effect /ef·fect/ (ĕ-fekt´) the result produced by an action.
effect,
effect [ĕ-fekt´]
Anrep effect abrupt elevation of aortic pressure results in a positive inotropic effect, augmented resistance to outflow in the heart.
Bayliss effect increased perfusion pressure and subsequent stretch of vascular smooth muscle causes muscle contraction and increased resistance, which returns blood flow to normal in spite of the elevated perfusion pressure.
Bohr effect increase of carbon dioxide in blood causes decreased affinity of hemoglobin for oxygen.
Doppler effect the relationship of the apparent frequency of waves, as of sound, light, and radio waves, to the relative motion of the source of the waves and the observer, the frequency increasing as the two approach each other and decreasing as they move apart.
experimenter effects demand characteristics.
Haldane effect increased oxygenation of hemoglobin promotes dissociation of carbon dioxide.
position effect in genetics, the changed effect produced by alteration of the relative positions of various genes on the chromosomes.
pressure effect the sum of the changes that are due to obstruction of tissue drainage by pressure.
side effect a consequence other than that for which an agent is used, especially an adverse effect on another organ system.
Somogyi effect a rebound phenomenon occurring in diabetes: overtreatment with insulin induces hypoglycemia, which initiates the release of epinephrine, ACTH, glucagon, and growth hormone, which stimulate lipolysis, gluconeogenesis, and glycogenolysis, which, in turn, result in a rebound hyperglycemia and ketosis.
ef·fect ( -f kt )n. 1. Something brought about by a cause or an agent; a result. 2. The power to produce an outcome or achieve a result; influence. 3. A scientific law, hypothesis, or phenomenon. 4. The condition of being in full force or execution. 5. Something that produces a specific impression or supports a general design or intention. v. 1. To bring into existence. 2. To produce as a result. 3. To bring about. ef·fect i·ble adj. |
effect,
the result of an agent or cause.
effect [ĕ-fekt´]
a result produced by an action.
additive effect the combined effect produced by the action of two or more agents, being equal to the sum of their separate effects.
adverse effect a symptom produced by a drug or therapy that is injurious to the patient.
Bainbridge effect Bainbridge reflex.
Bohr effect decreased affinity of hemoglobin for oxygen caused by an increase of carbon dioxide; the oxyhemoglobin dissociation curve is displaced to the right because of higher partial pressure of carbon dioxide and lower pH. See also Haldane effect.
The Bohr effect causing a shift to the right in the oxyhemoglobin dissociation curve.
Crabtree effect the inhibition of oxygen consumption on the addition of glucose to tissues or microorganisms having a high rate of aerobic glycolysis; the converse of the Pasteur effect.
cumulative effect the action of a drug or treatment resulting from repeated use.
Doppler effect see doppler effect.
experimenter e's demand characteristics.
extrapyramidal e's the side effects caused by neuroleptic medications, including dystonias, parkinsonism, akathisia, and tardive dyskinesia.
Haldane effect increased oxygenation of hemoglobin promotes dissociation of carbon dioxide; see also Bohr effect.
Hawthorne effect a psychological response in which the subjects in a research study change their behavior simply because they are subjects in a study, not because of the research treatment.
heel effect variation in x-ray beam intensity and projected focal spot size along the long axis of the x-ray tube from cathode to anode.
parallax effect the position of the image on each emulsion of dual emulsion film; it is accentuated by tube-angled x-ray techniques.
Pasteur effect the decrease in the rate of glycolysis and the suppression of lactate accumulation by tissues or microorganisms in the presence of oxygen.
photoelectric effect ejection of electrons from matter as a result of interaction with photons from high frequency electromagnetic radiation, such as x-rays; the ejected electrons may be energetic enough to ionize multiple additional atoms.
placebo effect the total of all nonspecific effects, both good and adverse, of treatment; it refers primarily to psychological and psychophysiological effects associated with the caregiver-patient relationship and the patient's expectations and apprehensions concerning the treatment. See also placebo.
position effect in genetics, the changed effect produced by alteration of the relative positions of various genes on the chromosomes.
pressure effect the sum of the changes that are due to obstruction of tissue drainage by pressure.
proarrhythmic effect any new, more advanced form of arrhythmia caused by an antiarrhythmic agent, especially those that produce hemodynamically important symptoms. These arrhythmias occur less than 30 days after initiation of treatment and are not due to a new event such as acute myocardial infarction or hypokalemia.
side effect a consequence other than that for which an agent is used, especially an adverse effect on another organ system.
