ray
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ray
[ra]a line emanating from a center, as a more or less distinct portion of radiant energy (light or heat), proceeding in a specific direction.
α-r's high-speed helium nuclei ejected from radioactive substances; they have less penetrating power than beta rays. See also alpha particles.
actinic r's light rays that produce chemical action, especially those beyond the violet end of the spectrum.
alpha r's α-rays.
β-r's (beta r's) electrons ejected from radioactive substances with velocities as high as 98 per cent of the velocity of light; they have more penetrating power than alpha rays but less than gamma rays. See also beta particles.
cosmic r's very penetrating radiations that apparently move through interplanetary space in every direction.
digital ray a digit of the hand or foot and corresponding metacarpal or metatarsal bone, regarded as a continuous unit.
γ-r's (gamma r's) a type of electromagnetic radiation emitted by an atomic nucleus during a nuclear reaction; see also gamma rays.
grenz r's very soft electromagnetic radiation of wavelengths of about 2 angstroms.
infrared r's radiations just beyond the red end of the visible spectrum, having wavelengths of 0.75–1000 μm; see also infrared.
medullary ray a cortical extension of a bundle of tubules from a renal pyramid.
roentgen r's x-rays.
ultraviolet r's radiant energy beyond the violet end of the visible spectrum, of wavelengths 0.39 to 0.18 μm; see also ultraviolet rays.
x-r's see x-rays.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
ray
(rā),1. A beam of light, heat, or other form of radiation. The rays from radium and other radioactive substances are produced by a spontaneous disintegration of the atom; they are electrically charged particles or electromagnetic waves of extremely short wavelength.
2. A part or branch that extends radially from a structure.
[L. radius]
Farlex Partner Medical Dictionary © Farlex 2012
RAB35
A gene on chromosome 12q24.31 that encodes a member of the Rab subfamily of Ras-related small GTPases, which is involved in endocytosis and is the essential rate-limiting regulator of a fast recycling pathway back to the plasma membrane. During cytokinesis, RAB35 is needed to ensure intercellular bridge stability and abscission.Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
ray
(rā)1. A beam of light, heat, or other form of radiation. The rays from radium and other radioactive substances are produced by a spontaneous disintegration of the atom; they are electrically charged particles or electromagnetic waves of extremely short wavelength.
2. A part or branch that extends radially from a structure.
3. One of the grooves of the embryonic hand and foot indicating where the digital rays (e.g., hand rays) will develop.
[L. radius]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
ray
- see MEDULLARY RAY.
- a cartilagenous fish of the genus Raia, closely allied to the skate.
- a bony rod supporting the fin of a fish.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
ray
In geometrical optics, a straight line representing the direction of propagation of light.
axial ray A ray that is coincident with the axis of an optical system.
chief ray A ray joining an object point to the centre of the entrance pupil of an optical system (Fig. R2). See pencil of light.
emergent ray A ray of light in image space either after reflection (reflected ray) or after refraction (refracted ray).
extraordinary ray See birefringence.
incident ray A ray of light in object space that strikes a reflecting or refracting surface.
marginal ray A ray joining the axial point of an object to the edge or margin of an aperture or pupil (Fig. R2).
ordinary ray See birefringence.
paraxial ray A light ray that forms an angle of incidence so small that its value in radians is almost equal to its sine or its tangent. (i.e. sin θ = θ or tan θ = θ. These are approximate expressions referred to as the paraxial approximation (or the gaussian approximation). See paraxial optics; paraxial region; gaussian theory.
principal ray A ray joining the extreme off-axis object point to the centre of the entrance pupil or aperture (Fig. R2).
ray tracing Technique used in optical computation consisting of tracing the paths of light rays through an optical system by graphical methods or by using formulae. Nowadays, computer methods are used. See sign convention.
axial ray A ray that is coincident with the axis of an optical system.
chief ray A ray joining an object point to the centre of the entrance pupil of an optical system (Fig. R2). See pencil of light.
emergent ray A ray of light in image space either after reflection (reflected ray) or after refraction (refracted ray).
extraordinary ray See birefringence.
incident ray A ray of light in object space that strikes a reflecting or refracting surface.
