Mongolia: The arts: …journalist Tsendiin Damdinsüren and poet Ochirbatyn Dashbalbar. Damdinsüren (1908–88), a translator of Russian novels and also at one time accused of “bourgeois nationalism,” wrote the words of the Mongolian national anthem and produced a three-volume commentary on Mongolian literature. Dashbalbar (1957–99), who attended and graduated from a literary institute in…

taro, (Colocasia esculenta), herbaceous plant of the arum family (Araceae) and its edible rootlike corm. Taro is probably native to southeastern Asia, whence it spread to Pacific islands and became a staple crop. It is cultivated for its large, starchy, spherical corms (underground stems), commonly

Nantong: In 1895 he founded the Dah Sun Cotton Mill (Dasheng Sha Chang) at Tangzha, some 5.5 miles (9 km) west of Nantong. This mill came into production in 1899 and proved more efficient than any other private textile firm of the same period. Out of its profits, Zhang, between 1900…

Dussehra, in Hinduism, holiday marking the triumph of Rama, an avatar of Vishnu, over the 10-headed demon king Ravana, who abducted Rama’s wife, Sita. The festival’s name is derived from the Sanskrit words dasha (“ten”) and hara (“defeat”). Symbolizing the victory of good over evil, Dussehra is

Daşoguz, city, northern Turkmenistan. It is located in the western Khorezm (Khwārezm) oasis. The Shavat Canal, which gets its water from the nearby Amu Darya (ancient Oxus River), divides the city into northern and southern sections. Originally a fort and the bazaar of the western Khwārezm region,

Diane Johnson: …Lives (1972), and the biography Dashiell Hammett: A Life (1983). She also wrote screenplays, including The Shining (1980; with Stanley Kubrick); a collection of essays, Terrorists and Novelists (1982); and Into a Paris Quartier (2005), about Paris’s Saint-Germain-des-Prés neighbourhood. The memoir Flyover Lives was published in 2014.

Shanghai: Cultural life: The Dashijie (“Great World”), founded in the 1920s, is Shanghai’s leading theatrical centre and offers folk operas, dance performances, plays, story readings, and specialized entertainment forms typical of China’s national minority groups. The city also has many workers’ and children’s recreational clubs and several large motion-picture…

Yekaterina Romanovna Vorontsova, Princess Dashkova was an associate of Empress Catherine II the Great and a prominent patroness of the literary arts in 18th-century Russia. A member of the influential Vorontsov family, Yekaterina Romanovna married Prince Mikhail Ivanovich Dashkov in 1759. After

Armenia: Armenia and Europe: …1887 and the more nationalist Dashnaktsutyun (“Confederacy”) party, whose members were commonly called Dashnaks, in 1890, and, in the face of increasing Armenian demands for much-needed reforms, both the Ottoman and Russian governments grew more repressive. In 1895, after Abdülhamid II had felt compelled to promise Britain, France, and Russia…

Armenia: Armenia and Europe: …1887 and the more nationalist Dashnaktsutyun (“Confederacy”) party, whose members were commonly called Dashnaks, in 1890, and, in the face of increasing Armenian demands for much-needed reforms, both the Ottoman and Russian governments grew more repressive. In 1895, after Abdülhamid II had felt compelled to promise Britain, France, and Russia…

dashnami sannyasin, Hindu Shaivite ascetic who belongs to one of the 10 orders (dashnami, “ten names”) established by the philosopher Shankara in the 8th century ce and still flourishing in India today. The 10 orders are Aranya, Ashrama, Bharati, Giri, Parvata, Puri, Sarasvati, Sagara, Tirtha, and

Lūt Desert, desert in eastern Iran. It stretches about 200 miles (320 km) from northwest to southeast and is about 100 miles (160 km) wide. In the east rises a great massif of dunes and sand, while in the west an extensive area of high ridges is separated by wind-swept corridors. In its lowest,

Lūt Desert, desert in eastern Iran. It stretches about 200 miles (320 km) from northwest to southeast and is about 100 miles (160 km) wide. In the east rises a great massif of dunes and sand, while in the west an extensive area of high ridges is separated by wind-swept corridors. In its lowest,

