| alveolar-arterial oxygen difference | The difference or gradient between the partial pressure of oxygen in the alveolar spaces and the arterial blood: P(A-a)02. Normally in young adults this value is less than 20 mm Hg. See: alveolar gas equation. (05 Mar 2000) |
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| arteriovenous carbon dioxide difference | <physiology> The difference in carbon dioxide content (in ml per 100 ml blood) between arterial and venous blood. (05 Mar 2000) |
| arteriovenous oxygen difference | <physiology> The difference in the oxygen content (in ml per 100 ml blood) between arterial and venous blood. (05 Mar 2000) |
| A-V difference | <abbreviation> Arteriovenous difference of concentration of a substance. (05 Mar 2000) |
| brightness difference threshold | The smallest difference that can be perceived as a difference in brightness. Synonym: light difference. (05 Mar 2000) |
| rank-difference correlation | The relationship between paired series of measurements, each ranked according to magnitude, which yields a coefficient known as rho; the value of rho varies from zero (no relationship) to +1.00 (perfect relationship). (05 Mar 2000) |
| cation-anion difference | <biochemistry> The difference between the sum of the measured cations and anions in the plasma or serum calculated as follows: (Na + K) -(Cl + HCO3) = < 20 mmol/l. Elevated values may occur in diabetic or lactic acidosis; normal or low values occur in bicarbonate-losing metabolic acidoses. Synonym: cation-anion difference. (05 Mar 2000) |
| standard error of difference | A statistical index of the probability that a difference between two sample means is greater than zero. (05 Mar 2000) |
| difference | 1. The act of differing; the state or measure of being different or unlike; distinction; dissimilarity; unlikeness; variation; as, a difference of quality in paper; a difference in degrees of heat, or of light; what is the difference between the innocent and the guilty? "Differencies of administration, but the same Lord." (1 Cor. Xii. 5) 2. Disagreement in opinion; dissension; controversy; quarrel; hence, cause of dissension; matter in controversy. "What was the difference? It was a contention in public." (Shak) "Away therefore went I with the constable, leaving the old warden and the young constable to compose their difference as they could." (T. Ellwood) 3. That by which one thing differs from another; that which distinguishes or causes to differ;; mark of distinction; characteristic quality; specific attribute. "The marks and differences of sovereignty." (Davies) 4. Choice; preference. "That now be chooseth with vile difference To be a beast, and lack intelligence." (Spenser) 5. An addition to a coat of arms to distinguish the bearings of two persons, which would otherwise be the same. See Augmentation, and Marks of cadency, under Cadency. 6. <logic> The quality or attribute which is added to those of the genus to constitute a species; a differentia. 7. <mathematics> The quantity by which one quantity differs from another, or the remainder left after subtracting the one from the other. Ascensional difference. See Ascensional. Synonym: Distinction, dissimilarity, dissimilitude, variation, diversity, variety, contrariety, disagreement, variance, contest, contention, dispute, controversy, debate, quarrel, wrangle, strife. Origin: F. Difference, L. Differentia. Source: Websters Dictionary (01 Mar 1998) |
| difference equation | <epidemiology> The mathematical formulation corresponding to a discrete time model. (05 Dec 1998) |
| light difference | The difference in light sensitivity of the two eyes. Synonym: brightness difference threshold. (05 Mar 2000) |
| bone density | Bone density is the amount of bone tissue in a certain volume of bone. It can be measured using a special X-ray called a quantitative computed tomogram. (12 Dec 1998) |
| bulk density | Weight per unit of volume, usually specified in pounds per cubic foot. (05 Dec 1998) |
| buoyant density | The density that allows a substance to float in some standard fluid. (05 Mar 2000) |
| vapor density | The mass per unit volume of a vapor; since the vapor density changes with temperature and pressure, it is commonly expressed as a specific gravity, i.e., the weight of the vapor divided by the weight of an equal volume of a reference gas (e.g., oxygen or hydrogen) at the same temperature and pressure. (05 Mar 2000) |