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  • postpartum pituitary necrosis (disease)

    Sheehan’s syndrome, insufficiency of pituitary hormones (hypopituitarism), caused by destruction of cells of the anterior pituitary gland by oxygen starvation, usually at the time of childbirth. The condition may also result from septic shock, burn shock, or a massive hemorrhage. Once the most

  • postploded nasal (speech sound)

    Austronesian languages: Phonetic types: …what might be called “postploded” nasals /-mb-/, /-nd-/, or /-ngg-/, in which a nasal consonant between vowels is followed by a stop that is almost too short to hear.

  • postposition (grammar)

    Turkic languages: Morphology: Postpositions, corresponding to English prepositions, are placed after the words they mark functionally—e.g., Turkish benden sonra ‘after me’ (literally ‘I-from after’), ev(in) önünde ‘in front of the house’ (literally ‘house-of front-its-at’). Conjunctions are used less frequently in Turkic languages than in English, and they are…

  • postprandial blood glucose test (biochemistry)

    glucose tolerance test: …screening test is the 2-hour postprandial blood glucose test. This test is performed 2 hours after intake of a standard glucose solution or a meal containing 100 grams of carbohydrates. A plasma glucose level above 140 mg/100 ml indicates the need for a glucose tolerance test.

  • postpubescent phase (physiology)

    human behaviour: Physiological aspects: The phase of postpubescence starts when pubic hair growth is complete, a deceleration of growth in height occurs, changes in the primary and secondary sexual characteristics are essentially complete, and the person is fertile. Some changes in primary and secondary sexual characteristics occur in this phase. For instance,…

  • postpunk (music)

    punk: Postpunk groups such as Public Image Ltd. and Joy Division replaced punk’s worldliness with inner concerns, matching rock with the technological rhythms of disco. Nevertheless, punk’s influence could be seen throughout British society, notably in mass media shock tactics, the confrontational strategies of environmentalists, and…

  • postreplication repair (biology)

    DNA repair: Postreplication repair occurs downstream of the lesion, because replication is blocked at the actual site of damage. In order for replication to occur, short segments of DNA called Okazaki fragments are synthesized. The gap left at the damaged site is filled in through recombination repair,…

  • Postromantic music

    Postromantic music, musical style typical of the last decades of the 19th century and first decades of the 20th century and characterized by exaggeration of certain elements of the musical Romanticism of the 19th century. Postromanticism exhibits extreme largeness of scope and design, a mixture of

  • Posts, Directorate of (French agency)

    postal system: France: …the farming system, a general Directorate of Posts attached to the Ministry of Finance was created in 1804. During the 19th century, the service developed to keep pace with the Industrial Revolution, notably through improvements in administration and transportation. The first French postage stamp was issued on January 1, 1849,…

  • PostScript (computer language)

    PostScript, a page-description language developed in the early 1980s by Adobe Systems Incorporated on the basis of work at Xerox PARC (Palo Alto Research Center). Such languages describe documents in terms that can be interpreted by a personal computer in order to display the document on its screen

  • postseason game (sports)

    gridiron football: Bowl games: In the 1920s and ’30s colleges and universities throughout the Midwest, South, and West, in alliance with local civic and business elites, launched campaigns to gain national recognition and economic growth through their football teams. They organized regional conferences—the Big Ten and the…

  • postsecondary education

    Higher education, any of various types of education given in postsecondary institutions of learning and usually affording, at the end of a course of study, a named degree, diploma, or certificate of higher studies. Higher-educational institutions include not only universities and colleges but also

  • poststructuralism

    Poststructuralism, movement in literary criticism and philosophy begun in France in the late 1960s. Drawing upon the linguistic theories of Ferdinand de Saussure, the anthropology of Claude Lévi-Strauss (see structuralism), and the deconstructionist theories of Jacques Derrida (see deconstruction),

  • postsynaptic potential (biology)

    Postsynaptic potential (PSP), a temporary change in the electric polarization of the membrane of a nerve cell (neuron). The result of chemical transmission of a nerve impulse at the synapse (neuronal junction), the postsynaptic potential can lead to the firing of a new impulse. When an impulse

  • postsynchronizing (cinema)

