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41,559,701 | https://en.wikipedia.org/wiki/68%20Cygni | 68 Cygni is the Flamsteed designation for a star in the constellation Cygnus. Located approximately distant, the star is a hot blue giant of spectral type O7.5IIIn((f)), a massive star that is likely currently expanding to become a supergiant. The star is surrounded by a ring-shaped nebula (likely a Strömgren sphere) named Sharpless 2-119 (Clamshell nebula).
68 Cygni is currently classified as a rotating ellipsoidal variable, varying between apparent magnitudes 4.98 and 5.09, although the classification as a rotating ellipsoidal variable is subject to controversy. Barely visible to the naked eye, the star is likely to have a mass of around 26 solar masses and a temperature of approximately 34,000 kelvins, although many of the star's physical parameters are subject to uncertainties due to the unclear nature of the system.
Naming
Being visible to the naked eye, 68 Cygni would have been observable since ancient times, but the first known cataloging and designation of the star was by Johann Bayer, who assigned it the Bayer designation A Cygni. Bayer grouped stars into six magnitude groupings (1st- through 6th-magnitude) and assigned Greek letters to the brightest 24 stars in these groupings, sorted by right ascension within groups. When he ran out of Greek letters, Bayer then moved on to Latin letters; thus, 68 Cygni was the 25th star Bayer designated in Cygnus.
The star was later observed by John Flamsteed, who cataloged naked-eye stars by constellation. Contrary to popular belief, Flamsteed did not assign the stars Flamsteed designations; rather, the French astronomer Joseph Jérôme de Lalande assigned Flamsteed numbers to stars in each constellation in order of right ascension. Since this star was the 68th star by right ascention in Cygnus, it was numbered 68 Cygni, the designation by which this star is most commonly known today, as most Latin-letter Bayer designations are no longer in common use.
After the star was discovered to be variable, it was assigned a variable star designation. As the 1809th variable star without a Bayer designation to be discovered in Cygnus, 68 Cygni was assigned the designation V1809 Cygni in 1984.
Observation
68 Cygni has an apparent magnitude of approximately 5.0, making the star a fairly inconspicuous star in the night sky, and nearly invisible when the moon is full. With a new moon, according to the Bortle scale, the star cannot be easily seen with the naked eye from polluted areas or with a full moon, but can be seen from suburban areas when overhead.
In the night sky, 68 Cygni is located west of the main asterism of Cygnus, approximately seven degrees east-southeast of the first-magnitude star Deneb. This is near the midpoint of the imaginary line between the 3rd-magnitude stars Xi Cygni and Rho Cygni. The star can also be found by continuing north along the line between the stars Zeta Cygni, Upsilon Cygni, Tau Cygni, and Sigma Cygni, as 68 Cygni is the first easily visible naked-eye star one will come to.
Properties
According to the star's measured parallax of , it is located approximately distant. A more complex statistical analysis of the likely distance gives a value between and .
68 Cygni is a massive blue giant of spectral type O7.5IIIn((f)). Such massive stars only remain in the main sequence phase for a few million years, less than a thousandth of the expected main sequence lifetime of the sun. 68 Cygni has already expanded off the main sequence to become a blue giant, and is likely expanding to become a blue supergiant, although for very hot stars such as 68 Cygni evolution to the giant and supergiant classes does not indicate exhaustion of core hydrogen, nor is it accompanied by a large increase in luminosity. Instead the products of fusion burning are distributed throughout the star by convection and rotational mixing, producing helium and nitrogen lines in the spectrum, leading to an increase in the thickness of the stellar wind, and accompanied by a modest expansion and cooling of the star. The "n" in the spectral type indicates the presence of broad absorption lines due to how rapidly the star is spinning. The "((f))" indicates strong absorption in the He II spectral lines and weak N III emission lines.
The star is currently tentatively classified as a rotating ellipsoidal variable, varying between magnitudes 4.98 and 5.09. Rotating ellipsoidal variables are binary systems in which the constituent components are distorted into ellipses due to fast rotation rates, and as the two stars orbit each other, the surface area of the star facing Earth changes, causing variations in brightness. However, the actual cause of the variability, and even whether or not there is a companion, is uncertain. No companion has ever been directly detected, but its existence has been inferred from spectral line variations in the primary O-type star. A period of 5.1 days has been assigned for the orbit of the binary, which is approximately the same as the rotation period of the star. Unlike typical rotating ellipsoidal variables, there is no clearly defined period in the variations in brightness. Data derived from the assumption of a binary system, for example the mass, are highly uncertain due to the lack of information about the inclination or eccentricity of the orbit, or even whether there is a companion.
The spectral lines of 68 Cygni vary erratically, but possibly with a period around 5 days. The lines frequently show P Cygni profiles with both an absorption and emission component slightly offset due to doppler shifting. The emission component arises primarily in the stellar wind and the absorption component in the photosphere. The emission components of the spectral lines are largely constant, but the absorption components vary, leading to changes in the line profiles. This is strongest in the ultraviolet part of the electromagnetic spectrum and has been extensively studied by the International Ultraviolet Explorer satellite. The type and scale of the spectroscopic variations indicates large-scale structures within the stellar wind.
The mass of the star is likely to be around 26 solar masses, according to a 2011 study by Ducati, Penteado, and Turcati. However, due to the uncertain nature of the binary system hypothesis, the true mass could be much different than this. If the star actually has a mass of 51 solar masses (the median mass reported by Hohle, Neuhäuser, and Schutz in 2010), the star's bolometric luminosity would be over 1 million solar luminosities, making it among the most luminous stars known, although data to support this mass is tenuous at best, and it has an uncertainty of (40%).
Sharpless 2-119 (Clamshell nebula)
68 Cygni is known to be surrounded by a ring-shaped nebula, named Sharpless 2-119 (Clamshell nebula). Although it was originally proposed that this nebula was formed from 68 Cygni's stellar wind, it now appears that the nebula is simply a Strömgren sphere that is being ionized by 68 Cygni. Instead, the stellar wind is likely, due to the star's high velocity through space, forming a bow shock.
Notes
References
Cygni, A
Cygnus (constellation)
Emission-line stars
Cygni, 68
Cygni, V1809
O-type giants
Rotating ellipsoidal variables
105186
203064
8154
BD+43 3877 | 68 Cygni | Astronomy | 1,579 |
5,340,708 | https://en.wikipedia.org/wiki/Carling%20%28sailing%29 | In shipbuilding, carlings are two pieces of timber laid fore and aft under the deck of a ship, from one beam to another, directly over the keel. They serve as a foundation for the whole body of the ship; on these the ledges rest, whereon the planks of the deck, and other structures are fastened. The ends of the carlings are let culvertail into the beams.
The great carlings are those on which the mainmast stands. There are also carlings of the capstan, among others.
Carling knees are timbers going traversely, from the sides to the hatchway, serving to sustain the deck on both sides.
References
Shipbuilding
Sailboat components
Sailing ship components | Carling (sailing) | Engineering | 145 |
70,917,667 | https://en.wikipedia.org/wiki/Exceptional%20point | In quantum physics, exceptional points are singularities in the parameter space where two or more eigenstates (eigenvalues and eigenvectors) coalesce. These points appear in dissipative systems, which make the Hamiltonian describing the system non-Hermitian.
Photonics
The losses in photonic systems, are a feature used to study non-Hermitian physics. Adding non-Hermiticity (such as dichroism) to photonic systems which present Dirac points transforms these degeneracy points into pairs of exceptional points. This has been demonstrated experimentally in numerous photonic systems such as microcavities and photonic crystals. The first demonstration of exceptional points was made by Woldemar Voigt in 1902 for optical modes in crystals.
Fidelity and fidelity susceptibility
In condensed matter and many-body physics, fidelity is often used to detect quantum phase transitions in parameter space. The definition of fidelity is the inner product of the ground state wave functions of two adjacent points in parameter space, , where is a small quantity. After series expansion, , the first-order correction term of fidelity is zero, and the coefficient of the second-order correction term is called the fidelity susceptibility. The fidelity susceptibility diverges toward positive infinity as the parameters approach the quantum phase transition point.
For the exceptional points of non-Hermitian quantum systems, after appropriately generalizing the definition of fidelity,
the real part of the fidelity susceptibility diverges toward negative infinity when the parameters approach the exceptional points.
For non-Hermitian quantum systems with PT symmetry, fidelity can be used to analyze whether exceptional points are of higher-order. Many numerical methods such as the Lanczos algorithm, Density Matrix Renormalization Group (DMRG), and other tensor network algorithms are relatively easy to calculate only for the ground state, but have many difficulties in computing the excited states. Because fidelity only requires the ground state calculations, this approach allows most numerical methods to analyze non-Hermitian systems without excited states, and find the exceptional point, as well as to determine whether it is a higher-order exceptional point.
See also
Dirac cones
Non-Hermitian quantum mechanics
References
Quantum mechanics
Photonics | Exceptional point | Physics | 459 |
38,144,618 | https://en.wikipedia.org/wiki/3-Deoxy-D-arabino-heptulosonic%20acid%207-phosphate | {{DISPLAYTITLE:3-Deoxy-D-arabino-heptulosonic acid 7-phosphate}}
3-Deoxy--arabino-heptulosonic acid 7-phosphate (DAHP) is a 7-carbon ulosonic acid. This compound is found in the shikimic acid biosynthesis pathway and is an intermediate in the production of aromatic amino acids.
Phosphoenolpyruvate and erythrose-4-phosphate react to form 3-deoxy--arabino-heptulosonate-7-phosphate (DAHP), in a reaction catalyzed by the enzyme DAHP synthase.
DAHP is then transformed to 3-dehydroquinate (DHQ), in a reaction catalyzed by DHQ synthase. Although this reaction requires nicotinamide adenine dinucleotide (NAD) as a cofactor, the enzymic mechanism regenerates it, resulting in the net use of no NAD.
The mechanism of ring closure is complex, but involves an aldol condensation at C-2 and C-7.
Metabolic engineering has improved production of DAHP by Escherichia coli. The first step, condensation of 3-deoxy--arabino-heptulosonic acid 7-phosphate (DAHP) from PEP/E4P, uses three isoenzymes AroF, AroG, and AroH. Each one of these has its synthesis regulated from tyrosine, phenylalanine, and tryptophan, respectively. These isoenzymes all have the ability to help regulate synthesis of DAHP by the method of feedback inhibition. This acts in the cell by monitoring the concentrations of each of the three aromatic amino acids. When there is too much of any one of them, that one will allosterically control the DAHP synthetase by “turning it off”. With the first step of the common pathway shut off, synthesis of the three amino acids can not proceed. The rest of the enzymes is in the common pathway (conversion of DAHP to chorismate).
References
External links
Carboxylic acids
Organophosphates
Heptoses
Monosaccharide derivatives | 3-Deoxy-D-arabino-heptulosonic acid 7-phosphate | Chemistry | 475 |
45,351,298 | https://en.wikipedia.org/wiki/Gustav%20Hahn | Gustav Hahn (27 July 1866 – 1 December 1962) was a German Canadian painter, muralist and interior decorator who pioneered the Art Nouveau style in Canada. Hahn was also an amateur astronomer, and his father, Otto Hahn, owned a collection of meteorites.
Life
Hahn was born in Reutlingen, then in the German Confederation. As a young man, he attended art school in Stuttgart. In 1888 he moved to Toronto in Canada, where he started to work as a designer in an interior decorating firm. Hahn painted murals in public buildings such as the Ontario Legislature and the Toronto Old City Hall, as well as churches and residences.
Hahn's major works include the depiction of the 1913 Great Meteor Procession (titled Meteoric Display of February 9, 1913, as seen near High Park) and Hail Dominion (1906). Hail Dominion was a part of a proposal to make a series of murals for the Parliament buildings in Ottawa with the Toronto painter George A. Reid. For Hail Dominion Hahn used his wife and elder daughters as models for Mother Canada.
Hahn taught at the Ontario College of Art, the Royal Ontario Museum, and Central Technical School. His daughter, Sylvia Hahn, also became a muralist.
His brother was Emanuel Hahn.
See also
List of German Canadians
References
19th-century Canadian painters
Canadian male painters
20th-century Canadian painters
Amateur astronomers
Art Nouveau painters
Canadian muralists
Immigrants to Canada
People from Reutlingen
1866 births
1962 deaths
19th-century Canadian male artists
20th-century Canadian male artists
Members of the Royal Canadian Academy of Arts
Emigrants from the German Empire | Gustav Hahn | Astronomy | 319 |
3,005,228 | https://en.wikipedia.org/wiki/Nuclear%20Explosions%20for%20the%20National%20Economy | Nuclear Explosions for the National Economy (; sometimes referred to as Program #7) was a Soviet program to investigate peaceful nuclear explosions (PNEs). It was analogous to the United States program Operation Plowshare, although the Soviet one consists of 124 tests.
One of the better-known tests was Chagan of January 15, 1965. Radioactivity from the Chagan test was detected over Japan by both the U.S. and Japan in apparent violation of the 1963 Partial Test Ban Treaty (PTBT). The United States complained to the Soviets, but the matter was dropped.
History
In November 1949, shortly after the test of their first nuclear device on September 23, 1949, Andrey Vyshinsky, the Soviet representative to the United Nations, delivered a statement justifying their efforts to develop their own nuclear weapons capability. He said:
However the USSR did not immediately follow the U.S. lead in 1958 in establishing a program. Presumably, their position in support of a comprehensive nuclear testing ban stalled any efforts to establish such a program until the mid-1960s.
When Nuclear Explosions for the National Economy was finally formally established, Alexander D. Zakharenkov, a chief weapons designer, was appointed head of the program. Initially, the Soviet program was focused on two applications, nuclear excavation and petroleum stimulation, similar to the U.S. program. However, interest in other applications quickly developed, and within five years the Soviet program was actively exploring six or seven applications involving participation by some ten government departments.
Once underway the Soviets conducted a much more vigorous program than the Americans' Operation Plowshare, consisting of some 156 nuclear tests, some with multiple devices, between 1965 and 1989. These tests were similar in aims to the American effort, with the exception that six of the shots were considered of an applied nature, that is they were not tests as such, but were used to put out runaway gas well fires and a methane blow out.
There were in fact two programs:
"Employment of Nuclear Explosive Technologies in the Interests of National Economy", also referred to as "Program 6", involved industrial underground PNEs and testing of new PNE technologies. As part of the program, 124 tests with 135 devices were conducted. Primary objectives of the program were water reservoir development, dam and canal construction, and creation of underground cavities for toxic waste storage.
"Peaceful Nuclear Explosions for the National Economy", also referred to as "Program 7", involved testing of industrial nuclear charges for use in peaceful activities. Nuclear detonations were conducted with the stated purpose of searching for useful mineral resources with reflection seismology, breaking up ore bodies, stimulating the production of oil and gas, and forming underground cavities for storing the recovered oil and gas. The "Program" numbers come from the USSR's classification system of nuclear explosions, the first five programs designating various phases of nuclear weapon development.
All together, the Program 7 conducted 115 nuclear explosions. Among them:
39 explosions for geological exploration (trying to find new natural gas deposits by studying seismic waves produced by small nuclear explosions)
25 explosions to intensify oil and gas debits
22 explosions to create underground storage for natural gas
5 explosions to extinguish large natural gas fountains that were burning
4 explosions to create channels and dams (including the Chagan test in Kazakhstan, and the Taiga test on the potential route of the Pechora–Kama Canal)
2 explosions to crush ore in open-pit mines
2 explosions to create underground storage for toxic wastes
1 explosion to facilitate coal mining in an underground mine
19 explosions for research purposes (studying possible migration of the radioactivity from the place of the explosions).
These explosions were financed by various ministries: 51 explosions were financed by the Ministry for Geology, 26 explosions were financed by the Ministry for Natural Gas, 13 explosions were financed by the Ministry for Oil, 19 explosions were financed by the MinSredMash itself (the predecessor of the Federal Atomic Energy Agency). There were two large explosions of 140 kilotons and 105 kilotons; all others were relatively small with an average yield of 12.5 kilotons. For example, one 30-kiloton explosion was used to close the Uzbekistan Urtabulak gas well in 1966 that had been blowing since 1963, and on May 11th 1968 a 47-kiloton explosive was used to seal a higher pressure blowout at the nearby Pamuk gas field, Gas fire blowouts like this occurred three more times over the following years, On July 9th 1972 a 3.8-Kiloton explosive was used in Krestishche gas field in Ukraine, And again in the same gas field on August 6th 1972 where a 5-Kiloton explosive was used (a separate well from the July operation), And another was used at the Kumzhinskoye gas field in Northern Russia, Where the fire at this site had been burning for more than a year before being extinguished by a 37.5 Kiloton explosive on December 18th 1981, These successful experiments were later cited as possible precedents for stopping the Deepwater Horizon oil spill.
The last nuclear explosion by the Program 7, codenamed Rubin-1, was performed in Arkhangelsk Oblast on September 6, 1988. The explosion was a part of a seismic program for geological exploration. The Soviets agreed to stop their PNE program at the end of 1988 as a result of then-president Mikhail Gorbachev's disarmament initiative.
There are proponents for continuing the PNE programs in modern Russia. They (e.g. A. Koldobsky) state that the program has already paid for itself and saved the USSR billions of rubles and can save even more if it would continue. They also allege that the PNE is the only feasible way to put out large fountains and fires on natural gas deposits, and it is the safest and most economically viable way to destroy chemical weapons.
Their opponents, including Alexey Yablokov, state that all PNE technologies have non-nuclear alternatives and that many PNEs actually caused nuclear disasters.
Problems
Among the catastrophes was the Kraton-3 explosion in Vilyuy, Yakutia, in 1978, that was supposed to unearth diamond-rich ores. Instead, the amount of diamonds was insignificant but the plutonium pollution of water was much higher than predicted. According to the anti-nuclear activist Alexei Yablokov, the level of plutonium in the drinking water of Vilyuy region 20 years after the explosion is ten thousand times higher than the maximal sanitary norm.
Another catastrophe resulted from the Globus-1 explosion near the village of Galkino at , 40 kilometers from Kineshma city on September 19, 1971. It was a small underground explosion of 2.5 kilotons that was a part of the seismological program for oil and gas exploration. Unexpectedly a large amount of radioactive gases escaped through cracks in the ground, creating a significant radioactive hot spot two kilometers in diameter, in the relatively densely populated area of European Russia. A small tributary of the Volga, the Shacha, changed its location and threatened to flood the explosion site. This could have led to nuclear pollution of the entire Volga region. Some engineers suggested building a sarcophagus (similar to the Chernobyl's "Object Shelter") covering the site, and excavating a 12 km channel to shift the Shacha river away from the place of the explosion, but the plans appeared prohibitively expensive.
The experiments ended with the adoption of a unilateral moratorium on nuclear weapons testing at Soviet sites in 1989. Although this primarily was designed to support Mikhail Gorbachev's call for a worldwide ban on nuclear weapons tests, the Russians apparently applied the moratorium to peaceful nuclear explosions as well.
Implications
The Soviet PNE program was many times larger than the U.S. Plowshare program in terms of both the number of applications explored with field experiments and the extent to which they were introduced into industrial use. Several PNE applications, such as deep seismic sounding and oil stimulation, were explored in depth and appeared to have had a positive cost benefit at minimal public risk. Several others, such as storage, developed significant technical problems that cast a shadow on their general applicability. Some, such as closure of runaway gas wells, demonstrated a unique technology that may yet find application as a last resort. Still others were the subject of one or two tests but were not explored further for reasons that have never been explained. Overall, the program represented a significant technical effort to explore what was seen at the time to be a promising new technology, and it generated a large body of data, although only a small fraction of it has been made public.
See also
Peaceful nuclear explosions
Soviet atomic bomb project
1971 Soviet nuclear tests
Категория:Мирные ядерные взрывы на территории СССР (Articles on individual explosions in Russian Wikipedia)
Notes
References
External links
USSR Nuclear Weapons Tests and Peaceful Nuclear Explosions. 1949 through 1990, an official publication of Federal Atomic Energy Agency.
1966 Urta-Bulak well #11 blowout
Cold War history of the Soviet Union
Economy of the Soviet Union
Peaceful nuclear explosions | Nuclear Explosions for the National Economy | Chemistry | 1,903 |
24,508,936 | https://en.wikipedia.org/wiki/Gymnopilus%20luteocarneus | Gymnopilus luteocarneus is a species of mushroom-forming fungus in the family Hymenogastraceae.
Description
The cap is in diameter.
Habitat and distribution
Gymnopilus luteocarneus grows solitary to scattered, on conifer logs. It has been found in California in November.
See also
List of Gymnopilus species
References
luteocarneus
Fungi of North America
Fungi described in 1969
Taxa named by Lexemuel Ray Hesler
Fungus species | Gymnopilus luteocarneus | Biology | 101 |
14,569,866 | https://en.wikipedia.org/wiki/Abu%20Sayda%20chlorine%20bombing | The Abu Sayda bombing was a chlorine car bombing attack that occurred on 15 May 2007, in an open-air market in the Iraqi Diyala Governorate village of Abu Sayda. The attack killed up to 45 people and wounded 60 more in the Shia village, the highest death toll of all chlorine bombings in Iraq. Iraqi and American military sources initially denied the use of chlorine.
References
2007 murders in Iraq
Chemical weapons attacks
Bombings in the Iraqi insurgency (2003–2011)
Car and truck bombings in Iraq
Chemical terrorism
Marketplace attacks in Iraq
Mass murder in 2007
May 2007 events in Iraq
Terrorist incidents in Iraq in 2007
Violence against Shia Muslims in Iraq
War crimes in the Iraq War
Diyala Governorate in the Iraq War
Car and truck bombings in 2007 | Abu Sayda chlorine bombing | Chemistry | 153 |
28,716 | https://en.wikipedia.org/wiki/Smelting | Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron, copper, silver, tin, lead and zinc. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal behind. The reducing agent is commonly a fossil-fuel source of carbon, such as carbon monoxide from incomplete combustion of coke—or, in earlier times, of charcoal. The oxygen in the ore binds to carbon at high temperatures, as the chemical potential energy of the bonds in carbon dioxide () is lower than that of the bonds in the ore.
Sulfide ores such as those commonly used to obtain copper, zinc or lead, are roasted before smelting in order to convert the sulfides to oxides, which are more readily reduced to the metal. Roasting heats the ore in the presence of oxygen from air, oxidizing the ore and liberating the sulfur as sulfur dioxide gas.
Smelting most prominently takes place in a blast furnace to produce pig iron, which is converted into steel.
Plants for the electrolytic reduction of aluminium are referred to as aluminium smelters.
Process
Smelting involves more than just melting the metal out of its ore. Most ores are the chemical compound of the metal and other elements, such as oxygen (as an oxide), sulfur (as a sulfide), or carbon and oxygen together (as a carbonate). To extract the metal, workers must make these compounds undergo a chemical reaction. Smelting, therefore, consists of using suitable reducing substances that combine with those oxidizing elements to free the metal.
Roasting
In the case of sulfides and carbonates, a process called "roasting" removes the unwanted carbon or sulfur, leaving an oxide, which can be directly reduced. Roasting is usually carried out in an oxidizing environment. A few practical examples:
Malachite, a common ore of copper is primarily copper carbonate hydroxide Cu2(CO3)(OH)2. This mineral undergoes thermal decomposition to 2CuO, CO2, and H2O in several stages between 250 °C and 350 °C. The carbon dioxide and water are expelled into the atmosphere, leaving copper(II) oxide, which can be directly reduced to copper as described in the following section titled Reduction.
Galena, the most common mineral of lead, is primarily lead sulfide (PbS). The sulfide is oxidized to a sulfite (PbSO3), which thermally decomposes into lead oxide and sulfur dioxide gas (PbO and SO2). The sulfur dioxide is expelled (like the carbon dioxide in the previous example), and the lead oxide is reduced as below.
Reduction
Reduction is the final, high-temperature step in smelting, in which the oxide becomes the elemental metal. A reducing environment (often provided by carbon monoxide, made by incomplete combustion in an air-starved furnace) pulls the final oxygen atoms from the raw metal. The carbon source acts as a chemical reactant to remove oxygen from the ore, yielding the purified metal element as a product. The carbon source is oxidized in two stages. First, carbon (C) combusts with oxygen (O2) in the air to produce carbon monoxide (CO). Second, the carbon monoxide reacts with the ore (e.g. Fe2O3) and removes one of its oxygen atoms, releasing carbon dioxide (). After successive interactions with carbon monoxide, all of the oxygen in the ore will be removed, leaving the raw metal element (e.g. Fe). As most ores are impure, it is often necessary to use flux, such as limestone (or dolomite), to remove the accompanying rock gangue as slag. This calcination reaction emits carbon dioxide.
The required temperature varies both in absolute terms and in terms of the melting point of the base metal. Examples:
Iron oxide becomes metallic iron at roughly 1250 °C (2282 °F or 1523 K), almost 300 degrees below iron's melting point of 1538 °C (2800 °F or 1811 K).
Mercuric oxide becomes vaporous mercury near 550 °C (1022 °F or 823 K), almost 600 degrees above mercury's melting point of -38 °C (-36.4 °F or 235 K), and also above mercury's boiling point.
Fluxes
Fluxes are materials added to the ore during smelting to catalyze the desired reactions and to chemically bind to unwanted impurities or reaction products. Calcium carbonate or calcium oxide in the form of lime are often used for this purpose, since they react with sulfur, phosphorus, and silicon impurities to allow them to be readily separated and discarded, in the form of slag. Fluxes may also serve to control the viscosity and neutralize unwanted acids.
Flux and slag can provide a secondary service after the reduction step is complete; they provide a molten cover on the purified metal, preventing contact with oxygen while still hot enough to readily oxidize. This prevents impurities from forming in the metal.
Sulfide ores
The ores of base metals are often sulfides. In recent centuries, reverberatory furnaces have been used to keep the charge being smelted separately from the fuel. Traditionally, they were used for the first step of smelting: forming two liquids, one an oxide slag containing most of the impurities, and the other a sulfide matte containing the valuable metal sulfide and some impurities. Such "reverb" furnaces are today about 40 meters long, 3 meters high, and 10 meters wide. Fuel is burned at one end to melt the dry sulfide concentrates (usually after partial roasting) which are fed through openings in the roof of the furnace. The slag floats over the heavier matte and is removed and discarded or recycled. The sulfide matte is then sent to the converter. The precise details of the process vary from one furnace to another depending on the mineralogy of the ore body.
While reverberatory furnaces produced slags containing very little copper, they were relatively energy inefficient and off-gassed a low concentration of sulfur dioxide that was difficult to capture; a new generation of copper smelting technologies has supplanted them. More recent furnaces exploit bath smelting, top-jetting lance smelting, flash smelting, and blast furnaces. Some examples of bath smelters include the Noranda furnace, the Isasmelt furnace, the Teniente reactor, the Vunyukov smelter, and the SKS technology. Top-jetting lance smelters include the Mitsubishi smelting reactor. Flash smelters account for over 50% of the world's copper smelters. There are many more varieties of smelting processes, including the Kivset, Ausmelt, Tamano, EAF, and BF.
History
Of the seven metals known in antiquity, only gold regularly occurs in nature as a native metal. The others – copper, lead, silver, tin, iron, and mercury – occur primarily as minerals, although native copper is occasionally found in commercially significant quantities. These minerals are primarily carbonates, sulfides, or oxides of the metal, mixed with other components such as silica and alumina. Roasting the carbonate and sulfide minerals in the air converts them to oxides. The oxides, in turn, are smelted into the metal. Carbon monoxide was (and is) the reducing agent of choice for smelting. It is easily produced during the heating process, and as a gas comes into intimate contact with the ore.
In the Old World, humans learned to smelt metals in prehistoric times, more than 8000 years ago. The discovery and use of the "useful" metals – copper and bronze at first, then iron a few millennia later – had an enormous impact on human society. The impact was so pervasive that scholars traditionally divide ancient history into Stone Age, Bronze Age, and Iron Age.
In the Americas, pre-Inca civilizations of the central Andes in Peru had mastered the smelting of copper and silver at least six centuries before the first Europeans arrived in the 16th century, while never mastering the smelting of metals such as iron for use with weapon craft.
Copper and bronze
Copper was the first metal to be smelted. How the discovery came about is debated. Campfires are about 200 °C short of the temperature needed, so some propose that the first smelting of copper may have occurred in pottery kilns. (The development of copper smelting in the Andes, which is believed to have occurred independently of the Old World, may have occurred in the same way.)
The earliest current evidence of copper smelting, dating from between 5500 BC and 5000 BC, has been found in Pločnik and Belovode, Serbia. A mace head found in Turkey and dated to 5000 BC, once thought to be the oldest evidence, now appears to be hammered, native copper.
Combining copper with tin and/or arsenic in the right proportions produces bronze, an alloy that is significantly harder than copper. The first copper/arsenic bronzes date from 4200 BC from Asia Minor. The Inca bronze alloys were also of this type. Arsenic is often an impurity in copper ores, so the discovery could have been made by accident. Eventually, arsenic-bearing minerals were intentionally added during smelting.
Copper–tin bronzes, harder and more durable, were developed around 3500 BC, also in Asia Minor.
How smiths learned to produce copper/tin bronzes is unknown. The first such bronzes may have been a lucky accident from tin-contaminated copper ores. However, by 2000 BC, people were mining tin on purpose to produce bronze—which is remarkable as tin is a semi-rare metal, and even a rich cassiterite ore only has 5% tin.
The discovery of copper and bronze manufacture had a significant impact on the history of the Old World. Metals were hard enough to make weapons that were heavier, stronger, and more resistant to impact damage than wood, bone, or stone equivalents. For several millennia, bronze was the material of choice for weapons such as swords, daggers, battle axes, and spear and arrow points, as well as protective gear such as shields, helmets, greaves (metal shin guards), and other body armor. Bronze also supplanted stone, wood, and organic materials in tools and household utensils—such as chisels, saws, adzes, nails, blade shears, knives, sewing needles and pins, jugs, cooking pots and cauldrons, mirrors, and horse harnesses. Tin and copper also contributed to the establishment of trade networks that spanned large areas of Europe and Asia and had a major effect on the distribution of wealth among individuals and nations.
Tin and lead
The earliest known cast lead beads were thought to be in the Çatalhöyük site in Anatolia (Turkey), and dated from about 6500 BC. However, recent research has discovered that this was not lead, but rather cerussite and galena, minerals rich in, but distinct from, lead.
Since the discovery happened several millennia before the invention of writing, there is no written record of how it was made. However, tin and lead can be smelted by placing the ores in a wood fire, leaving the possibility that the discovery may have occurred by accident. Recent scholarship however has called this find into question.
Lead is a common metal, but its discovery had relatively little impact in the ancient world. It is too soft to use for structural elements or weapons, though its high density relative to other metals makes it ideal for sling projectiles. However, since it was easy to cast and shape, workers in the classical world of Ancient Greece and Ancient Rome used it extensively to pipe and store water. They also used it as a mortar in stone buildings.
Tin was much less common than lead, is only marginally harder, and had even less impact by itself.
Early iron smelting
The earliest evidence for iron-making is a small number of iron fragments with the appropriate amounts of carbon admixture found in the Proto-Hittite layers at Kaman-Kalehöyük and dated to 2200–2000 BC. Souckova-Siegolová (2001) shows that iron implements were made in Central Anatolia in very limited quantities around 1800 BC and were in general use by elites, though not by commoners, during the New Hittite Empire (~1400–1200 BC).
Archaeologists have found indications of iron working in Ancient Egypt, somewhere between the Third Intermediate Period and 23rd Dynasty (ca. 1100–750 BC). Significantly though, they have found no evidence of iron ore smelting in any (pre-modern) period. In addition, very early instances of carbon steel were in production around 2000 years ago (around the first-century.) in northwest Tanzania, based on complex preheating principles. These discoveries are significant for the history of metallurgy.
Most early processes in Europe and Africa involved smelting iron ore in a bloomery, where the temperature is kept low enough so that the iron does not melt. This produces a spongy mass of iron called a bloom, which then must be consolidated with a hammer to produce wrought iron. Some of the earliest evidence to date for the bloomery smelting of iron is found at Tell Hammeh, Jordan, radiocarbon-dated to .
Later iron smelting
From the medieval period, an indirect process began to replace the direct reduction in bloomeries. This used a blast furnace to make pig iron, which then had to undergo a further process to make forgeable bar iron. Processes for the second stage include fining in a finery forge. In the 13th century during the High Middle Ages the blast furnace was introduced by China who had been using it since as early as 200 b.c during the Qin dynasty. Puddling was also introduced in the Industrial Revolution.
Both processes are now obsolete, and wrought iron is now rarely made. Instead, mild steel is produced from a Bessemer converter or by other means including smelting reduction processes such as the Corex Process.
Environmental and occupational health impacts
Smelting has serious effects on the environment, producing wastewater and slag and releasing such toxic metals as copper, silver, iron, cobalt, and selenium into the atmosphere. Smelters also release gaseous sulfur dioxide, contributing to acid rain, which acidifies soil and water.
The smelter in Flin Flon, Canada was one of the largest point sources of mercury in North America in the 20th century. Even after smelter releases were drastically reduced, landscape re-emission continued to be a major regional source of mercury. Lakes will likely receive mercury contamination from the smelter for decades, from both re-emissions returning as rainwater and leaching of metals from the soil.
Air pollution
Air pollutants generated by aluminium smelters include carbonyl sulfide, hydrogen fluoride, polycyclic compounds, lead, nickel, manganese, polychlorinated biphenyls, and mercury. Copper smelter emissions include arsenic, beryllium, cadmium, chromium, lead, manganese, and nickel. Lead smelters typically emit arsenic, antimony, cadmium and various lead compounds.
Wastewater
Wastewater pollutants discharged by iron and steel mills includes gasification products such as benzene, naphthalene, anthracene, cyanide, ammonia, phenols and cresols, together with a range of more complex organic compounds known collectively as polycyclic aromatic hydrocarbons (PAH). Treatment technologies include recycling of wastewater; settling basins, clarifiers and filtration systems for solids removal; oil skimmers and filtration; chemical precipitation and filtration for dissolved metals; carbon adsorption and biological oxidation for organic pollutants; and evaporation.
Pollutants generated by other types of smelters varies with the base metal ore. For example, aluminum smelters typically generate fluoride, benzo(a)pyrene, antimony and nickel, as well as aluminum. Copper smelters typically discharge cadmium, lead, zinc, arsenic and nickel, in addition to copper. Lead smelters may discharge antimony, asbestos, cadmium, copper and zinc, in addition to lead.
Health impacts
Labourers working in the smelting industry have reported respiratory illnesses inhibiting their ability to perform the physical tasks demanded by their jobs.
Regulations
In the United States, the Environmental Protection Agency has published pollution control regulations for smelters.
Air pollution standards under the Clean Air Act
Water pollution standards (effluent guidelines) under the Clean Water Act.
See also
Cast iron
Ellingham diagram, useful in predicting the conditions under which an ore reduces to its metal
Copper extraction techniques
Clinker
Cupellation
Lead smelting
Metallurgy
Metallurgy in pre-Columbian America
Pyrometallurgy
Wrought iron
Zinc smelting
References
Bibliography
Pleiner, R. (2000) Iron in Archaeology. The European Bloomery Smelters, Praha, Archeologický Ústav Av Cr.
Veldhuijzen, H.A. (2005) Technical Ceramics in Early Iron Smelting. The Role of Ceramics in the Early First Millennium Bc Iron Production at Tell Hammeh (Az-Zarqa), Jordan. In: Prudêncio, I.Dias, I. and Waerenborgh, J.C. (Eds.) Understanding People through Their Pottery; Proceedings of the 7th European Meeting on Ancient Ceramics (Emac '03). Lisboa, Instituto Português de Arqueologia (IPA).
Veldhuijzen, H.A. and Rehren, Th. (2006) Iron Smelting Slag Formation at Tell Hammeh (Az-Zarqa), Jordan. In: Pérez-Arantegui, J. (Ed.) Proceedings of the 34th International Symposium on Archaeometry, Zaragoza, 3–7 May 2004. Zaragoza, Institución «Fernando el Católico» (C.S.I.C.) Excma. Diputación de Zaragoza.
External links
Firing techniques
Metallurgical processes
de:Verhüttung | Smelting | Chemistry,Materials_science | 3,865 |
2,216,044 | https://en.wikipedia.org/wiki/Nuclear%20reaction%20analysis | Nuclear reaction analysis (NRA) is a nuclear method of nuclear spectroscopy in materials science to obtain concentration vs. depth distributions for certain target chemical elements in a solid thin film.
Mechanism of NRA
If irradiated with select projectile nuclei at kinetic energies Ekin, target solid thin-film chemical elements can undergo a nuclear reaction under resonance conditions for a sharply defined resonance energy. The reaction product is usually a nucleus in an excited state which immediately decays, emitting ionizing radiation.
To obtain depth information the initial kinetic energy of the projectile nucleus (which has to exceed the resonance energy) and its stopping power (energy loss per distance traveled) in the sample has to be known. To contribute to the nuclear reaction the projectile nuclei have to slow down in the sample to reach the resonance energy. Thus each initial kinetic energy corresponds to a depth in the sample where the reaction occurs (the higher the energy, the deeper the reaction).
NRA profiling of hydrogen
For example, a commonly used reaction to profile hydrogen with an energetic 15N ion beam is
15N + 1H → 12C + α + γ (4.43 MeV)
with a sharp resonance in the reaction cross section at 6.385 MeV of only 1.8 keV. Since the incident 15N ion loses energy along its trajectory in the material it must have an energy higher than the resonance energy to induce the nuclear reaction with hydrogen nuclei deeper in the target.
This reaction is usually written 1H(15N,αγ)12C. It is inelastic because the Q-value is not zero (in this case it is 4.965 MeV). Rutherford backscattering (RBS) reactions are elastic (Q = 0), and the interaction (scattering) cross-section σ given by the famous formula derived by Lord Rutherford in 1911. But non-Rutherford cross-sections (so-called EBS, elastic backscattering spectrometry) can also be resonant: for example, the 16O(α,α)16O reaction has a strong and very useful resonance at 3038.1 ± 1.3 keV.
In the 1H(15N,αγ)12C reaction (or indeed the 15N(p,αγ)12C inverse reaction), the energetic emitted γ ray is characteristic of the reaction and the number that are detected at any incident energy is proportional to the hydrogen concentration at the respective depth in the sample. Due to the narrow peak in the reaction cross section primarily ions of the resonance energy undergo a nuclear reaction. Thus, information on the hydrogen distribution can be straight forward obtained by varying the 15N incident beam energy.
Hydrogen is an element inaccessible to Rutherford backscattering spectrometry since nothing can backscatter from H (since all atoms are heavier than hydrogen!). But it is often analysed by elastic recoil detection.
Non-resonant NRA
NRA can also be used non-resonantly (of course, RBS is non-resonant). For example, deuterium can easily be profiled with a 3He beam without changing the incident energy by using the
3He + D = α + p + 18.353 MeV
reaction, usually written 2H(3He,p)α. The energy of the fast proton detected depends on the depth of the deuterium atom in the sample.
See also
Rutherford backscattering spectrometry (RBS)
References
External links
Details of many known reactions are hosted by the IAEA at http://www-nds.iaea.org/ibandl/.
The energy released in nuclear reactions (the "Q value") can easily be calculated (from E=mc2): see http://nucleardata.nuclear.lu.se/database/masses/.
NRA at JSI Microanalytical center in Ljubljana, Slovenia
Materials science
Surface science | Nuclear reaction analysis | Physics,Chemistry,Materials_science,Engineering | 808 |
31,667,930 | https://en.wikipedia.org/wiki/Expander%20code | In coding theory, expander codes form a class of error-correcting codes that are constructed from bipartite expander graphs.
Along with Justesen codes, expander codes are of particular interest since they have a constant positive rate, a constant positive relative distance, and a constant alphabet size.
In fact, the alphabet contains only two elements, so expander codes belong to the class of binary codes.
Furthermore, expander codes can be both encoded and decoded in time proportional to the block length of the code.
Expander codes
In coding theory, an expander code is a linear block code whose parity check matrix is the adjacency matrix of a bipartite expander graph. These codes have good relative distance , where and are properties of the expander graph as defined later, rate , and decodability (algorithms of running time exist).
Definition
Let be a -biregular graph between a set of nodes , called variables, and a set of nodes , called constraints.
Let be a function designed so that, for each constraint , the variables neighboring are .
Let be an error-correcting code of block length . The expander code is the code of block length whose codewords are the words such that, for , is a codeword of .
It has been shown that nontrivial lossless expander graphs exist. Moreover, we can explicitly construct them.
Rate
The rate of is its dimension divided by its block length. In this case, the parity check matrix has size , and hence has rate at least .
Distance
Suppose . Then the distance of a expander code is at least .
Proof
Note that we can consider every codeword in as a subset of vertices , by saying that vertex if and only if the th index of the codeword is a 1. Then is a codeword iff every vertex is adjacent to an even number of vertices in . (In order to be a codeword, , where is the parity check matrix. Then, each vertex in corresponds to each column of . Matrix multiplication over then gives the desired result.) So, if a vertex is adjacent to a single vertex in , we know immediately that is not a codeword. Let denote the neighbors in of , and denote those neighbors of which are unique, i.e., adjacent to a single vertex of .
Lemma 1
For every of size , .
Proof
Trivially, , since implies . follows since the degree of every vertex in is . By the expansion property of the graph, there must be a set of edges which go to distinct vertices. The remaining edges make at most neighbors not unique, so .
Corollary
Every sufficiently small has a unique neighbor. This follows since .
Lemma 2
Every subset with has a unique neighbor.
Proof
Lemma 1 proves the case , so suppose . Let such that . By Lemma 1, we know that . Then a vertex is in iff , and we know that , so by the first part of Lemma 1, we know . Since , , and hence is not empty.
Corollary
Note that if a has at least 1 unique neighbor, i.e. , then the corresponding word corresponding to cannot be a codeword, as it will not multiply to the all zeros vector by the parity check matrix. By the previous argument, . Since is linear, we conclude that has distance at least .
Encoding
The encoding time for an expander code is upper bounded by that of a general linear code - by matrix multiplication. A result due to Spielman shows that encoding is possible in time.
Decoding
Decoding of expander codes is possible in time when using the following algorithm.
Let be the vertex of that corresponds to the th index in the codewords of . Let be a received word, and . Let be , and be . Then consider the greedy algorithm:
Input: received word .
initialize y' to y
while there is a v in R adjacent to an odd number of vertices in V(y')
if there is an i such that o(i) > e(i)
flip entry i in y'
else
fail
Output: fail, or modified codeword .
Proof
We show first the correctness of the algorithm, and then examine its running time.
Correctness
We must show that the algorithm terminates with the correct codeword when the received codeword is within half the code's distance of the original codeword. Let the set of corrupt variables be , , and the set of unsatisfied (adjacent to an odd number of vertices) vertices in be . The following lemma will prove useful.
Lemma 3
If , then there is a with .
Proof
By Lemma 1, we know that . So an average vertex has at least unique neighbors (recall unique neighbors are unsatisfied and hence contribute to ), since , and thus there is a vertex with .
So, if we have not yet reached a codeword, then there will always be some vertex to flip. Next, we show that the number of errors can never increase beyond .
Lemma 4
If we start with , then we never reach at any point in the algorithm.
Proof
When we flip a vertex , and are interchanged, and since we had , this means the number of unsatisfied vertices on the right decreases by at least one after each flip. Since , the initial number of unsatisfied vertices is at most , by the graph's -regularity. If we reached a string with errors, then by Lemma 1, there would be at least unique neighbors, which means there would be at least unsatisfied vertices, a contradiction.
Lemmas 3 and 4 show us that if we start with (half the distance of ), then we will always find a vertex to flip. Each flip reduces the number of unsatisfied vertices in by at least 1, and hence the algorithm terminates in at most steps, and it terminates at some codeword, by Lemma 3. (Were it not at a codeword, there would be some vertex to flip). Lemma 4 shows us that we can never be farther than away from the correct codeword. Since the code has distance (since ), the codeword it terminates on must be the correct codeword, since the number of bit flips is less than half the distance (so we couldn't have traveled far enough to reach any other codeword).
Complexity
We now show that the algorithm can achieve linear time decoding. Let be constant, and be the maximum degree of any vertex in . Note that is also constant for known constructions.
Pre-processing: It takes time to compute whether each vertex in has an odd or even number of neighbors.
Pre-processing 2: We take time to compute a list of vertices in which have .
Each Iteration: We simply remove the first list element. To update the list of odd / even vertices in , we need only update entries, inserting / removing as necessary. We then update entries in the list of vertices in with more odd than even neighbors, inserting / removing as necessary. Thus each iteration takes time.
As argued above, the total number of iterations is at most .
This gives a total runtime of time, where and are constants.
See also
Expander graph
Low-density parity-check code
Linear time encoding and decoding of error-correcting codes
ABNNR and AEL codes
Notes
This article is based on Dr. Venkatesan Guruswami's course notes.
References
Error detection and correction
Coding theory
Capacity-approaching codes | Expander code | Mathematics,Engineering | 1,542 |
24,509,226 | https://en.wikipedia.org/wiki/Gymnopilus%20nitens | Gymnopilus nitens is a species of mushroom in the family Hymenogastraceae.
See also
List of Gymnopilus species
External links
Gymnopilus nitens at Index Fungorum
nitens
Fungi of North America
Fungus species | Gymnopilus nitens | Biology | 53 |
21,061,331 | https://en.wikipedia.org/wiki/Financial%20Modelers%27%20Manifesto | The Financial Modelers' Manifesto was a proposal for more responsibility in risk management and quantitative finance written by financial engineers Emanuel Derman and Paul Wilmott. The manifesto includes a Modelers' Hippocratic Oath. The structure of the Financial Modelers' Manifesto mirrors that of The Communist Manifesto of 1848.
The Manifesto and Oath were written in response to the Financial crisis of 2007–2010 with the collapse of subprime mortgages. A shortened version was published in Business Week in December 2008 with the complete version appearing shortly afterwards; the full text is available here.
Note that both authors had written extensively about the risks related to financial models for several years before the crisis; for example:
Emanuel Derman in 1996:
"There are always implicit assumptions behind a model and its solution method. But human beings have limited foresight and great imagination, so that, inevitably, a model will be used in ways its creator never intended. This is especially true in trading environments… but it’s also a matter of principle: you just cannot foresee everything. So, even a “correct” model, “correctly” solved, can lead to problems. The more complex the model, the greater this possibility."
Paul Wilmott in 2000:
"Unfortunately, as the mathematics of finance reaches higher levels so the level of common sense seems to drop. There have been some well publicised cases of large losses sustained by companies because of their lack of understanding of financial instruments…. It is clear that a major rethink is desperately required if the world is to avoid a mathematician-led market meltdown."
See also
Physics envy
Hippocratic Oath for scientists
References
External links
"Financial Models Must Be Clean and Simple" Business Week article
Financial Modelers' Manifesto - Full text
Mathematical finance
Manifestos
2008 documents
Financial models | Financial Modelers' Manifesto | Mathematics | 364 |
57,197,043 | https://en.wikipedia.org/wiki/Prime%20omega%20function | In number theory, the prime omega functions and count the number of prime factors of a natural number Thereby (little omega) counts each distinct prime factor, whereas the related function (big omega) counts the total number of prime factors of honoring their multiplicity (see arithmetic function). That is, if we have a prime factorization of of the form for distinct primes (), then the respective prime omega functions are given by and . These prime factor counting functions have many important number theoretic relations.
Properties and relations
The function is additive and is completely additive.
If divides at least once we count it only once, e.g. .
If divides times then we count the exponents, e.g. . As usual, means is the exact power of dividing .
If then is squarefree and related to the Möbius function by
If then is a prime power, and if then is a prime number.
It is known that the divisor function satisfies .
Like many arithmetic functions there is no explicit formula for or but there are approximations.
An asymptotic series for the average order of is given by
where is the Mertens constant and are the Stieltjes constants.
The function is related to divisor sums over the Möbius function and the divisor function including the next sums.
is the number of unitary divisors.
The characteristic function of the primes can be expressed by a convolution with the
Möbius function:
A partition-related exact identity for is given by
where is the partition function, is the Möbius function, and the triangular sequence is expanded by
in terms of the infinite q-Pochhammer symbol and the restricted partition functions which respectively denote the number of 's in all partitions of into an odd (even) number of distinct parts.
