| standard limb lead | One of the three original bipolar limb lead's of the clinical electrocardiogram, designated I, II and III: lead I records the potential difference between the right and left arms; lead II the difference between right arm and left leg; and lead III the difference between left arm and left leg. Synonym: indirect lead. (05 Mar 2000) |
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| standard operating procedure | <microscopy> A written set of instructions detailing the normal procedures for operating a piece of equipment. WWW: Available online (05 Aug 1998) |
| 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) |
| 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) |