    Dubbing, in filmmaking, the process of adding new dialogue or other sounds to the sound track of a motion picture that has already been shot. Dubbing is most familiar to audiences as a means of translating foreign-language films into the audience’s language. When a foreign language is dubbed, the t

  • posttensioning (construction)

    bridge: Concrete: A typical process, called post-tensioned prestressing, involves casting concrete beams with longitudinal holes for steel tendons—cables or bars—like reinforced concrete, but the holes for the tendons are curved upward from end to end, and the tendons, once fitted inside, are stretched and then anchored at the ends. The tendons,…

  • postulate (mathematics)

    axiom: …listed in two categories, as postulates and as common notions. The former are principles of geometry and seem to have been thought of as required assumptions because their statement opened with “let there be demanded” (ētesthō). The common notions are evidently the same as what were termed “axioms” by Aristotle,…

  • Postum Cereal Co. Ltd. (American corporation)

    General Foods Corporation, former American manufacturer of packaged grocery and meat products. Since 1989, General Foods product lines have been sold by Kraft Foods Inc. The company was incorporated in 1922, having developed from the earlier Postum Cereal Co. Ltd., founded by C.W. Post (1854–1914)

  • Postumia (Slovenia)

    Postojna, city, western Slovenia, on the Pivka River northeast of Trieste (Italy). Long a local market centre, it is on the rail line and road from Trieste to Ljubljana, the capital of Slovenia. Its prime importance is as a tourist centre for its Postojna Cave, an internationally famous cave system

  • Postumus, Marcus Cassianius Latinius (Roman general)

    Marcus Cassianius Latinius Postumus, Roman general who, by setting himself up as an independent emperor in Gaul about 258–268 became a rival to the emperor Gallienus. Postumus and another general, Silvanus, stayed behind in Colonia (Cologne) with Gallienus’ son Saloninus after the emperor had left

  • posture

    African dance: Dance posture: There are three characteristic dance postures. An upright posture with a straight back is used as an expression of authority in the dance of chiefs and priests. In the second posture the dancer inclines forward from the hips, moving his attention and gestures toward…

  • postvelar consonant (phonology)

    Paleo-Siberian languages: Phonological features: …of the Paleo-Siberian languages are postvelar consonants (i.e., sounds that are formed farther back in the mouth than /k/ and usually represented as q), vowel harmony of various kinds (e.g., the alternation of e and i in the form for ‘my’ in Nivkh ñe-řla ‘my harpoon’ and ñi-řly ‘my sky’),…

  • Postville (Illinois, United States)

    Lincoln, city, seat (1853) of Logan county, central Illinois, U.S. It lies about 30 miles (50 km) northeast of Springfield. Founded in 1853, the city was named for Abraham Lincoln, then a Springfield attorney, who handled the legalities of its founding and christened it with the juice of a

  • postviral fatigue syndrome

    Chronic fatigue syndrome (CFS), disorder characterized by persistent debilitating fatigue. There exist two specific criteria that must be met for a diagnosis of CFS: (1) severe fatigue lasting six months or longer and (2) the coexistence of any four of a number of characteristic symptoms, defined

  • Pöstyén (Slovakia)

    Piešt’any, town, southwestern Slovakia, on the Váh River, approximately 48 miles (77 km) northeast of Bratislava. Piešt’any is a Carpathian health resort, known since the Middle Ages for its warm sulfur springs and mud baths. It has specialized since the 16th century in treating rheumatic and

  • Postyshev, Pavel (Soviet political leader)

    Ukraine: Russification: …was joined in 1933 by Pavel Postyshev as second secretary, who was sent from Moscow with a large contingent of Russian cadres. A series of purges from 1929 to 1934 largely eliminated from the party the generation of revolutionaries, supporters of Ukrainization, and those who questioned the excesses of collectivization.…

  • Postysheve (Ukraine)

    Krasnoarmiysk, city, eastern Ukraine. It is an old coal-mining centre of the Donets Basin coalfield, and mining began there in 1884. Other industries have included railway servicing and the production of construction materials. It is the centre of a significant agricultural area. Pop. (2001)

  • postzygapophyses (anatomy)

    snake: Vertebrae: …at two projections (prezygapophyses and postzygapophyses) from the centra, with articulating surfaces that lie above and below; and finally the zygosphenes and zygantra, found almost exclusively in snakes, the zygosphene being a projecting shelf on the upper part of the vertebra and the zygantrum being a pocket into which the…

  • postzygotic reproductive isolating mechanism (biology)

    evolution: Reproductive isolation: …take effect before fertilization, and postzygotic, those that take effect afterward. Prezygotic RIMs prevent the formation of hybrids between members of different populations through ecological, temporal, ethological (behavioral), mechanical, and gametic isolation. Postzygotic RIMs reduce the viability or fertility of hybrids or their progeny.