Continuation to the complex plane
A continuation of has been found, though it is not analytic everywhere. Note that the normalized function is used.
This is closely related to the following partition identity. Consider partitions of the form
where , , and are positive integers, and . The number of partitions is then given by .
Average order and summatory functions
An average order of both and is . When is prime a lower bound on the value of the function is . Similarly, if is primorial then the function is as large as
on average order. When is a power of 2, then
.
Asymptotics for the summatory functions over , , and
are respectively computed in Hardy and Wright as
where is the Mertens constant and the constant is defined by
The sum of number of unitary divisors:
Other sums relating the two variants of the prime omega functions include
and
Example I: A modified summatory function
In this example we suggest a variant of the summatory functions estimated in the above results for sufficiently large . We then prove an asymptotic formula for the growth of this modified summatory function derived from the asymptotic estimate of provided in the formulas in the main subsection of this article above.
To be completely precise, let the odd-indexed summatory function be defined as
where denotes Iverson bracket. Then we have that
The proof of this result follows by first observing that
and then applying the asymptotic result from Hardy and Wright for the summatory function over , denoted by , in the following form:
Example II: Summatory functions for so-termed factorial moments of ω(n)
The computations expanded in Chapter 22.11 of Hardy and Wright provide asymptotic estimates for the summatory function
by estimating the product of these two component omega functions as
We can similarly calculate asymptotic formulas more generally for the related summatory functions over so-termed factorial moments of the function .
Dirichlet series
A known Dirichlet series involving and the Riemann zeta function is given by
We can also see that
The function is completely additive, where is strongly additive (additive). Now we can prove a short lemma in the following form which implies exact formulas for the expansions of the Dirichlet series over both and :
Lemma. Suppose that is a strongly additive arithmetic function defined such that its values at prime powers is given by , i.e., for distinct primes and exponents . The Dirichlet series of is expanded by
Proof. We can see that
This implies that
wherever the corresponding series and products are convergent. In the last equation, we have used the Euler product representation of the Riemann zeta function.
The lemma implies that for ,
where is the prime zeta function, where is the -th harmonic number and is the identity for the Dirichlet convolution, .
The distribution of the difference of prime omega functions
The distribution of the distinct integer values of the differences is regular in comparison with the semi-random properties of the component functions. For , define
These cardinalities have a corresponding sequence of limiting densities such that for
These densities are generated by the prime products
With the absolute constant ,
the densities satisfy
Compare to the definition of the prime products defined in the last section of in relation to the Erdős–Kac theorem.
See also
Additive function
Arithmetic function
Erdős–Kac theorem
Omega function (disambiguation)
Prime number
Square-free integer
Notes
References
External links
OEIS Wiki for related sequence numbers and tables
OEIS Wiki on Prime Factors
Number theory
Prime numbers
Additive functions
Integer sequences | Prime omega function | Mathematics | 1,115 |
55,013,035 | https://en.wikipedia.org/wiki/French%20Crystallographic%20Association | The French Crystallographic Association (L’Association française de cristallographie or AFC) brings together physicists, chemists and biologists that use crystals and crystallography in their research or develop new crystallographic methods. Originally part of the French Society of Mineralogy, the AFC was founded in 1953 by Hubert Curien and André Guinier.
Today, its main goals are to promote dissemination of knowledge and exchange between French speaking crystallographers from all fields, and in particular to organize or support specialized or interdisciplinary workshops and conferences, educational actions and training courses in the area of crystallography. During the biannual AFC conferences, the AFC awards three PhD prizes in each of its research areas: Physics, Chemistry and Biology.
Claude Sauter, scientist at the Institut de Biologie Moléculaire et Cellulaire in Strasbourg is the President of the AFC from January 1st, 2022.
Presidents of the AFC
André Guinier
Robert Gay
Jean Wyart
1962 Erwin Félix Lewy-Bertaut
1965 Hubert Curien
1970-1972 André Authier
1972-1973 Stanislas Goldstaub
1981-1983 Jean Meinnel
1984-1987 Jean-François Petroff
1987-1990 Michel Hospital
1990-1993 Massimo Marezio
1994-1997 Roger Fourme
1997-2002 Claude Lecomte
2003-2007 Jean-Louis Hodeau
2008-2010 Jean-Claude Daran
2011-2013 Jacqueline Cherfils
2013-2016 René Guinebretière
2017-2021 Philippe Guionneau
2022-2025 Claude Sauter
See also
International Union of Crystallography
European Crystallographic Association
References
External links
Website of the French Crystallographic Association
Crystallography organizations
Scientific organizations established in 1953
Scientific organizations based in France
1953 establishments in France
Chemistry societies | French Crystallographic Association | Chemistry,Materials_science | 359 |
28,306,565 | https://en.wikipedia.org/wiki/Gilbert%20Morgan%20Smith%20Medal | The Gilbert Morgan Smith Medal is awarded by the U.S. National Academy of Sciences "in recognition of excellence in published research on marine or freshwater algae." It has been awarded every three years since 1979.
List of Gilbert Morgan Smith Medal winners
Source: NAS
Mark E. Hay (2018)
For developing algae as the major model for marine chemical ecology, and for elucidating how chemical cues and signals from algae structure marine and aquatic populations, communities, and ecosystems.
Takao Kondo (2015)
For demonstrating the occurrence of circadian clocks in prokaryotes, leading through genetic dissection to the discovery of the central bacterial clock genes, kaiABC, and to a new way of thinking about algal ecology.
John B. Waterbury (2012)
For the discovery and characterization of planktonic marine cyanobacteria, and viruses that infect them, setting in motion a paradigm shift in our understanding of ocean productivity, ecology, and biogeochemical cycles.
Arthur R. Grossman (2009)
For pioneering creative and comprehensive research on algae and cyanobacteria, elucidating molecular mechanisms by which they adapt to changes in light color and to nutrient stress.
Sabeeha Merchant (2006)
For her pioneering discoveries in the assembly of metalloenzymes and the regulated biogenesis of major complexes of the photosynthetic apparatus in green algae.
Sarah P. Gibbs (2003)
For her revolutionary concepts and evidence that constitute the foundation for the current theory of chloroplast evolution and the phylogenetic relationships of algae and plants.
Shirley W. Jeffrey (2000)
For her discovery and characterization of major algal pigments, their quantitative application in oceanography, and for providing phytoplankton cultures for international research.
Isabella A. Abbott (1997)
For her comprehensive investigations of the biogeography and systematics of marine algae in the eastern and central Pacific, with emphasis on Rhodophyta, the red algae.
Elisabeth Gantt (1994)
For her pioneering work in elucidating the supramolecular structure of the light-harvesting complexes and energy transfer in the photosynthetic apparatus of red and blue-green algae.
Jean-David Rochaix (1991)
For his elegant, inventive studies in Chlamydomonas using genetics along with cell and molecular biology to explain molecular mechanisms of chloroplast biogenesis, photosynthesis, and nuclear-chloroplast interactions.
Ruth Sager (1988)
For her key role in the developing our understanding of genetic systems in organelles though her studies of chloroplast inheritance in the green alga Chlamydomonas
Richard C. Starr (1985)
For his important work, which explained the sexuality of desmids and green algae. This was the first time the details of meiosis had been set forth for these groups.
Luigi Provasoli (1982)
For his excellence in phycology, especially for his work on the culture and nutrition of algae, and the influence of bacteria and organic substances on the morphology of larger algae.
William R. Taylor (1979)
For his outstanding contributions to the knowledge of the marine algae of Florida, the Caribbean Sea, the Northwestern Atlantic, and the tropical Pacific Oceans.
See also
Gilbert Morgan Smith
List of biology awards
Prizes named after people
References
Awards established in 1979
Biology awards
Awards of the United States National Academy of Sciences | Gilbert Morgan Smith Medal | Technology | 697 |
29,690,231 | https://en.wikipedia.org/wiki/Hybtonite | Hybtonite is trademark of Amroy Europe Oy for carbon nanoepoxy resins. It is a family of composite resins reinforced with carbon nanotubes (CNTs).
The material and the manufacturing method were originally developed in the Nanoscience Center of the University of Jyväskylä during the years 2002 to 2004.
Ultrasound is used to disperse the nanotubes and to create radicals at the ends of CNT molecules.
CNTs can then chemically react with epoxy resin or other material forming strong covalent bonds. This results in a more durable hybrid composite structure that is between 20% and 30% stronger (with only 0.5% CNT contents) than a conventional reinforced plastic.
The manufacturing process allows controlling the material properties such as electrical conductivity, thermal conductivity and viscosity. Different forms of hybtonite are available for different purposes such as laminating (glass fiber, carbon fiber), epoxy paints and glues.
Applications
The first application areas for hybtonite have been in field of wind turbines, marine applications and sports gear.
Montreal Nitro ice hockey stick was the first commercial product using hybtonite.
Cross-country skis and roller skis by Peltonen Sports
Baseball bats by Karhu Sports
Hunting arrows by Easton
Surfboards by Entropy Surfboards
Eagle Windpower manufactures small size (2 kW to 100 kW) wind turbines using hybtonite as material for the blades.
Large wind turbines manufactured by Evergreen (China), LM Glassfiber (Denmark) and CompoTech (Czech Republic)
Marine paints / AMC nano coating.
Awards
In January 2006, Montreal Hybtonite hockey stick "Nitro" was voted number one Nano product in the world at Nanotech 2006 trade show in Tokyo, Japan.
In December 2009, Amroy received Frost & Sullivan European Technology Innovation Award for its work on hybtonite.
References
Composite materials
Nanomaterials
Finnish inventions
Synthetic resins | Hybtonite | Physics,Chemistry,Materials_science | 413 |
37,665,404 | https://en.wikipedia.org/wiki/Phi1%20Lupi | {{DISPLAYTITLE:Phi1 Lupi}}
Phi1 Lupi is a solitary star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 3.58. Based upon an annual parallax shift of 11.86 mas as seen from Earth, it is located around 275 light years from the Sun. The star is drifting closer with a radial velocity of −29 km/s. It has an absolute magnitude of −1.55.
This is an evolved K-type giant star with a stellar classification of K5 III, which means it has used up its core hydrogen and has expanded. At present it has 40 times the radius of the Sun. It is a variable star of unknown type, with an amplitude of 0.008 in visual magnitude and a period of 4.82 days. The star is radiating 711 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,894 K.
References
K-type giants
Suspected variables
Zeta Herculis Moving Group
Lupus (constellation)
Lupi, Phi1
136422
075177
5705
Durchmusterung objects | Phi1 Lupi | Astronomy | 244 |
1,170,160 | https://en.wikipedia.org/wiki/Chirality%20%28mathematics%29 | In geometry, a figure is chiral (and said to have chirality) if it is not identical to its mirror image, or, more precisely, if it cannot be mapped to its mirror image by rotations and translations alone. An object that is not chiral is said to be achiral.
A chiral object and its mirror image are said to be enantiomorphs. The word chirality is derived from the Greek (cheir), the hand, the most familiar chiral object; the word enantiomorph stems from the Greek (enantios) 'opposite' + (morphe) 'form'.
Examples
Some chiral three-dimensional objects, such as the helix, can be assigned a right or left handedness, according to the right-hand rule.
Many other familiar objects exhibit the same chiral symmetry of the human body, such as gloves and shoes. Right shoes differ from left shoes only by being mirror images of each other. In contrast thin gloves may not be considered chiral if you can wear them inside-out.
The J-, L-, S- and Z-shaped tetrominoes of the popular video game Tetris also exhibit chirality, but only in a two-dimensional space. Individually they contain no mirror symmetry in the plane.
Chirality and symmetry group
A figure is achiral if and only if its symmetry group contains at least one orientation-reversing isometry. (In Euclidean geometry any isometry can be written as with an orthogonal matrix and a vector . The determinant of is either 1 or −1 then. If it is −1 the isometry is orientation-reversing, otherwise it is orientation-preserving.
A general definition of chirality based on group theory exists. It does not refer to any orientation concept: an isometry is direct if and only if it is a product of squares of isometries, and if not, it is an indirect isometry. The resulting chirality definition works in spacetime.
Chirality in two dimensions
In two dimensions, every figure which possesses an axis of symmetry is achiral, and it can be shown that every bounded achiral figure must have an axis of symmetry. (An axis of symmetry of a figure is a line , such that is invariant under the mapping , when is chosen to be the -axis of the coordinate system.) For that reason, a triangle is achiral if it is equilateral or isosceles, and is chiral if it is scalene.
Consider the following pattern:
This figure is chiral, as it is not identical to its mirror image:
But if one prolongs the pattern in both directions to infinity, one receives an (unbounded) achiral figure which has no axis of symmetry. Its symmetry group is a frieze group generated by a single glide reflection.
Chirality in three dimensions
In three dimensions, every figure that possesses a mirror plane of symmetry S1, an inversion center of symmetry S2, or a higher improper rotation (rotoreflection) Sn axis of symmetry is achiral. (A plane of symmetry of a figure is a plane , such that is invariant under the mapping , when is chosen to be the --plane of the coordinate system. A center of symmetry of a figure is a point , such that is invariant under the mapping , when is chosen to be the origin of the coordinate system.) Note, however, that there are achiral figures lacking both plane and center of symmetry. An example is the figure
which is invariant under the orientation reversing isometry and thus achiral, but it has neither plane nor center of symmetry. The figure
also is achiral as the origin is a center of symmetry, but it lacks a plane of symmetry.
Achiral figures can have a center axis.
Knot theory
A knot is called achiral if it can be continuously deformed into its mirror image, otherwise it is called a chiral knot. For example, the unknot and the figure-eight knot are achiral, whereas the trefoil knot is chiral.
See also
Chiral polytope
Chirality (physics)
Parity (physics)
Chirality (chemistry)
Asymmetry
Skewness
Vertex algebra
References
Further reading
External links
Symmetry, Chirality, Symmetry Measures and Chirality Measures: General Definitions
Chiral Polyhedra by Eric W. Weisstein, The Wolfram Demonstrations Project.
Chiral manifold at the Manifold Atlas.
Knot theory
Polyhedra
Chirality
Topology | Chirality (mathematics) | Physics,Chemistry,Mathematics,Biology | 949 |
3,892,745 | https://en.wikipedia.org/wiki/Dissolved%20air%20flotation | Dissolved air flotation (DAF) is a water treatment process that clarifies wastewaters (or other waters) by the removal of suspended matter such as oil or solids. The removal is achieved by dissolving air in the water or wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank basin. The released air forms tiny bubbles which adhere to the suspended matter, causing the suspended matter to float to the surface of the water where it may then be removed by a skimming device.
Dissolved air flotation is very widely used in treating the industrial wastewater effluents from oil refineries, petrochemical and chemical plants, natural gas processing plants, paper mills, general water treatment and similar industrial facilities. A very similar process known as induced gas flotation is also used for wastewater treatment. Froth flotation is commonly used in the processing of mineral ores.
In the oil industry, dissolved gas flotation (DGF) units do not use air as the flotation medium due to the explosion risk. Nitrogen gas is used instead to create the bubbles.
Process description
The feed water to the DAF float tank is often (but not always) dosed with a coagulant (such as ferric chloride or aluminum sulfate) to coagulate the colloidal particles and/or a flocculant to conglomerate the particles into bigger clusters.
A portion of the clarified effluent water leaving the DAF tank is pumped into a small pressure vessel (called the air drum) into which compressed air is also introduced. This results in saturating the pressurized effluent water with air. The air-saturated water stream is recycled to the front of the float tank and flows through a pressure reduction valve just as it enters the front of the float tank, which results in the air being released in the form of tiny bubbles. Bubbles form at nucleation sites on the surface of the suspended particles, adhering to the particles. As more bubbles form, the lift from the bubbles eventually overcomes the force of gravity. This causes the suspended matter to float to the surface where it forms a froth layer which is then removed by a skimmer. The froth-free water exits the float tank as the clarified effluent from the DAF unit.
Some DAF unit designs utilize parallel plate packing material (e.g. lamellas) to provide more separation surface and therefore to enhance the separation efficiency of the unit.
DAF systems can be categorized as circular (more efficient) and rectangular (more residence time). The former type requires just 3 minutes. The rectangular type requires 20 to 30 minutes. One of the bigger advantages of the circular type is its spiral scoop.
Drinking water treatment
Drinking water supplies that are particularly vulnerable to unicellular algal blooms, and supplies with low turbidity and high colour often employ DAF. After coagulation and flocculation processes, water flows to DAF tanks where air diffusers on the tank bottom create fine bubbles that attach to floc resulting in a floating mass of concentrated floc. The floating floc blanket is removed from the surface and clarified water is withdrawn from the bottom of the DAF tank.
See also
API oil-water separator
Flotation process
Industrial wastewater treatment
Industrial water treatment
List of waste-water treatment technologies
Microflotation
References
External links
Treatment and Disposal of Ship-Generated Solid and Liquid Wastes (REMPEC Regional Marine Pollution Emergency Response Centre for the Mediterranean Sea, Project MED.B4.4100.97.0415.8, April 2004)
Dissolved Air Flotation (DAF) Knowledge Encyclopedia
Flotation processes
Water treatment
Waste treatment technology | Dissolved air flotation | Chemistry,Engineering,Environmental_science | 765 |
61,657,506 | https://en.wikipedia.org/wiki/Hydnellum%20scabrosum | Hydnellum scabrosum, also called bitter tooth or bitter hedgehog, is a species of tooth fungus in the family Bankeraceae.
Taxonomy
It was originally described by Swedish botanist Elias Fries as Hydnum scabrosum in 1836. Finnish mycologist Petter Karsten moved it to the genus Sarcodon in 1881. This species remained as Sarcodon scabrosus until 2019, when a molecular analysis using nuclear DNA showed that this and 11 other species lay genetically within the genus Hydnellum, a genus of which harder woody flesh had previously been considered a distinguishing feature from soft-fleshed Sarcodon.
Within the genus it is most closely related to H. fennicum.
Description
The fruit body (mushroom) has a convex to flattened brownish cap up to across that is covered with brown scales. It can be tinged with pink at the margins and darken with age. The mushroom has yellow-brown spines under the cap that are long and in diameter. They are decurrent to the stem. The pinkish brown stem is high and wide, and has a narrower base that is a characteristic greyish green colour. The flesh is whitish and has a bitter taste, rendering the mushroom inedible. The flesh smells farinaceous or like watermelon when cut.
Distribution and habitat
It is found in association with hardwood forests across Eurasia to Japan, as well as North America.
Biochemistry
The species has been investigated for bioactive agents. In 2004, Tsunashi Kamo and colleagues isolated diterpenoids with experimental anti-inflammatory activity. Other diterpenoids were shown to stimulate nerve growth factor (NGF). Yet another agent, an alpha-pyrone, was shown to inhibit lettuce seedling growth.
Similar species
Sarcodon imbricatus is similar, but the scales do not become as prominent in age. Other similar species include S. fennicus, S. rimosus, S. subincarnatus, and S. underwoodii.
References
scabrosum
Fungi of Europe
Taxa named by Elias Magnus Fries
Fungi described in 1836
Fungus species | Hydnellum scabrosum | Biology | 435 |
1,956,306 | https://en.wikipedia.org/wiki/Product%20order | In mathematics, given a partial order and on a set and , respectively, the product order (also called the coordinatewise order or componentwise order) is a partial ordering on the Cartesian product Given two pairs and in declare that if and
Another possible ordering on is the lexicographical order. It is a total ordering if both and are totally ordered. However the product order of two total orders is not in general total; for example, the pairs and are incomparable in the product order of the ordering with itself. The lexicographic combination of two total orders is a linear extension of their product order, and thus the product order is a subrelation of the lexicographic order.
The Cartesian product with the product order is the categorical product in the category of partially ordered sets with monotone functions.
The product order generalizes to arbitrary (possibly infinitary) Cartesian products.
Suppose is a set and for every is a preordered set.
Then the on is defined by declaring for any and in that
if and only if for every
If every is a partial order then so is the product preorder.
Furthermore, given a set the product order over the Cartesian product can be identified with the inclusion ordering of subsets of
The notion applies equally well to preorders. The product order is also the categorical product in a number of richer categories, including lattices and Boolean algebras.
See also
Direct product of binary relations
Examples of partial orders
Star product, a different way of combining partial orders
Orders on the Cartesian product of totally ordered sets
Ordinal sum of partial orders
References
Order theory | Product order | Mathematics | 333 |
24,507,887 | https://en.wikipedia.org/wiki/Gymnopilus%20sordidostipes | Gymnopilus sordidostipes is a species of mushroom-forming fungus in the family Hymenogastraceae.
Description
The cap is in diameter.
Distribution and habitat
Gymnopilus sordidostipes has been found growing in clusters on sawdust, in Oregon during November.
See also
List of Gymnopilus species
References
sordidostipes
Fungi of North America
Fungi described in 1969
Taxa named by Lexemuel Ray Hesler
Fungus species | Gymnopilus sordidostipes | Biology | 97 |
21,210 | https://en.wikipedia.org/wiki/Niels%20Bohr | Niels Henrik David Bohr (7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research.
Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philosophy.
Bohr founded the Institute of Theoretical Physics at the University of Copenhagen, now known as the Niels Bohr Institute, which opened in 1920. Bohr mentored and collaborated with physicists including Hans Kramers, Oskar Klein, George de Hevesy, and Werner Heisenberg. He predicted the properties of a new zirconium-like element, which was named hafnium, after the Latin name for Copenhagen, where it was discovered. Later, the synthetic element bohrium was named after him because of his groundbreaking work on the structure of atoms.
During the 1930s, Bohr helped refugees from Nazism. After Denmark was occupied by the Germans, he met with Heisenberg, who had become the head of the German nuclear weapon project. In September 1943 word reached Bohr that he was about to be arrested by the Germans, so he fled to Sweden. From there, he was flown to Britain, where he joined the British Tube Alloys nuclear weapons project, and was part of the British mission to the Manhattan Project. After the war, Bohr called for international cooperation on nuclear energy. He was involved with the establishment of CERN and the Research Establishment Risø of the Danish Atomic Energy Commission and became the first chairman of the Nordic Institute for Theoretical Physics in 1957.
Early life
Niels Henrik David Bohr was born in Copenhagen, Denmark, on 7 October 1885, the second of three children of Christian Bohr, a professor of physiology at the University of Copenhagen, and his wife Ellen Adler, who came from a wealthy Jewish banking family. He had an elder sister, Jenny, and a younger brother Harald. Jenny became a teacher, while Harald became a mathematician and footballer who played for the Danish national team at the 1908 Summer Olympics in London. Niels was a passionate footballer as well, and the two brothers played several matches for the Copenhagen-based Akademisk Boldklub (Academic Football Club), with Niels as goalkeeper.
Bohr was educated at Gammelholm Latin School, starting when he was seven. In 1903, Bohr enrolled as an undergraduate at Copenhagen University. His major was physics, which he studied under Professor Christian Christiansen, the university's only professor of physics at that time. He also studied astronomy and mathematics under Professor Thorvald Thiele, and philosophy under Professor Harald Høffding, a friend of his father.
In 1905 a gold medal competition was sponsored by the Royal Danish Academy of Sciences and Letters to investigate a method for measuring the surface tension of liquids that had been proposed by Lord Rayleigh in 1879. This involved measuring the frequency of oscillation of the radius of a water jet. Bohr conducted a series of experiments using his father's laboratory in the university; the university itself had no physics laboratory. To complete his experiments, he had to make his own glassware, creating test tubes with the required elliptical cross-sections. He went beyond the original task, incorporating improvements into both Rayleigh's theory and his method, by taking into account the viscosity of the water, and by working with finite amplitudes instead of just infinitesimal ones. His essay, which he submitted at the last minute, won the prize. He later submitted an improved version of the paper to the Royal Society in London for publication in the Philosophical Transactions of the Royal Society.
Harald became the first of the two Bohr brothers to earn a master's degree, which he earned for mathematics in April 1909. Niels took another nine months to earn his on the electron theory of metals, a topic assigned by his supervisor, Christiansen. Bohr subsequently elaborated his master's thesis into his much-larger Doctor of Philosophy thesis. He surveyed the literature on the subject, settling on a model postulated by Paul Drude and elaborated by Hendrik Lorentz, in which the electrons in a metal are considered to behave like a gas. Bohr extended Lorentz's model, but was still unable to account for phenomena like the Hall effect, and concluded that electron theory could not fully explain the magnetic properties of metals. The thesis was accepted in April 1911, and Bohr conducted his formal defence on 13 May. Harald had received his doctorate the previous year. Bohr's thesis was groundbreaking, but attracted little interest outside Scandinavia because it was written in Danish, a Copenhagen University requirement at the time. In 1921, the Dutch physicist Hendrika Johanna van Leeuwen would independently derive a theorem in Bohr's thesis that is today known as the Bohr–Van Leeuwen theorem.
In 1910, Bohr met Margrethe Nørlund, the sister of the mathematician Niels Erik Nørlund. Bohr resigned his membership in the Church of Denmark on 16 April 1912, and he and Margrethe were married in a civil ceremony at the town hall in Slagelse on 1 August. Years later, his brother Harald similarly left the church before getting married. Bohr and Margrethe had six sons. The oldest, Christian, died in a boating accident in 1934, and another, Harald, was severely mentally disabled. He was placed in an institution away from his family's home at the age of four and died from childhood meningitis six years later. Aage Bohr became a successful physicist, and in 1975 was awarded the Nobel Prize in physics, like his father. A son of Aage, Vilhelm A. Bohr, is a scientist affiliated with the University of Copenhagen and the National Institute on Aging in the U.S. became a physician; , a chemical engineer; and Ernest, a lawyer. Like his uncle Harald, Ernest Bohr became an Olympic athlete, playing field hockey for Denmark at the 1948 Summer Olympics in London.
Physics
Bohr model
In September 1911, Bohr, supported by a fellowship from the Carlsberg Foundation, travelled to England, where most of the theoretical work on the structure of atoms and molecules was being done. He met J. J. Thomson of the Cavendish Laboratory and Trinity College, Cambridge. He attended lectures on electromagnetism given by James Jeans and Joseph Larmor, and did some research on cathode rays, but failed to impress Thomson. He had more success with younger physicists like the Australian William Lawrence Bragg, and New Zealand's Ernest Rutherford, whose 1911 small central nucleus Rutherford model of the atom had challenged Thomson's 1904 plum pudding model. Bohr received an invitation from Rutherford to conduct post-doctoral work at Victoria University of Manchester, where Bohr met George de Hevesy and Charles Galton Darwin (whom Bohr referred to as "the grandson of the real Darwin").
Bohr returned to Denmark in July 1912 for his wedding, and travelled around England and Scotland on his honeymoon. On his return, he became a privatdocent at the University of Copenhagen, giving lectures on thermodynamics. Martin Knudsen put Bohr's name forward for a docent, which was approved in July 1913, and Bohr then began teaching medical students. His three papers, which later became famous as "the trilogy", were published in Philosophical Magazine in July, September and November of that year. He adapted Rutherford's nuclear structure to Max Planck's quantum theory and so created his Bohr model of the atom.
Planetary models of atoms were not new, but Bohr's treatment was. Taking the 1912 paper by Darwin on the role of electrons in the interaction of alpha particles with a nucleus as his starting point, he advanced the theory of electrons travelling in orbits of quantised "stationary states" around the atom's nucleus in order to stabilise the atom, but it wasn't until his 1921 paper that he showed that the chemical properties of each element were largely determined by the number of electrons in the outer orbits of its atoms. He introduced the idea that an electron could drop from a higher-energy orbit to a lower one, in the process emitting a quantum of discrete energy. This became a basis for what is now known as the old quantum theory.
In 1885, Johann Balmer had come up with his Balmer series to describe the visible spectral lines of a hydrogen atom:
where λ is the wavelength of the absorbed or emitted light and RH is the Rydberg constant. Balmer's formula was corroborated by the discovery of additional spectral lines, but for thirty years, no one could explain why it worked. In the first paper of his trilogy, Bohr was able to derive it from his model:
where me is the electron's mass, e is its charge, h is the Planck constant and Z is the atom's atomic number (1 for hydrogen).
The model's first hurdle was the Pickering series, lines that did not fit Balmer's formula. When challenged on this by Alfred Fowler, Bohr replied that they were caused by ionised helium, helium atoms with only one electron. The Bohr model was found to work for such ions. Many older physicists, like Thomson, Rayleigh and Hendrik Lorentz, did not like the trilogy, but the younger generation, including Rutherford, David Hilbert, Albert Einstein, Enrico Fermi, Max Born and Arnold Sommerfeld saw it as a breakthrough. The trilogy's acceptance was entirely due to its ability to explain phenomena that stymied other models, and to predict results that were subsequently verified by experiments. Today, the Bohr model of the atom has been superseded, but is still the best known model of the atom, as it often appears in high school physics and chemistry texts.
Bohr did not enjoy teaching medical students. He later admitted that he was not a good lecturer, because he needed a balance between clarity and truth, between "Klarheit und Wahrheit". He decided to return to Manchester, where Rutherford had offered him a job as a reader in place of Darwin, whose tenure had expired. Bohr accepted. He took a leave of absence from the University of Copenhagen, which he started by taking a holiday in Tyrol with his brother Harald and aunt Hanna Adler. There, he visited the University of Göttingen and the Ludwig Maximilian University of Munich, where he met Sommerfeld and conducted seminars on the trilogy. The First World War broke out while they were in Tyrol, greatly complicating the trip back to Denmark and Bohr's subsequent voyage with Margrethe to England, where he arrived in October 1914. They stayed until July 1916, by which time he had been appointed to the Chair of Theoretical Physics at the University of Copenhagen, a position created especially for him. His docentship was abolished at the same time, so he still had to teach physics to medical students. New professors were formally introduced to King Christian X, who expressed his delight at meeting such a famous football player.
Institute of Physics
In April 1917, Bohr began a campaign to establish an Institute of Theoretical Physics. He gained the support of the Danish government and the Carlsberg Foundation, and sizeable contributions were also made by industry and private donors, many of them Jewish. Legislation establishing the institute was passed in November 1918. Now known as the Niels Bohr Institute, it opened on 3 March 1921, with Bohr as its director. His family moved into an apartment on the first floor. Bohr's institute served as a focal point for researchers into quantum mechanics and related subjects in the 1920s and 1930s, when most of the world's best-known theoretical physicists spent some time in his company. Early arrivals included Hans Kramers from the Netherlands, Oskar Klein from Sweden, George de Hevesy from Hungary, Wojciech Rubinowicz from Poland, and Svein Rosseland from Norway. Bohr became widely appreciated as their congenial host and eminent colleague. Klein and Rosseland produced the institute's first publication even before it opened.
The Bohr model worked well for hydrogen and ionized single-electron helium, which impressed Einstein but could not explain more complex elements. By 1919, Bohr was moving away from the idea that electrons orbited the nucleus and developed heuristics to describe them. The rare-earth elements posed a particular classification problem for chemists because they were so chemically similar. An important development came in 1924 with Wolfgang Pauli's discovery of the Pauli exclusion principle, which put Bohr's models on a firm theoretical footing. Bohr was then able to declare that the as-yet-undiscovered element 72 was not a rare-earth element but an element with chemical properties similar to those of zirconium. (Elements had been predicted and discovered since 1871 by chemical properties), and Bohr was immediately challenged by the French chemist Georges Urbain, who claimed to have discovered a rare-earth element 72, which he called "celtium". At the Institute in Copenhagen, Dirk Coster and George de Hevesy took up the challenge of proving Bohr right and Urbain wrong. Starting with a clear idea of the chemical properties of the unknown element greatly simplified the search process. They went through samples from Copenhagen's Museum of Mineralogy looking for a zirconium-like element and soon found it. The element, which they named hafnium (hafnia being the Latin name for Copenhagen), turned out to be more common than gold.
In 1922, Bohr was awarded the Nobel Prize in Physics "for his services in the investigation of the structure of atoms and of the radiation emanating from them". The award thus recognised both the trilogy and his early leading work in the emerging field of quantum mechanics. For his Nobel lecture, Bohr gave his audience a comprehensive survey of what was then known about the structure of the atom, including the correspondence principle, which he had formulated. This states that the behaviour of systems described by quantum theory reproduces classical physics in the limit of large quantum numbers.
The discovery of Compton scattering by Arthur Holly Compton in 1923 convinced most physicists that light was composed of photons and that energy and momentum were conserved in collisions between electrons and photons. In 1924, Bohr, Kramers, and John C. Slater, an American physicist working at the Institute in Copenhagen, proposed the Bohr–Kramers–Slater theory (BKS). It was more of a program than a full physical theory, as the ideas it developed were not worked out quantitatively. The BKS theory became the final attempt at understanding the interaction of matter and electromagnetic radiation on the basis of the old quantum theory, in which quantum phenomena were treated by imposing quantum restrictions on a classical wave description of the electromagnetic field.
Modelling atomic behaviour under incident electromagnetic radiation using "virtual oscillators" at the absorption and emission frequencies, rather than the (different) apparent frequencies of the Bohr orbits, led Max Born, Werner Heisenberg and Kramers to explore different mathematical models. They led to the development of matrix mechanics, the first form of modern quantum mechanics. The BKS theory also generated discussion of, and renewed attention to, difficulties in the foundations of the old quantum theory. The most provocative element of BKS – that momentum and energy would not necessarily be conserved in each interaction, but only statistically – was soon shown to be in conflict with experiments conducted by Walther Bothe and Hans Geiger. In light of these results, Bohr informed Darwin that "there is nothing else to do than to give our revolutionary efforts as honourable a funeral as possible".
Quantum mechanics
The introduction of spin by George Uhlenbeck and Samuel Goudsmit in November 1925 was a milestone. The next month, Bohr travelled to Leiden to attend celebrations of the 50th anniversary of Hendrick Lorentz receiving his doctorate. When his train stopped in Hamburg, he was met by Wolfgang Pauli and Otto Stern, who asked for his opinion of the spin theory. Bohr pointed out that he had concerns about the interaction between electrons and magnetic fields. When he arrived in Leiden, Paul Ehrenfest and Albert Einstein informed Bohr that Einstein had resolved this problem using relativity. Bohr then had Uhlenbeck and Goudsmit incorporate this into their paper. Thus, when he met Werner Heisenberg and Pascual Jordan in Göttingen on the way back, he had become, in his own words, "a prophet of the electron magnet gospel".
Heisenberg first came to Copenhagen in 1924, then returned to Göttingen in June 1925, shortly thereafter developing the mathematical foundations of quantum mechanics. When he showed his results to Max Born in Göttingen, Born realised that they could best be expressed using matrices. This work attracted the attention of the British physicist Paul Dirac, who came to Copenhagen for six months in September 1926. Austrian physicist Erwin Schrödinger also visited in 1926. His attempt at explaining quantum physics in classical terms using wave mechanics impressed Bohr, who believed it contributed "so much to mathematical clarity and simplicity that it represents a gigantic advance over all previous forms of quantum mechanics".
When Kramers left the institute in 1926 to take up a chair as professor of theoretical physics at the Utrecht University, Bohr arranged for Heisenberg to return and take Kramers's place as a lektor at the University of Copenhagen. Heisenberg worked in Copenhagen as a university lecturer and assistant to Bohr from 1926 to 1927.
Bohr became convinced that light behaved like both waves and particles and, in 1927, experiments confirmed the de Broglie hypothesis that matter (like electrons) also behaved like waves. He conceived the philosophical principle of complementarity: that items could have apparently mutually exclusive properties, such as being a wave or a stream of particles, depending on the experimental framework. He felt that it was not fully understood by professional philosophers.
In February 1927, Heisenberg developed the first version of the uncertainty principle, presenting it using a thought experiment where an electron was observed through a gamma-ray microscope. Bohr was dissatisfied with Heisenberg's argument, since it required only that a measurement disturb properties that already existed, rather than the more radical idea that the electron's properties could not be discussed at all apart from the context they were measured in. In a paper presented at the Volta Conference at Como in September 1927, Bohr emphasised that Heisenberg's uncertainty relations could be derived from classical considerations about the resolving power of optical instruments. Understanding the true meaning of complementarity would, Bohr believed, require "closer investigation". Einstein preferred the determinism of classical physics over the probabilistic new quantum physics to which he himself had contributed. Philosophical issues that arose from the novel aspects of quantum mechanics became widely celebrated subjects of discussion. Einstein and Bohr had good-natured arguments over such issues throughout their lives.
In 1914 Carl Jacobsen, the heir to Carlsberg breweries, bequeathed his mansion (the Carlsberg Honorary Residence, currently known as Carlsberg Academy) to be used for life by the Dane who had made the most prominent contribution to science, literature or the arts, as an honorary residence (). Harald Høffding had been the first occupant, and upon his death in July 1931, the Royal Danish Academy of Sciences and Letters gave Bohr occupancy. He and his family moved there in 1932. He was elected president of the Academy on 17 March 1939.
By 1929 the phenomenon of beta decay prompted Bohr to again suggest that the law of conservation of energy be abandoned, but Enrico Fermi's hypothetical neutrino and the subsequent 1932 discovery of the neutron provided another explanation. This prompted Bohr to create a new theory of the compound nucleus in 1936, which explained how neutrons could be captured by the nucleus. In this model, the nucleus could be deformed like a drop of liquid. He worked on this with a new collaborator, the Danish physicist Fritz Kalckar, who died suddenly in 1938.
The discovery of nuclear fission by Otto Hahn in December 1938 (and its theoretical explanation by Lise Meitner) generated intense interest among physicists. Bohr brought the news to the United States where he opened the Fifth Washington Conference on Theoretical Physics with Fermi on 26 January 1939. When Bohr told George Placzek that this resolved all the mysteries of transuranic elements, Placzek told him that one remained: the neutron capture energies of uranium did not match those of its decay. Bohr thought about it for a few minutes and then announced to Placzek, Léon Rosenfeld and John Wheeler that "I have understood everything." Based on his liquid drop model of the nucleus, Bohr concluded that it was the uranium-235 isotope and not the more abundant uranium-238 that was primarily responsible for fission with thermal neutrons. In April 1940, John R. Dunning demonstrated that Bohr was correct. In the meantime, Bohr and Wheeler developed a theoretical treatment, which they published in a September 1939 paper on "The Mechanism of Nuclear Fission".
Philosophy
Heisenberg said of Bohr that he was "primarily a philosopher, not a physicist". Bohr read the 19th-century Danish Christian existentialist philosopher Søren Kierkegaard. Richard Rhodes argued in The Making of the Atomic Bomb that Bohr was influenced by Kierkegaard through Høffding. In 1909, Bohr sent his brother Kierkegaard's Stages on Life's Way as a birthday gift. In the enclosed letter, Bohr wrote, "It is the only thing I have to send home; but I do not believe that it would be very easy to find anything better ... I even think it is one of the most delightful things I have ever read." Bohr enjoyed Kierkegaard's language and literary style, but mentioned that he had some disagreement with Kierkegaard's philosophy. Some of Bohr's biographers suggested that this disagreement stemmed from Kierkegaard's advocacy of Christianity, while Bohr was an atheist.
There has been some dispute over the extent to which Kierkegaard influenced Bohr's philosophy and science. David Favrholdt argued that Kierkegaard had minimal influence over Bohr's work, taking Bohr's statement about disagreeing with Kierkegaard at face value, while Jan Faye argued that one can disagree with the content of a theory while accepting its general premises and structure.
Bohr sat on the Board of Editors of the book series World Perspectives which published a variety of books on philosophy.
Quantum physics
There has been much subsequent debate and discussion about Bohr's views and philosophy of quantum mechanics. Regarding his ontological interpretation of the quantum world, Bohr has been seen as an anti-realist, an instrumentalist, a phenomenological realist or some other kind of realist. Furthermore, though some have seen Bohr as being a subjectivist or a positivist, most philosophers agree that this is a misunderstanding of Bohr as he never argued for verificationism or for the idea that the subject had a direct impact on the outcome of a measurement.
Bohr has often been quoted saying that there is "no quantum world" but only an "abstract quantum physical description". This was not publicly said by Bohr, but rather a private statement attributed to Bohr by Aage Petersen in a reminiscence after his death. N. David Mermin recalled Victor Weisskopf declaring that Bohr wouldn't have said anything of the sort and exclaiming, "Shame on Aage Petersen for putting those ridiculous words in Bohr's mouth!"
Numerous scholars have argued that the philosophy of Immanuel Kant had a strong influence on Bohr. Like Kant, Bohr thought distinguishing between the subject's experience and the object was an important condition for attaining knowledge. This can only be done through the use of causal and spatial-temporal concepts to describe the subject's experience. Thus, according to Jan Faye, Bohr thought that it is because of "classical" concepts like "space", "position", "time", "causation", and "momentum" that one can talk about objects and their objective existence. Bohr held that basic concepts like "time" are built in to our ordinary language and that the concepts of classical physics are merely a refinement of them. Therefore, for Bohr, classical concepts need to be used to describe experiments that deal with the quantum world. Bohr writes:
[T]he account of all evidence must be expressed in classical terms. The argument is simply that by the word 'experiment' we refer to a situation where we can tell to others what we have done and what we have learned and that, therefore, the account of the experimental arrangement and of the results of the observations must be expressed in unambiguous language with suitable application of the terminology of classical physics (APHK, p. 39).
According to Faye, there are various explanations for why Bohr believed that classical concepts were necessary for describing quantum phenomena. Faye groups explanations into five frameworks: empiricism (i.e. logical positivism); Kantianism (or Neo-Kantian models of epistemology); Pragmatism (which focus on how human beings experientially interact with atomic systems according to their needs and interests); Darwinianism (i.e. we are adapted to use classical type concepts, which Léon Rosenfeld said that we evolved to use); and Experimentalism (which focuses strictly on the function and outcome of experiments that thus must be described classically). These explanations are not mutually exclusive, and at times Bohr seems to emphasise some of these aspects while at other times he focuses on other elements.
According to Faye "Bohr thought of the atom as real. Atoms are neither heuristic nor logical constructions." However, according to Faye, he did not believe "that the quantum mechanical formalism was true in the sense that it gave us a literal ('pictorial') rather than a symbolic representation of the quantum world." Therefore, Bohr's theory of complementarity "is first and foremost a semantic and epistemological reading of quantum mechanics that carries certain ontological implications". As Faye explains, Bohr's indefinability thesis is that
[T]he truth conditions of sentences ascribing a certain kinematic or dynamic value to an atomic object are dependent on the apparatus involved, in such a way that these truth conditions have to include reference to the experimental setup as well as the actual outcome of the experiment.
Faye notes that Bohr's interpretation makes no reference to a "collapse of the wave function during measurements" (and indeed, he never mentioned this idea). Instead, Bohr "accepted the Born statistical interpretation because he believed that the ψ-function has only a symbolic meaning and does not represent anything real". Since for Bohr, the ψ-function is not a literal pictorial representation of reality, there can be no real collapse of the wavefunction.
A much debated point in recent literature is what Bohr believed about atoms and their reality and whether they are something else than what they seem to be. Some like Henry Folse argue that Bohr saw a distinction between observed phenomena and a transcendental reality. Jan Faye disagrees with this position and holds that for Bohr, the quantum formalism and complementarity was the only thing we could say about the quantum world and that "there is no further evidence in Bohr's writings indicating that Bohr would attribute intrinsic and measurement-independent state properties to atomic objects [...] in addition to the classical ones being manifested in measurement."
Second World War
Assistance to refugee scholars
The rise of Nazism in Germany prompted many scholars to flee their countries, either because they were Jewish or because they were political opponents of the Nazi regime. In 1933, the Rockefeller Foundation created a fund to help support refugee academics, and Bohr discussed this programme with the President of the Rockefeller Foundation, Max Mason, in May 1933 during a visit to the United States. Bohr offered the refugees temporary jobs at the institute, provided them with financial support, arranged for them to be awarded fellowships from the Rockefeller Foundation, and ultimately found them places at institutions around the world. Those that he helped included Guido Beck, Felix Bloch, James Franck, George de Hevesy, Otto Frisch, Hilde Levi, Lise Meitner, George Placzek, Eugene Rabinowitch, Stefan Rozental, Erich Ernst Schneider, Edward Teller, Arthur von Hippel and Victor Weisskopf.
In April 1940, early in the Second World War, Nazi Germany invaded and occupied Denmark. To prevent the Germans from discovering Max von Laue's and James Franck's gold Nobel medals, Bohr had de Hevesy dissolve them in aqua regia. In this form, they were stored on a shelf at the Institute until after the war, when the gold was precipitated and the medals re-struck by the Nobel Foundation. Bohr's own medal had been donated to an auction to the Finnish Relief Fund, and was auctioned off in March 1940, along with the medal of August Krogh. The buyer later donated the two medals to the Danish Historical Museum in Frederiksborg Castle, where they are still kept, although Bohr's medal temporarily went to space with Andreas Mogensen on ISS Expedition 70 in 2023-2024.
Bohr kept the Institute running, but all the foreign scholars departed.
Meeting with Heisenberg
Bohr was aware of the possibility of using uranium-235 to construct an atomic bomb, referring to it in lectures in Britain and Denmark shortly before and after the war started, but he did not believe that it was technically feasible to extract a sufficient quantity of uranium-235. In September 1941, Heisenberg, who had become head of the German nuclear energy project, visited Bohr in Copenhagen. During this meeting the two men took a private moment outside, the content of which has caused much speculation, as both gave differing accounts.
According to Heisenberg, he began to address nuclear energy, morality and the war, to which Bohr seems to have reacted by terminating the conversation abruptly while not giving Heisenberg hints about his own opinions. Ivan Supek, one of Heisenberg's students and friends, claimed that the main subject of the meeting was Carl Friedrich von Weizsäcker, who had proposed trying to persuade Bohr to mediate peace between Britain and Germany.
In 1957, Heisenberg wrote to Robert Jungk, who was then working on the book Brighter than a Thousand Suns: A Personal History of the Atomic Scientists. Heisenberg explained that he had visited Copenhagen to communicate to Bohr the views of several German scientists, that production of a nuclear weapon was possible with great efforts, and this raised enormous responsibilities on the world's scientists on both sides. When Bohr saw Jungk's depiction in the Danish translation of the book, he drafted (but never sent) a letter to Heisenberg, stating that he deeply disagreed with Heisenberg's account of the meeting, that he recalled Heisenberg's visit as being to encourage cooperation with the inevitably victorious Nazis and that he was shocked that Germany was pursuing nuclear weapons under Heisenberg's leadership.
Michael Frayn's 1998 play Copenhagen explores what might have happened at the 1941 meeting between Heisenberg and Bohr. A television film version of the play by the BBC was first screened on 26 September 2002, with Stephen Rea as Bohr. With the subsequent release of Bohr's letters, the play has been criticised by historians as being a "grotesque oversimplification and perversion of the actual moral balance" due to adopting a pro-Heisenberg perspective.
The same meeting had previously been dramatised by the BBC's Horizon science documentary series in 1992, with Anthony Bate as Bohr, and Philip Anthony as Heisenberg. The meeting is also dramatised in the Norwegian/Danish/British miniseries The Heavy Water War.
Manhattan Project
In September 1943, word reached Bohr and his brother Harald that the Nazis considered their family to be Jewish, since their mother was Jewish, and that they were therefore in danger of being arrested. The Danish resistance helped Bohr and his wife escape by sea to Sweden on 29 September. The next day, Bohr persuaded King Gustaf V of Sweden to make public Sweden's willingness to provide asylum to Jewish refugees. On 2 October 1943, Swedish radio broadcast that Sweden was ready to offer asylum, and the mass rescue of the Danish Jews by their countrymen followed swiftly thereafter. Some historians claim that Bohr's actions led directly to the mass rescue, while others say that, though Bohr did all that he could for his countrymen, his actions were not a decisive influence on the wider events. Eventually, over 7,000 Danish Jews escaped to Sweden.
When the news of Bohr's escape reached Britain, Lord Cherwell sent a telegram to Bohr asking him to come to Britain. Bohr arrived in Scotland on 6 October in a de Havilland Mosquito operated by the British Overseas Airways Corporation (BOAC). The Mosquitos were unarmed high-speed bomber aircraft that had been converted to carry small, valuable cargoes or important passengers. By flying at high speed and high altitude, they could cross German-occupied Norway, and yet avoid German fighters. Bohr, equipped with parachute, flying suit and oxygen mask, spent the three-hour flight lying on a mattress in the aircraft's bomb bay. During the flight, Bohr did not wear his flying helmet as it was too small, and consequently did not hear the pilot's intercom instruction to turn on his oxygen supply when the aircraft climbed to high altitude to overfly Norway. He passed out from oxygen starvation and only revived when the aircraft descended to lower altitude over the North Sea. Bohr's son Aage followed his father to Britain on another flight a week later, and became his personal assistant.
