ray, extremely flat-bodied cartilaginous marine fish, related to the shark. The pectoral fins of most rays are developed into broad, flat, winglike appendages, attached all along the sides of the head; the animal swims by rippling movements of these wings. Most rays have slender whiplike tails. The eyes and spiracles are located on top of the head, the mouth and the gill slits on the underside. Many rays are bottom dwellers, lying like rugs on the seafloor; others inhabit the upper waters. Bottom-dwelling rays breathe by taking in water through the spiracles, rather than through the mouth as most fishes do, and passing it out through the gills. Rays feed on a variety of smaller animals; the heavy, rounded teeth of most species are adapted to crushing the shells of snails and clams.

Types of Rays

The rays, which form the order Batoidea, are divided into seven families. The largest are the mantas, also called devil rays and devilfish (family Mobulidae). These are top-swimming forms which may weigh up to 3,000 lb (1360 kg), with a width of up to 22 ft (7 m). Unlike most rays, mantas are filter-feeders; the manta uses a pair of horns at the front of the head to drive small prey into its mouth; there the prey is caught in a strainer and swallowed, the water passing out through the manta's gills. Electric rays, or torpedos (family Torpedinidae), have electric organs in their wings that generate electric current, used to immobilize prey and for defense. The current is strong enough to stun humans, and it is said that the ancient Greeks used these fish for shock therapy. Skates (family Rajidae), which are sometimes caught for food, are bottom dwellers with nearly disk-shaped bodies and short tails; some species have electric organs in their tails. The stingrays, or whiprays (family Dasyatidae), have rows of spines along their tails, which are generally much longer than their bodies. The stingray inflicts wounds by lashing with its tail; the spines contain a poison that causes pain and can be fatal to humans. Most of the eagle rays and bat rays (family Mylobatidae) bear a single poison spine on the tail. The guitarfishes (family Rhinobatidae) are sharklike in form, having well-developed tails used for swimming and smaller pectoral fins than most rays; however, the fins are attached, as in all rays, above the gills, giving these fishes a broad-headed appearance. Sawfishes (family Pristidae) are similar in body form, but have long, flat snouts with a row of toothlike projections on either side. Some species reach a total length of 20 ft (6 m), with snouts 6 ft (1.8 m) long and 1 ft (30 cm) wide. They use these ponderous weapons to slash and impale small fishes and to probe in the mud for burrowing animals. Sawfishes should not be confused with saw sharks, which are true sharks.

Reproduction and Distribution

Fertilization is internal in rays. Most bear live young, but the skates lay flattened, rectangular eggs, enclosed in leathery shells, with tendrils at the corners for anchorage. Empty egg cases of this type are found on beaches and are known as mermaids' purses. Most ray families have a more or less cosmopolitan distribution in tropical and subtropical marine waters; some include temperate or cold-water species. Some rays can live in brackish bays and estuaries, and the sawfish enters freshwater rivers and lakes.

Classification

Rays are classified in the phylum Chordata, subphylum Vertebrata, class Chondrichthyes, subclass Elasmobranchii, order Batoidea.

ray, in physics, term denoting the straight line along which light or other form of radiation is propagated from its source. It generally refers to the line of propagation of waves but is also applied to streams of particles such as the electrons emitted from a cathode or particles emitted by substances exhibiting radioactivity. See cosmic rays; X ray.

gamma-ray astronomy, study of astronomical objects by analysis of the most energetic electromagnetic radiation they emit. Gamma rays are shorter in wavelength and hence more energetic than X rays (see gamma radiation) but much harder to detect and to pinpoint. X rays and some gamma rays are produced throughout the universe by the same catastrophic astrophysical events, such as supernovas and black holes, and gamma-ray astronomy can be considered an extension of X-ray astronomy to the extreme shortwave end of the spectrum.

Gamma rays are difficult to observe from ground-based telescopes due to atmospheric interference, and high-altitude balloons, sounding rockets, and orbiting observatories are therefore used. Some ground-based facilities, including a large 33-ft (10-m) dish with many small mirrors at Mount Hopkins, Ariz., are successful gamma-ray collectors because they record the radiation emitted by very-high-energy gamma rays as they generate high-speed electrons in the upper atmosphere. Another approach to detecting this radiation is the Milagro detector in the Jemez Mountains of New Mexico. It consists of hundreds of phototubes floating within a pond containing 6 million gallons of water; through interactions with the water, the radiation generates weak trails of light that are detected by the phototubes, yielding data about the energy and direction of the gamma rays.

Cygnus X-3 and the Crab and Vela pulsars are well known gamma-ray sources. In addition, gamma rays have been detected as general background radiation concentrated along the plane of the Milky Way. These gamma rays may result from cosmic rays interacting with gaseous matter in the interstellar medium. Gamma rays from outside the Milky Way have been found emanating from radio galaxies (galaxies whose radio emissions constitute an extraordinarily large amount of their total energy output), Seyfert galaxies (galaxies with extremely bright cores—called Active Galactic Nuclei [AGN]—that are strong emitters of radio waves, X rays, and gamma rays), and supernovas.

