Ritalin A mild form of amphetamine used in the treatment of attention- deficit hyperactivity disorder (ADHD), generic name methylphenidate. Ritalin, taken as a pill, also has been effective for the treatment of other conditions such as narcolepsy. Although the drug acts as a stimulant in most people, Ritalin calms and focuses those with ADHD. Ritalin’s mode of action is unknown, but it is thought that the drug reduces symptoms by increasing the amount and activity of a neurotransmitter in the brain.
rite of passage See rite of passage
Ritsos Vret-s6s\, Yannis (b. May 1, 1909, Monemvasia, Greece—d. Nov. 11, 1990, Athens) Greek poet. He joined the Greek Communist Party in 1934, the year his first collection of poems, Tractors, appeared. It and a second collection mixed socialist philosophy with images of his per¬ sonal suffering. His third collection, Funeral Procession (1936), provided the words for the anthem of the Greek Left. He fought as a communist during the Nazi occupation and Greek civil war, and he spent four years in prison camps. Arrested and exiled in 1967, he was prohibited from publishing until 1972. Despite those obstacles, he wrote a total of 117 books, including plays and essays.
Rittenhouse, David (b. April 8, 1732, Germantown, Pa.—d. June 26, 1796, Philadelphia, Pa., U.S.) U.S. astronomer and inventor. He was a clockmaker by trade but also built mathematical instruments and, it is believed, the first telescope in the U.S. In 1769 he observed Venus mov¬ ing across the face of the Sun and noted that Venus has an atmosphere. Rittenhouse served as treasurer of Pennsylvania (1777-89), first director of the U.S. Mint in Philadelphia (1792-95), and president of the Ameri¬ can Philosophical Society (1791-96).
Rivadavia \ l re-va-tha-ve-o\ / Bernardino (b. May 20, 1780, Buenos Aires, Arg.—d. Sept. 2, 1845, Cadiz, Spain) First president of the Argen¬ tine republic (1826-27). Active in the 1810 movement for independence from Spain, he came to dominate the ruling revolutionary triumvirate in 1811. He disbanded the Spanish courts, abolished censorship, and ended the slave trade. Elected president of the United Provinces in 1826, he continued to advance reforms but was unable to extricate his country from a fruitless war with Brazil and was constantly embroiled with provincial caudillos. Unable to win acceptance for a centralist constitution, he resigned. His cultural initiatives, including the founding of the University of Buenos Aires, were among his greatest achievements. Most of his later years were spent in exile.
river Natural stream of water that flows in a channel with more or less defined banks. Rivers are a fundamental link in the hydrologic cycle, and they play a major role in shaping the surface features of the Earth. Even apparently arid desert regions are greatly influenced by river action when
periodic floodwaters surge down usually dry watercourses. River flow is sustained by the difference between water input and output. Rivers are fed by overland runoff, groundwater seepage, and meltwater released along the edges of snowfields and glaciers. Direct precipitation contrib¬ utes only very small amounts of water. Losses of river water result from percolation into porous and permeable rock, gravel, or sand; evaporation; and ultimately outflow into the ocean.
river blindness or onchocerciasis \ I aq-ko- 1 s3r-'kI-9-s9s\ Human disease caused by a filarial worm native to Africa but also found in parts of tropical America and transmitted by several blackflies. It is so called because the flies that transmit the disease breed on rivers and mostly affect riverine populations. Blindness is caused by dead microfilariae—the lar¬ vae that can be produced for some 15-18 years by adult worms—inside the eye. River blindness is common in savannah areas of Africa and in Guatemala and Mexico. In 1987 the World Health Organization began to distribute the drug ivermectin (originally developed for use against live¬ stock parasites), which eliminates the microfilariae, though it does not kill the adult parasite.
