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57,226,844 | https://en.wikipedia.org/wiki/Allied%20Communications%20Publications | Allied Communications Publications are documents developed by the Combined Communications-Electronics Board and NATO, which define the procedures for communicating in computer messaging, radiotelephony, radiotelegraph, radioteletype (RATT), air-to-ground signalling (panel signalling), and other forms of communications used by the armed forces of the five CCEB member countries and/or NATO.
See also
Allied Communication Procedures
References
Military communications
Military standardization | Allied Communications Publications | Engineering | 90 |
25,482,873 | https://en.wikipedia.org/wiki/SkyGrabber | SkyGrabber is a software from the Russian company SkySoftware which accepts input from a digital satellite tuner card for hard drive recording.
History
It was used by Iraqi insurgents from the group Kata'ib Hezbollah to intercept MQ-1 Predator drone video feeds, which were not encrypted. The encryption for the feeds was removed for performance reasons.
See also
Comparison of packet analyzers
Satellite Internet access
References
Computer surveillance
Network analyzers | SkyGrabber | Technology | 91 |
71,750,784 | https://en.wikipedia.org/wiki/W0410-0913 | W0410-0913 is a hyper-luminous galaxy and an early universe star forming galaxy that is around 12 billion light years (ly) from Earth. W0410-0913 has a swarm of 24 galaxies close to the W0410-0913 galaxy that may activate a quasar. Due to this, it is one of the most massive, brightest and gas rich galaxy in the early universe.
References
Luminous infrared galaxies
Eridanus (constellation) | W0410-0913 | Astronomy | 100 |
2,925,061 | https://en.wikipedia.org/wiki/SOLEIL | SOLEIL ("Sun" in French) is a synchrotron facility near Paris, France. It performed its first acceleration of electrons on May 14, 2006. The name SOLEIL is a backronym for Source Optimisée de Lumière d’Énergie Intermédiaire du LURE (LURE optimised intermediary energy light source), LURE meaning Laboratoire pour l'Utilisation du Rayonnement Électromagnétique.
The facility is run by a civil corporation held by the French National Centre for Scientific Research (CNRS) and the French Alternative Energies and Atomic Energy Commission (CEA), two French national research agencies. It is located in Saint-Aubin in the Essonne département, a south-western suburb of Paris, near Gif-sur-Yvette and Saclay, which host other facilities for nuclear and particle physics.
The facility is an associate member of the University of Paris-Saclay.
SOLEIL also hosts IPANEMA, the European research platform on ancient materials (archaeology, palaeontology, past environments and cultural heritage), a joint CNRS / French Ministry of Culture and Communication research unit.
SOLEIL covers fundamental research needs in physics, chemistry, material sciences, life sciences (notably in the crystallography of biological macromolecules), earth sciences, and atmospheric sciences. It offers the use of a wide range of spectroscopic methods from infrared to X-rays, and structural methods such as X-ray diffraction and scattering.
Main parameters
SOLEIL contains electrons travelling with an energy of 2.75 GeV around a 354 m circumference. It takes the electrons 1.2 μs to travel around this ring at almost the speed of light; 847,000 times per second.
Most Cited Scientists at Synchrotron SOLEIL
According to Google Scholar, in 2024 this is the top 10 of most cited scientists of Synchrotron Soleil:
John Bozek
Citations: 23,755
Research Areas: X-ray physics, synchrotron radiation, XFEL, chemical physics, ultrafast X-ray
Jose Avila
Citations: 15,273
Research Areas: Not specified
Amina Taleb Ibrahimi
Citations: 12,628
Research Areas: Condensed matter physics, low-dimensional systems
Timm Weitkamp
Citations: 11,773
Research Areas: X-ray imaging, microtomography, X-ray microscopy, X-ray phase contrast imaging
Laurent Nahon
Citations: 10,754
Research Areas: Chirality, circular dichroism, molecular photoionization, VUV spectroscopy, polarimetry
Andrea Zitolo
Citations: 8,535
Research Areas: Physical chemistry, Material sciences, materials for energy and hydrogen
Patrick Le Fèvre
Citations: 8,187
Research Areas: Physics
François Bertran
Citations: 7,977
Research Areas: Physics
Pavel Dudin
Citations: 7,775
Research Areas: Band structure, materials science, topological insulators, graphene, superconductors
Pierre Legrand
Citations: 7,706
Research Areas: Structural virology, nucleic acid-protein interaction, crystallography, tomography, synchrotron
References
External links
Official website
Official website
LURE website
Lightsources.org
Official website of IPANEMA
Official website of IPANEMA
Synchrotron radiation facilities
Research institutes in France | SOLEIL | Physics,Materials_science | 696 |
21,060,764 | https://en.wikipedia.org/wiki/Pyrotechnic%20heat%20source | A pyrotechnic heat source, also called heat pellet, is a pyrotechnic device based on a pyrotechnic composition with a suitable igniter. Its role is to produce controlled amount of heat. Pyrotechnic heat sources are usually based on thermite-like (or sometimes delay composition-like) fuel-oxidizer compositions with slow burn rate, high production of heat at desired temperature, and low to zero production of gases.
Pyrotechnic heat sources can be activated by multiple means. Electric match and percussion cap are the most common ones.
Pyrotechnic heat sources are often used for activation of thermal batteries, where they serve to melt the electrolyte. There are two main types of design. One uses a fuze strip (containing barium chromate and powdered zirconium metal in a ceramic paper) along the edge of the heat pellets to initiate burning. The fuze strip is typically fired by an electrical igniter or squib by application of electric current. The second design uses a center hole in the battery stack into which the high-energy electrical igniter fires a mixture of hot gases and incandescent particles. The center-hole design allows much faster activation times (tens of milliseconds) vs. hundreds of milliseconds for the edge-strip design. Battery activation can also be accomplished by a percussion primer, similar to a shotgun shell. It is desired that the pyrotechnic source be gasless. The standard heat source typically consist of mixtures of iron powder and potassium perchlorate in weight ratios of typically 88/12, 86/14, and 84/16. The higher the potassium perchlorate level, the higher the heat output (nominally 200, 259, and 297 calories/gram, respectively). The size and thickness of the iron-perchlorate pellets has little influence on their burn rate, however the effect of density, composition, and particle size have significant effect on the burn rate and can be used for its adjusting for desired heat output profile. Another composition in use is zirconium with barium chromate. Another mixture is 46.67 wt.% of titanium, 23.33% of amorphous boron, and about 30% barium chromate. Yet another one is 45 wt.% tungsten, 40.5% barium chromate, 14.5% potassium perchlorate, and 1% vinyl alcohol acetate resin binder.
Reactions producing intermetallic components, e.g. zirconium with boron, can be used when entirely gasless operation, non-hygroscopic behavior, and independence on environmental pressure are desired.
Heat paper can be prepared by impregnating paper or a fiberglass tape with a slurry of the mixture of fuel and oxidizer.
A pyrotechnic heat source can be a direct part of a pyrotechnic composition e.g. in chemical oxygen generators a heat source composition with large surplus of oxidizer is used; the heat produced by burning the composition is used for thermal decomposition of the oxidizer. Relatively cold-burning compositions are used for production of colored smoke or for dispersion of aerosol of e.g. pesticides or CS gas, providing the heat of sublimation of the desired compound.
A phase moderating component of the composition, which forms together with the combustion products a mixture with at least one distinct temperature of phase transition, may be used for stabilizing the burning temperature as a form of phase-change material.
References
Pyrotechnic compositions | Pyrotechnic heat source | Chemistry | 764 |
11,436,523 | https://en.wikipedia.org/wiki/Cercospora%20platanicola | Cercospora platanicola is a fungal plant pathogen. It causes leaf spot on the plane-tree.
During early spring, Cercospora spores are produced in the fruiting bodies of infected leaves. It appears as uneven, round tan spots with red and brown haloes that are approximately 0.1 to 1cm large. Infections of Cercospora are of minor consequence to a tree's health, but may be treated with organic pesticides in the case of a severe outbreak.
See also
List of Cercospora species
References
platanicola
Fungal plant pathogens and diseases
Fungus species | Cercospora platanicola | Biology | 124 |
22,826,856 | https://en.wikipedia.org/wiki/Kinase%20tyrosine-based%20inhibitory%20motif | The term Kinase tyrosine-based inhibitory motif (KTIM) was coined by a group of immunology researchers from McGill University, Montreal, Quebec, Canada in 2008 to represent any immunoreceptor tyrosine-based inhibitory-like sequence motif, with the consensus sequence I/V/L/SxYxxL/V, found in a kinase and regulating its activity.
One major way in which cells respond to stimuli is through signal transduction pathways, whereby a ligand binds to a receptor, causing conformational changes that lead to a cascade of events in intracellular signalling molecules. This ultimately ends up in the translocation of transcription factors to the nucleus altering the expression of target genes, therefore affecting specific cellular functions. One way activation signals can be counteracted is through the triggering of different receptors bearing immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in their cytoplasmic tails.
Several transmembrane receptors are negatively regulated through recruiting cytosolic SH2 domain-containing proteins such as SHP-1 to immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that they possess. ITIM-like motifs (KTIMs) were shown to exist in non-receptor proteins and to play a key role in their regulation.
Difference between KTIM and ITIM
The main difference between ITIM and KTIM is that KTIM was shown to be found in a cytosolic protein (IL-1 receptor-associated Kinase 1 (IRAK-1)) and not in a transmembrane protein such as the case with ITIMs.
KTIM function
KTIMs are speculated to play a regulatory role in the negative regulation of many kinases in addition to IRAK-1, and can thus represent a novel regulatory mechanism in a wide range of cellular kinases. The mode of action of KTIMs is similar to ITIMs and involves recruiting SH2 domain-containing proteins such as SHP-1.
References
Immunology | Kinase tyrosine-based inhibitory motif | Biology | 428 |
11,128,508 | https://en.wikipedia.org/wiki/Rhizopus%20circinans | Rhizopus circinans is a plant pathogen infecting almond, apricot and peach.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Stone fruit tree diseases
Mucoraceae
Fungus species | Rhizopus circinans | Biology | 52 |
550,701 | https://en.wikipedia.org/wiki/Prime%20geodesic | In mathematics, a prime geodesic on a hyperbolic surface is a primitive closed geodesic, i.e. a geodesic which is a closed curve that traces out its image exactly once. Such geodesics are called prime geodesics because, among other things, they obey an asymptotic distribution law similar to the prime number theorem.
Technical background
We briefly present some facts from hyperbolic geometry which are helpful in understanding prime geodesics.
Hyperbolic isometries
Consider the Poincaré half-plane model H of 2-dimensional hyperbolic geometry. Given a Fuchsian group, that is, a discrete subgroup Γ of PSL(2, R), Γ acts on H via linear fractional transformation. Each element of PSL(2, R) in fact defines an isometry of H, so Γ is a group of isometries of H.
There are then 3 types of transformation: hyperbolic, elliptic, and parabolic. (The loxodromic transformations are not present because we are working with real numbers.) Then an element γ of Γ has 2 distinct real fixed points if and only if γ is hyperbolic. See Classification of isometries and Fixed points of isometries for more details.
Closed geodesics
Now consider the quotient surface M=Γ\H. The following description refers to the upper half-plane model of the hyperbolic plane. This is a hyperbolic surface, in fact, a Riemann surface. Each hyperbolic element h of Γ determines a closed geodesic of Γ\H: first, by connecting the geodesic semicircle joining the fixed points of h, we get a geodesic on H called the axis of h, and by projecting this geodesic to M, we get a geodesic on Γ\H.
This geodesic is closed because 2 points which are in the same orbit under the action of Γ project to the same point on the quotient, by definition.
It can be shown that this gives a 1-1 correspondence between closed geodesics on Γ\H and hyperbolic conjugacy classes in Γ. The prime geodesics are then those geodesics that trace out their image exactly once — algebraically, they correspond to primitive hyperbolic conjugacy classes, that is, conjugacy classes {γ} such that γ cannot be written as a nontrivial power of another element of Γ.
Applications of prime geodesics
The importance of prime geodesics comes from their relationship to other branches of mathematics, especially dynamical systems, ergodic theory, and number theory, as well as Riemann surfaces themselves. These applications often overlap among several different research fields.
Dynamical systems and ergodic theory
In dynamical systems, the closed geodesics represent the periodic orbits of the geodesic flow.
Number theory
In number theory, various "prime geodesic theorems" have been proved which are very similar in spirit to the prime number theorem. To be specific, we let π(x) denote the number of closed geodesics whose norm (a function related to length) is less than or equal to x; then π(x) ~ x/ln(x). This result is usually credited to Atle Selberg. In his 1970 Ph.D. thesis, Grigory Margulis proved a similar result for surfaces of variable negative curvature, while in his 1980 Ph.D. thesis, Peter Sarnak proved an analogue of Chebotarev's density theorem.
There are other similarities to number theory — error estimates are improved upon, in much the same way that error estimates of the prime number theorem are improved upon. Also, there is a Selberg zeta function which is formally similar to the usual Riemann zeta function and shares many of its properties.
Algebraically, prime geodesics can be lifted to higher surfaces in much the same way that prime ideals in the ring of integers of a number field can be split (factored) in a Galois extension. See Covering map and Splitting of prime ideals in Galois extensions for more details.
Riemann surface theory
Closed geodesics have been used to study Riemann surfaces; indeed, one of Riemann's original definitions of the genus of a surface was in terms of simple closed curves. Closed geodesics have been instrumental in studying the eigenvalues of Laplacian operators, arithmetic Fuchsian groups, and Teichmüller spaces.
See also
Fuchsian group
Modular group Gamma
Riemann surface
Fuchsian model
Analytic number theory
Zoll surface
Riemann surfaces
Differential geometry
Dynamical systems
Number theory
Geodesic (mathematics)
Hyperbolic geometry | Prime geodesic | Physics,Mathematics | 967 |
10,835,002 | https://en.wikipedia.org/wiki/NGC%206752 | NGC 6752 (also known as Caldwell 93 and nicknamed the Great Peacock Globular) is a globular cluster in the constellation Pavo. It is the fourth-brightest globular cluster in the sky, after Omega Centauri, 47 Tucanae and Messier 22, respectively. It is best seen from June to October in the Southern Hemisphere. It is also known as NGC 6777, though this identification is uncertain.
NGC 6752 was first identified by one James Dunlop of Parramatta on 30 June 1826, who described it as an irregular bright nebula which could be resolved into a cluster of many stars, highly compressed at the centre. This corresponds with a core region densely populated with stars around 1.3 light-years in diameter, which indicates it has undergone core collapse. The cluster lies around 13,000 light-years distant and is one of the closer globular clusters to Earth. It also lies 17,000 light-years away from the galactic centre. It belongs to Shapley–Sawyer Concentration Class VI, namely of intermediate density, and has been calculated to be 11.78 billion years old. There are many binary stars in the system, as well as blue stragglers, which are likely to have been formed by collisions and mergers of smaller stars.
The apparent magnitude of the cluster is 5.4, so it can be seen with the unaided eye. However this depends on good viewing conditions with a minimum of light pollution. With binoculars it can be seen to cover an area three quarters the size of the full moon. It lies 1.5 degrees east of 5th-magnitude Omega Pavonis. The nearest bright star is Peacock, which lies 3.25 degrees north and 9.25 degrees east.
Six X-ray sources have been identified in the cluster's core by the Chandra X-Ray Observatory.
Gallery
References
External links
http://seds.org/
Globular clusters
Pavo (constellation)
6752
093b | NGC 6752 | Astronomy | 404 |
39,350,622 | https://en.wikipedia.org/wiki/Steroidal%20alkaloid | Steroidal alkaloids have the basic steroidal skeleton with nitrogen-based functional groups attached to the skeleton. More specifically, they are distinguished by their tetracyclic cyclopentanoperhydrophenanthrene skeleton that marks their close relationship with sterols. They fall in two major categories: Solanum alkaloids and Veratrum alkaloids. A Steroidal alkaloid has also been found in Chonemorpha fragrans (Frangipani vine), 'chonemorphine' was used to treat intestinal infections in Wistar rats. (Chatterjee DK et al (1987) Parasitol Res 74, 1, 30-33).
Examples
Apocynaceae steroid alkaloids
The family of apocynaceae alkaloids can be categorized based on their backbone structure, which may include the 5α-pregnane, Δ5-pregnane, or conanine backbone. Typically, these alkaloids feature an amino group or an oxygen compound at the 3rd carbon atom. An illustrative example is latifolinin, which is derived from the conanine backbone. This distinctive structure is characterized by a five-membered ring formed by an amino group bonded to both the 18th and 20th carbon atoms.
Latifolinin is a compound that is naturally present in the bark of Funtumia latifolia. Additionally, the leaves of this plant contain two other compounds, namely funtumin and funtumidin. These compounds belong to the Apocynaceae steroid alkaloids family and share the 5α-pregnan backbone structure.
Batrachotoxins
Batrachotoxins are neurotoxins that are naturally occurring on the dermal surface of poison dart frogs. The photo shows the Phyllobates terribilis. Batrachotoxins share a structural foundation with pregnanes, consisting of 21 carbon atoms, and are distinctive for the amino group attached to the 18th carbon atom, exemplified by batrachotoxin A (see image).
Bufotoxins
The bufotoxins are named after the genus of Bufo. The α-pyranones at the 17th carbon atom are specific for the bufotoxins. The bufotoxin shown here is a sterane derivative with an α-pyranone at the 17th carbon atom and an esterified succinic acid at the 3rd carbon atom with arginine attached.
Buxus steroid alkaloids
Buxus steroid alkaloids are present in the leaves of the common boxwood (Buxus sempervirens). This plant primarily thrives in southern and central Europe. These alkaloids are characterized by an amino group attached to the 3rd and/or 20th carbon atom. Methylation of the amino groups can be partial, complete, or absent. Buxus steroid alkaloids constitute a substantial group of bases, most of which can be categorized into three distinct groups.
Another subgroup of Buxus steroid alkaloids possesses a tetracyclic structure. In these compounds, a bond exists between the 9th and 19th carbon atoms, forming a seven-membered ring (ring B). Buxamine E serves as an example of this group.
The third major group is distinguished by the absence of additional carbon atoms bonded to the 4th carbon atom of the A ring. Buxandonin L is an illustrative member of this category.
The largest group consists of pentacyclic Buxus steroid alkaloids, featuring a core structure based on 4,4,14-trimethyl-9,19-cyclopregnan. Cyclobuxin D is a representative of this particular group.
The Buxus steroid alkaloids buxamine E, buxandoline L, and cyclobuxin D are found in the leaves of common boxwood (buxus sempervirens).
Salamander alkaloids
The toxic salamander alkaloids occur naturally in organisms classified within the genus Salamandra. These alkaloids are derived from 3-aza-A-homo-5β-androstane. One notable example is samandarin (see figure), which may serve as the primary alkaloid depending on the species, although it may not be present in some other organisms at all. Samandarin possesses a distinctive oxazolidine structure within the A ring. Besides samandarin, there are several other steroid alkaloids in Salamandra organisms such as samandaridin, samandarone, and cycloneosamandione.
Solanum alkaloids
These compounds generally appear as their corresponding glycoside in plants of the genus Solanum. Solanum includes plants like potatoes, tomatoes, and various nightshades Starting with cholesterol, the biosynthesis of these compounds follow a similar general mechanism including hydroxylation, oxidation, and transamination before differentiating. Alkaloids found in these plants include chaconine, solanine, solasodine, tomatidine, tomatine, and solanidine. The Itkin group has found several of the biosynthetic gene clusters for these. In Itkin et al. 2011 and Itkin et al. 2013 they find several BSGs for α-tomatine in tomato and α-solanine in potato. Typically they are used in plants as a protection mechanism against animals. Due to the typical anti-cholinesterase activity, they can be used as poisons against the plants' predators. They can be used as starting materials for steroidal drugs. There are various tests for identifying these alkaloids. The characteristic test involves dissolving the compound in hot amyl alcohol or ethanol and watching for the formation of a jelly-like product as the mixture cools.
Solanidan skeleton
Steroidal alkaloids with a solanidan backbone exhibit a distinctive bicyclic structure, which replaces the cholesterol side chain on the D-ring. A notable example is solanocapsin, as discovered in the coral shrub (Solanum pseudocapsicum).
Spirosolan backbone
Another category of solanum alkaloids is based on the spirosolane skeleton. In these compounds, the E-ring is a tetrahydrofuran to which a piperidine is directly attached via a spiro compound. An example of such a steroid alkaloid is tomatidenol, which is prevalent across various species within the genus Solanum.
Veratrum alkaloids
Veratrum alkaloids of white/green chervil
The veratrum alkaloids derive their name from the white and green germer plants (Veratrum album and Veratrum viride, respectively). These plants belong to the Liliaceae family. Among them, procevin is a special case, as it features a nitrogen atom from piperidine connected to the 18th carbon.
Veratramine is an example of veratrum steroid alkaloids, characterized by a 22,26-epimino-14-abeo-cholestane ring system as their basis.
Veratrum alkaloids of sabadill
Veracevin is a member of the veratrum alkaloids group. However, this occurs in the sabadilla (Schoenocaulon officinale), which also belongs to the Liliaceae family. The veracevin is based on the cevan skeleton, in which the C-ring is a five-membered instead of a six-membered ring and the D-ring is a six-membered ring. Furthermore, the high number of hydroxy groups is still remarkable.
Veratrum alkaloids
True to their name, Veratrum alkaloids come from plants of the genus Veratrum. Alkaloids are found in the roots and rhizomes of these plants. They include veratridine, cyclopamine, and jervine. Because of their actions on the cardiovascular, neuromuscular, and respiratory systems, Veratrum alkaloids have been used for the treatment of various conditions like myasthenia gravis, hypotension, and eclampsia.
Bioactivity
Steroidal alkaloids have been investigated for a wide range of potential bioactivities including antimicrobial, anti-inflammatory, anti-estrogenic, and chemotherapeutic activity. These bioactivities are the result of a wide array of mechanisms across different compounds. For example, solasodine antimicrobial bioactivity is accomplished by interfering with the synthesis of genetic substances in Saccharomyces cerevisiae and Prototheca wickerhamii. Solasodine inhibits growth signaling in Geim original algal. On the other hand, tomatidine synergistically works with aminoglycosides as antibiotics against S. aureus.
Antiinflammation is similarly accomplished with a variety of mechanisms. Solasodine, for example, reduces interleukin-2 and -8 production whereas tomatidine inhibits specific nuclear translocation, JNK activation, as well as induce nitrous oxide synthase. Lastly, nine steroidal alkaloids have significant antiestrogenic activity whereas seven inhibit estrone sulfatase.
However, in addition to their therapeutic benefits, steroidal alkaloids, specifically veratrum alkaloids, are potentially deadly.
Veratrum alkaloid compounds act by attaching to voltage-gated sodium ion channels, altering their permeability. Veratrum alkaloids cause affected sodium channels to reactivate 1000x slower than unaffected channels. Furthermore, veratrum alkaloids block inactivation of sodium channels and lower their activation threshold so they remain open even at resting potential. As a result, sodium concentrations within the cell rise, leading to increased nerve and muscle excitability. These biochemical channels cause muscle contractions, repetitive firing of the nerves and an irregular heart rhythm caused by stimulation of vagal nerves which control the parasympathetic functions of the heart, lungs and digestive tract.
References | Steroidal alkaloid | Chemistry | 2,115 |
18,874,856 | https://en.wikipedia.org/wiki/Quality%20intellectual%20property%20metric | The quality intellectual property metric (QIP) is an international standard, developed by Virtual Socket Interface Alliance (VSIA) for measuring Intellectual Property (IP) or Silicon intellectual property (SIP) quality and examining the practices used to design, integrate and support the SIP. SIP hardening is required to facilitate the reuse of IP in integrated circuit design.
Background and importance
Many computer processors use a system-on-a-chip (SoC) design, which is intended to include all of a device's functions on a single chip. As a result, these chips need to include numerous technical standards that the device will use. One solution to designing such a chip is the reuse of high quality IP. Reusing IP from others means that the chip designer does not need to redesign these elements. IP quality is the key to successful SoC designs, but it is one of the SoC’s most challenging problems.
QIP metric allows both the IP designers and IP integrators to measure the quality of an IP core against a checklist of critical issues.
IP integrators make use of the IP cores into their own design and deliver final integrated circuit for an application, e.g. an integrated circuit designer of iPhone main processor IC (ARM architecture CPU) integrates other IP cores like USB 2.0, DSP, MP4 decoder, etc., so that the additional features of USB 2.0, MP4 decoder, etc. can be easily embedded into the final IC.
The QIP typically consists of interactive Microsoft Excel spreadsheets with sets of questions to be answered by the IP vendor.
SIP quality measure framework
Hong Kong Science and Technology Parks Corporation (HKSTP) and Hong Kong University of Science and Technology (HKUST) started to develop a SIP verification and quality measures framework in 2005, based on QIP metric. The objective is to develop a technical framework for SIP quality measures and evaluation based on QIP. Third-party SIP evaluation service is provided by HKSTP, so that IP integrators can know the quality of their desired SIP cores.
Integrated circuit (IC) designers have developed their own IC design, and such design can be reused by other IC designers. Other IC designers can reduce their risk of IC design, because such parts of design (IP cores) are well established and known to work well. But other IC designers do not know the quality of such IP cores provided. The original IP providers cannot provide the IP cores to other IC designers for evaluation, as it could allow competitors to steal their technologies. The solution is to have a third-party review the quality and value of the IP.
HKSTP is the third party between them and can act as a judge body, to evaluate the quality of IP cores of various IP providers, based on the public standard QIP metric. Other IP designers can know and choose their IP provider, based on the information provided by the third party, HKSTP. The IP providers can also get the evaluation report and improve the quality of their IP cores.
Soft and hard SIP
There are soft SIP and hard SIP verification and quality measures.
Soft IP comes with design source code in the form of synthesizable HDL (Hardware description language) code (VHDL and Verilog are HDL).
Hard IP is a design macro and model without HDL code available; they are optimized for power, size or performance, and mapped to a specific Process technology. Also refer to SIP hardening.
References
Electronic engineering
Electronic design
Integrated circuits | Quality intellectual property metric | Technology,Engineering | 718 |
12,349,567 | https://en.wikipedia.org/wiki/Drain%20%28plumbing%29 | A drain is the primary vessel or conduit for unwanted water or waste liquids to flow away, either to a more useful area, funnelled into a receptacle, or run into sewers or stormwater mains as waste discharge to be released or processed.
In most systems, the drain is for discharge of waste fluids, such as the drain in a sink in which the water is drained when it is no longer needed. In the UK, plumbers refer to waste water as "bad water", under the premise that the water they are moving from one area to another via the use of a drain is not needed and can be removed from the area, like a "bad apple" being removed from a fruit bowl.
Design, installation, and maintenance
Drain design and installation parameters are engineered to ensure drain functionality for its intended purpose, allowing for variances in volume, matter to be conveyed and maintenance requirements. Drain installation takes into account principles related to gravity, vacuum, grade, health hazards from biological agents, and resistance to functional failure. Also incorporated in drain design are requirements to allow drain maintenance and repair of a blocked drain, such as cleanout access.
Safety
Swimming pools and fountains
In systems such as swimming pools or fountains where waste fluid is recirculated, the drain is the input to the Recirculating Pumping machine. These fixtures can be very dangerous because people do not expect to encounter more than the head pressure of water above the drain when contacting a drain. When there is a recirculating pump, the force of suction consists of the head of water, plus the suction of the pump (up to a maximum of 1 atmosphere).
Fatalities have occurred around drains as a result of suction entrapment (also known as pool suction-drain injury). In these situations, a portion of the body, hair, or clothing may become stuck against the drain and may become impossible to release, resulting in drowning. For example, in 1994, Cristin Fitzpatrick drowned in a Variety Village swimming pool when her hair became entangled in a water funnel.
Properly designed drains in swimming pools and spas mitigate this hazard by either adding multiple drains, or increasing the surface area of the drain opening with the use of many holes or safety covers. Since drain suction increases rapidly when a portion of the drain flow is blocked, having two drains or a larger drain inlet allows alternative suction paths for the inflow. Also, swimming pool safety devices are available to automatically turn off an operating pump if a rapid increase in suction is detected, as could happen during a suction entrapment incident.
While fear of the drain may be counterproductive, children should be taught not to intentionally touch or attempt to block components of a swimming pool recirculation system.
Since children often play in public fountains, the use of multiple drains is a mandatory safety feature, regardless of whether or not the architect or planner intends that the fountain be used as an aquatic play feature. This is to ensure minimal risk of plumbing entrapment, but vandals can sometimes break into drains in the night time and remove the covers (commonly known as "drain mugging"), leaving them in a hazardous condition.
Legislation
On December 17, 2007, the national Virginia Graeme Baker Pool and Spa Safety Act was passed into law in the US. This law seeks to bring an end to suction entrapment related injuries and deaths by incorporating consumer protection regulation of pool and spa drains.
Drain covers
A drain cover is a cover with holes (e.g. a manhole) or a grating used to cover a drain, to prevent unwanted entry of foreign objects, or injury to people or animals. It allows drainage of liquids but prevents entry from large solid objects, and thus acts as a coarse filter. A sink drain cover is a drain cover used to cover the sink drain.
Maintenance
Blocked drains are a common problem in bathrooms and kitchens. In some cases, a chemical drain cleaner can clear the blockage, or a drain snake or augur can be used to mechanically clear the blockage. Disassembly of drain pipes can be an effective method of clearing severe blockages, especially if caused by the presence of a solid object. Sometimes, a licensed plumber is needed to rectify more fundamental issues with the installation. Blocked drains, if left long enough, can develop into a health hazard as the presence of mold and bacteria increases.
Standards
The American Society of Mechanical Engineers publishes the following standards:
A112.6.3 – Floor and Trench Drains
A112.6.4 – Roof, Deck, and Balcony Drains
See also
Domestic water system
Drain (HVAC)
Drainage system (disambiguation)
Piping and plumbing fitting
Plumbing
Plumbing drainage venting
Septic system
Sewage collection and disposal
Trench drain (Channel drain)
References
Plumbing
Drainage | Drain (plumbing) | Engineering | 984 |
60,138,013 | https://en.wikipedia.org/wiki/Korakrit%20Arunanondchai | Korakrit Arunanondchai () is a video and multimedia artist originally from Bangkok who now splits his time between Brooklyn and Bangkok. He is best known for his 2017 installation, With history in a room filled with people with funny names 4, which received widely positive reviews and was recognized with an award at the International Film Festival Rotterdam.
Early life
Arunanondchai was born in Bangkok, Thailand in 1986. His father was a first-generation Thai whose family had immigrated from China, while his mother grew up in several countries due to her father's position as a diplomat. He acquired an interest in the arts through music, which expanded to include visual art while studying at NIST International School in Bangkok. Upon graduating from NIST, he attended Rhode Island School of Design and graduated with a Bachelor of Fine Arts in 2009 before going on to earn a Master of Fine Arts from Columbia University in 2012.
Career
Shortly after the completion of his MFA, Arunanondchai was named as one of the 2013 recipients of the Emerging Artist Grant from the Hort Mann Foundation, an award intended to support promising New York-based artists. His first professional work included participation in group showings at the SculptureCenter and Fisher Landau Center, as well as solo exhibitions in New York and Brussels. In 2014 Museum of Modern Art hosted his first solo museum exhibition, 2012-2055, which included both videos and paintings that explored the concept of transformation and his own evolution as an artist.
In 2018 Arunanondchai received the Ammodo Tiger Short Award at the International Film Festival Rotterdam for With history in a room filled with people with funny names 4, the fourth entry in his ongoing film series Together with history in a room filled with people with funny names. That same year he released the fifth entry, No history in a room filled with people with funny names 5, and also launched a Bangkok video-art festival with the inaugural event Ghost:2561, highlighting the connections between Thailand's strong tradition of animism and contemporary art. In 2019, Arunanonschai was commissioned by the Performa 19 biennial for which he created the performance Together. During the COVID-19 pandemic in 2020, a planned exhibition in New York was postponed due to the rapid spread of the coronavirus throughout the city. However, Arunanondchai's newest video exploring the death of his grandfather, Songs for dying, was shown in 2021 at the Kunsthall Trondheim gallery in Norway and at the Gwangju Biennale in South Korea.
References
Living people
Korakrit Arunanondchai
Video artists
Multimedia artists
Korakrit Arunanondchai
1986 births
Columbia University School of the Arts alumni
Rhode Island School of Design alumni
Artists from Brooklyn | Korakrit Arunanondchai | Technology | 549 |
25,067,922 | https://en.wikipedia.org/wiki/Austin%20Gerard%20Smith | Austin Gerard Smith (born 1960) is a professor at the University of Exeter and director of its Living Systems Institute. He is notable for his pioneering work on the biology of embryonic stem cells.
Education
Austin Smith obtained his doctoral degree from the University of Edinburgh in 1986.
Career and research
He then carried out postdoctoral research at the University of Oxford, before joining the Centre for Genome Research at the University of Edinburgh as a group leader. In 1996, he was appointed director of the centre, which became the Institute for Stem Cell Research under his leadership. He remained as director of the Institute until his move to Cambridge in 2006. Here, he became a director of the Welcome Trust Centre for Stem Cell Research and later was the director of the new Wellcome Trust-MRC Cambridge Stem Cell Institute at the University of Cambridge, which was established with 8 million pounds ($12.5 million) awarded by the Wellcome Trust and Medical Research Council (UK) in 2012.
In 2019, he was appointed as the new Director of the University of Exeter's Living Systems Institute.
In 2003, Smith was awarded an MRC Research Professorship and elected to the Royal Society of Edinburgh. And in 2006, was elected a Fellow of the Royal Society. In 2010, he was co-recipient of the Louis-Jeantet Prize for Medicine along with French cardiologist Michel Haissaguerre.
In February 2010, together with 13 other leading stem cell researchers, he wrote an open letter to journal editors to voice the opinion that obstructive reviews by a small number of researchers in the field were hindering publication of novel stem cell research.
References
Living people
Wellcome Trust
Stem cell researchers
Fellows of the Royal Society
1960 births
Alumni of the University of Edinburgh
Academics of the University of Edinburgh | Austin Gerard Smith | Biology | 359 |
27,929,340 | https://en.wikipedia.org/wiki/Musical%20phrasing | Musical phrasing is the method by which a musician shapes a sequence of notes in a passage of music to allow expression, much like when speaking English a phrase may be written identically but may be spoken differently, and is named for the interpretation of small units of time known as phrases (half of a period). A musician accomplishes this by interpreting the music—from memory or sheet music—by altering tone, tempo, dynamics, articulation, inflection, and other characteristics. Phrasing can emphasise a concept in the music or a message in the lyrics, or it can digress from the composer's intention, aspects of which are commonly indicated in musical notation called phrase marks or phrase markings. For example, accelerating the tempo or prolonging a note may add tension.
Giuseppe Cambini—a composer, violinist, and music teacher of the Classical period—had this to say about bowed string instruments, specifically violin, phrasing:
Intuitive and analytical phrasing
"There are two schools of thought on phrasing," says flutist Nancy Toff: "one more intuitive, the other more analytical. The intuitive school uses a verbal model, equating the function of phrasing with that of punctuation in language. Thus, said Chopin to a student, 'He who phrases incorrectly is like a man who does not understand the language he speaks.'"
Problems linked with an analytical approach to phrasing occur particularly when the analytical approach is based only on the search for objective information, or (as is often the case) only concerned with the score:
According to Andranik Tangian,
analytical phrasing can be quite subjective, the only point is that it should follow a certain logic. For example, Webern’s Klangfarbenmelodie-styled orchestral arrangement of Ricercar from Bach’s Musical offering demonstrates Webern’s analytical phrasing of the theme, which is quite subjective on the one hand but, on the other hand, logically consistent:
Departing from Webern’s example, Tangian proposes not only phrasing/interpretation notation but also a model of performance, where the segments are selected both intuitively and analytically and are shown by tempo envelopes, dynamics and specific instrumental techniques.
Elision or reinterpretation
In the analysis of 18th- and 19th-century Western music, an elision, overlap, or rather reinterpretation (Umdeutung), is the perception, after the fact, of a (metrically weak) cadential chord at the end of one phrase as the (metrically strong) initial chord of the next phrase. Two phrases may overlap, making the beginning and ending of both happen at the same moment in time, or both phrases and hypermeasures may overlap, making the last bar in the first hypermeasure and the first in the second. Charles Burkhart uses overlap and reinterpretation to distinguish between the overlap of phrases and of both phrase and measure-group, respectively.
See also
Musical technique
Tempo rubato
References
Further reading
External links
Music performance
Rhythm and meter | Musical phrasing | Physics | 640 |
70,308,280 | https://en.wikipedia.org/wiki/Guisinol | Guisinol is an antibacterial depside with the molecular formula C23H25ClO5 that has been isolated from the fungus Aspergillus unguis.
References
Further reading
Chloroarenes
Antibiotics
Esters | Guisinol | Chemistry,Biology | 51 |
28,652 | https://en.wikipedia.org/wiki/Outline%20of%20sociology | The following outline is provided as an overview of and topical guide to the discipline of sociology:
Sociology – the study of society using various methods of empirical investigation and critical analysis to understand human social activity, from the micro level of individual agency and interaction to the macro level of systems and social structure.
Nature of sociology
Definition
Sociology can be described as all of the following:
The study of society.
Academic discipline – body of knowledge given to - or received by - a disciple (student); a branch or sphere of knowledge, or field of study, that an individual has chosen to specialise in.
Field of science – widely recognized category of specialized expertise within science, and typically embodies its own terminology and nomenclature. Such a field will usually be represented by one or more scientific journals, where peer reviewed research is published. There are many sociology-related scientific journals.
Social science – field of academic scholarship that explores aspects of human society.
Essence of sociology
Overall
Sociology
Key themes across sociological research
Society
Globalization
Human behavior
Human environmental impact
Identity
Industrial revolutions 3 & 4
Social complexity
Social environment
Social equality
Social equity
Social power
Social stratification
Social structure
Branches of sociology
Multidisciplinary and interdisciplinary fields involving sociology
History of sociology
History of sociology
Timeline of sociology
Theoretical perspectives in sociology
Approaches
Positivism
Positivism (Empirical sociology)
Critical realist
Critical realism
Structural
Structuralism
Challenging structure
Social interactions
Behavioural
Psychoanalytic sociology
Social justice
Critical theory
Applied
Pure sociology
Ecological
Human ecology
Levels of analysis
Methodology and methods in sociology
General sociology concepts
Sociology by location
Sociologists
List of sociologists
Sociological publications
Sociology journals
Magazines
Sociology books
Sociological associations
Sociological associations
Academies
Related fields
See also
References
External links
SocioSite, a directory of sociology resources
Sections of American Sociological Association
Research Committees and Themes of International Sociological Association, AIS
Comités de Recherche de l'Association internationale des sociologues de langue française, AISLF
Liste des réseaux thématiques de l'Association Française de Sociologie, AFS
Sociology, Outline
Sociology
Sociology
Sociology | Outline of sociology | Biology | 404 |
55,486,999 | https://en.wikipedia.org/wiki/LysM%20domain | In molecular biology the LysM domain is a protein domain found in a wide variety of extracellular proteins and receptors. The LysM domain is named after the Lysin Motif which was the original name given to the sequence motif identified in bacterial proteins. The region was originally identified as a C-terminal repeat found in the Enterococcus hirae muramidase. The LysM domain is found in a wide range of microbial extracellular proteins, where the LysM domain is thought to provide an anchoring to extracellular polysaccharides such as peptidoglycan and chitin. LysM domains are also found in plant receptors, including NFP, the receptor for Nod factor which is necessary for the root nodule symbiosis between legumes and symbiotic bacteria. The LysM domain is typically between 44 and 65 amino acid residues in length. The structure of the LysM domain showed that it is composed of a pair of antiparallel beta strands separated by a pair of short alpha helices.
See also
Nod factor
References
Protein domains | LysM domain | Biology | 228 |
9,564,371 | https://en.wikipedia.org/wiki/Acid%20fuchsin | Acid fuchsin or fuchsine acid, (also called Acid Violet 19 and C.I. 42685) is an acidic magenta dye with the chemical formula C20H17N3Na2O9S3. It is a sodium sulfonate derivative of fuchsine. Acid fuchsin has wide use in histology, and is one of the dyes used in Masson's trichrome stain. This method is commonly used to stain cytoplasm and nuclei of tissue sections in the histology laboratory in order to distinguish muscle from collagen. The muscle stains red with the acid fuchsin, and the collagen is stained green or blue with Light Green SF yellowish or methyl blue. It can also be used to identify growing bacteria.
See also
New fuchsine
Pararosanilin
Verhoeff’s Stain
Pollen grain staining (Alexander's stain)
References
Staining dyes
Triarylmethane dyes
Anilines
Benzenesulfonates | Acid fuchsin | Chemistry | 209 |
1,150,012 | https://en.wikipedia.org/wiki/Automator%20%28macOS%29 | Automator is an application developed by Apple Inc. for macOS, which can be used to automate repetitive tasks through point-and-click or drag and drop.
Automator enables the repetition of tasks across a wide variety of programs, including Finder, Safari, Calendar, Contacts and others. It can also work with third-party applications such as Microsoft Office, Adobe Photoshop or Pixelmator. The icon features a robot holding a pipe, a reference to pipelines, a computer science term for connected data workflows. Automator was first released with Mac OS X Tiger (10.4).
Features
Automator documents are called workflows, and are made up of actions. Workflows are run sequentially, with each action being given the previous action's output, which it can then process or act upon. Variables can be specified, which can be modified or processed by subsequent actions. Workflows can also incorporate loops and variables. Automator comes with a library of actions (file renaming, finding linked images, creating a new mail message, etc.). Actions can also run custom scripts, including AppleScript, JavaScript, or shell scripts. Workflow documents can be run directly in Automator or saved as applications that run the workflow when launched. Workflows can also be added to the contextual menu, to process any selected text or file.
, Microsoft has bundled Automator actions with Microsoft Office, which can be used to automate Outlook, Word, Excel, or PowerPoint.
The following is a non-exhaustive list of Automator's features:
General
Simulate the pressing of any key on the keyboard at specified intervals
Run AppleScript, JavaScript, Python, Ruby scripts, or shell scripts
Create Folder Actions, a Finder feature that applies certain workflows to all files in a folder
Create Services, which can be started in the Services menu
Automator can integrate with iCal, to launch workflows at an iCal event's specified time and date (and the event can be set to repeat automatically)
Automator can also launch workflows with programmable voice commands (called Dictation Commands, added in OS X Yosemite)
Internet
Download webpages as PDF
Extract an RSS feed from a given URL, and extract article text contents from that feed
Compose new emails, with specified subject line and attachments (which can be an output from a previous Action)
Upload files to FTP servers
Multimedia
Control USB-connected cameras to take pictures at regular intervals
Perform Finder actions on images, including rotation, applying Quartz filters (like black & white), and converting audio and video files to different formats
Batch resize photos
Import audio files to iTunes, and add them to playlists
Play an iTunes playlist
Text and documents
Turn text files to audio files, using the Mac's built-in text-to-speech feature
Extract text from PDF files
Combine PDF documents
Extract annotations from PDFs
Move files across folders, into folders, or out of subfolders
Process strings text, including adding quotations around text or outputting word count
Print files; and when combined with the "Get Folder Contents" action, it can print all files in a "drop box" folder
Interface
Automator provides a graphical user interface for automating tasks without knowledge of programming or scripting languages. Tasks can be recorded as they are performed by the user or can be selected from a list. The output of the previous action can become the input to the next action.
The icon for Automator features a robot, known as Otto the Automator.
History
Starting in macOS Monterey, Automator exists alongside Shortcuts.
See also
References
External links
Apple's official Automator page
Apple's official Automator developer documentation
Automator.us, a site with examples and tools, by Sal Soghoian (AppleScript Product Manager at Apple) and others
Automator.us for Mac OS X Leopard (10.5) and newer
Automator.us for Mac OS X Tiger (10.4)
MacOS
Automation software
Proprietary software
Visual programming languages
2005 software | Automator (macOS) | Engineering | 859 |
26,296,965 | https://en.wikipedia.org/wiki/Chandra%E2%80%93Toueg%20consensus%20algorithm | The Chandra–Toueg consensus algorithm, published by Tushar Deepak Chandra and Sam Toueg in 1996, is an algorithm for solving consensus in a network of unreliable processes equipped with an eventually strong failure detector. The failure detector is an abstract version of timeouts; it signals to each process when other processes may have crashed. An eventually strong failure detector is one that never identifies some specific non-faulty process as having failed after some initial period of confusion, and, at the same time, eventually identifies all faulty processes as failed (where a faulty process is a process which eventually fails or crashes and a non-faulty process never fails). The Chandra–Toueg consensus algorithm assumes that the number of faulty processes, denoted by , is less than n/2 (i.e. the minority), i.e. it assumes < /2, where n is the total number of processes.
The algorithm
The algorithm proceeds in rounds and uses a rotating coordinator: in each round , the process whose identity is given by mod is chosen as the coordinator. Each process keeps track of its current preferred decision value (initially equal to the input of the process) and the last round where it changed its decision value (the value's timestamp). The actions carried out in each round are:
All processes send (r, preference, timestamp) to the coordinator.
The coordinator waits to receive messages from at least half of the processes (including itself).
It then chooses as its preference a value with the most recent timestamp among those sent.
The coordinator sends (r, preference) to all processes.
Each process waits (1) to receive (r, preference) from the coordinator, or (2) for its failure detector to identify the coordinator as crashed.
In the first case, it sets its own preference to the coordinator's preference and responds with ack(r).
In the second case, it sends nack(r) to the coordinator.
The coordinator waits to receive ack(r) or nack(r) from a majority of processes.
If it receives ack(r) from a majority, it sends decide(preference) to all processes.
Any process that receives decide(preference) for the first time relays decide(preference) to all processes, then decides preference and terminates.
Note that this algorithm is used to decide only on one value.
Correctness
Problem definition
An algorithm which "solves" the consensus problem must ensure the following properties:
termination: all processes decide on a value;
agreement: all processes decide on the same value; and
validity: all processes decide on a value that was some process's input value;
Assumptions
Before arguing that the Chandra–Toueg consensus algorithm satisfies the three properties above, recall that this algorithm requires = 2* + 1 processes, where at most f of which are faulty.
Furthermore, note that this algorithm assumes the existence of eventually strong failure detector (which are accessible and can be used to detect the crash of a node). An eventually strong failure detector is one that never identifies some specific non-faulty (or correct) process as having failed, after some initial period of confusion, and, at the same time, eventually identifies all faulty processes as failed.
Proof of correctness
Termination holds because eventually the failure detector stops suspecting some non-faulty process p and eventually p becomes the coordinator. If the algorithm has not terminated before this occurs in some round r, then every non-faulty process in round r waits to receive p's preference and responds with ack(r). This allows p to collect enough acknowledgments to send decide(preference), causing every process to terminate. Alternatively, it may be that some faulty coordinator sends decide only to a few processes; but if any of these processes are non-faulty, they broadcast the decision to all the remaining processes, causing them to decide and terminate.
Validity follows from the fact that every preference starts out as some process's input; there is nothing in the protocol that generates new preferences.
Agreement is potentially the most difficult to achieve. It could be possible that a coordinator, in one round r, might send a decide message from some value v that propagates only to a few processes before some other coordinator, in a later round r', sends a decide message for some other value v'. To show that this does not occur, observe that before the first coordinator can send decide(v), it must have received ack(r) from a majority of processes; but, then, when any later coordinator polls a majority of processes, the later majority will overlap the earlier one and v will be the most recent value. So, any two coordinators that send out decide message send out the same value.
References
Chandra and Toueg. Unreliable failure detectors for reliable distributed systems. JACM 43(2):225–267, 1996.
Course notes at Yale on failure detectors.
Distributed algorithms
Fault-tolerant computer systems | Chandra–Toueg consensus algorithm | Technology,Engineering | 1,018 |
57,148,706 | https://en.wikipedia.org/wiki/Paleobiota%20of%20the%20London%20Clay | A list of prehistoric and extant species whose fossils have been found in the London Clay, which underlies large areas of southeast England.
Plant fossils, especially seeds and fruits, are found in abundance and have been collected from the London Clay for almost 300 years. Some 350 named species of plant have been found, making the London Clay flora one of the world's most diverse for fossil seeds and fruits. The flora includes plant types found today in tropical forests of Asia and demonstrates the much warmer climate of the Eocene epoch, with plants such as Nypa (Nipah palms) and other palms being frequently encountered. The following plants list is incomplete and is based on the research by Marjorie Chandler. and research works done by the paleobotanist Steven R. Manchester and by professor of plant palaeobiology Margaret Collinson.
Plants
Pteridophytes
Pteridaceae
Acrostichum – mangrove fern
Pteris sp. - brake
Vittaria sp. – shoestring fern, similar to Vittaria lineata
Cyatheaceae – scaly tree fern
Cyathea sp. – similar to Cyathea delgadii
Thyrsopteridaceae
Thyrsopteris sp. – similar to Thyrsopteris elegans
Osmundaceae
Osmunda sp. – similar to Osmunda javanica
Dryopteridaceae – wood fern, male fern
Dryopteris sp.
Athyriaceae
Diplazium sp. - similar to Diplazium smithianum
Onocleaceae
Onoclea sp. – similar to Onoclea sensibilis (the sensitive fern)
Nephrolepidaceae – macho ferns
Nephrolepis sp.
Salviniaceae – water ferns
Azolla
Marsilea – water clover
Marsilea sp. - similar to Marsilea quadrifolia
Lycopodiophytes
Lycopodiaceae – clubmosses
Lycopodium sp.