Zhang Zuolin was a Chinese soldier and later a warlord who dominated Manchuria (now Northeast China) and parts of North China between 1913 and 1928. He maintained his power with the tacit support of the Japanese; in return he granted them concessions in Manchuria. Born into a peasant family, Zhang

Dashwood family, featured characters in Jane Austen’s novel Sense and Sensibility (1811). The widowed Mrs. Dashwood and her three daughters—Elinor, Marianne, and Margaret—are impoverished by the death of Mr. Dashwood and by the selfishness and neglect of his heir, who is his son by his first wife.

bharata natyam, the principal of the main classical dance styles of India, the others being kuchipudi, kathak, kathakali, manipuri, and odissi. It is indigenous to the Tamil Nadu region and prevalent in southern India. Bharata natyam serves the expression of Hindu religious themes and devotions,

cinquefoil: The genus Dasiphora, known as shrubby cinquefoils, is closely related to Potentilla and consists of three species of shrubs with pinnately compound leaves and five-petaled flowers. D. fruticosa (formerly P. fruticosa) has provided many dwarf shrubs used in landscaping.

cinquefoil: D. fruticosa (formerly P. fruticosa) has provided many dwarf shrubs used in landscaping.

Daşoguz, city, northern Turkmenistan. It is located in the western Khorezm (Khwārezm) oasis. The Shavat Canal, which gets its water from the nearby Amu Darya (ancient Oxus River), divides the city into northern and southern sections. Originally a fort and the bazaar of the western Khwārezm region,

Petter Dass was a Norwegian poet who, in an age of pedantry and artifice, stands out among his contemporaries for the vivid freshness, everyday language, and common appeal of his works. He is the first writer in Dano-Norwegian literature to strike a genuinely Norwegian note. The son of a Scottish

Dassault Industries: …of World War II, is Dassault Aviation, which adopted its current name in 1990. Headquarters are in Vaucresson, France.

Dassault Industries, French company with major aerospace-related subsidiaries specializing in the production of military and civil aircraft; computer-based design, manufacturing, and product-management systems; and aviation simulators. Its primary subsidiary, founded by French aircraft designer

Marcel Dassault was a French aircraft designer and industrialist whose companies built the most successful military aircraft in Europe in the decades after World War II. The son of a Jewish physician, Bloch obtained degrees in aeronautical design and electrical engineering and worked as an aircraft

Rainald Of Dassel was a German statesman, chancellor of the Holy Roman Empire, and archbishop of Cologne, the chief executor of the policies of the emperor Frederick I Barbarossa in Italy. After studying at Hildesheim and Paris and serving as a church provost, Rainald became (1153) a member of

Dussehra, in Hinduism, holiday marking the triumph of Rama, an avatar of Vishnu, over the 10-headed demon king Ravana, who abducted Rama’s wife, Sita. The festival’s name is derived from the Sanskrit words dasha (“ten”) and hara (“defeat”). Symbolizing the victory of good over evil, Dussehra is

hyrax, (order Hyracoidea), any of six species of small hoofed mammals (ungulates) native to Africa and extreme southwestern Asia. Hyraxes and pikas are sometimes called conies or rock rabbits, but the terms are misleading, as hyraxes are neither lagomorphs nor exclusively rock dwellers. The term

dassie rat, (Petromus typicus), a medium-sized rodent adapted to life among rocky outcrops in the desert hills and plateaus of southwestern Africa. The dassie rat weighs 170 to 300 grams (6 to 11 ounces) and has a squirrel-like body 14 to 21 cm (5.5 to 8.3 inches) long; its hairy tail is 12 to 17

Jules Dassin was an American director who was a master of film noir and perhaps best remembered for Rififi (1955), one of the most influential heist movies. Dassin was born in the United States but studied drama in Europe. He joined the Yiddish Theatre in New York in 1936, then wrote radio scripts

Jules Dassin was an American director who was a master of film noir and perhaps best remembered for Rififi (1955), one of the most influential heist movies. Dassin was born in the United States but studied drama in Europe. He joined the Yiddish Theatre in New York in 1936, then wrote radio scripts

Khosrow II: Expansion of the empire: …by Heraclius’ brave dash to Dastagird, the royal residence 70 miles (113 kilometres) north of Ctesiphon. An important but indecisive battle was fought near Nineveh, but, as the Byzantine army reapproached Dastagird, Khosrow fled. His letters calling Shahrbarāz to his aid had been intercepted, and, although his resources were by…

dastak, in 18th-century Bengal, a permit exempting European traders, mostly of the British East India Company, from paying customs or transit duties on their private trade. The name came from the Persian word for “pass.” The practice was introduced by Robert Clive, one of the creators of British

