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“Discus Thrower” (statue by Myron)
...for his many studies of athletes in action. Of his many works, only two representations positively survive: the group of Athena and Marsyas, originally standing on the Acropolis of Athens, and the “Discobolos” (“Discus Thrower”), both in marble copies made in Roman times....
discusfish
two species of the genus Symphysodon of fishes in the family Cichlidae (order Perciformes), characterized by a compressed, disk-shaped body. The two species (S. discus and S. aequifasciata) occur naturally in tributaries of the Amazon River in South Am...
Discussion Between the Christian and the Pagan, The (work by Gqoba)
Fame came to Gqoba after the composition of his two long didactic poems, “The Discussion Between the Christian and the Pagan” and “The Great Discussion on Education,” both influenced in style by his fellow South African Tiyo Soga’s translation of Pilgrim’s Progress into Xhosa. In the first poem the traditional conflict is set up between the pleasure...
Discussion of Heaven, A (essay by Xunzi)
Another celebrated essay is “A Discussion of Heaven,” in which he attacks superstitious and supernatural beliefs. One of the work’s main themes is that unusual natural phenomena (eclipses, etc.) are no less natural for their irregularity—hence are not evil omens—and therefore men should not be concerned at their occurrence. Xunzi’s denial of supernaturalis...
Discussion of Music, A (essay by Xunzi)
...“Rectification of Names” is liberally sprinkled with comments about the adverse social consequences attending the abuse and misuse of language. Among his other famous essays, “A Discussion of Music” became the classic work on the subject in China. Here, too, social issues are under consideration as Xunzi discusses the importance of music as a vehicle for expressing.....
Discussion of Ritual, A (essay by Xunzi)
One may ask how, if man is born “evil” (by which Xunzi really meant uncivilized), it is possible for him to create the higher values of civilization. In the essay “A Discussion of Ritual,” Xunzi attempts to answer this question and in the process elaborates the concept central to his entire philosophy. Xunzi asserts that man differs from other creatures in one vital......
Discussion with Heracleides (work by Origen)
...Origen continued his travels. In 235 the persecution of Maximinus found him in Cappadocia, from which he addressed to Ambrose his Exhortation to Martyrdom. During this period falls the “Discussion with Heracleides,” a papyrus partially transcribing a debate at a church council (probably in Arabia) where a local bishop was suspected of denying the preexistence of the......
Disdéri, André-Adolphe-Eugène (French photographer)
French photographer noted for his popularization of the carte-de-visite, a small albumen print mounted on a 212 × 4 inch (6 × 10.2 cm) card and used as a calling card....
disease
a harmful deviation from the normal structural or functional state of an organism. A diseased organism commonly exhibits signs or symptoms indicative of its abnormal state. Thus, the normal condition of an organism must be understood in order to recognize the hallmarks of disease. Nevertheless, a sharp demarcation between disease and health is not always apparent....
disease control (agriculture)
Successful disease control requires thorough knowledge of the causal agent and the disease cycle, host-pathogen interactions in relation to environmental factors, and cost. Disease control starts with the best variety, seed, or planting stock available and continues throughout the life of the plant. For harvested crops, disease control extends through transport, storage, and marketing.......
disease control (public health)
...world needs to know about outbreaks of these and other potentially virulent “emerging diseases” as soon as they appear, anywhere on the globe. Public health workers need to take steps to prevent epidemics from spreading, and the public needs to know how to protect itself....
disease devil mask (Sinhalese art)
...by Chinese children and the cholera masks worn during epidemics by the Chinese and Burmese. The disease mask is most developed among the Sinhalese in Sri Lanka, where 19 distinct rakasa, or disease devil masks, have been devised. These masks are of ferocious aspect, fanged, and with startling eyes. Gaudily coloured and sometimes having articulating jaws, they present a dragon-like......
disease elimination
...prevalence was attributed to a resolution passed in 1991 by the World Health Assembly (the governing body of the World Health Organization [WHO]) that was designed to eliminate the disease by 2000. Disease elimination was defined as a reduction of prevalence to less than 1 case per 10,000 persons. Of the 122 countries targeted for leprosy elimination, 119 had achieved this goal by the early......
disease eradication
...and rejecting diseased plants. Federal and state plant quarantines, or embargoes, have been established to prevent introduction of potentially destructive pathogens into areas currently free of the disease. More than 150 countries now have established quarantine regulations....
