Battle of Stalingrad: …a huge Soviet counteroffensive, code-named Operation Uranus (November 19–23), which had been planned by Generals Georgy Konstantinovich Zhukov, Aleksandr Mikhailovich Vasilevsky, and Nikolay Nikolayevich Voronov. It was launched in two spearheads, some 50 miles (80 km) north and south of the German salient whose tip was at Stalingrad. The counteroffensive…

alkali metal: Analytical chemistry of the alkali metals: A modification of the uranyl acetate test (the precipitation of an insoluble sodium salt with uranyl acetate) has been used as a standard test for the presence of sodium. The use of a cobaltinitrite solution permits separation of potassium from sodium by precipitation of the insoluble potassium salt. There…

uranium processing: Leaching: …to form a readily soluble uranyl carbonate complex ion, [UO2(CO3)3]4-.

mineral deposit: Roll-front deposits: …which state it forms the uranyl ion (UO2)2+. Uranyl compounds tend to be soluble in groundwater, whereas U4+ compounds are not. So long as the groundwater remains oxidizing, uranyl ions are stable and uranium can be transported by groundwater; however, when uranyl ions encounter a reducing agent such as organic…

uranium processing: Refining of yellow cake: …to yield a highly purified uranyl nitrate, UO2(NO3)2.

uranium processing: Leaching: …sulfuric acid to form a uranyl sulfate complex anion, [UO2(SO4)3]4-.

Urartian language, ancient language spoken in northeastern Anatolia and used as the official language of Urartu in the 9th–6th centuries bce. Urartu centred on the district of Lake Van but also extended over the Transcaucasian regions of modern Russia and into northwestern Iran and at times even

Haldi: …of the ancient kingdom of Urartu, which ruled the plateau around Lake Van, now eastern Turkey, from about 900 to about 600 bc. Haldi was represented as a man, with or without wings, standing on a lion; in the absence of religious texts his attributes are otherwise unknown. A Urartian…

Urartu, ancient country of southwest Asia centred in the mountainous region southeast of the Black Sea and southwest of the Caspian Sea. Today the region is divided among Armenia, eastern Turkey, and northwestern Iran. Mentioned in Assyrian sources from the early 13th century bce, Urartu enjoyed

arthritis: Crystalloid arthritis: …the deposition of needle-shaped monosodium urate crystals in the joint space (urate is a form of uric acid). Initially, gout tends to occur in one joint only, typically the big toe (podagra), though it can also occur in the knees, fingers, elbows, and wrists. Pain, frequently beginning at night, can…

Saitama: …portion of Saitama city, and Urawa, the southern part of the new city, were roughly equal in size at the time of the merger. Both had been post towns on the Nakasendō highway between Ōsaka and Edo (Tokyo) during the Tokugawa period (1603–1867), and both grew rapidly in the 20th…

Urayasu, city, northwestern Chiba ken (prefecture), east-central Honshu, Japan. Lying on a flat plain along Tokyo Bay, it is separated from the city of Tokyo to the west by the Edo River. Urayasu was a thriving fishing village during the Edo (Tokugawa) period (1603–1867) but grew only slowly until

lutetium: …Carl Auer von Welsbach and Georges Urbain, working independently. Urbain derived the name for the element from Lutetia, the ancient Roman name for Paris, to honour his native city. The name lutetium became widely accepted except in Germany, where it was commonly called cassiopeium until the 1950s. One of the…

anthropology: Urban anthropology: Urban anthropology is the study of cultural systems and identities in cities as well as the various political, social, economic, and cultural forces that shape urban forms and processes. Although anthropologists have studied the city since the 1930s, the label urban anthropology became…

blues: History and notable musicians: …adapted to the more sophisticated urban environment. Lyrics took up urban themes, and the blues ensemble developed as the solo bluesman was joined by a pianist or harmonica player and then by a rhythm section consisting of bass and drums. The electric guitar and the amplified harmonica created a driving…

urban climate, any set of climatic conditions that prevails in a large metropolitan area and that differs from the climate of its rural surroundings. Urban climates are distinguished from those of less built-up areas by differences of air temperature, humidity, wind speed and direction, and amount

museum: Museums and the environment: …the ecomuseum, such as the Ecomuseum of the Urban Community at Le Creusot–Montceau-les-Mines in France. There a bold experiment involves the community as a whole, rather than specialists, in interpreting the human and natural environment, thereby generating a better understanding among its inhabitants of the reasons for cultural, social, and…

urban contemporary music, musical genre of the 1980s and ’90s defined by recordings by rhythm-and-blues or soul artists with broad crossover appeal. Urban contemporary began as an American radio format designed to appeal to advertisers who felt that “black radio” would not reach a wide enough