Khwāja ʿAbd-uṣ-Ṣamad: …of the illustrations of the Dāstān-e (“Stories of”) Amīr Ḥamzeh, a series that numbered about 1,400 paintings, all of unusually large size. As none of the paintings is signed, it is not certain whether he himself did any of them. Among the miniatures bearing his signature is one in the…

dastgāh, any of the principal modes of the art music of Persian-speaking areas, used as the basis for composition and improvisation. A dastgāh incorporates a scale, a motif, a group of short pieces, and a recognizable identity. The scale (maqām) is a collection of seven pitches, some of which may

Zoroastrianism: Priesthood: …of these functionaries is the dastūr, a kind of bishop, who directs and administers one or more important temples. Priesthood is hereditary, but all priests have to go through one or more ceremonies of investiture over and above those practiced by all the faithful.

Dasvant was a leading Indian Mughal artist, cited by Abu al-Faḍl ʿAllāmī, the historiographer of the emperor Akbar’s court, as having surpassed all painters to become “the first master of the age.” Little is known of his life, though it is conjectured that he was a Hindu, probably of humble origin.

Dasam Granth, collection of writings attributed to Gurū Gobind Singh, the tenth and last spiritual leader of the Sikhs, a religious group in India. Dasam Granth is a short title for Dasven Pādśāh kā Graṅth (Punjabi: “The Book of the Tenth Emperor [i.e., spiritual leader]”). It is a compilation of

whip-tailed ray, any of certain stingrays of the family Dasyatidae. See

stingray: …(10 inches), but the Australian D. brevicaudata reportedly attains a width of about 2 metres (7 feet) and a length of 4 metres. The urolophid, or round stingrays, are considerably smaller, the largest attaining a length of about 75 cm. Round stingrays have relatively short tails and well-developed tail fins.…

stingray: They vary in size: Dasyatis sabina, a small western North Atlantic species, is mature at a width of about 25 cm (10 inches), but the Australian D. brevicaudata reportedly attains a width of about 2 metres (7 feet) and a length of 4 metres. The urolophid, or round stingrays,…

marsupial mouse: The crest-tailed marsupial mouse, or mulgara (Dasycercus cristicauda), an arid-land species valued for killing house mice, gets all of its water from the bodies of its prey.

apterygote: Evolution and paleontology: …years ago) of France and D. brongniarti of the Siberian Permian (299 million to 252 million years ago) deposits. The extinct family Triassomachilidae (order Archaeognatha) includes Triassomachilis uralensis of the Triassic (252 million to 201 million years ago) deposits of Russia. Other extinct species occur in the genera Machilis, Praemachilis,…

apterygote: Evolution and paleontology: …order Monura includes two species, Dasyleptus lucasi of the Late Carboniferous (323 million to 299 million years ago) of France and D. brongniarti of the Siberian Permian (299 million to 252 million years ago) deposits. The extinct family Triassomachilidae (order Archaeognatha) includes Triassomachilis uralensis of the Triassic (252 million to…

gall midge: The rose midge (Dasyneura rhodophaga) infests the young buds and shoots of roses and is a serious pest in greenhouses but rarely outside. Some other serious pests are the wheat midge, sorghum midge, rice midge, clover midge, and pear midge. Tobacco fumigation and dust on soil…

egg-eating snake, any of the five species of the genus Dasypeltis of sub-Saharan Africa and Elachistodon westermanni of northeastern India. These nonvenomous snakes comprise the subfamily Dasypeltinae, family Colubridae. Members of Dasypeltis eat only bird eggs; E. westermanni sometimes consume the

armadillo, (family Dasypodidae), any of various armoured mammals found mainly in tropical and subtropical regions of Central and South America. Most of the 20 species inhabit open areas, such as grasslands, but some also live in forests. All armadillos possess a set of plates called the carapace