disease: Year In Review 1993
In 1993 exciting developments in the application of genetics to the diagnosis, understanding, and potential treatment of a number of diseases shared the stage with the worsening epidemics of AIDS and tuberculosis (TB). The year was also marked by growing concern not only about the emergence of previously unrecognized infectious diseases but ...
disease: Year In Review 1994
In 1994 scientists made major strides in understanding the genetic underpinnings of a number of conditions, including inherited forms of cancer, the skin disease psoriasis, dyslexia (a learning disorder), and even obesity. At the same time, public health...
disease: Year In Review 1995
Celebrities attracted international attention to a variety of medical causes in 1995. The announcement in late 1994 that former U.S. president Ronald Reagan was suffering from Alzheimer’s disease led to the establishment of a new institute to conduct research into this brain disorder. Baseball legen...
disease: Year In Review 1996
Health issues played a prominent role in politics around the world in 1996. In the United States, Pres. Bill Clinton made the prevention of tobacco use by children a campaign issue. His Republican opponent, Bob Dole, citing statistics showing a resurgence in teenage drug use, charged the Clinton administration with failure to combat drug abuse among American youth. While Dole opposed abortion, Cli...
disease: Year In Review 1997
The degree to which medical and scientific experts should interfere with the natural order of things, in both creating and terminating life, became a major concern in medical science in 1997. In February a startled world said hello to a cloned Scottish sheep named Dolly. The surprising scientific feat stirred moral and legal concerns about the prospect that genetically identical...
disease: Year In Review 1998
In 1998 antibiotic-resistant organisms were spreading in both less-developed and industrialized countries, a situation that was presenting an increasing threat to public health worldwide. The global scope of tuberculosis (TB) was highlighted by a World Health Organization...
disease: Year In Review 1999
In 1999 the international team of scientists participating in the $3 billion Human Genome Project made impressive strides toward the goal of locating, analyzing, and identifying virtually every one of the estimated 100,000 human genes. On December 1 it was announced that cooperating scientists from four in...
disease: Year In Review 2000
There are very few years in which a single achievement in medicine overshadows all others. Such a year was 2000, however, and such an achievement was the sequencing of the entire human genome....
disease: Year In Review 2001
The medical response to the havoc wreaked by four jetliner crashes on September 11 due to terrorist activity was massive and rapid at all three impact sites: Lower Manhattan, the Pentagon in Virginia, and rural Shanksville, Pa. It was in New York City, however, that the need for an unprecedented level of t...
disease: Year In Review 2002
Bioterrorism preparedness became a national priority in many countries in 2002 in the wake of the previous year’s September 11 terrorist attacks and subsequent anthrax mailings in the U.S. The possibility that terrorists would use deadly pathogens as weapons underscored the need for new drugs to treat and prevent infectious diseases. The Pharmaceutical Research and Manufa...
disease: Year In Review 2003
In early 2003 a virulent new infectious disease caught the world off guard. The Chinese Ministry of Health reported to the World Health Organization (WHO) in mid-February that 305 people in Guangdong province had developed an acute pneumonia-like illness and that 5 of them had died. Laboratory tests had been negative for ...
disease: Year In Review 2004
More than 17,000 delegates gathered in Bangkok on July 11–16, 2004, for the 15th International AIDS Conference, the theme of which was “Access for All.” The biennial event had evolved from a strictly scientific conference into a forum that covered all facets of the HIV/AIDS pandemic and was attended by persons who represented a large varie...
disease: Year In Review 2005
“We don’t know when it will start, we don’t know where it will start, we don’t know how severe it will be, we don’t even know for certain from where the causative virus will come.” So said David Nabarro, senior coordinator of the UN response to avian influenza, or “bird flu,” in a BBC News interview in No...
disease: Year In Review 2006
June 5, 2006, marked the 25th anniversary of the first published report of an unknown deadly infectious disease that had sickened five previously healthy young men in Los Angeles. The disease—acquired immunodeficiency syndrome (AIDS), which is caused by the human immunodeficiency virus (HIV)—soon grew into a global pandemic, and in the quarter century since that report, HIV had infec...
disease: Year In Review 2007
Along with shifting climate patterns, scientists were concerned that climate change would contribute to the spread of infectious diseases. In 2007 the Intergovernmental Panel on Climate Change released a report that predicted that global warming could create unprecedented health risks, including deadly heat waves, droughts, rising sea levels, and fierce storms. Flooding and drought could lead to c...
