| | - autofocus
- (from the article "photography, technology of") Some cameras evaluate the coincidence (or lack thereof) between two rangefinder images by image analysis with a microchip system. This signals electronically when the lens is set to the correct distance and often carries out the distance setting by a servomotor built into the camera. Such focusing automation makes the ...
- autogamy
- (from the article "self-fertilization") ...of male and female gametes (sex cells) produced by the same individual. Self-fertilization occurs in bisexual organisms, including most flowering plants, numerous protozoans, and many invertebrates. Autogamy, the production of gametes by the division of a single parent cell, is frequently found in unicellular organisms such as the protozoan Paramecium. ...
- autogenous fly
- (from the article "dipteran") ...an insufficient larval diet. Although one batch of eggs occasionally is laid without a meal of blood, blood is necessary to mature a second batch. Flies that lay one batch of eggs without blood are autogenous; those that cannot lay at all without blood are anautogenous. One species can have ...
- autogenous mill
- (from the article "mineral processing") A special development is the autogenous or semiautogenous mill. Autogenous mills operate without grinding bodies; instead, the coarser part of the ore simply grinds itself and the smaller fractions. To semiautogenous mills (which have become widespread), 5 to 10 percent grinding bodies (usually metal spheres) are added.
- autogiro
- rotary-wing aircraft, superseded after World War II by the more efficient helicopter. It employed a propeller for forward motion and a freely rotating, unmotorized rotor for lift. In searching for an aircraft that could be slowed down in flight and landed vertically, experimenters built many prototypes that were difficult to ... [4 Related Articles]
- autograph
- any manuscript handwritten by its author, either in alphabetical or musical notation. (The term also refers to a person's handwritten signature.) Aside from its antiquarian or associative value, an autograph may be an early or corrected draft of a manuscript and provide valuable evidence of the stages of composition or ... [1 Related Articles]
- autoharp
- stringed instrument of the zither family popular for accompaniment in folk music and country and western music. A musician may position the instrument on a table, on the lap while seated, or resting against the left shoulder. An autoharp player strums the strings with a stiff felt or plastic pick ... [1 Related Articles]
- autohypnosis
- hypnosis that is self-induced. Though feasible and possibly productive of useful results, it is often a sterile procedure because the autohypnotist usually tries too hard to direct consciously the activities that he wishes to take place at the hypnotic level of awareness, thus nullifying the effort. A form of self-hypnosis, ... [1 Related Articles]
- autoimmune antibody
- (from the article "muscle disease") Autoimmune antibodies (those produced against the body's own cells) cause the destruction of acetylcholine receptors of the neuromuscular junction. Removal of the thymus, treatment with high doses of corticosteroids (which depress the immune response) and anticholinesterase medications (which stimulate the transmission of nerve impulses), and plasmapheresis (a procedure in which ...
- autoimmune disease
- (from the article "Disorders of the immune system") The mechanism by which the enormous diversity of B and T cells is generated is a random process that inevitably gives rise to some receptors that recognize the body's own constituents as foreign. Lymphocytes bearing such self-reactive receptors, however, are eliminated or rendered impotent by several different mechanisms, so that ...
- autoimmune gastritis
- (from the article "pernicious anemia") ...rapid heartbeat, unsteady gait, smooth tongue, gastrointestinal disturbances, and neurological problems. Pernicious anemia is in most cases associated with an inflammation of the stomach called autoimmune gastritis. An absence of hydrochloric acid in gastric secretions (achlorhydria) is also characteristic of pernicious anemia. The anemia may become severe before the disorder ...
- autoimmune hemolytic anemia
- (from the article "autoantibody") Autoantibodies damage body tissues by bringing about the phagocytosis (ingestion) or lysis (bursting) of healthy cells. Blood cells are common targets of these actions. In autoimmune hemolytic anemia, for example, certain autoantibodies bind to red blood cells. This chemical binding activates the complement system, a series of proteins in the ...
- autoimmune hepatitis
- (from the article "hepatitis") ...with some illnesses, such as Wilson disease and alpha-1-antitrypsin deficiency. Chronic hepatitis B primarily affects males, whereas chronic hepatitis C arises in equal numbers in both sexes. Autoimmune hepatitis, a disorder associated with a malfunction of the immune system, generally occurs in young women. Treatment for autoimmune hepatitis includes corticosteroids, ...
- autoimmunity
- the state in which the immune system reacts against the body's own normal components, producing disease or functional changes. [4 Related Articles]
- autokinetic effect
- illusory movement of a single still object, usually a stationary pinpoint of light used in psychology experiments in dark rooms. As one stares at a fixed point of light, one's eye muscles become fatigued, causing a slight eye movement. Without the usual reference points available in the everyday environment, the ... [2 Related Articles]
- autolith
- (from the article "xenolith") ...magma while it was still fluid, may be located near their original positions of detachment or may have settled deep into the intrusion, if their density is greater. Xenoliths can be contrasted with autoliths, or cognate xenoliths, which are pieces of older rock within the intrusion that are genetically related ...
