企业的合约经济理论探索和统计检验

对企业本质的认识是微观经济学中的一个重要问题,其对中国的国企改革有着重要意义。本文中,我们对企业的合约本质进行了经济理论探索和统计检验,并突出关注企业的激励合约问题。     

Testing symmetry under a skew Laplace model

We develop tests of hypothesis about symmetry based on samples from possibly asymmetric Laplace distributions and present exact and limiting distribution of the test statistics. We postulate that the test statistic derived under the Laplace model is a rational choice as a measure of skewness and can be used in testing symmetry for other, quite general classes of skew distributions. Our results are applied to foreign exchange rates for 15 currencies.     

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.     

人民币汇率波动与贸易收支的协整分析

本文研究的是1985-2004年我国的进出口价格的需求弹性。首先给出了进出口价格需求弹性理论说明,接着通过平稳性检验、协整检验、建立误差修正模型等方法,分别对进口相对价格需求弹性和出口相对价格需求弹性进行实证检验。分析表明在我国ML条件成立,人民币汇率波动对我国进出口有显著的影响。     

On Rao score and PearsonX 2 statistics in generalized linear models

The identity of the Rao score and PearsonX ² statistics is well known in the areas where the latter was first introduced: goodness-of-fit in contingency tables and binary responses. We show in this paper that the same identity holds when the two statistics are used for testing goodness-of-fit of Generalized Linear Models. We also highlight the connections that exist between the two statistics when they are used for the comparison of nested models. Finally, we discuss some merits of these unifying results. Work financially supported by cofin. MIUR grants 2000 and 2002.     

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.     

THEMA剑杆织机的实验与分析

运用机械动态参数测试仪 ,通过对THEMA剑杆织机的开口、引纬机构进行动态测试 ,利用计算机处理有关测试数据 ,分析和讨论了该机的主要技术参数     

关于外语专业题库建设范式的探讨

本文通过对当前国内外语教育形式的综览 ,指出了外语专业的题库建设已成为当务之急 ,并通过对各种考试形式的分析 ,提出了外语题库建设的具体理论模式———以项目反应理论为基础的计算机自适应测试。文章就有关方面的实施提出了自己的看法。     

递推法求一元n次实系数多项式函数的完全等价n次Bezier参数曲线

用递推方法论证了至少存在一条n次Bezier参数曲线与一元n次实数多项式函数完全等价。同时给出了将一元n次实纱多项式转换为完全等价的n次Bezier参数曲线的方法。     

当前我国公务员考录管理制度弊端分析

当前我国公务员考试录用管理制度存在缺乏法律保障,报名资格随意规定,考试科目和内容设置不科学,考试录用环节不合理,考试监督体系不完善等蔽端。这些问题亟待借鉴发达国家的公务员考试录用经验,在现实中给予合理的解决,从而保证我国公务员考录制度沿着正确的方向发展,真正达到选贤任能的目的。