James Bridges: Bridges also scored big with Urban Cowboy (1980), a formulaic but entertaining story about a young Texas construction worker (John Travolta) who lets his marriage to independent Sissy (Debra Winger) disintegrate while he struggles to be accepted in the world of Gilley’s, the famed Houston honky-tonk, with its mechanical bull…

urban culture, any of the behavioral patterns of the various types of cities and urban areas, both past and present. Research on urban cultures naturally focuses on their defining institution, the city, and the lifeways, or cultural forms, that grow up within cities. Urban scholarship has steadily

urban planning, design and regulation of the uses of space that focus on the physical form, economic functions, and social impacts of the urban environment and on the location of different activities within it. Because urban planning draws upon engineering, architectural, and social and political

urban ecosystem, any ecological system located within a city or other densely settled area or, in a broader sense, the greater ecological system that makes up an entire metropolitan area. The largest urban ecosystems are currently concentrated in Europe, India, Japan, eastern China, South America,

forestry: Urban forestry: Urban forestry, which is the management of publicly and privately owned trees in and adjacent to urban areas, has emerged as an important branch of forestry. Urban forests include many different environments such as city greenbelts; street and utility rights-of-way; forested watersheds of…

geography: Human geography as locational analysis: New subdisciplines—notably urban geography—came rapidly to the fore, as systematic specialisms displaced regional courses from the core of many curricula. Other parts of the discipline—economic, social, political, and historical—were influenced by the theoretical and quantitative revolutions. What became known as a “new” human geography was created, initially…

geology: Other areas of application: of engineering, environmental, and urban geology are broadly concerned with applying the findings of geologic studies to construction engineering and to problems of land use. The location of a bridge, for example, involves geologic considerations in selecting sites for the supporting piers. The strength of geologic materials such as…

urban sprawl: Smart growth communities: …employing smart growth principles are urban growth boundaries. Urban growth boundaries involve the drawing of mapped lines that separate areas designated for urban expansion from open space and, beyond that, agriculture. The boundary is typically kept in place for a period of 20 years to encourage development within the city…

guerrilla warfare: The Cold War period: …was the media-heightened impact of urban guerrilla warfare, and such its potential danger to civilized society, that some observers believed “urban terrorism” should be classified as a new genre of warfare. But terrorist tactics, urban or rural, even the most extreme, have always been integral to guerrilla and counterguerrilla warfare—indeed…

Saint Urban I ; feast day May 25) was the pope from 222 to 230. Succeeding that of St. Calixtus I, his pontificate occurred within the reign of the Roman emperor Severus Alexander, a time of peace for the church. His baptism of St. Cecilia’s husband, St. Valerian, is fictitious. He was buried in

Urban II was the head of the Roman Catholic Church (1088–99) who developed ecclesiastical reforms begun by Pope Gregory VII, launched the Crusade movement, and strengthened the papacy as a political entity. Odo was born of noble parents about 1035 in the Champagne region of France. After studies in

Urban III was the pope from 1185 to 1187. Of noble birth, he was made cardinal and archbishop of Milan in 1182 by Pope Lucius III, whom he succeeded on Nov. 25, 1185, and from whom he inherited an imperial diplomatic crisis that harassed his entire pontificate. On Jan. 27, 1186, Henry VI, son of

Native American: Reorganization: …of Indian Affairs instituted the Urban Indian Relocation Program. Initiated within the bureau in 1948 and supported by Congress from the 1950s on, the relocation program was designed to transform the predominantly rural native population into an assimilated urban workforce. The bureau established offices in a variety of destination cities,…

Yvonne Farrell and Shelley McNamara: …Spatial Dynamics Lab (formerly the Urban Institute of Ireland; 2002), Dublin. Reflecting the materials of neighbouring buildings on the University College Dublin campus, the Spatial Dynamics Lab features unique applications of brick, concrete, and wood. Brick “fins” on one facade, for example, act as shades for a row of windows…

Urban IV was the pope from 1261 to 1264. Urban was of humble origin. He was first a priest at Lyon and then professor of canon law at Paris before being elevated to the bishopric of Verdun in 1253. Two years later he was made patriarch of Jerusalem by Pope Alexander IV. Despite not having been made

