Physiologically Based Liver Modeling and Risk Assessment

Because of the inherent complexity of biological systems, there is often a choice between a number of apparently equally applicable physiologically based models to describe uptake and metabolism processes in toxicology or risk assessment. These models may fit the particular data sets of interest equally well, but may give quite different parameter estimates or predictions under different (extrapolated) conditions. Such competing models can be discriminated by a number of methods, including potential refutation by means of strategic experiments, and their ability to suitably incorporate all relevant physiological processes. For illustration, three currently used models for steady-state hepatic elimination--the venous equilibration model, the parallel tube model, and the distributed sinusoidal perfusion model--are reviewed and compared with particular reference to their application in the area of risk assessment. The ability of each of the models to describe and incorporate such physiological processes as protein binding, precursor-metabolite relations and hepatic zones of elimination, capillary recruitment, capillary heterogeneity, and intrahepatic shunting is discussed. Differences between the models in hepatic parameter estimation, extrapolation to different conditions, and interspecies scaling are discussed, and criteria for choosing one model over the others are presented. In this case, the distributed model provides the most general framework for describing physiological processes taking place in the liver, and has so far not been experimentally refuted, as have the other two models. These simpler models may, however, provide useful bounds on parameter estimates and on extrapolations and risk assessments.     

论企业文化传播的主受体二重性

文章运用传播学理论和企业文化理论 ,论述了企业文化传播的主受体二重性的问题。通过对企业文化传播中的主受体关系进行分析 ,提出了企业文化传播的内传播二重性和外传播二重性 ,及其主受体互换的观点。     

编辑传播学的研究对象与性质

编辑传播学是以编辑主体的传播劳动作为自己研究对象的理论体系。其研究视角有宏观与微观两种。涉及编辑传播的性质、编辑传播的功能、编辑传播的主体、编辑传播的内容、编辑传播的流程、编辑传播的效果、编辑传播与文化的建构等。编辑传播学是综合传播学和编辑学而建立的交叉性的边缘学科,属于普通编辑学的研究范畴。     

大学英语交际法浅议

交际是最快 ,最直接地表达思想的途径。只有在交际的过程中 ,学生才能真正掌握语言的技能     

网络文学与文学本质

网络文学的出现再次激起我们对“文学本质”的追问。网络文学文本的生存形式从一个全新的层面给我们提供了一个较全面关照和认识文学 (及其传统 )的视角 ,只有以开放的心态和宽容的态度面对文学现实本身 ,我们才能更清楚地看清文学自身的逻辑 ,从而更接近和理解文学的本质。     

跨文化交际中的时空观念差异

不同文化背景的人,由于受不同文化传统的影响,其思维方式不同,在人际交往中的时间观念(如时间顺序排列、时间取向、遵守时间的态度)和空间观念(如对体距的认识、对个人领地的态度等)也存在差异。这些差异往往容易被人们忽视,从而影响交际的正常进行,甚至导致交际的失败。因此,在交往中我们应该正确对待文化差异,自觉排除文化差异的干扰。     

Bayesian analysis of directed graphs data with applications to social networks

Summary.  A fully Bayesian analysis of directed graphs, with particular emphasis on applica- tions in social networks, is explored. The model is capable of incorporating the effects of covariates, within and between block ties and multiple responses. Inference is straightforward by using software that is based on Markov chain Monte Carlo methods. Examples are provided which highlight the variety of data sets that can be entertained and the ease with which they can be analysed.     

科技传播研究:“普及范式”和“创新范式”

国内科技传播研究在近几年渐见繁荣之势。为了促进科技传播研究在国内更好地发展，文章讨论了已得到一定发展的“普及范式”和正在发展中的“创新范式”，认为面向未来知识经济的发展，需要推进“创新范式”的科技传播研究。     

New imperfect rankings models for ranked set sampling

Ranked set sampling is a sampling approach that leads to improved statistical inference in situations where the units to be sampled can be ranked relative to each other prior to formal measurement. This ranking may be done either by subjective judgment or according to an auxiliary variable, and it need not be completely accurate. In fact, results in the literature have shown that no matter how poor the quality of the ranking, procedures based on ranked set sampling tend to be at least as efficient as procedures based on simple random sampling. However, efforts to quantify the gains in efficiency for ranked set sampling procedures have been hampered by a shortage of available models for imperfect rankings. In this paper, we introduce a new class of models for imperfect rankings, and we provide a rigorous proof that essentially any reasonable model for imperfect rankings is a limit of models in this class. We then describe a specific, easily applied method for selecting an appropriate imperfect rankings model from the class.     

D-efficient window experimental designs

In the paper we present a new method of calculating sampling intervals, so-called windows, allowing an experimenter some flexibility in timing the sample collection, while a minimum required design efficiency for parameter estimation is assured. The method is based on the Equivalence Theorem for D-optimality what makes the length of each window related to the parameter sensitivities. An example of calculating the windows in a pharmacokinetic study is presented. Some other methods of calculating efficient sampling windows are briefly discussed.