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V Switzer RC rdBogo G A Mickley 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(10):443-451
Application of the degeneration sensitive, cupric-silver staining method to brain sections of male Sprague-Dawley rats irradiated 4 days before sacrifice with 155 Mev protons, 2-8 Gy at 1 Gy/min (N=6) or 22-l0lGy at 20 Gy/min (N=16) or with 18.6 Mev electrons, 32-67 Gy at 20 Gy/min (N=20), doses which elicit behavioral changes (accelerod or conditioned taste aversion), resulted in a display of degeneration of astrocyte-like cell profiles which were not uniformly distributed. Plots of 'degeneration scores' (counts of profiles in 29 areas) vs. dose for the proton and electron irradiations displayed a linear dose response for protons in the range of 2-8 Gy. In the 20-100 Gy range, for both electrons and protons the points were distributed in a broad band suggesting a saturation curve. The dose range in which these astrocyte-like profiles becomes maximal corresponds well with the dose range for the X-ray eradication of a subtype of astrocytes, 'beta astrocytes'. 相似文献
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R.B. Dahlburg L. Rudakov C. Crabtree G. Ganguli 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
The evolution of a magnetized conducting medium suspended in magnetic and gravitational fields is examined. In this paper some effects of the influence of velocity fields on the linear stability properties of such layers are investigated. A fully compressible, three-dimensional analysis of the layer is described. The relevant equations are derived and then solved by the MagnetoHydroDynamic SPEctral Compressible Linear Stability (MHDSPECLS) algorithm, a Chebyshev collocation code. The code allows for the computation of magnetic and thermal effects. A complete stabilization of the system is found above a critical velocity of approximately 2500 m/s. 相似文献
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A recent series of papers have provided a model for a staggered-PRF radar which can be used to estimate both the depth of the first null (which is dependent upon the ratio of some function fM(?) of the set of M sampling deviations {?m} to the average sampling interval) and the clutter attenuation (as a function of the product of fM(?) and clutter standard deviation ?c). Some inconsistencies in the aforementioned papers are discussed and it is shown that realistic filters and typical stagger-ratio sets produce results which differ significantly from the idealized-filter predictions. Furthermore, even after filtering the residual clutter power at dc is shown to be more significant than the power in all the displaced clutter spectra postulated by the aforementioned model. 相似文献
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