(from the article "titration") ...will signal the end point at, or very close to, the equivalence point. Such titrations, classified according to the nature of the chemical reaction occurring between the sample and titrant, include: acid-base titrations, precipitation titrations, complex-formation titrations, and oxidation-reduction (redox) titrations. In acid-base titration (i.e., the titration of an acid ...
(from the article "Mars") ...encompass all of the terrain within 30° of the pole except for the layered terrains immediately around the pole. Three broad lobes extend to lower latitudes. These include Chryse Planitia and Acidalia Planitia (centred on 30° W longitude), Amazonis Planitia (160° W), and Utopia Planitia (250° W). The only significant ...
(from the article "The Environment") ...reef tourism or fishing. Seawater is naturally alkaline, with an average pH of 8.2. (On the pH scale, values above 7 are alkaline, values below 7 are acidic, and lower values correspond to greater acidity.) The study suggested that by the year 2100 anticipated increases in atmospheric carbon dioxide would ...
(from the article "acid-base reaction") ...Since readily accessible values of Ka are always much less than unity, it is often convenient to introduce a quantity pKa, sometimes called the acidity exponent, and defined by the relation pKa = −log10Ka. Values of pKa are generally of a more convenient...
(from the article "acid-base reaction") ...H9O4+), and a decrease in water content increases the proton-donating power of the solution. The acidity of these concentrated solutions is commonly measured by the acidity function, H0, a quantity measured by the effect of the solvent on a basic indicator I. It is defined by H0 + pK
abnormally high level of acidity, or low level of alkalinity, in the body fluids, including the blood. There are two primary types of acidosis: respiratory acidosis and metabolic acidosis. Respiratory acidosis results from inadequate excretion of carbon dioxide from the lungs. This may be caused by severe acute or chronic ... [5 Related Articles]
(from the article "nitrogen group element") Two principal techniques for converting phosphate rock to usable materials are practiced. One involves acidulation of the crushed rock-with either sulfuric or phosphoric acids-to form crude calcium hydrogen phosphates that, being water-soluble, are valuable additions to fertilizer. The other method is the reduction of the phosphate with carbon in an ...
(from the article "Cassandre") ...cofounded the advertising agency Alliance Graphique and soon turned his attention to experimental typography. In 1929 he designed Bifur, a new typeface. Later, he designed two other typefaces, Acier Noir (1935) and Piegnot (1937). In 1939 he abandoned poster art and henceforth devoted himself to designing stage sets and to ...
(from the article "pottery") ...Sevres, and the work of Meissen for the next 50 years is much less important than formerly. The transitional Louis XVI style of c. 1763-74 is typified by the figure modelling of Michel Victor Acier, who came to the factory to share the position of Modellmeister with Kandler in 1764. ...
(from the article "pharmaceutical industry") ...to allow him use of a laboratory to search for the active substance from the pancreas. Banting guessed correctly that the islet cells secreted insulin, which was destroyed by enzymes from the acinar cells. By this time Banting had enlisted the support of Charles Best, a fourth-year medical student. Together ...
(from the article "feline") 1 Asian species.1 almost exclusively African...cheetahStatus and taxonomy...in the evolutionary history of the cat family (Felidae). The cheetah was therefore granted unique taxonomic status, and since the early 1900s it has been ...
(from the article "respiratory disease") ...trachea-there are about 650,000 terminal bronchioles. The cross-sectional area of the bronchial tree increases with increasing subdivision. The end of each terminal bronchiole opens into an acinus, so called because the structure resembles a cluster of grapes, and from this point onward the gas-exchanging portion of the lung is reached. ...
(from the article "sturgeon") A. guldenstadtii is one of the most valuable species inhabiting the rivers of Russia and occurs eastward to Lake Baikal. It is about the same size as the common sturgeon and is found particularly in the rivers feeding the Black and Caspian seas. A smaller species, the sterlet (A. ruthenus), ...
(from the article "sturgeon") The common Old World sturgeon (Acipenser sturio) occurs from Scandinavia to the Mediterranean. A very similar, closely related form, considered a separate species (A. oxyrhynchus) by some authorities, occurs along the east coast of North America. The length of these fishes is generally to about 3 m; weight is to ...
(from the article "sturgeon") ...in the rivers feeding the Black and Caspian seas. A smaller species, the sterlet (A. ruthenus), inhabits the Black and Caspian seas and is a valuable food fish about 0.9 m long. A. stellatus occurs in the rivers of the Black and Caspian seas and of the Sea of Azov. ...
