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Polyptych of the Misericordia (work by Piero della Francesca)
Back in Sansepolcro by 1442, Piero was elected to the town council. Three years later the Confraternita della Misericordia commissioned a polyptych from him. The Misericordia Altarpiece shows Piero’s indebtedness to the Florentines Donatello and Masaccio, his fondness for geometric form, and the slowness and deliberation with which he habitually worked—for the Misericordia altarpiece...
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polyrhythm (music)
the simultaneous combination of contrasting rhythms in a musical composition. Rhythmic conflicts, or cross-rhythms, may occur within a single metre (e.g., two eighth notes against triplet eighths) or may be reinforced by simultaneous combinations of conflicting metres. The latter effect is characteristic of numerous n...
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polysaccharide (chemical compound)
the form in which most natural carbohydrates occur. Polysaccharides may have a molecular structure that is either branched or linear. Linear compounds such as cellulose often pack together to form a rigid structure; branched forms (e.g., gum arabic) generally are ...
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Polyscias fruticosa (plant)
...of palmately divided, glossy green leaves do best in a light and warm location. Another picturesque plant is Polyscias fruticosa, the Ming aralia, with willowy, twisting stems densely clothed toward their tops with fernlike, lacy foliage....
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polysilicate (mineral)
any member of a group of compounds with structures that have silicate tetrahedrons (a central silicon atom surrounded by four oxygen atoms at the corners of a tetrahedron) arranged in a three-dimensional lattice. Each of the four oxygen atoms of a given tetrahedron is shared with another tetrahedron. Each tetrahedron, therefore, is linked to f...
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polysiloxane (chemical compound)
any of a diverse class of fluids, resins, or elastomers based on polymerized siloxanes, substances whose molecules consist of chains made of alternating silicon and oxygen atoms. Their chemical inertness, resistance to water and oxidation, and stability at both high and low temperature...
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Polysiphonia (algae genus)
...to coral reefs and coral sands; predominantly marine; approximately 4,100 described species; Bangia, Palmaria, Polysiphonia, Porphyra, and Rhodymenia. Robert A.......
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polyspermy (biology)
...causes a change in the egg membrane(s), so that the attachment of and penetration by more than one spermatozoon cannot occur. In species in which more than one spermatozoon normally enters an egg (polyspermy), only one spermatozoal nucleus actually merges with the egg nucleus. The most important result of fertilization is egg activation, which allows the egg to undergo cell division.......
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Polystichum (plant genus)
...sporangia with the annulus vertical; spores monolete (more or less bean-shaped); 45 genera with about 1,700 species, the largest genera, Dryopteris (log fern, about 250 species), Polystichum (shield fern, about 250 species), and Elaphoglossum (tongue fern, 600–700 species), distributed nearly worldwide.Family......
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Polysticta stelleri (bird)
...sporangia with the annulus vertical; spores monolete (more or less bean-shaped); 45 genera with about 1,700 species, the largest genera, Dryopteris (log fern, about 250 species), Polystichum (shield fern, about 250 species), and Elaphoglossum (tongue fern, 600–700 species), distributed nearly worldwide.Family......
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Polystoechotidae (insect)
...with many teeth. Larvae elongated; long, slender, straight jaws, slightly upcurved; in margins of fresh water.Family Polystoechotidae (large lacewings)Adults medium to large; wing expanse 40–75 mm; antennae short. Larvae with short, sharp, incurved mandibles, maxillae stout, blunt; labial p...
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polystylism (music)
...Russian composer who created serious, dark-toned musical works characterized by abrupt juxtapositions of radically different, often contradictory, styles, an approach that came to be known as “polystylism.”...
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polystyrene (chemical compound)
a hard, stiff, brilliantly transparent synthetic resin produced by the polymerization of styrene. It is widely employed in the food-service industry as rigid trays and containers, disposable eating utensils, and foamed cups, plates, and bowls. Polystyrene is also copolymerized, or blended with other polymers, lending hardn...
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polysulfide (chemical compound)
any member of a class of chemical compounds containing one or more groups of atoms of the element sulfur linked together by covalent bonds. In inorganic compounds belonging to t...
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polysulfide rubber (chemical compound)
Polysulfide rubber was discovered in 1926 by an American chemist, Joseph Cecil Patrick, while he was attempting to obtain ethylene glycol for use as an antifreeze. The elastomer was commercialized under the trade name Thiokol (after the Greek theion, “brimstone” [sulfur] and kommi, “gum”), which......
