| intermediate trait | A measurable trait in which there is some evidence of the operation of a simple major cause, but in which the variation within the putative categories is such as to cause overlap and hence ambiguity in classification of any particular reading. (05 Mar 2000) |
|---|---|
| trait | A qualitative characteristic; a discrete attribute as contrasted with metrical character. A trait is amenable to segregation rather than quantitative analysis; it is an attribute of phenotype, not of genotype. Origin: Fr. From L. Tractus, a drawing out, extension (05 Mar 2000) |
| liminal trait | A trait that falls into natural groups that originate not in categorically distinct causes but in whether or not the outcome attains critical values; e.g., gallstones may result from a categorical cause or from unusual levels of causal factors that themselves show no evidence of grouping. Synonym: liminal trait. (05 Mar 2000) |
| absolute intensity threshold acuity | The minimal light that can be seen. (05 Mar 2000) |
| absolute threshold | The lowest limit of any perception whatever. Compare: differential threshold. Synonym: stimulus threshold. (05 Mar 2000) |
| achromatic threshold | Threshold of visual sensation, the minimal light intensity evoking a visual sensation. Synonym: achromatic threshold, minimum light threshold. (05 Mar 2000) |
| anaerobic threshold | The oxygen consumption level above which aerobic energy production is supplemented by anaerobic mechanisms during exercise, resulting in a sustained increase in lactate concentration and metabolic acidosis. The anaerobic threshold is affected by factors that modify oxygen delivery to the tissues; it is low in patients with heart disease. Methods of measurement include direct measure of lactate concentration, direct measurement of bicarbonate concentration, and gas exchange measurements. (12 Dec 1998) |
| auditory threshold | The audibility limit of discriminating sound intensity and pitch. (12 Dec 1998) |
| brightness difference threshold | The smallest difference that can be perceived as a difference in brightness. Synonym: light difference. (05 Mar 2000) |
| pain threshold | Amount of stimulation required before the sensation of pain is experienced. (12 Dec 1998) |
| galvanic threshold | The minimal strength of an electrical stimulus of indefinite duration that is able to cause excitation of a tissue, e.g., muscle or nerve. See: chronaxie. Synonym: galvanic threshold. Origin: rheo-+ G. Basis, a base (05 Mar 2000) |
| relational threshold | The smallest degree of difference between two stimuli that permits them to be perceived as different. (05 Mar 2000) |
| visual threshold | Threshold of visual sensation, the minimal light intensity evoking a visual sensation. Synonym: achromatic threshold, minimum light threshold. (05 Mar 2000) |
| renal threshold | Concentration of plasma substance above which the substance appears in the urine. (05 Mar 2000) |
| phenotypic threshold | A quantitative genetic trait with a continuous distribution termed its liability may generate two kinds of phenotype, according to whether the liability lies above or below some critical threshold at about which a radical change in behaviour occurs. For instance, blood uric acid level is a liability with an approximately gaussian distribution. At a critical point of chemical saturation (the threshold crystallization occurs and the resulting gout or nongout is a threshold trait. (05 Mar 2000) |