Estimation of noncentrality parameters

We propose some estimators of noncentrality parameters which improve upon usual unbiased estimators under quadratic loss. The distributions we consider are the noncentral chi-square and the noncentral F. However, we give more general results for the family of elliptically contoured distributions and propose a robust dominating estimator.     

非传统安全视角下的云南跨界民族问题

冷战结束后,云南边境地区的安全因素发生了重大变化,安全威胁由防御邻国向我国侵犯等传统安全要素逐渐转向防止各种跨国犯罪和贩毒走私为特征的非传统安全,跨界民族问题成为引发云南边疆地区非传统安全的重要因素之一,给边疆安全带来前所未有的挑战。从云南跨界民族问题与非传统安全关系入手,分析由云南跨界民族所产生的非传统安全问题,提出解决云南跨界民族问题的一些设想,是十分必要的。     

环境问题的社会学探索

环境社会学是二十世纪六、七十年代以来出现的社会学的一门分支学科。社会学在对环境问题的理论探索过程中争论的一个主要焦点是,环境问题是属于自然界的问题,还是属于社会的问题。本文通过对环境社会学理论历程的梳理,试图展现环境问题本身是一个具有复杂性的问题。     

Estimation of Metabolic Rate Constants in PBPK‐Models from Liver Slice Experiments: What Are the Experimental Needs?

A mechanistic model is presented describing the clearance of a compound in a precision-cut liver slice that is incubated in a culture medium. The problem of estimating metabolic rate constants in PBPK models from liver slice experiments is discussed using identifiability analysis. From the identifiability problem analysis, it appears that in addition to the clearance, the compound's free fraction in the slice and the diffusion rate of the exchange of the compound between culture medium and liver slice should be identified. In addition, knowledge of the culture medium volume, the slice volume, the compound's free fraction, and octanol-water-based partition between medium and slice is presupposed. The formal solution for identification is discussed from the perspective of experimental practice. A formally necessary condition for identification is the sampling of parent compound in liver slice or culture medium. However, due to experimental limitations and errors, sampling the parent compound in the slice together with additional sampling of metabolite pooled from the medium and the slice is required for identification in practice. Moreover, it appears that identification results are unreliable when the value of the intrinsic clearance exceeds the value of the diffusion coefficient, a condition to be verified a posteriori.     

论"从日本奇迹到日本问题"

战后创造过经济奇迹的日本 ,在 2 0世纪的最后十年陷入了极其深重的经济危机。究其原因 ,一是独特的法人相互持股制度已从多方面对日本经济的发展形成了桎梏 ;二是银行与企业融合的主办银行制度在进入 80年代后出现了一系列问题 ;三是以终身雇佣制度为核心的企业人力资源管理体制显现出严重的机制性缺陷 ;四是双向式控制的公司治理结构的负作用越来越明显 ;五是政府强干预的经济管理体制的局限性逐渐暴露出来。     

大学精神的失落及其对策研究

文章认为,大学精神的失落是当前我国大学存在的一个突出问题.在剖析其各种表现之后,文章进一步探讨了其产生的原因及危害,并就如何重建大学精神提出了一些建议.     

大学生心理问题及预防初探

当前 ,大学生心理问题不断出现 ,并由此引发了各种疾病 ,直接影响学生正常的学习和生活 ,为了帮助在校学生克服心理障碍 ,顺利完成学业 ,将来健康的走向社会、服务社会 ,作者建议各级教育管理部门及教育工作者 ,平时应重视学生出现的各种心理问题 ,用关心爱护、疏导等方式予以预防 ,只有这样 ,学生心理问题才能很好的得到解决 ,并愉快的投入到学习当中。     

论20世纪50年代中美在台湾问题上的较量

台湾问题历来是影响中美关系的焦点 ,美国为了阻遏共产主义势力的蔓延 ,从军事、外交、经济上采取孤立中国的政策 ,企图“划峡而治之” ,制造“两个中国” ,对此 ,中国政府进行了针锋相对的斗争 ,坚持台湾是中国的领土 ,坚决捍卫“一个中国”原则 ,从而粉碎了美国的阴谋。     

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.     

对偶线性规划问题性质探析

探讨对偶线性规划的原始问题与对偶问题的属性，阐述两者的区别和内在联系，用较简便的方法论证其重要性质，揭示可行解与目标函数、可行解与最优解的关系，指出线性规划问题最优解从约束条件较少的对偶问题寻求为另一较简便之方法。