activity

activity /ac·tiv·i·ty/ (ak-tiv´i-te)

1. the quality or process of exerting energy or of accomplishing an effect.

2. a thermodynamic quantity that represents the effective concentration of a solute in a nonideal solution. Symbol .

3. the number of disintegrations per unit time of a radioactive material. Symbol .

4. the presence of recordable electrical energy in a muscle or nerve (electrical a.).

5. optical a.

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end-plate activity  spontaneous activity recorded close to motor end plates in normal muscle.

enzyme activity  the catalytic effect exerted by an enzyme, expressed as units per milligram of enzyme (specific a.) or as molecules of substrate transformed per minute per molecule of enzyme (molecular a.) .

intrinsic sympathomimetic activity  (ISA) the ability of a ß-blocker to stimulate ß-adrenergic receptors weakly during ß-blockade.

optical activity  the ability of a chemical compound to rotate the plane of polarization of plane-polarized light.

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ac·tiv·i·ty (k-tv-t)

n.

1. A physiological process.

2. The presence of neurogenic electrical energy in electroencephalography.

3. An ideal concentration for which the law of mass action will apply perfectly.

4. The intensity of a radioactive source.

5. The ability to take part in a chemical reaction.

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activity,

n 1. the modification brought about by a remedy in a living organism.
2. the ability of a medicine to bring about modification in a living organism. See also drug action, reactivity, and receptivity.

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activity

the quality or process of releasing energy or of accomplishing an effect.

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displacement activity

an instinctive behavior pattern, exhibited out of context and believed to be a means of relieving tension in the animal. Usually performed when the animal is in a state of high arousal or when it is frustrated in the performance of some instinctive activity. Seen as sexual mounting, digging, tail chasing, or excessive grooming in cats.

economic activity

a method of producing a specific product, e.g. fine wool, white veal.

enzyme activity

the catalytic effect exerted by an enzyme, expressed as units per milligram of enzyme (specific activity) or molecules of substrate transformed per minute per molecule of enzyme (molecular activity).

activity gross income

the total value of production, rather than the income, for a particular activity.

activity gross margin

the gross income of an activity less its variable costs.

intermediate activity

production of a commodity which is not sold but is used as an input to some other enterprise, e.g. crop used on the farm as stock feed.

optical activity

the ability of a chemical compound to rotate the plane of polarization of plane-polarized light.