The first gamma-ray telescope was carried into orbit on the Explorer XI satellite in 1961. Additional gamma-ray experiments flew on the OGO, Vela, and Russian Cosmos series of satellites. The Orbiting Solar Observatory OSO-3 made the first certain detection of celestial gamma rays in 1972, and OSO-7 detected gamma-ray emission lines in the solar spectrum. However, the first satellite designed as a "dedicated" gamma-ray mission was the second Small Astronomy Satellite (SAS-2) in 1972. In 1975 the European Space Agency launched the COS-B satellite to survey the sky for gamma-ray sources. SAS-2 and COS-B confirmed the earlier findings of gamma-ray background radiation and also detected a number of point sources, but the poor resolution of the instruments made it impossible to associate most of these point sources with individual stars or stellar systems. The third High Energy Astronomy Observatory (HEAO-3), launched in 1979, studied both cosmic rays and gamma radiation. A number of satellites launched during the 1980s carried gamma-ray experiments into orbit. The Compton Gamma-Ray Observatory (CGRO), launched in 1991, carried a collection of four instruments that were larger and more sensitive than any gamma-ray telescope previously orbited. In addition to creating a comprehensive map of celestial gamma-ray sources and demonstrating that gamma-ray bursts are evenly distributed across the sky (which suggests that the radiation is coming from the distant reaches of the universe and not just from within the Milky Way), CGRO detected a number of "firsts," such as the first gamma-ray quasar. During the 1990s a number of planetary probes, such as Mars Observer (1983), and earth-orbiting satellites, such as Minisat 1 (1997), carried gamma-ray detection and measurement devices as part of their instrumentation.

The turn of the century saw designs for gamma-ray astronomy satellites that allow for imaging resolution and spectral resolution powers never before possible. Launchings of orbiting gamma-ray observatories include missions such as the High Energy Transient Explorer (HETE-2), launched in 2000, the European Space Agency's International Gamma-Ray Astrophysics Laboratory (INTEGRAL), launched in 2002, and the Swift Gamma Ray Burst Explorer, launched in 2004.

In 1967 a Vela military satellite designed to detect nuclear explosions discovered the first gamma-ray bursts (GRBs). These events are very short-lived, lasting from about 50 milliseconds to, in extreme cases, several minutes, and occur on an almost daily basis. It has been suggested that the formation of black holes is associated with these intense gamma-ray bursts. Beginning with a giant star collapsing on itself or the collision of two neutron stars, waves of radiation and subatomic particles are propelled outward from the nascent black hole and collide with one another, releasing the gamma radiation. Also released is longer-lasting—from a few days to several years—electromagnetic radiation (called the afterglow) in the form of X rays, radio waves, and visible wavelengths that can be used to pinpoint the location of the disturbance.

cathode-ray tube, special-purpose electron tube in which electrons are accelerated by high-voltage anodes, formed into a beam by focusing electrodes, and projected toward a phosphorescent screen that forms one face of the tube. The beam of electrons leaves a bright spot wherever it strikes the phosphor screen. To form a display, or image, on the screen, the electron beam is deflected in the vertical and horizontal directions either by the electrostatic effect of electrodes within the tube or by magnetic fields produced by coils located around the neck of the tube. Some cathode-ray tubes can produce multiple beams of electrons and have phosphor screens that are capable of displaying more than one color. Cathode-ray tubes are used in television sets, computer monitors, automated teller machines, oscilloscopes, and radar displays.

X-ray crystallography, the study of crystal structures through X-ray diffraction techniques. When an X-ray beam bombards a crystalline lattice in a given orientation, the beam is scattered in a definite manner characterized by the atomic structure of the lattice. This phenomenon, known as X-ray diffraction, occurs when the wavelength of X-rays and the interatomic distances in the lattice have the same order of magnitude. In 1912, the German scientist Max von Laue predicted that crystals exhibit diffraction qualities. Concurrently, W. Friedrich and P. Knipping created the first photographic diffraction patterns. A year later Lawrence Bragg successfully analyzed the crystalline structures of potassium chloride and sodium chloride using X-ray crystallography, and developed a rudimentary treatment for X-ray/crystal interaction (Bragg's Law). Bragg's research provided a method to determine a number of simple crystal structures for the next 50 years. In the 1960s, the capabilities of X-ray crystallography were greatly improved by the incorporation of computer technology. Modern X-ray crystallography provides the most powerful and accurate method for determining single-crystal structures. Structures containing 100-200 atoms now can be analyzed on the order of 1-2 days, whereas before the 1960s a 20-atom structure required 1-2 years for analysis. Through X-ray crystallography the chemical structure of thousands of organic, inorganic, organometallic, and biological compounds are determined every year.