Arecales: Classification: The Australian family Dasypogonaceae (also known as Calectasiacea), with four genera and 16 species, was traditionally allied with the family Liliaceae (lilies) but is now believed to be more closely related to the palms because of their common possession of ultraviolet-fluorescent compounds in the cell walls, a special…

agouti, (genus Dasyprocta), any of about a dozen species of tropical American rodents resembling the small forest-dwelling hoofed animals of tropical Africa and Asia (see chevrotain; duiker; royal antelope). Agoutis weigh up to 6 kg (13 pounds), with an elongated body measuring up to 76 cm (2.5

agouti: …lowland and montane tropical rainforests, Azara’s agouti (Dasyprocta azarae) also inhabits the drier cerrado (savanna and scrub) and chaco environments south of the Amazon basin into Paraguay and northeastern Argentina. Three different agoutis have been introduced into the West Indies, presumably by native Caribbean tribes: D. mexicana in Cuba, D.…

agouti: leporina, the Brazilian agouti, in the Virgin Islands and the Lesser Antilles.

agouti: …presumably by native Caribbean tribes: D. mexicana in Cuba, D. punctata in Cuba and the Cayman Islands, and D. leporina, the Brazilian agouti, in the Virgin Islands and the Lesser Antilles.

agouti: mexicana in Cuba, D. punctata in Cuba and the Cayman Islands, and D. leporina, the Brazilian agouti, in the Virgin Islands and the Lesser Antilles.

paca: …are agoutis and acouchys (family Dasyproctidae). Both families belong to the suborder Hystricognatha, which includes guinea pigs and chinchillas. No paca fossils have been discovered.

armadillo: Classification and paleontology: Dasypodinae Genus Dasypus (long-nosed armadillos) Six species, including the nine-banded armadillo, D. novemcinctus. One Peruvian species found in the Andes Mountains has dense hair covering the carapace. Subfamily Euphractinae Genus Chaetophractus (hairy armadillos or peludos)

armadillo: Natural history: The mulita (D. hybridus) repeatedly utters a guttural monosyllabic sound similar to the rapid fluttering of a human tongue.

armadillo: The three-, six-, and nine-banded armadillos are named for the number of movable bands in their armour. Only one species, the nine-banded armadillo (Dasypus novemcinctus), is found in the United States. Its range has expanded into several southern states since it was first observed in Texas during the 1800s.…

dasyu, an aboriginal people in India who were encountered by the Indo-European-speaking peoples who entered northern India about 1500 bce. They were described by the Indo-Europeans as a dark-skinned, harsh-spoken people who worshipped the phallus. Some Western scholars who view the lingam (a Hindu

dasyurid, any member of a family (Dasyuridae) of marsupial mammals that includes the quolls (formerly called “native cats”), antechinus and dunnarts (formerly known as “marsupial mice and rats”), Tasmanian Devil, and their allies. All of the approximately 60 species occur in New Guinea, the Aru

dasyurid, any member of a family (Dasyuridae) of marsupial mammals that includes the quolls (formerly called “native cats”), antechinus and dunnarts (formerly known as “marsupial mice and rats”), Tasmanian Devil, and their allies. All of the approximately 60 species occur in New Guinea, the Aru

crest-tailed marsupial rat, (Dasyuroides byrnei), rare ratlike mammal of the family Dasyuridae (order Marsupialia), native to the desert and grasslands of central Australia. It averages about 17.5 cm (7 inches) in length, with about a 13.5-centimetre (5-inch) tail. The soft dense fur is a light

marsupial: Classification: Order Dasyuromorphia (carnivorous marsupials) 60 or so species in 2 families, not including the extinct Tasmanian wolf, or thylacine, sole member of family Thylacinidae. Family Dasyuridae (antechinus, dunnarts, dasyures, dibblers, kowari, marsupial mice,

native cat, any of the catlike Australian marsupials that make up the genus Dasyurus in the family Dasyuridae. All native cats are predators that hunt chiefly at night. Because they sometimes raid poultry yards, native cats have been persecuted and in some regions are extinct. Also contributing to

native cat: …generally smaller, as is the New Guinea native cat (D. albopunctatus), which occupies a variety of habitats on its native island. The largest species, the spotted-tailed native cat (D. maculatus, also called the tiger cat), has a length of 75 to 130 cm, including its 35- to 55-cm tail. This…