  • postzygotic RIM (biology)

    evolution: Reproductive isolation: …take effect before fertilization, and postzygotic, those that take effect afterward. Prezygotic RIMs prevent the formation of hybrids between members of different populations through ecological, temporal, ethological (behavioral), mechanical, and gametic isolation. Postzygotic RIMs reduce the viability or fertility of hybrids or their progeny.

  • posy (floral decoration)

    Nosegay, small, hand-held bouquet popular in mid- 19th-century Victorian England as an accessory carried by fashionable ladies. Composed of mixed flowers and herbs and edged with a paper frill or greens, the arrangement was sometimes inserted into a silver filigree holder. When supplied by an

  • pot (drug)

    Marijuana, crude drug composed of the leaves and flowers of plants in the genus Cannabis. The term marijuana is sometimes used interchangeably with cannabis; however, the latter refers specifically to the plant genus, which comprises C. sativa and, by some classifications, C. indica and C.

  • pot cheese (food technology)

    cottage cheese: …soft fresh cheese, usually called pot cheese, is produced in the same manner, but the curds are strained to remove most of the whey; thus, it is drier and less creamy than cottage cheese. The name pot cheese is sometimes used to refer to cottage cheese.

  • pot furnace (technology)

    industrial glass: Glass melting: …brought in the development of pot furnaces, which have remained almost unchanged even to this day. The pot furnaces were made of a plastic mixture of raw clay mixed well to remove bubbles. The pot floor was made first, before the sidewalls and the cover with a side opening were…

  • pot helm (armour)

    military technology: Mail: … with nasal evolved into the pot helm, or casque. This was an involved process, with the crown of the helmet losing its pointed shape to become flat and the nasal expanding to cover the entire face except for small vision slits and breathing holes. The late 12th-century helm was typically…

  • pot limit (betting structure)

    poker: Pot limit: In pot-limit contests, a player may bet or raise by no more than the amount in the pot at the time the bet or raise is made. When raising, the player may first put in the pot the number of chips required to…

  • pot marigold (plant)

    calendula: The pot marigold (Calendula officinalis) is grown especially for ornamental purposes and is commonly found in herbal products and cosmetics. The petal-like ray flowers are edible and are sometimes used in salads.

  • pot marjoram (herb)

    marjoram: Pot marjoram (O. onites) is also cultivated for its aromatic leaves and is used to flavour food. Oregano, or wild marjoram (O. vulgare), is a popular culinary herb native to Europe and Asia.

  • pot still (apparatus)

    distilled spirit: The pot still: The simple pot still is a large enclosed vessel, heated either by direct firing on the bottom or by steam coils within the vessel, with a cylindrical bulb at its top leading to a partially cooled vapour line. The bulb and vapour line separate…

  • pot-bellied stove

    stove: Its design influenced the potbellied stove, which was a familiar feature in some homes well into the 20th century. The first round cast-iron stoves with grates for cooking food on them were manufactured by Isaac Orr at Philadelphia, Pa., in 1800. The base-burning stove for burning anthracite coal was…

  • pot-roasting (cooking)

    braising: …of meat is sometimes called pot-roasting.

  • POT1 (protein)

    Thomas Robert Cech: …“protection of telomeres protein” (POT1) that caps the end of a chromosome, protecting it from degradation and ensuring the maintenance of appropriate telomere length. These discoveries had major implications in understanding the underlying mechanisms of cancer, as the disease was thought to be due in large part to the…

  • potager (vegetable garden)

    gardening: Herb and vegetable gardens: The old French potager, the prized vegetable garden, was grown to be decorative as well as useful; the short rows with little hedges around and the high standard of cultivation represent a model of the art of vegetable growing. The elaborate parterre vegetable garden at the Château de…

  • Potagos, Panayotis (Greek physician and explorer)

