an Anglican Catholicism group, continues to observe January 30 as the feast day of Charles.
Eastern and Oriental Orthodoxy
Orthodox Christians are required to fast on Wednesdays (in memory of Jesus' betrayal on Spy Wednesday) and Fridays (in memory of Jesus' crucifixion on Good Friday), which means not consuming olive oil, meat, fish, milk and dairy products until evening (sundown). The original Orthodox Christian law forbids all products derived from creatures who have blood. The supper that is eaten after the fast is broken in the evening must not include shellfish. Additionally, Orthodox Christians abstain from sexual relations on Wednesdays and Fridays throughout the year, as with the entirety of Lent, the Nativity Fast and the fifteen days before the Feast of the Assumption of Mary.
In the Coptic Orthodox Church, the Black Fast is the normative way of fasting during Great Lent; Coptic Orthodox Christians go without water and food from midnight to sunset; after that time, the consumption of water and one vegetarian meal is permitted. Married couples abstain from sexual relations during this period "to give themselves time for fasting and prayer (1 Cor. 7: 5)."
For Eastern Orthodox Christians, fasting is an important spiritual discipline, found in both the Old Testament and the New, and is tied to the principle in Orthodox theology of the synergy between the body (Greek: soma) and the soul (pneuma). That is to say, Orthodox Christians do not see a dichotomy between the body and the soul but rather consider them as a united whole, and they believe that what happens to one affects the other (this is known as the psychosomatic union between the body and the soul). Saint Gregory Palamas argued that man's body is not an enemy but a partner and collaborator with the soul. Christ, by taking a human body at the Incarnation, has made the flesh an inexhaustible source of sanctification. This same concept is also found in the much earlier homilies of Saint Macarius the Great.
Fasting can take up a significant portion of the calendar year. The purpose of fasting is not to suffer, but according to Sacred Tradition to guard against gluttony and impure thoughts, deeds and words. Fasting must always be accompanied by increased prayer and almsgiving (donating to a local charity, or directly to the poor, depending on circumstances). To engage in fasting without them is considered useless or even spiritually harmful. To repent of one's sins and to reach out in love to others is part and parcel of true fasting.
Partial fasting within the Ethiopian Orthodox Church, abstaining from meat and milk, takes place during certain times of the year and lasts for weeks.
Fast days
There are five fasting seasons, which include:
Great Lent (40 days) and Holy Week (seven days)
Nativity Fast (40 days)
Apostles' Fast (variable length)
Dormition Fast (two weeks)
Fast of Nineveh (three days) called Saint Sargis the General's fast in the Armenian Apostolic Church
Wednesdays and Fridays are also fast days throughout the year (with the exception of fast-free periods). In some Orthodox monasteries, Mondays are also observed as fast days (Mondays are dedicated to the angels, and monasticism is called the "angelic life").
Other days occur which are always observed as fast days:
The paramony or Eve of Christmas and of Theophany (Epiphany)
Beheading of John the Baptist
Exaltation of the Cross
Rules
Fasting during these times includes abstention from:
meat, fish, eggs and milk products
sometimes oil (interpreted variously as abstention from olive oil only, or as abstention from all cooking oils in general), and
red wine (which is often interpreted as including all wine or alcoholic beverages)
sexual activity (where fasting is pre-communion)
When a feast day occurs on a fast day, the fast is often mitigated (lessened) to some degree (though meat and dairy are never consumed on any fast day). For example, the Feast of the Annunciation almost always occurs within the Great Lent in the Orthodox calendar: in this case fish (traditionally haddock fried in olive oil) is the main meal of the day.
There are two degrees of mitigation: allowance of wine and oil; and allowance of fish, wine and oil. The very young and very old, nursing mothers, the infirm, as well as those for whom fasting could endanger their health somehow, are exempt from the strictest fasting rules.
On weekdays of the first week of Great Lent, fasting is particularly severe, and many observe it by abstaining from all food for some period of time. According to strict observance, on the first five days (Monday through Friday) there are only two meals eaten, one on Wednesday and the other on Friday, both after the Presanctified Liturgy. Those who are unable to follow the strict observance may eat on Tuesday and Thursday (but not, if possible, on Monday) in the evening after Vespers, when they may take bread and water, or perhaps tea or fruit juice, but not a cooked meal. The same strict abstention is observed during Holy Week, except that a vegan meal with wine and oil is allowed on Great Thursday.
On Wednesday and Friday of the first week of Great Lent the meals which are taken consist of xerophagy (literally, "dry eating") i.e. boiled or raw vegetables, fruit, and nuts. In a number of monasteries, and in the homes of more devout laypeople, xerophagy is observed on every weekday (Monday through Friday) of Great Lent, except when wine and oil are allowed.
Those desiring to receive Holy Communion keep a total fast from all food and drink from midnight the night before (see Eucharistic discipline).
Fast-free days
During certain festal times the rules of fasting are done away with entirely, and everyone in the church is encouraged to feast with due moderation, even on Wednesday and Friday. Fast-free days are as follows:
Bright Week – the period from Pascha (Easter Sunday) through Thomas Sunday (the Sunday after Pascha), inclusive.
The Afterfeast of Pentecost – the period from Pentecost Sunday until the Sunday of All Saints, inclusive.
The period from the Nativity of the Lord until (but not including) the eve of the Theophany (Epiphany).
The day of Theophany.
Two of the last three weeks before the beginning of Great Lent:
During the antepenultimate (third-to-last) week before Great Lent, all foods all allowed, even on Wednesday and Friday (popularly called "fast-free week", "meat-fare week" or "omnivorous week").
During the penultimate (second-to-last) week before Great Lent, regular fasting resumes on Wednesday and Friday (sometimes called "checkered week").
On the final week, believers cease eating meat but eat large quantities of eggs and dairy products to use them up before the beginning of Great Lent (popularly called "butter week" or "cheese-fare week").
Methodism
In Methodism, fasting is considered one of the Works of Piety. "The General Rules of the Methodist Church," written by the founder of Methodism, John Wesley, wrote that "It is expected of all who desire to continue in these societies that they should continue to evidence their desire of salvation, by attending upon all the ordinances of God, such are: the public worship of God; the ministry of the Word, either read or expounded; the Supper of the Lord; family and private prayer; searching the Scriptures; and fasting or abstinence." Methodism's principal liturgical book The Sunday Service of the Methodists (put together by John Wesley), as well as The Directions Given to Band Societies (25 December 1744), mandated for Methodists fasting and abstinence from meat on all Fridays of the year, a practice that was reemphasized by Phoebe Palmer and became standard in the Methodist churches of the holiness movement. Additionally, the Discipline of the Wesleyan Methodist Church required Methodists to fast on "the first Friday after New-Year's-day; after Lady-day; after Midsummer-day; and after Michaelmas-day." Historically, Methodist clergy are required to fast on Wednesdays, in remembrance of the betrayal of Christ, and on Fridays, in remembrance of His crucifixion and death. Wesley himself also kept the Eucharistic Fast, fasting before receiving Holy Communion "for the purpose of focusing his attention on God," and asked other Methodist Christians to do the same. In accordance with Scripture and the teachings of the Church Fathers, fasting in Methodism is done "from morning until evening"; John Wesley kept a more rigorous Friday Fast, fasting from sundown (on Thursday) until sundown (on Friday) in accordance with the liturgical definition of a day.
In many Methodist connexions, fasting during the Christian season of repentance, Lent, has been emphasized due to what is seen as its biblical origin of "Jesus, as part of his spiritual preparation, went into the wilderness and fasted 40 days and 40 nights". Urged by the hierarchs of certain Methodist connexions to do so, many Methodist congregations undertake the Daniel Fast for the whole duration of Lent, in which believers abstain from meat and lacticinia for the entire 40 day season of repentance. Good Friday, which is towards the very end of the Lenten season, is traditionally an important day of communal fasting for Methodists. Rev. Jacqui King, the minister of Nu Faith Community United Methodist Church in Houston, explained the philosophy of fasting during Lent as "I'm not skipping a meal because in place of that meal I'm actually dining with God".
Oriental Orthodox
All Oriental Orthodox churches practice fasting; however, the rules of each church differ. All churches require fasting from midnight onwards before one receives Holy Communion. All churches practice fasting on most Wednesdays and Fridays throughout the year as well as observing many other days. Monks and nuns also observe additional fast days not required of the laity.
The Armenian Apostolic Church (with the exception of the Armenian Patriarchate of Jerusalem) has followed the Gregorian calendar since 1923, making it and the Finnish Orthodox Church (an Eastern Orthodox church) the only Orthodox churches to primarily celebrate Easter on the same date as Western Christianity. As a result, the Armenian church's observation of Lent generally begins and ends before that of other Orthodox churches.
Lutheran
Martin Luther, the Protestant Reformer, held that fasting served to "kill and subdue the pride and lust of the flesh". As such, the Lutheran churches often emphasize voluntary fasting over collective fasting, though certain liturgical seasons and holy days are times for communal fasting and abstinence. Certain Lutheran communities advocate fasting during designated times such as Lent, especially on Ash Wednesday and Good Friday. A Handbook for the Discipline of Lent delineates the following Lutheran fasting guidelines:
It is also considered to be an appropriate physical preparation for partaking of the Eucharist, but fasting is not necessary for receiving the sacrament. Martin Luther wrote in his Small Catechism "Fasting and bodily preparation are certainly fine outward training, but a person who has faith in these words, 'given for you' and 'shed for you for the forgiveness of sin' is really worthy and well prepared."
Reformed
John Calvin, the figurehead of the Reformed tradition (the Continental Reformed, Congregational, Presbyterian, and Anglican Churches) held that communal fasts "would help assuage the wrath of God, thus combating the ravages of plague, famine and war." In addition, individual fasting was beneficial in that "in preparing the individual privately for prayer, as well as promoting humility, the confession of guilt, gratitude for God's grace and, of course, discipling lust." As such, many of the churches in the Reformed tradition retained the Lenten fast in its entirety. The Reformed Church in America describes the first day of Lent, Ash Wednesday, as a day "focused on prayer, fasting, and repentance" and considers fasting a focus of the whole Lenten season, as demonstrated in the "Invitation to Observe a Lenten Discipline", found in the Reformed liturgy for the Ash Wednesday service, which is read by the presider:
Good Friday, which is towards the end of the Lenten season, is traditionally an important day of communal fasting for adherents of the Reformed faith. In addition, within the Puritan/Congregational tradition of Reformed Christianity, special days of humiliation and thanksgiving "in response to dire agricultural and meteororological conditions, ecclesiastsical, military, political, and social crises" are set apart for communal fasting.
In more recent years, many churches affected by liturgical renewal movements have begun to encourage fasting as part of Lent and sometimes Advent, two penitential seasons of the liturgical year.
Anabaptist
Members of the Anabaptist movement generally fast in private. The practice is not regulated by ecclesiastic authority.
Moravian / Hussite
Members of the Moravian Church voluntarily fast during the season of Lent, along with making a Lenten sacrifice for the season as a form of penitence.
Pentecostalism
Classical Pentecostalism does not have set days of abstinence, but individuals in the movement may feel they are being directed by the Holy Spirit to undertake either short or extended fasts. Although Pentecostalism has not classified different types of fasting, certain writers within the movement have done so. Arthur Wallis writes about the "Normal Fast" in which pure water alone is consumed. The Black Fast in which nothing, not even water, is consumed is also mentioned. In addition to the normal fast and black fast, some undertake what is referred to as the Daniel Fast (or Partial Fast) in which only one type of food (e.g., fruit or fruit and non-starchy vegetables) is consumed. In the Daniel Fast, outlined in Daniel 10:2-3 in the Bible, "In those days I Daniel was mourning three full weeks. I ate no pleasant bread, neither came flesh nor wine in my mouth, neither did I anoint myself at all until three whole weeks were fulfilled." In some circles of Pentecostals, the term "fast" is simply used, and the decision whether to drink water as a part of the fast is determined on an individual basis.
The Church of Jesus Christ of Latter-day Saints
For members of the Church of Jesus Christ of Latter-day Saints (LDS Church), fasting is total abstinence from food and drink accompanied by prayer. Members are encouraged to fast on the first Sunday of each month, designated as Fast Sunday. During Fast Sunday, members abstain from food and drink for two consecutive meals in a 24-hour period; this is usually Sunday breakfast and lunch, thus the fasting occurs between the evening meal on Saturday and the evening meal on Sunday. The money saved by not having to purchase and prepare meals is donated to the church as a fast offering, which is then used to help people in need. Members are encouraged to donate more than just the minimal amount, and be as generous as possible. Gordon B. Hinckley stated: "Think ... of what would happen if the principles of fast day and the fast offering were observed throughout the world. The hungry would be fed, the naked clothed, the homeless sheltered. ... A new measure of concern and unselfishness would grow in the hearts of people everywhere." Fasting and the associated donations for use in assisting those in need, are an important principle as evidenced by church leaders addresses on the subject during general conferences of the church.
Sunday worship meetings on Fast Sunday include opportunities for church members to publicly bear testimony of their belief in Jesus Christ and church doctrine during the sacrament meeting portion, often referred to as fast and testimony meeting.
Fasting is also encouraged for members any time they desire to grow closer to God and to exercise self-mastery of spirit over body. Members may also implement personal, family, or group fasts any time they desire to solicit special blessings from God, including health or comfort for themselves or others.
Daniel Fast
The Book of Daniel (1:2–20, and 10:2–3) refers to a 10- or 21-day avoidance (the Daniel Fast) of foods declared unclean by God in the laws of Moses. In modern versions of the Daniel Fast, food choices may be limited to whole grains, fruits, vegetables, pulses, nuts, seeds and oil. The Daniel Fast resembles the vegan diet in that it excludes foods of animal origin. The passages strongly suggest that the Daniel Fast will promote good health and mental performance, due to God's blessing.
Hinduism
Fasting is an optional part of Hinduism. Individuals observe different kinds of fasts based on personal beliefs and local customs.
Fasting days
Some Hindus fast on certain days of the month such as Ekadasi, Pradosha, or Purnima. Certain days of the week are also set aside for fasting depending on personal belief and favorite deity. For example, devotees of Shiva tend to fast on Mondays, while devotees of Vishnu tend to fast on Thursdays and devotees of Ayyappa tend to fast on Saturdays. Tuesday fasting is common in southern India as well as northwestern India. In Tamil Nadu, it is believed that Tuesday is dedicated to Goddess Mariamman, a form of Goddess Shakti. Devotees eat before sunrise and drink only liquids between sunrise and sunset. Only liquids between a prescribed period, like water fasting, is half fasting.
In the North, Tuesday and Saturday are dedicated to Lord Hanuman and devotees are allowed only to consume milk and fruit between sunrise and sunset. Thursday fasting is common among the Hindus of northern India. On Thursdays, devotees listen to a story before opening their fast. On the Thursday fasters also worship Vrihaspati Mahadeva. They wear yellow clothes, and meals with yellow colour are preferred. Women worship the banana tree and water it. Food items are made with yellow-coloured ghee. Thursday is also dedicated to Guru and many Hindus who follow a guru will fast on this day.
Fasting during religious festivals is also very common. Common examples are Maha Shivaratri (Most people conduct a strict fast on Maha Shivratri, not even consuming a drop of water ), or the nine days of Navratri (which occurs twice a year in the months of April and October/November during Vijayadashami just before Diwali, as per the Hindu calendar). Karwa Chauth is a form of fasting practised in some parts of India where married women undertake a fast for the well-being, prosperity, and longevity of their husbands. The fast is broken after the wife views the moon through a sieve.
In the fifth month (Shravan Maas) of the Hindu calendar, many celebrate Shraavana. During this time some will fast on the day of the week that is reserved for worship of their chosen god(s), while others will fast during the entire month. In the state of Andhra Pradesh, the month of Kartik (month), which begins with the day after Deepavali is often a period of frequent (though not necessarily continuous) fasting for some people, especially women. Common occasions for fasting during this month include Mondays for Lord Shiva, the full-moon day of Karthika and the occasion of Naagula Chaviti.
Methods of fasting
Methods of fasting also vary widely and cover a broad spectrum. If followed strictly, the person fasting does not partake any food or water from the previous day's sunset until 48 minutes after the following day's sunrise. Fasting can also mean limiting oneself to one meal during the day, abstaining from eating certain food types or eating only certain food types. In any case, the fasting person is not supposed to eat or even touch any animal products (i.e., meat, eggs) except dairy products. For many Hindu communities during fasting, starchy items such as potatoes, Sago and sweet potatoes, purple-red sweet potatoes, amaranth seeds, nuts and shama millet are allowed. Popular fasting dishes in western part of India include Farari chevdo, Sabudana Khichadi or peanut soup.
Fasting in scriptures
In Shri Vidya, one is forbidden to fast because the Devi is within them, and starving would in return starve the god. The only exception in Srividya for fasting is on the anniversary of the day one's parents died.
Mahabharata: Anushasana Parva (Book 13)
Yudhishthira asks Bhishma, "what constitutes the highest penances?" Bheeshma states (in section 103):....there is no penance that is superior to abstention from food! In this connection is recited the ancient narrative of the discourse between Bhagiratha and the illustrious Brahman (the Grandsire of the Creation).Bhagiratha says, The vow of fast was known to Indra. He kept it a secret but USANAS first made it known to the universe ... In my opinion, there is no penance higher than fast... the present that flowed from me were as copious as the stream of the Ganga herself (but ..) it is not through the merits of these acts that I have attained this region.Bhagiratha did many sacrifices and gave gifts.and saysBhagiratha observed the vow of fasting and reached "the region of Brahman". Bheeshma advises Yudhishthira,Do thou practice this vow (of fasting) of very superior merit that is not known to all.In section 109, of the same book, Yudhishthira asks Bheesma, What is the highest, most beneficial and fruitful of all kinds of fasts in the world? Bheeshma says "fasting on the 12th day of the lunar month and worship Krishna, for the whole year. Krishna is worshipped in twelve forms as Kesava, Narayana, Madhava, Govinda, Vishnu, the slayer of Madhu, who covered the universe in three steps, the dwarf (who beguiled Mahabali), Sridhara, Hrishikesha, Padmanabha, Damodara, Pundhariksha. and Upendra. After fasting, one must feed a number of Brahmans." Bheeshma says " the illustrious Vishnu, that ancient being, has himself said that there is no fast that possesses merit superior to what attach to fast of this kind."
In section 106, of the same book, Yudhishthira says,The disposition (of observing fasts) is seen in all orders of men including the very Mlechchhas..... What is the fruit that is earned in this world by the man that observes fasts? Bheeshma replies that he had asked Angiras the very same question that he had asked him that day. The illustrious Angiras says,Brahmans and kshatriya should fast for three nights at a stretch is the maximum. A person who fasts on the eight and fourteenth day of the dark fortnight becomes freed from maladies of all kinds and possessed of great energy.Fasting for one meal every day during a lunar month gets various boons according to the month in which he fasts. For example, fasting for one meal every day during Margashirsha, 'acquires great wealth and corn'.
Vaishnavism
In Vaishnavism, in some specific periods of time (like Caturmasya or Ekadashi fasting) it is said that one who fasts on these days and properly doing spiritual practice on these days like associating with devotees -sangha, chanting holy names of Hari (Vishnu, Narayana, Rama, Krishna) and similar (shravanam, kirtanam vishno) may be delivered from sins.
Islam
In Islam, fasting requires abstinence from food, drink, drugs (including nicotine) and sexual intercourse. However, there is also a broader sense of fasting which includes abstaining from any falsehood in speech and action, abstaining from any ignorant and indecent speech, and from arguing and fighting. Therefore, fasting strengthens control of impulses and helps develop good behavior. During the sacred month of Ramadan, believers strive to purify body and soul and increase their taqwa (good deeds and God-consciousness). This purification of body and soul harmonizes the inner and outer spheres of an individual.
Muslims aim to improve their body by reducing food intake and maintaining a healthier lifestyle. Overindulgence in food is discouraged and eating only enough to silence the pain of hunger is encouraged. Muslims believe they should be active, tending to all their commitments and never falling short of any duty. On a moral level, believers strive to attain the most virtuous characteristics and apply them to their daily situations. They try to show compassion, generosity and mercy to others, exercise patience, and control their anger. In essence, Muslims are trying to improve what they believe to be good moral character and habits.
Ramadan
Fasting is obligatory for every Muslim one month in the year, during Ramadan. Each day, the fast begins at dawn and ends at sunset. During this time Muslims are asked to remember those who are less fortunate than themselves as well as bringing them closer to God. Non obligatory fasts are two days a week as well as the middle of the month, as recommended by Muhammad.
Although fasting at Ramadan is fard (obligatory), exceptions are made for persons in particular circumstances. Muslims are encouraged to fast optionally outside of Ramadan as well, as a way of asking forgiveness from or showing gratitude to God and in many other days.
Ashura
Ashura is the Islamic counterpart to the Jewish fast of Yom Kippur, to thank God for saving Moses and the Jewish people from Egypt. It is also encouraged to fast the day before, or the day after, or all three days. The same day also marks the martyrdom of Husayn ibn Ali and his family. Although, it is not obligatory, many Sunni Muslims fast on this day. Shia Muslims usually refrain from eating on that day till the time of Asr Prayer and called it a "Faqa", which means abstaining from consuming food without an intent of a fast, in remembrance of the sacrifice of Husayn ibn Ali and his associates.
Shawwal
Some Muslims observe fasting during any six days of Shawwal. The reasoning behind this tradition is that a good deed in Islam is rewarded 10 times, hence fasting 30 days during Ramadan and 6 days during Shawwāl is equivalent to fasting the whole year in fulfillment of the obligation.
Arafah
Fasting on the day of Arafah for non-pilgrims is a highly recommended Sunnah which entails a great reward; Allah forgives the sins of two years. Imam An-Nawawi mentioned in his book al-Majmu’, “With regard to the ruling on this matter, Imam As-Shafi’i and his companions said: It is mustahabb (recommended) to fast on the day of Arafah for the one who is not in Arafah. Those who are not performing their hajj may observe fasting to gain the merits of the blessed day.
Dhu al-Hijjah
During the first nine days of the month of Dhu al-Hijjah, i.e. the nine days before Eid al-Adha, and from these especially on Day of Arafah and day before Eid al-Adha.
Ayyam al-Bid
Ayyam al-Bīḍ or "The White Days", the three days of the full moon. These fall on the 13th, 14th, and 15th of each Islamic month. Fasting in this style results in 32 optional fasts in a lunar year, as fasting in Ramadan is mandatory and it is forbidden to fast on the 13th of Dhu al-Hijjah.
Fast of Dawud
Fast of Dawud (David): fasting alternate days the whole year round. This style of fasting is attributed to Dawud. The discouragement of fasting on Friday alone without also fasting on either Thursday or Saturday is lifted for those fasting consistently in this style. It results in around 140 optional fasts in a lunar year, which is around 355 days long.
Forbidden days
Islam forbids fasting on certain days.
Jainism
Prior to undertaking a Jain fast, a person must make a vow, or a formal statement of intent.
Judaism
Fasting for Jews means completely abstaining from food and drink, including water. Traditionally observant Jews fast six days of the year. With the exception of Yom Kippur, fasting is never permitted on Shabbat, for the commandment of keeping Shabbat is biblically ordained and overrides the later rabbinically instituted fast days. (The minor fast of the Tenth of Tevet could also override the Shabbat, but the current calendar system prevents this from ever occurring.)
Yom Kippur is considered to be the most important day of the Jewish year-cycle (not counting Shabbat) and fasting as a means of repentance is expected of every Jewish man or woman above the age of bar mitzvah and bat mitzvah respectively. This is the only fast day mentioned in the Torah (Leviticus 23:26-32). It is so important to fast on this day, that only those who would be put in mortal danger by fasting are exempt, such as the ill or frail (endangering a life is against a core principle of Judaism); such people are actually forbidden from fasting. Those that do eat on this day are encouraged to eat as little as possible at a time and to avoid a full meal. For some, fasting on Yom Kippur is considered more important than the prayers of this holy day. If one fasts, even if one is at home in bed, one is considered as having participated in the full religious service.
The second major day of fasting is Tisha B'Av, the day approximately 2500 years ago on which the Babylonians destroyed the first Holy Temple in Jerusalem, as well as on which the Romans destroyed the second Holy Temple in Jerusalem about 2000 years ago, and later after the Bar Kokhba revolt when the Jews were banished from Jerusalem, the day of Tisha B'Av was the one allowed exception. Tisha B'Av ends a three-week mourning period beginning with the fast of the 17th of Tammuz. This is also the day when observant Jews remember the many tragedies which have befallen the Jewish people, including the Holocaust.
Tisha B'Av and Yom Kippur are the major fasts and are observed from sunset to the following day's dusk. The remaining four fasts are considered minor. Fasting is only observed from sunrise to dusk, and there is more leniency if the fast represents too much of a hardship to a sick or weak person, or pregnant or nursing woman.
The four public but minor fast days are:
The Fast of Gedaliah on the day after Rosh Hashanah
The Fast of the 10th of Tevet
The Fast of the 17th of Tammuz
The Fast of Esther, which takes place immediately before Purim
There are other minor customary fast days, but these are not universally observed, and they include:
"Bahav," (literally an acronym for "Monday, Thursday, Monday") a Monday, Thursday, and the following Monday in the months Cheshvan and Iyar.
"Yom Kippur Katan," (literally "Little Yom Kippur") the day before every Rosh Chodesh, moved back to Thursday if that day is Saturday
The Fast of the Firstborn, on the day before Passover, which applies only to first-born sons; this obligation is usually avoided by participating in a siyum and ritual meal that takes precedence over fasting.
It is an Ashkenazic tradition for a bride and groom to fast on their wedding day before the ceremony as the day represents a personal Yom Kippur. In some congregations, repentance prayers that are said on Yom Kippur service are included by the bride and groom in their private prayers before the wedding ceremony.
Aside from these official days of fasting, Jews may take upon themselves personal or communal fasts, often to seek repentance in the face of tragedy or some impending calamity. For example, a fast is sometimes observed if a sefer torah is dropped. The length of the fast varies, and some Jews will reduce the length of the fast through tzedakah, or charitable acts. Mondays and Thursdays are considered especially auspicious days for fasting. Traditionally, one also fasted upon awakening from an unexpected bad dream although this tradition is rarely kept nowadays.
In the time of the Talmud, drought seems to have been a particularly frequent inspiration for fasts. In modern times as well the Israeli Chief Rabbinate has occasionally declared fasts in periods of drought.
Mandaeism
In Mandaeism, fasting is referred to as ṣauma (). Although ṣauma can refer to physical fasting, it is more often used in Mandaeism to refer to spiritual piety and abstaining from sin.
Pre-Columbian Americas
Refraining from food and water with religious purposes has been practiced over the centuries by many Indigenous groups throughout Mesoamerica as part of ceremonial life. Most of the literature around this topic falls under the broader ethnological category of sacrifice, which has been studied broadly by scholars.
