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).

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.
References in periodicals archive ?
After weighing the costs and benefits of different management systems, Larkin concluded that using a combination of Brassica and sudangrass green manures, fall cover crops, and crop rotations can reduce soilborne diseases by up to 58 percent--and adding compost to the mix increases tuber yields up to 42 percent.
We examine the potential contributions of optimized soil fumigation methods, crop rotation and rootstock selection to the integrated management of PRD and reduced fumigant use.
In this study, perennial pasture had the highest total C and N values and the greatest CMI, suggesting greater capacity for C sequestration compared with the annual pasture and crop rotations.
Crop rotation and cover cropping; soil resiliency and health on the organic farm, rev.
Improved varieties, genetic breakthroughs, strip-till, no-till, cover crops, and multiple crop rotations combined with equipment efficiencies and innovations will provide many of the answers.
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.
Crop producers must become convinced that permanently altering their crop rotations makes agronomic and economic sense.
In that area, one farm has relied on crop rotations and native soil fertility for plant nutrients ever since it was first plowed in 1909.
Rare Look at Global Warming Effects on Crop Rotations
Loss of wildlife diversity on farm land is also not a problem specific to GM but of agriculture in general; the losses of habitat, use of fertilisers and pesticides, and changes in crop rotations have all reduced the numbers of plants, insects and birds in Britain (15).
In this part of the country, crop rotations tend to be tight and include many crops such as oilseed rape and potatoes that are susceptible to this disease.
Crop rotations in combination with either reduced or minimum tillage have become a feature of cotton-based (Gossypium hirsutum L.