Bohr was warmly received by James Chadwick and Sir John Anderson, but for security reasons Bohr was kept out of sight. He was given an apartment at St James's Palace and an office with the British Tube Alloys nuclear weapons development team. Bohr was astonished at the amount of progress that had been made. Chadwick arranged for Bohr to visit the United States as a Tube Alloys consultant, with Aage as his assistant. On 8 December 1943, Bohr arrived in Washington, D.C., where he met with the director of the Manhattan Project, Brigadier General Leslie R. Groves Jr. He visited Einstein and Pauli at the Institute for Advanced Study in Princeton, New Jersey, and went to Los Alamos in New Mexico, where the nuclear weapons were being designed. For security reasons, he went under the name of "Nicholas Baker" in the United States, while Aage became "James Baker". In May 1944 the Danish resistance newspaper De frie Danske reported that they had learned that 'the famous son of Denmark Professor Niels Bohr' in October the previous year had fled his country via Sweden to London and from there travelled to Moscow from where he could be assumed to support the war effort.
Bohr did not remain at Los Alamos, but paid a series of extended visits over the course of the next two years. Robert Oppenheimer credited Bohr with acting "as a scientific father figure to the younger men", most notably Richard Feynman. Bohr is quoted as saying, "They didn't need my help in making the atom bomb." Oppenheimer gave Bohr credit for an important contribution to the work on modulated neutron initiators. "This device remained a stubborn puzzle", Oppenheimer noted, "but in early February 1945 Niels Bohr clarified what had to be done".
Bohr recognised early that nuclear weapons would change international relations. In April 1944, he received a letter from Peter Kapitza, written some months before when Bohr was in Sweden, inviting him to come to the Soviet Union. The letter convinced Bohr that the Soviets were aware of the Anglo-American project, and would strive to catch up. He sent Kapitza a non-committal response, which he showed to the authorities in Britain before posting. Bohr met Churchill on 16 May 1944, but found that "we did not speak the same language". Churchill disagreed with the idea of openness towards the Russians to the point that he wrote in a letter: "It seems to me Bohr ought to be confined or at any rate made to see that he is very near the edge of mortal crimes."
Oppenheimer suggested that Bohr visit President Franklin D. Roosevelt to convince him that the Manhattan Project should be shared with the Soviets in the hope of speeding up its results. Bohr's friend, Supreme Court Justice Felix Frankfurter, informed President Roosevelt about Bohr's opinions, and a meeting between them took place on 26 August 1944. Roosevelt suggested that Bohr return to the United Kingdom to try to win British approval. When Churchill and Roosevelt met at Hyde Park on 19 September 1944, they rejected the idea of informing the world about the project, and the aide-mémoire of their conversation contained a rider that "enquiries should be made regarding the activities of Professor Bohr and steps taken to ensure that he is responsible for no leakage of information, particularly to the Russians".
In June 1950, Bohr addressed an "Open Letter" to the United Nations calling for international cooperation on nuclear energy. In the 1950s, after the Soviet Union's first nuclear weapon test, the International Atomic Energy Agency was created along the lines of Bohr's suggestion. In 1957 he received the first ever Atoms for Peace Award.
Later years
Following the ending of the war, Bohr returned to Copenhagen on 25 August 1945, and was re-elected President of the Royal Danish Academy of Arts and Sciences on 21 September. At a memorial meeting of the Academy on 17 October 1947 for King Christian X, who had died in April, the new king, Frederik IX, announced that he was conferring the Order of the Elephant on Bohr. This award was normally awarded only to royalty and heads of state, but the king said that it honoured not just Bohr personally, but Danish science. Bohr designed his own coat of arms, which featured a taijitu (symbol of yin and yang) and a motto in , "opposites are complementary".
The Second World War demonstrated that science, and physics in particular, now required considerable financial and material resources. To avoid a brain drain to the United States, twelve European countries banded together to create CERN, a research organisation along the lines of the national laboratories in the United States, designed to undertake Big Science projects beyond the resources of any one of them alone. Questions soon arose regarding the best location for the facilities. Bohr and Kramers felt that the Institute in Copenhagen would be the ideal site. Pierre Auger, who organised the preliminary discussions, disagreed; he felt that both Bohr and his Institute were past their prime, and that Bohr's presence would overshadow others. After a long debate, Bohr pledged his support to CERN in February 1952, and Geneva was chosen as the site in October. The CERN Theory Group was based in Copenhagen until their new accommodation in Geneva was ready in 1957. Victor Weisskopf, who later became the Director General of CERN, summed up Bohr's role, saying that "there were other personalities who started and conceived the idea of CERN. The enthusiasm and ideas of the other people would not have been enough, however, if a man of his stature had not supported it."
Meanwhile, Scandinavian countries formed the Nordic Institute for Theoretical Physics in 1957, with Bohr as its chairman. He was also involved with the founding of the Research Establishment Risø of the Danish Atomic Energy Commission, and served as its first chairman from February 1956.
Bohr died of heart failure at his home in Carlsberg on 18 November 1962. He was cremated, and his ashes were buried in the family plot in the Assistens Cemetery in the Nørrebro section of Copenhagen, along with those of his parents, his brother Harald, and his son Christian. Years later, his wife's ashes were also interred there. On 7 October 1965, on what would have been his 80th birthday, the Institute for Theoretical Physics at the University of Copenhagen was officially renamed to what it had been called unofficially for many years: the Niels Bohr Institute.
Accolades
Bohr received numerous honours and accolades. In addition to the Nobel Prize, he received the Hughes Medal in 1921, the Matteucci Medal in 1923, the Franklin Medal in 1926, the Copley Medal in 1938, the Order of the Elephant in 1947, the Atoms for Peace Award in 1957 and the Sonning Prize in 1961. He became foreign member of the Finnish Society of Sciences an Letters in 1922, and of the Royal Netherlands Academy of Arts and Sciences in 1923, an international member of the United States National Academy of Sciences in 1925, a member of the Royal Society in 1926, an international member of the American Philosophical Society in 1940, and an international honorary member of the American Academy of Arts and Sciences in 1945. The Bohr model's semicentennial was commemorated in Denmark on 21 November 1963 with a postage stamp depicting Bohr, the hydrogen atom and the formula for the difference of any two hydrogen energy levels: . Several other countries have also issued postage stamps depicting Bohr. In 1997, the Danish National Bank began circulating the 500-krone banknote with the portrait of Bohr smoking a pipe. On 7 October 2012, in celebration of Niels Bohr's 127th birthday, a Google Doodle depicting the Bohr model of the hydrogen atom appeared on Google's home page. An asteroid, 3948 Bohr, was named after him, as was the Bohr lunar crater, and bohrium, the chemical element with atomic number 107, in acknowledgement of his work on the structure of atoms.
Bibliography
See also
Einstein–Podolsky–Rosen paradox
Notes
References
Excerpted from:
(Previously published by John Wiley & Sons in 1964)
Further reading
Bohr's researches on reaction times.
External links
Niels Bohr Archive
Author profile in the database zbMATH
including the Nobel Lecture, 11 December 1922 The Structure of the Atom
Oral history interview transcript for Niels Bohr on 31 October 1962, American Institute of Physics, Niels Bohr Library & Archives – interviews conducted by Thomas S. Kuhn, Leon Rosenfeld, Erik Rudinger, and Aage Petersen
Oral history interview transcript for Niels Bohr on 1 November 1962, American Institute of Physics, Niels Bohr Library & Archives
Oral history interview transcript for Niels Bohr on 7 November 1962, American Institute of Physics, Niels Bohr Library & Archives
Oral history interview transcript for Niels Bohr on 14 November 1962, American Institute of Physics, Niels Bohr Library & Archives
Oral history interview transcript for Niels Bohr on 17 November 1962, American Institute of Physics, Niels Bohr Library & Archives
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Recipients of Franklin Medal | Niels Bohr | Physics | 9,360 |
5,347,173 | https://en.wikipedia.org/wiki/Lopinavir | Lopinavir is an antiretroviral of the protease inhibitor class. It is used against HIV infections as a fixed-dose combination with another protease inhibitor, ritonavir (lopinavir/ritonavir).
It was patented in 1995 and approved for medical use in 2000. Considered now as second-line therapy in the West, it is still prescribed in LMIC, especially among children living with HIV. Lopinavir and ritonavir can be taken as a tablet or an oral solution, a preferred option in children. In the early stages of COVID-19 pandemics, lopinavir was repurposed against the SARS-CoV-2 virus in the hope of disturbing its protease activity.
Side effects
Side effects, interactions, and contraindications have only been evaluated in the drug combination lopinavir/ritonavir. They include nausea, vomiting, and stomach aches.
Pharmacology
Lopinavir is highly bound to plasma proteins (98–99%).
Reports are contradictory regarding lopinavir penetration into the cerebrospinal fluid (CSF). Anecdotal reports state that lopinavir cannot be detected in the CSF; however, a study of paired CSF-plasma samples from 26 patients receiving lopinavir/ritonavir found lopinavir CSF levels above the IC50 in 77% of samples.
Research
A 2014 study indicates that lopinavir is effective against the human papilloma virus (HPV). The study used the equivalent of one tablet twice a day applied topically to the cervices of women with high-grade and low-grade precancerous conditions. After three months of treatment, 82.6% of the women who had high-grade disease had normal cervical conditions, confirmed by smears and biopsies. Lopinavir has been shown to impair protein synthesis via AMP-activated protein kinase (AMPK) and eEF2 kinase (eEF2K) activation, a mechanism that is similar to the antiviral effect of protein phosphatase 1 inhibitors.
Lopinavir was found to inhibit MERS-CoV replication in the low-micromolar range in cell cultures. In 2020, lopinavir/ritonavir was found not to work in severe COVID-19. In this trial the medication was started typically around 13 days after the start of symptoms.
A long-acting injectable formulation of lopinavir is under clinical trial aiming at monthly dosing (NCT05850728).
References
External links
CYP3A4 inhibitors
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Phenol ethers
Drugs developed by AbbVie
Pyrimidones
Ureas | Lopinavir | Chemistry | 577 |
13,593 | https://en.wikipedia.org/wiki/Java%20applet | Java applets are small applications written in the Java programming language, or another programming language that compiles to Java bytecode, and delivered to users in the form of Java bytecode.
At the time of their introduction, the intended use was for the user to launch the applet from a web page, and for the applet to then execute within a Java virtual machine (JVM) in a process separate from the web browser itself. A Java applet could appear in a frame of the web page, a new application window, a program from Sun called appletviewer, or a stand-alone tool for testing applets.
Java applets were introduced in the first version of the Java language, which was released in 1995. Beginning in 2013, major web browsers began to phase out support for NPAPI, the underlying technology applets used to run. with applets becoming completely unable to be run by 2015–2017. Java applets were deprecated by Java 9 in 2017.
Java applets were usually written in Java, but other languages such as Jython, JRuby, Pascal, Scala, NetRexx, or Eiffel (via SmartEiffel) could be used as well.
Unlike early versions of JavaScript, Java applets had access to 3D hardware acceleration, making them well-suited for non-trivial, computation-intensive visualizations. Since applets' introduction, JavaScript has gained support for hardware-accelerated graphics via canvas technology (or specifically WebGL in the case of 3D graphics), as well as just-in-time compilation.
Since Java bytecode is cross-platform (or platform independent), Java applets could be executed by clients for many platforms, including Microsoft Windows, FreeBSD, Unix, macOS and Linux. They could not be run on mobile devices, which do not support running standard Oracle JVM bytecode. Android devices can run code written in Java compiled for the Android Runtime.
Overview
The applets are used to provide interactive features to web applications that cannot be provided by HTML alone. They can capture mouse input and also have controls like buttons or check boxes. In response to user actions, an applet can change the provided graphic content. This makes applets well-suited for demonstration, visualization, and teaching. There are online applet collections for studying various subjects, from physics to heart physiology.
An applet can also be a text area only; providing, for instance, a cross-platform command-line interface to some remote system. If needed, an applet can leave the dedicated area and run as a separate window. However, applets have very little control over web page content outside the applet's dedicated area, so they are less useful for improving the site appearance in general, unlike other types of browser extensions (while applets like news tickers or WYSIWYG editors are also known). Applets can also play media in formats that are not natively supported by the browser.
Pages coded in HTML may embed parameters within them that are passed to the applet. Because of this, the same applet may have a different appearance depending on the parameters that were passed.
As applets were available before HTML5, modern CSS and JavaScript interface DOM were standard, they were also widely used for trivial effects such as mouseover and navigation buttons. This approach, which posed major problems for accessibility and misused system resources, is no longer in use and was strongly discouraged even at the time.
Technical information
Most browsers executed Java applets in a sandbox, preventing applets from accessing local data like the file system. The code of the applet was downloaded from a web server, after which the browser either embedded the applet into a web page or opened a new window showing the applet's user interface.
The first implementations involved downloading an applet class by class. While classes are small files, there are often many of them, so applets got a reputation as slow-loading components. However, since .jar files were introduced, an applet is usually delivered as a single file that has a size similar to an image file (hundreds of kilobytes to several megabytes).
Java system libraries and runtimes are backwards-compatible, allowing one to write code that runs both on current and on future versions of the Java virtual machine.
Similar technologies
Many Java developers, blogs and magazines recommended that the Java Web Start technology be used in place of applets. Java Web Start allowed the launching of unmodified applet code, which then ran in a separate window (not inside the invoking browser).
A Java Servlet is sometimes informally compared to be "like" a server-side applet, but it is different in its language, functions, and in each of the characteristics described here about applets.
Embedding into a web page
The applet would be displayed on the web page by making use of the deprecated applet HTML element, or the recommended object element. The embed element can be used with Mozilla family browsers (embed was deprecated in HTML 4 but is included in HTML 5). This specifies the applet's source and location. Both object and embed tags can also download and install Java virtual machine (if required) or at least lead to the plugin page. applet and object tags also support loading of the serialized applets that start in some particular (rather than initial) state. Tags also specify the message that shows up in place of the applet if the browser cannot run it due to any reason.
However, despite object being officially a recommended tag in 2010, the support of the object tag was not yet consistent among browsers and Sun kept recommending the older applet tag for deploying in multibrowser environments, as it remained the only tag consistently supported by the most popular browsers. To support multiple browsers, using the object tag to embed an applet would require JavaScript (that recognizes the browser and adjusts the tag), usage of additional browser-specific tags or delivering adapted output from the server side.
The Java browser plug-in relied on NPAPI, which nearly all web browser vendors have removed support for, or do not implement, due to its age and security issues. In January 2016, Oracle announced that Java runtime environments based on JDK 9 will discontinue the browser plug-in.
Advantages
A Java applet could have any or all of the following advantages:
It was simple to make it work on FreeBSD, Linux, Microsoft Windows and macOS that is, to make it cross-platform. Applets were supported by most web browsers through the first decade of the 21st century; since then, however, most browsers have dropped applet support for security reasons.
The same applet would work on "all" installed versions of Java at the same time, rather than just the latest plug-in version only. However, if an applet requires a later version of the Java Runtime Environment (JRE) the client would be forced to wait during the large download.
Most web browsers cached applets so they were quick to load when returning to a web page. Applets also improved with use: after a first applet is run, the JVM was already running and subsequent applets started quickly (the JVM will need to restart each time the browser starts afresh). JRE versions 1.5 and greater restarted the JVM when the browser navigates between pages, as a security measure which removed that performance gain.
It moved work from the server to the client, making a web solution more scalable with the number of users/clients.
If a standalone program (like Google Earth) talks to a web server, that server normally needs to support all prior versions for users who have not kept their client software updated. In contrast, a browser loaded (and cached) the latest applet version, so there is no need to support legacy versions.
Applet naturally supported changing user state, such as figure positions on the chessboard.
Developers could develop and debug an applet directly simply by creating a main routine (either in the applet's class or in a separate class) and calling init() and start() on the applet, thus allowing for development in their favorite Java SE development environment. All one had to do was to re-test the applet in the AppletViewer program or a web browser to ensure it conforms to security restrictions.
An untrusted applet had no access to the local machine and can only access the server it came from. This makes applets much safer to run than the native executables that they would replace. However, a signed applet could have full access to the machine it is running on, if the user agreed.
Java applets were fast, with similar performance to natively installed software.
Disadvantages
Java applets had the following disadvantages compared to other client-side web technologies:
Java applets would depend on a Java Runtime Environment (JRE), a complex and heavy-weight software package. They also normally required a plug-in for the web browser. Some organizations only allow software installed by an administrator. As a result, users were unable to view applets unless one was important enough to justify contacting the administrator to request installation of the JRE and plug-in.
If an applet requires a newer JRE than available on the system, the user running it the first time will need to wait for the large JRE download to complete.
Mobile browsers on iOS or Android, never run Java applets at all. Even before the deprecation of applets on all platforms, desktop browsers phased out Java applet support concurrently with the rise of mobile operating systems.
There was no standard to make the content of applets available to screen readers. Therefore, applets harmed the accessibility of a web site to users with special needs.
As with any client-side scripting, security restrictions made it difficult or even impossible for some untrusted applets to achieve their desired goals. Only by editing the java.policy file in the JAVA JRE installation could one grant access to the local filesystem or system clipboard, or to network sources other than the one that served the applet to the browser.
Most users did not care about the difference between untrusted and trusted applets, so this distinction did not help much with security. The ability to run untrusted applets was eventually removed entirely to fix this, before all applets were removed.
Compatibility-related lawsuits
Sun made considerable efforts to ensure compatibility is maintained between Java versions as they evolve, enforcing Java portability by law if required. Oracle seems to be continuing the same strategy.
1997: Sun vs Microsoft
The 1997 lawsuit, was filed after Microsoft created a modified Java Virtual Machine of their own, which shipped with Internet Explorer. Microsoft added about 50 methods and 50 fields into the classes within the java.awt, java.lang, and java.io packages. Other modifications included removal of RMI capability and replacement of Java Native Interface from JNI to RNI, a different standard. RMI was removed because it only easily supports Java to Java communications and competes with Microsoft DCOM technology. Applets that relied on these changes or just inadvertently used them worked only within Microsoft's Java system. Sun sued for breach of trademark, as the point of Java was that there should be no proprietary extensions and that code should work everywhere. Microsoft agreed to pay Sun $20 million, and Sun agreed to grant Microsoft limited license to use Java without modifications only and for a limited time.
2002: Sun vs Microsoft
Microsoft continued to ship its own unmodified Java virtual machine. Over the years it became extremely outdated yet still default for Internet Explorer. A later study revealed that applets of this time often contain their own classes that mirror Swing and other newer features in a limited way. In 2002, Sun filed an antitrust lawsuit, claiming that Microsoft's attempts at illegal monopolization had harmed the Java platform. Sun demanded Microsoft distribute Sun's current, binary implementation of Java technology as part of Windows, distribute it as a recommended update for older Microsoft desktop operating systems and stop the distribution of Microsoft's Virtual Machine (as its licensing time, agreed in the prior lawsuit, had expired). Microsoft paid $700 million for pending antitrust issues, another $900 million for patent issues and a $350 million royalty fee to use Sun's software in the future.
Security
There were two applet types with very different security models: signed applets and unsigned applets. Starting with Java SE 7 Update 21 (April 2013) applets and Web-Start Apps are encouraged to be signed with a trusted certificate, and warning messages appear when running unsigned applets. Further, starting with Java 7 Update 51 unsigned applets were blocked by default; they could be run by creating an exception in the Java Control Panel.
Unsigned
Limits on unsigned applets were understood as "draconian": they have no access to the local filesystem and web access limited to the applet download site; there are also many other important restrictions. For instance, they cannot access all system properties, use their own class loader, call native code, execute external commands on a local system or redefine classes belonging to core packages included as part of a Java release. While they can run in a standalone frame, such frame contains a header, indicating that this is an untrusted applet. Successful initial call of the forbidden method does not automatically create a security hole as an access controller checks the entire stack of the calling code to be sure the call is not coming from an improper location.
As with any complex system, many security problems have been discovered and fixed since Java was first released. Some of these (like the Calendar serialization security bug) persisted for many years with nobody being aware. Others have been discovered in use by malware in the wild.
Some studies mention applets crashing the browser or overusing CPU resources but these are classified as nuisances and not as true security flaws. However, unsigned applets may be involved in combined attacks that exploit a combination of multiple severe configuration errors in other parts of the system. An unsigned applet can also be more dangerous to run directly on the server where it is hosted because while code base allows it to talk with the server, running inside it can bypass the firewall. An applet may also try DoS attacks on the server where it is hosted, but usually people who manage the web site also manage the applet, making this unreasonable. Communities may solve this problem via source code review or running applets on a dedicated domain.
The unsigned applet can also try to download malware hosted on originating server. However it could only store such file into a temporary folder (as it is transient data) and has no means to complete the attack by executing it. There were attempts to use applets for spreading Phoenix and Siberia exploits this way, but these exploits do not use Java internally and were also distributed in several other ways.
Signed
A signed applet contains a signature that the browser should verify through a remotely running, independent certificate authority server. Producing this signature involves specialized tools and interaction with the authority server maintainers. Once the signature is verified, and the user of the current machine also approves, a signed applet can get more rights, becoming equivalent to an ordinary standalone program. The rationale is that the author of the applet is now known and will be responsible for any deliberate damage. This approach allows applets to be used for many tasks that are otherwise not possible by client-side scripting. However, this approach requires more responsibility from the user, deciding whom he or she trusts. The related concerns include a non-responsive authority server, wrong evaluation of the signer identity when issuing certificates, and known applet publishers still doing something that the user would not approve of. Hence signed applets that appeared from Java 1.1 may actually have more security concerns.
Self-signed
Self-signed applets, which are applets signed by the developer themselves, may potentially pose a security risk; java plugins provide a warning when requesting authorization for a self-signed applet, as the function and safety of the applet is guaranteed only by the developer itself, and has not been independently confirmed. Such self-signed certificates are usually only used during development prior to release where third-party confirmation of security is unimportant, but most applet developers will seek third-party signing to ensure that users trust the applet's safety.
Java security problems are not fundamentally different from similar problems of any client-side scripting platform. In particular, all issues related to signed applets also apply to Microsoft ActiveX components.
As of 2014, self-signed and unsigned applets are no longer accepted by the commonly available Java plugins or Java Web Start. Consequently, developers who wish to deploy Java applets have no alternative but to acquire trusted certificates from commercial sources.
Alternatives
Alternative technologies exist (for example, WebAssembly and JavaScript) that satisfy all or more of the scope of what was possible with an applet. JavaScript could coexist with applets in the same page, assist in launching applets (for instance, in a separate frame or providing platform workarounds) and later be called from the applet code. As JavaScript gained in features and performance, the support for and use of applets declined, until their eventual removal.
See also
ActiveX
Adobe Flash Player
Curl (programming language)
Jakarta Servlet
Java Web Start
JavaFX
Rich web application
SWF
WebGL
Silverlight
References
External links
Latest version of Sun Microsystems' Java Virtual Machine (includes browser plug-ins for running Java applets in most web browsers).
Information about writing applets from Oracle
Demonstration applets from Sun Microsystems (JDK 1.4 include source code)
Java (programming language)
Java platform
Web 1.0 | Java applet | Technology | 3,697 |
11,755,005 | https://en.wikipedia.org/wiki/Ovulitis%20azaleae | Ovulitis azaleae is a plant pathogen affecting azaleas and rhododendrons.
See also
List of azalea diseases
List of rhododendron diseases
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Ornamental plant pathogens and diseases
Sclerotiniaceae
Fungus species | Ovulitis azaleae | Biology | 72 |
36,393,632 | https://en.wikipedia.org/wiki/USA-199 | USA-199, also known as GPS IIR-18(M), GPS IIRM-5 and GPS SVN-57, is an American navigation satellite which forms part of the Global Positioning System. It was the fifth of eight Block IIRM satellites to be launched, and the eighteenth of twenty one Block IIR satellites overall. It was built by Lockheed Martin, using the AS-4000 satellite bus.
USA-199 was launched at 20:04:00 UTC on 20 December 2007, atop a Delta II carrier rocket, flight number D331, flying in the 7925-9.5 configuration. The launch took place from Space Launch Complex 17A at the Cape Canaveral Air Force Station, and placed USA-199 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37FM apogee motor.
By 15 February 2008, USA-199 was in an orbit with a perigee of , an apogee of , a period of 717.98 minutes, and 54.9 degrees of inclination to the equator. It is used to broadcast the PRN 29 signal, and operates in slot 1 of plane C of the GPS constellation. The satellite has a design life of 10 years and a mass of . As of 2012 it remains in service.
References
Spacecraft launched in 2007
GPS satellites
USA satellites | USA-199 | Technology | 275 |
61,519,996 | https://en.wikipedia.org/wiki/C22H17F2N5OS | {{DISPLAYTITLE:C22H17F2N5OS}}
The molecular formula C22H17F2N5OS (molar mass: 437.465 g/mol, exact mass: 437.1122 u) may refer to:
Isavuconazonium
Ravuconazole
Molecular formulas | C22H17F2N5OS | Physics,Chemistry | 72 |
62,119 | https://en.wikipedia.org/wiki/Bradford%27s%20law | Bradford's law is a pattern first described by Samuel C. Bradford in 1934 that estimates the exponentially diminishing returns of searching for references in science journals. One formulation is that if journals in a field are sorted by number of articles into three groups, each with about one-third of all articles, then the number of journals in each group will be proportional to 1:n:n2. There are a number of related formulations of the principle.
In many disciplines, this pattern is called a Pareto distribution. As a practical example, suppose that a researcher has five core scientific journals for his or her subject. Suppose that in a month there are 12 articles of interest in those journals. Suppose further that in order to find another dozen articles of interest, the researcher would have to go to an additional 10 journals. Then that researcher's Bradford multiplier bm is 2 (i.e. 10/5). For each new dozen articles, that researcher will need to look in bm times as many journals. After looking in 5, 10, 20, 40, etc. journals, most researchers quickly realize that there is little point in looking further.
Different researchers have different numbers of core journals, and different Bradford multipliers. But the pattern holds quite well across many subjects, and may well be a general pattern for human interactions in social systems. Like Zipf's law, to which it is related, we do not have a good explanation for why it works, but knowing that it does is very useful for librarians. What it means is that for each specialty, it is sufficient to identify the "core publications" for that field and only stock those; very rarely will researchers need to go outside that set.
However, its impact has been far greater than that. Armed with this idea and inspired by Vannevar Bush's famous article As We May Think, Eugene Garfield at the Institute for Scientific Information in the 1960s developed a comprehensive index of how scientific thinking propagates. His Science Citation Index (SCI) had the effect of making it easy to identify exactly which scientists did science that had an impact, and which journals that science appeared in. It also caused the discovery, which some did not expect, that a few journals, such as Nature and Science, were core for all of hard science. The same pattern does not happen with the humanities or the social sciences.
The result of this is pressure on scientists to publish in the best journals, and pressure on universities to ensure access to that core set of journals. On the other hand, the set of "core journals" may vary more or less strongly with the individual researchers, and even more strongly along schools-of-thought divides. There is also a danger of over-representing majority views if journals are selected in this fashion.
Scattering
Bradford's law is also known as Bradford's law of scattering or the Bradford distribution, as it describes how the articles on a particular subject are scattered throughout the mass of periodicals. Another more general term that has come into use since 2006 is information scattering, an often observed phenomenon related to information collections where there are a few sources that have many items of relevant information about a topic, while most sources have only a few. This law of distribution in bibliometrics can be applied to the World Wide Web as well.
Hjørland and Nicolaisen identified three kinds of scattering:
Lexical scattering. The scattering of words in texts and in collections of texts.
Semantic scattering. The scattering of concepts in texts and in collections of texts.
Subject scattering. The scattering of items useful to a given task or problem.
They found that the literature of Bradford's law (including Bradford's own papers) is unclear in relation to which kind of scattering is actually being measured.
Law's interpretations
The interpretation of Bradford's law in terms of a geometric progression was suggested by V. Yatsko, who introduced an additional constant and demonstrated that Bradford distribution can be applied to a variety of objects, not only to distribution of articles or citations across journals. V. Yatsko's interpretation (Y-interpretation) can be effectively used to compute threshold values in case it is necessary to distinguish subsets within a set of objects (successful/unsuccessful applicants, developed/underdeveloped regions, etc.).
Related laws and distributions
Benford's law, originally used to explain apparently non-uniform sampling
Lotka's law, describes the frequency of publication by authors in any given field.
Power law, a general mathematical form for "heavy-tailed" distributions, with a polynomial density function. In this form, these laws may all be expressed and estimates derived.
Zeta distribution
Zipf's law, originally used for word frequencies
Zipf–Mandelbrot law
See also
PageRank
The Long Tail
Notes
References
Bradford, Samuel C., Sources of Information on Specific Subjects, Engineering: An Illustrated Weekly Journal (London), 137, 1934 (26 January), pp. 85–86.
Reprinted as:
Bradford, Samuel C. Sources of information on specific subjects, Journal of Information Science, 10:4, 1985 (October), pp. 173–180
Nicolaisen, Jeppe; and Hjørland, Birger (2007), Practical potentials of Bradford's law: A critical examination of the received view, Journal of Documentation, 63(3): 359–377. Available here and here
Suresh K. Bhavnani, Concepcio´n S. Wilson, Information Scattering. Available
Lancaster, F. W., & Pontigo J. (1986). Qualitative aspects of the Bradford distribution. Scientometrics, 9(1–2), 59–70.
External links
In Oldenburg's Long Shadow: Librarians, Research Scientists, Publishers, and the Control of Scientific Publishing
Bibliometrics
Computational linguistics
Statistical laws | Bradford's law | Mathematics,Technology | 1,203 |
40,613,802 | https://en.wikipedia.org/wiki/Hispanic%20Scientist%20of%20the%20Year%20Award | The Museum of Science & Industry (Tampa) honors a Hispanic scientist every year since 2001. MOSI awards a Scientist every year to provide role models for the diverse youth of the Tampa Bay area.
2001
The 2001 honoree was Dr. Alejandro Acevedo-Gutierrez, a Marine Biologist from Mexico.
2002
The 2002 honoree was Fernando "Frank" Caldeiro, a NASA Astronaut from Argentina.
2003
The 2003 honoree was Dr. Mario Molina, a Nobel Laureate in Chemistry from Mexico.
2004
Dr. Antiona Coello Novello was the 2004 honoree, and she was the U.S. Surgeon General from 1990 to 1993. She is originally from Puerto Rico.
2005
Dr. Edmond Yunis was the 2005 honoree, and he is an Immunologist from Colombia.
2006
The 2006 honoree was Dr. Ines Cifuentes, a Seismologist from England, Ecuador, and America.
2007
Dr. Louis A. Martin-Vega is an Industrial Engineer from America and Puerto Rico, and he was the 2007 honoree.
2008
The 2008 honoree was Dr. Lydia Villa-Komaroff, a Molecular Biologist from America and Mexico.
2009
Dr. Nils Diaz, the former chair of the U.S. Nuclear Regulatory Commission, was the 2009 honoree, and he is from Cuba.
2010
Dr. Dan Arvizu, the 2010 honoree, is the Director and Chief Executive of the U.S. Department of Energy's National Renewable Energy Laboratory, and he is from Mexico.
2011
Dr. Cristian Samper, Director of the Smithsonian Institution's National Museum of Natural History, was the 2011 honoree, and he is from Colombia.
2012
Dr. Nora Volkow, the Director of the National Institute on Drug Abuse (NIDA) at the National Institutes of Health, was the 2012 honoree, and she is originally from Mexico.
2013
Dr. Raul Cuero, Inventor and Microbiologist, is the 2013 honoree, and he is from Colombia
.
2014
Dr. Rafael L. Bras, Civil Engineer, Puerto Rico.
Prize expanded to include an Early Career Honoree: Dr. Ana Maria Rey, Physicist, Colombia.
2015
Dr. Modesto Alex Maidique, Electrical Engineer, Cuba.
Early Career Honoree: Dr. Miguel Morales Silva, Physicist, Puerto Rico.
2016
Dr. Adriana Ocampo, Planetary Geologist, USA.
References
Science and technology awards | Hispanic Scientist of the Year Award | Technology | 491 |
45,288,828 | https://en.wikipedia.org/wiki/High-performance%20instrumented%20airborne%20platform%20for%20environmental%20research | The high-performance instrumented airborne platform for environmental research (HIAPER) is a modified Gulfstream V aircraft operated by the Earth Observing Laboratory at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado. The aircraft was purchased brand-new from Gulfstream Aerospace in 2002 and then modified by Lockheed Martin in Greenville, South Carolina over a period of two years, for a total cost of $80 million.
The aircraft includes a wing mounted cloud radar which allows researchers a high resolution view into snow producing storms. The aircraft is designed and instrumented to observe and measure clouds from the stratosphere.
The HIAPER cloud radar (HCR) is an airborne, polarimetric, millimeter-wavelength radar capable of cloud remote sensing. Whole air samplers also collect air samples for later analysis on the ground.
Data collected by the 2013 HIAPER Pole-to-Pole Observations (HIPPO) campaign is publicly available.
References
External links
Current location of the HAIPR and other NCAR research aircraft
HIPPO Data Archive
Gulfstream aircraft
Meteorological instrumentation and equipment
2000s United States aircraft | High-performance instrumented airborne platform for environmental research | Technology,Engineering | 222 |
5,296,754 | https://en.wikipedia.org/wiki/Samarium%28III%29%20fluoride | Samarium(III) fluoride (SmF3) is a slightly hygroscopic solid fluoride. Conditions/substances to avoid are: open flame, moisture, strong acids.
Preparation
Samarium(III) fluoride can be obtained by reacting SmCl3 or Sm2(CO3)3 with 40% hydrofluoric acid:
Samarium(III) fluoride can also be produced by hydrothermal reaction of samarium nitrate and sodium fluroborate at 200 °C.
Properties
Chemical
Samarium(III) fluoride reacts with some reducing agents at high temperatures to obtain samarium(II) fluoride:
Physical
At room temperature, samarium(III) fluoride has orthorhombic structure with space group Pnma – β-YF3 type with lattice constants a = 666,9 pm, b = 705,9 pm, c = 440,5 pm. Above 495 °C, it has the rhombohedral LaF3 structure (space group P3cl) – with lattice constants a = 707, c = 724 pm.
References
Fluorides
Lanthanide halides
Samarium(III) compounds | Samarium(III) fluoride | Chemistry | 248 |
20,943,074 | https://en.wikipedia.org/wiki/Acetylenic | In organic chemistry, the term acetylenic designates
A doubly unsaturated position (sp-hybridized) on a molecular framework, for instance in an alkyne such as acetylene;
An ethynyl fragment, HCC–, or substituted homologue.
See also
Allylic
Propargylic
Vinylic
Organic chemistry | Acetylenic | Chemistry | 74 |
59,466,172 | https://en.wikipedia.org/wiki/Geophis%20dunni | Geophis dunni, Dunn's earth snake, is a species of enigmatic snake in the family Colubridae. The species is presumably endemic to Nicaragua and is only known from a single specimen discovered in 1932. This specimen, the holotype, was discovered by Karl Patterson Schmidt in the stomach of a Central American coral snake, and no additional specimen has been seen since. The holotype has a snout-to-vent length (SVL) of , a tail length of , and a total length of . It is part of the Geophis sieboldi species group according to Floyd Leslie Downs. This species was named by Schmidt after fellow herpetologist Emmett Reid Dunn "in allusion to his important contributions to our knowledge of this group of snakes".
This species is little known for several reasons. Snakes of the genus Geophis are fossorial and nocturnal, and as such are rarely observed in their natural habitat even by those actively searching for them. Also, the snakes of this genus form extensive species complexes in which the only way to tell them apart is by slight differences. For example, Geophis dunni differs from other species by having 17 dorsal scale rows, 8 infralabial scales, and 140 ventral scales. Additionally, the type locality given by Schmidt is very vague, only being "Matagalpa, Nicaragua". Matagalpa is both a city and a municipality, and no data for elevation or habitat type were specified either. However, Downs would mark a location in north Nicaragua at an elevation of as being the type locality of this snake, but this location is exactly the city of Matagalpa and has been questioned by other papers on its accuracy. As of 2022, Geophis dunni remains "data deficient" until another individual is collected and a habitat is identified.
Reproduction
G. dunni is oviparous.
References
Geophis
Snakes of Central America
Reptiles of Nicaragua
Endemic fauna of Nicaragua
Taxa named by Karl Patterson Schmidt
Reptiles described in 1932
Species known from a single specimen | Geophis dunni | Biology | 419 |
17,345,761 | https://en.wikipedia.org/wiki/List%20of%20image-sharing%20websites | This article presents a non-exhaustive list of notable image-sharing websites.
Active image-sharing websites
Defunct photo-sharing websites
These also include sites that may still operate, but do not accept new users. Listed in chronological order of shutdown.
Comparison of photo-sharing websites
Legend:
File formats: the image or video formats allowed for uploading
IPTC support: support for the IPTC image header
Yes - IPTC headers are read upon upload and exposed via the web interface; properties such as captions and keywords are written back to the IPTC header and saved along with the photo when downloading or e-mailing it
Some - IPTC headers are read but information added via the web interface is not saved back to the IPTC header; or, IPTC headers are lost on resizing
Tags/keywords: the ability to add to and search by tags or keywords
Comments: the ability of users to leave comments on the photo
Yes - full control over who can leave comments (friends, registered users, non-registered users)
Some - users must register with the website to leave comments
Rating:
Yes - star rating: the ability to rate photos numerically, usually on a scale from 1 to 5
Some - thumbs up/down rating, "mark as favorite", or a rating system accessible only to logged-in users
Download originals:
Yes - anyone can download the original photo
Some - only photos of "pro" members can be downloaded
Notes/annotations: the ability to overlay textual notes to areas of a photo
Friendly URLs: human-readable URLs (e.g. /photos/greece_album/athens.jpg) vs. numeric identifiers (MemViewImage.asp?AID=5610943&IID=205062034&INUM=5&ICT=5&IPP=16)
Subscriptions
Some - RSS feeds and web interface
Yes - RSS feeds, web interface, plus photo updates can be sent by e-mail to non-registered members
See also
Digital photo frame
File-hosting service
File sharing
Image hosting service
Image sharing
List of photo and video apps
Timeline of file sharing
References
Dynamic lists
Lists of photography topics
Lists of websites
Online services comparisons | List of image-sharing websites | Technology | 464 |
6,738,560 | https://en.wikipedia.org/wiki/Engin%20Blind%C3%A9%20du%20G%C3%A9nie | The Engin Blindé du Génie (EBG; "armoured engineering vehicle") is a French military engineering vehicle. Its chassis is that of the AMX-30 battle tank.
Development of the vehicle began in the 1980s. It was pressed into service by the French Army in 1989 for the Gulf War, which revealed that the design needed further work. Deliveries to the French Army resumed in the early 1990s.
The vehicle carries a 142-mm demolition gun, a dozer blade, a manipulator arm, launchers for anti-tank mines, a winch and a 7.62-mm machine gun. It has a three-person crew of a commander, driver and operator. Of 71 vehicles built, 18 of the modernised EBG VAL or EBG R2 variant remained in operational service in 2018, with some others of it in long-term storage.
EBG SDPMAC is a minefield-breaching variant. The EBG VAL or EBG R2 variant has additional armour and other improvements. The most recent variant is the EBG Vulcain, which has an excavator arm instead of a manipulator arm; the first one was delivered in 2020, and three more were due in 2021.
References
Armoured fighting vehicles of France
Military engineering vehicles | Engin Blindé du Génie | Engineering | 271 |
40,545,481 | https://en.wikipedia.org/wiki/Ministry%20of%20Energy%20%28Saudi%20Arabia%29 | The Ministry of Energy () is a government ministry in Saudi Arabia and part of the cabinet. It is responsible for developing and implementing policies concerning petroleum and related products. The Ministry of Energy is working to diversify the national energy mix used in electricity production, increasing the share of natural gas and renewable energy sources to approximately 50% by 2030 while reducing the use of liquid fuel.
In August 2019, King Salman issued a royal decree and divided the Ministry of Petroleum and Mineral Resources into two: Ministry of Industry and Mineral Resources, and Ministry of Energy. While Khalid al-Falih still remained the energy minister, business executive Bandar Al-Khorayef was named as the minister of natural resources. However, on 8 September 2019, a royal decree was issued to appoint Abdulaziz bin Salman Al Saud as the energy minister.
History
The ministry was established in December 1960. Prior to the formation of the ministry policies regarding oil production and planning were overseen by the directorate general of petroleum and mineral affairs which was attached to the ministry of finance. Then the directorate was converted into the ministry. The ministry was named the Ministry of Petroleum and Mineral Resources until May 2016 when it was renamed as the Ministry of Energy, Industry and Mineral Resources. In August 2019, the Ministry was separated into the Ministry of Energy and the Ministry of Industry and Mineral Resources.
List of ministers
Since 1960 the ministry was headed by the following six ministers:
Abdullah Tariki (December 1960 – 9 March 1962)
Ahmed Zaki Yamani (9 March 1962 – 5 October 1986)
Hisham Nazer (24 December 1986 – 2 August 1995)
Ali Naimi (2 August 1995 – 7 May 2016)
Khalid A. Al-Falih (7 May 2016 – 8 September 2019)
Abdulaziz bin Salman Al Saud (8 September 2019 – present)
Organization and activities
The ministry is primarily responsible for the policies concerning oil and gas in the country which is the world's largest holder of crude oil reserves. One of the agencies with which the ministry works is Petromin, the general petroleum and mineral organization. Through Saudi Arabian Basic Industries Company (SABIC), established in 1976, the ministry oversaw the operation of petrochemicals and other heavy industry projects.
In 2019, the Minister inaugurated the launching ceremony of the Saudi scientific vessel, called “Najil” in Jubail port, Eastern Province. The main aim of the vessel is to conduct marine-related researches in the Persian Gulf and the Red Sea.
In 2019, and on the sidelines of the Saudi crown prince’s visit to India, the Minister of Energy, Industry and Mineral Resources signed a MOU to partner with the International Solar Alliance (ISA) and projects in fertilizers, pharmaceuticals and medical supplies.
See also
Ministries of Saudi Arabia
OPEC
Saudi Aramco
References
Energy
Saudi Arabia
Saudi Arabia
1960 establishments in Saudi Arabia
Economy of Saudi Arabia
Saudi Aramco | Ministry of Energy (Saudi Arabia) | Engineering | 591 |
35,888,911 | https://en.wikipedia.org/wiki/Arctic%20GmbH | Arctic GmbH, formerly known as Arctic Cooling, is a German, Swiss-founded manufacturer of computer cooling components, mainly CPU and graphics card coolers, case fans and thermal compound. Since 2010, Arctic expanded its business by starting a range of products to cater other consumer demands beyond that of computer cooling hardware. Nowadays, Arctic also offers various consumer products—spanning audio, home entertainment and computer peripherals. In 2012, Arctic was nominated as one of the finalists in the annual PCR Awards.
Founded in 2001, Arctic has offices in Germany, Hong Kong and the United States and cooperates with different production facilities in China. Arctic products are distributed worldwide through distributors, dealers and retailers. The United States, United Kingdom and Germany are Arctic's major markets. The company has also collaborated with leading graphics card brands such as HIS, Inno3D, PowerColor, VTX3D, and Sapphire in the development of OEM cooling equipment.
History
In 2001, Arctic Cooling was founded in Switzerland by Magnus Huber. As the company name suggested, in the past, the business focused entirely on computer cooling solutions. Today, in order to expand the business into other areas especially in consumer electronics, by 2010, it began to develop a diverse range of products that spans beyond cooling into computer peripherals, audio products and home entertainment PCs. For this reason, Arctic Cooling was changed to Arctic in 2010. Since 17.11.2015 Arctic Switzerland AG is in liquidation.
Logo
Products
Computer cooling
Being the company's original focus, Arctic primarily designs and manufactures cooling products for computer hardware, with broad compatibility. The company owned a number of patents for its fan and cooler designs as well as for special technologies used in the air coolers including PWM sharing, low noise impeller, cross blow and anti-vibration technologies.
Freezer
Freezer is a trademark of Arctic for its line of CPU coolers. It includes both the air cooler based on a heatpipe architecture as well as the water cooling solutions.
Alpine
Alpine is a trademark of Arctic for its line of CPU coolers based on Aluminum extrusion heatsink. It includes both active and passive coolers.
Accelero
Accelero is a trademark of Arctic (formerly Arctic Cooling) for its line of graphics card coolers. The Accelero line of coolers are targeted to high-end graphics cards based on GPUs from Nvidia and AMD. The Accelero series utilizes different types of cooling technologies namely air cooling, passive cooling as well as to offer different options for different customers. In 2006, Accelero X1 and Accelero X2 are the first VGA coolers introduced in the series by the manufacturer. The Accelero series has collaborated in a number of OEM projects with motherboard and video card manufacturers to develop customized graphics card cooling solutions. Arctic is the first video card cooler manufacturer to use a copper base for their heatsinks.
In May 2012, ARCTIC released the Accelero Hybrid, which is claimed to be the world's first graphics card cooler with integrated air and liquid solution in the market.
Features
Graphics card coolers are generally served as an upgrade or replacement for the stock cooler in order to reduce noise, temperature and enhance the overclocking capability of the GPU. Arctic's heatsinks are claimed to provide quiet, high performance cooling, which also makes the Accelero series one of the most popular graphics card coolers in the market.
Thermal compound
Among the company's array of thermal compound, the MX-4 received the Top Product Award from the German magazine PC Games Hardware.
MX-6
MX-4
MX-2
PC case
Silentium T11
Silentium T Eco 80
Fusion Power Supplies and Storage Devices
Fusion is Arctic's brand name for various cooling and data storage products, including the Fusion 550- EU, Fusion 550RF, Fusion 550R, Fusion 550F and Fusion 1TB (external hard drive), and the Fusion 1TB data storage device.
Audio series
Arctic started to develop its audio products such as speakers, headphones and headsets since 2010 and it has expanded to wireless audio system near the end of 2011.
Living series
In June 2011, Arctic entered the HTPC market with its first mini HTPC, MC001 Entertainment Center Series, which was first introduced in Computex 2011. In 2012, Arctic introduced more advanced models with MC101 Series, AMD Trinity-powered HTPCs which are aimed for multimedia users. The MC101 Series features AMD Trinity A8/A10 APU, AMD Radeon HD 3D graphics, up to 1TB hard disk storage, SSD, up to 8GB DDR3 memory and built-in TV tuner.
On top of the entertainment centers, Arctic offers as well an audio gateway that works as a Windows Media Center Extender : Audio Relay. It is not DLNA certified but is compatible with the protocol.
Due to limited commercial success, this product line has been discontinued.
Computer peripherals
Arctic offers a selection of computer peripherals including keyboards, mice, USB fans, etc. In the end of 2011, the brand started to offer Apple accessories.
Power series
The Power series offers various USB travel adapters, car chargers and batteries.
Patents and trademarks
The company has claimed several trademarks and patents for the name and technology applied to their products. Some of the air coolers and case fans produced by the company feature a patent design of the fan holder to achieve vibration absorption and elimination of the buzzing sound when the fan is running. The Freezer 7 Pro features 4 rubber connectors which serve as a vibration damper to absorb the vibration of the running fan and prevent the vibration from transferring to the heatsink and the case. The Arctic F Pro PWM employs the same technology to absorb vibration and prevent it from transmitting across other components within the case.
Arctic claims to be the patent holder of the PWM Sharing Technology, namely PST, which shares a single PWM signal with all the other PWM controlled devices connected to the motherboard to control all fan speeds and enhance the noise level according to the load.
The Freezer 13 PRO CO employs the patented Cross-Blow technology by the use of an extra fan installed at the bottom of the heatsink to give a boost of cooling performance to the surrounding components, including Northbridge and voltage regulators.
