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  • praying mantid (insect)

    Mantid, (family Mantidae), any of approximately 2,000 species of large, slow-moving insects that are characterized by front legs with enlarged femurs (upper portion) that have a groove lined with spines into which the tibia (lower portion) presses. Using their spined front legs, mantids, which feed

  • praying mantis (insect)

    Mantid, (family Mantidae), any of approximately 2,000 species of large, slow-moving insects that are characterized by front legs with enlarged femurs (upper portion) that have a groove lined with spines into which the tibia (lower portion) presses. Using their spined front legs, mantids, which feed

  • Praz, Mario (Italian literary critic and essayist)

    Mario Praz, Italian literary critic and essayist, a preeminent scholar of English literature. Praz was educated at the University of Bologna (1914–15) before receiving degrees from the Universities of Rome (1918) and Florence (1920). He then studied at the British Museum in London (1923–25) and

  • praziquantel (drug)

    anthelmintic: Cestode anthelmintics: Praziquantel also produces tetanus-like contractions of the musculature of the worm. Unlike albendazole, praziquantel is readily absorbed from the intestinal tract. It is a broad-spectrum anthelmintic affecting both flukes and tapeworms.

  • prazo (feudal estate)

    Prazo, any of the great feudal estates acquired by Portuguese and Goan traders and soldiers in the valley of the Zambezi River in what is now Mozambique. Begun in the 16th century as an attempt at colonization, the prazo system was formalized in the mid-17th century. While giving titular obedience

  • Pražský hrad (castle, Prague, Czech Republic)

    Prague Castle, collective name for an aggregation of palaces, churches, offices, fortifications, courtyards, and gardens in Prague, covering approximately 110 acres (45 hectares). The castle was formerly the seat of the kings of Bohemia and is currently the official residence of the president of

  • PRC (Liberian government)

    Samuel K. Doe: …of general and established a People’s Redemption Council (PRC) composed of himself and 14 other low-ranking officers to rule the country. Doe suspended the nation’s constitution until 1984, when a new constitution was approved by referendum. In 1985 he won a presidential election that was denounced as fraudulent by some…

  • PRC (American company)

    Detour: Although Detour was made by Producers Releasing Corporation, one of several studios that specialized in cheaply made B-films, and thus was a “poverty row” movie, it has the distinction of being the first such film to be preserved in the National Film Registry of the Library of Congress. Shot in…

  • PRC 1 (satellite)

    China 1, first Earth satellite orbited by the People’s Republic of China. It was launched on April 24, 1970, from the rocket facility at Shuang Cheng Tsu, and it made China the fifth nation to place a satellite into Earth orbit. Little is known about China 1. It weighed approximately 173 kg (381

  • PRCA (American organization)

    rodeo: Origins and history: …(RCA) in 1945 and the Professional Rodeo Cowboys Association (PRCA) in 1975, and its rules became accepted by most rodeos.

  • PRD (political party, Mexico)

    Andrés Manuel López Obrador: …Cárdenas’s electoral coalition, the centre-left Party of the Democratic Revolution (PRD).

  • PRD (political party, Panama)

    Ricardo Martinelli: …the candidate of the ruling Democratic Revolutionary Party (Partido Revolucionario Democrático; PRD), Balbina Herrera, was considered the favourite, but Martinelli’s campaign promise of “real change” resonated among poor voters. Moreover, he already had the support of many of Panama’s business leaders. He won by a wide margin, garnering some 60…

  • PRD (political party, Switzerland)

    FDP. The Liberals, centrist political party of Switzerland formed in 2009 by the merger of the Radical Democratic Party (German: Freisinnig-Demokratische Partei der Schweiz [FDP]) and the Liberal Party (German: Liberale Partei der Schweiz [LPS]). FDP. The Liberals assumed the role previously held

  • PRD (political party, Dominican Republic)

    Juan Bosch: …in 1939 founded the leftist Dominican Revolutionary Party (Partido Revolucionario Dominicano; PRD). The PRD was the first well-organized political party of the Dominican Republic and the only one with a constructive program ready to implement after Trujillo’s death in 1961. Bosch, a dazzling and charismatic orator, won a landslide victory…

  • Pre Rup (mountain, Indonesia)