Phylloglossum sp. – similar to Phylloglossum drummondii (pygmy clubmoss)
Gymnosperms
Ginkgoaceae
Ginkgo sp.
Cycadaceae
Cycas sp. - similar to Cycas schumanniana
Zamiaceae
Zamia sp. – similar to Zamia pumila
Araucariaceae – monkey puzzle, bunya pine, and Norfolk pine
Agathis sp. - similar to Agathis dammara
†Araucarites spp.
†Doliostrobus stenbergi - fossils in the past named †Araucarites are said to be of this genus, it is now placed in its own family, †Doliostrobaceae.
Pinaceae
Pinus spp.
Taxaceae
?Taxaceae indet.
†Cephalotaxus bowerbanki – plum yew
Torreya sp.
Cupressaceae
†Callitris curta (Callitrites curta) – cypress pine
†Cupressinites spp.
Libocedrus adpressa
†Quasisequoia sp.
Sequoia couttsiae
Widdringtonia sp. – African cypresses
Podocarpaceae
Afrocarpus sp. – similar to Afrocarpus falcatus (common yellowwood)
Podocarpus argillaelondinensis?
Podocarpus sp. – similar to Podocarpus elatus (plum pine)
Podocarpus sp. – similar to Podocarpus novae-caledoniae
Podocarpus sp. – similar to Podocarpus nubigenus (Chilean podocarp, cloud podocarp)
Prumnopitys sp. – similar to Prumnopitys andina (the Chilean plum yew)
Angiosperms
Arecaceae – palms
†Caryotispermum cantiense
Corypha sp.
Livistona minima
Nypa burtini (syn. Nipa burtini)
Oncosperma anglica
†Palmospermum bracknellense
†Palmospermum cooperi
†Palmospermum davisi
†Palmospermum elegans
†Palmospermum jenkinsi
†Palmospermum minutum
†Palmospermum ornatum
†Palmospermum ovale
†Palmospermum subglobulare
Sabal grandisperma
Serenoa sp.
?Trachycarpus sp.
Cyclanthaceae
Cyclanthus lakensis
Cyperaceae - sedges
†Caricoidea obovata
†Polycarpella caespitosa
Posidoniaceae - seagrass family
Posidonia parisiensis
Nymphaeaceae – water lilies
†Protobarclaya eocenica
Victoria sp - similar to Victoria cruziana
Magnoliaceae
Liriodendron gardneri - tulip tree
Magnolia angusta
Magnolia crassa
Magnolia davisi
Magnolia lata
Magnolia lobata
Magnolia oblonga
Magnolia pygmaea
Magnolia rugosa
Magnolia subquadrangularis
Magnolia symmetrica
Myristicaceae - nutmeg family
†Myristicacarpum chandlerae
Annonaceae - the custard apple family
Alphonsea sp.
†Anonaspermum anonijorme - related to the genera Anonna and Polyalthia, most similar species is Annona muricata
†Anonaspermum cerebellatum - Uvaria, Melodorum and Orophea shows closest resemblance to the fossil
†Anonaspermum commune
†Anonaspermum complanatum - related to Anonna and Melodorum
†Anonaspermum corrugatum - related to the genera Anonna and Melodorum
†Anonaspermum minimum - related to Dasymaschalon clusiflorum
†Anonaspermum obscurum
†Anonaspermum ovale - related to the genera Anonna and Melodorum
†Anonaspermum pulchrum - related to Dasymaschalon clusiflorum
†Anonaspermum punctatum - related to the genera Bocagea, Orophea, Unonopsis, and Guatteria
†Anonaspermum rotundatum - distantly related to Polyauhia
†Anonaspermum rugosum
†Anonaspermum subcompressum
Asimina sp. - similar to Asimina reticulata
Orophea sp.
Polyalthia sp.
Rollinia sp.
Uvaria sp.
Lauraceae – avocado and cinnamon family
Beilschmiedia bognorensis
Beilschmiedia eocenica
Beilschmiedia gigantea
Beilschmiedia oviformis
Beilschmiedia pyriformis
Cinnamomum grande
Cinnamomum globulare
Cinnamomum oblongum
Cinnamomum ovoideum
†Crowella globosa
Endiandra spp.
†Laurocalyx bowerbanki
†Laurocalyx dubius
†Laurocalyx fibrotorulosus
†Laurocalyx globularis
†Laurocalyx magnus
†Laurocarpum crassum
†Laurocarpum cupuliferum
†Laurocarpum davisi
†Laurocarpum inornatum
†Laurocarpum minimum
†Laurocarpum minutissimum
†Laurocarpum ovoideum
†Laurocarpum paradoxum
†Laurocarpum proteum
†Laurocarpum pyrocarpum
†Laurocarpum sheppeyense
Litsea pyriformis
Ocotea sp.
†Protoaltingia europaea
†Protoravensara sheppeyensis
Aristolochiaceae - birthwort family
Aristolochia sp.
Schisandraceae
Illicium sp. - similar to Illicium floridanum
Dilleniaceae
Hibbertia bognorensis
Tetracera? cantiensis
Tetracera crofti
Tetracera eocenica
Platanaceae – sycamore or plane tree
†Plataninium decipiens
Proteaceae
Dryandra acutiloba
Fagaceae – beech, oak and chestnut family
†Quercinium pasanioides
Betulaceae – birch, alder and hornbeams
Alnus richardsoni (syn. Petrophiloides richardsoni) – an alder
Ticodendraceae
†Ferrignocarpus bivalvis
Myricaceae - wax-myrtle, bayberry family
Myrica boveyana
Juglandaceae – walnut, hickory and pecan family
†Juglandicarya bognorensis
†Juglandicarya cooperi
†Juglandicarya depressa - the most common Juglandacarya species in the London Clay
†Juglandicarya lubbocki
†Juglandicarya minuta
†Petrophiloides richardsoni - among the two most abundant Juglandaceae species in the London Clay
†Pterocaryopsis bognorensis - related to the genus Pterocarya
Trochodendraceae
Trochodendron pauciseminum
Haloragaceae
†Haloragicarya sp.
Sabiaceae
†Bognoria venablesi
Meliosma cantiensis
Meliosma jenkinsi
Meliosma sheppeyensis
Menispermaceae – moon seed family
†Bowerbankella tiliacoroidea
†Davisicarpum gibbosum
Diploclisia bognorensis
†Eohypserpa parsonsi
†Frintonia ornata
Hypserpa sp.
Jatrorrhiza sp.
†Menispermicarpum rariforme
†Menispermoxylon - close to the extant genus Tinomiscium
†Microtinomiscium foveolatum
†Palaeococculus lakensis
†Palaeosinomenium pulchrum
†Tinomiscoidea scaphiformis
Tinospora excavata
†Wardenia davisi
Cardiopteridaceae
Citronella sp.
Torricelliaceae
Toricellia sp. - very similar to Torricellia bonesii from the Clarno Formation of Oregon
Hamamelidaceae – witch-hazel family
Corylopsis? bognorensis
Corylopsis? latisperma
Corylopsis venablesi
†Jenkinsella sp.
†Protoaltingia europaea
Altingiaceae
Altingia sp.
Liquidambar palaeocenica - sweetgum
Oleaceae
Fraxinus sp.
Styracaceae
Styrax sp.
Theaceae
Camellia sp. - tea
Gordonia sp.
Stewartia sp.
Pentaphylacaceae
Eurya sp.
Symplocaceae – sapphire-berry, sweet leaf.
Symplocos curvata
Symplocos quadrilocularis
Symplocos trilocularis
Symplocos bognorensis
Ericaceae
?Leucopogon quadrilocularis
Lissanthe sp.
Rhododendron sp.
Sapotaceae
†Sapoticarpum rotundatum
†Sapoticarpum latum
†Sapoticarpum duhium
†Sapotispermum sheppeyense - allied to Chrysophyllum and Sideroxylon
Bataceae - saltwort or beachwort
Batis sp. - similar to Batis maritima
Myrtaceae
†Hightea elliptica
†Hightea turgida
†Myrtospermum variabile
†Palaeorhodomyrtus subangulata - allied to Rhodomyrtus
Staphyleaceae
?Tapiscia sp. - bladdernut
Fabaceae
Acacia sp. – similar to Vachellia farnesiana
Caesalpinia sp. - seed pods very similar to seed pods of C. claibornensis from the middle Eocene of Tennessee
Dalbergia sp.
†Leguminocarpon gardneri - seed pods most compatible to seed pods of species in Caesalpinia and Peltogyne
†Leguminocarpon nervosum
†Mimosites browniana
Rosaceae
Rubus sp.
Elaeagnaceae
Elaeagnus sp. - oleaster, silverberry
Myrsinaceae
Ardisia eocenica
Rhizophoraceae - mangrove
Ceriops sp.
†Palaeobruguiera elongata
†Palaeobruguiera lata
Salicaceae
Oncoba variabilis
†Oncobella sp.
† Saxifragispermum spinosissimum
Linaceae
†Decaplatyspermum bowerbanki
†Wetherellia variahilis - related to Hugonia
Nyctaginaceae - the four o'clock family
Pisonia sp. - the birdcatcher tree
Olacaceae
Erythropalum europaeum - Only one extant species of this genus which is a scandent shrubs or liana
Erythropalum jenkinsi
Erythropalum turbinatum
Olax depressa
Lamiaceae
Satureja sp.
Boraginaceae
Ehretia clausentia
Ehretia ehretioides
Heliotropium sp.
Solanaceae
†Cantisolanum daturoides
Datura sp. - similar to Datura ferox
Datura sp. - similar to Datura metel
Apocynaceae - the dogbane family
Allamanda sp.
†Ochrosella ovalis
†Ochrosoidea sheppeyensis
Burseraceae - the incense tree family
Boswellia sp.
†Bursericarpum aldwickense
†Bursericarpum bognorense
†Bursericarpum ovale
†Bursericarpum venablesi
†Palaeobursera bognorensis
†Protocommiphora europaea
Anacardiaceae
Choerospondias sheppeyensis
Dracontomelon minimum
Dracontomelon subglobosum
Lannea europaea
Lannea jenkinsi
†Lobaticarpum variabile
Mangifera sp. - mango
Odina europaea
Odina jenkinsi
Odina subreniformis
Poupartia sp.
†Pseudosclerocarya subalata
†Spondiaecarpon operculatum - according to several botanists, the pyritized specimens, originally described as Spondiaecarpon operculatum, represent locule casts of Torricellia sp.
†Xylocarya sp.
Onagraceae
†Palaeeucharidium cellulare - allied to Eucharidium
Lythraceae
†Cranmeria trilocularis
†Minsterocarpum alatum - closely related to the crape myrtle or crepe myrtle genus Lagerstroemia
†Pachyspermum quinqueloculare
†Tamesicarpum polyspermum
Malvaceae
†Cantitilia polysperma
Elaeocarpaceae
†Echinocarpus sheppeyensis
Moraceae – mulberry and fig family
Artocarpus sp. – breadfruit
Ficus sp. – fig
Maclura sp.
?Morus sp.
Urticaceae
†Urticicarpum scutellum
Euphorbiaceae - the spurge family
Aleurites sp.
Croton sp.
Euphorbia sp. – similar to Euphorbia cotinifolia
†Euphorbiospermum bognorense
†Euphorbiospermum cooperi
†Euphorbiospermum eocenicum
†Euphorbiospermum obliquum
†Euphorbiospermum subglobulare
†Euphorbiospermum subovoideum
†Euphorbiospermum venablesi
†Euphorbiotheca minima
†Euphorbiotheca sheppeyensis
†Lagenoidea bilocularis
†Lagenoidea trilocularis
Manihot sp. – cassava
†Wetherellia variabilis
Cucurbitaceae - the gourd family
†Cucurbitospermum cooperi
†Cucurbitospermum equiaelaterale
†Cucurbitospermum sheppeyense
†Cucurbitospermum triangulare
Vitaceae
Ampelopsis sp.
†Palaeovitis sp.
Tetrastigma corrugata
Tetrastigma davisi
Tetrastigma elliotti
Tetrastigma sheppeyensis:*†Vitacexoylon sp. - close to the extant genus Rhoicissus
Vitis bilobata
Vitis bognorensis
Vitis bracknellensis
Vitis elegans
Vitis longisulcata
Vitis magnisperma
Vitis obovoidea
Vitis platyformis
Vitis pygmaea
Vitis rectisulcata
Vitis semenlabruscoides
Vitis subglobosa
Vitis venablesi
Sapindaceae – soapberry
Atalaya sp. – similar to Atalaya variifolia from Australia
†Cupanoides grandis - related to Cupania
†Cupanoides tumidus - related to Cupania
†Palaeallophylus minimus
†Palaeallophyllus ovoideus
†Palaeallophylus rotundatus
†Palaealectryon spirale
†Sapindospermum cooperi
†Sapindospermum davisi
†Sapindospermum grande
†Sapindospermum jenkinsi
†Sapindospermum ovoideum
†Sapindospermum revolutum
†Sapindospermum subovatum
Toechima sp.
Meliaceae - the mahogany family
Cedrela sp.
†Melicarya variabili
Toona sulcata
Rutaceae - the rue family
†Canticarya gracilis
†Canticarya ovalis
†Canticarya sheppeyensis
†Canticarya ventricosa
†Caxtonia elongata
†Caxtonia glandulosa
†Caxtonia rutacaeformis
†Citrispermum sheppeyense
†Clausenispermum dubium
†Eozanthoxylon glandulosum
Euodia costata
†Rutaspermum bognorense
†Rutaspermum minimum
†Shrubsolea jenkinsi
†Zanthoxylon compression
†Zanthoxylon bognorense
Celastraceae - the staff vine or bittersweet family
†Canticarpum celastroides
Catha sp. – most similar to Catha edulis (Khat)
†Cathispermum pulchrum
†Celastrinoxylon ramunculiformis
Sterculiaceae
Dombeya sp.
†Sphinxia ovalis
Cornaceae
†Beckettia mastixioides
Cornus ettingshausenii
†Dunstania ettinghauseni
†Dunstania multilocularis
†Langtonia bisulcata
†Lanfrancia subglobosa
Mastixia cantiensis
Mastixia grandis
Mastixia parva
†Portnallia bognorensis
†Portnallia sheppeyensis
Nyssaceae - the tupelo family
Nyssa bilocularis
Nyssa cooperi
†Palaeonyssa multilocularis
Curtisiaceae
Curtisia quadrilocularis
Alangiaceae
Alangium jenkinsi
Icacinaceae
†Faboidea crassicutis
†Icacinicarya amygadaloidea
†Icacinicarya bartonensis
†Icacinicarya becktonensis
†Icacinicarya bognorensis
†Icacinicarya echinata
†Icacinicarya elegans
†Icacinicarya emarginata
†Icacinicarya forbesii
†Icacinicarya foveolata
†Icacinicarya glabra
†Icacinicarya inornata
†Icacinicarya jenkinsi
†Icacinicarya minima
†Icacinicarya mucronata
†Icacinicarya nodulifera
†Icacinicarya ovalis
†Icacinicarya ovoidea
†Icacinicarya platycarpa
†Icacinicarya pygmaea
†Icacinicarya reticulata
†Icacinicarya rotundata
†Icacinicarya transversalis
Iodes acutiform
Iodes bilinica
Iodes corniculata
Iodes davisii
Iodes eocenica
Iodes multireticulata
Mappia sp.
Miquelia sp.
Natsiatum eocenicum
†Palaeophytocrene ambigua
†Palaeophytocrene foveolata
†Perforatocarpum echinatum
†Sphaeriodes ventricosa
†Stizocarya communis
Animals
Animal fossils include bivalves, gastropods, nautilus, worm tubes, brittle stars and starfish, crabs, lobsters, fish (including shark and ray teeth), reptiles (particularly turtles), and a large diversity of birds. A few mammal remains have also been recorded. Preservation varies; articulated skeletons are generally rare. Of fish, isolated teeth are very frequent. Bird bones are not infrequently encountered compared to other lagerstätten, but usually occur as single bones and are often broken.
The following fauna species list follows Clouter (2007).
Vertebrates
Mammals
Argillotherium
Coryphodon eocaenus – a pantodont
Hyracotherium – a palaeothere
Oxyaena – a creodont
Platychoerops richardsoni - from Herne Bay, a primate belonging to the order Plesiadapiformes
Birds
Anatalavis oxfordi – a waterbird possibly related to the magpie-goose of Australia
Archaeodromus - an archaeotrogonid
Argillipes – perhaps a landfowl
Coturnipes – a quail-like bird
Danielsraptor – a masillaraptorid falconiform, closely related to Masillaraptor
Dasornis – a pseudotooth bird
Eocolius – a coliiform
Eostrix – an owl
Gastornis – from the Isle of Grain, a very large flightless galloansere
Halcyornis – a parrot or roller relative
Lithornis – a paleognath
Lutavis – a possible afroavian
Nasidytes – a loon
Odontopteryx – a pseudotooth bird
Parvigyps – perhaps a diurnal raptor
Pediorallus – a paleognath or landfowl
Percolinus – perhaps a landfowl
"Precursor" – apparently a chimera of Charadriiformes and Psittaciformes (and possibly other) bones
Primapus – a swift-like bird
Primodroma – a tubenose, possibly a storm-petrel
Promusophaga – a paleognath
Prophaeton – a tropicbirds relative
Proherodius – a waterbird
Proplegadis – a stork or ibis
Pseudodontornis – a pseudotooth bird
Psittacomimus – a psittacopedid, closely related to Parapsittacopes
Pulchrapollia – a parrot relative
Stintonornis – probably a hawk relative
Tynskya – a messelasturid related to passerines and parrots
Waltonavis – a possible leptosomiform
Ypresiglaux – a basal strigiform
ReptilesCrocodylians Diplocynodon – an alligatoroid
Kentisuchus spenceri – a crocodylidSnakes Palaeophis toliapicus and P. typhaeusTurtles and tortoises'''
Allaeochelys – a pig-nosed turtle
Argillochelys, Eochelone, Puppigerus and "Thalassochelys" sp. – true sea-turtles
Chrysemys bicarinata and C. testudiniformis – pond turtles
Eosphargis – a leatherback sea-turtle
Homopus comptoni – a tortoise
Lytoloma crassicostatum and L. planimentum – prehistoric sea-turtles
Palemys bowerbanki – a bothremydid
Trionyx pustulatus and T. sp. – softshell turtles
Dacochelys and Pseudotrionyx – incertae sedisBony fish
Acestrus elongatus, A. ornatus, Aglyptorhynchus sulcatus, A. venablasi, Xiphiorhynchus parvus and X priscus – swordfish relatives
Acipenser toliapicus – a true sturgeon
Albula oweni – a bonefish
Ampheristus toliapicus – a scorpionfish
Ardiodus marriotti – incertae sedis Argillichthys toombsi – a lizardfish relative
Aulopopsis depressifrons, A. egertoni and Labrophagus esocinus – flagfins
Beerichthys ingens and B. sp. – Two species of luvar or luvar-like fish
Bramoides brieni and Goniocranion arambourgi – pomfrets
Brychaetus muelleri – an arowana
Bucklandium diluvii – a naked catfish
Cylindracanthus rectus and Hemirhabdorhynchus elliotti – Blochiidae
Cymbium proosti, Eocoelopoma colei, E. curvatum, E. gigas, E. hopwoodi, Eothynnus salmoneus, Scombramphodon crassidens, S. sheppeyensis, Scombrinus macropomus, S. nuchalis, Sphyraenodus priscus, Tamesichthys decipiens, Wetherellus brevior, W. cristatus, W. longior and Woodwardella patellifrons – mackerel and tuna relatives
Diodon sp. – a porcupinefish
Egertonia isodonta and Phyllodus toliapicus – Phyllodontidae
Elops sp., Esocelops cavifrons, Megalops oblongus, M. priscus, Promegalops sheppeyensis and P. signeuxae – ladyfish
Enniskillenus radiatus – acanthomorph
Eutrichurides winkleri – a cutlassfish
Halecopsis insignis – Halecopsidae
Laparon alticeps – spadefish
Lehmanamia sheppeyensis – a bowfin
Myripristis toliapicus, Naupygus bucklandi and Paraberyx bowerbanki – soldierfish
Percostoma angustum, Plesioserranus cf. wemmeliensi and Serranopsis londinensis – groupers
Podocephalus curryi, P. nitidus, Sciaenuropsis turneri and Sciaenurus bowerbanki – porgies
Progempylus edwardsi – a snake mackerel
Pseudosphaerodon antiquus and P. navicularis – wrasses?
Pycnodus bowerbanki and P. toliapicus – Pychnodontidae
Rhinocephalus planiceps and Trichurides sagittidens – hakes
Rhynchorhinus branchialis and R. major – Eccelidae
Tetratichthys antiquitatis – a jack mackerel
Whitephippus tamensis – a lampriform
Cartilaginous fish
Abdounia beaugi, Carcharhinus sp. and Physogaleus secundus – requiem sharks
Aetobatis irregularis, Burnhamia daviesi, Myliobatis dixoni, M. latidens, M. raouxi and M. toliapicus – eagle rays
Anomotodon sheppeyensis – a goblin shark
Carcharias hopei, Jaekelotodus trigonalis, Odontaspis winkleri, Palaeohypotodus rutoti and Striatolamia macrota – sand sharks
Edaphodon bucklandi and Elasmodus hunteri – chimaeras
Dasyatis davisi and D. wochadunensis – stingrays
Galeorhinus lefevrei, G. minor, G. recticonus, G. ypresiensis, Mustelus whitei and Triakis wardi – hound sharks
Heterodontus vincenti, H. wardenensis and H. woodwardi – bullhead sharks
Hexanchus agassizi, H. collinsonae, H. hookeri, Notorhynchus serratissimus and Weltonia burnhamensis – cow sharks
Isisteus trituratus and Squalus minor – dogfish sharks
Isurolamna affinis, Isurus nova, I. praecursor, Lamna inflata, L. lerichei, Otodus obliquus, O. aksuaticus and Xiphodolamia eocaena – white sharks
Megascyliorhinus cooperi, Scyliorhinus casieri, S. gilberti, S. pattersoni and S. woodwardi – catsharks
Pararhincodon sp? – an indeterminate shark
Raja sp.? – an indeterminate ray
Squatina prima – an angel shark
Crustaceans
Lobsters and shrimp
Archiocarabus bowerbankiCallianassa sp.Homarus morrisi Hoploparia gammaroidesLinuparus eocenicus & L. scyllariformisScyllarides tuberculatusScyllaridia koenigiThenops scyllariformisBarnaclesArcoscapellum quadratumScalpellum minutum and S. quadratumCrabsBasinotopus lamarckii Desmarest Campylostoma mutatiformeCyclocorystes pulchellusDromilites bucklandi & D. lamarkiGlyphthyreus wetherelliGoniochela angulata Desmarest Harpactoxanthopsis cf. quadriloMithracia libinioidesOediosoma ambiguaPortunites incerta & P. stintoniXanthilites bowerbankiZanthopsis bispinosa, Z. dufori, Z. leachei, Z. nodosa and Z. unispinosaMantis shrimp
Squilla wetherelliMolluscs
Cephalopods
Aturia ziczac, Cimomia imperialis, Deltoidonautilus sowerbyi, Euciphoceras regale, Eutrephoceras urbanum, Hercoglossa cassiniana and Simplicioceras centrale – nautiluses
Belopterina levesquei, Belosepia blainvillei and B. sepioidea – cuttlefish
Bivalves
Abra splendens – Semelidae
Amygdalum depressum and Modiolus tubicola – Mytilidae
Anomiidae
Anomia scabrosa – a jingle shell
Enigmonia aenigmatica – a jingle shell
Arca nitens, A. tumescens and Glycymeris wrigleyi – ark clams
Arctica planata – Arcticidae
Astarte davisi, A. filigera and A. rugata –
Astartidae
Calpitaria sulcataria – a venus clam
Corbula globosa – Corbulidae
Cuspidaria inflata and C. lamallosa – Cuspidariidae
Nuculana amygdaloides and N. prisca – Nuculanidae
Lentipecten corneus and Pecten sp. – scallops
Nemocardium nitens and N. semigranulatum – Cardiidae
Nucula consors – Nuculidae
Ostrea sp. – a true oysters
Pinna affinis – a pen shell
Pleurolectroma media and Pteria papyracea – pearl oysters
Pycnodonte gryphovicina – Pycnodontidae
Teredina personata and Teredo sp. – shipworms
Thyasira angulata – Thyasiridae
Thyasira goodhali – Thyasiridae
Venericardia trinobantium – Carditidae
Verticordia sulcata – Verticordiidae
Gastropods
Acrilla cymaea, Foratiscala perforata, Litoriniscala scalaroides and Undiscala primaeva – wentletraps
Aporrhais sowerbii and Eotibia lucida – true conchs
Bathytoma granata, B. turbida, Clavatula conica, Cochlespira gyrata, Conolithus concinnus, Endiatoma cerithiformis, Fusiturris selysi, F. simillima, F. wetherelli, Gemmula koninckii, Hemipleurotoma fasciolata, H. prestwichi, Pseudotoma topleyi, Surculites errans, S. velatus, Turricula crassa, T. helix, T. latimarginata, T. nanodis, T. symmetrica and T. teretrium – Conoidea
Bonellitia clathratum and B. laeviuscula – nutmeg shells
Bullinella sp., Crenilabium elongatum, ?Roxiana sp., Scaphander ?parisiensis and Tornatellaea simulata – opisthobranchs
Camptoceratops prisca, Spiratella mercinensis, S. taylori and S. tutelina – sea-butterflies
Cassis striata and Mambrina gallica – tun shells
Cepatia cepacea, Daphnobela juncea, Litiopa sulculosa, Orthochetus elongatus and Stellaxis pulcher – incertae sedis Eocypraea oviformis – a cowrie
Euspira glaucinoides and Sinum clathratum – moon snails
Falsifusus londini, Fusinus coniferus, F. wetherelli, Pseudoneptunea curta, Siphonalia highgatensis, Streptolathyrus triliniatus, S. zonulatus, Wrigleya complanata and W. transversaria – true whelks
Ficopsis multiformis – a fig shell
Lacunella sp. – a periwinkle
Mathilda sororcula – Mathildidae
Murex subcristatus and Paziella argillacea – murex snails
Pachysyrnola sp. and Turbonilla subterranea – pyramid shells
Patella sp. – Patellidae
Ptychatractus aff. interuptus, Scaphella wetherelli and Volutospina nodosa – volutes
Rilla cf. tenuistriata – Streptaxidae
Ringicula turgida – Ringiculidae
Sassia morrisi – a triton shell
Sigapatella sp. – Calyptraeidae
Tornus sp. and Turboella cf. misera – Rissoidae
Xenophora extensum – a carrier shell
Tusk shells
Antalis anceps and A. nitensEchinoderms
Asteropecten crispatus, Coulonia colei, Hemiaster bowerbanki, Hippasteria tuberculata, Ophioglypha wetherelli and Teichaster stokesii – starfish
Coelopleurus wetherelli, Micraster sp. and Schizaster sp. – sea urchins
Democrinus londinensis – crinoid
?Ophiacantha sp., Ophioglypha wetherelli, Ophiomusium sp. and Ophiura wetherelli – brittlestars
Annelids
Rotularia bognoriensis
Serpula trilineataCnidarians
Paracyathus brevis and P. caryophyllus – corals
Graphularia wetherelli – hydrozoan
Other invertebrates
Adenellopsis wetherelli, Aimulosia sp., Batopora clithridiata, Beisselina sp., Cribrilina sp., Didymosella sp., Dittosaria wetherelli, Entalophora sp., Idmonia sp., Lunulites sp., Nellia sp., Pachythecella incisa, Vibracellina sp. and Websteria crissioides – bryozoans
Hemiptera gen. et sp. indet. – true bug
Lingula tenuis, Terebratulina striatula and T. wardenensis – lampshells
Stelleta sp. – sponge
Ichnofossils
Ditrupa plana – polychaete worm tubes?
Scolithos''
Notes
References
London-related lists
London Clay
Paleogene United Kingdom
Paleogene life
Paleogene plants
Lists of prehistoric animals
London Clay species | Paleobiota of the London Clay | Biology | 7,769 |
17,936,319 | https://en.wikipedia.org/wiki/Prazitone | Prazitone (, ; developmental code name AGN-511) is a barbiturate derivative described as an antidepressant which was developed in the 1960s. Unlike most barbiturates, it has little or no sedative effects, instead acting as a non-sedating anxiolytic and antidepressant. The dosage range in humans is around 200–600 mg, although higher doses have been used in trials for the treatment of depression associated with Parkinson's disease.
References
Abandoned drugs
Antidepressants
Anxiolytics
Barbiturates
Piperidines
Pyrimidines | Prazitone | Chemistry | 130 |
60,728,179 | https://en.wikipedia.org/wiki/Ava%20%28company%29 | Ava is a medical technology company that developed the Ava bracelet, a wearable device that functions as a fertility tracker.
History
The company was founded in Zürich, Switzerland by Lea Von Bidder, Pascal Koenig, Philipp Tholen, and Peter Stein. In September 2015, the company took part in TechCrunch’s Startup Battlefield. In November 2015, Ava raised a $2.6 million funding round led by Swisscom and ZKB. The company began shipping the Ava bracelet to customers in July 2016. The company raised nearly $40 million in funding between 2017 and 2018.
Technology
The device is intended to allow wearers to estimate their fertile window by tracking their menstrual cycle and ovulation based on measurements of their skin temperature, heart rate, perfusion, breathing rate, and heart rate variability. Data collected from the bracelet is displayed on an app, so that the wearer can track their fertility or monitor their health during pregnancy. An independent study of the bracelet's validity found that it provided accurate assessments of sleep duration but that its estimates of other data such as heart rate were inaccurate in comparison to other monitoring methods such as actigraphy.
References
Medical technology
Fertility
Women's health | Ava (company) | Biology | 246 |
4,406,486 | https://en.wikipedia.org/wiki/Techron | Techron is a patented fuel additive developed by Chevron Corporation and sold in its fuel operations (including Texaco and Caltex). It contains a polyether amine-based detergent, which is purported to dissolve deposits in automotive engines and prevent them from building up. Chevron released Techron as an additive in 1981, and began including it in all of their gasoline products in 1995. It is still available as a concentrate today.
The Chevron Cars debuted in 1995 and were used to advertise the additive.
Components
Techron consists of five components:
Distillates, hydrotreated light at 40-70% weight
Stoddard solvent at 15-40% weight
Solvent naphtha (petroleum), light aromatic at 5-10% weight
1,2,4-trimethylbenzene at 1-5% weight
Polyetheramine (PEA) (detergent), polyether amines at 20-49% weight
Predecessor
"Techroline" was the predecessor to Techron. The company claimed it could control combustion-chamber deposits in cars, as well as keep their fuel-intake systems clean.
See also
List of automotive fuel brands
References
External links
Motor Gasolines Technical Review on Chevron website (2009)
Chevron Unveils New Gasolines With "Techron" at Chevron Press Release Archives (15 May 1995)
Chevron Techron® Concentrate Plus Fuel System Cleaner on Chevron website (archived 17 Oct 2006)
Products introduced in 1981
Products introduced in 1995
1981 establishments in the United States
Petroleum products
Polyethers
Amines
Chevron Corporation brands
Texaco
Fuel additives | Techron | Chemistry | 333 |
52,623,538 | https://en.wikipedia.org/wiki/Hexolame | Hexolame, also known as 17β-((6-hydroxyhexyl)amino)estradiol, is a synthetic, steroidal estrogen and a 17β-aminoestrogen with anticoagulant effects that was first described in 1990 and was never marketed.
References
Primary alcohols
Amines
Anticoagulants
Estranes
Synthetic estrogens | Hexolame | Chemistry | 82 |
1,249,586 | https://en.wikipedia.org/wiki/Namaste | Namaste (, Devanagari: नमस्ते), sometimes called namaskār and namaskāram, is a customary Hindu manner of respectfully greeting and honouring a person or group, used at any time of day. It is used worldwide among the Hindu, Buddhist and Jain traditions. Namaste is usually spoken with a slight bow and hands pressed together, palms touching and fingers pointing upwards, thumbs close to the chest. This gesture is called añjali mudrā; the standing posture incorporating it is pranāmāsana.
Etymology, meaning and origins
Namaste (Namas + te) is derived from Sanskrit and is a combination of the word namas and the second person dative pronoun in its enclitic form, te. The word namaḥ takes the sandhi form namas before the sound te.
It is found in the Vedic literature. Namas-krita and related terms appear in the Hindu scripture Rigveda such as in the Vivaha Sukta, verse 10.85.22 in the sense of "worship, adore", while Namaskara appears in the sense of "exclamatory adoration, homage, salutation and worship" in the Atharvaveda, the Taittiriya Samhita, and the Aitareya Brahmana. It is an expression of veneration, worship, reverence, an "offering of homage" and "adoration" in the Vedic literature and post-Vedic texts such as the Mahabharata. The phrase Namas-te appears with this meaning in Rigveda 8.75.10, Atharvaveda verse 6.13.2, Taittirya Samhita 2.6.11.2 and in numerous other instances in many early Hindu texts. It is also found in numerous ancient and medieval era sculpture and mandapa relief artwork in Hindu temples.
According to the Indologist Stephen Phillips, the terms "te and tvam" are an informal, familiar form of "you" in Sanskrit, and it is typically not used for unfamiliar adults. It is reserved for someone familiar, intimate, divine or a child. By using the dative form of tvam in the greeting Namas-te, there is an embedded secondary, metaphorical sense in the word. This is the basis of the pragmatic meaning of Namas-te, that is "salutations to the (divine) child (in your heart)", states Phillips.
In the contemporary era, namaḥ means 'bow', 'obeisance', 'reverential salutation' or 'adoration' and te means 'to you' (singular dative case of 'tvam'). Therefore, namaste literally means "bowing to you". In Hinduism, it also has a spiritual import reflecting the belief that "the divine and self (atman, Self) is same in you and me", and connotes "I bow to the divine in you". According to sociologist Holly Oxhandler, it is a Hindu term which means "the sacred in me recognizes the sacred in you".
A less common variant is used in the case of three or more people being addressed namely Namo vaḥ which is a combination of namaḥ and the enclitic second person plural pronoun vaḥ. The word namaḥ takes the sandhi form namo before the sound v. An even less common variant is used in the case of two people being addressed, namely, Namo vām, which is a combination of namaḥ and the enclitic second person dual pronoun vām.
History
Excavations at various Indus Valley Civilisation have revealed some male and female terracotta figures in namaste posture. These archaeological findings are dated to the Mature Harappan.
Anjali Mudra
The gesture of folding hands during a namaste is called the Añjali Mudrā. In addition to namaste, this mudra is one of the postures found in Indian classical dance such as Bharatanatyam, and in yoga practice. It is widely found in Indian temple reliefs and sculpture in mandapam, at entrances and iconography such as the Lingobhavamurti of Shaivism. The Anjali mudra differs from namaste by being a non-verbal gesture, while namaste can be said with or without any gesture. According to Bhaumik and Govil, the Anjali mudra and Namaskara mudra are very similar but have a subtle difference. The back of the thumbs in Anjali mudra face the chest and are perpendicular to other fingers, while the thumbs in Namaskara mudra are aligned with the other fingers.
Anjali mudra is described in Sanskrit texts such as in verse 9.127–128 of the Natya Shastra (200 BCE – 200 CE), in temple architecture texts dated after the sixth-century CE such as in verse 5.67 of the Devata murti prakarana and those on painting called the Citrasutras. The Natya Shastra, a classical Indian dance text, describes it to be a posture where the two hands are folded together in a reverential state and that this is used to pray before a deity, receive any person one reveres and also to greet friends. The Natya Shastra further states that for prayers inside a temple, the Anjali mudra should be placed near one's head or above, while meeting someone venerable it is placed in front of one's face or chin, and for friends near one's chest.
Uses
The gesture is widely used throughout the Indian subcontinent, parts of Asia and beyond where people of South and Southeast Asian origins have migrated. Namaste is used as a respectful form of greeting, acknowledging and welcoming a relative, guest or stranger. In some contexts, namaste is used by one person to express gratitude for assistance offered or given, and to thank the other person for his or her generous kindness.
Namaskara is one of the 16 upacharas (veneration practices) used inside temples or any place of formal puja (worship). Namaste in the context of deity worship, scholars conclude, has the same function as in greeting a guest or anyone else. It expresses politeness, courtesy, honor, and hospitality from one person to the other. It is used in goodbyes as well. This is sometimes expressed, in ancient Hindu scriptures such as Taittiriya Upanishad, as Atithi Devo Bhava (literally, treat the guest like a god).
Namaste is one of the six forms of pranama, and in parts of India these terms are used synonymously.
Since namaste is a non-contact form of greeting, some world leaders adopted the gesture as an alternative to hand shaking during the 2020 Coronavirus pandemic as a means to prevent the spread of the virus.
Gallery
See also
Culture of India
Pranāma
Sat Sri Akal
Gassho
Sampeah
Sembah
Wai
References
External links
The Meaning of Namaste Yoga Journal
Saying goodbye in different languages- Namaste
Modes of Greetings in Kashmiri, Indian Institute of Language Studies
Ancient Indus Valley Seal print showing Namaste/anjali mudra, CSU Chico
Bowing
Cultural conventions
Greetings
Gestures of respect
Greeting words and phrases
Greeting words and phrases of India
Greeting words and phrases of Nepal
Hand gestures
Human communication
Indian traditions
Mudras
Phrases
Parting phrases
Salutes
Traditions
Nepali words and phrases
Sanskrit words and phrases | Namaste | Biology | 1,546 |
33,365,410 | https://en.wikipedia.org/wiki/Commercial%20modular%20construction | Commercial Modular Buildings are code-compliant, non-residential structures that are 60% to 90% completed offsite in a factory-controlled environment. They are then transported or shipped to a final destination where the modules are then erected onto a concrete foundation to form a finished building. The word "modular" does not describe a building type or style; it simply describes a means of construction.
The commercial modular construction industry comprises two distinct divisions:
Permanent Modular Construction (PMC) – modular units built offsite for assembly onsite to create a permanent facility not intended to be relocated. They are comparable to buildings built strictly onsite in terms of quality, life span, and materials used for construction.
Relocatable Buildings – modular units built offsite for assembly onsite that can be partially or completely reused and relocated at future building sites.
Benefits
A primary benefit of modular construction is its fast delivery. Due to the simultaneous process of creating modules in a factory at the same time site work is occurring, modular buildings can be constructed in up to half the time as buildings built completely onsite. This allows the buildings to be occupied sooner and allows owners to see a faster return on investment.
So modular construction has the potential to shorten project design and engineering time and improve construction productivity. The installation of modular buildings is cost-effective, safe and environmentally friendly. The introduction of modular prefabricated units is not only possible in low-rise construction but also in multi-story and high-rise construction.
To save the most time and money and maximize the efficiency of the modular construction process, it must be implemented at the beginning of the design-build process.
Other advantages of modular construction are design customization and sustainability. The latter is a factor that stands out in the use of modular construction in reference to corporate social responsibility, both in relation to waste minimization, the use of renewable energy and the use of sustainable building materials (such as bamboo and recycled steel and wood) that reduce environmental pollution. Given that the construction sector is one of the planet's main carbon emitters, these are aspects that are increasingly in demand by those in charge of construction projects, as well as by architects and designers.
According to the UK group WRAP, (Waste and Resources Action Programme) up to a 90% reduction in materials can be achieved through the use of modular construction. Materials minimized include: wood pallets, shrink wrap, cardboard, plasterboard, timber, concrete, bricks, and cement.
Uses
Modular builders provide all types of building space, from small temporary units to complex, multi-story permanent buildings. The most commonly served markets are education, healthcare, general office, retail and commercial housing.
Some common industrial uses may include: Application Rooms, Laser Rooms, Equipment Enclosures, Environmental Rooms, Maintenance Rooms, or Storage and Security Rooms. Commercial applications may include Offices, Reception Areas, Conference and Meeting Rooms, Copy Centers and Mail Rooms, Shipping and Receiving Rooms, Lunch Rooms and Cafeterias, Break Rooms, Dark Rooms, Training Rooms, and Storage Rooms.
Modular Architecture
The use of modular architecture, especially in large-scale facilities such as hotels or shopping malls, allows for a high-quality building result with excellent value for money. Within modular architecture the use of building information models and the use of 3D modeling design technology makes it easy to take full advantage of the benefits of commercial modular construction. This is in addition to the automation of factory processes with the use of robotic fabrication which provides a result that is perfectly adapted to the needs and requirements of each project.
See also
References
External links
Modular Building Institute - international trade association for commercial modular construction
Construction
Modularity
Building
Buildings and structures | Commercial modular construction | Engineering | 742 |
17,910,853 | https://en.wikipedia.org/wiki/HD%205788%20and%20HD%205789 | HD 5789 and HD 5788 is a pair of stars comprising a binary star system in the northern constellation of Andromeda. Located approximately away, the primary is a hot, massive blue star with an apparent magnitude of 6.06 while the secondary is slightly smaller and cooler, with an apparent magnitude of 6.76. Both stars are main-sequence stars, meaning that they are currently fusing hydrogen into helium in their cores. As of 2016, the pair had an angular separation of along a position angle of 195°. While both have a similar proper motion and parallax, there's still no proof that the pair is gravitationally bound.
The primary component is HD 5789, a B-type main-sequence star with a stellar classification of B9.5Vnn (λ Boo), where the 'n' indicates "nebulous" lines due to rapid rotation. Abt and Morrell (1995) listed it as a Lambda Boötis star, although this is disputed. It has 2.7 times the mass of the Sun and is spinning rapidly with a projected rotational velocity of 249 km/s. The star is radiating 86 times the Sun's luminosity from its photosphere at an effective temperature of 9,977 K.
The fainter secondary component is an A-type main-sequence star with a class of A2 Vn. It shows a projected rotational velocity of 270 km/s and has 2.7 times the Sun's mass. The star shines with 73 times the Sun's luminosity at an effective temperature of 9,840 K.
References
A-type main-sequence stars
B-type main-sequence stars
Binary stars
Andromeda (constellation)
BD+43 0193
005788
004675
0282 | HD 5788 and HD 5789 | Astronomy | 372 |
14,897,936 | https://en.wikipedia.org/wiki/Adrian%20Bowyer | Adrian Bowyer is an English engineer and mathematician, formerly an academic at the University of Bath.
Life and works
Born in 1952 in London, Bowyer is the older child of the late Rosemary and John Bowyer; the latter was a writer, painter and one of the founders of Zisman, Bowyer and Partners, consulting engineers. Bowyer was educated at Woodroffe School, Lyme Regis and Imperial College London.
In 1977 he joined the Mathematics Department at the University of Bath. Shortly after that he received a doctorate from Imperial College London for research in friction-induced vibration. Whilst working in the Mathematics Department he invented (at the same time as David Watson) the algorithm for computing Voronoi diagrams that bears their names (the Bowyer–Watson algorithm).
He then spent twenty-two years as a lecturer then senior lecturer in the Mechanical Engineering Department at the University of Bath. He retired from academic life in 2012, though he is still a director of the company RepRap Ltd. He invented the RepRap Project – an open-source 3D printer that can produce plastic parts, including all such parts for a copy of itself. The Guardian said of this, "[RepRap] has been called the invention that will bring down global capitalism, start a second industrial revolution and save the environment..."
In 2017 Bowyer received the 3D Printing Industry Outstanding Contribution to 3D Printing Award and was inducted into the TCT Hall of Fame. He was appointed a Member of the Order of the British Empire (MBE) in the 2019 New Year Honours for services to 3D Printing.
His wife is a retired school teacher; they have one adult daughter.
References
External links
Adrian Bowyer's home page
RepRapLtd.com
Wealth Without Money , Adrian Bowyer at Medialab-Prado
In the future everyone will work for 15 minutes, Adrian Bowyer presentation
1952 births
Living people
Engineers from London
Academics of the University of Bath
Articles containing video clips
RepRap project
Alumni of Imperial College London
Date of birth missing (living people)
3D printing specialists
Mathematicians from London
Members of the Order of the British Empire | Adrian Bowyer | Engineering,Biology | 429 |
11,848,344 | https://en.wikipedia.org/wiki/Department%20of%20Petroleum%20Engineering%20and%20Applied%20Geophysics%2C%20NTNU | In 2017 the department was merged with the Department of Geology and Mineral Resources Engineering, forming the new
Department of Geoscience and Petroleum.
The Norwegian University of Science and Technology (NTNU) is the key university of science and technology in Norway. The Department of Petroleum Engineering and Applied Geophysics (IPT) was established in 1973, shortly after the start of production (Ekofisk field) from the Norwegian continental shelf. The department came to include Petroleum Engineering as well as Geophysics, which is seen as a major strength of the petroleum education at NTNU. The department has elected chairman and vice chairman, and 4 informal groups of professors; geophysics, drilling, production and reservoir engineering. The stated primary purpose of maintaining the informal groups is to take care of the teaching in their respective disciplines. Each group is responsible for offering a sufficient number of courses, semester projects and thesis projects at MSc and PhD levels in their discipline, and to make annual revisions of these in accordance with the needs of society and industry. The total number of professors, associate professors, assistant professors and adjunct professors is 32. The administrative staff is led by a department administrator, and consists of a total of 6 secretaries. The technical support staff reports to the department head, and consists of 8 engineers and technicians. Until 2000, the department was part of the Applied Earth Sciences faculty, together with the Geology-department. After that, the department is part of the Faculty of Engineering Science and Technology (one of a total of 10 departments).
Brief historical statistics of the department:
Established in 1973
More than 2000 graduated M.Sc.´s
More than 150 graduated Ph.D.´s
Around 120 M.Sc.´s graduate every year
Around 10 Ph.D.´s graduate every year
Currently around 120 full-time teachers, researchers and staff
Around 450 students enrolled at B.Sc. and M.Sc. levels
Around 65 PhD students enrolled
Research
The department focus research within the following 5 areas: Petroleum geophysics, Reservoir engineering, Production engineering, Subsea engineering, Drilling engineering and Integrated operations.
Petroleum Geophysics:
Marine seismic sources
Seismic tomography and imaging
Inversion for elastic parameters (AVA) and reservoir parameters
Reservoir seismic and rock physics
Analysis of repeated seismic data (four-dimensional)
Processing of marine controlled source electromagnetic data
Modelling and characterization of anisotropic layered media (seismic and EM)
Reservoir Engineering:
Experimental studies on novel methods for improved oil recovery, like chemical flooding, non-hydrocarbon gas flooding and microbial flooding
Development of improved methods for numerical simulation of enhanced oil recovery processes in conventional, fractured and heterogeneous reservoirs
Development of improved techniques for interpretation of well tests, specially related to compressible reservoirs
Development of phase-behaviour software for non-hydrocarbon injection gases for enhanced oil recovery
Production Engineering
Multiphase flow in wells and pipelines
Pumping and artificial lift
Flow assurance and condition monitoring
Hydrate for transport of natural gas
Processing of oil and gas
Field development
Subsea Engineering:
All-electric subsea control systems including electrical connectors and valve actuators
Experimental and numerical studies of near well bore formation damage related to balanced drilling
Drilling engineering:
Horizontal drilling
Electric pulse drilling
Improved drilling fluid properties
Managed pressure drilling
Integrated operations: The department hosts the Center for Integrated Operations in the Petroleum Industry. Key research areas are drilling, reservoir management, production optimization, operation and maintenance.
International
The department states that it intends to be strongly focused on the international profile with a friendly multi-cultural atmosphere. From the very beginning the international atmosphere existed at IPT in the form of teachers, researchers and students from various countries. IPT has been actively cooperating with countries like Angola, Aserbadjan, Australia, Austria, Bangladesh, Brazil, Canada, France, Germany, Italy, Iran, Mozambique, Netherlands, Russia, Spain, United States, Venezuela; altogether more than 50 countries. There are two 2-years international programs leading to Master's degrees, one in Petroleum Engineering and one in Petroleum Geoscience. Exchange students may take shorter term education within this program. In addition Ph.D-positions are open to qualified international candidates. These positions also constitute the basis for international research cooperation. Professors have individual scientific cooperation with various foreign institutions. The funding comes from Norwegian agencies SIU (NORAD, QUOTA), EnPe (NORAD, QUOTA), The Research Council of Norway, oil companies Statoil, Total, BP, and NTNU Scholarships; also from European Programs (Erasmus, Marie Curie, TIME, Socrates) and others. IPT cultivates personal international contacts as originators of new collaboration. Graduated Ph.D.s represent a particular bridging potential for new joint research.
Innovation
New companies, on average one new company each year, are founded by professors or students, including: Agir Boosting Technology, Geoprobing Technology, DeepSeaAnchors, Markland Technology, Natural Gas Hydrate, PERA, Petrostreamz, Petreco, ResLab, Corrocean, Sensorlink, Seres, Technoguide, Verande, Voxelvision, Waptheweb.
References
Norwegian University of Science and Technology
Norwegian University of Science and Technology, Petroleum
Geophysics organizations
Petroleum engineering schools
Petroleum in Norway
Educational institutions established in 1973
1973 establishments in Norway
1973 in the environment | Department of Petroleum Engineering and Applied Geophysics, NTNU | Engineering | 1,072 |
3,969,336 | https://en.wikipedia.org/wiki/The%20Neutral%20Theory%20of%20Molecular%20Evolution | The Neutral Theory of Molecular Evolution is an influential monograph written in 1983 by Japanese evolutionary biologist Motoo Kimura. While the neutral theory of molecular evolution existed since his article in 1968, Kimura felt the need to write a monograph with up-to-date information and evidences showing the importance of his theory in evolution.