    Panayotis Potagos, physician and traveler attached to the Egyptian Service who explored the Uele River system in northern Congo (Kinshasa). Potagos began his travels in 1867, visiting Iraq, Iran, Afghanistan, the Gobi (desert, in China), and India. He arrived in Egypt in 1876 and began his African

  • Potala Palace (palace, Lhasa, Tibet, China)

    Potala Palace, immense religious and administrative complex in Lhasa, southern Tibet Autonomous Region, southwestern China. It is situated atop Mar-po-ri (Red Mountain), 425 feet (130 metres) above the Lhasa River valley, and rises up dramatically from its rocky base. Potrang Karpo (completed 1648;

  • Potamididae (gastropod family)

    gastropod: Classification: …families, including worm shells (Vermetidae), horn shells (Potamididae), and button shells (Modulidae). Superfamily Strombacea Foot and operculum greatly modified and move with a lurching motion; feed on algae and plants; some species used for human food; conchs (Strombidae) of tropical oceans and the pelican’s foot shells (Aporrhaidae

  • Potamochoerus porcus (mammal)

    Bush pig, (Potamochoerus porcus), African member of the family Suidae (order Artiodactyla), resembling a hog but with long body hair and tassels of hair on its ears. The bush pig lives in groups, or sounders, of about 4 to 20 animals in forests and scrub regions south of the Sahara. It is

  • Potamochoerus porcus porcus (mammal)

    Red river hog, African hoofed mammal, a subspecies of bush pig

  • Potamogale velox (mammal)

    otter shrew: The giant otter shrew (Potamogale velox) has the body form, fur texture, and coloration of a river otter but is smaller. It weighs less than 400 grams (0.9 pound) and has a body 27 to 33 cm (11 to 13 inches) long and a slightly shorter…

  • Potamogalinae (mammal)

    Otter shrew, (subfamily Potamogalinae), any of three species of amphibious and carnivorous tropical African insectivores that are not “true” shrews (family Soricidae). All are nocturnal and den in cavities and burrows in stream banks; tunnel entrances are underwater. Otter shrews have small eyes

  • Potamogeton crispus (plant)

    pondweed: …Europe and southern Asia, and P. crispus, of Europe but naturalized in the eastern United States and California. Cape pondweed, or water hawthorn (Aponogeton distachyos), of the family Aponogetonaceae, is native to South Africa and is grown as an ornamental in pools and greenhouses. Many species of those families serve…

  • Potamogeton densus (plant)

    pondweed: Potamogetonaceae includes frog’s lettuce (Potamogeton densus), of Europe and southern Asia, and P. crispus, of Europe but naturalized in the eastern United States and California. Cape pondweed, or water hawthorn (Aponogeton distachyos), of the family Aponogetonaceae, is native to South Africa and is grown as an ornamental…

  • Potamon fluviatile (crustacean)

    crab: Distribution and variety: …crab of southern Europe (the Lenten crab, Potamon fluviatile) is an example of the freshwater crabs abundant in most of the warmer regions of the world. As a rule, crabs breathe by gills, which are lodged in a pair of cavities beneath the sides of the carapace, but in the…

  • Potanin, Vladimir (Russian businessman)

    Mikhail Prokhorov: There he met Vladimir Potanin, who had worked for the foreign trade ministry and was eager to capitalize on the rapid privatization occurring as the Soviet Union collapsed in 1991.

  • Potaro River (river, Guyana)

    Guyana: Drainage: …tributaries of the Essequibo, the Potaro, the Mazaruni, and the Cuyuni drain the northwest, and the Rupununi drains the southern savanna. The coast is cut by shorter rivers, including the Pomeroon, the Mahaica, the Mahaicony, and the Abary.

  • potash (chemical compound)

    Potash, various potassium compounds, chiefly crude potassium carbonate. The names caustic potash, potassa, and lye are frequently used for potassium hydroxide (see potassium). In fertilizer terminology, potassium oxide is called potash. Potash soap is a soft soap made from the lye leached from wood

  • potash alum (chemical compound)

    alum: …aluminum sulfate, also known as potassium alum or potash alum, has a molecular formula of K2(SO4)·Al2(SO4)3·24H2O or KAl(SO4)2·12H2O.