The company utilizes its patented passive cooling technology (DE 20200600) in the Accelero S1 PLUS to enhance the level of natural convection from the GPU by letting more air to pass through the aluminum fins so that heat will be dissipated more efficiently.
Some of the key products including Freezer, Accelero, Alpine, Fusion and Silentium series are registered trademarks in the EU and the US.
Branding
In 2011, Arctic has started to engage its end consumers through the means of social media (e.g. Facebook) to reinforce the brand's awareness. The company was also a platinum partner with PCR Retail Boot Camp – a new conference and expo for the UK PC and IT channel.
Collaborations
Arctic also produces cooling solutions for several graphic card manufactures; in most cases improving cooling beyond the OEM cooler. These include but are not limited to:
AMD (formerly ATI)
Club 3D
ECS
Galaxy
Hightech Information System (HIS)
Inno3D
TUL (PowerColor)
Sapphire Technology
Sparkle
Zotac
Partnership with OpenELEC
Due to the strategic mistake of bundling the MC001 with Microsoft Windows 7 and the high price the MC001 was very badly sold. To increase sales, on 5 February 2013, Arctic announced their new partnership with OpenELEC. Arctic worked with OpenELEC together and combined a fully passive cooled entertainment system - the MC001 media centre (US and EU version) equipped with the latest XBMC 12 (OpenELEC 3.0) platform. Arctic and OpenELEC were planning on their next release, aimed to provide a more dedicated builds for the Arctic MC001 systems. Shortly after partnershipping with OpenELEC, the development of passively cooled media centers was abandoned.
Dispute
Arctic was reportedly planning to file a lawsuit against AMD for the infringement of its trademark "Fusion", the name that AMD used to describe its series of APUs which integrate x86 processing cores with Radeon stream processors on the same piece of silicon. In light of the lawsuit, AMD has announced earlier in 2012 its plans to drop its Fusion branding in favor of the Heterogeneous Systems Architecture (HSA). On 23 January 2013, Arctic announced that the company and AMD arrived at a mutual agreement in settling the "Fusion" trademark dispute without any disclosure of the terms.
References
External links
Headphones manufacturers
Computer companies of Germany
Computer hardware companies
Computer hardware cooling
Computer peripheral companies
Technology companies established in 2001
Swiss brands
Audio equipment manufacturers of Switzerland | Arctic GmbH | Technology | 1,804 |
35,046,077 | https://en.wikipedia.org/wiki/Abell%202390 | Abell 2390 is a massive galaxy cluster located in the constellation Pegasus. It is classified as an X-ray and rich galaxy clusters measured cooling rate of 200-300 Mʘyr−1. The galaxy cluster contains a cD galaxy called Abell 2390 BCG (short for brightest cluster galaxy), associated with a complex radio source, B2151+141.
A study has been conducted on the galaxy members of Abell 2390 and finds each of them have different morphology classifications. Further evidence also points out only a few galaxies show star formations, indicating starbursts play no major role in propelling the galaxy cluster's evolution.
Based on weak gravitational distortion of galaxies lying in the background, dark matter distribution is detected in Abell 2390. Its X-ray distribution in the cluster is elliptical and distorted by its sub-structure on a large scale according to an X-ray ROSAT/HRI observation.
Abell 2390 BCG
The brightest cluster galaxy of Abell 2390 is the supergiant elliptical galaxy, LEDA 140982. It is a Fanaroff-Riley class II radio galaxy hosting a luminous powerful radio source with extended optical emission lines. According to studies published in 2006, the source of LEDA 140982 is found peculiar with a misaligned, compact twin radio jet structure created by the host galaxy's apparent structure. Based on evidence, it might be caused by the precession of its central supermassive black hole. Another study shows the galaxy also contains molecular gas, with some located in a one-sided plume from the galaxy's center.
See also
Abell catalogue
List of Abell clusters
X-ray astronomy
References
2390
Galaxy clusters
Abell richness class 1
Pegasus (constellation) | Abell 2390 | Astronomy | 357 |
63,498,181 | https://en.wikipedia.org/wiki/Adawro%20exclosure | Adawro is an exclosure located in the Dogu'a Tembien woreda of the Tigray Region in Ethiopia. The area has been protected by the local community since 1994.
Environmental characteristics
Average slope gradient: 70%
Aspect: the exclosure is oriented towards the northeast
Minimum altitude: 2635 metres
Maximum altitude: 2705 metres
Lithology: Basalt
Management
As a general rule, cattle ranging and wood harvesting are not allowed. The grasses are harvested once yearly and taken to the homesteads of the village to feed livestock. Physical soil and water conservation has been implemented to enhance infiltration, and vegetation growth.
Benefits for the community
Setting aside such areas fits with the long-term vision of the communities were hiza’iti lands are set aside for use by the future generations. It has also direct benefits for the community:
improved infiltration
improved ground water availability
honey production
climate ameliorator (temperature, moisture)
carbon sequestration, dominantly sequestered in the soil, and additionally in the woody vegetation)
Water conservation
In the Adawro exclosure, more than 800 precise measurements were done in 2003 and 2004, using five runoff plots, where the volume of runoff was measured daily. The rock type (basalt), slope gradient and slope aspect were the same, the only difference was the land management and vegetation density. Whereas in degraded rangeland, 11.4% of the rainfall flows directly away to the river (runoff coefficient), this happens only for 2.5% of the rain in a recent exclosure and 3.2% in a eucalyptus forest.
In 2003, the soils of the then young exclosure could hold 280 litres of water per m³, similar to the adjacent rangeland.
Improved ecosystem
With vegetation growth, biodiversity in this exclosure has strongly improved: there is more varied vegetation and wildlife.
Trees
The main tree species found in the exclosure are:
Flat top acacia (Acacia abyssinica, renamed as Vachellia abyssinica)
Golden wattle (Acacia saligna)
Rumex nervosus, a woody sorrel species
Aloe macrocarpa
Soils
Main soil type in the exclosure are Phaeozems, formed in sediment that has been trapped by the vegetation of the exclosure, and as a remnant of the original situation before deforestation. Remarkably, also in the well-protected eucalypt plantation there is some undergrowth and soil development.
References
External links
Link For Forestry Projects
Exclosures of Tigray Region
1999 establishments in Ethiopia
Land management
Environmental conservation
Environmentalism in Ethiopia
Emissions reduction
Dogu'a Tembien | Adawro exclosure | Chemistry | 551 |
22,180,696 | https://en.wikipedia.org/wiki/GIS%20and%20public%20health | Geographic information systems (GISs) and geographic information science (GIScience) combine computer-mapping capabilities with additional database management and data analysis tools. Commercial GIS systems are very powerful and have touched many applications and industries, including environmental science, urban planning, agricultural applications, and others.
Public health is another focus area that has made increasing use of GIS techniques. A strict definition of public health is difficult to pin down, as it is used in different ways by different groups. In general, public health differs from personal health in that it is (1) focused on the health of populations rather than of individuals, (2) focused more on prevention than on treatment, and (3) operates in a mainly governmental (rather than private) context. These efforts fall naturally within the domain of problems requiring use of spatial analysis as part of the solution, and GIS and other spatial analysis tools are therefore recognized as providing potentially transformational capabilities for public health efforts.
This article presents some history of use of geographic information and geographic information systems in public health application areas, provides some examples showing the utilization of GIS techniques in solving specific public health problems, and finally addresses several potential issues arising from increased use of these GIS techniques in the public health arena.
History
Public health efforts have been based on analysis and use of spatial data for many years. Dr. John Snow (physician), often credited as the father of epidemiology, is arguably the most famous of those examples. Dr. Snow used a hand-drawn map to analyze the geographic locations of deaths related to cholera in London in the mid-1850s. His map, which superimposed the locations of cholera deaths with those of public water supplies, pinpointed the Broad Street pump as the most likely source of the cholera outbreak. Removal of the pump handle led to a rapid decline in the incidence of cholera, helping the medical community to eventually conclude that cholera was a water-borne disease.
Dr. Snow's work provides an indication of how a GIS could benefit public health investigations and other research. He continued to analyze his data, eventually showing that the incidence rate of cholera was also related to local elevation as well as soil type and alkalinity. Low-lying areas, particularly those with poorly draining soil, were found to have higher incidence rates for cholera, which Dr. Snow attributed to the pools of water that tended to collect there, again showing evidence that cholera was in fact a water-borne disease (rather than one borne by 'miasma' as was commonly believed at the time.
This is an early example of what has come to be known as disease diffusion mapping, an area of study based on the idea that a disease starts from some source or central point and then spreads throughout the local area according to patterns and conditions there. This is another area of research where the capabilities of a GIS have been shown to be of help to practitioners.
GIS for public health
Today’s public health problems are much larger in scope than those Dr. Snow faced, and researchers today depend on modern GIS and other computer mapping applications to assist in their analyses. For example, see the map to the right depicting death rates from heart disease among white males above age 35 in the US between 2000 and 2004.
Public health informatics (PHI) is an emerging specialty which focuses on the application of information science and technology to public health practice and research. As part of that effort, a GIS – or more generally a spatial decision support system (SDSS) – offers improved geographic visualization techniques, leading to faster, better, and more robust understanding and decision-making capabilities in the public health arena.
For example, GIS displays have been used to show engagement with online health information during infectious disease pandemics, as well as associations between clusters of emergent Hepatitis C cases and those of known intravenous drug users in Connecticut. Causality is difficult to prove conclusively – collocation does not establish causation – but confirmation of previously established causal relationships (like intravenous drug use and Hepatitis C) can strengthen acceptance of those relationships, as well as help to demonstrate the utility and reliability of GIS-related solution techniques. Conversely, showing the coincidence of potential causal factors with the ultimate effect can help suggest a potential causal relationship, thereby driving further investigation and analysis
Alternately, GIS techniques have been used to show a lack of correlation between causes and effects or between different effects. For example, the distributions of both birth defects and infant mortality in Iowa were studied, and the researchers found no relationship in those data. This led to the conclusion that birth defects and infant mortality are likely unrelated, and are likely due to different causes and risk factors.
GIS can support public health in different ways as well. First and foremost, GIS displays can help inform proper understanding and drive better decisions. For example, elimination of health disparities is one of two primary goals of Healthy People 2010, one of the preeminent public health programs in existence today in the US. GIS can play a significant role in that effort, helping public health practitioners identify areas of disparities or inequities, and ideally helping them identify and develop solutions to address those shortcomings. GIS can also help researchers integrate disparate data from a wide variety of sources, and can even be used to enforce quality control measures on those data. Much public health data is still manually generated, and is therefore subject to human-generated mistakes and miscoding. For example, geographic analysis of health care data from North Carolina showed that just over 40% of the records contained errors of some sort in the geographic information (city, county, or zip code), errors that would have gone undetected without the visual displays provided by GIS. Correction of these errors led not only to more correct GIS displays, but also improved ALL analyses using those data.
Issues with GIS for public health
There are also concerns or issues with use of GIS tools for public health efforts. Chief among those is a concern for privacy and confidentiality of individuals. Public health is concerned about the health of the population as a whole, but must use data on the health of individuals to make many of those assessments, and protecting the privacy and confidentiality of those individuals is of paramount importance. Use of GIS displays and related databases raises the potential of compromising those privacy standards, so some precautions are necessary to avoid pinpointing individuals based on spatial data. For example, data may need to be aggregated to cover larger areas such as a census tract or county, helping to mask individual identities. Maps can also be constructed at smaller scales so that less detail is revealed. Alternately, key identifying features (such as the road and street network) can be left off the maps to mask exact location, or it may even be advisable to intentionally offset the location markers by some random amount if deemed necessary.
It is well established in the literature that statistical inference based on aggregated data can lead researchers to erroneous conclusions, suggesting relationships that in fact do not exist or obscuring relationships that do in fact exist. This issue is known as the modifiable areal unit problem. For example, New York public health officials worried that cancer clusters and causes would be misidentified after they were forced to post maps showing cancer cases by ZIP code on the internet. Their assertion was that ZIP codes were designed for a purpose unrelated to public health issues, and so use of these arbitrary boundaries might lead to inappropriate groupings and then to incorrect conclusions. Further, when comparing data in different aerial units, the difference in size and population means that comparing totals can hide underlying trends in the data. This issue is particularly prevalent with choropleth maps. To solve this, cartographers often apply some form of normalization, such as cases per 100,000 people. Unfortunately, this practice is not always adhered to and can cause potentially misleading maps.
Summary
Use of GIS in public health is an application area still in its infancy. Like most new applications, there is a lot of promise, but also a lot of pitfalls that must be avoided along the way. Many researchers and practitioners are concentrating of this effort, hoping that the benefits outweigh the risks and the costs associated with this emerging application area for modern GIS techniques.
See also
Arbia's law of geography
boundary problem
Biogeography
Cartography
Concepts and Techniques in Modern Geography
distance decay
ecological fallacy
geography
Geospatial predictive modeling
geographic information systems
geographic information science
modifiable areal unit problem
Public health
spatial analysis
spatial autocorrelation
Spatial epidemiology
Time geography
Tobler's first law of geography
Tobler's second law of geography
Transportation geography
Uncertain geographic context problem
Urban geography
Waldo Tobler
Footnotes
External links
National Center for Health Statistics
GIS and Public Health at Esri
GIS for Public Health Mapping
International Journal of Health Geographics
Applications of geographic information systems
Spatial analysis
Health informatics
Public health | GIS and public health | Physics,Biology | 1,822 |
61,309,845 | https://en.wikipedia.org/wiki/Cefoperazone/sulbactam | Cefoperazone/sulbactam is a combination drug used as an antibiotic. It is effective for the treatment of urinary tract infections. It contains cefoperazone, a β-lactam antibiotic, and sulbactam, a β-lactamase inhibitor, which helps prevent bacteria from breaking down cefoperazone.
References
Drugs developed by Pfizer
Combination antibiotics
Antibiotics | Cefoperazone/sulbactam | Biology | 88 |
20,560,610 | https://en.wikipedia.org/wiki/Kenneth%20Loch | Lieutenant General Sir Kenneth Morley Loch, KCIE, KBE, CB, MC, (18 September 1890 – 9 January 1961) was a Scottish soldier in the British Army and defence planner.
Early life and military career
Born on 18 September 1890, Loch was educated at Wellington College, Berkshire and the Royal Military Academy, Woolwich, and, upon passing out from the latter, received a commission as a second lieutenant into the Royal Artillery on 23 December 1910. He saw action during World War I at the retreat from Mons and the battles of the Marne and Aisne, all in 1914. Leaving the front lines in 1916 he became an instructor in gunnery at the School of Instruction for the Royal Horse Artillery and the Royal Field Artillery until he returned to front line service in the Italian Campaign of 1918. During the war Loch was twice mentioned in dispatches and received the Military Cross (MC).
Between the wars
Between the wars Loch remained in the army and attended the Staff College, Camberley from 1923 to 1924. His fellow students included numerous future general officers, such as Dudley Johnson, John Smyth, Arthur Wakely, Montagu Stopford, Arthur Percival, Douglas Henry Pratt, Robert Stone, John Halsted, Frederick Pile, Michael Gambier-Parry, Henry Wemyss, Robert Pargiter, Edmond Schreiber, Alastair MacDougall, Roderic Petre, Balfour Hutchison, Leslie Hill and Gordon Macready. He was involved in air defence preparations for Britain around the British Empire. From 1926 to 1929 he was a General Staff Officer Grade 2 (GSO2) to the Territorial Army (TA) Air Defence Formations, and from 1932 to 1935 an instructor at the Staff College, Quetta; GSO2 at the War Office, 1935–1937, and GSO1, Royal Air Force (RAF) Fighter Command, 1937–1938.
World War II
From the beginning of World War II until 1941, Loch was Director of Anti-Aircraft and Coastal Defence, first as acting major-general, then from 25 November 1940 as temporary major-general. He argued successfully against the use of chemical weapons in case of a German invasion of Britain (see Operation Sea Lion). After a three-year tour of inspection of anti-aircraft defences in the British Empire (a Special Employment), he became Master-General of Ordnance, India, from 1944 until his retirement in 1947. After retiring the service Loch was with the British Council from 1947 to 1948, then served as a member of the Control Commission for Germany, 1948–1949, and returned to the British Council from 1950 to 1958. He was also Chairman of Governors of Wellington College.
In 1929 Loch married Monica Joan Estelle Ruffer, the daughter of a German banker, and had two sons. He was also the uncle of the Labour Member of Parliament Tam Dalyell.
Bibliography
References
External links
Generals of World War II
Scottish generals
British Army generals of World War II
British Army personnel of World War I
1890 births
1961 deaths
Knights Commander of the Order of the Indian Empire
Knights Commander of the Order of the British Empire
Companions of the Order of the Bath
Recipients of the Military Cross
Royal Artillery officers
People educated at Wellington College, Berkshire
Chemical warfare
Graduates of the Staff College, Camberley
Graduates of the Royal Military Academy, Woolwich
British Army lieutenant generals | Kenneth Loch | Chemistry | 671 |
69,968,655 | https://en.wikipedia.org/wiki/Hairpin%20technology | Hairpin technology is a winding technology for stators in electric motors and generators and is also used for traction applications in electric vehicles. In contrast to conventional winding technologies, the hairpin technology is based on solid, flat copper bars which are inserted into the stator stack. These copper bars, also known as hairpins, consist of enameled copper wire bent into a U-shape, similar to the geometry of hairpins.
In addition to hairpins with U-shape, there are two other variants of bar windings, the so-called I-pin technology and the concept of continuous hairpin windings.
I-Pins are straight copper wire elements that are inserted into the stator slots. Unlike Hairpins, these Pins are not bent prior to insertion into stack. However, contacting is necessary on both sides of the stator. In the concept of continuous hairpin windings, so-called winding mats are produced and afterwards inserted into the stack from the inner diameter.
Hairpin stators are most commonly used for synchronous machines.
Stator structure
The structure of a hairpin stator differs from conventional stators only in the type of winding system - other components of the stator are little changed. The stack of sheets consists of many layers of individual sheets, each insulated by a thin coating. The housing is another subcomponent that does not generally require modifications. The thin, round wire of the conventional winding technology is substituted by copper bars, which better fit the slot geometry and therefore provide a higher slot-filling degree than regular winding. To create the necessary winding scheme, the free ends of the hairpins are twisted before welding. In addition to the impregnation process for the entire stator, which is also necessary for conventionally wound stators, a layer of insulation resin is applied to the ends of the hairpins.
Manufacturing
The hairpin stator process chain is based on an indirect winding approach. Due to the solid cross section, hairpins can be shaped into their final geometry ahead of the actual assembly process. In contrast to conventional stator production, in which winding-based assembly processes predominate, a forming process is applied.
Production can be divided into 4 steps:
Hairpin
In the first process, a flat copper wire, which is usually already enameled, is continuously unwound and straightened in several stages to reduce residual curvature and stresses. In preparation for welding of the copper ends in a later process step, this insulation is partially removed. Laser-based and mechanical processes are feasible. The hairpin wire is cut to length and bent, in varying order. Hairpins are formed into a three-dimensional geometry either in a single-stage process using special CNC bending equipment or in multiple stages in which a die bending process follows a swivel bending process. There are three technologies for bending hairpin wires: U-Pin, in which hairpin wires have a shape resembling a U, I-Pin, with wires resemling an I, and Continuous Hairpin, also called continuous wave, in which a single wire is bent into a serpentine shape up to several meters long. U-Pin technology is the most common of these.
Assembly and twisting
Next the pins are inserted into the stator stack. The insertion process is limited by overlaps in the winding head geometry. The hairpins are usually pre-assembled in an assembly nest. Individual pins are arranged in accordance with the winding scheme. In general, a single hairpin stator uses 3-16 different hairpin geometries. The stator slots are lined with insulation paper to separate the winding system from the ground potential of the stator's sheet stack.
In the next assembly step, the hairpin basket is inserted axially into the stator stack. To support the insertion the hairpins are sometimes equipped with chamfers during the cutting process – grippers can improve positioning precision.
Each layer of hairpin ends is twisted in accordance with the winding scheme. During the associated rotation the tool has to be moved in an axial direction for height compensation. To ensure axial accessibility the hairpin ends must be radially exposed in a preparatory step.
Welding and interconnection
Next, hairpin ends are electrically contacted with each other to form the winding scheme. Using a laser, the hairpin ends are partially melted and joined. An optimal welding process is marked by homogenous weld geometries as well as minimal thermal input. Repeatable welding strategies require the stator to maintain a stable condition.
Relative height and lateral offset of the hairpin end can cause welding defects. These can be prevented by corrective processes that are dependent on precise tolerances within upstream processes. Phase jumps and the main electroconductive connection of the entire winding can be carried out through connective elements or assemblies connect to the welded hairpin ends. This can also be done via laser welding. Examples of interconnection elements are contact rings, terminals, and bridges.
Insulation
After the winding process, the welded copper ends are re-insulated and the entire stator is impregnated. Powder coating or polyurethane-based resins are commonly used to insulate the copper ends. Typically, dipping, trickling, or potting processes are used. The impregnation process differs little from those used for conventional stators, such as dipping or trickling processes. The purpose of impregnation is to protect the stator from thermal, electrical, ambient, and mechanical influences.
Testing
A variety of tests are performed throughout the production process. Ensuring function- and safety-relevant properties of the stator is a key objective. Common tests are:
Partial discharge testing
Surge voltage testing
Resistance testing
Geometric testing
Challenges
Particularly in traction drives, a major implementation challenge is process reliability, particularly bending and welding processes. The bending process must not damage the insulation and exactly match the required geometry. Incorrectly welded hairpin ends can cause electrical losses – and possibly a non-functioning stator.
Key target parameters are high fill factors within the stator slots and a small winding head. Due to the rectangular and enlarged conductor cross section, fill factors can reach 73% (significantly higher than the 45-50% in conventionally wound stators). A small winding head increases relative active material and thus the proportion that generates power. However, hairpin's larger cross sectioncan result in additional electrical losses, e.g., due to current displacement effects such as the skin effect.
Automotive industry
Due to deterministic assembly processes, good speed-torque behavior, and high fill factors, hairpin technology has gained appeal for automotive applications. Additionally, the hairpin production process is suitable for automation. As a result, shorter cycle times and increasing quantities lead to decreasing production costs.
Hairpin technology is increasingly applied in automotive applications. The first production vehicle with hairpin technology was the 2008 General Motors Chevrolet Tahoe hybrid featuring 2 motors with this stator construction in GM's 2ML70 "2Mode" transmission.
The Volkswagen Group relies on hairpin stators in its electric vehicles, including the ID.3, ID.4 the Audi e-tron GT, and the Porsche Taycan. The BMW iX3 is the company's first vehicle to employ hairpin stators. In 2021, General Motors unveiled its new motor line up that includes a 64 kW ASM for hybrid applications and a 255 kW PSM in the Hummer EV. In 2023, Tesla announced that its next generation motor would use hairpins.
Research
Government and industry are funding hairpin technology research projects. These include::
Pro-E-Traktion (Production, BMW AG)
HaPiPro2 (Production, PEM of RWTH Aachen University)
AnStaHa (Production, Karlsruhe Institute of Technology)
IPANEMA (Machine Learning, API Hard- and Software GmbH)
KIPrEMo (Artificial Intelligence, FAPS of FAU Erlangen-Nürnberg)
KIKoSA (Artificial Intelligence, FAPS of FAU Erlangen-Nürnberg)
Further reading
Kampker/Schnetter/Vallée: Elektromobilität. 2nd rev. edition, 2018, Springer Berlin Heidelberg,
Gläßel, Tobias: Prozessketten zum Laserstrahlschweißen von flachleiterbasierten Formspulenwicklungen für automobile Traktionsantriebe. FAU Studien aus dem Maschinenbau Band 354. Juli 2020, Erlangen, FAU University Press,
VDMA/Raßmann: Produktionsprozess eines Hairpin-Stators. 1st edition, Oktober 2019,
References
External links
VDMA: Production process of Hairpin stators
Schaeffler eDrive Plattform: Benefits and Disadvantages of a Hairpin stator
Electric motors | Hairpin technology | Technology,Engineering | 1,799 |
70,473,759 | https://en.wikipedia.org/wiki/Nissan%20NR%20engine | The Nissan NR is a family of prototype four-stroke 2.0-litre single-turbocharged inline-4 racing engine, developed and produced by Nissan for the Super GT series under the Nippon Race Engine framework. The engine has been produced in a number of different configurations over the years. The NR engine is fully custom-built.
Versions
All versions of the engine are identical in performance.
NR20A (2014–2019)
NR20B (2020)
NR4S21 (2021–2023)
NR4S24 (2024–present)
Applications
Nissan GT-R NISMO GT500
Nissan Fairlady Z NISMO GT500
See also
Honda HR-414E/HR-417E/HR-420E engine, similar engines also developed under the Nippon Race Engine framework
Toyota RI engine, similar engine also developed under the Nippon Race Engine framework
References
Engines by model
Gasoline engines by model
NR
Four-cylinder engines
Straight-four engines
Nissan in motorsport | Nissan NR engine | Technology | 196 |
1,041,473 | https://en.wikipedia.org/wiki/Kavli%20Institute%20for%20Theoretical%20Physics | The Kavli Institute for Theoretical Physics (KITP) is a research institute of the University of California, Santa Barbara dedicated to theoretical physics. KITP is one of 20 Kavli Institutes.
The National Science Foundation has been the principal supporter of the institute since it was founded as the Institute for Theoretical Physics in 1979. In a 2007 article in the Proceedings of the National Academy of Sciences, KITP was given the highest impact index in a comparison of nonbiomedical research organizations across the United States.
About
In the early 2000s, the institute, formerly known as the Institute for Theoretical Physics, or ITP, was named after businessman and philanthropist Fred Kavli, in recognition of his donation of $7.5 million to the institute.
Kohn Hall, which houses KITP, is located just beyond the Henley Gate at the East Entrance of the UCSB campus. The building was designed by the Driehaus Prize winner and New Classical architect Michael Graves, and a new wing designed by Graves was added in 2003–2004.
Members
The directors of the KITP have been:
Walter Kohn, 1979–1984 (Nobel Prize in Chemistry, 1998)
Robert Schrieffer, 1984–1989 (Nobel Prize for Physics, 1972)
James S. Langer, 1989–1995 (Oliver Buckley Prize (APS), 1997)
James Hartle, 1995–1997 (Einstein Prize (APS), 2009)
David Gross, 1997–2012 (Nobel Prize in Physics, 2004)
Lars Bildsten, 2012–present (Helen B. Warner Prize (AAS), 1999; Dannie Heineman Prize for Astrophysics (AAS & American Institute of Physics), 2017)
The Director, Deputy Director Mark Bowick, and Permanent Members of the KITP (Leon Balents, Lars Bildsten, David Gross, and Boris Shraiman) are also on the faculty of the UC Santa Barbara Physics Department. Former Permanent Members include Joseph Polchinski and Physics Nobel laureate Frank Wilczek.
See also
Institute for Theoretical Physics (disambiguation)
Center for Theoretical Physics (disambiguation)
Kavli Institute for Particle Astrophysics and Cosmology
Kavli Institute for the Physics and Mathematics of the Universe
References
External links
The KITP web site
University of California, Santa Barbara
Research institutes in California
Physics research institutes
Michael Graves buildings
Kavli Institutes
Theoretical physics institutes
New Classical architecture in the United States | Kavli Institute for Theoretical Physics | Physics | 496 |
78,819,121 | https://en.wikipedia.org/wiki/Chiodectonic%20acid | Chiodectonic acid is an organic compound in the structural class of chemicals known as anthraquinones. It occurs as a secondary metabolite in some lichens.
History
The red pigment "pyxiferin" was first isolated from the lichen Pyxine coccifera by K. Chandrasenan and colleagues in 1965, who proposed a biphenylquinone structure for it. Later, during research on chiodectonic acid, Wolfgang Steglich noticed that this pigment shared the same Rf value in thin-layer chromatography (TLC) as chiodectonic acid from Chiodecton sanguineum. Though initial investigation was limited by the small amount of lichen material available, subsequent analysis of a larger quantity of P. coccifera confirmed that "pyxiferin" was actually identical to chiodectonic acid. Since chiodectonic acid had been previously described by Oswald Hesse in 1904, this name takes precedence. Further analysis showed that the compound from both lichens had the molecular formula C15H10O8, contradicting the C13H8O8 formula that Chandrasenan et al. had reported for pyxiferin.
Properties
Chiodectonic acid is a member of the class of chemical compounds called anthraquinones. Specifically, it is a naphthoquinone derivative. Its IUPAC name is 2-acetyl-3,5,6,8-tetrahydroxy-7-methoxybenzo[f][1]benzofuran-4,9-dione. The ultraviolet absorbance maxima (λmax) has three peaks at 287, 510, and 538 nm. In the infrared spectrum, peaks occur at 736, 800, 816, 828, 854, 944, 970, 1008, 1042, 1076, 1120, 1176, 1290, 1410, 1456, 1534, 1590, 1624, 1658, 3000, and 3340 cm−1. Chiodectonic acid's molecular formula is C15H10O8; it has a molecular mass of
334.23 grams per mole. In its purified form, it exists as dark red rhombic plates with a melting point of .
References
Lichen products
Naphthoquinones
Acetyl compounds
Naphthofurans | Chiodectonic acid | Chemistry | 495 |
57,410,053 | https://en.wikipedia.org/wiki/Proline%20isomerization%20in%20epigenetics | In epigenetics, proline isomerization is the effect that cis-trans isomerization of the amino acid proline has on the regulation of gene expression. Similar to aspartic acid, the amino acid proline has the rare property of being able to occupy both cis and trans isomers of its prolyl peptide bonds with ease. Peptidyl-prolyl isomerase, or PPIase, is an enzyme very commonly associated with proline isomerization due to their ability to catalyze the isomerization of prolines. PPIases are present in three types: cyclophilins, FK507-binding proteins, and the parvulins. PPIase enzymes catalyze the transition of proline between cis and trans isomers and are essential to the numerous biological functions controlled and affected by prolyl isomerization (i.e. cell signalling, protein folding, and epigenetic modifications) Without PPIases, prolyl peptide bonds will slowly switch between cis and trans isomers, a process that can lock proteins in a nonnative structure that can affect render the protein temporarily ineffective. Although this switch can occur on its own, PPIases are responsible for most isomerization of prolyl peptide bonds. The specific amino acid that precedes the prolyl peptide bond also can have an effect on which conformation the bond assumes. For instance, when an aromatic amino acid is bonded to a proline the bond is more favorable to the cis conformation. Cyclophilin A uses an "electrostatic handle" to pull proline into cis and trans formations. Most of these biological functions are affected by the isomerization of proline when one isomer interacts differently than the other, commonly causing an activation/deactivation relationship. As an amino acid, proline is present in many proteins. This aids in the multitude of effects that isomerization of proline can have in different biological mechanisms and functions.
Cell signaling
Cell signaling involves many different processes and proteins. One of the most studied cell signaling phenomena involving proline is the interactions with p53 and prolyl isomerases, specifically Pin1. The protein p53, along with p63 and p73, are responsible for ensuring that alterations to the genome are corrected and for preventing the formation and growth of tumors. proline residues are found throughout the p53 proteins and without the phosphorylation and isomerization of specific Serine/Threonine-Proline motifs within p53, they cannot exhibit control over their target genes. The main signalling processes that are affected by p53 are apoptosis and cell cycle arrest, both of which are controlled by specific isomerization of the prolines in p53.
History and discovery
Although isomerization of proteins has been known about since 1968 when it was discovered by C. Tanford, proline isomerization and its use as a noncovalent histone tail modification was not discovered until 2006 by Nelson and his colleagues.
As a histone tail modification
One of the most well known epigenetic mechanisms that proline isomerization plays a role in is the modification of histone tails, specifically those of histone H3. Fpr4 is a PPIase, in the FK507BP group, that exhibits catalytic activity at the proline positions 16, 30, and 38 (also written P16, P30, and P38 respectively) on the N-terminal region of histone H3 in Saccharomyces cerevisiae. Fpr4's binding affinity is strongest at the P38 site, followed by P30 and then P16. However the catalytic efficiency, or the increase in isomerization rates, is highest at P16 and P30 equally, followed by P38 which exhibits a very small change in isomerization rates with the binding of Fpr4. Histone H3 has an important lysine residue at the 36 position (also written K36) on the N-terminal tail which can be methylated by Set2, a methyltransferase. Methylation of K36 is key to normal transcription elongation. Due to P38's proximity to K36, cross-talk between P38 isomerization and K36 methylation can occur. This means that isomer changes at the P38 position can affect methylation at the K36 position. In the cis position, P38 shifts the histone tail closer to the DNA, crowding the area around the tail. This can cause a decrease the ability of proteins to bind to the DNA and to the histone tail, including preventing Set2 from methylating K36. Also, this tail movement can increase the number interactions between the histone tail and the DNA, increasing likelihood of nucleosome formation and potentially leading to the creation of higher-order chromatin structure. In trans, P38 leads to the opposite effects: allowing for Set2 to methylate K36. Set2 is only affected by isomerization of P38 when creating a trimethylated K36 (commonly written as K36me3), however, and not K36me2. Fpr4 also binds to P32 in H4, though its effects are minimal.
In mammalian cells, the isomerization of H3P30 interacts with the phosphorylation of H3S28 (serine in the 28 position of histone H3) and the methylation of H3K27. hFKBP25 is a PPIase that is a homolog for Fpr4 in mammalian cells and is found to commonly be associated with the presence of HDACs. Cyp33 is a cyclophilin that has the ability to isomerize H3 proline residues at P16 and P30 positions. Histones H2A and H2B also have multiple proline residues near amino acids that when modified affect the activity surrounding the histone.
Interactions with H3K4me3 and H3K14ac
The isomerization of the peptide bond between histone H3's alanine 15 and proline 16 is affected by the acetylation at K14 and can control the methylation states of K4. K4me3 represses gene transcription and depends upon the Set1 methyltransferase complex subunit Spp1 being balanced with the Jhd2 demethylases for proper function. Acetylation of K14 allows for a state change in P16 and primarily promotes the trans state of P16. This trans isomer of P16 reduces K4 methylation, which results in transcription repression. Isomerization of P16 has downstream effects of controlling protein binding to acetylated K18. When P16 is in the trans conformation, Spt7 is allowed to bind to K18ac, increasing transcription.
Interactions with gene regulatory proteins
RNA polymerase II
Proline isomerization of certain prolines in RNA polymerase II is key in the process of recruiting and placing processing factors during transcription. PPIases target RNA polymerase II by interacting with the Rpb1 carboxy terminal domain, or CTD. Proline isomerization is then used as part of the mechanism of the CTD to recruit co-factors required for co-transcriptional RNA processing, regulating RNA polymerase II activity. Nrd1 is a protein that is responsible for many of the transcriptional activities of RNAP II, specifically through the Nrd1- dependent termination pathway. This pathway requires the parvulin Ess1, or Pin1 depending on the organism, to isomerize the pSer5-Pro6 bond in the CTD. Without the cis conformation of the pSer5-Pro6 bond, created by Ess1/Pin1, Nrd1 cannot bind to RNAP II. Any variation from this process leads to a decrease in Nrd1 binding affinity, lowering the ability of RNAP II to process and degrade noncoding RNAs.
MLL1
Cyp33 in mammals causes isomerization in MLL1. MLL1 is a multiprotein complex that regulates gene expression and chromosomal translocations involving this gene often lead to leukemia. MLL's target genes include HOXC8, HOXA9, CDKN1B, and C-MYC. MLL also has two binding domains: a Cyp33 RNA-recognition motif domain (RRM), and a PHD3 domain that binds to H3K4me3 or Cyp33 RRM. Cyp33 has the ability to downregulate the expression of these genes through proline isomerization at the peptide bond between His1628 and Pro1629 within MLL. This bond lies in a sequence between the PHD3 finger of MLL1 and the bromeodomain of MLL1, and its isomerization mediates the bonding of the PHD3 domain and the Cyp33 RRM domain. When these two domains are bonded transcription is repressed through recruitment of histone deacetylases to MLL1 and inhibition of H3K4me3.
Phosphatase recruitment
Phosphorylated amino acids are crucial for the modulation of the binding of transcription factors and other gene regulatory proteins. Pin1's effect on isomerization of proline residues leads to an increase or decrease in recruitment of phosphatases, namely Scp1 and Ssu72 and their recruitment to the RNAP II CTD. The cis-Pro formation is associated with an increase in Ssu72. Scp1 on recognizes trans-Pro formations, and is not affected by such isomerization. Pin1 also triggers the activation of the DSIF complex and NELF, which are responsible for pausing RNAP II in mammalian cells, and their conversion into positive elongation factors, facilitating elongation. This potentially could be an isomerization dependent process.
Regulation of mRNA stability
Pin1, a parvulin, regulates mRNA stability and expression in certain eukaryotics mRNAs. These mRNAs are GM-CSF, Pth, and TGFβ and each of them have AREs, or AU-rich cis-elements. The ARE binding protein KSRP has a Pin1 binding site. Pin1 binds to this site and dephosphorylates the serine and isomerizes the peptide bond between Ser181 and Pro182. This isomerization causes the decay of Pth mRNA. KSRP, and other ARE binding proteins like AUF1, are thought to affect the other mRNAs through mechanisms similar to Pth, with the requirement of a phosphorylated serine bonded to a proline in a specific conformation. Pin1 also triggers proline isomerization of Stem-Loop Binding Protein (SLBP), allowing it to control the dissociation of SLBP from histone mRNA. This leads to Pin1 being able to affect histone mRNA decay. Pin1 affects many other genes in the form of gene silencing through the disruption of cell pathways, making it important in mRNA turnover by modulating RNA binding protein activity.
Difficulties with research
Currently there are no existing compounds that can mimic the peptide bond of proline to other amino acids while maintaining only a cis or trans configuration because most mimics found will eventually change from one isomer to another. This makes research on the direct effect of each of the isomers on biological mechanisms more difficult. Also, the actual isomerization of proline is a slow process, meaning that any studying of the effects of the different isomers of proline takes a large amount of time to complete.
References
Epigenetics
Gene expression
Glucogenic amino acids
Isomerism
Stereochemistry | Proline isomerization in epigenetics | Physics,Chemistry,Biology | 2,438 |
1,481,059 | https://en.wikipedia.org/wiki/Sesamex | Sesamex, also called sesoxane, is an organic compound used as an adjuvant for synergy; that is, it enhances the potency of pesticides such pyrethrins and pyrethroids, but is itself not a pesticide.
Solubility
Sesamex is soluble in kerosene, freon 11, and freon 12.
References
Insecticides
Benzodioxoles
Phenol ethers | Sesamex | Chemistry | 92 |
50,398,478 | https://en.wikipedia.org/wiki/Selection%20principle | In mathematics, a selection principle is a rule asserting
the possibility of obtaining mathematically significant objects by
selecting elements from given sequences of sets. The theory of selection principles
studies these principles and their relations to other mathematical properties.
Selection principles mainly describe covering properties,
measure- and category-theoretic properties, and local properties in
topological spaces, especially function spaces. Often, the
characterization of a mathematical property using a selection
principle is a nontrivial task leading to new insights on the
characterized property.
The main selection principles
In 1924, Karl Menger
introduced the following basis property for metric spaces:
Every basis of the topology contains a sequence of sets with vanishing
diameters that covers the space. Soon thereafter,
Witold Hurewicz
observed that Menger's basis property is equivalent to the
following selective property: for every sequence of open covers of the space,
one can select finitely many open sets from each cover in the sequence, such that the family of all selected sets covers the space.
Topological spaces having this covering property are called Menger spaces.
Hurewicz's reformulation of Menger's property was the first important
topological property described by a selection principle.
Let and be classes of mathematical objects.
In 1996, Marion Scheepers
introduced the following selection hypotheses,
capturing a large number of classic mathematical properties:
: For every sequence of elements from the class , there are elements such that .
: For every sequence of elements from the class , there are finite subsets such that .
In the case where the classes and consist of covers of some ambient space, Scheepers also introduced the following selection principle.
: For every sequence of elements from the class , none containing a finite subcover, there are finite subsets such that .
Later, Boaz Tsaban identified the prevalence of the following related principle:
: Every member of the class includes a member of the class .
The notions thus defined are selection principles. An instantiation of a selection principle, by considering specific classes and , gives a selection (or: selective) property. However, these terminologies are used interchangeably in the literature.
Variations
For a set and a family of subsets of , the star of in is the set .
In 1999, Ljubisa D.R. Kocinac introduced the following star selection principles:
: For every sequence of elements from the class , there are elements such that .
: For every sequence of elements from the class , there are finite subsets such that .
The star selection principles are special cases of the general selection principles. This can be seen by modifying the definition of the family accordingly.
Covering properties
Covering properties form the kernel of the theory of selection principles. Selection properties that are not covering properties are often studied by using implications to and from selective covering properties of related spaces.
Let be a topological space. An open cover of is a family of open sets whose union is the entire space For technical reasons, we also request that the entire space is not a member of the cover. The class of open covers of the space is denoted by . (Formally, , but usually the space is fixed in the background.) The above-mentioned property of Menger is, thus, . In 1942, Fritz Rothberger considered Borel's strong measure zero sets, and introduced a topological variation later called Rothberger space (also known as C space). In the notation of selections, Rothberger's property is the property .
An open cover of is point-cofinite if it has infinitely many elements, and every point belongs to all but finitely many sets . (This type of cover was considered by Gerlits and Nagy, in the third item of a certain list in their paper. The list was enumerated by Greek letters, and thus these covers are often called -covers.) The class of point-cofinite open covers of is denoted by . A topological space is a Hurewicz space if it satisfies .
An open cover of is an -cover if every finite subset of is contained in some member of . The class of -covers of is denoted by . A topological space is a γ-space if it satisfies .
By using star selection hypotheses one obtains properties such as star-Menger (), star-Rothberger () and star-Hurewicz ().
The Scheepers Diagram
There are 36 selection properties of the form , for and . Some of them are trivial (hold for all spaces, or fail for all spaces). Restricting attention to Lindelöf spaces, the diagram below, known as the Scheepers Diagram, presents nontrivial selection properties of the above form, and every nontrivial selection property is equivalent to one in the diagram. Arrows denote implications.
Local properties
Selection principles also capture important local properties.
Let be a topological space, and . The class of sets in the space that have the point in their closure is denoted by . The class consists of the countable elements of the class . The class of sequences in that converge to is denoted by .
A space is Fréchet–Urysohn if and only if it satisfies for all points .
A space is strongly Fréchet–Urysohn if and only if it satisfies for all points .
A space has countable tightness if and only if it satisfies for all points .
A space has countable fan tightness if and only if it satisfies for all points .
A space has countable strong fan tightness if and only if it satisfies for all points .
Topological games
There are close connections between selection principles and topological games.
The Menger game
Let be a topological space. The Menger game played on is a game for two players, Alice and Bob. It has an inning per each natural number . At the inning, Alice chooses an open cover of ,
and Bob chooses a finite subset of .
If the family is a cover of the space , then Bob wins the game. Otherwise, Alice wins.
A strategy for a player is a function determining the move of the player, given the earlier moves of both players. A strategy for a player is a winning strategy if each play where this player sticks to this strategy is won by this player.
A topological space is if and only if Alice has no winning strategy in the game played on this space.
Let be a metric space. Bob has a winning strategy in the game played on the space if and only if the space is -compact.
Note that among Lindelöf spaces, metrizable is equivalent to regular and second-countable, and so the previous result may alternatively be obtained by considering limited information strategies. A Markov strategy is one that only uses the most recent move of the opponent and the current round number.
Let be a regular space. Bob has a winning Markov strategy in the game played on the space if and only if the space is -compact.
Let be a second-countable space. Bob has a winning Markov strategy in the game played on the space if and only if he has a winning perfect-information strategy.
In a similar way, we define games for other selection principles from the given Scheepers Diagram. In all these cases a topological space has a property from the Scheepers Diagram if and only if Alice has no winning strategy in the corresponding game. But this does not hold in general:
Let be the family of k-covers of a space. That is, such that every compact set in the space is covered by some member of the cover.
Francis Jordan demonstrated a space where the selection principle holds, but
Alice has a winning strategy for the game
Examples and properties
Every space is a Lindelöf space.
Every σ-compact space (a countable union of compact spaces) is .
.
.
Assuming the Continuum Hypothesis, there are sets of real numbers witnessing that the above implications cannot be reversed.
Every Luzin set is but no .
Every Sierpiński set is Hurewicz.
Subsets of the real line (with the induced subspace topology) holding selection principle properties, most notably Menger and Hurewicz spaces, can be characterized by their continuous images in the Baire space . For functions , write if for all but finitely many natural numbers . Let be a subset of . The set is bounded if there is a function such that for all functions . The set is dominating if for each function there is a function such that .
A subset of the real line is if and only if every continuous image of that space into the Baire space is not dominating.
A subset of the real line is if and only if every continuous image of that space into the Baire space is bounded.
Connections with other fields
General topology
Every space is a D-space.
Let P be a property of spaces. A space is productively P if, for each space with property P, the product space has property P.
Every separable productively paracompact space is .
Assuming the Continuum Hypothesis, every productively Lindelöf space is productively
Let be a subset of the real line, and be a meager subset of the real line. Then the set is meager.
Measure theory
Every subset of the real line is a strong measure zero set.
Function spaces
Let be a Tychonoff space, and be the space of continuous functions with pointwise convergence topology.
satisfies if and only if is Fréchet–Urysohn if and only if is strong Fréchet–Urysohn.
satisfies if and only if has countable strong fan tightness.
satisfies if and only if has countable fan tightness.
See also
Compact space
Sigma-compact
Menger space
Hurewicz space
Rothberger space
References
Properties of topological spaces
Topology | Selection principle | Physics,Mathematics | 1,987 |
38,214,495 | https://en.wikipedia.org/wiki/Organic%20Geochemistry | Organic Geochemistry is a monthly peer-reviewed scientific journal published by Elsevier covering research on all aspects of organic geochemistry. It is an official journal of the European Association of Organic Geochemists. The editors-in-chief are Bart van Dongen (University of Manchester), Elizabeth Minor (University of Minnesota Duluth), and Clifford Walters (University of Texas at Austin).
Abstracting and indexing
The journal is abstracted and indexed in:
According to the Journal Citation Reports, the journal has a 2023 impact factor of 2.6.
Notable articles
According to the Web of Science, the journal's two most cited papers () are:
(cited 766 times)
(cited 722 times)
References
External links
European Association of Organic Geochemists
Monthly journals
Academic journals established in 1977
English-language journals
Geochemistry journals
Elsevier academic journals | Organic Geochemistry | Chemistry | 177 |
25,665,804 | https://en.wikipedia.org/wiki/C22H30O5 | The molecular formula C22H30O5 (molar mass: 374.47 g/mol, exact mass: 374.2093 u) may refer to:
Etiprednol
Guanacastepene A
Jasmolin II
Methylprednisolone
Nandrolone hydrogen succinate, or nandrolone hemisuccinate
Molecular formulas | C22H30O5 | Physics,Chemistry | 78 |
29,401,709 | https://en.wikipedia.org/wiki/Lucas%2014CUX | The Lucas 14CUX (sometimes referred to as the Rover 14CUX) is an automotive electronic fuel injection system developed by Lucas Industries and fitted to the Rover V8 engine in Land Rover vehicles between 1990 and 1995. The system was also paired with the Rover V8 by a number of low-volume manufacturers such as TVR, Marcos, Ginetta, and Morgan.
The system is also sometimes referred to as the "Rover Hot-Wire" or "Hitachi Hot-Wire", in reference to the style of airflow sensor it uses (and the sensor's manufacturer, Hitachi).
History
In the mid-1980s, Lucas developed the 13CU system by revising the Bosch L-Jetronic system and adding an electronic diagnostics capability to comply with California Air Resources Board requirements. The design of the 13CU also deviated from the original L-Jetronic design in that it used a hot-wire air mass sensor rather than the Jetronic's mechanical flap sensor.
The 13CU was further developed into the 14CU, which had (among other changes) an ECU that was more physically compact. The 14CU was used in US-market Range Rovers in 1989. Both the 13CU and 14CU were designed for use with only the 3.5L version of the Rover V8.
The 14CUX was the final iteration of the system, and featured upgraded injectors and (for some markets) an external diagnostic display. It also introduced the use of a "tune resistor", which is an external resistor that plugs into the harness and is sensed by the ECU to select one of five different sets of fueling data.
