| acoustic reference level | The biological reference level for sound measurements. When the term decibel is used to indicate the noise level, a reference quantity is implied; this reference value is usually expressed as a sound pressure of 20 micronewtons per square meter. The reference level is referred to as 0 decibels, the baseline of the scale of noise level's; this baseline is considered the weakest sound that can be heard by a person with very good hearing in an extremely quiet location. Other equivalent reference level's still being used include 0.0002 microbar and 0.0002 dyne per square centimeter. (05 Mar 2000) |
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| reference | The act of referring or consulting, something that refers to something else. (18 Nov 1997) |
| reference books | Books designed by the arrangement and treatment of their subject matter to be consulted for definite terms of information rather than to be read consecutively. Reference books include dictionaries, encyclopedias, atlases, etc. (12 Dec 1998) |
| reference books, medical | Books in the field of medicine intended primarily for consultation. (12 Dec 1998) |
| reference electrode | An electrode expected to have a constant potential, such as a calomel electrode, and used with another electrode to complete an electrical circuit through a solution; e.g., when a reference electrode is used with a glass electrode for pH measurement, changes in voltage between the two electrode's can be attributed to the effects of pH on the glass electrode alone. (05 Mar 2000) |
| reference method | An analytical procedure sufficiently free of random or systematic error to make it useful for validating proposed new analytical procedures for the same analyte. (05 Mar 2000) |
| reference standards | A basis of value established for the measure of quantity, weight, extent or quality, e.g. Weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy. (12 Dec 1998) |
| reference values | The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality. (12 Dec 1998) |
| physicians' desk reference | This thick volume the 1998 pdr runs 3,223 pages in length is a guide to all the prescription drugs available in the united states. Although not exactly redcommended fare for bedtime reading, the pdr is a key reference to the american pharmacopeia. It is available in many bookstores in the u.s. (12 Dec 1998) |
| planes of reference | Plane's which act as a guide to the location of other plane's. (05 Mar 2000) |
| hexaxial reference system | The figure resulting if the lines of derivation of the unipolar limb leads of the electrocardiogram are added to the triaxial reference system. (05 Mar 2000) |
| delusion of reference | A delusional idea that external events, etc., refer to the self. (05 Mar 2000) |
| idea of reference | The misinterpretation that other people's statements or acts or neutral objects in the environment are directed toward one's self when, in fact, they are not. (05 Mar 2000) |
| triaxial reference system | The figure resulting from rearranging the lines of derivation of the three standard limb leads of the electrocardiogram (as represented in Einthoven's triangle) so that, instead of forming the sides of an equilateral triangle, they bisect one another. Synonym: Dieuaide diagram. (05 Mar 2000) |
| Abbe test plate | <equipment> A long, wedge-shaped coverslip about 0.20 mm thick at one end and 0.10 to 0.12 mm at the other end coated chemically with a silver film on which are ruled horizontal lines. at each variation in thickness of 0.01 mm there are vertical lines. By means of oblique illumination and by focusing on different portions of the plate, it is possible to determine the optimum coverslip thickness for any objective and also, for microscopes with drawtubes, the tube length for best objective performance. The approximate freedom from spherical and chromatic aberrations can also be estimated. Small isolated bits of silver near the edges of the lines form good objects for the star test (05 Aug 1998) |