Apart from refraining from ingesting food, fasting may involve restrictions such as drinking water or consuming food at specific times, and omitting salt or chile from all food. Sexual abstinence frequently accompanies fasting, and both practices may last periods as short as three days or as long as a year. The ritual expectations around fasting are conditioned by age, gender, kinship ties, social position, and specific ceremonial contexts. For example, sometimes these restrictions are required of persons before they assume ritual posts or perform specific ceremonial obligations. Fasting and sexual abstinence are often observed by all participants in certain rituals—such as those performed to bring rain for planting maize or to end a drought—by those departing on pilgrimages to sacred places, and among extended kinship networks during curing ceremonies. These practices may be necessary before people ingest ritual foods or other substances and before they handle ritual objects or religious images.
In Mesoamerican cultures, human action is regarded as a necessary complement to divine and natural forces in order to achieve specific objectives, such as the beginning or cessation of annual rains, the productivity of a harvest, harmonious relations between the living and the dead, and fertility among humans and domestic animals.
Catherine Good has argued that many Mesoamerican rituals are based on the concept of vital energy, which circulates among humans, the souls of the dead, elements of the natural world, sacred places, and ritual objects, including Roman Catholic saints. Consuming certain foods and plants, and abstaining from sexual relations enables humans to capture, control, and channel the flow of this energy to desired ends.
Sikhism
Sikhism does not regard fasting as a spiritual act. Fasting as an austerity or as a mortification of the body by means of wilful hunger is discouraged in Sikhism. Sikhism encourages temperance and moderation in food, i.e., neither starve nor over-eat.
Sikhism does not promote fasting except for medical reasons. The Sikh Gurus discourage the devotee from engaging in this ritual as it "brings no spiritual benefit to the person". The Sikh holy Scripture, Sri Guru Granth Sahib tell us: "Fasting, daily rituals, and austere self-discipline – those who keep the practice of these, are rewarded with less than a shell." (Guru Granth Sahib Ang 216).
If you keep fast, then do it a way so that you adopt the compassion, well-being and ask for good will of everyone. "Let your mind be content, and be kind to all beings. In this way, your fast will be successful." (Guru Granth Sahib Ji, Ang 299)
Serve God who alone is your Savior instead indulge into ritual, he is only one who will save you every where: "I do not keep fasts, nor do I observe the month of Ramadaan. I serve only the One, who will protect me in the end. ||1||" (Guru Granth Sahib Ji, Ang 1136)
If you keep fast, to count everyday pledge yourself you will act honest, sincere, controls your desires, mediate. This is a way how you make yourself free of five thieves:
"On the ninth day(naomi) of the month, make a vow to speak the Truth, and your sexual desire, anger and desire shall be eaten up. On the tenth day, regulate your ten doors; on the eleventh day, know that the Lord is One. On the twelfth day, the five thieves are subdued, and then, O Nanak, the mind is pleased and appeased. Observe such a fast as this, O Pandit, O religious scholar; of what use are all the other teachings? ||2||" (Guru Granth Sahib Ji, Ang 1245)
Goal of Human is to meet the Lord-groom, so Guru Sahib Ji says: "One who discards this grain, is practicing hypocrisy. She is neither a happy soul-bride, nor a widow. Those who claim in this world that they live on milk alone, secretly eat whole loads of food. ||3|| Without this grain, time does not pass in peace. Forsaking this grain, one does not meet the Lord of the World." (Guru Granth Sahib Ji, Ang 873)
"Fasting on Ekadashi, adoration of Thakurs (stones) one remains away from Hari engaged in the Maya and omens. Without the Guru's word in the company of Saints one does not get refuge no matter how good one looks." (Bhai Gurdas Ji, Vaar 7)
Taoism
The bigu (辟谷 "avoiding grains") fasting practice originated as a Daoist technique for becoming a xian (仙 "transcendent; immortal"), and later became a Traditional Chinese medicine cure for the sanshi (三尸 "Three Corpses; the malevolent, life-shortening spirits that supposedly reside in the human body"). Chinese interpretations of avoiding gu "grains; cereals" have varied historically; meanings range from not eating particular foodstuffs such as food grain, Five Cereals (China), or staple food to not eating anything such as inedia, breatharianism, or aerophagia.
Yoga
In Yoga principle, it is recommended that one maintains a spiritual fast on a particular day each week (Monday or Thursday). A fast should also be maintained on the full moon day of each month. It is essential on the spiritual fasting day not only to abstain from meals, but also to spend the whole day with a positive, spiritual attitude. On the fasting day, intake of solid food is avoided, with water taken as needed.
Japanese history
Japan has used fasting as punishment for meat consumption. Consumption of domesticated animals was banned by Emperor Tenmu in 675 A.D. from April to September due to Buddhist influences. Wild game was exempt. These laws were regularly flouted. According to the Engishiki, in the Heian Period, fasts began to be used as punishment for the Buddhist sin of meat consumption, initially for 3 days. Eating meat other than seafood, defined here simply as "meat", was seen by Buddhist elite as a kind of spiritually corrupted practice.
By the Kamakura Period, much stricter enforcement and punishments began, with an order from Ise Shrine for a fast for 100 days for eating wild or domestic animals as defined above. Anyone who ate with someone who ate "meat" was required to fast for 21 days. Anyone who ate with someone who ate with someone who consumed "meat" was required to fast for 7 days.
See also
Intermittent fasting
References
Works cited
fast
Diets | Religious fasting | [
"Biology"
] | 11,720 | [
"Behavior",
"Religious practices",
"Human behavior"
] |
71,582,441 | https://en.wikipedia.org/wiki/Maria%20Asensio | Maria C. Asensio is a Spanish-Argentinian physical chemist, academic, researcher, and author. She is a Full Research Professor at the Materials Science Institute of Madrid (ICMM) of the Spanish National Research Council (CSIC) and Chair of the CSIC Research Associated Unit-MATINÉE created between the ICMM and the Institute of Materials Science (ICMUV) of the Valencia University.
Asensio's work is focused on the characterization of advanced materials, developing spectroscopic instrumentation, and the use of artificial intelligence tools for discovering sustainable energy materials. She is best known for her contribution in chemical and electronic imaging of nano- and mesoscopic materials, using nano Angle-Resolved Photoemission Spectroscopy (Nano-ARPES) and X-ray Absorption Spectroscopy (XAS), among other conventional experimental characterization techniques. She has also worked on the experimental determination of the structure of complex materials using effective energy and angular scanning photoelectron Diffraction spectroscopic techniques.
Asensio has published over 250 research articles.
Education
In 1980, Asensio graduated with a degree in physical chemistry from the La Plata National University. From 1981 to 1986, she carried out her doctoral thesis work at the Institute of Theoretical and Applied Physicochemical Research (INIFTA), receiving Ph.D. degree from the National University of La Plata. She earned her postdoctoral degree from the Autonomous University of Madrid in 1987 and Warwick University in 1989.
Career
After moving to Europe, Asensio was an assistant professor at the Autonomous University of Madrid (UAM) from 1988 to 1989 and worked as a Postgraduate lecturer at the European Hercules from 1992 to 1999 at LURE Synchrotron, Orsay, France. She also was a lecturer of the Postgraduate of the Condensed Matter Programme of the Sciences Faculty of the UAM and the Complutense University of Madrid, during 1992 and 1999.
Asensio has been working as a senior scientist at ICMM-CSIC since 1992, with a prolonged leave of eleven years. From 2007 to 2018, she was working as a permanent scientific staff of the Synchrotron SOLEIL, in Gif-sur-Yvette, France.
Asensio was elected as the International Union for Vacuum Science, Technique, and Applications (IUVSTA) Scientific Director from 2004 to 2007. She has chaired the Surface Science Division of the IUVSTA from 2019 to the present. She currently works as a Full Professor Research Staff Member at the Materials Science Institute of Madrid.
Research
Asensio's research is focused on studying the chemical, structural, and electronic structure of surfaces, interfaces, and quantum materials utilizing synchrotron radiation techniques. For several decades, she has worked on the applications and development of scientific instrumentation in Large European Synchrotron Radiation Installations.
Development of synchrotron radiation scientific instrumentation
Asensio has worked on the use, applications, and development of scientific instrumentation in Large European Synchrotron Radiation Installations. After the LURE's closure and the Synchrotron SOLEIL's construction as the new national source of SR, Asensio designed and built an SR station to perform the Nano-ARPES technique. In 2011, the first short scientific article appeared, showing a few incipient advances in the design of the "Nanometre multi-axis manipulator with interferometer control" that later led to the success of the nanoARPES instrument at the ANTARES beamline of the SOLEIL Synchrotron. The results obtained with the instrumentation developed at the ANTARES beamline demonstrated the Project's feasibility, resulting in the proof of concept of the nanoARPES Project. This novel technique is a k-nanoscope technique that allows a direct and precise determination of the electronic structure recording the "with binding energy (BE) vs. k wave vector" plots and Fermi surface imaging of heterogeneous complex materials with a lateral resolution better than 100nm.
Asensio developed a new method entitled the ANTARES beamline of the SOLEIL synchrotron. This method is a multi-axis manipulator with interferometer control and provides an X-ray nanoprobe. She also introduced several ways to characterize the chemical and electronic heterogeneities from the millimetre to the nanometre scale, as well as to address several mesoscopic scientific problems. She used complementary synchrotron and theoretical approaches to address the electrical characteristics of the coordination complex nickel (II) bis-n-propyl xanthate, and to understand the reactivity of coordination chemistry. Later, she conducted ARPES studies on a heterostructure made of bilayer graphene (BLG) and hexagonal boron nitride (hBN), which is back gated with an underlying graphite flake, with submicron spatial resolution among other contributions.
Nanoscience and Nano-ARPES
Asensio's research includes the electronic and chemical characterization of novel low-dimensional quantum materials like Graphene, hBN, transition metal dichalcogenide (TMD), transition metal trichalcogenide (TMT), Xenes, and in particular, silicene and the Nano-ARPES approach, and their atomically controlled homo- and hetero-structures, using conventional and synchrotron radiation-based techniques. Out of all the articles she had, her research on silicene has received the most citations, totalling 3613. She has been focusing on the operation of the Nano-ARPES user facility constructed at the SOLEIL synchrotron over the past ten years. She worked on manybody effects detected by photoemission on low-dimensional materials compilling model photoemission simulation and experimental Nano-ARPES results to unravel collective excitations involving polarons, plasmons, phonons and other low-energy interactions. She analyzed the relationship between the element's wave-function nature and the excited-state, self-energy effects.
Electronic Structures of low-dimensional materials beyond graphene
Asensio has been involved in improving the characteristics of materials and identifying corrosion mechanisms. She discovered the efficiency of scientific instrumentation in permitting realistic solutions for unusually complicated materials. She highlighted the utility of artificially twisted graphene bilayers that are adaptable, affordable building blocks. She conducted an in-depth study about commercially available copper foil that has developed into an effective and affordable catalytic substrate for the scalable synthesis of large-area graphene sheets. She also confirmed the high quality of the individual square graphene sheets and their merged regions by using angle-resolved photoemission spectroscopy with a submicron spatial resolution (Micro-ARPES) to study the three-dimensional electronic structures of square graphene sheets grown on copper foils. In her studies, she analysed the quasi-one-dimensional monophosphate structure of tungsten. She observed three states at the tungsten Fermi level, two of which are two-dimensional and one of which has one-dimensional characteristics. She also untangled the interlayer hybridization of Dirac relativistic carriers in Graphene/MoS2 heterostructures. She clarified the effect of the electron-plasmon coupling on the silicon satellite band structure. She discovered electronic properties of topological insulator nanowires responsible for their quantum transport using high energy and lateral resolution Nano-ARPES, among other contributions to Condensed Matter Physics.
Awards and honors
1986-1987 - Postdoctoral fellowship, CONICET to perform the research work at the UAM
1987- Hans Schumacher Award, Argentine Association for Physicochemical Research (AAIFQ) to the best thesis "Interaction of water with thin Cu films"
1991-1992 - Fellowship, Centre International des Etudiants et Stagiaires (C.I.E.S.) to realize research work at the Synchrotron LURE, Orsay, Ile de France, France.
1992-1993 - Two fellowships were granted by the French "Scientific Research National Center" (CNRS) to support stays at the Synchrotron LURE, Orsay, Ile de France, France.
2004-2007 - Scientific Director of the IUVSTA.
2016–Present - Chair of the Surface Science Section, IUVSTA
2021 - Distinguished visiting lecturer 2021, Nebraska-Lincoln -University
Bibliography
J. Avila, A. Mascaraque, E.G. Michel, M.C. Asensio, Phase transition of submonolayer Pb/Ge(111): α−√3×√3R30° ↔ 3 × 3 at ~250 K, Applied Surface Science. 123–124 (1998) 626–630. Phase transition of submonolayer Pb/Ge(111): α−3×3R30° ↔ 3 × 3 at ~250 K.
M.C. Asensio, J. Avila, L. Roca, A. Tejeda, G.D. Gu, M. Lindroos, R.S. Markiewicz, A. Bansil, Emergence of multiple Fermi surface maps in angle-resolved photoemission from Bi2Sr2CaCu2O8+δ Physical Review B. 67 (2003) 014519–7. DOI Name 10.1103 Values /PhysRevB.67.014519.
P. Vogt, P. De Padova, C. Quaresima, J. Avila, E. Frantzeskakis, M.C. Asensio, A. Resta, B. Ealet, G. Le Lay, Silicene: Compelling Experimental Evidence for Graphenelike Two- Dimensional Silicon, Physical Review Letters. 108 (2012) 155501–5. DOI Name 10.1103 Values /PhysRevLett.108.155501.
J. Avila, M.C. Asensio, First NanoARPES User Facility Available at SOLEIL: An Innovative and Powerful Tool for Studying Advanced Materials, Synchrotron Radiation News. 27 (2014) 24–30. First NanoARPES User Facility Available at SOLEIL: An Innovative and Powerful Tool for Studying Advanced Materials.
L. Brown, E.B. Lochocki, J. Avila, C.-J. Kim, Y. Ogawa, R.W. Havener, D.-K. Kim, E.J. Monkman, D.E. Shai, H.I. Wei, M.P. Levendorf, M. Asensio, K.M. Shen, J. Park, Polycrystalline Graphene with Single Crystalline Electronic Structure, Nano Letters. 14 (2014) 5706–5711. Polycrystalline Graphene with Single Crystalline Electronic Structure.
G. Deokar, J. Avila, I. Razado-Colambo, J.-L. Codron, C. Boyaval, E. Galopin, M.-C. Asensio, D. Vignaud, Towards high quality CVD graphene growth and transfer, Carbon. 89 (2015) 82–92. Towards high quality CVD graphene growth and transfer.
Y. Ma, H.C. Diaz, J. Avila, C. Chen, V. Kalappattil, R. Das, M.-H. Phan, T. Čadež, J.M.P. Carmelo, M.C. Asensio, M. Batzill, Angle resolved photoemission spectroscopy reveals spin charge separation in metallic MoSe2 grain boundary, Nature Communications. 8 (2017) 14231–12. Angle resolved photoemission spectroscopy reveals spin charge separation in metallic MoSe2 grain boundary.
V.L. Nguyen, D.L. Duong, S.H. Lee, J. Avila, G. Han, Y.-M. Kim, M.C. Asensio, S.-Y. Jeong, Y.H. Lee, Layer-controlled single-crystalline graphene film with stacking order via Cu–Si alloy formation, Nat. Nanotechnol. (2020). Layer-controlled single-crystalline graphene film with stacking order via Cu–Si alloy formation.
M. Hallot, B. Caja-Munoz, C. Leviel, O.I. Lebedev, R. Retoux, J. Avila, P. Roussel, M.C. Asensio, C. Lethien, Atomic Layer Deposition of a Nanometer-Thick Li3PO4 Protective Layer on LiNi0.5 Mn1.5O4 Films: Dream or Reality for Long-Term Cycling?, ACS Appl. Mater. Interfaces. (2021) acsami.0c21961. Atomic Layer Deposition of a Nanometer-Thick Li 3 PO 4 Protective Layer on LiNi 0.5 Mn 1.5 O 4 Films: Dream or Reality for Long-Term Cycling?.
M.E. Dávila, J. Ávila, I.R. Colambo, D.B. Putungan, D.P. Woodruff, M.C. Asensio, New insight on the role of localisation in the electronic structure of the Si(111)(7 × 7) surfaces, Sci Rep. 11 (2021) 15034. New insight on the role of localisation in the electronic structure of the Si(111)(7 × 7) surfaces.
References
Living people
1955 births
Women physical chemists
Spanish women scientists
National University of La Plata alumni | Maria Asensio | [
"Chemistry"
] | 2,808 | [
"Women physical chemists",
"Physical chemists"
] |
71,584,886 | https://en.wikipedia.org/wiki/Alan%20Ming-ta%20Wu | Alan Ming-ta Wu (Traditional Chinese: 吳明達; 1938/1939 – 1981) was a Taiwanese-American molecular biologist and immunologist who developed techniques to grow hematopoietic stem cells in cell culture.
Early life and education
Wu was born in Tainan, Taiwan, and attended in Tainan. He obtained his medical degree from National Taiwan University Medical School and served for two years as a medical officer in the Republic of China Army.
Research
Wu conducted research for his PhD in medical biophysics with Till & McCulloch at the Ontario Cancer Institute in Toronto. Wu's PhD work demonstrated the relation between bone marrow and T cells. He was the first to grow stem cells (then called colony forming cells) in cell culture. This allowed Wu to transplant a single cell that generated the entire hematopoietic system in a mouse.
Following his PhD, Wu joined Harrison Echols' lab in the US, performing pioneering work on the regulation of viral genes. They probed the mechanism whereby the cI protein of phage λ represses expression of viral genes through interactions with host RNA polymerase.
In 1971, Wu obtained a position as Senior Scientist at the NIH in Bethesda, Maryland. He collaborated with Bob Gallo on studying how oncogenic viruses replicate, which included studies of reverse transcriptase. Wu applied this knowledge to probe the effects of drugs on mouse tumours induced by oncogenic viruses. He became director of molecular biology at cancer research firm Litton Bionetics Inc.
Wu returned to Toronto in 1976 to take up a position as an Associate Professor of Anatomy. His lab developed techniques for the long-term culture of human T cell progenitors, enabling detailed analysis of T cell biology.
The Institute of Medical Sciences at University of Toronto presents their annual Alan Wu Poster Prize to the most outstanding poster presentations at IMS Scientific Day. This award in honour of Wu notes that "He was well recognized for his research excellence, his passion for science and his strong belief in the value of translational medicine."
Personal details
Wu married Gillian Edwards, a fellow graduate student. They have two sons, Tim Wu and David Wu.
Wu was active in the Taiwan independence movement.
Wu was an avid runner, completing ten marathons in the five years before his death.
Wu died from a brain tumour in 1981.
References
1981 deaths
University of Toronto alumni
Academic staff of the University of Toronto
American academics of Taiwanese descent
American medical researchers
Molecular biologists
National Taiwan University alumni | Alan Ming-ta Wu | [
"Chemistry"
] | 505 | [
"Molecular biologists",
"Biochemists",
"Molecular biology"
] |
71,585,442 | https://en.wikipedia.org/wiki/BL%20Herculis | BL Herculis is a variable star in the northern constellation of Hercules. Its apparent visual magnitude ranges from 9.70 to 10.62, so it is never bright enough to be seen with the naked eye, even with ideal observing conditions. Its distance from the Sun is about 3,850 light-years, and it is moving away from us at 18 km/sec. It is the prototype of the BL Herculis class of variable star, a short-period subset of the pulsating Cepheid variables.
The variability of BL Herculis was discovered by Cuno Hoffmeister, and announced in 1929. Early observations of the star produced a very inaccurate period of 4.2 days, which resulted in peculiar light and radial velocity curves. The first accurate period, 1.3 days, was published by Pavel Parenago in 1940. and a far more precise period of 1.30744185 days was derived from photometric observations in 1983. The descending portion of the star's light curve shows a "bump" (near phase=0.3, with peak brightness phase defined as 0), which models suggest arises from a 2:1 resonance between the fundamental and second overtone pulsation modes. This bump is considered the primary characteristic of BL Her stars, although its position relative to peak brightness varies as a function of the star's period.
The mass of BL Herculis is estimated to be about 0.75 solar masses, just slightly greater than the mass of a typical RR Lyrae variable.
References
Hercules (constellation)
Herculis, BL
347827
088242
BL Herculis variables | BL Herculis | [
"Astronomy"
] | 346 | [
"Hercules (constellation)",
"Constellations"
] |
71,586,096 | https://en.wikipedia.org/wiki/Bis%28allyl%29nickel | Bis(allyl)nickel is an organonickel compound with the formula Ni(η3-C3H5)2. The molecule consists of two allyl ligands bound to nickel(II). It has inversion symmetry. It is a volatile yellow liquid at room temperature.
Preparation and reactions
It can be prepared by the reaction of allyl magnesium bromide with anhydrous nickel chloride. It was first prepared similarly by Gunther Wilke et al. The same group reported that the complex react with carbon monoxide to give nickel tetracarbonyl and 1,5-hexadiene. It catalyzes the trimerization of butadiene. With tertiary phosphines, the complex gives the tetrakis derivative. Such reactions to proceed via the intermediacy of the 18-electron adduct.
References
Organometallic chemistry
Transition metals
Allyl complexes
Coordination chemistry | Bis(allyl)nickel | [
"Chemistry"
] | 185 | [
"Organometallic chemistry",
"Coordination chemistry"
] |
71,586,519 | https://en.wikipedia.org/wiki/Q.%20Jane%20Wang | Qian Jane Wang is an American professor of mechanical engineering and the Executive Director for the Center for Surface Engineering and Tribology at Northwestern University. She is a tribologist whose research includes work on contact mechanics, lubrication, micromechanics, and solid-state batteries.
Education
Wang studied mechanical engineering at the Xi'an University of Technology, graduating in 1982. She went to Northern Illinois University for graduate study in mechanical engineering, and earned a master's degree there in 1989. She completed her Ph.D. in 1993 at Northwestern University. Her doctoral advisor was Herbert S. Cheng.
Research
Wang’s group has developed theories, models, and methods for understanding and simulation of tribological interfaces and for industrial research and development. The scope of the work includes novel design of tribological surfaces, establishment of unified computational methodologies with a focus on efficient computing, establishment of accurate modeling of transient and steady state tribological responses in polymers, and pioneering methods for the tribological response of materials under strain.
Recognition
Wang was named a Fellow of the Society of Tribologists and Lubrication Engineers (STLE) in 2007, and an ASME Fellow in 2009. She won the Ralph R. Teetor Educational Award in 2000
and in 2015 the STLE awarded her the STLE International Award, which is considered their highest technical award. She has also won numerous best-paper awards, and her research publications have been cited more than 12,000 times as of September 2022.
Professional service
Wang's service with STLE includes Chief Editor for the Encyclopedia of Tribology, Chair, 2011-2012, STLE Fellows Committee, Chair, 2011 ASME/STLE International Joint Tribology Conference, and Chair, 2008 STLE Annual Meeting Program Committee.
Wang worked with fellow engineer at Northwestern Yip-Wah Chung to edit the Encyclopedia of Tribology.
References
External links
Home page
Living people
Chinese mechanical engineers
21st-century Chinese women engineers
21st-century Chinese engineers
21st-century American women engineers
21st-century American engineers
American mechanical engineers
Tribologists
Xi'an University of Technology alumni
Northern Illinois University alumni
Northwestern University alumni
Northwestern University faculty
Fellows of the American Society of Mechanical Engineers
Year of birth missing (living people) | Q. Jane Wang | [
"Materials_science"
] | 457 | [
"Tribology",
"Tribologists"
] |
71,587,213 | https://en.wikipedia.org/wiki/Xanthoparmelia%20subramigera | Xanthoparmelia subramigera is a lichen which belongs to the Xanthoparmelia genus.
Description
Grows to around 4-12 cm in diameter with irregularly lobate lobes which are approximately 1.5-4 mm wide. The upper surface of the lichen is yellow-green with a smooth and shiny surface while the lower surface is often pale or medium brown in color.
Habitat and range
The lichen has a wide global range including Africa, North and South America,the Caribbean, Japan, and Oceania. This species can be found in very isolated locations such as Ascension Island and St Helena Island in the Atlantic Ocean and the mountains of North Korea.
See also
List of Xanthoparmelia species
References
subramigera
Lichen species
Lichens described in 1931
Taxa named by Vilmos Kőfaragó-Gyelnik | Xanthoparmelia subramigera | [
"Biology"
] | 176 | [
"Fungus stubs",
"Fungi"
] |
71,587,738 | https://en.wikipedia.org/wiki/Barocaloric%20material | Barocaloric materials are characterized by strong, reversible thermic responses to changes in pressure. Many involve solid-to-solid phase changes from disordered to ordered and rigid under increased pressure, releasing heat. Barocaloric solids undergo solid-to-solid phase change. One barocaloric material processes heat without a phase change: natural rubber.
Input energy
Barocaloric effects can be achieved at pressures above 200 MPa for intermetallics or about 100 MPa in plastic crystals. However, changes phase at pressures of 80 MPa. The hybrid organic–inorganic layered perovskite (CH3–(CH2)n−1–NH3)2MnCl4 (n = 9,10), shows reversible barocaloric entropy change of ΔSr ~ 218, 230 J kg−1 K−1 at 0.08 GPa at 294-311.5 K (transition temperature).
Barocaloric materials are one of several classes of materials that undergo caloric phase transitions. The others are magnetocaloric, electrocaloric, and elastocaloric. Magnetocaloric effects typically require field strengths larger than 2 T, while electrocaloric materials require field strengths in the kV to MV/m range. Elastocaloric materials may require force levels as large as 700 MPa.
Potential applications
Barocaloric materials have potential use as refrigerants in cooling systems instead of gases such as hydrofluorocarbons. cycles, the pressure then drives a solid-to-solid phase change. A prototype air conditioner was made from a metal tube filled with a metal-halide perovskite (the refrigerant) and water or oil (heat/pressure transport material). A piston pressurizes the liquid.
Another project used as the refrigerant. It achieved reversible entropy changes of ~71 J K−1 kg−1 at ambient temperature. The phase transition temperature is a function of pressure, varying at a rate of ~0.79 K MPa−1. The accompanying saturation driving pressure is ~40 MPa, a barocaloric strength of ~1.78 J K−1 kg−1 MPa−1, and a temperature span of ~41 K under 80 MPa. Neutron scattering characterizations of crystal structures/atomic dynamics show that reorientation-vibration coupling is responsible for the pressure sensitivity.
