Speeding into coordinated movement.Whether it's a precision marching band Noun 1. marching band - a band that marches (as in a parade) and plays music at the same time band - instrumentalists not including string players striding through a complex routine or a school of fish executing a sharp turn, coordinated motion is an impressive sight. Even bacteria in large, growing colonies can exhibit cooperative movement cooperative movement, series of organized activities that began in the 19th cent. in Great Britain and later spread to most countries of the world, whereby people organize themselves around a common goal, usually economic. to survive under unfavorable conditions. Now, a group of physicists has developed a simple computer model that illustrates how rudimentary rules of behavior applied to self-propelled particles moving independently can lead to synchronized syn·chro·nize v. syn·chro·nized, syn·chro·niz·ing, syn·chro·niz·es v.intr. 1. To occur at the same time; be simultaneous. 2. To operate in unison. v.tr. 1. activity. Tamas Vicsek of Eotvos University in Budapest and his coworkers describe their model in the Aug. 7 Physical Review Letters Physical Review Letters is one of the most prestigious journals in physics.[1] Since 1958, it has been published by the American Physical Society as an outgrowth of The Physical Review. . In their model, a given area is sprinkled with a certain number of particles. Each particle moves at the same speed, but in a random direction. Starting with this configuration, the computer calculates particle velocities at subsequent times according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. a simple rule: With each time step, every particle assumes the average direction of motion of the particles in its immediate neighborhood, modified by a small, random perturbation perturbation (pŭr'tərbā`shən), in astronomy and physics, small force or other influence that modifies the otherwise simple motion of some object. The term is also used for the effect produced by the perturbation, e.g. . Computer simulations reveal that the type of movement observed depends on the number of particles packed into a given area and on the level of random perturbation, or noise (see illustrations). Remarkably, at high densities and low noise, all of the particles end up moving in the same spontaneously selected direction. "The proposed model is interesting because of possible applications in a wide range of biological systems involving clustering and migration," the researchers say. For example, with some modifications, it is capable of reproducing the collective rotation and flocking of bacteria (SN: 3/4/95, p. 136). |
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