control

1. (v.) To regulate, restrain, correct, restore to normal. 2. (n.) Ongoing operations or programs aimed at reducing a disease. 3. (n.) Members of a comparison group who differ in disease experience or allocation to a regimen from the subjects of a study. 4. (v). In statistics, to adjust or take into account extraneous influences. [Mediev. L. contrarotulum, a counterroll for checking accounts, fr. L. rotula, dim. of rota, a wheel]

- autogenous c. regulation by the action of a gene product on the gene that codes for that product.

- automatic gain c. (AGC) a feature of some hearing aid s that reduces amplification at high-input intensity levels.

- aversive c. c. of the behavior of another individual by use of psychologically noxious means; e.g., attempting to force better study habits by withholding a child's allowance, or withholding sexual contact unless the partner complies with a request.

- biologic c. c. of living organisms, including vectors and reservoirs of disease, by using their natural enemies (predators, parasites, competitors).

- birth c. 1. restriction of the number of offspring by means of contraceptive measures; 2. projects, programs, or methods to c. reproduction, by either improving or diminishing fertility.

- idiodynamic c. nervous impulses from the medulla that preserve the normal trophic condition of the muscles.

- negative c. regulation of an enzyme activity by an inhibitor of that enzyme or regulation of a protein by repression of transcription.

- own controls a method of experimental c. in which the same subjects are used in both experimental and c. conditions.

- positive c. regulation of an enzyme activity by an activator of that enzyme. Also, regulation via induction of a specific protein's biosynthesis or activation of a protein's processing.

- quality c. the c. of laboratory analytical error by monitoring analytical performance with c. sera and maintaining error within established limits around the mean c. values, most commonly ±2 SD.

- reflex c. nerve impulses transmitted to the muscles to maintain normal reflex action.

- social c. the influence on the behavior of a person exerted by other persons or by society as a whole; e.g., through appropriate social norms, ostracism, or the criminal law.

- stimulus c. the use of conditioning techniques to bring the target behavior of an individual under environmental c.. See classical conditioning.

- synergic c. impulses transmitted from the cerebellum regulating the muscular activity of the synergic units of the body.

- time-varied gain c. (TGC) SYN: time-gain compensation.

- tonic c. nerve impulses that maintain a normal tonus or level of activity in muscle or other effector organs.

- vestibulo- equilibratory c. nerve impulses transmitted from the semicircular canals, saccule, and utricle that serve to maintain the equilibrium of the body.

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con·trol kən-'trōl vb, con·trolled; con·trol·ling vt

1) to incorporate suitable controls in <a controlled experiment>

2) to reduce the incidence or severity of esp. to innocuous levels <\control an insect population> <a vaccine for controlling outbreaks of cholera> vi to incorporate controls in an experiment or study used with for <failure to \control for the difference in the rate of smoking between the two groups (Howard Bauchner )(et al)>

control n

1) an act or instance of controlling something <\control of acute intermittent porphyria>

2) one that is used in controlling something: as

a) an experiment in which the subjects are treated as in a parallel experiment except for omission of the procedure or agent under test and which is used as a standard of comparison in judging experimental effects called also control experiment

b) one (as an organism, culture, or group) that is part of a control

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con·trol (kən-trōlґ) [Fr. contrÑ„le a register] 1. the governing or limitation of certain objects or events. 2. a standard against which experimental observations may be evaluated; see negative c. and positive c. 3. a patient or group differing from that under study (the treated or case group) by lacking the disease or by having a different or absent treatment or regimen; the controls and case or treated subjects usually otherwise have certain similarities to allow or enhance comparison between them. 4. in psychiatry, the process of consciously restraining and regulating impulses and suppressing instincts and affects.