excretion Bodily process for disposing of undigested food waste prod¬ ucts and nitrogenous by-products of metabolism, regulating water content, maintaining acid-base balance, and controlling osmotic pressure to pro¬ mote homeostasis. It refers to both urination and defecation and to the pro¬ cesses that take place in the digestive and urinary systems, as the kidney and liver filter wastes, toxins, and drugs from the blood and food reaches the last stage of digestion. Ammonia from protein digestion, the primary excretory product, is converted to urea to be excreted in urine.
executive In politics, a person or persons constituting the branch of government charged with executing or carrying out the laws and appoint¬ ing officials, formulating and instituting foreign policy, and providing diplomatic representation. In the U.S., a system of checks and balances
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exegesis ► Explorer I 649
keeps the power of the executive more or less equal to that of the judi¬ ciary and the legislature. See also mayor, president, prime minister.
exegesis V.ek-so-'je-sos, 'ek-s3-je-sos\ Scholarly interpretation of reli¬ gious texts, using linguistic, historical, and other methods. In Judaism and Christianity, it has been used extensively in the study of the Bible. Textual criticism tries to establish the accuracy of biblical texts. Philological criti¬ cism deals with grammar, vocabulary, and style in pursuit of faithful translation. Literary criticism classifies texts according to style and attempts to establish authorship, date, and audience. Tradition criticism seeks the sources of biblical materials and traces their development. Redaction criticism examines the way pieces of the tradition have been assembled into a literary composition by editors. Form criticism studies the way narratives are shaped by the cultures that produce them. Histori¬ cal criticism looks at a text’s historical context.
Exekias \ek-'sek-yos\ (fl. c. 540-520 bc, Greece) Greek potter. He was the most famous of the black-figure vase painters (see black-figure pot¬ tery). His name is found on 13 surviving vases. He is known for his elegant drawing; his greatest gift was for conveying pathos and insight rather than overt action. Some 40 unsigned vases are attributed to him on stylistic grounds. He also made clay plaques designed to decorate tombs.
exercise Training of the body to improve health and fitness. Different types have different purposes, including aerobics for heart and respiratory function and weight loss, weight-bearing exercise for bone strength, weight training for muscle strength, and stretching for flexibility. Specific exercises are used in physical medicine and rehabilitation. Benefits include lower blood pressure, higher HDL cholesterol, improved disease resistance, and better general well-being.
Exeter \'ek-sa-tar\ ancient Isca Dumnoniorum City and adminis¬ trative district (pop., 2001: 111,078), administrative and historic county of Devon, England. The county town (seat) of Devon, it is located on the River Exe about 10 mi (16 km) above the English Channel and commands an important river crossing. An early British tribe, the Dumnonii, made Exeter their centre; when it was taken by the Romans, they named it Isca Dumnoniorum. The main town in southwestern England during the Middle Ages, Exeter was subjected to a number of sieges. Alfred the Great twice held it against the Danes (877 and c. 894); the Danes finally took the city in 1003 but lost it in 1068 to William I (the Conqueror). Exeter’s Norman cathedral, consecrated in 1133, houses the Exeter Book, the larg¬ est collection extant of Old English poetry. The city has light manufactur¬ ing and is a service centre for an extensive region.
existentialism Philosophical movement oriented toward two major themes, the analysis of human existence and the centrality of human choice. Existentialism’s chief theoretical energies are thus devoted to questions about ontology and decision. It traces its roots to the writings of Soren Kierkegaard and Friedrich Nietzsche. As a philosophy of human existence, existentialism found its best 20th-century exponent in Karl Jas¬ pers; as a philosophy of human decision, its foremost representative was Jean-Paul Sartre. Sartre finds the essence of human existence in freedom—in the duty of self-determination and the freedom of choice— and therefore spends much time describing the human tendency toward “bad faith,” reflected in humanity’s perverse attempts to deny its own responsibility and flee from the truth of its inescapable freedom.
Exmouth Gulf Inlet of the Indian Ocean, Western Australia. Located between North West Cape and the mainland, the gulf is 55 mi (90 km) long and 30 mi (48 km) across the mouth. Fishing, pearling, prawning, and tour¬ ism are the main local industries. Nearby Cape Range National Park is important for the conservation of the rare yellow-footed rock wallaby.
Exodus Second book of the Old Testament. The title refers to the depar¬ ture of the Israelites from Egypt under Moses in the 13th century bc. The book begins with the story of the Israelites’ enslavement in Egypt and God’s call to Moses to become a prophet. It tells of the plagues sent to persuade the pharaoh to free the Israelites, and it recalls their crossing of the Sea of Reeds (or the Red Sea) and their 40 years of wandering in the Sinai desert. It also recounts how God made a covenant with Israel at Mount Sinai, handing down the Ten Commandments. In Exodus God estab¬ lishes his reliability as Israel’s protector and savior, and lays claim to its loyalty and obedience.
exogamy and endogamy \ek-'sa-g3-me...en-'da-g9-me\ Practices controlling the relation of the sexes in the selection of marital partners. Exogamous groups require their members to marry outside the group,
sometimes even specifying the group into which members must marry. Such groups are usually defined in terms of kinship rather than politics or territory. Exogamy is usually characteristic of unilineal descent groups, in which descent is reckoned either patrilineally or matrilineally. In endoga- mous groups, marriage outside one’s group may be forbidden, or there may merely be a tendency to marry within the group. Endogamy is char¬ acteristic of aristocracies and religious and ethnic minorities in industri¬ alized societies but also of the caste system in India and of class-conscious nonliterate societies such as the Masai of East Africa.
exorcism In Christianity, a ceremony used to drive demons out of a per¬ son they have possessed. Jesus healed people tormented by evil spirits, casting them out with a word, and his followers later drove out demons “in his name.” By the 3rd century this task was assigned to a specially trained class of lower clergy. Rituals for exorcism of people and places also exist in many other traditions.
expanding universe Current understanding of the state of the uni¬ verse. It is based on the finding that all galaxies are moving away from each other. Application of general relativity to cosmology, along with the detection of redshifted light coming from galaxies outside the Milky Way Galaxy, led to the realization in the 1920s that all galaxies are receding (see Edwin Hubble). It is unknown whether the universe will expand indefi¬ nitely (open universe) or eventually collapse (closed universe) into an extremely dense, congested state, as it began, according to the big-bang model. See also Friedmann universe.
experimental psychology Branch or type of psychology concerned with employing empirical principles and procedures in the study of psy¬ chological phenomena. The experimental psychologist seeks to carry out tests under controlled conditions in order to discover an unknown effect or law, to examine or establish a hypothesis, or to illustrate a known law. The areas of study that rely most heavily on the experimental method include those of sensation and perception, learning and memory, motivation, and physiological psychology. Experimental approaches are also used in CHILD PSYCHOLOGY, CLINICAL PSYCHOLOGY, EDUCATIONAL PSYCHOLOGY, and SOCIAL PSY¬ CHOLOGY.