disease: Year In Review 2008
In 2008 the contamination of infant formula and related dairy products with melamine in China led to widespread health problems in children, including urinary problems and possible renal-tube blockages and kidney stones. According to the World Health Organization (WHO), by late 2008 the contamination had led to four infant...
disease: Year In Review 2009
In 2009 American scientists made significant progress in their understanding of how HIV infects humans. In August researchers at the University of North Carolina at Chapel Hill reported having decoded the structure of a complete HIV genome. Their analysis of the architecture of the virus’s genome found that its RNA structure plays a key role in its infe...
disease: Year In Review 2010
While researchers in 2010 reported progress in the treatment and prevention of AIDS—from a promising new vaccine to a preventative vaginal gel—drug-resistant strains of HIV threatened to create a new set of challenges for the world health community. A study published online in January in the journal Science raised concerns that a flood of new infections could occur in the next...
Diseases (works attributed to Hippocrates)
...are frequent subjects. Other treatises explain how to set fractures and treat wounds, feed and comfort patients, and take care of the body to avoid illness. Treatises called Diseases deal with serious illnesses, proceeding from the head to the feet, giving symptoms, prognoses, and treatments. There are works on diseases of women, childbirth, and pediatrics.......
Diseases of Memory (work by Ribot)
French psychologist whose endeavour to account for memory loss as a symptom of progressive brain disease, iterated in his Les Maladies de la mémoire (1881; Diseases of Memory), constitutes the most influential early attempt to analyze abnormalities of memory in terms of physiology....
Diseases of the Heart (work by Mackenzie)
...the beat of the heart itself. This instrument enabled Mackenzie to make important and original distinctions between harmless and dangerous types of pulse irregularities. In his ambitious text Diseases of the Heart (1908), Mackenzie summarized his diagnostic work on pulsation and cardiovascular disease. He also convincingly demonstrated the efficacy of the drug digitalis in the......
Diseases of the Heart and Aorta, The (work by Stokes)
Stokes’s two most important works were A Treatise on the Diagnosis and Treatment of Diseases of the Chest, published in 1837, and The Diseases of the Heart and Aorta, published in 1854. He was also the author of one of the first works in English on the use of the stethoscope. Stokes also gave his name to a type of breathing characteristic of advanced myocardial degeneration,.....
Diseases of Workers (work by Ramazzini)
Ramazzini wrote De Morbis Artificum Diatriba (1760; Diseases of Workers), the first comprehensive work on occupational diseases, outlining the health hazards of irritating chemicals, dust, metals, and other abrasive agents encountered by workers in 52 occupations. He served as professor of medicine at the University of Padua from 1700 until his death....
diseconomy of scale (economics)
...labour supply, better specialization, improved technology, and discovery of new resources or better implementation of existing ones all can increase output and lead to economy of scale. Conversely, diseconomy of scale can result when an increase in output causes the average cost to increase....
Disegno, Accademia del (art institution, Florence, Italy)
...c. 1490), which seems to have been simply a social gathering of amateurs meeting to discuss the theory and practice of art. The first true academy for instruction, the Accademia del Disegno (“Academy of Design”), was established in 1563 in Florence by the grand duke Cosimo I de’ Medici at the instigation of the painter and art historian Giorgio Vasari. The two nomina...
Disenchanted, The (novel by Schulberg)
...crimes for the Nürnberg trials. In 1947 he published his second novel, The Harder They Fall, a fictional exposé of corrupt practices in professional boxing. In 1950 his novel The Disenchanted won an American Library Award for fiction. In 1954 his screenplay for the widely acclaimed On the Waterfront won him an Academy Award for best story and screenplay. In th...
Disenchantment (work by Montague)
...Among his other works are the pre-war novel A Hind Let Loose (1910), a lighthearted satirical fantasy of journalistic life, and two works based on his experiences in World War I—Disenchantment (1922), an essay drawn from wartime diaries and articles that expresses the bitterness of the survivors, and Fiery Particles (1923), comic and tragic stories of life in the......
disequilibrium (economics)
Whatever its merits from a long-term point of view, the idea that it is quite respectable for a country to alter the par value of its currency in certain circumstances had disturbing effects on the movements of short-term funds—effects that may not have been clearly foreseen at the time of Bretton Woods. Such movements of funds were sometimes very large indeed. These movements were not......
disequilibrium dating (geology)
...have relatively short half-lives, none remains since the creation of the elements, but instead they are continuously provided by the decay of the long-lived parent. This type of dating, known as disequilibrium dating, will be explored below in the section Uranium-series disequilibrium dating....