(from the article "chondrostean") The origin of the order Acipenseriformes (which includes the sturgeon) is not known, although they were clearly derived from some palaeonisciform groups. Fossils that are without doubt related to the sturgeons and paddlefishes are no older than the Upper Cretaceous (about 65,000,000 to 100,000,000 years ago). Earlier, the history of ...
town and episcopal see, eastern Sicily, Italy, on terraces above the Ionian Sea at the foot of Mount Etna, 7 miles (11 km) northeast of Catania. Known as Aquilia by the Romans, the town was called Reale by Philip IV of Spain in 1642. The first part of its name ...
in the Greek mythology of Ovid, the son of Faunus (Pan) and the nymph Symaethis. He was a beautiful shepherd of Sicily, the lover of the Nereid Galatea. His rival, Polyphemus the Cyclops, surprised them together and crushed him to pieces with a rock. His blood, gushing forth from beneath, ...
(from the article "geography") ...belief that the methods for defining regions were out of line with the scientific approaches characterizing other disciplines. Some felt that geographers had not contributed well to the war effort: Edward A. Ackerman, a professor of geography at the University of Chicago from 1948 to 1955 (and later head of ...
(from the article "truck") Steering of trucks, with their relatively heavy loads, was a problem until power steering came into use in the early 1950s. Steering is always by the Ackermann system, which provides a kingpin for each front wheel. Maximum cramp angle of the front wheels is about 35 degrees. The minimum turning ...
(from the article "logic, history of") ...of the semantic and syntactic notions necessary to characterize consistency precisely. The first clear proof of the consistency of the first-order predicate logic is found in the work of Hilbert and Wilhelm Ackermann from 1928. Here the problem was not only the precise awareness of consistency as a property of ...
(from the article "1986: Other Winners") ...Screenplay: Woody Allen for Hannah and Her SistersAdapted Screenplay: Ruth Prawer Jhabvala for A Room with a ViewCinematography: Chris Menges for The MissionArt Direction: Brian Ackland-Snow and Gianni Quaranta for A Room with a ViewOriginal Score: Herbie Hancock for "Round Midnight"Original Song: "Take My Breath Away" from Top...
(from the article "gastropod") ...rocky areas.Conical-shelled limpets, without slits or holes, found in rocky shallow waters (Acmaeidae and Patellidae).Small to large spiral shells in shallow to deep ocean waters, often brightly coloured,...
(from the article "baseball") ...being raised. Black players were in the minor leagues for the next few years, but their numbers declined steadily. The last black players in the recognized minor leagues during 19th century were the Acme Colored Giants, who represented Celoron, New York, in the Iron and Oil Leagues in 1898.
member of a small group of early-20th-century Russian poets reacting against the vagueness and affectations of Symbolism. It was formed by the poets Sergey Gorodetsky and Nikolay S. Gumilyov. They reasserted the poet as craftsman and used language freshly and with intensity. Centred in St. Petersburg, the Acmeists were associated ... [5 Related Articles]
(from the article "aegirine") ...occurs in crystalline schists. Aegirine forms a continuous chemical series with aegirine-augite, in which calcium replaces sodium, and magnesium and aluminum replace iron. In this series, the name acmite is given to crystals with the composition NaFeSi2O6 as well as to the reddish brown or greenish black pointed crystals approximating ...
any inflammatory disease of the sebaceous, or oil, glands of the skin. There are some 50 different types of acne. In common usage, the term acne is frequently used alone to designate acne vulgaris, or common acne, probably the most prevalent of all chronic skin disorders. [3 Related Articles]
(from the article "childhood disease and disorder") Acne vulgaris (common acne) is a prevalent skin condition that has its onset during adolescence. At puberty, androgenic stimulation of the skin's sebaceous (oil) glands (which empty into the canals of the hair follicles) causes increased production of the fatty substance sebum. In susceptible individuals, there is oversecretion of sebum. ...
(from the article "Literature") ...trance. He would stare straight ahead and utter a low hum and beat time with his hands. People would come up to him and ask him if he was all right.") The New Yorker dance critic Joan Acocella, who added literature to the subjects she expatiated on, published a number ...
(from the article "gastropod") ...shell; operculum present; gill and radula absent; long proboscis with stylet; ectoparasitic; in warm oceanic areas; generally minute.Three families with visceral mass longer than foot; 4 species in fresh water; a few with sexes in separate animals; size...
(from the article "flatworm") ...endocommensal (i.e., living, respectively, outside or inside another organism without harming it), or parasitic; about 3,000 species.Exclusively marine; mouth present; pharynx simple or lacking; no intestine; without protonephridia, oviducts, yolk glands, or definitely delimited gonads; about 200...