Evolution is a change in the frequency of alleles in a population over time. Mutations occur at random and in the Darwinian evolution model natural selection acts on the genetic variation in a population that has arisen through this mutation. These mutations can be beneficial or deleterious and are selected for or against based on that factor. In this theory, every evolutionary event, mutation, and gene polymorphism (neutral differences in phenotype or genotype) would have to be positively or negatively selected for and show some kind of change over many generations. If these genetic differences grow between different populations speciation events can occur. When this theory was first introduced to the scientific community, there was no understanding of genetic principles such as drift or synonymous mutation.
When molecular biologists, like Motoo Kimura (1979), began to examine the DNA evidence, they found that far more mutations occur in non-protein coding regions or are synonymous mutations in coding regions (which do not change the protein structure or function) and are, therefore, not involved in selection as they do not impact an organism’s fitness. These findings began to show that the positive or negative selection in Darwinian evolution was too simplistic to describe every evolutionary process. Through various experiments Kimura was able to determine that proteins in mammalian lineages were polymorphisms of each other, having only one or two point mutations that did not affect the actions of the protein in any way, whereas in Darwinian evolution a slow pattern of selection in genetic lineages with increasing fitness through generations is expected. The molecular evidence showed that DNA changes more often than what was originally expected and no real pattern was found. Polymorphisms in proteins that have no effect to the function are neutral or nearly neutral and do not get selected for or against at all. This theory would mean that each change in DNA that is passed on to the next generation does not result in a morphological change that can be acted upon by natural selection.
Genetic drift, or the result of a limited population size, can also cause a change in allele frequencies over time that can look like Darwinian evolution while actually being an entirely random or as Kimura puts it "neutral" process. In this scenario a relatively small population can lose neutral alleles through the random deaths or migrations of individuals that have them. It may appear to an onlooker that one trait is being selected for over another but in actuality it is a neutral process that is not necessarily undergoing selection as it would in Darwinian evolution.
Neutral theory in research
Selective constraint in mammalian genes
Within the neutral theory, selective constraint is a type of negative selection that can occur in populations. When selective constraint is reached at a locus negative selection becomes so small that it is effectively neutral. This concept (also brought to prominence by Motoo Kimura (1979) in his expansion of the Neutral Theory of Molecular Evolution (1979) has been put to use in work concerning mammalian genes. In a study done by Price and Graur in 2015, the pair tried to find evidence on whether genes in primates and rodents were either undergoing Darwinian selection or were neutrally evolving under Kimura's model. The number of guanine/cytosine base pairs were utilized in pseudogenes that mimicked nonsynonymous and synonymous mutations that began at what would be expected in a truly neutrally evolving genome for both rodents and primates. Their findings showed that in rodents, the pseudogenes were evolving as one would expect under neutral conditions whereas in primates purifying selection was having an effect on as many as 20% of the pseudogenes tested. By these estimates in primates, 20-40% of their genes could be under selective constraint in the neutral model.
Content
From Lamarck to population genetics
Overdevelopment of the synthetic theory and the proposal of the neutral theory
The neutral mutation-random drift hypothesis as an evolutionary paradigm
Molecular evolutionary rates contrasted with phenotypic evolutionary rates
Some features of molecular evolution
Definition, types and action of natural selection
Molecular structure, selective constraint and the rate of evolution
Population genetics at the molecular level
Summary and conclusion
See also
Molecular evolution
Molecular clock
Population genetics
References
Further reading
External links
Review of the book by Gert Korthof
Books about evolution
1983 non-fiction books
1983 in science
Molecular evolution
Population genetics
Neutral theory | The Neutral Theory of Molecular Evolution | Chemistry,Biology | 939 |
1,313 | https://en.wikipedia.org/wiki/Aromatic%20compound | Aromatic compounds or arenes are organic compounds "with a chemistry typified by benzene" and "cyclically conjugated."
The word "aromatic" originates from the past grouping of molecules based on odor, before their general chemical properties were understood. The current definition of aromatic compounds does not have any relation to their odor. Aromatic compounds are now defined as cyclic compounds satisfying Hückel's Rule.
Aromatic compounds have the following general properties:
Typically unreactive
Often non polar and hydrophobic
High carbon-hydrogen ratio
Burn with a strong sooty yellow flame, due to high C:H ratio
Undergo electrophilic substitution reactions and nucleophilic aromatic substitutions
Arenes are typically split into two categories - benzoids, that contain a benzene derivative and follow the benzene ring model, and non-benzoids that contain other aromatic cyclic derivatives. Aromatic compounds are commonly used in organic synthesis and are involved in many reaction types, following both additions and removals, as well as saturation and dearomatization.
Heteroarenes
Heteroarenes are aromatic compounds, where at least one methine or vinylene (-C= or -CH=CH-) group is replaced by a heteroatom: oxygen, nitrogen, or sulfur. Examples of non-benzene compounds with aromatic properties are furan, a heterocyclic compound with a five-membered ring that includes a single oxygen atom, and pyridine, a heterocyclic compound with a six-membered ring containing one nitrogen atom. Hydrocarbons without an aromatic ring are called aliphatic. Approximately half of compounds known in 2000 are described as aromatic to some extent.
Applications
Aromatic compounds are pervasive in nature and industry. Key industrial aromatic hydrocarbons are benzene, toluene, xylene called BTX. Many biomolecules have phenyl groups including the so-called aromatic amino acids.
Benzene ring model
Benzene, C6H6, is the least complex aromatic hydrocarbon, and it was the first one defined as such. Its bonding nature was first recognized independently by Joseph Loschmidt and August Kekulé in the 19th century. Each carbon atom in the hexagonal cycle has four electrons to share. One electron forms a sigma bond with the hydrogen atom, and one is used in covalently bonding to each of the two neighboring carbons. This leaves six electrons, shared equally around the ring in delocalized pi molecular orbitals the size of the ring itself. This represents the equivalent nature of the six carbon-carbon bonds all of bond order 1.5. This equivalency can also explained by resonance forms. The electrons are visualized as floating above and below the ring, with the electromagnetic fields they generate acting to keep the ring flat.
The circle symbol for aromaticity was introduced by Sir Robert Robinson and his student James Armit in 1925 and popularized starting in 1959 by the Morrison & Boyd textbook on organic chemistry. The proper use of the symbol is debated: some publications use it to any cyclic π system, while others use it only for those π systems that obey Hückel's rule. Some argue that, in order to stay in line with Robinson's originally intended proposal, the use of the circle symbol should be limited to monocyclic 6 π-electron systems. In this way the circle symbol for a six-center six-electron bond can be compared to the Y symbol for a three-center two-electron bond.
Benzene and derivatives of benzene
Benzene derivatives have from one to six substituents attached to the central benzene core. Examples of benzene compounds with just one substituent are phenol, which carries a hydroxyl group, and toluene with a methyl group. When there is more than one substituent present on the ring, their spatial relationship becomes important for which the arene substitution patterns ortho, meta, and para are devised. When reacting to form more complex benzene derivatives, the substituents on a benzene ring can be described as either activated or deactivated, which are electron donating and electron withdrawing respectively. Activators are known as ortho-para directors, and deactivators are known as meta directors. Upon reacting, substituents will be added at the ortho, para or meta positions, depending on the directivity of the current substituents to make more complex benzene derivatives, often with several isomers. Electron flow leading to re-aromatization is key in ensuring the stability of such products.
For example, three isomers exist for cresol because the methyl group and the hydroxyl group (both ortho para directors) can be placed next to each other (ortho), one position removed from each other (meta), or two positions removed from each other (para). Given that both the methyl and hydroxyl group are ortho-para directors, the ortho and para isomers are typically favoured. Xylenol has two methyl groups in addition to the hydroxyl group, and, for this structure, 6 isomers exist.
Arene rings can stabilize charges, as seen in, for example, phenol (C6H5–OH), which is acidic at the hydroxyl (OH), as charge on the oxygen (alkoxide –O−) is partially delocalized into the benzene ring.
Non-benzylic arenes
Although benzylic arenes are common, non-benzylic compounds are also exceedingly important. Any compound containing a cyclic portion that conforms to Hückel's rule and is not a benzene derivative can be considered a non-benzylic aromatic compound.
Monocyclic arenes
Of annulenes larger than benzene, [12]annulene and [14]annulene are weakly aromatic compounds and [18]annulene, Cyclooctadecanonaene, is aromatic, though strain within the structure causes a slight deviation from the precisely planar structure necessary for aromatic categorization. Another example of a non-benzylic monocyclic arene is the cyclopropenyl (cyclopropenium cation), which satisfies Hückel's rule with an n equal to 0. Note, only the cationic form of this cyclic propenyl is aromatic, given that neutrality in this compound would violate either the octet rule or Hückel's rule.
Other non-benzylic monocyclic arenes include the aforementioned heteroarenes that can replace carbon atoms with other heteroatoms such as N, O or S. Common examples of these are the six-membered pyrrole and five-membered pyridine, both of which have a substituted nitrogen
Polycyclic aromatic hydrocarbons
Polycyclic aromatic hydrocarbons, also known as polynuclear aromatic compounds (PAHs) are aromatic hydrocarbons that consist of fused aromatic rings and do not contain heteroatoms or carry substituents. Naphthalene is the simplest example of a PAH. PAHs occur in oil, coal, and tar deposits, and are produced as byproducts of fuel burning (whether fossil fuel or biomass). As pollutants, they are of concern because some compounds have been identified as carcinogenic, mutagenic, and teratogenic. PAHs are also found in cooked foods. Studies have shown that high levels of PAHs are found, for example, in meat cooked at high temperatures such as grilling or barbecuing, and in smoked fish. They are also a good candidate molecule to act as a basis for the earliest forms of life. In graphene the PAH motif is extended to large 2D sheets.
Reactions
Aromatic ring systems participate in many organic reactions.
Substitution
In aromatic substitution, one substituent on the arene ring, usually hydrogen, is replaced by another reagent. The two main types are electrophilic aromatic substitution, when the active reagent is an electrophile, and nucleophilic aromatic substitution, when the reagent is a nucleophile. In radical-nucleophilic aromatic substitution, the active reagent is a radical.
An example of electrophilic aromatic substitution is the nitration of salicylic acid, where a nitro group is added para to the hydroxide substituent:
Nucleophilic aromatic substitution involves displacement of a leaving group, such as a halide, on an aromatic ring. Aromatic rings usually nucleophilic, but in the presence of electron-withdrawing groups aromatic compounds undergo nucleophilic substitution. Mechanistically, this reaction differs from a common SN2 reaction, because it occurs at a trigonal carbon atom (sp2 hybridization).
Hydrogenation
Hydrogenation of arenes create saturated rings. The compound 1-naphthol is completely reduced to a mixture of decalin-ol isomers.
The compound resorcinol, hydrogenated with Raney nickel in presence of aqueous sodium hydroxide forms an enolate which is alkylated with methyl iodide to 2-methyl-1,3-cyclohexandione:
Dearomatization
In dearomatization reactions the aromaticity of the reactant is lost. In this regard, the dearomatization is related to hydrogenation. A classic approach is Birch reduction. The methodology is used in synthesis.
See also
Aromatic substituents: Aryl, Aryloxy and Arenediyl
Asphaltene
Hydrodealkylation
Simple aromatic rings
Rhodium-platinum oxide, a catalyst used to hydrogenate aromatic compounds.
References
External links | Aromatic compound | Chemistry | 2,045 |
20,872,694 | https://en.wikipedia.org/wiki/Coordinate%20conditions | In general relativity, the laws of physics can be expressed in a generally covariant form. In other words, the description of the world as given by the laws of physics does not depend on our choice of coordinate systems. However, it is often useful to fix upon a particular coordinate system, in order to solve actual problems or make actual predictions. A coordinate condition selects such coordinate system(s).
Indeterminacy in general relativity
The Einstein field equations do not determine the metric uniquely, even if one knows what the metric tensor equals everywhere at an initial time. This situation is analogous to the failure of the Maxwell equations to determine the potentials uniquely. In both cases, the ambiguity can be removed by gauge fixing. Thus, coordinate conditions are a type of gauge condition. No coordinate condition is generally covariant, but many coordinate conditions are Lorentz covariant or rotationally covariant.
Naively, one might think that coordinate conditions would take the form of equations for the evolution of the four coordinates, and indeed in some cases (e.g. the harmonic coordinate condition) they can be put in that form. However, it is more usual for them to appear as four additional equations (beyond the Einstein field equations) for the evolution of the metric tensor. The Einstein field equations alone do not fully determine the evolution of the metric relative to the coordinate system. It might seem that they would since there are ten equations to determine the ten components of the metric. However, due to the second Bianchi identity of the Riemann curvature tensor, the divergence of the Einstein tensor is zero which means that four of the ten equations are redundant, leaving four degrees of freedom which can be associated with the choice of the four coordinates. The same result can be derived from a Kramers-Moyal-van-Kampen expansion of the Master equation (using the Clebsch–Gordan coefficients for decomposing tensor products).
Harmonic coordinates
A particularly useful coordinate condition is the harmonic condition (also known as the "de Donder gauge"):
Here, gamma is a Christoffel symbol (also known as the "affine connection"), and the "g" with superscripts is the inverse of the metric tensor. This harmonic condition is frequently used by physicists when working with gravitational waves. This condition is also frequently used to derive the post-Newtonian approximation.
Although the harmonic coordinate condition is not generally covariant, it is Lorentz covariant. This coordinate condition resolves the ambiguity of the metric tensor by providing four additional differential equations that the metric tensor must satisfy.
Synchronous coordinates
Another particularly useful coordinate condition is the synchronous condition:
and
.
Synchronous coordinates are also known as Gaussian coordinates. They are frequently used in cosmology.
The synchronous coordinate condition is neither generally covariant nor Lorentz covariant. This coordinate condition resolves the ambiguity of the metric tensor by providing four algebraic equations that the metric tensor must satisfy.
Other coordinates
Many other coordinate conditions have been employed by physicists, though none as pervasively as those described above. Almost all coordinate conditions used by physicists, including the harmonic and synchronous coordinate conditions, would be satisfied by a metric tensor that equals the Minkowski tensor everywhere. (However, since the Riemann and hence the Ricci tensor for Minkowski coordinates is identically zero, the Einstein equations give zero energy/matter for Minkowski coordinates; so Minkowski coordinates cannot be an acceptable final answer.) Unlike the harmonic and synchronous coordinate conditions, some commonly used coordinate conditions may be either under-determinative or over-determinative.
An example of an under-determinative condition is the algebraic statement that the determinant of the metric tensor is −1, which still leaves considerable gauge freedom. This condition would have to be supplemented by other conditions in order to remove the ambiguity in the metric tensor.
An example of an over-determinative condition is the algebraic statement that the difference between the metric tensor and the Minkowski tensor is simply a null four-vector times itself, which is known as a Kerr-Schild form of the metric. This Kerr-Schild condition goes well beyond removing coordinate ambiguity, and thus also prescribes a type of physical space-time structure. The determinant of the metric tensor in a Kerr-Schild metric is negative one, which by itself is an under-determinative coordinate condition.
When choosing coordinate conditions, it is important to beware of illusions or artifacts that can be created by that choice. For example, the Schwarzschild metric may include an apparent singularity at a surface that is separate from the point-source, but that singularity is merely an artifact of the choice of coordinate conditions, rather than arising from actual physical reality.
If one is going to solve the Einstein field equations using approximate methods such as the post-Newtonian expansion, then one should try to choose a coordinate condition which will make the expansion converge as quickly as possible (or at least prevent it from diverging). Similarly, for numerical methods one needs to avoid caustics (coordinate singularities).
Lorentz covariant coordinate conditions
If one combines a coordinate condition which is Lorentz covariant, such as the harmonic coordinate condition mentioned above, with the Einstein field equations, then one gets a theory which is in some sense consistent with both special and general relativity. Among the simplest examples of such coordinate conditions are these:
where one can fix the constant k to be any convenient value.
Footnotes
Coordinate charts in general relativity | Coordinate conditions | Mathematics | 1,159 |
3,928,533 | https://en.wikipedia.org/wiki/Spherical%20law%20of%20cosines | In spherical trigonometry, the law of cosines (also called the cosine rule for sides) is a theorem relating the sides and angles of spherical triangles, analogous to the ordinary law of cosines from plane trigonometry.
Given a unit sphere, a "spherical triangle" on the surface of the sphere is defined by the great circles connecting three points , and on the sphere (shown at right). If the lengths of these three sides are (from to (from to ), and (from to ), and the angle of the corner opposite is , then the (first) spherical law of cosines states:
Since this is a unit sphere, the lengths , and are simply equal to the angles (in radians) subtended by those sides from the center of the sphere. (For a non-unit sphere, the lengths are the subtended angles times the radius, and the formula still holds if and are reinterpreted as the subtended angles). As a special case, for , then , and one obtains the spherical analogue of the Pythagorean theorem:
If the law of cosines is used to solve for , the necessity of inverting the cosine magnifies rounding errors when is small. In this case, the alternative formulation of the law of haversines is preferable.
A variation on the law of cosines, the second spherical law of cosines, (also called the cosine rule for angles) states:
where and are the angles of the corners opposite to sides and , respectively. It can be obtained from consideration of a spherical triangle dual to the given one.
Proofs
First proof
Let , and denote the unit vectors from the center of the sphere to those corners of the triangle. The angles and distances do not change if the coordinate system is rotated, so we can rotate the coordinate system so that is at the north pole and is somewhere on the prime meridian (longitude of 0). With this rotation, the spherical coordinates for are where is the angle measured from the north pole not from the equator, and the spherical coordinates for are The Cartesian coordinates for are and the Cartesian coordinates for are The value of is the dot product of the two Cartesian vectors, which is
Second proof
Let , and denote the unit vectors from the center of the sphere to those corners of the triangle. We have , , , and . The vectors and have lengths and respectively and the angle between them is , so
using cross products, dot products, and the Binet–Cauchy identity
Third proof
The following proof relies on the concept of quaternions and is based on a proof given in Brand: Let , , and denote the unit vectors from the center of the unit sphere to those corners of the triangle. We define the quaternion . The quaternion is used to represent a rotation by 180° around the axis indicated by the vector . We note that using as the axis of rotation gives the same result, and that the rotation is its own inverse. We also define and .
We compute the product of quaternions, which also gives the composition of the corresponding rotations:
where represents the real and imaginary parts of a quaternion, is the angle between and , and is the axis of the rotation that moves to along a great circle. Similarly we define:
.
The quaternions , , and are used to represent rotations with axes of rotation , , and , respectively, and angles of rotation , , and , respectively. Because these are double angles, each of , , and represents two applications of the rotation implied by an edge of the spherical triangle.
From the definitions, it follows that
,
which tells us that the composition of these rotations is the identity transformation. In particular, gives us
.
Expanding the left-hand side, we obtain
Equating the scalar parts on both sides of the identity, we obtain
Because is parallel to , is parallel to , and is the angle between and , it follows that . Thus,
Rearrangements
The first and second spherical laws of cosines can be rearranged to put the sides () and angles () on opposite sides of the equations:
Planar limit: small angles
For small spherical triangles, i.e. for small , and , the spherical law of cosines is approximately the same as the ordinary planar law of cosines,
To prove this, we will use the small-angle approximation obtained from the Maclaurin series for the cosine and sine functions:
Substituting these expressions into the spherical law of cosines nets:
or after simplifying:
The big O terms for and are dominated by as and get small, so we can write this last expression as:
History
Something equivalent to the spherical law of cosines was used (but not stated in general) by al-Khwārizmī (9th century), al-Battānī (9th century), and Nīlakaṇṭha (15th century).
See also
Half-side formula
Hyperbolic law of cosines
Solution of triangles
Spherical law of sines
Notes
Spherical trigonometry
Articles containing proofs
Theorems in geometry
he:טריגונומטריה ספירית#משפט הקוסינוסים | Spherical law of cosines | Mathematics | 1,103 |
58,037,076 | https://en.wikipedia.org/wiki/Kernel-phase | Kernel-phases are observable quantities used in high resolution astronomical imaging used for superresolution image creation. It can be seen as a generalization of closure phases for redundant arrays. For this reason, when the wavefront quality requirement are met, it is an alternative to aperture masking interferometry that can be executed without a mask while retaining phase error rejection properties. The observables are computed through linear algebra from the Fourier transform of direct images. They can then be used for statistical testing, model fitting, or image reconstruction.
Prerequisites
In order to extract kernel-phases from an image, some requirements must be met:
Images are nyquist-sampled (at least 2 pixels per resolution element ())
Images are taken in near monochromatic light
Exposure time is shorter than the timescale of aberrations
Strehl ratio is high (good adaptive optics)
Linearity of the pixel response (i.e. no saturation)
Deviations from these requirements are known to be acceptable, but lead to observational bias that should be corrected by the observation of calibrators.
Definition
The method relies on a discrete model of the instrument's pupil plane and the corresponding list of baselines to provide corresponding vectors of pupil plane errors and of image plane Fourier Phases. When the wavefront error in the pupil plane is small enough (i.e. when the Strehl ratio of the imaging system is sufficiently high), the complex amplitude associated to the instrumental phase in one point of the pupil , can be approximated by . This permits the expression of the pupil-plane phase aberrations to the image plane Fourier phase as a linear transformation described by the matrix :
Where is the theoretical Fourier phase vector of the object. In this formalism, singular value decomposition can be used to find a matrix satisfying . The rows of constitute a basis of the kernel of .
The vector is called the kernel-phase vector of observables. This equation can be used for model-fitting as it represents the interpretation of a sub-space of the Fourier phase that is immune to the instrumental phase errors to the first order.
Applications
The technique was first used in the re-analysis of archival images from the Hubble Space Telescope where it enabled the discovery of a number of brown dwarf in close binary systems.
The technique is used as an alternative to aperture masking interferometry, especially for fainter stars because it does not require the use of masks that typically block 90% of the light, and therefore allows higher throughput. It is also considered to be an alternative to coronagraphy for direct detection of exoplanets at very small separations (below ) where coronagraphs are limited by the wavefront errors of adaptive optics.
The same framework can be used for wavefront sensing. In the case of an asymmetric aperture, a pseudo-inverse of can be used to reconstruct the wavefront errors directly from the image.
A Python library called xara is available on GitHub and maintained by Frantz Martinache to facilitate the extraction and interpretation of kernel-phases.
The KERNEL project, has received funding from the European Research Council to explore the potential of these observables for a number of use-cases, including direct detection of exoplanets, image reconstruction, and image plane wavefront sensing for adaptive optics.
References
Astronomical imaging
Astronomical interferometers
Image processing
Signal processing | Kernel-phase | Astronomy,Technology,Engineering | 696 |
75,290,411 | https://en.wikipedia.org/wiki/Prospekta | Prospekta is a nootropic drug reported to act on the S100 proteins. It was developed by the company Materia Medica and approved in Russia for the treatment of ADHD in 2022. It was also studied for vascular dementia.
References
Nootropics | Prospekta | Chemistry | 59 |
42,069,780 | https://en.wikipedia.org/wiki/Affine%20monoid | In abstract algebra, a branch of mathematics, an affine monoid is a commutative monoid that is finitely generated, and is isomorphic to a submonoid of a free abelian group . Affine monoids are closely connected to convex polyhedra, and their associated algebras are of much use in the algebraic study of these geometric objects.
Characterization
Affine monoids are finitely generated. This means for a monoid , there exists such that
.
Affine monoids are cancellative. In other words,
implies that for all , where denotes the binary operation on the affine monoid .
Affine monoids are also torsion free. For an affine monoid , implies that for , and .
A subset of a monoid that is itself a monoid with respect to the operation on is a submonoid of .
Properties and examples
Every submonoid of is finitely generated. Hence, every submonoid of is affine.
The submonoid of is not finitely generated, and therefore not affine.
The intersection of two affine monoids is an affine monoid.
Affine monoids
Group of differences
If is an affine monoid, it can be embedded into a group. More specifically, there is a unique group , called the group of differences, in which can be embedded.
Definition
can be viewed as the set of equivalences classes , where if and only if , for , and
defines the addition.
The rank of an affine monoid is the rank of a group of .
If an affine monoid is given as a submonoid of , then , where is the subgroup of .
Universal property
If is an affine monoid, then the monoid homomorphism defined by satisfies the following universal property:
for any monoid homomorphism , where is a group, there is a unique group homomorphism , such that , and since affine monoids are cancellative, it follows that is an embedding. In other words, every affine monoid can be embedded into a group.
Normal affine monoids
Definition
If is a submonoid of an affine monoid , then the submonoid
is the integral closure of in . If , then is integrally closed.
The normalization of an affine monoid is the integral closure of in . If the normalization of , is itself, then is a normal affine monoid.
A monoid is a normal affine monoid if and only if is finitely generated and .
Affine monoid rings
see also: Group ring
Definition
Let be an affine monoid, and a commutative ring. Then one can form the affine monoid ring . This is an -module with a free basis , so if , then
, where , and .
In other words, is the set of finite sums of elements of with coefficients in .
Connection to convex geometry
Affine monoids arise naturally from convex polyhedra, convex cones, and their associated discrete structures.
Let be a rational convex cone in , and let be a lattice in . Then is an affine monoid. (Lemma 2.9, Gordan's lemma)
If is a submonoid of , then is a cone if and only if is an affine monoid.
If is a submonoid of , and is a cone generated by the elements of , then is an affine monoid.
Let in be a rational polyhedron, the recession cone of , and a lattice in . Then is a finitely generated module over the affine monoid . (Theorem 2.12)
See also
Monoid
Convex cone
Convex polytope
Lattice (group)
K-theory
References
Algebraic structures | Affine monoid | Mathematics | 758 |
25,242,181 | https://en.wikipedia.org/wiki/Lunatic%20asylum | The lunatic asylum, insane asylum or mental asylum was an institution where people with mental illness were confined. It was an early precursor of the modern psychiatric hospital.
Modern psychiatric hospitals evolved from and eventually replaced the older lunatic asylum. The treatment of inmates in early lunatic asylums was sometimes brutal and focused on containment and restraint. The discovery of anti-psychotic drugs and mood-stabilizing drugs resulted in a shift in focus from containment in lunatic asylums to treatment in psychiatric hospitals. Later, there was further and more thorough critique in the form of the deinstitutionalization movement which focuses on treatment at home or in less isolated institutions.
History
Medieval era
In the Islamic world, the Bimaristans were described by European travellers, who wrote about their wonder at the care and kindness shown to lunatics. In 872, Ahmad ibn Tulun built a hospital in Cairo that provided care to the insane, which included music therapy. Nonetheless, British historian of medicine Roy Porter cautioned against idealising the role of hospitals generally in medieval Islam, stating that "They were a drop in the ocean for the vast population that they had to serve, and their true function lay in highlighting ideals of compassion and bringing together the activities of the medical profession."
In Europe during the medieval era, a small subsection of the population of those considered mad were housed in a variety of institutional settings. Mentally ill people were often held captive in cages or kept up within the city walls, or they were compelled to amuse members of courtly society. Porter gives examples of such locales where some of the insane were cared for, such as in monasteries. A few towns had towers where madmen were kept (called Narrentürme in German, or "fools' towers"). The ancient Parisian hospital Hôtel-Dieu also had a small number of cells set aside for lunatics, whilst the town of Elbing boasted a madhouse, the Tollhaus, attached to the Teutonic Knights' hospital. Dave Sheppard's Development of Mental Health Law and Practice begins in 1285 with a case that linked "the instigation of the devil" with being "frantic and mad".
In Spain, other such institutions for the insane were established after the Christian Reconquista; facilities included hospitals in Valencia (1407), Zaragoza (1425), Seville (1436), Barcelona (1481) and Toledo (1483). In London, England, the Priory of Saint Mary of Bethlehem, which later became known more notoriously as Bedlam, was founded in 1247. At the start of the 15thcentury, it housed six insane men. The former lunatic asylum, Het Dolhuys, established in the 16thcentury in Haarlem, the Netherlands, has been adapted as a museum of psychiatry, with an overview of treatments from the origins of the building up to the 1990s.
Emergence of public lunatic asylums
The level of specialist institutional provision for the care and control of the insane remained extremely limited at the turn of the 18thcentury. Madness was seen principally as a domestic problem, with families and parish authorities in Europe and England central to regimens of care. Various forms of outdoor relief were extended by the parish authorities to families in these circumstances, including financial support, the provision of parish nurses and, where family care was not possible, lunatics might be 'boarded out' to other members of the local community or committed to private madhouses. Exceptionally, if those deemed mad were judged to be particularly disturbing or violent, parish authorities might meet the not inconsiderable costs of their confinement in charitable asylums such as Bethlem, in Houses of Correction or in workhouses.
In the late 17thcentury, this model began to change, and privately run asylums for the insane began to proliferate and expand in size. Already in 1632 it was recorded that Bethlem Royal Hospital, London had "below stairs a parlor, a kitchen, two larders, a long entry throughout the house, and 21 rooms wherein the poor distracted people lie, and above the stairs eight rooms more for servants and the poor to lie in". Inmates who were deemed dangerous or disturbing were chained, but Bethlem was an otherwise open building. Its inhabitants could roam around its confines and possibly throughout the general neighborhood in which the hospital was situated. In 1676, Bethlem expanded into newly built premises at Moorfields with a capacity for 100 inmates.
A second public charitable institution was opened in 1713. Known as the Bethel in Norwich, it was a small facility which generally housed between twenty and thirty inmates. In 1728 at Guy's Hospital, London, wards were established for chronic lunatics. From the mid-eighteenth century the number of public charitably funded asylums expanded moderately with the opening of St Luke's Hospital in 1751 in Upper Moorfields, London; the establishment in 1765 of the Hospital for Lunatics at Newcastle upon Tyne; the Manchester Lunatic Hospital, which opened in 1766; the York Asylum in 1777 (not to be confused with the York Retreat); the Leicester Lunatic Asylum (1794), and the Liverpool Lunatic Asylum (1797).
A similar expansion took place in the British American colonies. The Pennsylvania Hospital was founded in Philadelphia in 1751 as a result of work begun in 1709 by the Religious Society of Friends. A portion of this hospital was set apart for the mentally ill, and the first patients were admitted in 1752. Virginia is recognized as the first state to establish an institution for the mentally ill. Eastern State Hospital, located in Williamsburg, Virginia, was incorporated in 1768 under the name of the "Public Hospital for Persons of Insane and Disordered Minds" and its first patients were admitted in 1773.
Trade in lunacy
There was no centralised state response to “madness” in society in century Britain until the 19thcentury, however private madhouses proliferated there in the 18thcentury on a scale unseen elsewhere. References to such institutions are limited for the 17thcentury but it is evident that by the start of the 18thcentury, the so-called 'trade in lunacy' was well established. Daniel Defoe, an ardent critic of private madhouses, estimated in 1724 that there were fifteen then operating in the London area. Defoe may have exaggerated but exact figures for private metropolitan madhouses are available only from 1774, when licensing legislation was introduced: sixteen institutions were recorded. At least two of these, Hoxton House and Wood's Close, Clerkenwell, had been in operation since the 17thcentury. By 1807, the number had increased to seventeen. This limited growth in the number of London madhouses is believed likely to reflect the fact that vested interests, especially the College of Physicians, exercised considerable control in preventing new entrants to the market. Thus, rather than there being a proliferation of private madhouses in London, existing institutions tended to expand considerably in size. The establishments which increased most during the 18thcentury, such as Hoxton House, did so by accepting pauper patients rather than private, middle class, fee-paying patients. Significantly, pauper patients, unlike their private counterparts, were not subject to inspection under the 1774 legislation.
Fragmentary evidence indicates that some provincial madhouses existed in Britain from at least the 17thcentury and possibly earlier. A madhouse at Kingsdown, Box, Wiltshire was opened during the 17thcentury. Further locales of early businesses include one at Guildford in Surrey which was accepting patients by 1700, one at Fonthill Gifford in Wiltshire from 1718, another at Hook Norton in Oxfordshire from about 1725, one at St Albans dating from around 1740, and a madhouse at Fishponds in Bristol from 1766. It is likely that many of these provincial madhouses, as was the case with the exclusive Ticehurst House, may have evolved from householders who were boarding lunatics on behalf of parochial authorities and later formalised this practice into a business venture. The vast majority were small in scale with only seven asylums outside London with in excess of thirty patients by 1800 and somewhere between ten and twenty institutions had fewer patients than this.
Humanitarian reform
During the Age of Enlightenment, attitudes began to change, in particular among the educated classes in Western Europe. “Mental illness” came to be viewed as a disorder that required some form of compassionate but clinical, “rational” treatment that would aid in the rehabilitation of the patient into a rational being. When the ruling monarch of the United Kingdom, George III, who had a mental disorder, experienced a remission in 1789, mental illness came to be seen as something which could be treated and cured. The introduction of moral treatment was initiated independently by the French doctor Philippe Pinel and the English Quaker William Tuke.
In 1792, Pinel became the chief physician at the Bicêtre Hospital in Le Kremlin-Bicêtre, near Paris. Before his arrival, inmates were chained in cramped cell-like rooms where there was poor ventilation, led by a man named Jackson 'Brutis' Taylor. Taylor was then killed by the inmates leading to Pinel's leadership. In 1797, Jean-Baptiste Pussin, the "governor" of mental patients at Bicêtre, first freed patients of their chains and banned physical punishment, although straitjackets could be used instead. Patients were allowed to move freely about the hospital grounds, and eventually dark dungeons were replaced with sunny, well-ventilated rooms. Pinel argued that mental illness was the result of excessive exposure to social and psychological stresses, to heredity and physiological damage.
Pussin and Pinel's approach was seen as remarkably successful, and they later brought similar reforms to a mental hospital in Paris for female patients, La Salpetrière. Pinel's student and successor, Jean Esquirol, went on to help establish 10 new mental hospitals that operated on the same principles. There was an emphasis on the selection and supervision of attendants in order to establish a suitable setting to facilitate psychological work, and particularly on the employment of ex-patients as they were thought most likely to refrain from inhumane treatment while being able to stand up to patients' pleas, menaces, or complaints.
William Tuke led the development of a radical new type of institution in Northern England, following the death of a fellow Quaker in a local asylum in 1790. In 1796, with the help of fellow Quakers and others, he founded the York Retreat, where eventually about 30 patients lived as part of a small community in a quiet country house and engaged in a combination of rest, talk, and manual work. Rejecting medical theories and techniques, the efforts of the York Retreat centred around minimising restraints and cultivating rationality and moral strength.
The entire Tuke family became known as founders of moral treatment. They created a family-style ethos, and patients performed chores to give them a sense of contribution. There was a daily routine of both work and leisure time. If patients behaved well, they were rewarded; if they behaved poorly, there was some minimal use of restraints or instilling of fear. The patients were told that treatment depended on their conduct. In this sense, the patient's moral autonomy was recognised. William Tuke's grandson, Samuel Tuke, published an influential work in the early 19thcentury on the methods of the retreat; Pinel's Treatise on Insanity had by then been published, and Samuel Tuke translated his term as "moral treatment". Tuke's Retreat became a model throughout the world for humane and moral treatment of patients with mental disorders.
The York Retreat inspired similar institutions in the United States, most notably the Brattleboro Retreat and the Hartford Retreat (now the Institute of Living). Benjamin Rush of Philadelphia also promoted humane treatment of the insane outside dungeons and without iron restraints, as well as sought their reintegration into society. In 1792, Rush successfully campaigned for a separate ward for the insane at the Pennsylvania Hospital. His talk-based approach could be considered as a rudimentary form of modern occupational therapy, although most of his physical approaches have long been discredited, such as bleeding and purging, hot and cold baths, mercury pills, a "tranquilizing chair" and gyroscope.
A similar reform was carried out in Italy by Vincenzo Chiarugi, who discontinued the use of chains on the inmates in the early 19thcentury. In the town of Interlaken, Johann Jakob Guggenbühl started a retreat for mentally disabled children in 1841.
Institutionalisation
The modern era of institutionalized provision for the care of the mentally ill, began in the early 19thcentury with a large state-led effort. Public mental asylums were established in Britain after the passing of the 1808 County Asylums Act. This empowered magistrates to build rate-supported asylums in every county to house the many 'pauper lunatics'. Nine counties first applied, and the first public asylum opened in 1811 in Nottinghamshire. Parliamentary Committees were established to investigate abuses at private madhouses like Bethlem Hospital – its officers were eventually dismissed and national attention was focused on the routine use of bars, chains and handcuffs and the filthy conditions the inmates lived in. However, it was not until 1828 that the newly appointed Commissioners in Lunacy were empowered to license and supervise private asylums.
The Lunacy Act 1845 was an important landmark in the treatment of the mentally ill, as it explicitly changed the status of mentally ill people to patients who required treatment. The Act created the Lunacy Commission, headed by Lord Shaftesbury, to focus on lunacy legislation reform. The commission was made up of eleven Metropolitan Commissioners who were required to carry out the provisions of the Act: the compulsory construction of asylums in every county, with regular inspections on behalf of the Home Secretary. All asylums were required to have written regulations and to have a resident qualified physician. A national body for asylum superintendents – the Medico-Psychological Association – was established in 1866 under the Presidency of William A. F. Browne, although the body appeared in an earlier form in 1841.
In 1838, France enacted a law to regulate both the admissions into asylums and asylum services across the country. Édouard Séguin developed a systematic approach for training individuals with mental deficiencies, and, in 1839, he opened the first school for the "severely retarded". His method of treatment was based on the assumption that the "mentally deficient" did not suffer from disease.
In the United States, the erection of state asylums began with the first law for the creation of one in New York, passed in 1842. The Utica State Hospital was opened approximately in 1850. The creation of this hospital, as of many others, was largely the work of Dorothea Lynde Dix, whose philanthropic efforts extended over many states, and in Europe as far as Constantinople. Many state hospitals in the United States were built in the 1850s and 1860s on the Kirkbride Plan, an architectural style meant to have curative effect.
Looking into the late 19thand early 20thcentury history of the Homewood Retreat of Guelph, Ontario, and the context of commitments to asylums in North America and Great Britain, Cheryl Krasnick Warsh states that "the kin of asylum patients were, in fact, the major impetus behind commitment, but their motivations were based not so much upon greed as upon the internal dynamics of the family, and upon the economic structure of western society in the 19th and early 20thcenturies."
Women in psychiatric institutions
Based on her study of cases from the Homewood Retreat, Cheryl Krasnick Warsh concludes that "the realities of the household in late Victorian and Edwardian middle class society rendered certain elements—socially redundant women in particular—more susceptible to institutionalization than others."
In the 18th to the early 20thcentury, women were sometimes institutionalised due to their opinions, their unruliness and their inability to be controlled properly by a primarily male-dominated culture. There were financial incentives too; before the passage of the Married Women's Property Act 1882, all of a wife's assets passed automatically to her husband.
The men who were in charge of these women, either a husband, father or brother, could send these women to mental institutions, stating that they believed that these women were mentally ill because of their strong opinions. "Between the years of 1850–1900, women were placed in mental institutions for behaving in ways the male society did not agree with." These men had the last say when it came to the mental health of these women, so if they believed that these women were mentally ill, or if they simply wanted to silence the voices and opinions of these women, they could easily send them to mental institutions. This was an easy way to render them vulnerable and submissive.
An early fictional example is Mary Wollstonecraft's posthumously published novel Maria: or, The Wrongs of Woman (1798), in which the title character is confined to an insane asylum when she becomes inconvenient to her husband. Real women's stories reached the public through court cases: Louisa Nottidge was abducted by male relatives to prevent her committing her inheritance and her life to live in a revivalist clergyman's intentional community. Wilkie Collins based his 1859 novel The Woman in White on this case, dedicating it to Bryan Procter, the Commissioner for Lunacy. A generation later, Rosina Bulwer Lytton, daughter of the women's rights advocate Anna Wheeler, was locked up by her husband Edward Bulwer-Lytton and subsequently wrote of this in A Blighted Life (1880).
In 1887, journalist Nellie Bly had herself committed to the Blackwell's Island Insane Asylum in New York City, in order to investigate conditions there. Her account was published in the New York World newspaper, and in book form as Ten Days in a Mad-House.
In 1902, Margarethe von Ende de, wife of the German arms manufacturer Friedrich Alfred Krupp, was consigned to an insane asylum by Kaiser Wilhelm II, a family friend, when she asked him to respond to reports of her husband's gay orgies on Capri.
New practices
In continental Europe, universities often played a part in the administration of the asylums. In Germany, many practising psychiatrists were educated in universities associated with particular asylums. However, because Germany remained a loosely bound conglomerate of individual states, it lacked a national regulatory framework for asylums.
Although Tuke, Pinel and others had tried to do away with physical restraint, it remained widespread in the 19thcentury. At the Lincoln Asylum in England, Robert Gardiner Hill, with the support of Edward Parker Charlesworth, pioneered a mode of treatment that suited "all types" of patients, so that mechanical restraints and coercion could be dispensed with—a situation he finally achieved in 1838. In 1839 Sergeant John Adams and Dr. John Conolly were impressed by the work of Hill, and introduced the method into their Hanwell Asylum, by then the largest in the country. Hill's system was adapted, since Conolly was unable to supervise each attendant as closely as Hill had done. By September 1839, mechanical restraint was no longer required for any patient.
William A. F. Browne (1805–1885) introduced activities for patients including writing, art, group activity and drama, pioneered early forms of occupational therapy and art therapy, and initiated one of the earliest collections of artistic work by patients, at Montrose Asylum.
Rapid expansion
By the end of the 19thcentury, national systems of regulated asylums for the mentally ill had been established in most industrialized countries. At the turn of the century, Britain and France combined had only a few hundred people in asylums, but by the end of the century this number had risen to the hundreds of thousands. The United States housed 150,000 patients in mental hospitals by 1904. Germany housed more than 400 public and private sector asylums. These asylums were critical to the evolution of psychiatry as they provided places of practice throughout the world.
However, the hope that mental illness could be ameliorated through treatment during the mid-19thcentury was disappointed. Instead, psychiatrists were pressured by an ever-increasing patient population. The average number of patients in asylums in the United States jumped 927%. Numbers were similar in Britain and Germany. Overcrowding was rampant in France, where asylums would commonly take in double their maximum capacity. Increases in asylum populations may have been a result of the transfer of care from families and poorhouses, but the specific reasons as to why the increase occurred are still debated today. No matter the cause, the pressure on asylums from the increase was taking its toll on the asylums and psychiatry as a specialty. Asylums were once again turning into custodial institutions and the reputation of psychiatry in the medical world had hit an extreme low.
In the 1800s, middle class facilities became more common, replacing private care for wealthier persons. However, facilities in this period were largely oversubscribed. Individuals were referred to facilities either by the community or by the criminal justice system. Dangerous or violent cases were usually given precedence for admission. A survey taken in 1891 in Cape Town, South Africa shows the distribution between different facilities. Out of 2046 persons surveyed, 1,281 were in private dwellings, 120 in jails and 645 in asylums, with men representing nearly two-thirds of the number surveyed.
Defining someone as insane was a necessary prerequisite for being admitted to a facility. A doctor was only called after someone was labelled insane on social terms and had become socially or economically problematic. Until the 1890s, little distinction existed between the lunatic and criminal lunatic. The term was often used to police vagrancy as well as paupers and the insane. In the 1850s, lurid rumours that medical doctors were declaring normal people "insane" in Britain, were spread by the press causing widespread public anxiety. The fear was that people who were a source of embarrassment to their families were conveniently disposed of into asylums with the willing connivance of the psychiatric profession. This sensationalism appeared in widely read novels of the time, including The Woman in White.
20th century
Physical therapies
A series of radical physical therapies were developed in central and continental Europe in the late 1910s, the 1920s and most particularly, the 1930s. Among these, we may note the Austrian psychiatrist Julius Wagner-Jauregg's malarial therapy for general paresis of the insane (or neurosyphilis) first used in 1917, and for which he won a Nobel Prize in 1927. This treatment heralded the beginning of a radical and experimental era in psychiatric medicine that increasingly broke with an asylum-based culture of therapeutic nihilism in the treatment of chronic psychiatric disorders, most particularly dementia praecox (increasingly known as schizophrenia from the 1910s, although the two terms were used more or less interchangeably until at least the end of the 1930s), which were typically regarded as hereditary degenerative disorders and therefore unamenable to any therapeutic intervention. Malarial therapy was followed in 1920 by barbiturate-induced deep sleep therapy to treat dementia praecox, which was popularised by the Swiss psychiatrist Jakob Klaesi. In 1933 the Vienna-based psychiatrist Manfred Sakel introduced insulin shock therapy, and in August 1934 Ladislas J. Meduna, a Hungarian neuropathologist and psychiatrist working in Budapest, introduced cardiazol shock therapy (cardiazol is the tradename of the chemical compound pentylenetetrazol, known by the tradename metrazol in the United States), which was the first convulsive or seizure therapy for a psychiatric disorder. Again, both of these therapies were initially targeted at curing dementia praecox. Cardiazol shock therapy, founded on the theoretical notion that there existed a biological antagonism between schizophrenia and epilepsy and that therefore inducing epileptiform fits in schizophrenic patients might effect a cure, was superseded by electroconvulsive therapy (ECT), invented by the Italian neurologist Ugo Cerletti in 1938.
The use of psychosurgery was narrowed to a very small number of people for specific indications. Egas Moniz performed the first leucotomy, or lobotomy in Portugal in 1935, which targets the brain's frontal lobes. This was shortly thereafter adapted by Walter Freeman and James W. Watts in what is known as Freeman–Watts procedure or the standard prefrontal lobotomy. From 1946, Freeman developed the transorbital lobotomy, using a device akin to an ice-pick. This was an "office" procedure which did not have to be performed in a surgical theatre and took as little as fifteen minutes to complete. Freeman is credited with the popularisation of the technique in the United States. In 1949, 5,074 lobotomies were carried out in the United States and by 1951, 18,608 people had undergone the controversial procedure in that country. One of the most famous people to have a lobotomy was the sister of John F. Kennedy, Rosemary Kennedy, who was rendered profoundly intellectually disabled as a result of the surgery.
In modern times, insulin shock therapy and lobotomies are viewed as being almost as barbaric as the Bedlam "treatments", although the insulin shock therapy was still seen as the only option which produced any noticeable effect on patients. ECT is still used in the West in the 21stcentury, but it is seen as a last resort for treatment of mood disorders and is administered much more safely than in the past. Elsewhere, particularly in India, use of ECT is reportedly increasing, as a cost-effective alternative to drug treatment. The effect of a shock on an overly excitable patient often allowed these patients to be discharged to their homes, which was seen by administrators (and often guardians) as a preferable solution to institutionalisation. Lobotomies were performed in the thousands from the 1930s to the 1950s, and were ultimately replaced with modern psychotropic drugs.
Eugenics movement
The eugenics movement of the early 20thcentury led to a number of countries enacting laws for the compulsory sterilization of the "feeble minded", which resulted in the forced sterilization of numerous psychiatric inmates. As late as the 1950s, laws in Japan allowed the forcible sterilization of patients with psychiatric illnesses.
Under Nazi Germany, the Aktion T4 euthanasia program resulted in the killings of thousands of the mentally ill housed in state institutions. In 1939, the Nazis secretly began to exterminate the mentally ill in a euthanasia campaign. Around 6,000 disabled babies, children and teenagers were murdered by starvation or lethal injection.
Psychiatric internment as a political device
Psychiatrists around the world have been involved in the suppression of individual rights by states wherein the definitions of mental disease had been expanded to include political disobedience. Nowadays, in many countries, political prisoners are sometimes confined to mental institutions and abused therein. Psychiatry possesses a built-in capacity for abuse which is greater than in other areas of medicine. The diagnosis of mental disease can serve as proxy for the designation of social dissidents, allowing the state to hold persons against their will and to insist upon therapies that work in favour of ideological conformity and in the broader interests of society.
In a monolithic state, psychiatry can be used to bypass standard legal procedures for establishing guilt or innocence and allow political incarceration without the ordinary odium attaching to such political trials. In Nazi Germany in the 1940s, the 'duty to care' was violated on an enormous scale: A reported 300,000 individuals were sterilised and 100,000 killed in Germany alone, as were many thousands further afield, mainly in Eastern Europe.
From the 1960s up to 1986, political abuse of psychiatry was reported to be systematic in the Soviet Union, and to surface on occasion in other Eastern European countries such as Romania, Hungary, Czechoslovakia and Yugoslavia. A "mental health genocide" reminiscent of the Nazi aberrations has been located in the history of South African oppression during the apartheid era. A continued misappropriation of the discipline was subsequently attributed to the People's Republic of China.
Drugs
The 20thcentury saw the development of the first effective psychiatric drugs.
The first anti-psychotic drug, chlorpromazine (known under the trade name Largactil in Europe and Thorazine in the United States), was first synthesized in France in 1950. Pierre Deniker, a psychiatrist of the Saint-Anne Psychiatric Center in Paris, is credited with first recognising the specificity of action of the drug in psychosis in 1952. Denier traveled with a colleague to the United States and Canada promoting the drug at medical conferences in 1954. The first publication regarding its use in North America was made in the same year by the Canadian psychiatrist Heinz Lehmann, who was based in Montreal. Also in 1954 another antipsychotic, reserpine, was first used by an American psychiatrist based in New York, Nathan S. Kline. At a Paris-based colloquium on neuroleptics (antipsychotics) in 1955 a series of psychiatric studies were presented by, among others, Hans Hoff (Vienna), Dr. Ihsan Aksel (Istanbul), Felix Labarth (Basle), Linford Rees (London), Sarro (Barcelona), Manfred Bleuler (Zurich), Willi Mayer-Gross (Birmingham), Winford (Washington) and Denber (New York) attesting to the effective and concordant action of the new drugs in the treatment of psychosis.