Disgaea (electronic game)
electronic game released by the Japanese video-game company Nippon Ichi Software for the Sony Corporation’s PlayStation 2 console in 2003 under the title Netherworld Battle Chronicle: Disgaea. The game was released in the United States the same year under...
“Disgaea: The Hour of Darkness” (electronic game)
electronic game released by the Japanese video-game company Nippon Ichi Software for the Sony Corporation’s PlayStation 2 console in 2003 under the title Netherworld Battle Chronicle: Disgaea. The game was released in the United States the same year under...
disgorging (wine making)
...This procedure, called riddling, or remuage, has been largely mechanized since the 1970s. When the wine is mature and ready for the market, the deposits are removed in a process called dégorgement. In this process, the cork is carefully pried off, allowing the internal pressure in the bottle to shoot the sediment out; this is sometimes done after the neck of the bottle......
Disgrace (novel by Coetzee)
...19th-century Russia (particularly to Fyodor Dostoyevsky’s work The Devils); both books treat the subject of literature in society. In 1999, with his novel Disgrace, Coetzee became the first writer to win the Booker Prize twice. After the novel’s publication and an outcry in South Africa, he moved to Australia, where he was granted ...
disguised unemployment (economics)
Two theories emphasized the existence of surplus resources in developing countries as the central challenge for economic policy. The first concentrated on the countries with relatively abundant natural resources and low population densities and argued that a considerable amount of both surplus land and surplus labour might still exist in these countries because of inadequate marketing......
disguising (architecture)
...of those such as the Gothic and modern, in which new techniques excite a search for the interpretive design of their materials and methods. More often than not, both materials and methods have been disguised by decorative forms or surfacing such as veneers, stucco, or paint, because of emphasis on the expression of content or of form. Most early stone architecture in Egypt, Greece, and India......
disguising (drama)
traditional dramatic entertainment, still performed in a few villages in England and Northern Ireland, in which a champion is killed in a fight and is then brought to life by a doctor. It is thought likely that the play has links with primitive ceremonies held to mark important stages in the agricultural year. The name has b...
dish (electronics)
A widely used form of radar antenna is the parabolic reflector, the principle of which is shown in cross section in part A of the figure. A horn antenna or other small antenna is placed at the focus of the parabola to illuminate the parabolic surface of the reflector. After being reflected by this surface, the electromagnetic energy is radiated as a narrow beam. A......
dish antenna (electronics)
A widely used form of radar antenna is the parabolic reflector, the principle of which is shown in cross section in part A of the figure. A horn antenna or other small antenna is placed at the focus of the parabola to illuminate the parabolic surface of the reflector. After being reflected by this surface, the electromagnetic energy is radiated as a narrow beam. A......
dishdasha (garment)
...of heavy cream-coloured wool decorated with brightly coloured stripes or embroidery. A voluminous outer gown still worn throughout the Middle East in the Arab world is the jellaba, known as the jellabah in Tunisia, a jubbeh in Syria, a ......
dishdashah (garment)
...of heavy cream-coloured wool decorated with brightly coloured stripes or embroidery. A voluminous outer gown still worn throughout the Middle East in the Arab world is the jellaba, known as the jellabah in Tunisia, a jubbeh in Syria, a ......
Dishonored (film by Sternberg [1931])
...help, Dietrich began to develop her legend by cultivating a femme fatale film persona in several von Sternberg vehicles that followed—Morocco (1930), Dishonored (1931), Shanghai Express (1932), Blonde Venus (1932), The Scarlet Empress (1934), and ......
disilicate (mineral)
compound with a structure in which silicate tetrahedrons (a central silicon atom surrounded by four oxygen atoms at the corners of a tetrahedron) are arranged in sheets. Examples are talc and mica. Three of the oxygen atoms of each tetrahedron are shared with other tetrahedrons, but no two tetrahedrons have more than one oxygen atom in common; each tetrahedron, therefore, is lin...
disinfectant
any substance, such as creosote or alcohol, applied to inanimate objects to kill microorganisms. Disinfectants and antiseptics are alike in that both are germicidal, but antiseptics are applied primarily to living tissue. The ideal disinfectant would rapidly destroy bacteria, fungi, viruses, and protozoans, would not corrode surgical instrum...
