| hazard rate | <statistics> Theoretical measure of the risk of occurrence of an event, e.g., death, new disease, at a point in time. (05 Mar 2000) |
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| heart rate | The number of beats per minute. Normal resting heart rates are variable with age, sex, size and overall cardiovascular condition. Heart rate can be determined by taking the pulse. Normal heart rate for an average sized adult is in the range of 60-85 beats/minute. (27 Sep 1997) |
| heart rate, foetal | The heart rate of the foetus. The normal range at term is between 120 and 160 beats per minute. (12 Dec 1998) |
| heat rate | The amount of fuel energy required by a power plant to produce one kilowatt-hour of electrical output. A measure of generating station thermal efficiency, generally expressed in Btu per net kWh. It is computed by dividing the total Btu content of fuel burned for electric generation by the resulting net kWh generation. (05 Dec 1998) |
| scan rate | <microscopy> The number of horizontal-scan lines per frame and vertical scans per second that are repeated in video, for example, 525/60, 625/50. In 525/60, 2: 1 interlaced video, the V scan is repeated at the field rate (which is half of the frame rate for 2: 1 interlaced video) so that 525 H scans take place 30 times a second. The H-scan rate is therefore 525 x 30 = 15.75 kHz. With 525/60, 1: 1 interlace, the H-scan rate would be twice this value. (05 Aug 1998) |
| secretory rate | The amount of a substance secreted by cells or by a specific organ or organism over a given period of time; usually applies to those substances which are formed by glandular tissues and are released by them into biological fluids, e.g., secretory rate of corticosteroids by the adrenal cortex, secretory rate of gastric acid by the gastric mucosa. (12 Dec 1998) |
| sedimentation rate | A sedimentation rate, or sed rate , is a blood test that detects and monitors inflammation activity. It is measured by recording the rate at which red blood cells (rbcs) sediment in a tube over time. It increases (the rbcs sediment faster) with more inflammation. (12 Dec 1998) |
| shear rate | The change in velocity of parallel planes in a flowing fluid separated by unit distance; its units expressed in seconds-1. (05 Mar 2000) |
| slew rate | In electronic pacemaker function, the maximum rate of change of an amplifier output voltage; important variable affecting heart function as controlled by an electronic pacemaker. Sensing circuits in the pacemaker often respond to the slew rate rather than to the absolute amplitude of the voltage pulse. (05 Mar 2000) |
| steady-state rate | The velocity of an enzyme-catalyzed reaction in which, over the time course of the study, the concentration of any enzyme species is constant (i.e., for an enzyme-substrate binary complex, ES, d[ES]/dt&apprxeq;00; for this to hold true, the total enzyme concentration must be much less than the initial substrate concentration. Synonym: steady-state rate. (05 Mar 2000) |
| neonatal mortality rate | The number of children dying under 28 days of age divided by the number of live births that year. The neonatal mortality rate in the united states, which was 8.4 per 1,000 live births in 1980, declined to 5.8 per 1,000 live births in 1990. (12 Dec 1998) |
| steroid metabolic clearance rate | A measure of the rate of metabolism of a given steroid within the body, usually expressed as liters of body fluid that contain the amount of steroid metabolised per day. (05 Mar 2000) |
| steroid production rate | The total quantity of a given steroid formed in the body, usually expressed as milligrams per day; represents the sum of the glandular secretion of the steroid and extraglandular formation of it from various steroid precursors. (05 Mar 2000) |
| steroid secretory rate | The rate of glandular secretion of a given steroid, usually expressed as milligrams per day; does not include any amount of the steroid that might be formed extraglandularly. (05 Mar 2000) |
| stillbirth rate | The number of foetal deaths divided by the sum of live births and foetal deaths occurring in the same population during the same time period. Synonym: stillbirth rate. (05 Mar 2000) |