National Urban League, American service agency founded for the purpose of eliminating racial segregation and discrimination and helping African Americans and other minorities to participate in all phases of American life. By the late 20th century more than 110 local affiliated groups were active

Jared Leto: Early life and career: …up with the slasher movie Urban Legend (1998). He also appeared in Terrence Malick’s star-packed war drama The Thin Red Line (1998). Leto played club regular Angel Face in the cult classic Fight Club (1999) and had major roles in Girl, Interrupted (1999) and American Psycho (2000).

urban legend, in folklore, a story about an unusual or humorous event that many people believe to be true but that is not true. Urban legends typically combine secondhand narratives, such as those heard from “a friend of a friend,” with contemporary settings and familiar everyday objects, such as

Chris Burden: …from Erector set parts, and Urban Light (2008), a permanent—and now iconic—installation of some 200 restored antique lampposts outside the Los Angeles County Museum of Art. In 2013 he was the subject of a large-scale retrospective, “Chris Burden: Extreme Measures,” organized by the New Museum, in New York. He received…

sociology: Ecological patterning: …Chicago School’s urban research involved mapping locations. These included locations of land values, specific populations (racial, ethnic, or occupational), ethnic succession in neighbourhoods, residences of persons who committed certain crimes, or zones with a high incidence of divorce and desertion. Data-collection methods included participant observation, life histories, case studies, historical…

Spain: Moderates, progressives, and the generals: Their instrument was the Urban Militia. General Espartero used his military faction and his supporters among the younger progresista politicians and their artisan followers in the great cities to oust María Cristina and establish himself as regent (1841–43). Espartero proved a disappointment to the radical progresistas, who now allied…

urban contemporary music, musical genre of the 1980s and ’90s defined by recordings by rhythm-and-blues or soul artists with broad crossover appeal. Urban contemporary began as an American radio format designed to appeal to advertisers who felt that “black radio” would not reach a wide enough

urban legend, in folklore, a story about an unusual or humorous event that many people believe to be true but that is not true. Urban legends typically combine secondhand narratives, such as those heard from “a friend of a friend,” with contemporary settings and familiar everyday objects, such as

urban planning, design and regulation of the uses of space that focus on the physical form, economic functions, and social impacts of the urban environment and on the location of different activities within it. Because urban planning draws upon engineering, architectural, and social and political

urban culture: Definitions of the city and urban cultures: …City, 1973), Manuel Castells (The Urban Question, 1977), and other scholars influenced by Marxism caused a major shift in the conception of urban cultural roles. Although they mainly worked on cities in advanced capitalist cultures, their approach had wide relevance. Rather than looking outward from the city to the…

African American literature: The advent of urban realism: Despite the enormous outpouring of creativity during the 1920s, the vogue of Black writing, Black art, and Black culture waned markedly in the early 1930s as the Great Depression took hold in the United States. African American pundits in the 1930s and ’40s…

Cuba: Housing: The Urban Reform Law of 1960 prohibited landlords from renting urban real estate, and families soon began buying homes by paying the current rental sum for between 5 and 20 years. Many families have acquired titles to houses and apartments in this fashion, and the rest…

urban renewal, comprehensive scheme to redress a complex of urban problems, including unsanitary, deficient, or obsolete housing; inadequate transportation, sanitation, and other services and facilities; haphazard land use; traffic congestion; and the sociological correlates of urban decay, such as

urban revolution, in anthropology and archaeology, the processes by which agricultural village societies developed into socially, economically, and politically complex urban societies. The term urban revolution was introduced by the archaeologist V. Gordon Childe. Childe identified 10 formal

Toyo Ito: …he established his own practice, Urban Robot (URBOT), in Tokyo, initially focusing on residential and other small-scale projects. One of his most notable early designs was the White U house (1976) in Tokyo. Intended as a place of solace and retreat for Ito’s recently widowed sister, the house—built in the…

servitude: …to another) include various rights-of-way; urban servitudes (i.e., those established for convenience) include building rights in neighbouring properties, such as drainage and encroachment rights, and rights to light, support, and view.

urban culture, any of the behavioral patterns of the various types of cities and urban areas, both past and present. Research on urban cultures naturally focuses on their defining institution, the city, and the lifeways, or cultural forms, that grow up within cities. Urban scholarship has steadily

urban sprawl, the rapid expansion of the geographic extent of cities and towns, often characterized by low-density residential housing, single-use zoning, and increased reliance on the private automobile for transportation. Urban sprawl is caused in part by the need to accommodate a rising urban