The new antipsychotics had an immense impact on the lives of psychiatrists and patients. For instance, Henri Ey, a French psychiatrist at Bonneval, related that between 1921 and 1937 only 6% of patients with schizophrenia and chronic delirium were discharged from his institution. The comparable figure for the period from 1955 to 1967, after the introduction of chlorpromazine, was 67%. Between 1955 and 1968 the residential psychiatric population in the United States dropped by 30%. Newly developed antidepressants were used to treat cases of depression, and the introduction of muscle relaxants allowed ECT to be used in a modified form for the treatment of severe depression and a few other disorders.
The discovery of the mood stabilizing effect of lithium carbonate by John Cade in 1948 would eventually revolutionise the treatment of bipolar disorder, although its use was banned in the United States until the 1970s.
United States: reform in the 1940s
From 1942 to 1947, conscientious objectors in the US assigned to psychiatric hospitals under Civilian Public Service exposed abuses throughout the psychiatric care system and were instrumental in reforms of the 1940s and 1950s. The CPS reformers were especially active at the Philadelphia State Hospital where four Quakers initiated The Attendant magazine as a way to communicate ideas and promote reform. This periodical later became The Psychiatric Aide, a professional journal for mental health workers. On 6 May 1946, Life magazine printed an exposé of the psychiatric system by Albert Q. Maisel based on the reports of COs. Another effort of CPS, namely the Mental Hygiene Project, became the national Mental Health Foundation. Initially skeptical about the value of Civilian Public Service, Eleanor Roosevelt, impressed by the changes introduced by COs in the mental health system, became a sponsor of the National Mental Health Foundation and actively inspired other prominent citizens including Owen J. Roberts, Pearl Buck and Harry Emerson Fosdick to join her in advancing the organization's objectives of reform and humane treatment of patients.
Deinstitutionalisation
By the beginning of the 20thcentury, ever-increasing admissions had resulted in serious overcrowding. Funding was often cut, especially during periods of economic decline, and during wartime in particular many patients starved to death. Asylums became notorious for poor living conditions, lack of hygiene, overcrowding, and ill-treatment and abuse of patients.
The first community-based alternatives were suggested and tentatively implemented in the 1920s and 1930s, although asylum numbers continued to increase up to the 1950s. The movement for deinstitutionalisation came to the fore in various Western countries in the 1950s and 1960s.
The prevailing public arguments, time of onset, and pace of reforms varied by country. Class action lawsuits in the United States, and the scrutiny of institutions through disability activism and antipsychiatry, helped expose the poor conditions and treatment. Sociologists and others argued that such institutions maintained or created dependency, passivity, exclusion and disability, causing people to be institutionalised.
There was an argument that community services would be cheaper. It was suggested that new psychiatric medications made it more feasible to release people into the community.
There were differing views on deinstitutionalization, however, in groups such as mental health professionals, public officials, families, advocacy groups, public citizens and unions.
Today
Africa
Uganda has one psychiatric hospital.
South Africa currently has 27 registered psychiatric hospitals. These hospitals are spread throughout the country. Some of the most well-known institutions are: Weskoppies Psychiatric Hospital, colloquially known as Groendakkies ("Little Green Roofs") and Denmar Psychiatric Hospital in Pretoria, TARA in Johannesburg, and Valkenberg Hospital in Cape Town.
Asia
In Japan, the number of hospital beds has risen steadily over the last few decades.
In Hong Kong, a number of residential care services such as half-way houses, long-stay care homes, and supported hostels are provided for the discharged patients. In addition, a number of community support services such as Community Rehabilitation Day Services, Community Mental Health Link, Community Mental Health Care, etc. have been launched to facilitate the re-integration of patients into the community.
Europe
Countries where deinstitutionalisation has happened may be experiencing a process of "re-institutionalisation" or relocation to different institutions, as evidenced by increases in the number of supported housing facilities, forensic psychiatric beds and rising numbers in the prison population.
New Zealand
New Zealand established a reconciliation initiative in 2005 in the context of ongoing compensation payouts to ex-patients of state-run mental institutions in the 1970s to 1990s. The forum heard of poor reasons for admissions; unsanitary and overcrowded conditions; lack of communication to patients and family members; physical violence and sexual misconduct and abuse; inadequate complaints mechanisms; pressures and difficulties for staff, within an authoritarian psychiatric hierarchy based on containment; fear and humiliation in the misuse of seclusion; over-use and abuse of ECT, psychiatric medication and other treatments/punishments, including group therapy, with continued adverse effects; lack of support on discharge; interrupted lives and lost potential; and continued stigma, prejudice and emotional distress and trauma.
There were some references to instances of helpful aspects or kindnesses despite the system. Participants were offered counselling to help them deal with their experiences, and advice on their rights, including access to records and legal redress.
South America
In several South American countries, the total number of beds in asylum-type institutions has decreased, replaced by psychiatric inpatient units in general hospitals and other local settings.
United Kingdom
At the beginning of the 19thcentury, there were, perhaps, a few thousand "lunatics" housed in a variety of disparate institutions; but, by the beginning of the 20thcentury, that figure had grown to about 100,000. This growth coincided with the development of "alienism," now known as psychiatry, as a medical specialty.
United States
The United States has experienced two waves of deinstitutionalization. Wave one began in the 1950s and targeted people with mental illness. The second wave began roughly fifteen years after and focused on individuals who had been diagnosed with a developmental disability (e.g. intellectual disability).
A process of indirect cost-shifting may have led to a form of "re-institutionalization" through the increased use of jail detention for those with mental disorders deemed unmanageable and noncompliant. In summer 2009, author and columnist Heather Mac Donald stated in City Journal, "jails have become society's primary mental institutions, though few have the funding or expertise to carry out that role properly... at Rikers, 28% of the inmates require mental health services, a number that rises each year."
See also
Deinstitutionalization
History of mental disorders
Kirkbride Plan
Timeline of psychiatry
History of psychiatric institutions in China
List of asylums commissioned in England and Wales
Ann Pratt
References
Further reading
Michel Foucault, Histoire de la folie à l'âge classique, 1961, Gallimard, Tel, 688 p.
Claude Quétel, Histoire de la folie : De l'Antiquité à nos jours, 2009, Editions Tallandier, Texto, 618 pages.
Total institutions | Lunatic asylum | Biology | 7,559 |
69,687,005 | https://en.wikipedia.org/wiki/Samsung%20Galaxy%20A53%205G | The Samsung Galaxy A53 5G is a mid-range Galaxy phone developed and manufactured by Samsung Electronics as a part of its Galaxy
A series. The phone was announced on 17 March 2022 at Samsung Galaxy Unpacked event alongside the Galaxy A33 5G and Galaxy A73 5G.
Galaxy A53 5G Phone's price is $449 for a 128 GB model. The size of the screen is 6.5-inch which runs on Samsung's Exynos 1280 processor. Galaxy A53 has quad-camera system featuring 64 MP main camera with 32 MP front camera. Galaxy A53 is the first Samsung's A series device to get 5 years of software updates.
Design
The display is made of Corning Gorilla Glass 5. The back panel and side are made of frosted plastic.
The design of the Galaxy A53 looks almost similar to its predecessor, but the rear panel is now completely flat, and the transition between the rear panel and the camera unit is smoother. Also Galaxy A53 5G has protection against moisture and dust according to the IP67 standard.
Below are USB-C connector, speaker, microphone and depending on the version slot for 1 SIM card and microSD memory card up to 1 TB or hybrid slot for 2 SIM cards. The second microphone is located on top. On the right side are the volume buttons and the smartphone lock button.
The smartphone is sold in 4 colors: black (Awesome Black), white (Awesome White), blue (Awesome Blue) and orange (Awesome Peach).
Specifications
Hardware
The Galaxy A53 5G is a smartphone with a slate-type factor form, which is 159.6 × 74.8 × 8.1 mm in size and weighs 189 grams.
The device is equipped with GSM, HSPA, LTE and 5G connectivity, Wi-Fi 802.11 a/b/g/n/ac dual-band with Bluetooth 5.1, Wi-Fi Direct support and hotspot support with A2DP and LE, GPS with BeiDou, Galileo, GLONASS and QZSS and NFC. It has a USB Type-C 2.0 port. It is dust and water resistant with IP67 certification.
Display
It has a 6.5 inch diagonal Super AMOLED display with Infinity-O-type punch-hole camera, rounded corners, FHD+ resolution of 1080 × 2400 pixels, with an adaptive refresh rate up to 120 Hz protected by Gorilla Glass 5.
Battery
The 5000mAh lithium polymer battery being non-removable and supporting fast charging at 25 W means that the device has a high-capacity battery that can last a long time between charges and can be charged quickly when needed.
Processor
The device has a Samsung Exynos 1280 chipset with an octa-core CPU (2 cores at 2.4 GHz + 6 cores at 2 GHz) that enables the device to handle demanding tasks and optimize power consumption. It has UFS 2.0 internal memory with 128/256 GB storage and microSD expandable up to 1 TB. The RAM is either 6 or 8 GB (depending on the version chosen), which allows for smooth multitasking and running demanding apps.
Camera
The devices rear camera array features four cameras, including a 64 MP main camera, a 12 MP ultrawide camera, a 5 MP macro camera, and a 5 MP depth camera. These cameras work together to capture high-quality photos and videos from different perspectives. In addition to the main camera's high resolution and the ultrawide camera's wider field of view, the macro camera is designed for capturing extreme close-up shots of small objects, while the depth camera captures depth information to create portrait mode photos with a blurred background or add depth information to other types of photos and videos for a more immersive experience.
Software
The phone comes with Android 12 and One UI 4.1 and this Galaxy device is expected to get updated until One UI 8.1
References
A53 5G
Mobile phones introduced in 2022
Android (operating system) devices
Galaxy A53 5G
Phablets
Mobile phones with multiple rear cameras
Mobile phones with 4K video recording
Discontinued Samsung Galaxy smartphones | Samsung Galaxy A53 5G | Technology | 858 |
45,246,864 | https://en.wikipedia.org/wiki/Manot%20Cave | Manot Cave ( Me'arat Manot) is a cave in Western Galilee, Israel, discovered in 2008. It is notable for the discovery of a skull that belongs to a modern human, called Manot 1, which is estimated to be 54,700 years old (U–Th dating of the calcitic crust on the Manot 1 calvaria and of speleothems in the cave). The partial skull was discovered at the beginning of the cave's exploration in 2008. Its significance was realised after detailed scientific analysis, and was first published in an online edition of Nature on 28 January 2015. This age implies that the specimen is the oldest known human outside Africa, and is evidence that modern humans lived side-by-side with Neanderthals. The cave is also noted for its "impressive archaeological record of flint and bone artefacts". Geologically, it is an "active stalactite cave".
Discovery
Manot Cave is situated in Western Galilee, about 10 km north of HaYonim Cave and 50 km northeast of Mt. Carmel. It was discovered accidentally during construction work in 2008 when a bulldozer struck open its roof. Experts from the Cave Research Unit of Hebrew University of Jerusalem immediately made the initial survey. Important finds were stone tools, charcoal pieces, and human remains. The tools consisted of a Levallois point, burins, bladelets, overpassed blades, and Aurignacian tools such as nosed and carinated endscrapers. There were also remains of "fallow deer, red deer, mountain gazelle, horse, aurochs, hyena, and bear". The major find was an almost complete human skull. The finds were reported to the Israel Antiquities Authority (IAA), which granted another survey. Ofer Marder and H. Khalaily made the survey and found that it was a rich archaeological site. Recognising its importance, the IAA granted a full-scale excavation in 2010. For three weeks the site was excavated by a collaboration of archaeologists from Hebrew University of Jerusalem, Tel Aviv University, Geological Survey of Israel, Zinman Institute of Archaeology of University of Haifa, Kimmel Center for Archaeological Sciences of Weizmann Institute of Science, and the Department of Archaeology of Boston University.
Description
The Manot Cave consists of a lengthy hall, 80 m long and between 10m and 25m wide. Two lower chambers are connected to it from north and south. It is possible that the main entrances were at both the eastern and western ends. The cave has active stalagmite formations. Archaeological remains indicate that the most recent artifacts belong to the Early Palaeolithic period. This further indicates that the cave had been completely sealed for at least 15,000 years. The blockage was probably due to rock falls and active stalagmites at the main entrances.
Chronology
Archaeologists have offered the following chronology for the cave, based on radiocarbon dating: an Early Ahmarian phase (46,000–42,000 BP), a Levantine Aurignacian phase (38,000–34,000 BP), and a post-Levantine Aurignacian phase (34,000–33,000 BP).
Significance in human evolution
The most important find in the cave is a partial skullcap of a modern human, referred to by archaeologists as Manot 1. The specimen is estimated (using uranium–thorium dating) to be 54,700 years old. It shows that modern humans lived together with another human species, the Neanderthals, in the Levant. This could support the notion that these two species had interbred, as evidenced by genome sequencing.
See also
Kebara Cave
Ksar Akil
References
2008 archaeological discoveries
Caves of Israel
Archaeological sites in Israel
Human evolution
Recent African origin of modern humans
Prehistoric sites in Israel
Neanderthal sites
Levantine Aurignacian | Manot Cave | Biology | 799 |
38,562,377 | https://en.wikipedia.org/wiki/Chelyabinsk%20meteorite | The Chelyabinsk meteorite (Russian: Челябинский метеорит, Chelyabinskii meteorit) is the fragmented remains of the large Chelyabinsk meteor of 15 February 2013 which reached the ground after the meteor's passage through the atmosphere. The descent of the meteor, visible as a brilliant superbolide in the morning sky, caused a series of shock waves that shattered windows, damaged approximately 7,200 buildings and left 1,491 people injured. The resulting fragments were scattered over a wide area.
The largest fragment raised from the bottom of Lake Chebarkul on 16 October 2013 had a mass of and the total mass of other 7 meteorite fragments found nearby was .
Naming
The meteor and meteorite are named after Chelyabinsk Oblast, over which the meteor exploded. An initial proposal was to name the meteorite after Lake Chebarkul, where one of its major fragments impacted and made a hole in the frozen lake surface.
Composition and classification
The meteorite has been classified as an LL5 ordinary chondrite. First estimates of its composition indicate about 10% of meteoric iron, as well as olivine and sulfides.
Asteroid
The impacting asteroid started to brighten up in the general direction of the Pegasus constellation, close to the East horizon where the Sun was starting to rise. The impactor belonged to the Apollo group of near-Earth asteroids.
The asteroid had an approximate size of and a mass of about before it entered the denser parts of Earth's atmosphere and started to ablate. At an altitude of about 23.3 km (14.5 miles) the body exploded in a meteor air burst. Meteorite fragments of the body landed on the ground.
Analysis of three fragments using optical microscopy, electron microscopy, Raman spectroscopy, and isotopic composition techniques used to date Solar System objects, showed the isotopic clocks in the asteroids (rubidium and strontium ratios, argon isotope ratios) appear to have partially or totally reset in past collisions. The isotopic clock resets may result from thermal effects changing isotopic ratios, and changes due to cosmic radiation exposure. The asteroid appears to have had eight major collisions, around 4.53, 4.45, 3.73, 2.81, and 1.46 billion years ago, then at 852, 312, and 27 million years ago.
Meteorite
Scientists collected 53 samples from near a hole in the ice of Lake Chebarkul, thought to be the result of a single meteorite fragment impact. The specimens are of various sizes, with the largest being , and initial laboratory analysis confirmed their meteoric origin.
In June 2013, Russian scientists reported that further investigation by magnetic imaging below the location of the ice hole in Lake Chebarkul had identified a meteorite buried in the mud at the bottom of the lake. An operation to recover it from the lake began on 10 September 2013, and concluded on 16 October 2013, with the raising of the rock with the mass of . It was examined by scientists and handed over to the local authorities, who put it on display at the Chelyabinsk State Museum of Local Lore.
In the aftermath of the superbolide air burst, a large number of small meteorite fragments fell on areas west of Chelyabinsk, including Deputatskoye, generally at terminal velocity, about the speed of a piece of gravel dropped from a skyscraper. Local residents and schoolchildren located and picked up some of the meteorites, many located in snowdrifts, by following a visible hole that had been left in the outer surface of the snow. Speculators became active in the informal market for meteorite fragments that rapidly emerged.
Popular culture
, some reports surfaced of people trying to sell fake meteorites on the Internet.
On 15 February (anniversary of the event), during the 2014 Winter Olympics, winners received medals with embedded fragments of the meteorite.
Andrey Breyvichko claimed to have founded a "Church of the Chelyabinsk Meteorite" in the Russian city of Chelyabinsk. Breyvichko opposes the operation to expose the meteorite fragment in a museum, claiming that only "psychic priests" of his church are qualified to decode and handle the celestial body, which they want to be placed in a temple to be built in Chelyabinsk for the purpose.
Gallery
See also
Meteorite fall
References
External links
Chelyabinsk Meteorite oxfordre.com
Chondrite meteorites
Meteorites found in Russia
2013 in Russia
2013 in outer space
Modern Earth impact events
Meteorite
February 2013 events in Russia
21st-century astronomical events | Chelyabinsk meteorite | Astronomy | 959 |
541,110 | https://en.wikipedia.org/wiki/Java%20Metadata%20Interface | Given that metadata is a set of descriptive, structural and administrative data about a group of computer data (for example such as a database schema), Java Metadata Interface (or JMI) is a platform-neutral specification that defines the creation, storage, access, lookup and exchange of metadata in the Java programming language.
History
The JMI specification was developed under the Java Community Process and is defined by JSR 40 (a JSR is the formal document that describe proposed specifications and technologies for adding to the Java platform).
JMI is based on the Meta-Object Facility (or MOF) specification from the Object Management Group (or OMG). The MOF is a metamodel (a model of any kind of metadata) used notably to define the Unified Modeling Language (or UML).
It supports the exchange of metadata through XMI. XMI is a standard for exchanging metadata information via Extensible Markup Language (or XML). The MOF/XMI specifications are used for the exchange of UML models.
Usage
Essentially, JMI can be used to write tools in Java for manipulating UML models, which can be used in Model Driven Architecture and/or Model Driven Development. There are many implementations of JMI, including the Reference Implementation from Unisys, SAP NetWeaver and Sun Microsystems's open-source implementation from the NetBeans group. JMI is compatible with Java SE 1.3 and above through:
Standardized mappings from the MOF modeling constructs to Java;
Reflective APIs for generic discovery and navigation of metadata models and instances.
See also
External links
JSR 40
Metadata Interface
Metadata | Java Metadata Interface | Technology | 337 |
1,613,644 | https://en.wikipedia.org/wiki/Interleukin%206 | Interleukin 6 (IL-6) is an interleukin that acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine. In humans, it is encoded by the IL6 gene.
In addition, osteoblasts secrete IL-6 to stimulate osteoclast formation. Smooth muscle cells in the tunica media of many blood vessels also produce IL-6 as a pro-inflammatory cytokine. IL-6's role as an anti-inflammatory myokine is mediated through its inhibitory effects on TNF and IL-1 and its activation of IL-1ra and IL-10.
There is some early evidence that IL-6 can be used as an inflammatory marker for severe COVID-19 infection with poor prognosis, in the context of the wider coronavirus pandemic.
Function
Immune system
IL-6 is secreted by macrophages in response to specific microbial molecules, referred to as pathogen-associated molecular patterns (PAMPs). These PAMPs bind to an important group of detection molecules of the innate immune system, called pattern recognition receptors (PRRs), including Toll-like receptors (TLRs). These are present on the cell surface and intracellular compartments and induce intracellular signaling cascades that give rise to inflammatory cytokine production. IL-6 is an important mediator of fever and of the acute phase response.
IL-6 is responsible for stimulating acute phase protein synthesis, as well as the production of neutrophils in the bone marrow. It supports the growth of B cells and is antagonistic to regulatory T cells.
Metabolic
It is capable of crossing the blood–brain barrier and initiating synthesis of PGE2 in the hypothalamus, thereby changing the body's temperature setpoint. In muscle and fatty tissue, IL-6 stimulates energy mobilization that leads to increased body temperature. At 4°C, both the oxygen consumption and core temperature were lower in IL-6-/- compared with wild-type mice, suggesting a lower cold-induced thermogenesis in IL-6-/- mice.
In the absence of inflammation 10–35% of circulating IL-6 may come from adipose tissue. IL-6 is produced by adipocytes and is thought to be a reason why obese individuals have higher endogenous levels of CRP. IL-6 may exert a tonic suppression of body fat in mature mice, given that IL-6 gene knockout causes mature onset obesity. Moreover, IL-6 can suppress body fat mass via effects at the level of the CNS. The antiobesity effect of IL-6 in rodents is exerted at the level of the brain, presumably the hypothalamus and the hindbrain. On the other hand, enhanced central IL-6 trans-signaling may improve energy and glucose homeostasis in obesity Trans-signaling implicates that a soluble form of IL-6R (sIL-6R) comprising the extracellular portion of the receptor can bind IL-6 with a similar affinity as the membrane bound IL-6R. The complex of IL-6 and sIL-6R can bind to gp130 on cells, which do not express the IL-6R, and which are unresponsive to IL-6.
Studies in experimental animals indicate that IL-6 in the CNS partly mediates the suppression of food intake and body weight exerted by glucagon-like peptide-1 (GLP-1) receptor stimulation.
Outside the CNS, it seems that IL-6 stimulates the production of GLP-1 in the endocrine pancreas and the gut. Amylin is another substance that can reduce body weight, and that may interact with IL-6. Amylin-induced IL-6 production in the ventromedial hypothalamus (VMH) is a possible mechanism by which amylin treatment could interact with VMH leptin signaling to increase its effect on weight loss.
It is assumed that interleukin 6 in the liver activates the homologue of the human longevity gene mINDY expression via binding to its IL-6-receptor, which is associated with activation of the transcription factor STAT3 (which binds to the binding site in the mIndy promoter) and thereby rise of citrate uptake and hepatic lipogenesis.
Central nervous system
Intranasally administered IL-6 has been shown to improve sleep-associated consolidation of emotional memories.
There are indications of interactions between GLP-1 and IL-6 in several parts of the brain. One example is the parabrachial nuclei of the pons, where GLP-1 increases IL-6 levels and where IL-6 exerts a marked anti-obesity effect.
Role as myokine
IL-6 is also considered a myokine, a cytokine produced from muscle, which is elevated in response to muscle contraction. It is significantly elevated with exercise, and precedes the appearance of other cytokines in the circulation. During exercise, it is thought to act in a hormone-like manner to mobilize extracellular substrates and/or augment substrate delivery.
Like in humans, there seems to be an increase in IL-6 expression in working muscle and plasma IL-6 concentration during exercise in rodents. Studies in mice with IL-6 gene knockout indicate that lack of IL-6 in mice affect exercise function.
It has been shown that the reduction of abdominal obesity by exercise in human adults can be reversed by the IL-6 receptor blocking antibody tocilizumab. Together with the findings that IL-6 prevents obesity, stimulates lipolysis and is released from skeletal muscle during exercise, the tocilizumab finding indicates that IL-6 is required for exercise to reduce visceral adipose tissue mass. Bone may be another organ affected by exercise induced IL-6, given that muscle-derived interleukin 6 has been reported to increase exercise capacity by signaling in osteoblasts.
IL-6 has extensive anti-inflammatory functions in its role as a myokine. IL-6 was the first myokine that was found to be secreted into the blood stream in response to muscle contractions. Aerobic exercise provokes a systemic cytokine response, including, for example, IL-6, IL-1 receptor antagonist (IL-1ra), and IL-10. IL-6 was serendipitously discovered as a myokine because of the observation that it increased in an exponential fashion proportional to the length of exercise and the amount of muscle mass engaged in the exercise. It has been consistently demonstrated that the plasma concentration of IL-6 increases during muscular exercise. This increase is followed by the appearance of IL-1ra and the anti-inflammatory cytokine IL-10. In general, the cytokine response to exercise and sepsis differs with regard to TNF-α. Thus, the cytokine response to exercise is not preceded by an increase in plasma-TNF-α. Following exercise, the basal plasma IL-6 concentration may increase up to 100-fold, but less dramatic increases are more frequent. The exercise-induced increase of plasma IL-6 occurs in an exponential manner and the peak IL-6 level is reached at the end of the exercise or shortly thereafter. It is the combination of mode, intensity, and duration of the exercise that determines the magnitude of the exercise-induced increase of plasma IL-6.
IL-6 had previously been classified as a proinflammatory cytokine. Therefore, it was first thought that the exercise-induced IL-6 response was related to muscle damage. However, it has become evident that eccentric exercise is not associated with a larger increase in plasma IL-6 than exercise involving concentric "nondamaging" muscle contractions. This finding clearly demonstrates that muscle damage is not required to provoke an increase in plasma IL-6 during exercise. As a matter of fact, eccentric exercise may result in a delayed peak and a much slower decrease of plasma IL-6 during recovery.
Recent work has shown that both upstream and downstream signalling pathways for IL-6 differ markedly between myocytes and macrophages. It appears that unlike IL-6 signalling in macrophages, which is dependent upon activation of the NFκB signalling pathway, intramuscular IL-6 expression is regulated by a network of signalling cascades, including the /NFAT and glycogen/p38 MAPK pathways. Thus, when IL-6 is signalling in monocytes or macrophages, it creates a pro-inflammatory response, whereas IL-6 activation and signalling in muscle is totally
independent of a preceding TNF-response or NFκB activation, and is anti-inflammatory.
IL-6, among an increasing number of other recently identified myokines, thus remains an important topic in myokine research. It appears in muscle tissue and in the circulation during exercise at levels up to one hundred times basal rates, as noted, and is seen as having a beneficial impact on health and bodily functioning when elevated in response to physical exercise.
Receptor
IL-6 signals through a cell-surface type I cytokine receptor complex consisting of the ligand-binding IL-6Rα chain (CD126), and the signal-transducing component gp130 (also called CD130). CD130 is the common signal transducer for several cytokines including leukemia inhibitory factor (LIF), ciliary neurotropic factor, oncostatin M, IL-11 and cardiotrophin-1, and is almost ubiquitously expressed in most tissues. In contrast, the expression of CD126 is restricted to certain tissues. As IL-6 interacts with its receptor, it triggers the gp130 and IL-6R proteins to form a complex, thus activating the receptor. These complexes bring together the intracellular regions of gp130 to initiate a signal transduction cascade through certain transcription factors, Janus kinases (JAKs) and Signal Transducers and Activators of Transcription (STATs).
IL-6 is probably the best-studied of the cytokines that use gp130, also known as IL-6 signal transducer (IL6ST), in their signalling complexes. Other cytokines that signal through receptors containing gp130 are Interleukin 11 (IL-11), Interleukin 27 (IL-27), ciliary neurotrophic factor (CNTF), cardiotrophin-1 (CT-1), cardiotrophin-like cytokine (CLC), leukemia inhibitory factor (LIF), oncostatin M (OSM), Kaposi's sarcoma-associated herpesvirus interleukin 6-like protein (KSHV-IL6). These cytokines are commonly referred to as the IL-6 like or gp130 utilising cytokines
In addition to the membrane-bound receptor, a soluble form of IL-6R (sIL-6R) has been purified from human serum and urine. Many neuronal cells are unresponsive to stimulation by IL-6 alone, but differentiation and survival of neuronal cells can be mediated through the action of sIL-6R. The sIL-6R/IL-6 complex can stimulate neurites outgrowth and promote survival of neurons and, hence, may be important in nerve regeneration through remyelination.
Interactions
Interleukin-6 has been shown to interact with interleukin-6 receptor, glycoprotein 130, and Galectin-3.
There is considerable functional overlap and interaction between Substance P (SP), the natural ligand for the neurokinin type 1 receptor (NK1R, a mediator of immunomodulatory activity) and IL-6.
Role in disease
IL-6 stimulates the inflammatory and auto-immune processes in many diseases such as multiple sclerosis, neuromyelitis optica spectrum disorder (NMOSD), diabetes, atherosclerosis, gastric cancer, depression, Alzheimer's disease, systemic lupus erythematosus, multiple myeloma, prostate cancer, Behçet's disease, rheumatoid arthritis, and intracerebral hemorrhage.
Hence, there is an interest in developing anti-IL-6 agents as therapy against many of these diseases. The first such is tocilizumab, which has been approved for rheumatoid arthritis, Castleman's disease and systemic juvenile idiopathic arthritis. Others are in clinical trials. It has been observed that genetic inactivation of ZCCHC 6 suppresses IL‐6 expression and reduces the severity of experimental osteoarthritis in Mice. Some plant derived small molecule such as Butein have been reported to inhibit IL-6 expression in IL-1β stimulated human chondrocytes.
Liver diseases
Since IL-6 is a well-known pleiotropic molecule, it plays a dual role in the pathogenesis of liver diseases. While it is necessary for promoting liver regeneration, IL-6 is also a highly recognized marker of systemic inflammation and its association with mortality in liver diseases has been reported by multiple studies. In patients with severe alcohol-associated hepatitis, IL-6 showed the most robust elevation among inflammatory cytokines compared to healthy controls with a further increase in non-survivors. In these patients, IL-6 was a predictor of short-term (28- and 90-day) mortality.
Rheumatoid arthritis
The first FDA approved anti-IL-6 treatment was for rheumatoid arthritis.
Cancer
Anti-IL-6 therapy was initially developed for treatment of autoimmune diseases, but due to the role of IL-6 in chronic inflammation, IL-6 blockade was also evaluated for cancer treatment. IL-6 was seen to have roles in tumor microenvironment regulation, production of breast cancer stem cell-like cells, metastasis through down-regulation of E-cadherin, and alteration of DNA methylation in oral cancer.
Advanced/metastatic cancer patients have higher levels of IL-6 in their blood. One example of this is pancreatic cancer, with noted elevation of IL-6 present in patients correlating with poor survival rates.
Diseases
Enterovirus 71
High IL-6 levels are associated with the development of encephalitis in children and immunodeficient mouse models infected with Enterovirus 71; this highly contagious virus normally causes a milder illness called Hand, foot, and mouth disease but can cause life-threatening encephalitis in some cases. EV71 patients with a certain gene polymorphism in IL-6 also appear to be more susceptible to developing encephalitis.
Epigenetic modifications
IL-6 has been shown to lead to several neurological diseases through its impact on epigenetic modification within the brain. IL-6 activates the Phosphoinositide 3-kinase (PI3K) pathway, and a downstream target of this pathway is the protein kinase B (PKB) (Hodge et al., 2007). IL-6 activated PKB can phosphorylate the nuclear localization signal on DNA methyltransferase-1 (DNMT1). This phosphorylation causes movement of DNMT1 to the nucleus, where it can be transcribed. DNMT1 recruits other DNMTs, including DNMT3A and DNMT3B, which, as a complex, recruit HDAC1. This complex adds methyl groups to CpG islands on gene promoters, repressing the chromatin structure surrounding the DNA sequence and inhibiting transcriptional machinery from accessing the gene to induce transcription. Increased IL-6, therefore, can hypermethylate DNA sequences and subsequently decrease gene expression through its effects on DNMT1 expression.
Schizophrenia
The induction of epigenetic modification by IL-6 has been proposed as a mechanism in the pathology of schizophrenia through the hypermethylation and repression of the GAD67 promoter. This hypermethylation may potentially lead to the decreased GAD67 levels seen in the brains of people with schizophrenia. GAD67 may be involved in the pathology of schizophrenia through its effect on GABA levels and on neural oscillations. Neural oscillations occur when inhibitory GABAergic neurons fire synchronously and cause inhibition of a multitude of target excitatory neurons at the same time, leading to a cycle of inhibition and disinhibition. These neural oscillations are impaired in schizophrenia, and these alterations may be responsible for both positive and negative symptoms of schizophrenia.
Aging
IL-6 is commonly found in the senescence-associated secretory phenotype (SASP) factors secreted by senescent cells (a toxic cell-type that increases with aging). Cancer (a disease that increases with age) invasiveness is promoted primarily though the actions of the SASP factors metalloproteinase, chemokine, IL-6, and interleukin 8 (IL-8). IL-6 and IL-8 are the most conserved and robust features of SASP.
Myelodysplastic Syndromes
IL-6 receptor was found upregulated in high-risk MDS patients. The inhibition of IL-6 signaling pathway can significantly ameliorate the clonogenicity of MDS hematopoietic stem and progenitor cells (HSPCs), but have undetectable effect on normal HSPCs.
Depression and major depressive disorder
The epigenetic effects IL-6 have also been implicated in the pathology of depression. The effects of IL-6 on depression are mediated through the repression of brain-derived neurotrophic factor (BDNF) expression in the brain; DNMT1 hypermethylates the BDNF promoter and reduces BDNF levels. Altered BDNF function has been implicated in depression, which is likely due to epigenetic modification following IL-6 upregulation. BDNF is a neurotrophic factor implicated in spine formation, density, and morphology on neurons. Downregulation of BDNF, therefore, may cause decreased connectivity in the brain. Depression is marked by altered connectivity, in particular between the anterior cingulate cortex and several other limbic areas, such as the hippocampus. The anterior cingulate cortex is responsible for detecting incongruences between expectation and perceived experience. Altered connectivity of the anterior cingulate cortex in depression, therefore, may cause altered emotions following certain experiences, leading to depressive reactions. This altered connectivity is mediated by IL-6 and its effect on epigenetic regulation of BDNF.
Additional preclinical and clinical data, suggest that Substance P [SP] and IL-6 may act in concert to promote major depression. SP, a hybrid neurotransmitter-cytokine, is co-transmitted with BDNF through paleo-spinothalamic circuitry from the periphery with collaterals into key areas of the limbic system. However, both IL6 and SP mitigate expression of BDNF in brain regions associated with negative affect and memory. SP and IL6 both relax tight junctions of the blood brain barrier, such that effects seen in fMRI experiments with these molecules may be a bidirectional mix of neuronal, glial, capillary, synaptic, paracrine, or endocrine-like effects. At the cellular level, SP is noted to increase expression of interleukin-6 (IL-6) through PI-3K, p42/44 and p38 MAP kinase pathways. Data suggest that nuclear translocation of NF-κB regulates IL-6 overexpression in SP-stimulated cells. This is of key interest as: 1) a meta-analysis indicates an association of major depressive disorder, C-reactive protein and IL6 plasma concentrations, 2) NK1R antagonists [five molecules] studied by 3 independent groups in over 2000 patients from 1998 to 2013 validate the mechanism as dose-related, fully effective antidepressant, with a unique safety profile. (see Summary of NK1RAs in Major Depression), 3) the preliminary observation that plasma concentrations of IL6 are elevated in depressed patients with cancer, and 4) selective NK1RAs may eliminate endogenous SP stress-induced augmentation of IL-6 secretion pre-clinically. These and many other reports suggest that a clinical study of a neutralizing IL-6 biological or drug based antagonist is likely warranted in patients with major depressive disorder, with or without co-morbid chronic inflammatory based illnesses; that the combination of NK1RAs and IL6 blockers may represent a new, potentially biomarkable approach to major depression, and possibly bipolar disorder.
The IL-6 antibody sirukumab underwent clinical trials for adjunctive treatment of major depressive disorder in 2015–2018, but this research has been discontinued.
Asthma
Obesity is a known risk factor in the development of severe asthma. Recent data suggests that the inflammation associated with obesity, potentially mediated by IL-6, plays a role in causing poor lung function and increased risk for developing asthma exacerbations.
Protein superfamily
Interleukin is the main member of the IL-6 superfamily (), which also includes G-CSF, IL23A, and CLCF1. A viral version of IL6 is found in Kaposi's sarcoma-associated herpesvirus.
See also
Ziltivekimab, a fully human monoclonal antibody against interleukin 6.
References
External links
IL-6 expression in various cancers
Interleukins
Osaka University research
Neurotrophic factors | Interleukin 6 | Chemistry | 4,592 |
2,233,526 | https://en.wikipedia.org/wiki/Basic%20hypergeometric%20series | In mathematics, basic hypergeometric series, or q-hypergeometric series, are q-analogue generalizations of generalized hypergeometric series, and are in turn generalized by elliptic hypergeometric series.
A series xn is called hypergeometric if the ratio of successive terms xn+1/xn is a rational function of n. If the ratio of successive terms is a rational function of qn, then the series is called a basic hypergeometric series. The number q is called the base.
The basic hypergeometric series was first considered by . It becomes the hypergeometric series in the limit when base .
Definition
There are two forms of basic hypergeometric series, the unilateral basic hypergeometric series φ, and the more general bilateral basic hypergeometric series ψ.
The unilateral basic hypergeometric series is defined as
where
and
is the q-shifted factorial.
The most important special case is when j = k + 1, when it becomes
This series is called balanced if a1 ... ak + 1 = b1 ...bkq.
This series is called well poised if a1q = a2b1 = ... = ak + 1bk, and very well poised if in addition a2 = −a3 = qa11/2.
The unilateral basic hypergeometric series is a q-analog of the hypergeometric series since
holds ().
The bilateral basic hypergeometric series, corresponding to the bilateral hypergeometric series, is defined as
The most important special case is when j = k, when it becomes
The unilateral series can be obtained as a special case of the bilateral one by setting one of the b variables equal to q, at least when none of the a variables is a power of q, as all the terms with n < 0 then vanish.
Simple series
Some simple series expressions include
and
and
The q-binomial theorem
The q-binomial theorem (first published in 1811 by Heinrich August Rothe) states that
which follows by repeatedly applying the identity
The special case of a = 0 is closely related to the q-exponential.
Cauchy binomial theorem
Cauchy binomial theorem is a special case of the q-binomial theorem.
Ramanujan's identity
Srinivasa Ramanujan gave the identity
valid for |q| < 1 and |b/a| < |z| < 1. Similar identities for have been given by Bailey. Such identities can be understood to be generalizations of the Jacobi triple product theorem, which can be written using q-series as
Ken Ono gives a related formal power series
Watson's contour integral
As an analogue of the Barnes integral for the hypergeometric series, Watson showed that
where the poles of lie to the left of the contour and the remaining poles lie to the right. There is a similar contour integral for r+1φr. This contour integral gives an analytic continuation of the basic hypergeometric function in z.
Matrix version
The basic hypergeometric matrix function can be defined as follows:
The ratio test shows that this matrix function is absolutely convergent.
See also
Dixon's identity
Rogers–Ramanujan identities
Notes
References
W.N. Bailey, Generalized Hypergeometric Series, (1935) Cambridge Tracts in Mathematics and Mathematical Physics, No.32, Cambridge University Press, Cambridge.
William Y. C. Chen and Amy Fu, Semi-Finite Forms of Bilateral Basic Hypergeometric Series (2004)
Exton, H. (1983), q-Hypergeometric Functions and Applications, New York: Halstead Press, Chichester: Ellis Horwood, , ,
Sylvie Corteel and Jeremy Lovejoy, Frobenius Partitions and the Combinatorics of Ramanujan's Summation
Victor Kac, Pokman Cheung, Quantum calculus, Universitext, Springer-Verlag, 2002.
. Section 0.2
Andrews, G. E., Askey, R. and Roy, R. (1999). Special Functions, Encyclopedia of Mathematics and its Applications, volume 71, Cambridge University Press.
Eduard Heine, Theorie der Kugelfunctionen, (1878) 1, pp 97–125.
Eduard Heine, Handbuch die Kugelfunctionen. Theorie und Anwendung'' (1898) Springer, Berlin.
External links
Q-analogs
Hypergeometric functions | Basic hypergeometric series | Mathematics | 908 |
78,534 | https://en.wikipedia.org/wiki/Geomorphology | Geomorphology () is the scientific study of the origin and evolution of topographic and bathymetric features generated by physical, chemical or biological processes operating at or near Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform and terrain history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology, and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field.
Overview
Earth's surface is modified by a combination of surface processes that shape landscapes, and geologic processes that cause tectonic uplift and subsidence, and shape the coastal geography. Surface processes comprise the action of water, wind, ice, wildfire, and life on the surface of the Earth, along with chemical reactions that form soils and alter material properties, the stability and rate of change of topography under the force of gravity, and other factors, such as (in the very recent past) human alteration of the landscape. Many of these factors are strongly mediated by climate. Geologic processes include the uplift of mountain ranges, the growth of volcanoes, isostatic changes in land surface elevation (sometimes in response to surface processes), and the formation of deep sedimentary basins where the surface of the Earth drops and is filled with material eroded from other parts of the landscape. The Earth's surface and its topography therefore are an intersection of climatic, hydrologic, and biologic action with geologic processes, or alternatively stated, the intersection of the Earth's lithosphere with its hydrosphere, atmosphere, and biosphere.
The broad-scale topographies of the Earth illustrate this intersection of surface and subsurface action. Mountain belts are uplifted due to geologic processes. Denudation of these high uplifted regions produces sediment that is transported and deposited elsewhere within the landscape or off the coast. On progressively smaller scales, similar ideas apply, where individual landforms evolve in response to the balance of additive processes (uplift and deposition) and subtractive processes (subsidence and erosion). Often, these processes directly affect each other: ice sheets, water, and sediment are all loads that change topography through flexural isostasy. Topography can modify the local climate, for example through orographic precipitation, which in turn modifies the topography by changing the hydrologic regime in which it evolves. Many geomorphologists are particularly interested in the potential for feedbacks between climate and tectonics, mediated by geomorphic processes.
In addition to these broad-scale questions, geomorphologists address issues that are more specific or more local. Glacial geomorphologists investigate glacial deposits such as moraines, eskers, and proglacial lakes, as well as glacial erosional features, to build chronologies of both small glaciers and large ice sheets and understand their motions and effects upon the landscape. Fluvial geomorphologists focus on rivers, how they transport sediment, migrate across the landscape, cut into bedrock, respond to environmental and tectonic changes, and interact with humans. Soils geomorphologists investigate soil profiles and chemistry to learn about the history of a particular landscape and understand how climate, biota, and rock interact. Other geomorphologists study how hillslopes form and change. Still others investigate the relationships between ecology and geomorphology. Because geomorphology is defined to comprise everything related to the surface of the Earth and its modification, it is a broad field with many facets.
Geomorphologists use a wide range of techniques in their work. These may include fieldwork and field data collection, the interpretation of remotely sensed data, geochemical analyses, and the numerical modelling of the physics of landscapes. Geomorphologists may rely on geochronology, using dating methods to measure the rate of changes to the surface. Terrain measurement techniques are vital to quantitatively describe the form of the Earth's surface, and include differential GPS, remotely sensed digital terrain models and laser scanning, to quantify, study, and to generate illustrations and maps.
Practical applications of geomorphology include hazard assessment (such as landslide prediction and mitigation), river control and stream restoration, and coastal protection.
Planetary geomorphology studies landforms on other terrestrial planets such as Mars. Indications of effects of wind, fluvial, glacial, mass wasting, meteor impact, tectonics and volcanic processes are studied. This effort not only helps better understand the geologic and atmospheric history of those planets but also extends geomorphological study of the Earth. Planetary geomorphologists often use Earth analogues to aid in their study of surfaces of other planets.
History
Other than some notable exceptions in antiquity, geomorphology is a relatively young science, growing along with interest in other aspects of the earth sciences in the mid-19th century. This section provides a very brief outline of some of the major figures and events in its development.
Ancient geomorphology
The study of landforms and the evolution of the Earth's surface can be dated back to scholars of Classical Greece. In the 5th century BC, Greek historian Herodotus argued from observations of soils that the Nile delta was actively growing into the Mediterranean Sea, and estimated its age. In the 4th century BC, Greek philosopher Aristotle speculated that due to sediment transport into the sea, eventually those seas would fill while the land lowered. He claimed that this would mean that land and water would eventually swap places, whereupon the process would begin again in an endless cycle. The Encyclopedia of the Brethren of Purity published in Arabic at Basra during the 10th century also discussed the cyclical changing positions of land and sea with rocks breaking down and being washed into the sea, their sediment eventually rising to form new continents. The medieval Persian Muslim scholar Abū Rayhān al-Bīrūnī (973–1048), after observing rock formations at the mouths of rivers, hypothesized that the Indian Ocean once covered all of India. In his De Natura Fossilium of 1546, German metallurgist and mineralogist Georgius Agricola (1494–1555) wrote about erosion and natural weathering.
Another early theory of geomorphology was devised by Song dynasty Chinese scientist and statesman Shen Kuo (1031–1095). This was based on his observation of marine fossil shells in a geological stratum of a mountain hundreds of miles from the Pacific Ocean. Noticing bivalve shells running in a horizontal span along the cut section of a cliffside, he theorized that the cliff was once the pre-historic location of a seashore that had shifted hundreds of miles over the centuries. He inferred that the land was reshaped and formed by soil erosion of the mountains and by deposition of silt, after observing strange natural erosions of the Taihang Mountains and the Yandang Mountain near Wenzhou. Furthermore, he promoted the theory of gradual climate change over centuries of time once ancient petrified bamboos were found to be preserved underground in the dry, northern climate zone of Yanzhou, which is now modern day Yan'an, Shaanxi province. Previous Chinese authors also presented ideas about changing landforms. Scholar-official Du Yu (222–285) of the Western Jin dynasty predicted that two monumental stelae recording his achievements, one buried at the foot of a mountain and the other erected at the top, would eventually change their relative positions over time as would hills and valleys. Daoist alchemist Ge Hong (284–364) created a fictional dialogue where the immortal Magu explained that the territory of the East China Sea was once a land filled with mulberry trees.
Early modern geomorphology
The term geomorphology seems to have been first used by Laumann in an 1858 work written in German. Keith Tinkler has suggested that the word came into general use in English, German and French after John Wesley Powell and W. J. McGee used it during the International Geological Conference of 1891. John Edward Marr in his The Scientific Study of Scenery considered his book as, 'an Introductory Treatise on Geomorphology, a subject which has sprung from the union of Geology and Geography'.
An early popular geomorphic model was the geographical cycle or cycle of erosion model of broad-scale landscape evolution developed by William Morris Davis between 1884 and 1899. It was an elaboration of the uniformitarianism theory that had first been proposed by James Hutton (1726–1797). With regard to valley forms, for example, uniformitarianism posited a sequence in which a river runs through a flat terrain, gradually carving an increasingly deep valley, until the side valleys eventually erode, flattening the terrain again, though at a lower elevation. It was thought that tectonic uplift could then start the cycle over. In the decades following Davis's development of this idea, many of those studying geomorphology sought to fit their findings into this framework, known today as "Davisian". Davis's ideas are of historical importance, but have been largely superseded today, mainly due to their lack of predictive power and qualitative nature.
In the 1920s, Walther Penck developed an alternative model to Davis's. Penck thought that landform evolution was better described as an alternation between ongoing processes of uplift and denudation, as opposed to Davis's model of a single uplift followed by decay. He also emphasised that in many landscapes slope evolution occurs by backwearing of rocks, not by Davisian-style surface lowering, and his science tended to emphasise surface process over understanding in detail the surface history of a given locality. Penck was German, and during his lifetime his ideas were at times rejected vigorously by the English-speaking geomorphology community. His early death, Davis' dislike for his work, and his at-times-confusing writing style likely all contributed to this rejection.
Both Davis and Penck were trying to place the study of the evolution of the Earth's surface on a more generalized, globally relevant footing than it had been previously. In the early 19th century, authors – especially in Europe – had tended to attribute the form of landscapes to local climate, and in particular to the specific effects of glaciation and periglacial processes. In contrast, both Davis and Penck were seeking to emphasize the importance of evolution of landscapes through time and the generality of the Earth's surface processes across different landscapes under different conditions.
During the early 1900s, the study of regional-scale geomorphology was termed "physiography". Physiography later was considered to be a contraction of "physical" and "geography", and therefore synonymous with physical geography, and the concept became embroiled in controversy surrounding the appropriate concerns of that discipline. Some geomorphologists held to a geological basis for physiography and emphasized a concept of physiographic regions while a conflicting trend among geographers was to equate physiography with "pure morphology", separated from its geological heritage. In the period following World War II, the emergence of process, climatic, and quantitative studies led to a preference by many earth scientists for the term "geomorphology" in order to suggest an analytical approach to landscapes rather than a descriptive one.
Climatic geomorphology
During the age of New Imperialism in the late 19th century European explorers and scientists traveled across the globe bringing descriptions of landscapes and landforms. As geographical knowledge increased over time these observations were systematized in a search for regional patterns. Climate emerged thus as prime factor for explaining landform distribution at a grand scale. The rise of climatic geomorphology was foreshadowed by the work of Wladimir Köppen, Vasily Dokuchaev and Andreas Schimper. William Morris Davis, the leading geomorphologist of his time, recognized the role of climate by complementing his "normal" temperate climate cycle of erosion with arid and glacial ones. Nevertheless, interest in climatic geomorphology was also a reaction against Davisian geomorphology that was by the mid-20th century considered both un-innovative and dubious. Early climatic geomorphology developed primarily in continental Europe while in the English-speaking world the tendency was not explicit until L.C. Peltier's 1950 publication on a periglacial cycle of erosion.
Climatic geomorphology was criticized in a 1969 review article by process geomorphologist D.R. Stoddart. The criticism by Stoddart proved "devastating" sparking a decline in the popularity of climatic geomorphology in the late 20th century. Stoddart criticized climatic geomorphology for applying supposedly "trivial" methodologies in establishing landform differences between morphoclimatic zones, being linked to Davisian geomorphology and by allegedly neglecting the fact that physical laws governing processes are the same across the globe. In addition some conceptions of climatic geomorphology, like that which holds that chemical weathering is more rapid in tropical climates than in cold climates proved to not be straightforwardly true.
