| thermal sense | The ability to distinguish differences of temperature. Synonym: temperature sense, thermal sense, thermic sense, thermesthesia. Origin: thermo-+ G. Aisthesis, sensation (05 Mar 2000) |
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| thermal sensors | Sensors that detect tiny changes in heat or temperature. (14 Nov 1997) |
| thermal spectrum | The part of the invisible spectrum of wave length just longer than that of visible red light. Synonym: thermal spectrum. (05 Mar 2000) |
| thermal velocity | <radiobiology> Average speed (magnitude of velocity) of a particle at a given temperature (in a Maxwellian velocity distribution). (09 Oct 1997) |
| acid-base equilibrium | A condition in which the net rate of acid or alkali production by the body is balanced by the net rate of acid or alkali excretion from the body, resulting in a stable concentration of hydrogen ions in the body fluids. (12 Dec 1998) |
| radioactive equilibrium | <radiobiology> That condition in which the activities of the members of a radioactive chain decrease exponentially in time with the half-life of the chain precursor. Such radioactive equilibrium is only possible when the half-life of the precursor is longer than that of any other chain member. If the precursor half-life is so long that the change in the precursor population during the period of interest can be ignored, all the activities become sensibly equal and the equilibrium is said to be secular, otherwise it is said to be transient. (16 Dec 1997) |
| random mating equilibrium | <genetics> In a population containing the genotypes of AA, aa, and Aa, the frequency of AA will be p2, the frequency of aa will be q2, and the frequency of Aa will be 2 pq at equilibrium, where p is the frequency of A and q is the frequency of a. By the Hardy-Weinberg law, a ramdonly-mating population will eventually reach these frequencies and be at this equilibrium as long as there are no selection pressures on the population. (09 Oct 1997) |
| genetic equilibrium | A condition in which the rate of an allele's forward mutation is cancelled out by its rate of reverse mutation. (09 Oct 1997) |
| Gibbs-Donnan equilibrium | An equilibrium established between a charged, immobile colloid (such as clay, ion exchange resin or cytoplasm) and a solution of electrolyte. Characteristics: ions of like charge to the colloid tend to be excluded, ions of opposite charge tend to be attracted, the colloid compartment is electrically polarized relative to the solution in the same direction as the colloid charges (a Donnan potential) and the osmotic pressure is higher in the colloid compartment. (18 Nov 1997) |
| chemical equilibrium | <chemistry> A state in a reversible chemical reaction at which the reactants are turning into products at the same rate as the products are turning back into the reactants, so that the amounts of each reactant and product remains constant. (09 Oct 1997) |
| physiologic equilibrium | nutritive equilibrium |
| Hardy-Weinberg equilibrium | <genetics> In a population containing the genotypes of AA, aa, and Aa, the frequency of AA will be p2, the frequency of aa will be q2, and the frequency of Aa will be 2 pq at equilibrium, where p is the frequency of A and q is the frequency of a. By the Hardy-Weinberg law, a ramdonly-mating population will eventually reach these frequencies and be at this equilibrium as long as there are no selection pressures on the population. (09 Oct 1997) |
| secular equilibrium | A type of radioactive equilibrium in which the half-life of the precursor (parent) radioisotope is so much longer than that of the product (daughter) that the radioactivity of the daughter becomes equal to that of the parent with time. Stable equilibrium, equilibrium in which, after every small perturbation, the original state will tend to be restored. Transient equilibrium, a type of radioactive equilibrium in which the half-life of the parent radioisotope is longer than that of the daughter so that the ratio of activities of parent and daughter become constant as they decrease with time. Unstable equilibrium, equilibrium in which the response to a small perturbation will tend to make the perturbation greater (e.g., a logged feedback process of zero order). (05 Mar 2000) |
| homeostatic equilibrium | See: homeostasis. Nitrogenous equilibrium, a condition in which the amount of nitrogen excreted from the body equals that taken in with the food; nutritive equilibrium so far as protein is concerned. Nutritive equilibrium, condition in which there is a perfect balance between intake and excretion of nutritive material, so that there is no increase or loss in weight. Synonym: physiologic equilibrium. (05 Mar 2000) |
| sense of equilibrium | The sense that makes possible a normal physiologic posture. Synonym: static sense. (05 Mar 2000) |