منابع مشابه
Opinion Opinion Opinion
A common notion of vision, consistent with this excerpt from the first paragraph of David Marr’s seminal book [1], is gained by considering the predicament of a person with a searchlight placed in a pitch-dark room full of unfamiliar furniture. One would hope that, by swinging the beam around, the observer will be able to recognize the objects present in the room (a cat here, an aquarium there,...
متن کاملOscillating wildly
ome cells can induce the production of their own protective blanket. The signal comes from active neurons in the central nervous system (CNS), and triggers the differentiation of oligodendrocyte precursor cells (OPCs)—thus yielding the cells that cover the neurons with a protective sheath of myelin. Now, Beth Stevens, Douglas Fields, and colleagues (National Institutes of Health, Bethesda, MD) ...
متن کاملOscillating Diaphragms
The manufacture of miniature Stirling cycle cryocoolers, using standard micro-machining techniques and materials has been pursued by the authors [1]. A MEMS based cryocooler would allow integration of a cryogenic cooling system directly into a cryoelectronic device. Resonant bossed diaphragms were proposed as the means to sweep the working gas in the Stirling cooler, replacing the pistons and d...
متن کاملRapidly oscillating Ap stars versus non-oscillating Ap stars
The positions in the HR diagram and the kinematic characteristics of rapidly oscillating and non-oscillating chemically peculiar stars are obtained using new Hipparcos proper motions and parallaxes, and our own radial velocity measurements. We find that rapidly oscillating stars, as a group, are (−0.47±0.34) mag above the zero-age main sequence (ZAMS), while the non-oscillating stars are (−1.20...
متن کاملExtinction of oscillating populations.
Established populations often exhibit oscillations in their sizes that, in the deterministic theory, correspond to a limit cycle in the space of population sizes. If a population is isolated, the intrinsic stochasticity of elemental processes can ultimately bring it to extinction. Here we study extinction of oscillating populations in a stochastic version of the Rosenzweig-MacArthur predator-pr...
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ژورنال
عنوان ژورنال: Nature
سال: 2000
ISSN: 0028-0836,1476-4687
DOI: 10.1038/35050198