internal-combustion engine: …are divided into two groups: continuous-combustion engines and intermittent-combustion engines. The continuous-combustion engine is characterized by a steady flow of fuel and oxidizer into the engine. A stable flame is maintained within the engine (e.g., jet engine). The intermittent-combustion engine is characterized by periodic ignition of air and fuel and…

materials science: Polymer-matrix composites: Continuous fibres are more efficient at resisting loads than are short ones, but it is more difficult to fabricate complex shapes from materials containing continuous fibres than from short-fibre or particle-reinforced materials. To aid in processing, most high-performance composites are strengthened with filaments that are…

cardiovascular disease: Therapy: …of obtaining a donor heart, left ventricular assist devices have been developed to increase patient survival while awaiting a transplant. These devices work by taking part of the blood from the left ventricle and mechanically pumping it into the arterial circulation. This mechanical assistance reduces the amount of work required…

separation and purification: Field separations: In continuous-flow paper electrophoresis, the sample is continuously fed (with a salt solution) at the top centre of a vertically mounted sheet of paper. As the sample flows down the paper, it is subjected to an electrical potential at right angles to the direction of flow.…

music recording: Advancements after World War II: …steady rise to popularity: the continuous-loop one-reel cartridge and the two-reel cassette. Each obviated the need for threading tape in order to play it. The cartridge first achieved consumer acceptance as an automobile accessory and was designed primarily as a playback-only format; the cassette configuration was first introduced in an…

machine tool: Numerical control (NC): Continuous-path NC systems are commonly used on machines that perform contouring operations, such as milling machines, lathes, flame-cutting machines, and drafting machines. Program preparation for continuous-path machines is more complex and usually requires the aid of a computer.

laser: Laser beam characteristics: A laser is called continuous-wave if its output is nominally constant over an interval of seconds or longer; one example is the steady red beam from a laser pointer. Pulsed lasers concentrate their output energy into brief high-power bursts. These lasers can fire single pulses or a series of…

radar: Postwar progress: …Doppler frequency is indispensable in continuous wave, MTI, and pulse Doppler radars, which must detect moving targets in the presence of large clutter echoes. The Doppler frequency shift is the basis for police radar guns. SAR and ISAR imaging radars make use of Doppler frequency to generate high-resolution images of…

space-time: …to be a flat, three-dimensional continuum—i.e., an arrangement of all possible point locations—to which Euclidean postulates would apply. To such a spatial manifold, Cartesian coordinates seemed most naturally adapted, and straight lines could be conveniently accommodated. Time was viewed independent of space—as a separate, one-dimensional continuum, completely homogeneous along its…

Mari Evans: Continuum, published in 2007 (rev. ed. 2015), contains classic poems from Evans’s previous collections as well as new work inflected by the same unique insight into African American life that defined her earlier oeuvre. In her works for young readers, Evans often touched on difficult…

John Mayer: Continuum (2006), reflecting this new approach, was another commercial success. It also earned Mayer a Grammy for best pop vocal album, and its single “Waiting on the World to Change” won for best male pop vocal performance. He continued to be a Grammy favourite in…

gas: Free-molecule gas: …ordinary gases (also known as continuum gases). A radiometer is a four-vaned mill that depends essentially on free-molecule effects. A temperature difference in the free-molecule gas causes a thermomolecular pressure difference that drives the vanes. The radiometer will stop spinning if enough air leaks into its glass envelope. (It will…

continuum hypothesis, statement of set theory that the set of real numbers (the continuum) is in a sense as small as it can be. In 1873 the German mathematician Georg Cantor proved that the continuum is uncountable—that is, the real numbers are a larger infinity than the counting numbers—a key

mechanics of solids: Stress: …1822 a basic assumption of continuum mechanics that such surface forces could be represented as a stress vector T, defined so that TdS is an element of force acting over the area dS of the surface (Figure 1). Hence, the principles of linear and angular momentum take the forms

mechanics of solids: Stress: …1822 a basic assumption of continuum mechanics that such surface forces could be represented as a stress vector T, defined so that TdS is an element of force acting over the area dS of the surface (Figure 1). Hence, the principles of linear and angular momentum take the forms