Quantitative and process geomorphology
Geomorphology was started to be put on a solid quantitative footing in the middle of the 20th century. Following the early work of Grove Karl Gilbert around the turn of the 20th century, a group of mainly American natural scientists, geologists and hydraulic engineers including William Walden Rubey, Ralph Alger Bagnold, Hans Albert Einstein, Frank Ahnert, John Hack, Luna Leopold, A. Shields, Thomas Maddock, Arthur Strahler, Stanley Schumm, and Ronald Shreve began to research the form of landscape elements such as rivers and hillslopes by taking systematic, direct, quantitative measurements of aspects of them and investigating the scaling of these measurements. These methods began to allow prediction of the past and future behavior of landscapes from present observations, and were later to develop into the modern trend of a highly quantitative approach to geomorphic problems. Many groundbreaking and widely cited early geomorphology studies appeared in the Bulletin of the Geological Society of America, and received only few citations prior to 2000 (they are examples of "sleeping beauties") when a marked increase in quantitative geomorphology research occurred.
Quantitative geomorphology can involve fluid dynamics and solid mechanics, geomorphometry, laboratory studies, field measurements, theoretical work, and full landscape evolution modeling. These approaches are used to understand weathering and the formation of soils, sediment transport, landscape change, and the interactions between climate, tectonics, erosion, and deposition.
In Sweden Filip Hjulström's doctoral thesis, "The River Fyris" (1935), contained one of the first quantitative studies of geomorphological processes ever published. His students followed in the same vein, making quantitative studies of mass transport (Anders Rapp), fluvial transport (Åke Sundborg), delta deposition (Valter Axelsson), and coastal processes (John O. Norrman). This developed into "the Uppsala School of Physical Geography".
Contemporary geomorphology
Today, the field of geomorphology encompasses a very wide range of different approaches and interests. Modern researchers aim to draw out quantitative "laws" that govern Earth surface processes, but equally, recognize the uniqueness of each landscape and environment in which these processes operate. Particularly important realizations in contemporary geomorphology include:
1) that not all landscapes can be considered as either "stable" or "perturbed", where this perturbed state is a temporary displacement away from some ideal target form. Instead, dynamic changes of the landscape are now seen as an essential part of their nature.
2) that many geomorphic systems are best understood in terms of the stochasticity of the processes occurring in them, that is, the probability distributions of event magnitudes and return times. This in turn has indicated the importance of chaotic determinism to landscapes, and that landscape properties are best considered statistically. The same processes in the same landscapes do not always lead to the same end results.
According to Karna Lidmar-Bergström, regional geography is since the 1990s no longer accepted by mainstream scholarship as a basis for geomorphological studies.
Albeit having its importance diminished, climatic geomorphology continues to exist as field of study producing relevant research. More recently concerns over global warming have led to a renewed interest in the field.
Despite considerable criticism, the cycle of erosion model has remained part of the science of geomorphology. The model or theory has never been proved wrong, but neither has it been proven. The inherent difficulties of the model have instead made geomorphological research to advance along other lines. In contrast to its disputed status in geomorphology, the cycle of erosion model is a common approach used to establish denudation chronologies, and is thus an important concept in the science of historical geology. While acknowledging its shortcomings, modern geomorphologists Andrew Goudie and Karna Lidmar-Bergström have praised it for its elegance and pedagogical value respectively.
Processes
Geomorphically relevant processes generally fall into
(1) the production of regolith by weathering and erosion,
(2) the transport of that material, and
(3) its eventual deposition. Primary surface processes responsible for most topographic features include wind, waves, chemical dissolution, mass wasting, groundwater movement, surface water flow, glacial action, tectonism, and volcanism. Other more exotic geomorphic processes might include periglacial (freeze-thaw) processes, salt-mediated action, changes to the seabed caused by marine currents, seepage of fluids through the seafloor or extraterrestrial impact.
Aeolian processes
Aeolian processes pertain to the activity of the winds and more specifically, to the winds' ability to shape the surface of the Earth. Winds may erode, transport, and deposit materials, and are effective agents in regions with sparse vegetation and a large supply of fine, unconsolidated sediments. Although water and mass flow tend to mobilize more material than wind in most environments, aeolian processes are important in arid environments such as deserts.
Biological processes
The interaction of living organisms with landforms, or biogeomorphologic processes, can be of many different forms, and is probably of profound importance for the terrestrial geomorphic system as a whole. Biology can influence very many geomorphic processes, ranging from biogeochemical processes controlling chemical weathering, to the influence of mechanical processes like burrowing and tree throw on soil development, to even controlling global erosion rates through modulation of climate through carbon dioxide balance. Terrestrial landscapes in which the role of biology in mediating surface processes can be definitively excluded are extremely rare, but may hold important information for understanding the geomorphology of other planets, such as Mars.
Fluvial processes
Rivers and streams are not only conduits of water, but also of sediment. The water, as it flows over the channel bed, is able to mobilize sediment and transport it downstream, either as bed load, suspended load or dissolved load. The rate of sediment transport depends on the availability of sediment itself and on the river's discharge. Rivers are also capable of eroding into rock and forming new sediment, both from their own beds and also by coupling to the surrounding hillslopes. In this way, rivers are thought of as setting the base level for large-scale landscape evolution in nonglacial environments. Rivers are key links in the connectivity of different landscape elements.
As rivers flow across the landscape, they generally increase in size, merging with other rivers. The network of rivers thus formed is a drainage system. These systems take on four general patterns: dendritic, radial, rectangular, and trellis. Dendritic happens to be the most common, occurring when the underlying stratum is stable (without faulting). Drainage systems have four primary components: drainage basin, alluvial valley, delta plain, and receiving basin. Some geomorphic examples of fluvial landforms are alluvial fans, oxbow lakes, and fluvial terraces.
Glacial processes
Glaciers, while geographically restricted, are effective agents of landscape change. The gradual movement of ice down a valley causes abrasion and plucking of the underlying rock. Abrasion produces fine sediment, termed glacial flour. The debris transported by the glacier, when the glacier recedes, is termed a moraine. Glacial erosion is responsible for U-shaped valleys, as opposed to the V-shaped valleys of fluvial origin.
The way glacial processes interact with other landscape elements, particularly hillslope and fluvial processes, is an important aspect of Plio-Pleistocene landscape evolution and its sedimentary record in many high mountain environments. Environments that have been relatively recently glaciated but are no longer may still show elevated landscape change rates compared to those that have never been glaciated. Nonglacial geomorphic processes which nevertheless have been conditioned by past glaciation are termed paraglacial processes. This concept contrasts with periglacial processes, which are directly driven by formation or melting of ice or frost.
Hillslope processes
Soil, regolith, and rock move downslope under the force of gravity via creep, slides, flows, topples, and falls. Such mass wasting occurs on both terrestrial and submarine slopes, and has been observed on Earth, Mars, Venus, Titan and Iapetus.
Ongoing hillslope processes can change the topology of the hillslope surface, which in turn can change the rates of those processes. Hillslopes that steepen up to certain critical thresholds are capable of shedding extremely large volumes of material very quickly, making hillslope processes an extremely important element of landscapes in tectonically active areas.
On the Earth, biological processes such as burrowing or tree throw may play important roles in setting the rates of some hillslope processes.
Igneous processes
Both volcanic (eruptive) and plutonic (intrusive) igneous processes can have important impacts on geomorphology. The action of volcanoes tends to rejuvenize landscapes, covering the old land surface with lava and tephra, releasing pyroclastic material and forcing rivers through new paths. The cones built by eruptions also build substantial new topography, which can be acted upon by other surface processes. Plutonic rocks intruding then solidifying at depth can cause both uplift or subsidence of the surface, depending on whether the new material is denser or less dense than the rock it displaces.
Tectonic processes
Tectonic effects on geomorphology can range from scales of millions of years to minutes or less. The effects of tectonics on landscape are heavily dependent on the nature of the underlying bedrock fabric that more or less controls what kind of local morphology tectonics can shape. Earthquakes can, in terms of minutes, submerge large areas of land forming new wetlands. Isostatic rebound can account for significant changes over hundreds to thousands of years, and allows erosion of a mountain belt to promote further erosion as mass is removed from the chain and the belt uplifts. Long-term plate tectonic dynamics give rise to orogenic belts, large mountain chains with typical lifetimes of many tens of millions of years, which form focal points for high rates of fluvial and hillslope processes and thus long-term sediment production.
Features of deeper mantle dynamics such as plumes and delamination of the lower lithosphere have also been hypothesised to play important roles in the long term (> million year), large scale (thousands of km) evolution of the Earth's topography (see dynamic topography). Both can promote surface uplift through isostasy as hotter, less dense, mantle rocks displace cooler, denser, mantle rocks at depth in the Earth.
Marine processes
Marine processes are those associated with the action of waves, marine currents and seepage of fluids through the seafloor. Mass wasting and submarine landsliding are also important processes for some aspects of marine geomorphology. Because ocean basins are the ultimate sinks for a large fraction of terrestrial sediments, depositional processes and their related forms (e.g., sediment fans, deltas) are particularly important as elements of marine geomorphology.
Overlap with other fields
There is a considerable overlap between geomorphology and other fields. Deposition of material is extremely important in sedimentology. Weathering is the chemical and physical disruption of earth materials in place on exposure to atmospheric or near surface agents, and is typically studied by soil scientists and environmental chemists, but is an essential component of geomorphology because it is what provides the material that can be moved in the first place. Civil and environmental engineers are concerned with erosion and sediment transport, especially related to canals, slope stability (and natural hazards), water quality, coastal environmental management, transport of contaminants, and stream restoration. Glaciers can cause extensive erosion and deposition in a short period of time, making them extremely important entities in the high latitudes and meaning that they set the conditions in the headwaters of mountain-born streams; glaciology therefore is important in geomorphology.
See also
Bioerosion
Biogeology
Biogeomorphology
Biorhexistasy
British Society for Geomorphology
Coastal biogeomorphology
Coastal erosion
Concepts and Techniques in Modern Geography
Drainage system (geomorphology)
Erosion prediction
Geologic modelling
Geomorphometry
Geotechnics
Hack's law
Hydrologic modeling, behavioral modeling in hydrology
List of landforms
Orogeny
Physiographic regions of the world
Sediment transport
Soil morphology
Soils retrogression and degradation
Stream capture
Thermochronology
References
Further reading
Ialenti, Vincent. "Envisioning Landscapes of Our Very Distant Future" NPR Cosmos & Culture. 9/2014.
Bierman, P.R.; Montgomery, D.R. Key Concepts in Geomorphology. New York: W. H. Freeman, 2013. .
Ritter, D.F.; Kochel, R.C.; Miller, J.R.. Process Geomorphology. London: Waveland Pr Inc, 2011. .
Hargitai H., Page D., Canon-Tapia E. and Rodrigue C.M..; Classification and Characterization of Planetary Landforms. in: Hargitai H, Kereszturi Á, eds, Encyclopedia of Planetary Landforms. Cham: Springer 2015
External links
The Geographical Cycle, or the Cycle of Erosion (1899)
Geomorphology from Space (NASA)
British Society for Geomorphology
Earth sciences
Geology
Geological processes
Gravity
Physical geography
Planetary science
Seismology
Topography | Geomorphology | Astronomy | 5,620 |
32,483,058 | https://en.wikipedia.org/wiki/Broad%20Group | Broad Group is a private manufacturer of central air conditioning non-electric absorption chillers that are powered by natural gas and waste heat based in Changsha, China. It is also the parent company of Broad Sustainable Building, a prefab building company. The company was established in 1996 and exports products to over 60 countries.
History
1988–1992: The early years
Zhang Yue founded Broad in 1988, registering the company in Chenzhou, Hunan province. Using his savings of $3000, Broad developed industrial boilers based on Zhang's patented design. In the 1980s, most domestically manufactured boilers were of poor quality and had high risk of exploding, while Broad's did not.
1992–2005: Move to Changsha and rise
In 1992, the company was moved to Changsha and began manufacturing absorption chillers. At the time, the government provided incentives for non-electric chillers to relieve strain on the national electricity grid, contributing to the company's rise as it became the global leader in absorption chiller by sales in 1996; it entered the international market in 1998 and today, its sales in domestic and international markets split evenly.
In 2015, BSB built a 57-storey Mini Sky City that stands at a height of 204 m. The construction of the tower took just 19 days. The Tower was built using pre-manufactured steel modules which are also going to be used in construction of the Sky City One.
Innovations
Invented in 2009, the BSB achieves high energy efficiency and carbon reduction primarily through thermal insulation, preventing cool air from leaving indoors and hot air from coming in from outdoors when the weather is hot and vice versa when the weather is cold, and requires short construction time since parts are pre-fabricated in factories and assembled onsite. BSB has also been tested to be able to resist a 9.0 magnitude earthquake and was recommended in a United Nations Environment Program report on the rebuilding of Sichuan after its catastrophic earthquake in 2008.
Environmental record
In May 2011, Broad's founder and chairman, Zhang Yue, was awarded the Champions of the Earth Award (Entrepreneurial Vision Category) by the United Nations Environment Programme for Broad's commitment to climate change. It was one of the ten companies to be recognized by the BusinessWeek Greener China Business Awards in 2009. It was also named one of the "20 Most Admired Companies in China" in 2001, ’02, ’04, and ’05 by China's Economic Observer and Peking University.
References
External links
Official US site
Construction and civil engineering companies of China
Companies based in Changsha
Manufacturing companies established in 1988
Chinese companies established in 1988
Sustainable building
Chinese brands
Construction and civil engineering companies established in 1988 | Broad Group | Engineering | 536 |
77,892,279 | https://en.wikipedia.org/wiki/UB-311 | UB-311 is a vaccine targeting β-amyloid and hence anti-amyloid agent which is under development for the treatment of Alzheimer's disease. It is under development by Vaxxinity. Meningoencephalitis has been described as a possible side effect of the drug. As of February 2024, the drug is in phase 2 clinical trials. In May 2022, UB-311 received fast-track designation for Alzheimer's disease from the United States Food and Drug Administration (FDA).
References
External links
How a new kind of vaccine could lead to the eradication of Alzheimer's - New Scientist
Vaccines
Experimental drugs for Alzheimer's disease | UB-311 | Biology | 139 |
192,793 | https://en.wikipedia.org/wiki/Thomas%20Nagel | Thomas Nagel (; born July 4, 1937) is an American philosopher. He is the University Professor of Philosophy and Law Emeritus at New York University, where he taught from 1980 until his retirement in 2016. His main areas of philosophical interest are political philosophy, ethics and philosophy of mind.
Nagel is known for his critique of material reductionist accounts of the mind, particularly in his essay "What Is It Like to Be a Bat?" (1974), and for his contributions to liberal moral and political theory in The Possibility of Altruism (1970) and subsequent writings. He continued the critique of reductionism in Mind and Cosmos (2012), in which he argues against the neo-Darwinian view of the emergence of consciousness.
Life and career
Nagel was born on July 4, 1937, in Belgrade, Yugoslavia (now Serbia), to German Jewish refugees Carolyn (Baer) and Walter Nagel. He arrived in the US in 1939, and was raised in and around New York. He had no religious upbringing, but regards himself as a Jew.
Nagel received a Bachelor of Arts degree in philosophy from Cornell University in 1958, where he was a member of the Telluride House and was introduced to the philosophy of Ludwig Wittgenstein. He then attended the University of Oxford on a Fulbright Scholarship and received a BPhil in philosophy in 1960; there, he studied with J. L. Austin and Paul Grice. He received his Doctor of Philosophy degree in philosophy from Harvard University in 1963. At Harvard, Nagel studied under John Rawls, whom Nagel later called "the most important political philosopher of the twentieth century."
Nagel taught at the University of California, Berkeley (from 1963 to 1966) and at Princeton University (from 1966 to 1980), where he trained many well-known philosophers, including Susan Wolf, Shelly Kagan, and Samuel Scheffler, the last of whom is now his colleague at New York University.
Nagel is a fellow of the American Academy of Arts and Sciences and a corresponding fellow of the British Academy, and in 2006 was elected a member of the American Philosophical Society. He has held fellowships from the Guggenheim Foundation, the National Science Foundation, and the National Endowment for the Humanities. In 2008 he was awarded a Rolf Schock Prize for his work in philosophy, the Balzan prize, and the honorary degree of Doctor of Letters from the University of Oxford.
Philosophical work
Overview
Nagel began to publish philosophy at age 22; his career now spans over 60 years of publication. He thinks that each person, owing to their capacity to reason, instinctively seeks a unified world view, but if this aspiration leads one to believe that there is only one way to understand our intellectual commitments, whether about the external world, knowledge, or what our practical and moral reasons ought to be, one errs. For contingent, limited and finite creatures, no such unified world view is possible, because ways of understanding are not always better when they are more objective.
Like the British philosopher Bernard Williams, Nagel believes that the rise of modern science has permanently changed how people think of the world and our place in it. A modern scientific understanding is one way of thinking about the world and our place in it that is more objective than the commonsense view it replaces. It is more objective because it is less dependent on our peculiarities as the kinds of thinkers that people are. Our modern scientific understanding involves the mathematicized understanding of the world represented by modern physics. Understanding this bleached-out view of the world draws on our capacities as purely rational thinkers and fails to account for the specific nature of our perceptual sensibility. Nagel repeatedly returns to the distinction between "primary" and "secondary" qualities—that is, between primary qualities of objects like mass and shape, which are mathematically and structurally describable independent of our sensory apparatuses, and secondary qualities like taste and color, which depend on our sensory apparatuses.
Despite what may seem like skepticism about the objective claims of science, Nagel does not dispute that science describes the world that exists independently of us. His contention, rather, is that a given way of understanding a subject matter should not be regarded as better simply for being more objective. He argues that scientific understanding's attempt at an objective viewpoint—a "view from nowhere"—necessarily leaves out something essential when applied to the mind, which inherently has a subjective point of view. As such, objective science is fundamentally unable to help people fully understand themselves. In "What Is It Like to Be a Bat?" and elsewhere, he writes that science cannot describe what it is like to be a thinker who conceives of the world from a particular subjective perspective.
Nagel argues that some phenomena are not best grasped from a more objective perspective. The standpoint of the thinker does not present itself to the thinker: they are that standpoint. One learns and uses mental concepts by being directly acquainted with one's own mind, whereas any attempt to think more objectively about mentality would abstract away from this fact. It would, of its nature, leave out what it is to be a thinker, and that, Nagel believes, would be a falsely objectifying view. Being a thinker is to have a subjective perspective on the world; if one abstracts away from this perspective one leaves out what he sought to explain.
Nagel thinks that philosophers, over-impressed by the paradigm of the kind of objective understanding represented by modern science, tend to produce theories of the mind that are falsely objectifying in precisely this kind of way. They are right to be impressed—modern science really is objective—but wrong to take modern science to be the only paradigm of objectivity. The kind of understanding that science represents does not apply to everything people would like to understand.
As a philosophical rationalist, Nagel believes that a proper understanding of the place of mental properties in nature will involve a revolution in our understanding of both the physical and the mental, and that this is a reasonable prospect that people can anticipate in the near future. A plausible science of the mind will give an account of the stuff that underpins mental and physical properties in such a way that people will simply be able to see that it necessitates both of these aspects. Now, it seems to people that the mental and the physical are irreducibly distinct, but that is not a metaphysical insight, or an acknowledgment of an irreducible explanatory gap, but simply where people are at their present stage of understanding.
Nagel's rationalism and tendency to present human nature as composite, structured around our capacity to reason, explains why he thinks that therapeutic or deflationary accounts of philosophy are complacent and that radical skepticism is, strictly speaking, irrefutable. The therapeutic or deflationary philosopher, influenced by Wittgenstein's later philosophy, reconciles people to the dependence of our worldview on our "form of life". Nagel accuses Wittgenstein and American philosopher of mind and language Donald Davidson of philosophical idealism. Both ask people to take up an interpretative perspective to making sense of other speakers in the context of a shared, objective world. This, for Nagel, elevates contingent conditions of our makeup into criteria for what is real. The result "cuts the world down to size" and makes what there is dependent on what there can be interpreted to be. Nagel claims this is no better than more orthodox forms of idealism in which reality is claimed to be made up of mental items or constitutively dependent on a form supplied by the mind.
Philosophy of mind
What is it like to be a something
Nagel is probably most widely known in philosophy of mind as an advocate of the idea that consciousness and subjective experience cannot, at least with the contemporary understanding of physicalism, be satisfactorily explained with the concepts of physics. This position was primarily discussed by Nagel in one of his most famous articles: "What Is It Like to Be a Bat?" (1974). The article's title question, though often attributed to Nagel, was originally asked by Timothy Sprigge. The article was originally published in 1974 in The Philosophical Review, and has been reprinted several times, including in The Mind's I (edited by Daniel Dennett and Douglas Hofstadter), Readings in the Philosophy of Psychology (edited by Ned Block), Nagel's Mortal Questions (1979), The Nature of Mind (edited by David M. Rosenthal), and Philosophy of Mind: Classical and Contemporary Readings (edited by David J. Chalmers).
In "What Is It Like to Be a Bat?", Nagel argues that consciousness has essential to it a subjective character, a what it is like aspect. He writes, "an organism has conscious mental states if and only if there is something that it is like to be that organism—something it is like for the organism." In the 50th-anniversary republication of his article in book form, Nagel writes that he "tried to show that the irreducible subjectivity of consciousness is an obstacle to many proposed solutions to the mind-body problem." His critics have objected to what they see as a misguided attempt to argue from a fact about how one represents the world (trivially, one can only do so from one's point of view) to a false claim about the world, that it somehow has first-personal perspectives built into it. On that understanding, Nagel is a conventional dualist about the physical and the mental. This is, however, a misunderstanding: Nagel's point is that there is a constraint on what it is to possess the concept of a mental state, namely, that one be directly acquainted with it. Concepts of mental states are only made available to a thinker who can be acquainted with their own states; clearly, the possession and use of physical concepts has no corresponding constraint.
Part of the puzzlement here is because of the limitations of imagination: influenced by his Princeton colleague Saul Kripke, Nagel believes that any type identity statement that identifies a physical state type with a mental state type would be, if true, necessarily true. But Kripke argues that one can easily imagine a situation where, for example, one's C-fibres are stimulated but one is not in pain and so refute any such psychophysical identity from the armchair. (A parallel argument does not hold for genuine theoretical identities.) This argument that there will always be an explanatory gap between an identification of a state in mental and physical terms is compounded, Nagel argues, by the fact that imagination operates in two distinct ways. When asked to imagine sensorily, one imagines C-fibres being stimulated; if asked to imagine sympathetically, one puts oneself in a conscious state resembling pain. These two ways of imagining the two terms of the identity statement are so different that there will always seem to be an explanatory gap, whether or not this is the case. (Some philosophers of mind have taken these arguments as helpful for physicalism on the grounds that it exposes a limitation that makes the existence of an explanatory gap seem compelling, while others have argued that this makes the case for physicalism even more impossible as it cannot be defended even in principle.)
Nagel is not a physicalist because he does not believe that an internal understanding of mental concepts shows them to have the kind of hidden essence that underpins a scientific identity in, say, chemistry. But his skepticism is about current physics: he envisages in his most recent work that people may be close to a scientific breakthrough in identifying an underlying essence that is neither physical (as people currently think of the physical), nor functional, nor mental, but such that it necessitates all three of these ways in which the mind "appears" to us. The difference between the kind of explanation he rejects and the kind he accepts depends on his understanding of transparency: from his earliest work to his most recent Nagel has always insisted that a prior context is required to make identity statements plausible, intelligible and transparent.
Natural selection and consciousness
In his 2012 book Mind and Cosmos, Nagel argues against a materialist view of the emergence of life and consciousness, writing that the standard neo-Darwinian view flies in the face of common sense. He writes that mind is a basic aspect of nature, and that any philosophy of nature that cannot account for it is fundamentally misguided. He argues that the principles that account for the emergence of life may be teleological, rather than materialist or mechanistic. Despite Nagel's being an atheist and not a proponent of intelligent design (ID), his book was "praised by creationists", according to the New York Times. Nagel writes in Mind and Cosmos that he disagrees with both ID defenders and their opponents, who argue that the only naturalistic alternative to ID is the current reductionist neo-Darwinian model.
Nagel has argued that ID should not be rejected as non-scientific, for instance writing in 2008 that "ID is very different from creation science," and that the debate about ID "is clearly a scientific disagreement, not a disagreement between science and something else." In 2009, he recommended Signature in the Cell by the philosopher and ID proponent Stephen C. Meyer in The Times Literary Supplement as one of his "Best Books of the Year." Nagel does not accept Meyer's conclusions but endorsed Meyer's approach, and argued in Mind and Cosmos that Meyer and other ID proponents, David Berlinski and Michael Behe, "do not deserve the scorn with which they are commonly met."
Ethics
Nagel's Rawlsian approach
Nagel has been highly influential in the related fields of moral and political philosophy. Supervised by John Rawls, he has been a longstanding proponent of a Kantian and rationalist approach to moral philosophy. His distinctive ideas were first presented in the short monograph The Possibility of Altruism, published in 1970. That book seeks by reflection on the nature of practical reasoning to uncover the formal principles that underlie reason in practice and the related general beliefs about the self that are necessary for those principles to be truly applicable to us. Nagel defends motivated desire theory about the motivation of moral action. According to motivated desire theory, when a person is motivated to moral action it is indeed true that such actions are motivated, like all intentional actions, by a belief and a desire. But it is important to get the justificatory relations right: when a person accepts a moral judgment they are necessarily motivated to act. But it is the reason that does the justificatory work of justifying both the action and the desire. Nagel contrasts this view with a rival view which believes that a moral agent can only accept that they have a reason to act if the desire to carry out the action has an independent justification. An account based on presupposing sympathy would be of this kind.
The most striking claim of the book is that there is a very close parallel between prudential reasoning in one's own interests and moral reasons to act to further the interests of another person. When one reasons prudentially, for example about the future reasons that one will have, one allows the reason in the future to justify one's current action without reference to the strength of one's current desires. If a hurricane were to destroy someone's car next year, at that point they will want their insurance company to pay them to replace it: that future reason gives them a reason to take out insurance now. The strength of the reason ought not to be hostage to the strength of one's current desires. The denial of this view of prudence, Nagel argues, means that one does not really believe that one is one and the same person through time. One is dissolving oneself into distinct person-stages.
Altruistic action
This is the basis of his analogy between prudential actions and moral actions: in cases of altruistic action for another person's good that person's reasons quite literally become reasons for one if they are timeless and intrinsic reasons. Genuine reasons are reasons for anyone. Like the 19th-century moral philosopher Henry Sidgwick, Nagel believes that one must conceive of one's good as an impersonal good and one's reasons as objective reasons. That means, practically, that a timeless and intrinsic value generates reasons for anyone. A person who denies the truth of this claim is committed, as in the case of a similar mistake about prudence, to a false view of themself. In this case the false view is that one's reasons are irreducibly theirs, in a way that does not allow them to be reasons for anyone: Nagel argues this commits such a person to the view that they cannot make the same judgments about their own reasons third-personally that they can make first-personally. Nagel calls this "dissociation" and considers it a practical analogue of solipsism (the philosophical idea that only one's own mind is sure to exist). Once again, a false view of what is involved in reasoning properly is refuted by showing that it leads to a false view of people's nature.
Subjective and objective reasons
Nagel's later work on ethics ceases to place as much weight on the distinction between a person's personal or "subjective" reasons and their "objective" reasons. Earlier, in The Possibility of Altruism, he took the stance that if one's reasons really are about intrinsic and timeless values then, qua subjective reason, one can only take them to be the guise of the reasons that there really are: the objective ones. In later discussions, Nagel treats his former view as an incomplete attempt to convey the fact that there are distinct classes of reasons and values, and speaks instead of "agent-relative" and "agent-neutral" reasons. In the case of agent-relative reasons (the successor to subjective reasons), specifying the content of the reason makes essential reference back to the agent for whom it is a reason. An example of this might be: "Anyone has a reason to honor his or her parents." By contrast, in the case of agent-neutral reasons (the successor to objective reasons) specifying the content of the reason does not make any essential reference back to the person for whom it is a reason. An example of this might be: "Anyone has a reason to promote the good of parenthood."
Objective reasons
The different classes of reasons and values (i.e., agent-relative and agent-neutral) emphasized in Nagel's later work are situated within a Sidgwickian model in which one's moral commitments are thought of objectively, such that one's personal reasons and values are simply incomplete parts of an impersonal whole. The structure of Nagel's later ethical view is that all reasons must be brought into relation to this objective view of oneself. Reasons and values that withstand detached critical scrutiny are objective, but more subjective reasons and values can nevertheless be objectively tolerated. However, the most striking part of the earlier argument and of Sidgwick's view is preserved: agent-neutral reasons are literally reasons for anyone, so all objectifiable reasons become individually possessed no matter whose they are. Thinking reflectively about ethics from this standpoint, one must take every other agent's standpoint on value as seriously as one's own, since one's own perspective is just a subjective take on an inter-subjective whole; one's personal set of reasons is thus swamped by the objective reasons of all others.
World agent views
This is similar to "world agent" consequentialist views in which one takes up the standpoint of a collective subject whose reasons are those of everyone. But Nagel remains an individualist who believes in the separateness of persons, so his task is to explain why this objective viewpoint does not swallow up the individual standpoint of each of us. He provides an extended rationale for the importance to people of their personal point of view. The result is a hybrid ethical theory of the kind defended by Nagel's Princeton PhD student Samuel Scheffler in The Rejection of Consequentialism. The objective standpoint and its demands have to be balanced with the subjective personal point of view of each person and its demands. One can always be maximally objective, but one does not have to be. One can legitimately "cap" the demands placed on oneself by the objective reasons of others. In addition, in his later work, Nagel finds a rationale for so-called deontic constraints in a way Scheffler could not. Following Warren Quinn and Frances Kamm, Nagel grounds them on the inviolability of persons.
Political philosophy
The extent to which one can lead a good life as an individual while respecting the demands of others leads inevitably to political philosophy. In the Locke lectures published as the book Equality and Partiality, Nagel exposes John Rawls's theory of justice to detailed scrutiny. Once again, Nagel places such weight on the objective point of view and its requirements that he finds Rawls's view of liberal equality not demanding enough. Rawls's aim to redress, not remove, the inequalities that arise from class and talent seems to Nagel to lead to a view that does not sufficiently respect the needs of others. He recommends a gradual move to much more demanding conceptions of equality, motivated by the special nature of political responsibility. Normally, people draw a distinction between what people do and what people fail to bring about, but this thesis, true of individuals, does not apply to the state, which is a collective agent. A Rawlsian state permits intolerable inequalities and people need to develop a more ambitious view of equality to do justice to the demands of the objective recognition of the reasons of others. For Nagel, honoring the objective point of view demands nothing less.
Atheism
In Mind and Cosmos, Nagel writes that he is an atheist: "I lack the sensus divinitatis that enablesindeed compelsso many people to see in the world the expression of divine purpose as naturally as they see in a smiling face the expression of human feeling." In The Last Word, he wrote, "I want atheism to be true and am made uneasy by the fact that some of the most intelligent and well-informed people I know are religious believers. It isn't just that I don't believe in God and, naturally, hope that I'm right in my belief. It’s that I hope there is no God! I don’t want there to be a God; I don’t want the universe to be like that."
Experience itself as a good
Nagel has said, "There are elements which, if added to one's experience, make life better; there are other elements which if added to one's experience, make life worse. But what remains when these are set aside is not merely neutral: it is emphatically positive. ... The additional positive weight is supplied by experience itself, rather than by any of its consequences."
Personal life
Nagel married Doris Blum in 1954, divorcing in 1973. In 1979, he married Anne Hollander, who died in 2014.
Awards
Nagel received the 1996 PEN/Diamonstein-Spielvogel Award for the Art of the Essay for Other Minds (1995). He has also been awarded the Balzan Prize in Moral Philosophy (2008), the Rolf Schock Prize in Logic and Philosophy of the Royal Swedish Academy of Sciences (2008) and the Distinguished Achievement Award of the Mellon Foundation (2006).
Selected publications
Books
(Reprinted in 1978, Princeton University Press.)
Nagel, Thomas (2012). Mind and Cosmos: why the materialist neo-Darwinian conception of nature is almost certainly false. Oxford New York: Oxford University Press,
Articles
1959, "Hobbes's Concept of Obligation", Philosophical Review, pp. 68–83.
1959, "Dreaming", Analysis, pp. 112–6.
1965, "Physicalism", Philosophical Review, pp. 339–56.
1969, "Sexual Perversion", Journal of Philosophy, pp. 5–17 (repr. in Mortal Questions).
1969, "The Boundaries of Inner Space", Journal of Philosophy, pp. 452–8.
1970, "Death", Nous, pp. 73–80 (repr. in Mortal Questions).
1970, "Armstrong on the Mind", Philosophical Review, pp. 394–403 (a discussion review of A Materialist Theory of the Mind by D. M. Armstrong).
1971, "Brain Bisection and the Unity of Consciousness", Synthese, pp. 396–413 (repr. in Mortal Questions).
1971, "The Absurd", Journal of Philosophy, pp. 716–27 (repr. in Mortal Questions).
1972, "War and Massacre", Philosophy & Public Affairs, vol. 1, pp. 123–44 (repr. in Mortal Questions).
1973, "Rawls on Justice", Philosophical Review, pp. 220–34 (a discussion review of A Theory of Justice by John Rawls).
1973, "Equal Treatment and Compensatory Discrimination", Philosophy & Public Affairs, vol. 2, pp. 348–62.
1974, "What Is it Like to Be a Bat?", Philosophical Review, pp. 435–50 (repr. in Mortal Questions). Online text
1976, "Moral Luck", Proceedings of the Aristotelian Society Supplementary vol. 50, pp. 137–55 (repr. in Mortal Questions).
1979, "The Meaning of Equality", Washington University Law Quarterly, pp. 25–31.
1981, "Tactical Nuclear Weapons and the Ethics of Conflict", Parameters: Journal of the U.S. Army War College, pp. 327–8.
1983, "The Objective Self", in Carl Ginet and Sydney Shoemaker (eds.), Knowledge and Mind, Oxford University Press, pp. 211–232.
1987, "Moral Conflict and Political Legitimacy", Philosophy & Public Affairs, pp. 215–240.
1994, "Consciousness and Objective Reality", in R. Warner and T. Szubka (eds.), The Mind-Body Problem, Blackwell.
1995, "Personal Rights and Public Space", Philosophy & Public Affairs, vol. 24, no. 2, pp. 83–107.
1997, "Assisted Suicide: The Philosophers' Brief" (with R. Dworkin, R. Nozick, J. Rawls, T. Scanlon, and J. J. Thomson), New York Review of Books, March 27, 1997.
1998, "Reductionism and Antireductionism", in The Limits of Reductionism in Biology, Novartis Symposium 213, John Wiley & Sons, pp. 3–10.
1998, "Concealment and Exposure", Philosophy & Public Affairs, vol. 27, no. 1, pp. 3–30. Online text
1998, "Conceiving the Impossible and the Mind-Body Problem", Philosophy, vol. 73, no. 285, pp. 337–352. Online PDF
2000, "The Psychophysical Nexus", in Paul Boghossian and Christopher Peacocke (eds.) New Essays on the A Priori, Oxford: Clarendon Press, pp. 432–471. Online PDF
2003, "Rawls and Liberalism", in Samuel Freeman (ed.) The Cambridge Companion to Rawls, Cambridge University Press, pp. 62–85.
2003, "John Rawls and Affirmative Action", The Journal of Blacks in Higher Education, no. 39, pp. 82–4.
2008, "Public Education and Intelligent Design", Philosophy and Public Affairs
2009, "The I in Me", a review article of Selves: An Essay in Revisionary Metaphysics by Galen Strawson, Oxford, 448 pp, , lrb.co.uk
2021, Thomas Nagel, "Types of Intuition: Thomas Nagel on human rights and moral knowledge", London Review of Books, vol. 43, no. 11 (3 June 2021), pp. 3, 5–6, 8. Deontology, consequentialism, utilitarianism.
2023: "Leader of the Martians" (review of M.W. Rowe, J.L. Austin: Philosopher and D-Day Intelligence Officer, Oxford, May 2023, , 660 pp.), London Review of Books, vol. 45, no. 17 (7 September 2023), pp. 9–10. "I [the reviewer, Thomas Nagel] was one of Austin's last students..." (p. 10.) A quotation from J.L. Austin: "Is it not possible that the next century may see the birth... of a true and comprehensive science of language? Then we shall have rid ourselves of one more part of philosophy... in the only way we ever can get rid of philosophy, by kicking it upstairs." (p. 10.)
See also
American philosophy
List of American philosophers
New York University Department of Philosophy
David Chalmers
Frank Jackson
Galen Strawson
Hard problem of consciousness
Knowledge argument
Phenomenology
Neutral monism
References
Further reading
.
External links
1937 births
Living people
20th-century American philosophers
21st-century American philosophers
American atheists
American consciousness researchers and theorists
American people of German-Jewish descent
Analytic philosophers
Atheist philosophers
Cornell University alumni
Corresponding fellows of the British Academy
American critics of postmodernism
Harvard University alumni
Jewish American atheists
Jewish philosophers
Kantian philosophers
Members of the American Philosophical Society
Members of the European Academy of Sciences and Arts
New York University faculty
New York University School of Law faculty
Non-Darwinian evolution
PEN/Diamonstein-Spielvogel Award winners
People from Belgrade
American philosophers of mind
Princeton University faculty
Rolf Schock Prize laureates
Serbian atheists
21st-century Serbian Jews
Serbian people of German descent
Yugoslav emigrants to the United States | Thomas Nagel | Biology | 6,234 |
30,961,758 | https://en.wikipedia.org/wiki/Johannes%20Hjelmslev | Johannes Trolle Hjelmslev (; 7 April 1873 – 16 February 1950) was a mathematician from Hørning, Denmark. Hjelmslev worked in geometry and history of geometry. He was the discoverer and eponym of the Hjelmslev transformation, a method for mapping an entire hyperbolic plane into a circle with a finite radius.
He was the father of Louis Hjelmslev.
Originally named Johannes Trolle Petersen, he changed his patronymic to the surname Hjelmslev to avoid confusion with Julius Petersen. Some of his results are known under his original name, including the Petersen–Morley theorem.
Publications
Johannes Hjelmslev, Grundprinciper for den infinitesimale Descriptivgeometri med Anvendelse paa Læren om variable Figurer. Afhandling for den philosophiske Doctorgrad, 1897
Johannes Hjelmslev, Deskriptivgeometri: Grundlag for Forelæsninger paa Polyteknisk Læreanstalt, Jul. Gjellerup 1904
Johannes Hjelmslev, Geometriske Eksperimenter, Jul. Gjellerup 1913
Johannes Hjelmslev, Darstellende Geometrie, Teubner 1914
Johannes Hjelmslev, Geometrische Experimente, Teubner 1915
Johannes Hjelmslev, Lærebog i Geometri til Brug ved den Polytekniske Læreanstalt, Jul. Gjellerup 1918
Johannes Hjelmslev, Die natürliche Geometrie- vier Vorträge, Hamburger Mathematische Einzelschriften 1923
Johannes Hjelmslev, Om et af den danske matematiker Georg Mohr udgivet skrift Euclides Danicus, udkommet i Amsterdam i 1672", Matematisk Tidsskrift B, 1928, pp 1-7
Johannes Hjelmslev, Grundlagen der projektiven Geometrie, 1929
Johannes Hjelmslev, Beiträge zur Lebensbeschreibung von Georg Mohr, Det Kongelige Danske Videnskabernes Selskab, Math.-Fys. Meddelelser, Bd.11, 1931, Nr.4
Johannes Hjelmslev, Grundlag for den projektive Geometri, Gyldendal 1943
See also
Hjelmslev's theorem
References
Gottwald, Ilgauds, Schlote Lexikon bedeutender Mathematiker, Leipzig 1990
External links
Salmonsens Konversationsleksikon,
Salmonsens Konversationsleksikon,
1873 births
1950 deaths
20th-century Danish mathematicians
Geometers
People from Skanderborg Municipality
Academic staff of the University of Copenhagen
Rectors of the University of Copenhagen
Members of the Royal Society of Sciences in Uppsala | Johannes Hjelmslev | Mathematics | 632 |
1,530,689 | https://en.wikipedia.org/wiki/Complementarity%20%28physics%29 | In physics, complementarity is a conceptual aspect of quantum mechanics that Niels Bohr regarded as an essential feature of the theory. The complementarity principle holds that certain pairs of complementary properties cannot all be observed or measured simultaneously. For example, position and momentum or wave and particle properties. In contemporary terms, complementarity encompasses both the uncertainty principle and wave-particle duality.
Bohr considered one of the foundational truths of quantum mechanics to be the fact that setting up an experiment to measure one quantity of a pair, for instance the position of an electron, excludes the possibility of measuring the other, yet understanding both experiments is necessary to characterize the object under study. In Bohr's view, the behavior of atomic and subatomic objects cannot be separated from the measuring instruments that create the context in which the measured objects behave. Consequently, there is no "single picture" that unifies the results obtained in these different experimental contexts, and only the "totality of the phenomena" together can provide a completely informative description.
History
Background
Complementarity as a physical model derives from Niels Bohr's 1927 presentation in Como, Italy, at a scientific celebration of the work of Alessandro Volta 100 years previous. Bohr's subject was complementarity, the idea that measurements of quantum events provide complementary information through seemingly contradictory results. While Bohr's presentation was not well received, it did crystallize the issues ultimately leading to the modern wave-particle duality concept. The contradictory results that triggered Bohr's ideas had been building up over the previous 20 years.
This contradictory evidence came both from light and from electrons.
The wave theory of light, broadly successful for over a hundred years, had been challenged by Planck's 1901 model of blackbody radiation and Einstein's 1905 interpretation of the photoelectric effect. These theoretical models use discrete energy, a quantum, to describe the interaction of light with matter. Despite confirmation by various experimental observations, the photon theory (as it came to be called later) remained controversial until Arthur Compton performed a series of experiments from 1922 to 1924 demonstrating the momentum of light. The experimental evidence of particle-like momentum seemingly contradicted other experiments demonstrating the wave-like interference of light.
The contradictory evidence from electrons arrived in the opposite order. Many experiments by J. J. Thompson, Robert Millikan, and Charles Wilson, among others, had shown that free electrons had particle properties. However, in 1924, Louis de Broglie proposed that electrons had an associated wave and Schrödinger demonstrated that wave equations accurately account for electron properties in atoms. Again some experiments showed particle properties and others wave properties.
Bohr's resolution of these contradictions is to accept them. In his Como lecture he says: "our interpretation of the experimental material rests essentially upon the
classical concepts." Direct observation being impossible, observations of quantum effects are necessarily classical. Whatever the nature of quantum events, our only information will arrive via classical results. If experiments sometimes produce wave results and sometimes particle results, that is the nature of light and of the ultimate constituents of matter.
Bohr's lectures
Niels Bohr apparently conceived of the principle of complementarity during a skiing vacation in Norway in February and March 1927, during which he received a letter from Werner Heisenberg regarding an as-yet-unpublished result, a thought experiment about a microscope using gamma rays. This thought experiment implied a tradeoff between uncertainties that would later be formalized as the uncertainty principle. To Bohr, Heisenberg's paper did not make clear the distinction between a position measurement merely disturbing the momentum value that a particle carried and the more radical idea that momentum was meaningless or undefinable in a context where position was measured instead. Upon returning from his vacation, by which time Heisenberg had already submitted his paper for publication, Bohr convinced Heisenberg that the uncertainty tradeoff was a manifestation of the deeper concept of complementarity. Heisenberg duly appended a note to this effect to his paper, before its publication, stating:
Bohr has brought to my attention [that] the uncertainty in our observation does not arise exclusively from the occurrence of discontinuities, but is tied directly to the demand that we ascribe equal validity to the quite different experiments which show up in the [particulate] theory on one hand, and in the wave theory on the other hand.
Bohr publicly introduced the principle of complementarity in a lecture he delivered on 16 September 1927 at the International Physics Congress held in Como, Italy, attended by most of the leading physicists of the era, with the notable exceptions of Einstein, Schrödinger, and Dirac. However, these three were in attendance one month later when Bohr again presented the principle at the Fifth Solvay Congress in Brussels, Belgium. The lecture was published in the proceedings of both of these conferences, and was republished the following year in Naturwissenschaften (in German) and in Nature (in English).
In his original lecture on the topic, Bohr pointed out that just as the finitude of the speed of light implies the impossibility of a sharp separation between space and time (relativity), the finitude of the quantum of action implies the impossibility of a sharp separation between the behavior of a system and its interaction with the measuring instruments and leads to the well-known difficulties with the concept of 'state' in quantum theory; the notion of complementarity is intended to capture this new situation in epistemology created by quantum theory. Physicists F.A.M. Frescura and Basil Hiley have summarized the reasons for the introduction of the principle of complementarity in physics as follows:
Debate following the lectures
Complementarity was a central feature of Bohr's reply to the EPR paradox, an attempt by Albert Einstein, Boris Podolsky and Nathan Rosen to argue that quantum particles must have position and momentum even without being measured and so quantum mechanics must be an incomplete theory. The thought experiment proposed by Einstein, Podolsky and Rosen involved producing two particles and sending them far apart. The experimenter could choose to measure either the position or the momentum of one particle. Given that result, they could in principle make a precise prediction of what the corresponding measurement on the other, faraway particle would find. To Einstein, Podolsky and Rosen, this implied that the faraway particle must have precise values of both quantities whether or not that particle is measured in any way. Bohr argued in response that the deduction of a position value could not be transferred over to the situation where a momentum value is measured, and vice versa.
Later expositions of complementarity by Bohr include a 1938 lecture in Warsaw and a 1949 article written for a festschrift honoring Albert Einstein. It was also covered in a 1953 essay by Bohr's collaborator Léon Rosenfeld.
Mathematical formalism
For Bohr, complementarity was the "ultimate reason" behind the uncertainty principle. All attempts to grapple with atomic phenomena using classical physics were eventually frustrated, he wrote, leading to the recognition that those phenomena have "complementary aspects". But classical physics can be generalized to address this, and with "astounding simplicity", by describing physical quantities using non-commutative algebra. This mathematical expression of complementarity builds on the work of Hermann Weyl and Julian Schwinger, starting with Hilbert spaces and unitary transformation, leading to the theorems of mutually unbiased bases.
In the mathematical formulation of quantum mechanics, physical quantities that classical mechanics had treated as real-valued variables become self-adjoint operators on a Hilbert space. These operators, called "observables", can fail to commute, in which case they are called "incompatible":
Incompatible observables cannot have a complete set of common eigenstates; there can be some simultaneous eigenstates of and , but not enough in number to constitute a complete basis. The canonical commutation relation
implies that this applies to position and momentum. In a Bohrian view, this is a mathematical statement that position and momentum are complementary aspects. Likewise, an analogous relationship holds for any two of the spin observables defined by the Pauli matrices; measurements of spin along perpendicular axes are complementary. The Pauli spin observables are defined for a quantum system described by a two-dimensional Hilbert space; mutually unbiased bases generalize these observables to Hilbert spaces of arbitrary finite dimension. Two bases and for an -dimensional Hilbert space are mutually unbiased when
Here the basis vector , for example, has the same overlap with every ; there is equal transition probability between a state in one basis and any state in the other basis. Each basis corresponds to an observable, and the observables for two mutually unbiased bases are complementary to each other. This leads to the description of complementarity as a statement about quantum kinematics:
The concept of complementarity has also been applied to quantum measurements described by positive-operator-valued measures (POVMs).
Continuous complementarity
While the concept of complementarity can be discussed via two experimental extremes, continuous tradeoff is also possible.
In 1979 Wooters and Zurek introduced an information-theoretic treatment of the double-slit experiment providing on approach to a quantiative model of complementarity.
The wave-particle relation, introduced by Daniel Greenberger and Allaine Yasin in 1988, and since then refined by others, quantifies the trade-off between measuring particle path distinguishability, , and wave interference fringe visibility, :
The values of and can vary between 0 and 1 individually, but any experiment that combines particle and wave detection will limit one or the other, or both. The detailed definition of the two terms vary among applications, but the relation expresses the verified constraint that efforts to detect particle paths will result in less visible wave interference.
Modern role
While many of the early discussions of complementarity discussed hypothetical experiments, advances in technology have allowed advanced tests of this concept. Experiments like the quantum eraser verify the key ideas in complementarity; modern exploration of quantum entanglement builds directly on complementarity:
In his Nobel lecture, physicist Julian Schwinger linked complementarity to quantum field theory:
The Consistent histories interpretation of quantum mechanics takes a generalized form of complementarity as a key defining postulate.
See also
Copenhagen interpretation
Canonical coordinates
Conjugate variables
Interpretations of quantum mechanics
Wave–particle duality
References
Further reading
Berthold-Georg Englert, Marlan O. Scully & Herbert Walther, Quantum Optical Tests of Complementarity, Nature, Vol 351, pp 111–116 (9 May 1991) and (same authors) The Duality in Matter and Light Scientific American, pg 56–61, (December 1994).
Niels Bohr, Causality and Complementarity: supplementary papers edited by Jan Faye and Henry J. Folse. The Philosophical Writings of Niels Bohr, Volume IV. Ox Bow Press. 1998.
External links
Discussions with Einstein on Epistemological Problems in Atomic Physics
Einstein's Reply to Criticisms
Quantum mechanics
Niels Bohr
Dichotomies
Scientific laws | Complementarity (physics) | Physics,Mathematics | 2,302 |
70,147,600 | https://en.wikipedia.org/wiki/Stray%20cattle%20in%20India | India has over 5 million stray cattle according to the livestock census data released in January 2020. The stray cow attacks on humans and crops in both urban and rural areas is an issue for the residents.
Cow slaughter is banned in many places in India with penalties of long imprisonment and huge fines. Fear of arrest, persecution, and lynching by cow vigilantes has reduced the trading of cows. Once a cow stops giving milk, feeding and maintenance of the cow becomes a financial burden on the farmer who cannot afford their upkeep. Cattle that farmers are unable to sell are eventually abandoned. A cow is considered "stray" when its owner no longer claims ownership or its owner cannot be determined.