See also
Thermoelectric effect
References
Refrigerants
Phase transitions | Barocaloric material | [
"Physics",
"Chemistry"
] | 513 | [
"Physical phenomena",
"Phase transitions",
"Critical phenomena",
"Phases of matter",
"Statistical mechanics",
"Matter"
] |
71,587,864 | https://en.wikipedia.org/wiki/Silicon%E2%80%93oxygen%20bond | A silicon–oxygen bond ( bond) is a chemical bond between silicon and oxygen atoms that can be found in many inorganic and organic compounds. In a silicon–oxygen bond, electrons are shared unequally between the two atoms, with oxygen taking the larger share due to its greater electronegativity. This polarisation means Si–O bonds show characteristics of both covalent and ionic bonds. Compounds containing silicon–oxygen bonds include materials of major geological and industrial significance such as silica, silicate minerals and silicone polymers like polydimethylsiloxane.
Bond polarity, length and strength
On the Pauling electronegativity scale, silicon has an electronegativity of 1.90 and oxygen 3.44. The electronegativity difference between the elements is therefore 1.54. Because of this moderately large difference in electronegativities, the bond is polar but not fully ionic. Carbon has an electronegativity of 2.55 so carbon–oxygen bonds have an electronegativity difference of 0.89 and are less polar than silicon–oxygen bonds. Silicon–oxygen bonds are therefore covalent and polar, with a partial positive charge on silicon and a partial negative charge on oxygen: Siδ+—Oδ−.
Silicon–oxygen single bonds are longer (1.6 vs 1.4 Å) but stronger (452 vs. about 360 kJ mol−1) than carbon–oxygen single bonds. However, silicon–oxygen double bonds are weaker than carbon–oxygen double bonds (590 vs. 715 kJ mol−1) due to a better overlap of p orbitals forming a stronger pi bond in the latter. This is an example of the double bond rule. For these reasons, carbon dioxide is a molecular gas containing two C=O double bonds per carbon atom whereas silicon dioxide is a polymeric solid containing four Si–O single bonds per silicon atom; molecular SiO2 containing two Si=O double bonds would polymerise. Other compounds containing Si=O double bonds are normally very reactive and unstable with respect to polymerisation or oligomerization. Silanones oligomerise to siloxanes unless they are stabilised, for example by coordination to a metal centre, coordination to Lewis acids or bases, or by steric shielding.
Bond angles
Disiloxane groups, Si–O–Si, tend to have larger bond angles than their carbon counterparts, C–O–C. The Si–O–Si angle ranges from about 130–180°, whereas the C–O–C angle in ethers is typically 107–113°. Si–O–C groups are intermediate, tending to have bond angles smaller than Si–O–Si but larger than C–O–C. The main reasons are hyperconjugation (donation from an oxygen p orbital to an Si–R σ* sigma antibonding molecular orbital, for example) and ionic effects (such as electrostatic repulsion between the two neighbouring partially positive silicon atoms). Recent calculations suggest π backbonding from an oxygen 2p orbital to a silicon 3d orbital makes only a minor contribution to bonding as the Si 3d orbital is too high in energy.
The Si–O–Si angle is 144° in α-quartz, 155° in β-quartz, 147° in α-cristobalite and (153±20)° in vitreous silica. It is 180° in coesite (another polymorph of SiO2), in Ph3Si–O–SiPh3, and in the [O3Si–O–SiO3]6− ion in thortveitite, Sc2Si2O7. It increases progressively from 133° to 180° in Ln2Si2O7 as the size and coordination number of the lanthanide decreases from neodymium to lutetium. It is 150° in hemimorphite and 134° in lithium metasilicate and sodium metasilicate.
Coordination number
In silicate minerals, silicon often forms single bonds to four oxygen atoms in a tetrahedral molecular geometry, forming a silicon–oxygen tetrahedron. At high pressures, silicon can increase its coordination number to six, as in stishovite.
See also
Organosilicon compound
Carbon–hydrogen bond
Carbon–carbon bond
Carbon–fluorine bond
Bonding in solids
References
Chemical bonding | Silicon–oxygen bond | [
"Physics",
"Chemistry",
"Materials_science"
] | 902 | [
"Chemical bonding",
"Condensed matter physics",
"nan"
] |
71,588,049 | https://en.wikipedia.org/wiki/Reanimated%20collaboration | A reanimated collaboration (often shortened to reanimated collab or reanimate) is a type of collaborative fan film, usually involving fan-made animation, typically produced as a tribute to an existing film. The process involves each animator recreating one or more shots of an existing film in their own style. The individual works are then stitched into the original order and published on the internet as a completed collaboration.
This differs from a shot-for-shot recreation, as the goal of a reanimate is to display each of the independent animators' unique stylings rather than to produce a unified or identical result.
Multiple collaborations focus on media made a decade or more prior that receives renewed interest due to internet memes, nostalgia, or the death of a voice actor. As they are often non-profit tributes to an existing work, animators expect to receive little or no profit.
Notable examples
Moon Animate Make-Up! (2014) — Over 250 animators collaborated to reanimate the 38th episode of the DiC English dub of Sailor Moon, "Fractious Friends" (1995). This project is considered to be the first major reanimated internet-collaboration, and eventually led to this style of video increasing in popularity during the late 2010s. As of 2022, the collaboration has over 2.75 million views. A sequel, Moon Animate Make-Up! 2 (2016) reanimated the original Japanese version of the 68th episode, "Protect Chibiusa! Clash of the 10 Warriors" (1993).
Mama Luigi Project (2017) — 227 animators reanimated the 11-minute Super Mario World episode "Mama Luigi" (1991). Each of the 255 total scenes featured a different animation style. It was dedicated to the memories of Canadian actor Tony Rosato, who voiced Luigi, and Canadian actor Harvey Atkin, who voiced King Koopa. This project ultimately generated a resurgence of popularity in reanimated collaborations. The video has 6 million views as of 2022.
The Dover Boys ReAnimated Collab! (2018) - A reanimated collab short film that mark the short's 76th anniversary, a collaborative effort of over 90 independent animators recreated the short scene for scene with each animator drawing in their own style. The reanimated collaboration, titled “The Dover Boys Reanimated Collab!”, was curated by animator Josh 'Zeurel' Palmer and was released on August 27, 2018, on YouTube, receiving nearly three million views.
Steamed Hams but There's a Different Animator Every 13 Seconds (2018) — Andrew Kepple of Albino Blacksheep hosted the project, which reanimated "Steamed Hams," a memorable sequence from the 1996 The Simpsons episode "22 Short Films about Springfield," that had a surge in popularity in the mid-2010s due to internet memes. As of 2024, the video has over 12 million views.
Shrek Retold (2018) — A reanimated collab fan film in which over 200 animators, songwriters, and voice actors recreated Shrek (2001). 3GI is best known for organizing the Shrek-themed festival "Shrekfest" in Milwaukee, WI, held annually from 2014 to 2024. The reanimated collab contains mediums including 2D animation, 3D animation, live action, and stop-motion. Collaborators included David Liebe Hart, Michael Cusack, Ratboy Genius, Anthony Fantano, and SiIvaGunner.
Kirby Reanimated Collab (2019) — Featuring over 300 artists, the project recreated the English dub of Kirby Right Back at Ya! episode 49, "Cartoon Buffoon". The project was directed by Roya Shahidi, and it has received over 3 million views as of 2022. The project was taken down due to DMCA copyright claims multiple times, despite Nintendo claiming it was not behind the takedowns. The video is dedicated to animator Michael "Mikey" McBride (credited as AngelXMikey), who passed away from cystic fibrosis the day it was released.
The Zelda CDi Reanimated Collab! (2020) — PatchToons hosted and released a 21-minute collaboration that recreated the cutscenes of The Legend of Zelda CDi games (1993), which were popularized in the mid-2000s and 2010s with YouTube poop parodies. Over 200 animators collaborated on the project. Nintendo Wire reported, "The ever-shifting mediums and the contrasting animation styles, ranging from professional and sophisticated to intentionally goofy and exaggerated, lend themselves incredibly well to cutscenes that were already chaotic and bizarre to begin with." It was also uploaded to animation website Newgrounds.
Team Fabulous 2 Reanimated (2020) - A collaboration fan short film featuring the work of over 100 animators remaking the late Kitty0706's short film Team Fabulous 2, based on the Valve MMOFPS Team Fortress 2. Most of the scenes were reanimated in 2D, and scenes that were already 2D in the original video were reanimated in 3D with Source Filmmaker 2. The short film was released by TFConnect on 6th July 2020, and as of January 2024, it has amassed 4.8 million views. The short also paid tribute to the late voice actor Rick May, who voiced the Soldier in the game and died from COVID in April 2020. The team also hosted reanimation collabs for the promotional short Meet the Soldier, featuring 2D, 3D, and live-action scenes (the latter of which was unfinished).
The SpongeBob SquarePants Movie: Rehydrated! (2022) — A collaboration fan film between over 300 artists that recreated The SpongeBob SquarePants Movie (2004) as a tribute to late SpongeBob creator Stephen Hillenburg, who died of ALS in 2018. Similarly to Shrek Retold, the audio was re-dubbed and re-instrumented specifically to bypass YouTube's copyright restrictions. Despite this, the video was taken down due to a copyright claim from Paramount within an hour of the video's premiere. This takedown outraged fans and participants of the project, leading to the Twitter hashtag, #JusticeForSpongebob. The video has since been restored to YouTube and has over 2 million views as of 2022.
Shrek 2 Retold (TBA) — A collaboration fan film that was originally announced in an April Fools' Day video titled Shrek 2 Retold, in which the project director discussed the creation of Shrek Retold. Trailers for the project were released during Shrekfest 2019 and on the twentieth anniversary of the original film. The movie premiered at the tenth Shrekfest via an in-person screening at the Oriental Theatre MKE on September 3, 2023. It was then followed up by a panel discussion featuring Quinton Reviews, who contributed to the second remake. The film was announced to be released on YouTube on September 28, 2024. On September 20, 2024, it was announced that the film was delayed indefinitely, and would be released when finished.
See also
Comic jam
Exquisite corpse
Experimental animation
YouTube poop
Fan film
Fan labor
Independent animation
References
Animation
Collaborative projects
Collaboration
Internet-based works
Film and video terminology
2010s in animation
2020s in animation | Reanimated collaboration | [
"Technology"
] | 1,523 | [
"Multimedia",
"Internet-based works"
] |
71,589,706 | https://en.wikipedia.org/wiki/Xanthoparmelia%20joranadia | Xanthoparmelia joranadia is a lichen which belongs to the Xanthoparmelia genus. The lichen is rare and is listed as imperiled by the Nature Conservatory. It is noted for being similar to Xanthoparmelia arida and Xanthoparmelia lecanorica.
Description
It grows to around 3–8 cm in diameter with shiny light yellow-green subirregular lobes that extend 1–2.5 mm wide. It has cylindrical isidia on the upper surface. The lower surface is pale brown. Xanthoparmelia joranadia is a member of the Xanthoparmelia mexicana group, a complex of similar species that differ mainly in their secondary chemistry.
Habitat and range
Found in the North American southwest with a majority of observations occurring in north Mexico and the US state of New Mexico.
Chemistry
Xanthoparmelia joranadia contains lecanoric and usnic acids.
See also
List of Xanthoparmelia species
References
joranadia
Lichen species
Lichens of North America
Fungi described in 1984
Fungus species | Xanthoparmelia joranadia | [
"Biology"
] | 224 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
71,589,820 | https://en.wikipedia.org/wiki/Xanthoparmelia%20arida | Xanthoparmelia arida is a lichen which belongs to the Xanthoparmelia genus. The lichen is an arid shield lichen and is uncommon. It is listed as apparently secure by the Nature Conservatory. It is noted for being similar to Xanthoparmelia joranadia.
Description
Grows to around 3–8 cm in diameter with board dull yellow-green sub irregular lobes that extend 1–3 mm wide. The underside is pale brown with simple rhizines approximately 0.3-0.6 mm long.
Habitat and range
Found in the North American southwest particularly in the US state of Texas.
Chemistry
Xanthoparmelia arida has been recorded containing both Lecanoric and usnic acids.
See also
List of Xanthoparmelia species
References
arida
Lichen species
Lichens of North America
Lichens described in 1979 | Xanthoparmelia arida | [
"Biology"
] | 179 | [
"Fungus stubs",
"Fungi"
] |
71,590,400 | https://en.wikipedia.org/wiki/Carbon%20dichalcogenide | Carbon dichalcogenides are chemical compounds of carbon and chalcogen elements. They have the general chemical formula CZ2, where Z = O, S, Se, Te.
This includes:
Carbon dioxide,
Carbon disulfide,
Carbon diselenide,
Carbonyl sulfide, OCS
Carbonyl selenide, OCSe
Thiocarbonyl selenide, SCSe
Thiocarbonyl telluride, SCTe
Stability
Double bonds between carbon and chalcogen elements, C=Z, become weaker the heavier the chalcogen, Z. This trend means carbon dichalcogenide monomers are less stable and more susceptible to polymerisation as Z changes from O to Te. For example, is stable, polymerises under extreme conditions, tends to polymerise, CSeTe is unstable and does not exist. This trend is an example of the double bond rule.
Bonding
In carbon dichalcogenides, C=O bond lengths are around 1.16 Å, C=S around 1.56 Å, C=Se around 1.70 Å and C=Te around 1.90 Å.
References
Inorganic carbon compounds
Chalcogenides | Carbon dichalcogenide | [
"Chemistry"
] | 240 | [
"Inorganic carbon compounds",
"Inorganic compounds"
] |
71,590,696 | https://en.wikipedia.org/wiki/Subgroup%20distortion | In geometric group theory, a discipline of mathematics, subgroup distortion measures the extent to which an overgroup can reduce the complexity of a group's word problem. Like much of geometric group theory, the concept is due to Misha Gromov, who introduced it in 1993.
Formally, let generate group , and let be an overgroup for generated by . Then each generating set defines a word metric on the corresponding group; the distortion of in is the asymptotic equivalence class of the function where is the ball of radius about center in and is the diameter of .
A subgroup with bounded distortion is called undistorted, and is the same thing as a quasi-isometrically embedded subgroup.
Examples
For example, consider the infinite cyclic group , embedded as a normal subgroup of the Baumslag–Solitar group . With respect to the chosen generating sets, the element is distance from the origin in , but distance from the origin in . In particular, is at least exponentially distorted with base .
On the other hand, any embedded copy of in the free abelian group on two generators is undistorted, as is any embedding of into itself.
Elementary properties
In a tower of groups , the distortion of in is at least the distortion of in .
A normal abelian subgroup has distortion determined by the eigenvalues of the conjugation overgroup representation; formally, if acts on with eigenvalue , then is at least exponentially distorted with base . For many non-normal but still abelian subgroups, the distortion of the normal core gives a strong lower bound.
Known values
Every computable function with at most exponential growth can be a subgroup distortion, but Lie subgroups of a nilpotent Lie group always have distortion for some rational .
The denominator in the definition is always ; for this reason, it is often omitted. In that case, a subgroup that is not locally finite has superadditive distortion; conversely every superadditive function (up to asymptotic equivalence) can be found this way.
In cryptography
The simplification in a word problem induced by subgroup distortion suffices to construct a cryptosystem, algorithms for encoding and decoding secret messages. Formally, the plaintext message is any object (such as text, images, or numbers) that can be encoded as a number . The transmitter then encodes as an element with word length . In a public overgroup with that distorts , the element has a word of much smaller length, which is then transmitted to the receiver along with a number of "decoys" from , to obscure the secret subgroup . The receiver then picks out the element of , re-expresses the word in terms of generators of , and recovers .
References
Geometric group theory
Low-dimensional topology | Subgroup distortion | [
"Physics",
"Mathematics"
] | 573 | [
"Geometric group theory",
"Group actions",
"Low-dimensional topology",
"Topology",
"Symmetry"
] |
71,590,725 | https://en.wikipedia.org/wiki/Socolar%20tiling | A Socolar tiling is an example of an aperiodic tiling, developed in 1989 by Joshua Socolar in the exploration of quasicrystals. There are 3 tiles a 30° rhombus, square, and regular hexagon. The 12-fold symmetry set exist similar to the 10-fold Penrose rhombic tilings, and 8-fold Ammann–Beenker tilings.
The 12-fold tiles easily tile periodically, so special rules are defined to limit their connections and force nonperiodic tilings. The rhombus and square are disallowed from touching another of itself, while the hexagon can connect to both tiles as well as itself, but only in alternate edges.
Dodecagonal rhomb tiling
The dodecagonal rhomb tiling include three tiles, a 30° rhombus, a 60° rhombus, and a square. Another set includes a square, a 30° rhombus and an equilateral triangle.
See also
Pattern block - 6 tiles based on 12-fold symmetry, including the 3 Socolar tiles
Socolar–Taylor tile - A different tiling named after Socolar
References
Aperiodic tilings | Socolar tiling | [
"Physics",
"Mathematics"
] | 250 | [
"Tessellation",
"Geometry",
"Geometry stubs",
"Aperiodic tilings",
"Symmetry"
] |
71,591,647 | https://en.wikipedia.org/wiki/DoITPoMS | Dissemination of IT for the Promotion of Materials Science (DoITPoMS) is a web-based educational software resource designed to facilitate the teaching and learning of Materials science, at the tertiary level for free.
History
The DoITPoMS project originated in the early 1990s, incorporating customized online sources into the curriculum of the Materials Science courses in the Natural Sciences Tripos of the University Cambridge. The initiative became formalized in 2000, with the start of a project supported by the UK national Fund for the Development of Teaching and Learning (FDTL). This was led by the Department of Materials Science and Metallurgy at the University of Cambridge with five partner institutions, including the University of Leeds, London Metropolitan University, the University of Manchester, Oxford Brookes University, and the University of Sheffield. This period of cooperation lasted for about 10 years.
The FDTL project was aimed at building on expertise concerning the use of Information Technology (IT) to enhance the student learning experience and to disseminate these techniques within the Materials Education community in the UK and globally. This was done by creating an archive of background information, such as video clips, micrographs, simulations, etc, and libraries of teaching and learning packages (TLPs) that covers a particular topic, which were designed both for independent usage by students and as a teaching aid for educators. A vital feature of these packages is a high level of user interactivity.
DoITPoMS has no commercial sponsors and no advertising is permitted on the site. The background science to the resources within DoITPoMS has all been input by unpaid volunteers, most of whom have been academics based in universities. A single person retains responsibility for a particular resource, and these people are credited to the site. While the logo of University of Cambridge does appear on the site, is content is available freely and licensed under CC BY-NC-SA 2.0 UK.
Format and usage
The set of resources currently available on the site comprises Libraries of TLPs (~75), Micrographs (~900), Video clips (~150), Lecture demonstration packages (5), and Stand-alone simulations (2). These all have slightly different purposes, and the modes of usage cover a wide range. In each TLP, several simulations typically allow the user to input data to visualise the characteristics of particular effects or phenomena. This is to enable students to explore areas in their way and facilitates the creation of exercises by educators. Each TLP has a set of questions at the end, designed to test whether the main points of the TLP have been understood.
The TLPs cover many diverse topics within the broad field of Materials science, ranging from basics, such as crystal structures and thermal conduction, to more applied areas, such as the design and functioning of batteries and fuel cells. Tools such as X-ray diffraction and the finite element method are also included. Many, although not all, of these topics, go into greater depth and are designed explicitly as educational resources.
Approximately half a million users accessed the site in 2021.
References
External links
DoITPoMS on Flicker.
DoITPoMS on YouTube.
British educational websites
Educational materials
Virtual learning environments
Science communication
Open educational resources
University of Cambridge
Organisations associated with the University of Cambridge | DoITPoMS | [
"Physics",
"Materials_science",
"Engineering"
] | 658 | [
"Applied and interdisciplinary physics",
"Materials science",
"nan"
] |
68,655,524 | https://en.wikipedia.org/wiki/Corrala | A corrala is a type of housing found in old Madrid. Sometimes, it may be called a corridor house due to blocks having doors located on corridors. Usually, it is wooden and the units look at the central area, or a patio.
Most are found in dense and traditional neighborhoods and were built during the 17th, 18th, and 19th centuries.
Some of the blocks are even mentioned in books, like Fortunata y Jacinta. Other blocks can also be found in other Spanish cities, like Cádiz, Granada, Málaga, Seville, Valencia, Valladolid, etc. More cities include Vitoria and Santander and in various towns in Castilla y León and Castilla-La Mancha.
In South America, similar blocks are called Conventillos. Such examples include Santiago de Chile, Valparaíso, Buenos Aires, and Montevideo.
See also
Casa di ringhiera, a similar type of building common in Northern Italy.
Multi-family residential
References
Planned residential developments
House types
Culture in Madrid | Corrala | [
"Engineering"
] | 206 | [
"Architecture stubs",
"Architecture"
] |
68,656,182 | https://en.wikipedia.org/wiki/Bluesky | Bluesky is a microblogging social media service similar to X (formerly Twitter). Users can share short posts containing text, images, and videos. It is owned by Bluesky Social PBC, a benefit corporation based in the United States.
Bluesky was developed as a reference implementation of the AT Protocol, an open communication protocol for distributed social networks. Bluesky Social promotes a composable user experience and algorithmic choice as core features of Bluesky. The platform offers a "marketplace of algorithms" where users can choose or create algorithmic feeds, user-managed moderation and labelling services, and user-made "starter packs" that allow users to quickly follow a large number of related accounts within a community or subculture. The AT Protocol offers a domain name-based handle system within Bluesky, allowing users to self-verify an account's legitimacy and identity by proving ownership of a domain name.
Bluesky began in 2019 as a research initiative at Twitter, becoming an independent company in 2021. Development for the social app accelerated in 2022 after Elon Musk's acquisition of Twitter and subsequent severing of ties between the companies. Bluesky launched as an invite-only service in February 2023 and opened registrations in February 2024. Former Twitter CEO Jack Dorsey left Bluesky Social's board by May 2024. The social media platform grew after October 2024, reaching 20 million users by November 2024.
History
Research initiative
Twitter's then-CEO Jack Dorsey first announced the Bluesky initiative in 2019 on Twitter to explore the possibility of decentralizing Twitter. The stated goal was to find or develop an open and decentralized standard for social media that would give users more control over their data and experience.
Twitter collected a working group of experts in decentralized technology in a Matrix group chat to achieve a consensus on the best path towards decentralization. However, this group did not achieve consensus toward these goals. As a result, Twitter decided to field individual proposals from these experts.
In early 2021, Bluesky was in a research phase, with 50 people from the decentralized technology community active in assessing options and assembling proposals for the protocol. This ultimately led to the hiring of Jay Graber in August 2021 to lead the Bluesky project and the development of the "Authenticated Data Experiment" (ADX), a custom-built protocol made for the purpose of decentralization. Twitter provided $13 million in initial funding to the Bluesky project to begin development.
Incorporation and independence from Twitter
In October 2021, Graber incorporated the Bluesky project as an independent company called "Bluesky Social", and cited Twitter's "very entrenched existing incentives" as a reason to operate independently. Bluesky Social became a benefit corporation in February 2022, with the mission to "develop and drive large-scale adoption of technologies for open and decentralized public conversation". The company's first three employees were hired in March 2022.
After Elon Musk's acquisition of Twitter, Twitter severed all legal and financial ties with Bluesky Social. Musk's takeover did not immediately affect Bluesky Social's operations as a separate entity, but affected its prospects for further funding. Bluesky Social developed the AT Protocol, alongside a reference implementation in the form of a social media service, as a minimum viable product. The company began a waitlist for this service in October 2022.
Invite-only open beta
Bluesky launched as an invite-only iOS beta in February 2023. In April 2023, it was released for Android. Soon after the launch of the Android app, the social network claimed about 50,000 users. Code for the app was made open source under the MIT license in May 2023, with some server software being dual-licensed with the Apache license. Bluesky garnered media attention soon after its launch due to its close association with Twitter and Jack Dorsey.
The social service attracted minority communities and subcultures, including Black, artist, left-wing, transgender, sex worker, and furry communities, who benefited from the invite system. These early communities are often credited for the platform's historically left-leaning culture and its implementation of robust community management and moderation features. Bluesky Social recognized the influence of these early adopters, with Bluesky COO Rose Wang stating that an early goal during the open beta period was to "develop and nurture a set of power users who can help evangelize and help us really tell […] and reinforce the culture" established by these communities.
On July 5, 2023, Bluesky Social announced it had raised $8 million in a seed funding round led by Neo. Bluesky Social pledged to use the funds to grow its team, manage operations, pay for infrastructure costs, and further develop the AT Protocol. The company also announced its conversion to a benefit corporation.
In July 2023, Bluesky experienced a controversy after users discovered the social app did not prevent users from using racial slurs within their handles, as well as the removal of discriminatory slurs from the platform's list of flagged words. This led to a "posting strike" from users, in which users refused to use the app until Bluesky Social addressed the controversy. The controversy led to a public apology from Bluesky Social, an update to the platform's terms of service specifying a prohibition of conduct that "targets people based on their race, gender, religion, ethnicity, nationality, disability, or sexual orientation", and the establishment of a trust and safety team within the company.
In December 2023, Bluesky Social announced a company logo to replace the previous use of a cloudy sky stock image, which was also used as the icon for the official app and website. This icon was a blue butterfly, inspired by existing users' usage of the butterfly emoji to indicate their handles on the service.
Bluesky saw rapid growth during its open beta period, reaching 1 million registered users by September 2023 and surpassing 2 million users in November of that same year. By the time of its public launch in February 2024, the social app had reached over 3 million users.
Public launch
Bluesky opened registrations to the general public on February 6, 2024, a year after its release as an invite-required beta. It opened federation to the social app through the AT Protocol soon afterwards, allowing users to build apps within the protocol and provide their own storage for content sent to Bluesky Social.
Bluesky has experienced several bursts of expansion and contraction following its public launch, mainly in relation to controversies and changes at Twitter. These bursts were referred to as "Elon Musk Events", or EMEs, by developers at Bluesky Social.
Bluesky saw a large influx of registrations by Japanese-speaking users soon after public launch, partly driven by notable Japanese social media personalities such as artist Ui Shigure registering accounts in the platform.
On May 4, 2024, Jack Dorsey, who had initiated and funded the Bluesky research initiative, posted on Twitter that he was no longer on Bluesky Social's board. Bluesky Social confirmed his departure the next day. Dorsey had previously deleted his account from the platform and vouched his support for both Twitter and Nostr, another decentralized protocol. In an interview, Dorsey criticized Bluesky Social, stating that they were "literally repeating all the mistakes [Twitter] made as a company", taking issue with Bluesky Social's company structure and the introduction of moderation tools into the AT Protocol.
In August 2024, following the blocking of Twitter in Brazil, Bluesky gained over 4 million users in under two weeks, becoming the most popular app in the Brazilian App Store and Play Store. Shortly afterwards, on September 16, Bluesky announced it had reached 10 million users. Daily active users in Brazil decreased under 2 million by October.