Somogyi effect see somogyi effect.
effect,
n the result of an action.
effect, heel (anode heel effect),
n the variation of intensity over the cross section of a useful radiographic beam, caused by the angle at which radiographs emerge from beneath the surface of the focal spot, which causes a differential attenuation of photons composing the useful beam.
effect of external radiation on bone,
n See osteoradionecrosis.
effect of function on bone,
n See law, Wolff's.
effect, photoelectric,
n the process by which radiographic images are produced when the energy of an incident photon is absorbed as the result of bound electron ejection.
effect, wedging,
n an effect produced by food impaction that forces the teeth apart.
effect
a result produced by an action. The relationship between the two can be expressed in linear form. The total association between them may be the sum of a number of effects. The effect may be direct when it is exerted without being transmitted through intervening factors, or indirect when it is. It may also be a spurious effect when the observed changes are due to causes and correlations common to both.
additive effect
the combined effect produced by the action of two or more agents, being equal to the sum of their separate effects.
Coolidge effect
the stimulation of sexual behavior in a male animal upon exposure to a new female.
cumulative effect
cumulation action.
experimenter e's
demand characteristics; the characteristics supplied by the experimental subject in response to what it perceives are the demands of the experimenter.
effect modifier
a factor which modifies the effect of a causal factor under study. Called also interaction.
position effect
in genetics, the changed effect produced by alteration of the relative positions of various genes on the chromosomes.
pressure effect
the sum of the changes that are due to obstruction of tissue drainage by pressure.
side effect
a consequence other than that for which an agent is used, especially an adverse effect on another organ system.
sunburst appearance, effect
calcified streaks which appear on radiographs to radiate from a primary lesion at the surface of a bone. One possible feature of osteogenic sarcoma but can also occur in cases of osteomyelitis.
effect
The result of an action or condition.
Aubert's effect See Aubert's phenomenon.
Bezold-Brücke effect See Bezold-Brücke phenomenon.
Broca-Sulzer effect The brightness produced by a flash of a given luminance depends upon its duration. It is maximum for durations around 30-40 ms when the flash luminance is photopic.
Brücke-Bartley effect An increased brightness produced by an intermittent light source (usually around 8-10 Hz) compared to the same light source viewed in steady illumination. Syn. brightness enhancement.
Cheshire cat effect A form of binocular rivalry in which a moving object seen by one eye can cause the entire image, or parts of the image, of a stationary object seen by the other eye to disappear. The effect can be observed by dividing the field of vision with a mirror placed edge-on in front of the nose at a slight angle. One eye looks straight at a stationary object, such as a sleeping cat, while the other eye sees a reflection through the mirror of a white wall or background. If a hand is waved on the mirror side in the region of the field where the cat is seen, the whole cat or part of it may be seen to disappear. See retinal rivalry.
Craik-O'Brien-Cornsweet effect A phenomenon in which the brightness of an area on one side of a transition strip appears greater than the brightness of the area on the other side of the strip, although both areas outside the transition strip have exactly the same luminance. The transition strip consists of two opposing luminance gradients that meet along a linear edge (called Cornsweet edge); on one side the luminance gradually increases to the edge and on the other side the luminance gradually decreases to the edge. The area adjoining the gradient of increasing luminance appears brighter than the area adjoining the gradient of decreasing luminance. One possible explanation is that the edge information predominates and the visual system and brain 'fill-in' the area next to it to construct a higher brightness percept. Note: by covering the transition strip it is easy to confirm that the two areas have the same luminance. Syn. Craik-O'Brien-Cornsweet illusion; Cornsweet illusion.
crowding effect See crowding phenomenon.
differential prismatic effect The difference in prism power induced by a pair of ophthalmic lenses of different power when the eyes look in various directions of gaze (except through the optical centres). Large amounts of differential prismatic effect can hinder fusion and give rise to diplopia. Example: A patient's right eye is corrected by +5 D, the left eye by +2 D. When the eye rotates upward so that the visual axes intersect the lenses 1 cm above the optical centres, the induced prism power becomes 5 Δ base down on the right and 2 Δ base down on the left. The differential prismatic effect is 3 Δ base down in front of the right eye, probably too large for fusion to be maintained. Syn. prismatic imbalance; relative prismatic effect. See anisophoria; Prentice's law.
Gelb effect In a faintly illuminated room a piece of black paper (or a rotating black disc) is illuminated by a high intensity projector. The beam of the projector falls exactly on the area of the black surface. The paper or disc will then appear to be white. A reversal of the perception is accomplished by placing a small piece of white paper near the disc in front of the projected light, at which time the paper or disc reappears in its true colour, i.e. black.
kinetic depth effect An impression of a three-dimensional structure of a moving two-dimensional shadow cast by a three-dimensional object. It is most easily demonstrated by casting a shadow onto a translucent screen.