- autologous bone-marrow rescue
- (from the article "cryopreservation") An important application of cryopreservation is in the freezing and storage of hematopoietic stem cells, which are found in the bone marrow and peripheral blood. In autologous bone-marrow rescue, hematopoietic stem cells are collected from a patient's bone marrow prior to treatment with high-dose chemotherapy. Following treatment, the patient's cryopreserved ...
- autologous transfusion
- (from the article "therapeutics") Autologous transfusion is the reinfusion of one's own blood. The blood is obtained before surgery and its use avoids transfusion reactions and transfusion-transmitted diseases. Donation can begin one month before surgery and be repeated weekly, depending on the number of units likely to be needed. Intraoperative blood salvage is another ...
- autologous transplant
- (from the article "cancer") ...(The phrase stem cell therapy is more accurate than bone marrow transplantation, since it has become common whenever possible to collect stem cells from the blood.) An autologous transplant involves the harvesting and storage of the patient's own stem cells before therapy. After the patient has received ...
- Autolycus
- in Greek mythology, the maternal grandfather, through his daughter Anticleia, of the hero Odysseus. In Homer's Odyssey the god Hermes rewards Autolycus's faithful sacrifices to him by granting Autolycus skill in trickery, but later ancient authors made him the god's son. He was believed to live at ...
- autolysis
- (from the article "poison") ...may appear in the culture medium in which the bacteria are growing during the declining phases of growth; in some cases they are released at the time of normal destruction of the cells after death (autolysis). The exotoxins are less stable to heat than are the endotoxins, and they may ...
- Automat
- any of a chain of cafeterias in New York City and Philadelphia, where low-priced prepared food and beverages were obtained, especially from coin-operated compartments.
- automata theory
- body of physical and logical principles underlying the operation of any electromechanical device (an automaton) that converts information from one form into another according to a definite procedure. Real or hypothetical automata of varying complexity have become indispensable tools for the investigation and implementation of systems that have structures amenable ... [1 Related Articles]
- automated assembly machine
- (from the article "automation") Automated assembly machines have been developed that operate in a manner similar to machining transfer lines, with the difference being that assembly operations, instead of machining, are performed at the workstations. A typical assembly machine consists of several stations, each equipped with a supply of components and a mechanism for ...
- automated clearinghouse
- (from the article "money") The automated clearinghouse (ACH) is the third alternative means of making deposits and paying bills. ACH networks transfer existing deposit balances, avoid the use of checks, and speed payments and settlement. In addition, many large payments (such as those to settle securities or foreign exchange transactions between financial institutions) are ...
- Automated Content Access Protocol
- (from the article "Media and Publishing") ...channel. Initiatives were under way in several countries that would allow publishers to make their works available through a broad range of intermediaries. The most notable initiative was the Automated Content Access Protocol (<www.the-acap.org>), an industry standard for coordinating the access and use of online content, including published articles, books, ...
- automated guideway transit
- (from the article "mass transit") When the PRT concept is extended to larger (15-25-passenger) vehicles, the term automated guideway transit (AGT) is sometimes applied. AGT systems have been built to provide circulation in downtown areas (e.g., Detroit, Mich., and Miami, Fla., both in the United States) and on a dispersed American college campus (West Virginia ...
- automated teller machine
- (from the article "money") Four very different types of transfer can be distinguished. First, depositors can use electronic funds transfers (EFTs) to withdraw currency from their accounts using automated teller machines (ATMs). In this way an ATM withdrawal works like a debit card. ATMs also allow users to deposit checks into their accounts or ...
- automatic attention
- (from the article "attention") ...short-term storage. (Indeed, some focal attention is almost certainly necessary for storing information in the memory at all.) Focal attention is flexible but makes great demands on brain capacity. Automatic attention makes fewer demands but is relatively inflexible, as it cannot cope with the unexpected. The focal and automatic modes ...
- Automatic Bargain Basement
- (from the article "Filene's") Well-known for its high-quality fashion merchandise, Filene's became famous for its Automatic Bargain Basement. This unique basement store was opened in 1909, selling "distress merchandise" (damaged, outdated, or unpopular items) at bargain prices, as did many other stores' basements, but at Filene's the prices were plainly marked and were automatically ...
- automatic body tilting
- (from the article "railroad") The permissible maximum speed of a passenger train through curves is the level beyond which a railroad considers passengers will suffer unacceptable centrifugal force; the limit beyond which derailment becomes a risk is considerably higher. On a line built for exclusive use of high-speed trains, curved track can be canted, ...
- Automatic Computing Engine
- (from the article "Turing, Alan M.") In 1945, the war being over, Turing was recruited to the National Physical Laboratory (NPL) in London to design and develop an electronic computer. His design for the Automatic Computing Engine (ACE) was the first relatively complete specification of an electronic stored-program general-purpose digital computer. Had Turing's ACE been built ...
- automatic detection
- (from the article "attention") ...under the individual's control in that it can be readily altered or even reversed. It is strongly dependent on the stimulus load. It has been suggested that it uses short-term memory. By contrast, automatic detection, or automatic processing, operates in long-term memory and is dependent upon extensive learning. It comes ...
