rotation

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rotation

1. Spinning motion of a celestial body or a group of gravitationally bound bodies, such as a galaxy, about an axis, as distinct from orbital revolution. Almost all celestial bodies show some degree of rotation. Young stars arrive on the main sequence with a high rotation rate; this results from the conservation of angular momentum during their collapse from a cloud of interstellar gas. As a star ages, structural changes in its interior and interactions with its surroundings produce changes in its speed of rotation. The hottest (O and B) stars have very great rotation rates of about 200–250 km s–1. Sunlike stars spin more slowly as they age, although some are able to retain their rapid rotation. The faster the rate of rotation the broader and shallower the star's spectral lines and the stronger the magnetic field (see corona). See also differential rotation; direct motion; synchronous rotation.
2. One complete turn of a celestial body about its axis. The Earth takes one sidereal day to make one rotation. Ideally the rotation period of other bodies is measured as the time interval between successive passages of a meridian line on the surface across the center of the disk, as seen from Earth. The solid surface may however be unobservable and indirect measurements, as by radar, are then employed. The rotation period of a gaseous body, such as the Sun or the planet Jupiter, varies with latitude, being greatest at the equator (see differential rotation).
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

rotation

[rō′tā·shən]
(computer science)
An operation performed on data in a register of the central processing unit, in which all the bits in the register are shifted one position to the right or left, and the endmost bit, which is shifted out of the register, is carried around to the position at the opposite end of the register.
(mathematics)
(mechanics)
Also known as rotational motion.
Motion of a rigid body in which either one point is fixed, or all the points on a straight line are fixed.
Angular displacement of a rigid body.
The motion of a particle about a fixed point.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
At Beresford, the experiment was started in 1991 (24 years) to study the effects of tillage management and crop rotations on crop production and soil properties.
With regard to crop rotation, amaranth planted after yard long bean, produced the maximum yield (889.81 g/m2) of amaranth, when grown in VC+YLB rotation treatment and the lowest yield (222.18 g/m2) was observed in FP+YLB treatment.
Tillage and crop rotations and their interactions had significant (P < 0.05) effect on soil dehydrogenase enzyme activity of top soil layer (fig.
The correlation between silt/clay ratios and Ap thickness values showed that under all crop rotations the active erosion segments have lighter soil textures than the other segments (r = 0.93, p [less than or equal to] 0.05, n = 27).
Stationary experiment on studying the effect of application of soil tillage methods in arable crop rotation on the yield of agricultural crops is a time-consuming test, registered in the VNIIA RF geo-system certificates register of long-term experiments under the title "Theoretical and technological bases of biogeochemical matter fluxes in agricultural landscapes." The experimental scheme is 4 x 4 x 8 and contains 128 plots (4 options of methods of tillage; 4 options of doses of fertilizers; 8 options crop).
Similarly inclusion of allelopathic crops in crop rotation and intercropping showed encouraging results regarding weed control.
Fortunately, interpretations of the remotely sensed crop data also indicated that farmers are shifting to longer crop rotations that intersperse small grains with potato.
distribution of P and the availability of this P to crops under different tillage practices and crop rotations, particularly in relation to the relatively dry seasonal conditions that characterise cropping in south-eastern Australia, may have significant practical implications for fertiliser management (White 1990; Wang et al.
It is possible to achieve biodiversity on a farm by using cropping systems that include crop rotations, polycultures, multiple cropping, and agroforestry.
Crop rotation has become a proven way to boost crop yields on the Ranft farm.
PGR was calculated for three crop rotations: wheat phase (1999-2000), sunflower phase (2000-2001), and wheat phase (2001-2002).