  • potash clay (mineral)

    Hydrous mica, any of the illite group of clay minerals, including illite, bramallite (a sodium illite), and glauconite. They are structurally related to the micas; glauconite is also a member of the common-mica group. The hydrous micas predominate in shales and mudstones, but they also occur in

  • potash lye (chemical compound)

    potassium: …element (1807) by decomposing molten potassium hydroxide (KOH) with a voltaic battery.

  • potash mica (mineral)

    Muscovite, abundant silicate mineral that contains potassium and aluminum. Muscovite is the most common member of the mica group. Because of its perfect cleavage, it can occur in thin, transparent, but durable sheets. Sheets of muscovite were used in Russia for windowpanes and became known as

  • potash muriate (chemical compound)

    electricity: Electromotive force: …are connected electrically by a potassium chloride salt bridge. (A salt bridge is a conductor with ions as charge carriers.) In both kinds of batteries, the energy comes from the difference in the degree of binding between the electrons in copper and those in zinc. Energy is gained when copper…

  • Potash, Richard (American magician, actor, author, and historian)

    Ricky Jay, American magician, actor, author, and historian, widely regarded as the most gifted sleight-of-hand artist of his generation. He made his performing debut at age four during a backyard barbecue held by his grandfather Max Katz, then the president of the Society of American Magicians. By

  • Potash, Rikudah (Israeli author)

    Yiddish literature: Writers in Israel: Rikudah Potash was born in Poland and moved to Palestine in 1934. She published poetry in Poland and in Israel, including the volume Moyled iber Timna (1959; “New Moon over Timna”). Both her sense of fantasy and her knowledge of art history enrich this collection…

  • potassic series (geology)

    igneous rock: Classification of volcanic and hypabyssal rocks: …subdivided into the sodic and potassic series.

  • potassium (chemical element)

    Potassium (K), chemical element of Group 1 (Ia) of the periodic table, the alkali metal group, indispensable for both plant and animal life. Potassium was the first metal to be isolated by electrolysis, by the English chemist Sir Humphry Davy, when he obtained the element (1807) by decomposing

  • potassium alum (chemical compound)

    alum: …aluminum sulfate, also known as potassium alum or potash alum, has a molecular formula of K2(SO4)·Al2(SO4)3·24H2O or KAl(SO4)2·12H2O.

  • potassium aluminosilicate (chemical compound)

    alkali feldspar: of sodium aluminosilicate (NaAlSi3O8) and potassium aluminosilicate (KAlSi3O8). Both the sodium and potassium aluminosilicates have several distinct forms, each form with a different structure. The form stable at high temperatures is sanidine (a sodium aluminosilicate), which has a random distribution of aluminum and silicon atoms in its crystal structure. Low-temperature…

  • potassium borate (chemical compound)

    inorganic polymer: Borates: …chains of B2O42− units, whereas potassium borate, K[B5O6(OH)4] · 2H2O (commonly written as KB5O8 · 4H2O), consists of two B3O3 rings linked through a common four-coordinated boron atom. The tetraborates, B4O5(OH)42−, contain both three- and four-coordinated boron surrounded trigonally and tetrahedrally, respectively, by oxygen (O) atoms. Commercially, the

  • potassium bromate (chemical compound)

    bromine: Production and use: Traces of potassium bromate (KBrO3) are added to wheat flour to improve baking. Other bromine compounds of significance include hydrogen bromide (HBr), a colourless gas used as a reducing agent and a catalyst in organic reactions. A solution of the gas in water is called hydrobromic acid,…

  • potassium bromide (chemical compound)

    spectroscopy: Infrared instrumentation: … (ZnSe), cesium iodide (CsI), or potassium bromide (KBr), coated with silicon or germanium are employed. Below 200 cm−1 Mylar films of varying thickness are used to cover narrow portions of the region. Thermal detection of infrared radiation is based on the conversion of a temperature change, resulting from such radiation…

  • potassium channel (biology)

    nervous system: Potassium channels: There are several types of voltage-dependent potassium channels, each having its own physiological and pharmacological properties. A single neuron may contain more than one type of potassium channel.