disinfection (public health)
...antiseptics are general protoplasmic poisons and if used in sufficient concentration are harmful to the body’s cells and tissues as well as to bacteria. Thus an antiseptic is most valuable in the disinfection of contaminated wounds or skin surfaces when there is a wide margin between its bactericidal and toxic concentrations. When, however, an antiseptic is to be used to disinfect......
disinflation (economics)
Although deflation persisted, it was on a downward trend. The core inflation rate (excluding fresh food but not energy products) fell 0.1% in the third quarter. Land prices nationwide were falling more slowly, and in Tokyo they rose for the first time in 15 years....
disinformation
dissemination of information—facts, arguments, rumours, half-truths, or lies—to influence public opinion....
disinheritance (law)
In the modern civil law, two systems are used to provide protection against disinheritance. Under the French system, a testator who is survived by descendants, parents, or (in some countries) brothers, sisters, or even other close relatives, cannot dispose at all of the “reserved portion” of his estate, the size of which depends upon the number and the degree of nearness of......
Disinherited, The (work by Castillo)
...he was sent to Nazi concentration camps with his mother, who was a political radical. Tanguy and Le Colleur d’affiches (1958; The Disinherited) deal with these two traumatic experiences. They show the disarray of a young mind prematurely falling prey to political skepticism and religious doubt, without losing fait...
disintegration
property exhibited by certain types of matter of emitting energy and subatomic particles spontaneously. It is, in essence, an attribute of individual atomic nuclei....
disintegration constant (nuclear physics)
proportionality between the size of a population of radioactive atoms and the rate at which the population decreases because of radioactive decay. Suppose N is the size of a population of radioactive atoms at a given time t, and dN is the amount by which the population decreases in time d...
disintegration energy (nuclear physics)
In many types of detectors, a single particle or quantum of radiation liberates a certain amount of charge Q as a result of depositing its energy in the detector material. For example, in a gas, Q represents the total positive charge carried by the many positive ions that are produced along the track of the particle. (An equal charge of opposite sign is carried by the free......
disintegration, nuclear
property exhibited by certain types of matter of emitting energy and subatomic particles spontaneously. It is, in essence, an attribute of individual atomic nuclei....
dísir (mythology)
in Germanic mythology, any of a group of supernatural beings who corresponded to the Greek Moirai; they were usually represented as three maidens who spun or wove the fate of men. Some sources name them Urd, Verdandi, and Skuld, perhaps meaning “past,” “present,” and “future.” They w...
disjoint sets (mathematics)
...set of all positive odd numbers, then their union yields the entire set of positive integers, and their intersection is the empty set. Any two sets whose intersection is the empty set are said to be disjoint....
disjunction (logic)
in logic, relation or connection of terms in a proposition to express the concept “or”; it is a statement of alternatives (sometimes called “alternation”). For clarity, exclusive disjunction (either x or y, but not both), symbolized x ⊻ y, must be distinguished from inclusive disjunction (either ...
disk (anatomy)
...of fibrocartilage that are attached to the joint capsule (the investing ligament) and that stretch across the joint cavity between a pair of conarticular surfaces. When complete they are called disks; when incomplete they are called menisci. Disks are found in the temporomandibular joint of the lower jaw, the sternoclavicular (breastbone and collarbone) joint, and the ulnocarpal (inner......
DISK (Turkish labour organization)
Industrial development, urbanization, and the growth of trade unions provided a base for the development of a radical left that included a new trade union federation, the Confederation of Reformist Workers’ Unions (Devrimci Işçi Sendıkalari Konfederasyonu [DİSK]; founded 1967); a revolutionary youth movement, Dev Genç (1969); a socialist political party, t...
disk (farm machine)
Modern harrows comprise several varieties. Disk harrows mount concave disks and are frequently referred to simply as disks. One type, the single-action two gang, has two groups of disks, more or less horizontally aligned, with opposing concavities, that throw the soil in opposite directions. The tandem harrow has two to four gangs in tandem, and the offset has two to three gangs in tandem on......
disk (galactic)
From a distance the most conspicuous part of the Galaxy would be the disk, which extends from the nucleus out to approximately 75,000 light-years. The Galaxy resembles other spiral systems, featuring as it does a bright, flat arrangement of stars and gas clouds that is spread out over its entirety and marked by a spiral structure. The disk can be thought of as being the underlying body of stars......