Stray cattle are a nuisance to traffic in urban areas and cause road accidents. The problem of solid waste pollution, especially plastic pollution and garbage dumped at public places, poses a risk to stray cattle which feed on garbage.
Causes
Slaughtering cows is illegal in most of India, because cows are considered holy in Hinduism. The anti-slaughter laws were not strictly enforced until 2014, when the Bharatiya Janata Party (BJP) came to power. Before this, farmers regularly took their old cows to slaughterhouses. Since 2014, cow slaughter has been made illegal in 18 states in India including Uttar Pradesh. In Uttar Pradesh, many slaughterhouses were closed down by the BJP state government, in accordance with the party's right wing Hindu agenda.
Growing mechanization in the farming industry has also put cattle out of use as working animals, and increased the number of cattle abandonment cases. Fear of arrest, persecution, and lynching by cow vigilantes has also reduced the trading of cattle. Once a cow stops giving milk, feeding and maintenance of the cow becomes a financial burden on the farmer who cannot afford their upkeep. Cattle that farmers are unable to sell are eventually abandoned to wander.
Impact
Stray cattle pose a number of threats to human residents and animal welfare in both urban and rural areas. Stray cattle have been known to feed on standing crops and attack humans.
Airports
Stray animals are common on the runways of Indian airports. These stray animals, including cattle, pose a major threat to air safety in most airports across the nation. According to Airports Authority of India (AAI) officials, animals straying onto a runway are routine at many airports in India.
In 2018, a stray cow on a runway caused chaos at Ahmedabad airport leading to two planes aborting their landings. The cow crept past security at a cargo gate at the Sardar Vallabhbhai Patel International Airport, in Ahmedabad, resulting in a cargo plane being diverted to Mumbai and delaying five domestic flights and several departures. It took over 90 minutes for the security personnel to clear the runway.
Railway
In 2019, Vinay Kumar, the Uttar Pradesh vice-president of the farmers union, Bharatiya Kisan Union, had said "Cows are roaming in the open because there is no buyer and the promised gaushalas [cow shelters] are not operational. They are also destroying crops. Farmers chase them out of their fields. Railway lines are near fields, and the cattle go to open areas near the railway lines; some, unfortunately, come under a train."
The lack of adequate number of cowsheds (gaushalas) and the strict slaughter and trading laws were reported by The Wire as the main reasons for increase in cows roaming around and causing more cow related incidents in comparison to earlier years.
The Wire reported citing internal Indian Railways data, that in 2019 around 70 to 80 cattle were hit by trains in India daily. In 2014–2015 the number of cattle that were killed due to being overrun by trains was 2000 to 3000. It increased to 14,000 in 2017–2018. In the year 2018–2019 the number had increased to nearly 30,000, a record jump. It had become "a cause of deep concern for railway authorities".
All cases of cattle colliding with the trains do not end with the death of the cattle or the derailment of the train. According to Indian Railway data, about 18,900 trains were 'cattle-hit' in 2017–2018. The cases increased and around 43,000 trains were 'cattle-hit' in 2018–2019. In the period between April–May 2019, about 5,500 'cattle run over' (CRO) cases were recorded on the tracks, which affected the running of over 7,000 trains in two months. In August 2018, Indian Express reported a 362% jump in CRO cases from 2015-16 to 2017-2018.
In February 2019, at Etawah in Uttar Pradesh, the newly-launched Vande Bharat Express on its second day of service, had hit a stray cow. The aerodynamic nose of the train, made of steel with a fibre cover on it was damaged. Similar incident happened again on 17 August 2019.
According to railway officials, 'cattle run over' events disrupt operations for several hours, as the carcass must first be cleared from the track before the train can proceed. Fencing of the railway lines with concrete reinforced barbed wire have been suggested to reduce the incidents.
Roads
Stray cows are a frequent cause of road accidents in cities, where they crowd roads. Cow attacks on pedestrians and vehicles often become deadly. Stationary cows on the road are a cause of frequent deadly road accidents in India. Cattle dung also creates a road hazard for pedestrians and two-wheeled vehicles who may slip on it.
In Tiruvallur, in 2022, emergency braking by a semi truck driver to avoid a collision with stray cattle on the road caused a multiple-vehicle collision which killed one driver. Most of the accidents related to stray cattle on the roads occur at night, when it is harder to see the animal on roads with insufficient lights.
Historian, D. N. Jha had said, "In Delhi, cows should best be treated as a safety hazard. You cannot drive safely for the cows that stray around."
Election issue
The deadly attacks by stray cows were an election issue in the 2022 Uttar Pradesh Legislative Assembly election. In 2017, after coming to power in Uttar Pradesh, the Yogi Adityanath ministry promised to build cattle shelters to better manage the stray cattle. Since then, anti-cow-slaughter laws have been strictly enforced.
The main opposition party in 2021, Samajwadi Party (SP), promised compensation of for farmers who were killed by bulls. SP promised to fix the root cause of the problem, removing the risk of trouble or harassment from the trading of livestock.
In 2022, BJP leaders denied that stray cattle was an issue, despite complaints from farmers that stray cattle were destroying crops. Speaking at a rally in Kanpur in February 2022, PM Narendra Modi acknowledged the issue in his rally and said that the Yogi government was trying to solve the problem by setting up cattle shelters.
On 22 February, local farmers released hundreds of cattle at the venue of an election rally in Barabanki located 40 km from the state capital, Lucknow. The act was to highlight the issues caused by the stray cattle in the area. In a viral video of the incident, hundreds of unattended cattle were seen roaming in the open rally ground.
Governmental response
Laws
In June 2020, the Uttar Pradesh government approved the Uttar Pradesh Cabinet Cow Slaughter Prevention (Amendment) Ordinance, 2020, that provided maximum sentences of 10 years imprisonment and fines of up to for cow slaughter.
The residents of Tiruvallur district who allow their cattle to freely wander on the roads have been warned by the police. Imprisonment of up to three years and fines up to ₹5,000 are applicable according to the provisions of the Tamil Nadu Animals and Birds in Urban Areas (Control and Regulation) Act, 1997. Police have also threatened actions according to the Indian Penal Code and Prevention of Cruelty to Animals Act, in addition the stray cattle would be sent to cow sheds operated by the government. Yet these measures have not reduced the practice of cattle owners releasing their cattle. The authorities of Tiruvallur district have also set up a call center to report incidents of stray cattle.
Cow tax
The Adityanath ministry in the state of Uttar Pradesh introduced a special 0.5% tax named the "Cow Protection Cess" on eight government departments including the department that earns revenue from alcohol taxes. The cow protection cess was levied to earn money and maintain thousands of cow sheds operated by the government. The BBC reported that the tax did not solve the problem of stray cows, and the cow sheds were found to be overcrowded. In 2019, there were 510 cow shelters in the state of Uttar Pradesh registered in the state government records.
In 2021, it was reported that the Ludhiana Municipal Corporation had collected a cow cess of ₹3.5 crore every year, for taking care of stray cows. However, as of 2021, hundreds of stray cows were seen roaming in the streets on public places in Ludhiana city.
Cow sheds
Goshalas ('cow sheds') are shelters for unproductive, homeless, unwanted or elderly cattle in India. Since the BJP government came into power in India in 2014, India has spent on cow shelters in between the years 2014 and 2016.
The BJP state government claims to have provided money to the village pradhans to set up cow shelters to keep the stray cattle. The Deccan Herald reported that it could not find cattle shelters in the villages of Sitapur, Lakhimpur Kheri, Hardoi and Unnao districts. Places that had cow shelters, were already full with no capacity to keep more cattle.
Large scale corruption has been reported in the building and management of cow shelters in Uttar Pradesh and Madhya Pradesh. The contracts for the cow shelters were awarded to people associated with the ruling party, BJP, or the Rashtriya Swayamsewak Sangh.
Cattle housed in the cow shelters often starve to death due to lack of fodder, in shelters that are not maintained properly. Overcrowded shelters lack sufficient manpower to manage the large number of cows and the money allotted to feed the cattle is not sufficient due to the over crowding.
See also
Maverick (animal)
References
External links
Human–animal interaction
Feral cattle
Animal welfare and rights in India
Animals in politics | Stray cattle in India | Biology | 2,089 |
14,009,844 | https://en.wikipedia.org/wiki/SMK%20box%20riboswitch | The SMKbox riboswitch (also known as SAM-III) is an RNA element that regulates gene expression in bacteria. The SMK box riboswitch is found in the 5' UTR of the MetK gene in lactic acid bacteria. The structure of this element changes upon binding to S-adenosyl methionine (SAM) to a conformation that blocks the shine-dalgarno sequence and blocks translation of the gene.
There are other known SAM-binding riboswitches such as SAM-I and SAM-II, but these appear to share no similarity in sequence or structure to SAM-III.
Structure
The crystal structure of the riboswitch from E. faecalis was solved by X-ray crystallography. The structure showed that the most conserved nucleotides involved in SAM binding were organised around a junction between three helices. In some species there are large insertions of up to 210 nucleotides within this structure.
See also
SAH riboswitch
SAM-I riboswitch
SAM-II riboswitch
SAM-IV riboswitch
SAM-V riboswitch
SAM-VI riboswitch
SAM-Chlorobi RNA motif
SAM–SAH riboswitch
References
External links
Cis-regulatory RNA elements
Riboswitch | SMK box riboswitch | Chemistry | 277 |
26,962,351 | https://en.wikipedia.org/wiki/Pleurotus%20djamor | Pleurotus djamor, commonly known as the pink oyster mushroom, is a species of fungus in the family Pleurotaceae.
Taxonomy
It was originally named Boletus secundus arboreus by the German-born botanist Georg Eberhard Rumphius, in 1750. It was sanctioned under the name Agaricus djamor by Elias Magnus Fries in 1821, before he transferred the species to the genus Lentinus. It was transferred to the genus Pleurotus by Karel Bernard Boedijn in 1959.
Description
Macroscopic characteristics
The pink oyster mushroom has a pink color, though there are also white forms. It has a fan-shaped, broadly convex to plane cap which is 2– 5 cm broad and 3-7 cm long, with an inrolled margin. The gills range from light pink to cream, and are 0.5-0.7 μm in width. The stem is white with matted hairs and is very short or non existent.
The flavor of the pink oyster mushroom has been described as meaty and fishy. Just like most mushrooms, it is quite umami. Its texture is both meaty and chewy. When fried until crispy, it resembles bacon or even ham. However, when it is raw, it has a sour taste.
The reason why it is very rare to find in supermarkets is that it has a shelf life of only about a day. Since it is only harvested from spring to fall, it is only available during that time.
Microscopic characteristics
The spore print is pink, and the spores are inamyloid and ellipsoid. They measure 7-8 ×3-4.5 μm.The basidia measure 24.93-25.26 x 6.7-7.4 μm and have 4 spores each. The sterigmata are 1.5-1.75 μm in size. Clamp connections are present.
Ecology and distribution
The pink oyster mushroom grows in tropical and subtropical areas, growing as far north as Japan and as far south as New Zealand. In Hawai'i, pink oyster mushrooms often grow on fallen coconuts, and on the stalks of palm fronds, though they can also be found on fallen ōhiʻa branches in the forests of the Hawaiian island Kaua'i.
Uses And benefits
Pink oyster mushrooms are best suited for cooked applications such as sautéing, boiling, roasting, or frying. They can be sautéed or stir-fried with other vegetables, added to pasta dishes, sprinkled on top of pizza, added to grain bowls, sautéed with eggs, boiled in soups, chowders, or stews, or cooked into risotto. They can also be sautéed and mixed with cream-based white sauces for added flavor. Due to their meaty texture, these mushrooms require thorough cooking to develop their flavor and an edible consistency.
Pink oyster mushrooms are widely cultivated. They require less water spraying during fruiting than the Italian oyster. They also don't require as high a temperature as other oyster mushrooms, fruiting well at only 18-20°C. They can be cultivated on barley straw, sawdust, tea leaves and wheat straw.
Pink oyster mushrooms contain high levels of vitamin C and potassium compared to other mushrooms. it also contains 74 percentage of Nutrition
Cultural significance
Pink oyster mushrooms are a commonly found specimen in central Mexican communities. It is the most well known mushroom in Tlayacapan, Morelos, with 98.8% of surveyed locals being able to identify it. The species is collected by families and then often sold at vendors markets. Locals call it a variety of names: "seta", "cazahuate", "orejón", "hongo de pino", "blanco", "oreja de cazahuate". Pink oyster mushrooms are also sold, door-to-door by mestizos in mountainous communities, such as San Lorenzo de Atzqueltán and Izolta.
See also
List of Pleurotus species
References
External links
Edible fungi
Fungi described in 1821
Pleurotaceae
Fungus species | Pleurotus djamor | Biology | 850 |
37,268,040 | https://en.wikipedia.org/wiki/Thiofanox | Thiofanox is a chemical compound used in acaricides and insecticides.
References
External links
Acetylcholinesterase inhibitors
Insecticides
Acaricides
Carbamate insecticides
Oxime carbamates
Tert-butyl compounds | Thiofanox | Chemistry | 52 |
498,127 | https://en.wikipedia.org/wiki/Aldol%20reaction | The aldol reaction (aldol addition) is a reaction in organic chemistry that combines two carbonyl compounds (e.g. aldehydes or ketones) to form a new β-hydroxy carbonyl compound. Its simplest form might involve the nucleophilic addition of an enolized ketone to another:
These products are known as aldols, from the aldehyde + alcohol, a structural motif seen in many of the products. The use of aldehyde in the name comes from its history: aldehydes are more reactive than ketones, so that the reaction was discovered first with them.
The aldol reaction is paradigmatic in organic chemistry and one of the most common means of forming carbon–carbon bonds in organic chemistry. It lends its name to the family of aldol reactions and similar techniques analyze a whole family of carbonyl α-substitution reactions, as well as the diketone condensations.
Scope
Aldol structural units are found in many important molecules, whether naturally occurring or synthetic. The reaction is well used on an industrial scale, notably of pentaerythritol, trimethylolpropane, the plasticizer precursor 2-ethylhexanol, and the drug Lipitor (atorvastatin, calcium salt). For many of the commodity applications, the stereochemistry of the aldol reaction is unimportant, but the topic is of intense interest for the synthesis of many specialty chemicals.
Aldol dimerization
In its simplest implementation, base induces conversion of an aldehyde or a ketone to the aldol product. One example involves the aldol condensation of propionaldehyde:
Featuring the RCH(OH)CHR'C(O)R" grouping, the product is an aldol. In this case {{chem2|R = CH3CH2, R' = CH3, and R = H}}. Such reactions are called aldol aldol dimerization.
Cross-aldol
With a mixture of carbonyl precursors, complicated mixtures can occur. Addition of base to a mixture of propionaldehyde and acetaldehyde, one obtains four products:
The first two products are the result of aldol dimerization but the latter two result from a crossed aldol reaction. Complicated mixtures from cross aldol reactions can be avoided by using one component that cannot form an enolate, examples being formaldehyde and benzaldehyde. This approach is used in one stage in the production of trimethylolethane, which entails crossed aldol condensation of butyraldehyde and formaldehyde:
Reactions of aldols
Aldols dehydrate:
Because this conversion is facile, it is sometimes assumed. It is for this reason that the aldol reaction is sometimes called the aldol condensation.
Mechanisms
The aldol reaction has one underlying mechanism: a carbanion-like nucleophile attacks a carbonyl center.
If the base is of only moderate strength such as hydroxide ion or an alkoxide, the aldol reaction occurs via nucleophilic attack by the resonance-stabilized enolate on the carbonyl group of another molecule. The product is the alkoxide salt of the aldol product. The aldol itself is then formed, and it may then undergo dehydration to give the unsaturated carbonyl compound. The scheme shows a simple mechanism for the base-catalyzed aldol reaction of an aldehyde with itself.
Although only a catalytic amount of base is required in some cases, the more usual procedure is to use a stoichiometric amount of a strong base such as LDA or NaHMDS. In this case, enolate formation is irreversible, and the aldol product is not formed until the metal alkoxide of the aldol product is protonated in a separate workup step.
When an acid catalyst is used, the initial step in the reaction mechanism involves acid-catalyzed tautomerization of the carbonyl compound to the enol. The acid also serves to activate the carbonyl group of another molecule by protonation, rendering it highly electrophilic. The enol is nucleophilic at the α-carbon, allowing it to attack the protonated carbonyl compound, leading to the aldol after deprotonation. Some may also dehydrate past the intended product to give the unsaturated carbonyl compound through aldol condensation.
Crossed-aldol reactant control
Despite the attractiveness of the aldol manifold, there are several problems that need to be addressed to render the process effective. The first problem is a thermodynamic one: most aldol reactions are reversible. Furthermore, the equilibrium is also just barely on the side of the products in the case of simple aldehyde–ketone aldol reactions. If the conditions are particularly harsh (e.g.: NaOMe/MeOH/reflux), condensation may occur, but this can usually be avoided with mild reagents and low temperatures (e.g., LDA (a strong base), THF, −78 °C). Although the aldol addition usually proceeds to near completion under irreversible conditions, the isolated aldol adducts are sensitive to base-induced retro-aldol cleavage to return starting materials. In contrast, retro-aldol condensations are rare, but possible. This is the basis of the catalytic strategy of class I aldolases in nature, as well as numerous small-molecule amine catalysts.
When a mixture of unsymmetrical ketones are reacted, four crossed-aldol (addition) products can be anticipated: Thus, if one wishes to obtain only one of the cross-products, one must control which carbonyl becomes the nucleophilic enol/enolate and which remains in its electrophilic carbonyl form.
The simplest control is if only one of the reactants has acidic protons, and only this molecule forms the enolate. For example, the addition of diethyl malonate into benzaldehyde produces only one product:
If one group is considerably more acidic than the other, the most acidic proton is abstracted by the base and an enolate is formed at that carbonyl while the less-acidic carbonyl remains electrophilic. This type of control works only if the difference in acidity is large enough and base is the limiting reactant. A typical substrate for this situation is when the deprotonatable position is activated by more than one carbonyl-like group. Common examples include a CH2 group flanked by two carbonyls or nitriles (see for example the Knoevenagel condensation and the first steps of the malonic ester synthesis and acetoacetic ester synthesis).
Otherwise, the most acidic carbonyls are typically also the most active electrophiles: first aldehydes, then ketones, then esters, and finally amides. Thus cross-aldehyde reactions are typically most challenging because they can polymerize easily or react unselectively to give a statistical mixture of products.
One common solution is to form the enolate of one partner first, and then add the other partner under kinetic control. Kinetic control means that the forward aldol addition reaction must be significantly faster than the reverse retro-aldol reaction. For this approach to succeed, two other conditions must also be satisfied; it must be possible to quantitatively form the enolate of one partner, and the forward aldol reaction must be significantly faster than the transfer of the enolate from one partner to another. Common kinetic control conditions involve the formation of the enolate of a ketone with LDA at −78 °C, followed by the slow addition of an aldehyde.
Stereoselectivity
The aldol reaction unites two relatively simple molecules into a more complex one. Increased complexity arises because each end of the new bond may become a stereocenter. Modern methodology has not only developed high-yielding aldol reactions, but also completely controls both the relative and absolute configuration of these new stereocenters.
To describe relative stereochemistry at the α- and β-carbon, older papers use saccharide chemistry's erythro/threo nomenclature; more modern papers use the following syn/anti convention. When propionate (or higher order) nucleophiles add to aldehydes, the reader visualizes the R group of the ketone and the R group of the aldehyde aligned in a "zig zag" pattern on the paper (or screen). The disposition of the formed stereocenters is deemed syn or anti, depending if they are on the same or opposite sides of the main chain:
The principal factor determining an aldol reaction's stereoselectivity is the enolizing metal counterion. Shorter metal-oxygen bonds "tighten" the transition state and effects greater stereoselection. Boron is often used because its bond lengths are significantly shorter than other cheap metals (lithium, aluminium, or magnesium). The following reaction gives a syn:anti ratio of 80:20 using a lithium enolate compared to 97:3 using a bibutylboron enolate.
Where the counterion determines stereoinduction strength, the enolate isomer determines its direction. E isomers give anti products and Z give syn:
Zimmermann-Traxler model
If the two reactants have carbonyls adjacent to a pre-existing stereocenter, then the new stereocenters may form at a fixed orientation relative to the old. This "substrate-based stereocontrol" has seen extensive study and examples pervade the literature. In many cases, a stylized transition state, called the Zimmerman–Traxler model, can predict the new orientation from the configuration of a 6-membered ring.
On the enol
If the enol has an adjacent stereocenter, then the two stereocenters flanking the carbonyl in the product are naturally syn:
The underlying mechanistic reason depends on the enol isomer. For an E enolate, the stereoinduction is necessary to avoid 1,3-allylic strain, while a Z enolate instead seeks to avoid 1,3-diaxial interactions:
However, Fráter & Seebach showed that a chelating Lewis basic moiety adjacent to the enol will instead cause anti addition.
On the electrophile
E enolates exhibit Felkin diastereoface selection, while Z enolates exhibit anti-Felkin selectivity. The general model is presented below:
Since the transition state for Z enolates must contain either a destabilizing syn-pentane interaction or an anti-Felkin rotamer, Z-enolates are less diastereoselective:
On both
If both the enolate and the aldehyde contain pre-existing chirality, then the outcome of the "double stereodifferentiating" aldol reaction may be predicted using a merged stereochemical model that takes into account all the effects discussed above. Several examples are as follows:
Oxazolidinone chiral auxiliaries
In the late 1970s and 1980s, David A. Evans and coworkers developed a technique for stereoselection in the aldol syntheses of aldehydes and carboxylic acids.Gage J. R.; Evans D. A., Diastereoselective Aldol Condensation Using A Chiral Oxazolidinone Auxiliary: (2S*,3S*)-3-Hydroxy-3-Phenyl-2-Methylpropanoic Acid , Organic Syntheses, Coll. Vol. 8, p.339 (1993); Vol. 68, p.83 (1990). The method works by temporarily appending a chiral oxazolidinone auxiliary to create a chiral enolate. The pre-existing chirality from the auxiliary is then transferred to the aldol adduct through Zimmermann-Traxler methods, and then the oxazolidinone cleaved away.
Commercial oxazolidinones are relatively expensive, but derive in 2 synthetic steps from comparatively inexpensive amino acids. (Economical large-scale syntheses prepare the auxiliary in-house.) First, a borohydride reduces the acid moiety. Then the resulting amino alcohol dehydratively cyclises with a simple carbonate ester, such as diethylcarbonate.
The acylation of an oxazolidinone is informally referred to as "loading done".
Anti adducts, which require an E enolate, cannot be obtained reliably with the Evans method. However, Z enolates, leading to syn adducts, can be reliably formed using boron-mediated soft enolization:
Often, a single diastereomer may be obtained by one crystallization of the aldol adduct.
Many methods cleave the auxiliary:
Variations
A common additional chiral auxiliary is a thioether group:
Crimmins thiazolidinethione aldol
In the Crimmins thiazolidinethione' approach, a thiazolidinethione is the chiral auxiliary and can produce the "Evans syn" or "non-Evans syn" adducts by simply varying the amount of (−)-sparteine. The reaction is believed to proceed via six-membered, titanium-bound transition states, analogous to the proposed transition states for the Evans auxiliary.
"Masked" enols
A common modification of the aldol reaction uses other, similar functional groups as ersatz enols. In the Mukaiyama aldol reaction, silyl enol ethers add to carbonyls in the presence of a Lewis acid catalyst, such as boron trifluoride (as boron trifluoride etherate) or titanium tetrachloride.3-Hydroxy-3-Methyl-1-Phenyl-1-Butanone by Crossed Aldol Reaction Teruaki Mukaiyama and Koichi Narasaka Organic Syntheses, Coll. Vol. 8, p.323 (1993); Vol. 65, p.6 (1987)
In the Stork enamine alkylation, secondary amines form enamines when exposed to ketones. These enamines then react (possibly enantioselectively) with suitable electrophiles. This strategy offers simple enantioselection without transition metals. In contrast to the preference for syn adducts typically observed in enolate-based aldol additions, these aldol additions are anti-selective.
In aqueous solution, the enamine can then be hydrolyzed from the product, making it a small organic molecule catalyst. In a seminal example, proline efficiently catalyzed the cyclization of a triketone:
This combination is the Hajos-Parrish reaction Under Hajos-Parrish conditions only a catalytic amount of proline is necessary (3 mol%). There is no danger of an achiral background reaction because the transient enamine intermediates are much more nucleophilic than their parent ketone enols.
A Stork-type strategy also allows the otherwise challenging cross-reactions between two aldehydes. In many cases, the conditions are mild enough to avoid polymerization: However, selectivity requires the slow syringe-pump controlled addition of the desired electrophilic partner because both reacting partners typically have enolizable protons. If one aldehyde has no enolizable protons or alpha- or beta-branching, additional control can be achieved.
"Direct" aldol additions
In the usual aldol addition, a carbonyl compound is deprotonated to form the enolate. The enolate is added to an aldehyde or ketone, which forms an alkoxide, which is then protonated on workup. A superior method, in principle, would avoid the requirement for a multistep sequence in favor of a "direct" reaction that could be done in a single process step.
If one coupling partner preferentially enolizes, then the general problem is that the addition generates an alkoxide, which is much more basic than the starting materials. This product binds tightly to the enolizing agent, preventing it from catalyzing additional reactants:
One approach, demonstrated by Evans, is to silylate the aldol adduct. A silicon reagent such as TMSCl is added in the reaction, which replaces the metal on the alkoxide, allowing turnover of the metal catalyst:
Use in carbohydrate synthesis
Traditional syntheses of hexoses use variations of iterative protection-deprotection strategies, requiring 8–14 steps, organocatalysis can access many of the same substrates by a two-step protocol involving the proline-catalyzed dimerization of alpha-oxyaldehydes followed by tandem Mukaiyama aldol cyclization.
The aldol dimerization of alpha-oxyaldehydes requires that the aldol adduct, itself an aldehyde, be inert to further aldol reactions.
Earlier studies revealed that aldehydes bearing alpha-alkyloxy or alpha-silyloxy substituents were suitable for this reaction, while aldehydes bearing Electron-withdrawing groups such as acetoxy were unreactive. The protected erythrose product could then be converted to four possible sugars via Mukaiyama aldol addition followed by lactol formation. This requires appropriate diastereocontrol in the Mukaiyama aldol addition and the product silyloxycarbenium ion to preferentially cyclize, rather than undergo further aldol reaction. In the end, glucose, mannose, and allose were synthesized:
Biological aldol reactions
Examples of aldol reactions in biochemistry include the splitting of fructose-1,6-bisphosphate into dihydroxyacetone and glyceraldehyde-3-phosphate in the fourth stage of glycolysis, which is an example of a reverse ("retro") aldol reaction catalyzed by the enzyme aldolase A (also known as fructose-1,6-bisphosphate aldolase).
In the glyoxylate cycle of plants and some prokaryotes, isocitrate lyase produces glyoxylate and succinate from isocitrate. Following deprotonation of the OH group, isocitrate lyase cleaves isocitrate into the four-carbon succinate and the two-carbon glyoxylate by an aldol cleavage reaction. This cleavage is similar mechanistically to the aldolase A reaction of glycolysis.
History
The aldol reaction was discovered independently by the Russian chemist (and Romantic composer) Alexander Borodin in 1869Garner, Susan Amy (2007) "Hydrogen-mediated carbon-carbon bond formations: Applied to reductive aldol and Mannich reactions," Ph.D. dissertation, University of Texas (Austin), pp. 4 and 51. and by the French chemist Charles-Adolphe Wurtz in 1872, which originally used aldehydes to perform the reaction.
Howard Zimmerman and Marjorie D. Traxler proposed their model for stereoinduction in a 1957 paper.
See also
Aldol–Tishchenko reaction
Baylis–Hillman reaction
Ivanov reaction
Reformatsky reaction
Claisen-Schmidt condensation
Notes
References
Further reading
Chem 206, 215 Lecture Notes (2003, 2006) by D. A. Evans, A. G. Myers, et al.'', Harvard University (pp. 345, 936)
Addition reactions
Carbon-carbon bond forming reactions
Alexander Borodin | Aldol reaction | Chemistry | 4,150 |
524,582 | https://en.wikipedia.org/wiki/Space%20fountain | A space fountain is a proposed form of an extremely tall tower extending into space. As known materials cannot support a static tower with this height, a space fountain has to be an active structure: A stream of pellets is accelerated upwards from a ground station. At the top it is deflected downwards. The necessary force for this deflection supports the station at the top and payloads going up the structure. A spacecraft could launch from the top without having to deal with the atmosphere. This could reduce the cost of placing payloads into orbit. Its largest downside is that the tower will re-enter the atmosphere if the accelerator fails and the stream stops. This risk could be reduced by several redundant streams.
The lower part of a pellet stream has to be in a vacuum tube to avoid excessive drag in the atmosphere. Similar to the top station, this tube can be supported by its own system of transferring momentum from a space-bound stream to a surface-bound stream. If the tube itself also accelerates the station-supporting stream, it would have to transfer additional momentum to an earth-bound stream in order to keep itself supported. The tube-supporting streams could also be designed to integrate with the station-supporting streams.
Unlike a space elevator, this concept does not need extremely strong materials anywhere, and unlike space elevators and orbital rings, it does not need a long structure.
See also
Launch loop
Mass driver
Megascale engineering
Non-rocket spacelaunch
Orbital ring
Space elevator
Space gun
References
Space elevator
Exploratory engineering
Megastructures
Spaceflight technology
Vertical transport devices
Space access
Hypothetical technology | Space fountain | Astronomy,Technology | 327 |
36,366,135 | https://en.wikipedia.org/wiki/Shungite | Shungite is either a diverse group of metamorphosed Precambrian rocks all of which contain pyrobitumen, or the pyrobitumen within those rocks. It was first described from a deposit near Shunga village, in Karelia, Russia, from where it gets its name. Shungite is most widely known for pseudoscientific and quack medical claims about its uses in medicine and technology, where it is claimed to have properties ranging from nebulous health benefits to blocking 5G radiation.
Occurrence
Shungite has mainly been found in Russia. The main deposit is in the Lake Onega area of Karelia, at Zazhoginskoye, near Shunga, with another occurrence at Vozhmozero. Two other much smaller occurrences have been reported in Russia, one in Kamchatka in volcanic rocks and the other formed by the burning of spoil from a coal mine at high temperature in Chelyabinsk. Other occurrences have been described from Austria, India, Democratic Republic of Congo and Kazakhstan.
Terminology
The term "shungite" has evolved substantially since was originally used in 1879 to describe a black substance with more than 98% carbon found in veins near its type locality of Shunga. More recently the term has also been used to describe a wide variety of rocks containing similar carbon layers, leading to some confusion. In scientific usage, shungite refers to a mineraloid which contains >98% carbon, and is used as a modifier to the host-rock's name, i.e. "shungite-bearing dolostone". In popular usage, shungite-bearing rocks are sometimes themselves referred to as shungite. Shungite is subdivided into bright, semi-bright, semi-dull and dull on the basis of its lustre.
Shungite has two main modes of occurrence, disseminated within the host rock and as apparently mobilised material. Migrated shungite, which is bright (lustrous) shungite, has been interpreted to represent migrated hydrocarbons and is found as either layer shungite, layers or lenses near conformable with the host rock layering, or vein shungite, which is found as cross-cutting veins. Shungite may also occur as clasts within younger sedimentary rocks.
Formation and structure
Shungite had historically been regarded as an example of abiogenic petroleum formation, but its biological origin has now been confirmed. Non-migrated shungite is found directly stratigraphically above deposits that were formed in a shallow water carbonate shelf to non-marine evaporitic environment. The shungite-bearing sequence is thought to have been deposited during active rifting, consistent with the alkaline volcanic rocks that are found within the sequence. The organic-rich sediments were likely deposited in a brackish lagoon. The concentration of carbon indicates elevated biological productivity levels, possibly due to high levels of nutrients available from volcanic material.
Shungite-bearing deposits that retain sedimentary structures are interpreted as metamorphosed oil source rocks. Some mushroom shaped structures have been interpreted as possible mud volcanoes. Layer and vein shungite varieties, and shungite filling cavities and forming the matrix of breccias, are interpreted as migrated petroleum, now in the form of metamorphosed bitumen. Solid-bitumen shungite is predominantly amorphous, though as with many carbon deposits it contains trace amounts of carbon allotropes such as graphene sheets and fullerenes.
Shunga deposit
The Shunga deposit contains an estimated total carbon reserve of more than 250 gigatonnes. It is found within a sequence of Palaeoproterozoic meta-sedimentary and meta-volcanic rocks that are preserved in a synform. The sequence has been dated by a gabbro intrusion, which gives a date of 1980±27 Ma, and the underlying dolomites, which give an age of 2090±70 Ma. There are nine shungite-bearing layers within the Zaonezhskaya Formation, from the middle of the preserved sequence. Of these the thickest is layer six, which is also known as the "Productive horizon", due to its concentration of shungite deposits. Four main deposits are known from the area, the Shungskoe, Maksovo, Zazhogino and Nigozero deposits. The Shungskoe deposit is the most studied and is largely depleted.
Uses and pseudoscientific claims
Shungite has been used since the middle of the 18th century as a pigment for paint, and is currently sold under the names "carbon black" or "shungite natural black". In the 1970s, shungite was exploited in the production of an insulating material, known as shungisite. Shungisite is prepared by heating rocks with low shungite concentrations to and is used as a low density filler. Shungite has applications in construction technologies. The presence of fullerenes has resulted in shungite being of interest to researchers as a natural reservoir, though shungite is not uniquely enriched in fullerenes compared to other carbon-rich rocks.
Shungite has been used as a folk medical treatment since the early 18th century. Peter the Great set up Russia's first spa in Karelia to make use of the purported water purifying properties of shungite. He also instigated its use in providing purified water for the Russian army. Crystal healing pseudoscience proponents and 5G conspiracy theorists have erroneously claimed that shungite may remove 5G radiation from their vicinity more efficiently than any material of similar electrical conductivity would do. Many of these claims frequently focus on the reputed benefits of fullerenes contained in shungite, which are found in concentrations of 1 to 10 parts per million. Despite its purported health benefits, shungite contains toxic heavy metals such as lead and cadmium and can pose a health risk when used as an alternative medicine.
See also
Hydrocarbon
Oil shale
References
Geology of European Russia
Bitumen-impregnated rocks
Paleoproterozoic geology | Shungite | Chemistry | 1,258 |
3,516,055 | https://en.wikipedia.org/wiki/Nigoda | In Jain cosmology, the Nigoda is a realm existing in which the lowest forms of invisible life reside in endless numbers, and without any hope of release by self-effort. Jain scriptures describe nigodas which are microorganisms living in large clusters, having only one sense, having a very short life and are said to pervade each and every part of universe, even in tissues of plants and flesh of animals. The Nigoda exists in contrast to the Supreme Abode, also located at the Siddhashila (top of the universe) where liberated souls exist in omnisciencent and eternal bliss. According to Jain tradition, it is said that when a human being achieves liberation (Moksha) or if a human would be born as a Nigoda due to karma, another from the Nigoda is given the potential of self-effort and hope. Nigoda belongs in the lowest class of Jiva (soul).
Characteristics
The life in Nigoda is that of a sub-microscopic organism possessing only one sense, i.e., of touch.
Notes
References
Jain cosmology
Microorganisms | Nigoda | Biology | 238 |
983,463 | https://en.wikipedia.org/wiki/NGC%205078 | NGC 5078 is a spiral galaxy in the Hydra constellation, approximately 94 million light-years away from Earth. It has a diameter of 127,000 light-years and is probably a member of the NGC 5061 group. The dust lane of NGC 5078 is warped, probably by interaction with the nearby galaxy IC 879, which is itself distorted into an 'S' shape by the interaction. At the presumed distance the two galaxies would have a minimal separation of about 61,000 light-years. For comparison, the Large Magellanic Cloud is about 160,000 light-years from the Milky Way.
NGC 5078 is also only separated in the sky from the spiral galaxy NGC 5101 by about 0.5 degrees, and both are believed to be at the same distance from the Earth. This would mean they are approximately 800,000 light-years apart.
One supernova has been observed in NGC 5078: SN 1999cz (type Ic, mag. 16).
References
External links
Unbarred spiral galaxies
Hydra (constellation)
5078
46490 | NGC 5078 | Astronomy | 224 |
14,560,309 | https://en.wikipedia.org/wiki/MRGPRX3 | Mas-related G-protein coupled receptor member X3 is a protein that in humans is encoded by the MRGPRX3 gene.
See also
MAS1 oncogene
References
Further reading
G protein-coupled receptors | MRGPRX3 | Chemistry | 46 |
14,662,789 | https://en.wikipedia.org/wiki/Gusums%20Bruk | Gusums Bruk was a foundry in Gusum, Sweden, specializing in brass production. The foundry commenced operations in 1653. Chandeliers and industrial products were its main products. Cannons, copper and brass wires, button pins, candlesticks, paper fabric for fabrication, safety needles, and zippers were also made. It filed for bankruptcy and shut down in 1988. It is no longer active, and its ruins have been demolished and the area decontaminated. A former subsidiary is still in operation at another site in Gusum.
References
External links
Jornmark (site about abandoned places)
http://www.bondandbowery.com/item/13025
Foundries
Industrial buildings in Sweden
Metal companies of Sweden
1653 establishments in Sweden | Gusums Bruk | Chemistry | 153 |
6,302,572 | https://en.wikipedia.org/wiki/Hydrogen%20leak%20testing | Hydrogen leak testing is the normal way in which a hydrogen pressure vessel or installation is checked for leaks or flaws. This usually involves charging hydrogen as a tracer gas into the device undergoing testing, with any leaking gas detected by hydrogen sensors. Various test mechanisms have been devised.
Test mechanisms
Hydrostatic test
In the hydrostatic test, a vessel is filled with a nearly incompressible liquid – usually water or oil – and examined for leaks or permanent changes in shape. The test pressure is always considerably higher than the operating pressure to give a margin for safety, typically 150% of the operating pressure.
Burst test
In the burst test, a vessel is filled with a gas and tested for leaks. The test pressure is always considerably more than the operating pressure to give a margin for safety, typically 200% or more of the operating pressure.
Helium leak test
The helium leak test uses helium (the lightest inert gas) as a tracer gas and detects it in concentrations as small as one part in 10 million. The helium is selected primarily because it penetrates small leaks readily, is inert and will not react with the test piece while having a naturally low quantity in air making detection less complicated. It is possible to detect leaks as small as 5x10−10 Pa·m3/s in vacuum mode and modern digital machines can detect 5x10−10 Pa·m3/s in sniffing mode.
Vacuum test
Usually a vacuum inside the object is created with an external pump connected to the instrument. Alternatively helium can be injected inside the product while the product itself is enclosed in a vacuum chamber connected to the instrument. In this case, burst and leakage tests can be combined in one operation.
Hydrogen sensor test
During the hydrogen sensor test, the object is filled with a mixture of 5% hydrogen/ 95% nitrogen, (below 5.7% hydrogen) is non-flammable (ISO-10156). This is called typically a sniffing test. The handprobe connected to the microelectronic hydrogen sensors is used to check the object. An audiosignal increases in proximity of a leak. Detection of leaks go down to 5x10−7 cubic centimeters per second. Compared to the helium test, hydrogen is cheaper than helium, no need for a vacuum, the instrument could be cheaper but is not as sensitive as a helium leak detector so will not find smaller leaks.
Chemo-chromic hydrogen leak detectors are materials that can be proactively applied to a connection or fitting. In the event of a hydrogen leak, the chemo-chromic material changes color to alert an inspector that a leak is present. Chemo-chromic indicators can also be added to silicone tapes for hydrogen detection purposes.
See also
Hydrogen analyzer
Hydrogen piping
Hydrogen safety
Hydrogen station
Tracer-gas leak testing method
Tubing (material)
References
External links
Leakpedia – The free wiki encyclopedia about the industrial leak testing
Detectape – Hydrogen detection silicone tape
Hydrogen technologies
Tests
Hydrogen
Nondestructive testing | Hydrogen leak testing | Materials_science | 615 |
21,872,492 | https://en.wikipedia.org/wiki/Lauryldimethylamine%20oxide | Lauryldimethylamine oxide (LDAO), also known as dodecyldimethylamine oxide (DDAO), is an amine oxide–based zwitterionic surfactant, with a C12 (dodecyl) alkyl tail. It is one of the most frequently-used surfactants of this type. Like other amine oxide–based surfactants it is antimicrobial, being effective against common bacteria such as S. aureus and E. coli, however, it is also non-denaturing and can thus be used for protein purification.
At high concentrations, LDAO forms liquid crystalline phases. Despite having only one polar atom that is able to interact with water – the oxygen atom (the quaternary nitrogen atom is hidden from intermolecular interactions), DDAO is a strongly amphiphilic surfactant: it forms normal micelles and normal liquid crystalline phases. High amphiphilicity of this surfactant can be explained by the fact that it forms not only very strong hydrogen bonds with water: the energy of DDAO – water hydrogen bond is about 50 kJ/mol, but it also has high experimental partition coefficient in non-polar medium, as characterized by experimental logP 5.284
See also
Myristamine oxide – An analogous compound with a C14 tail
References
Amine oxides
Surfactants
Dodecyl compounds | Lauryldimethylamine oxide | Chemistry | 294 |
9,082,535 | https://en.wikipedia.org/wiki/Tinc%20%28protocol%29 | Tinc is an open-source, self-routing, mesh networking protocol and software implementation used for compressed and encrypted virtual private networks. It was started in 1998 by Guus Sliepen, Ivo Timmermans, and Wessel Dankers, and released as a GPL-licensed project.
Platforms
Tinc is available on Linux, FreeBSD, OpenBSD, NetBSD, DragonFly BSD, Mac OS X, Microsoft Windows, Solaris, iOS (jailbroken only), Android with full support for IPv6.
Future goals
The authors of Tinc have goals of providing a platform that is secure, stable, reliable, scalable, easily configurable, and flexible.
Embedded technologies
Tinc uses OpenSSL or LibreSSL as the encryption library and gives the options of compressing communications with zlib for "best compression" or LZO for "fast compression".
Projects that use tinc
Freifunk has tinc enabled in their routers as of October 2006.
OpenWrt has an installable package for tinc.
OPNsense, an open source router and firewall distribution, has a plugin for Tinc
pfSense has an installable package in the 2.3 release.
Tomato variants Shibby and FreshTomato include Tinc support.
NYC Mesh uses tinc to connect parts of the mesh over the public internet that would be otherwise out of range.
See also
stunnel, encrypts any TCP connection (single port service) over SSL
OpenVPN, an open source SSL VPN solution
VTUN, an open source SSL VPN solution that can bridge Ethernet
References
External links
Protocol Documentation
Internet protocols
Routing protocols
Internet Protocol based network software
Virtual private networks
Mesh networking | Tinc (protocol) | Technology | 364 |
14,575,416 | https://en.wikipedia.org/wiki/Nonanal | Nonanal is an organic compound with the chemical formula . It is one of several isomers, all are colorless oil. The nonanals are classified as aldehydes. The linear nonanal is produced commercially by the hydroformylation of 1-octene. It is used as a fragrance.
Mosquitoes
Nonanal has been identified as a compound that attracts Culex mosquitoes. Nonanal acts synergistically with carbon dioxide in that regard.
References
Fatty aldehydes
Alkanals | Nonanal | Chemistry | 106 |
73,549,670 | https://en.wikipedia.org/wiki/Nitrogen%20crisis%20in%20the%20Netherlands | The nitrogen crisis in the Netherlands () is an ecological and legal crisis that has been defined as such since 2019, following a ruling by the Administrative Jurisdiction Division of the Council of State.
Introduction
Around 78% of the earth's atmosphere is made up of gaseous nitrogen (). This naturally occurring gaseous form is fairly inert and does not pose an environmental problem. At the root of the nitrogen crisis is not but other more reactive nitrogen compounds that are the result of human impact on the nitrogen cycle. In the Netherlands, the soil is burdened by very high deposition rates of reactive nitrogen compounds, in particular ammonia (NH3) and nitrogen oxides (NOx). Ammonia is released into the air from animal manure, nitrogen oxides are emitted by internal combustion engines, such as those in motor vehicles, aircraft and industry. Nitrogen compounds from fertilizers used in agriculture are also washed directly into ground water. The presence of nitrogen compounds in large quantities is a form of nutrient pollution and adversely affects the quality of soil, water, air, and nature through the process of eutrophication.
The Netherlands emits more nitrogen compounds per hectare than any other country in the EU by a long way, according to the Netherlands Organisation for Applied Scientific Research. 61 percent of these nitrogen compounds are produced by agriculture, with intensive livestock farming being the most important source of nitrogen pollution. In a sense, the nitrogen crisis is the successor to the acid rain problem of the 1980s. Acid rain is caused by the deposition of ammonia and nitrogen oxides, but also sulfur dioxide (). From 1980 to 2020, the emission of sulfur dioxide was reduced by 80%. The emission of nitrogen compounds was also reduced by 50%. The emission of nitrogen dioxide (NO2) has been steadily decreasing ever since 1980. However, the reduction in the emission of ammonia came to a standstill around 2010, the last year of the fourth Balkenende cabinet.
In 2015, the Dutch government under the second Rutte cabinet launched a new program to reduce nitrogen pollution, the Integrated Approach to Nitrogen (, PAS).
History
2019 Court of State ruling
When the nitrogen crisis came to a head in 2019, it already had a long history, both legal and ecological. The first European standards were set as early as 1991. European Union member states are obliged to comply with the Habitats Directive, which states that a 'favourable conservation status' must be aimed for in Natura 2000 areas.
In May 2017, the Council of State submitted a number of preliminary questions to the European Court of Justice, which in November 2018 provided a further explanation of the relevant provisions of the Habitats Directive. On 29 May 2019, the Administrative Jurisdiction Division of the Council of State ruled on this basis that the government's use of the Integrated Approach to Nitrogen (PAS) was invalid when granting permits due to the anticipation of future reductions in nitrogen deposition. As a result, the PAS could no longer be used for granting nitrogen permits in the vicinity of Natura 2000 areas. This ruling led to the immediate suspension of various projects (mainly housing, which aggravated the ongoing Dutch housing shortage), and the government had to urgently seek solutions. Although nitrogen pollution had been an issue for many years, the Council of State's ruling promptly suspended an estimated 18,000 construction projects.
Later official recommendations and decisions
In June 2020, the Advisory Committee on the Nitrogen Problem under former Deputy Prime Minister Johan Remkes published a report titled ("Not Everything Is Possible Everywhere") which recommended reducing nationwide emissions of NH3 and NOx by 50% compared to 2019, for a long-term solution (up to 2030). The NH3 should be reduced even further in certain areas close to natural areas.
As of July 2021, construction projects could proceed without nitrogen testing under the so-called ("construction exemption"). However, this exemption was overturned by the Council of State in November 2022, and a "protracted nitrogen crisis" continues.
Protests and political developments
In the wake of the 2019 ruling and related government policies, a sizeable farmers' protest movement arose, which saw livestock farmers using tractors to block major Dutch roads and occupy public spaces.
In response to these protests, the agrarian and right-wing populist political party Farmer–Citizen Movement (, BBB) was founded in October 2019. In the 2021 general election, it argued for the creation of a "Ministry of the Countryside" () located at least 100 kilometers from The Hague and a removal of the ban on neonicotinoids. In addition, the party calls for right-to-farm laws, which would allow for farmers to have more say on expanding their agricultural activities, in response to local opposition to pig and goat farms over public health, environmental and agricultural concerns.
In 2023, the BBB received the most votes in the provincial elections and became the party with the largest number of seats in the Dutch Senate following the Senate election.
See also
Human impact on the nitrogen cycle
Environmental impact of agriculture
Environmental skepticism
Dutch manure crisis
References
Agriculture in the Netherlands
Environmental controversies
Environmental impact of agriculture
Environmental impact in the Netherlands
Intensive farming
Nitrogen | Nitrogen crisis in the Netherlands | Chemistry | 1,038 |
22,774,692 | https://en.wikipedia.org/wiki/Karl%20Rawer | Karl Maria Alois Rawer (19 April 1913 – 17 April 2018) was a German specialist in radio wave propagation and the ionosphere. He developed the analytical code to determine suitable frequency ranges for short wave communication by which German forces built-up their long-distance communications during World War II.
Biography
After studies of mathematics and physics in Freiburg and Munich (with Arnold Sommerfeld), under Jonathan Zenneck he wrote a thesis on partial reflection of radio waves in an ionospheric layer. Aware of this Johannes Plendl charged him to serve as adviser for the Shortwave communications of the German Luftwaffe, since 1943 for Navy and Army as well.
Rawer's code assumes zig-zag paths between Earth and ionosphere. Monthly predictions take account of day-to-day variations. Long term changes from solar cycles is taken account of by Wolfgang Gleißberg's prediction method.
After the war Yves Rocard, then director of French Navy research, was impressed by Rawer's code. He engaged him as "directeur scientifique" (1946–56) of his newly founded "Service de Prévision Ionosphérique".
Between 1956 and 1969, Rawer, serving in Germany as director of "Ionosphären-Institut Breisach" switched to space research. With his team he participated in the first French scientific rocket launch 1954 in the Sahara desert and later they experimented aboard rockets of different nationality.
From 1958 to 1964, he was "professeur associe" at the University of Paris. Rawer held several offices in the international space research organisation COSPAR. As director of "Fraunhofer-Institut für physikalische Weltraumforschung" (1969–79) he became the father of the two AEROS satellites, launched in 1972 and 1974.