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polysulfone (chemical compound)
any of a class of resinous organic chemical compounds belonging to the family of polymers in which the main structural chain most commonly consists of benzene rings linked together by sulfonyl (−SO2−), ether (−O−), and isopropyliden...
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Polysynodie (French history)
...induced the Parlement (high court of justice) of Paris to annul Louis XIV’s will (Sept. 12, 1715). He then proceeded to institute an experimental system of conciliar government—known as la polysynodie—designed to destroy the authority of the secretaries of state and restore political power to the high nobility. T...
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polysynthesis (linguistics)
...units that compose such a word are “bound” forms (i.e., cannot be used except in conjunction with other elements within a word), the process has gone beyond agglutination and is called polysynthesis, a process characteristic of many American Indian languages. Some Hokan languages are extremely polysynthetic, among them the Yana...
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Polytechnic Institute of Brooklyn (university, New York City, New York, United States)
...visiting the United States, where he decided to remain. In 1930 he became a visiting professor at the Polytechnic Institute of Brooklyn (now Polytechnic University) in New York City, where he rose through various academic posts to become head of research and graduate study in electrical......
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Polytechnic University (university, New York City, New York, United States)
...visiting the United States, where he decided to remain. In 1930 he became a visiting professor at the Polytechnic Institute of Brooklyn (now Polytechnic University) in New York City, where he rose through various academic posts to become head of research and graduate study in electrical......
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Polytechnical Museum (museum, Moscow, Russia)
in Moscow, museum of science and technology that emphasizes the history of Soviet science and technology and contemporary developments and inventions. The museum was founded in 1872 after the first Russian technical exhibition on the bicentennial anniversary of the birth of Peter the Great. The building housing the museum was completed in 1877. It includes some foreign exhibitions....
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polyterpene (chemical compound)
Rubber, which occurs in the latex of the rubber tree, is a polyterpene hydrocarbon, (C5H8)n, in which n is 4,000–5,000. Chemical degradation by oxidation and X-ray diffraction studies have revealed a repeating unit in rubber. Division into isoprene units is indicated....
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polytetrafluoroethylene (chemical compound)
a strong, tough, waxy, nonflammable synthetic resin produced by the polymerization of tetrafluoroethylene. Known by such trademarks as Teflon, Fluon, Hostaflon, and Polyflon, PTFE is distinguished by its slippery surface, high melting point, and resistance to attack by almost all chemicals. These properties have made it fa...
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polytetrahydrofuran (chemical compound)
Polyethers of this type, which include polyethylene oxide, polypropylene oxide, and polytetrahydrofuran, are flexible and relatively noncrystalline. Because they have alcohol groups at the chain ends, they are sometimes called polyether glycols. Indeed, alternative names for the first......
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polytheism
the belief in many gods. Polytheism characterizes virtually all religions other than Judaism, Christianity, and Islam, which share a common tradition of monotheism, the belief in one God....
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polythene (chemical compound)
light, versatile synthetic resin made from the polymerization of ethylene. Polyethylene is a member of the important family of polyolefin resins. It is the most widely used plastic in the world, being made into products ranging from clear food wrap and shopping bags to detergent bottles and automobile fu...
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polythermal glacier
...water, it is customary to classify glaciers in terms of their thermal condition. A polar glacier is defined as one that is below the freezing temperature throughout its mass for the entire year; a subpolar (or polythermal) glacier contains ice below the freezing temperature, except for surface melting in the summer and a basal layer of......
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polythiazyl (chemical compound)
...the two most interesting ones are tetrasulfur tetranitride, S4N4, and disulfur dinitride, S2N2, because they are precursors to an unusual polymer called polythiazyl, (SN)x. This polymeric sulfur nitride is unusual because, even though it is composed solely of two nonmetals, it exhibits some properties normally associated only with......
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polytonality (music)
in music, the simultaneous occurrence of two or more different tonalities or keys (the interrelated sets of notes and chords used in a composition). If only two keys are employed, the term bitonality is sometimes used....
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polytope (mathematics)
A (convex) polytope is the convex hull of some finite set of points. Each polytope of dimensions d has as faces finitely many polytopes of dimensions 0 (vertices), 1 (edge), 2 (2-faces), · · · , d-1 (facets). Two-dimensional polytopes are usually called polygons, three-dimensional ones polyhedra. Two......