X-ray astronomy, study of celestial objects by means of the X rays they emit, in the wavelength range from 0.01 to 10 nanometers. X-ray astronomy dates to 1949 with the discovery that the sun emits X rays. Since X rays could not be observed from ground-based telescopes, V-2 rockets launched from White Sands, N.Mex., occasionally carried telescopes to study solar X-ray emissions. In 1962 a group led by R. Giacconi launched a small rocket from White Sands to search for celestial sources of X rays with instruments similar to Geiger counters. During the 5-min flight the experiment discovered an X-ray source now called Scorpius X-1, a close binary star in which one star expels gas onto a very dense neighbor, which may be a white dwarf, a neutron star, or a black hole. This mission also found that the earth is bathed in diffuse X rays coming from all directions. Soon afterward X-ray emissions were found coming from the Crab Nebula and the radio galaxies (galaxies whose radio emissions constitute an extraordinarily large amount of their total energy output) Centaurus A and Virgo A. Other types of galaxies, particularly Seyfert galaxies (galaxies with extremely bright cores that are strong emitters of radio waves, X rays, and gamma rays), also emit X rays. The center of our galaxy is a strong X-ray source, which is an indicator of the violent activity taking place there.

In 1970 the Uhuru satellite, one of NASA's small astronomy satellites, began to look specifically for X-ray sources. Uhuru used detectors filled with argon, in which incoming X radiation gives off electrons in amounts proportional to its strength. Uhuru mapped more than 400 sources and discovered a series of X-ray binary stars in which ordinary stars orbit neutron stars that emit X rays. One of these sources, Cygnus X-1, is an object with ten times the mass of the sun. Too massive to be a neutron star, it is possibly a black hole.

Much of the data in X-ray astronomy is now gathered by orbiting satellites. In addition to the United States, Germany and Japan are among the countries having X-ray satellites. In the 1970s the Skylab space station and Orbiting Solar Observatory satellites continued the study, as did the Solar Maximum Mission the following decade. A series of High Energy Astrophysical Observatories (HEAO) were launched during the late 1970s to study X rays, cosmic rays, and gamma rays. HEAO-1, launched in 1977, increased the number of known X-ray sources from 350 to 1,500. HEAO-2—also known as the Einstein Observatory—carried the largest X-ray telescope ever built. It detected several thousand new X-ray sources in our galaxy and beyond, discovered that cataclysmic variable stars in our own galaxy emit X rays when they are in outburst, achieved the first unambiguous detection of X rays from ordinary stars other than the sun, and obtained the first X-ray images of supernova remnants, pulsars, and star clusters. As a result, supernova remnants mapped in X-ray wavelengths can be compared with visible light and radio images. In an example of cooperation between amateur and professional astronomers, the Einstein Observatory was turned toward SS Cygni (see variable star) whenever amateur astronomers with backyard telescopes reported it in outburst. The few days' duration of these outbursts allowed enough time to change the satellite's observing schedule so that it could examine the star, and it discovered the source of the star's X-ray emissions.

During the 1980s the European, Russian, and Japanese space agencies continued to launch successful X-ray astronomy missions, such as the European X-ray Observatory Satellite (EXOSAT), Granat, the Kvant module (of the Mir space station), Tenma, and Ginga. These missions were more modest in scale than the HEAO program in the 1970s and were directed toward in-depth studies of known phenomena.

In 1990, ROSAT [Roentgen Satellite], a joint project of Germany, the United States, and Great Britain, was launched. Operational until 1999, it was instrumental in the discovery of X-ray emissions from comets and conducted an all-sky survey in the X-ray region of the spectrum. Five other satellites launched in the 1990s are still operational. ALEXIS [Array of Low Energy X-ray Imaging Sensors] was launched in 1993; a minisatellite containing six coffee-can-sized wide-angle, ultrasoft-X-ray telescopes, it provided the data for a unique sky map for studying celestial flashes of soft X rays. Also launched in 1993, the Advanced Satellite for Cosmology and Astrophysics is a joint Japanese-American project; containing four X-ray telescopes, its primary purpose is the X-ray spectroscopy of such astrophysical entities as quasars and cosmic background X radiation. In 1995, NASA orbited the Rossi X-ray Timing Explorer (RXTE) to study the variations in the emission of such X-ray sources as black-hole candidates, active galactic nuclei, white dwarf stars, neutron stars, and other high-energy sources. The RXTE played a key role in the discovery in 1996 of a "pulsing burster" located near the center of the Milky Way. Unlike other X-ray sources, this one burst, oscillated, and flickered simultaneously, with bursts lasting from 6 to 100 seconds. Before it burned out, the unexplained object was the brightest source of X rays and gamma rays in the sky, radiating more energy in 10 seconds than the sun does in 24 hours. BeppoSAX, a joint Italian-Dutch satellite, was launched in 1996. When on Dec. 14, 1997, for 1 or 2 seconds the most energetic burst of gamma radiation ever detected was recorded by the Compton Gamma Ray Observatory, BeppoSAX recorded the X-ray afterglow of the burst, thereby providing a relatively accurate location for the source. The Chandra X-ray Observatory was deployed from a shuttle and boosted into a high earth orbit in 1999; it focuses on such objects as black holes, quasars, and high-temperature gases throughout the X-ray portion of the electromagnetic spectrum. Also launched in 1999 was X-ray Multimirror Mission, an ESA satellite that carries an optical-ultraviolet telescope together with three parallel mounted X-ray telescopes, allowing it to simultaneously observe phenomena in two regions of the spectrum.

