razor clam Any of several species of marine clams (family Solenidae) common in intertidal sands and muds, particularly of temperate seas. Razor clams have narrow and elongated shells (shaped like straight razors) up to 8 in. (20 cm) long. A large active foot enables them to move rapidly up and down within their burrow and retreat quickly when dis¬ turbed. With their short siphons (tubes) they feed on particulate material in seawater. Some species can swim short distances by jetting water through their siphons.
razorback whale See fin whale
RCA Corp. Major U.S. electronics and broadcasting conglomerate that was purchased by the General Electric Co. (GE) in 1986. RCA’s subsid¬ iaries at the time of the acquisition included NBC, which is managed as a separate division within GE. RCA was founded as the Radio Corp. of America by General Electric in 1919 to acquire Marconi Wireless Tele¬ graph Co. of America, at that time the only company capable of handling commercial transatlantic radio communications. RCA founded NBC in 1926 to manage radio broadcasting operations for GE, AT&T, and West- inghouse. An antitrust suit against the three latter companies in 1932 caused RCA and its NBC unit to become independent. In 1939 RCA developed the first experimental television set, and its black-and-white sets went on the market seven years later. After consolidating most of RCA’s operations into GE’s businesses, in 1987 General Electric sold RCA’s consumer-electronics division to the French corporation Thomson-Brandt, SA (later Thomson SA). Within GE, RCA’s core products are in military and space electronics and satellite communications.
Re \'ra\ or Ra \'ra\ In ancient Egyptian religion, the creator god and god of the sun. He was believed to sail across the sky in his solar bark and at night to travel in another bark through the underworld, where he had to vanquish a serpent before he could be born again. As the creator, he rose from the ocean of chaos, creating himself and then engendering eight other gods. From the 4th dynasty, kings held the title Son of Re, and Re later became part of the throne name they adopted at accession and was appended to the names of such gods as Amon and Sebek.
reactance Measure of the opposition that an electrical circuit or a part of a circuit presents to electric current (see electrical impedance) insofar as the current is varying or alternating. Steady electric currents flowing along conductors in one direction undergo opposition called electrical resistance, but no reactance. Reactance is present in addition to resistance when con¬ ductors carry alternating current. Reactance also occurs for short intervals when direct current is changing as it approaches or departs from steady flow (e.g., when switches are closed or opened). Reactance is of two types, inductive and capacitive. Inductive reactance is associated with the vary¬ ing magnetic field that surrounds a wire or a coil carrying a current. Capacitive reactance is associated with the changing electric field between two conducting surfaces (plates) separated from each other by an insu¬ lating medium. The ohm is the unit of reactance.
reaction, heat of Amount of heat that must be added or removed dur¬ ing a chemical reaction to keep all substances involved at the same tem¬ perature. If it is positive (heat must be added), the reaction is endothermic; if it is negative (heat is given off), the reaction is exothermic. Accurate heat of reaction values are needed for proper design of equipment used in chemical processes; they are usually estimated from compiled tables of thermodynamics data (heats of formation and heats of combustion of many known materials). The activation energy is unrelated to the heat of reaction.
reaction rate Speed at which a chemical reaction proceeds, in terms of amount of product formed or amount of reactant consumed per unit of time. The reaction rate depends on the nature of the reacting substances and the type of chemical change, as well as temperature and pressure, especially if GASes are involved. In general, the reactions of ions occur very rapidly, but those in which covalent bonds are formed or broken are slower. Catalysts usually accelerate reaction rates. The prediction, mea¬ surement, and interpretation of reaction rates are subjects of the branch of chemistry known as chemical kinetics. See also mass action, law of.
read-only memory See ROM
Reade, Charles (b. June 8, 1814, near Ipsden, Oxfordshire, Eng.—d. April 11, 1884, London) English novelist and dramatist. Though trained in law and an administrator at Oxford University, he put much of his time and resources into writing and staging his melodramatic plays. His nov¬ els expose, with passionate indignation, the social injustices of his times. He is best remembered for the historical romance The Cloister and the Hearth (1861). His other novels include It Is Never Too Late to Mend (1856), attacking prison conditions; Hard Cash (1863), on the abuse of mental patients; and Put Yourself in His Place (1870), about terrorism by trade unionists.
Reader's Digest U.S.-based monthly magazine. Founded by DeWitt and Lila Wallace, it was first published in 1922 as a digest of articles of topical interest and entertainment value condensed from other periodicals. From 1934 it published condensed versions of current books; later it began publishing books containing original material. Though initially conceived as an impartial journal, the Digest has tended to reflect its publishers’ generally conservative outlook. It probably has the largest circulation of any periodical in the world, appearing in dozens of editions and a wide variety of languages worldwide.
Reading Vre-diqX Town and unitary authority (pop., 2001: 143,124), county seat of Berkshire, England, west of London. Reading was a Danish encampment as early as ad 871. It was given a town charter by King Henry III in 1253; that charter was confirmed by succeeding sovereigns. Between the 12th and 16th centuries Reading was dominated by a struggle for privileges between the Benedictine abbey founded in 1121 and the emer¬ gent merchants’ guild. By the 17th century the town’s trade, notably in clothing, had begun to decline. In the 18th century the chief trade was in malt. In the city’s public gardens are the ruins of the abbey, which was dissolved by Henry VIII. The structure was destroyed during the English Civil Wars, during which time the town in general also suffered severely.
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1596 I ready-made ► rebbe
In Reading Gaol, adjoining the ruins, Oscar Wilde was imprisoned, and it was there that he wrote The Ballad of Reading Gaol. The city is now an agricultural centre noted for the bulbs produced in its nurseries. It is the site of a university, and its industries include computer production and malting and brewing.
ready-made Everyday object selected and designated as art. The name was coined by Marcel Duchamp, whose first ready-mades included a snow shovel that he picked up on a snowy day in New York, and a wheel mounted on a stool (1913). They represented a protest against the exces¬ sive importance attached to works of art. Duchamp’s anti-aesthetic ges¬ tures made him one of the leading Dadaists of his day, and his ready¬ made concept, though widely regarded for decades as an insult to art, was adapted by such later artists as Robert Rauschenberg, Andy Warhol, and Jasper Johns.