Circadian periodicity in termination of photorefractoriness in the yellow-throated sparrow

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.     

华南中小流域设计暴雨洪水同频率检验与重现水平推算

暴雨洪水同频率假定是否成立和暴雨洪水遭遇概率分布是中小流域设计洪水计算的依据,为检验其合理性,采用鉴江上游曹江流域典型强降水流域1967—2013年逐时暴雨洪水观测资料,分析了华南中小流域最大面雨量R和对应场次最大洪峰流量Q的边缘分布和联合分布的遭遇概率,并推算其设计重现水平。研究结果表明：暴雨和洪水同频遭遇概率较小;对于特定设计频率,洪峰流量与流域面雨量的遭遇概率随流域面雨量增大而增大;流域面雨量和洪峰流量的遭遇条件概率显示存在着多种防洪风险管理选择;相对于“或”联合重现期和“且”重现期,二次重现期更准确地反映R-Q组合的风险率。     

比较两组样本均值的随机加权法

利用随机加权法给出了两组相互独立的样本均值比较的假设检验,这种检验并不要求被检样本分布一定是正态的,同时证明在适当条件下所用的估计比通常的正态逼近具有更高的精度。     

一种新的基于假设的自然推理系统

本文在介绍自动定理证明的历史和分析自然推理研究的现有成果的基础上,提出了用以实现启发式自然推理系统HNDS的确定性推理算法。并设计了用作推理基本手段的假设机制。本系统采用知识库系统的软件结构,面向标准形式的命题逻辑和一阶谓词逻辑,对系统定理能给出清晰的类人证文过程。HNDS系统基于的推理算法理论上是合理的和完备的,这主要因为系统结合了自然推理与消解原理,并首创了量词逐层Skolem化的策略。     

一种预测蛋白质二级结构的简便方法

以“广义摆动假说”为理论基础,从基因密码子的第二位碱基入手,把氨基酸——“词”简并成核苷酸——“语言”,可直接预测蛋白质的二级结构,从对一些蛋白质的预测结果可见,准确度与Chou-Fasman法相近。     

Cubature Kalman probability hypothesis density filter based on multi-sensor consistency fusion①

The GM-PHD framework as recursion realization of PHD filter is extensively applied to multi-target tracking system .A new idea of improving the estimation precision of time-varying multi-target in non-linear system is proposed due to the advantage of computation efficiency in this paper .First, a novel cubature Kalman probability hypothesis density filter is designed for single sensor measure -ment system under the Gaussian mixture framework .Second , the consistency fusion strategy for multi-sensor measurement is proposed through constructing consistency matrix .Furthermore, to take the advantage of consistency fusion strategy , fused measurement is introduced in the update step of cubature Kalman probability hypothesis density filter to replace the single-sensor measurement .Then a cubature Kalman probability hypothesis density filter based on multi-sensor consistency fusion is proposed .Capabilily of the proposed algorithm is illustrated through simulation scenario of multi-sen-sor multi-target tracking .     

应用正态总体假设检验评价教师教学水平

分析学生学习成绩的结构 ,以学生的相对成绩为样本 ,应用正态总体假设检验 ,提出了一种评价教师教学水平的方法     

中外合作教学模式运用在英语口语教学中的调查报告

以英语口语教学实践为基础，对中外合作教模式的运用进行问卷调查，就中外合作教学模式的适应性，尤其是合作教学的效果进行论证，以证明这种教学模式是切实可行的。从得到的数据可以看出，这一模式的教学效果是好的。     

自然数的cube—free因子的个数

在黎曼假设下研究了自然数的ｃｕｂｅ－ｆｒｅｅ因子数的均值估计，得到了目前最好的上界估计。