    Southeast Asian arts: Kingdom of Khmer: 9th–13th century: Pre Rup, dedicated in 961, was probably the first of the temple mountains intended as a permanent shrine for the divine spirit of a king after his death. It, too, has a quincunx of principal shrines, but it is distinguished by the large number of…

  • Pre-Boreal Climatic Interval (geology)

    Stone Age: Neolithic: …late Dryas period during the Pre-Boreal and the Boreal (c. 8000–5500 bce, determined by radiocarbon dating) caused a remarkable change in late glacial flora and fauna. Thus, the Mediterranean zone became the centre of the first cultural modifications leading from the last hunters and food gatherers to the earliest farmers.…

  • Pre-Ceramic period (archaeological period)

    Japanese art: Formative period: …that of a Paleolithic, or Pre-Ceramic, stage dating from approximately 30,000 bce (although some posit an initial date as early as 200,000 bce); the Jōmon period (c. 10,500–c. 3rd century bce), variously subdivided; the Yayoi period (c. 3rd century bce–c. 250 ce); and the Tumulus, or Kofun, period (c. 250–710…

  • pre-Chalcedonian church (Christianity)

    Christmas: Contemporary customs in Eastern and Oriental Orthodoxy: The churches of the Oriental Orthodox communion celebrate Christmas variously. For example, in Armenia, the first country to adopt Christianity as its official religion, the church uses its own calendar; the Armenian Apostolic Church honours January 6 as Christmas. In Ethiopia, where Christianity has had a home ever since…

  • Pre-Chimú (ancient South American culture)

    Moche, Andean civilization that flourished from the 1st to the 8th century ce on the northern coast of what is now Peru. The name is taken from the great site of Moche, in the river valley of the same name, which appears to have been the capital or chief city of the Moche peoples. Their settlements

  • pre-Classic people (Mesoamerican history)

    American Indian: Early cultural development: Known to archaeologists as Formative or pre-Classic peoples, these groups established agricultural villages by 1800 bce. From this point until the beginning of the Common Era, Formative peoples such as the Olmec built large towns and developed increasingly complex architecture, art, and religion.

  • pre-Classical Chinese language

    Chinese languages: Pre-Classical Chinese: The history of the Chinese language can be divided into three periods, pre-Classical (c. 1500 bc–c. ad 200), Classical (c. 200–c. 1920), and post-Classical Chinese (with important forerunners as far back as the Tang dynasty).

  • Pre-Classical period (art history)

    Archaic period, in history and archaeology, the earliest phases of a culture; the term is most frequently used by art historians to denote the period of artistic development in Greece from about 650 to 480 bc, the date of the Persian sack of Athens. During the Archaic period, Greek art became less

  • Pre-Columbian American religions

    sacrament: Sacramental ideas and practices of pre-Columbian America: The recurrent and widespread practice of holding sacred meals in the sacramental system, in addition to being well documented in the Greco-Roman world, also occurred in the pre-Columbian Mexican calendrical ritual in association with human sacrifice on a grand scale. In the May…

  • pre-Columbian civilizations

    Pre-Columbian civilizations, the aboriginal American Indian cultures that evolved in Mesoamerica (part of Mexico and Central America) and the Andean region (western South America) prior to Spanish exploration and conquest in the 16th century. The pre-Columbian civilizations were extraordinary

  • pre-emphasis (electronics)

    sound recording: The phonograph disc: …the plastic disc—a process called pre-emphasis. Upon playback this sequence is reversed in a process called equalization, providing the listener with a linear and realistic sound.

  • pre-exposure prophylaxis (medicine)

    AIDS: Condoms, vaccines, gels, and other prevention methods: Research has indicated that preexposure prophylaxis (PrEP), in which uninfected persons take an antiretroviral pill daily, can be highly effective in preventing infection. PrEP studies conducted in Kenya, Uganda, and Botswana, for example, revealed that the Truvada pill, which contains the antiretroviral medications tenofovir and emtricitabine, reduced the risk…

  • Pre-historic Times (work by Lubbock)

    archaeology: First steps to archaeology: … coined it in his book Pre-historic Times (1865).