native cat: The western native cat (D. geoffroii) of the savannahs of southwestern and central Australia is almost the same size but has a relatively longer tail. The northern native cat (D. hallucatus) of tropical regions is generally smaller, as is the New Guinea native cat (D. albopunctatus),…

native cat: The northern native cat (D. hallucatus) of tropical regions is generally smaller, as is the New Guinea native cat (D. albopunctatus), which occupies a variety of habitats on its native island. The largest species, the spotted-tailed native cat (D. maculatus, also called the tiger cat), has…

native cat: The largest species, the spotted-tailed native cat (D. maculatus, also called the tiger cat), has a length of 75 to 130 cm, including its 35- to 55-cm tail. This species occurs in the dense, moist forests of Tasmania and eastern Australia.

native cat: The eastern native cat (D. viverrinus, or D. quoll), surviving chiefly in the forests and open country of Tasmania, is 55 to 75 centimetres (22 to 30 inches) long, including its 20- to 30-cm tail. The western native cat (D. geoffroii) of the savannahs of southwestern…

native cat: The eastern native cat (D. viverrinus, or D. quoll), surviving chiefly in the forests and open country of Tasmania, is 55 to 75 centimetres (22 to 30 inches) long, including its 20- to 30-cm tail. The western native cat (D. geoffroii) of the savannahs of southwestern…

Ignacy Daszyński was a Polish socialist leader and patriot who was prominent in the restoration of the Polish Republic after World War I. In October 1892 Daszyński was one of the organizers of the Polish Social Democratic Party in Galicia. He was elected to the Austrian Reichsrat in 1897 and was a

digital sound recording: In the late 1980s digital audio tape (DAT) recorders using magnetic tape cassettes became available for audio reproduction and recording. The DAT recorder converts audio signals into digital data on a magnetic tape by means of a microprocessor and converts the data back into analog audio signals that can…

aptitude test: The Differential Aptitude Test (DAT) measures specific abilities such as clerical speed and mechanical reasoning as well as general academic ability.

Bono: …eventually helped found in 2002 Debt, AIDS, Trade, Africa (DATA), a policy and advocacy organization that seeks to eradicate poverty, hunger, and the spread of AIDS in Africa through public awareness campaigns and in-country partnerships. That year he appeared on the cover of Time magazine with the legend “Can Bono…

principles of physical science: Compilation of data: Technical design, whether of laboratory instruments or for industry and commerce, depends on knowledge of the properties of materials (density, strength, electrical conductivity, etc.), some of which can only be found by very elaborate experiments (e.g., those dealing with the masses and excited states…

Euclid: Other writings: …the first group is the Data (from the first Greek word in the book, dedomena [“given”]), a disparate collection of 94 advanced geometric propositions that all take the following form: given some item or property, then other items or properties are also “given”—that is, they can be determined. Some of…

information processing: Recording techniques: …is commonly referred to as data, and its analog counterpart is called source data. Vast quantities of nondocument analog data are collected, digitized, and compressed automatically by means of appropriate instruments in fields such as astronomy, environmental monitoring, scientific experimentation and modeling, and national security. The capture of information generated…

data analysis, the process of systematically collecting, cleaning, transforming, describing, modeling, and interpreting data, generally employing statistical techniques. Data analysis is an important part of both scientific research and business, where demand has grown in recent years for

database, any collection of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval, modification, and deletion of data in conjunction with various data-processing operations. A database management

cloud computing: Data centres and privacy: Construction of the large data centres that run cloud-computing services often requires investments of hundreds of millions of dollars. The centres typically contain thousands of server computers networked together into parallel-processing or grid-computing systems. The centres also often employ sophisticated virtualization…

sociology: Data collection: Research techniques vary depending on the social phenomena studied. Data-collection techniques differ from participant observation, content analysis, interviewing, and documentary analysis. In this approach each problem studied requires a specific unit of observation, be it an individual, an organization, a city, a relationship…

data compression, the process of reducing the amount of data needed for the storage or transmission of a given piece of information, typically by the use of encoding techniques. Compression predates digital technology, having been used in Morse Code, which assigned the shortest codes to the most

data compression, the process of reducing the amount of data needed for the storage or transmission of a given piece of information, typically by the use of encoding techniques. Compression predates digital technology, having been used in Morse Code, which assigned the shortest codes to the most