In October 2024, following changes to Twitter's block feature and Terms of Service to analyze users' content for AI training purposes by default, over 1.2 million users joined Bluesky within two days. On October 24, Bluesky Social announced it had reached 13 million users. It also announced a $15 million Series A financing round led by Blockchain Capital. The company pledged to not integrate cryptocurrency into the social app or the AT Protocol, so as to not "hyperfinancialize the social experience".
Post-election growth
In the weeks following the 2024 United States presidential election on November 5, 2024, in which former president Donald Trump was re-elected for a second, non-consecutive term, millions of Twitter users from the United States, the United Kingdom and Canada joined Bluesky. By November 13, Bluesky had reached 15 million users, growing by around 1 million users per day and reaching the top of the Apple's App Store and Google's Play Store in the United States.
On November 19, Bluesky officially crossed 20 million users, tripling its userbase within 3 months. This surge also triggered a significant uptick of moderation reports with Bluesky Safety noting on November 16, "In the past 24 hours, we have received more than 42,000 reports (an all-time high for one day). We're receiving about 3,000 reports/hour. To put that into context, in all of 2023, we received 360k reports." COO Rose Wang stated that the company's primary focus during the surge was ensuring the platform remained operational while maintaining the integrity of its moderation policies, emphasizing that effective content moderation enhances the user experience.
The major increase in users led to servers being temporarily overloaded, resulting in the platform acquiring more servers. The surge also necessitated a growth in content moderation. While growth was primarily driven by European and American users, popularity of the platform rose in East Asian countries like Japan as well.
Corporate structure
Bluesky Social, officially named Bluesky Social PBC, is a privately-owned for-profit corporation. The company is headquartered in Seattle, Washington, but considers itself "decentralized" without a physical head office. Bluesky Social is a benefit corporation; as such, it is allowed to use its profits for the public good, and is not obligated to maximize shareholder value or return profits to its shareholders as dividends. It is owned by CEO Jay Graber and other Bluesky Social employees. Graber has the largest ownership share of the company. In late 2024, members of the board of directors included Graber, Jeremie Miller, Mike Masnick, and Kinjal Shah.
Funding for operations, as of late 2024, comes primarily from investors and venture capital firms. No advertising is available on the service as of December 2024, and Jay Graber has stated that Bluesky will not "enshittify the network with ads". The company is considering introducing an optional subscription service for users, as well as introducing user-to-user payment services.
Technology
Bluesky unveiled open source code in May 2022 for an early version of its distributed social network protocol, Authenticated Data Experiment (ADX), since renamed the Authenticated Transfer (AT) Protocol. The team opened its early code and placed it under an MIT License so that the development process would be seen in public.
The AT Protocol's initial architecture centers around three main services: a Personal Data Server (PDS), a Relay (previously referred to as a Big Graph Service, or BGS), and an AppView. A PDS is a server which hosts user data in "Data Repositories", which utilize a Merkle tree. The PDS also handles user authentication and manages the signing keys for its hosted repositories. A Relay is described as analogous to an indexer on the web, ingesting repositories from a variety of different PDS hosts and serving them in a single unified stream for other services to ingest. AppViews, meanwhile, are services which consume data from a Relay and can serve it to final users. As of November 2024, most components of the protocol are either only available from Bluesky Social or need to operate with services run by the company to connect to the network, including the main Decentralized Identifier namespace used for almost all accounts that relies on a directory containing all identities and their core information.
While most of the platform's features are available and federated through the AT Protocol, direct messages are offered though a central service outside the AT Protocol that is run by Bluesky Social. The feature is intended to be decentralized with all messages being end-to-end encrypted in the future, with the current iteration intended to be a placeholder for the sake of the user experience.
Posts from the fediverse and most platforms that support it like Mastodon and Threads can be bridged to Bluesky through a tool known as Bridgy Fed.
Features
Bluesky is largely analogous to Twitter in its structure. Users can send 300-character text messages, images, and video in short posts. Users can reply, repost, quote post and like these posts. Frequent users have called posts on the platform "skeets", a portmanteau of "sky" and "tweets", despite CEO Jay Graber's vigorous disapproval of the term.
Bluesky offers a domain name-based handle system via the AT Protocol, allowing users to self-verify an account's legitimacy and identity by proving ownership of a domain name through a DNS text record or HTTPS page. The verification needs to be repeated as a live operation by consumers. The specification doesn't handle changes in status of the domain names.
Bluesky promotes a "marketplace of algorithms" through its Custom Feeds feature, where users can choose or create algorithmic feeds. Bluesky CTO Paul Frazee stated that "In future updates [Bluesky] will make it easy for users to create custom feeds in-app." Third-party tools to publish Custom Feeds on Bluesky have been created by independent developers, including a popular client named Skyfeed.
Bluesky Social claims that an aim to "not be controlled by a single company" is furthered by a composable user experience, "stackable" moderation, and algorithmic choice. The platform offers a "marketplace of algorithms" where users can choose or create algorithmic feeds, user-managed moderation and labelling services, and user-made "starter packs" that allow users to quickly follow a large number of related accounts within a community or subculture.
Bluesky open-sourced its in-house moderation software called "Ozone" in March 2024 for these services.
Bluesky introduced "anti-toxicity" features in August 2024, allowing users to "detach" quote posts from their original post and to hide replies to a user's post. Bluesky also promised the addition of a Community Notes-like feature.
Later, in late December 2024, Bluesky introduced a "Trending Topics" feature in beta. Similar to Twitter and Threads' trending features, this allows users to see words or phrases that are currently unusually popular. This feature, accessible globally, can be found in the right sidebar of the desktop version and in the search button of the mobile application. Currently, it is only available in English. Users can disable it in Settings > Content and Media by unchecking "Enable trending topics". Bluesky respects users' muted words in this feature. With over 25 million users, the social network considers this the first version of the feature and promises future improvements.
Reception
Reviewing the app in February 2023, TechCrunch called it "a functional, if still rather bare-bones, Twitter-like experience".
Lance Ulanoff of TechRadar originally signed up in April 2023 and at the time declared Bluesky "quiet, reserved, thoughtful, or even polite. Overall, BlueSky is the equivalent of a social media Shangri-La." When he revisited it in November 2024 after the post-U.S.-election surge in signups he declared that "for the moment, it's the most exciting place on social media" and "I wasted my day on Bluesky Social and no, I'm not sorry".
Another review posted the same month highlighted key differences between Bluesky and Twitter, particularly in the level of control provided to users. Bluesky allows users to filter content and select algorithms through customizable feeds, and also incorporates features to combat harassment, including a traditional block function and anti-toxicity tools, such as the ability to detach a post from being quoted by others.
Jason Perlow of ZDNet wrote "It's not a direct replacement for Twitter (X), but Bluesky has a lot to offer those who want a fresh start in a decentralized, privacy-minded network." He highlights the claimed decentralized nature of Bluesky, the lack of algorithmic feeds and in a lukewarm manner says that "Bluesky might be worth your time if you're ready to leave algorithm-driven feeds behind and try a network that prioritizes user control."
Parnell Palme McGuinness, a conservative opinion columnist of the Sydney Morning Herald, was critical of the platform, terming it: "a microblogging site for idealists, devoted to protecting them from the raging reality of divergent opinion in a democratic system", a "delicate biosphere of an alternative reality … where "reasonably mainstream opinions attract the ire of the moderators, and are soft-censored as 'intolerance'… not really information so much as a curation of comforting progressive axioms".
See also
Comparison of microblogging and similar services
Comparison of software and protocols for distributed social networking
Notes
References
External links
The AT Protocol website
Internet properties established in 2021
Companies based in Seattle
Distributed computing projects
Social software
Social networking services
Microblogging services
Software using the MIT license
History of Twitter | Bluesky | [
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68,656,707 | https://en.wikipedia.org/wiki/Kedougou%20virus | Kedougou virus (KEDV) is an arbovirus of the Flaviviridae family, genus Flavivirus, belongs to the IV group of a ((+) ssRNA) viruses. The virus was first isolated from Aedes minutus mosquitoes in Senegal in 1971.
KEDV belongs to the Kedougou virus group. It is endemically present in the Kédougou Region, from which it takes its name, together with other arboviruses of the genus Flavivirus such as: Yellow fever virus (YFV), West Nile virus (WNV) and Zika virus (ZIKV). KEDV has also been isolated from Aedes circumluteolus mosquitoes collected in , KwaZulu-Natal, South Africa.
While there is serological evidence for previous infection in humans, and one isolate from humans identified in the Central African Republic, to date no disease has been reported.
References
Flaviviruses | Kedougou virus | [
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68,657,175 | https://en.wikipedia.org/wiki/Dragan%20Damjanovic | Dragan Damjanovic (born 1957 in Sarajevo, Bosnia and Hercegovina, Former Yugoslavia) is a Swiss-Bosnian-Herzegovinian materials scientist. From 2008 to 2022, he was a professor of material sciences at EPFL (École Polytechnique Fédérale de Lausanne) and head of the Group for Ferroelectrics and Functional Oxides.
Career
Damjanovic received a bachelor's degree (summa cum laude) in physics from the University of Sarajevo in 1980. He then joined L. Eric Cross at Pennsylvania State University for a Ph.D. In 1987, he graduated with a thesis in ceramics science titled: "Highly anisotropic electromechanical properties in modified lead titanate ceramics." The Philips Fellowship funded his research. He continued as a research associate at Pennsylvania State University's Materials Research Laboratory. He mainly worked on the pyroelectric properties of synthetic polypeptides, piezoelectric composites for underwater applications, and thermo-optical imagers. In 1991, he joined EPFL's Ceramics Laboratory at the Institute of Materials. Until 2022, he led the Group on Ferroelectrics and Functional Oxides as a professor at EPFL. He taught undergraduate and graduate courses on structure, defects, and electrical properties of materials
Research
Damjanovic investigated physical processes at different driving fields over a wide range of spatial (atomic to macroscopic device size) and time (mHz to GHz) scales. He also studied how those processes affect the macroscopic behavior of ceramics, polymers, single crystals, and thin layers. His current research focuses on oxide perovskites, organometallic lead halide perovskites, and oxides with fluorite structures.
Distinctions
Damjanovic is an IEEE Fellow, a Fellow of the American Ceramic Society, and since 2022 the President-elect of the IEEE Ultrasonics, Frequency Control and Ferroelectrics Society (UFFC-S).
He is the recipient of the 2021 Humboldt Research Award, the 2020 Distinguished Service Award of the IEEE Ultrasonics, Ferroelectrics and Frequency Control Society, the 2018 IEEE Robert E. Newnham Ferroelectrics Award, the 2017 International Award of the Japanese conference on Ferroelectric Materials and Their Applications, the 2009 Rodolphe and René Haenny Award, and the 2009 Ferroelectrics Recognition Award of the IEEE UFFC-S. He was distinguished lecturer for the IEEE UFFC-S in 2010/2011.
Selected works
References
External links
Website of the Group for Ferroelectrics and Functional Oxides
1957 births
Living people
University of Sarajevo alumni
Pennsylvania State University alumni
Academic staff of the École Polytechnique Fédérale de Lausanne
Scientists from Sarajevo
Bosnia and Herzegovina emigrants to Switzerland
21st-century Swiss physicists
20th-century Swiss physicists
Materials scientists and engineers
21st-century Bosnia and Herzegovina people
20th-century Bosnia and Herzegovina people
Fellows of the IEEE
Fellows of the American Ceramic Society | Dragan Damjanovic | [
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68,657,567 | https://en.wikipedia.org/wiki/Biohybrid%20microswimmer | A biohybrid microswimmer also known as biohybrid nanorobot, can be defined as a microswimmer that consist of both biological and artificial constituents, for instance, one or several living microorganisms attached to one or various synthetic parts.
In recent years nanoscopic and mesoscopic objects have been designed to collectively move through direct inspiration from nature or by harnessing its existing tools. Small mesoscopic to nanoscopic systems typically operate at low Reynolds numbers (Re ≪ 1), and understanding their motion becomes challenging. For locomotion to occur, the symmetry of the system must be broken.
In addition, collective motion requires a coupling mechanism between the entities that make up the collective. To develop mesoscopic to nanoscopic entities capable of swarming behaviour, it has been hypothesised that the entities are characterised by broken symmetry with a well-defined morphology, and are powered with some material capable of harvesting energy. If the harvested energy results in a field surrounding the object, then this field can couple with the field of a neighbouring object and bring some coordination to the collective behaviour. Such robotic swarms have been categorised by an online expert panel as among the 10 great unresolved group challenges in the area of robotics. Although investigation of their underlying mechanism of action is still in its infancy, various systems have been developed that are capable of undergoing controlled and uncontrolled swarming motion by harvesting energy (e.g., light, thermal, etc.).
Over the past decade, biohybrid microrobots, in which living mobile microorganisms are physically integrated with untethered artificial structures, have gained growing interest to enable the active locomotion and cargo delivery to a target destination. In addition to the motility, the intrinsic capabilities of sensing and eliciting an appropriate response to artificial and environmental changes make cell-based biohybrid microrobots appealing for transportation of cargo to the inaccessible cavities of the human body for local active delivery of diagnostic and therapeutic agents.
Background
Biohybrid microswimmers can be defined as microswimmers that consist of both biological and artificial constituents, for instance, one or several living microorganisms attached to one or various synthetic parts. The pioneers of this field, ahead of their time, were Montemagno and Bachand with a 1999 work regarding specific attachment strategies of biological molecules to nanofabricated substrates enabling the preparation of hybrid inorganic/organic nanoelectromechanical systems, so called NEMS. They described the production of large amounts of F1-ATPase from the thermophilic bacteria Bacillus PS3 for the preparation of F1-ATPase biomolecular motors immobilized on a nanoarray pattern of gold, copper or nickel produced by electron beam lithography. These proteins were attached to one micron microspheres tagged with a synthetic peptide. Consequently, they accomplished the preparation of a platform with chemically active sites and the development of biohybrid devices capable of converting energy of biomolecular motors into useful work.
One of the most fundamental questions in science is what defines life. Collective motion is one of the hallmarks of life. This is commonly observed in nature at various dimensional levels as energized entities gather, in a concerted effort, into motile aggregated patterns. These motile aggregated events can be noticed, among many others, as dynamic swarms; e.g., unicellular organisms such as bacteria, locust swarms, or the flocking behaviour of birds.
Ever since Newton established his equations of motion, the mystery of motion on the microscale has emerged frequently in scientific history, as famously demonstrated by a couple of articles that should be discussed briefly. First, an essential concept, popularized by Osborne Reynolds, is that the relative importance of inertia and viscosity for the motion of a fluid depends on certain details of the system under consideration. The Reynolds number , named in his honor, quantifies this comparison as a dimensionless ratio of characteristic inertial and viscous forces:
Here, represents the density of the fluid; is a characteristic velocity of the system (for instance, the velocity of a swimming particle); is a characteristic length scale (e.g., the swimmer size); and is the viscosity of the fluid. Taking the suspending fluid to be water, and using experimentally observed values for , one can determine that inertia is important for macroscopic swimmers like fish ( = 100), while viscosity dominates the motion of microscale swimmers like bacteria ( = 10−4).
The overwhelming importance of viscosity for swimming at the micrometer scale has profound implications for swimming strategy. This has been discussed memorably by E. M. Purcell, who invited the reader into the world of microorganisms and theoretically studied the conditions of their motion. In the first place, propulsion strategies of large scale swimmers often involve imparting momentum to the surrounding fluid in periodic discrete events, such as vortex shedding, and coasting between these events through inertia. This cannot be effective for microscale swimmers like bacteria: due to the large viscous damping, the inertial coasting time of a micron-sized object is on the order of 1 μs. The coasting distance of a microorganism moving at a typical speed is about 0.1 angstroms (Å). Purcell concluded that only forces that are exerted in the present moment on a microscale body contribute to its propulsion, so a constant energy conversion method is essential.
Microorganisms have optimized their metabolism for continuous energy production, while purely artificial microswimmers (microrobots) must obtain energy from the environment, since their on-board-storage-capacity is very limited. As a further consequence of the continuous dissipation of energy, biological and artificial microswimmers do not obey the laws of equilibrium statistical physics, and need to be described by non-equilibrium dynamics. Mathematically, Purcell explored the implications of low Reynolds number by taking the Navier-Stokes equation and eliminating the inertial terms:
where is the velocity of the fluid and is the gradient of the pressure. As Purcell noted, the resulting equation — the Stokes equation — contains no explicit time dependence. This has some important consequences for how a suspended body (e.g., a bacterium) can swim through periodic mechanical motions or deformations (e.g., of a flagellum). First, the rate of motion is practically irrelevant for the motion of the microswimmer and of the surrounding fluid: changing the rate of motion will change the scale of the velocities of the fluid and of the microswimmer, but it will not change the pattern of fluid flow. Secondly, reversing the direction of mechanical motion will simply reverse all velocities in the system. These properties of the Stokes equation severely restrict the range of feasible swimming strategies.
Recent publications of biohybrid microswimmers include the use of sperm cells, contractive muscle cells, and bacteria as biological components, as they can efficiently convert chemical energy into movement, and additionally are capable of performing complicated motion depending on environmental conditions. In this sense, biohybrid microswimmer systems can be described as the combination of different functional components: cargo and carrier. The cargo is an element of interest to be moved (and possibly released) in a customized way. The carrier is the component responsible for the movement of the biohybrid, transporting the desired cargo, which is linked to its surface. The great majority of these systems rely on biological motile propulsion for the transportation of synthetic cargo for targeted drug delivery/ There are also examples of the opposite case: artificial microswimmers with biological cargo systems.
Over the past decade, biohybrid microrobots, in which living mobile microorganisms are physically integrated with untethered artificial structures, have gained growing interest to enable the active locomotion and cargo delivery to a target destination. In addition to the motility, the intrinsic capabilities of sensing and eliciting an appropriate response to artificial and environmental changes make cell-based biohybrid microrobots appealing for transportation of cargo to the inaccessible cavities of the human body for local active delivery of diagnostic and therapeutic agents. Active locomotion, targeting and steering of concentrated therapeutic and diagnostic agents embedded in mobile microrobots to the site of action can overcome the existing challenges of conventional therapies. To this end, bacteria have been commonly used with attached beads and ghost cell bodies.
Bacterial biohybrids
Artificial micro and nanoswimmers are small scale devices that convert energy into movement. Since the first demonstration of their performance in 2002, the field has developed rapidly in terms of new preparation methodologies, propulsion strategies, motion control, and envisioned functionality. The field holds promise for applications such as drug delivery, environmental remediation and sensing. The initial focus of the field was largely on artificial systems, but an increasing number of "biohybrids" are appearing in the literature. Combining artificial and biological components is a promising strategy to obtain new, well-controlled microswimmer functionalities, since essential functions of living organisms are intrinsically related to the capability to move. Living beings of all scales move in response to environmental stimuli (e.g., temperature or pH), to look for food sources, to reproduce, or to escape from predators. One of the more well-known living microsystems are swimming bacteria, but directed motion occurs even at the molecular scale, where enzymes and proteins undergo conformational changes in order to carry out biological tasks.
Swimming bacterial cells have been used in the development of hybrid microswimmers. Cargo attachment to the bacterial cells might influence their swimming behavior. Bacterial cells in the swarming state have also been used in the development of hybrid microswimmers. Swarming Serratia marcescens cells were transferred to PDMS-coated coverslips, resulting in a structure referred to as a "bacterial carpet" by the authors. Differently shaped flat fragments of this bacterial carpets, termed "auto-mobile chips", moved above the surface of the microscope slide in two dimensions. Many other works have used Serratia marcescens swarming cells, as well as E. coli swarming cells for the development of hybrid microswimmers. Magnetotactic bacteria have been the focus of different studies due to their versatile uses in biohybrid motion systems.
Protist biohybrids
Algal
Chlamydomonas reinhardtii is a unicellular green microalga. The wild-type C. reinhardtii has a spherical shape that averages about 10 μm in diameter. This microorganism can perceive the visible light and be steered by it (i.e., phototaxis) with high swimming speeds in the range of 100–200 μm s−1. It has natural autofluorescence that permits label-free fluorescent imaging. C. reinhardtii has been actively explored as the live component of biohybrid microrobots for the active delivery of therapeutics. They are biocompatible with healthy mammalian cells, leave no known toxins, mobile in the physiologically relevant media, and allow for surface modification to carry cargo on the cell wall. Alternative attachment strategies for C. reinhardtii have been proposed for the assembly through modifying the interacting surfaces by electrostatic interactions and covalent bonding.
Robocoliths
Collective motion is one of the hallmarks of life. In contrast to what is accomplished individually, multiple entities enable local interactions between each participant to occur in proximity. If we consider each participant in the collective behaviour as a (bio)physical transducer, then the energy will be converted from one type into another. The proxemics will then favour enhanced communication between neighbouring individuals via transduction of energy, leading to dynamic and complex synergetic behaviours of the composite powered structure.
In recent years nanoscopic and mesoscopic objects have been designed to collectively move through direct inspiration from nature or by harnessing its existing tools. Such robotic swarms were categorised by an online expert panel as among the 10 great unresolved group challenges in the area of robotics. Although investigation of their underlying mechanism of action is still in its infancy, various systems have been developed that are capable of undergoing controlled and uncontrolled swarming motion by harvesting energy (e.g., light, thermal, etc.). Importantly, this energy should be transformed into a net force for the system to move.
Small mesoscopic to nanoscopic systems typically operate at low Reynolds numbers (Re ≪ 1), and understanding their motion becomes challenging. For locomotion to occur, the symmetry of the system must be broken.14 In addition, collective motion requires a coupling mechanism between the entities that make up the collective.
To develop mesoscopic to nanoscopic entities capable of swarming behaviour, it has been hypothesised that the entities are characterised by broken symmetry with a well-defined morphology, and are powered with some material capable of harvesting energy. If the harvested energy results in a field surrounding the object, then this field can couple with the field of a neighbouring object and bring some coordination to the collective behaviour.
Emiliania huxleyi (EHUX) coccolithophore-derived asymmetric coccoliths stand out as candidates for the choice of a nano/mesoscopic object with broken symmetry and well-defined morphology. Besides the thermodynamical stability because of their calcite composition, the critical advantage of EHUX coccoliths is their distinctive and sophisticated asymmetric morphology. EHUX coccoliths are characterised by several hammer-headed ribs placed to form a proximal and distal disc connected by a central ring. These discs have different sizes but also allow the coccolith to have a curvature, partly resembling a wagon wheel. EHUX coccoliths can be isolated from EHUX coccolithophores, a unique group of unicellular marine algae that are the primary producers of biogenic calcite in the ocean. Coccolithophores can intracellularly produce intricate three-dimensional mineral structures, such as calcium carbonate scales (i.e., coccoliths), in a process that is driven continuously by a specialized vesicle.
After the process is finished, the formed coccoliths are secreted to the cell surface, where they form the exoskeleton (i.e., coccosphere). The broad diversity of coccolith architecture results in further possibilities for specific applications in nanotechnology or biomedicine. Inanimate coccoliths from EHUX live coccolithophores, in particular, can be isolated easily in the laboratory with a low culture cost and fast reproductive rate and have a reasonably moderate surface area (~20 m2/g) exhibiting a mesoporous structure (pore size in the range of 4 nm).
Presumably, if harvesting of energy is done on both sides of the EHUX coccolith, then it will allow generation of a net force, which means movement in a directional manner. Coccoliths have immense potential for a multitude of applications, but to enable harvesting of energy, their surface properties must be finely tuned. Inspired by the composition of adhesive proteins in mussels, dopamine self-polymerization into polydopamine is currently the most versatile functionalization strategy for virtually all types of materials. Because of its surface chemistry and wide range of light absorption properties, polydopamine is an ideal choice for aided energy harvesting function on inert substrates. In this work, we aim to exploit the benefits of polydopamine coating to provide advanced energy harvesting functionalities to the otherwise inert and inanimate coccoliths. Polydopamine (PDA has already been shown to induce movement of polystyrene beads because of thermal diffusion effects between the object and the surrounding aqueous solution of up to 2 °C under near-infrared (NIR) light excitation. However, no collective behavior has been reported. Here, we prove, for the first time, that polydopamine can act as an active component to induce, under visible light (300–600 nm), collective behavior of a structurally complex, natural, and challenging-to-control architecture such as coccoliths. As a result, the organic-inorganic hybrid combination (coccolith-polydopamine) would enable design of Robocoliths.
Dopamine polymerization proceeds in a solution, where it forms small colloidal aggregates that adsorb on the surface of the coccoliths, forming a confluent film. This film is characterized by high roughness, which translates into a high specific surface area and enhanced harvesting of energy. Because of the conjugated nature of the polymer backbone, polydopamine can absorb light over a broad electromagnetic spectrum, including the visible region.
As a result, the surface of coccoliths is endowed with a photothermal effect, locally heating and creating convection induced by the presence of PDA. This local convection is coupled with another nearby local convection, which allows coupling between individual Robocoliths, enabling their collective motion (Figure 1).
Therefore, when the light encounters the anisometric Robocoliths, they heat locally because of the photothermal conversion induced by the presence of PDA on their surface. The intense local heating produces convection that is different on either side of the Robocolith, causing its observed movement. Such convection can couple with the convection of a neighboring Robocolith, resulting in a "swarming" motion. In addition, the surface of Robocoliths is engineered to accommodate antifouling polymer brushes and potentially prevent their aggregation. Although a primary light-activated convective approach is taken as a first step to understand the motion of Robocoliths, a multitude of mechanistic approaches are currently being developed to pave the way for the next generation of multifunctional Robocoliths as swarming bio-micromachines.
Biomedical applications
Biohybrid microswimmers, mainly composed of integrated biological actuators and synthetic cargo carriers, have recently shown promise toward minimally invasive theranostic applications. Various microorganisms, including bacteria, microalgae, and spermatozoids, have been utilised to fabricate different biohybrid microswimmers with advanced medical functionalities, such as autonomous control with environmental stimuli for targeting, navigation through narrow gaps, and accumulation to necrotic regions of tumor environments. Steerability of the synthetic cargo carriers with long-range applied external fields, such as acoustic or magnetic fields, and intrinsic taxis behaviours of the biological actuators toward various environmental stimuli, such as chemoattractants, pH, and oxygen, make biohybrid microswimmers a promising candidate for a broad range of medical active cargo delivery applications.
Bacteria have a high swimming speed and efficiency in the low Reynolds (Re) number flow regime, are capable of sensing and responding to external environmental signals, and could be externally detected via fluorescence or ultrasound imaging techniques. Due to their inherent sensing capabilities, various bacteria species have been investigated as potential anti-tumor agents and have been the subject of preclinical and clinical trials. The presence of different bacteria species in the human body, such as on the skin and the gut microenvironment, has promoted their use as potential theranostic agents or carriers in several medical applications.