  • Pre-Hittite period (Anatolian history)

    Anatolian art and architecture: Pre-Hittite period: Anatolian excavations have done much to illuminate the genesis of visual arts in the earliest settled communities. In a Neolithic setting, at Çatalhüyük in the Konya plain, a township covering more than 15 acres (6 hectares) and dating from…

  • Pre-Lent (Christianity)

    church year: Roman Catholic Church: …of Time, the season of Pre-Lent was eliminated, and two cycles were provided: (1) the principal seasons, Sundays, and holy days from Advent to Pentecost and (2) a schedule of 33 Sundays per annum to be observed in numbered sequence in place of the Sundays previously designated “after Epiphany” and…

  • pre-mRNA (genetics)

    transcription: …of transcription is called a pre-mRNA. Pre-mRNA is extensively edited through splicing before the mature mRNA is produced and ready for translation by the ribosome, the cellular organelle that serves as the site of protein synthesis. Transcription of any one gene takes place at the chromosomal location of that gene,…

  • pre-Phanerozoic time (geochronology)

    Precambrian, period of time extending from about 4.6 billion years ago (the point at which Earth began to form) to the beginning of the Cambrian Period, 541 million years ago. The Precambrian encompasses the Archean and Proterozoic eons, which are formal geologic intervals that lasted from 4

  • Pre-Raphaelite Brotherhood

    Pre-Raphaelite Brotherhood, group of young British painters who banded together in 1848 in reaction against what they conceived to be the unimaginative and artificial historical painting of the Royal Academy and who purportedly sought to express a new moral seriousness and sincerity in their works.

  • Pre-Raphaelite Movement

    Pre-Raphaelite Brotherhood, group of young British painters who banded together in 1848 in reaction against what they conceived to be the unimaginative and artificial historical painting of the Royal Academy and who purportedly sought to express a new moral seriousness and sincerity in their works.

  • Pre-Romanticism (European history)

    Pre-Romanticism, cultural movement in Europe from about the 1740s onward that preceded and presaged the artistic movement known as Romanticism (q.v.). Chief among these trends was a shift in public taste away from the grandeur, austerity, nobility, idealization, and elevated sentiments of

  • pre-Socratics (Greek philosophy)

    Pre-Socratics, group of early Greek philosophers, most of whom were born before Socrates, whose attention to questions about the origin and nature of the physical world has led to their being called cosmologists or naturalists. Among the most significant were the Milesians Thales, Anaximander, and

  • Preacher, The (Old Testament)

    Ecclesiastes, (Preacher), an Old Testament book of wisdom literature that belongs to the third section of the biblical canon, known as the Ketuvim (Writings). In the Hebrew Bible, Ecclesiastes stands between the Song of Solomon and Lamentations and with them belongs to the Megillot, five scrolls

  • Preachers, Order of (religious order)

    Dominican, one of the four great mendicant orders of the Roman Catholic Church, founded by St. Dominic in 1215. Its members include friars, nuns, active sisters, and lay Dominicans. From the beginning the order has been a synthesis of the contemplative life and the active ministry. The members live

  • preaching (religion)

    oratory: …Greek and Roman rhetoric was religious oratory. For more than 1,000 years after Cicero the important orators were churchmen rather than politicians, lawyers, or military spokesmen. This tradition derived from the Judaean prophets, such as Jeremiah and Isaiah, and in the Christian Era, from the Apostle Paul, his evangelistic colleagues,…

  • Preah Bat Samdech Preah Norodom Sihanouk (king of Cambodia)

    Norodom Sihanouk, twice king of Cambodia (1941–55 and 1993–2004), who also served as prime minister, head of state, and president. He attempted to steer a neutral course for Cambodia in its civil and foreign wars of the late 20th century. Sihanouk was, on his mother’s side, the grandson of King

  • Preah Vihear, Temple of (temple, Cambodia)

    Cambodia: Cultural institutions: In 2008 the Temple of Preah Vihear, dedicated to the worship of Shiva, was also named a World Heritage site.