Mandelbaum effect A tendency for the accommodative response to be altered when interposing a conflicting visual stimulus to the one being viewed. If the eyes are viewing a distant object through a dirty window or a wire fence, the actual accommodative response will tend to be raised. If the eyes are viewing a near object in front of a dirty window or wire fence the actual accommodative response will be less than if there were no conflicting stimulus.
McCollough effect A visual after-effect of colour that is seen when viewing, for a minute at least, two differently oriented and differently coloured gratings, such as a vertical grating with blue and black stripes and a horizontal grating with orange and black stripes. After adapting to these the subject looks at a figure containing a grating of vertical black and white stripes and a grating of black and white horizontal stripes of the same size as the original coloured gratings. The white stripes will then appear to be of the complementary colour, that is, the vertical stripes appear pinkish and the horizontal stripes appear bluish.
moiré effect An illusory shimmering movement produced by moving one pattern superimposed on another pattern very similar to it. The phenomenon occurs because parts of the periodic patterns are in phase in some locations, and out of phase in other locations. Examples: passing by a set of railings; if a transilluminated square wave grating is superimposed on an identical grating but cross each other at an angle of less than 45º, moiré fringes will appear at the intersections. Syn. moiré pattern. See Toposcope.
oblique effect In central vision, contours with oblique orientations are perceived and discriminated less easily than those close to the horizontal or vertical.
Pulfrich effect See Pulfrich stereophenomenon.
Raman effect In certain substances scattered light may be of a slightly different wavelength from that of the incident light.
Stiles-Crawford effect Variation of the luminosity of a pencil of light stimulating a given receptor with the position of entry of the pencil through the pupil. The maximum luminosity occurs for pencils passing through the centre of the pupil and stimulating the receptor along its axis. This phenomenon is attributed to the particular shape of the cone cells of the retina and occurs only in photopic vision.
Tyndall effect Diffusion of light by the particles present in a liquid or gas. It is because of this effect that heterogeneities (e.g. increased proteins) of the media of the eye can be seen, as occurs in iris and/or ciliary body inflammation. Syn. Tyndall scatter. See aqueous flare.
Aubert's effect See Aubert's phenomenon.
Bezold-Brücke effect See Bezold-Brücke phenomenon.
Broca-Sulzer effect The brightness produced by a flash of a given luminance depends upon its duration. It is maximum for durations around 30-40 ms when the flash luminance is photopic.
Brücke-Bartley effect An increased brightness produced by an intermittent light source (usually around 8-10 Hz) compared to the same light source viewed in steady illumination. Syn. brightness enhancement.
Cheshire cat effect A form of binocular rivalry in which a moving object seen by one eye can cause the entire image, or parts of the image, of a stationary object seen by the other eye to disappear. The effect can be observed by dividing the field of vision with a mirror placed edge-on in front of the nose at a slight angle. One eye looks straight at a stationary object, such as a sleeping cat, while the other eye sees a reflection through the mirror of a white wall or background. If a hand is waved on the mirror side in the region of the field where the cat is seen, the whole cat or part of it may be seen to disappear. See retinal rivalry.
Craik-O'Brien-Cornsweet effect A phenomenon in which the brightness of an area on one side of a transition strip appears greater than the brightness of the area on the other side of the strip, although both areas outside the transition strip have exactly the same luminance. The transition strip consists of two opposing luminance gradients that meet along a linear edge (called Cornsweet edge); on one side the luminance gradually increases to the edge and on the other side the luminance gradually decreases to the edge. The area adjoining the gradient of increasing luminance appears brighter than the area adjoining the gradient of decreasing luminance. One possible explanation is that the edge information predominates and the visual system and brain 'fill-in' the area next to it to construct a higher brightness percept. Note: by covering the transition strip it is easy to confirm that the two areas have the same luminance. Syn. Craik-O'Brien-Cornsweet illusion; Cornsweet illusion.
crowding effect See crowding phenomenon.
differential prismatic effect The difference in prism power induced by a pair of ophthalmic lenses of different power when the eyes look in various directions of gaze (except through the optical centres). Large amounts of differential prismatic effect can hinder fusion and give rise to diplopia. Example: A patient's right eye is corrected by +5 D, the left eye by +2 D. When the eye rotates upward so that the visual axes intersect the lenses 1 cm above the optical centres, the induced prism power becomes 5 Δ base down on the right and 2 Δ base down on the left. The differential prismatic effect is 3 Δ base down in front of the right eye, probably too large for fusion to be maintained. Syn. prismatic imbalance; relative prismatic effect. See anisophoria; Prentice's law.