Hardware
The engine control unit (ECU) of the 14CUX system is run by a Motorola MC6803U4 8-bit microprocessor, which is an uncommon variant of the otherwise ubiquitous 6803. The processor is mislabelled in the ECU, possibly to deter any reverse engineering efforts. The 14CUX determines fueling values for each bank of the V8 separately, which requires the use of two dedicated timer outputs for independent control of the fuel injectors. This requirement helped to drive the selection of the MC6803U4 part, which has three timer outputs available (in contrast to the single timer output on the standard 6803.)
Minor design updates were made to the ECU through its life, with the earlier units given the part-number prefix "PRC" and the later units "AMR".
The code and data used by the microprocessor is stored in either a 27C128 or 27C256 EPROM (depending on the revision of the ECU), which is soldered in place on most PRC units and socketed in some late PRC units as well as AMR units. Only half of the 32KB PROM space is used, so the code/data image appears twice, duplicated in the upper half.
Function
In contrast to more modern engine management systems, the 14CUX controls fuel delivery only; it does not control spark ignition. On 14CUX-equipped vehicles, the spark control is done mechanically with the use of a distributor.
When the ignition is first turned on, the ECU energizes a relay that runs the fuel pump for a short time to pressurize the fuel rail. Once the starter motor begins to turn the engine, the ECU gets a 12VDC signal that causes it to run the fuel pump again, and energize the fuel injectors. For the next several seconds, the injector pulse width is wider than normal to provide sufficient fuel for starting. Idle control is performed by adjusting a stepper-motor-driven bypass valve in the intake plenum. When the ignition is switched off, the ECU winds the bypass valve fully open to provide enough air the next time the engine is started.
To determine the amount of fuel required by the engine, the ECU reads a number of sensors measuring the following factors:
Intake air mass
Coolant temperature
Engine speed
Throttle position
Fuel temperature
Exhaust oxygen content (narrowband)
Road speed
The intake air mass is measured with a "hot-wire" mass airflow sensor: drawn in by intake manifold vacuum, air moves past an electrically heated wire filament, and the degree to which the filament is cooled indicates the mass of the airstream.
Two factors (crankshaft speed and engine load) are used to index into a two-dimensional matrix of numeric values known as the "fuel map". The value read from the map is offset by other environmental factors (such as coolant temperature). This corrected value is then used to meter fuel by pulse-width modulating the fuel injectors. Because each bank of the V8 feeds an exhaust line with its own oxygen sensor, the air/fuel ratio can be monitored and controlled for the banks independently.
The 14CUX PROM may contain up to five fuel maps, which allowed a single ROM image to contain maps for multiple target markets. In some markets, the active map is selectable by placing an external tune resistor on a particular pin of the ECU. This external map selection was disabled in the code for North American specification (NAS) vehicles.
Open loop
Above a certain engine speed or throttle position, the ECU switches to "open-loop" mode; the inputs from the exhaust lambda sensors are ignored and the mixture is enriched beyond stoichiometric for higher power and decreased engine wear.
In addition to engine speed and load conditions triggering open-loop mode, the selection of the fuel map also may force this mode. For certain fuel maps, the 14CUX firmware fuels in open-loop mode under all running conditions.
Diagnostics
The design of the 14CUX was done well in advance of the requirement (for the 1996 model year) that all passenger vehicles sold in the United States support OBD-II. As a result, the diagnostics information collected by the 14CUX is not accessible via an OBD-II-compliant interface. In lieu of an industry-standard diagnostic interface, the 14CUX is able to communicate over a serial link at non-standard voltage levels and baud rate. The reference clock for the UART runs at 1 MHz and the clock divisor is set to 128, which produces a data rate of 7812.5 baud. The serial interface allows reading and writing arbitrary memory locations via a simple software protocol. Because the value from a given sensor is always stored at the same location in RAM, these sensor values can be read if the memory location is known.
The 14CUX is capable of storing diagnostic trouble codes in a 32-byte segment of its internal memory that is maintained (even while vehicle ignition is off) by applying 5VDC (regulated down from 12VDC from the vehicle's battery.) Because of this maintainer voltage, the ECU is always drawing a small amount of current. Fault codes can be cleared by disconnecting the battery for a short period of time. Diagnostic trouble codes can be retrieved from the ECU via a small electronic display referred to as the "Fault Code Display Unit". This unit contains two seven-segment displays that together show a single two-digit fault code. When connected to the 14CUX wiring harness, the ECU detects its presence and reconfigures the RDATA and TDATA lines to work as an I2C link to this device.
Applications
In addition to the Land Rover Discovery, Defender, and Range Rover, the 14CUX was used with the Rover V8 in the TVR Griffith and its sister car, the Chimaera. In the TVR applications, engines as large as 5.0L were offered; these larger displacements required the development of new fuel maps for the engine to run properly.
Between 1990 and 1993, Ginetta produced the G33 roadster, which used the 3.9L Rover V8 and 14CUX.
For model year 1996, Land Rover chose to discontinue use of the 14CUX in its products and instead used GEMS ("Generic Engine Management System"), which had been developed jointly by Lucas and SAGEM. This was done in part due to the requirement for OBD-II in the United States market. Some automakers whose products were not exported to North America (such as TVR) continued to use the 14CUX until the later discontinuation of the Rover V8 engine.
Main connector pin assignments
The ECU interfaces with the rest of the system via a 40-pin connector. When observing the connector on the ECU box itself, with the thumb latch on the left, the numbering for the connector's pins starts at 1 in the lower left-hand corner. The pin numbering continues to the right, then in an S-shape through the two other pin rows.
References
External links
Reverse-engineered 14CUX ECU and serial port information
Ginetta G33 Fuel Injection System (www.g33.co.uk)
Fuel injection systems
Engine components | Lucas 14CUX | Technology | 1,851 |
55,092,950 | https://en.wikipedia.org/wiki/Mycoacia%20rubiginosa | Mycoacia rubiginosa is a species of toothed crust fungus in the family Meruliaceae. It was described as a new species in 2004 by mycologists Kurt Hjortstam and Leif Ryvarden. The type collection was made in Sierra Nevada de Santa Marta, in Magdalena, Colombia, where the fungus was found growing on dead hardwood. It is known only from the type locality. Fruit bodies of M. rubiginosa are distinguished by their reddish colour, and spines up to long. The hyphal system is monomitic, containing only generative hyphae. The spores are ellipsoid, smooth, thin-walled and translucent, with dimensions of 4–4.5 by 2.5–2.75 μm.
References
Meruliaceae
Fungi of Colombia
Sierra Nevada de Santa Marta
Fungi described in 2004
Taxa named by Leif Ryvarden
Fungus species | Mycoacia rubiginosa | Biology | 188 |
965,259 | https://en.wikipedia.org/wiki/Cable%20modem%20termination%20system | A cable modem termination system (CMTS, also called a CMTS Edge Router) is a piece of equipment, typically located in a cable company's headend or hubsite, which is used to provide data services, such as cable Internet or Voice over IP, to cable subscribers.
A CMTS provides similar functions to a DSLAM in a digital subscriber line or an optical line termination in a passive optical network.
Connections
In order to provide high speed data services, a cable company will connect its headend to the Internet via very high capacity data links to a network service provider. On the subscriber side of the headend, the CMTS enables communication with subscribers' cable modems. Different CMTSs are capable of serving different cable modem population sizes—ranging from 4,000 cable modems to 150,000 or more, depending in part on traffic, although it is recommended for an I-CMTS to service, for example, 30,000 subscribers (cable modems). A given headend may have between 1–12 CMTSs to service the cable modem population served by that headend or HFC hub.
One way to think of a CMTS is to imagine a router with Ethernet interfaces (connections) on one side and coaxial cable RF interfaces on the other side. The Ethernet side is known as the Network Side Interface or NSI.
A service group is a group of customers that share communication channels and thus bandwidth. A CMTS has separate RF interfaces and connectors for downlink and uplink signals. The RF/coax interfaces carry RF signals to and from coaxial "trunks" connected to subscribers' cable modems, using one pair of connectors per trunk, one for downlink and the other for uplink. In other words, there can be a pair of RF connectors for every service group, although it is possible to configure a network with different numbers of connectors that service a set of service groups, based on the number of downstream and upstream channels the cable modems in every service group use. Every connector has a finite number of channels it can carry, such as 16 channels per downstream connector, and 4 channels per upstream connector, depending on the CMTS. For example, if the cable modems on every service group use 24 channels for downstream, and 2 channels for upstream, then 3 downstream connectors can service the cable modems on two service groups, and be serviced by 1 upstream connector. A service group may serve up to 500 households. A service group has channels, whose bandwidth is shared among all members of the service group. The channels are later regrouped at the cable headend or distribution hub and serviced by CMTSs and other equipment such as Edge QAMs.
The RF signals from a CMTS, are connected via coaxial cable to headend RF management modules for RF splitting and combining, with other equipment such as other CMTSs so that several CMTS can service one service group, and then to an "optics platform" or headend platform, which has transmitter and receiver modules that turn the RF signals into light pulses for delivery over fiber optics through an HFC network. Examples of optics platforms are the Arris CH3000 and Cisco Prisma II. At the other end of the network, an optical node converts the light pulses into RF signals again and sends them through a coaxial cable "trunk". The trunk has one or more amplifiers along its length, and on the trunk there are distribution "taps" to which customers' modems are connected via coaxial cable.
In fact, most CMTSs have both Ethernet interfaces (or other more traditional high-speed data interfaces like SONET) as well as RF interfaces. In this way, traffic that is coming from the Internet can be routed (or bridged) through the Ethernet interface, through the CMTS and then onto the RF interfaces that are connected to the cable company's hybrid fiber coax (HFC). The traffic winds its way through the HFC to end up at the cable modem in the subscriber's home. Traffic from a subscriber's home system goes through the cable modem and out to the Internet in the opposite direction.
CMTSs typically carry only IP traffic. Traffic destined for the cable modem from the Internet, known as downstream traffic, is carried in IP packets encapsulated according to DOCSIS standard. These packets are carried on data streams that are typically modulated onto a TV channel using either 64-QAM or 256-QAM versions of quadrature amplitude modulation.
Upstream data (data from cable modems to the headend or Internet) is carried in Ethernet frames encapsulated inside DOCSIS frames modulated with QPSK, 16-QAM, 32-QAM, 64-QAM or 128-QAM using TDMA, ATDMA or S-CDMA frequency sharing mechanisms. This is usually done at the "subband" or "return" portion of the cable TV spectrum (also known as the "T" channels), a much lower part of the frequency spectrum than the downstream signal, usually 5–42 MHz in DOCSIS 2.0 or 5–65 MHz in EuroDOCSIS.
A typical CMTS allows a subscriber's computer to obtain an IP address by forwarding DHCP requests to the relevant servers. This DHCP server returns, for the most part, what looks like a typical response including an assigned IP address for the computer, gateway/router addresses to use, DNS servers, etc.
The CMTS may also implement some basic filtering to protect against unauthorized users and various attacks. Traffic shaping is sometimes performed to prioritize application traffic, perhaps based upon subscribed plan or download usage and also to provide guaranteed Quality of service (QoS) for the cable operator's own PacketCable-based VOIP service. However, the function of traffic shaping is more likely done by a Cable Modem or policy traffic switch. A CMTS may also act as a bridge or router.
A customer's cable modem cannot communicate directly with other modems on the line. In general, cable modem traffic is routed to other cable modems or to the Internet through a series of CMTSs and traditional routers. However, a route could conceivably pass through a single CMTS.
A CCAP (Converged Cable Access Platform) combines CMTS and Edge QAM functionality in a single device so that it can provide both data (internet) with CMTS functionality, and video (TV channels) with Edge QAM functionality. Edge QAM (Quadrature Amplitude Modulator/Modulation) converts video sent via IP (internet protocol) or otherwise, into a QAM signal for delivery over a cable network. Edge QAMs are normally standalone devices placed at the "edge" of a network. They can also be connected to a CMTS core, to make up an M-CMTS system which is more scalable. A CMTS core is normally a conventional or I-CMTS that supports operation as a CMTS core in an M-CMTS system.
Architectures
A CMTS can be broken down into several different architectures, Integrated CMTS (I-CMTS), Modular (M-CMTS), Virtual CMTS (vCMTS) and remote CMTS. An I-CMTS incorporates into a single unit all components necessary for its operation. There are both pros and cons to each type of architecture.
Modular CMTS (M-CMTS)
In a M-CMTS solution the architecture of an I-CMTS is broken up into two components. The first part is the Physical Downstream component (PHY) which is known as the Edge QAM (EQAM). The second part is the IP networking and DOCSIS MAC Component which is referred to as the M-CMTS Core. There are also several new protocols and components introduced with this type of architecture. One is the DOCSIS Timing Interface, which provides a reference frequency between the EQAM and M-CMTS Core via a DTI Server. The second is the Downstream External PHY Interface (DEPI). The DEPI protocol controls the delivery of DOCSIS
frames from the M-CMTS Core to the EQAM devices Some of the challenges that entail an M-CMTS platform are increased complexity in RF combining and an increase in the number of failure points. One of the benefits of an M-CMTS architecture is that it is extremely scalable to larger numbers of downstream channels.
Virtual CMTS
Virtual CCAPs (vCCAPs) or virtual CMTSs (vCMTSs) are implemented on commercial off the shelf x86-based servers with specialized software, and can be used to increase service capacity without purchasing new CMTS/CCAP chassis, or add features to the CMTS/CCAP more quickly.
Remote CMTS
Remote CMTS/Remote CCAP moves all CMTS/CCAP functionality to the outside plant, in stark contrast to conventional CMTSs or CCAPs which are installed at a service provider location.
Manufacturers
Current
ARRIS Group
C9 Networks
Catapult Technologies
Coaxial Networks Inc.
Casa Systems
Cisco Systems
Chongqing Jinghong
Damery sa
Gainspeed (Nokia company)
WISI Communications GmbH
Kathrein
Suma Scientific
Huawei Technologies
Harmonic Inc.
Teleste
Historical
3COM (Acquired by HP)
Broadband Access Systems (Acquired by ADC Telecommunications)
ADC Telecommunications (CMTS business acquired by BigBand Networks)
BigBand Networks (Exited CMTS business, remaining business later acquired by ARRIS)
Cadant (Acquired by ARRIS)
Com21 (CMTS business acquired by ARRIS)
RiverDelta (Acquired by Motorola)
Terayon (Acquired by Motorola)
Pacific Broadband Communications (Acquired by Juniper Networks)
Juniper Networks (Exited CMTS business)
LanCity (Acquired by BayNetworks)
Motorola (Acquired by ARRIS)
Daphne sa (Acquired by Damery sa)
Scientific Atlanta (Acquired by Cisco)
See also
DOCSIS
References
External links
Digital cable
Internet access | Cable modem termination system | Technology | 2,080 |
185,046 | https://en.wikipedia.org/wiki/Summer%20Triangle | The Summer Triangle is an astronomical asterism in the northern celestial hemisphere. The defining vertices of this imaginary triangle are at Altair, Deneb, and Vega, each of which is the brightest star of its constellation (Aquila, Cygnus, and Lyra, respectively). The greatest declination is +45° and lowest is +9° meaning the three can be seen from all places in the Northern Hemisphere and from the home of most people resident in the Southern Hemisphere. The two stars in Aquila and Cygnus represent the head of an eagle and tail of a swan that looks east inscribed into the triangle and forming the altitude of the triangle. Two small constellations, Sagitta and Vulpecula, lie between Aquila in the south of the triangle and Cygnus and Lyra to the north.
History
The term was popularized by American author H. A. Rey and British astronomer Patrick Moore in the 1950s. The name can be found in constellation guidebooks as far back as 1913. The Austrian astronomer Oswald Thomas described these stars as Grosses Dreieck (Great Triangle) in the late 1920s and Sommerliches Dreieck (Summerly Triangle) in 1934. The asterism was remarked upon by Joseph Johann von Littrow, who described it as the "conspicuous triangle" in the text of his atlas (1866), and Johann Elert Bode connected the stars in a map in a book in 1816, although without label. These are the same stars recognized in the Chinese legend of The Cowherd and the Weaver Girl, a story dating back some 2,600 years, celebrated in the Qixi Festival. The stars also bear ceremonial significance in the related celebrations of Tanabata, Chilseok, and Thất Tịch, derived from Qixi. In the mid- to late-20th century, before inertial navigation systems and other electronic and mechanical equipment took their places in military aircraft, United States Air Force navigators referred to this asterism as the "Navigator's Triangle".
Visibility
From mid-to-tropical northern latitudes:
the centre of the triangle appears about overhead around solar midnight during summer, and exactly so at about the 27th parallel north. This means it rises at sunset in the east and sets at sunrise in the west.
it is visible in the eastern sky in early mornings during spring.
In autumn and winter evenings, it is visible in the western sky until January.
From mid-southern latitudes, the asterism is in the north during the culmination season described above.
The stars of the Summer Triangle
Both Altair and Vega are bluish-white, rapidly-rotating A-type main sequence stars in the local neighbourhood of the sun. However, Deneb is a white supergiant star over 100 times as distant, and one of the most luminous stars in the entire galaxy.
See also
Northern Cross
Spring Great Diamond
Spring Triangle
Winter Triangle
Winter Hexagon
Heavenly Market enclosure
References
External links
Summer Triangle at Basic Celestial Phenomena by Kerry Magruder
Summer Triangle at The Astronomy Net
Summer Triangle at DavidDarling.info
Asterisms (astronomy)
Vega | Summer Triangle | Astronomy | 644 |
27,430,123 | https://en.wikipedia.org/wiki/Integer%20triangle | An integer triangle or integral triangle is a triangle all of whose side lengths are integers. A rational triangle is one whose side lengths are rational numbers; any rational triangle can be rescaled by the lowest common denominator of the sides to obtain a similar integer triangle, so there is a close relationship between integer triangles and rational triangles.
Sometimes other definitions of the term rational triangle are used: Carmichael (1914) and Dickson (1920) use the term to mean a Heronian triangle (a triangle with integral or rational side lengths and area); Conway and Guy (1996) define a rational triangle as one with rational sides and rational angles measured in degrees—the only such triangles are rational-sided equilateral triangles.
General properties for an integer triangle
Integer triangles with given perimeter
Any triple of positive integers can serve as the side lengths of an integer triangle as long as it satisfies the triangle inequality: the longest side is shorter than the sum of the other two sides. Each such triple defines an integer triangle that is unique up to congruence. So the number of integer triangles (up to congruence) with perimeter p is the number of partitions of p into three positive parts that satisfy the triangle inequality. This is the integer closest to when p is even and to when p is odd. It also means that the number of integer triangles with even numbered perimeters is the same as the number of integer triangles with odd numbered perimeters Thus there is no integer triangle with perimeter 1, 2 or 4, one with perimeter 3, 5, 6 or 8, and two with perimeter 7 or 10. The sequence of the number of integer triangles with perimeter p, starting at is:
0, 0, 1, 0, 1, 1, 2, 1, 3, 2, 4, 3, 5, 4, 7, 5, 8, 7, 10, 8 ...
This is called Alcuin's sequence.
Integer triangles with given largest side
The number of integer triangles (up to congruence) with given largest side c and integer triple is the number of integer triples such that and This is the integer value Alternatively, for c even it is the double triangular number and for c odd it is the square It also means that the number of integer triangles with greatest side c exceeds the number of integer triangles with greatest side c − 2 by c. The sequence of the number of non-congruent integer triangles with largest side c, starting at c = 1, is:
1, 2, 4, 6, 9, 12, 16, 20, 25, 30, 36, 42, 49, 56, 64, 72, 81, 90 ...
The number of integer triangles (up to congruence) with given largest side c and integer triple (a, b, c) that lie on or within a semicircle of diameter c is the number of integer triples such that a + b > c , a2 + b2 ≤ c2 and a ≤ b ≤ c. This is also the number of integer sided obtuse or right (non-acute) triangles with largest side c. The sequence starting at c = 1, is:
0, 0, 1, 1, 3, 4, 5, 7, 10, 13, 15, 17, 22, 25, 30, 33, 38, 42, 48 ...
Consequently, the difference between the two above sequences gives the number of acute integer sided triangles (up to congruence) with given largest side c. The sequence starting at c = 1, is:
1, 2, 3, 5, 6, 8, 11, 13, 15, 17, 21, 25, 27, 31, 34, 39, 43, 48, 52 ...
Area of an integer triangle
By Heron's formula, if T is the area of a triangle whose sides have lengths a, b, and c then
Since all the terms under the radical on the right side of the formula are integers it follows that all integer triangles must have 16T2 an integer and T2 will be rational.
Angles of an integer triangle
By the law of cosines, every angle of an integer triangle has a rational cosine. Every angle of an integer right triangle also has rational sine (see Pythagorean triple).
If the angles of any triangle form an arithmetic progression then one of its angles must be 60°. For integer triangles the remaining angles must also have rational cosines and a method of generating such triangles is given below. However, apart from the trivial case of an equilateral triangle, there are no integer triangles whose angles form either a geometric or harmonic progression. This is because such angles have to be rational angles of the form with rational But all the angles of integer triangles must have rational cosines and this will occur only when i.e. the integer triangle is equilateral.
The square of each internal angle bisector of an integer triangle is rational, because the general triangle formula for the internal angle bisector of angle A is where s is the semiperimeter (and likewise for the other angles' bisectors).
Side split by an altitude
Any altitude dropped from a vertex onto an opposite side or its extension will split that side or its extension into rational lengths.
Medians
The square of twice any median of an integer triangle is an integer, because the general formula for the squared median ma2 to side a is , giving (2ma)2 = 2b2 + 2c2 − a2 (and likewise for the medians to the other sides).
Circumradius and inradius
Because the square of the area of an integer triangle is rational, the square of its circumradius is also rational, as is the square of the inradius.
The ratio of the inradius to the circumradius of an integer triangle is rational, equaling for semiperimeter s and area T.
The product of the inradius and the circumradius of an integer triangle is rational, equaling
Thus the squared distance between the incenter and the circumcenter of an integer triangle, given by Euler's theorem as is rational.
Heronian triangles
A Heronian triangle, also known as a Heron triangle or a Hero triangle, is a triangle with integer sides and integer area.
All Heronian triangles can be placed on a lattice with each vertex at a lattice point. Furthermore, if an integer triangle can be place on a lattice with each vertex at a lattice point it must be Heronian.
General formula
Every Heronian triangle has sides proportional to
for integers m, n and k subject to the constraints:
The proportionality factor is generally a rational where q = gcd(a,b,c) reduces the generated Heronian triangle to its primitive and scales up this primitive to the required size.
Pythagorean triangles
A Pythagorean triangle is right-angled and Heronian. Its three integer sides are known as a Pythagorean triple or Pythagorean triplet or Pythagorean triad. All Pythagorean triples with hypotenuse which are primitive (the sides having no common factor) can be generated by
where m and n are coprime integers and one of them is even with m > n.
Every even number greater than 2 can be the leg of a Pythagorean triangle (not necessarily primitive) because if the leg is given by and we choose as the other leg then the hypotenuse is . This is essentially the generation formula above with set to 1 and allowing to range from 2 to infinity.
Pythagorean triangles with integer altitude from the hypotenuse
There are no primitive Pythagorean triangles with integer altitude from the hypotenuse. This is because twice the area equals any base times the corresponding height: 2 times the area thus equals both ab and cd where d is the height from the hypotenuse c. The three side lengths of a primitive triangle are coprime, so is in fully reduced form; since c cannot equal 1 for any primitive Pythagorean triangle, d cannot be an integer.
However, any Pythagorean triangle with legs x, y and hypotenuse z can generate a Pythagorean triangle with an integer altitude, by scaling up the sides by the length of the hypotenuse z. If d is the altitude, then the generated Pythagorean triangle with integer altitude is given by
Consequently, all Pythagorean triangles with legs a and b, hypotenuse c, and integer altitude d from the hypotenuse, with , which necessarily satisfy both a2 + b2 = c2 and , are generated by
for coprime integers m, n with m > n.
Heronian triangles with sides in arithmetic progression
A triangle with integer sides and integer area has sides in arithmetic progression if and only if the sides are (b – d, b, b + d), where
and where g is the greatest common divisor of and
Heronian triangles with one angle equal to twice another
All Heronian triangles with B = 2A are generated by either
with integers k, s, r such that or
with integers such that and
No Heronian triangles with B = 2A are isosceles or right triangles because all resulting angle combinations generate angles with non-rational sines, giving a non-rational area or side.
Isosceles Heronian triangles
All isosceles Heronian triangles are decomposable. They are formed by joining two congruent Pythagorean triangles along either of their common legs such that the equal sides of the isosceles triangle are the hypotenuses of the Pythagorean triangles, and the base of the isosceles triangle is twice the other Pythagorean leg. Consequently, every Pythagorean triangle is the building block for two isosceles Heronian triangles since the join can be along either leg.
All pairs of isosceles Heronian triangles are given by rational multiples of
and
for coprime integers u and v with u > v and u + v odd.
Heronian triangles whose perimeter is four times a prime
It has been shown that a Heronian triangle whose perimeter is four times a prime is uniquely associated with the prime and that the prime is congruent to or modulo . It is well known that such a prime can be uniquely partitioned into integers and such that (see Euler's idoneal numbers). Furthermore, it has been shown that such Heronian triangles are primitive since the smallest side of the triangle has to be equal to the prime that is one quarter of its perimeter.
Consequently, all primitive Heronian triangles whose perimeter is four times a prime can be generated by
for integers and such that is a prime.
Furthermore, the factorization of the area is where is prime. However the area of a Heronian triangle is always divisible by . This gives the result that apart from when and which gives all other parings of and must have odd with only one of them divisible by .
Heronian triangles with rational angle bisectors
If in a Heronian triangle the angle bisector of the angle , the angle bisector of the angle and the angle bisector of the angle have a rational relationship with the three sides then not only but also , and must be Heronian angles. Namely, if both angles and are Heronian then , the complement of , must also be a Heronian angle, so that all three angle-bisectors are rational. This is also evident if one multiplies:
together. Namely, through this one obtains:
where denotes the semi-perimeter, and the area of the triangle.
All Heronian triangles with rational angle bisectors are generated by
where are such that
where are arbitrary integers such that
and coprime,
and coprime.
Heronian triangles with integer inradius and exradii
There are infinitely many decomposable, and infinitely many indecomposable, primitive Heronian (non-Pythagorean) triangles with integer radii for the incircle and each excircle. A family of decomposible ones is given by
and a family of indecomposable ones is given by
Heronian triangles as faces of a tetrahedron
There exist tetrahedra having integer-valued volume and Heron triangles as faces. One example has one edge of 896, the opposite edge of 190, and the other four edges of 1073; two faces have areas of 436800 and the other two have areas of 47120, while the volume is 62092800.
Heronian triangles in a 2D lattice
A 2D lattice is a regular array of isolated points where if any one point is chosen as the Cartesian origin (0, 0), then all the other points are at (x, y) where x and y range over all positive and negative integers. A lattice triangle is any triangle drawn within a 2D lattice such that all vertices lie on lattice points. By Pick's theorem a lattice triangle has a rational area that either is an integer or a half-integer (has a denominator of 2). If the lattice triangle has integer sides then it is Heronian with integer area.
Furthermore, it has been proved that all Heronian triangles can be drawn as lattice triangles. Consequently, an integer triangle is Heronian if and only if it can be drawn as a lattice triangle.
There are infinitely many primitive Heronian (non-Pythagorean) triangles which can be placed on an integer lattice with all vertices, the incenter, and all three excenters at lattice points. Two families of such triangles are the ones with parametrizations given above at #Heronian triangles with integer inradius and exradii.
Integer automedian triangles
An automedian triangle is one whose medians are in the same proportions (in the opposite order) as the sides. If x, y, and z are the three sides of a right triangle, sorted in increasing order by size, and if 2x < z, then z, x + y, and y − x are the three sides of an automedian triangle. For instance, the right triangle with side lengths 5, 12, and 13 can be used in this way to form the smallest non-trivial (i.e., non-equilateral) integer automedian triangle, with side lengths 13, 17, and 7.
Consequently, using Euclid's formula, which generates primitive Pythagorean triangles, it is possible to generate primitive integer automedian triangles as
with and coprime and odd, and (if the quantity inside the absolute value signs is negative) or (if that quantity is positive) to satisfy the triangle inequality.
An important characteristic of the automedian triangle is that the squares of its sides form an arithmetic progression. Specifically, so
Integer triangles with specific angle properties
Integer triangles with a rational angle bisector
A triangle family with integer sides and with rational bisector of angle A is given by
with integers .
Integer triangles with integer n-sectors of all angles
There exist infinitely many non-similar triangles in which the three sides and the bisectors of each of the three angles are integers.
There exist infinitely many non-similar triangles in which the three sides and the two trisectors of each of the three angles are integers.
However, for n > 3 there exist no triangles in which the three sides and the (n – 1) n-sectors of each of the three angles are integers.
Integer triangles with one angle with a given rational cosine
Integer triangles with one angle at vertex A having given rational cosine h / k (h < 0 or > 0; k > 0) are given by
where p and q are any coprime positive integers such that p > qk. All primitive solutions can be obtained by dividing a, b, and c by their greatest common divisor.
Integer triangles with a 60° angle (angles in arithmetic progression)
All integer triangles with a 60° angle have their angles in an arithmetic progression. All such triangles are proportional to:
with coprime integers m, n and 1 ≤ n ≤ m or 3m ≤ n. From here, all primitive solutions can be obtained by dividing a, b, and c by their greatest common divisor.
Integer triangles with a 60° angle can also be generated by
with coprime integers m, n with 0 < n < m (the angle of 60° is opposite to the side of length a). From here, all primitive solutions can be obtained by dividing a, b, and c by their greatest common divisor (e.g. an equilateral triangle solution is obtained by taking and , but this produces a = b = c = 3, which is not a primitive solution). See also
More precisely, If , then , otherwise . Two different pairs and generate the same triple. Unfortunately the two pairs can both have a gcd of 3, so we can't avoid duplicates by simply skipping that case. Instead, duplicates can be avoided by going only till . We still need to divide by 3 if the gcd is 3. The only solution for under the above constraints is for . With this additional constraint all triples can be generated uniquely.
An Eisenstein triple is a set of integers which are the lengths of the sides of a triangle where one of the angles is 60 degrees.
Integer triangles with a 120° angle
Integer triangles with a 120° angle can be generated by
with coprime integers m, n with 0 < n < m (the angle of 120° is opposite to the side of length a). From here, all primitive solutions can be obtained by dividing a, b, and c by their greatest common divisor. The smallest solution, for m = 2 and n = 1, is the triangle with sides (3,5,7). See also.
More precisely, If , then , otherwise . Since the biggest side a can only be generated with a single pair, each primitive triple can be generated in precisely two ways: once directly with a gcd of 1, and once indirectly with a gcd of 3. Therefore, in order to generate all primitive triples uniquely, one can just add additional condition.
Integer triangles with one angle equal to an arbitrary rational number times another angle
For positive coprime integers h and k, the triangle with the following sides has angles , , and and hence two angles in the ratio h : k, and its sides are integers:
where and p and q are any coprime integers such that .
Integer triangles with one angle equal to twice another
With angle A opposite side and angle B opposite side , some triangles with B = 2A are generated by
with integers m, n such that 0 < n < m < 2n.
All triangles with B = 2A (whether integer or not) satisfy
Integer triangles with one angle equal to 3/2 times another
The equivalence class of similar triangles with are generated by
with integers such that , where is the golden ratio .
All triangles with (whether with integer sides or not) satisfy
Integer triangles with one angle three times another
We can generate the full equivalence class of similar triangles that satisfy B = 3A by using the formulas
where and are integers such that .
All triangles with B = 3A (whether with integer sides or not) satisfy
Integer triangles with three rational angles
The only integer triangle with three rational angles (rational numbers of degrees, or equivalently rational fractions of a full turn) is the equilateral triangle. This is because integer sides imply three rational cosines by the law of cosines, and by Niven's theorem a rational cosine coincides with a rational angle if and only if the cosine equals 0, ±1/2, or ±1. The only ones of these giving an angle strictly between 0° and 180° are the cosine value 1/2 with the angle 60°, the cosine value –1/2 with the angle 120°, and the cosine value 0 with the angle 90°. The only combination of three of these, allowing multiple use of any of them and summing to 180°, is three 60° angles.
Integer triangles with integer ratio of circumradius to inradius
Conditions are known in terms of elliptic curves for an integer triangle to have an integer ratio N of the circumradius to the inradius. The smallest case, that of the equilateral triangle, has N = 2. In every known case, – that is, is divisible by 8.
5-Con triangle pairs
A 5-Con triangle pair is a pair of triangles that are similar but not congruent and that share three angles and two sidelengths. Primitive integer 5-Con triangles, in which the four distinct integer sides (two sides each appearing in both triangles, and one other side in each triangle) share no prime factor, have triples of sides
and
for positive coprime integers x and y. The smallest example is the pair (8, 12, 18), (12, 18, 27), generated by x = 2, y = 3.
Particular integer triangles
The only triangle with consecutive integers for sides and area has sides (3, 4, 5) and area 6.
The only triangle with consecutive integers for an altitude and the sides has sides (13, 14, 15) and altitude from side 14 equal to 12.
The (2, 3, 4) triangle and its multiples are the only triangles with integer sides in arithmetic progression and having the complementary exterior angle property. This property states that if angle C is obtuse and if a segment is dropped from B meeting perpendicularly AC extended at P, then ∠CAB=2∠CBP.
The (3, 4, 5) triangle and its multiples are the only integer right triangles having sides in arithmetic progression.
The (4, 5, 6) triangle and its multiples are the only triangles with one angle being twice another and having integer sides in arithmetic progression.
The (3, 5, 7) triangle and its multiples are the only triangles with a 120° angle and having integer sides in arithmetic progression.
The only integer triangle with area = semiperimeter has sides (3, 4, 5).
The only integer triangles with area = perimeter have sides (5, 12, 13), (6, 8, 10), (6, 25, 29), (7, 15, 20), and (9, 10, 17). Of these the first two, but not the last three, are right triangles.
There exist integer triangles with three rational medians. The smallest has sides (68, 85, 87). Others include (127, 131, 158), (113, 243, 290), (145, 207, 328) and (327, 386, 409).
There are no isosceles Pythagorean triangles.
The only primitive Pythagorean triangles for which the square of the perimeter equals an integer multiple of the area are (3, 4, 5) with perimeter 12 and area 6 and with the ratio of perimeter squared to area being 24; (5, 12, 13) with perimeter 30 and area 30 and with the ratio of perimeter squared to area being 30; and (9, 40, 41) with perimeter 90 and area 180 and with the ratio of perimeter squared to area being 45.
There exists a unique (up to similitude) pair of a rational right triangle and a rational isosceles triangle which have the same perimeter and the same area. The unique pair consists of the (377, 135, 352) triangle and the (366, 366, 132) triangle. There is no pair of such triangles if the triangles are also required to be primitive integral triangles. The authors stress the striking fact that the second assertion can be proved by an elementary argumentation (they do so in their appendix A), whilst the first assertion needs modern highly non-trivial mathematics.
See also
Brahmagupta triangle, a Heronian triangle in which the side lengths are consecutive integers
Robbins pentagon, a cyclic pentagon with integer sides and integer area
Euler brick, a cuboid with integer edges and integer face diagonals
References
Arithmetic problems of plane geometry
Discrete geometry
Squares in number theory
Types of triangles | Integer triangle | Mathematics | 5,045 |
12,929,900 | https://en.wikipedia.org/wiki/Transovarial%20transmission | Transovarial or transovarian transmission (transmission from parent to offspring via the ovaries) occurs in certain arthropod vectors as they transmit pathogens from parent to offspring. This process, used by a wide variety of parasites, is also known as vertical transmission. For example, Rickettsia rickettsii, carried within ticks, is passed on from parent to offspring tick by transovarial transmission. This is in contrast to parasites such as Rickettsia prowazekii, which are not passed on by transovarian transmission due to killing the vector that carries it (in this case, the human louse). Other examples of parasites that use this mechanism of transmission include the aedes mosquito vector of the yellow fever virus and in phlebotomine sandflies that transmit pappataci fever.
Richard Dawkins in The Extended Phenotype notes that "bacterial endosymbionts of insects which are transmitted transovarially" share an interest in the "success of their host's gametes ... as well as the survival of their host's body." In this case, "the interest of the host genes and parasite genes might not be quite identical, but they would..... be very much closer than the case of fluke and snail." where host and parasite have different means of propagation into the next generation, and therefore more divergent interests.
See also
Transstadial transmission
References
Murray, Patrick R.; Rosenthal, Ken S.; Pfaller, Michael A. Medical Microbiology, Fifth Edition. United States: Elsevier Mosby, 2005
Parasitology
Epidemiology | Transovarial transmission | Environmental_science | 342 |
5,542,455 | https://en.wikipedia.org/wiki/Outrageous%20Betrayal | Outrageous Betrayal: The Dark Journey of Werner Erhard from est to Exile is a non-fiction book written by freelance journalist Steven Pressman and first published in 1993 by St. Martin's Press. The book gives an account of Werner Erhard's early life as Jack Rosenberg, his exploration of various forms of self-help techniques, and his foundation of Erhard Seminars Training "est" and later of Werner Erhard and Associates and of the est successor course, "The Forum". Pressman details the rapid financial success Erhard had with these companies, as well as controversies relating to litigation involving former participants in his courses. The work concludes by going over the impact of a March 3, 1991 60 Minutes broadcast on CBS where members of Erhard's family made allegations against him, and Erhard's decision to leave the United States.
Representatives of Werner Erhard and of Landmark Worldwide, the successor company to The Forum, regarded the book as being "defamatory".
Author
Pressman worked as a journalist after graduating from college in 1977. He worked as a journalist for Orange City News, the Los Angeles Daily Journal, California Lawyer magazine, and Congressional Quarterly's Weekly Report. During his time performing research for and writing Outrageous Betrayal, Pressman published articles for the Legal Times newspaper and wrote articles and served as a senior editor for California Republic. In 1993, Pressman worked as a San Francisco-based legal journalist for California Lawyer.
Research
In the "Acknowledgments" section of Outrageous Betrayal, Pressman wrote that he relied upon both named and unnamed sources for information in the book, in addition to "previously published accounts, court transcripts, depositions, and other documents in which various individuals have recounted earlier conversations". In an article on fair use for Columbia Journalism Review, Pressman noted that he "gathered reams of written materials -- some of it private and confidential -- that were helpful in drawing a comprehensive portrait of my subject". In the Daily Journal, Pressman wrote that legal counsel for the book's publisher insisted on numerous changes to the book "in order to reduce, if not eliminate, the possibility of a successful suit for copyright infringement".
By 1993, Pressman and St. Martin's Press had received approximately two dozen letters from Erhard's attorney Walter Maksym, though Erhard's representatives had yet to see the book itself. Maksym told the San Francisco Daily Journal in March 1993 that he wanted to "fact check the book", because he believed that "this is a first-time unknown author who apparently has interviewed only people who have negative things to say", and stated "We have cautioned the publisher that they are responsible for the accuracy of the book." Charlie Spicer, a senior editor at St. Martin's Press, described the actions of Erhard's representatives with regard to the book as "a desperate campaign by someone with something to hide". The author himself made specific reference to his legal support, mentioning "the potential legal rapids that confront authors writing these days about controversial subjects".
Contents
In Outrageous Betrayal, Steven Pressman gives a chronological account of Erhard's life and businesses, from high-school years through his formation of companies that delivered awareness training and the later controversies surrounding his business and family life. The book goes into detail regarding his early life as Jack Rosenberg and his name-change to Werner Erhard, his move to California, and the initial inspirations behind the training that would become "est". Pressman writes that Erhard took inspiration from the self-help course Mind Dynamics, cybernetics, from the books Think and Grow Rich by Napoleon Hill, and Psycho-Cybernetics by Maxwell Maltz, and from Scientology and the writings of L. Ron Hubbard. He also notes how an attorney skilled in tax law helped Erhard in forming his first awareness-training company, Erhard Seminars Training.
Pressman notes how Erhard and his businesses became successful within two years of foundation, and writes that his awareness-training programs trained over half a million people in his courses and brought in tens of millions of dollars in revenue. The book then describes controversies relating to both Erhard's businesses and his reported treatment of his family. Pressman also describes the successor company to Est, Werner Erhard and Associates, and Erhard's decision to sell the "technology" of his course The Forum to his employees and to leave the United States. The book's epilogue includes a firsthand account of a Landmark Forum seminar led by the former Est-trainer Laurel Scheaf in 1992.
Reception
St. Martin's Press first published Outrageous Betrayal in 1993, and Random House published a second edition of the text in 1995.
An analysis in Kirkus Reviews, noting the choice of title by the author, asserted that Pressman: "makes no pretense to objectivity here." Kirkus Reviews criticized the book, saying "What the author dramatically fails to provide by bearing down on the negative (to the extent that nearly all his informants denounce est and its founder) is any real understanding of est's teachings--and of why they appealed so deeply to so many." Paul S. Boyer, professor of history at the University of Wisconsin–Madison, reviewed the book in The Washington Post. Boyer wrote that the book "nicely recounts the bizarre tale" of Werner Erhard, saying "Pressman tells his fascinating story well." However he also commented that the book gives "only the sketchiest historical context" of est and its roots in societal experiences.
A review by Mary Carroll published in the American Library Association's Booklist noted that the controversy surrounding Erhard was not new, but she wrote that "Pressman pulls the details together effectively." Carroll went on to comment: "Outrageous Betrayal is a disturbing but fascinating object lesson in the power of charisma divorced from conscience." Frances Halpern of the Los Angeles Times called the book a "damning biography".
In 1995, Outrageous Betrayal was cited in a report on the United States Department of Transportation by the United States House of Representatives Committee on Appropriations in a case unrelated to Erhard or Est. This was in reference to a Congressional investigation of Gregory May and controversial trainings given by his company Gregory May Associates (GMA) to the Federal Aviation Administration. The testimony given stated that, according to Outrageous Betrayal, a member of GMA's board had been influenced by Erhard Seminars Training and the Church of Scientology.
See also
Human Potential Movement
Journalism sourcing
Large Group Awareness Training
Notes
References
1993 non-fiction books
Human Potential Movement
Personal development
Werner Erhard | Outrageous Betrayal | Biology | 1,353 |
48,981,762 | https://en.wikipedia.org/wiki/Attainable%20region%20theory | Attainable region (AR) theory is a branch of chemical engineering, specifically chemical reaction engineering, that uses geometric and mathematical optimization concepts to assist in the design of networks of chemical reactors. AR theory is a method to help define the best reactor flowsheet using graphical techniques for a desired duty or objective function.
Origin of AR theory
The initial concept of an attainable region for chemical processes was proposed by Fritz Horn in 1964, where he believed in geometric methods to improve process design. These ideas were later refined and made specific to chemical reactors by co-developers David Glasser, Diane Hildebrandt, and Martin Feinberg.
Overview
The AR is defined as the collection all possible outcomes for all conceivable reactor combinations. Geometrically, the AR may (for instance) be represented as a convex region in state space representing all possible outlet compositions for all reactor combinations. A combination of reactors is often termed a reactor structure. An example of the reactors that are considered for this theory are Continuous flow stirred-tank reactor (CSTR) and a Plug flow reactor model (PFR).
Knowledge of the AR helps to address two areas in chemical reactor design:
The reactor network synthesis problem: Given a system of reactions and feed point, construction of the AR assists with determining an optimal reactor structure that achieves a desired duty or objective function. That is, AR theory assists with understanding specifically what type and combination of the chemical reactors are best suited for a particular system and duty.
Performance targeting: Given an existing reactor design, knowledge of the AR assists with understanding if there are other reactor structures that could achieve superior performance, by comparison to its location in the AR. Seeing as the AR represents all reactor designs by definition, different proposed reactor designs must lie as a point in or on the AR in state space. The effectiveness of each design may then all be assessed by comparison the AR and their relation to objective functions if any.
Applications of theory
Examples of where AR theory can be applied, include:
The design of batch reactor networks; and
Comminution (Milling).
See also
Chemical reactors
Chemical reaction engineering
References
External links
Official web site
Other official web site
Chemical engineering
Chemical reactors
Chemical reaction engineering | Attainable region theory | Chemistry,Engineering | 440 |
1,160,209 | https://en.wikipedia.org/wiki/Poor%20man%27s%20copyright | Poor man's copyright is a method of using registered dating by the postal service, a notary public or other highly trusted source to date intellectual property, thereby helping to establish that the material has been in one's possession since a particular time. The concept is based on the notion that, in the event that such intellectual property were to be misused by a third party, the poor-man's copyright would at least establish a legally recognized date of possession before any proof which a third party may possess.
In countries with no central copyright registration authority, it can be difficult for an author to prove when their work was created. The United Kingdom Patent Office says this:
... a copy could be deposited with a bank or solicitor. Alternatively, a creator could send himself or herself a copy by special delivery post (which gives a clear date stamp on the envelope), leaving the envelope unopened on its return. A number of private companies operate unofficial registers, but it would be sensible to check carefully what you will be paying for before choosing this route.
This does not prove that a work is original or created by you...
There is no provision in United States copyright law regarding any such type of protection. A work of original authorship is protected by United States copyright law once it is fixed in a tangible medium of expression. According to section 412 of the U.S. Copyright Act of 1976 (17 U.S.C. 408), registration of a work with the Copyright Office is a prerequisite for copyright protection. Poor man's copyright is therefore not a substitute for registration. Eric Goldman has noted that there is an absence of cases that give any value to the poor man's copyright. He also states, "To establish copyright infringement, the author must show copying-in-fact and wrongful copying. The postmark has no relevance to the wrongful copying question." However, according to the Copyright Alliance, the postmark could provide some value in an infringement action if it is used as evidence that the work existed on a particular date, or before the date of creation of another work.
See also
Copyright registration
Soleau envelope
References
Authentication methods
Copyright law
Postal systems | Poor man's copyright | Technology | 446 |
38,289,515 | https://en.wikipedia.org/wiki/Extracellular%20RNA | Extracellular RNA (exRNA) describes RNA species present outside of the cells in which they were transcribed. Carried within extracellular vesicles, lipoproteins, and protein complexes, exRNAs are protected from ubiquitous RNA-degrading enzymes. exRNAs may be found in the environment or, in multicellular organisms, within the tissues or biological fluids such as venous blood, saliva, breast milk, urine, semen, menstrual blood, and vaginal fluid. Although their biological function is not fully understood, exRNAs have been proposed to play a role in a variety of biological processes including syntrophy, intercellular communication, and cell regulation. The United States National Institutes of Health (NIH) published in 2012 a set of Requests for Applications (RFAs) for investigating extracellular RNA biology. Funded by the NIH Common Fund, the resulting program was collectively known as the Extracellular RNA Communication Consortium (ERCC). The ERCC was renewed for a second phase in 2019.
Background
Both prokaryotic and eukaryotic cells are known to release RNA, and this release can be passive or active. The Endosomal Sorting Complex Required for Transport (ESCRT) machinery was previously considered as a possible mechanism for RNA secretion from the cell, but more recently research studying microRNA secretion in human embryonic kidney cells and Cercopithecus aethiops kidney cells identified neutral sphingomyelinase 2 (nSMase2), an enzyme involved in ceramide biosynthesis, as a regulator of microRNA secretion levels. ExRNAs are often found packaged within vesicles such as exosomes, ectosomes, prostasomes, microvesicles, and apoptotic bodies. Although RNAs can be excreted from the cell without an enveloping container, ribonucleases present in extracellular environments would eventually degrade the molecule.
Types
Extracellular RNA should not be viewed as a category describing a set of RNAs with a specific biological function or belonging to a particular RNA family. Similar to the term "non-coding RNA", "extracellular RNA" defines a group of several types of RNAs whose functions are diverse, yet they share a common attribute which, in the case of exRNAs, is existence in an extracellular environment. The following types of RNA have been found outside the cell:
Messenger RNA (mRNA)
Transfer RNA (tRNA)
MicroRNA (miRNA)
Small interfering RNA (siRNA)
Long non-coding RNA (lncRNA)
Though prevalent inside of the cell, ribosomal RNA (rRNA) does not seem to be a common exRNA. Efforts by Valadi et al. to characterize exosomal RNA using the Agilent Bioanalyzer technology showed little to no trace of 18S and 28S rRNA in exosomes secreted by MC/9 murine mast cells, and similar conclusions were made by Skog et al. for rRNA in gliobastoma microvesicles.