X ray, invisible, highly penetrating electromagnetic radiation of much shorter wavelength (higher frequency) than visible light. The wavelength range for X rays is from about 10^-8 m to about 10^-11 m, or from less than a billionth of an inch to less than a trillionth of an inch; the corresponding frequency range is from about 3 × 10¹⁶ Hz to about 3 × 10¹⁹ Hz (1 Hz = 1 cps).

Production of X Rays

An important source of X rays is synchrotron radiation. X rays are also produced in a highly evacuated glass bulb, called an X-ray tube, that contains essentially two electrodes—an anode made of platinum, tungsten, or another heavy metal of high melting point, and a cathode. When a high voltage is applied between the electrodes, streams of electrons (cathode rays) are accelerated from the cathode to the anode and produce X rays as they strike the anode.

Two different processes give rise to radiation of X-ray frequency. In one process radiation is emitted by the high-speed electrons themselves as they are slowed or even stopped in passing near the positively charged nuclei of the anode material. This radiation is often called brehmsstrahlung [Ger.,=braking radiation]. In a second process radiation is emitted by the electrons of the anode atoms when incoming electrons from the cathode knock electrons near the nuclei out of orbit and they are replaced by other electrons from outer orbits. The spectrum of frequencies given off with any particular anode material thus consists of a continuous range of frequencies emitted in the first process, and superimposed on it a number of sharp peaks of intensity corresponding to discrete frequencies at which X rays are emitted in the second process. The sharp peaks constitute the X-ray line spectrum for the anode material and will differ for different materials.

Applications of X Rays

Most applications of X rays are based on their ability to pass through matter. This ability varies with different substances; e.g., wood and flesh are easily penetrated, but denser substances such as lead and bone are more opaque. The penetrating power of X rays also depends on their energy. The more penetrating X rays, known as hard X rays, are of higher frequency and are thus more energetic, while the less penetrating X rays, called soft X rays, have lower energies. X rays that have passed through a body provide a visual image of its interior structure when they strike a photographic plate or a fluorescent screen; the darkness of the shadows produced on the plate or screen depends on the relative opacity of different parts of the body.

Photographs made with X rays are known as radiographs or skiagraphs. Radiography has applications in both medicine and industry, where it is valuable for diagnosis and nondestructive testing of products for defects. Fluoroscopy is based on the same techniques, with the photographic plate replaced by a fluorescent screen (see fluorescence; fluoroscope); its advantages over radiography in time and cost are balanced by some loss in sharpness of the image. X rays are also used with computers in CAT (computerized axial tomography) scans to produce cross-sectional images of the inside of the body.

Another use of radiography is in the examination and analysis of paintings, where studies can reveal such details as the age of a painting and underlying brushstroke techniques that help to identify or verify the artist. X rays are used in several techniques that can provide enlarged images of the structure of opaque objects. These techniques, collectively referred to as X-ray microscopy or microradiography, can also be used in the quantitative analysis of many materials. One of the dangers in the use of X rays is that they can destroy living tissue and can cause severe skin burns on human flesh exposed for too long a time. This destructive power is used in X-ray therapy to destroy diseased cells.

Discovery and Early Scientific Use

X rays were discovered in 1895 by W. C. Roentgen, who called them X rays because their nature was at first unknown; they are sometimes also called Roentgen, or Röntgen, rays. X-ray line spectra were used by H. G. J. Moseley in his important work on atomic numbers (1913) and also provided further confirmation of the quantum theory of atomic structure. Also important historically is the discovery of X-ray diffraction by Max von Laue (1912) and its subsequent application by W. H. and W. L. Bragg to the study of crystal structure.

Wilbur, Ray Lyman, 1875-1949, American public official and educator, b. Boonesboro, Iowa, grad. Stanford (B.A., 1896; M.A., 1897) and Cooper Medical College, San Francisco, 1899. After studying medicine abroad, Wilbur became a professor (1909-16) and dean (1911-16) of the medical school at Stanford. In 1916 he became president of Stanford. In World War I he served with the U.S. Food Administration and was (1929-33) Secretary of the Interior under President Hoover. He retired as college president in 1943. The March of Medicine (1938) and Human Hopes (1940) are collections of his speeches and writings.

