delirium Condition of disorientation, confused thinking, and rapid alter¬ nation between mental states. The patient is restless, cannot concentrate, and undergoes emotional changes (e.g., anxiety, apathy, euphoria), some¬ times with hallucinations. Delirium usually results from a disorder affect¬ ing the brain such as central nervous system infection, head trauma, or mental disorder. In severe cases of withdrawal from alcohol, delirium tre¬ mens results not from the excessive alcohol consumption alone but from exhaustion, malnutrition (particularly lack of thiamine), and dehydration.
delirium tremens \di-Tir-e-3m-'tre-menz\ (DTs) Delirium seen in severe cases of alcohol withdrawal (see alcoholism) complicated by exhaustion, lack of food, and dehydration, usually preceded by physical deterioration due to vomiting and restlessness. The whole body trembles, sometimes with seizures, disorientation, and hallucinations. Delirium tre¬ mens lasts 3-10 days, with a reported death rate of up to 20%. Halluci¬ nations may develop independently of delirium tremens and may last days to weeks.
Delius \'de-le-3s\, Frederick (Theodore Albert) (b. Jan. 29, 1862, Bradford, Yorkshire, Eng.—d. June 10, 1934, Grez-sur-Loing, France) British-born French composer. Bom to German parents in England, he studied music in Leipzig and elsewhere, and in 1887 Edvard Grieg con¬ vinced his parents to let him pursue a musical career. He moved to France, eventually settling in a village near Paris. After World War I he gradually succumbed to paralysis and blindness, the consequence of syphilis. His works, influenced by Claude Debussy, include the operas A Village Romeo and Juliet (1901) and Fennimore and Gerda (1910); the tone poems Brigg Fair (1907) and On Hearing the First Cuckoo in Spring (1912); and the choral works Appalachia (1903) and A Mass of Life (1908).
delivery See parturition
Della Robbia family \,dal-la-'r6b-y3\ Family of Italian artists active in Florence. The first works of Luca (di Simone di Marco) Della Robbia (1399/1400-1482) were reliefs sculptured in marble, most notably those for the Cantoria (singing-gallery) of Florence Cathedral (1432-37). He is remembered mainly for his development of glazed terra-cotta as a medium for sculpture; his major terra-cotta works include roundels of the Apostles (c. 1444) in Filippo Brunelleschi’s Pazzi Chapel in Santa Croce. In time the Della Robbia studio became a potters’ workshop-industry, famous espe¬ cially for its renderings of the Madonna and Child in white enamel on a
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530 I dell'Abbate ► Demiurge
blue ground. Andrea (di Marco) Della Robbia (1435-1525), Luca’s nephew, assumed control of the workshop c. 1470. Trained as a marble sculptor, his best-known works are ten roundels of infants on the facade of Florence’s Foundling Hospital (c. 1487). Giovanni Della Robbia (1469-1529), the most distinguished of Andrea’s sons, took control of the family workshop after his father’s death. His early works, notably a lavabo in Santa Maria Novella (1497) and medallions in the Loggia of San Paolo (1493-95), were collaborations with his father.
dell'Abbate, Niccolo See Niccolo dell’ABBATE
Delmarva Peninsula Peninsula, eastern U.S. Extending between Chesapeake and Delaware bays, it is about 180 mi (290 km) long and up to 70 mi (110 km) wide. Encompassing parts of the states of Delaware, Maryland, and Virginia—hence its name—it includes Maryland’s Eastern Shore. Fishing and tourism are economically important to the area.
Delors \da-T6r\, Jacques (Lucien Jean) (b. July 20, 1925, Paris, Fr.) French statesman. In 1962 he left his position in banking for a series of government positions, including minister of economics and finance. As president of the European Commission (EC) from 1985 to 1995, he pushed through reforms and persuaded the member states to agree to the creation of a single market in 1993, the first step toward full economic and political integration in the European Union. When his term expired, he was considered a leading contender for the French presidency, but he declined to run.
Delos Vde-,las\ Greek Dhilos Vthe-.losX Island, Greece. One of the smallest of the Cyclades, it was an ancient centre of religious, political, and commercial life in the Aegean. It was the legendary birthplace of Apollo and Artemis. The Delian League was established there in 478 bc, following the Persian Wars. Made a free port by Rome in 166 bc, Delos was a flourishing commercial post and slave market. Sacked in 88 bc dur¬ ing the Mithradatic Wars, it gradually declined and was abandoned. Its impressive ruins have been extensively excavated.
Delphi \'del-,fi\ Site of the ancient temple and oracle of Apollo in Greece. Located on the slopes of Mount Parnassus, it was the centre of the world in ancient Greek religion. According to legend, the oracle was originally sacred to Gaea, and Apollo acquired it by slaying her child, the serpent Python. From 582 bc Delphi was the site of the Pythian Games. The oracle was consulted not only on private matters but also on affairs of state, such as the founding of new colonies.
delphinium See larkspur
delta Low-lying plain composed of stream-borne sediments deposited by a river at its mouth. Deltas have been important to humankind since prehistoric times. Sands, silts, and clays deposited by floodwaters were extremely productive agriculturally; and major civilizations flourished in the deltaic plains of the Nile and Tigris-Euphrates rivers. In recent years geologists have discovered that much of the world’s petroleum resources are found in ancient deltaic rocks. Deltas vary widely in size, structure, composition, and origin, though many are triangular (the shape of the Greek letter delta).
dema deity \'da-ms \ Any of several mythical ancestral beings of the Marind-Anim people of southern New Guinea. In their mythology, the killing of a divine ancestor (a dema deity) brings about the transition from the ancestral world to the human one. In Ceramese mythology, for example, the goddess Hainuwele grows from a coconut blossom and is dismembered by dema men; when the pieces of her body are buried, they become new plant species, especially tubers, the chief food of the Cer¬ amese. Such myths offer explanations for the origin of agriculture as well as for human sexuality and death.
deme \'dem\ Greek demos In ancient Greece, a country district or vil¬ lage, as distinct from a pous. In the democratic reforms (508-507 bc) pro¬ moted by Cleisthenes, the demes of Attica (the area around Athens) gained a voice in local and state government. The Attic demes had their own police powers, cults, and officials. Males aged 18 years became registered members of the deme. Members decided deme matters and kept property records for taxation. Each deme sent representatives to the Athenian boule in proportion to its size. The term continued to be applied to local dis¬ tricts in Hellenistic and Roman times.
dementia \di-'men-shs\ Chronic, usually progressive deterioration of intellectual functions. Most common in the elderly, it usually begins with short-term-memory loss once thought a normal result of aging but now
known to result from Alzheimer disease. Other common causes are Pick disease and vascular disease. Dementia also occurs in Huntington chorea, paresis (see paralysis), and some types of encephalitis. Treatable causes include hypothyroidism (see thyroid gland), other metabolic diseases, and some malignant tumours. Treatment may arrest dementia’s progress but usually does not reverse it.