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Polytrichidae (moss subclass)
...often thick-walled and supportive, while the inner cells are generally larger and have thinner walls. Some mosses, however, have considerable tissue differentiation in the stem. In the moss subclass Polytrichidae, for example, a complex conducting strand is often formed in the centre of the stem. It consists of an internal cylinder of water-conducting cells (the hydroids) surrounded by layers o...
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Polytrichum (moss)
any of the plants of the genus Polytrichum (subclass Bryidae) with 39–100 species; it often forms large mats in peat bogs, old fields, and areas with high soil acidity. About 10 species are found in North America. The most widely distributed species is P. commune, which often attains a height of 15 cm (6...
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Polytrichum commune (plant species)
...peat bogs, old fields, and areas with high soil acidity. About 10 species are found in North America. The most widely distributed species is P. commune, which often attains a height of 15 cm (6 inches) or more and may form large tussocks or wide beds, especially in peat bogs. The reddish brown or dark green phyllids (leaves), often 1...
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polytype (crystallography)
...involves one-dimensional variations, but the latter generally three-dimensional ones. The variety of structures resulting from different stacking sequences of a fixed chemical composition are termed polytypes. If such a variety is caused by ionic substitutions that are minor but consistent, they are called polytypoids....
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polytypic species (biology)
...that all of these now genetically isolated populations arose as local differentiations of a single stock; thus, they are now usually classed in zoological usage as subspecies of one polytypic species. The term polytypic indicates that a separate description (and type specimen) is needed for each of the distinct populations,......
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polyunsaturated acid (chemical compound)
Fatty acids containing more than one carbon-carbon double bond (polyunsaturated fatty acids) are found in relatively minor amounts. The multiple double bonds are almost always separated by a CH2 group (−CH2−CH=CH−CH2−CH=CH−CH2−), a......
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polyunsaturated fatty acid (chemical compound)
Fatty acids containing more than one carbon-carbon double bond (polyunsaturated fatty acids) are found in relatively minor amounts. The multiple double bonds are almost always separated by a CH2 group (−CH2−CH=CH−CH2−CH=CH−CH2−), a......
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polyuranate (chemistry)
...in acidic solutions produced by the ion-exchange or solvent-extraction processes described above, as well as uranium dissolved in carbonate ore leach solutions, is typically precipitated as a polyuranate. From acidic solutions, uranium is precipitated by addition of neutralizers such as sodium hydroxide, magnesia, or (most commonly)......
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polyurethane (chemical compound)
any of a class of synthetic resinous, fibrous, or elastomeric compounds belonging to the family of organic polymers made by the reaction of diisocyanates (organic compounds containing two functional groups of structure −NCO) with other difunctional compounds such as glycols. The best known polyurethanes are flexible ...
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polyuria (medical disorder)
...but not necessarily, associated with frequency of urination. This in turn may represent either an irritable or contracted bladder; or the actual amount of urine formed may be unusually large (polyuria), in which case voiding is likely to be painless. Sometimes polyuria may not be noticed by day but may manifest itself in the need to micturate on several occasions during the night......
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polyvinyl acetate (chemical compound)
a synthetic resin prepared by the polymerization of vinyl acetate. In its most important application, polyvinyl acetate serves as the film-forming ingredient in water-based (latex) paints; it also is used in adhesives....
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polyvinyl alcohol (chemical compound)
a colourless, water-soluble synthetic resin employed principally in the treating of textiles and paper....
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polyvinyl butyral (chemical compound)
...taken out in France by an artist and chemist, Édouard Bénédictus, who used a sheet of celluloid bonded between two pieces of glass. Other plastics were also tried, but in 1936 polyvinyl butyral (PVB) was found to possess so many safety-desirable properties that its use became universal. Bulletproof glass is usually built up using several glass and plastic components....
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polyvinyl chloride (chemical compound)
a synthetic resin made from the polymerization of vinyl chloride. Second only to polyethylene among the plastics in production and consumption, PVC is used in an enormous range of domestic and industrial products, from raincoats and shower curtains t...
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polyvinyl compound (chemical compound)
...the U.S. for this type of flooring. In the U.K. the term asphalt tile was used for a different product, and the somewhat misleading term thermo-plastic tile was applied to a similar British product. Vinyl asbestos tiles, containing asbestos fibres, were developed next and introduced at the Chicago World’s Fair in 1933, but resin shortages prevented quantity production until 1948. Vinyl, ...