disk bat (bat)
any of three species of bats inhabiting Central America and northern South America that are distinguished by round disks at the base of the thumb and on the sole of the foot....
disk brake (engineering)
Disc brakes, originally developed for aircraft, are ubiquitous, in spite of their higher cost, because of their fade resistance. Although there are some four-wheel systems, usually discs are mounted on the front wheels, and conventional drum units are retained at the rear. They have been standard on most European automobiles since the 1950s and most American models since the mid-1970s. Each......
disk cache memory (computing)
...if the information it needs is stored in the cache. If it is, the cache returns the data to the processor. If the information is not in the cache, the processor retrieves it from the main memory. Disk cache memory operates similarly, but the cache is used to hold data that has been recently written on, or retrieved from, a magnetic disk or other external storage device....
disk cam (machine part)
Cams are made in a variety of forms, such as: (1) a rotating disk or plate with the required profile; (2) a plate with a groove cut on its face to fit a roller on the follower (face cam); (3) a cylindrical or conical member with a follower groove cut around the surface; (4) a cylinder with the required profile cut in the end (end cam); (5) a reciprocating wedge of the required shape....
disk capacitor (electronics)
...mixing, precise control of the barium-titanium ratio, high purity, and submicrometre particle size. Processing of the resulting powder varies according to whether the capacitor is to be of the disk or multilayer type. Disks are dry-pressed or punched from tape and then fired at temperatures between 1,250° and 1,350° C (2,280° and 2,460° F). Silver-paste screen-printe...
disk centrifuge (chemistry)
The disk-type centrifuge consists of a vertical stack of thin disks in the shape of cones. The sedimentation takes place in the radial direction in the space between adjacent cones. This greatly reduces the settling distance and hence increases the rate at which the material is separated. The angle of the cones is designed so that upon reaching the inside surface of the cone the heavier......
disk component (galactic)
From a distance the most conspicuous part of the Galaxy would be the disk, which extends from the nucleus out to approximately 75,000 light-years. The Galaxy resembles other spiral systems, featuring as it does a bright, flat arrangement of stars and gas clouds that is spread out over its entirety and marked by a spiral structure. The disk can be thought of as being the underlying body of stars......
disk cutter (machine)
American moles have developed two types of cutters: disk cutters that wedge out the rock between initial grooves cut by the hard-faced rolling disks, and roller-bit cutters using bits initially developed for fast drilling of oil wells. As later entrants in the field, European manufacturers have generally tried a different approach—milling-type cutters that mill or plane away part of the......
disk fibula (ornament)
...to be set. The most widely used type of fibula was the so-called buckler variety, with a fan head, arched bridge, and flat or molded foot, with pierced work in various shapes. Equally common were disk fibulae, either flat or with concentric embossing, while S-shaped fibulae and belt buckles were rarer....
disk film (photography)
Some compact mass-market cameras take circular disks of film, 65 millimetres in diameter, in light-tight cartridges and coated on a 0.18-mm polyester base. In the camera the disk rotates as up to 15 exposures (frame size 8 × 10 millimetres) are recorded around the disk circumference. The disk lies flatter in the camera than rolled-up film and is suitable for more automated photofinishing;.....
disk flower (plant anatomy)
...simplest type is the discoid head, in which the flowers have a regular, tubular corolla, with generally four or five apical teeth representing the tips of the petals. This kind of flower is called a disk flower. Ordinarily, the flowers in a discoid head are all perfect (bisexual) and fertile. Thistles and ageratums are examples of Asteraceae species with discoid heads....
disk harrow (farm machine)
Modern harrows comprise several varieties. Disk harrows mount concave disks and are frequently referred to simply as disks. One type, the single-action two gang, has two groups of disks, more or less horizontally aligned, with opposing concavities, that throw the soil in opposite directions. The tandem harrow has two to four gangs in tandem, and the offset has two to three gangs in tandem on......
disk, intervertebral (anatomy)
...or thirties, when deposits of ochre pigments begin to appear in various fibrous connective tissues of the body. The pigment, bound to collagen fibres in the deeper layers of joint cartilage and intervertebral disks (the fibrous pads between adjacent bones of the spine), causes these tissues to lose their normal resiliency and become brittle. The erosion of the abnormal cartilage leads to a......
