A Generalized QMRA Beta‐Poisson Dose‐Response Model

Quantitative microbial risk assessment (QMRA) is widely accepted for characterizing the microbial risks associated with food, water, and wastewater. Single‐hit dose‐response models are the most commonly used dose‐response models in QMRA. Denoting as the probability of infection at a given mean dose d, a three‐parameter generalized QMRA beta‐Poisson dose‐response model, , is proposed in which the minimum number of organisms required for causing infection, K_min, is not fixed, but a random variable following a geometric distribution with parameter . The single‐hit beta‐Poisson model, , is a special case of the generalized model with K_min = 1 (which implies ). The generalized beta‐Poisson model is based on a conceptual model with greater detail in the dose‐response mechanism. Since a maximum likelihood solution is not easily available, a likelihood‐free approximate Bayesian computation (ABC) algorithm is employed for parameter estimation. By fitting the generalized model to four experimental data sets from the literature, this study reveals that the posterior median estimates produced fall short of meeting the required condition of = 1 for single‐hit assumption. However, three out of four data sets fitted by the generalized models could not achieve an improvement in goodness of fit. These combined results imply that, at least in some cases, a single‐hit assumption for characterizing the dose‐response process may not be appropriate, but that the more complex models may be difficult to support especially if the sample size is small. The three‐parameter generalized model provides a possibility to investigate the mechanism of a dose‐response process in greater detail than is possible under a single‐hit model.     

企业人力资源管理质量评价模型及实证分析

本文针对企业人力资源管理是否存在质量问题及该问题是否值得研究的分歧,基于高绩效工作系统和人力资源管理效能假设,通过案例研究、实地访谈和问卷调查,提出包含技术水平、专业水平和战略人力资源管理3个一阶因子、17个具体指标的企业人力资源管理质量(HRMQ)评价模型,并检验该模型的有效性。实证结果表明,企业HRMQ的标准差系数随着成熟度等级的提高而逐步收敛,企业HRMQ存在客观性。同时,随着企业提高HRMQ,技术水平、专业水平和战略人力资源管理三者之间的变异程度逐渐缩小,高质量企业人力资源管理阶段比低质量阶段更强调管理的一致性,从HRMQ角度验证了平衡计分卡(BSC)思想和方法在企业管理中的普适性。     

我国保险资金运用风险分析

随着保险资金规模的不断扩大,其面临的投资风险也越来越大.分析结果表明,保险资金投资于国债、基础设施建设的风险相对较低;投资于银行存款的风险主要是政府运用利率手段调节宏观经济的结果;而投资于股票市场和证券投资基金的风险非常大.同时,算例分析显示,保险资金应扩大债券类资产的投资份额,慎重选择证券投资基金和股票.     

对《化工原理》中离心泵安装高度计算中有关问题的探讨

本文对教材 《化工原理》 在离心泵安装高度计算中存在的问题进行了归纳和讨论,并提出了相应的观点。     

日本的教育政策与经济发展

战后日本的教育政策,是日本经济高速发展的重要原因之一。日本教育政策的主要方面有：教育先行于经济而发展;为提高国民素质而加大教育投入;注意教育投资的重点和效益;根据经济发展的需要制定人才培养计划。     

Case-deletion Influence Measures for the Data from Multivariate t Distributions

For the data from multivariate t distributions, it is very hard to make an influence analysis based on the probability density function since its expression is intractable. In this paper, we present a technique for influence analysis based on the mixture distribution and EM algorithm. In fact, the multivariate t distribution can be considered as a particular Gaussian mixture by introducing the weights from the Gamma distribution. We treat the weights as the missing data and develop the influence analysis for the data from multivariate t distributions based on the conditional expectation of the complete-data log-likelihood function in the EM algorithm. Several case-deletion measures are proposed for detecting influential observations from multivariate t distributions. Two numerical examples are given to illustrate our methodology.     

“三农”问题的多角度观察与系统性解决

一、“三农”问题的由来“三农”问题的表象是延续数千年历史的小农经济、家庭式生产。2004年末,全国13亿人口中仍有7.57亿乡村人口守在不到20亿亩的耕地上。资源的匮乏,土地产出效率的低下,导致了农民的低收入,2004年农村居民人均纯收入2936元,仅为城镇居民的31%;年末农村绝对贫困人口为2610万人,低收入人口为4977万人。与此形成鲜明对比的一组数据是:2004年,全国共有2201万城镇居民得到政府最低生活保障;年末全国参加基本养老保险、失业保险、医疗保险达到3.83亿人次,而“全国”其实是城镇居民。造成城乡发展失调、“三农”问题日益突出的…     

宗教研究范式的比较:社会事实与经验宗教

通过回顾《宗教生活的基本形式》及《宗教经验之种种:人性之研究》这两本经典,比较了涂尔干的社会事实和詹姆斯的经验宗教这两种宗教研究范式。正确认识和理解这两种研究范式,对今后解读中国社会的宗教现象具有一定的借鉴意义。     

输入强化与阅读教学

阅读是英语专业的一门重要课程。大量的阅读是发展语言能力的一个途经。为了使学生获得大量的可理解的有效阅读 (输入 ) ,在教学中必须掌握好阅读材料的难易度、阅读量和阅读教学方法。并将兴趣和相关因素贯串到这三方面的教学中     

营造和谐的党群干群关系:社会和谐的根本保障

推进党的作风建设,核心是保持党同人民群众的血肉联系。和谐的党群干群关系是我们党长期保持执政地位的重要保证,是我们党的始终追求。当前,社会上仍然存在一些影响党群干群关系和谐的因素。诸如干部工作作风与工作方式,干部的腐败问题等等多种因素的影响,致使一些地方党群干群关系较为紧张,影响了社会的稳定和建设。为此,我们必须采取行之有效的措施,营造和谐的党群干群关系,促进党风政风的好转,促进和谐的社会主义现代化建设。