  • potassium chlorate (chemical compound)

    match: …(1) oxidizing agents, such as potassium chlorate, which supply oxygen to the igniting agent and the other combustible materials; (2) binders, such as animal glue, starches and gums, and synthetics, which bind the ingredients and are oxidized during combustion; post-combustion binders, such as ground glass, which fuse and hold the…

  • potassium chloride (chemical compound)

    electricity: Electromotive force: …are connected electrically by a potassium chloride salt bridge. (A salt bridge is a conductor with ions as charge carriers.) In both kinds of batteries, the energy comes from the difference in the degree of binding between the electrons in copper and those in zinc. Energy is gained when copper…

  • potassium chromate (chemical compound)

    titration: …be done is by employing potassium chromate as indicator. Potassium chromate reacts with the first slight excess silver ion to form a red precipitate of silver chromate. Another method involves the use of an adsorption indicator, the indicator action being based on the formation on the surface of the precipitate…

  • potassium cyanide (chemical compound)

    wet-collodion process: …of sodium thiosulfate, for which potassium cyanide was later substituted. Immediate developing and fixing were necessary because, after the collodion film had dried, it became waterproof and the reagent solutions could not penetrate it. The process was valued for the level of detail and clarity it allowed. A modification of…

  • potassium cyanoaurate (chemical compound)

    gold: Compounds: Potassium cyanoaurate, K[Au(CN)2], is the basis for most gold-plating baths (the solution employed when gold is plated). Several organic compounds of gold have industrial applications. For example, gold mercaptides, which are obtained from sulfurized terpenes, are dissolved in certain organic solutions and used for decorating…

  • potassium deficiency (pathology)

    Potassium deficiency, condition in which potassium is insufficient or is not utilized properly. Potassium is a mineral that forms positive ions (electrically charged particles) in solution and is an essential constituent of cellular fluids. The relationship between potassium and the metabolism of

  • potassium dihydrogen phosphate (chemical compound)

    electricity: Electro-optic phenomena: …for its Pockels effect is potassium dihydrogen phosphate, which has good optical properties and low dielectric losses even at microwave frequencies.

  • potassium ethyl xanthate (chemical compound)

    xanthate: …in reference to the compound potassium ethyl xanthate (C2H5OCS2K), which gives a yellow precipitate when combined with copper sulfate. The most important group of xanthates are the sodium salts produced from cellulose; these materials are processed to form the synthetic fibre rayon or the transparent film cellophane, then reconverted to…

  • potassium feldspar (mineral)

    feldspar: Chemical composition: Microcline and orthoclase are potassium feldspars (KAlSi3O8), usually designated Or in discussions involving their end-member composition. Albite (NaAlSi3O8—usually designated Ab) and anorthite (CaAl2Si2O8—An) are end-members of the plagioclase series. Sanidine, anorthoclase, and the perthites are alkali feldspars whose chemical compositions lie between Or and Ab.

  • potassium ferricyanide (chemical compound)

    blueprint: …of ferric ammonium citrate and potassium ferricyanide, which is then exposed to light. In the areas of the sensitized paper not obscured by the lines of the drawing, the light reduces the ferric salt to the ferrous state, in which it reacts with the potassium ferricyanide to form insoluble prussian…

  • potassium hexachloroplatinate (chemical compound)

    coordination compound: History of coordination compounds: …of a sparingly soluble compound, potassium hexachloroplatinate(2−), K2[PtCl6], to refine the element platinum.

  • potassium hydroxide (chemical compound)

    potassium: …element (1807) by decomposing molten potassium hydroxide (KOH) with a voltaic battery.

  • potassium intoxication (pathology)

    fluid: Potassium intoxication, which may follow upon kidney failure, causes reduction in the volume of urine excreted, producing symptoms much like those of potassium depletion. Treatment is by elimination of potassium-rich foods (especially fruits) and protein from the diet.

  • potassium iodide (chemical compound)

    chemical compound: Binary ionic compounds: In

  • potassium nitrate (chemical compound)

    saltpetre: Ordinary saltpetre.: Potassium nitrate occurs as crusts on the surface of the Earth, on walls and rocks, and in caves; and it forms in certain soils in Spain, Italy, Egypt, Iran, and India. The deposits in the great limestone caves of Kentucky, Virginia, and Indiana have probably…

  • potassium nitrite (chemical compound)

    ham: Sodium or potassium nitrite, which inhibits the growth of the botulism-causing bacterium Clostridium botulinum and fixes the colour of the meat, is also used in curing; these additives became the subject of controversy in the late 20th century when studies linked them to a possible carcinogen-forming process…

  • potassium ozonide (chemical compound)

    ozonide: …ion O-3; an example is potassium ozonide (KO3), an unstable, orange-red solid formed from potassium hydroxide and ozone that, upon heating, decomposes into oxygen and potassium superoxide (KO2).