On the other hand, specialised eukaryotic cells, such as red blood cells (RBCs), are one of the nature's most efficient passive carriers with high payload efficiency, deformability, degradability, and biocompatibility, and have also been used in various medical applications. RBCs and RBC-derived nanovesicle, such as nanoerythrosomes, have been successfully adopted as passive cargo carriers to enhance the circulation time of the applied substances in the body, and to deliver different bioactive substances for the treatment of various diseases observed in the liver, spleen and lymph nodes, and also cancer via administrating through intravenous, intraperitoneal, subcutaneous, and inhalational routes. For instance, decreased recognition of drug-loaded particles by immune cells was shown when attached to membranes of the RBCs prior to intravenous injection into mice. Additionally, the altered bioaccumulation profile of nanocarriers was shown when conjugated onto the RBCs, boosting the delivery of nanocarriers to the target organs. It was also reported that the half-life of Fasudil, a drug for pulmonary arterial hypertension, inside the body increased approximately sixfold to eightfold when it was loaded into nanoerythrosomes.
Superior cargo-carrying properties of the RBCs have also generated increased interest for their use in biohybrid microswimmer designs. Recently, active navigation and control of drug and superparamagnetic nanoparticle (SPION)-loaded RBCs were presented using sound waves and magnetic fields. RBCs were further utilized in the fabrication of soft biohybrid microswimmers powered by motile bacteria for active cargo delivery applications. RBCs, loaded with drug molecules and SPIONs, were propelled by bacteria and steered via magnetic fields, which were also capable of traveling through gaps smaller than their size due to the inherent high deformability of the RBCs.
References
Microswimmers
Microorganisms
Robotics | Biohybrid microswimmer | [
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"Chemistry",
"Materials_science",
"Engineering",
"Biology"
] | 4,484 | [
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"Physical phenomena",
"Drug delivery devices",
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"Nanomedicine",
"Motion (physics)",
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] |
68,657,678 | https://en.wikipedia.org/wiki/Applied%20Thai%20architecture | Applied Thai architecture is a movement in Thai architecture which gained popularity, especially for government buildings, during the mid-twentieth century. It arose as a way to signify Thainess, as opposed to following Western traditions, during periods of nationalism beginning during the government of Prime Minister Plaek Phibunsongkhram. The style features the incorporation of certain traditional Thai elements into buildings otherwise following modern plans, usually in the form of high-pitched gabled roofs with simplified forms of traditional ornamentation in concrete. The style has been strongly criticized—Anuwit Charoensupkul in 1969 called it the "cancer of architecture"—and mostly rejected by later architects, though it is still employed in the construction of government buildings, mostly provincial halls and courts.
References
Architecture in Thailand | Applied Thai architecture | [
"Engineering"
] | 160 | [
"Architecture stubs",
"Architecture"
] |
68,657,850 | https://en.wikipedia.org/wiki/Ro07-9749 | Ro07-9749 is a benzodiazepine derivative with sedative and anxiolytic effects, which has been used as an internal standard in the analysis of other benzodiazepines, and also sold as a designer drug.
See also
Flubromazepam
Norflurazepam
Phenazepam
Ro05-4435
References
Designer drugs
2-Fluorophenyl compounds
Benzodiazepines
Iodobenzene derivatives | Ro07-9749 | [
"Chemistry"
] | 103 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
68,659,302 | https://en.wikipedia.org/wiki/Good%20Night%2C%20Sleep%20Tight%20%28Fox%20book%29 | Good Night, Sleep Tight is a 2012 children's picture book by Mem Fox and illustrated by Judy Horacek. It is about Skinny Doug, a babysitter, who uses some nursery rhymes to help his charges, Bonnie and Ben, to sleep.
Publication history
2013, USA, Orchard Books
2012, Australia, Scholastic Australia
Reception
A Booklist review found it "a fun book that will remind parents to pass along the golden oldies".
Good Night, Sleep Tight has also been reviewed by Kirkus Reviews, Publishers Weekly, School Library Journal, Horn Book Guides, The New York Times, Reading Time, Educating Young Children, Scan, and Children's Book and Media Review.
See also
Bonnie and Ben Rhyme Again
References
External links
Library holdings of Good Night, Sleep Tight
"Show and tell", Fox and Horacek discussing the process behind creating Good Night, Sleep Tight
Australian picture books
2012 children's books
Picture books by Mem Fox
Sleep in fiction | Good Night, Sleep Tight (Fox book) | [
"Biology"
] | 194 | [
"Behavior",
"Sleep in fiction",
"Sleep"
] |
68,660,216 | https://en.wikipedia.org/wiki/Catherine%20Chauvel | Catherine Chauvel (born December 27, 1955) is a geochemist at the Institut de Physique du Globe de Paris known for her research on the impact of volcanic activity on the chemistry of the mantle, continental crust, and island arc geochemistry.
Education and career
Chauvel has earned her Ph.D. in geochemistry in 1982 working with Bor-ming Jahn at the University of Rennes. Following her Ph.D., Chauvel was a postdoctoral investigator at the Max Planck Institute in Mainz, Germany from 1982 until 1990. In 1990 she began a French National Centre for Scientific Research (CNRS) position at the University of Rennes where she was promoted to Directeur de Recherche in 1998. From 1999 until 2017, she was at the University Grenoble Alpes in Grenoble, and in 2018 she moved to Institut de Physique du Globe de Paris.
In 2011, Chauvel was elected a fellow of the American Geophysical Union who cited her "for key contributions to understanding mantle evolution by isotope studies of oceanic basalts and linking subducted sediments to arc magmas". From 2015 until 2015, Chauvel was the president of the Volcanology, Geochemistry, and Petrology section of the American Geophysical Union. Starting in 2014, Chauvel has served as one of the editors-in-chief for the journal Chemical Geology.
Research
Chauvel uses geochemistry to examine how terrestrial rocks are formed, and the long-term changes in the mantle and crust. Her Ph.D. research examined neodymium and strontium isotopes and trace elements in the Massif Central, in France. Her subsequent research used neodymium isotopes to date continental crust in Canada and komatiites at Kambalda, Western Australia. In French Polynesia, Chauvel linked multiple components of the mantle to define processes happening beneath the surface. On mid-ocean ridges, Chauvel has examined the movement of lead within the oceanic crust. Chauvel's research using hafnium and neodymium isotopes in oceanic basalt determined the composition of material which is recycled in the subsurface. Following the April 2019 fire at Notre Dame, Chauvel was part of the group that used lead levels in honey to track the fallout from the burned material. The lead concentrations were higher in the down wind areas, and lead isotopes tagged the lead as originating from the fire and not other potential sources of pollutants.
Selected publications
Awards and honors
Fellow, American Geophysical Union (2011)
Fellow, European Association of Geochemistry and Geochemical Society (2017)
Daly lecture, American Geophysical Union (2017)
References
External links
Fellows of the American Geophysical Union
Living people
Women geochemists
French geochemists
University of Rennes alumni
1955 births | Catherine Chauvel | [
"Chemistry"
] | 578 | [
"Geochemists",
"French geochemists",
"Women geochemists"
] |
68,660,251 | https://en.wikipedia.org/wiki/Surface%20Go%203 | The Surface Go 3 is the third generation model of the Surface Go series of devices, introduced as the successor to the Surface Go 2 by Microsoft at their Surface Event on September 22, 2021. It was announced by the company alongside the Surface Laptop Studio, Surface Pro 8, Surface Duo 2 and many Surface accessories. The tablet has the same body, the same set of cameras and speakers, the same ports, and the same dimensions as its predecessor; the main enhancement is a range of more powerful processors. The tablet is powered by the Windows 11 operating system.
Configuration
At launch, the Surface Go 3 was only available in one color option, platinum. A matte black color was made available on January 11, 2022 for all 8GB models. The Wi-Fi models of the tablet started shipping on October 5, 2021, while the LTE models shipped in December 2021 in North America and in Q1 2022 in other markets.
Features
Windows 11 operating system
10th Gen Intel Core i3 or Pentium Gold processor (dual-core Amber Lake-Y)
10.5 inch 1920 x 1280 display
Windows Hello with IR camera for facial recognition logon
Intel UHD Graphics 615 GPU
4 GB and 8 GB RAM options
64 GB, 128 GB, and 256 GB storage options
A headphone jack, USB-C port, microSD card slot, and a nano SIM card tray on LTE models
All configurations can be upgraded to Windows 11 for free or Windows 11 Pro at an additional cost
The 8.3 mm thick tablet weighs 544 grams (1.2 pounds).
Hardware
The Surface Go 3 is the 6th addition to the lightweight 2-in-1 Surface lineup. The Surface Go 3 is aimed toward children and students. The tablet features the same magnesium alloy chassis and screen size as its predecessor. It has one of two fanless dual-core Amber Lake-Y microarchitecture processors, the Intel Core i3-10100Y or Intel Pentium Gold 6500Y. The 6500Y is 60% faster than the previous 4425Y in the Surface Go 2. The device has a USB C port supporting power delivery and a Surface Connect port. The front-facing camera assembly has an infrared sensor that supports login via Windows Hello.
A detachable keyboard uses an 8-pin connection which is compatible with the previous Surface Go models and retails at $99.
Software
Surface Go 3 is powered by Windows 11 Home in S Mode by default with a 30-day trial of Microsoft 365; however, this can be opted out of and upgraded to Home for free or Pro for a fee.
The device also supports Windows Hello login using a biometric facial recognition.
Timeline
References
External links
Tablet computers introduced in 2021
Microsoft Surface
2-in-1 PCs | Surface Go 3 | [
"Technology"
] | 563 | [
"Crossover devices",
"2-in-1 PCs",
"Computing stubs",
"Computer hardware stubs"
] |
68,660,291 | https://en.wikipedia.org/wiki/Surface%20Pro%208 | The Microsoft Surface Pro 8 is a 2-in-1 detachable tablet computer developed by Microsoft to supersede the Surface Pro 7. It combines the form factor and exterior design of the Surface Pro X with internal Intel-based hardware of the Pro 7+. It was announced on September 22, 2021 alongside the Surface Go 3, updated Surface Pro X models, a new Surface Laptop Studio, Surface Duo 2, Surface Slim Pen 2, and several other accessories. The tablet is powered by the new Windows 11 operating system.
On 4 Feb, 2022, Microsoft announced the general availability for organisations across industries in the UAE of its Surface Laptop Studio and Surface Pro 8.
Configurations
Hardware
The Surface Pro 8 is the 10th addition to the Surface Pro lineup preceded by the Surface Pro 7+ and Surface Pro X.
An updated design that aligns closer to the previously launched Surface Pro X.
Intel 11th Gen Core i3, i5, or i7 processors
13-inch touchscreen at 267 PPI, 3:2 aspect ratio, and 120 Hz refresh rate
Up to 1 TB of removable SSD storage
Up to 32 GB of memory
4K video camera support
Unlike previous Surface Pro models, a microSD card slot is not included.
The device is the first Surface Pro to include two USB-C ports with Thunderbolt 4.
Like previous models, the built-in kickstand unfolds from 0 degrees to 165 degrees.
The 51.5 watt-hour battery offers system runtime of up to 16 hours.
Software
Surface Pro 8 is powered by the new Windows 11 Home operating system (Windows 11 Pro or Windows 10 Pro for business models) with a 30-day trial of Microsoft 365. The device also supports Windows Hello login using biometric facial recognition.
Timeline
External links
References
Tablet computers introduced in 2021
Microsoft Surface
2-in-1 PCs | Surface Pro 8 | [
"Technology"
] | 376 | [
"Crossover devices",
"2-in-1 PCs"
] |
68,661,942 | https://en.wikipedia.org/wiki/Methoxyeugenol | Methoxyeugenol is a natural occurring allylbenzene and eugenol derivative. It is found in toxic Japanese star anise pericarp and leaves. as well as in nutmeg crude extract but not in nutmeg essential oil. It also activates PPAR-gamma in vivo.
See also
Acetyleugenol
References
Phenylpropenes
Phenylpropanoids
Secondary metabolites
Methoxy compounds | Methoxyeugenol | [
"Chemistry"
] | 94 | [
"Biomolecules by chemical classification",
"Chemical ecology",
"Phenylpropanoids",
"Secondary metabolites",
"Metabolism"
] |
68,662,735 | https://en.wikipedia.org/wiki/Marshall%20Building | The Marshall Building, formerly known as the Hoffman & Sons Co. Building, is a historic building in Milwaukee, Wisconsin, United States. Part of the Historic Third Ward, the six-story building is the oldest existing example of structural engineer Claude A. P. Turner's Spiral Mushroom System of flat-slab concrete reinforcement.
History
The building was originally constructed as a five story structure in 1906 for John Hoffman & Sons Company, a wholesale grocer specializing in the manufacturing of coffee, tea and spices. When the project was in its early stages of design, Milwaukee consulting engineer John Geist came across an article written by Claude A.P. Turner in Engineering News about a new flat-slab system that Turner had developed for the Johnson-Bovey Building in Minneapolis, Minnesota. He traveled to Minneapolis to observe the load tests for the building and asked Turner to design a similar type of flat-slab system for the building in Milwaukee.
Turner's flat-slab system differed from previous reinforced concrete construction methods in that it consisted of only floor slabs and supporting columns, eliminating the need for beams below the floors. His Spiral Mushroom System, also known as the Turner System, referred to a cage of radial and tangential bars at the top of each column that imparted shear strength to the slab and also provided cantilever support.
A sixth floor was to the structure in 1911 to accommodate the growth in Hoffman's business and was used to accommodate their coffee roasting equipment; however, beginning in the late 1920s the firm began to share space in the building with other manufacturers. The building was purchased in 1947 by developer George Bockl and was renamed the following year after his son Robert Marshall. Bockl sold the building in 1966 but later reacquired it in 1974.
On March 8, 1984, the building became a contributing property of the Historic Third Ward District.
In 2002, the Marshall Building was designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers.
Today the building is primarily used as office space and art galleries.
References
External links
Official website
Buildings and structures in Milwaukee
Historic Civil Engineering Landmarks
Historic district contributing properties in Wisconsin
Industrial buildings completed in 1906
1906 establishments in Wisconsin | Marshall Building | [
"Engineering"
] | 444 | [
"Civil engineering",
"Historic Civil Engineering Landmarks"
] |
68,664,805 | https://en.wikipedia.org/wiki/Isaac%20B.%20Bersuker | Isaac B. Bersuker (Russian: Исаáк Бóрухович (Бори́сович) Берсýкер; born February 12, 1928) is a Romanian-born Soviet-Moldоvan-American theoretical physicist and quantum chemist whose principal research is in chemical physics, solid-state physics, and theoretical chemistry. Known for his "life-long years of experience in theoretical chemistry" working on the electronic structure and properties of coordination compounds, Isaac B. Bersuker is “one of the most widely recognized authorities” in the theory of the Jahn–Teller effect (JTE) and the pseudo-Jahn–Teller effect (PJTE). His accomplishments include explaining the polarization of the atomic core in Rydberg atoms, the effect of tunneling splitting in molecules and solids with a strong JTE, and the discovery of the PJTE origin of ferroelectricity in cubic perovskites. Known as the leading expert in JTE and PJTE, Bersuker is the permanent chairman of the international steering committee of the Jahn–Teller symposia. His present affiliation is with the Oden Institute for Computational Engineering and Science of the Department of Chemistry of the University of Texas at Austin.
Early life, education, and career
Isaac (Izya) Bersuker was born on February 12, 1928, in Chișinău, then part of Greater Romania, to a low-income family of Bessarabian Jewish descent. His father Boruch Bersuker was a carpenter, and his mother Bella Bersuker (Russian: Бéлла Хáймовна Берсýкер, 1896–1981) was a housewife with five kids. As a boy in a family of a modest background, Isaac got his elementary school education in Talmud Torah and ORT. He was 13 years old when the tragic events of World War II forced his Jewish family to run from the Nazis to an Azerbaijan village. Deprived of the traditional middle and high-school education, he spent four years farming in Azerbaijan kolkhoz. However, he never gave up his dream of getting a higher education and becoming an intellectual. After the war, native Romanian, he barely spoke Russian. Yet, in a self-education way, in а two-year term, he managed to complete a four-year high-school program in a Russian school and enrolled at Chișinău State University. In the best meaning of this expression, Isaac is a self-made man. A fascinating autobiographical section in describes "his scientific ascent, starting from a Jewish childhood in Bessarabia and frequently hampered by antisemitic state directives under the Stalin regime." Dedicated to the study of theoretical physics, in 1952, just six years after being an illiterate boy shepherding sheep, Bersuker graduated from this university with a master's degree in physics. He began his scientific research in atomic spectroscopy as a post-graduate student at Leningrad State University, working under Mikhail G. Veselov at the Division of Quantum Mechanics led by its Chair Vladimir A. Fock. Here, in 1957, Bersuker received his doctorate (Kandidat of science, Russian: Кандидáт наýк) and in 1964 his habilitation degree (Doctor of science, Russian: Дóктор наýк). From 1964 to 1993, back in Chișinău, Bersuker continued his scientific research at the Institute of Chemistry of the Moldavian branch of the USSR Academy of Sciences. Organizationally, Bersuker's success was the creation in 1964, and the leadership of the Laboratory of Quantum Chemistry also dubbed ‘‘the Chișinău school of the Jahn–Teller effect.’’ Elected as a Corresponding Member of this academy in 1972 and a full Member in 1989, Isaac B. Bersuker moved to the United States In 1993. He became a senior research scientist and professor of the department of chemistry at the University of Texas at Austin. Isaac B. Bersuker served as a doctoral and habilitation supervisor for 31 post-graduate students and post-docs. According to K. Alex Müller, Bersuker was and still is "in full swing at the university, writing books, discussing with great wit, and quick to understand ‒ as I had known him for well over thirty years." In the late 1980s, owing to Bersuker's high motivating role, leadership, and creative ingenuity, Bersuker's school was called "the capital of the Jahn–Teller effect" by some. Bersuker's academic publications have a high impact on the scientific community. According to Google Scholar, since 1993 when he moved to the United States, Bersuker's papers were cited 10428 times, his h-index is 41, and his i10-index is 141.
Research
Atomic spectroscopy
In his Ph.D. thesis, Bersuker developed the theory of core polarization and its effect on optical transitions in Rydberg atoms. At the time, this was a puzzling problem in absorption spectroscopy. The absorption of light by alkali atoms appeared to violate the electric dipole sum rule. According to Bersuker, the solution to the problem is in the instantaneous polarization of the atomic core by the incident electromagnetic wave creating an additional perturbation to the excitation of the valence electron. Related to this problem, he worked out the adiabatic separation of motion of the valence and the atomic core electrons in electronic structure calculations of atoms. First introduced in 1957, still, decades later, Bersuker's ideas of electron polarization by the incident electromagnetic wave and of the atomic core polarization by the valence electron is used and further explored in atomic spectroscopy.
Jahn–Teller and pseudo Jahn–Teller effects
Bersuker's contributions to the JTE and PJTE theory with applications to physical and chemical phenomena are reflected in his several monographs (some of them written and published with the assistance and involvement of other authors) and major reviews on this subject (see the latest in). First published in 1961–1962, his contributions to the theory of the JTE predicted the tunneling splitting of the vibronic energy levels of the systems with the JTE, later confirmed experimentally. The splitting is due to the tunneling transitions between the equivalent wells on the multiminimum adiabatic potential energy surface produced by this effect. In 1976, "The phenomenon of tunneling splitting of energy levels of polyatomic systems in the state of electronic degeneracy" was qualified as a scientific discovery and registered in the State Register of the USSR (Diploma No. 202). In addition, Bersuker is known for revealing the significance of the PJTE and showing that it may take place at any energy gaps between entangled electronic states. Most important, he proved that the JTE and PJTE are the only sources of structural instability and spontaneous symmetry breaking (SSB) in polyatomic systems. Thus, according to Bersuker, if a polyatomic system has broken symmetry properties, undoubtedly, they are of JTE or PJTE origin. This conclusion elevates the two effects from their assumed earlier rare particular features to general tools for exploring molecular and solid-state properties.
The generality of this result was challenged by the existence of some molecular systems with SSB. For example, in the ozone O3 molecule, neither the JTE nor the PJTE is seen explicitly in the high-symmetry configuration. Bersuker eliminated this controversy by revealing the hidden JTE and PJTE. They take place in the excited states of the system but, being strong enough, penetrate the ground state of the high-symmetry configuration and form an additional, coexisting equilibrium state with lower symmetry. The latter may also have a different spin state leading to an interesting phenomenon of spin-crossover and magnetic-dielectric bistability. Involving excited states, Bersuker also showed that the PJTE is instrumental in explaining the origin of chemical activation and sudden polarization in photochemical reactions. Revealed by Bersuker, other applications of the JTE and PJTE are briefly mentioned below.
Solid-state problems: ferroelectricity and multiferroicity
Another fundamental contribution of Isaac B. Bersuker to the early developments of this field was applying the PJTE to explain the origin of ferroelectricity in perovskite-type crystals. This first application of the PJTE to solve an important solid-state problem led to developing a whole trend in the studies of local and cooperative properties in crystals. The origin of crystals' temperature-controlled spontaneous dielectric polarization was the subject of discussion for many decades involving high-rank physicists at the time. However, with the development of the experimental technics, the "displacive theories" encountered increasing controversies that had no explanation.
Using perovskite crystals as an example, Bersuker showed (first in 1964, published in 1966) that the PJTE produces a spontaneous symmetry breaking resulting under certain conditions in local dipolar instability. It exists in all the crystal phases, and the spontaneous polarization results from the order-disorder interaction between these PJTE-induced local dipolar distortions. Performed in the local octahedral TiO6 center in the BaTiO3 crystal (taken as an example), where vibronic coupling mixes ground 1A1g and close in energy exited 1T1u states of opposite parity (but same multiplicity), detailed analysis with calculations proved the PJTE to produce the dipolar distortion. Thus, it shows that Bersuker's PJTE theory of ferroelectricity agrees with the available empirical data and predicts new properties, confirmed experimentally.
From the fact that PJTE does not entangle states with different spin multiplicity, Bersuker deduced conditions and predicted possible multiferroics in some cubic perovskites. According to Bersuker, only the dn cations with the close-energy ground and excited states of opposite parity, but with the same multiplicity, may meet the necessary conditions of ferroelectricity in the presence of unpaired spins.
Novel solid-state property: orientational polarization
Under external unipolar perturbations, polar gases and liquids manifest two kinds of polarization, displacive and orientational. The latter is by orders of magnitude larger than the former. So far, solids were known to undergo only displacive polarization. Bersuker showed that in ABO3 type perovskites, dipolar distortions are due to the PJTE. Similar to the other cases of the JTE and PJTE, the adiabatic potential energy surface of the metallic B center has eight equivalent wells positioned along the eight diagonals of the cube, meaning eight symmetry-equivalent positions of the PJTE-induced dipole moment with small barriers between them. As a result, these dipoles can rotate under external perturbations realizing orientational polarization. Predicted more than a century ago by P. Debye, solids with intrinsic dipoles behave like polar liquids with orientational polarization. However, enhanced polarizability of such solids was not well understood until Bersuker's works (see also in). As shown by Bersuker, experimentally observed giant flexoelectricity, permittivity, and electrostriction result from PJTE-induced orientational polarization.
Molecular puckering (buckling) and its suppression
Given that the PJTE is the unique source of structural instability, Bersuker applied this idea to planar configurations of some molecules in nondegenerate states. Bersuker was the first to demonstrate that the puckering (or buckling) of planar two-dimensional systems is of PJTE origin. Hence, following Bersuker, their planarity can be driven by external influence targeting the PJTE parameters. As the starting example, he suggested hemoglobin oxygenation. The out-of-plane displacement of the iron atom was shown to be due to the PJTE. At the same time, the coordination of the oxygen atom violates the condition of the PJTE instability, thus restoring the planar configuration. In a more general setup, such manipulations became more critical recently because of the applications of two-dimensional molecular systems in electronics. According to Bersuker, planarity can be operated by targeted redox perturbations, coordination with other atomic groups, and chemical substitutions. A similar modification of a crystal lattice by redox influencing its local JTE centers was also realized.
Other problems
There is quite a list of other theoretical chemistry, chemical physics, and quantum chemistry fields with a remarkable Bersuker's contribution. In a number of his seminal papers, Bersuker introduced and developed theoretical models of vibronic mechanisms in redox properties, electron-conformational effects, chemical reactivity, and catalysis. He is known for revealing the role of JTE and PJTE in the properties of mixed-valence compounds. In addition, he discovered the effect of coordination covalent bonding and the JTE in the "plasticity effect". Also, Bersuker worked out a quantum mechanics/molecular mechanics method of electronic structure calculations of large organometallic systems when there is charge transfer between the QM and MM parts. The name of Bersuker is associated with the semiempirical approach to relativistic electronic structure calculations and a method of estimating molecular-orbital parameters from Mossbauer spectra. In another series of publications, he created and applied the electron-conformational method to computer-aided drug design and toxicology. Within this methodology, the chemical origin of odorant activity was also revealed, including the source of musk odor.
Selected books
Isaac B. Bersuker wrote 15 books, first in 1962, and more than 400 academic papers. His books on the JTE and PJTE, published in 1984, 1989, and 2006, were most influential. According to Google Scholar, cumulatively, these three monographs were cited more than 3000 times.
Bersuker I. B. and Ablov A. V., (1962) Chemical Bonds in Complex Compounds, [in Russian], AN MoldavSSR, Chișinău, 208 p., ASIN: B072L33R79
Bersuker I. B. (1971) ''Structure and Properties of Coordination Compounds'' [in Russian], Khimia, Leningrad, ASIN: B0725HWXD4
Bersuker I. B., (1984) ''The Jahn–Teller Effect and Vibronic Interactions in Modern Chemistry'', Plenum, New York, 320 p.,
Bersuker I. B. and Polinger V. Z. (1989), Vibronic Interactions in Molecules and Crystals, Springer-Verlag, Berlin-Heidelberg-New York, ISBN 978-3-642-83481-3
Bersuker I. B. (2006), The Jahn–Teller Effect, Cambridge University Press, Cambridge (UK), 2006; ISBN 978-0-521-82212-1
Bersuker I. B. (2010). Electronic Structure and Properties of Transition Metal Compounds: Introduction to the theory (2nd ed.), Wiley, Hoboken, NJ, 759 p., ISBN 978-0470180235
Awards and honors
Moldavian SSR State Prize in Science and Technology (1979)
Order of Honor (Moldova) (2004)
The Medal „Scientific Merit”, I class (Moldova) (2021)
Personal life
Isaac B. Bersuker was married in 1951 to Liliya Bersuker (Russian: Ли́лия Бори́совна Берсýкер, 1930–2003), a chemist. He has one son, Gennadi B. Bersuker (born 1953), a theoretical physicist, and two grandsons, Eugene G. Bersuker (born 1979) and Kirill G. Bersuker (born 1985), a molecular biologist.