Röntgen ray: see X ray.

Roentgen ray: see X ray.

Robinson, Sugar Ray, 1920-89, American boxer, b. Detroit. His real name was Walker Smith. He began boxing after three years of high school in New York City. Having won all his amateur fights (about 90), including the Golden Gloves featherweight title, Robinson turned professional in 1940. He won the welterweight championship in 1946 by defeating Tommy Bell and the middleweight championship for the first time in 1951 by knocking out Jake La Motta. When Robinson retired from boxing as middleweight champion in 1952 he had lost only three times in 137 bouts. Returning to boxing in 1955, he was the first boxer ever to regain a title after retiring. Robinson became the first man in boxing history to win a divisional (weight class) world championship five times when he regained the middleweight title in 1958 by defeating Carmen Basilio; he lost the title in 1960 to Paul Pender. In his prime, the swift, hard-punching Robinson was rated the best boxer, pound for pound, of his time.

Ray, Satyajit, 1921-92, Indian film director, b. Calcutta (now Kolkata). His subtle, austere, and delicately lyrical films made him one of the outstanding filmmakers of the 20th cent.; he was the first Indian director to win international acclaim. During his formative years he was profoundly influenced by the humanism of Rabindranath Tagore, at whose university he studied. Ray began his career as a layout artist, art director, and illustrator. His early reputation was built on a trilogy of luminous neorealist films that portrayed the everyday life of a Bengali family and the childhood, youth, and manhood of a character called Apu. Pather Panchali (1955), his first film, was an immediate success and a Grand Prix winner at the Cannes Festival. It was followed by Aparajito (1956) and The World of Apu (1959). The films of this "Apu Trilogy" remain his best known works.

Ray's recurrent themes—the life of Bengal's various social classes, the conflict of old and new values, and the effects of India's rapidly changing economic and political conditions—are evident throughout his oeuvre. His more than 30 films include The Music Room (1958), Charulata (1964), The Target (1972), Distant Thunder (1973), The Home and the World (1984), The Visitor (1991), and The Stranger (1992). Over the years, he received many prizes, including an Academy Award for lifetime achievement (1992). Ray was also a screenwriter, wrote the musical scores for many of his films, and was intimately involved with all the elements of their production.

Ray, Man, 1890-1976, American photographer, painter, and sculptor, b. Philadelphia. Along with Marcel Duchamp, Ray was a founder of the Dada movement in New York and Paris. He is celebrated for his later surrealist paintings and photography. Among his inventions is the rayograph, a photograph obtained by the direct application of objects of varying opacity to a light-sensitive plate. His works include the painting The Rope Dancer Accompanies Herself with Her Shadows and the enigmatic sculpture Gift (both: Mus. of Modern Art, New York City). Ray also made several surrealist films, of which L'Étoile de Mer (1928) is the best known.

Ray or Wray, John, 1627-1705, English naturalist. He was extremely influential in laying the foundations of systematic biology. With his pupil Francis Willughby, he planned a complete classification of the vegetable and animal kingdoms and toured Europe collecting specimens. On Willughby's death, Ray organized and published the material left by his friend. Ray's own work—the botanical part of the project—includes the important Historia plantarum (3 vol., 1686-1704). Ray was the first to name and make the distinction between monocotyledons and dicotyledons. He was also the first to define and explain the term species in the modern sense of the word. Ray studied and wrote on quadrupeds, reptiles, and birds. The Ray Society for the publication of scientific works was founded in his honor in 1844.

Palmer, Ray, 1808-87, American Congregational clergyman and hymn writer, b. Little Compton, R.I., grad. Yale, 1830. He held pastorates in Bath, Maine (1835-50), and Albany, N.Y. (1850-66). He is remembered chiefly for the hymn "My Faith Looks up to Thee" (1830), a worldwide favorite, for which Lowell Mason wrote the tune Olivet.

Nagin, Ray (Clarence Ray Nagin, Jr.), 1956-, African-American politician, b. New Orleans. A Louisiana cable-television executive before entering politics, Nagin won the 2002 mayoral election handily as a reform candidate, despite never before holding elective office. He came to wide public attention in 2005 when New Orleans was hit by catastrophic flooding in the wake of Hurricane Katrina. Thousands of buildings were destroyed and hundreds died, and the mayor was widely criticized for the city's lack of a workable evacuation plan and his delay in ordering the city's mandatory evacuation. At the same time, he vociferously criticized state and federal officials for their slow and ineffective reaction to the crisis. Vowing to resurrect the city, Nagin was narrowly reelected in 2006.