Gelb effect In a faintly illuminated room a piece of black paper (or a rotating black disc) is illuminated by a high intensity projector. The beam of the projector falls exactly on the area of the black surface. The paper or disc will then appear to be white. A reversal of the perception is accomplished by placing a small piece of white paper near the disc in front of the projected light, at which time the paper or disc reappears in its true colour, i.e. black.
kinetic depth effect An impression of a three-dimensional structure of a moving two-dimensional shadow cast by a three-dimensional object. It is most easily demonstrated by casting a shadow onto a translucent screen.
Mandelbaum effect A tendency for the accommodative response to be altered when interposing a conflicting visual stimulus to the one being viewed. If the eyes are viewing a distant object through a dirty window or a wire fence, the actual accommodative response will tend to be raised. If the eyes are viewing a near object in front of a dirty window or wire fence the actual accommodative response will be less than if there were no conflicting stimulus.
McCollough effect A visual after-effect of colour that is seen when viewing, for a minute at least, two differently oriented and differently coloured gratings, such as a vertical grating with blue and black stripes and a horizontal grating with orange and black stripes. After adapting to these the subject looks at a figure containing a grating of vertical black and white stripes and a grating of black and white horizontal stripes of the same size as the original coloured gratings. The white stripes will then appear to be of the complementary colour, that is, the vertical stripes appear pinkish and the horizontal stripes appear bluish.
moiré effect An illusory shimmering movement produced by moving one pattern superimposed on another pattern very similar to it. The phenomenon occurs because parts of the periodic patterns are in phase in some locations, and out of phase in other locations. Examples: passing by a set of railings; if a transilluminated square wave grating is superimposed on an identical grating but cross each other at an angle of less than 45º, moiré fringes will appear at the intersections. Syn. moiré pattern. See Toposcope.
oblique effect In central vision, contours with oblique orientations are perceived and discriminated less easily than those close to the horizontal or vertical.
Pulfrich effect See Pulfrich stereophenomenon.
Raman effect In certain substances scattered light may be of a slightly different wavelength from that of the incident light.
Stiles-Crawford effect Variation of the luminosity of a pencil of light stimulating a given receptor with the position of entry of the pencil through the pupil. The maximum luminosity occurs for pencils passing through the centre of the pupil and stimulating the receptor along its axis. This phenomenon is attributed to the particular shape of the cone cells of the retina and occurs only in photopic vision.
Tyndall effect Diffusion of light by the particles present in a liquid or gas. It is because of this effect that heterogeneities (e.g. increased proteins) of the media of the eye can be seen, as occurs in iris and/or ciliary body inflammation. Syn. Tyndall scatter. See aqueous flare.
Patient discussion about effect.
Q. Does Viagra have any side effects? My boyfriend started taking Viagra and now he has headaches. Could this be caused by the Viagra?
A. Yes, headaches are a side effect of Viagra. Other common side effects are facial flushing, upset stomach and a temporary bluish vision. If this persists, he should consult his Doctor.
Q. What are the effects of heroin addiction? I just found out that one of my block mates has been using heroin to keep her up all night just so she can study for our exams. But I don't think it's doing her any good. I asked her if she wanted to talk about it, but she refused. I would like to help her get out of heroin addiction while she still can.
A. the most damaging effect of heroin addiction is the addiction itself. The continuous increase in doses would also increase the physical damage it causes and the user's dependence to it, as well.
Her feelings will be numb and she won’t have a problem steeling from her family, selling herself for heroin, very unpleasant things.
So I do hope you get to convince your friend to stop and get treatment as soon as possible –her life depends on it!
Good luck.
Her feelings will be numb and she won’t have a problem steeling from her family, selling herself for heroin, very unpleasant things.
So I do hope you get to convince your friend to stop and get treatment as soon as possible –her life depends on it!
Good luck.
Q. What Are Common Side Effects of Antibiotics? My 5 year old son had an ear infection and was given antibiotics for a few days. What are the known side effects for some of the common antibiotics?
A. Possible side effects of antibiotic medications are varied, depending on the antibiotics used and the microbial organisms we wish to treat. Adverse effects can range from fever and nausea to major allergic reactions. The most common side effects are gastrointestinal- mostly nausea, vomiting, “upset stomach” and diarrhea. Allergic reactions can be mild (rash) and rarely severe (anaphylactic shock). Some antibiotics can cause kidney damage, however this is also very rare.
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