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polyvinyl fluoride (chemical compound)
a synthetic resin produced by polymerizing vinyl fluoride (CH2=CHF) under pressure in the presence of catalysts. A tough, transparent plastic resistant to attack by chemicals or by weathering, it is commonly manufactured in the form of a film and applied as a protective coating for outdoor surfaces such as build...
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polyvinyl formal (chemical compound)
...three other industrial polymers begins with PVAc. Polyvinyl alcohol (PVA), a water-soluble polymer employed in textile and paper treatment, is made by hydrolyzing PVAc. Polyvinyl butyral (PVB) and polyvinyl formal (PVF) are manufactured from PVA by reaction with butyraldehyde (CH3CH2CH2CHO) and formaldehyde (CH2O), respectively. PVB is employed as a.....
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polyvinylidene chloride (chemical compound)
a synthetic resin produced by the polymerization of vinylidene chloride. It is used principally in clear, flexible, and impermeable plastic food wrap....
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polyvinylidene fluoride (chemical compound)
a synthetic resin produced by the polymerization of vinylidene fluoride (CH2=CF2). A tough plastic that is resistant to flame, electricity, and attack by most chemicals, PVDF is injection-molded into bottles for the chemical industry and extruded ...
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polywater (chemistry)
liquid water generally formed by condensation of water vapour in tiny glass or fused-quartz capillaries and with properties very different from those well established for ordinary water; e.g., lower vapour pressure, lower freezing temperature, higher density and v...
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Polyxena (Greek mythology)
in Greek mythology, a daughter of Priam, king of Troy, and his wife, Hecuba. After the fall of Troy, she was claimed by the ghost of Achilles, the greatest of the Greek warriors, as his share of the spoils and was therefore put to death at his tomb. In post-Classical times the story was elaborated; it was said that a peace h...
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polyxene (mineral)
...British Columbia, and in Alberta. Placer deposits are the most productive sources of the native element. The ordinary variety of native platinum is called polyxene; it is 80 percent to 90 percent platinum, with 3 percent to 11 percent iron, plus the other platinum metals, and gold, copper, and nickel. For mineralogical properties, see native......
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Polyxenus (arthropod genus)
...to a point opposite the female’s genital pore. Paired body projections then are used to inject the sperm into the female, and the pellet is dropped. Males of the common bark-inhabiting millipede Polyxenus transfer sperm by spinning thin threads on which they place sperm drops; they then construct two parallel thicker threads on which they place a pheromone to attract the female. T...
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Polyzoa (invertebrate)
any member of the phylum Bryozoa (also called Polyzoa or Ectoprocta), in which there are about 5,000 extant species. Another 15,000 species are known only from fossils. As with brachiopods and phoronids, bryozoans possess a peculiar ring of ciliated tentacles, called a lophophore, for collecting food particles suspended in the water. The bryozoans are a widely distributed, aquatic, invertebrate gr...
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polyzoan (invertebrate)
any member of the phylum Bryozoa (also called Polyzoa or Ectoprocta), in which there are about 5,000 extant species. Another 15,000 species are known only from fossils. As with brachiopods and phoronids, bryozoans possess a peculiar ring of ciliated tentacles, called a lophophore, for collecting food particles suspended in the water. The bryozoans are a widely distributed, aquatic, invertebrate gr...
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polyzoic religion (religion)
Each of these categories (i.e., nature or spiritualistic–ethical) may be further subdivided. At the earliest and lowest stage of spiritual development was polyzoic religion, about which there is no information but which is based on Tiele’s theory that man must have regarded natural phenomena as endowed with life and superhuman magical power. The first known stage of the nature...
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POM (chemical compound)
Also called polyoxymethylene (POM) or simply acetal, polyacetal has the simplest structure of all the polyethers. It is manufactured in a solution process by anionic or cationic chain-growth polymerization of formaldehyde (H2C=O), a reaction analogous to vinyl polymerization. By itself, the polymer is unstable and reverts to monomer on heating to 120° C (250°......
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pom-pom-pullaway (game)
...players must run from one safety zone to another across a central area where the chaser waits for them (this game is known as black peter in central Europe, wall-to-wall in Great Britain, and pom-pom-pullaway in the United States). In addition, there are also freeze tag and group tag. With freeze tag, the tagged person cannot move......