  • Preahreacheanachakr Kampuchea

    Cambodia, country on the Indochinese mainland of Southeast Asia. Cambodia is largely a land of plains and great rivers and lies amid important overland and river trade routes linking China to India and Southeast Asia. The influences of many Asian cultures, alongside those of France and the United

  • Preakness Stakes (American horse race)

    Preakness Stakes, a 1316-mile (about 1,900-metre) flat race for three-year-old Thoroughbred horses, held at Pimlico Race Course, Baltimore, Maryland, U.S., annually in mid-May. Fillies carry 121 pounds (55 kg), colts 126 pounds (57 kg). The Preakness Stakes is the second (and shortest) race of the

  • preamble (diplomacy)

    treaty: The preamble provides the names and styles of the contracting parties and is a statement of the treaty’s general objectives. It is usually followed by the articles containing the agreed-upon stipulations. If the treaty is concluded for a definite period, a statement of the period follows;…

  • Preanger (region, Indonesia)

    Indonesia: Growth and impact of the Dutch East India Company: …received the cession of the Preanger regions of western Java.

  • Preanger stelsel (Dutch revenue system)

    Preanger system, revenue system introduced in the 18th century in Preanger (now Priangan) of western Java (now part of Indonesia) by the Dutch East India Company and continued by the Dutch until 1916. In this system the company required its regents to deliver specified annual quotas of coffee but l

  • Preanger system (Dutch revenue system)

    Preanger system, revenue system introduced in the 18th century in Preanger (now Priangan) of western Java (now part of Indonesia) by the Dutch East India Company and continued by the Dutch until 1916. In this system the company required its regents to deliver specified annual quotas of coffee but l

  • prebendal (feudalism)

    primitive culture: European peasant society: These workers are called prebendal in English (French provendiers) because they were provisioned and housed at the master’s expense. The only difference between a prebendal worker and a slave was the freedom of the prebendal worker to leave if he was dissatisfied.

  • prebiotic (nutrition)

    nutraceutical: Diverse groups of nutraceuticals: …lactating women, and probiotic and prebiotic yogurt. (Prebiotics are nondigestible nutrients that serve as an energy source for bacteria that assist with the breakdown of food in the human digestive tract.)

  • Prebisch, Raúl (Argentine economist and statesman)

    Raúl Prebisch, Argentine economist and statesman. Serving in various positions in Argentine government and academia, he advised developing countries to stimulate domestic manufacturing to reduce their reliance on imports and thus their dependence on the industrialized nations. He also advocated the

  • Preble, Edward (United States naval commander)

    Edward Preble, commander of U.S. naval forces during the most active portion of the Tripolitan War (1801–05). The son of provincial military officer, merchant, and political leader Jedidiah Preble and of Mehetable Bangs Roberts, Edward Preble received his early education in his native Falmouth and

  • Preboreal Climatic Interval (geology)

    Stone Age: Neolithic: …late Dryas period during the Pre-Boreal and the Boreal (c. 8000–5500 bce, determined by radiocarbon dating) caused a remarkable change in late glacial flora and fauna. Thus, the Mediterranean zone became the centre of the first cultural modifications leading from the last hunters and food gatherers to the earliest farmers.…

  • Preboreal stage (geology)

    Stone Age: Neolithic: …late Dryas period during the Pre-Boreal and the Boreal (c. 8000–5500 bce, determined by radiocarbon dating) caused a remarkable change in late glacial flora and fauna. Thus, the Mediterranean zone became the centre of the first cultural modifications leading from the last hunters and food gatherers to the earliest farmers.…

  • Precambrian (geochronology)

    Precambrian, period of time extending from about 4.6 billion years ago (the point at which Earth began to form) to the beginning of the Cambrian Period, 541 million years ago. The Precambrian encompasses the Archean and Proterozoic eons, which are formal geologic intervals that lasted from 4

  • Precambrian Eon (geochronology)

    Precambrian, period of time extending from about 4.6 billion years ago (the point at which Earth began to form) to the beginning of the Cambrian Period, 541 million years ago. The Precambrian encompasses the Archean and Proterozoic eons, which are formal geologic intervals that lasted from 4

  • Precambrian Eonothem (stratigraphy)

    Africa: The Precambrian: The oldest rocks consist of gneisses, granites, metasediments, and metavolcanic rocks 3.6 to 2.5 billion years old; all are variably deformed and metamorphosed to some degree. The best-preserved assemblages occur in the Kaapvaal and Zimbabwe cratons and contain large deposits of gold and sulfide…

  • Precambrian Shield (shield, North America)

    Canadian Shield, one of the world’s largest geologic continental shields, centred on Hudson Bay and extending for 8 million square km (3 million square miles) over eastern, central, and northwestern Canada from the Great Lakes to the Canadian Arctic and into Greenland, with small extensions into

