| time of flight | The time for a photon created by annihilation of a positron-electron pair to reach a detector; since annihilation photons are created in pairs and travel in opposite directions at about 3 × 1010 cm/sec, measurement of the difference in arrival time at detectors with sub-nanosecond resolution allows calculation of the location of the event; the basic physics of positron emission tomography. (05 Mar 2000) |
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| time perception | The ability to estimate periods of time lapsed or duration of time. (12 Dec 1998) |
| time sense | The faculty by which the passage of time is appreciated. (05 Mar 2000) |
| time-varied gain | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| time-varied gain control | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| tissue thromboplastin inhibition time | A test used to identify lupus anticoagulant; the thromboplastin source used in the prothrombin test is diluted to increase sensitivity to inhibitors. (05 Mar 2000) |
| energy confinement time | <radiobiology> Characteristic time in which 1/e (or sometimes 1/2) of a system's energy is lost to its surroundings. In a plasma device, the energy loss time (or the energy confinement time) is one of three critical parameters determining whether enough fusion will occur to sustain a reaction. See: Lawson criterion. (09 Oct 1997) |
| energy replacement time | <radiobiology> Time required for a plasma to lose (via radiation or other loss mechanisms) an amount of energy equal to its average kinetic energy. (09 Oct 1997) |
| euglobulin clot lysis time | A measure of the ability of plasminogen activators and plasmin to lyse a clot; normally, clot lysis is determined by the balance of factors which activate fibrinolysis (plasminogen activators and plasmin) and those which inhibit lysis; in certain conditions (e.g., carcinoma or hepatic insufficiency) activating factors predominate and can be measured by noting the time it takes the euglobulin fraction of plasma (excluding inhibitors of fibrinolysis) to clot. (05 Mar 2000) |
| fading time | The time required for a constant stimulus applied to a fixed area of the peripheral visual field to stop. (05 Mar 2000) |
| zero time-binding DNA | DNA that has become the duplex form at the start of a reassociation process. Acronym: DNA (05 Mar 2000) |
| utilization time | The minimum duration of a stimulus of rheobasic strength that is just sufficient to produce excitation. Synonym: temps utile. (05 Mar 2000) |
| forced expiratory time | The time taken to expire a given volume or a given fraction of vital capacity during measurement of forced vital capacity; subscripts specify the exact parameters measured. (05 Mar 2000) |
| left ventricular ejection time | The time measured clinically from onset to incisural notch of the carotid or other pulse; properly the time of ejection of blood from the left ventricle beginning with aortic valve opening and ending with aortic valve closure. (05 Mar 2000) |