从交流和传播的视角解读越文化

本组讨论以越文化研究为例,探索地域文化研究的方法与视角。朱文斌一文检讨了当前越文化研究范式的局限,提出了范式转换的问题;陈越、梁涌两文分别从空间与时间的存在与发展上对越文化作了动态描述。其中,陈文从文化模式的角度,把越文化概括为“剑—书”文化;梁文则从交流与传播的角度,揭示了越文化的形成与发展。     

论校园时尚语境下的大学生思想政治教育

大学校园时尚的产生有其必然性,它对学生的思想政治教育既有积极意义,又会产生消极影响.基于此,必须积极应对大学校园时尚的冲击,在校园时尚语境下把大学生思想政治教育提升到新的局面.     

饥饿和再投喂对草鱼鱼种糖代谢的影响

分析了草鱼鱼种在饥饿和再投喂下血糖浓度和红肌、白肌和肝脏糖原含量的变化 .结果显示 ,饥饿状态下 ,草鱼鱼种肝糖原含量的下降快于血糖浓度的下降 ,饥饿 3d后肝糖原含量显著低于对照组 ,饥饿 15d血糖浓度显著降低 ,提示草鱼鱼种在饥饿状态下通过分解肝糖原维持血糖浓度 ;再投喂后 ,血糖浓度、肝糖原含量恢复正常 ,但均低于对照组 .饥饿使红肌糖原含量降低 ,并先于白肌糖原含量下降 ,饥饿 1d红肌糖原含量显著低于对照组 ,饥饿 7d白肌糖原含量显著下降 .再投喂 2 1d红肌糖原含量恢复正常 ,再投喂 7d白肌糖原含量恢复正常 .说明饥饿状态下糖原含量变化越快 ,再投喂后恢复就越慢     

结合农业现状改革大学动物学实验内容

分析了大学动物学实验内容的现状和现代农业生产发展的趋势。对大学动物学实验内容的改革作了初步探讨。通过两者的有机结合 ,提高动物学实验教学的科学性、合理性和实用性 ,促进现代农业技术的发展     

建立题库:教考分离的有效手段

教考分离已成为目前教学改革的一个发展方向。建立题库正是改革传统考试制度 ,实现教考分离的一种有效手段。     

转子动不平衡载荷的在线识别

本文提出用复模态影响系数来解决转了大衡的在线以别和诊断问题，讨论了影响系数矩阵的力学意义．试验中可不加试重求出影响系数，并编制了相应的计算程序．     

大学生英语交际能力的培养

培养学生用英语进行交际的能力是大学英语教学的重点。要提高学生的交际能力 ,就要注意学生听说能力的培养 ,这需要我们教师从课堂教学入手。     

对三农问题的哲学思考

农业在国民经济中的重要性众所周知。本文通过对最能体现农业重要性的例子、四大文明的诞生和英国的工业革命等人类文明史的阐述,用哲学的思维对当代中国的农业、农村、农民做了初步的探讨。     

Bootstrap Estimation of Benchmark Doses and Confidence Limits with Clustered Quantal Data

The benchmark dose (BMD) is an exposure level that would induce a small risk increase (BMR level) above the background. The BMD approach to deriving a reference dose for risk assessment of noncancer effects is advantageous in that the estimate of BMD is not restricted to experimental doses and utilizes most available dose-response information. To quantify statistical uncertainty of a BMD estimate, we often calculate and report its lower confidence limit (i.e., BMDL), and may even consider it as a more conservative alternative to BMD itself. Computation of BMDL may involve normal confidence limits to BMD in conjunction with the delta method. Therefore, factors, such as small sample size and nonlinearity in model parameters, can affect the performance of the delta method BMDL, and alternative methods are useful. In this article, we propose a bootstrap method to estimate BMDL utilizing a scheme that consists of a resampling of residuals after model fitting and a one-step formula for parameter estimation. We illustrate the method with clustered binary data from developmental toxicity experiments. Our analysis shows that with moderately elevated dose-response data, the distribution of BMD estimator tends to be left-skewed and bootstrap BMDL s are smaller than the delta method BMDL s on average, hence quantifying risk more conservatively. Statistically, the bootstrap BMDL quantifies the uncertainty of the true BMD more honestly than the delta method BMDL as its coverage probability is closer to the nominal level than that of delta method BMDL. We find that BMD and BMDL estimates are generally insensitive to model choices provided that the models fit the data comparably well near the region of BMD. Our analysis also suggests that, in the presence of a significant and moderately strong dose-response relationship, the developmental toxicity experiments under the standard protocol support dose-response assessment at 5% BMR for BMD and 95% confidence level for BMDL.