Function
To function or even survive as full-length RNA in extracellular environments, exRNA must be protected from digestion by RNases. This requirement does not apply to prokaryotic syntrophy, where digested nucleotides are recycled. exRNA can be shielded from RNases by RNA binding proteins (RBPs), on their own or within/associated with lipoprotein particles and extracellular vesicles. Extracellular vesicles in particular are thought to be a way to transport RNA between cells, in a process that may be general or highly specific, for example, due to incorporation of markers of the parent cell that may be recognized by receptors on the recipient cell. Biochemical evidence supports the idea that exRNA uptake is a common process, suggesting new pathways for intercellular communication. As a result, the presence, absence, and relative abundance of certain exRNAs can be correlated with changes in cellular signaling and may indicate specific disease states.
Despite a limited understanding of exRNA biology, current research has shown the role of exRNAs to be multi-faceted. Extracellular miRNAs are capable of targeting mRNAs in the recipient cell through RNA interference pathways. In vitro experiments have shown the transfer of specific exRNAs into recipient cells inhibiting protein expression and preventing cancer cell growth. In addition to mRNAs being regulated by exRNAs, mRNAs can act as exRNAs to carry genetic information between cells. Messenger RNA contained in microvesicles secreted from glioblastomal cells were shown to generate a functional protein in recipient (human brain microvascular endothelial) cells in vitro. In another study of extracellular mRNAs, mRNAs transported by microvesicles from endothelial progenitor cells (EPCs) to human microvascular and macrovascular endothelial cells triggered angiogenesis in both the in vitro and in vivo setting. Work by Hunter et al. used Ingenuity Pathway Analysis (IPA) software that associated exRNAs found in human blood microvesicles with pathways involved in blood cell differentiation, metabolism, and immune function. These experimental and bioinformatics analyses favor the hypothesis that exRNAs play a role in numerous biological processes.
Detection
Several methods have been developed or adapted to detect, characterize, and quantify exRNA from biological samples. RT-PCR, cDNA microarrays, and RNA sequencing are common techniques for RNA analysis. Applying these methods to study exRNAs mainly differs from cellular RNA experiments in the RNA isolation and/or extraction steps.
RT-PCR
For known exRNA nucleotide sequences, RT-PCR can be applied to detect their presence within a sample as well as quantify their abundance. This is done through first reverse transcribing the RNA sequence into cDNA. The cDNA then serves as a template for PCR amplification. The major benefits of using RT-PCR are its quantitative accuracy in a dynamic range and increased sensitivity compared to methods such as RNase protection assays and dot blot hybridization. The disadvantage to RT-PCR is the requirement of costly supplies, and the necessity of sound experimental design and an in-depth understanding of normalization techniques in order to obtain accurate results and conclusions.
Microfluidics
Microfluidic platforms such as the Agilent Bioanalyzer are useful in assessing the quality of exRNA samples. With the Agilent Bioanalyzer, a lab-on-chip technology that uses a sample of isolated RNA measures the length and quantity of RNA in the sample, and the results of the experiment can be represented as a digital electrophoresis gel image or an electropherogram. Because a diverse range of RNAs can be detected by this technology, it is an effective method for more generally determining what types of RNAs are present in exRNAs samples through using size characterization.
cDNA microarrays
Microarrays allow for larger-scale exRNA characterization and quantification. Microarrays used for RNA studies first generate different cDNA oligonucleotides (probes) that are attached to the microarray chip. An RNA sample can then be added to the chip, and RNAs with sequence complementarity to the cDNA probe will bind and generate a fluorescent signal that can be quantified. Micro RNA arrays have been used in exRNA studies to generate miRNA profiles of bodily fluids.
RNA sequencing
The advent of massively parallel sequencing (next-generation sequencing) lead to variations in DNA sequencing that allowed for high-throughput analyses of many genomic properties. Among these DNA sequencing-derived methods is RNA sequencing. The main advantage of RNA sequencing over other methods for exRNA detection and quantification is its high-throughput capabilities. Unlike microarrays, RNA sequencing is not constrained by factors such as oligonucleotide generation, and the number of probes that can be added to a chip. Indirect RNA sequencing of exRNA samples involves generating a cDNA library from the exRNAs followed by PCR amplification and sequencing. In 2009, Helicos Biosciences published a method for directly sequencing RNA molecules called Direct RNA sequencing (DRS™). Regardless of the RNA sequencing platform, inherent biases exist at various steps in the experiment, but methods have been proposed to correct for these biases with promising results.
Clinical significance
As growing evidence supports the function of exRNAs as intercellular communicators, research efforts are investigating the possibility of utilizing exRNAs in disease diagnosis, prognosis, and therapeutics.
Biomarkers
The potential of extracellular RNAs to serve as biomarkers is significant not only because of their role in intercellular signaling but also due to developments in next generation sequencing that enable high throughput profiling. The simplest form of an exRNA biomarker is the presence (or absence) of a specific extracellular RNA. These biological signatures have been discovered in exRNA studies of cancer, diabetes, arthritis, and prion-related diseases. Recently, a bioinformatics analysis of extracellular vesicles extracted from Trypanosoma cruzi, in which SNPs were mined from transcriptomic data, suggested that exRNAs could be biomarkers of neglected diseases such as Chagas disease.
Cancer
A major research area of interest for exRNA has been its role in cancer. The table below (adapted from Kosaka et al.) lists several types of cancer in which exRNAs have been shown to be associated:
See also
Environmental DNA
non-coding RNA
International Society for Extracellular Vesicles
Journal of Extracellular Vesicles
References
External links
NIH request for applications for 'Reference Profiles of Human Extracellular RNA'
International Society for Extracellular Vesicles
miRandola: Extracellular Circulating microRNAs Database
RNA
Molecular genetics
Non-coding RNA | Extracellular RNA | Chemistry,Biology | 2,038 |
15,132,605 | https://en.wikipedia.org/wiki/DeathSpank | DeathSpank, also known as DeathSpank: Orphans of Justice, is an action role-playing video game developed by Hothead Games and published by Electronic Arts. It was created by game designers Ron Gilbert and Clayton Kauzlaric. The game was released on July 13, 2010 on the PlayStation 3 via the PlayStation Network and on July 14, 2010 on the Xbox 360 via Xbox Live Arcade. The Microsoft Windows and Mac OS X versions were released October 26, 2010 and December 14, 2010 respectively, via Steam.
DeathSpank follows the titular character DeathSpank in his quest to find an item known as The Artifact. The game was originally supposed to be the first of a two-part series. The second half of the series, entitled DeathSpank: Thongs of Virtue was first released on September 20, 2010. Gilbert described DeathSpank as being "Act I" in the story, and Thongs of Virtue as being "Acts II and III". However, it was later announced that Deathspank was returning for a third game entitled, The Baconing, abandoning the protagonist's name in its title. The third game was released on August 30, 2011.
DeathSpank has received generally positive reviews from critics, who cited influences from both the Monkey Island and Diablo games.
Gameplay
DeathSpank is an action role-playing game which also features elements from graphic adventure games. Combat gameplay is similar to Diablo. Players can acquire several pieces of armor and weaponry, each with different abilities and attributes. During combat players can chain attacks in combos, which in turn deal more damage with each hit. As more hits are gained on enemies, DeathSpank's Justice Meter will fill. Once full, the player can unleash more powerful attacks for a limited time.
In-game conversations with non-player characters are also a large part of the game. DeathSpank features advanced dialog options, similar to LucasArts' Monkey Island series which play a large part in unfolding the game's story. These conversations may lead to quests for DeathSpank. In all, the game features 79 side quests in addition to the 33 quests required to advance the main plot. Once the game is completed the player can return and complete any unfinished side quests.
DeathSpank is designed to be playable in short segments, and has three difficulty levels. It contains about 8 to 12 hours of gameplay depending on choices made by the player during the game. The world of DeathSpank is presented as a rotating cylinder, with the display having a rounded element, similar to Animal Crossing: Wild World. The world is a mixture of 2D and 3D props on 3D terrain, and is rendered without load screens as the player moves between areas. The game also features a local cooperative mode, in which the second player takes the role of Sparkles the Wizard. Sparkles is equipped with multiple spells which provide support to DeathSpank, including a healing spell.
Synopsis
DeathSpank is set in a fantasy medieval world. It revolves around a character named DeathSpank, who has searched his entire life for an item known as The Artifact, a mysterious object whose purpose is equally mysterious. He travels with a wizard known as Sparkles, and the duo seek to claim The Artifact and rid the land of evil. The story begins with The Artifact just out of DeathSpank's reach. Unable to claim it, he meets with a local witch, who promises to help him in exchange for his services. He provides her with her requested items, and eventually obtains The Artifact.
The victory is short lived, however, as a group of henchmen who serve the evil Lord Von Prong steal The Artifact and all of DeathSpank's equipment. Traveling to a nearby town, he earns new weaponry from the townsfolk in exchange for doing good deeds. Re-equipped, he sets his sights back on The Artifact and Lord Von Prong. After a lengthy journey with several side quests throughout various locations, DeathSpank faces off against Lord Von Prong. He defeats Von Prong, and DeathSpank ends with a prelude to the game's sequel.
Development and marketing
DeathSpank was first confirmed on January 9, 2008 via a press release. The release stated that game designer Ron Gilbert would be joining forces to develop the game. Gilbert described it as "Monkey Island meets Diablo." Three cinematic teaser trailers for DeathSpank were shown at Penny Arcade Expo 2008. During the 2009 Penny Arcade Expo DeathSpank was showcased at the Hothead Games booth, with live gameplay being demonstrated by staff, along with examples of story elements, and dialogue trees. It was announced on March 4, 2010 that Electronic Arts would publish the game.
The game was released on July 13, 2010, on the PlayStation Network and July 14, 2010, on Xbox Live Arcade. It was later released for Microsoft Windows on October 26, 2010, and on Mac OS X December 14, 2010. The PC and Mac OS X versions support a wide range of resolutions, the ability to run the game windowed, input by keyboard and mouse as well as gamepad, alternate control schemes, and a key mapping ability. Gameplay enhancements based on feedback from the console versions include an equipment comparison function, a treasure chest feature in each town and major area, a new streamlined user interface and more. These versions also make use of Steam's cloud saving and achievement functionalities and leaderboards.
In an interview with Gamasutra in June 2008, Gilbert stated that DeathSpank would be an episodic series of games. On March 30, 2009, Ron Gilbert confirmed on his blog that the game would no longer be episodic. Gilbert later revealed that the game had once again become episodic due to the game's size. "Towards the end of production it was determined what we had built was too big for a downloadable game, so the decision was made to split the game in half and the climactic battle with Lord Von Prong was the perfect place. That battle is in essence the end of Act I and it had a nice WTF moment that provided a nice cliff hanger" he stated. Gilbert has described DeathSpank as being "Act I" in his story, and Thongs of Virtue as being "Acts II and III".
The title character originated in Ron Gilbert's Grumpy Gamer comics, created by Gilbert and Clayton Kauzlaric, who they later developed further. The character DeathSpank is voiced by Michael Dobson. Gilbert and Kauzlaric created a rough design for the game and pitched it to publishers for over four years without success. Previously, Gilbert had consulted for Penny Arcade Adventures: On the Rain-Slick Precipice of Darkness at Hothead Games; he contacted them and a deal was struck for the company to develop the game. A more in-depth design for DeathSpank was then produced. Kauzlaric remained involved with the project, consulting on design, story and concept art. Gilbert departed Hothead Games upon completion of the game.
Reception
DeathSpank has received generally positive reviews from critics. At aggregate website GameRankings it holds scores of 79-80% for the platforms it was released on. Fellow aggregate website Metacritic reports similar scores, with both the PlayStation 3 and Xbox 360 versions averaging 79/100 and the PC version holding a score of 78/100. The game has sold over 91,000 units as of October 2010 with a total of over 97,000 units as of year-end 2010. Year-end 2011 analyses showed a movement of over 122,000 units. The PlayStation 3 version sold similarly, with nearly 107,000 units sold at the end of 2010. Some critics cited elements The Secret of Monkey Island and Diablo in the game.
The game's humor was lauded among most critics. Thierry Nguyen of 1UP.com enjoyed the character's interactions, and noted, "a sort of deadpan absurdity where pretty much anything [...] gets said as naturally as we would discuss the time of day." Game Revolution's Duke Ferris agreed, and stated the game was "genuinely funny." He then pointed out several instances of humorous quests, conversations, and actions. XPlay's Rob Manuel stated that "most of the thanks here should go to Ron Gilbert." He then referenced two of Gilbert's previous games, The Secret of Monkey Island and Maniac Mansion. Manuel went on to add, "his sharp and often dark sense of humor permeates everything from quests to settings." Eurogamer's Dan Pearson felt the humor was borderline irreverent and said, "I can't help feel I'm not really part of DeathSpanks target audience."
Critics universally applauded the unique art style of DeathSpank. GameSpot's Tom Mc Shea called the visuals "imaginative", and added, "the colorful visuals are reason enough to check out every corner." The reviewers from Australia's Good Game said they "liked [DeathSpanks] rolling countryside effect, so you feel like you're walking around a small planetoid filled with pop-up 2D sprites." Joystiq's Randy Nelson lauded the visual and audio design of the game, and stated, "[it] resonates with charm created by artists, animators and Gilbert's own writing." GamePros Will Herring added that the game had a "charming visual design."
The gameplay was also point of high praise among most reviewers, however elements of it were criticized. Martin Gaston of VideoGamer.com stated, "the game goes out of its way to ensure you're always taking on new and different enemies." Randy Nelson of Joystiq noted that the game was diverse in its puzzles, adding that the developers strayed from stereotypical quotas such as killing a certain number of enemies. IGN's Kristine Steimer disagreed, and noted that due to experiences in past Gilbert-designed games, she expected more quests which included puzzles. She stated, "I was expecting a bit more given the developer's background." Martin Gaston of VideoGamer.com later stated that DeathSpank "all feels a bit diluted, as if a single drop of Diablo and Monkey Island has been added to an entire gallon of water." Destructoid's Nick Chester praised the combat system and role-playing elements. "Chaining attacks is exceedingly satisfying, experimenting with various weapon combinations nearly as addictive as finding them in the first place" stated Chester Some reviewers noted that the addition of cooperative gameplay, while welcome, was unbalanced and underdeveloped. GamePros Will Herring disagreed and stated that the second player's character "won't steal the screen from the titular lead, but the option to team up and complete the game with a friend is a fun and worthwhile distraction."
The PC version of the game received praise for its faithful reproduction of gameplay from the console versions. The addition of keyboard and mouse gameplay received mixed views from critics. Game Revolution's Josh Laddin felt that the keyboard controls were frustrating and said, "the keyboard controls aren't as intuitive as a gamepad." However Marko Djordjevic of GameFocus disagreed and stated, "once you get the hang of it [...] it feels exactly as you’d expect." Djordjevic further appreciated that the cooperative gameplay was ported over from the console versions.
Sequels
DeathSpank: Thongs of Virtue, the second title in the series, was announced August 23, 2010 and first released September 20, 2010. It continues where DeathSpank ends, and features the use of ranged weapons such as machine guns and rocket launchers. It was first released on the PlayStation 3 on September 21, 2010. The Xbox 360 version was released September 22, 2010 and the PC version November 30, 2010. The Mac OS X version was December 14, 2010.
A third game, The Baconing, was released in August 2011. The plot follows DeathSpank after he decides to try on all of the Thongs of Virtue at once. This spawns an evil incarnation of himself, the Anti-Spank. DeathSpank must travel to the Fires of Bacon to destroy the thongs and the Anti-Spank. It will be the first DeathSpank title not to feature the titular character in its name; it has been reported that this has nothing to do with the departure of Ron Gilbert from Hothead Games.
References
External links
Role-playing video games
Action-adventure games
Action role-playing video games
Cooperative video games
Electronic Arts franchises
Electronic Arts games
Fantasy video games
MacOS games
PlayStation Network games
Video games developed in Canada
Video games scored by Jeff Tymoschuk
Xbox 360 Live Arcade games
Xbox 360 games
PlayStation 3 games
Windows games
Multiplayer and single-player video games
2010 video games
Asymmetrical multiplayer video games
Hothead Games games | DeathSpank | Physics | 2,650 |
41,969,260 | https://en.wikipedia.org/wiki/National%20Supercomputer%20Centre%20in%20Sweden | The National Supercomputer Centre in Sweden (NSC) is located in Linköping and operates the Triolith supercomputer which achieved 407.2 Teraflops on the LINPACK benchmark which rendered it place 79 on the November 2013 issue of the Top500 list of the fastest supercomputers in the world.
Notes
External links
National Supercomputer Centre in Sweden (NSC)
Supercomputer sites | National Supercomputer Centre in Sweden | Technology | 91 |
43,211,917 | https://en.wikipedia.org/wiki/Aphanopleura%20zangelanica | Aphanopleura zangelanica, the Zangelanian aphanopleura, is a species in the family Apiaceae that is endemic to the Zəngilan district of Azerbaijan. It is only known from its type specimen collected in 1971.
References
Apioideae
Endemic flora of Azerbaijan
Plants described in 1975
Species known from a single specimen | Aphanopleura zangelanica | Biology | 74 |
6,606,771 | https://en.wikipedia.org/wiki/Bis%28trimethylsilyl%29amine | Bis(trimethylsilyl)amine (also known as hexamethyldisilazane and HMDS) is an organosilicon compound with the molecular formula [(CH3)3Si]2NH. The molecule is a derivative of ammonia with trimethylsilyl groups in place of two hydrogen atoms. An electron diffraction study shows that silicon-nitrogen bond length (173.5 pm) and Si-N-Si bond angle (125.5°) to be similar to disilazane (in which methyl groups are replaced by hydrogen atoms) suggesting that steric factors are not a factor in regulating angles in this case. This colorless liquid is a reagent and a precursor to bases that are popular in organic synthesis and organometallic chemistry. Additionally, HMDS is also increasingly used as molecular precursor in chemical vapor deposition techniques to deposit silicon carbonitride thin films or coatings.
Synthesis and derivatives
Bis(trimethylsilyl)amine is synthesized by treatment of trimethylsilyl chloride with ammonia:
2 (CH3)3SiCl + 3 NH3 → [(CH3)3Si]2NH + 2 NH4Cl
Ammonium nitrate together with triethylamine can be used instead. This method is also useful for 15N isotopic enrichment of HMDS.
Alkali metal bis(trimethylsilyl)amides result from the deprotonation of bis(trimethylsilyl)amine. For example, lithium bis(trimethylsilyl)amide (LiHMDS) is prepared using n-butyllithium:
[(CH3)3Si]2NH + BuLi → [(CH3)3Si]2NLi + BuH
LiHMDS and other similar derivatives: sodium bis(trimethylsilyl)amide (NaHMDS) and potassium bis(trimethylsilyl)amide (KHMDS) are used as a non-nucleophilic bases in synthetic organic chemistry.
Use as reagent
Hexamethyldisilazane is employed as a reagent in many organic reactions:
1) HMDS is used as a reagent in condensation reactions of heterocyclic compounds such as in the microwave synthesis of a derivative of xanthine:
2) The HMDS mediated trimethylsilylation of alcohols, thiols, amines and amino acids as protective groups or for intermediary organosilicon compounds is found to be very efficient and replaced TMSCl reagent.
Silylation of glutamic acid with excess hexamethyldisilazane and catalytic TMSCl in either refluxing xylene or acetonitrile followed by dilution with alcohol (methanol or ethanol) yields the derived lactam pyroglutamic acid in good yield.
HMDS in the presence of catalytic iodine facilitates the silylation of alcohols in excellent yields.
3) HMDS can be used to silylate laboratory glassware and make it hydrophobic, or automobile glass, just as Rain-X does.
4) In gas chromatography, HMDS can be used to silylate OH groups of organic compounds to increase volatility, this way enabling GC-analysis of chemicals that are otherwise non-volatile.
Other uses
In photolithography, HMDS is often used as an adhesion promoter for photoresists. Best results are obtained by applying HMDS from the gas phase on heated substrates.
In electron microscopy, HMDS can be used as an alternative to critical point drying during sample preparation.
In pyrolysis-gas chromatography-mass spectrometry, HMDS is added to the analyte to create silylated diagnostic products during pyrolysis, in order to enhance detectability of compounds with polar functional groups.
In plasma-enhanced chemical vapor deposition (PECVD), HMDS is used as a molecular precursor as a replacement to highly flammable and corrosive gasses like SiH4, CH4, NH3 as it can be easily handled. HMDS is used in conjunction with a plasma of various gases such as argon, helium and nitrogen to deposit SiCN thin films/coatings with excellent mechanical, optical and electronic properties.
See also
Hexamethyldisiloxane
Metal bis(trimethylsilyl)amides
References
Amines
Trimethylsilyl compounds
Reagents for organic chemistry | Bis(trimethylsilyl)amine | Chemistry | 942 |
69,299,015 | https://en.wikipedia.org/wiki/Robert%20Glaeser | Robert Martin Glaeser (born July 20, 1937) is an American biochemist. He is a professor emeritus of Biochemistry, Biophysics and Structural Biology at the University of California, Berkeley and a faculty scientist at Lawrence Berkeley National Laboratory, in Berkeley, California, US. His main research area is electron diffraction and membrane models.
Glaeser is known for his pioneering work in cryogenic electron microscopy (cryo-EM), where he established how radiation damage was a limiting factor for imaging resolution and how freezing hydrated specimens allowed for more tolerance to radiation damage. He also pushed electron imaging microscopy resolution and contrast by studying the effect of beam-induced movement on the resolution and developed methods for weak-phase imaging.
Glaeser studied at the University of Wisconsin – Madison (B.A. 1959) and the University of California, Berkeley (Ph.D. 1964). He was then a postdoc at the University of Oxford (1963/64) and University of Chicago (1964/65). In 1988/89 he was a visiting scientist at the Max Planck Institute for Biochemistry (MPIB) in Martinsried near Munich, and later a professor at the University of California, Berkeley.
Awards
2021: Lawrence Berkeley National Laboratory Lifetime Achievement award
2018: Glenn T. Seaborg Medal
2016: member of the American Academy of Arts and Sciences and the National Academy of Sciences
1983: Guggenheim Fellowship of the John Simon Guggenheim Memorial Foundation.
References
1937 births
Living people
Structural biologists | Robert Glaeser | Chemistry | 304 |
77,670,151 | https://en.wikipedia.org/wiki/Absconditabacterales%20genetic%20code | The Absconditabacterales genetic code (tentative code number 37) translates UGA to glycine, and CGG and GCA to tryptophan, as determined by the codon assignment software Codetta; it was further shown that these recodings are associated with three special tRNAs with appropriate anticodons and tRNA identity elements. Codetta called the Absconditibacterales code (sometimes leaving the rare CGA codon uncalled) for the following genome assemblies: GCA_002792495.1, GCA_001007975.1, GCA_003488625.1, GCA_003260355.1, GCA_003242865.1, GCA_000350285.1, GCA_002746475.1, GCA_007116275.1, GCA_007115995.1, GCA_002361595.1, GCA_000503875.1, GCA_003543185.1, GCA_002441085.1, and GCA_002791215.1. Review of the GTDB taxonomy system (release 220) for the order Absconditabacterales (phylum Patescibacteria) left two questionable genome assemblies (GCA_002414185.1, for which Codetta had called the CGA codon Arg, and GCA_937862565.1, the only known genome from the CALMFT01 family and untested by Codetta); spot-checking these two genomes shows that they both have all three special tRNAs, suggesting that the code is universal across the order.
See also
Genetic codes: list of alternative codons
List of genetic codes
References
Genetics | Absconditabacterales genetic code | Biology | 401 |
54,275,492 | https://en.wikipedia.org/wiki/Carpenter%20v.%20United%20States | Carpenter v. United States, , is a landmark United States Supreme Court case concerning the privacy of historical cell site location information (CSLI). The Court held that government entities violate the Fourth Amendment to the United States Constitution when accessing historical CSLI records containing the physical locations of cellphones without a search warrant.
Prior to Carpenter, government entities could obtain cellphone location records from service providers by claiming the information was required as part of an investigation, without a warrant, but the ruling changed this procedure. Recognizing the influence of new consumer communications devices in the 2010s, the Court expanded its conceptions of constitutional rights toward the privacy of this type of data. However, the Court emphasized that the Carpenter ruling was narrowly restricted to the precise types of information and search procedures that were relevant to this case.
Background
Cell site location information (CSLI)
Cellular telephone service providers are able to find the location of cell phones through either global positioning system (GPS) data or cell site location information (CSLI), in the process of connecting calls and data transmissions. CSLI is captured by nearby cell towers, and this information is used to triangulate the location of phones. Service providers capture and store this data for business purposes, such as troubleshooting, maximizing network efficiencies, and determining whether to charge customers roaming fees for particular calls.
The data can also illustrate the historical movements of a cellphone. Thus, anyone with access to this data has the ability to know where the phone has been and what other cell phones were in the same area at a given time. When users travel with their cellphones, this data can theoretically illustrate every place a person has traveled, and possibly the locations of other people encountered via their corresponding data.
Third-party doctrine
Prior to Carpenter, the Supreme Court consistently held that a person had no reasonable expectation of privacy in regard to information voluntarily turned over to third-parties such as telephone companies, and therefore a search warrant is not required when government officials seek this information. This legal theory is known as the third-party doctrine, established by the Supreme Court in Smith v. Maryland (1979), in which the Court determined that government can obtain a list of phone numbers dialed from a suspect's phone.
By the 2010s, cellphones and particularly smartphones had become important tools for nearly every person in the United States. Many applications, such as GPS navigation and location tools, require a phone to send and receive information constantly, including the exact location of the phone, often without an affirmative action on the part of its owner. As technology advanced in the 2010s, the Supreme Court began to modify its precedents on government searches of personal communications devices, given new consumer behaviors that may transcend the third-party doctrine.
Background
Between December 2010 and March 2011, several individuals in the Detroit, Michigan area conspired and participated in armed robberies at RadioShack and T-Mobile stores across the region. In April 2011, four of the robbers were captured and arrested. The petitioner, Timothy Carpenter, was not among the initial group of arrestees. One of those arrested confessed and turned over his phone so that FBI agents could review the calls made from his phone around the time of the robberies. The agents obtained a search warrant to inspect the information in that arrestee's phone, in order to find additional contacts of the arrestee and compile more evidence about the crime ring.
From the historical cell site records on the arrestee's phone, the agents confirmed that Timothy Carpenter was also part of the crime ring, and proceeded to compile information about the location of his phone over 127 days. In turn, this information revealed that Carpenter had been within a two-mile radius of four robberies at the times they were perpetrated. This evidence was used to support Carpenter's arrest. At criminal court, Carpenter was found guilty of several counts of aiding and abetting robberies that affected interstate commerce, and another count of using a firearm during a violent crime. He was sentenced to 116 years in prison.
Appeal at the Sixth Circuit
Carpenter appealed his conviction and sentence to the United States Court of Appeals for the Sixth Circuit, arguing that the CSLI evidence used against him should be suppressed because the police had not obtained a warrant pertaining to his CSLI records before searching through them. In 2015, the Circuit Court upheld Carpenter's conviction. This ruling was largely based on the Smith v. Maryland precedent, stating that Carpenter used cellular telephone networks voluntarily, and per the third-party doctrine he had no reasonable expectation that the data should be private. Thus, review of that information by the police did not constitute a "search" and did not require a warrant under the Fourth Amendment.
Carpenter appealed this ruling to the U.S. Supreme Court, which granted certiorari in 2016.
Supreme Court
Twenty amicus curiae briefs were filed by interested organizations, scholars, and corporations for Carpenter's case. Some considered the case to be the most important Fourth Amendment dispute to come before the Supreme Court in a generation. The Court issued its decision in 2018, with the majority opinion written by Chief Justice John Roberts.
The Court's ruling recognized that the Carpenter case revealed a contradiction between two lines of Supreme Court rulings on the matter of police searches of personal communications information. In United States v. Jones (2012) the Court had ruled that GPS tracking could constitute a search under the Fourth Amendment as a violation of a person's reasonable expectation of privacy. Meanwhile, the Court had held in Smith v. Maryland (1979) that the third-party doctrine absolved the government from warrant requirements when searching through telephone records.
Ultimately, in Carpenter the court determined that the third-party doctrine could not be extended to historical cell site location information (CSLI). Instead, the Court compared "detailed, encyclopedic, and effortlessly compiled" CSLI records to the GPS information at issue in United States v. Jones, recognizing that both forms of data accord the government the ability to track individuals' past movements. Furthermore, the Court noted that CSLI could pose even greater privacy risks than GPS data, as the prevalence of cellphones could accord the government "near perfect surveillance" of an individual's movements. Accordingly, the Court ruled that, under the Fourth Amendment, the government must obtain a search warrant in order to access historical CSLI records. Roberts argued that technology "has afforded law enforcement a powerful new tool to carry out its important responsibilities. At the same time, this tool risks Government encroachment of the sort the Framers [of the U.S. Constitution], after consulting the lessons of history, drafted the Fourth Amendment to prevent." As stated in the opinion, "Unlike the nosy neighbor who keeps an eye on comings and goings, they [new technologies] are ever alert, and their memory is nearly infallible. There is a world of difference between the limited types of personal information addressed in Smith [...] and the exhaustive chronicle of location information casually collected by wireless carriers today."
However, Roberts stressed that the Carpenter decision was a very narrow one and did not affect other uses of the third-party doctrine, such as searches of banking records. Similarly, he noted that the decision did not prevent the collection of CSLI without a warrant in cases of emergency or for issues of national security.
Dissenting opinions
Justice Anthony Kennedy, in a dissenting opinion, cautioned against the limitations on law enforcement inherent in the majority opinion. According to Kennedy, the ruling "places undue restrictions on the lawful and necessary enforcement powers exercised not only by the Federal Government, but also by law enforcement in every State and locality throughout the Nation. Adherence to this Court's longstanding precedents and analytic framework would have been the proper and prudent way to resolve this case."
In another dissent, Justice Samuel Alito wrote: "I fear that today's decision will do far more harm than good. The Court's reasoning fractures two fundamental pillars of Fourth Amendment law, and in doing so, it guarantees a blizzard of litigation while threatening many legitimate and valuable investigative practices upon which law enforcement has rightfully come to rely." In yet another dissent, Justice Neil Gorsuch agreed with most of the majority opinion but stressed that CSLI data is personal property, and its storage by telephone companies should be immaterial. According to Gorsuch, the Fourth Amendment "grants you the right to invoke its guarantees whenever one of your protected things (your person, your house, your papers, or your effects) is unreasonably searched or seized. Period." Gorsuch further recommended that the third-party doctrine be overturned as inconsistent with the original meaning of the Fourth Amendment.
Impact and subsequent developments
After the Supreme Court ruling, Carpenter's criminal conviction was remanded to the Sixth Circuit to determine if it could stand without the CSLI data that required a warrant per the Supreme Court. Carpenter's lawyers argued that the data should have been subject to the exclusionary rule and thrown out as material collected without a proper warrant under the Supreme Court's ruling. However, the Circuit Court judges concluded that the FBI was acting in good faith with respect to collecting the data based on the law at the time the crimes were committed. This type of good faith exemption is permitted per another Supreme Court precedent, Davis v. United States (2011). The evidence was allowed to stand, and the Sixth Circuit again upheld Carpenter's criminal conviction and prison sentence. His arguments concerning sentencing procedures under the recently enacted First Step Act were rejected.
The Supreme Court's ruling in Carpenter was narrow and did not otherwise change the third-party doctrine related to other business records that might incidentally reveal location information, nor did it overrule prior decisions concerning conventional surveillance techniques and tools such as security cameras. The Court did not extend its ruling to other matters related to cellphones not presented in Carpenter, including real-time CSLI or "tower dumps" (the downloading of information about all the devices that were connected to a particular cell site during a particular interval). The opinion also did not consider other data collection goals involving foreign affairs or national security.
References
Further reading
External links
Case page at SCOTUSblog
2016 in United States case law
2018 in United States case law
United States Supreme Court cases
United States Fourth Amendment case law
United States Supreme Court cases of the Roberts Court
United States Court of Appeals for the Sixth Circuit cases
Search and seizure case law
Telecommunications case law
Mobile phone culture
2010s in Detroit
Global Positioning System | Carpenter v. United States | Technology,Engineering | 2,143 |
3,238,386 | https://en.wikipedia.org/wiki/Landscape%20planning | Landscape planning is a branch of landscape architecture. According to Erv Zube (1931–2002) landscape planning is defined as an activity concerned with developing landscaping amongst competing land uses while protecting natural processes and significant cultural and natural resources. Park systems and greenways of the type designed by Frederick Law Olmsted are key examples of landscape planning. Landscape designers tend to work for clients who wish to commission construction work. Landscape planners analyze broad issues as well as project characteristics which constrain design projects.
Landscape planners may work on projects which are of broad geographical scope, concern many land uses or many clients or are implemented over a long period of time. As an example, the damage caused by unplanned mineral extraction was one of the early reasons for a public demand for landscape planning.
In Europe
Alberti wrote on the need for town squares for markets and specific implementations to make most use of the space. In North Europe this developed into the idea that residential squares should be planned around green spaces. The first space of this type was the Place des Vosges. Residential squares were also made in Britain and their planning developed into the idea of incorporating public open space (public parks within towns). Frederick Law Olmsted gave momentum to this idea with his proposal for a park systems in Boston - the famous Emerald Necklace. Patrick Abercrombie took up this idea and incorporated it in his great 1943-4 Open Space Plan for the County of London. An example of landscape planning in use is the plans of RWE in the wake of its mining operations and how they plan to use leftover detritus and soil in their re-cultivation efforts to restore the damaged ecosystems and landscapes created by open pit mines (e.g. Garzweiler surface mine).
In the US
In the United States, landscape architects provide landscape planning services focused on the natural environment along with urban planners. But, unlike Canada and Europe, the US does not have a national land use planning system. Frederick Law Olmsted and Ian McHarg are two influential American landscape architects that also worked as planners. McHarg's work on overlay landscape planning contributed to the development of GIS and to the foundation of ESRI by Jack Dangermond.
Legislation
The principles of landscape planning are now incorporated in various types of legislation and policy documents. In America, the National Environmental Policy Act was influenced by the work of Ian McHarg on Environmental impact assessment. In Germany, the Federal Nature Conservation Act requires the preparation of landscape plans. For the Europe Union as a whole, the European Landscape Convention has wide-ranging implications for the design and planning of relationships between development and the landscape. In Asia, major development projects are taking place and illustrating the need for good landscape planning. The Three Gorges Dam, for example, will have extensive impacts on the landscape. They have been planned to a degree but future monitoring of the project is likely to show that better landscape planning and design would have been possible.
Methodology
The conventional planning process is a linear progression of activities. The common steps are:
Identification of problems and opportunities.
Establishment of goals.
Inventory and analysis of the biophysical environment.
Human community inventory and analysis.
Development of concepts and the selection of options.
Adoption of a plan.
Community involvement and education.
Detailed design.
Plan implementation.
Plan administration.
Landscape planning not always means an ecological planning method, for that it must be considered that "planning is a process that uses the scientific and technical information for considering and reaching consensus on a range of choices. Ecology is the study of the relationship of all living things, including people, to their biological and physical environments. Ecological planning then may be defined as the use of biophysical and sociocultural information to suggest opportunities and constraints for decision making about the use of landscape". (Steiner, 1991) While the common steps are listed above, the process of Landscape planning is adaptable to many situations and is useful in many ways depending on the goals for which it is used.
Impacts and implications
Results of proper implementations of landscape planning practices are not only limited to more functional landscapes. It can also influence for the better many aspects of the environment and community in which it is used to its potential. While the chief purpose of landscape planning is for ecological reasons it can impact so much more when used effectively as a tool.
Ecology
Landscape planning is mainly used for ecological purposes and functions best when the result of the planning process is the least amount of interruption of ecological factors from before the implementation ever went into place. In this practice landscape planning can be used to not only maintain the status of the existing environment, but also can be used to improve aspects of previously under performing ecosystems, for example, designing to increase biodiversity. For example Landscape planning could be used to create additional habitat for endangered species, and reclamation of previously used or depleted lands (e.g. old agricultural spaces) for expansion of natural ecosystems. This also includes planning in order to reduce the impact of the changes to the environment. with proper landscape planning, a greater speed of recovery for the ecosystems of interrupted spaces is achievable.
Health
Similar to the impacts of healing gardens, the positive healing effects of proper implementations of planned landscapes are of great benefit. When people are exposed to nature, they would find that their overall mood had improved and that they recover from stress and illness at an accelerated rate. With the proper use of landscape planning, health within an urban leaning environment in regards to stress and recovery can be greatly improved above the unplanned alternative. When landscape planning is used to properly conserve ecological systems that may have been displaced, it makes it so recreational use of the environment is maintained while conserving the systems for people to enjoy.
Use of other technologies in context
The development of GIS technology such as those developed by ESRI, have great import to the practice of Landscape planning. Use of assisting technology allows for the conditions and factors existing in a landscape to be easily aggregated and analyzed. Through the use of GIS technology you are able to answer many of the questions about a landscape that is in question. such as, "how functional is this landscape?" or "to what extent do the factors outside of the site affect the planning that needs to be done?" The use of technology that is developing with greater and greater accuracy has the ability to make sustainable developments easier and more common across the globe.
See also
Footnotes
Landscape planning education in America: retrospect and prospect
Ecological design and planning George F. Thompson and Frederick R. Steiner, (Wiley, 1997)
Landscape planning : an introduction to theory and practice Hackett, Brian (Oriel, 1971)
Landscape planning and environmental impact design Tom Turner (2nd ed UCL Press, 1998)
Design with nature Ian L. McHarg ( Wiley, 1992)
The living landscape: an ecological approach to landscape planning Steiner, Frederick R. (McGraw-Hill College, 1991)
References
External links
European Landscape Convention (official statement by the Council of Europe).
Landscape
Landscape architecture
Environmental design
Sustainable design | Landscape planning | Engineering | 1,413 |
20,415,389 | https://en.wikipedia.org/wiki/Ontogenetic%20parade | In developmental psychology, the ontogenetic parade is the term introduced by Isaac Marks for the predictable pattern of the development of normal childhood fears: emergence, plateau, and decline.
References
Developmental psychology
Fear | Ontogenetic parade | Biology | 41 |
26,527,537 | https://en.wikipedia.org/wiki/Drawbar%20pull | In automotive engineering, drawbar pull is the amount of horizontal force available to a vehicle at the drawbar for accelerating or pulling a load.
Drawbar pull is a function of velocity, and in general decreases as the speed of the vehicle increases (due both to increasing resistance and decreasing transmission gear ratios). Drawbar pull is the difference between tractive effort available and tractive effort required to overcome resistance at a specified speed.
Drawbar pull data for a vehicle is usually determined by measuring the amount of available tractive force using a dynamometer, and then combining that data with coastdown data to obtain the available drawbar pull force at each speed.
References
Automotive engineering | Drawbar pull | Engineering | 135 |
1,877,692 | https://en.wikipedia.org/wiki/Latten | Historically, the term "latten" referred loosely to the copper alloys such as brass
or bronze
that appeared in the Middle Ages and through to the late-18th and early-19th centuries. Such alloys were used for monumental brasses, in decorative effects on borders, rivets or other details of metalwork (particularly armour), in livery and pilgrim badges or funerary effigies. Latten commonly contained varying amounts of copper, tin, zinc and lead, giving it characteristics of both brass and bronze. Metalworkers commonly formed latten in thin sheets and used it to make church utensils. Brass of this period is made through the calamine brass process, from copper and zinc ore. (Later brass was made with zinc metal from Champion's smelting process and is not generally referred to as "latten".) This calamine brass was generally manufactured as hammered sheet or "battery brass" (hammered by a "battery" of water-powered trip hammers), and cast brass was rare.
"Latten" also refers to a type of tin plating on iron (or possibly some other base metal), which is known as white latten; and black latten refers to laten-brass, which is brass milled into thin plates or sheets.
The term "latten" has also been used, rarely, to refer to lead alloys.
In general, metal in thin sheets is characterised as "latten", e.g. gold latten, and lattens (plural) refers to metal sheets between 1/64" and 1/32" in thickness.
Footnotes
References
Random House Webster's Unabridged Dictionary (1998, 2nd edition)
The Oxford English Dictionary (1989, 2nd edition)
Webster's Third New International Dictionary (1986)
Copper alloys
Brass | Latten | Chemistry | 372 |
57,769,133 | https://en.wikipedia.org/wiki/Close%20Coupled%20Cooling | Close Coupled Cooling is a last generation cooling system particularly used in data centers. The goal of close coupled cooling is to bring heat transfer closest to its source: the equipment rack. By moving the air conditioner closer to the equipment rack a more precise delivery of inlet air and a more immediate capture of exhaust air is ensured.
Air Conditioner Types
Commercially available close coupled solutions can be divided into two categories: Open-Loop and Closed-Loop.
Open-Loop Configuration
Open-Loop configurations are not totally independent from the room they are installed, and air flows interact with the ambient room environment.
In-Row Air Conditioners
Row-Based Air Conditioning units are installed inside the rack rows. Air flows generally follow short and linear paths, reducing, in this way, the necessary power needed to start up the fans and increasing the energy efficiency.
A Row-Based cooling solution offers one advantage with respect to the Room-Based solution, since the former one can be better adapted to the needs of cooling for specific rows; it is anyway appropriate not to locate the conditioning units at the beginning or at the end of the rows to maximise their performance.
Rear Door Heat Exchangers
This type of solution is based on the substitution of the rear door of an existing rack.
These heat exchangers leverage the front-to-back air dissipation of most of the IT equipments: the servers dissipate warm air, which passes the heat exchanger coil and is returned to the room at an agreeable temperature.
The cooling units of this category do not occupy additional space, so they are particularly indicated either to cool all the spaces originally designed as data centers, or to integrate an already existing cooling system.
Overhead Heat Exchangers
Generally, a heat exchanger of this type discharges air from the ceiling into the cold aisle whereas the exhaust air rises into the vents in the ceiling; in Close Coupled system cases, the units are positioned directly above the servers, making the cold air delivery and hot air return much more precise.
A system of this type, being positioned vertically, does not need further floor space in the room.
Closed-Loop Configuration
The Closed-Loop cooling typologies act independently from the room they are installed; the rack and the heat exchanger work exclusively with one another, creating an internal microclimate.
In Rack Cooling
The cooling system is adjoint to the server rack and both of them are completely sealed; the solid doors on the enclosure and In-Row Air Conditioners contain the air flow, directing cold air to the server inlet and exhaust air, by using fans, through the cooling coil.
The Close-Loop design allows a very focused cooling at rack level and it is possible to install very dense equipment disregarding the ambient environment, giving flexibility to use unconventional spaces to install the IT equipment.
Efficiency
In the traditional layout, the fans must move air from the perimeter of the room, under the raised floor, and through a perforated floor tile into servers intake. This process requires energy, that varies depending on the typology of the structure. Often, under the raised floor, holdbacks (large cable bundles, conduits) exist, requiring additional fan energy to move the required cold air volume.
Being that in Close Coupled solutions the cooling system and the equipment rack are close to one another, the energy needed is reduced. With an In-Row typology the cooling unit is incorporated in the row of racks and, providing air directly to the row, there are not impediments to consider under the floor. It is estimated, that when integrated, a Close Coupled system can guarantee up to 95% of annual energy reduction compared to a traditional CRAC system of equal cooling capacity.
Some cooling typologies can be associated to fans with variable velocity that adapt in better ways to the workload, so also to the internal temperature of the rack. Having fans that work at the minimum velocity satisfying the requirements of the Data Center is very important for energy consumption.
It is verified that the percentage of energy saved, hence the total energy cost decreases in a more than proportional way with respect to the decrease of air flow (for example, by reducing the fan velocity by 10% we save 27% of energy).
Efficiency is also represented by modularity. With a Close Coupled solution in is indeed possible adding new conditioners in forecast of an increase of the Data Centre capacity.
Despite the fact that some past studies have speculated a very elevated growth of sales of Close Coupled solutions, more recent studies have instead shown a more contained growth. The reason seems to be due to the fact that the In-Row solutions offer significant energy savings as the rack densities are close to the 8-10 kW threshold; today's average densities for medium-sized data centers are instead about 5 kW and energy savings do not fully justify the higher cost of investment for the cooling system.
Refrigerated Water Temperatures
In traditional systems, the refrigerated water supply temperatures typically vary between 6 and 7 °C and cold water is in fact necessary to generate cold air that compensates for the rise that occurs on the floor of the data center, since the cold inlet air and the hot exhaust air interact. However, it is necessary to ensure that the inlet temperature is between 18 and 26.5 °C as established by the ASHRAE.
Some types of Close Coupled systems allow warmer water inlet temperatures due to the proximity of the refrigeration system and the design of the cooling coil while remaining within the guidelines of the ASHRAE.
Since the refrigerators represent 30-40% of the energy consumption of a data center and that this is largely due to mechanical refrigeration, a higher water inlet temperature allows increase the hours in which free cooling is possible and therefore increase the efficiency of the refrigerator.
Close Coupled system of Google Data Centers
For several years now, Google, according to the statements of the vice president of Data Centers, Joseph Kava, restructures the cooling system of its Data Centers every 12 – 18 months, also focusing on Close Coupled type systems.
In 2012 Google published a photo gallery that shows the design of its cooling system, followed by an explanation of Data Center Vice President Joseph Kava, of how it works.
In the data center shown the rooms serve as cold corridors, there is a raised floor but there are no perforated tiles. Cooling occurs in closed corridors with rows of racks on both sides while cooling coils using cold water serve as the ceiling of these warm corridors, which also house the pipes that carry the water to and from the cooling towers housed in another part of the building.
The temperature of the air is generally maintained around 26.5 °C, getting warmer more and more due to the contact with various components, up to about 49 °C. When air is directed by fans in the warm closed corridor where, reaching the top of the room passes through the cooling coil and is cooled to room temperature. The flexible piping connects to the cooling coil at the top of the hot aisle and descends through an opening in the floor and flows under the raised floor.
From the statements of Kava "If we had leaks in the conduits, the water would sink down into our raised floor. We have a lot of experience with this design, and it has never happened a large water loss" , the presence of an emergency system for any water leaks is confirmed. It is also confirmed that the proximity of liquids to the servers is not considered problematic.
Kava also stated, referring to other types of cooling systems with installations on the ceiling to return the hot exhaust air to the air conditioners of the computer room (CRAC) located along the perimeter of the raised floor area, that The whole system is inefficient because the hot air is moved over a long distance while traveling towards the "CRAC", while a Close Coupled system is significantly more efficient.
Bibliography
Bean, J., & Dunlap, K. (2008), Energy Efficient Data Centers: A Close-coupled Row Solution, ASHRAE Journal , 34-40.
EPA. (2007, Agosto 2), EPA Report to Congress on Server and Data Center Energy Efficiency, da Energy Star.
EYP Mission Critical Facilities. (2006, Luglio 26). Energy Intensive Buildings Trends and Solutions: Data Centers , da Critical Facilities Roundtable.
Fontecchio, M. (2009, Gennaio 21), Data Center Air Conditioning Fans Blow Savings Your Way, da Search Data Center.
Sun Microsystems (2008), Energy Efficient Data Centers: The Role of Modularity in Data Center Design, Sun Microsystems.
Notes
DataCenterKnowledge
Cabling install
Close coupled cooling market
External links
How google cools its armada of servers
Metrics and efficiency the future of data centers
Close coupled cooling market
Close-coupled cooling
Data centers | Close Coupled Cooling | Technology | 1,786 |
44,937,193 | https://en.wikipedia.org/wiki/Association%20of%20Swedish%20Engineering%20Industries | The Technology Industries of Sweden () is a Swedish trade organization representing employers of multinational engineering and industrial manufacturing companies. The member companies operate in a range of sectors that include telecommunications, fabricated metal products, electronics, machinery and equipment, office machinery and apparatus, power industry, instrument technology, optics, motor cars and transport equipments.
