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-Spermophilus brunneus . , 13 18 ,S. brunneus S. townsendii mollis (2n=38) , , ; ;S. brunneus . S. brunneus , Spermophilus.

Supported by National Science Foundation Grants No. GB32114X and No. GB 29131X, and the Sprague Foundation. We thankD. Pozin for technical assistance.  相似文献   

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This work was supported by a Rackham Grant from the University of Michigan.  相似文献   

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Conclusions The decrease of circulating blood volume, resulting in oligemic hypotension, may evoke in anaesthetized cat the active constrictory coronary vessel responses of 2 types, one occuring immediately after start of the hypotension and the other having a significantly prolonged latency.
, , , , ( 4 ), ( 45 ).
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Summary During the development of anthers inTulipa cv. Apeldoorn the following chalcones were isolated: 2, 3, 4, 4, 6-pentahydroxychalcone as the main component and 2, 4, 4, 6-tetrahydroxy-3-methoxychalcone as well as 2, 4, 4, 6-tetrahydroxychalcone in a very small amount.

Die Untersuchungen wurden mit Mitteln der Deutschen Forschungsgemeinschaft unterstützt.  相似文献   

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Summary Photorefractory male yellow-throated sparrows (Gymnorhis xanthocollis) were subjected to six resonance light cycles, consisting of 6 h basic photophase coupled with scotophases of longer durations (in cycles of 12 (6L6D) h, 24 (6L18D) h, 36 (6L30D) h, 48 (6L42D) h, 60 (6L54D) h and 72 (6L66D) h). Termination of photorefractoriness was evident in cycles of 24, 48 and 72 h, but not in 12, 36 and 60 h. The results are consistent with the external-coincidence model (Bünning hypothesis) and suggest that endogenous circadian rhythmicity is involved in the termination of photorefractoriness.To whom reprint requests should be addressed.This investigation was supported by a UGC grant to PDT and BHU to PMT.  相似文献   

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In a double-blind placebo crossover study of 13 healthy volunteers, the pineal hormone melatonin (10 mg) was given at 4 pm, and the electroretinogram measured under conditions of dark and light adaptation. A significant diminution of b-wave amplitude was found under both photopic (=5.4 V, p<0.05) and scotopic conditions (=7.4 V, p<0.01). These data indicate that melatonin may transduce the dark signal at the level of the retina as well as the pineal. Acute administration of melatonin decreases sensitivity to light.  相似文献   

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