(from the article "heterocyclic compound") Azetidine, oxetane, and thietane-four-membered rings containing, respectively, one nitrogen, oxygen, or sulfur atom-are prepared by nucleophilic displacement reactions similar to those used to prepare the corresponding three-membered rings.
(from the article "oxeye") in Britain, any of certain small sandpipers (especially the dunlin; q.v.) and the great tit (titmouse). See also tit.for more content related to this topic
(from the article "daisy") any of several species of garden plants belonging to the family Asteraceae (also called Compositae). The name daisy commonly denotes the oxeye daisy (Leucanthemum vulgare) and the English, or true, ...
privately funded, international organization that provides relief and development aid to impoverished or disaster-stricken communities worldwide. The original Oxfam was founded at Oxford, England, in 1942 to raise funds for ... [1 Related Articles]
(from the article "Selected Breeds of Sheep") The Oxford, a breed popular in England and in the Great Lakes region of the U.S., was produced in the mid-19th century in Oxfordshire, England, by crossing Hampshires and Cotswolds.
county, western Maine, U.S. It consists of a mountainous region bordered to the west by New Hampshire and to the north by Quebec, Canada. The Appalachian National Scenic Trail crosses ...
city, seat (1837) of Lafayette county, northern Mississippi, U.S. It is situated about 75 miles (120 km) southeast of Memphis, Tennessee. Originating as a trading post, it was incorporated in ...
city (district), administrative and historic county of Oxfordshire, England, best known for the University of Oxford, which is located within it. [3 Related Articles]
(from the article "Oxfordshire") ...strata of the Jurassic Period. The Berkshire Downs and Chiltern Hills are developed on Cretaceous chalk. The intervening clay vale stretches from northeast to southwest. It is divided into the ...
definitive historical dictionary of the English language, originally consisting of 12 volumes and a 1-volume supplement. The dictionary is a corrected and updated revision of A New English Dictionary on ... [4 Related Articles]
19th-century movement centred at the University of Oxford that sought a renewal of "catholic," or Roman Catholic, thought and practice within the Church of England in opposition to the Protestant ... [18 Related Articles]
(from the article "United Kingdom") ...again an unyielding Parliament met at Oxford (1681). By now the king had shown his determination and had frightened the local elites into believing that there was danger of another ...
(from the article "United Kingdom") ...would be to compromise. Both of these groups were loose coalitions, and neither of them dominated parliamentary politics. Until his death in 1643, Pym steered a course between them, supporting ...
(from the article "savings and loan association") The Oxford Provident Building Association of Philadelphia, which began operating in 1831 with 40 members, was the first savings and loan association in the United States. By 1890 they had ...
(from the article "biblical literature") ...50 years (c. 1120) of the Conquest, Eadwine's Psalterium triplex, which contained the Latin version accompanied by Anglo-Norman and Anglo-Saxon renderings, appeared. The contemporary Oxford Psalter achieved such influence that ...
(from the article "publishing, history of") ...result of direct subsidies, coupled with their assured, if limited, market, enables many to reach high standards of production and commercial viability. Some of the older establishments, such as the ...
English lyric poet and patron of an acting company, Oxford's Men, who became, in the 20th century, the strongest candidate proposed (next to William Shakespeare himself) for the authorship of ... [2 Related Articles]
English soldier and royal official, a Lancastrian leader in the Wars of the Roses. He helped to restore the deposed King Henry VI (1470) and later (1485) to secure the ... [1 Related Articles]
(1258), in English history, a plan of reform accepted by Henry III, in return for the promise of financial aid from his barons. It can be regarded as England's first ... [5 Related Articles]
favourite of King Richard II of England (ruled 1377-99) during that monarch's minority. He led the group of courtiers who unsuccessfully supported Richard's efforts in 1385-87 to wrest control of ... [1 Related Articles]
British statesman who headed the Tory ministry from 1710 to 1714. Although by birth and education he was a Whig and a Dissenter, he gradually over the years changed his ... [10 Related Articles]
English autonomous institution of higher learning at Oxford, Oxfordshire, England, one of the world's great universities. It lies along the Upper River Thames (called by Oxonians the Isis), 50 miles ... [18 Related Articles]
lowest of the three divisions of the Upper Jurassic Series, representing all rocks formed worldwide during the Oxfordian Age, which occurred between 161.2 million and 155.7 million years ago during ...