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Poma de Ayala, Felipe Guamán (Peruvian author and illustrator)
native Peruvian author and illustrator of El primer nueva corónica y buen gobierno (1612–15; “The First New Chronicle and Good Government”)....
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Pomacanthidae (fish family)
The brightly coloured marine angelfishes seen among tropical reefs are members of the family Pomacanthidae. Sometimes placed with the similar butterfly fishes in the family Chaetodontidae, they are compressed, deep-bodied fishes with small mouths and rather rough scales; the largest grows about 46 cm (18 inches) long. These angelfishes are......
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Pomacanthus arcuatus (fish)
Among the better-known species are the black and gold angelfish (Centropyge bicolor) of the Indo-Pacific; the French angelfish, Pomacanthus paru (or P. arcuatus), a black and yellow species of the Atlantic; and the queen angelfish (......
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Pomacanthus imperator (fish species)
Among the better-known species are the black and gold angelfish (Centropyge bicolor) of the Indo-Pacific; the French angelfish, Pomacanthus paru (or P. arcuatus), a black and yellow species of the Atlantic; and the queen angelfish (.........
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Pomacanthus paru (fish)
Among the better-known species are the black and gold angelfish (Centropyge bicolor) of the Indo-Pacific; the French angelfish, Pomacanthus paru (or P. arcuatus), a black and yellow species of the Atlantic; and the queen angelfish (......
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pomace (residue)
The drained pomace (crushed mass remaining after extraction of the juice from the grapes), from white or red fermentations, may be used to provide distilling material for production of wine spirits. Water is usually added, the fermentation is completed, and the low-alcohol wine is drained off. The pomace may be further washed and pressed or may be distilled directly in special stills....
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pomace fly (insect)
any member of a genus in the small fruit fly family, Drosophilidae (order Diptera). Drosophila species number about 1,500. Some species, particularly D. melanogaster, are used extensively in laboratory and field experiments on genetics and evolution because they are easy to raise and have a short life cycle (le...
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Pomacea (snail genus)
...land snail, the African Achatina achatina, forms a shell that is almost 20 centimetres (eight inches) long. The largest freshwater snails, Pomacea from South America, reach nearly 10 centimetres in diameter, and the largest marine......
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Pomacentridae (fish)
any of about 250 species of small, primarily tropical marine fishes of the family Pomacentridae (order Perciformes) found in the Atlantic and Indo-Pacific oceans. Damselfishes are deep-bodied and usually have forked tails. They resemble the related cichlids and, like them, have a single nostril on each side of the head and have interrupted lateral lines. Damselfishes have two anal spines. Many spe...
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Pomacentrus (fish)
Better-known members of the family include the bright-coloured species of Pomacentrus, the black-and-white, or three-stripe, damselfish (Dascyllus aruanus) of the Indo-Pacific; the garibaldi (Hypsypops rubicundus), a bright orange California fish about 30 cm long; the beau gregory (......
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pomade (cosmetic)
...During this time most of the flower oil is absorbed by the fat. The petals are then removed (defleurage), and the process is repeated until the fat is saturated with oil. The final product is called pomade (e.g., pomade de jasmine). ...
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Pomak (people)
...second largest city, the largest port after Piraeus, and the administrative, industrial, and commercial centre of northern Greece. Fewer than 20,000 Muslims remain in the region, those being mostly Pomaks, a Turkicized people speaking a Bulgarian dialect. Vlachs are concentrated in the cities of Thessaloníki and Sérrai (Sérres), Macedonians (who speak their own South Slavic...
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pomander (container)
small metal (sometimes china) container designed to hold a ball of aromatic spices or herbs. Worn suspended from neck or girdle or attached to the finger by a ring, it was believed to be a protection against infections and noxious smells. As fashionable jewelry in the late Middle Ages, pomanders were decorative objects often enriched with gems and enamels. Late in the 16th century, the original s...
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Pomare II (Tahitian chief)
...in 1788. The first permanent European settlers (1797) were members of the Protestant London Missionary Society, who helped the local Pomare family gain control of the entire island. Tahitian chief Pomare II (1803–24) embraced Christianity in 1815, triumphed over the other Tahitian rulers, and established a “missionary” kingdom with a scriptural code of law. However, the......