history of logic: The continuum problem and the axiom of constructibility: Another way in which Hilbert influenced research in set theory was by placing a set-theoretical problem at the head of his famous list of important unsolved problems in mathematics (1900). The problem is to prove or to disprove…

spectroscopy: Broadband-light sources: …to lower energy states and continuum radiation resulting from closely spaced lines that have been broadened by collisions with other atoms and the electrons. If the pressure of the gas in the arc lamp is sufficiently high, a large fraction of the light is emitted in the form of continuum…

history of logic: The continuum problem and the axiom of constructibility: …natural numbers, called ℵ1 (aleph-one), is equal to the cardinality of the set of all real numbers. The continuum hypothesis states that ℵ1 is the second infinite cardinal—in other words, there does not exist any cardinality strictly between ℵo and ℵ1. Despite its prominence, the problem of the continuum…

space-time, in physical science, single concept that recognizes the union of space and time, first proposed by the mathematician Hermann Minkowski in 1908 as a way to reformulate Albert Einstein’s special theory of relativity (1905). (Read Einstein’s 1926 Britannica essay on space-time.) Common

pewee, any of eight species of birds of the genus Contopus (family Tyrannidae); it is named for its call, which is monotonously repeated from an open perch. In North America a sad, clear “pee-oo-wee” announces the presence of the eastern wood pewee (C. virens), while a blurry “peeurrr” is the call

pewee: …is the call of the western wood pewee (C. sordidulus). Some authorities consider the western form to be a race of C. virens. Both forms are plain birds, about 14 cm (6 inches) long, that resemble the eastern phoebe; the two forms differ from the eastern phoebe, however, in being…

pewee: …announces the presence of the eastern wood pewee (C. virens), while a blurry “peeurrr” is the call of the western wood pewee (C. sordidulus). Some authorities consider the western form to be a race of C. virens. Both forms are plain birds, about 14 cm (6 inches) long, that resemble…

desertification: Solutions to desertification: Contour bunding (or contour bundling), which involves the placement of lines of stones along the natural rises of a landscape, and contour farming. These techniques help to capture and hold rainfall before it can become runoff. They also inhibit wind erosion by keeping the soil…

desertification: Solutions to desertification: Contour bunding (or contour bundling), which involves the placement of lines of stones along the natural rises of a landscape, and contour farming. These techniques help to capture and hold rainfall before it can become runoff. They also inhibit wind erosion by keeping the soil…

continental rise: …slope of the continental rise—namely, contour currents. Resulting sediment accumulations are called contourites. The major points of contention concerning the efficacy of contour currents are (1) whether or not they are strong enough—they flow at a speed of about 20 cm (8 inches) per second—to build the huge thicknesses of…

contour drawing, version of outline drawing, in which the artist, looking closely at the contour of an object, transfers it in one continuous line to paper without looking down to see what he is doing, except when he needs to place an internal feature such as an eye. The use of the word contour

contour farming, the practice of tilling sloped land along lines of consistent elevation in order to conserve rainwater and to reduce soil losses from surface erosion. These objectives are achieved by means of furrows, crop rows, and wheel tracks across slopes, all of which act as reservoirs to

bird: Feathers: Contour feathers form most of the surface of the bird, streamlining it for flight and often waterproofing it. The basal portion may be downy and thus act as insulation. The major contour feathers of the wing (remiges) and tail (rectrices) and their coverts function in…

line integral, in mathematics, integral of a function of several variables, defined on a line or curve C with respect to arc length s:as the maximum segment Δis of C approaches 0. The line integralsare defined analogously. Line integrals are used extensively in the theory of functions of a complex

contour line, a line on a map representing an imaginary line on the land surface, all points of which are at the same elevation above a datum plane, usually mean sea level. Imagine a land surface inundated by the sea to a depth of 100 feet (30.5 metres)—that is, the intersection of a horizontal

contour mapping, the delineation of any property in map form by constructing lines of equal values of that property from available data points. A topographic map, for example, reveals the relief of an area by means of contour lines that represent elevation values; each such line passes through

strip mining: Contour mining progresses in a narrow zone following the outcrop of a mineral seam in mountainous terrain.

auger mining: Augering is usually associated with contour strip-mining, recovering coal for a limited depth beyond the point where stripping becomes uneconomical because the seam of coal lies so far beneath the surface.