Our Future Eco-Cities: Beyond Automobile Dependence: …of the biggest problems is transport. Motor vehicles fill the streets of every city from Los Angeles to Lagos, from Beijing to Berlin, causing chronic congestion, chaotic parking, air pollution, noise, crippled bus systems, traffic deaths, and despoiled public environments, which make walking and cycling, the most sustainable modes, extremely…

tunnels and underground excavations: Settlement damage and lost ground: …rights-of-way, the dominant concern in urban tunneling is the need to avoid intolerable settlement damage to adjoining buildings. While this is rarely a problem in the case of modern skyscrapers, which usually have foundations extending to rock and deep basements often extending below the tunnel, it can be a decisive…

Blessed Urban V ; beatified March 10, 1870) ; feast day December 19) was the pope from 1362 to 1370. Of noble birth, he joined the Benedictines, later teaching law at Avignon. He became abbot of Saint-Germain, Auxerre, in 1352 and of Saint-Victor, Marseille, in 1361. On Sept. 28, 1362, he was

Urban VI was the pope from 1378 to 1389 whose election sparked the Western Schism (1378–1417). Archbishop first of Acerenza (1363) and then of Bari (1377), he became papal chancellor for Pope Gregory XI, whom he was elected to succeed on April 8, 1378. This election of an Italian appeased the

Urban VII was the pope from Sept. 15 to Sept. 27, 1590. Of noble birth, he held several key church offices, including papal ambassador to Spain (until 1572), cardinal priest (1583), and inquisitor general (1586). Known for his charity and piety, he was elected pope on Sept. 15, 1590, but died of

Urban VIII was the pope from 1623 to 1644. The son of an aristocratic Florentine family, Barberini filled many distinguished church appointments. He served as papal legate in France (1601) and was simultaneously appointed (1604) archbishop of Nazareth and nuncio to Paris. Pope Paul V made him

yellow fever: The course of the disease: …the yellow fever virus: (1) urban, or classical, yellow fever, in which transmission is from person to person via the “domestic” (i.e., urban-dwelling) Aedes aegypti mosquito; (2) jungle, or sylvatic, yellow fever, in which transmission is from a mammalian host (usually a monkey) to humans via any one of a…

theatre: Developments in the United States: …was represented by the Viennese Joseph Urban, who when he went to the Boston Opera before World War I took with him an entire atelier of draftsmen and scenic artists. Urban moved into musical comedy and eliminated the acreage of painted vistas and box sets that had been manufactured by…

Keith Urban is a New Zealand-born Australian singer, songwriter, and guitarist who earned recognition both inside and outside the country music sphere for his pop-rock influences and honest lyrics. Urban moved with his family from New Zealand to Queensland, Australia, when he was two years old.

Keith Urban is a New Zealand-born Australian singer, songwriter, and guitarist who earned recognition both inside and outside the country music sphere for his pop-rock influences and honest lyrics. Urban moved with his family from New Zealand to Queensland, Australia, when he was two years old.

religious experience: Study and evaluation: Hocking, and Wilbur M. Urban represented an idealist tradition in interpreting religion, stressing the concepts of purpose, value, and meaning as essential for understanding the nature of God. Naturalist philosophers, of whom John Dewey was typical, have focused on the “religious” as a quality of experience and…

Urbana, city, seat (1833) of Champaign county, east-central Illinois, U.S. Urbana is contiguous with Champaign (west), about 135 miles (220 km) southwest of Chicago. The two cities are often called Champaign-Urbana. The area was first settled in 1822, and in 1833 the city was founded as the county

Urbana, city, Champaign county, west-central Ohio, U.S., in a stock-raising and farming area, 40 miles (64 km) northeast of Dayton. Laid out in 1805 by Col. William Ward of Virginia, it became the county seat in the same year and grew after a training camp was established there by Gen. William Hull

urbanization, the process by which large numbers of people become permanently concentrated in relatively small areas, forming cities. The definition of what constitutes a city changes from time to time and place to place, but it is most usual to explain the term as a matter of demographics. The

Poor Clare: …came to be called the Urbanist Poor Clares or officially the Order of St. Clare (O.S.C.), whereas those communities who continued to observe the stricter rule of St. Clare (as revised in 1253) became known as the Primitives.

urbanization, the process by which large numbers of people become permanently concentrated in relatively small areas, forming cities. The definition of what constitutes a city changes from time to time and place to place, but it is most usual to explain the term as a matter of demographics. The