  • Precambrian time (geochronology)

    Precambrian, period of time extending from about 4.6 billion years ago (the point at which Earth began to form) to the beginning of the Cambrian Period, 541 million years ago. The Precambrian encompasses the Archean and Proterozoic eons, which are formal geologic intervals that lasted from 4

  • Precambrian-Cambrian transition

    Cambrian Period: Fossil record of the Precambrian-Cambrian transition: The preservation of the record of the Precambrian-Cambrian transition was significantly affected by global changes in sea level. During latest Precambrian time, the sea level was relatively low, resulting in spatially restricted oceans and expanded continents. Throughout much of the Cambrian, rising seas…

  • precapillary (anatomy)

    capillary: …intermediate vessels called precapillaries, or metarterioles, that, unlike the capillaries, have muscle fibres that permit them to contract; thus the precapillaries are able to control the emptying and filling of the capillaries.

  • precarious (philosophy)

    John Dewey: The precarious: For Dewey, a precarious event is one that somehow makes ongoing experience problematic; thus, any obstacle, disruption, danger, or surprise of any kind is precarious. As noted earlier, because humanity is a part of nature, all things that humans encounter in their daily…

  • precarious contract (feudalism)

    France: Diffusion of political power: …duration of his life) and precarious contract (a powerful lord received certain services in return for the use of his land for a limited time under advantageous conditions). In the 8th century the Pippinids increased their personal circle of followers. Charlemagne sought to establish a personal bond with the entire…

  • precast concrete (construction)

    Precast concrete, Concrete cast into structural members under factory conditions and then brought to the building site. A 20th-century development, precasting increases the strength and finish durability of the member and decreases time and construction costs. Concrete cures slowly; the design

  • Precaution (novel by Cooper)

    James Fenimore Cooper: Early years: Precaution (1820) was a plodding imitation of Jane Austen’s novels of English gentry manners. It is mainly interesting today as a document in the history of American cultural colonialism and as an example of a clumsy attempt to imitate Jane Austen’s investigation of the ironic…

  • precautionary principle (government)

    Precautionary principle, approach in policy making that legitimizes the adoption of preventative measures to address potential risks to the public or environment associated with certain activities or policies. The concept of the precautionary principle emerged in the 1970s–80s in German

  • precava (anatomy)

    vena cava: …of two major trunks, the anterior and posterior venae cavae, that deliver oxygen-depleted blood to the right side of the heart. The anterior vena cava, also known as the precava, drains the head end of the body, while the posterior vena cava, or postcava, drains the tail, or rear, end.…

  • precedent (law)

    Precedent, in law, a judgment or decision of a court that is cited in a subsequent dispute as an example or analogy to justify deciding a similar case or point of law in the same manner. Common law and equity, as found in English and American legal systems, rely strongly on the body of established

  • precentor (religious occupation)

    library: The role of the European monasteries: …under the supervision of a precentor, one of whose duties was to issue the books and take daily inventory of them. Scriptoria, the places where manuscripts were copied out, were a common feature of the monasteries—again, especially in those of the Benedictine order, where there was a strict obligation to…

  • Precepts of Jesus, the Guide to Peace and Happiness (work by Roy)

    Ram Mohan Roy: Early life: …four Gospels, under the title Precepts of Jesus, the Guide to Peace and Happiness.

  • Precepts of Traditional Chinese Medicine, The

    In one of the spectacles for the opening ceremonies of the XXIX Olympiad in Beijing on Aug. 8, 2008, more than 2,000 performers appeared to float onto the performance area while carrying out the graceful movements of taijiquan. Many spectators in the global audience outside China may have been

  • precession (physics)

    Precession, phenomenon associated with the action of a gyroscope or a spinning top and consisting of a comparatively slow rotation of the axis of rotation of a spinning body about a line intersecting the spin axis. The smooth, slow circling of a spinning top is precession, the uneven wobbling is

  • precession method of X-ray diffraction analysis (physics)

    Martin Julian Buerger: …of Buerger’s innovations is the precession method of X-ray diffraction analysis (the determination of the spatial arrangement of atoms in crystals by observing the pattern in which they scatter a beam of X rays), one of the two most commonly used methods of recording diffraction intensities.

