| AFF | atrial fibrillation; atrial filling fraction; atrial flutter |
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| RA | radioactive; ragocyte; ragweed antigen; rapidly adapting [receptors]; reactive arthritis; reciprocal... |
| RH | radiant heat; radiation hybrid; radiological health; reactive hyperemia; recurrent herpes; regulator... |
| RS | radioscaphoid; random sample; rating schedule; Raynaud syndrome; recipient's serum; rectal sinus; re... |
| RUL | right upper eyelid; right upper lateral; right upper limb; right upper lobe |
| modulation transfer function | <microscopy> A mathematical function that expresses the ability of an optical or electronic device to transfer signals faithfully as a function of the spatial or temporal frequency of the signal. The modulation transfer function is the ratio of percentage modulation of a sinusoidal signal leaving to that entering the device over the range of frequencies of interest. The modulation transfer function is usually presented as a graph of modulation transfer function versus log (frequency). For a square wave signal, the function is known as the CTF. Acronym: MTF (26 Mar 1998) |
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| placental function tests | Methods used for the assessment of placental function. (12 Dec 1998) |
| platelet function disorders | <haematology> Platelet function can be affected by a number of different disease processes including polycythaemia vera, leukaemia, myelofibrosis, renal failure, multiple myeloma and some medications (for example penicillins, salicylates, phenothiazines). Disturbed blood clotting can be manifested by: easy bruising, bleeding gums, nosebleeds, abnormal vaginal bleeding, rectal bleeding, skin rash, vomiting blood, coughing up blood or blood in the urine. A measure of bleeding time and coagulation profile will be part of the evaluation. (31 Dec 1997) |
| contrast transfer function | <microscopy> A mathematical function that expresses the ability of an optical or electronic device to transfer signals faithfully as a function of the spatial or temporal frequency of the signal. The modulation transfer function is the ratio of percentage modulation of a sinusoidal signal leaving to that entering the device over the range of frequencies of interest. The modulation transfer function is usually presented as a graph of modulation transfer function versus log (frequency). For a square wave signal, the function is known as the CTF. Acronym: MTF (26 Mar 1998) |
| point-spread function | <microscopy> The mathematical representation of the image of a point source. For a diffraction-limited optical system operating in the absence of aberrations, the point-spread function is the Airy disk. See: three-dimensional diffraction pattern. (05 Aug 1998) |
| hepatic function impairment | The impaired ability of the liver to fulfill its role in metabolism. (27 Sep 1997) |
| split renal function test | A study performed to determine various functional parameters of one kidney compared to the contralateral kidney; ureteral catheters are inserted at cystoscopy into the ureter or renal pelvis bilaterally, and simultaneous measurements are made of urine flow rate, insulin, or PAH (if infused), endogenous creatinine, or various urinary solutes. Synonym: differential renal function test, split renal function test. (05 Mar 2000) |
| state function | <chemistry> A property that is independent of the pathway, this function can be used to define or specify the state of the system. (09 Jan 1998) |
| differential renal function test | A study performed to determine various functional parameters of one kidney compared to the contralateral kidney; ureteral catheters are inserted at cystoscopy into the ureter or renal pelvis bilaterally, and simultaneous measurements are made of urine flow rate, insulin, or PAH (if infused), endogenous creatinine, or various urinary solutes. Synonym: differential renal function test, split renal function test. (05 Mar 2000) |
| discriminant function | A particular combination of continuous variable test results designed to achieve separation of groups; e.g., a single number representing a combination of weighted laboratory test results designed to discriminate between clinical classes. (05 Mar 2000) |
| distribution function | <radiobiology> Function characterising the density of particles located at a given point in phase space (a combination of velocity and/or position coordinates) at a given time. The velocity-space distribution function gives the number of particles with a particular velocity, the position-space distribution function is synonymous with the particle density in position-space. Different combinations of position and spatial coordinates are useful in different problems. (09 Oct 1997) |
| isomeric function | The individual function of an isolated segment of the spinal cord. (05 Mar 2000) |
| optical transfer function | <microscopy> The relationship between the image produced by an optical instrument and the amplitude and phase of a periodic specimen, measured at various spatial frequencies. The optical transfer function curve, which shows how well contrast is maintained for finer specimen details, is a complex function, of which the real term gives the ratio of amplitudes, and the imaginary term the phase relationships. When the brightness of the periodic specimen varies as a sine wave, the modulus or absolute value of the optical transfer function becomes the modulation transfer function, when the brightness varies as a square wave, the modulation transfer function is known as a contrast transfer function. Acronym: OTF (26 Mar 1998) |
| ovarian function tests | Methods used for assessment of ovarian function. (12 Dec 1998) |
| 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) |