marginal ray A ray joining the axial point of an object to the edge or margin of an aperture or pupil (Fig. R2).
ordinary ray See birefringence.
paraxial ray A light ray that forms an angle of incidence so small that its value in radians is almost equal to its sine or its tangent. (i.e. sin θ = θ or tan θ = θ. These are approximate expressions referred to as the paraxial approximation (or the gaussian approximation). See paraxial optics; paraxial region; gaussian theory.
principal ray A ray joining the extreme off-axis object point to the centre of the entrance pupil or aperture (Fig. R2).
ray tracing Technique used in optical computation consisting of tracing the paths of light rays through an optical system by graphical methods or by using formulae. Nowadays, computer methods are used. See sign convention.
)
Fig. R2 Rays of light incident to the eye (E, centre of the entrance pupil of the eye)
| Table R1 Differences between the sine and the tangent values of various angles (in degrees and radians). The error is calculated between the sine value and the value in radians and between the value in radians and the tangent value | ||||||||||
| angle (deg) | angle (rad) | sine value | tangent value | error (%) sine error | error (%) tangent error | |||||
| 0.5 | 0.008 727 | 0.008 727 | 0.008 727 | 0.00 | 0.00 | |||||
| 1 | 0.017 453 | 0.017 452 | 0.017 455 | 0.01 | 0.01 | |||||
| 2 | 0.034 907 | 0.034 899 | 0.034 921 | 0.02 | 0.04 | |||||
| 3 | 0.052 360 | 0.052 336 | 0.052 408 | 0.05 | 0.09 | |||||
| 4 | 0.069 813 | 0.069 756 | 0.069 927 | 0.08 | 0.16 | |||||
| 5 | 0.087 266 | 0.087 156 | 0.087 489 | 0.13 | 0.25 | |||||
| 6 | 0.104 720 | 0.104 528 | 0.105 104 | 0.18 | 0.37 | |||||
| 7 | 0.122 173 | 0.121 869 | 0.122 785 | 0.25 | 0.50 | |||||
| 8 | 0.139 626 | 0.139 173 | 0.140 541 | 0.33 | 0.65 | |||||
| 10 | 0.174 533 | 0.173 648 | 0.176 327 | 0.51 | 1.03 | |||||
| 15 | 0.261 799 | 0.258 819 | 0.267 949 | 1.15 | 2.35 | |||||
| 520 | 0.349 066 | 0.342 020 | 0.363 970 | 2.06 | 4.27 | |||||
| 30 | 0.523 599 | 0.500 000 | 0.577 350 | 4.72 | 10.27 | |||||
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
ray
(rā)1. Beam of light, heat, or other form of radiation.
2. A part or branch that extends radially from a structure.
[L. radius]
Medical Dictionary for the Dental Professions © Farlex 2012
Patient discussion about ray
Q. Is an X- Ray dangerous to my fetus? I fell down while I am pregnant and was sent to the ER. I was given an x- ray there, is the radiation dangerous to my fetus?
A. As far as I know one x-ray cannot harm your fetus since there is not enough radiation there to harm it. If you are worried consult a Doctor.
Q. What does radiation do for cancer patients? We found out today that my grandmother has cancer and my mother said that the oncologist is planning on using radiation to ease her pain. My question is, what does radiation do? I know, eases pain, but how?
A. hello;radiation therapy/an anticancer drugs are used to suppress or arrest the rate of cell division in any tumor cells, the rad also kills good cells also.
Q. Is it proven that cellular radiation can damage health?
A. it was proven that people that talk a lot with cellular phones tend to develop problems in their salivary gland (the Parotid gland, right under the ear)that is on the side they speak the most.
http://www.newsinferno.com/archives/2163
could be that in 15 years from now the amount of brain cancer will increase and they will know for sure it's from cellular phones. , why take a chance- use as less as possible, use an earphone and don't give a cellular phone to your children until they are 17.
you can never know what will they find next...
More discussions about rayhttp://www.newsinferno.com/archives/2163
could be that in 15 years from now the amount of brain cancer will increase and they will know for sure it's from cellular phones. , why take a chance- use as less as possible, use an earphone and don't give a cellular phone to your children until they are 17.
you can never know what will they find next...
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