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61.
A simple method for isolating large quantities of human metaphase chromosomes has been developed. Fractionation of chromosomes from peripheral lymphocytes on a large scale is accomplished by velocity sedimentation in an A-XII zonal rotor. 相似文献
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Mating behavior in sexually naive and sexually experienced male golden hamsters was totally eliminated by removing their olfactory bulbs. In contrast, the mating behavior in blinded, unilaterally bulbectomized, and sham-operated controls was essentially normal. Testosterone injections restored normal sexual behavior in castrated controls but had no effect on the bilaterally bulbectomized animals. 相似文献
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Olfactory receptor responses (electroantennograms) were recorded from antennae of danaid butterflies. Antennae of male and female queen butterflies (Danaus gilippus berenice) respond equally strongly to the hairpencil of queen males, to its crude extract, and to one of its two identified secretory components (the ketone). Responses to the second component (the diol) are weak. Hairpencils of a related species, Lycorea ceres, which also contain the ketone, are equally effective in eliciting electroantennograms from both sexes of the queen. Antennae of another related species, the monarch (Danaus plexippus), respond to the same stimuli as does the queen. Monarch hairpencils, which lack the ketone, do not elicit electroantennograms in monarch or queen antennae. 相似文献
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A visual analog to binaural unmasking was explored. The observer's task was to detect, under stereoscopic viewing conditions, an apertured sinusoidal grating added to a square patch of visual noise. In the experimental condition, the square patch of noise was presented within a frame such that the right-eye noise was a shifted version of the left-eye noise. Because of the disparity in the noise images, subjects perceived, under stereoscopic viewing conditions, that the noise patch was located behind the frame. When sinusoidal signals were added to this noise patch, the signals were clearly more detectable when the signal disparity was zero than when the signal disparity equaled that of the noise patch, demonstrating the existence of visual unmasking. Hence, under appropriate circumstances, binocular processing, in addition to providing information about depth, can also enhance the detectability of visual patterns. 相似文献
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Retrograde amnesia was produced in rats by electroconvulsive shock. Memory recovered if the animals were given repeated test trials. Memory did not recover if steps were taken to reduce the conditioning properties of the test trials; the manipulations included eliminating the response, altering the apparatus cues, or extinguishing conditioned "fear" by confining animals to the apparatus during the first test trial. 相似文献