  • prechlorination (water treatment)

    water purification: Pretreatment: Prechlorination, which is often the final step of pretreatment and a standard practice in many parts of the world, has been questioned by scientists. During the prechlorination process, chlorine is applied to raw water that may contain high concentrations of natural organic matter. This organic…

  • Précieuses ridicules, Les (work by Molière)

    Molière: Early life and beginnings in theatre: …play, Les Précieuses ridicules (The Affected Young Ladies), prefigured what was to come. It centres on two provincial young women who are exposed by valets masquerading as masters in scenes that contrast, on the one hand, the women’s desire for elegance coupled with a lack of common sense and,…

  • Précieux Sang, Hôtel-Dieu du (hospital, Quebec, Canada)

    hospital: History of hospitals: …1639 at Quebec city, the Hôtel-Dieu du Précieux Sang, which is still in operation (as the Hôtel-Dieu de Québec), although not at its original location. In 1644 Jeanne Mance, a French noblewoman, built a hospital of ax-hewn logs on the island of Montreal; this was the beginning of the Hôtel-Dieu…

  • préciosité (literature)

    Preciosity, style of thought and expression exhibiting delicacy of taste and sentiment, prevalent in the 17th-century French salons. Initially a reaction against the coarse behaviour and speech of the aristocracy, this spirit of refinement and bon ton was first instituted by the Marquise de R

  • preciosity (literature)

    Preciosity, style of thought and expression exhibiting delicacy of taste and sentiment, prevalent in the 17th-century French salons. Initially a reaction against the coarse behaviour and speech of the aristocracy, this spirit of refinement and bon ton was first instituted by the Marquise de R

  • Precious Bane (novel by Webb)

    Precious Bane, novel by Mary Webb, published in 1924. The story is set in the wild countryside near the Welsh border and is narrated by Prudence Sarn, a young woman whose life has been disrupted by her physical deformity, a cleft lip. Prudence’s defect forces her to develop an inner strength that

  • precious cat’s-eye (gemstone)

    Cymophane, variety of the gemstone chrysoberyl

  • precious coral (invertebrate)

    cnidarian: Annotated classification: Worldwide; includes precious red coral, Corallium. Order Trachylina Medusa dominant; reduced or no polyp stage. Statocysts and special sensory structures (tentaculocysts). Differ from other hydromedusae by having tentacles inserted above umbrellar margin. Oceanic, mostly warmer waters. Suborder Laingiomedusae Medusae with

  • precious garnet (mineral)

    Almandine, either of two semiprecious gemstones: a violet-coloured variety of ruby spinel (q.v.) or iron aluminum garnet, which is most abundant of the garnets. Specimens of the garnet, frequently crystals, contain up to 25 percent grossular or andradite and are commonly brownish red; gem-quality

  • precious metal (mineralogy)

    Asia: Precious metals: Many Asian countries have produced gold from alluvial stream deposits in past centuries, and some have continued to do so. Small volumes of alluvial gold are produced in Myanmar, Cambodia, and Indonesia, and the headwaters of the Yangtze River in the Tibetan border…

  • precious olivine (gemstone)

    Peridot, gem-quality, transparent green olivine in the forsterite–fayalite series (q.v.). Gem-quality olivine has been valued for centuries; the deposit on Jazīrat Zabarjad (Saint Johns Island), Egypt, in the Red Sea that is mentioned by Pliny in his Natural History (ad 70) still produces fine

  • precious red coral (invertebrate)

    cnidarian: Annotated classification: Worldwide; includes precious red coral, Corallium. Order Trachylina Medusa dominant; reduced or no polyp stage. Statocysts and special sensory structures (tentaculocysts). Differ from other hydromedusae by having tentacles inserted above umbrellar margin. Oceanic, mostly warmer waters. Suborder Laingiomedusae Medusae with

  • Precious: Based on the Novel ‘Push’ by Sapphire (film by Daniels [2009])

    Sapphire: Push was filmed as Precious: Based on the Novel ‘Push’ by Sapphire (2009).

  • precipitate (materials)

    crystal: Crystal defects: These inclusions are called precipitates and constitute a large defect.