He was actively engaged in the International Geophysical Year (gold button 2007) and follow-ups. In the International Union of Radio Science (URSI) he served with William Roy Piggott as co-author of the booklet on ionogram reduction and was vice-chairman and chairman of the ionospheric committee 1966–72. He was the father and longtime chairman of the International Reference Ionosphere that since 1999 is International Standard.
Rawer was doctor honoris causa of the University of Düsseldorf, corresponding member of the International Academy of Astronautics and of "Oesterreichische Akademie der Wissenschaften Wien". He died on 17 April 2018 in March, Breisgau, two days before his 105th birthday.
References
Sources
Karl Rawer: "Meine Kinder umkreisen die Erde" (autobiography). Herder, Freiburg i. Brsg., 159 S. 1986,
Bodo W. Reinisch: "Karl Rawer's lfe and the history of the IRI". Adv. Space Res. 34, 1845R 2004
Dieter Bilitza: "35 Years of International Reference Ionosphere - Karl Rawer's legacy". Adv. Radio Sci. 2, 283, 2004
External links
International Reference Ionosphere
1913 births
2018 deaths
German men centenarians
20th-century German physicists
Radio frequency propagation
Officers Crosses of the Order of Merit of the Federal Republic of Germany
Luftwaffe personnel of World War II
People from Neunkirchen, Saarland | Karl Rawer | Physics | 688 |
11,128,235 | https://en.wikipedia.org/wiki/Phomopsis%20prunorum | Phomopsis prunorum is a plant pathogen infecting apples.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Apple tree diseases
prunorum
Fungus species | Phomopsis prunorum | Biology | 39 |
27,370,978 | https://en.wikipedia.org/wiki/Singleton%20%28global%20governance%29 | In futurology, a singleton is a hypothetical world order in which there is a single decision-making agency at the highest level, capable of exerting effective control over its domain, and permanently preventing both internal and external threats to its supremacy. The term was first defined by Nick Bostrom.
Overview
According to Nick Bostrom, a singleton is an abstract concept that could be implemented in various ways:
Bostrom argues that a superintelligence could form a singleton. Technologies for surveillance and mind control could also facilitate the creation of a singleton.
A singleton has both potential risks and potential benefits. Notably, a suitable singleton could solve world coordination problems that would not otherwise be solvable, opening up otherwise unavailable developmental trajectories for civilization. For example, Ben Goertzel, an AGI researcher, suggests humans may instead decide to create an "AI Nanny" with "mildly superhuman intelligence and surveillance powers", to protect the human race from existential risks like nanotechnology and to delay the development of other (unfriendly) artificial intelligences until and unless the safety issues are solved. A singleton could set "very strict limitations on its own exercise of power (e.g. punctiliously confining itself to ensuring that certain treaty-specified international rules—or libertarian principles—are respected)". Furthermore, Bostrom suggests that a singleton could hold Darwinian evolutionary pressures in check, preventing agents interested only in reproduction from coming to dominate.
Yet Bostrom also regards the possibility of a stable, repressive, totalitarian global regime as a serious existential risk. The very stability of a singleton makes the installation of a bad singleton especially catastrophic, since the consequences can never be undone. Bryan Caplan writes that "perhaps an eternity of totalitarianism would be worse than extinction".
Similarly Hans Morgenthau stressed that the mechanical development of weapons, transportation, and communication makes "the conquest of the world technically possible, and they make it technically possible to keep the world in that conquered state". Its lack was the reason why great ancient empires, though vast, failed to complete universal conquest of their world and perpetuate the conquest. Now, however, this is possible. Technology undoes both geographic and climatic barriers. "Today no technological obstacle stands in the way of a world-wide empire", as "modern technology makes it possible to extend the control of mind and action to every corner of the globe regardless of geography and season."
See also
AI takeover
Existential risk
Friendly artificial intelligence
Superintelligence
Superpower
References
Singularitarianism
Globalism
International relations
Risk analysis
Supranational unions
World government
Global issues
Government by algorithm | Singleton (global governance) | Engineering | 542 |
22,034,837 | https://en.wikipedia.org/wiki/John%20M.%20Dawson | John Myrick Dawson (30 September 1930 in Champaign, Illinois – 17 November 2001 in Los Angeles) was an American computational physicist and the father of plasma-based acceleration techniques. Dawson earned his degrees in physics from the University of Maryland, College Park: a B.S. in 1952 and Ph.D. in 1957. His thesis "Distortion of Atoms and Molecules in Dense Media" was prepared under the guidance of Zaka Slawsky.
On graduation, John joined the Princeton Plasma Physics Laboratory (a.k.a. Project Matterhorn). Initially a research physicist, he rose to head the theoretical group from 1966 to 1973. He also spent two years (1969–71) at the Naval Research Laboratory in Washington, D.C., where he started a plasma simulation group. He then joined UCLA in 1973 as a professor of physics. He served as director of UCLA's Center for Plasma Physics and Fusion Engineering from 1976 to 1987. He was associate director of the Institute for Plasma and Fusion Research from 1989 to 1991, principal scientist with the institute since 1989 and the institute's interim director.
John was a leading figure in the plasma physics community for more than four decades, with his contributions to science spanning all of plasma physics. He performed seminal work on magnetic fusion, inertial confinement fusion, space plasmas, plasma astrophysics, free-electron lasers, and basic plasma physics. He also proposed numerous controlled-fusion concepts. A visionary, he realized as early as the late 1950s the potential impact of simulations as a way to test both theories and large construction projects before they were built. He used simulations in 1959 to answer such fundamental questions as how large can a plasma wave become before breaking. During the late 1970s and 1980s, John was using simulations to test out new ideas such as plasma-based acceleration. By the 1990s, he was realizing his broader vision for simulations in such projects as the Numerical Tokamak.
In the late 1970s and 1980s, while at UCLA, John pioneered the field of plasma-based acceleration. He proposed letting particles surf on the plasma-wave wakes left behind by a laser or a particle beam as it moved through plasma. The fields in these wakes can be more than 1000 times higher than in conventional accelerators.
A true humanitarian, Dawson believed that science was still the most noble of professions. He believed strongly in the importance of controlled nuclear-fusion research and was particularly proud of his invention of an isotope separation process that was used to detect cancer and, consequently, help save many lives. John had successfully overcome life-threatening illnesses several times. Shortly before his death, he had been in improving health and had enjoyed attending APS's division of plasma physics meeting in Long Beach, California.
Honours and awards
Dawson received the James Clerk Maxwell Prize for Plasma Physics in 1977 and the Aneesur Rahman Prize for Computational Physics in 1994; both are the highest honors bestowed by the American Physical Society's plasma physics and computational physics divisions, respectively. He was named California Scientist of the Year by the California Science Center in 1978. The Rahman prize is the highest honor given by the American Physical Society for work in computational physics. He was a member of the National Academy of Sciences, and a recipient of the California Scientist of the Year award, a Fulbright Fellowship, and two UCLA physics teaching awards.
James Clerk Maxwell Prize for Plasma Physics (1977) citation "For his outstanding contributions to plasma physics and controlled fusion as both as innovative theorist and a prolific inventor, whose ideas have provided the basis for several current fusion configurations. He initiated the use of computer simulation as a new and powerful tool for the study of plasmas. He inspired and trained a cadre of younger theorists to continue the development of the field he initiated."
Aneesur Rahman Prize (1994) citation "In recognition of his leading role in opening the field of computer simulation of plasmas and for numerous major contributions made using plasma simulation as a complement to analytic theory and experiment. He has led in opening the field of plasma-based accelerators and made major advances in understanding basic nonlinear plasma wave processes, anomalous absorption and transport, advanced plasma-based coherent light sources and space plasma phenomena."
In 2007, the American Physical Society renamed its Award for Excellence in Plasma Physics in honor of John Dawson.
Notes
References
C. Joshi, "Plasma Accelerators," Scientific American (February 2006), 294, 40-47
External links
JOHN M. DAWSON, PhD Virtual Memorial Garden
20th-century American physicists
Accelerator physicists
1930 births
2001 deaths
Computational physicists
University of Maryland, College Park alumni
Members of the United States National Academy of Sciences
Princeton University staff
Fellows of the American Physical Society | John M. Dawson | Physics | 942 |
15,599,815 | https://en.wikipedia.org/wiki/ASME%20BPE | ASME BPE (American Society of Mechanical Engineers: Bioprocessing Equipment) is an international Standard developed as an aid for the design and construction of equipment intended for use in the manufacturing of biopharmaceuticals. The standard is approved as an American National Standard by the ASME Board of Pressure Technologies. The first edition of this Standard was approved as an American National Standard on May 20, 1997. The most recent edition was approved by ANSI on March 21, 2022.
New editions of the standard are generally approved and published every two years.
Purpose and Scope
The ASME Bioprocessing Equipment (BPE) Standard was developed to aid in the design and construction of new fluid processing equipment used in the manufacture of biopharmaceuticals, where a defined level of purity and bioburden control is required. The Standard typically applies to (a) components that are in contact with the product, raw materials, or product intermediates during manufacturing, development, or scale-up (b) systems that are a critical part of product manufacture [e.g., water-for-injection (WFI), clean steam, filtration, and intermediate product storage]. Within scope also is the design and construction of piping systems for hygienic service.
Multi-Use metallic, Multi-Use plastic and Single-Use materials of construction and design, are all covered in the scope of the 2022 edition.
New editions of the ASME BPE Standard may be used beginning with the date of issuance and become effective 6 months after the date of issuance.
The ASME BPE Standard provides requirements for systems and components that are subject to cleaning and sanitization and/or sterilization including systems that are cleaned in place (CIP’d) and/or steamed in place (SIP’d) and/or other suitable processes used in the manufacturing of biopharmaceuticals. It also provides requirements for single-use systems and components used in the above listed applications. This Standard may be used, in whole or in part, for other applications where bioburden risk is a concern. This Standard applies to:
(a) new system (and component) design and fabrication
(b) definition of system boundaries
(c) specific metallic, polymeric, and elastomeric (e.g., seals and gaskets) materials of construction
(d) component dimensions and tolerances
(e) surface finishes
(f) materials joining
(g) examinations, inspections, and testing
(h) certification
This Standard is intended to apply to new fabrication and construction. It may be used in other cases with consensus between the system owner/user, engineer, installation contractor, and inspection contractor.
Please note: This paraphrased information comes from Part GR-1 and GR-2 of the ASME BPE Standard, 2022 edition, and was condensed for brevity to a broader audience. The intent of this article is general knowledge and general information for a wider audience outside of bioprocessing and engineering. Please purchase a copy of the most recent edition for complete understanding, reference, detail, context and content.
Structure
The ASME BPE is a voluntary consensus standard written by a team of over three hundred balanced subject matter experts. These individuals provide their knowledge and experience to drive technology and innovation forward safely and responsibly for the manufacturing of modern biopharmaceuticals. ASME controls the development and approval of all content by rigorous policies and procedures, ensuring that a thorough vetting process occurs and that the information published is reliable and trustworthy.
The Standard (2022 Edition) is split into the following Chapters and Parts. The teams that develop each Part function as working teams, to develop, approve and refine content.
Chapter 1, Introduction, Scope, and General Requirements
Part GR, General Requirements
Chapter 2, Certification
Part CR, Certification Requirements
Chapter 3, Materials
Part MM, Metallic Materials
Part PM, Polymeric and Other Nonmetallic Materials
Chapter 4, Design for Multiuse
Part SD, Systems Design for Multiuse
Chapter 5, Process Components for Multiuse
Part DT, Dimensions and Tolerances for Process Components
Part PI, Process Instrumentation for Multiuse
Part MC, Components for Multiuse
Chapter 6, Fabrication, Assembly, and Erection for Multiuse
Part MJ, Materials Joining for Multiuse
Part SF, Process Contact Surface Finishes for Multiuse
Chapter 7, Design for Single-Use
Part SU, Systems Design for Single-Use
Chapter 8, Process Components for Single-Use
Part SC, Components for Single-Use
Chapter 9, Fabrication, Assembly, and Erection for Single-Use
Part SJ, Joining Methods for Single-Use
How to get involved
The ASME BPE meets three times a year in person, but offline meetings occur to develop and refine existing content. Unless otherwise stated, the sessions are free and open to all, and volunteers are welcome. ASME posts the details for all meetings on their website; the link is also below.
False claims of codification
At least as early as April 19, 2011, ASME published a web page which falsely indicated the ASME BPE standard had been adopted by the State of California. The statement was based upon California's codification of Section 443, Group L—known as the "L Occupancy"—within Part 1 of the California Building Code. The web page claimed that the "L Occupancy" referenced the ASME BPE standard, but no such reference appears as described. A codification of the ASME BPE standard via such a reference is generally precluded by the building code's own requirement that any content that is not a building standard as defined in California's Health and Safety Code Section 18909 shall not be construed as part of the provisions of the California Building Code (Part 1, Chapter 1, Section 1.1.6).
The web page has been removed.
See also
ISO 2852
Single use systems
References
Huitt, Bill. (2016). Bioprocessing Piping and Equipment Design: A Companion Guide for the ASME BPE Standard (Wiley-ASME Press Series) 1st Edition. Wiley-ASME Press Series. https://www.amazon.com/Bioprocessing-Piping-Equipment-Design-Wiley-ASME/dp/1119284236
External links
Bioprocessing Equipment Certification. ASME Certification Program application and details for stainless steel tubing and fittings
ASME BPE, 2022 (Current) Edition. ASME BPE Codes & Standards, BPE-2022
ASME Calendar of Events. ASME Searchable Calendar of Events
ASME Bioprocessing Equipment Standards Committee
Biology organizations
ASME | ASME BPE | Engineering | 1,382 |
20,625,996 | https://en.wikipedia.org/wiki/External%20floating%20roof%20tank | An external floating roof tank is a storage tank commonly used to store large quantities of petroleum products such as crude oil or condensate. It consists of an open- topped cylindrical steel shell equipped with a roof that floats on the surface of the stored liquid. The roof rises and falls with the liquid level in the tank. As opposed to a fixed roof tank there is no vapor space (ullage) in the floating roof tank (except for very low liquid level situations). In principle, this eliminates tank breathing loss and greatly reduces the evaporative loss of the stored liquid. There is a rim seal system between the tank shell and roof to reduce rim evaporation.
The roof has support legs hanging down into the liquid. At low liquid levels the roof eventually lands and a vapor space forms between the liquid surface and the roof, similar to a fixed roof tank. The support legs are usually retractable to increase the working volume of the tank.
Advantages
External roof tanks are usually installed for environmental or economical reasons to limit product loss and reduce the likelihood of emission of volatile organic compounds (VOCs) and other potential air pollutants.
Normally, the roof of the tank rests directly on the surface of the stored liquid, leaving little vapor space and consequently leading to a much lower risk of rim space fire.
Disadvantages
Snow and rain water can accumulate on the roof. Roofs are exposed to sunlight and weather which can accelerate corrosion.
System function
Water on the roof is usually drained by a special flexible hose or other special drain line system that runs from drain-sumps on the roof, through the stored liquid to a drain valve on the shell at the base of the tank. A hose is the shortest quickest route, Other drain systems are available both rigid and semi-rigid. These are named 'Articulated' as they use straight lengths of steel pipes with mechanical swivel joints or consist of steel pipes with flexible sections.
See also
Storage tank
Fixed roof tank
References
External links
Use of floating roof storage tanks in Oil & Gas industry
Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area Sources. Chapter 7. Chapter 7: Liquid Storage Tanks
Oil storage
Petroleum production
Storage tanks | External floating roof tank | Chemistry,Engineering | 443 |
8,477,058 | https://en.wikipedia.org/wiki/Multi-master%20bus | A multi-master bus is a computer bus in which there are multiple bus master nodes present on the bus.
This is used when multiple nodes on the bus must initiate transfer.
For example, direct memory access (DMA) is used to transfer data between peripherals and memory without the need to use the central processing unit (CPU).
Some buses like I²C use multi-mastering inherently to allow any node to initiate a transfer with another node.
Computer buses
References | Multi-master bus | Technology | 96 |
18,687,566 | https://en.wikipedia.org/wiki/List%20of%20Nepenthes%20species | This list of Nepenthes species is a comprehensive listing of all known species of the carnivorous plant genus Nepenthes. It includes 179 recognised extant species, 2 incompletely diagnosed taxa, and 3 nothospecies. Three possible extinct species are also covered.
The official IUCN conservation status of each species is taken from the latest edition of the IUCN Red List. Unofficial assessments based on the IUCN criteria are also included, but are presented in italics. Unless otherwise noted, taxonomic determinations and all other information are sourced from Stewart McPherson's two-volume Pitcher Plants of the Old World, published in 2009. Where recent literature provides an altitudinal distribution that falls outside the range given in Pitcher Plants of the Old World, the discrepancy is noted.
All major islands within a species's geographic range are included. Smaller surrounding islands are listed separately under "Minor islands", though these lists are not exhaustive. In the case of archipelagos such as the Philippines, the individual islands to which the species is native are shown in brackets.
Authorities are presented in the form of a standard author citation, using abbreviations specified by the International Plant Names Index. Years given denote the year of the species's formal publication under the current name, thus excluding the earlier basionym date of publication if one exists.
Extant species
Incompletely diagnosed taxa
The following undescribed taxa are taken from Pitcher Plants of the Old World and its supplementary volume, New Nepenthes, published in 2011.
Nothospecies
Matthew Jebb and Martin Cheek recognised the following three nothospecies in their monographs on the genus ("A skeletal revision of Nepenthes (Nepenthaceae)" (1997) and "Nepenthaceae" (2001)). In the recent literature, these taxa have generally been treated as natural hybrids rather than as species. Of the three, N. × kinabaluensis has the strongest claim to species status, as it grows in two large, self-sustaining populations independent of its putative parent species. These populations are reportedly true breeding. Jumaat Haji Adam and C. C. Wilcock advocated the recognition of N. × kinabaluensis as a species in a 1998 article.
Extinct species
Fossil pollen of various provenance, much of it originally described under the form taxon Droseridites, has been tentatively assigned to Nepenthes by several authors. The following three species were transferred to the genus Nepenthes by Wilfried Krutzsch in 1985.
Some authors consider Droseridites major and D. parvus as synonyms of Nepenthidites laitryngewensis.
Pollen from the Kerguelen Islands originally described as D. spinosus has also been interpreted as belonging to Nepenthes.
See also
List of Nepenthes species by distribution
List of Nepenthes natural hybrids
Notes
References
02
Nepenthes02
Nepenthes02
Nepenthes Species List02 | List of Nepenthes species | Biology | 606 |
53,839,121 | https://en.wikipedia.org/wiki/Endless%20runway | An endless runway is an aircraft runway which loops around to form a shape such as a circle. There were experiments with this concept in the 1960s and it is now being researched at the Nederlands Lucht- en Ruimtevaartcentrumthe national aerospace laboratory of the Netherlands.
History
With the birth of aviation, the thought of taking a car to the office became old-style and soon people started to invent ways to take the airplane to the office. In an article in "Popular Science" from 1919, a circular runway was designed on top of some skyscrapers in New York, where one of the buildings would serve the purpose of aircraft parking. A design was made for a circular runway on the roof of Kings Cross railway station in London.
In the 1960s, the idea was taken up by a marine officer, who actually performed a number of take-offs and landings with aircraft at a circular track designed for testing cars. This work stimulated a large number of patents with runways shaped as circles or ovals and often straight tracks attached to it for taking off and landing.
In the 2010s, the idea was studied by a European consortium led by an engineer at the Royal Netherlands Aerospace Centre. Their plans for a pilot included a smaller circular runway for delivery drones.
Safety issues
Increased runway width. Instrument Landing System can be used for the straight approach but will require modification or a new system to cope with the curving runway. Water will run off the banked runway better than at present. Use of residual heat from parking lots and offices could be used to heat the runway to reduce ice.
See also
Index of aviation articles
Rocket sled launch
Ski-jump (aviation)
References
External links
Video link of proposed runway
Airport engineering | Endless runway | Engineering | 346 |
63,046,013 | https://en.wikipedia.org/wiki/Nathalie%20Wahl | Nathalie Wahl (born 1976) is a Belgian mathematician specializing in topology, including algebraic topology, homotopy theory, and geometric topology. She is a professor of mathematics at the University of Copenhagen, where she directs the Copenhagen Center for Geometry and Topology.
Education and career
Wahl was born in Brussels, and earned a license in mathematics in 1998 at the Université libre de Bruxelles, advised by Jean-Paul Doignon. Her undergraduate thesis concerned infinite antimatroids, and she published the same material in 2001 as her first journal paper. She completed a Ph.D. at the University of Oxford in 2001, with a dissertation Ribbon Graphs and Related Operads in algebraic topology supervised by Ulrike Tillmann.
After short-term positions at Northwestern University, Aarhus University, and the University of Chicago, she joined the Department of Mathematical Sciences at the University of Copenhagen in 2006, and was promoted to full professor there in 2010. In 2020 she became Center Leader of the Copenhagen Center for Geometry and Topology.
Recognition
In 2008, Wahl won the Young Elite Researcher Award (Ung Eliteforskerprisen) of the Independent Research Fund Denmark (Danmarks Frie Forskningsfond).
In 2016, she was elected to the Danish Academy of Natural Sciences.
References
External links
Home page
1976 births
Living people
Belgian mathematicians
Belgian women mathematicians
Topologists
Université libre de Bruxelles alumni
Alumni of the University of Oxford
Academic staff of the University of Copenhagen | Nathalie Wahl | Mathematics | 296 |
14,020,571 | https://en.wikipedia.org/wiki/Chartered%20architect | A chartered architect in the United Kingdom is a corporate member of one or more of the following architects' professional bodies:
the Royal Institute of British Architects
the Royal Society of Ulster Architects
the Royal Incorporation of Architects in Scotland
To become a corporate member, an architect must have passed, or gained exemption from, RIBA parts I, II and III, which includes at least two years working in practice (a minimum of seven years in total) before being able to apply.
References
External links
Royal Institute of British Architects
Royal Society of Ulster Architects
Royal Incorporation of Architects in Scotland
Registration of architects in the United Kingdom
Architecture occupations | Chartered architect | Engineering | 122 |
31,758,785 | https://en.wikipedia.org/wiki/Turacoverdin | Turacoverdin is a unique copper uroporphyrin pigment responsible for the bright green coloration of several birds of the family Musophagidae, most notably the turaco. It is chemically related to turacin, a red pigment also found almost exclusively in turacos. Turacoverdin is one of the only true green pigments found in birds, as the coloration that appears in most green feathers is due to the unique properties of blue structural coloration in combination with yellow carotenoids. Turacoverdin and turacin were the first ever chemically characterized feather pigments, and turacoverdin was first isolated and described in 1882 by Dr. C.F.W. Krukenberg.
Chemical properties
Few studies into the chemical nature of turacoverdin have been performed to date. Research by R.E. Moreau in the 1950s showed it to be less soluble in basic solutions than its chemical cousin turacin. While originally thought to contain little copper by its discoverer, who instead believed it to be iron-based, later spectroscopic analysis demonstrated high copper (and low iron) content in pigment from the green feathers of the Knysna turaco and the Schalow's turaco. Moreau also demonstrated that the green coloration of turacos might actually be due to the combined effect of two different turacoverdin pigments that differ slightly in polarity.
When extracted and exposed to light, oxygen, or strong bases, turacin has been shown to take on a green hue. This has caused several researchers to suggest that turacoverdin may be an oxidized metabolite of turacin. This has been supported by data comparing the absorption bands of the "altered turacin" with those of turacoverdin, which are shown to be very similar to one another. Several researchers have noted the chemical similarities between turacin and turacoverdin. This relationship has been supported by spectral properties, the fact that both pigments contain copper, their similar microscopic arrangement in feather cells, and the co-occurrence of the pigments: turacin and turacoverdin are always found together in the same species, and in many cases are also found in the same plumage locations. The green appearance of turacoverdin can be derived from its absorbance curve, which peaks at blue wavelengths and in the long-wave range above yellow. Turacoverdin shows little UV reflectance.
Phylogenetic evidence
Turacin and turacoverdin are both found in four of the six genera of turacos. The subfamily Criniferinae is typically regarded as being devoid of the brighter pigments, although the genus Corythaeola does have a small stripe of turacoverdin on its breast. The remaining turaco genera are placed in the subfamily Musophaginae and are referred to as the turacin-bearing turacos. More than half of turaco species belong to the genus Tauraco, and are all notable for being mostly a vivid green.
Recent spectrophotometric evidence suggests that turacoverdin may be closely related or identical to green pigments in the feathers of the northern jacana (Jacana spinosa), the blood pheasant (Ithaginis cruentus), and the crested wood-partridge (Rollulus rouloul). As Ithaginis and Rollulus are members of the order Galliformes, this has led some researchers to assume support for a turacoverdin-bearing common ancestor of Musophagidae and Galliformes, making the presence of the pigment a symplesiomorphy for these groups. The pigment data specifically suggests that turacos evolved from a group of galliform species, which is represented by the extant genera Ithaginis and Rollolus. Based on the appearance of its green feathers, researcher Jan Dyck speculates that Rollolus is closer to a possible ancestor than Ithaginis.
The northern jacana, on the other hand, is a member of the order Charadriiformes, a group clearly not closely related to either Musophagidae or Galliformes. This makes it highly unlikely that turacoverdin in Jacana reflects common ancestry with either turacos or galliforms. If the green pigment in Jacana is truly turacoverdin, then the pigment must have evolved independently in this order. This is further supported by the fact that the pigment in Jacana is located only in the remiges, while in all musophagid and galliform species, the pigment is found mainly in body feathers.
Biological significance
Turacin and turacoverdin, being copper-based pigments, require large quantities of copper in order to be manufactured. As turacos are primarily arboreal species, they are able to accumulate copper through a diet rich in fruits, flowers, buds, and other plant matter. Church and Moreau estimated that 3 months' worth of fruit intake contribute to producing the pigment present in the newly grown plumage of the turaco species T. corythaix (the Knysna turaco). It has also been observed that it takes young turacos around a year to acquire their colorful adult plumage, and some authors have speculated that they probably need that long to acquire the necessary copper. It has also been noted that turacos all live across Central Africa, which corresponds geographically with one of the world's richest copperbelts. It is unknown whether turaco diets are especially rich in copper as compared to the diets of other birds, or whether turacos are especially effective at extracting copper from their foods. It is also unknown whether turaco species lacking turacin and turacoverdin-induced pigmentation have a comparatively copper-deficient diet, absorb less copper from their diet, or lack the enzymes required to synthesize the pigments.
Although no formal tests have been performed investigating the functional significance of turacoverdin coloration, speculation abounds. Moreau in 1958 observed that turaco species inhabiting forests are more likely to be green in color than species inhabiting other environments, which may offer concealment from predators. In fact, it has been observed that the greener and denser a turaco's forest habitat, the deeper green its plumage, while non-forest-dwelling turaco species tend to be devoid of the green pigment. This claim has not been studied rigorously from a biochemical or phylogenetic perspective, however, and awaits further research. Turacos may employ their unique green coloration for sexual or social advertisement, but again no spectrophotometric or biochemical studies have been conducted to test for sex differences in coloration, and to limited human perception there appears to be none.
Other authors speculate that turacos and other birds employing the use of turacoverdin may derive a physiological and biochemical benefit from synthesizing the pigment. Copper, like porphyrins, can be damaging to birds when accumulated at high concentrations. Turacos may detoxify the high levels of copper ingested in a diet rich with porphyrins, thereby advertising the protection they've granted themselves by depositing the copper-rich pigments in their feathers. It also may be of some biological significance that turacos all seem to be pigmented with turacin and turacoverdin in exactly the same regions of the wing feathers.
See also
Turacin, a red poryphrin pigment found almost exclusively in turacos
Psittacofulvin, a brightly colored pigment unique to parrots
Melanin, a class of pigments responsible for a large range of coloration in many animal groups, and includes:
Phaeomelanin, a melanin pigment responsible for many russet, brown and tan hues in feathers
Eumelanin, a melanin pigment responsible for the deep black common to flight feathers
Carotenoids, a class of pigments responsible for many of the yellow, orange and red hues found in birds, and includes:
Astaxanthin, a red carotenoid pigment
Rhodoxanthin, a purple-red carotenoid pigment
Canthaxanthin, an orange-red carotenoid pigment
Lutein, a bright yellow carotenoid pigment
Biliverdin, a blue bile pigment responsible for the bright blue eggshells of some birds
References
Biological pigments | Turacoverdin | Biology | 1,753 |
545,511 | https://en.wikipedia.org/wiki/Indo-Pacific%20languages | Indo-Pacific is a hypothetical language macrofamily proposed in 1971 by Joseph Greenberg and now believed to be spurious. It grouped together the Papuan languages of New Guinea and Melanesia with the languages of the Andaman Islands (or at least Great Andamanese) and, tentatively, the languages of Tasmania, both of which are remote from New Guinea. The valid cognates Greenberg found turned out to be reflexes of the less extensive Trans–New Guinea family. Recently the Kusunda language (and possibly other unclassificated languages), which is generally seen as a language isolate, is also included in the Indo-Pacific proposal. Greenberg did not include "Australian" in his original 1971 proposal.
Proposal
The Indo-Pacific proposal, grouping the non-Austronesian languages of New Guinea with certain languages spoken on islands to the east and west of New Guinea, was first made by Greenberg in 1971. Greenberg's supporter Merritt Ruhlen considers Indo-Pacific an extremely diverse and ancient family, far older than Austronesian, which reflects a migration from southeast Asia that began only 6,000 years ago; he notes that New Guinea was inhabited by modern humans at least 40,000 years ago, and possibly 10,000 to 15,000 years earlier than that. Luigi Luca Cavalli-Sforza sees Indo-Pacific as a very heterogenous family of 700 languages and suggests that it may be more than 40,000 years old.
Reception
Greenberg's proposal was based on rough estimation of lexical similarity and typological similarity and has not reached a stage where it can be confirmed by the standard comparative method, including the reconstruction of a protolanguage. The languages of Tasmania are extinct and so poorly attested that many historical linguists regard them as unclassifiable. Roger Blench has dismissed the Indo-Pacific proposal as improbable, observing that while it "purported to be a purely linguistic exercise...it conveniently swept up all the languages of the crinklyhaired populations in the region that were not clearly Austronesian." He writes that despite decades of further research into Papuan languages and prehistory, Indo-Pacific is still not accepted by specialists and that it "only exists in the eye of the believer." George van Driem (2001) responds as follows:
Since Greenberg's work, the languages of New Guinea have been intensively studied by Stephen Wurm. Wurm's Trans–New Guinea languages family includes about 70 percent of the languages Greenberg included in Indo-Pacific, though the internal classification is entirely different. Wurm states that the lexical similarities between Great Andamanese, West Papuan (which is not part of Trans–New Guinea), and certain languages of Timor "are quite striking and amount to virtual formal identity [...] in a number of instances", but considers this to be due to a linguistic substratum rather than a direct relationship.
Pawley (2008) is the only thorough review of the proposal. He found that all branches of Indo-Pacific except Tasmanian and Andamanese include languages from Trans–New Guinea, and that this explains the more reasonable cognates that Greenberg proposed, but because these Trans–New Guinea languages are mixed in with languages from other families in those branches, cognates linking the branches do not provide support for Greenberg's proposal that all Papuan languages are related.
Subdivision
According to Greenberg, Indo-Pacific consists of fourteen families, not counting a few which he could not classify. He suggested a tentative sub-classification into seven groups, listed in bold below. Some languages have not been identified.
Tasmanian
Great Andamanese: Southern: Chariar, Puchikwar, Kede, Kol, Juwoi; Northern: Beada, Bogijiab, Bale, Biada
Nuclear
Central
Kapauku–Baliem
Kapauku (Ekari, Ekagi), Moni, Jabi, Simori, Wolani [= TNG Paniai Lakes family]
Dem [= TNG Dem]
Uhunduni, Enggipilu [= TNG Uhunduni]
Dani (Ndani) [→ Dani]
Northern Ngalik, Oeringoep, Sawuri-Hablifuri, Southern Ngalik, Peseghem [= TNG Dani + Isirawa (probably Kwerba)]
Highland
Wurm & Laycock's Gadsup–Auyana–Awa–Tairoa + Erima, Tsinyaji [= TNG Kainantu + Madang]
Wurm & Laycock's Gende–Siane–Gahuku–Kamano–Fore [= TNG Goroka]
Wurm & Laycock's Hagen–Wahgi–Jimi–Chumbu [= Chimbu–Wahgi]
Wurm & Laycock's Enga–Huli–Pole–Wiru [= Engan + Wiru (probably Teberan–Pawaian)]
Karam (Aförö) [= Madang]
Kutubu, Fasu [= Kutubuan]
McElhanon's Huon languages + Matap, Jupna Valley, Kandomin, Wantoat [= TNG Finisterre–Huon]
Northern
Murik: Murik, Angoram (Tjimundo), Tshamberi, Kambot [= Nor–Pondo + Kambot]
Tami: Sko (Seko), Sangke, Arso, Njao, Wembi, Skofro, Ampas, Waris, Vanimo, Kilmeri, Amanab [= non-TNG Border + Skou families + unclassified Molof (Cowan's proposal)]
Arapeshan: Arapesh, Kombio, Mountain Arapesh, Torricelli, Bambita, Wam, Yambes, Kavu, Valman [= non-TNG Torricelli family]
Ndu–Kwoma: Mayo, Kwoma, Wongamusin, Iwam + Abau, Laycock's Ndu + "Tombenam", "Malu" [= non-TNG Sepik family]
Sentani: Sentani, Nafri, Tanahmerah, Nimboran, Gresik, Kemtuk, Kuangsu, Waibron Bano-Demenggong, Demta, Mekei, Boven Tor, Kwesten, Mawes, Kaure, Sause [= non-TNG Sentani + Nimboran + Tor–Kwerba + (possibly TNG) Kaure families]
Monumbo: Monumbo, Lilau, Bosngun, Nubia, Makarob, Igom, Gamai, Watam, Tanggum, Murusapa, Anaberg, Atemble, Gapun [= non-TNG Monumbo (branch of Torricelli) + Ramu & Gapun families]
Unclassified: Siaute (Olo, Torricelli); Nori (Skou); Apris (Southern Adelbert)
Southern (Kiwaiic)
Peremka, Bangu, Wandatokwe, Jiminakana, Nausaku, Kebanagara, Mani [= non-TNG Tonda family + TNG Suki]
Parb, Sanana, Dungerwab, Dorro, Dapo, Nombuio, Noraia, Potaia, Tunjuamu, Nenium (Wakamara), Karigari, Moi-e [= Kunja (Tonda family) + related Nambu + Mekwei (Nimboran family), none TNG]
Bugi, Dabu, Dibolug, Kibuli, Ngamai-iki (Tupadidi), Mbayaka (Jindabira), Agöb [= non-TNG Pahoturi family]
Jei, Toro, Ngowugar, Kanum, Moraori, Komelom (Mombum), Koneraw, Kimaghama, Riantana, Keladdar, Teri-Kawalsch, Ndom, Jab (Jelmek), Makleu [= non-TNG Morehead & Bulaka River families + TNG Mombum, Kolopom, & Morori families]
Kiwai, Ipikoi, Hibaradai, Hiwi, Urama, Iwainu, Goaribari, Kerewa, Turama, Era River, Mawata, Domori, Wabuda, Sisiame, Pirupiru, Dibiri, Karami, Eme-eme (Pepeha), Mahigi, Tureture, Tapapi (Tapari), Buniki [= TNG Inland Gulf + possibly TNG Kiwaian + non-TNG Waia]
Barika [probably Barikewa], Dugeme, Karima, Foraba, Ro (Keai, Worugi), Sesa, Tumu (Dumu, Kibiri) [= TNG Turama–Kikorian family + possibly TNG Folopa]
Kunini, Masingara, Oriomo, Jibu, Miriam, Gijara [= non-TNG Eastern Trans-Fly family]
Southwestern (Marind–Ok)
Awju: Awju Sjiagha, Awju Jenimu (Oser), Awju Pisa [= TNG Awyu–Dumut family]
Kukukuku: Kukukuku, Ashavi, Madinava [= TNG Angan]
Tirio: Tirio, Tagota, Pisirami, Arama, Anima [= TNG Tirio family]
Ok [= TNG Ok + Awin–Pa + Awyu–Dumut families]
Digul, Aran, Niinati, Metomka, Lower Muiu, Muju, Kandam, Iongom, Upper Tedi, Awin, Eastern Tedi, Western Donaldson, Upper Fly, Upper Muju, Marapka
Telefol, Unkia, "Plain Country" [= Awin]
Mandobo, Dumut, Kaeti, Wambon
Marind [= TNG Marind + perhaps non-TNG Bulaka River families]
Marind (Tugeri, incl. Gawir & Boven Mbian)
Jaqai, Sohur
Boazi, Dea, Konmak (village Y), Lake Murray, Jabga, Babwa (village Z), Gabgab, Biak (village X)
West
Western
Yava (Mantembu & Saweroe) [= non-TNG, possible isolate]
Kapaur (Iha), Baham (Patimuni), Karas [= TNG West Bomberai family]
Ajamaru, Asli-Sidi, Maibrat, Aitinjo [= non-TNG Mai Brat family]
Madik, Karon, Waipu, Moi, Seget, Kalabra, Moraid, Tehit, Waliem [= non-TNG Bird's Head family]
Meninggo (Meax), Mansibaber, Manikion, Mantion, Amberbaken, Faranjao, Mairasi, Etna Bay, Mogetemin [misidentified], Konda, Jahadian, Puragi, Kampong-Baru, Solowat, Itigo, Bira, Najarago, Tarof, Barau, Arandai, Mor[= non-TNG East Bird's Head + Amberbaken + Mairasi families + Maibrat (spurious) + TNG South Bird's Head + Mor families]
North Halmahera: Loda, Tobelo, Tabaru, Isam, Pagu, Tololiku, Wai (Waioli), Sau, Modole, Galela, Ternate, Tidore[= non-TNG North Halmahera family]
Timor–Alor: Bunak, Abui, Makasai, Oirata[= TNG Timorese languages]
Eastern
Afoa: Afoa, Tauata, Goilala, Ambo, Deba [= Goilalan family]
Kovio: Kovio, Kuepa, Oru-Lopiko, Kunimaipa, Sini, Biaru, Goiefu [= Goilalan family]
Fuyuge: Fuyuge (Mafulu), Kambesi (Tauada), Sikube (Kambana), Korona, Onunge, Agita, Vovoi, Gomali [= Goilalan family]
Koita: Biagi, Uabari, Iarumi, Karukaru, Mogoni, Agi, Isurara [typo for Isurava], Suku (Amaseba), Minjori, Kagi, Favele, Wowonga, Kokila, Eikiri, Koiari, Uberi, Koita, Iworo, Maiari, Gosisi (Tobiri), Itu, Hagari, Neneba, Barai (Managalaski), Seramina, Suambe [= Numba], Wamai, Nigubaiba, Kotoi [= Koiarian + Manubaran families]
Mailu: Mailu (Magi), Domara, Nemea, Dom (Domu), Merani, Morawa, Magori, Binahari, Monomor, Keveri, Moikoidi, Bauwaki, Kororo, Neme, Boli, Doriaidi, Buari, Okaudi, Bori, Saroa, Yabura, Avini, Lauwa, O'oku, Lauuna, Gebi, Orai-iu [= Mailuan + Manubaran + Yareban families, maybe Baruga, and crypto-Austronesian Magori & Keapara]
Elema: Elema (Haira), Kairi-Kaura, Uaripi, Toaripi (Motumotu), Milareipi, Orokolo [= Eleman family]
Dimuga: Dimuga (Nawp), Tevi, Kanamara, Gwoiden, Makiara [= Dagan family]
Binandere: Binandere, Mambare [ambiguous], Musa River, Aiga, Yoda [Yǒda/Koriri, geographically Hunjara], Berepo [presumably Binandere], Amara [presumably Binandere], Adaua [possibly Baruga], Yema-Yarawa, Mawai, Yega, Tain-Daware, Jegasa-Sarau, Jauwa (Dobodura), Hunjara, Tsia, Giumu, Tahari (incl. Aru & Duvera dialects), Maiheari, Upper Musa, Bargua, Totore [= Binanderean family + Akoye]
Mulaha: Mulaha (Iaibu), Manukolu (Lakume), Garia, Kwale [= Kwalean family]
Namau (Maipua) [an isolate, perhaps Eleman]
Northeast (Madang): Langtub, Panim, Mis, Bongu, Gorendu, Bogadjim, Sungumana (Sungum), Wuong, Wenke, Uom, Jimjam [geographically Anjam], Burumana, Koliku, Kaliko, Male, Damun, Shongu, Banara (Moando), Tombenam (also in Ndu), Dagoi, Bonaputa-Mapu, Bunubun, Ulingan, Vanembere, Bunu (Saker), Rempin (A'e), Englam, Em, Ate, Kemba, Bawaipa, Misdao, Maragum, Nupanob (Botelkude), Matepi[= Madang family]
Pacific
Bougainville
Uasi [isolate]
KKRE: Rotokas, Konua, Eivo, Keriaka [= North Bougainville family]
NNSB: Buin, NKK (Nasioi, Koianu, Koromira), STB (Telei, Siwai, Baitsi) [= South Bougainville family]
New Britain
Sulka [unclassified]
Idne [AN]
New Ireland: Letatan–Limalua, Panaras [isolate]
Baining
Taulil–Butam [= Baining family]
Central Melanesian
Central Solomons: Bilua, Baniata, Laumbe, Savo [= Central Solomons family]
Santa Cruz: Reef, Ndeni (Noole, Banua, Nea, Nabalue) [= AN]
The following were left unclassified:
[various languages suspected to be in Northern]: Senagi & Komberatoro; Busa; Urim; Kwanga (Kwanga); Yuri; Fas; Amto[= Senagi, Torricelli, Sepik, Pauwasi, Fas, Amto–Musan, and Busa families]
Arare [possibly Western] [= TNG Kayagar]
Kamoro [possibly Western]: Kajakaja, Asmat, Mimika, Asienara, Nagramandu, Sempan, Kamoro, Iria, Angandi[= TNG Asmat–Kamoro family]
Tori [possibly Western]: "South River" (Südfluss) [likely Duvle], Tori, Pauwi II, Tori Aikwakai, Sidjuai, Pauwi I, Borumessu[= Lakes Plain family + Yoke + Burmeso]
Kauwerawet: Kauwerawet, Koassa [= Kwerba family]
Gogodala [probably in Southern New Guinea]: Gogodala, Gaima, Waruna, Adiba, Girara[= TNG Gogodala family]
Tanahmerah [TNG]; Rossel Island [isolate]; Aurama–Huaruha [possibly TNG]; Mumeng I–Mumeng II [AN]; Tate [TNG Eleman]; "Williams River" [evidently Weri: Goilalan, possibly TNG]; Ondoro [TNG Koiarian]
Comparison
This classification was never widely accepted, and was largely passed over for that of Stephen Wurm. They do not agree well. For example,
Greenberg's North New Guinea family corresponds to four of Wurm's families: Sko, Sepik–Ramu, Torricelli, and the Northern branch of Trans–New Guinea;
Greenberg's West New Guinea family corresponds to four of Wurm's: East Bird's Head, Geelvink Bay, the South Bird's Head and West Bomberai branches of Trans–New Guinea, and the Bird's Head branch of West Papuan.
The few similarities are retentions from earlier linguists' work:
Greenberg's Northeast New Guinea family and Wurm's Madang–Adelbert Range branch of Trans–New Guinea reflect John Z'graggen's Madang–Adelbert Range,
Greenberg's Eastern New Guinea family and Wurm's Eastern Main-Section branch of Trans–New Guinea both preserve Tom Dutton's Southeast New Guinea family.
Notes
References
Greenberg, Joseph H. 1971. "The Indo-Pacific hypothesis." In Current Trends in Linguistics, Vol. 8: Linguistics in Oceania, edited by Thomas A. Sebeok, 808-71. The Hague: Mouton. (Reprinted in Greenberg, Genetic Linguistics, 2005, 193–275.)Family tree available at the Linguist List MultiTree Project [no longer functional as of 2014]
Greenberg, Joseph H. 2005. Genetic Linguistics: Essays on Theory and Method, edited by William Croft. Oxford: Oxford University Press.
O'Grady, Dobrovolsky, Katamba. 1997. Contemporary Linguistics.
Usher, Timothy. "A comparison of Greenberg's and Wurm's classifications." In Greenberg, Genetic Linguistics, 2005, 261–269. (Systematic tabulation of the two sets of results.)
Wurm, Stephen A. 1982. The Papuan Languages of Oceania. Tübingen: Gunter Narr.
Proposed language families
Scientific racism | Indo-Pacific languages | Biology | 4,330 |
2,064,581 | https://en.wikipedia.org/wiki/Acetone%20%28data%20page%29 | This page provides supplementary chemical data on acetone.
Material Safety Data Sheet
The handling of this chemical may incur notable safety precautions. It is highly recommended that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions.
Mallinckrodt Baker
Science Stuff
Structure and properties
Thermodynamic properties
Vapor pressure of liquid
Table data obtained from CRC Handbook of Chemistry and Physics 44th ed.
Distillation data
See also:
Carbon tetrachloride (data page)
Butanone (data page)
Spectral data
References
Chemical data pages
Chemical data pages cleanup | Acetone (data page) | Chemistry | 126 |
31,019,620 | https://en.wikipedia.org/wiki/C7H11NO4 | {{DISPLAYTITLE:C7H11NO4}}
The molecular formula C7H11NO4 (molar mass: 173.17 g/mol, exact mass: 173.0688 u) may refer to:
ACPD, or 1-Amino-1,3-dicarboxycyclopentane
Aminoshikimic acid
Oxaceprol
Molecular formulas | C7H11NO4 | Physics,Chemistry | 84 |
10,424,409 | https://en.wikipedia.org/wiki/Syn-Propanethial-S-oxide | syn-Propanethial S-oxide (or (Z)-propanethial S-oxide), a member of a class of organosulfur compounds known as thiocarbonyl S-oxides (formerly "sulfines"), is a volatile liquid that acts as a lachrymatory agent (triggers tearing and stinging on contact with the eyes).
Onion release
The chemical is released from onions, Allium cepa, as they are sliced. The release is due to the breaking open of the onion cells, which releases enzymes called alliinases. Alliinases then break down amino acid sulfoxides, generating sulfenic acids. A specific sulfenic acid, allicin or 1-propenesulfenic acid, is rapidly rearranged by another enzyme, the lachrymatory factor synthase (LFS) to give syn-propanethial S-oxide. Vapors from this volatile liquid induces tearing.
Related compounds
A structurally related lachrymatory compound, syn-butanethial S-oxide, C4H8OS, has been found in another genus Allium plant, Allium siculum.
Propanethial S-oxide forms a stable thiosultone dimer, trans-3,4-diethyl-1,2-dithietane 1,1-dioxide.
References
Organosulfur compounds
Lachrymatory agents
Pungent flavors
Onions
Sulfoxides | Syn-Propanethial-S-oxide | Chemistry | 306 |
39,082,913 | https://en.wikipedia.org/wiki/Regulatory%20Toxicology%20and%20Pharmacology | Regulatory Toxicology and Pharmacology is a monthly peer-reviewed scientific journal which covers legal aspects of toxicological and pharmacological regulations. It is published by Elsevier on behalf of the International Society of Regulatory Toxicology & Pharmacology. The current co-editors-in-chief are Lesa L. Aylward and Martin van den Berg.
Conflicts of interest
In 2002, a group of 45 academics wrote a letter accusing the journal of a concealed pro-industry bias, a possible lack of full and independent peer review, and a failure to disclose conflicts of interest, citing a case in which Gio Batta Gori, then-current editor-in-chief, was paid $30,000 by the Tobacco Institute to write an article later published in the journal dismissing the health risks of secondhand smoke. The letter's coordinator later commented that the journal "reads like an industry trade publication, but it's masked as a peer-reviewed journal" and that it lacked any "credible peer-review process." In response, the journal's publisher implemented a conflict of interest disclosure policy at the journal in January 2003, shortly before the correspondence was published.
Abstracting and indexing
The journal is abstracted and indexed in EMBASE, EMBiology, and Scopus.
According to the Journal Citation Reports, the journal has a 2014 impact factor of 2.031, ranking it 56th out of 87 journals in the category "Toxicology" and 146th out of 254 journals in the category "Pharmacology & pharmacy".
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Academic journals established in 1981
Academic journals associated with international learned and professional societies | Regulatory Toxicology and Pharmacology | Environmental_science | 353 |
3,277,097 | https://en.wikipedia.org/wiki/Phosphotungstic%20acid | Phosphotungstic acid (PTA) or tungstophosphoric acid (TPA), is a heteropoly acid with the chemical formula . It forms hydrates . It is normally isolated as the n = 24 hydrate but can be desiccated to the hexahydrate (n = 6). EPTA is the name of ethanolic phosphotungstic acid, its alcohol solution used in biology. It has the appearance of small, colorless-grayish or slightly yellow-green crystals, with melting point 89 °C (24 hydrate). It is odorless and soluble in water (200 g/100 ml). It is not especially toxic, but is a mild acidic irritant. The compound is known by a variety of names and acronyms (see 'other names' section of infobox).
In these names the "12" or "dodeca" reflects the fact that the anion contains 12 tungsten atoms. Some early workers who did not know the structure called it phospho-24-tungstic acid, formulating it as 3H2O·P2O5 24WO3·59H2O, , which correctly identifies the atomic ratios of P, W and O. This formula was still quoted in papers as late as 1970.