tone: In contour-tone languages at least some of the tones must be described in terms of pitch movements, such as rises and falls or more complex movements such as rise–falls. This is characteristic of many tone languages of Southeast Asia.

continental rise: Resulting sediment accumulations are called contourites. The major points of contention concerning the efficacy of contour currents are (1) whether or not they are strong enough—they flow at a speed of about 20 cm (8 inches) per second—to build the huge thicknesses of sediment that make up the rises and…

Motown: …such as the Four Tops, the Contours, and Junior Walker and the All-Stars. A number of acts that were not developed by Motown wound up enjoying hit records during a stint with the company, including the Isley Brothers and Gladys Knight and the Pips.

contredanse: …used only the country dance’s “longways” formations, in which each couple danced its way to the head of a double line (men on one side, women on the other). At the head of the line, the pair danced a duet before relinquishing the position to the next couple in line.…

contra, member of a counterrevolutionary force that sought to overthrow Nicaragua’s left-wing Sandinista government. The original contras had been National Guardsmen during the regime of Anastasio Somoza (see Somoza family). The U.S. Central Intelligence Agency played a key role in training and

skepticism: Medieval skepticism: Augustine’s Contra academicos. Augustine, before his conversion from paganism to Christianity, had found Cicero’s views attractive. But having overcome them through revelation, he characterized his subsequent philosophy as faith seeking understanding. Augustine’s account of skepticism and his answer to it provided the basis of medieval discussions.

Flavius Josephus: Josephus as historian.: …known as Contra Apionem (Against Apion, though the earlier titles Concerning the Antiquity of the Jews and Against the Greeks are more apposite). Of its two books, the first answers various anti-Semitic charges leveled at the Jews by Hellenistic writers, while the second provides an argument for the ethical…

Origen: Writings: …of Christianity against pagan attack, Contra Celsum, written (probably in 248) at Ambrose’s request, survives in its entirety in one Vatican manuscript, with fragments in the Philocalia and on papyruses. Paragraph by paragraph it answers the Alēthēs logos (“The True Doctrine” or “Discourse”) of the 2nd-century anti-Christian philosopher Celsus and…

Martinez: The completion of the Contra Costa Canal (1947) to its Martinez Reservoir terminus and the opening of the Benicia-Martinez Bridge (1962) across the strait (with construction of a new bridge begun in 1999) boosted the city’s port and industrial development (petroleum, chemicals, steel, and copper). Local attractions include the…

contredanse, genre of dance for several couples. The contredanse was an 18th-century French development of the English country dance (q.v.) and was performed into the 19th century by French, English, and German aristocrats and bourgeoisie. Contredanses at first used only the country dance’s

Ratramnus: In his Contra Graecorum opposita (“Against Greek Opposition”), Ratramnus defends the Western Church from attacks by Patriarch Photius of Constantinople during the controversy on the Filioque clause (“and from the Son”) in the Nicene Creed and pleads for unity between the Western and Eastern churches. De nativitate…

Cristóbal de Castillejo: …introduced by his contemporaries, writing Contra los que dejan los metros castellanos y siguen los italianos (c. 1540; “Against Those Who Abandon Castilian Metres for Italian Ones”) in rhymed couplets. He championed the superiority of the traditional Spanish metre. He is also known for his erotic poetry, Sermón de amores…

Mark The Hermit: …manuscript of his theological polemic Contra Nestorianos (“Against the Nestorians”), written about 430, Mark’s importance in 5th-century doctrinal controversies and his specific authorship of other writings were finally recognized. Resembling the Christological doctrine of St. Cyril of Alexandria, spokesman for 5th-century orthodoxy, Contra Nestorianos refutes the heretical Nestorian doctrine holding…

Prudentius: The two Contra Symmachum (“Books Against Symmachus”) were written in reply to that pagan senator’s requests that the altar of Victory be restored to the Senate house. The Dittochaeon (“The Double Testament”), 49 quatrains intended as captions for the murals of a basilica in Rome, is of…

countertenor, in music, adult male alto voice, either natural or falsetto. In England the word generally refers to a falsetto alto rather than a high tenor. Some writers reserve the term countertenor for a naturally produced voice, terming the falsetto voice a male alto. Derived from the