Rivera, Diego (b. Dec. 8, 1886, Guanajuato, Mex.—d. Nov. 25, 1957, Mexico City) Mexican muralist. After study in Mexico City and Spain, he settled in Paris from 1909 to 1919. He briefly espoused Cubism but abandoned it c. 1917 for a visual language of simplified forms and bold areas of colour. Returning to Mexico in 1921, he sought to create a new national art on revolutionary themes in the wake of the Mexican Revolu¬ tion. He painted many public murals, the most ambitious of which is in the National Palace (1929-57). From 1930 to 1934 he worked in the U.S. His mural for New York’s Rockefeller Center aroused a storm of contro¬ versy and was ultimately destroyed because it contained the figure of Vladimir Ilich Lenin; he later reproduced it at the Palace of Fine Arts in Mexico City. With Jose Clemente Orozco and David Alfaro Siqueiros, Riv¬ era created a revival of fresco painting that became Mexico’s most sig¬ nificant contribution to 20th-century art. His large-scale, didactic murals contain scenes of Mexican history, culture, and industry, with Indians, peasants, conquistadores, and factory workers drawn as simplified figures in crowded, shallow spaces. Rivera was married to Frida Kahlo almost uninterruptedly from 1929 to 1954.
Rivera, Jose Antonio Primo de See Jose Antonio Primo de Rivera Rivera, Luis Munoz See Luis Munoz Rivera
Rivers, Larry orig. Yitzroch Loiza Grossberg (b. Aug. 17, 1923, New York, N.Y., U.S.—d. Aug. 14, 2002, Southampton, N.Y.) U.S. painter associated with Abstract Expressionism and Pop art. He studied at the Juil- liard School in New York City and was a professional jazz saxophonist before turning to painting and studying with Hans Hofmann. His early works are characterized by frequent use of complex, fragmentary, and multiple views; perhaps the best-known is the harshly realistic Double Portrait of Berdie (1955). From the 1960s he introduced commercial images into his work, as well as elements of collage, construction, and sculpture; an elaborate example of his mixed-media works is The History of the Russian Revolution (1965).
Riverside City (pop., 2000: 255,166), southern California, U.S. It lies on the Santa Ana River. Along with San Bernardino and Ontario, Riverside forms a metropolitan complex east of Los Angeles. Settled in the 1870s, it was incorporated as a city in 1883 and became known for its citrus industry. Its economy now includes manufacturing and educational activities.
Riviera X.ri-ve-'er-sX Coastal region bordering the Mediterranean Sea in southeastern France, Monaco, and northwestern Italy. It extends from Cannes, France, to La Spezia, Italy. The Italian Riviera is divided into the Riviera di Ponente, west of Genoa, and the Riviera di Levante, east of Genoa. The French Riviera is also called the Cote d'Azur. Noted for its scenery and pleasant climate, it is one of the major tourist centres of Europe. Because of its mild winters, many delicate plants flourish there, and flowers are grown out of season for export to northern markets. See also Cannes; Nice; Monte Carlo.
Riyadh \re-‘yad\ City (pop., 2004: 4,087,152), capital of Saudi Arabia. Located in the east-central part of the country, it was chosen as the capi¬ tal of the Sa'ud dynasty in 1824. It remained the centre of Sa'udI rule until 1881, when the Rashid family took control of the region. In 1902 Ibn Sa'Gd regained control, and it became the centre for his conquest of the Ara¬ bian Peninsula. When the kingdom of Saudi Arabia was proclaimed in 1932, Riyadh became the capital. Discovery of immense petroleum depos-
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1626 I Rizal ► Roanoke Island
its in the kingdom in the 1930s transformed the old provincial town into a showplace of sophisticated technology, modern architecture, and high¬ ways. In addition to its administrative role, Riyadh is the kingdom’s com¬ mercial, education, and transportation centre.
Rizal (y Alonso) \re-'sal\, Jose in full Jose Protasio Rizal Mer¬ cado y Alonso Realonda (b. June 19,1861, Calamba, Phil.—d. Dec. 30, 1896, Manila) Filipino patriot, physician, and man of letters. Begin¬ ning in his youth, Rizal committed himself to the reform of Spanish rule in his home country. He lived in Europe (1882-92), where he published novels exposing the evils of Spanish rule and became the leader of the Propaganda movement, which produced reform-oriented articles, maga¬ zines, and poetry. He returned to the Philippines to found a nonviolent- reform society and was deported to Mindanao, where he spent four years. When the Katipunan nationalist secret society revolted in 1896, the Span¬ ish arrested and executed Rizal, though he had no connection with the group and had taken no part in the insurrection. His martyrdom convinced Filipinos that there was no alternative to independence from Spain.