administrative and historic county of south-central England, bounded on the north by Warwickshire and Northamptonshire, on the west by Gloucestershire, on the south by Berkshire, and on the east by ...
(from the article "dairy product") ...chemical changes in organic substances. Enzyme action in milk systems is extremely important for its effect on the flavour and body of different milk products. Lipases (fat-splitting enzymes), oxidases, proteases ...
(from the article "alcohol") Alcohols may be oxidized to give ketones, aldehydes, and carboxylic acids. These functional groups are useful for further reactions; for example, ketones and aldehydes can be used in subsequent Grignard ...
(from the article "environmental works") Oxidation ponds, also called lagoons or stabilization ponds, are large, shallow ponds designed to treat wastewater through the interaction of sunlight, bacteria, and algae. Algae grow using energy from the ...
(from the article "electromotive series") ...litre is maintained at 25° C (77° F) in equilibrium with hydrogen in its reduced form (hydrogen gas, H2) at a pressure of one atmosphere. The reversible oxidation-reduction half reaction ...
any chemical reaction in which the oxidation number of a participating chemical species changes. The term covers a large and diverse body of processes. Many oxidation-reduction reactions are as common ... [17 Related Articles]
(from the article "titration") In oxidation-reduction (redox) titrations the indicator action is analogous to the other types of visual colour titrations. In the immediate vicinity of the end point, the indicator undergoes oxidation or ...
(from the article "metabolism") In oxidative phosphorylation the oxidation of catabolic intermediates by molecular oxygen occurs via a highly ordered series of substances that act as hydrogen and electron carriers. They constitute the electron ...
any of a large and important class of chemical compounds in which oxygen is combined with another element. With the exception of the lighter inert gases (helium [He], neon [Ne], ... [18 Related Articles]
(from the article "Characteristics of oxide glasses") Electronic conduction of charge is important in only two families of glasses: oxide glasses containing large amounts of transition-metal ions and chalcogenides. In metallic solids there are a large number ...
any naturally occurring inorganic compound with a structure based on close-packed oxygen atoms in which smaller, positively charged metal or other ions occur in ... [4 Related Articles]
(from the article "aging") The metabolic activities of organisms produce highly reactive chemicals, including strong oxidizing agents. The internal structure of the cell, however, minimizes the harmful effects of such agents; the critical reactions ...
any member of a class of enzymes, commonly known as dehydrogenases or oxidases, that catalyze the removal of hydrogen atoms and electrons from the compounds on which they act. Substances ... [2 Related Articles]
any of a class of nitrogen-containing organic compounds usually prepared from hydroxylamine and an aldehyde, a ketone, or a quinone. Oximes have the structure X\Y/C&doublehorzbond; N&singlehorzbond;OH, in which X and ...
one of the 12 soil orders in the U.S. Soil Taxonomy. Oxisols form principally in humid tropical zones under rainforest, scrub and thorn forest, or savanna vegetation on flat to ... [2 Related Articles]
surveyor-general and explorer who played an important part in the exploration of eastern Australia and also helped open up Van Diemen's Land (later Tasmania). [4 Related Articles]
city, Ventura county, southwestern California, U.S. It lies near the Pacific coast, between Los Angeles and Santa Barbara. Originally inhabited by Chumash Indians, the city was founded in 1898 near ...