St. Jerome: Major literary works of St. Jerome: …the cult of martyrs (Contra Vigilantium, 406). The Pelagian problem—named for the heretical British monk Pelagius, who minimized the role of divine grace in salvation—was transplanted to Palestine from Rome with the personal appearance of the author of this heresy, and it called forth Jerome’s finest controversial work,

Gomarist, follower of the Dutch Calvinist theologian Franciscus Gomarus (1563–1641), who upheld the theological position known as supralapsarianism, which claimed that God is not the author of sin yet accepted the Fall of Man as an active decree of God. They also opposed toleration for Roman

Ramón José Sender: Contraataque (1938; Counter Attack in Spain) was based on his war experiences and was intended to win support for the Republicans. After the Nationalist victory in the Civil War, Sender fled to Mexico and in 1942 came to the United States, becoming a U.S. citizen in 1946.…

contraband, in the laws of war, goods that may not be shipped to a belligerent because they serve a military purpose. The laws of war relating to contraband developed in the later European Middle Ages and have undergone continual development in order to meet the needs of the major maritime powers.

Taryn Simon: …capture the photographs compiled in Contraband (2010), Simon installed herself at New York City’s John F. Kennedy International Airport for five days and photographed more than 1,000 items confiscated in customs, from bottles of date rape drugs to dead wildlife to pirated DVDs. The series was exhibited in New York…

Guns N’ Roses: Velvet Revolver’s debut album, Contraband (2004), topped the Billboard charts and received solid marks from both fans and critics. Rose returned to the studio to continue working on the next Guns N’ Roses full-length album, a process that began in 1994 with a completely different set of musicians. As…

saxhorn: …and bass in E♭ and contrabass in BB♭ (sometimes called tubas).

double bass, stringed musical instrument, the lowest-pitched member of the orchestra, sounding an octave lower than the cello. It has two basic designs—one shaped like a viol (or viola da gamba) and the other like a violin—but there are other designs, such as that of a guitar. It varies

bassoon: The first useful contrabassoon, or double bassoon, sounding an octave lower than the bassoon and much employed in large scores, was developed in Vienna and used occasionally by the classical composers. The modern contrabassoon follows Heckel’s design of approximately 1870, with the tubing doubled back four times and…

contraception, in human physiology, birth control through the deliberate prevention of conception or impregnation. The link between pregnancy and a man’s semen was dimly understood even in ancient times, so that the earliest contraceptive methods involved preventing semen from entering the woman’s

contraception, in human physiology, birth control through the deliberate prevention of conception or impregnation. The link between pregnancy and a man’s semen was dimly understood even in ancient times, so that the earliest contraceptive methods involved preventing semen from entering the woman’s

Burwell v. Hobby Lobby Stores, Inc.: Background: Eventually known as the contraceptive mandate, the regulation required companies with 50 or more employees to provide insurance coverage of the 20 contraceptive methods then approved by the Food and Drug Administration (FDA). Despite scientific consensus to the contrary, the Greens believed that four of those methods—two types of…

contract, in the simplest definition, a promise enforceable by law. The promise may be to do something or to refrain from doing something. The making of a contract requires the mutual assent of two or more persons, one of them ordinarily making an offer and another accepting. If one of the parties

belote: A contract is established when a bid is followed by three passes or by an opponent’s double. This differs from bridge in that a double establishes the last bid as the contract. The bidding side cannot then bid its way out into another suit. The only…

history of flight: From airmail to airlines in the United States: …congressional pressures and, with the Contract Air Mail Act of 1925, turned over the mail service to private contractors. The following year, the Air Commerce Act established a bureau to enforce procedures for the licensing of aircraft, engines, pilots, and other personnel. The former act stimulated design and production of…

contract bridge, card game developed in the 1920s that was the final step in the historical progression from whist to bridge whist to auction bridge to contract bridge. See

marketing: Transportation firms: There are also contract carriers, which are independent transportation firms that can be hired by companies on a long- or short-term basis. A common carrier provides services to any and all companies between predetermined points on a scheduled basis. The U.S. Postal Service is a common carrier, as…