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Pomare, Sir Maui (Maori statesman)
Maori statesman and physician whose public-health work helped revive New Zealand’s Maori population, which had declined nearly to extinction by the late 19th century....
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Pomare, Sir Maui Wiremu Pita Naera (Maori statesman)
Maori statesman and physician whose public-health work helped revive New Zealand’s Maori population, which had declined nearly to extinction by the late 19th century....
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Pomares, Anita (American actress)
American film actress who briefly shone as one of Hollywood’s top stars during the transition from silent films to talkies, starting with a role as a doomed jazz baby in the 1928 silent picture Our Dancing Daughters. Other notable films include While the City Sleeps (1928), The Flying Fleet (1929), and the early talkie The Broadway Melody (1929), which won the Ac...
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Pomaria (Algeria)
town, northwestern Algeria, near the Moroccan border. Tlemcen is backed by the cliffs of the well-watered Tlemcen Mountains and overlooks the fertile Hennaya and Maghnia plains. Lying at an elevation of 2,648 feet (807 metres), Tlemcen is located sufficiently inland to avoid the humidity of the Mediterranean coast but is near enough to receive cooling sea breezes in summer. The resulting ...
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pomarine jaeger (bird)
The largest species is the pomarine jaeger, or pomatorhine skua (Stercorarius pomarinus), 50 cm (20 inches) long. Smallest is the long-tailed jaeger (S. longicaudus), 35 cm (14 inches) long. Intermediate in body size is the parasitic......
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pōmata (religious textile design)
...in the Eastern Orthodox churches. It is open down the front but fastened at the neck and at the hem. At the point where the neck and hem are fastened, the bishop’s mandyas is decorated with pōmata (Greek: “beverages”), richly embroidered squares of material. Red and white stripes called potamoi (Greek: “rivers”) flow out from the squares. ...
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Pomatiasidae (gastropod family)
...LittorinaceaPeriwinkles, on rocky shores (Littorinidae) of all oceans; land snails of the West Indies, part of Africa, and Europe (Pomatiasidae).Superfamily RissoaceaSmall to minute, generally cylindrical, marine, freshwater and land snails found in most tropical and......
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Pomatomus saltatrix (fish)
(Pomatomus saltatrix), swift-moving marine food and game fish, the only member of the family Pomatomidae (order Perciformes). The bluefish ranges through warm and tropical regions of the Atlantic and Indian oceans, living in schools and preying with voracity on other, smaller animals, especially fishes. Elongated in f...
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pomatorhine skua (bird)
The largest species is the pomarine jaeger, or pomatorhine skua (Stercorarius pomarinus), 50 cm (20 inches) long. Smallest is the long-tailed jaeger (S. longicaudus), 35 cm (14 inches) long. Intermediate in body size is the parasitic......
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Pomatorhinidae (bird family)
scimitar babbler family of noisy birds, based on the genus Pomatorhinus—in this encyclopaedia classified as part of the babbler family (Timaliidae)....
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Pomatostomatidae (bird)
...entrance. Bold brown, rufous black and white plumage colours. 3 species. Rainforests of Australia and New Guinea.Family Pomatostomatidae (Australo-Papuan babblers)Medium-sized terrestrial songbirds, 18–25 cm (7–10 inches), with long bills and tails, like mockingbirds (Mimidae) of the...
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Pombal, Sebastião de Carvalho, marquês de (Portuguese ruler)
Portuguese reformer and virtual ruler of his country from 1750 to 1777....
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Pombal, Sebastien (Portuguese ruler)
Portuguese reformer and virtual ruler of his country from 1750 to 1777....
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pombo (African sculpture)
...minsere. Large, ugly gongoli masks are also used, but entirely for entertainment. In preparing their rice farms, the Mende often uncover figures carved in soapstone and known as nomoli, which they set up in shelters to protect the crop. The figures are similar in style and are thought to be similar in date to ivories carved in the 16th century for Portuguese traders in......
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Pombo, Álvaro (Spanish author)
...naufragio (1980; “Beached After the Last Shipwreck”; Eng. trans. Stranded), all of which explore the solitude of middle-aged women and their deceptions in love. Pombo, originally known as a poet, turned later to the novel; El metro de platino iradiado (1990; “The Metre of Irradiated Platinum”) is considered by many his masterpie...