See also
Jahn–Teller effect
Pseudo Jahn–Teller effect
Vibronic coupling
Adiabatic theorem
Born–Oppenheimer approximation
Symmetry breaking
Coordination Complex
Ferroelectricity
Perovskite
References
1928 births
Living people
Scientists from Chișinău
Bessarabian Jews
Moldova State University alumni
Recipients of the Moldavian SSR State Prize
Recipients of the Order of Honour (Moldova)
University of Texas at Austin faculty
American physicists
Theoretical chemists
Jewish American physicists
American physical chemists
Soviet physicists
Soviet physical chemists
Moldovan chemists
Moldovan physicists | Isaac B. Bersuker | [
"Chemistry"
] | 3,552 | [
"Theoretical chemistry",
"Quantum chemistry",
"Physical chemists",
"Theoretical chemists"
] |
68,665,578 | https://en.wikipedia.org/wiki/Artificial%20Intelligence%20Act | The Artificial Intelligence Act (AI Act) is a European Union regulation concerning artificial intelligence (AI). It establishes a common regulatory and legal framework for AI within the European Union (EU). It came into force on 1 August 2024, with provisions that shall come into operation gradually over the following 6 to 36 months.
It covers all types of AI across a broad range of sectors, with exceptions for AI systems used solely for military, national security, research and non-professional purposes. As a piece of product regulation, it does not confer rights on individuals, but regulates the providers of AI systems and entities using AI in a professional context.
The Act classifies non-exempt AI applications by their risk of causing harm. There are four levels – unacceptable, high, limited, minimal – plus an additional category for general-purpose AI.
Applications with unacceptable risks are banned.
High-risk applications must comply with security, transparency and quality obligations, and undergo conformity assessments.
Limited-risk applications only have transparency obligations.
Minimal-risk applications are not regulated.
For general-purpose AI, transparency requirements are imposed, with reduced requirements for open source models, and additional evaluations for high-capability models.
The Act also creates a European Artificial Intelligence Board to promote national cooperation and ensure compliance with the regulation. Like the EU's General Data Protection Regulation, the Act can apply extraterritorially to providers from outside the EU if they have users within the EU.
Proposed by the European Commission on 21 April 2021, it passed the European Parliament on 13 March 2024, and was unanimously approved by the EU Council on 21 May 2024. The draft Act was revised to address the rise in popularity of generative artificial intelligence systems, such as ChatGPT, whose general-purpose capabilities did not fit the main framework.
Provisions
Risk categories
There are different risk categories depending on the type of application, with a specific category dedicated to general-purpose generative AI:
Unacceptable risk – AI applications in this category are banned, except for specific exemptions. When no exemption applies, this includes AI applications that manipulate human behaviour, those that use real-time remote biometric identification (such as facial recognition) in public spaces, and those used for social scoring (ranking individuals based on their personal characteristics, socio-economic status, or behaviour).
High-risk – AI applications that are expected to pose significant threats to health, safety, or the fundamental rights of persons. Notably, AI systems used in health, education, recruitment, critical infrastructure management, law enforcement or justice. They are subject to quality, transparency, human oversight and safety obligations, and in some cases require a "Fundamental Rights Impact Assessment" before deployment. They must be evaluated both before they are placed on the market and throughout their life cycle. The list of high-risk applications can be expanded over time, without the need to modify the AI Act itself.
General-purpose AI – Added in 2023, this category includes in particular foundation models like ChatGPT. Unless the weights and model architecture are released under free and open source licence, in which case only a training data summary and a copyright compliance policy are required, they are subject to transparency requirements. High-impact general-purpose AI systems including free and open source ones which could pose systemic risks (notably those trained using a computational capability exceeding 1025 FLOPS) must also undergo a thorough evaluation process.
Limited risk – AI systems in this category have transparency obligations, ensuring users are informed that they are interacting with an AI system and allowing them to make informed choices. This category includes, for example, AI applications that make it possible to generate or manipulate images, sound, or videos (like deepfakes).
Minimal risk – This category includes, for example, AI systems used for video games or spam filters. Most AI applications are expected to fall into this category. These systems are not regulated, and Member States cannot impose additional regulations due to maximum harmonisation rules. Existing national laws regarding the design or use of such systems are overridden. However, a voluntary code of conduct is suggested.
Exemptions
Articles 2.3 and 2.6 exempt AI systems used for military or national security purposes or pure scientific research and development from the AI Act.
Article 5.2 bans algorithmic video surveillance only if it is conducted in real time. Exceptions allowing real-time algorithmic video surveillance include policing aims including "a real and present or real and foreseeable threat of terrorist attack".
Recital 31 of the act states that it aims to prohibit "AI systems providing social scoring of natural persons by public or private actors", but allows for "lawful evaluation practices of natural persons that are carried out for a specific purpose in accordance with Union and national law." La Quadrature du Net interprets this exemption as permitting sector-specific social scoring systems, such as the suspicion score used by the French family payments agency Caisse d'allocations familiales.
Governance
The AI Act establishes various new bodies in Article 64 and the following articles. These bodies are tasked with implementing and enforcing the Act. The approach combines EU-level coordination with national implementation, involving both public authorities and private sector participation.
The following new bodies will be established:
AI Office: attached to the European Commission, this authority will coordinate the implementation of the AI Act in all Member States and oversee the compliance of general-purpose AI providers.
European Artificial Intelligence Board: composed of one representative from each Member State, the Board will advise and assist the Commission and Member States to facilitate the consistent and effective application of the AI Act. Its tasks include gathering and sharing technical and regulatory expertise, providing recommendations, written opinions, and other advice.
Advisory Forum: established to advise and provide technical expertise to the Board and the Commission, this forum will represent a balanced selection of stakeholders, including industry, start-ups, small and medium-sized enterprises, civil society, and academia, ensuring that a broad spectrum of opinions is represented during the implementation and application process.
Scientific Panel of Independent Experts: this panel will provide technical advice and input to the AI Office and national authorities, enforce rules for general-purpose AI models (notably by launching qualified alerts of possible risks to the AI Office), and ensure that the rules and implementations of the AI Act correspond to the latest scientific findings.
While the establishment of new bodies is planned at the EU level, Member States will have to designate "national competent authorities". These authorities will be responsible for ensuring the application and implementation of the AI Act, and for conducting "market surveillance". They will verify that AI systems comply with the regulations, notably by checking the proper performance of conformity assessments and by appointing third-parties to carry out external conformity assessments.
Enforcement
The Act regulates the entry to the EU internal market using the New Legislative Framework. It contains essential requirements that all AI systems must meet to access the EU market. These essential requirements are passed on to European Standardisation Organisations, which develop technical standards that further detail these requirements. These standards are developed by CEN/CENELEC JTC 21.
The Act mandates that member states establish their own notifying bodies. Conformity assessments are conducted to verify whether AI systems comply with the standards set out in the AI Act. This assessment can be done in two ways: either through self-assessment, where the AI system provider checks conformity, or through third-party conformity assessment, where the notifying body conducts the assessment. Notifying bodies also have the authority to carry out audits to ensure proper conformity assessments.
Criticism has arisen regarding the fact that many high-risk AI systems do not require third-party conformity assessments. Some commentators argue that independent third-party assessments are necessary for high-risk AI systems to ensure safety before deployment. Legal scholars have suggested that AI systems capable of generating deepfakes for political misinformation or creating non-consensual intimate imagery should be classified as high-risk and subjected to stricter regulation.
Legislative procedure
In February 2020, the European Commission published "White Paper on Artificial Intelligence – A European approach to excellence and trust". In October 2020, debates between EU leaders took place in the European Council. On 21 April 2021, the AI Act was officially proposed by the Commission. On 6 December 2022, the European Council adopted the general orientation, allowing negotiations to begin with the European Parliament. On 9 December 2023, after three days of "marathon" talks, the EU Council and Parliament concluded an agreement.
The law was passed in the European Parliament on 13 March 2024, by a vote of 523 for, 46 against, and 49 abstaining. It was approved by the EU Council on 21 May 2024. It entered into force on 1 August 2024, 20 days after being published in the Official Journal on 12 July 2024. After coming into force, there will be a delay before it becomes applicable, which depends on the type of application. This delay is 6 months for bans on "unacceptable risk" AI systems, 9 months for codes of practice, 12 months for general-purpose AI systems, 36 months for some obligations related to "high-risk" AI systems, and 24 months for everything else.
Reactions
Experts have argued that though the jurisdiction of the law is European, it could have far-ranging implications for international companies that plan to expand to Europe. Anu Bradford at Columbia has argued that the law provides significant momentum to the world-wide movement to regulate AI technologies.
Amnesty International criticized the AI Act for not completely banning real-time facial recognition, which they said could damage "human rights, civil space and rule of law" in the European Union. It also criticized the absence of ban on exporting AI technologies that can harm human rights.
Some tech watchdogs have argued that there were major loopholes in the law that would allow large tech monopolies to entrench their advantage in AI, or to lobby to weaken rules. Some startups welcomed the clarification the act provides, while others argued the additional regulation would make European startups uncompetitive compared to American and Chinese startups. La Quadrature du Net (LQDN) described the AI Act as "tailor-made for the tech industry, European police forces as well as other large bureaucracies eager to automate social control". LQDN described the role of self-regulation and exemptions in the act to render it "largely incapable of standing in the way of the social, political and environmental damage linked to the proliferation of AI".
See also
Algorithmic bias
Ethics of artificial intelligence
Regulation of algorithms
Regulation of artificial intelligence in the European Union
Existential risk from artificial general intelligence
Notes
References
Policies of the European Union
European Digital Strategy
2021 in law
2021 in the European Union
2024 in law
2024 in politics
Data laws of Europe
European Union regulations
Regulation of robots
Regulation of artificial intelligence
2024 in computing | Artificial Intelligence Act | [
"Technology"
] | 2,210 | [
"Computing and society",
"Regulation of artificial intelligence"
] |
68,668,447 | https://en.wikipedia.org/wiki/Kelly%27s%20ZnS | Kelly's is a test statistic that can be used to test a genetic region for deviations from the neutral model, based on the squared correlation of allelic identity between loci.
Details
Given loci and , the Linkage Disequilibrium between these loci, is denoted as
where is the frequency of the alternative allele at i and j co-occurring and and the frequency of the alternative allele at and respectively.
a standardised measure of this is the squared correlation of allelic identity between loci and
Where averages over all pairwise combinations between S loci.
Usage
Inflated scores indicate a deviation from the neutral model and can be used as a potential signature of previous selection
References
Statistical hypothesis testing
Neutral theory | Kelly's ZnS | [
"Biology"
] | 150 | [
"Non-Darwinian evolution",
"Neutral theory",
"Biology theories"
] |
53,098,168 | https://en.wikipedia.org/wiki/Wholeness%20axiom | In mathematics, the wholeness axiom is a strong axiom of set theory introduced by Paul Corazza in 2000.
Statement
The wholeness axiom states roughly that there is an elementary embedding j from the Von Neumann universe V to itself. This has to be stated carefully to avoid Kunen's inconsistency theorem stating (roughly) that no such embedding exists.
More specifically, as Samuel Gomes da Silva states, "the inconsistency is avoided by omitting from the schema all instances of the Replacement Axiom for j-formulas".
Thus, the wholeness axiom differs from Reinhardt cardinals (another way of providing elementary embeddings from V to itself) by allowing the axiom of choice and instead modifying the axiom of replacement.
However, write that Corrazza's theory should be "naturally viewed as a version of Zermelo set theory rather than ZFC".
If the wholeness axiom is consistent, then it is also consistent to add to the wholeness axiom the assertion that all sets are hereditarily ordinal definable.
The consistency of stratified versions of the wholeness axiom, introduced by , was studied by .
References
External links
The Wholeness axiom in Cantor's attic
Large cardinals
Axioms of set theory | Wholeness axiom | [
"Mathematics"
] | 274 | [
"Mathematical objects",
"Infinity",
"Mathematical axioms",
"Axioms of set theory",
"Large cardinals"
] |
53,098,313 | https://en.wikipedia.org/wiki/Generating%20function%20transformation | In mathematics, a transformation of a sequence's generating function provides a method of converting the generating function for one sequence into a generating function enumerating another. These transformations typically involve integral formulas applied to a sequence generating function (see integral transformations) or weighted sums over the higher-order derivatives of these functions (see derivative transformations).
Given a sequence, , the ordinary generating function (OGF) of the sequence, denoted , and the exponential generating function (EGF) of the sequence, denoted , are defined by the formal power series
In this article, we use the convention that the ordinary (exponential) generating function for a sequence is denoted by the uppercase function / for some fixed or formal when the context of this notation is clear. Additionally, we use the bracket notation for coefficient extraction from the Concrete Mathematics reference which is given by .
The main article gives examples of generating functions for many sequences. Other examples of generating function variants include Dirichlet generating functions (DGFs), Lambert series, and Newton series. In this article we focus on transformations of generating functions in mathematics and keep a running list of useful transformations and transformation formulas.
Extracting arithmetic progressions of a sequence
Series multisection provides formulas for generating functions enumerating the sequence given an ordinary generating function where , , and . In the first two cases where , we can expand these arithmetic progression generating functions directly in terms of :
More generally, suppose that and that denotes the primitive root of unity. Then we have the following formula, often known as the root of unity filter:
For integers , another useful formula providing somewhat reversed floored arithmetic progressions are generated by the identity
Powers of an OGF and composition with functions
The exponential Bell polynomials, , are defined by the exponential generating function
The next formulas for powers, logarithms, and compositions of formal power series are expanded by these polynomials with variables in the coefficients of the original generating functions. The formula for the exponential of a generating function is given implicitly through the Bell polynomials by the EGF for these polynomials defined in the previous formula for some sequence of .
Reciprocals of an OGF (special case of the powers formula)
The power series for the reciprocal of a generating function, , is expanded by
If we let denote the coefficients in the expansion of the reciprocal generating function, then we have the following recurrence relation:
Powers of an OGF
Let be fixed, suppose that , and denote . Then we have a series expansion for given by
and the coefficients satisfy a recurrence relation of the form
Another formula for the coefficients, , is expanded by the Bell polynomials as
where denotes the Pochhammer symbol.
Logarithms of an OGF
If we let and define , then we have a power series expansion for the composite generating function given by
where the coefficients, , in the previous expansion satisfy the recurrence relation given by
and a corresponding formula expanded by the Bell polynomials in the form of the power series coefficients of the following generating function:
Faà di Bruno's formula
Let denote the EGF of the sequence, , and suppose that is the EGF of the sequence, . Faà di Bruno's formula implies that the sequence, , generated by the composition , can be expressed in terms of the exponential Bell polynomials as follows:
Integral transformations
OGF ⟷ EGF conversion formulas
We have the following integral formulas for which can be applied termwise with respect to when is taken to be any formal power series variable:
Notice that the first and last of these integral formulas are used to convert between the EGF to the OGF of a sequence, and from the OGF to the EGF of a sequence whenever these integrals are convergent.
The first integral formula corresponds to the Laplace transform (or sometimes the formal Laplace–Borel transformation) of generating functions, denoted by , defined in. Other integral representations for the gamma function in the second of the previous formulas can of course also be used to construct similar integral transformations. One particular formula results in the case of the double factorial function example given immediately below in this section. The last integral formula is compared to Hankel's loop integral for the reciprocal gamma function applied termwise to the power series for .
Example: A double factorial integral for the EGF of the Stirling numbers of the second kind
The single factorial function, , is expressed as a product of two double factorial functions of the form
where an integral for the double factorial function, or rational gamma function, is given by
for natural numbers . This integral representation of then implies that for fixed non-zero and any integral powers , we have the formula
Thus for any prescribed integer , we can use the previous integral representation together with the formula for extracting arithmetic progressions from a sequence OGF given above, to formulate the next integral representation for the so-termed modified Stirling number EGF as
which is convergent provided suitable conditions on the parameter .
Example: An EGF formula for the higher-order derivatives of the geometric series
For fixed non-zero defined such that , let the geometric series over the non-negative integral powers of be denoted by . The corresponding higher-order derivatives of the geometric series with respect to are denoted by the sequence of functions
for non-negative integers . These derivatives of the ordinary geometric series can be shown, for example by induction, to satisfy an explicit closed-form formula given by
for any whenever . As an example of the third OGF EGF conversion formula cited above, we can compute the following corresponding exponential forms of the generating functions :
Fractional integrals and derivatives
Fractional integrals and fractional derivatives (see the main article) form another generalized class of integration and differentiation operations that can be applied to the OGF of a sequence to form the corresponding OGF of a transformed sequence. For we define the fractional integral operator (of order ) by the integral transformation
which corresponds to the (formal) power series given by
For fixed defined such that , we have that the operators .
Moreover, for fixed and integers satisfying we can define the notion of the fractional derivative satisfying the properties that
and
for
where we have the semigroup property that only when none of is integer-valued.
Polylogarithm series transformations
For fixed , we have that (compare to the special case of the integral formula for the Nielsen generalized polylogarithm function defined in)
Notice that if we set , the integral with respect to the generating function, , in the last equation when corresponds to the Dirichlet generating function, or DGF, , of the sequence of provided that the integral converges. This class of polylogarithm-related integral transformations is related to the derivative-based zeta series transformations defined in the next sections.
Square series generating function transformations
For fixed non-zero such that and , we have the following integral representations for the so-termed square series generating function associated with the sequence , which can be integrated termwise with respect to :
This result, which is proved in the reference, follows from a variant of the double factorial function transformation integral for the Stirling numbers of the second kind given as an example above. In particular, since
we can use a variant of the positive-order derivative-based OGF transformations defined in the next sections involving the Stirling numbers of the second kind to obtain an integral formula for the generating function of the sequence, , and then perform a sum over the derivatives of the formal OGF, to obtain the result in the previous equation where the arithmetic progression generating function at hand is denoted by
for each fixed .
Hadamard products and diagonal generating functions
We have an integral representation for the Hadamard product of two generating functions, and , stated in the following form:
where i is the imaginary unit.
More information about Hadamard products as diagonal generating functions of multivariate sequences and/or generating functions and the classes of generating functions these diagonal OGFs belong to is found in Stanley's book. The reference also provides nested coefficient extraction formulas of the form
which are particularly useful in the cases where the component sequence generating functions, , can be expanded in a Laurent series, or fractional series, in , such as in the special case where all of the component generating functions are rational, which leads to an algebraic form of the corresponding diagonal generating function.
Example: Hadamard products of rational generating functions
In general, the Hadamard product of two rational generating functions is itself rational. This is seen by noticing that the coefficients of a rational generating function form quasi-polynomial terms of the form
where the reciprocal roots, , are fixed scalars and where is a polynomial in for all .
For example, the Hadamard product of the two generating functions
and
is given by the rational generating function formula
Example: Factorial (approximate Laplace) transformations
Ordinary generating functions for generalized factorial functions formed as special cases of the generalized rising factorial product functions, or Pochhammer k-symbol, defined by
where is fixed, , and denotes the Pochhammer symbol are generated (at least formally) by the Jacobi-type J-fractions (or special forms of continued fractions) established in the reference. If we let denote the convergent to these infinite continued fractions where the component convergent functions are defined for all integers by
and
where denotes an associated Laguerre polynomial, then we have that the convergent function, , exactly enumerates the product sequences, , for all . For each , the convergent function is expanded as a finite sum involving only paired reciprocals of the Laguerre polynomials in the form of
Moreover, since the single factorial function is given by both and , we can generate the single factorial function terms using the approximate rational convergent generating functions up to order . This observation suggests an approach to approximating the exact (formal) Laplace–Borel transform usually given in terms of the integral representation from the previous section by a Hadamard product, or diagonal-coefficient, generating function. In particular, given any OGF we can form the approximate Laplace transform, which is -order accurate, by the diagonal coefficient extraction formula stated above given by
Examples of sequences enumerated through these diagonal coefficient generating functions arising from the sequence factorial function multiplier provided by the rational convergent functions include
where denotes a modified Bessel function, denotes the subfactorial function, denotes the alternating factorial function, and is a Legendre polynomial. Other examples of sequences enumerated through applications of these rational Hadamard product generating functions given in the article include the Barnes G-function, combinatorial sums involving the double factorial function, sums of powers sequences, and sequences of binomials.
Derivative transformations
Positive and negative-order zeta series transformations
For fixed , we have that if the sequence OGF has derivatives of all required orders for , that the positive-order zeta series transformation is given by
where denotes a Stirling number of the second kind.
In particular, we have the following special case identity when when denotes the triangle of first-order Eulerian numbers:
We can also expand the negative-order zeta series transformations by a similar procedure to the above expansions given in terms of the -order derivatives of some and an infinite, non-triangular set of generalized Stirling numbers in reverse, or generalized Stirling numbers of the second kind defined within this context.
In particular, for integers , define these generalized classes of Stirling numbers of the second kind by the formula
Then for and some prescribed OGF, , i.e., so that the higher-order derivatives of exist for all , we have that
A table of the first few zeta series transformation coefficients, , appears below. These weighted-harmonic-number expansions are almost identical to the known formulas for the Stirling numbers of the first kind up to the leading sign on the weighted harmonic number terms in the expansions.
Examples of the negative-order zeta series transformations
The next series related to the polylogarithm functions (the dilogarithm and trilogarithm functions, respectively), the alternating zeta function and the Riemann zeta function are formulated from the previous negative-order series results found in the references. In particular, when (or equivalently, when in the table above), we have the following special case series for the dilogarithm and corresponding constant value of the alternating zeta function:
When (or when in the notation used in the previous subsection), we similarly obtain special case series for these functions given by
It is known that the first-order harmonic numbers have a closed-form exponential generating function expanded in terms of the natural logarithm, the incomplete gamma function, and the exponential integral given by
Additional series representations for the r-order harmonic number exponential generating functions for integers are formed as special cases of these negative-order derivative-based series transformation results. For example, the second-order harmonic numbers have a corresponding exponential generating function expanded by the series
Generalized negative-order zeta series transformations
A further generalization of the negative-order series transformations defined above is related to more Hurwitz-zeta-like, or Lerch-transcendent-like, generating functions. Specifically, if we define the even more general parametrized Stirling numbers of the second kind by
,
for non-zero such that , and some fixed , we have that
Moreover, for any integers , we have the partial series approximations to the full infinite series in the previous equation given by
Examples of the generalized negative-order zeta series transformations
Series for special constants and zeta-related functions resulting from these generalized derivative-based series transformations typically involve the generalized r-order harmonic numbers defined by
for integers . A pair of particular series expansions for the following constants when is fixed follow from special cases of BBP-type identities as
Several other series for the zeta-function-related cases of the Legendre chi function, the polygamma function, and the Riemann zeta function include
Additionally, we can give another new explicit series representation of the inverse tangent function through its relation to the Fibonacci numbers expanded as in the references by
for and where the golden ratio (and its reciprocal) are respectively defined by .
Inversion relations and generating function identities
Inversion relations
An inversion relation is a pair of equations of the form
which is equivalent to the orthogonality relation
Given two sequences, and , related by an inverse relation of the previous form, we sometimes seek to relate the OGFs and EGFs of the pair of sequences by functional equations implied by the inversion relation. This goal in some respects mirrors the more number theoretic (Lambert series) generating function relation guaranteed by the Möbius inversion formula, which provides that whenever
the generating functions for the sequences, and , are related by the Möbius transform given by
Similarly, the Euler transform of generating functions for two sequences, and , satisfying the relation
is given in the form of
where the corresponding inversion formulas between the two sequences is given in the reference.
The remainder of the results and examples given in this section sketch some of the more well-known generating function transformations provided by sequences related by inversion formulas (the binomial transform and the Stirling transform), and provides several tables of known inversion relations of various types cited in Riordan's Combinatorial Identities book. In many cases, we omit the corresponding functional equations implied by the inversion relationships between two sequences (this part of the article needs more work).
The binomial transform
The first inversion relation provided below implicit to the binomial transform is perhaps the simplest of all inversion relations we will consider in this section. For any two sequences, and , related by the inversion formulas
we have functional equations between the OGFs and EGFs of these sequences provided by the binomial transform in the forms of
and
The Stirling transform
For any pair of sequences, and , related by the Stirling number inversion formula
these inversion relations between the two sequences translate into functional equations between the sequence EGFs given by the Stirling transform as
and
Tables of inversion pairs from Riordan's book
These tables appear in chapters 2 and 3 in Riordan's book providing an introduction to inverse relations with many examples, though which does not stress functional equations between the generating functions of sequences related by these inversion relations. The interested reader is encouraged to pick up a copy of the original book for more details.
Several forms of the simplest inverse relations
Gould classes of inverse relations
The terms, and , in the inversion formulas of the form
forming several special cases of Gould classes of inverse relations are given in the next table.
For classes 1 and 2, the range on the sum satisfies , and for classes 3 and 4 the bounds on the summation are given by . These terms are also somewhat simplified from their original forms in the table by the identities
The simpler Chebyshev inverse relations
The so-termed simpler cases of the Chebyshev classes of inverse relations in the subsection below are given in the next table.
The formulas in the table are simplified somewhat by the following identities:
Additionally the inversion relations given in the table also hold when in any given relation.
Chebyshev classes of inverse relations
The terms, and , in the inversion formulas of the form
for non-zero integers
forming several special cases of Chebyshev classes of inverse relations are given in the next table.
Additionally, these inversion relations also hold when for some or when the sign factor of is shifted from the terms to the terms . The formulas given in the previous table are simplified somewhat by the identities
The simpler Legendre inverse relations
Legendre–Chebyshev classes of inverse relations
The Legendre–Chebyshev classes of inverse relations correspond to inversion relations of the form
where the terms, and , implicitly depend on some fixed non-zero . In general, given a class of Chebyshev inverse pairs of the form
if a prime, the substitution of , , and (possibly replacing ) leads to a Legendre–Chebyshev pair of the form
Similarly, if the positive integer is composite, we can derive inversion pairs of the form
The next table summarizes several generalized classes of Legendre–Chebyshev inverse relations for some non-zero integer .
Abel inverse relations
Abel inverse relations correspond to Abel inverse pairs of the form
where the terms, and , may implicitly vary with some indeterminate summation parameter .
These relations also still hold if the binomial coefficient substitution of is performed for some non-negative integer .
The next table summarizes several notable forms of these Abel inverse relations.
Inverse relations derived from ordinary generating functions
If we let the convolved Fibonacci numbers, , be defined by
we have the next table of inverse relations which are obtained from properties of ordinary sequence generating functions proved as in section 3.3 of Riordan's book.
Note that relations 3, 4, 5, and 6 in the table may be transformed according to the substitutions and for some fixed non-zero integer .
Inverse relations derived from exponential generating functions
Let and denote the Bernoulli numbers and Euler numbers, respectively, and suppose that the sequences, , , and are defined by the following exponential generating functions:
The next table summarizes several notable cases of inversion relations obtained from exponential generating functions in section 3.4 of Riordan's book.