charter party: …charter, bareboat charter, and “lump-sum” contract. The voyage charter is the most common. Under this method a ship is chartered for a one-way voyage between specific ports with a specified cargo at a negotiated rate of freight. On time charter, the charterer hires the ship for a stated period…

insurance: Major types of surety bonds: Contract construction bonds are written to guarantee the performance of contractors on building projects. Bonds are particularly important in this field because of the general practice of awarding commercial building contracts to the lowest bidder, who may promise more than can actually be performed. The…

contract labour, the labour of workers whose freedom is restricted by the terms of a contractual relation and by laws that make such arrangements permissible and enforceable. The essence of the contract labourer’s obligation is his surrender for a specified period of the freedom to quit his work

contract, in the simplest definition, a promise enforceable by law. The promise may be to do something or to refrain from doing something. The making of a contract requires the mutual assent of two or more persons, one of them ordinarily making an offer and another accepting. If one of the parties

contract: Contracts of adhesion: Familiar examples of adhesion contracts are contracts for transportation or service concluded with public carriers and utilities and contracts of large corporations with their suppliers, dealers, and customers. In such circumstances a contract becomes a kind of private legislation, in the sense that the stronger party to a…

human trafficking: Types of exploitation: Similarly, contract slavery uses false or deceptive contracts to justify or explain forced slavery. In the United States the majority of nonsex labourers are forced into domestic service, followed by agriculture, sweatshops, and restaurant and hotel work.

warranty: Social and ethical implications: …greater duties on sellers are contract theory, due-care theory, and strict-liability theory. Each essentially attaches a guarantee to the product intended to promote product safety, quality, and conformity. Although it does not compel a warranty, the due-care theory pushes manufacturers to avoid negligence and to act reasonably to protect consumers…

Contract with America, a document signed Sept. 27, 1994, on the Capitol steps in Washington, D.C., by members of the Republican minority before the Republican Party gained control of Congress in 1994. The “Contract with America” outlined legislation to be enacted by the House of Representatives

graphic novel: The first graphic novels: …graphic novel, many hold Eisner’s A Contract with God, and Other Tenement Stories (1978) to be one of the most important early examples of the graphic novel in the United States. Books like Eisner’s made clear the demand for more sophisticated comics, and the result was something of a boom…

carriage of goods: Delay and misdelivery: …will be treated as a breach of contract.

angiosperm: Root systems: Many bulbous plants have contractile adventitious roots that pull the bulb deeper into the ground as it grows. Climbing plants often grip their supports with specialized adventitious roots. Some lateral roots of mangroves become specialized as pneumatophores in saline mud flats; pneumatophores are lateral roots that grow upward (negative

contractile vacuole, regulatory organelle, usually spherical, found in freshwater protozoa and lower metazoans, such as sponges and hydras, that collects excess fluid from the protoplasm and periodically empties it into the surrounding medium. It may also excrete nitrogenous wastes. In amoebas it

contract labour, the labour of workers whose freedom is restricted by the terms of a contractual relation and by laws that make such arrangements permissible and enforceable. The essence of the contract labourer’s obligation is his surrender for a specified period of the freedom to quit his work

construction: Construction: …organization, often called a general contractor, which takes the primary responsibility for executing the building and signs a contract to do so with the building user. The cost of the contract is usually an agreed lump sum, although cost-plus-fee contracts are sometimes used on large projects for which construction begins…

paleography: Abbreviations: …into two classes, suspension and contraction. Suspension, omission of the end of a word and indication by a point or sign, was used in Roman public inscriptions—e.g., IMP.(ERATOR), CAES.(AR). Contraction, the omission of letters from the middle of a word and replacement by a sign or some other device, was…

muscle: Whole muscle: Striated muscle contracts to move limbs and maintain posture. Both ends of most striated muscles articulate the skeleton and thus are often called skeletal muscles. They are attached to the bones by tendons, which have some elasticity provided by the proteins collagen and elastin, the major…

economic stabilizer: Effects of business contraction: When business begins to contract, the first manifestation is a decrease in investment that causes unemployment in the capital goods industries; the unemployed are deprived of the cash wage receipts required to make their consumption demands effective. Unemployment then spreads to consumer goods industries.…

combinatorics: Planar graphs: …is said to be a contraction of G if G* can be obtained from G by a sequence of elementary contractions. The following is another characterization of a planar graph due to the German mathematician K. Wagner in 1937.