Lankester, Sir Edwin Ray, 1847-1929, English zoologist. He was a professor at University College, London (1874-90) and Oxford (1891-98) and was director of the natural history department of the British Museum (1898-1907). He was a founder (1884) of the Marine Biological Association, which established an important station at Plymouth. Influential as teacher and writer on biological theories, comparative anatomy, and evolution, Lankester studied the protozoa, mollusca, and arthropoda. He was knighted in 1907.

Kroc, Ray (Raymond Albert Kroc), 1902-84, American fast-food restauranteur and franchiser, b. Chicago. Kroc held several jobs before becoming (1937) the distributor for a blender that simultaneously prepared several milkshakes. Visiting a small but profitable San Bernadino, Calif., restaurant owned by brothers Mac and Dick McDonald, he was impressed by the fast assembly-line fashion preparation of burgers, fries, sodas, and shakes. Kroc acquired the business's franchising rights and in 1955 founded the McDonald's Corp. Six years later he bought out the brothers. Using quality, service, cleanliness, and value as a commercial mantra, and maintaining strict uniformity of product, McDonald's grew quickly, as franchises opened throughout the country and menu items were gradually added. Kroc served as president (1955-68), chairman of the board (1968-77), and then senior chairman until his death. By then, McDonald's had changed America's eating habits, with more than 7,500 restaurants in operation and annual sales topping $8 billion.

Heseltine, Michael Ray Dibdin, 1933-, British politician. After studying law at Oxford, he built a successful career in publishing before entering the House of Commons as a Conservative in 1966. He held junior posts in the Heath government (1970-74). In Margaret Thatcher's government, he was secretary for the environment (1979-83) and then secretary for defense in 1983, resigning in protest over his treatment in the 1986 Westland helicopter affair, which involved the leak of a confidential communication. He was regarded as Thatcher's strongest rival and initiated a challenge to her leadership in 1990. She resigned, but John Major assumed the prime ministership. Heseltine again became environmental secretary and was responsible for repealing the highly unpopular poll tax. In 1992 he became president of the Board of Trade and secretary for trade and industry; from 1995 to 1997 he was deputy prime minister under Major.

Gamma-Ray Observatory: see gamma-ray astronomy.

Eames, Ray Kaiser: see under Eames, Charles.

Compton Gamma-Ray Observatory: see gamma-ray astronomy.

Charles, Ray (Ray Charles Robinson), 1930-2004, African-American musician and composer, b. Albany, Ga. Blinded at age seven, he was raised in Florida and at 16 began singing in a local hillbilly group. Two years later he moved to Seattle, where he formed his own trio. Charles rose to fame in the 1950s singing rhythm-and-blues tunes in an exuberant yet sophisticated style to the accompaniment of his piano and band. He had his first national recorded hit, "I've Got a Woman," in 1955. Combining sacred styles with the secular and rooted in gospel music and the blues, his work infused soul into a variety of genres, and it influenced, and was influenced by, jazz and rock music. Among Charles's greatest hits were "Whad'd I Say" (1959), "Georgia on My Mind" (1960), and his soulful rendition of "America the Beautiful" (1984). An outstanding live performer, he also recorded more than 60 albums and won 12 Grammy awards. He was inducted into the Rock-and-Roll Hall of Fame in 1986.

Bradbury, Ray, 1920-, American writer, b. Waukegan, Ill. A popular and very prolific writer of science fiction, Bradbury skillfully combines social and technological criticism with delightful fantasy. His best-known work is probably The Martian Chronicles (1950), the tale of the ruin of Martian civilization by greedy and corrupt earthlings, which was made into a film (1966) and a TV miniseries (1980). His short-story collections include The Golden Apples of the Sun (1953), The Last Circus and the Executioner (1980), The Toynbee Convector (1988), Quicker than the Eye (1996), and Driving Blind (1997); among his novels are Fahrenheit 451 (1953, film 1966), Dandelion Wine (1957), Something Wicked This Way Comes (1962, film 1983), The Halloween Tree (1972), and A Graveyard for Lunatics (1990). Bradbury has also written scripts for plays and films, a detective novel, children's stories, and poetry.

Baker, Ray Stannard, pseud. David Grayson, 1870-1946, American author, b. Lansing, Mich., grad. Michigan State College (now Michigan State Univ.), 1889. At first a Chicago newspaper reporter, he joined the staff of McClure's Magazine in 1897, for which he wrote some famous muckraking articles. With other McClure's contributors he purchased the American Magazine in 1906 and helped edit it. The first book of quiet country sketches by "David Grayson," Adventures in Contentment, appeared in 1907; the series continued with Great Possessions (1917), The Countryman's Year (1936), and others. An intimate of Woodrow Wilson, Baker was sent to Europe in 1918 as one of the president's special agents to study the war situation. At the peace conference at Versailles, Baker was director of the press bureau of the American peace commission. Afterward he wrote Woodrow Wilson and World Settlement (3 vol., 1922), a history of the peace conference based largely on the Wilson papers. With W. E. Dodd he edited Wilson's Public Papers (6 vol., 1925-26). His authoritative biography of Wilson (8 vol., 1927-39), for which he used the president's personal papers, won the Pulitzer Prize for biography in 1940 for the last two volumes.