endangered species: IUCN Red List of Threatened Species: …and abundant after careful assessment Data Deficient (DD), a condition applied to species in which the amount of available data related to its risk of extinction is lacking in some way. Consequently, a complete assessment cannot be performed. Thus, unlike the other categories in this list, this category does not…

computer science: Programming languages: …the addition of support for data encapsulation, which gave rise to object-oriented languages. The original object-oriented language was called Smalltalk, in which all programs were represented as collections of objects communicating with each other via message-passing. An object is a set of data together with the methods (functions) that can…

data encryption, the process of disguising information as “ciphertext,” or data unintelligible to an unauthorized person. Conversely, decryption, or decipherment, is the process of converting ciphertext back into its original format. Manual encryption has been used since Roman times, but the term

Data Encryption Standard (DES), an early data encryption standard endorsed by the U.S. National Bureau of Standards (NBS; now the National Institute of Standards and Technology). It was phased out at the start of the 21st century by a more secure encryption standard, known as the Advanced

virtual reality: Entertainment: …the iconic significance of the data glove in the emergence of VR in commerce and popular culture. Data gloves relay a user’s hand and finger movements to a VR system, which then translates the wearer’s gestures into manipulations of virtual objects. The first data glove, developed in 1977 at the…

computer science: Information management: Data integrity refers to designing a DBMS that ensures the correctness and stability of its data across all applications that access the system. When a database is designed, integrity checking is enabled by specifying the data type of each column in the table. For example,…

data mining, in computer science, the process of discovering interesting and useful patterns and relationships in large volumes of data. The field combines tools from statistics and artificial intelligence (such as neural networks and machine learning) with database management to analyze large

data processing, manipulation of data by a computer. It includes the conversion of raw data to machine-readable form, flow of data through the CPU and memory to output devices, and formatting or transformation of output. Any use of computers to perform defined operations on data can be included

Megaupload, popular file-sharing computer service created by entrepreneur Kim Schmitz that was shut down in 2012 by the United States government after its founders were charged for violating antipiracy laws. It was based in Hong Kong. In 2003 Schmitz, a native of Germany, moved to Hong Kong and

data protection, species of privacy law that controls access to information relating to the individual. Typically, data protection provides individuals with the right to see data held about themselves and to require correction. Beyond that, data protection determines how organizations holding data

information processing: Information searching and retrieval: State-of-the-art approaches to retrieving information employ two generic techniques: (1) matching words in the query against the database index (key-word searching) and (2) traversing the database with the aid of hypertext or hypermedia links.

data mining: …large digital collections, known as data sets. Data mining is widely used in business (insurance, banking, retail), science research (astronomy, medicine), and government security (detection of criminals and terrorists).

data structure, way in which data are stored for efficient search and retrieval. Different data structures are suited for different problems. Some data structures are useful for simple general problems, such as retrieving data that has been stored with a specific identifier. For example, an online

data transmission, sending and receiving data via cables (e.g., telephone lines or fibre optics) or wireless systems. Because ordinary telephone circuits pass signals that fall within the frequency range of voice communication (about 300–3,500 hertz), the high frequencies associated with data

computer: Internet and collaborative software: …information has given rise to data warehousing and data mining. The former is a term for unstructured collections of data and the latter a term for its analysis. Data mining uses statistics and other mathematical tools to find patterns of information. For more information concerning business on the Internet, see…

ancient Iran: The organization and achievement of the Achaemenian Empire: …called by the Iranian word dāta-bar. These were probably the judges of the imperial courts.

information system: Decision support systems and business intelligence: The primary objective of data-driven business intelligence systems is to analyze large pools of data, accumulated over long periods of time in data warehouses, in a process known as data mining. Data mining aims to discover significant patterns, such as sequences (buying a new house, followed by a new…

computer science: Networking and communication: The data-link layer handles standard-sized “packets” of data and adds reliability in the form of error detection and flow control bits. The network and transport layers break messages into the standard-size packets and route them to their destinations. The session layer supports interactions between applications on…

computer science: Networking and communication: The data-link layer handles standard-sized “packets” of data and adds reliability in the form of error detection and flow control bits. The network and transport layers break messages into the standard-size packets and route them to their destinations. The session layer supports interactions between applications on…

database, any collection of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval, modification, and deletion of data in conjunction with various data-processing operations. A database management