mountain: Tectonic processes that destroy elevated terrains: Similarly, the cooling and associated thermal contraction of the outer part of the Earth leads to a reduction of the average height of a mountain belt.

construction: Construction: …organization, often called a general contractor, which takes the primary responsibility for executing the building and signs a contract to do so with the building user. The cost of the contract is usually an agreed lump sum, although cost-plus-fee contracts are sometimes used on large projects for which construction begins…

Lindsay Anderson: …Storey’s plays In Celebration (1969), The Contractor (1969), Home (1970), and The Changing Room (1971). His subsequent films included O Lucky Man! (1973), In Celebration (1974), Britannia Hospital (1982), and The Whales of August (1987). His later stage productions included Storey’s The March on

Battle of Wake Island: …consortium of civilian firms called Contractors Pacific Naval Air Bases (CPNAB) began construction of military facilities on the atoll. By December CPNAB had more than 1,100 construction workers toiling on Wake, but they did not complete their work before the outbreak of war between Japan and the United States. A…

warranty: History: The United Nations Convention on Contracts for the International Sale of Goods (CISG) provided similar warranty rights and duties for certain buyers and sellers involved in global commerce. CISG was originally passed in 1980 and was adopted by almost 80 countries, including the United States. Its warranty provisions…

insurance: Contract law: The requirement of capacity to contract usually means that the individual obtaining insurance must be of a minimum age and must be legally competent; the contract will not hold if the insured is found to be insane or intoxicated or if the insured is a corporation operating outside…

hypothec: Contractual hypothecs are those made between individuals, and they must be notarized before witnesses. It is necessary to state the amount to be secured in the document. Judicial hypothecs are instituted by the court against all the property, present and future, of a debtor. Legal…

license: Contractual license provides an express or implied permission to enter or use the property in exchange for some consideration. For example, the purchase of a movie ticket allows the ticket holder a license to enter the theatre at a particular time. Licenses that are acquired…

social contract, in political philosophy, an actual or hypothetical compact, or agreement, between the ruled or between the ruled and their rulers, defining the rights and duties of each. In primeval times, according to the theory, individuals were born into an anarchic state of nature, which was

contredanse, genre of dance for several couples. The contredanse was an 18th-century French development of the English country dance (q.v.) and was performed into the 19th century by French, English, and German aristocrats and bourgeoisie. Contredanses at first used only the country dance’s

Marxism: Maoism: …the nature and role of contradictions in socialist society. For Mao, every society, including socialist (communist) society, contained “two different types of contradictions”: (1) antagonistic contradictions—contradictions between us (the people) and our enemies (the Chinese bourgeoisie faithful), between the imperialist camp and the socialist camp, and so forth—which are resolved…

laws of thought: …laws of logic: (1) the law of contradiction, (2) the law of excluded middle (or third), and (3) the principle of identity. The three laws can be stated symbolically as follows. (1) For all propositions p, it is impossible for both p and not p to be true, or: ∼(p…

contradictories and contraries: Two categorical propositions are contradictories if they are opposed in both quantity and quality; i.e., if one is universal (“every”) and the other particular (“some”) and one an affirmation and the other a denial. For example, “Every S is P” and “Some S is not P” are contradictories. Some…

contradictories and contraries, in syllogistic, or traditional, logic, two basically different forms of opposition that can obtain between two categorical propositions or statements formed from the same terms. Two categorical propositions are contradictories if they are opposed in both quantity and

contrail, streamer of cloud sometimes observed behind an airplane flying in clear cold humid air. A contrail forms when water vapour produced by the combustion of fuel in airplane engines condenses upon soot particles or sulfur aerosols in the plane’s exhaust. When the ambient relative humidity is

tamoxifen: …increase in risk of developing contralateral estrogen receptor-negative breast cancer—a form of the disease that is difficult to treat and is associated with a poor prognosis. Another serious side effect of tamoxifen treatment is an increased risk of thrombosis, which may require patients to take an anticoagulant.

contralto, in vocal music, the second-highest voice in four-part music, also called alto