Any of 300–350 mostly marine species of cartilaginous fish (order Batoidei) found worldwide and classified as electric rays, sawfishes, skates, and stingrays. Many species are slow-moving bottom-dwellers. The gill openings and mouth are on the underside of the flattened body. Winglike pectoral fins extend along the sides of the head. All but electric rays have a long, slender tail, often with saw-edged, venomous spines, and rough, often spiny, skin. Seealso manta ray.

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or devil ray or devilfish

Any of several genera of warm-water marine rays, constituting the family Mobulidae, that are wider than they are long. Extensions of the pectoral fins project from the front of the head, looking like devils' horns; these sweep plankton and small fishes into their mouths. The long, whiplike tail may have one or more stinging spines. Mantas swim near the surface by flapping their pectoral fins. The largest species, the powerful but inoffensive Atlantic manta, or giant devil, ray (Manta birostris), may grow to over 23 ft (7 m) wide; contrary to old tales, it does not envelop and eat divers.

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Penetrating very short-wavelength electromagnetic radiation, similar to an X-ray but of higher energy, that is emitted spontaneously by some radioactive substances (see gamma decay; radioactivity). Gamma radiation also originates in the decay of certain subatomic particles and in particle-antiparticle annihilation (seealso antimatter). Gamma rays can initiate nuclear fission, can be absorbed by ejection of an electron (see photoelectric effect), and can be scattered by free electrons (see Compton effect).

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Any of the aquatic rays (families Torpedinidae, Narkidae, and Temeridae) that produce an electrical shock. They are found worldwide in warm and temperate seas, mostly in shallow water but some (genus Benthobatis) at depths greater than 3,000 ft (900 m). Slow-moving bottom-dwellers, they feed on fishes and invertebrates. They range in length from less than 1 ft (30 cm) to about 6 ft (1.8 m) and have a short, stout tail. They are soft and smooth-skinned, with a circular or nearly circular body disk formed by the head and pectoral fins. They are harmless unless touched or stepped on. The electric organs, composed of modified muscle tissue, are in the disk near the head. The shock from these organs, which may reach 220 volts and is strong enough to fell a human adult, is used for defense, sensory location, and capturing prey.

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High-speed particle (atomic nucleus or electron) that travels through the Milky Way Galaxy. Some cosmic rays originate from the Sun, but most come from outside the solar system. Primary cosmic rays that reach Earth's atmosphere collide with nuclei in it, creating secondaries. Because lower-energy primaries are strongly influenced by the interplanetary magnetic field and Earth's magnetic field (see geomagnetic field), most of those detected near Earth have very high energy, corresponding to speeds about 87percnt that of light or more. Observations from spacecraft indicate that most cosmic rays come from the Galaxy's disk, but the highest-energy ones are probably extragalactic. Details of their production and acceleration remain unclear, but apparently expanding shock waves from supernovas can accelerate particles. From the early 1930s to the 1950s, cosmic rays were the only source of high-energy particles used in studying the atomic nucleus and its components. Short-lived subatomic particles were discovered through cosmic-ray collisions, leading to the rise of particle physics. Even powerful particle accelerators cannot impart energy anywhere near that of the highest-energy cosmic rays. Seealso Victor Francis Hess.

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Electronic display device used to produce patterns on a screen that are the graphical representations of electrical signals. Time is normally on the horizontal axis, and a function of the voltage generated by the input signal to the oscilloscope on the vertical axis; four or more plots can be simultaneously shown. Because almost any physical phenomenon can be converted into a corresponding electric voltage, oscilloscopes find commercial, engineering, and scientific applications in acoustic research, television-production engineering, and electronics design.

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Stream of electrons leaving the negative electrode, or cathode, in an evacuated or gas-filled discharge tube or emitted by a heated filament in certain electron tubes. Cathode rays cause fluorescent materials to luminesce and are utilized in cathode-ray oscilloscopes and television tubes (see cathode-ray tube).

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orig. Walker Smith, Jr.

(born May 3, 1921, Detroit, Mich., U.S.—died April 12, 1989, Culver City, Calif.) U.S. boxer. Robinson began boxing in high school in New York City and won all of his 89 amateur fights. He was six times a world champion, once (1946–51) as a welterweight (147 lbs) and five times (1951–60) as a middleweight (160 lbs). In 201 professional bouts, he made 109 knockouts. He suffered only 19 defeats, most when he was past 40. His outstanding ability and flamboyant personality made him a hero of boxing fans throughout the world, and he is sometimes considered the best fighter in history.

