| ecosystem function | The collective intraspecific and interspecific interactions of the biota, such as primary and secondary production and mutualistic relationships. The interactions between organisms and the physical environment, such as nutrient cycling, soil development, water budgeting, and flammability. (09 Oct 1997) |
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| function | The special, normal or proper physiologic activity of an organ or part. Origin: L. Functio, from fungi = to do (18 Nov 1997) |
| function corrector | A removable orthodontic appliance utilizing oral and facial muscle forces to move teeth and possibly change the relationship of the dental arches. (05 Mar 2000) |
| line spread function | A measure of the ability of a system to form sharp images; in radiology, determined by measuring the spatial density distribution on film of the X-ray image of a narrow slit in a dense metal, such as uranium; from this can be calculated the modulation transfer function. (05 Mar 2000) |
| liver function test | <investigation> A test that measures the blood serum level of several enzymes produced by the liver. An elevated liver function test is a sign of possible liver damage. Examples include: prothrombin time, PTT, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, gamma glutamyl transpeptidase, alkaline phosphatase and serum albumin. (14 Oct 1997) |
| lymphocyte function associated antigen | A member of the integrin family that is expressed on all leukocytes and binds to ICAM-1 and ICAM-2 on a variety of cells. (05 Mar 2000) |
| lymphocyte function-associated antigen-1 | A heterodimer molecule widely expressed on cells of haematopoietic origin. Cd11a antigen comprises the alpha chain and the CD18 antigen (antigens, CD18) the beta chain. Lfa-1 is a major receptor of T-cells, B-cells, and granulocytes. It mediates the leukocyte adhesion reactions underlying cytolytic conjugate formation, helper T-cell interactions, and antibody-dependent killing by natural killer cells and granulocytes. Intracellular adhesion molecule-1 (icam-1) has been defined as a ligand for lfa-1. (12 Dec 1998) |
| acoustic impedance tests | Objective tests of middle ear function based on the difficulty (impedance) or ease (admittance) of sound flow through the middle ear. These include static impedance and dynamic impedance (i.e., tympanometry and impedance tests in conjunction with intra-aural muscle reflex elicitation). This term is used also for various components of impedance and admittance (e.g., compliance, conductance, reactance, resistance, susceptance). (12 Dec 1998) |
| Alpha tests | A set of paper and pencil-administered mental tests first used in the United States Army in 1917-1918 to determine the mental ability of literate recruits; the set includes 8 different types of tests: i.e., directions, arithmetical problems, practical judgement, synonyms and antonyms, disarrayed sentences, number series completions, analogies, and information; they are designed especially for testing large groups of individuals simultaneously, and for rapid machine scoring; distinguished from the Army Beta tests, a complementary set for administration to recruits who could not read or write English, in which the instructions are given in signs and the test material is pictorial. See: Beta tests. Synonym: Army Alpha tests. (05 Mar 2000) |
| aptitude tests | Primarily non-verbal tests designed to predict an individual's future learning ability or performance. (12 Dec 1998) |
| Beta tests | <psychiatry> A set of pictorially administered mental tests first used in the United States Army in 1917-1918 to determine the relative mental ability of recruits who were illiterate or deficient in reading and writing English, the instructions being given in signs and the test material's pictorial in characters; distinguished from the Army Alpha tests, which were administered at the same time to literate recruits. Synonym: Army Beta tests. (05 Mar 2000) |
| blood coagulation tests | Laboratory tests for evaluating the individual's clotting mechanism. (12 Dec 1998) |
| breath tests | Any tests done on exhaled air. (12 Dec 1998) |
| bronchial provocation tests | Tests involving inhalation of allergens (nebulised or in dust form), nebulised pharmacologically active solutions (e.g., histamine, methacholine), or control solutions, followed by assessment of respiratory function. These tests are used in the diagnosis of asthma. (12 Dec 1998) |
| caloric tests | Elicitation of a rotatory nystagmus by stimulating the saemicircular canals with water or air which is above or below body temperature. In warm caloric stimulation a rotatory nystagmus is developed toward the side of the stimulated ear; in cold, away from the stimulated side. Absence of nystagmus indicates the labyrinth is not functioning. (12 Dec 1998) |