- automatic detection and tracking radar
- (from the article "radar") ...to enter a radar receiver and produce spurious responses. Well-trained operators are not often deceived by interference, though they may find it a nuisance. Interference is not as easily ignored by automatic detection and tracking systems, however, and so some method is usually needed to recognize and remove interference pulses ...
- automatic dialogue replacement
- (from the article "motion-picture technology") ...while watching the scene over and over. The actor rehearses the line so that it matches the wording and lip movements and then a recording is made. The cutting of loops has largely been replaced by automatic dialogue replacement (ADR). Picture and sound are interlocked on machines that can run ...
- automatic feedback control system
- (from the article "automation") Advances in sensor technology have provided a vast array of measuring devices that can be used as components in automatic feedback control systems. These devices include highly sensitive electromechanical probes, scanning laser beams, electrical field techniques, and machine vision. Some of these sensor systems require computer technology for their implementation. ...
- automatic film processor
- (from the article "photoengraving") ...other than immersion in solutions contained in a shallow pan or tray or by dipping into a tank of solution. Such tank and tray processing remains important but is now being supplanted by the use of automatic film-processing machines. Derived from equipment originally designed for processing of motion-picture film or ...
- automatic fine tuning control
- (from the article "television") ...prevented from changing when cameras are switched from scene to scene or when the receiver is tuned from one broadcast to another. Another enhancement is a single touch-button control that sets the fine tuning and also adjusts the hue, saturation, contrast, and brightness to preset ranges. These automatic adjustments override ...
- automatic gain control
- (from the article "television") ...times per stage, representing an overall maximum amplification on the order of 10,000 times. The amplification of these intermediate-frequency stages is automatically adjusted, by a process known as automatic gain control, in accordance with the strength of the signal, full amplification being accorded to a weak signal and less to ...
- automatic instrument
- (from the article "musical instrument") Water power, clockwork, steam, and electricity have all been used at various times to power musical instruments, enabling them to produce sound automatically. Examples include church bells, automatic organs, musical clocks, automatic pianos and harpsichords, music boxes, calliopes, and even automatic orchestras. Most of the impetus behind this phenomenon ceased ...
- automatic loom
- (from the article "textile") Automatically replenished flat, or automatic, looms are the most important class of modern loom, available for a very wide range of fabrics. In virtually all such looms, the shuttle is replenished by automatically replacing the exhausted bobbin with a full one. In principle they are thus the same as the ...
- automatic pilot
- device for controlling an aircraft or other vehicle without constant human intervention. [4 Related Articles]
- automatic pistol
- handgun that utilizes either recoil or blowback to discharge the empty cartridge after each shot, reload, and cock the piece. The automatic pistol dates from the very late 19th century, when developments in ammunition made possible cartridges and bullets that would not be deformed by their handling in automatic loading, ... [2 Related Articles]
- automatic plotting
- (from the article "map") Some success was also achieved in the difficult area of automatic plotting. Instruments now available can automatically scan a stereo model and generate approximate profiles from which contours may be interpolated. Some steps, however, must be closely monitored or else performed completely by the operator. Contouring interpolated from a profile ...
- automatic repeat request
- (from the article "telecommunication") ...if errors occur during transmission the redundant bits can be used by the decoder to determine where the errors have occurred and how to correct them. The second method of error control is called automatic repeat request (ARQ). In this method redundant bits are added to the transmitted information and ...
- automatic rifle
- rifle that utilizes either its recoil or a portion of the gas propelling the projectile to remove the spent cartridge case, load a new cartridge, and cock the weapon to fire again. Automatic rifles (and pistols) are called autoloaders and are actually semiautomatic, since they customarily fire only one shot ... [1 Related Articles]
- automatic switching
- (from the article "telephone and telephone system") The idea of automatic switching appeared as early as 1879, and the first fully automatic switch to achieve commercial success was invented in 1889 by Almon B. Strowger. The Strowger switch consisted of essentially two parts: an array of 100 terminals, called the bank, that were arranged 10 rows high ...
- automatic terrain recognition and guidance
- (from the article "rocket and missile system") ...radio-controlled guidance, which was limited essentially to the line of sight between the ground controller and the missile, covered less than the missile's potential range. However, in 1954 an automatic terrain recognition and guidance (Atran) system was added (and the missile system was subsequently designated Mace). Atran, which used radar ...
- automatic train protection
- (from the article "railroad") ...to sound in the cab of any train passing over it. If the operator fails to respond appropriately, after a short interval the train brakes are applied automatically. A refinement, generally known as automatic train protection (ATP), has been developed since World War II to provide continuous control of train ...
- automatic transmission
- arrangement of gears, brakes, clutches, a fluid drive, and governing devices that automatically changes the speed ratio between the engine and the wheels of an automobile. Since its introduction in 1939, the fully automatic transmission has become optional or standard equipment on most passenger cars. When the transmission is in ... [2 Related Articles]
- automatic writing
- in spiritualism, writing produced involuntarily when the subject's attention is ostensibly directed elsewhere. The phenomenon may occur when the subject is in an alert waking state or in a hypnotic trance, usually during a seance. What is produced may be unrelated words, fragments of poetry, epithets, puns, obscenities, or well-organized ...
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