  • precipitation

    Chemical precipitation, formation of a separable solid substance from a solution, either by converting the substance into an insoluble form or by changing the composition of the solvent to diminish the solubility of the substance in it. The distinction between precipitation and crystallization

  • precipitation (weather)

    Precipitation, all liquid and solid water particles that fall from clouds and reach the ground. These particles include drizzle, rain, snow, snow pellets, ice crystals, and hail. (This article contains a brief treatment of precipitation. For more-extensive coverage, see climate: Precipitation.) The

  • precipitation hardening (industrial process)

    metallurgy: Increasing strength: …on the same scale as precipitation hardening can be created by plastically deforming the metal at room temperature. This is often done in a cold-working operation such as rolling, forging, or drawing. The deformation occurs through the generation and motion of line defects, called dislocations, on slip planes spaced only…

  • precipitation heat treating (metallurgy)

    metallurgy: Hardening treatments: Aging is done at an elevated temperature that is still well below the temperature at which the precipitate will dissolve. If the alloy is heated still further, the precipitate will coarsen; that is, the finest particles will dissolve so that the average particle size will…

  • precipitation reaction (chemistry)

    sample preparation: Isolation and preconcentration: …isolating the analyte is the precipitation reaction, which requires the formation of a low-solubility, easily filterable product. Complete precipitation of the analyte may require the addition of a “carrier” species that “co-precipitates” with the analyte under the same reaction conditions. The carrier is chosen to have no effect in subsequent…

  • precipitation titration (chemical process)

    titration: Precipitation titrations may be illustrated by the example of the determination of chloride content of a sample by titration with silver nitrate, which precipitates the chloride in the form of silver chloride. The presence of the first slight excess of silver ion (i.e., the end…

  • precipitation, chemical

    Chemical precipitation, formation of a separable solid substance from a solution, either by converting the substance into an insoluble form or by changing the composition of the solvent to diminish the solubility of the substance in it. The distinction between precipitation and crystallization

  • precipitation-hardening stainless stain (metallurgy)

    stainless steel: Precipitation-hardening stainless steel is characterized by its strength, which stems from the addition of aluminum, copper, and niobium to the alloy in amounts less than 0.5 percent of the alloy’s total mass. It is comparable to austenitic stainless steel with respect to its corrosion resistance,…

  • Precipitous Bluff (geographical feature, Tasmania, Australia)

    Southwest National Park: …Davey Foreshore Preserve and the Precipitous Bluff were both added to it. In 1981 it was enlarged again, with lands about the headwaters of the Davey River, and in 1990 it subsumed Mount Bowes and areas along the Upper Weld River.

  • Précis de l’art de la guerre (work by Jomini)

    Henri, baron de Jomini: …l’art de la guerre (1838; Summary of the Art of War, 1868). In 1854 he served as adviser to Tsar Nicholas on tactics during the Crimean War and in 1859 advised Emperor Napoleon III on the Italian expedition.

  • Precis de la geographie universelle (work by Malte-Brun)

    Géographie Universelle: …universal geography was Conrad Malte-Brun’s Précis de la Géographie Universelle published between 1810 and 1829. A second geography, the profusely illustrated Nouvelle Géographie Universelle by Elisée Réclus, comprised 19 volumes that were published between 1876 and 1894. Réclus’s effort was largely successful and has been called the “greatest individual writing…

  • Précis des caractères génériques des insectes disposés dans un ordre naturel (work by Latreille)

    Pierre-André Latreille: Publication of his Précis des caractères génériques des insectes disposés dans un ordre naturel (1796; “Summary of the Generic Characteristics of Insects, Arranged in a Natural Order”) marked the beginnings of modern entomology, the scientific study of insects. It also brought him the position of head of the…

  • precision (measurement)

    chemical analysis: Evaluation of results: Precision is the degree of agreement among a series of measurements of the same quantity; it is a measure of the reproducibility of results rather than their correctness. Errors may be either systematic (determinant) or random (indeterminant). Systematic errors cause the results to vary from…

  • precision approach path indicator

    airport: Navigational aids: … (VASIS) and the more modern precision approach path indicator (PAPI). Both work on the principle of guiding lights that show white when the pilot is above the proper glide slope and red when below.

  • precision farming (agriculture)

    GPS: Augmentation: …equipment with great accuracy, making precision farming a common term in agriculture.

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