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(born May 2, 1921, Calcutta, India—died April 23, 1992, Calcutta) Bengali-Indian film director. After studying with Rabindranath Tagore, he became art director of an ad agency and a book illustrator. He sold all his possessions to make his first film, Pather Panchali (1955), a story of village life. With Aparajito (1956) and The World of Apu (1959), he completed the brilliant Apu Trilogy and brought Indian cinema to world attention. He later won acclaim for Devi (1960), Two Daughters (1961), The Big City (1964), The Lonely Wife (1964), The Chess Players (1977), The Home and the World (1984), and The Visitor (1990). He wrote all his own screenplays, noted for their humanism and poetry, and often composed the music for his films, though his short stories and novellas became his main source of income.

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orig. Emmanuel Radnitzky

(born Aug. 25, 1890, Philadelphia, Pa., U.S.—died Nov. 18, 1976, Paris, France) U.S. photographer, painter, and filmmaker. He grew up in New York City, where he studied architecture, engineering, and art. With Marcel Duchamp he formed the New York Dada group in 1917 and produced ready-mades. In 1921 he moved to Paris and became associated with the Surrealists. He rediscovered the technique for making “cameraless” pictures (photograms), which he called “rayographs,” by placing objects on light-sensitive paper; he also experimented with the technique of solarization, which renders part of the image negative and part positive by exposing a print or negative to a flash of light during development. He turned to portrait and fashion photography and made a virtually complete record of the celebrities of Parisian cultural life of the 1920s and '30s. He also made important contributions as an avant-garde filmmaker in the 1920s.

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(born Nov. 29, 1627, Black Notley, Essex, Eng.—died Jan. 17, 1705, Black Notley) British naturalist and botanist. He attended Cambridge University and spent many years there as a fellow. With Francis Willughby (1635–1672) he undertook a complete catalog of living things, of which he published numerous volumes. His enduring legacy to botany was the establishment of species as the ultimate unit of taxonomy. He attempted to base his systems of classification on all the structural characteristics of organisms, including internal anatomy, rather than on a single feature. By insisting on the importance of lungs and heart structure, he effectively established the class of mammals, and he divided insects according to the presence or absence of multiple metamorphoses. Coming closer to a truly natural system of taxonomy than had any of his contemporaries, Ray helped make possible Carolus Linnaeus's later contributions.

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(born Oct. 5, 1902, Chicago, Ill., U.S.—died Jan. 14, 1984, San Diego, Calif.) U.S. restaurateur, a pioneer of the fast-food industry. He was working as a blender salesman when he discovered a restaurant in San Bernardino, Calif., owned by Maurice and Richard McDonald, who used an assembly-line format to prepare and sell a large volume of hamburgers, french fries, and milk shakes. Beginning in 1955 Kroc opened his first McDonald's drive-in restaurant in Des Plaines, Ill., paying the brothers a percentage of the receipts. He soon began selling franchises for new restaurants, and he instituted a training program for owner-managers that emphasized automation and standardization. At the time of his death there were some 7,500 McDonald's restaurants worldwide; with more than 25,000 restaurants in the early 21st century, McDonald's was the world's largest food-service retailer.

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orig. Ray Charles Robinson

(born Sept. 23, 1930, Albany, Ga., U.S.—died June 10, 2004, Beverly Hills, Calif.) U.S. pianist, singer, and songwriter. His family moved to Greenville, Fla., where he began his musical career at age 5 in a neighbourhood café. By age 7 he had completely lost his sight. He learned to write scores in Braille. Orphaned at 15, he left school to play professionally. He recorded “Mess Around” and “It Should've Been Me” in 1952–53, and his arrangement for Guitar Slim's “The Things That I Used to Do” became a million-seller. Combining blues and gospel music influences, a distinctive raspy voice, and liquid phrasing, Charles later had hits with “What'd I Say,” “Georgia on My Mind,” and “Hit the Road, Jack.” His Modern Sounds in Country and Western Music (1962), marking unusual territory for a black performer, sold more than a million copies. He received 13 Grammy Awards, including a lifetime achievement award in 1987. Charles was inducted into the Rock and Roll Hall of Fame in 1986.

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(born Aug. 22, 1920, Waukegan, Ill., U.S.) U.S. author. Bradbury is best known for highly imaginative science-fiction stories and novels that blend social criticism with an awareness of the hazards of runaway technology. The Martian Chronicles (1950; television miniseries, 1980) is considered a science-fiction classic. His other short-story collections include The Illustrated Man (1951; film, 1969), The October Country (1955), I Sing the Body Electric! (1969; teleplay, 1981), and Quicker Than the Eye (1996). Among his novels are Fahrenheit 451 (1953; film, 1966); Dandelion Wine (1957; film, 1997) and its sequel, Farewell Summer (2006); and Death Is a Lonely Business (1985).

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