Hungary: Charles III and Maria Theresa: …introduced some improvements (notably the Urbarial Patent in 1767, which attempted to standardize peasant holdings and obligations), followed their masters in aspiring to nothing more than as much material comfort as could be obtained with a minimum of effort. The national language itself was becoming little more than a peasant…

Karl Gutzkow: Gutzkow also wrote Das Urbild des Tartüffe (1844; “The Model for Tartuffe”), a clever and topical satirical comedy; and Uriel Acosta (1846), which uses the story of the martyrdom of that forerunner of Spinoza to make a plea for religious freedom. By this time he had published the…

Erbil, city, capital of Erbil muḥāfaẓah (governorate), northern Iraq. The city is also the capital of the Kurdistan Regional Government (KRG) in Iraq and is among the largest cities in that country. It is one of the most ancient cities in the world, dating back at least to 2300 bce. Erbil has long

Lope de Vega: Life: …incredible court scandal, Vega abducted Isabel de Urbina (the “Belisa” of many of his poems), the beautiful 16-year-old sister of Philip II’s earl marshal. They were forced to marry, and the new husband immediately departed with the Spanish Armada against England. On his return, he passed the remainder of his…

Urbino, town, Marche (the Marches) regione (region), central Italy. Founded by the Umbrians, an ancient people of Italy, it was subsequently occupied by the Etruscans, Celts, and Gauls and, in the 3rd century bce, by the Romans. It eventually fell under church rule in the 9th century but was ceded

Urbino majolica, Italian tin-glazed earthenware made in the city of Urbino, which from about 1520 dominated the market. Early wares, mostly dishes, are decorated with narrative scenes that typically cover the entire surface. The narrative scenes are taken from the Bible, from Classical mythology,

Urbino majolica, Italian tin-glazed earthenware made in the city of Urbino, which from about 1520 dominated the market. Early wares, mostly dishes, are decorated with narrative scenes that typically cover the entire surface. The narrative scenes are taken from the Bible, from Classical mythology,

Lorenzo di Piero de’ Medici, duca di Urbino was the ruler of Florence from 1513 to 1519, to whom Niccolò Machiavelli addressed his treatise The Prince, counselling him to accomplish the unity of Italy by arming the whole nation and expelling its foreign invaders. Lorenzo’s father, Piero, son of

Urbino, town, Marche (the Marches) regione (region), central Italy. Founded by the Umbrians, an ancient people of Italy, it was subsequently occupied by the Etruscans, Celts, and Gauls and, in the 3rd century bce, by the Romans. It eventually fell under church rule in the 9th century but was ceded

Toyo Ito: …he established his own practice, Urban Robot (URBOT), in Tokyo, initially focusing on residential and other small-scale projects. One of his most notable early designs was the White U house (1976) in Tokyo. Intended as a place of solace and retreat for Ito’s recently widowed sister, the house—built in the…

Leipzig, city, western Saxony Land (state), east-central Germany. It lies just above the junction of the Pleisse, Parthe, and Weisse Elster rivers, about 115 miles (185 km) southwest of Berlin. Leipzig is situated in the fertile, low-lying Leipzig Basin, which has extensive deposits of lignite

Orvieto, town, Umbria regione, central Italy. The town is situated atop an isolated rock 640 feet (195 m) above the junction of the Paglia and Chiana rivers. An Etruscan and later a Roman city (in late Roman times it was called Urbs Vetus, from which its Italian name is derived), Orvieto was the

Sir Thomas Urquhart was a Scottish author best known for his translation of the works of François Rabelais, one of the most original and vivid translations from any foreign language into English. Urquhart studied at King’s College, Aberdeen, and fought against the Covenanters at Turriff (1639). He

urchin, any of several marine invertebrates of the class Echinoidea (phylum Echinodermata), including the cake urchin, heart urchin, and sea urchin

Urci, ancient settlement in southeastern Roman Hispania mentioned by Pomponius Mela, Pliny the Elder, and Claudius Ptolemy. The writings of these historians indicate that the city was located in the hinterland of what is now Villaricos, Spain, in the lower basin of the Almanzora

Norn: Some sources name them Urd, Verdandi, and Skuld, perhaps meaning “past,” “present,” and “future.” They were depicted as living by Yggdrasill, the world tree, under Urd’s well and were linked with both good and evil. Being frequently attendant at births, they were sometimes associated with midwifery. The name Norn…

Andrés de Urdaneta was a navigator whose discovery of a favourable west-to-east route across the Pacific made colonization of the Philippines and transpacific commerce possible. As a young man, Urdaneta spent eight adventurous years in the Spice Islands (Moluccas) and then, in 1553, entered the