(from the article "animal") Flatworms (phyla Platyhelminthes, Nemertea, and Mesozoa) lack a coelom, although nemerteans have a fluid-filled cavity at their anterior, or head, end, which is used to eject the proboscis rapidly. The lack of a fluid-filled cavity adjacent to the muscles reduces the extent to which the muscles can contract and the ...
monks at a series of 5th- to 6th-century Byzantine monasteries who were noted for their choral recitation of the divine office in constant and never interrupted relays. Their first monastery, at Constantinople, was founded in about 400 by St. Alexander Akimetes, who, after long study of the Bible, put into ... [1 Related Articles]
(from the article "Texcoco") city built in the present-day Valley of Mexico by the Acolhuas, a pre-Columbian people of the Nahuatl-speaking group of tribes, which gained mastery of the valley after the collapse of the Toltec hegemony in the mid-12th century AD. The rulers of Texcoco were the first among Nahuatl tribal leaders to ...
(from Greek akolouthos, "server," "companion," or "follower"), in the Roman Catholic church, a person is installed in a ministry in order to assist the deacon and priest in liturgical celebrations, especially the eucharistic liturgy. The first probable reference to the office dates from the time of Pope Victor I (189-199), ... [1 Related Articles]
(from the article "Ancestral Pueblo culture") ...boundaries of what are now the U.S. states of Arizona, New Mexico, Colorado, and Utah intersect. The descendents of the Ancestral Pueblo comprise the modern Pueblo tribes, including the Hopi, Zuni, Acoma, and Laguna. As farmers, Ancestral Pueblo peoples and their nomadic neighbours were often mutually hostile; this is the ...
Indian pueblo, Valencia county, west-central New Mexico, U.S. The pueblo lies 55 miles (89 km) west-southwest of Albuquerque and is known as the "Sky City." Its inhabitants live in terraced dwellings made of stone and adobe atop a precipitous sandstone butte 357 feet (109 metres) high. They have always engaged ...
(from the article "African spiny mouse") ...The Cairo spiny mouse has the most extensive distribution, extending from northern Africa to the Indus River; it lives near or with humans in some parts of its range. The most restricted is A. cilicicus, which is known only from a single locality in southern Turkey.
river in central Chile. It rises in the northwestern foothills of Mount Aconcagua of the Andes Mountains and flows westward from the Argentine border area to enter the Pacific Ocean north of the city of Vina del Mar after a course of 120 miles (190 km). Much of the Chilean ...
mountain in Argentina. It is commonly regarded as the highest summit in the Western Hemisphere, rising 22,834 feet (6,959 metres) above sea level. Aconcagua lies in the Southern Andes, its peak being in Mendoza province in northwestern Argentina, but its western flanks build up from the coastal lowlands of Chile, ... [7 Related Articles]
(from the article "metabolism") ...to cis-aconitate in such a way that isocitrate is formed. It is probable that all three reactants-citrate, cis-aconitate, and isocitrate-remain closely associated with aconitase, the enzyme that catalyzes the isomerization process, and that most of the cis-aconitate is not released from the enzyme surface but is immediately converted to isocitrate.
(from the article "metabolism") ...(i.e., a rearrangement of certain atoms comprising the molecule) to form isocitrate [39]. The reaction involves first the removal of the elements of water from citrate to form cis-aconitate, and then the re-addition of water to cis-aconitate in such a way that isocitrate is formed. It is probable that all ...
(from the article "aconite") any member of two genera of perennial herbs of the buttercup family (Ranunculaceae): Aconitum, consisting of summer-flowering poisonous plants (see monkshood), and Eranthis, consisting of spring-flowering ornamentals (see winter aconite).Manchurian monkshoodManchurian monkshood (Aconitum variegatum).Bernd Haynold
(from the article "monkshood") A few species are cultivated in gardens, including A. henryi, A. carmichaelii, and A. uncinatum. All species contain the powerful poison aconitine. The common monkshood, or friar's cap (A. napellus), native to mountain slopes in Europe and east to the Himalayas, has been the most important source of this drug, ...
(from the article "Tucuman") provincia (province), northwestern Argentina. The western fringe of the province is occupied by the Sierra del Aconquija, which consists of northeast-southwest-trending outlying ridges of the Andes with elevations of 8,000-18,000 feet (2,400-5,500 m). The eastern part of the province, by contrast, is flat, alluvial, and agriculturally fertile....