The association's main objective is to assist the employers of its member companies with various industry policies and labor law guidelines, collective agreement negotiations with labor unions as well as regular publication of economic policy and trend analysis reports. The association also maintains an established task force to promote initiatives in technological innovation, research collaboration between universities and companies as well as design thinking that ultimately can enhance the global competitiveness of Sweden's industrial sector. The association has 4,500 member companies with over 300,000 employees.
History
In July 1896, as a result of the rapid industrial clustering and labor unionization, an industrial worker association (Swedish: Sveriges Verkstadsförening) was founded in Gothenburg, the home of world headquarters for several Swedish multinational engineering companies including, Electrolux, Saab Group, Volvo Group as well as SKF. The purpose of Verkstadsförening was to promote healthy employer-employee relations through collaboration with labor unions and to design bilateral employment agreements providing equal and yet competitive employment conditions to manufacturing employees.
Verkstadsförening subsequently expanded through several regional organizations across the country, which by 1917 together became members of the Swedish Employer's Association (Swedish: Svenska Arbetsgivareföreningen (SAF)). The pivotal change however took place in 1992 when the Workshop Association merged with the Mechanic Federation (Swedish: Mekanförbundet), yet another employer's interest organization for select sectors of the ever industrializing manufacturing sector in Sweden. The combined organizations were then named The Association of Swedish Workshop Industries (Swedish: Föreningen Sveriges Verkstadsindustrier (VI)), which in 2002 was renamed to the current Association of Swedish Engineering Industries.
The Grand Award of Design
Since 2003, the association has hosted an annual challenge named The Grand Award of Design (Swedish: Stora Designpriset) to cultivate and promote domestic industrial design and design thinking for product and service development. The key objective is to nurture and inspire design work of viable commercial and competitive value for the Swedish manufacturing companies. Each year a shortlist of finalist companies are nominated for The Grand Design Prize and awarded with grants.
Affiliations
At a national level, the association is a member of the Confederation of Swedish Enterprise (Swedish: Svenskt Näringsliv). At a regional level, the association is a member of the European Engineering Association named Orgalime where collaborative partnerships have been formed at an EU-level R&D workgroups to increase cross-border collaboration in technology innovation in the manufacturing sector.
References
Organizations based in Stockholm
2002 establishments in Sweden
Engineering organizations | Association of Swedish Engineering Industries | Engineering | 597 |
62,067,745 | https://en.wikipedia.org/wiki/Visiting%20the%20sick | Visiting the sick, either at hospital or their home, is a recommended philanthropic deed in different cultures and religions, including Christianity, Judaism and Islam and is considered an aspect of benevolence and a work of mercy.
In Judaism, for instance, the act is called bikur cholim and is considered a part of mitzvah (commandment). In Christianity it may be done by relatives or friends or formally by a chaplain or minister.
Format
Visiting the sick is mainly performed on a voluntarily basis. The purpose of the visit is to reflect on shared feeling with the sick person and to spend some warm quality time with them, providing them with inspiration and positive feelings that can help them fight their sickness and get well soon.
See also
Anointing of the sick
References
Philanthropy
Commandments | Visiting the sick | Biology | 160 |
11,123 | https://en.wikipedia.org/wiki/Fornax | Fornax () is a constellation in the southern celestial hemisphere, partly ringed by the celestial river Eridanus. Its name is Latin for furnace. It was named by French astronomer Nicolas Louis de Lacaille in 1756. Fornax is one of the 88 modern constellations.
The three brightest stars—Alpha, Beta and Nu Fornacis—form a flattened triangle facing south. With an apparent magnitude of 3.91, Alpha Fornacis is the brightest star in Fornax. Six star systems have been found to have exoplanets. The Fornax Dwarf galaxy is a small faint satellite galaxy of the Milky Way. NGC 1316 is a relatively close radio galaxy.
The Hubble's Ultra-Deep Field is located within the Fornax constellation.
It is the 41st largest constellation in the night-sky, occupying an area of 398 square degrees. It is located in the first quadrant of the southern hemisphere (SQ1) and can be seen at latitudes between +50° and -90° during the month of December.
History
The French astronomer Nicolas Louis de Lacaille first described the constellation in French as le Fourneau Chymique (the Chemical Furnace) with an alembic and receiver in his early catalogue, before abbreviating it to le Fourneau on his planisphere in 1752, after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that symbolised the Age of Enlightenment. Lacaille Latinised the name to Fornax Chimiae on his 1763 chart.
Characteristics
The constellation Eridanus borders Fornax to the east, north and south, while Cetus, Sculptor and Phoenix gird it to the north, west and south respectively. Covering 397.5 square degrees and 0.964% of the night sky, it ranks 41st of the 88 constellations in size, The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "For". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 8 segments (illustrated in infobox). In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between −23.76° and −39.58°. The whole constellation is visible to observers south of latitude 50°N.
Features
Stars
Lacaille gave Bayer designations to 27 stars now named Alpha to Omega Fornacis, labelling two stars 3.5 degrees apart as Gamma, three stars Eta, two stars Iota, two Lambda and three Chi. Phi Fornacis was added by Gould, and Theta and Omicron were dropped by Gould and Baily respectively. Upsilon, too, was later found to be two stars and designated as such. Overall, there are 59 stars within the constellation's borders brighter than or equal to apparent magnitude 6.5. However, there are no stars brighter than the fourth magnitude.
The three brightest stars form a flattish triangle, with Alpha (also called Dalim) and Nu Fornacis marking its eastern and western points and Beta Fornacis marking the shallow southern apex. Originally designated 12 Eridani by John Flamsteed, Alpha Fornacis was named by Lacaille as the brightest star in the new constellation. It is a binary star that can be resolved by small amateur telescopes. With an apparent magnitude of 3.91, the primary is a yellow-white subgiant 1.21 times as massive as the Sun that has begun to cool and expand after exhausting its core hydrogen, having swollen to 1.9 times the Sun's radius. Of magnitude 6.5, the secondary star is 0.78 times as massive as the Sun. It has been identified as a blue straggler, and has either accumulated material from, or merged with, a third star in the past. It is a strong source of X-rays. The pair is 46.4 ± 0.3 light-years distant from Earth.
Beta Fornacis is a yellow-hued giant star of spectral type G8IIIb of magnitude 4.5 that has cooled and swelled to 11 times the Sun's diameter, 178 ± 2 light-years from Earth. It is a red clump giant, which means it has undergone helium flash and is currently generating energy through the fusion of helium at its core.
Nu Fornacis is 370 ± 10 light-years distant from Earth. It is a blue giant star of spectral type B9.5IIIspSi that is 3.65 ± 0.18 times as massive and around 245 times as luminous as the Sun, with 3.2 ± 0.4 times its diameter. It varies in luminosity over a period of 1.89 days—the same as its rotational period. This is because of differences in abundances of metals in its atmosphere; it belongs to a class of star known as an Alpha2 Canum Venaticorum variable.
Shining with an apparent magnitude of 5.89, Epsilon Fornacis is a binary star system located 104.4 ± 0.3 light-years distant from Earth. Its component stars orbit each other every 37 years. The primary star is around 12 billion years old and has cooled and expanded to 2.53 times the diameter of the Sun, while having only 91% of its mass.
Omega Fornacis is a binary star system composed of a blue main-sequence star of spectral type B9.5V and magnitude 4.96, and a white main sequence star of spectral type A7V and magnitude 7.88. The system is 470 ± 10 light-years distant from Earth.
Kappa Fornacis is a triple star system composed of a yellow giant and a pair of red dwarfs.
R Fornacis is a long-period variable and carbon star.
LP 944-20 is a brown dwarf of spectral type M9 that has around 7% the mass of the Sun. Approximately 21 light-years distant from Earth, it is a faint object with an apparent magnitude of 18.69. Observations published in 2007 showed that the atmosphere of LP 944-20 contains much lithium and that it has dusty clouds. Smaller and less luminous still is 2MASS 0243-2453, a T-type brown dwarf of spectral type T6. With a surface temperature of 1040–1100 K, it has 2.4–4.1% the mass of the Sun, a diameter 9.2 to 10.6% of that of the Sun, and an age of 0.4–1.7 billion years.
Six star systems in Fornax have been found to have planets:
Lambda2 Fornacis is a star about 1.2 times as massive as the Sun with a planet about as massive as Neptune, discovered by doppler spectroscopy in 2009. The planet has an orbit of around 17.24 days.
HD 20868 is an orange dwarf with a mass around 78% that of the Sun, 151 ± 10 light-years away from Earth. It was found to have an orbiting planet approximately double the mass of Jupiter with a period of 380 days.
WASP-72 is a star around 1.4 times as massive that has begun to cool and expand off the main sequence, reaching double the Sun's diameter. It has a planet around as massive as Jupiter orbiting it every 2.2 days.
HD 20781 and HD 20782 are a pair of sunlike yellow main sequence stars that orbit each other. Each has been found to have planets.
HR 858 is a near naked eye visible star in Fornax, 31.3 parsecs away. In May 2019, it was announced to have at least 3 exoplanets as observed by transit method of the Transiting Exoplanet Survey Satellite.
Deep-sky objects
Local Group
NGC 1049 is a globular cluster 500,000 light-years from Earth. It is in the Fornax Dwarf Galaxy. NGC 1360 is a planetary nebula in Fornax with a magnitude of approximately 9.0, 1,280 light-years from Earth. Its central star is of magnitude 11.4, an unusually bright specimen. It is five times the size of the famed Ring Nebula in Lyra at 6.5 arcminutes. Unlike the Ring Nebula, NGC 1360 is clearly elliptical.
The Fornax Dwarf galaxy is a dwarf galaxy that is part of the Local Group of galaxies. It is not visible in amateur telescopes, despite its relatively small distance of 500,000 light-years.
Helmi stream is a small galactic stream in Fornax. This small galaxy was destroyed by Milky Way 6 billion years ago. There was candidate for extragalactic planet, HIP 13044 b.
Outside
NGC 1097 is a barred spiral galaxy in Fornax, about 45 million light-years from Earth. At magnitude 9, it is visible in medium amateur telescopes. It is notable as a Seyfert galaxy with strong spectral emissions indicating ionized gases and a central supermassive black hole.
Fornax Cluster
The Fornax Cluster is a cluster of galaxies lying at a distance of 19 megaparsecs (62 million light-years). It is the second richest galaxy cluster within 100 million light-years, after the considerably larger Virgo Cluster, and may be associated with the nearby Eridanus Group. It lies primarily in the constellation Fornax, with its southern boundaries partially crossing into the constellation of Eridanus, and covers an area of sky about 6° across or about 28 sq degrees. The Fornax cluster is a part of larger Fornax Wall. Down are some famous objects in this cluster:
NGC 1365 is another barred spiral galaxy located at a distance of 56 million light-years from Earth. Like NGC 1097, it is also a Seyfert galaxy. Its bar is a center of star formation and shows extensions of the spiral arms' dust lanes. The bright nucleus indicates the presence of an active galactic nucleus – a galaxy with a supermassive black hole at the center, accreting matter from the bar. It is a 10th magnitude galaxy associated with the Fornax Cluster.
Fornax A is a radio galaxy with extensive radio lobes that corresponds to the optical galaxy NGC 1316, a 9th-magnitude galaxy. One of the closer active galaxies to Earth at a distance of 62 million light-years, Fornax A appears in the optical spectrum as a large elliptical galaxy with dust lanes near its core. These dust lanes have caused astronomers to discern that it recently merged with a small spiral galaxy. Because it has a high rate of type Ia supernovae, NGC 1316 has been used to determine the size of the universe. The jets producing the radio lobes are not particularly powerful, giving the lobes a more diffuse, knotted structure due to interactions with the intergalactic medium. Associated with this peculiar galaxy is an entire cluster of galaxies.
NGC 1399 is a large elliptical galaxy in the Southern constellation Fornax, the central galaxy in the Fornax cluster.
The galaxy is 66 million light-years away from Earth. With a diameter of 130 000 light-years, it is one of the largest galaxies in the Fornax cluster and slightly larger than Milky Way. William Herschel discovered this galaxy on October 22, 1835.
NGC 1386 is a spiral galaxy located in the constellation Eridanus. It is located at a distance of circa 53 million light years from Earth and has apparent dimensions of 3.89' x 1.349'. It is a Seyfert galaxy, the only one in Fornax Cluster.
NGC 1427A is an irregular galaxy in the constellation Eridanus. Its distance modulus has been estimated using the globular cluster luminosity function to be 31.01 ± 0.21 which is about 52 Mly. It is the brightest dwarf irregular member of the Fornax cluster and is in the foreground of the cluster's central galaxy NGC 1399.
NGC 1460 is a barred lenticular galaxy in the constellation Eridanus. It was discovered by John Herschel on November 28, 1837. It is moving away from the Milky Way 1341 km/s. NGC 1460 has a Hubble classification of SB0, which indicates it is a barred lenticular galaxy. But, this one contains a huge bar at its core. The bar is spreading from center to the edge of the galaxy, as seen on Hubble image in the box. This bar is one of the largest seen in barred lenticular galaxies.
There are also first ultracompact dwarf galaxies discovered.
Distant universe
Fornax has been the target of investigations into the furthest reaches of the universe. The Hubble Ultra Deep Field is located within Fornax, and the Fornax Cluster, a small cluster of galaxies, lies primarily within Fornax. At a meeting of the Royal Astronomical Society in Britain, a team from University of Queensland described 40 unknown "dwarf" galaxies in this constellation; follow-up observations with the Hubble Space Telescope and the European Southern Observatory's Very Large Telescope revealed that ultra compact dwarfs are much smaller than previously known dwarf galaxies, about across.
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UDFj-39546284 is a candidate protogalaxy located in Fornax, although recent analyses have suggested it is likely to be a lower redshift source.
GRB 190114C was a notable gamma ray burst explosion from a galaxy 4.5 billion light years away near the Fornax constellation, that was initially detected in January 2019. According to astronomers, "the brightest light ever seen from Earth [to date] ... [the] biggest explosion in the Universe since the Big Bang".
Equivalents
In Chinese astronomy, the stars that correspond to Fornax are within the White Tiger of the West (西方白虎, Xī Fāng Bái Hǔ).
See also
Fornax (Chinese astronomy)
Notes
References
Cited texts
Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. . Princeton University Press, Princeton. .
External links
The Deep Photographic Guide to the Constellations: Fornax
Starry Night Photography – Fornax Constellation
The clickable Fornax
Southern constellations
Constellations listed by Lacaille | Fornax | Astronomy | 2,982 |
70,182,860 | https://en.wikipedia.org/wiki/11%20Sagittae | 11 Sagittae is a blue in the constellation Sagitta with a spectral type of B9III.
Naming
It is in the Chinese asterism (), or Left Flag which consists of 11 Sagittae, γ Sagittae, α Sagittae, β Sagittae, δ Sagittae, ζ Sagittae, 13 Sagittae, 14 Sagittae and ρ Aquilae. Consequently, the Chinese name for γ Sagittae itself is (, ).
References
B-type giants
Sagitta
Sagittae, 11
189090
7622
098324 | 11 Sagittae | Astronomy | 135 |
166,803 | https://en.wikipedia.org/wiki/Shutter%20speed | In photography, shutter speed or exposure time is the length of time that the film or digital sensor inside the camera is exposed to light (that is, when the camera's shutter is open) when taking a photograph.
The amount of light that reaches the film or image sensor is proportional to the exposure time. of a second will let half as much light in as .
Introduction
The camera's shutter speed, the lens's aperture or f-stop, and the scene's luminance together determine the amount of light that reaches the film or sensor (the exposure). Exposure value (EV) is a quantity that accounts for the shutter speed and the f-number. Once the sensitivity to light of the recording surface (either film or sensor) is set in numbers expressed in "ISOs" (e.g. 200 ISO, 400 ISO), the light emitted by the scene photographed can be controlled through aperture and shutter-speed to match the film or sensor sensitivity to light. This will achieve a good exposure when all the details of the scene are legible on the photograph. Too much light let into the camera results in an overly pale image (or "over-exposure") while too little light will result in an overly dark image (or "under-exposure").
Multiple combinations of shutter speed and f-number can give the same exposure value (E.V.). According to exposure value formula, doubling the exposure time doubles the amount of light (subtracts 1 EV). Reducing the aperture size at multiples of one over the square root of two lets half as much light into the camera, usually at a predefined scale of , , , , , , , , , , and so on. For example, lets four times more light into the camera as does. A shutter speed of s with an aperture gives the same exposure value as a s shutter speed with an aperture, and also the same exposure value as a s shutter speed with an aperture, or s at .
In addition to its effect on exposure, the shutter speed changes the way movement appears in photographs. Very short shutter speeds can be used to freeze fast-moving subjects, for example at sporting events. Very long shutter speeds are used to intentionally blur a moving subject for effect. Short exposure times are sometimes called "fast", and long exposure times "slow".
Adjustments to the aperture need to be compensated by changes of the shutter speed to keep the same (right) exposure.
In early days of photography, available shutter speeds were not standardized, though a typical sequence might have been s, s, s, s, s and s; neither were apertures or film sensitivity (at least 3 different national standards existed). Soon this problem resulted in a solution consisting in the adoption of a standardized way of choosing aperture so that each major step exactly doubled or halved the amount of light entering the camera (, , , , , , etc.), a standardized 2:1 scale was adopted for shutter speed so that opening one aperture stop and reducing the amount of time of the shutter speed by one step resulted in the identical exposure. The agreed standards for shutter speeds are: .
With this scale, each increment roughly doubles the amount of light (longer time) or halves it (shorter time).
Camera shutters often include one or two other settings for making very long exposures:
B (for bulb) keeps the shutter open as long as the shutter release is held.
T (for time) keeps the shutter open (once the shutter-release button had been depressed) until the shutter release is pressed again.
The ability of the photographer to take images without noticeable blurring by camera movement is an important parameter in the choice of the slowest possible shutter speed for a handheld camera. The rough guide used by most 35 mm photographers is that the slowest shutter speed that can be used easily without much blur due to camera shake is the shutter speed numerically closest to the lens focal length. For example, for handheld use of a 35 mm camera with a 50 mm normal lens, the closest shutter speed is s (closest to "50"), while for a 200 mm lens it is recommended not to choose shutter speeds below s. This rule can be augmented with knowledge of the intended application for the photograph, an image intended for significant enlargement and closeup viewing would require faster shutter speeds to avoid obvious blur. Through practice and special techniques such as bracing the camera, arms, or body to minimize camera movement, using a monopod or a tripod, slower shutter speeds can be used without blur. If a shutter speed is too slow for hand holding, a camera support, usually a tripod, must be used. Image stabilization on digital cameras or lenses can often permit the use of shutter speeds 3–4 stops slower (exposures 8–16 times longer).
Shutter priority refers to a shooting mode used in cameras. It allows the photographer to choose a shutter speed setting and allow the camera to decide the correct aperture. This is sometimes referred to as Shutter Speed Priority Auto Exposure, or TV (time value on Canon cameras) mode, S mode on Nikons and most other brands.
Creative utility in photography
Shutter speed is one of several methods used to control the amount of light recorded by the camera's digital sensor or film. It is also used to manipulate the visual effects of the final image.
Slower shutter speeds are often selected to suggest the movement of an object in a still photograph.
Excessively fast shutter speeds can cause a moving subject to appear unnaturally frozen. For instance, a running person may be caught with both feet in the air with all indication of movement lost in the frozen moment.
When a slower shutter speed is selected, a longer time passes from the moment the shutter opens till the moment it closes. More time is available for movement in the subject to be recorded by the camera as a blur.
A slightly slower shutter speed will allow the photographer to introduce an element of blur, either in the subject, where, in our example, the feet, which are the fastest moving element in the frame, might be blurred while the rest remains sharp; or if the camera is panned to follow a moving subject, the background is blurred while the subject remains relatively sharp.
The exact point at which the background or subject will start to blur depends on the speed at which the object is moving, the angle that the object is moving in relation to the camera, the distance it is from the camera and the focal length of the lens in relation to the size of the digital sensor or film.
When slower shutter-speeds, in excess of about half a second, are used on running water, the water in the photo will have a ghostly white appearance reminiscent of fog. This effect can be used in landscape photography.
Zoom burst is a technique which entails the variation of the focal length of a zoom lens during a longer exposure. In the moment that the shutter is opened, the lens is zoomed in, changing the focal length during the exposure. The center of the image remains sharp, while the details away from the center form a radial blur, which causes a strong visual effect, forcing the eye into the center of the image.
The following list provides an overview of common photographic uses for standard shutter speeds.
s and less: The fastest speed available in APS-H or APS-C format DSLR cameras (). (Canon EOS 1D, Nikon D1, Nikon 1 J2, D1X, and D1H)
s: The fastest speed available in any 35 mm film SLR camera. (Minolta Maxxum 9xi, s: The fastest speed available in production SLR cameras (), also the fastest speed available in any full-frame DSLR or SLT camera (). Used to take sharp photographs of very fast subjects, such as birds or planes, under good lighting conditions, with an ISO speed of 1,000 or more and a large-aperture lens.
s: The fastest speed available in consumer SLR cameras (); also the fastest speed available in any leaf shutter camera (such as the Sony Cyber-shot DSC-RX1) (). Used to take sharp photographs of fast subjects, such as athletes or vehicles, under good lighting conditions and with an ISO setting of up to 800.
s and s: Used to take sharp photographs of moderately fast subjects under normal lighting conditions.
s and s: Used to take sharp photographs of people in motion in everyday situations. s is the fastest speed useful for panning; it also allows for a smaller aperture (up to ) in motion shots, and hence for a greater depth of field.
s: This speed, and slower ones, are no longer useful for freezing motion. s is used to obtain greater depth of field and overall sharpness in landscape photography, and is also often used for panning shots.
s: Used for panning shots, for images taken under dim lighting conditions, and for available light portraits.
s: Used for panning subjects moving slower than and for available-light photography. Images taken at this and slower speeds normally require a tripod or an image stabilized lens/camera to be sharp.
s and s: This and slower speeds are useful for photographs other than panning shots where motion blur is employed for deliberate effect, or for taking sharp photographs of immobile subjects under bad lighting conditions with a tripod-supported camera.
s, s and 1 s: Also mainly used for motion blur effects and/or low-light photography, but only practical with a tripod-supported camera.
B (bulb) (fraction of second to several hours): Used with a mechanically fixed camera in astrophotography and for certain special effects.
Cinematographic shutter formula
Motion picture cameras used in traditional film cinematography employ a mechanical rotating shutter. The shutter rotation is synchronized with film being pulled through the gate, hence shutter speed is a function of the frame rate and shutter angle.
Where E = shutter speed (reciprocal of exposure time in seconds), F = frames per second, and S = shutter angle:
, for E'' in reciprocal seconds
With a traditional shutter angle of 180°, film is exposed for second at 24 frame/s. To avoid effect of light interference when shooting under artificial lights or when shooting television screens and computer monitors, s (172.8°) or s (144°) shutter is often used.
Electronic video cameras do not have mechanical shutters and allow setting shutter speed directly in time units. Professional video cameras often allow selecting shutter speed in terms of shutter angle instead of time units, especially those that are capable of overcranking or undercranking.
See also
Exposure (photography)
Exposure value
F-number
Shutter (photography)
Preferred number
References
Sources
Science of photography
Durations | Shutter speed | Physics | 2,195 |
75,656,839 | https://en.wikipedia.org/wiki/IBM%20Osprey | IBM Osprey is a 433-qubit quantum processor created by IBM, revealed during the IBM Quantum Summit 2022, which occurred on November 9, 2022, in New York, United States.
It is 3 times larger than its predecessor, the IBM Eagle.
It needs to be cooled down to a temperature of ~0.02 K (-273.13 °C).
References
Quantum computing
IBM microprocessors | IBM Osprey | Technology | 89 |
12,819,244 | https://en.wikipedia.org/wiki/Spermine%20synthase | Spermine synthase (, spermidine aminopropyltransferase, spermine synthetase) is an enzyme that converts spermidine into spermine. This enzyme catalyses the following chemical reaction
S-adenosylmethioninamine + spermidine S-methyl-5'-thioadenosine + spermine
Spermine synthase is an enzyme involved in polyamine biosynthesis. It is present in all eukaryotes and plays a role in a variety of biological functions in plants Its structure consists of two identical monomers of 41 kDa with three domains each, creating a homodimer formed via dimerization. The interactions between one of the three domains, the N-terminals of the monomers, is responsible for dimerization as that is where the active site is located; the central terminal consisting of four β- strands structurally forming a lid for the third domain, the C-terminal domain.
References
External links
EC 2.5.1 | Spermine synthase | Chemistry,Biology | 206 |
68,714,225 | https://en.wikipedia.org/wiki/Bis%28trifluoromethyl%29%20disulfide | Bis(trifluoromethyl) disulfide (TFD) is a fluorinated organosulfur compound that was used as a fumigant. It is also an intermediate in the synthesis of triflic acid. It is a volatile liquid that is extremely toxic by inhalation.
Synthesis
TFD can be produced by reaction of perchloromethyl mercaptan or thiophosgene with sodium fluoride.
Toxicity
TFD is extremely toxic by inhalation. TFD is a powerful pulmonary agent that can cause severe pulmonary edema. TFD is about half as toxic as perfluoroisobutene.
See also
Dimethyl(trifluoromethylthio)arsine
Perchloromethyl mercaptan
Thiophosgene
Perfluoroisobutene
Phosgene
References
Organic disulfides
Trifluoromethylthio compounds
Pulmonary agents
Fumigants | Bis(trifluoromethyl) disulfide | Chemistry | 208 |
4,995,149 | https://en.wikipedia.org/wiki/Forensic%20electrical%20engineering | Forensic electrical engineering is a branch of forensic engineering, and is concerned with investigating electrical failures and accidents in a legal context. Many forensic electrical engineering investigations apply to fires suspected to be caused by electrical failures. Forensic electrical engineers are most commonly retained by insurance companies or attorneys representing insurance companies, or by manufacturers or contractors defending themselves against subrogation by insurance companies. Other areas of investigation include accident investigation involving electrocution, and intellectual property disputes such as patent actions. Additionally, since electrical fires are most often cited as the cause for "suspect" fires an electrical engineer is often employed to evaluate the electrical equipment and systems to determine whether the cause of the fire was electrical in nature.
Goals
The ultimate goal of these investigations is often to determine the legal liability for a fire or other accident for purposes of insurance subrogation or an injury lawsuit. Some examples include:
Defective appliances: If a property fire was caused by an appliance which had a manufacturing or design defect (for example, a coffee maker overheating and igniting), making it unreasonably hazardous, the insurance company might attempt to collect the cost of the fire damage ("subrogate") from the manufacturer; if the fire caused personal injury or death, the injured party might also attempt an injury lawsuit against the manufacturer, in addition to the carrier of health or life insurance attempting subrogation.
Improper workmanship: If, for example, an electrician made an improper installation in a house, leading to an electrical fault and fire, he or she could likewise be the target of subrogation or an injury lawsuit (for this reason, electricians are required to carry liability insurance).
Electrical injury: If an electrical fault or unreasonably hazardous electrical system causes an electrical injury ("electrocution" if the injury is fatal), the party responsible for the electrical accident can be the target of insurance subrogation or an injury lawsuit.
Equipment failure: if electrical equipment stops functioning, it can cause a loss of income (such as a factory losing productivity due to inoperative equipment) or additional damage (such as food products spoiling due to loss of refrigeration), and again be the subject of a subrogation or liability case. Liability in such a case can also include the cost of repairing or replacing the equipment, which can be substantial.
Applications
Forensic electrical engineers are also involved in some arson and set-fire investigations; while it is not common for arsonists to cause electrical failures to ignite fires, the presence of electrical appliances and systems in many fires scenes often requires them to be evaluated as possible accidental causes of the fire. Some electrical means of ignition, when discovered, are fairly obvious to an origin and cause investigator and most likely do not require consulting with a forensic electrical engineer. (Note that "arson" refers specifically to a criminal act, subject to criminal prosecution; a more general term is a "set fire". A homeowner setting a fire deliberately in order to defraud an insurance company might be prosecuted for arson by a government body; however, the insurance company would concern itself only with denying the insurance claim, possibly leading to a civil lawsuit.)
Patent disputes may also require the expert opinion of an electrical engineer to advise a court. Issues in conflict may include the precise meaning of technical terms, especially in the patent claims, the prior art in a particular product field and the obviousness of various patents.
Liability
Most states have a statute of ultimate repose (similar to, but not to be confused with, a statute of limitations) that limits the length of time after which a party can legally be held liable for their negligent act or defective product. Many states have a "useful life" statute of ultimate repose. Therefore, a determination of the length of time the product would normally be expected to be used before wearing out needs to be made. For example, a refrigerator might have a longer "useful life" than an electric fan; an airplane might have a longer useful life than a car. Some states pick an arbitrary number of years for the statute of ultimate repose. It may be short (six or seven years) or longer 15 or 25 years. If a coffee maker starts on fire after the statute of ultimate repose has expired, the manufacturer can no longer be held liable for manufacturing or design defects. The statute of ultimate repose is different from the statute of limitations. In a state with a short statute of ultimate repose, it is common that a person's right to bring a claim in court expires before their injury ever occurs. Thus, if a defective product (for example a car) caused a collision when the steering failed, but the collision occurred after the expiration of a statute of ultimate repose, no claim could be brought against the manufacturer for selling a defective product. The right to bring the claim expired before the claim even occurred.
See also
NFPA 70 (the National Electrical Code)
NFPA 921 ("Guide for Fire and Explosion Investigations")
Kirk's Fire Investigation (textbook by John DeHaan)
Arc mapping
Origin and cause investigation
Fire investigation
References
Engineering disciplines
Electrical engineering | Forensic electrical engineering | Engineering | 1,045 |
35,557,898 | https://en.wikipedia.org/wiki/Biology%20and%20consumer%20behaviour | Consumer behaviour is the study of the motivations surrounding a purchase of a product or service. It has been linked to the field of psychology, sociology and economics in attempts to analyse when, why, where and how people purchase in the way that they do. However, little literature has considered the link between consumption behaviour and the basics of human biology. Segmentation by biological-driven demographics such as sex and age are already popular and pervasive in marketing. As more knowledge and research is known, targeting based on consumers' biology is of growing interest and use to marketers.
As "human machines" being made up of cells controlled by a brain to influence aspects of behaviour, there must be some influence of biology on consumer behaviour and how purchase decisions are made as well. The nature versus nurture debate is at the core of how much biology influences these buying decisions, because it argues how much is can be explained through environmental and by biological factors. Neuromarketing is of interest to marketers in measuring the reaction of stimulus to marketing.
Lawson and Wooliscroft (2004) drew the link between human nature and the marketing concept, not explicitly biology, where they considered the contrasting views of Hobbes and Rousseau on mankind. Hobbes believed man had a self-serving nature whereas Rousseau was more forgiving towards the nature of man, suggesting them to be noble and dignified. Hobbes saw the need for a governing intermediary to control this selfish nature which provided a basis for the exchange theory, and also links to Mcgregor's Theory of X and Y, relevant to management literature. He also considered cooperation and competition, relevant to game theory as an explanation of man's motives and can be used for understanding the exercising of power in marketing channels. Pinker outlines why the nature debate has been suppressed by the nurture debate in his book The Blank Slate.
Nature and consumer behaviour
Genes
Cells are the building blocks of all living organisms. Within these cells are coils of DNA, genetic information instructing for how cells will develop and operate. A small segment of DNA is a gene which codes for the making of proteins and passing on traits to offspring in reproduction. The main goal of a gene is to reproduce and thrive in its environment in relative to competitors. Practical implications in crime investigation, disorders and increasingly talent prediction and career decision making have considered their association with genes and biology, but the idea of biology and marketing is a growing body of knowledge. Neuromarketing is a new phenomenon studying consumer's reactions to marketing stimuli.
Biology affecting behaviour
Gene-centric view
Richard Dawkins outlines in The Selfish Gene (1976) that humans are machines made of genes, and genes are the grounding for everything people do. The gene-centric view outlines that natural selection, evolution and all behaviour must be traced back to the survival of competing genes as an extension of Darwin's theory being the survival of competing individuals. The main goal of individuals, coming from genes, is to reproduce and thrive, where thriving involves protection, conquering competition and future growth. Therefore, everything that people do relates to thriving in their environment above competition, including the way people consume as a form of survival in their environment when simply purchasing the basic physiological needs of food, water and warmth. People also consume to thrive above others, for example in conspicuous consumption where a luxury car represents money and high social status and the application of makeup makes the person and their genes seem more attractive and worthy of passing to offspring.
At least some behaviour must be influenced by genes because behaviour depends on the interaction of molecules and neurons in the brain. These interactions are a result of genes, however the influence on behaviour cannot go much further than this. Dawkins likened genes to a computer. They have been pre-programmed to build cells, develop cells and make them work together. Like a computer, the hardware is set in stone, but the software can change how they work, just like their environment. Genes indirectly influence behaviour as the nervous system and the brain is the intermediary in the transaction decision because it reasons and processes all of the gene instructions into one decision, movement or behaviour. The way neurons connect is dependent on the environment, learning and experience. This introduces the nurture side of the nature nurture debate.
Behaviour affecting biology
Epigenetics
Epigenetics is referred to as the ‘new genetics’ and phenomenon of importance to marketers because it studies how the environment can influence genes, and hence behaviour. The theory of meiosis is that exact replicas of parents' genes are passed to their offspring, with no variation influence from the environment. However genes have a protein wrapping the gene that can influence the gene expression and therefore phenotypes to the environment. How people act and consume now affects their epigenome, and consequently their offspring's genome. This supports Lamark's theory, prior to Darwin, who initially proposed the theory of genes changing with behaviour and experience. A study from the University of Auckland warned pregnant women against dieting due to the increased likelihood in their child acquiring eating disorders such as obesity, hence the way people consume food.
Nurture and consumer behaviour
The other side of the debate is the environment can shape attitudes, learning, sensation, thinking and behaviour
Attitudes
People who differ in attitudes toward education probably have different beliefs about the benefit of tertiary education, different feelings about having to go to class and different levels of commitment with respect to effort in assignments.
Attitude formation can be based on facts where a rational approach is taken, weighing up the pros and cons. A lot of the time, however, people acquire their attitudes from their parents, friends, and surrounding culture through a variety of learning mechanisms. is a somewhat disturbing example of this. Marketers have long been aware of the influence of peers on attitudes and this is a particularly important concept for subcultures which are socially oriented and experienced based. Participants communicate via many means and move between geographic locations. An example of a subculture is straight edge and their consumption is therefore affected by the socially constructed attitudes of the subgroup.
The elaboration likelihood model determines how easily attitudes can be changed. If the message goes through the peripheral route, people are far more likely to be influenced by how or whom or what surroundings the message is presented in. Therefore, advertising using a celebrity endorser such as Justin Bieber for Proactive may have a large impact on a person's attitude to skin care if the message is going through the latter route.
Learning
Habituation is shared across species and is the simplest form of learning. Here a person's response to a stimulus weakens when it becomes familiar. For example, with drink driving advertising in New Zealand, a decade ago people saw cars smashing into each other as a scare tactic. The content of these adverts has become less and less shocking the more people have been exposed to them. People have now become so desensitised to them that a humour approach has to be taken and the latest example is the ‘Legend’ advert.
Classical conditioning is demonstrated in a real-world office setting.
B. F. Skinner, theorist of operant conditioning, shows how a pigeon has been taught to distinguish between two words and behaves appropriately depending on which one is being presented. It learned each response with a reward of food therefore its behaviour is being shaped by controlling its environment. An example of this conditioning in a consumer behaviour context is a cinema using a consumer incentive scheme. A consumer given a card which entitles the person to a free movie if the person brings a friend and free popcorn on Tuesdays with the purchase of a ticket per se, they are more likely to go to a movie when perhaps they wouldn't have otherwise.
Shaping is a learning technique and one of the most useful concepts for marketers assisting in the initial purchase of any new product.
Sensation
Empiricists argue all knowledge comes from the senses, but if senses are only relevant to the proximal world, how do people know the distal world? They argue it is through learning and that prior experience plays a crucial role in shaping the perceptual world. Association is a key function which here refers to linking one sensory experience to another.
Thinking
Association is also relevant in enhancing generic memory. Many New Zealanders associate Phil Collins's song ‘In the air tonight’ and a gorilla playing on a drum set with a Cadbury Chocolate advertisement.
Language
Under normal conditions, language seems to develop in a similar way among all children but when children grow up in a radically different environment their language is significantly different. A number of examples including wild children show that certain elements of the early environment are essential for language learning. Amala and Kamala and Genie never managed to fully progress to learning language. While these examples are extreme, they show that consumer's language is affected by their environment. This is especially true of marketing activities across geographical borders.
Behaviour
The environment has a profound effect on development. Social deprivation in infants and children leads to dramatic behavioural deficits as evident in the behaviour of Romanian orphans. In a consumer behaviour context, vicarious learning which involves changing behaviour by having an individual observe the actions of another and witness the consequences of that behaviour, is used to develop new responses and inhibit undesired behaviours. The former is done through educating consumers in product uses i.e. through product demonstrations and increasing attention to the message i.e. through celebrity endorsement.
Nature versus Nurture
Matt Ridley suggests in Nature via Nurture (2003) the diversity of the human species is not hard-wired in the genetic code, environments are critical. Nature is not at the expense of nurture, nor is nurture at the expense of nature, there is room for both; they work together.
Genes are cogs in the machine, not gods in the sky. They are switched on and off throughout life, by external as well as internal events, their job is to absorb information from the environment at least as often as to transmit it from the past. Genes do more than carry information; they respond to experience. Susan Mineka illustrated this concept exceedingly well with her idea of prepared learning in monkeys, where she found the predisposition of genes largely affected the acquisition of fear responses to certain stimuli. Lab-reared monkeys, through vicarious experience, were easily able to acquire a fear response to a snake, but not a flower. Nature provides the instinct, and elements of nurture depend on whether the instinct is expressed.
Genes predispose individuals to determine the extent to which an individual may engage or interact with certain environments. Ridley exemplified that having ‘athletic’ genes makes one want to practice a sport, and having ‘intellectual’ genes makes one seek out intellectual activities. "The genes are the agents of nurture and are more likely to be affecting appetite more than aptitude". Genes do not make the individual intelligent, the make them more likely to enjoy learning. They encourage individuals to seek out environmental influences that will satisfy their appetites. "The environment acts as a multiplier of small genetic differences, pushing athletic children toward the sports that reward them, and pushing bright children to the books that reward them".
Whether an individual develops certain diseases or disorders is also established, to a certain degree, on the basis of nature and nurture. Genes often predispose individuals to certain disorders or diseases, while environmental factors can trigger the onset. Susceptibility of diabetes is determined by inherited differences in DNA, but environmental factors such as diet, weight, age, and physical activity seem to be triggering the onset of the disease. Genetic make-up, in addition to the environment with which the genes are exposed to, is influencing the behaviour of consumers with regard to the food choices they make. Addiction to substance abuse is partially determined by genes, which predispose individuals to have addictive personalities; however the stimuli with which an addiction develops is dependent on the environment. Addiction is persistent and compulsive, and has a significant impact upon consumer behaviour. Individuals who experience substance abuse, for example, are prone to basing their consumption primarily around the purchasing of alcohol, even at the expense of other important aspects of well-being.
Biological segmentation
The link between biology and marketing is not a new phenomenon, especially through segmentation based on the biology of sex, age, and health condition. Certain products, for example, maternity products, are targeted at certain consumers based on their biology. Maternity clothes are purposely advertised to pregnant females looking to consume based on their changing biological processes and female predisposition. The extent to which consumers are segmented and feel they are included or excluded in the segmentation in an ethical way makes this biological segmentation of growing interest for academics and marketers today. Various industries such as the insurance industry have been criticized to discriminate against consumers based on biology due to the use of genetic tests, where those with genetic diseases may have a higher premium. As scientists and marketers learn more about biology and gain greater access to consumer's biological information, ethical debates become increasingly apparent when engaging in marketing practices.
Neuromarketing
Measuring consumers' conscious and subconscious through studying their biological sensorimotor, cognitive and affective response to marketing stimuli, called neuromarketing, is of increasing interest to marketers in order to gain insight into how they consume. Dawkins (1989) explained that when people die they leave behind genes and memes; genes being the unit of genetic information, and memes the units of cultural information. Neuromarketing aims to examine the memory of these memes in order to manipulate them.
Through fMRI, EEG, steady state topography (SST) and magnetoencephalography (MEG) scans, marketers are able to study how consumers react, as a step towards understanding how they can influence consumption through marketing efforts. In conjunction with qualitative research methods, it can provide deep understanding into what, how and why people consume. Measuring eye tracking in e-service marketing is another example of quantitative biological methods measuring the way people consume. It analyses how consumers shop in an online environment by recording the number of mouse clicks and click maps based on eye movement.
The famous Coke vs Pepsi study used fMRI scans to show consumers sensory taste preference to Pepsi to Coca-Cola. However, when participants were told they were drinking Coke, their brain activity also changed and they stated their preference for Coca-Cola. This shows that regardless of their biology and sensory reaction, people's consumption behaviour and preferences are influenced by the environment, in this case the perception of brands.
References
Behavioral economics
Behavioural genetics | Biology and consumer behaviour | Biology | 2,960 |
10,353,141 | https://en.wikipedia.org/wiki/West%20Virginia%20statistical%20areas | The U.S. currently has 20 statistical areas that have been delineated by the Office of Management and Budget (OMB). On July 21, 2023, the OMB delineated five combined statistical areas, 10 metropolitan statistical areas, and five micropolitan statistical areas in . As of 2023, the largest of these is the Charleston-Huntington-Ashland, WV-OH-KY CSA, which includes West Virginia's capital and largest city, Charleston.
Table
Primary statistical areas
Primary statistical areas (PSAs) include all combined statistical areas and any core-based statistical area that is not a constituent of a combined statistical area. Of the 20 statistical areas of West Virginia, 11 are PSAs comprising five combined statistical areas, three metropolitan statistical areas and three micropolitan statistical areas.
See also
Geography of West Virginia
Demographics of West Virginia
Notes
References
External links
Office of Management and Budget
United States Census Bureau
United States statistical areas
Statistical Areas Of West Virginia
Statistical Areas Of West Virginia | West Virginia statistical areas | Mathematics | 202 |
41,045,246 | https://en.wikipedia.org/wiki/Sound%20map | Sound maps are digital geographical maps that put emphasis on the sonic representation of a specific location. Sound maps are created by associating landmarks (streets in a city, train stations, stores, pathways, factories, oil pumps, etc.) and soundscapes.
The term “soundscape” refers to the sonic environment of a specific locale. It may also refer to actual environments, or to abstract constructions such as musical compositions and tape montages, particularly when considered as an artificial environment. The objective of sound maps is to represent a specific environment using its soundscape as primary references as opposed to visual cues. Sound maps are in many ways the most effective auditory archive of an environment. Sound maps are similar to sound walks which are a form of active participation in the soundscape. Soundwalks and indeed, sound maps encourage the participants to listen discriminatively, and moreover, to make critical judgments about the sounds heard and their contribution to the balance or imbalance of the sonic environment. However, soundwalks will plot out a route for the user to follow and give guidance as to what the user may be hearing at each checkpoint. Sound maps, on the other hand, have specific soundscapes recorded that users can listen to at each checkpoint.
History / Background
The theoretical framework upon which sound maps are based derive from earlier research on acoustic ecology and soundscapes, the later being a term first coined by researcher and music composer R. Murray Schafer in the 1960s. Looking to challenge traditional ideas of recording reality, Schafer, along with several college music composers such as Barry Truax and Hildegard Westerkamp, funded the World Soundscape Project, an ambitious sound recording project that led the team based in Simon Fraser University to travel within Canada and out in Europe to collect data on local soundscapes. The sounds that they recorded were used to build a database of locales not based on the visual, but on their acoustic particularities. The result of the project had been released to the public in the form of a series of books entitled The Music of the Environment series which included narrative accounts of the soundscape recording activity (European Sound Diary) and soundscape analysis (Five Village Soundscapes). However, when those works were first published, the recordings were not available for the public to listen to as the project mainly aimed at building a database of sound over a long period of time. The World Soundscape Project also birthed a major theoretical framework for future studies of acoustic ecology and soundscapes, among them R. Murray Schafer’s The Tuning of the World in which the idea of soundscape studies was first introduced as well as Barry Truax’s The World Soundscape Project's Handbook for Acoustic Ecology that presented the foundational terminology for research in the field.
Sound maps make use of new computer locative technologies to achieve the similar purpose of preserving the soundscape of specific locales, but differs in the way of presenting the sound database. Through digital technologies such as mapping software and audio file encoding, the objective of using sound maps is partly that of making a soundscape database available to the public in a comprehensive fashion by uploading each site-specific soundscape onto a digital map as well as making the end product available for public collaboration. Users are able to pull up a map of the city and click on the sound clip icons in order to hear the soundscape for that location. Some sound maps are crowd-sourced and therefore allow the public to record their own soundscapes and upload them onto the digital map provided by the site hosting the sound map. Therefore, the soundscape database is built by the public and made available to the public for use.
Applications
The Sound Around You Project
The Sound Around You Project began as a soundscape research project at the University of Salford, UK in 2007. The project allows people to use audio recorders to record clips or sonic postcards of around 30 seconds in length from different sound environments, or ‘soundscapes’ from a family car journey to a busy shopping centre, and to upload them to the virtual map, along with their opinions of them and why they chose to record it. Sound Around You aims to raise awareness of how soundscape influences people.
New York Sound Map
New York Sound Map (NYSoundmp) is a project of The New York Society for Acoustic Ecology (NYSAE), a New York metropolitan chapter of the American Society for Acoustic Ecology, an organization dedicated to exploring the role of sound in natural habitats and human societies, and promoting public dialog concerning the identification, preservation, and restoration of natural and cultural sound environments. The NYSAE's purpose is to explore and create an ongoing dialog regarding aural experience specific to New York City. The NYSoundmap project is the direct result of the NYSAE's interest in collecting and disseminating the city's aural experiences to the general public. Through the NYSoundmap project, the NYSAE aims to facilitate a dialogue between people from a wide variety of communities and backgrounds - from beginners to professional sound artists and musicians.
Stanley Park Soundmap
The Stanley Park Soundmap is a web-based document of the sonic attributes of one of North America's largest urban parks located in Vancouver, British Columbia, Canada. Using a GPS unit, and a compact digital audio recorder 13 positions in the park were documented on Thursday, March 12, 2009. The location data and sound recordings were then linked to a map created in a Geographic Information Systems (GIS) based desktop application.
Montréal Sound Map
Montréal Sound Map is a web-based soundscape project that allows users to upload field recordings to a Google Map of Montréal. The soundscape is fluid, and the project is meant to act as "a sonic time capsule with the goal of preserving sounds before they disappear".
Sonoteca Bahia Blanca
Sonoteca Bahia Blanca is a virtual platform that aims to provide a common space for the collection, concentration, sharing and distribution of sound through its georeferencing and organization in a database, from a collaborative, supportive cultural practice and community status. The project seeks to enhance the sound heritage of the city.
Cities and Memory
Cities and Memory is a collaborative sound art and field recording project which centres around a global sound map covering more than 120 countries and territories with every location featuring a field recording but also a reimagined composition based on that recording. The map features more than 6,000 sounds and 1,600 contributing artists.
See also
Soundscape
Ambient music
Biomusic
Biophony
Field recording
Noise map
Sound art
Sound sculpture
Space music
Soundwalk
R. Murray Schafer
Further reading
Schafer, Raymond Murray (ed.) (1977). European Sound Diary. Vancouver : A.R.C. Publications : A.R.C. the Aesthetic Research Centre ; Burnaby, B.C. : World Soundscape Project.
Schafer, Raymond Murray (ed.) (2009). Five Villages Soundscape (2nd edition) Joensuu: Tampereen Ammattikorkeakoulu University of Applied Sciences (1st edition 1977).
Smith, J. Susan (1994). "Soundscape". Area, Vol. 26, No.3, pp. 232–240. The Royal Geography Society.
Waldock, Jacqueline (2011)."SOUNDMAPPING: Critiques And Reflections On This New Publicly Engaging Medium". Journal of Sonic Studies, volume 1, nr. 1.