Norn: …Yggdrasill, the world tree, under Urd’s well and were linked with both good and evil. Being frequently attendant at births, they were sometimes associated with midwifery. The name Norn appears only in Scandinavian sources, but the cult of Nornlike beings occurs in several European folklores. In Norse literature the Norns…

Urdu language, member of the Indo-Aryan group within the Indo-European family of languages. Urdu is spoken as a first language by nearly 70 million people and as a second language by more than 100 million people, predominantly in Pakistan and India. It is the official state language of Pakistan and

Urdu literature, writings in the Urdu language of the Muslims of Pakistan and northern India. It is written in the Perso-Arabic script, and, with a few major exceptions, the literature is the work of Muslim writers who take their themes from the life of the Indian subcontinent. Poetry written in

Jordan, Arab country of Southwest Asia, in the rocky desert of the northern Arabian Peninsula. Jordan is a young state that occupies an ancient land, one that bears the traces of many civilizations. Separated from ancient Palestine by the Jordan River, the region played a prominent role in biblical

Jordan River, river of southwestern Asia, in the Middle East region. It lies in a structural depression and has the lowest elevation of any river in the world. The river rises on the slopes of Mount Hermon, on the border between Syria and Lebanon, and flows southward through northern Israel to the

Jordan, Arab country of Southwest Asia, in the rocky desert of the northern Arabian Peninsula. Jordan is a young state that occupies an ancient land, one that bears the traces of many civilizations. Separated from ancient Palestine by the Jordan River, the region played a prominent role in biblical

Irvin Kershner: From B-24s to Laura Mars: …married couple Robert Shaw and Mary Ure as husband and wife; and A Fine Madness (1966) featured Sean Connery as an irreverent poet whose outbursts of violence earn him a lobotomy. In 1967 Kershner directed The Flim-Flam Man, a profile of a Southern con man played by George C. Scott.

Bob Geldof: …Christmas?” with his writing partner Midge Ure, front man of the band Ultravox. Geldof then recruited some of the biggest names in the British pop scene—Simon Le Bon of Duran Duran, George Michael, Sting, Bono, Phil Collins, Boy George, and others—to contribute to the recording, which was marketed under the…

Ouvéa Island, northernmost of the Loyalty Islands, an island group within the French overseas country of New Caledonia, southwestern Pacific Ocean. Ouvéa is a crescent-shaped atoll, 30 miles (50 km) long and 4.5 miles (7 km) wide. The most fertile of the group, it is wooded and produces copra for

urea, the diamide of carbonic acid. Its formula is H2NCONH2. Urea has important uses as a fertilizer and feed supplement, as well as a starting material for the manufacture of plastics and drugs. It is a colourless, crystalline substance that melts at 132.7° C (271° F) and decomposes before

Sir Hans Adolf Krebs: …reactions (now known as the urea cycle) by which ammonia is converted to urea in mammalian tissue; the urea, far less toxic than ammonia, is subsequently excreted in the urine of most mammals. This cycle also serves as a major source of the amino acid arginine.

chondrichthyan: Salt and water balance: …blood, an ability termed the urea retention habitus. The concentration within the body thus exceeds that of the surrounding seawater, and water moves into the body with no expenditure of energy. When any of these fishes moves into fresh water, as many do, the urine flow to the outside increases;…

urea-formaldehyde resin, any of a class of synthetic resins obtained by chemical combination of urea (a solid crystal obtained from ammonia) and formaldehyde (a highly reactive gas obtained from methane). Urea-formaldehyde resins are used mostly as adhesives for the bonding of plywood,

infectious disease: Mycoplasmas and ureaplasmas: Mycoplasmas and ureaplasmas, which range in size from 150 to 850 nanometers, are among the smallest known free-living microorganisms. They are ubiquitous in nature and capable of causing widespread disease, but the illnesses they produce in humans are generally milder than those caused by…

urease, an enzyme that catalyzes the hydrolysis of urea, forming ammonia and carbon dioxide. Found in large quantities in jack beans, soybeans, and other plant seeds, it also occurs in some animal tissues and intestinal microorganisms. Urease is significant in the history of enzymology as the first

meteorite: Achondrites: …class of asteroid-derived achondrites, the ureilites, are carbon-bearing. They consist of a silicate rock, made primarily of the minerals olivine and pyroxene, that has dark veins running through it. The veins, which constitute as much as 10 percent of the meteorites, are composed of carbon (graphite and some diamond), nickel-iron…