Multinomial inverses
The inverse relations used in formulating the binomial transform cited in the previous subsection are generalized to corresponding two-index inverse relations for sequences of two indices, and to multinomial inversion formulas for sequences of indices involving the binomial coefficients in Riordan.
In particular, we have the form of a two-index inverse relation given by
and the more general form of a multinomial pair of inversion formulas given by
Notes
References
External links
Why don't they teach Newton's calculus of 'What comes next?' - Mathologer
Generating functions | Generating function transformation | [
"Mathematics"
] | 4,015 | [
"Sequences and series",
"Generating functions",
"Mathematical structures"
] |
53,099,706 | https://en.wikipedia.org/wiki/F%20Orionis | The Bayer designation f Orionis is shared by two star systems in the constellation Orion:
f1 Orionis (69 Orionis)
f2 Orionis (72 Orionis)
Orionis, f
Orion (constellation) | F Orionis | [
"Astronomy"
] | 44 | [
"Constellations",
"Orion (constellation)"
] |
53,099,882 | https://en.wikipedia.org/wiki/Eta%20Pictoris | The Bayer designation η Pictoris (Eta Pictoris) is shared by two stars, in the constellation Pictor:
η1 Pictoris (HD 32743)
η2 Pictoris (HD 33042)
Pictoris, Eta
Pictor | Eta Pictoris | [
"Astronomy"
] | 54 | [
"Pictor",
"Constellations"
] |
53,099,942 | https://en.wikipedia.org/wiki/Lambda%20Phoenicis | The Bayer designation λ Phoenicis (Lambda Phoenicis) is shared by two stars, in the constellation Phoenix:
λ1 Phoenicis (HD 2834)
λ2 Phoenicis (HD 3302)
Phoenicis, Lambda
Phoenix (constellation) | Lambda Phoenicis | [
"Astronomy"
] | 60 | [
"Phoenix (constellation)",
"Constellations"
] |
53,100,045 | https://en.wikipedia.org/wiki/Trilaciclib | Trilaciclib, sold under the brand name Cosela, is a medication used to reduce the frequency of chemotherapy-induced bone marrow suppression.
The most common side effects include fatigue; low levels of calcium, potassium and phosphate; increased levels of an enzyme called aspartate aminotransferase; headache; and infection in the lungs (pneumonia).
Trilaciclib may help protect bone marrow cells from damage caused by chemotherapy by inhibiting cyclin-dependent kinase 4/6, a type of enzyme. Trilaciclib is the first therapy in its class and was approved for medical use in the United States in February 2021. The U.S. Food and Drug Administration considers it to be a first-in-class medication.
Chemotherapy drugs are designed to kill cancer cells but can damage normal tissues as well. The bone marrow is particularly susceptible to chemotherapy damage. The bone marrow makes red blood cells, white blood cells, and platelets (small fragments in the blood) that transport oxygen, fight infection, and stop bleeding. When damaged, the bone marrow produces fewer of these cells, leading to fatigue, increased risk of infection, and bleeding, among other problems. Trilaciclib may help protect the normal bone marrow cells from the harmful effects of chemotherapy.
Medical uses
Trilaciclib is indicated to reduce the frequency of chemotherapy-induced bone marrow suppression in adults receiving certain types of chemotherapy for extensive-stage (when the cancer has spread beyond the lungs) small cell lung cancer.
History
The effectiveness of trilaciclib was evaluated in three randomized, double-blind, placebo-controlled studies in participants with extensive-stage small cell lung cancer. Combined, these studies randomly assigned 245 participants to receive either an intravenous infusion of trilaciclib or a placebo before chemotherapy. The studies then compared the two groups for the proportion of participants with severe neutropenia (a very low count of white blood cells called neutrophils) and the duration of severe neutropenia in the first cycle of chemotherapy. In all three studies, participants who received trilaciclib had a lower risk of having severe neutropenia compared to participants who received a placebo. Among those who had severe neutropenia, participants who received trilaciclib, on average, had it for a shorter time than participants who received a placebo.
The U.S. Food and Drug Administration (FDA) granted the application for trilaciclib priority review and breakthrough therapy designations. The FDA granted the approval of Cosela to G1 Therapeutics, Inc.
References
External links
Protein kinase inhibitors
Chemotherapeutic adjuvants
Pyridines
4-Methylpiperazin-1-yl compounds
Spiro compounds
Amides
Guanidines
CDK inhibitors | Trilaciclib | [
"Chemistry"
] | 574 | [
"Guanidines",
"Functional groups",
"Organic compounds",
"Amides",
"Spiro compounds"
] |
53,100,222 | https://en.wikipedia.org/wiki/Triple-twin | The Triple-twin was a type of double vacuum triode for audio power amplifiers. A triple-twin contained two dissimilar, directly coupled triodes in a common envelope. To maximize power yield, the output triode was intended to be positively biased, and thus required substantial grid current. This current was supplied by the input triode, configured as a cathode follower. The cathode of the input triode was hard-wired to the control grid of the output triode inside the envelope.
The first tube of the family, type 295, was introduced by Cable Radio Tube Corporation under the Speed label in March 1932. The company advertised 295 as being twice as powerful as the type 47 pentode, and three times as powerful as the type 45 directly heated triode (the most common output tube of the period) - hence the name triple-twin. Maximum output power reached 4,5 W at 5% distortion into 4 kOhm load; at 2 kOhm and 10 kOhm loads distortion increased to 8%. The 295 required +250 V plate voltage, and around +6 V positive grid bias.
The original type 295 had a directly heated output section, and an indirectly heated input section. The 2B6 tube, introduced in 1933, had similar power ratings, but had both cathodes indirectly heated. The Sylvania 6N6G, introduced in 1936, had both cathodes indirectly heated, and also had the cathode follower resistor hard-wired inside the envelope. A single-ended 6N6G amplifier required only one external component, the output transformer; currents and bias voltages were set by the internal resistor. A push-pull 6N6G amplifier required only two tubes and two transformers (input and output).
Despite massive advertising, the triple-twin was a market failure. The industry preferred general-purpose tube types, and the triple-twin was obsolete by the end of the 1930s.
References
Vacuum tubes
1932 in technology
1932 in radio | Triple-twin | [
"Physics"
] | 410 | [
"Vacuum tubes",
"Vacuum",
"Matter"
] |
53,102,285 | https://en.wikipedia.org/wiki/Mass-spring-damper%20model | The mass-spring-damper model consists of discrete mass nodes distributed throughout an object and interconnected via a network of springs and dampers. This model is well-suited for modelling object with complex material properties such as nonlinearity and viscoelasticity.
Packages such as MATLAB may be used to run simulations of such models. As well as engineering simulation, these systems have applications in computer graphics and computer animation.
Derivation (Single Mass)
Deriving the equations of motion for this model is usually done by summing the forces on the mass (including any applied external forces :
By rearranging this equation, we can derive the standard form:
where
is the undamped natural frequency and is the damping ratio. The homogeneous equation for the mass spring system is:
This has the solution:
If then is negative, meaning the square root will be imaginary and therefore the solution will have an oscillatory component.
See also
Numerical methods
Soft body dynamics#Spring/mass models
Finite element analysis
References
Classical mechanics
Mechanical vibrations | Mass-spring-damper model | [
"Physics",
"Engineering"
] | 207 | [
"Structural engineering",
"Mechanics",
"Classical mechanics",
"Mechanical vibrations"
] |
53,102,766 | https://en.wikipedia.org/wiki/Hemicordulia%20novaehollandiae | Hemicordulia novaehollandiae is not formally recognized as a species of dragonfly by collections in Australia. It was originally described as being in the family Corduliidae from Nouvelle-Hollande (Australia) in 1871 by Edmond de Sélys-Longchamps, and the location of the holotype is unknown.
References
Corduliidae
Insects described in 1871
Nomina dubia | Hemicordulia novaehollandiae | [
"Biology"
] | 82 | [
"Biological hypotheses",
"Nomina dubia",
"Controversial taxa"
] |
53,103,457 | https://en.wikipedia.org/wiki/Configurable%20mixed-signal%20IC | Configurable Mixed-signal IC (abbreviated as CMIC) is a category of ICs comprising a matrix of analog and digital blocks which are configurable through programmable (OTP) non-volatile memory. The technology, in combination with its design software and development kits, allows immediate prototyping of custom mixed-signal circuits, as well as the integration of multiple discrete components into a single IC to reduce PCB cost, size and assembly issues.
See also
Field-programmable analog array
Programmable system-on-chip
References
Integrated circuits | Configurable mixed-signal IC | [
"Technology",
"Engineering"
] | 115 | [
"Computer engineering",
"Integrated circuits"
] |
53,103,843 | https://en.wikipedia.org/wiki/SS%20Empire%20Fowey | Empire Fowey was a ocean liner that was built in 1935 as Potsdam by Blohm & Voss, Hamburg for the Hamburg America Line. She was sold before completion to Norddeutscher Lloyd. While owned by Norddeutscher Lloyd she was one of three sister ships operating the service between Bremen and the Far East. Her sister ships were SS Scharnhorst and SS Gneisenau.
En route to the United States when war was declared, she managed to return to Germany.
Used as an accommodation ship and troopship during World War II, she was seized by the Allies in 1945 and renamed Empire Jewel. She was converted to a troopship in 1946 but her high-pressure boilers proved troublesome and the ship was rebuilt in 1947 and renamed Empire Fowey.
Sold to Pakistan in 1960 and renamed Safina-E-Hujjaj, she served until 1976 when she was scrapped at Gadani Beach, Pakistan.
Description
As built, the ship was long, with a beam of . She had a depth of . She was assessed at , . Accommodation for 286 passengers was provided.
The ship was propelled by two steam turbines, driving electric motors, driving twin screw propellers. The turbines were constructed by Blohm & Voss, Hamburg and the electric motors were by Siemens-Schuckertwerke AG, Berlin. They were rated at 21,000shp. They could propel her at . Steam was supplied by four boilers.
History
The ship was built in 1935 by Blohm & Voss Hamburg, Germany for the Hamburg America Line. She was launched on 16 January 1935. Her port of registry was Hamburg. It was intended to use her on the Hamburg–Southampton–Far East service. Following a decision by Hamburg America Line and Norddeutscher Lloyd to revise the way the two companies worked together, she was sold before completion to Norddeutscher Lloyd. The Code Letters DOQS were allocated. Her port of registry was changed to Bremen.
Completed on 27 June 1935, Potsdam sailed on her maiden voyage on 5 July 1935. The route was Hamburg–Southampton–Palma–Barcelona–Genoa–Colombo–Shanghai–Yokohama. Her maiden voyage was not without problems.
Potsdam was en route to the United States when war was declared. She returned to Germany by sailing around the north coast of Scotland. Requisitioned by the Kriegsmarine, she was initially used as an accommodation ship at Hamburg. Plans to convert her to an aircraft carrier were not carried through. Work started in November 1942 as Project Elbe, but conversion was abandoned in February 1943 after little work had been done by Blohm & Voss. Had she been converted, she would have carried 24 aircraft and been armed with 6 dual 4.1 inch Anti-Aircraft guns, 5 dual 3.7mm Anti-Aircraft guns and 24 to 32 20mm Anti-Aircraft guns.
Potsdam was subsequently used as an accommodation ship at Gdynia, Poland. She was subsequently used as a troopship serving Norwegian and Baltic ports. She participated in the Evacuation of East Prussia. She was seized on 13 May 1945 at Flensburg and was passed to the Ministry of War Transport. Potsdam was renamed Empire Jewel. She arrived at Kiel on 19 June and an armed guard was posted on board to stop the Germans using her to block the Kaiser Wilhelm Kanal. She then sailed to Brunsbüttel where the armed guard left. After three weeks with an all-German crew on board, she sailed on 20 July for Methil, Fife, United Kingdom.
Empire Jewel was renamed Empire Fowey. The United Kingdom Official Number 180810 and Code Letters GMFW were allocated. Her port of registry was changed to London. She was placed under the management of the P&O Line. In July 1945, she was converted to a troopship by Harland & Wolff, Belfast, County Antrim. The work was completed in April 1946. In service, her high-pressure boilers proved troublesome as her crew were not used to this type of boiler. Laid up in November 1946, she was towed to the Clyde in March 1947 and again refitted. New boilers and geared turbines were fitted and her accommodation was again rebuilt. The work was carried out by Alexander Stephens & Sons, Linthouse, Renfrewshire. It took three years to complete at a cost of £3 million. Following the rebuild, she was assessed at . She now had accommodation for 1,636 troops.
In 1951, The King approved a new flag for use by the Ministry of Transport. Empire Fowey was the first ship to fly this flag, which was a defaced Blue Ensign. On 23 April 1955, she ran aground in the Suez Canal but was refloated after twelve hours. In August 1955, there were complaints about the quality of the food served aboard Empire Fowey and also poor ventilation of the vessel. The matter was raised in Parliament by Tom Iremonger, MP for Ilford North. A report by Minister for Transport and Civil Aviation John Boyd-Carpenter stated that ventilation on the lower decks had been improved and that there would be greater variety in the menu offered. In June 1956, Empire Fowey was on a voyage from Singapore to Hong Kong when a passenger on board suffered a perforated duodenum. A surgeon and medical party were flown out the ship in a Royal Air Force Short Sunderland aircraft. They decided that an operation could not be carried out on board ship and she returned to Singapore to land the patient, who was taken to the Military Hospital for an emergency operation.
Empire Fowey was withdrawn from service in February 1960. She was put up for sale to "foreign or other buyers" in 1960, a decision criticised by Irene Ward, MP for Tynemouth. Initially chartered by the Pan-Islamic Steamship Co, Karachi, Pakistan. She was sold to them in 1960 and renamed Safina-E-Hujjaj. Used for transporting pilgrims to Jeddah, Saudi Arabia. With the introduction of IMO Numbers in the 1960s, she was allocated the number 5304891. She was in service until 20 February 1976. Safina-E-Hujjaj arrived at the Gadani ship-breaking yard on 22 November 1976 for scrapping.
References
1935 ships
Ships built in Hamburg
Steamships of Germany
Passenger ships of Germany
World War II merchant ships of Germany
Auxiliary ships of the Kriegsmarine
Proposed aircraft carriers
Empire ships
Ministry of War Transport ships
Passenger ships of the United Kingdom
Merchant ships of the United Kingdom
Steamships of the United Kingdom
Maritime incidents in 1955
Passenger ships of Pakistan
Steamships of Pakistan
Ships of Norddeutscher Lloyd | SS Empire Fowey | [
"Engineering"
] | 1,355 | [
"Military projects",
"Proposed aircraft carriers"
] |
53,104,418 | https://en.wikipedia.org/wiki/NGC%20411 | NGC 411 is a globular cluster located approximately from Earth in the constellation Tucana. It was discovered in 1826 by James Dunlop. It was described by Dreyer as "extremely faint, pretty large, round, gradually very little brighter middle". At a distance of about 180,000 light years (55,000 parsecs), it is located within the Small Magellanic Cloud. It has a mass of about , and a luminosity of about .
NGC 411 was imaged by the Hubble Space Telescope in 2013, showing an abundance of stars ranging from blue to red. In particular, this seemed to suggest that the cluster was much younger than previously thought: its age has been estimated at 1.5 billion years old, relatively young in astronomical terms. However, these results have been challenged by another group who state that these young stars may actually just be background stars, and are thus physically unrelated.
See also
List of NGC objects (1–1000)
References
External links
0411
Astronomical objects discovered in 1826
Tucana
Open clusters
Small Magellanic Cloud
Discoveries by James Dunlop | NGC 411 | [
"Astronomy"
] | 221 | [
"Tucana",
"Constellations"
] |
53,107,018 | https://en.wikipedia.org/wiki/Jerzy%20Luczak-Szewczyk | Jerzy Luczak-Szewczyk (2 January 1923, Lublin, Poland - 12 April 1975, Örebro, Sweden) was a Polish-born Swedish painter, drawer and sculptor.
Biography
Jerzy Luczak's birth name was Wojciech Stanisław Szewczyk. He was born in Lublin, Poland and lived there during his childhood together with his mother Wincentyna (maiden name: Skośkiewicz), his father Franciszek Szewczyk and his sister Janina. Already as a child he was interested in painting and when the family in the late 1920s moved to the outskirts of Warsaw, he became acquainted with an established artist who taught him different techniques. During his teens he began studies in art at schools in Warsaw. However, after the German invasion of Poland in September 1939, he had to end his education as German authorities took him to do forced labour in the spring of 1940.
The refugee
Luczak was sent to East Prussia, where he at first was commanded to work at a farm near the town Angerapp (present-day Ozyorsk, Kaliningrad Oblast) and later in a forced labour camp in Allenstein (Olsztyn). In the autumn of 1943 he escaped to Warsaw where a relative hid him. Since he was wanted by German authorities and lived under the threat of execution if he was found, he had to assume a new identity. Through contacts with the Polish Home Army (Polish: Armia Krajowa) he got false documents and the name Jerzy Luczak.
The false identity saved him from being executed when German military later took him again, during a round-up (Polish: Łapanka) in Warsaw. However he was sent to a forced labour camp, this time in Berlin, where he was forced to clear ruins after the Allied bombing raids. After some time he was selected together with about one hundred other prisoners to be sent to a forced labour camp in northern Norway. The group of prisoners was transported by boat via Stettin in Germany to Oslo in Norway. At the arrival Luczak escaped once more. He by coincidence met a man who contacted the Norwegian resistance movement. They helped him across the border to Sweden on the night between the 8 and 9 March 1944.
When Jerzy Luczak-Szewczyk arrived in Sweden, the immigration authorities sent him to Örebro (a town situated in the middle of the country) where he got a job in a photographers company. At the same time he began his career as a professional artist, but during the first years in Sweden he could not get documents from Poland to certify his true identity. Therefore, he used his false name Jerzy Luczak as his artist name. Even after he had been granted a Swedish citizenship under his real birth name in 1954, he continued to sign his works J. Luczak. It was not until the mid-1960s that he began to sign with both surnames. In 1950 Jerzy Luczak-Szewczyk married Swedish-born Inga Johansson in Örebro.
Career and exhibitions
Jerzy Luczak-Szewczyk worked mainly in oil painting, but he also used other media, such as drawing, stucco, sculpture and mosaic. Between his first Swedish exhibition in 1946 in Eskilstuna and his last in 1962 in Örebro, he had several exhibitions of his own and participated in group exhibitions. During the 1950s he also carried out decorations on public and private owned buildings, especially mural paintings and reliefs.
In the beginning of his career, Luczak's subjects were illustrations of his memories from the war, still lifes, portraits and landscapes. His paintings varied in quality, but he continued to work and to develop his skills. The paintings from the 1950s, especially his city scenes and landscapes, show that he gradually went from a style inspired by Cézanne, to an increasingly freer and personal way of expression.
Luczak's travels in Europe in the early 1960s, led to a radical change in his style. Instead of using brushes and palette knives, he started to paint with his hands on the canvas. Initially the subjects still were figurative compositions but from the middle of the decade he created surrealistic, expressive images of dramatic landscapes, populated by fantasy figures, fish and animals. The paintings were large, performed in a personal impasto technique and often in darkish colour tones.
During his travels in Europe Luczak visited museums and art galleries. He also introduced himself to gallery owners. An exhibition at the Galerie Bernheim-Jeune in Paris in 1965 led to positive reviews both in French and Swedish newspapers. This resulted in further exhibitions for example in Paris (Galerie Mouffe 1970), Biarritz (Galerie Vallombreuse 1970), New York (Galerie Internationale 1970) and in London (B. H. Corner Gallery 1971).
Jerzy Luczak-Szewczyk died 12 April 1975 in Örebro, Sweden. In 1970 he was appointed honorary member with silver medal of the Accademia Internazionale Tommaso Campanella in Rome. He is represented in Swedish private and public collections and in private collections in France, Belgium, the United Kingdom, the United States and Australia.
Notes
Additional literature
Bugatti, C. E. (1969) Guida all'arte Europea. Ancona, Italy: p. XXXIII and p. 83. (A dictionary of artists.)
Fourny, M. (1970) Annuaire de l'art international 1970-1971. Paris, France: p. 464. (A directory of artists and galleries.)
Lo Faro Editore, V. (1970) Traguardi dell'arte '70. Rome, Italy: vol. I, p. 284. (A dictionary of artists.)
Palmaer Waldén, M., Waldén K. (1965) Örebro i konsten. Örebro, Sweden. Drätselkammarens kansli. Unnumbered page.(The book concerns the town of Örebro as it has been presented in art.)
Rauschenbusch, H., ed. (1967,1969) International directory of arts. Berlin, Germany: Deutsche Zentraldrûckerei AG. 9th edition 1967: vol. 1, p. 745. 10th edition 1969: vol. 1, p. 824.
Selected Swedish newspaper articles and reviews of exhibitions
Ahlin, J. (16 October 2015) "Konstnär med spännande historia". Mariestads tidning. Mariestad, Sweden. (Article about five reliefs executed by the artist in 1956 in Mariestad.)
C.S. (16 April 1947) "Polsk målare ställer ut på Mollberg". Skånska Socialdemokraten. Hälsingborg, Sweden. (Review of one-man exhibition in Hälsingborg)
Fr. (16 November 1954) "Polsksvensk konstnär utställer i Bollnäs". Hälsinge-Kuriren. Bollnäs, Sweden. (Review of one-man exhibition in Bollnäs.)
G. H-d. (3 March 1948) "En polsk målare". Borås Tidning. Borås, Sweden (Review of one-man exhibition in Borås.)
G. (12 March 1949) "Polsk målare på Klostret". Arbetet. Malmö, Sweden. (Review of one-man exhibition in Lund.)
JoJo. (21 March 1955) "Intressant utställning i Säbysalen". Tranåsposten. Tranås, Sweden. (Review of one-man exhibition in Tranås.)
Lindén, G. (28 December 1965) "30.000 kronor gav fin utdelning". Nerikes Allehanda. Örebro, Sweden. (Article about the one-man exhibition in Paris 1965.)
Särnstedt, B. (9 November 1954) "Jersey Luczak". Östgöta Correspondenten. Linköping, Sweden. (Review of one-man exhibition in Motala.)
"Örebrokonstnär hemma igen efter lyckad amerikasejour Nu väntar London och Paris". (21 December 1970) Örebro Kuriren. Örebro, Sweden. (Article about the one-man exhibition in New York 1970.)
External links
Jerzy-Luczak-Szewczyk, Konstnärslexikonett Amanda, a dictionary of Swedish artists.
1923 births
1975 deaths
Artists from Lublin
Polish World War II forced labourers
Polish people imprisoned abroad
Escapees from German detention
Polish refugees
Refugees in Sweden
Polish emigrants to Sweden
Naturalized citizens of Sweden
Swedish still life painters
Swedish male sculptors
20th-century Swedish sculptors
Polish muralists
Swedish muralists
Plasterers
Draughtsmen
Mosaic artists
Swedish male painters
20th-century Swedish painters
Swedish landscape painters
Swedish portrait painters
20th-century Swedish male artists | Jerzy Luczak-Szewczyk | [
"Engineering"
] | 1,849 | [
"Design engineering",
"Draughtsmen"
] |
53,107,039 | https://en.wikipedia.org/wiki/Kotabe%20Foundry | Kotabe Foundry is a casting company established over 800 years ago and operated by the 37th successor to the family business.
It is located in Sakuragawa, Ibaraki Prefecture, Japan at the foot of the famous Mount Tsukuba, where sands and clay for the molds are found.
The main products are:
temple bells
fire bells
rainwater bowls etc.
See also
Early Japanese iron-working techniques
List of oldest companies
References
External links
Company website
Bells in Japanese temples
12th-century establishments in Japan
Foundries
Companies based in Ibaraki Prefecture
Metal companies of Japan | Kotabe Foundry | [
"Chemistry"
] | 114 | [
"Foundries",
"Metallurgical facilities"
] |
53,107,281 | https://en.wikipedia.org/wiki/Yang%20Shiming | Yang Shiming or Shih-Ming Yang () was a Chinese thermodynamicist, who was a pioneer in heat transfer in mainland China.
Yang was a standing member of the Executive Committee of the Chinese Society of Engineering Thermophysics and vice chairman of the National Educational Advisory Committee on Thermal Engineering. He had also served on the editorial board of the Journal of Engineering Thermophysics since 1980, the honorary editorial advisory board of the International Journal of Heat and Mass Transfer since 1982, and the executive committee as well as the Scientific Council of the International Centre of Heat and Mass Transfer since 1987.
Early life and education
Yang fled to Shanghai at age 12. The CPC influenced him when he was studying at a high school, and he joined the party in 1941.
Yang was enrolled at Shanghai Jiao Tong University in 1942. There was a hiatus in his undergraduate life, he backed to the university in 1946 and received his BS degree from there in 1948. Meantime, he successively served as a teacher at a technical school and an engineer at a rubber factory. Afterwards, he received his MS degree from Case Institute of Technology in 1950. Then he became a graduate student with Professor Max Jakob's guidance and obtained his Ph. D. degree from Illinois Institute of Technology in 1953.
Career
Upon the request of Jakob, Yang joined the Heat Transfer Laboratory of IIT before he returned to Shanghai at the end of 1953. Their concerted effort revealed the Jakob number.
Yang began to teach at Jiao Tong University since 1956, he followed the university's westward moving to Xi'an in the next year. During 1958–85, he was in charge of the thermal engineering section of Xi'an Jiaotong University as an associate professor and then a professor.
Bereavement of wife led to Yang's return to Shanghai Jiao Tong University, where he continued his work until retirement.
Yang made a great contribution to the Chinese thermodynamics education. The textbook Heat Transfer, which he edited, received the National Excellent Textbook Award in 1988.
Family
Yang's wife died in the 1980s. They had a daughter and a son.
References
1925 births
2017 deaths
National Chiao Tung University (Shanghai) alumni
Academic staff of Shanghai Jiao Tong University
Thermodynamicists
People from Wuxi | Yang Shiming | [
"Physics",
"Chemistry"
] | 470 | [
"Thermodynamics",
"Thermodynamicists"
] |
53,108,275 | https://en.wikipedia.org/wiki/Blue%20Prism | Blue Prism is the trading name of the Blue Prism Group plc, a British multinational software corporation that pioneered and makes enterprise robotic process automation (RPA) software that provides a digital workforce designed to automate complex, end-to-end operational activities. In March 2022, Blue Prism was acquired by SS&C Technologies.
Blue Prism's headquarters are at 2 Cinnamon Park Crab Lane Warrington WA2 0XP, UK with regional offices in the U.S. and Australia. The company was listed on the London Stock Exchange AIM market until its acquisition.
History
Formation
Blue Prism was founded in 2001. Initially their focus was on the back office where they recognised an enormous unfulfilled need for automation. The company was co-founded by Alastair Bathgate and David Moss to provide a new approach that today is known as robotic process automation, or RPA.