  • potassium permanganate (chemical compound)

    carboxylic acid: Oxidation: …common being chromic acid (H2CrO4), potassium permanganate (KMnO4), and nitric acid (HNO3). Aldehydes are oxidized to carboxylic acids more easily (by many oxidizing agents), but this is not often useful, because the aldehydes are usually less available than the corresponding acids. Also important is the oxidation of alkyl side chains…

  • potassium sulfate (chemical compound)

    potassium: Principal compounds and reactions with other elements: …leather and dyeing textiles; and potassium sulfate, K2SO4, which is used in the production of fertilizers and potassium alums.

  • potassium superoxide (chemical compound)

    potassium: Properties, occurrence, and uses: …combustion in dry air to potassium superoxide, KO2, which is used in respiratory equipment because it liberates oxygen and removes carbon dioxide and water vapour. (The superoxide of potassium is a yellow solid consisting of K+and O2− ions. It also can be formed by oxidation of potassium amalgam with dry…

  • potassium wasting syndrome (pathology)

    Bartter syndrome, any of several rare disorders affecting the kidneys and characterized primarily by the excessive excretion of potassium in the urine. Bartter syndrome is named after American endocrinologist Frederic Bartter, who described the primary characteristics of the disorder in the early

  • potassium-40 (physics)

    radioactivity: Calculation and measurement of energy: …of naturally occurring but radioactive potassium-40 is measured to be 39.964008 amu. Potassium-40 decays predominantly by β-emission to calcium-40, having a measured mass 39.962589. Through Einstein’s equation, energy is equal to mass (m) times velocity of light (c) squared, or E = mc2, the energy release (Q) and the mass…

  • potassium-argon dating

    Potassium-argon dating, method of determining the time of origin of rocks by measuring the ratio of radioactive argon to radioactive potassium in the rock. This dating method is based upon the decay of radioactive potassium-40 to radioactive argon-40 in minerals and rocks; potassium-40 also decays

  • potassium-cesium binary system (chemistry)

    potassium: Properties, occurrence, and uses: …exists in the potassium-rubidium and potassium-cesium binary systems. The latter system forms an alloy melting at approximately −38 °C (−36 °F). Modification of the system by the addition of sodium results in a ternary eutectic melting at approximately −78 °C (−108 °F). The composition of this alloy is 3 percent…

  • potassium–sparing diuretic (drug)

    drug: Renal system drugs: The potassium-sparing diuretics block the exchange processes in the distal tubule and thus prevent potassium loss. Sometimes a mixture of diuretics is used in which a thiazide is taken together with a potassium-sparing diuretic to prevent excess potassium loss. In other instances, the potassium loss may…

  • Potatau I (Maori king)

    Maori: The rise of the King Movement: …Te Wherowhero, who reigned as Potatau I. In addition to electing a king, they established a council of state, a judicial system, and a police organization, all of which were intended to support Maori resolve to retain their land and to stop the intertribal warfare over the issue. Not all…

  • potato (plant)

    Potato, (Solanum tuberosum), annual plant in the nightshade family (Solanaceae), grown for its starchy edible tubers. The potato is native to the Peruvian-Bolivian Andes and is one of the world’s main food crops. Potatoes are frequently served whole or mashed as a cooked vegetable and are also

  • potato aphid (insect)

    aphid: Types of aphids: The potato aphid (Macrosiphum euphorbiae) begins as black eggs on rose plants, which hatch into pink and green young that feed on rosebuds and leaves. In early spring they migrate to potatoes, which are the summer host. One generation occurs every two to three weeks. It…

  • potato bean (plant)

    groundnut: …nut; Apois americana, also called wild bean and potato bean, the tubers of which are edible; and Lathyrus tuberosa, also called earth-nut pea. Cyperus esculentus, nut sedge or yellow nut grass, is a papyrus relative (family Cyperaceae) that also bears edible tubers, especially in the variety called chufa or earth…

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