(from the article "halogen element") ...exhibits the oxidation states of −1 (F− ion) and +1 (hypofluorous acid). The principal oxidation states of chlorine, bromine, and iodine are −1, +1, +3, +5, and +7. The oxyacids ...
(from the article "organosulfur compound") ...between peroxides (R&singlehorzbond;OO&singlehorzbond;R), disulfides (R&singlehorzbond;SS&singlehorzbond;R), and diselenides (R&singlehorzbond;SeSe&singlehorzbond;R), and between oxonium (R3O+), sulfonium (R3S+), and selenonium salts (R3Se+), where R represents a general carbon group-e.g., the methyl...
(from the article "organosulfur compound") ...typically written R2SO), sulfones (R2S(&doublehorzbond;O)2, typically written R2SO2), sulfonic acids (RSO3H), and oxosulfonium salts (R3S+&doublehorzbond;O). Analogs of the above sulfur compounds also exist for selenium. These higher-valence compounds of sulfur ...
(from the article "organosulfur compound") ...each losing a proton to give zwitterions of a special type, with the negative charge on the carbon adjacent to the positively charged sulfonium sulfur. These compounds are called sulfonium ...
either of the two species of the African genus Buphagus, of the family Sturnidae (order Passeriformes). Both species-the yellow-billed (B. africanus) and the red-billed (B. erythrorhynchus)-are brown birds 20 cm ...
(from the article "art and architecture, Iranian") ...interest. Of greater artistic importance are the many surviving examples of Achaemenian metalsmiths' work, which continued to draw extensively on the native tradition of Iranian design. The Oxus Treasure includes ...
(from the article "India") ...Banawali is an important major settlement, surrounded by massive brick defenses. One of the most surprising discoveries, far outside the central area of the Indus civilization, is Shortughai in the ...
(from the article "welding") ...welding, arc welding, and resistance welding all appeared at the end of the 19th century. The first real attempt to adopt welding processes on a wide scale was made during ...
any oxygen-containing acid. Most covalent nonmetallic oxides react with water to form acidic oxides; that is, they react with water to form oxyacids that yield hydronium ions (H3O+) in solution. ... [2 Related Articles]
(from the article "Creodonta") ...and primitive, and the skull was relatively long and low. Prominent crests present on the skull served for the attachment of well-developed chewing muscles. Two main families are distinguished: the ...
(from the article "Alexander the Great") ...a people of the Saka confederacy. It took Alexander until the autumn of 328 to crush the most determined opponent he encountered in his campaigns. Later in the same year ...
(from the article "craniosynostosis") ...grow in width, the vault becomes long, high, and narrow (scaphocephaly). If the coronal suture (side to side near the front) fuses early, the skull becomes short front to back ...
(from the article "vinyl chloride") In the other process (called oxychlorination), ethylene, hydrogen chloride, and oxygen (or air) are heated in the presence of a copper catalyst to give vinyl chloride and water.
nonmetallic chemical element of Group 16 (VIa, or the oxygen group) of the periodic table. Oxygen is a colourless, odourless, tasteless gas essential to living organisms, being taken up by ... [104 Related Articles]
(from the article "basic oxygen process") Another, though less common, oxygen steelmaking system is a bottom-blown process known as the Q-BOP (quick-quiet BOP) in North America and the OBM (from the German, Oxygen bodenblasen Maxhuette, or ...
circulation of oxygen in various forms through nature. Free in the air and dissolved in water, oxygen is second only to nitrogen in abundance among uncombined elements in the atmosphere. ... [1 Related Articles]
any of the five chemical elements making up Group 16 (VIa) of the periodic classification-namely, oxygen, sulfur, selenium, tellurium, and polonium. (See .) A relationship among the first three members ... [4 Related Articles]
(from the article "isotopic fractionation") ...factor depends on the temperature and, consequently, can be used as a means of determining the temperature of the water in which the precipitation occurs. This is the basis of ...
