| standard pressure | The absolute pressure to which gases are referred under standard conditions (STPD), i.e., 760 mm Hg, 760 torr, or 101,325 newtons/m2 (i.e., 101,325 Pa). (05 Mar 2000) |
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| standard score | A statistically referenced or derived score representing the deviation of a raw score from its mean in standard deviation units. (05 Mar 2000) |
| standard solution | Standardised solution, a solution of known concentration, used as a standard of comparison or analysis. (05 Mar 2000) |
| standard state | <chemistry> The most stable form of a substance at 298 K and 1 atmosphere of pressure. (09 Jan 1998) |
| standard substance | A pure, authentic substance used for identification purposes. (05 Mar 2000) |
| standard temperature | A temperature of 0캜 or 273.15 |
| standard urea clearance | The value obtained when the square root of the urine flow (when below 2 ml/min) is multiplied by the urine urea concentration and divided by the whole blood urea concentration; represents an old empirical adjustment for the effect of low urine flow on urea excretion; sometimes corrected for body size by dividing by some function of body weight or surface area. Later, plasma concentration was substituted for blood concentration in the calculation. The normal value is about 54 ml/min per 1.73 m2 in an adult person. Synonym: Van Slyke's formula. (05 Mar 2000) |
| standard volume | The volume of an ideal gas at standard temperature and pressure, approximately 22.414 liters. (05 Mar 2000) |
| standard-wing | <zoology> A curious paradise bird (Semioptera Wallacii) which has two long special feathers standing erect on each wing. Source: Websters Dictionary (01 Mar 1998) |
| ICAO standard atmosphere | The standard atmosphere adopted by the International Civil Aviation Organization, used for calibrating altimeters and for expressing hypobaric chamber pressures in terms of equivalent altitude; it ignores many deviations found in nature. (05 Mar 2000) |
| emission standard | This regulatory value is a quantitative limit on the emission or discharge of a potentially toxic substance from a source. The simplest form for regulatory purposes is a uniform emission standard (UES) where the same limit is placed on all emissions of a particular contaminant. (09 Oct 1997) |
| environmental quality standard | This regulatory value defines the maximum concentration of a potentially toxic substance which can be allowed in an environmental compartment, usually air (air quality standard - AQS) or water, over a defined period. (09 Oct 1997) |
| accelerated reaction | A response occurring in a shorter time than expected; the cutaneous manifestations occurring during the period between the second and tenth day following smallpox vaccination; because it is intermediate between a primary reaction and an immediate reaction, it is regarded as evidence of some degree of resistance. Synonym: vaccinoid reaction. (05 Mar 2000) |
| acid reaction | Any test by which an acid reaction is recognised such as the change of blue litmus paper to red, an excess of hydrogen ions over hydroxide ions in aqueous solution indicated by a pH value less than 7 (at 22캜). Compare: dissociation constant of water. (05 Mar 2000) |
| acute-phase reaction | <immunology, rheumatology> Refers to the changes in synthesis of certain proteins within the serum during an inflammatory response, which provides rapid protection for the host against microorganisms via non-specific defense mechanisms. It consists of fever, an increase in inflammatory humoral factors, and an increased synthesis by hepatocytes of a number of proteins or glycoproteins usually found in the plasma; the reaction is mediated by endogenous pyrogens, the hypothalamus, adrenal hormones, and other factors. (12 Jul 2000) |