| second-stability region | <radiobiology> A high pressure region where the plasma becomes stable to the pressure-gradient-driven ballooning instability. The plasma is stable in the limit of small pressure gradients, becomes unstable at some intermediate pressure, and then becomes stable again at still higher pressures. Tokamaks operating in the second-stability region would be more attractive because the higher pressures (beta) would provide more fusion reactivity per unit volume of plasma, allowing smaller reactors to be built. (09 Oct 1997) |
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| second stage of labour | <obstetrics> The part of labour from the full dilatation of the cervix until the baby is completely out of the birth canal. The second stage of labour is also called the stage of expulsion. (12 Dec 1998) |
| second temporal convolution | A longitudinal gyrus on the lateral surface of the temporal lobe, between the superior and inferior temporal sulci. Synonym: gyrus temporalis medius, middle temporal convolution, second temporal convolution. (05 Mar 2000) |
| second tibial muscle | An inconstant muscle, of small size, arising from the back of the tibia and inserted into the articular capsule of the ankle joint. Synonym: second tibial muscle. (05 Mar 2000) |
| second tooth | One of the 32 teeth belonging to the second or permanent dentition; eruption of the permanent teeth begins from the fifth to the seventh year, and is not completed until the seventeenth to the twenty-third year, when the last of the wisdom teeth appears. Synonym: dens permanens, dens succedaneus, second tooth, secondary dentition, succedaneous dentition, succedaneous tooth. (05 Mar 2000) |
| neoplasms, second primary | Abnormal growths of tissue that follow a previous neoplasm but are not metastases of the latter. The second neoplasm may have the same or different histological type and can occur in the same or different organs as the previous neoplasm but in all cases arises from an independent oncogenic event. The development of the second neoplasm may or may not be related to the treatment for the previous neoplasm since genetic risk or predisposing factors may actually be the cause. (12 Dec 1998) |
| error of the second kind | See: Error, beta. (12 Dec 1998) |
| twelfth-second | <physics> A unit for the measurement of small intervals of time, such that 10^12 (ten trillion) of these units make one second. Source: Websters Dictionary (01 Mar 1998) |
| foot-pound-second | <unit> An absolute unit of the foot-pound-second system. (05 Mar 2000) |
| foot-pound-second system | <mechanics> A system of absolute units based on the foot, pound, and second. (05 Mar 2000) |
| alveolocapillary block | The presence of material that impairs the diffusion of gases between the air in the alveolar spaces and the blood in alveolar capillaries; block can be caused by oedema, cellular infiltration, fibrosis, or tumour, and results in undersaturation of peripheral arterial blood with oxygen. (05 Mar 2000) |
| anterograde block | Conduction block of an impulse traveling anywhere in its ordinary direction, for example, from the sinoatrial node toward the ventricular myocardium. (05 Mar 2000) |
| arborization block | Intraventricular block supposedly due to widespread blockage in the Purkinje ramifications and manifested in the electrocardiogram by a pattern similar to bundle-branch block but with complexes of low amplitude. (05 Mar 2000) |
| atrioventricular block | <cardiology> A conduction disturbance that results in the inappropriate delay (or complete inability) of a electrical impulse, generated in the atria, to reach the ventricles (via the atrioventricular node). Clinical types are divided into first (nonserious), second and third degree (most serious). Some drugs may precipitate atrioventricular block (for example clonidine, methyldopa, verapamil). A permanent pacemaker may be required for a third degree (complete) heart block. (02 Jan 1998) |
| autonomic nerve block | Interruption of sympathetic pathways, by local injection of an anaesthetic agent, at any of four levels: peripheral nerve block, sympathetic ganglion block, extradural block, and subarachnoid block. (12 Dec 1998) |