2006 The West Meets the East in Acoustic Ecology (Tadahiko Imada, Kozo Hiramatsu et al. Eds), Japanese Association for Sound Ecology & Hirosaki University International Music Centre
Sound file
Wind Portlandreginal(2011) by Scott Smallwood
Artcar(2011) by Scott Smallwood
References
External links
Sound Mapping 1998
New York Sound Map
Sound Map of Budapest
Sound Map of Bratislava
Cerrado Ambisônico
Sound Map of Krakow
Sound Map of Wroclaw
Belgrade Sound map
Rabeca.org
Basque country sound map
Santorini Sound map
Stanley Park Sound map
Sonoteca Bahia Blanca Sound Map
Montréal Sound map
the MoMa Studio
radio aporee ::: maps global soundmap project
Experimental music
Sound
Acoustics | Sound map | Physics | 1,680 |
383,833 | https://en.wikipedia.org/wiki/Implosion%20%28mechanical%20process%29 | Implosion is the collapse of an object into itself from a pressure differential or gravitational force. The opposite of explosion (which expands the volume), implosion reduces the volume occupied and concentrates matter and energy. Implosion involves a difference between internal (lower) and external (higher) pressure, or inward and outward forces, that is so large that the structure collapses inward into itself, or into the space it occupied if it is not a completely solid object. Examples of implosion include a submarine being crushed by hydrostatic pressure and the collapse of a star under its own gravitational pressure.
In some but not all cases, an implosion propels material outward, for example due to the force of inward falling material rebounding, or peripheral material being ejected as the inner parts collapse. If the object was previously solid, then implosion usually requires it to take on a more dense form—in effect to be more concentrated, compressed, or converted into a denser material.
Examples
Nuclear weapons
In an implosion-type nuclear weapon design, a sphere of plutonium, uranium, or other fissile material is imploded by a spherical arrangement of explosive charges. This decreases the material's volume and thus increases its density by a factor of two to three, causing it to reach critical mass and create a nuclear explosion.
In some forms of thermonuclear weapons, the energy from this explosion is then used to implode a capsule of fusion fuel before igniting it, causing a fusion reaction (see Teller–Ulam design). In general, the use of radiation to implode something, as in a hydrogen bomb or in laser driven inertial confinement fusion, is known as radiation implosion.
Fluid dynamics
Cavitation (bubble formation/collapse in a fluid) involves an implosion process. When a cavitation bubble forms in a liquid (for example, by a high-speed water propeller), this bubble is typically rapidly collapsed—imploded—by the surrounding liquid.
Astrophysics
Implosion is a key part of the gravitational collapse of large stars, which can lead to the creation of supernovas, neutron stars and black holes.
In the most common case, the innermost part of a large star (called the core) stops burning and without this source of heat, the forces holding electrons and protons apart are no longer strong enough to do so. The core collapses in on itself exceedingly quickly, and becomes a neutron star or black hole; the outer layers of the original star fall inwards and may rebound off the newly created neutron star (if one was created), creating a supernova.
Cathode-ray tube and fluorescent lighting implosion
A high vacuum exists within all cathode-ray tubes. If the outer glass envelope is damaged, a dangerous implosion may occur. The implosion may scatter glass pieces at dangerous speeds. While modern CRTs used in televisions and computer displays have epoxy-bonded face-plates or other measures to prevent shattering of the envelope, CRTs removed from equipment must be handled carefully to avoid injury.
Controlled structure demolition
The demolition of large buildings using precisely placed and timed explosions so that the structure collapses on itself is often erroneously described as implosion.
See also
Type II supernova
References
External links
Converging Shock Waves
Mechanics
Implosion | Implosion (mechanical process) | Physics,Engineering | 691 |
43,141,101 | https://en.wikipedia.org/wiki/European%20Glass%20Experience | European Glass Experience is a project coordinated by the City of Venice in collaboration with Consorzio Promovetro Murano and the Murano Glass Museum. It represents an international celebration of contemporary glass art and, most of all, of its makers.
The project
EGE was officially launched on September 11, 2013 during a press conference at Ca' Farsetti in Venice, and its aim is to valorise the glass art on a European level, and to promote the works of local and international young artists. European Glass Experience was established to reinforce glass production and to improve the artistic heritage of traditional glass working experience. The project has among its partners The Finnish Glass Museum, Riihimäki, Finland, and the Fundación Centro Nacional del Vidrio, La Granja de San Idelfonso, Segovia, Spain. Associated partners are the Glass Factory in Boda Glasbruk, Sweden, the Muzeum Witrazu (Stained Glass Museum) in Kraków, the International Festival of Glass in Stourbridge, England and the Glass Museum of Marinha Grande (Portugal). European Glass Experience project is co-financed by a prestigious two-year grant from the Culture Program 2007–2013 of the European Union. The project will last two years, and it is composed by an exhibition which will take place in three different museums, divided into two sections: 40 unreleased glass artworks and 20 sketches which will become artworks, realised by Promovetro's Murano glass masters.
The exhibition
The exhibition began at The Finnish Glass Museum, Riihimaki, Finland, in March 2014, curated by Uta Laurén, and then continued to the Fundación Centro Nacional del Vidrio, Spain, under the directorship of Paloma Pastor. The final venue will be the Murano Glass Museum, directed by Chiara Squarcina in March 2015. Further additional venues, among the associated partners, will possibly follow. European Glass Experience team panel, made of museum directors, curators, and glass experts, selected nearly 80 sketches and artworks, coming from young artists of different cultures. Murano Glass masters associated with Promovetro are going to realize a selection of the most peculiar sketches in glass.
See also
Caneworking
Creative Europe
Glassblowing
External links
Partners
Civic Museums Foundation of Venice
The Finnish Glass Museum
Segovia National Center of Glass Foundation
Promovetro Consortium, Association of a group of Murano Glassmakers
Associated Partners
International Festival of Glass
The Glass Factory
Muzeum Witrażu
References
Venetian glass
History of glass
Glass trademarks and brands
Glass museums and galleries | European Glass Experience | Materials_science,Engineering | 520 |
2,841,008 | https://en.wikipedia.org/wiki/Holomorph%20%28mathematics%29 | In mathematics, especially in the area of algebra known as group theory, the holomorph of a group , denoted , is a group that simultaneously contains (copies of) and its automorphism group . It provides interesting examples of groups, and allows one to treat group elements and group automorphisms in a uniform context. The holomorph can be described as a semidirect product or as a permutation group.
Hol(G) as a semidirect product
If is the automorphism group of then
where the multiplication is given by
Typically, a semidirect product is given in the form where and are groups and is a homomorphism and where the multiplication of elements in the semidirect product is given as
which is well defined, since and therefore .
For the holomorph, and is the identity map, as such we suppress writing explicitly in the multiplication given in equation () above.
For example,
the cyclic group of order 3
where
with the multiplication given by:
where the exponents of are taken mod 3 and those of mod 2.
Observe, for example
and this group is not abelian, as , so that is a non-abelian group of order 6, which, by basic group theory, must be isomorphic to the symmetric group .
Hol(G) as a permutation group
A group G acts naturally on itself by left and right multiplication, each giving rise to a homomorphism from G into the symmetric group on the underlying set of G. One homomorphism is defined as λ: G → Sym(G), λg(h) = g·h. That is, g is mapped to the permutation obtained by left-multiplying each element of G by g. Similarly, a second homomorphism ρ: G → Sym(G) is defined by ρg(h) = h·g−1, where the inverse ensures that ρgh(k) = ρg(ρh(k)). These homomorphisms are called the left and right regular representations of G. Each homomorphism is injective, a fact referred to as Cayley's theorem.
For example, if G = C3 = {1, x, x2 } is a cyclic group of order three, then
λx(1) = x·1 = x,
λx(x) = x·x = x2, and
λx(x2) = x·x2 = 1,
so λ(x) takes (1, x, x2) to (x, x2, 1).
The image of λ is a subgroup of Sym(G) isomorphic to G, and its normalizer in Sym(G) is defined to be the holomorph N of G.
For each n in N and g in G, there is an h in G such that n·λg = λh·n. If an element n of the holomorph fixes the identity of G, then for 1 in G, (n·λg)(1) = (λh·n)(1), but the left hand side is n(g), and the right side is h. In other words, if n in N fixes the identity of G, then for every g in G, n·λg = λn(g)·n. If g, h are elements of G, and n is an element of N fixing the identity of G, then applying this equality twice to n·λg·λh and once to the (equivalent) expression n·λgg gives that n(g)·n(h) = n(g·h). That is, every element of N that fixes the identity of G is in fact an automorphism of G. Such an n normalizes λG, and the only λg that fixes the identity is λ(1). Setting A to be the stabilizer of the identity, the subgroup generated by A and λG is semidirect product with normal subgroup λG and complement A. Since λG is transitive, the subgroup generated by λG and the point stabilizer A is all of N, which shows the holomorph as a permutation group is isomorphic to the holomorph as semidirect product.
It is useful, but not directly relevant, that the centralizer of λG in Sym(G) is ρG, their intersection is , where Z(G) is the center of G, and that A is a common complement to both of these normal subgroups of N.
Properties
ρ(G) ∩ Aut(G) = 1
Aut(G) normalizes ρ(G) so that canonically ρ(G)Aut(G) ≅ G ⋊ Aut(G)
since λ(g)ρ(g)(h) = ghg−1 ( is the group of inner automorphisms of G.)
K ≤ G is a characteristic subgroup if and only if λ(K) ⊴ Hol(G)
References
Group theory
Group automorphisms | Holomorph (mathematics) | Mathematics | 1,062 |
25,199,553 | https://en.wikipedia.org/wiki/Operand%20forwarding | Operand forwarding (or data forwarding) is an optimization in pipelined CPUs to limit performance deficits which occur due to pipeline stalls. A data hazard can lead to a pipeline stall when the current operation has to wait for the results of an earlier operation which has not yet finished.
Example
ADD A B C #A=B+C
SUB D C A #D=C-A
If these two assembly pseudocode instructions run in a pipeline, after fetching and decoding the second instruction, the pipeline stalls, waiting until the result of the addition is written and read.
In some cases all stalls from such read-after-write data hazards can be completely eliminated by operand forwarding:
Technical realization
The CPU control unit must implement logic to detect dependencies where operand forwarding makes sense. A multiplexer can then be used to select the proper register or flip-flop to read the operand from.
See also
Feed forward (control)
References
External links
Introduction to Pipelining
Instruction processing | Operand forwarding | Technology,Engineering | 205 |
11,488,016 | https://en.wikipedia.org/wiki/Luminous%20red%20nova | A luminous red nova (abbr. LRN, pl. luminous red novae, pl.abbr. LRNe) is a stellar explosion thought to be caused by the merging of two stars. They are characterised by a distinct red colour, and a light curve that fades slowly with resurgent brightness in the infrared. Luminous red novae are not related to standard novae, which are explosions that occur on the surface of white dwarf stars.
Discovery
A small number of objects exhibiting the characteristics of luminous red novae have been observed over the last 30 years or so. The red star M31 RV in the Andromeda Galaxy flared brightly during 1988 and may have been a luminous red nova. In 1994, V4332 Sagittarii, a star in the Milky Way galaxy, flared similarly, and in 2002, V838 Monocerotis followed suit and was studied quite closely.
The first confirmed luminous red nova was the object M85 OT2006-1, in the galaxy Messier 85. It was first observed during the Lick Observatory Supernova Search, and subsequently investigated by a team of astronomers from both U.C. Berkeley and Caltech. They confirmed its difference from known explosions such as novae and thermal pulses, and announced luminous red novae as a new class of stellar explosion.
V1309 Scorpii is a luminous red nova that followed the merger of a contact binary in 2008. In January 2015, a luminous red nova was observed in the Andromeda Galaxy. On February 10, 2015, a luminous red nova, known as M101 OT2015-1 was discovered in the Pinwheel Galaxy (M101).
Characteristics
The luminosity of the explosion occurring in luminous red novae is between that of a supernova (which is brighter) and a nova (dimmer). The visible light lasts for weeks or months, and is distinctively red in colour, becoming dimmer and redder over time. As the visible light dims, the infrared light grows and also lasts for an extended period of time, usually dimming and brightening a number of times.
Infrared observations of M85 OT2006-1 have shown that temperature of this star is slightly less than 1000 K, a rather low temperature. It is not clear if this characteristic is shared by other luminous red novae.
Evolution
The team investigating M85 OT2006-1 believe it to have formed when two main sequence stars merged. (See the article on V838 Mon for further information on mergebursts and alternative possibilities.)
At the time the mergeburst occurs, the LRN appears to expand extremely rapidly, reaching thousands to tens of thousands of solar radii in only a few months. This would cause the object to cool, explaining the intriguing co-existence of a bright flash with a cool post-flash object.
Other viewpoints
Some astronomers believe it to be premature to declare a new class of stellar explosions based on such a limited number of observations.
For instance, they may be due to a type II-p supernova; alternatively, supernovae undergoing a high level of extinction will naturally be both red and of low luminosity.
Prediction
In 2017 KIC 9832227, a binary star system, was predicted to merge and produce a red nova by early 2022. In September 2018, a typo was discovered in data used for the initial prediction, and it was determined that the merger would likely not take place at the predicted time.
See also
Binary star
Cataclysmic variable star
Dwarf nova
Hypernova
Nova
Supernova
References
External links
Caltech Press Release "Caltech and Berkeley Astronomers Identify a New Class of Cosmic Explosions"
Smithsonian/NASA ADS Astronomy Abstract Service "Spitzer Observations of the New Luminous Red Nova M85 OT2006-1"
Cosmos Online "Stars merge in new cosmic explosion"
Stellar phenomena | Luminous red nova | Physics | 786 |
40,777,299 | https://en.wikipedia.org/wiki/Radioactive%20Isotope%20Beam%20Factory | The Radioactive Isotope Beam Factory is a multistage particle accelerator complex operated by Japan's Nishina Center for Accelerator-Based Science which is itself a part of the Institute of Physical and Chemical Research. Located in Saitama, the RIBF generates unstable nuclei of all elements up to uranium and studies their properties. According to physicist Robert Janssens, "[it] can produce the most intense beams of primary particles in the world."
RIBF took ten years to construct and its Superconducting Ring Cyclotron (SRC) can achieve energies of 2,600 MeV.
Work at the RIBF has contributed to the understanding of atomic magic numbers.
See also
Rare isotope Accelerator complex for ON-line experiment
References
External links
RIBF Main Page
Research institutes in Japan
Nuclear research institutes | Radioactive Isotope Beam Factory | Physics,Engineering | 163 |
3,989,260 | https://en.wikipedia.org/wiki/Course-of-values%20recursion | In computability theory, course-of-values recursion is a technique for defining number-theoretic functions by recursion. In a definition of a function f by course-of-values recursion, the value of f(n) is computed from the sequence .
The fact that such definitions can be converted into definitions using a simpler form of recursion is often used to prove that functions defined by course-of-values recursion are primitive recursive. Contrary to course-of-values recursion, in primitive recursion the computation of a value of a function requires only the previous value; for example, for a 1-ary primitive recursive function g the value of g(n+1) is computed only from g(n) and n.
Definition and examples
The factorial function n! is recursively defined by the rules
This recursion is a primitive recursion because it computes the next value (n+1)! of the function based on the value of n and the previous value n! of the function. On the other hand, the function Fib(n), which returns the nth Fibonacci number, is defined with the recursion equations
In order to compute Fib(n+2), the last two values of the Fib function are required. Finally, consider the function g defined with the recursion equations
To compute g(n+1) using these equations, all the previous values of g must be computed; no fixed finite number of previous values is sufficient in general for the computation of g. The functions Fib and g are examples of functions defined by course-of-values recursion.
In general, a function f is defined by course-of-values recursion if there is a fixed primitive recursive function h such that for all n,
where is a Gödel number encoding the indicated sequence.
In particular
provides the initial value of the recursion. The function h might test its first argument to provide explicit initial values, for instance for Fib one could use the function defined by
where s[i] denotes extraction of the element i from an encoded sequence s; this is easily seen to be a primitive recursive function (assuming an appropriate Gödel numbering is used).
Equivalence to primitive recursion
In order to convert a definition by course-of-values recursion into a primitive recursion, an auxiliary (helper) function is used. Suppose that one wants to have
.
To define using primitive recursion, first define the auxiliary course-of-values function that should satisfy
where the right hand side is taken to be a Gödel numbering for sequences.
Thus encodes the first values of . The function can be defined by primitive recursion because is obtained by appending to the new element :
,
where computes, whenever encodes a sequence of length , a new sequence of length such that and for all . This is a primitive recursive function, under the assumption of an appropriate Gödel numbering; h is assumed primitive recursive to begin with. Thus the recursion relation can be written as primitive recursion:
where g is itself primitive recursive, being the composition of two such functions:
Given , the original function can be defined by , which shows that it is also a primitive recursive function.
Application to primitive recursive functions
In the context of primitive recursive functions, it is convenient to have a means to represent finite sequences of natural numbers as single natural numbers. One such method, Gödel's encoding, represents a sequence of positive integers as
,
where pi represent the ith prime. It can be shown that, with this representation, the ordinary operations on sequences are all primitive recursive. These operations include
Determining the length of a sequence,
Extracting an element from a sequence given its index,
Concatenating two sequences.
Using this representation of sequences, it can be seen that if h(m) is primitive recursive then the function
.
is also primitive recursive.
When the sequence is allowed to include zeros, it is instead represented as
,
which makes it possible to distinguish the codes for the sequences and .
Limitations
Not every recursive definition can be transformed into a primitive recursive definition. One known example is Ackermann's function, which is of the form A(m,n) and is provably not primitive recursive.
Indeed, every new value A(m+1, n) depends on the sequence of previously defined values A(i, j), but the i-s and j-s for which values should be included in this sequence depend themselves on previously computed values of the function; namely (i, j) = (m, A(m+1, n)). Thus one cannot encode the previously computed sequence of values in a primitive recursive way in the manner suggested above (or at all, as it turns out this function is not primitive recursive).
References
Hinman, P.G., 2006, Fundamentals of Mathematical Logic, A K Peters.
Odifreddi, P.G., 1989, Classical Recursion Theory, North Holland; second edition, 1999.
Computability theory
Recursion | Course-of-values recursion | Mathematics | 1,096 |
66,423,508 | https://en.wikipedia.org/wiki/List%20of%20laboratory%20biosecurity%20incidents | This list of laboratory biosecurity incidents includes accidental laboratory-acquired infections and laboratory releases of lethal pathogens, containment failures in or during transport of lethal pathogens, and incidents of exposure of lethal pathogens to laboratory personnel, improper disposal of contaminated waste, and/or the escape of laboratory animals. The list is grouped by the year in which the accident or incident occurred and does not include every reported laboratory-acquired infection.
See also
Biological hazard
Biosafety level
Laboratory safety
List of anthrax outbreaks
Select agent
Cambridge Working Group
External links
A Review of Laboratory-Acquired Infections in the Asia-Pacific: Understanding Risk and the Need for Improved Biosafety for Veterinary and Zoonotic Diseases
Laboratory-Acquired Infection (LAI) Database
Survey of laboratory-acquired infections around the world in biosafety level 3 and 4 laboratories
Notes
References
Biosecurity
Biosecurity incidents
Occupational safety and health | List of laboratory biosecurity incidents | Environmental_science | 186 |
2,802,690 | https://en.wikipedia.org/wiki/National%20Research%20Universal%20reactor | The National Research Universal (NRU) reactor was a 135 MW nuclear research reactor built in the Chalk River Laboratories, Ontario, one of Canada’s national science facilities. It was a multipurpose science facility that served three main roles. It generated radionuclides used to treat or diagnose over 20 million people in 80 countries every year (and, to a lesser extent, other isotopes used for non-medical purposes). It was the neutron source for the NRC Canadian Neutron Beam Centre: a materials research centre that grew from the Nobel Prize-winning work of Bertram Brockhouse. It was the test bed for Atomic Energy of Canada Limited to develop fuels and materials for the CANDU reactor. At the time of its retirement on March 31, 2018, it was the world's oldest operating nuclear reactor.
History
The NRU reactor design was started in 1949. It is fundamentally a Canadian design, significantly advanced from NRX. It was built as the successor to the NRX reactor at the Atomic Energy Project of the National Research Council of Canada at Chalk River Laboratories. The NRX reactor was the world's most intense source of neutrons when it started operation in 1947. It was not known how long a research reactor could be expected to operate, so the management of Chalk River Laboratories began planning the NRU reactor to ensure continuity of the research programs.
NRU started self-sustained operation (or went "critical") on November 3, 1957, a decade after the NRX, and was ten times more powerful. It was initially designed as a 200 MW reactor, fueled with natural uranium. NRU was converted to 60 MW with highly-enriched uranium (HEU) fuel in 1964 and converted a third time in 1991 to 135 MW running on low-enriched uranium (LEU) fuel.
On Saturday, 24 May 1958 the NRU suffered a major accident. A damaged uranium fuel rod caught fire and was torn in two as it was being removed from the core. The fire was extinguished, but a sizeable quantity of radioactive combustion products had contaminated the interior of the reactor building and, to a lesser degree, an area of the surrounding laboratory site. The clean-up and repair took three months. NRU was operating again in August 1958. Care was taken to ensure no one was exposed to dangerous levels of radiation and staff involved in clean-up were monitored over the following decades. A corporal named Bjarnie Hannibal Paulson who was at the clean up developed unusual skin cancers and received a disability pension.
NRU's calandria, the vessel which contains its nuclear reactions, is made of aluminum, and was replaced in 1971 because of corrosion. The calandria has not been replaced since, although a second replacement is likely needed. An advantage of NRU's design is that it can be taken apart to allow for upgrade and repair.
In October 1986, the NRU reactor was recognized as a nuclear historic landmark by the American Nuclear Society. Since NRX was decommissioned in 1992, after 45 years of service, there has been no backup for NRU.
In 1994, Bertram Brockhouse was awarded the Nobel Prize in Physics, for his pioneering work carried out in the NRX and NRU reactors in the 1950s. He gave birth to a scientific technique which is now used around the world.
In 1996, AECL informed the Canadian Nuclear Safety Commission (then known as the Atomic Energy Control Board) that operation of the NRU reactor would not continue beyond December 31, 2005. It was expected that a replacement facility would be built inside that time. However, no replacement was built and in 2003, AECL advised the CNSC that they intended to continue operation of the NRU reactor beyond December 2005. The operating licence was initially extended to July 31, 2006, and a 63-month licence renewal was obtained in July 2006, allowing operation of the NRU until October 31, 2011.
In May 2007, the NRU set a new record for the production of medical isotopes.
In June 2007, a new neutron scattering instrument was opened in NRU. The D3 Neutron Reflectometer is designed for examining surfaces, thin films and interfaces. The technique of Neutron Reflectometry is capable of providing unique information on materials in the nanometre length scale.
2007 shutdown
On November 18, 2007, the NRU reactor was shut down for routine maintenance. This shutdown was voluntarily extended when AECL decided to install seismically qualified emergency power systems (EPS) to two of the reactor's cooling pumps (in addition to the AC and DC backup power systems already in place), as required as part of its August 2006 operating license extension by the Canadian Nuclear Safety Commission (CNSC). This resulted in a worldwide shortage of radioisotopes for medical treatments because AECL had not pre-arranged for an alternate supply. On December 11, 2007, the House of Commons of Canada, acting on what the government described as "independent expert" advice, passed emergency legislation authorizing the restarting of the NRU reactor with one of the two seismic connections complete (one pump being sufficient to cool the core), and authorizing the reactor's operation for 120 days without CNSC approval. The legislation, C-38, was passed by the Senate and received Royal Assent on December 12. Prime Minister Stephen Harper accused the "Liberal-appointed" CNSC for this shutdown which "jeopardized the health and safety of tens of thousands of Canadians". Others viewed the actions and priorities of the Prime Minister and government in terms of protecting the eventual sale of AECL to private investors. The government later announced plans to sell part of AECL in May 2009.
The NRU reactor was restarted on December 16, 2007.
On January 29, 2008, the former President of the CNSC, Linda Keen, testified before a Parliamentary Committee that the risk of fuel failure in the NRU reactor was "1 in 1000 years", and claimed this to be a thousand times greater risk than the "international standard". These claims were refuted by AECL.
On February 2, 2008, the second seismic connection was complete. This timing was well within the above 120-day window afforded by Bill C-38.
2009 Shutdown
In mid-May 2009 a heavy water leak at the base of the reactor vessel was detected, prompting a temporary shutdown of the reactor. The leak was estimated to be 5 kg (<5 litres) per hour, a result of corrosion. This was the second heavy water leak since late 2008. The reactor was defuelled and drained of all of its heavy water moderator. No administrative levels of radioactivity were exceeded, during the leak or defuelling, and all leaked water was contained and treated on site.
The reactor remained shut down until August 2010. The lengthy shutdown was necessary to defuel the reactor, ascertain the full extent of the corrosion to the vessel, and finally to effect the repairs — all with remote and restricted access from a minimum distance of 8 metres due to the residual radioactive fields in the reactor vessel. The 2009 shutdown occurred at a time when only one of the other four worldwide regular medical isotope sourcing reactors was producing, resulting in a worldwide shortage.
Decommissioning
On March 31, 2018, following government direction to shut down operations, NRU was permanently shut down ahead of decommissioning scheduled to start in 2028.
Production of isotopes
With the construction of the earlier NRX reactor, it was possible for the first time to commercially manufacture isotopes that were not commonly found in nature. In the core of an operating reactor there are billions of free neutrons. By inserting a piece of target material into the core, atoms in the target can capture some of those neutrons and become heavier isotopes. Manufacturing medical isotopes was a Canadian medical innovation in the early 1950s.
The NRU reactor continued the legacy of NRX and until it was decommissioned March 31, 2018 produced more medical isotopes than any facility in the world.
Cobalt-60 from NRU is used in radiation therapy machines that treat cancer in 15 million patients in 80 countries each year. The NRU produced about 75% of the global supply. The decay of Cobalt-60 results in the emission of high energy photons.
Technetium-99m from NRU used in the diagnosis of 5 million patients each year represented about 80 per cent of all nuclear medicine procedures. The NRU produced over half of the world's total supply. Technetium-99m emits less energy as it decays than most gamma emitters, roughly as much as the X-rays from an X-ray tube. This can act as an in situ source for a special camera that creates an image of the patient called a SPECT scan. NRU actually produced the more stable parent isotope, molybdenum-99, which is shipped to medical labs. There it decays into technetium-99m, which is separated and used for testing.
NRU produced xenon-133, iodine-131 and iodine-125, which are used in a variety of diagnostic and therapeutic applications.
Carbon-14 produced in NRU was sold to chemistry, bioscience and environmental labs where it is used as a tracer.
Iridium-192 from NRU is used in several industries to inspect welds or other metal components to ensure they are safe for use.
The core of the NRU reactor was about wide and high, which is unusually large for a research reactor. That large volume enabled the bulk production of isotopes. Other research reactors in the world produce isotopes for medical and industrial uses, for example the European High Flux Reactor at Petten in the Netherlands, Maria Reactor in Poland, and the OPAL reactor in Australia which began operation in April 2007.
NRU was originally scheduled to shut down in October 2016. With no stable isotope manufacturer ready to step in until 2018, the Canadian Government allowed the NRU to produce Isotopes until March 2018.
Neutron beam research
The NRU reactor is home to Canada's national facility for neutron scattering: the NRC Canadian Neutron Beam Centre. Neutron scattering is a technique where a beam of neutrons shines through a sample of material, and depending on how the neutrons scatter from the atoms inside, scientists can determine many details about the crystal structure and movements of the atoms within the sample.
An early pioneer of the technique was Bertram Brockhouse who built some of the early neutron spectrometers in the NRX and NRU reactors and was awarded the 1994 Nobel Prize in physics for the development of neutron spectroscopy.
The NRC Canadian Neutron Beam Centre continues that field of science today, operating as an open-access user facility allowing scientists from across Canada and around the world to use neutrons in their research programs.
It is common for a developed country to support a national facility for neutron scattering and one for X-ray scattering. The two types of facility provide complementary information about materials.
An unusual feature of the NRU reactor as Canada's national neutron source is its multipurpose design: able to manufacture isotopes, and support nuclear R&D at the same time as it supplies neutrons to the suite of neutron scattering instruments.
The NRU reactor is sometimes (incorrectly) characterized as simply a nuclear research facility. Neutron scattering however is not nuclear research, it is materials research. Neutrons are an ideal probe of materials including metals, alloys, biomaterials, ceramics, magnetic materials, minerals, polymers, composites, glasses, nano-materials and many others. The neutron scattering instruments at the NRC Canadian Neutron Beam Centre are used by universities and industries from across Canada every year because knowledge of materials is important for innovation in many sectors.
Nuclear power research and development
The NRU reactor has test facilities built into its core that can replicate conditions inside a large electricity-producing reactor. NRU itself does not generate steam (or electricity); its cooling water heats up to approximately 55 degrees Celsius. Inside the test facilities though, high temperatures and pressures can be produced. It is essential to test out different materials before they are used in the construction of a nuclear generating station.
The fundamental knowledge gained from NRU enabled the development of the CANDU reactor, and is the foundation for the Canadian nuclear industry.
See also
Nuclear fission
Neutron scattering
Nuclear power
Nuclear waste
Nuclear power in Canada
References
External links
The NRU Reactor
NRC Canadian Neutron Beam Centre
Nuclear Accidents (Georgia State University)
"The Canadian Nuclear FAQ" by Dr. Jeremy Whitlock (in particular see the section "NRU Safety" regarding the Nov-Dec 2007 shutdown of isotope production)
The Society for the Preservation of Canada's Nuclear Heritage, Inc.
Atomic Energy of Canada Limited
Nuclear medicine organizations
Neutron-related techniques
Nuclear accidents and incidents
Nuclear research reactors
Nuclear technology in Canada | National Research Universal reactor | Chemistry,Engineering | 2,610 |
31,366,708 | https://en.wikipedia.org/wiki/Golden%20Pipeline%20Heritage%20Trail | Golden Pipeline Heritage Trail (also known as the Golden Pipeline Drive Trail) was a project conducted by the National Trust of Western Australia along the Goldfields Water Supply Scheme pipeline at the time the pipeline was being celebrated for its 100 years of operation.
Project
The project included the creation of guide books, web sites and other materials about the trail.
The project was initiated in the late 1990s;
further material was developed between 2001 and 2003, and included the Kep Track as part of the project.
Trail and related sites
Some communities along the trail have suffered due to change in agricultural decline, however most communities sustain museums or interpretative signage that give information about the pipeline's history.
As the heritage trail and working pipeline are continuing, considerable effort was expended to maintain and sustain the pipeline trail and its related sites (former pumping stations for example) over time.
The heritage trail achieved status on the Australian national heritage list in 2011.
Trail sections
The Golden Pipeline Heritage Trail is segmented into seven sections:
Mundaring to Northam
Northam to Cunderdin
Cunderdin to Kellerberrin
Kellerberrin to Merredin
Merredin to Southern Cross
Southern Cross to Coolgardie
Coolgardie to Kalgoorlie
See also
Great Eastern Highway, the road that most of the Golden Pipeline Heritage Trail follows
Notes
References
External links
The Golden Pipeline Project
The WA National Trust Website
Historic Civil Engineering Landmarks
Goldfields Water Supply Scheme
Great Western Woodlands
National Trust of Western Australia
Heritage trails in Western Australia
de:Golden Pipeline | Golden Pipeline Heritage Trail | Engineering | 304 |
40,067,524 | https://en.wikipedia.org/wiki/Oil%20industry%20in%20Poland | The oil industry in Poland began at Bóbrka Field in 1853 , followed by the first refinery in 1854. Poland was the third most productive region in the world in 1900. It now has only a small, mostly state-owned component, with production from its Permian Basin in the west, small and very old fields in the Carpathians in the south, and offshore in the Baltic Sea. For natural gas the country is almost completely dependent on legacy pipelines from the former Soviet Union.
Shale gas and tight oil
Production of significant quantities of natural gas or petroleum from shale or tight (low permeability) reservoirs is in large part dependent on the social acceptance and technical and commercial viability of hydraulic fracturing. As of 2013 only 3% of the Poles opposed fracking. Leasing for unconventional shale plays in Poland began in 2007. But, as of 2013, the results of exploration efforts, as well as government regulation, have been disappointing, and estimates of the size of the total resource have been substantially reduced. Data indicates a substantial resource, but the permeability of the rocks, combined with the relative complexity of the faulting in some areas, have made success elusive. In 2013, the Energy Information Administration, a U.S. agency, estimated that 146 trillion cubic feet of shale gas and of tight oil could be economically recovered from the shales in Poland using present technology. However, an estimate published in March 2013 of recoverable shale gas reserves by the Polish Geological Institute was 24.8 trillion cubic feet. It remains to be seen whether the lack of reservoir permeability can be overcome.
Poland has been dependent on a Soviet era gas pipeline system which brings in only expensive Russian gas. Power generation has been based on Poland's extensive reserves of coal, principally lignite. Development of a domestic gas industry to replace Russian imports is highly desirable as would the use of gas to retire or convert coal fired generation plants. Drilling for shale resources began in June 2010. But, as of July 2013, none of the wells which have been completed have produced gas in commercial quantities. ConocoPhillips, which purchased the most prospective geological area from Lane Energy Poland, was able to produce gas and oil in sustainable volumes. But, their costs were too high to justify the project. ExxonMobil, which positioned itself in the Lublin Basin, a highly faulted area, could never get a sustainable test, despite spending huge sums on geological research. Chevron also stubbed its toe in the Lublin Basin area, after receiving some bad geological advice. Talisman Energy also failed, and Marathon Oil drilled where there was little/no prospective shale resource. All have pulled out, leaving the Polish Oil and Gas Company as the prime company in the shale gas and tight oil plays.
In the absence of regulation acceptable to the drillers who have the technology and resources to engage in extensive exploration, as of 2013, the extent of the tight oil and shale gas resource in Poland remains unknown, although it is believed by some informed observers that it has the potential to supply the needs of Poland for hundreds of year. However, using current technology, it is considered likely that it will be more of a national security mandate than a commercial venture any time soon.
Polish firms
In addition to exploration for tight oil and shale gas by international firms there is a small Polish oil and gas industry with some oil and gas production:
Polskie Górnictwo Naftowe i Gazownictwo (PGNiG, literally: Polish Petroleum and Gas Mining) is a Polish state-controlled oil and natural gas company, which deals with the exploration and production of natural gas and crude oil, natural gas import, storage and distribution and sales of natural gas and crude oil. PGNiG is one of the largest companies in Poland and is listed on the Warsaw Stock Exchange
Przedsiębiorstwo Poszukiwań i Eksploatacji Złóż Ropy i Gazu "Petrobaltic" S.A. (Exploration and Mining of Petroleum and Gas Deposits Joint stock company "Petrobaltic") was set up in November 1990. On 1 January 1999, the firm was transformed in limited liability company and the only shareholder become the State Treasury. The company is the only firm in Poland performing exploration and production of crude oil and gas in the Baltic Sea. B3 oil field is currently in production and has a 2006 production of 1.9 million bbl/year. The company has its head office in Gdańsk. Exploration and exploitation of oil and gas deposits are performed with three drilling platforms: Petrobaltic, Baltic Beta and Jacket-type platform called "PG-1".
Historical firms
Polmin (English: State Factory of Mineral Oils, Polish: Panstwowa Fabryka Olejow Mineralnych) was a Polish state-owned enterprise, which controlled excavation, transport and distribution of natural gas. Founded in 1909, it was nationalized in 1927, with main office in Lwów. Polmin operated a large oil refinery in Drohobych, which in late 1930s employed around 3000 people. The refinery purified oil extracted from rich fields of southern part of the Second Polish Republic (Gorlice, Borysław, Jasło, and Drohobych). Some Polish-language sources claim that Polmin refinery in Drohobycz was in late 1930s the biggest in Europe.
Oil and gas fields in Poland
Oil fields
The first oil well was drilled at Bóbrka Field in 1853; it was 7 years after drilling the first oil well in Baku settlement (Bibi-Heybat) in 1846 on Apsheron peninsula.
The B3 oil field is an oil and gas field in the Baltic Sea. The field is located 80 km off the Polish coastal town Rozewie. The crude oil is also referred to as Rozewie crude. The API gravity of the crude is 42-43 and sulfur content of 0.12 wt%. The jack up rig Baltic Beta located on the field takes care of processing, drilling and accommodation. The associated gas is sent through a pipeline to the heat and power generating plant in Władysławowo. Most of the oil produced from B3 is shipped by tanker to Gdańsk and fed to the Gdańsk refinery as a small part of the refinery feedstock.
The B8 oil field is a major oil field in the Polish sector of the Baltic Sea about 70 km north of Jastarnia. The field was discovered in 1983 and started producing oil in 2006. The field currently (2023) accounts for four per cent of Poland’s oil production.
The Barnówko-Mostno-Buszewo oil field is an oil field that was discovered in 1993. It began production in 1994. Its proven oil reserves are about and proven reserves of natural gas are around 350 billion cubic feet (9.9×109m³).
The Dębno oil field is an oil field that was discovered in 2004. It began production in 2005. Its proven oil reserves are about and proven reserves of natural gas are around 283 billion cubic feet (8×109m³).
The Lubiatów-Międzychód-Grotów oil field is an oil field that was discovered in 1993. It began production in 1994. Its proven oil reserves are about and proven reserves of natural gas are around 160 billion cubic feet (4.5×109m³).
Gas fields
The Daszawa gas field was discovered in 1950. It began production in 1950. The proven reserves of natural gas of the Daszawa gas field are around 72 billion cubic feet (2×109m³).
The Dzików gas field, discovered in 1962, began production in 1965. Proven reserves are about 70 billion cubic feet (2×109m³).
Jasionka
Jodłówka
Kościan
Przemyśl
Radlin
Terliczka
Wola Obszańska
Żołynia
Refining, distribution, and retailing
Grupa Lotos S.A. was a vertically integrated oil company based in Gdańsk. The company is listed in the Polish index WIG 20. Its main activity branches were: crude oil production, refining and marketing of oil products. The company was a leader in lubricants on the Polish market. Grupa Lotos was a producer of unleaded gasoline, diesel, fuel oils, aviation fuels, motor and industrial lubricants, bitumens and waxes. It merged with PKN Orlen in 2022.
PKN Orlen () () is a major Polish oil refiner, and petrol retailer. The company is the Central Europe's largest publicly traded firm with major operations in Poland, Czech Republic, Germany, Slovakia, and the Baltic States. In 2009, it was ranked in the Fortune Global 500 as the world's 31st largest oil company and the world's 249th largest company overall, and was the only Polish company ranked by Fortune. It currently (2012) ranks 297th, with a revenue of over US$36.1 billion.
The Płock refinery is an oil refinery and petrochemical complex in Płock owned by PKN Orlen. The refinery has a Nelson complexity index of 9.5 and a capacity is 276 kbpd of crude oil.
The Gdańsk refinery is an oil refinery located in Gdańsk formerly owned by Grupa Lotos, since 2022 owned by PKN Orlen. The refinery capacity is 210 kbpd of crude oil and it has a Nelson complexity index of 11.1.
Gaz-System, Operator Gazociągów Przesyłowych GAZ-SYSTEM S.A., is a designated natural gas transmission system operator in Poland. The company was established on 16 April 2004 as a wholly owned subsidiary of PGNiG under the name PGNiG – Przesył Sp. z o.o. On 28 April 2005, all shares of the company were transferred to the State Treasury of Poland and the current name of the company was adopted on 8 June 2005. Gaz-System owns and operates all gas transmission and distribution pipelines in Poland, except the Yamal–Europe pipeline owned by EuRoPol Gaz S.A. The company is also responsible for construction of the Polskie LNG terminal at Świnoujście and the Baltic Pipe pipeline between Poland and Denmark.
Naftoport Ltd () is a company which manages crude oil shipment and deliveries. It is located in Gdańsk. Naftoport Ltd was established in June 1991 by several Polish oil companies and Marine Commercial Port in Gdańsk. The company oversees operations of the terminal for reloading of crude oil and products in Port of Gdańsk.
PERN Przyjazn SA (), joint stock Oil Pipeline Operation Company "Przyjaźń" is one of leading companies for oil transportation and storage in Poland. The company is based in Płock and overlooks catering of oil and gas through Poland to eastern European markets.
Pipelines from the former Soviet Union
The Druzhba pipeline (; also has been referred to as the Friendship Pipeline and the Comecon Pipeline) is the world's longest oil pipeline and in fact one of the biggest oil pipeline networks in the world. It carries oil some from the eastern part of the European Russia to points in Ukraine, Belarus, Poland, Hungary, Slovakia, the Czech Republic and Germany. The network also branches out into numerous pipelines to deliver its product throughout the Eastern Europe and beyond. The name "Druzhba" means "friendship", alluding to the fact that the pipeline supplied oil to the energy-hungry western regions of the Soviet Union, to its "fraternal socialist allies" in the former Soviet bloc, and to western Europe. Today, it is the largest principal artery for the transportation of Russian (and Kazakh) oil across Europe.
The Odessa–Brody pipeline (also known as Sarmatia pipeline) is a crude oil pipeline between the Ukrainian cities Odessa at the Black Sea, and Brody near the Ukrainian-Polish border. There are plans to expand the pipeline to Płock, and furthermore to Gdańsk in Poland. The pipeline is operated by UkrTransNafta, Ukraine's state-owned oil pipeline company.
The Yamal–Europe pipeline is a long pipeline connecting natural gas fields in Western Siberia and in the future on the Yamal peninsula, Russia, with Germany.
Polski Gaz Sp z o. o. is a distributor of liquefied petroleum gas: propane and butane. Petrochemical Holding GMBH holds 100% share in Polski Gaz Sp. z o.o.
Protest
During summer 2013 "Occupy Chevron" protesters occupied the field near Żurawlów in the Grabowiec district where Chevron Corporation planned to drill an exploratory well. This type of activity is becoming more common.
References
External links and further reading
History of Polish Gas Industry
Mir-Babayev M.F. Brief history of the first drilled oil well; and people involved - "Oil-Industry History" (USA), 2017, v.18, #1, p. 25-34.
Energy in Poland
Natural gas in Poland
Petroleum in Poland | Oil industry in Poland | Chemistry | 2,695 |
628,991 | https://en.wikipedia.org/wiki/Adriaan%20van%20Roomen | Adriaan van Roomen (29 September 1561 – 4 May 1615), also known as Adrianus Romanus, was a mathematician, professor of medicine and medical astrologer from the Duchy of Brabant in the Habsburg Netherlands who was active throughout Central Europe in the late 16th and early 17th centuries. As a mathematician he worked in algebra, trigonometry and geometry; and on the decimal expansion of pi. He solved the Problem of Apollonius using a new method that involved intersecting hyperbolas. He also wrote on the Gregorian calendar reform.
Life
Van Roomen was born in Leuven, the son of Adriaan Van Roomen and Maria Van Den Daele. He was educated partly in Leuven and partly After studying at the Jesuit College in Cologne, also attending the University of Cologne where he began his study of medicine. He also briefly studied medicine at Leuven University. Roomen was professor of mathematics and medicine at Louvain from 1586 to 1592. He met Kepler, and discussed with François Viète two questions about equations and tangencies. He then spent some time in Italy, particularly with Clavius in Rome in 1585. His publication of 1595, Parvum theatrum urbium, contained Latin verse on the cities of Italy (possibly written by Thomas Edwards).
In June 1593 Van Roomen became the inaugural professor of medicine at the newly refounded University of Würzburg. He was also appointed physician in ordinary to the court of Rudolf II. From around 1595 to 1603 he produced calendars, almanacs and prognostications published under the patronage of Julius Echter, prince-bishop of Würzburg. At the same time, he served as mathematician of the king of Poland and become famous for the computation of the value of pi to sixteen decimals, surpassing François Viète who had arrived at ten digits. After being widowed he was ordained to the priesthood in 1604 and on 8 October 1608 was installed as a canon of the collegiate church of St John the Evangelist in Würzburg.
His Mathesis Polemica, published in Frankfurt in 1605, explained the military applications of mathematics. In June 1610 he was in Prague, after which he travelled to Poland at the invitation of Jan Zamoyski to give public lectures on mathematics at Zamość in Red Ruthenia. He made the return journey via Hungary, arriving back in Würzburg at the end of 1611.
Struggling with health problems, Van Roomen undertook a journey to Spa to take the waters but died en route at Mainz in the arms of his son, who was travelling with him.
See also
The Adriaan van Roomen affair
Zamojski Academy
Works
Ouranographia sive caeli descriptio (Leuven, Joannes Masius, 1591)
Ideae mathematicae pars prima, sive methodus polygonorum (Antwerp, Jan van Keerbergen, 1593)
Canon triangulorum rectangulorum, tam sphaericorum quam rectilineorum, methodo brevissima ([Leuven], 1593)
Supputatio Ecclesiastica Secundum novam et antiquam Calendarii rationem (Würzburg, 1595)
Parvum Theatrum Urbium (Frankfurt, Nicolaus Bassalus, 1595).
Almanack Wurztburger Bisthumbs, awff das Jar nach Christi unsers Seligmacher Geburt 1596 (Würzburg, Georgius Fleischmann, 1596)
In Archimedis circuli dimensionem expositio et analysis (Würzburg, 1597)
Newer und Alter Schreib Calender auf das M.D.XCVIII Jar (Würzburg, Georgius Fleischmann, 1598)
Newer und Alter Screib Calender Auff das MDXCIX Jar (Würzburg, Georgius Fleischmann, 1599)
Almanach Würtzburger Bisthumbs auff das Jar nach der heilsamen Geburt Jesu Christi MDC (Würzburg, Georgius Fleischmann, 1600)
Prognosticon Astrologicum oder Teutsche Practica auff das Jar nach der allein selichmachenden Geburt Unsers Heylands Jesu Christi M.DC. (Würzburg, Georgius Fleischmann, 1600)
Newer und Alter Schreib Calender auff das M.DCI. Jar (Würzburg, Georgius Fleischmann, 1601)
Prognosticon Astrologicum oder Teutsche Practica auff das Jar nach der Glorwürdigen Geburt Jesu Christi M.DCI. (Würzburg, Georgius Fleischmann, 1601)
Almanach Wurtzburger Bisthumbs auff dass Jar nach der heilsamen Geburt Jesu Christi M.DC.II. (Würzburg, Georgius Fleischmann, 1602)
Newer und Alter Schreib Calender auff das M.DC.II. Jar (Würzburg, Georgius Fleischmann, 1602)
Prognosticum astrologicum oder Teutsche Practica auff das M.DC.II. Jar (Würzburg, Georgius Fleischmann, 1602)
Universae mathesis idea (Würzburg, Georgius Fleischmann, 1602)
Chordarum arcubus circuli primariis (Würzburg, Georgius Fleischmann, 1602)
Newer und Alter Schreib Calender auff das M.DC.III. Jar (Würzburg, Georgius Fleischmann, 1603)
Prognosticon Astrologicum oder Teutsche Practica auff das Jar ... M.DC.III. (Würzburg, Georgius Fleischmann, 1603)
Arithmetica quatuor instrumenta nova Methodo ac forma patente exhibita (Würzburg, 1603)
Mathesis Polemica (Frankfurt, 1605)
Speculum Astronomicum sive Organum Forma Mappae Expressum (Leuven, Joannes Masius, 1606)
Canon triangulorum sphaericorum (Mainz, Joannis Albini, 1609)
Pyrotechnia, hoc est, de ignibus festivis, jocosis artificialibus et seriis, variisque eorum structuris libri duo (Frankfurt, Palthenius, 1611)
References
External links
1561 births
1615 deaths
16th-century Dutch mathematicians
17th-century Dutch mathematicians
Pi-related people
Scientists from Leuven
Catholic clergy scientists
Astronomers from the Spanish Netherlands | Adriaan van Roomen | Mathematics | 1,407 |
23,006,185 | https://en.wikipedia.org/wiki/Du%20Bois%20singularity | In algebraic geometry, Du Bois singularities are singularities of complex varieties studied by Du Bois.
Schwede gave the following characterisation of Du Bois singularities. Suppose that is a reduced closed subscheme of a smooth scheme .
Take a log resolution of in that is an isomorphism outside , and let be the reduced preimage of in . Then has Du Bois singularities if and only if the induced map is a quasi-isomorphism.
Notes
References
Singularity theory
Algebraic geometry | Du Bois singularity | Mathematics | 101 |
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