(from the article "Pleistocene Epoch") The isotopic record is based on the ratio of two oxygen isotopes, oxygen-16 (16O) and oxygen-18 (18O), which is determined on calcium carbonate from shells of microfossils that accumulated year ...
(from the article "Winfrey, Oprah") ...and Toni Morrison's Beloved, which appeared in 1998, also with Winfrey in a starring role. In 1998 Winfrey expanded her media entertainment empire when she cofounded Oxygen ...
(from the article "atmosphere, evolution of") ...indicates that oxygenic photosynthesis almost certainly developed earlier than 2.2 billion years ago. Whatever the precise moment of development, it marked the origin of the first so-called oxygen oasis, a ...
(from the article "food preservation") ...by the presence of oxygen and are called obligate anaerobes. Facultative anaerobes are bacteria that can grow in both the presence or absence of oxygen. In addition to oxygen concentration, ...
(from the article "Lavoisier, Antoine-Laurent") The oxygen theory of combustion resulted from a demanding and sustained campaign to construct an experimentally grounded chemical theory of combustion, respiration, and calcination. The theory that emerged was in ...
(from the article "glacier") A very useful technique for tracing past temperatures involves the measurement of oxygen isotopes-namely, the ratio of oxygen-18 to oxygen-16. Oxygen-16 is the dominant isotope, making up more than 99 ...
(from the article "Quaternary") ...been the record of stable isotopes of oxygen extracted from marine fossils, cave limestone, and ice cores. Oxygen naturally occurs in three isotopes: 16O (99.763 percent), 17O (0.0375 percent), and ...
(from the article "mass spectrometry") The Earth's crust is generally richer in oxygen-18 (18O) than is the mantle, as a result of the reaction of these upper-layer rocks with the hydrosphere and atmosphere. This fact ...
(from the article "artificial heart") ...blood circulation and oxygenation during heart surgery by diverting blood from the venous system, directing it through tubing into an artificial lung (oxygenator), and returning it to the body. The ...
(from the article "sulfur") ...With fluorine, sulfur forms sulfur fluorides, the most useful of which is sulfur hexafluoride, SF6, a gas employed as an insulator in various electrical devices. Sulfur also forms oxyhalides, in ...
(from the article "hemoglobin") ...the red blood cells (erythrocytes) of vertebrates-that transports oxygen to the tissues. Hemoglobin forms an unstable, reversible bond with oxygen; in the oxygenated state it is called oxyhemoglobin and is ...
(from the article "halide mineral") ...three broad categories of halide minerals are recognized; these categories, which are also distinguishable in their modes of occurrence, include the simple halides, the halide complexes, and the oxyhydroxy-halides.atacamite
(from the article "paradox") When a paradox is compressed into two words as in "loud silence," "lonely crowd," or "living death," it is called an oxymoron.
(from the article "meat processing") ...to the air, beef slowly turns to a bright cherry-red colour in a process called blooming. Blooming is the result of oxygen binding to the iron atom (in this state ...
(from the article "bacteria") ...green sulfur bacteria (Chlorobium); and filamentous green bacteria (Chloroflexus).Gram-negative bacteria that carry out oxygen-evolving photosynthesis. Includes the cyanobacteria and the order Prochlorales; gliding ...
(from the article "cowbane") any of several poisonous plants, including seven species of Oxypolis, in the parsley family (Apiaceae), that are especially poisonous to cattle. The plants grow in marshes and are widely distributed ...
ancient capital of the 19th Upper Egyptian nome (province), on the western edge of the Nile Valley, in al-Minya muhafazah (governorate). It is best known for the numerous papyri uncovered ...
(from the article "Oxyrhynchus") ...capital of the 19th Upper Egyptian nome (province), on the western edge of the Nile Valley, in al-Minya muhafazah (governorate). It is best known for the numerous papyri uncovered there, ...