disk jockey (radio personality)
person who conducts a program of recorded music on radio, on television, or at discotheques or other dance halls. Disc jockey programs became the economic base of many radio stations in the United States after World Wa...
disk, magnetic (electronics)
Magnetic disks are coated with a magnetic material such as iron oxide. There are two types: hard disks made of rigid aluminum or glass, and removable diskettes made of flexible plastic. In 1956 the first magnetic hard drive (HD) was invented at IBM; consisting of 50 21-inch (53-cm) disks, it had a storage capacity of 5 megabytes. By the 1990s the standard HD diameter for PCs had shrunk to 3.5......
disk operating system (operating system)
the dominant operating system for the personal computer (PC) throughout the 1980s. The acquisition and marketing of MS-DOS were pivotal in the Microsoft Corporation’s transition to software industry giant....
disk pack (computer technology)
...used to read the magnetic impressions on the disk, can be positioned anywhere on the disk with great precision. For computer data-storage applications, a collection of as many as 20 disks (called a disk pack) is mounted vertically on the spindle of a drive unit. The drive unit is equipped with multiple reading/writing heads....
disk plow (farm machine)
Disk plows usually have three or more individually mounted concave disks that are inclined backward to achieve maximum depth. They are particularly adapted for use in hard, dry soils, shrubby or bushy land, or on rocky land. Disk tillers, also called harrow plows or one-way disk plows, usually consist of a gang of many disks mounted on one axle (see harrow). Used....
disk population (astronomy)
...the older objects are. Their motions in the Galaxy follow elliptical paths, whereas circular orbits are characteristic of younger stars. They belong to the type of distribution often called a “disk population,” to distinguish them from the Population II (very old) and Population I (young) objects proposed by the German American astronomer Walter Baade. There is a wide variation in...
disk refiner (instrument)
Like other refiners, the disk refiner consists of a rotating bladed element that moves in conjunction with a stationary bladed element. The disk refiner’s plane of action, however, is perpendicular to the axis of rotation, simplifying manufacture of the treating elements and replacement. Since the disk refiner provides a large number of working edges to act upon the fibre, the load per fibr...
disk sander (tool)
...smoothing, polishing, or cleaning a surface, as of wood, plastic, or metal. Sanders are also used to roughen surfaces in preparation for finishing. There are three main types of power sanders: the disk sander, the belt sander, and the orbital sander. In the disk sander an abrasive disk is attached to a shaft that is driven by bevel gears to rotate about an axis at right angles to the motor......
disk tiller (agriculture)
...or more individually mounted concave disks that are inclined backward to achieve maximum depth. They are particularly adapted for use in hard, dry soils, shrubby or bushy land, or on rocky land. Disk tillers, also called harrow plows or one-way disk plows, usually consist of a gang of many disks mounted on one axle (see harrow). Used after grain harvest, they.....
disk-and-wheel integrator (instrument)
The earliest integrator was a mechanical instrument called the planimeter (q.v.). The illustration (top) shows a simple mechanical integrator of the disk-and-wheel variety, which has essential parts mounted on mutually perpendicular shafts, with a means of positioning the wheel in frictional contact with the disk, or turntable. In use, an angular displacement of the disk causes the wheel......
disk-type centrifuge (chemistry)
The disk-type centrifuge consists of a vertical stack of thin disks in the shape of cones. The sedimentation takes place in the radial direction in the space between adjacent cones. This greatly reduces the settling distance and hence increases the rate at which the material is separated. The angle of the cones is designed so that upon reaching the inside surface of the cone the heavier......
disk-winged bat (bat)
any of three species of bats inhabiting Central America and northern South America that are distinguished by round disks at the base of the thumb and on the sole of the foot....
diskette (computing)
Magnetic storage medium used with computers. Floppy disks are made of flexible plastic coated with a magnetic material, and are enclosed in a hard plastic case. They are typically 3.5 in. (9 cm) in diameter. Data are arranged on their surfaces in concentric tracks. A disk is inserted in the computer’s floppy disk drive, an assembly of ...
Disklavier (musical instrument)
By the 1990s the Yamaha Corporation, a Japanese piano manufacturer, had introduced the “Disklavier,” an acoustic player piano equipped with a computer that, by reading data on a floppy disc or compact disc, could re-create on the piano virtually every nuance of a performance—the tone, touch, timing, and dynamic range of a real performance. The key-striking and pedaling......