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POMC (biochemistry)
Corticotropin, also called adrenocorticotropin (ACTH), is a segment of a much larger glycoprotein prohormone molecule called proopiomelanocortin (POMC). Proopiomelanocortin is synthesized by the corticotrophs of the anterior pituitary, which constitute about 10 percent of the gland. Proopiomelanocortin is split into several biologically active polypeptides when the secretory granules are......
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pome (plant anatomy)
...seed (peaches, plums, and cherries). The term druplet is used for each unit of aggregate fruit of this type (e.g., raspberries and blackberries). Pomes are fleshy fruits of the rose family (Rosaceae) in which an adnate hypanthium becomes fleshy (apples and pears)....
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pomegranate (plant)
fruit of Punica granatum, a bush or small tree of Asia, which with a little-known species from the island of Socotra constitutes the family Punicaceae. The plant, which may attain 5 or 7 metres (16 or 23 feet) in height, has elliptic to lance-shaped, bright-green leaves about 75 millimetres (3 inches) long and handso...
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pomelo (fruit)
(Citrus paradisi), citrus tree of the Rutaceae family and its edible fruit. The grapefruit tree grows to be as large and vigorous as an orange tree; a mature tree may be from 4.5 to 6 metres (15 to 20 feet) high. The foliage is very dense, with leaves dark and shiny green and nearly glabrous. Flowers are large, white...
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Pomerania (historical region, Europe)
historic region of northeastern Europe lying along the Baltic coastal plain between the Oder and the Vistula rivers. Politically, the name also came to include the area west of the Oder as far as Stralsund, including the island of Rügen (Rugia). Most of Pomerania is now part of Poland, but its westernmost section is in eastern Germany, ...
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Pomerania Ulterior (region, Poland)
Eastern Pomerania was held by the Teutonic Knights from 1308 to 1454, when it was reconquered by Poland. In 1772 it was annexed by Prussia and made into the province of West Prussia. A small part of it was restored to Poland after World War I; the remainder, together with part of Pomerania, became Polish in 1945. The German population of......
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Pomeranian (people)
Pomerania was inhabited successively by Celts, Germanic tribes, and, by the 5th century ad, the Slavic Pomeranians (Pomorzanie) and Polabs. Mieszko I, prince of Poland (d. 992), mastered it, and in 1000 his successor, Bolesław I the Brave, organized a diocese in Pomerania with its seat at Kołobrzeg. A local dynasty ...
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Pomeranian (breed of dog)
breed of toy dog that can be traced back, like the related Keeshond, Samoyed, and Norwegian elkhound, to early sled-dog ancestors. The breed is named for the duchy of Pomerania, where, in the early 19th century, it is said to have been bred down in size from a 30-pound (13.5-kg) sheepdog. Characteristically spirited but do...
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Pomeranian Lakeland (region, Poland)
lake district, northwestern Poland. Located immediately south of the Baltic coastal plain, the 20,000-square-mile (52,000-square-km) lakeland is bounded by the lower Oder River on the west, the ancient river valley occupied by the modern Warta and Noteć rivers on ...
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Pomeranian language (language)
...however, the language has nasalized vowels (spelled ę and ą), indirectly continuing the nasalized vowels of early Slavic. Among the major dialects are Great Polish and Pomeranian, Silesian, Little Polish, and Mazovian. Kashubian (Cassubian), often classified as a Polish dialect, is, historically, a separate language....
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Pomerium (work by Marchettus of Padua)
...a number of writers who refer to “Italian Ars Nova,” which is also known as Italian trecento music. The most important theorist of this school was Marchettus of Padua, whose treatise Pomerium (in the early 14th century) outlines certain rhythmic innovations in Italian notation of the time. The most important composers of 14th-century Italy are Jacopo da Bologna, ......
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pomerium (sacred ground, ancient Rome)
(from Latin post-moerium, “behind the wall”), in ancient Rome, a sacred open space located just inside the wall surrounding the four hills—the Esquiline, the Palatine, the Quirinal, and the Capitoline—of the early city. In most Italian walled cities, such spaces, which ran along the comple...
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Pomeroon River (river, Guyana)
...coast. Among the tributaries of the Essequibo, the Potaro, Mazaruni, and Cuyuni drain the northwest, and the Rupununi drains the southern savanna. The coast is cut by shorter rivers, including the Pomeroon, Mahaica, Mahaicony, and Abary....
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