In 2003, Blue Prism's first commercial product, Automate, was launched. In 2005, the second version of Automate was released with features for large scale processing. Co-operative Financial Services began using Blue Prism software in 2005 to automate manual processes in customer services.
Robotic Process Automation
Robotic process automation (RPA) is the application of technology that provides organizations with a digital workforce that follows rule-based business processes and interacts with the organizations' systems in the same way that existing users currently do. Blue Prism has been credited for coining the term "Robotic Process Automation."
RPA is a growing industry and is expected to reach $3.11 billion by 2025. It has been used to handle the requests generated by the General Data Protection Regulation; by Tokio Marine Kiln for back-office transaction framework; by the nutrition company, Fonterra, to fix quantity mismatches in planning software SAP; and by Milaha for the entry, processing and transfer of data. The independent market research company Forrester Research identified Blue Prism as one of three companies that is considered a leader in the robotic process automation field both in terms of their market presence as well as the quality of their offering in a 2017 study.
An October 2018 study by Grand View Research, Inc. stated that the key companies in the RPA market included: Automation Anywhere, Inc.; Blue Prism Group PLC; UIPath; Be Informed B.V.; OpenSpan; and Jacada, Inc. In 2019, Gartner released its 'Magic Quadrant' for RPA, and Blue Prism was one of the leaders in the market.
Initial public offering
On 18 March 2016, Blue Prism undertook an IPO when the company floated on the London Stock Exchange AIM market with a market capitalisation of £48.5 million. The company's shares rose 44 percent on the first day of trading on AIM, under CEO Alastair Bathgate. Customers include O2, Co-operative Bank and Fidelity Investment Management. By November 2016, it had offices in Chicago and Miami, as well as the United Kingdom.
On 6 January 2017 Blue Prism announced it would open new offices in Austin, Texas, while remaining based in London. At the time, it employed 86 people worldwide. In March 2017, a group of shareholders sold stakes in Blue Prism. At the time, Blue Prism remained based in Merseyside. In June 2017, Blue Prism announced that a new version of its software would run on public clouds such as Amazon Web Services, Microsoft Azure, and Google Cloud Platform. Previously, the software had run on customers' own servers.
In 2019, Blue Prism announced changes to its platform and the issuing of new stock. It included a new AI engine, an updated marketplace for extensions, and a new lab for in-house AI innovation.
As of April 2020, the leadership team is made up of chairman and CEO Jason Kingdon and co-founder and CTO David Moss. Kingdon, an early investor in the company, became chairman in 2008 and led the company until its successful IPO in 2016. Kingdon returned as chairman in 2019 and became CEO in April 2020 when former CEO Alastair Bathgate stepped down, Kingdon remained CEO until 2022.
Acquisition
In September 2021, it was announced that Vista Equity Partners plans to acquire Blue Prism for £1.095 billion ($1.5 billion). Vista intends to merge Blue Prism into TIBCO Software. Vista is said to be considering "potentially material headcount reductions" of 8 to 10 per cent of the approximately 4,750 employees of the merged companies.
The original takeover deal was first announced in December 2021, when a bidding war between SS&C and Vista Equity partners drove up the price. Blue Prism shareholders ultimately voted in favor of SS&C. On 16 March 2022 SS&C Technologies announced it had completed its acquisition of Blue Prism for approximately $1.6 billion (£1.25 billion).
Blue Prism technology
Blue Prism is built on the Microsoft .NET Framework. It automates any application and supports any platform (mainframe, Windows, WPF, Java, web, etc.) presented in a variety of ways (terminal emulator, thick client, thin client, web browser, Citrix and web services). All of the process coding is automated on the back end, allowing even non-technical users to automate a process by dragging components into an interface.
In 2016, Blue Prism received one of the top honors at the AIconics Awards, named as The Best Enterprise Application of AI. In 2017, the company was named one of MIT Tech Review's 50 Smartest Companies and was the winner of the UK Tech Awards.
In 2019, Blue Prism announced its idea for connected-RPA. Connected-RPA is the offering of an automation platform with AI and cognitive features built in. It includes features like a Digital Exchange, with online access to drag and drop AI, machine learning, and cognitive and disruptive technologies; a web-based tool that reduces the time to prepare for a RPA deployment; and an online community for sharing knowledge and best practices. The Digital Exchange gives customers and partners the ability to create and share tools that can be used with Blue Prism's software. To encourage innovation, Blue Prism has an AI engine for building connectors to advanced AI tools from Amazon, Google, IBM, and other AI platforms.
In the summer of 2019, Blue Prism acquired Thoughtonomy for $100 million. Thoughtonomy was later renamed Blue Prism Cloud. The acquisition provided Blue Prism with Cloud capabilities, allowing them to offer Automation as a Service over the cloud.
Business and markets
Its RPA software has been purchased by companies such as Coca-Cola, Pfizer, Prudential, Sony, and Walgreens.
Blue Prism Ventures
In 2021, Blue Prism launched Blue Prism Ventures which helps venture partners find collaboration opportunities within the field of software robotic process automation. The company's first venture is in South Korea, Blue Prism Korea, with GTPlus Ltd.
References
External links
2001 establishments in England
Business software companies
Automation software
Artificial intelligence companies
British companies established in 2001
Software companies established in 2001
Companies based in Warrington
Software companies of England
Companies formerly listed on the Alternative Investment Market
2016 initial public offerings
2022 mergers and acquisitions
Science and technology in Cheshire | Blue Prism | [
"Engineering"
] | 1,462 | [
"Automation software",
"Automation"
] |
53,108,519 | https://en.wikipedia.org/wiki/Plant%20Information%20Management%20System | A Plant Information Management System (PIMS) collects and integrates information about a production process from different sources.
Overview
Tasks
Important tasks of a PIMS are:
Company-wide gather, consolidate and process data
Analysis of production performance, product quality, process capacity and control compliance.
Provide Key Performance Indicator (KPI) to improve decision-making processes
Reporting for decision support and documentation
Consolidation of data from different sources (Enterprise Resource Planning (ERP), Laboratory, Distributed Control System (DCS)...)
Integration of off-line data (laboratory, calculations, future load profiles)
Access via the company-wide intranet also from offices. Via Web (Thin client) or Tcp / Ip (Fat client)
Enriching / refining raw data
Event-driven calculations
Long-term archiving of data and reports (over many years)
Manufacturers
Manufacturers are:
Aspen Tech InfoPlus.21 (IP.21)
Elipse Software EPM - Elipse Plant Manager
GE Proficy Historian
Open Systems International Inc. CHRONUS™
Osisoft PI
Honeywell PHD
Wonderware Historian
Iba-ag Davis
Subdivisions
There are the following subdivisions:
SQL / desktop systems
SCADA Historian
Enterprise Historian
See also
Data acquisition
Data collection system
Totally integrated automation
References
Information systems
Industrial software | Plant Information Management System | [
"Technology"
] | 258 | [
"Industrial software",
"Information technology",
"Industrial computing",
"Information systems"
] |
53,109,212 | https://en.wikipedia.org/wiki/C%20Scorpii | The Bayer designation c Scorpii is shared by two star systems in the constellation Scorpius:
c1 Scorpii (12 Scorpii)
c2 Scorpii (13 Scorpii)
References
Scorpii, c
Scorpius | C Scorpii | [
"Astronomy"
] | 59 | [
"Scorpius",
"Constellations"
] |
53,109,824 | https://en.wikipedia.org/wiki/IT%20process%20automation | IT process automation (ITPA) is a series of processes which facilitate the orchestration and integration of tools, people and processes through automated workflows. ITPA software applications can be programmed to perform any repeatable pattern, task or business workflow that was once handled manually by humans.
Description
ITPA is often used interchangeably with the term run book automation (RBA).
IT departments in organizations of every size and industry can employ ITPA technology to specify certain criteria and outcomes for almost any task or process currently being performed. When a system event occurs, the appropriate workflow is triggered and executed to automatically address and remediate the problem. This is often seen in IT service management or ESM during the ticketing process, it is becoming much more commonplace in daily business functions.
Advanced ITPA software is intuitive enough to automate complex processes across multiple systems with or without the need for human input. When desired or necessary, human decision points can also be embedded into the workflow ensuring that the appropriate IT personnel receive alerts and/or escalations and can quickly respond accordingly.
Some ITPA software products can be fully and seamlessly integrated with various existing systems, applications and platforms. This may include monitoring, incident response, messaging and notification and much more.
Applications
The purpose of IT process automation is to streamline IT operations in a number of areas and facets. It is used to replace repetitive manual tasks, processes and workflows with automated solutions. The ITPA product can be versatile enough to bridge multiple systems, applications and platforms to create a more uniform IT infrastructure.
Each task is designed as a workflow which contains specified procedures, conditions and triggers. Automated workflows can be scheduled in advance, or designed to be triggered based on specific events or conditions. For instance, an automated workflow to perform routine system maintenance tasks could be scheduled to execute automatically at a designated time each day or week.
Another automated process might be triggered, based on a particular event, such as a stoppage of service or system outage. Based on predetermined control flows, the ITPA tool can automatically remediate the problem or send alerts/escalations to the appropriate human decision-maker for immediate action.
Results
Businesses employing IT process automation may experience a number of consequences including:
Cost savings
Increased productivity
Greater efficiency
Reduction in errors
Faster response to system problems
Improved service levels
Job losses
Related Concepts
robotic process automation (RPA)
workload automation
ITSM automation
NOC automation
SOC automation
SIEM automation
Self-service automation
payroll automation
References
Information technology management | IT process automation | [
"Technology"
] | 519 | [
"Information technology",
"Information technology management"
] |
64,310,512 | https://en.wikipedia.org/wiki/Bharat%20Ki%20Chhap | Bharat Ki Chhap (Identity of India) is a 13-episode Indian TV science documentary series chronicling the history of science and technology in India from pre-historic times until the present. It was directed by filmmaker Chandita Mukherjee and funded by the Department of Science and Technology's National Council for Science and Technology Communication (NCSTC) in 1987. It was telecasted on Doordarshan every Sunday Morning. It was introduced by Professor Yash Pal.
It projected in a pragmatic way alternative viewpoints on the subject of science as pioneered in India, in contrast with western scientific endeavours. It drew support from People's Science Movement.
A companion book was later published by Comet Project titled Bhārat Ki Chhāp: A Companion Book to the Film Series by Chayanika Shah, Suhas Paranjape, Swatija Manorama.
Episodes
A total of 13 episodes were released.
References
Documentary films about the history of science
History of science
Hindi-language television shows
Indian documentary television series
DD National original programming
1987 Indian television series debuts | Bharat Ki Chhap | [
"Technology"
] | 217 | [
"History of science",
"History of science and technology"
] |
64,313,176 | https://en.wikipedia.org/wiki/Man%20and%20the%20Planets | Man and the Planets: The Resources of the Solar System is a book written by Duncan Lunan.
Contents
Man and the Planets is a book published in 1983 which studies the resources of each planet in the Solar System.
Reception
Dave Langford reviewed Man and the Planets for White Dwarf #41, and stated that "Lunan's enthusiasm is infectious, his research exhaustive; he's absolutely committed to the Dream of Space and has no time for the many equally learned people who fear that the expense of opening up this new frontier would wreck our world economy long before producing tangible benefits."
Reviews
Review by Tom Easton (1983) in Analog Science Fiction/Science Fact, November 1983
Space Voyager
References
Astronomy books | Man and the Planets | [
"Astronomy"
] | 143 | [
"Astronomy books",
"Works about astronomy"
] |
64,314,552 | https://en.wikipedia.org/wiki/Floriana%20Tuna | Floriana Tuna is a Romanian chemist and a Senior Research Fellow in the Department of Chemistry at The University of Manchester. Her research in general is based on inorganic chemistry and magnetochemistry, specifically on molecular magnetism, EPR spectroscopy and quantum computing.
Education
Floriana completed her Bachelor of Science at University of Bucharest. She continued to read her Master of Science degree at University of Bucharest and successfully completed it in 1989 before moving to the Institute of Physical Chemistry of the Romanian Academy to read her Doctor of Philosophy degree in transition metal chemistry, which was completed in 1997 and was supervised by Marius Andruh and Luminița Patron.
Research and career
Upon graduation, Floriana completed her postdoctoral research in Molecular Magnetism with Jean-Pascal Sutter at Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), France and also as a visiting Deutscher Akademischer Austauschdienst (DAAD) Fellow at University of Heidelberg, Germany. She then received a Marie Curie Individual Fellowship at University of Warwick to work in supramolecular chemistry before moving to University of Manchester in 2003 as a Researcher. She was later promoted to the position of Senior Researcher. She is currently part of the Molecular Magnetism group at University of Manchester, working along with David Collison, Nicholas F. Chilton, Grigore Timco, and Richard Winpenny.
Floriana's research in general is based on inorganic chemistry and magnetochemistry, specifically on molecular magnetism, EPR spectroscopy and quantum computing.
Notable work
In 2019, Floriana participated in a research which reported the capability of a MFI-type zeolite (NbAlS-1) could be used to convert aqueous solutions of γ-valerolactone (GVL) (obtained from biomass-derived carbohydrates) into butenes with a yield of more than 99% at ambient pressure under continuous flow conditions. The conversion of the renewable biomass into butenes offered the prospect for the sustainable production of butene as a platform chemical for the manufacture of renewable materials.
In 2019, she participated in a research which showed the capability to use a porous metal–organic framework (MOF) to provide a selective, fully reversible and repeatable capability to capture nitrogen dioxide (NO2), a toxic air pollutant produced particularly by diesel and bio-fuel use. The NO2 can then be easily converted into nitric acid, an industry with a wide range of uses including, agricultural fertilizer for crops; rocket propellant and nylon.
In 2016, Floriana confirmed the capability to use pulsed EPR spectroscopy to measure the covalency of actinide complexes in a research in collaboration with Eric McInnes and David P. Mills at the University of Manchester. Prior to this research, the extent of covalency in actinide complexes was less understood as this nature of bonding was not studied due to limited technology and methods of experimentation at the time. The use of pulsed EPR spectroscopy was able to determine the covalency of thorium(III) and Uranium(III) complexes for the first time and this paved the way to further research on the use of these complexes in the separation and recycling of nuclear waste.
Awards and nominations
Romanian Academy 'Ilie Murgulescu' Award (2005)
Major publications
References
External links
Floriana Tuna at University of Manchester
Living people
Year of birth missing (living people)
21st-century chemists
Academics of the University of Manchester
University of Bucharest alumni
Inorganic chemists
Romanian chemists
Romanian women scientists
Romanian emigrants to the United Kingdom
Romanian expatriates in England | Floriana Tuna | [
"Chemistry"
] | 744 | [
"Inorganic chemists"
] |
64,315,181 | https://en.wikipedia.org/wiki/Vladimir%20Anikeyev | Vladimir Fedorovich Anikeyev () is the former ringleader of the anonymous group Shaltai Boltai. He was detained in Russia in November 2016, and was later sentenced to two years in prison for unlawful access to computer information.
Early career
Anikeyev worked in the St. Petersburg media during the 1990s. He reportedly was not regarded as a great writer, but he was able to acquire many contacts in the Russian government.
At a party in Russia around 2004, Anikeyev had reportedly met Alexander Glazastikov and Konstantin Teplyakov, two future members of Shaltai Boltai.
In 2013, Anikeyev proposed the idea of occasionally publishing political materials that might be of interest to the public. Glazastikov concurred. The two would later discuss who would be called Shaltai and who would be called Boltai when communicating with reporters.
Shaltai Boltai
At the end of 2013, Shaltai Boltai gained instant fame in Russia when a leaked transcript of the speech that Vladimir Putin was planning to give on New Year's Eve was published on their blog.
The following year, communications from high-profile figures like Arkady Dvorkovich and Yevgeny Prigozhin were published, culminating in the Shaltai Boltai blog being blocked by Russia authorities.
In the summer of 2014, Anikeyev was reportedly approached by an intermediary of a potential client who was interested in acquiring the identities of members of Shaltai Boltai.
By early 2016, due to concerns that Russian intelligence services would soon be able to identify Anikeyev's source network, operations at Shaltai Boltai were reportedly halted.
FSB influence
Teplyakov claims that Anikeyev was recruited by the FSB in August 2015.
Other reports say Anikeyev's cooperation with the FSB, specifically Sergei Mikhailov (FSB) and Dmitry Dokuchaev, began sometime in 2016.
Anikeyev himself has denied these reports.
Arrest
In October 2016, Anikeyev was reportedly lured away from Kyiv and towards the border of Belarus, where he was detained and then transported to Russia.
In January 2017, Anikeyev pleaded guilty to unlawful access to computer information.
His arrest was first announced on January 28, 2017.
Conviction
In July 2017, Anikeyev was sentenced to two years in prison.
He was released in August 2018.
References
Hackers
1974 births
Living people
Russian cybercriminals | Vladimir Anikeyev | [
"Technology"
] | 504 | [
"Lists of people in STEM fields",
"Hackers"
] |
64,315,976 | https://en.wikipedia.org/wiki/It%20Takes%20Two%20%28video%20game%29 | It Takes Two is a 2021 cooperative action-adventure game developed by Hazelight Studios and published by Electronic Arts. The game was released for PlayStation 4, PlayStation 5, Windows, Xbox One, and Xbox Series X/S in March 2021, and was released for Nintendo Switch in November 2022.
Like Hazelight's debut game A Way Out, It Takes Two does not have a single-player option. It is playable only in either online or local split screen cooperative multiplayer between two players. The game follows a couple transformed into living dolls as they attempt to find a way out while trying to mend their relationship.
It Takes Two received positive reviews from critics and won multiple year-end accolades, including Game of the Year at The Game Awards 2021 and the 25th Annual D.I.C.E. Awards. The game had sold over 20 million units by October 2024.
Gameplay
It Takes Two is an action-adventure video game with elements from platform games. It is specifically designed for split-screen cooperative multiplayer, which means that it must be played with another player through either local or online play. The game features a large number of game mechanics from various video game genres. These gameplay mechanics are connected to the story and the theme of the level. For instance, in one level, Cody gains the ability to rewind time, whereas May can replicate herself. Players have to cooperate with each other and utilize these abilities in order to progress. The game also features a large number of minigames.
Plot
Cody (Joseph Balderrama) and May (Annabelle Dowler), a married couple, are planning on getting a divorce. After they tell their daughter Rose (Clare Corbett) the news, she takes her hand-made dolls, which look like her parents, into the family shed and tries to repair their relationship by play-acting. The parents find themselves trapped inside the dolls' bodies as a consequence of Rose's tears landing on the dolls. Dr. Hakim, who has assumed the anthropomorphic form of his relationship therapy book, tells May and Cody that he has been given the job of trying to fix their relationship as they try to reach Rose.
At first, Cody and May are more focused on trying to reach Rose, who they hope knows of a way to return them to their human bodies. However, Hakim continually interferes with their progress, often putting obstacles and tests in their way to force them to collaborate to progress. They also come across anthropomorphic versions of their old possessions, who criticize Cody and May for their mistreatment and negligence of both their possessions and Rose. As they travel all around their property, Cody and May are reminded of the positive memories they had together, as well as what originally drew them together to become a couple, and learn to work together and collaborate to move forward in their journey.
In a final series of obstacles, Hakim encourages Cody and May to rediscover their passions and support each other. This first takes them on an adventure through Cody's overgrown, abandoned garden and greenhouse, which May helps him to restore. They then work together to help May rediscover her passion for music and singing.
Meanwhile, Rose continues to do her best to mend the relationship between her parents, but both Cody and May's real bodies have fallen unconscious and will not respond to her. Thinking her parents are ignoring her, Rose comes to believe that she is the reason their marriage is falling apart and decides to run away in hopes that will make them stay together.
After a long journey, Cody and May finally complete Hakim's final test, gathering an orchestra and audience for May to perform in front of. As May sings, the relationship between her and Cody is at last fully healed, and they kiss, which reverses the trance they are in. They reawaken in their real bodies and are shocked to learn that Rose has already run away. Fortunately, they are able to find her at a nearby bus stop and assure her that she is not the cause of their arguments and that they will always love her no matter what happens. The trio then return home with a new perspective on their relationship.
Development and release
Josef Fares, the director of Hazelight's previous game A Way Out (2018) and Starbreeze's Brothers: A Tale of Two Sons (2013), returned and directed a team of 60 people to develop the game. After releasing A Way Out in 2018, the team decided to create another co-op only video game because it had a more experienced and refined team and the team felt that they could further improve and expand the gameplay concepts introduced by A Way Out. The development team worked to ensure that the gameplay had connection with the narrative, and that as the story unfolds, the game's mechanics will change accordingly. Fares pushed his team to include as many mechanics and setpieces as possible since he believed that if a gameplay mechanic is used repeatedly, it will become "less special". Fares described the game as a "romantic comedy". Fares provided motion capture for Dr. Hakim, one of the key characters in the game. The game was written mostly in AngelScript, which was implemented into the Unreal Engine by Hazelight through their own plugin.
Like A Way Out, It Takes Two was published under Electronic Arts' EA Originals program. The program allowed Hazelight to retain full creative control while receiving most of the game's profit after development cost was recouped. EA signed a publishing deal with Hazelight in June 2019. The game was officially revealed during EA Play in June 2020. EA and Hazelight introduced Friend's Pass for the game, which allows the player who purchased the game to send invitations to their friends who can then play the game for free with the player. The game was released for PlayStation 4, PlayStation 5, Windows, Xbox One and Xbox Series X/S on March 26, 2021. A port by Turn Me Up Games for the Nintendo Switch was released on 4 November 4, 2022.
Trademark complaint
After the game was released, Hazelight Studios attempted to file a trademark for the name It Takes Two, but Take-Two Interactive filed a trademark complaint, arguing it was too close to their trademark on the words "take" and "two". Hazelight abandoned the trademark application of the name, making it difficult for them to engage in certain types of marketing, but the developers said they are "hopeful it will be resolved".
Reception
Critical reception
It Takes Two received "generally favorable" reviews from critics, according to review aggregator website Metacritic. It Takes Two was considered as one of the best games released in 2021 and the best couch co-op game of that year by many fans.
Sales
It Takes Two sold over 1 million units in a month after the game's launch. By June 2021, the game had sold over 2 million units and by October, had sold 3 million units. By February 2022, it had sold 5 million units and by July, 7 million units were sold. By February 2023, over 10 million units were sold. By March 2024, over 16 million units have been sold. By October, it had sold over 20 million units.
Accolades
Adaptations
As of January 2022, two adaptations, a feature film and a television series, were in development from Dmitri M. Johnson's dj2 Entertainment studios.
Film
A feature length film was officially in development beginning in January 2022, with Pat Casey and Josh Miller slated to be working on the screenplay for the film, while a multi-studio bidding war for distribution rights was ongoing. The project will include collaborative input from the video game's creative developer, Hazelight Studios. By April, Amazon acquired distribution rights, as part of a first-look deal between the company, dj2 Entertainment, and the screenwriters. The plot was confirmed to follow the basic premise of the game: lead characters May and Cody are a married couple considering divorce whose minds are inadvertently trapped in two dolls when their daughter starts crying. Together the couple must learn to work together, and regain their bodies. Dwayne Johnson, Dany Garcia, and Hiram Garcia joined the production in producing roles, alongside Dmitri M. Johnson and Dan Jevons. The project will be a joint-venture production between Hazelight Studios, dj2 Entertainment, Seven Bucks Productions, and Amazon MGM Studios. Intended to be released via streaming as a Prime Video Original Film, Johnson is also being courted to star in the film.
Notes
References
External links
2021 video games
3D platformers
Action-adventure games
Asymmetrical multiplayer video games
British Academy Games Award for Multiplayer winners
Electronic Arts games
Golden Joystick Award winners
Indie games
Multiplayer video games
Nintendo Switch games
Platformers
PlayStation 4 games
PlayStation 4 Pro enhanced games
PlayStation 5 games
Split-screen multiplayer games
The Game Award for Game of the Year winners
Unreal Engine 4 games
Video games about magic
Video games about size change
Video games about toys
Video games developed in Sweden
Video games featuring female protagonists
Video games scored by Gustaf Grefberg
Windows games
Works about divorce
Xbox One games
Xbox One X enhanced games
Xbox Series X and Series S games
Hazelight Studios games
Cooperative video games | It Takes Two (video game) | [
"Physics"
] | 1,861 | [
"Asymmetrical multiplayer video games",
"Symmetry",
"Asymmetry"
] |
64,317,471 | https://en.wikipedia.org/wiki/Taeuber%20Paradox | The Taeuber Paradox is a paradox in demography, which results from two seemingly contradictory expectations given a population-wide decrease in mortality, e.g. from curing or reducing the mortality of a disease in a population. The two expectations are:
Since the disease would have otherwise caused some deaths, there should be fewer deaths if the disease is cured than in the world where the disease is not cured
Since everyone dies eventually, there must in the long run be the same number of deaths, and the deaths will be redistributed among the remaining causes.
The paradox was named after Conrad Taeuber (1906-99), a sociologist and demographer.
Resolution
The paradox is resolved by noting that the life expectancy of the population will increase when the disease is cured, leading to a temporary decrease in the overall death rate before deaths are reapportioned among other causes. Thus, curing a disease will not cause an overall decrease in population mortality, but can improve mortality in certain groups (e.g. at certain ages) within a population, or even across all groups (e.g. all ages) within the populations. Comparing two populations with the same overall mortality while one has lower mortality in each subgroup is an example of Simpson's paradox.
Estimation
In the special case where the force of mortality is reduced by a constant fraction X, then the increase in life expectancy can be estimated as X * H * e, where e is the life expectancy before the reduction in mortality and H is estimated as (2 - e / a), where a is the stationary age of the population. As an example, if cancer is responsible for 10% of all deaths at all ages and were suddenly cured, in a population with an expected lifespan of 75 years and an average age of 50 (giving an estimated H of 1/2), we would estimate life expectancy to increase by only 3.75 years (5% of the original life expectancy, rather than the larger 10% increase you might expect intuitively).
As of 2005, H was estimated to be around 0.2 and 0.15 for men and women respectively in European and American countries with life expectancy of around 70, a significant decrease from estimates of 0.3 to 0.4 from 30 years earlier, which indicates that now more people live to near their life expectancy, and that a decrease in mortality would now result in a smaller increase in life expectancy.
Based on US government estimates using 1989 life table data, eliminating death from all malignant neoplasms would increase US life expectancy at birth by 3.36 years, while eliminating deaths from all major cardiovascular diseases would increase life expectancy at birth by 6.73 years.
See also
Sullivan's Index
References
External links
Average Life Expectancy In UK
Paradoxes
Demography
Life expectancy | Taeuber Paradox | [
"Biology",
"Environmental_science"
] | 577 | [
"Senescence",
"Life expectancy",
"Demography",
"Environmental social science"
] |
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