Phosphotungstic acid is used in histology as a component for staining of cell specimens, often together with haematoxylin as PTAH. It binds to fibrin, collagen, and fibres of connective tissues, and replaces the anions of dyes from these materials, selectively decoloring them.
Phosphotungstic acid is electron dense, opaque for electrons. It is a common negative stain for viruses, nerves, polysaccharides, and other biological tissue materials for imaging by a transmission electron microscope.
Structure
Gouzerh summarises the historical views on the structure of phosphotungstic acid leading up to Keggin's determination of the structure as:
proposed by Miolati and further developed by Rosenheim
(Pauling)
The structure was determined by J.F Keggin first published in 1933 and then in 1934 and is generally known as the Keggin structure. The anion has full tetrahedral symmetry and comprises a cage of twelve tungsten atoms linked by oxygen atoms with the phosphorus atom at its centre. The picture on the right shows the octahedral coordination of oxygen atoms around the tungsten atoms, and that the surface of the anion has both bridging and terminal oxygen atoms. Further investigation showed that the compound was a hexahydrate not a pentahydrate as Keggin had proposed.
Preparation and chemical properties
Phosphotungstic acid can be prepared by the reaction of sodium tungstate dihydrate, , with phosphoric acid, , acidified with hydrochloric acid, HCl. This procedure has been updated.
Phosphotungstic acid solutions decompose as the pH is increased. A step-wise decomposition has been determined and the approximate compositions at various pH values are as follows:
{|class="wikitable"
|-
! pH !! principal components
|-
| 1.0 ||
|-
| 2.2 ||, ,
|-
| 3.5 ||, , , ,
|-
| 5.4 ||, ,
|-
| 7.3 ||
|-
| 8.3 ||,
|}
The species is a lacunary, or defective Keggin ion. The has a Dawson structure. At pH less than 8, the presence of ethanol or acetone stabilises the anion, , reducing decomposition.
Tungstophosphoric acid is thermally stable up to 400 °C, and is more stable than the analogous silicotungstic acid, .
Large quantities of polar molecules such as pyridine are absorbed into the bulk phase and not simply adsorbed onto the surface. Solid state NMR studies of ethanol absorbed in the bulk phase show that both protonated dimers, , and monomers, , are present.
Phosphotungstic acid is less sensitive to reduction than phosphomolybdic acid. Reduction with uric acid or iron(II) sulfate produces a brown coloured compound. the related silicotungstic acid when reduced forms a similar brown compound where one of the four units in the Keggin structure becomes a metal-metal bonded cluster of three edge shared octahedra.
Phosphotungstic acid is the strongest of heteropolyacids. Its conjugate base is the anion. Its acidity in acetic acid has been investigated and shows that the three protons dissociate independently rather than sequentially, and the acid sites are of the same strength. One estimate of the acidity is that the solid has an acidity stronger than H0 = −13.16, which would qualify the compound as a superacid. This acidic strength means that even at low pH the acid is fully dissociated.
Uses
Catalyst
In common with the other heteropolyacids phosphotungstic acid is a catalyst and its high acidity and thermal stability make it a catalyst of choice according to some researchers. It is in solution as a homogeneous catalyst, and as a heterogeneous catalyst "supported" on a substrate e.g. alumina, silica. Some acid catalysed reactions include:
the homogeneous catalysis of the hydrolysis of propene to give 2-propanol
the homogeneous catalysis of the Prins reaction
the heterogeneous catalysis of the dehydration of 2-propanol to propene and methanol to hydrocarbons.
Dyeing and pigments
Phosphotungstic acid has been used to precipitate different types of dyes as "lakes". Examples are basic dyes and triphenylmethane dyes, e.g. pararosaniline derivatives.
Histology
Phosphotungstic acid is used in histology for staining specimens, as a component of phosphotungstic acid haematoxylin, PTAH, and “trichrome” reagents, and as a negative stain for imaging by a transmission electron microscope.
Phosphotungstic acid haematoxylin (PTAH)
Mallory described the reagent now generally known as PTAH in 1897. PTAH stains tissues either reddish brown or blue depending on their type. This property of simultaneously staining two different colours is different from other haematoxylin reagents e.g. alum-haematoxylin. The role of phosphotungstic acid and the mechanism of staining is not fully understood. The active component of haematoxylin is the oxidised form, haematin, although this rarely acknowledged in the literature which refer to haematoxylin staining. Phosphotungstic acid forms a lake with haematin. The make –up of the reagent is uncertain, examination of a year old sample showed there to be three coloured components, blue, red and yellow. These were not identified. Some investigations of “model” systems, reacting various compounds such as amino acids, purines, pyrimidines and amines with PTAH show that they give rise to different colours.
Trichrome reagents
In these reagents two or three basic dyes are used with phosphotungstic acid, in either a one step or multi-stage procedure. These reagents colour different tissue types different colours. Again the mechanism of staining is not fully understood. Some explanations include the proposal that phosphotungstic acid acts as a mordant to bind the dye to the tissue or that alternatively it binds to tissue blocking it to dye molecules.
Negative staining
Adsorption onto tissue or the surface of viruses and its electron density are the bases of phosphotungstic acids action as a negative stain. This electron density arises from the presence of the 12 tungsten atoms which each have an atomic number of 74. The mechanism of the adsorption onto tissue has been proposed as being electrostatic rather than involving hydrogen bonding, as adsorption is not affected by pH.
Analysis
The potassium salt is only slightly soluble, unlike most other phosphotungstate salts, and has been proposed as a method for the gravimetric analysis of potassium.
Precipitation of proteins
In a number of analytical procedures one of the roles of phosphotungstic acid is to precipitate out proteins. It has been termed a "universal" precipitant for polar proteins. Further studies showed that no precipitation occurred with α-amino groups but did occur with guanidino, ε-amino and imidazole groups.
Medicinal
Very little work appears to have been carried out in this area. One example relates to liver necrosis in rats.
Composite proton exchange membranes
The heteropoly acids, including phosphotungstic acid, are being investigated as materials in composite proton exchange membranes, such as Nafion. The interest lies in the potential of these composite materials in the manufacture of fuel cells as they have improved operating characteristics.
See also
Phosphomolybdic acid
References
Tungstic acids
Phosphates
Oxides
Staining
Electron microscopy stains
Coordination complexes
Heteropoly acids | Phosphotungstic acid | Chemistry,Biology | 1,972 |
3,209,677 | https://en.wikipedia.org/wiki/Outline%20of%20biochemistry | The following outline is provided as an overview of and topical guide to biochemistry:
Biochemistry – study of chemical processes in living organisms, including living matter. Biochemistry governs all living organisms and living processes.
Applications of biochemistry
Testing
Ames test – salmonella bacteria is exposed to a chemical under question (a food additive, for example), and changes in the way the bacteria grows are measured. This test is useful for screening chemicals to see if they mutate the structure of DNA and by extension identifying their potential to cause cancer in humans.
Pregnancy test – one uses a urine sample and the other a blood sample. Both detect the presence of the hormone human chorionic gonadotropin (hCG). This hormone is produced by the placenta shortly after implantation of the embryo into the uterine walls and accumulates.
Breast cancer screening – identification of risk by testing for mutations in two genes—Breast Cancer-1 gene (BRCA1) and the Breast Cancer-2 gene (BRCA2)—allow a woman to schedule increased screening tests at a more frequent rate than the general population.
Prenatal genetic testing – testing the fetus for potential genetic defects, to detect chromosomal abnormalities such as Down syndrome or birth defects such as spina bifida.
PKU test – Phenylketonuria (PKU) is a metabolic disorder in which the individual is missing an enzyme called phenylalanine hydroxylase. Absence of this enzyme allows the buildup of phenylalanine, which can lead to mental retardation.
Genetic engineering – taking a gene from one organism and placing it into another. Biochemists inserted the gene for human insulin into bacteria. The bacteria, through the process of translation, create human insulin.
Cloning – Dolly the sheep was the first mammal ever cloned from adult animal cells. The cloned sheep was, of course, genetically identical to the original adult sheep. This clone was created by taking cells from the udder of a six-year-old ewe and growing them in the lab.
Gene therapy – a modified or healthy gene is inserted into the organism to replace a disease-causing gene. Commonly a virus that has been altered to carry human DNA is used to deliver the healthy gene to the targeted cells of the patient. This process was first used successfully in 1990 on a four-year-old patient who lacked an immune system due to a rare genetic disease called severe combined immunodeficiency (SCID).
Branches of biochemistry
Main branches
Animal biochemistry
Plant biochemistry
Metabolism
Enzymology
Other branches
Biotechnology,
Bioluminescence,
Molecular chemistry,
Enzymatic chemistry,
Genetic engineering,
Pharmaceuticals,
Endocrinology,
Neurochemistry,
Hematology,
Nutrition,
Photosynthesis,
Environmental,
Toxicology
History of biochemistry
General biochemistry concepts
Major categories of bio-compounds:
Carbohydrates : sugar – disaccharide – polysaccharide – starch – glycogen
Lipids : fatty acid – fats – essential oils – oils – waxes – cholesterol
Nucleic acids : DNA – RNA – mRNA – tRNA – rRNA – codon – adenosine – cytosine – guanine – thymine – uracil
Proteins :
amino acid – glycine – arginine – lysine
peptide – primary structure – secondary structure – tertiary structure – conformation – protein folding
Chemical properties:
molecular bond – covalent bond – ionic bond – hydrogen bond – ester – ethyl
molecular charge – hydrophilic – hydrophobic – polar
pH – acid – alkaline – base
oxidation – reduction – hydrolysis
Structural compounds:
In cells: flagellin – peptidoglycan – myelin – actin – myosin
In animals: chitin – keratin – collagen – silk
In plants: cellulose – lignin – cell wall
Enzymes and enzyme activity:
enzyme kinetics – enzyme inhibition
proteolysis – ubiquitin – proteasome
kinase – dehydrogenase
Membranes : fluid mosaic model – diffusion – osmosis
phospholipids – glycolipid – glycocalyx – antigen – isoprene
ion channel – proton pump – electron transport – ion gradient – antiporter – symporter – quinone – riboflavin
Energy pathways :
pigments : chlorophyll – carotenoids – xanthophyll – cytochrome – phycobilin – bacteriorhodopsin – hemoglobin – myoglobin – absorption spectrum – action spectrum – fluorescence
Photosynthesis : light reaction – dark reaction
Fermentation : Acetyl-CoA – lactic acid
Cellular respiration : Adenosine triphosphate (ATP) – NADH – pyruvate – oxalate – citrate
Chemosynthesis
Regulation
hormones : auxin
signal transduction – growth factor – transcription factor – protein kinase – SH3 domain
Malfunctions : tumor – oncogene – tumor suppressor gene
Receptors : Integrin – transmembrane receptor – ion channel
Techniques : electrophoresis – chromatography – mass spectrometry – x-ray diffraction – Southern blot – fractionation – Gram stain – Surface Plasmon Resonance – Microscale Thermophoresis
Biochemical techniques
Molecular genetics
DNA sequencing
Polymerase chain reaction
Northern blotting
Southern blotting
Fusion proteins
DNA microarray
Bioinformatics
Flow cytometry
Protein purification
Western blotting
Chromatography
ELISA
Structural determination
X-ray crystallography
NMR
Electron microscopy
Molecular dynamics
Mass spectrometry
Isotopic labeling
Interactions between biomolecules
Coimmunoprecipitation
Electrophoretic mobility shift assay
Southwestern blotting
External links
Biochemistry, 5th ed. Full text of Berg, Tymoczko, and Stryer, courtesy of NCBI.
Biochemistry, 2nd ed. Full text of Garrett and Grisham.
Biochemistry
Biochemistry
Biochemistry topics
Biochemistry
Biochemistry terminology | Outline of biochemistry | Chemistry,Biology | 1,247 |
23,730,626 | https://en.wikipedia.org/wiki/Digestive%20rate%20model | The digestive rate model (DRM) (of foraging) is related to optimal foraging theory in that the model describes the diet selection that animals should perform in order to maximize the energy (or nutrients) available to them. It differs from the main body of Optimal Foraging Theory in stating that animals can select food in order to make optimal use of their digestive tract (maximize digestion rate) rather than the maximization of the food ingestion rate, which is the base of Optimal foraging theory.
The basic tenet of the DRM is that the intake of energy by an animal passes through two consecutive processes, food ingestion or foraging, and food digestion. Optimal foraging theory describes the diet selection if the food ingestion rate is the limiting factor. The DRM describes diet selection and foraging behavior if digestion is the rate limiting process. Food can consist of varying fractions of largely indigestible parts such as fibre in plant material, shells of molluscs or insect chitin, which can be thought of as 'rate limiting' for the digestion process or somewhat more intuitively as 'bulk' that takes up capacity that can be spent better for material with a higher digestibility.
The original description of the model positioned the DRM as an alternative to the contingency model (CM) of optimal foraging and pointed out that some of the predictions of the DRM provide a better match than did the CM with observed diet choice and behavior of e.g. herbivores. The DRM went largely unnoticed, but a recent paper by Van Gils describes how red knots Calidris canutus forage based on digestive bottlenecks and confirmed their foraging according to the DRM rather than the CM model of optimal foraging. The case is particularly interesting as a major difference in individual foraging behavior is related to a large intraspecific difference in the digestive tract of the knots.
See also
Behavioral ecology
Human behavioral ecology
Optimal foraging
References
Behavioral ecology
Eating behaviors | Digestive rate model | Biology | 404 |
160,332 | https://en.wikipedia.org/wiki/Ephemeris | In astronomy and celestial navigation, an ephemeris (; ; , ) is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position (and possibly velocity) over time. Historically, positions were given as printed tables of values, given at regular intervals of date and time. The calculation of these tables was one of the first applications of mechanical computers. Modern ephemerides are often provided in electronic form. However, printed ephemerides are still produced, as they are useful when computational devices are not available.
The astronomical position calculated from an ephemeris is often given in the spherical polar coordinate system of right ascension and declination, together with the distance from the origin if applicable. Some of the astronomical phenomena of interest to astronomers are eclipses, apparent retrograde motion/planetary stations, planetary es, sidereal time, positions for the mean and true nodes of the moon, the phases of the Moon, and the positions of minor celestial bodies such as Chiron.
Ephemerides are used in celestial navigation and astronomy. They are also used by astrologers. GPS signals include ephemeris data used to calculate the position of satellites in orbit.
History
1st millennium BC – Ephemerides in Babylonian astronomy.
2nd century AD – the Almagest and the Handy Tables of Ptolemy
8th century AD – the of Ibrāhīm al-Fazārī
9th century AD – the of Muḥammad ibn Mūsā al-Khwārizmī
11th century AD – the of Ibn Yunus
12th century AD – the Tables of Toledo – based largely on Arabic sources of Islamic astronomy – were edited by Gerard of Cremona to form the standard European ephemeris until the Alfonsine Tables.
13th century AD – the Zīj-i Īlkhānī (Ilkhanic Tables) were compiled at the Maragheh observatory in Persia.
13th century AD – the Alfonsine Tables were compiled in Spain to correct anomalies in the Tables of Toledo, remaining the standard European ephemeris until the Prutenic Tables almost 300 years later.
13th century AD - the Dresden Codex, an extant Mayan ephemeris
1408 – Chinese ephemeris table (copy in Pepysian Library, Cambridge, UK (refer book '1434'); Chinese tables believed known to Regiomontanus).
1474 – Regiomontanus publishes his day-to-day Ephemerides in Nürnberg, Germany.
1496 – the Almanach Perpetuum of Abraão ben Samuel Zacuto (one of the first books published with a movable type and printing press in Portugal)
1504 – While shipwrecked on the island of Jamaica, Christopher Columbus successfully predicted a lunar eclipse for the natives, using the ephemeris of the German astronomer Regiomontanus.
1531 – Work of Johannes Stöffler is published posthumously at Tübingen, extending the ephemeris of Regiomontanus through 1551.
1551 – the Prutenic Tables of Erasmus Reinhold were published, based on Copernicus's theories.
1554 – Johannes Stadius published Ephemerides novae et auctae, the first major ephemeris computed according to Copernicus' heliocentric model, using parameters derived from the Prutenic Tables. Although the Copernican model provided an elegant solution to the problem of computing apparent planetary positions (it avoided the need for the equant and better explained the apparent retrograde motion of planets), it still relied on the use of epicycles, leading to some inaccuracies – for example, periodic errors in the position of Mercury of up to ten degrees. One of the users of Stadius's tables is Tycho Brahe.
1627 – the Rudolphine Tables of Johannes Kepler based on elliptical planetary motion became the new standard.
1679 – La Connaissance des Temps ou calendrier et éphémérides du lever & coucher du Soleil, de la Lune & des autres planètes, first published yearly by Jean Picard and still extant.
1975 – Owen Gingerich, using modern planetary theory and digital computers, calculates the actual positions of the planets in the 16th century and graphs the errors in the planetary positions predicted by the ephemerides of Stöffler, Stadius and others. According to Gingerich, the error patterns "are as distinctive as fingerprints and reflect the characteristics of the underlying tables. That is, the error patterns for Stöffler are different from those of Stadius, but the error patterns of Stadius closely resemble those of Maestlin, Magini, Origanus, and others who followed the Copernican parameters."
Modern ephemeris
For scientific uses, a modern planetary ephemeris comprises software that generates positions of planets and often of their satellites, asteroids, or comets, at virtually any time desired by the user.
After introduction of electronic computers in the 1950s it became feasible to use numerical integration to compute ephemerides. The Jet Propulsion Laboratory Development Ephemeris is a prime example. Conventional so-called analytical ephemerides that utilize series expansions for the coordinates have also been developed, but of much increased size and accuracy as compared to the past, by making use of computers to manage the tens of thousands of terms. Ephemeride Lunaire Parisienne and VSOP are examples.
Typically, such ephemerides cover several centuries, past and future; the future ones can be covered because the field of celestial mechanics has developed several accurate theories. Nevertheless, there are secular phenomena which cannot adequately be considered by ephemerides. The greatest uncertainties in the positions of planets are caused by the perturbations of numerous asteroids, most of whose masses and orbits are poorly known, rendering their effect uncertain. Reflecting the continuing influx of new data and observations, NASA's Jet Propulsion Laboratory (JPL) has revised its published ephemerides nearly every year since 1981.
Solar System ephemerides are essential for the navigation of spacecraft and for all kinds of space observations of the planets, their natural satellites, stars, and galaxies.
Scientific ephemerides for sky observers mostly contain the positions of celestial bodies in right ascension and declination, because these coordinates are the most frequently used on star maps and telescopes. The equinox of the coordinate system must be given. It is, in nearly all cases, either the actual equinox (the equinox valid for that moment, often referred to as "of date" or "current"), or that of one of the "standard" equinoxes, typically J2000.0, B1950.0, or J1900. Star maps almost always use one of the standard equinoxes.
Scientific ephemerides often contain further useful data about the moon, planet, asteroid, or comet beyond the pure coordinates in the sky, such as elongation to the Sun, brightness, distance, velocity, apparent diameter in the sky, phase angle, times of rise, transit, and set, etc.
Ephemerides of the planet Saturn also sometimes contain the apparent inclination of its ring.
Celestial navigation serves as a backup to satellite navigation. Software is widely available to assist with this form of navigation; some of this software has a self-contained ephemeris. When software is used that does not contain an ephemeris, or if no software is used, position data for celestial objects may be obtained from the modern Nautical Almanac or Air Almanac.
An ephemeris is usually only correct for a particular location on the Earth. In many cases, the differences are too small to matter. However, for nearby asteroids or the Moon, they can be quite important.
Other modern ephemerides recently created are the EPM (Ephemerides of Planets and the Moon), from the Russian Institute for Applied Astronomy of the Russian Academy of Sciences, and the INPOP () by the French IMCCE.
See also
Almanac
American Ephemeris and Nautical Almanac
The Astronomical Almanac (new name)
Ephemera
Ephemeris time
Epoch (astronomy)
Epoch (reference date)
Fundamental ephemeris
January 0 or March 0
Keplerian elements
Nautical almanac
Osculating orbit
Ptolemy's table of chords
Two-line elements
William of Saint-Cloud
Notes
References
External links
The JPL HORIZONS online ephemeris
Introduction to the JPL ephemerides (archived 26 February 2005)
Astrology
Astronomical tables
Astrometry
Astronomy books
Calendars
Celestial navigation | Ephemeris | Physics,Astronomy | 1,778 |
52,637,932 | https://en.wikipedia.org/wiki/DNS%20Flood | DNS Flood is a type of denial-of-service attack. It is the process whereby the traffic on a network resource or machine is stopped for some time. The offender sends a great number of requests to the resource or machine so that it might become unavailable to those who might try to reach it. During a DNS flood the host that connects to the Internet is disrupted due to an overload of traffic. It can be referred to as a disruption that causes the work of the resource or machine to halt by not allowing the traffic to land on it.
This attack is mainly done by hackers to benefit from the attacked resource or machine. DDoS attacks have been perpetrated for many reasons, including blackmailing website owners and knocking out websites, including high-profile sites such as large bank websites.
Many methods can and are being adopted to prevent these types of attacks some of which include dropping malformed packages, use filters to avoid receiving packages from sources having potential to attack, timing out half open connections with greater hostility. One can also set SYN, ICMP, and UDP at lower levels to prevent such DDoS attacks from harming one's network.
References
Denial-of-service attacks | DNS Flood | Technology | 244 |
917,657 | https://en.wikipedia.org/wiki/Henry%20Taube | Henry Taube (November 30, 1915 – November 16, 2005) was a Canadian-born American chemist who was awarded the 1983 Nobel Prize in Chemistry for "his work in the mechanisms of electron-transfer reactions, especially in metal complexes." He was the second Canadian-born chemist to win the Nobel Prize, and remains the only Saskatchewanian-born Nobel laureate. Taube completed his undergraduate and master's degrees at the University of Saskatchewan, and his PhD from the University of California, Berkeley. After finishing graduate school, Taube worked at Cornell University, the University of Chicago and Stanford University.
In addition to the Nobel Prize, Taube also received many other major scientific awards, including the Priestley Medal in 1985 and two Guggenheim Fellowships early in his career (1949 and 1955), as well as numerous honorary doctorates. His research focused on redox reactions, transition metals and the use of isotopically labeled compounds to follow reactions. He had over 600 publications including one book, and had mentored over 200 students during his career. Taube and his wife Mary had three children; his son Karl is an anthropologist at the University of California Riverside.
Education
At 12, Taube left his hometown and moved to Regina to attend Luther College where he completed high school. After graduating, Taube stayed at Luther College and worked as laboratory assistant for Paul Liefeld, allowing him to take first year university classes. Taube attended the University of Saskatchewan, receiving his BSc in 1935 and his MSc in 1937. His thesis advisor at the University of Saskatchewan was John Spinks. While at the University of Saskatchewan, Taube studied with Gerhard Herzberg, who would be awarded the 1971 Nobel Prize in Chemistry. He moved to University of California, Berkeley, where he completed his PhD studies in 1940. His PhD mentor was William C. Bray. Taube's graduate research focused on the photodecomposition of chlorine dioxide and hydrogen peroxide in solution.
Research and academic career
Academic posts
After completing his education, Taube remained in the United States, becoming an instructor in chemistry at Berkeley until 1941. He initially wanted to return to Canada to work, but did not receive a response when he applied for jobs at the major Canadian universities. From Berkeley, he served as an instructor and assistant professor at Cornell University until 1946. During World War II, Taube served on the National Defense Research Committee. Taube spent time at the University of Chicago as an assistant professor, associate professor and as a full professor from 1946 to 1961. He served as chair of the chemistry department in Chicago from 1956 to 1959, but did not enjoy administrative work. After leaving Chicago, Taube worked as a professor at Stanford University until 1986, a position that allowed him to focus on research, while also teaching classes at the undergraduate and graduate levels. He became a Professor Emeritus at Stanford in 1986, but he continued to perform research until 2001, and visited his labs every day until his death in 2005. In addition to his academic duties, Taube also served as a consultant at Los Alamos National Laboratory from 1956 until the 1970s.
Research interests
Taube's initial research at Cornell University focused on the same areas he studied as a graduate student, oxidizing agents containing oxygen and halogens, and redox reactions featuring these species. He used isotopically labeled oxygen-18 and radioactive chlorine to study these reactions. He was recognized by the American Chemical Society in 1955 for his isotope studies.
Taube's interest in coordination chemistry was sparked when he was chosen to develop a course on advanced inorganic chemistry while at the University of Chicago. He was unable to find much information in the textbooks available at the time. Taube realized that his work on the substitution of carbon in organic reactions could be related to inorganic complexes. In 1952, Taube published a key paper relating the rates of chemical reactions to electronic structure in Chemical Reviews. This research was the first to recognize the correlation between the rate of ligand substitution and the d-electron configuration of the metal. Taube's key discovery was the way molecules build a type of "chemical bridge" rather than simply exchanging electrons, as previously thought. Identifying this intermediate step explained why reactions between similar metals and ions occurred at different rates. His paper in Chemical Reviews was developed while on sabbatical in the late 1940s. An article in Science called this paper "one of the true classics in inorganic chemistry" after his Nobel Prize was announced. Taube researched ruthenium and osmium, both elements have a high capacity for back bonding. This type of electron donation was key when studying the way electrons are transferred between molecules in a chemical reaction.
When looking back on his research, Taube explained that he sometimes had difficulty finding graduate students willing to work on electron transfer reactions, as they preferred to work on more "exciting" projects in his laboratory focusing on the effects of isotopic tracers and kinetics. Taube felt that a "primary flaw" with his correlation between electron configuration and ligand substitution was that it was described mainly in terms of valence bond theory, as crystal field theory and ligand field theory were not well established when he published his work in 1952.
Awards and honors
Nobel Prize
Taube was awarded the 1983 Nobel Prize in Chemistry "for his work on the mechanisms of electron transfer reactions, especially in metal complexes." He received his award on December 8, 1983, with the presentation speech being delivered by Ingvar Lindqvist of the Swedish Royal Academy of Sciences. Taube's Nobel Lecture was entitled "Electron Transfer between Metal Complexes – Retrospective." His Nobel Prize was the second awarded to a Canadian-born chemist (the first one was William Giauque). His initial paper in Chemical Reviews was 30 years old at the time of his Nobel Prize victory, but the correlation he described between the rate of ligand substitution and electronic configuration for transition metal coordination complexes was still the predominant theory about the reaction chemistry of these compounds. After being awarded the Nobel Prize, Taube noticed a side benefit to the prestigious award – his students paid better attention in class.
Other awards
Taube was accepted as a member of the National Academy of Sciences in 1959. In 1961, he was elected to the American Academy of Arts and Sciences. President Jimmy Carter presented Taube with the 1976 President's National Medal of Science "in recognition of contributions to the understanding of reactivity and reaction mechanisms in inorganic chemistry." He was elected to the American Philosophical Society in 1981. In 1985, Taube received the American Chemical Society's highest honor, the Priestley Medal, which is awarded to recognize "distinguished services to chemistry". He was awarded Guggenheim Fellowships in 1949 and 1955. In 1965, he received the Golden Plate Award of the American Academy of Achievement. Taube was made an honorary member of the College of Chemists of Catalonia and Beleares (1984), the Canadian Society of Chemists (1986), and the Hungarian Academy of Sciences (1988). He was also awarded an honorary fellowship in the Royal Society of Chemistry (1989) and the Indian Chemical Society (1989) and elected a Fellow of the Royal Society (FRS) in 1988. Taube received honorary degrees from many institutions, including the University of Saskatchewan (1973), the University of Chicago (1983), the Polytechnic Institute of New York (1984), the State University of New York Stony Brook (1985), the University of Guelph (1987), Seton Hall University (1988), the Lajos Kossuth University of Debrecen in Hungary (1988) and Northwestern University (1990). A Nobel Laureate Plaza on the University of Saskatchewan's campus in honor of Taube and Gerhard Herzberg was dedicated in 1997.
Legacy
In 1981, Taube became a founding member of the World Cultural Council. As of 1997, Taube had over 600 publications, and had worked with over 250 students. He published a book, Electron Transfer Reactions of Complex Ions in Solution (Current Chemical Concepts) in 1970. His students have had faculty positions at many prestigious universities, including Cornell, Rutgers, Georgetown and Georgia Tech. Together with graduate student Carol Creutz, he is the namesake of the Creutz-Taube complex, a metal complex with the formula [Ru(NH3)5]2(C4H4N2)5+. His research contributions have been honored in several ways, including a symposium at the 1982 annual American Chemical Society meeting. The annual series Progress in Inorganic Chemistry dedicated its 30th volume to Taube, entitled "An Appreciation of Henry Taube." Luther College in Regina, Saskatchewan offers an annual scholarship to an entering science student in honor of Taube and his science teacher, Paul Liefeld. A seminar series was created in honor of his work at Stanford. Taube gave the inaugural lecture in the series.
Colleagues remember Taube as a dedicated scientist, Jim Collman of Stanford said "Henry was a scientist's scientist and a dominant figure in the field of inorganic chemistry." Harry Gray, a professor at California Institute of Technology said, "He was in a class by himself, a role model and leader whom we all admired and loved." Former student Peter Ford remembers that Taube "made chemistry not only challenging and stimulating, but a lot of fun as well."
Personal life
Taube was born November 30, 1915, in Neudorf, Saskatchewan, as the youngest of four boys. His parents were ethnic Germans from Ukraine who had immigrated to Saskatchewan from Ukraine in 1911. Growing up, his first language was Low German. In the 18th century, Catherine the Great encouraged Central European farmers to settle in Russia. As the rights afforded to these settlers by Catherine were gradually diminished, many of the settlers headed to North America, with Saskatchewan offering good farmland, and other incentives for immigrants. Taube reflected fondly on his experiences growing up in Saskatchewan, noting: "Certainly, there is nothing about my first 21 years in Saskatchewan, taken in the context of those times that I would wish to be changed. The advantages that I enjoyed include: the marvelous experience of growing up on a farm, which taught me an appreciation of nature, and taught me also to discipline myself to get necessary jobs done..."
After completing his graduate studies, Taube became a naturalized citizen of the United States in 1942. Taube married his wife Mary in 1952. They had three children, Karl, Heinrich, and Linda. His stepdaughter Marianna died of cancer in 1998. When he stopped his active research projects in 2001, Taube continued to be available as a reviewer and consultant, but his main goal was "enjoying life". Away from chemistry, Taube had varied interests including gardening and classical music, mainly opera. In 2003 he was one of 22 Nobel laureates who signed the Humanist Manifesto.
Taube died at his home in Palo Alto, California on November 16, 2005, at the age of 89.
See also
Rudolph A. Marcus, who was awarded the 1992 Nobel Prize in Chemistry for his contribution to the RRKM theory on electron transfer
References
Publications
Taube, H., Jackson, J. A. & J. F. Lemons. "Oxygen-17 NMR Shifts Caused by Cr2+ in Aqueous Solutions", Los Alamos Scientific Laboratory, United States Department of Energy (through predecessor agency the Atomic Energy Commission), (1962).
Taube, H. "Reactions of Solvated Ions Final Report", University of Chicago, United States Department of Energy (through predecessor agency the Atomic Energy Commission), (September 24, 1962).
Taube, H. & A. Viste. "Isotopic Discrimination of Some Solutes in Liquid Ammonia", University of Chicago, Stanford University, United States Department of Energy (through predecessor agency the Atomic Energy Commission), (1966).
Taube, H. "Final Technical Report of Research", Stanford University, United States Department of Energy (through predecessor agency the Atomic Energy Commission), (April 3, 1972).
External links
1915 births
2005 deaths
Inorganic chemists
20th-century American chemists
American Nobel laureates
Canadian people of German descent
Canadian emigrants to the United States
Canadian Nobel laureates
Cornell University faculty
Nobel laureates in Chemistry
Fellows of the Royal Society of Canada
National Medal of Science laureates
Members of the Brazilian Academy of Sciences
UC Berkeley College of Chemistry alumni
University of Saskatchewan alumni
Recipients of the National Order of Scientific Merit (Brazil)
Foreign members of the Royal Society
People from Neudorf, Saskatchewan
Luther College (Saskatchewan) alumni
Members of the United States National Academy of Sciences
Founding members of the World Cultural Council
Members of the American Philosophical Society | Henry Taube | Chemistry | 2,562 |
3,474,975 | https://en.wikipedia.org/wiki/AMPAC | AMPAC is a general-purpose semiempirical quantum chemistry program. It is marketed by Semichem, Inc. and was developed originally by Michael Dewar and his group.
The first version of AMPAC (2.1) was made available in 1985 through the Quantum Chemistry Program Exchange (QCPE). Subsequent versions were released through the same source, representing minor updates and optimized versions for other platforms.
In 1992, Semichem, Inc. was formed at Professor Dewar's urging to maintain and market the program. AMPAC 4.0 with Graphical User Interface was released in August of that year. Semichem's current version of AMPAC is 10.
AMPAC current implements the SAM1, AM1, MNDO, MNDO/d, PM3, MNDOC MINDO/3, RM1 and PM6 semi-empirical methods and AMSOL and COSMO salvation models.
See also
Quantum chemistry computer programs
References
Computational chemistry software | AMPAC | Chemistry | 201 |
72,053,099 | https://en.wikipedia.org/wiki/List%20of%20alismatid%20families | The alismatid monocots are a group of 15 interrelated families of flowering plants, named for their largest order, Alismatales. Like other monocots, they usually have a single embryonic leaf (cotyledon) in their seeds, scattered vascular systems, leaves with parallel veins, flowers with parts in threes or multiples of three, and roots that can develop in more than one place along the stems. The alismatids have adapted to thrive in oceans, temperate zones, deserts, the tropics, and even glacial regions.
Like the earliest monocots, many of the alismatid monocots are aquatic, and some grow completely submerged. Apart from the sweet-flag family of wetlands plants, all the alismatid families are in Alismatales. Some of the plants in this order are invasive aquatic weeds that can disrupt and destabilize ecosystems. Others grow in a variety of habitats, especially plants in the aroid family. This family includes the titan arum, with the world's largest unbranched inflorescence, and also the world's smallest flowering plant, duckweed.
Glossary
From the glossary of botanical terms:
annual: a plant species that completes its life cycle within a single year or growing season
basal: attached close to the base (of a plant or an evolutionary tree diagram)
climber: a vine that leans on, twines around or clings to other plants for vertical support
herbaceous: not woody; usually green and soft in texture
perennial: not an annual or biennial
woody: hard and lignified; not herbaceous
The APG IV system is the fourth in a series of plant taxonomies from the Angiosperm Phylogeny Group. In this system, the alismatids are basal within the monocots.
Alismatid families
See also
List of plant family names with etymologies
Notes
Citations
References
See the terms of their Creative Commons license.
See the terms of their license.
Systematic
Alismatid
Alismatid families
alismatid families
Alismatales | List of alismatid families | Biology | 435 |
14,777,697 | https://en.wikipedia.org/wiki/HCN2 | Potassium/sodium hyperpolarization-activated cyclic nucleotide-gated ion channel 2 is a protein that in humans is encoded by the HCN2 gene.
Interactions
HCN2 has been shown to interact with HCN1 and HCN4.
Function
The function of the channel is not known although its activation by hyperpolarization alludes to the funny channels in the sinoatrial node of the heart (which form the basis of spontaneous generation of electrical rhythm). These channels have recently been associated with chronic pain and blocking the gene is associated with resolution of neuropathic episodes of pain.
See also
Cyclic nucleotide-gated ion channel
References
Further reading
External links
Ion channels | HCN2 | Chemistry | 142 |
58,177,213 | https://en.wikipedia.org/wiki/Unimicron | Unimicron Technology Corporation (Unimicron; ) is a printed circuit board (PCB) manufacturer headquartered in Taiwan. The company produces PCBs, high density interconnection (HDI) boards, flexible PCBs, rigid flex PCBs, integrated circuit (IC) carriers, and others. In addition, it provides testing and burn-in services of IC substrates and PCBs. Applications of its products and services include liquid crystal display (LCD) monitors, personal computers (PCs) and peripheral products, notebook computers, network cards, facsimile machines, scanners, mobile phones, personal digital assistants (PDAs), and others. Unimicron has manufacturing sites and/or service centers in Taiwan, China, Germany, and Japan.
Overview
Unimicron, a subsidiary of United Microelectronics Corporation, started in 1990, grew to global rank of 6th in 2006, and became global No. 1 in the PCB industry in 2009 and 2010. Unimicron arrived at a second position in the 2012 global PCB market with a market share of 3.7% and $2.4 billion in revenue.
References
External links
Official Website
PCB Assembly
1990 establishments in Taiwan
Companies based in Taoyuan City
Electronics companies established in 1990
Printed circuit board manufacturing | Unimicron | Engineering | 266 |
2,902,603 | https://en.wikipedia.org/wiki/26%20Andromedae | 26 Andromedae, abbreviated 26 And, is a binary star system in the constellation Andromeda. 26 Andromedae is the Flamsteed designation. It has a combined apparent visual magnitude of 6.10, which is near the lower limit of visibility to the naked eye. The distance to this system can be estimated from its annual parallax shift of , which yields a distance of about 600 light years. At that distance, the visual magnitude of the stars is diminished from an extinction of 0.04 due to interstellar dust. The system is moving further from the Earth with a heliocentric radial velocity of +3.3 km/s.
The magnitude 6.11 primary, component A, is a B-type main-sequence star with a stellar classification of B8 V. The star has 3.54 times the mass of the Sun and 3.76 times the Sun's radius. It is around 95 million years old and is spinning with a projected rotational velocity of 18 km/s. 26 And is radiating 219 times the Sun's luminosity from its photosphere at an effective temperature of 11,939 K. It displays an infrared excess that suggests a circumstellar debris disk orbiting at a distance of from the star with a temperature of 75 K.
The fainter secondary, component B, is a magnitude 9.70 star located from the primary. It is an F-type main-sequence star with a class of F3 V that shows an unexplained long term variability.
One of the components of this system displays a slight photometric variation with a period of 3.16 days. This may be caused by pulsation or an ellipsoidal variation. This system's X-ray emission hasn't been detected yet, with an upper limit of Lx < 29.79 erg/s.
References
External links
Image 26 Andromedae
B-type main-sequence stars
F-type main-sequence stars
Spectroscopic binaries
Suspected variables
Circumstellar disks
Andromeda (constellation)
Durchmusterung objects
Andromedae, 26
001438
001501
0070 | 26 Andromedae | Astronomy | 449 |
23,777,463 | https://en.wikipedia.org/wiki/G-Book | G-Book was a telematics subscription service provided by Toyota Motor Corporation in Japan for its Toyota- and Lexus-branded vehicles. G-Book allowed users to link with cellphones (such as the Toshiba T003 cellphone), personal digital assistants (PDA)'s, personal computers (PC) and G-Book equipped cars across Japan. It is based on the former GAZOO infrastructure (renamed Toyota Media Service Corporation) of Toyota's membership-based information service and membership system, and it provides interactive information services via vehicle installed touch-screen wireless communication terminals. It also incorporates information from Toyota Mapmaster Inc. which updates digital mapping information and is used by various international companies.
The subscription service replaces the need to periodically update in-car navigation systems that use CD, or DVD installed maps that must be updated with the latest information. The maps are sent by internet connections established through the drivers cellphone with a data download plan associated with the cellphone.
A G-Book application can be installed on select mobile devices, thereby providing the technology without having to purchase a vehicle installed with the technology.
A proprietary service with additional functions for the Lexus division, G-Link, debuted on Japan-market Lexus models starting in model year 2006. Toyota made available G-Book devices as optional equipment in all Japanese domestic market Toyota, Daihatsu and Lexus vehicles starting with model year 2007. An article posted by "Response.jp" stated in an article on July 15, 2009 that Toyota was introducing G-Book in a specially identified Toyota Camry to be sold in Beijing, China. As of November 2009 the G-Book-equipped Camry is available in Shanghai as well. G-Book was also introduced on Lexus models in China in 2009.
In Japan (T-Connect Japan ), and recently in Middle East countries (Bahrain, Jordan, Kuwait, Lebanon, Oman, Qatar and UAE) T-Connect is being offered as a download from Apple's AppStore and Google Play as a subscription telematics service, which uses the G-Book architecture.
G-Book services were discontinued on 31 March 2022.
Technology
There are three versions of G-Book being offered; G-Book mX (and G-Book mX Pro), G-Book Alpha (and G-Book Alpha Pro) and G-Book.
Some of the services G-Book offers are a Safety and Security service, which aids in requesting a tow truck and vehicle location service, Live Navigation where an operator gives turn-by-turn directions, Information Service which provides news, weather forecasts and stock market information, Communication Service that offers the ability to send and receive web based e-mail, and post and read on message boards, E-commerce Service, that allows merchandise to be purchased from the GAZOO Shopping Mall, and a live operator is available through OSS (Operator Support Service) for various issues.
One of the features offered exclusively on G-Book mX is Probe Communication Traffic Information. According to the press release from Toyota dated April 10, 2007, "This unique Toyota traffic information service gathers driving data – such as speed and position – from vehicles equipped with G-Book mX to provide drivers with alternate routes for avoiding traffic congestion. Because it makes use of the on-board DCM (data communications module), the information gathering capability of this service is superior to similar systems, which rely solely on cell phones, and efficiently stores information about traffic congestion in real time at the G-Book Center. In this way the Probe Communication Traffic Information service supplements Vehicle Information and Communication System (VICS) information with updates on traffic congestion, providing drivers with highly accurate predictions about the current traffic situation and suggestions for the best alternate routes to take." This feature is being marketed as an ability to drive eco-friendly, by helping to avoid pollution created by cars idling in traffic and allowing the driver to reach their destination sooner, and affording the opportunity to turn the car off, limiting emissions being added to the atmosphere.
The wireless communications for Japan-market cars are handled by the DCM and transmits and receives information on the wireless network owned by Japanese telecommunications provider KDDI Corporation headquartered in Okinawa. The cellular platform used is the CDMA2000 1x (CDMA 1X) method, and it is possible to receive up to 144 kbit/s data. The same DCM is used for China-market models, thus the network provider for China-market G-Book services is China Telecom. Map updates and music downloads are not available for China-market G-Book-enabled cars, and traffic information is only available in Shanghai, Beijing, Guangzhou, and Shenzhen.
G-Book Alpha Pro, mX Pro DCM-only, and CDMA2000 1xEV-DO (CDMA 1X WIN) can send up to 2.4 Mbit/s of data, and the DCM supports hands-free calls. The DCM model is also equipped with its own GPS receiver and features, to track a stolen vehicle, and it also has an emergency notification ability to transmit the location of airbag deployment.
Secure Digital (SD) card-compatible terminal
According to a press release from Toyota dated 28 August 2002 "Navigational maps and the on-board terminal's basic software are stored in a Secure Digital (SD) card. The card can be inserted into "E-TOWER" terminals at convenience stores and other locations to download local or new maps or to upgrade the on-board terminal's basic software. Music and games can also be downloaded, and the SD card is compatible with commercially available audio players, digital cameras and PDAs that use SD cards, making it possible to share content such as music files, images and games." E-Tower locations can be found at numerous locations, including Circle K of Japan.
G-Link
Offered at Lexus' Japanese domestic market launch in 2005, G-Link is the proprietary Lexus telematics system for the Japanese market. G-Link has a different software configuration versus G-Book, particularly in its link to the 24-hour Lexus Owner's Desk hotline, and is offered standard for the first three years of ownership. Other aspects of the system at its 2005 launch were based on G-Book Alpha capabilities. The G-Link software runs off of the vehicle's hard disc drive navigation system and song library, and includes traffic updates, HelpNet compatibility, and the G-Security service. The G-Security service includes cellphone notification of vehicle lock and position status. A G-Sound music distribution service offers samples and downloading to the vehicle's hard disc drive of MP3s from different genres. A U.S. equivalent of the G-Link system with similar but not identical functionality, called Lexus Enform with Safety Connect, was launched in 2009.
In 2006, Japanese media reported that a Lexus-branded cellphone was also being produced with compatibility for the G-Link system. This cellphone service would be produced in conjunction with the KDDI telecommunications service provider, and is called "au", using Apple and Sony products.
Related versions
Toyota is working with other Japanese car manufacturers, such as Mitsubishi, Subaru and Daihatsu to provide the service in the Japanese language. Mazda has also agreed to offer the service in Japan, with an intent to install the service starting with the 2005 model. Competing services are called "Nissan Car Wings", and Internavi "Internavi Premium Club (Japanese)" by Honda. In the U.S., the Safety Connect system was produced based on the G-Book system architecture, with similar functionality, along with an expanded Lexus Enform service.
The G-Book feature is similar to "W44T" offered in Japan by Toshiba, and "Pipit" in an agreement with Toyota and Willcom in Japan.
See also
()
()
Bluetooth
BMW Assist
CarWings
Fiat Blue&Me
Ford Sync
GM MyLink
Hyundai Blue Link
Internavi
Kia UVO
Mercedes COMAND APS
Microsoft Auto
MSN Direct
MyFord Touch
OnStar
Toyota Entune (USA)
Vehicle-to-vehicle
References
External links
Mazda G-Book official website
Subaru G-Book official website
G-Book listing - list of all Toyota vehicles that have G-Book offered as an option
Lexus G-Link - official website for the Lexus telematics service
G-Link listing - list of Lexus vehicles and Bluetooth compatibility with G-Link
Overview of Toyota's G-Book telematics service
Vehicle telematics
Automotive technology tradenames
Wireless
Lexus
Toyota
Information systems
Warning systems
Road transport in Japan
Intelligent transportation systems
Telecommunications-related introductions in 2006
Audiovisual introductions in 2006
Japanese inventions
2006 establishments in Japan | G-Book | Technology,Engineering | 1,786 |
41,871,131 | https://en.wikipedia.org/wiki/Wooded%20meadow | Wooded meadows (also named wood-meadows, park meadows, etc.) are ecosystems in temperate forest regions. They are sparse natural stands with a regularly mowed herbaceous layer.
While frequent throughout Europe during the Medieval period and before, wooded meadows have largely disappeared. Wooded meadows originated with the practices of hunter-gatherer communities. They were important in terms of social organization around a natural resource and determined much of the community's interactions with the natural world. In the early 20th century, wooded meadows were used for fruit cultivation in Sweden; however, their prevalence has decreased substantially due to changes in land management and a movement toward more intensive types of agroecosystems. The more typical, calcicolous wooded meadows are common around the Baltic Sea.
Wooded meadows have high species richness. In some of the current Estonian wooded meadows, world-record species densities have been recorded (up to 76 species of vascular plants per square meter).
Literature
Kull, Kalevi; Kukk, Toomas; Lotman, Aleksei 2003. When culture supports biodiversity: The case of wooded meadow. In: Roepstorff, Andreas; Bubandt, Nils; Kull, Kalevi (eds.) 2003. Imagining Nature: Practices of Cosmology and Identity. Aarhus: Aarhus University Press, 76–96. (pdf)
References
External links
On wooded meadows at the Estonian Seminatural Community Conservation Association site
Ecology
Grasslands
Habitats
Land management
Meadows | Wooded meadow | Biology | 301 |
9,871,777 | https://en.wikipedia.org/wiki/Pahutoxin | Pahutoxin, formerly called ostracitoxin, is a neurotoxin present in the mucous secretions of boxfish (Ostraciidae) skin, while under stress. It is an ichthyotoxic, hemolytic, nonpeptide (which is relatively unusual, although similar to tetrodotoxin in this way) toxin. It is heat-stable and non-dialyzable, that is, foamed in aqueous solutions, and is toxic to various biological systems. It is unique among known fish poisons. It is toxic to other boxfish as well and looks like red tide and sea cucumber toxins in general properties. Although it is not recommended, it is a growing trend to keep boxfish in a home aquarium. Members of the family Ostraciidae secrete an ichthyotoxic mucus from their skin when stressed or disturbed.
The boxfish must be alive to synthesize its bodily chemicals into the toxin, therefore it cannot release its toxin after it dies. It may, however, have residual toxin if it were in the process of releasing toxin when it died.
References
Ichthyotoxins
Quaternary ammonium compounds
Acetate esters
Neurotoxins
Cationic surfactants
Choline esters | Pahutoxin | Chemistry | 271 |
1,145,930 | https://en.wikipedia.org/wiki/Lucas%E2%80%93Carmichael%20number | In mathematics, a Lucas–Carmichael number is a positive composite integer n such that
If p is a prime factor of n, then p + 1 is a factor of n + 1;
n is odd and square-free.
The first condition resembles Korselt's criterion for Carmichael numbers, where -1 is replaced with +1. The second condition eliminates from consideration some trivial cases like cubes of prime numbers, such as 8 or 27, which otherwise would be Lucas–Carmichael numbers (since n3 + 1 = (n + 1)(n2 − n + 1) is always divisible by n + 1).
They are named after Édouard Lucas and Robert Carmichael.
Properties
The smallest Lucas–Carmichael number is 399 = 3 × 7 × 19. It is easy to verify that 3+1, 7+1, and 19+1 are all factors of 399+1 = 400.
The smallest Lucas–Carmichael number with 4 factors is 8855 = 5 × 7 × 11 × 23.
The smallest Lucas–Carmichael number with 5 factors is 588455 = 5 × 7 × 17 × 23 × 43.
It is not known whether any Lucas–Carmichael number is also a Carmichael number.
Thomas Wright proved in 2016 that there are infinitely many Lucas–Carmichael numbers. If we let denote the number of Lucas–Carmichael numbers up to , Wright showed that there exists a positive constant such that
.
List of Lucas–Carmichael numbers
The first few Lucas–Carmichael numbers and their prime factors are listed below.
References
External links
Eponymous numbers in mathematics
Integer sequences | Lucas–Carmichael number | Mathematics | 320 |
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