(from the article "beekeeping") American foulbrood can be spread to healthy colonies by transferring equipment or allowing the bees to feed on honey from infected colonies. Sulfathiazole and Terramycin are widely used to control ...
hormone used clinically to help begin or to continue labour, to control bleeding following delivery, and to stimulate the secretion of breast milk. Oxytocin was first synthesized (along with the ... [9 Related Articles]
surface oceanic current flowing southwest along the Kamchatka Peninsula and the Kuril Islands. Meeting the Kuro Current Extension east of Japan, part of the cold, less saline water of the ... [3 Related Articles]
city, Tochigi ken (prefecture), Honshu, Japan, on the Omoi River. A castle town in early times, it became a post station and river port during the Tokugawa period (1603-1867). The ...
(from the article "South American forest Indian") ...fiance during the period in which he is obliged to work for his future father-in-law. The Rucuyen, a Carib tribe of French Guiana, for some time maintained in servitude a ...
river that forms the border between French Guiana and the Brazilian state of Amapa. It rises in the Tumuc-Humac Mountains and flows northeast for 311 miles (500 km) to empty ...
town, northern Gabon. It lies on a plateau at an elevation of about 3,000 feet (900 m). Oyem is an administrative and transport centre for an agricultural area. Cocoa and ...
(from the article "Literature") ...for the award were Doreen Baingana (Uganda), Jamal Mahjoub (The Sudan), Muthal Naidoo (South Africa), and Ike Okonta (Nigeria). A 20-year-old student at the University of Cambridge, Nigerian-born Helen Oyeyemi, ...
(from the article "Ewe") ...Togo who speak various dialects of Ewe, a language of the Kwa branch of the Niger-Congo family. Ewe unity is based on language and common traditions of origin: their original ...
state, western Nigeria. Oyo was reduced in size when Osun state was created out of its eastern portion in 1991. Oyo is bounded by the states of Kwara on the ...
town, Oyo state, southwestern Nigeria. Oyo lies 32 miles (51 km) north of Ibadan. In the 1830s it was declared the new seat of the alafin of Oyo (the political ...
Yoruba state north of Lagos, in present-day southwestern Nigeria, that dominated, during its apogee (1650-1750), most of the states between the Volta River in the west and the Niger River ... [8 Related Articles]
one of the three major schools of Neo-Confucianism that developed in Japan during the Tokugawa period (1603-1867). See Neo-Confucianism. [2 Related Articles]
African statesman, actor, and comic writer whose two best-known works-Une Vie de boy (1956; Houseboy) and Le Vieux Negre et la medaille (1956; The Old Man and the Medal), written ... [2 Related Articles]
African dramatist and short-story writer, one of bilingual Cameroon's few writers to achieve success both in French and in English. Oyono-Mbia attended the College Evangelique at Limbamba and then went ...
(from the article "Altaic languages") ...written Khalkha and Buryat differ from one another much more than do the closely related spoken dialects on which they are based. This condition also obtains for other Mongolian languages. ...
any member of the families Ostreidae (true oysters) or Aviculidae (pearl oysters), bivalve mollusks found in temperate and warm coastal waters of all oceans. Bivalves known as thorny oysters (Spondylus) ... [5 Related Articles]
town (urbanized township), Nassau county, southeastern New York, U.S. It extends from the north to south shores on central Long Island, and comprises more than 30 incorporated villages and unincorporated ...
(from the article "cypress pine") ...known as turpentine pine. Most of these timber trees are about 25 metres (about 80 feet) tall, but the Port Macquarie pine, also planted as an ornamental, may reach 45 ...
(from the article "Agaricales") ...rot in trees. The cap and stalk of P. squarrosa, an edible mushroom, are covered with dense, dry scales (see photograph). Among the shelf or bracket fungi growing from tree ...
(from the article "decapod") ...of some hermit crab species, for example, carry anemones or bryozoan colonies on the shell in a commensal relationship (one in which the colonies do not feed on the host ...
