On pooling data summaries in the absence of interactions “response-by-study”

The standard hypothesis testing procedure in meta-analysis (or multi-center clinical trials) in the absence of treatment-by-center interaction relies on approximating the null distribution of the standard test statistic by a standard normal distribution. For relatively small sample sizes, the standard procedure has been shown by various authors to have poor control of the type I error probability, leading to too many liberal decisions. In this article, two test procedures are proposed, which rely on thet—distribution as the reference distribution. A simulation study indicates that the proposed procedures attain significance levels closer to the nominal level compared with the standard procedure.     

On Block Updating in Markov Random Field Models for Disease Mapping

Gaussian Markov random field (GMRF) models are commonly used to model spatial correlation in disease mapping applications. For Bayesian inference by MCMC, so far mainly single-site updating algorithms have been considered. However, convergence and mixing properties of such algorithms can be extremely poor due to strong dependencies of parameters in the posterior distribution. In this paper, we propose various block sampling algorithms in order to improve the MCMC performance. The methodology is rather general, allows for non-standard full conditionals, and can be applied in a modular fashion in a large number of different scenarios. For illustration we consider three different applications: two formulations for spatial modelling of a single disease (with and without additional unstructured parameters respectively), and one formulation for the joint analysis of two diseases. The results indicate that the largest benefits are obtained if parameters and the corresponding hyperparameter are updated jointly in one large block. Implementation of such block algorithms is relatively easy using methods for fast sampling of Gaussian Markov random fields ( Rue, 2001 ). By comparison, Monte Carlo estimates based on single-site updating can be rather misleading, even for very long runs. Our results may have wider relevance for efficient MCMC simulation in hierarchical models with Markov random field components.     

Conditions for Non-confounding and Collapsibility without Knowledge of Completely Constructed Causal Diagrams

In this paper, we discuss several concepts in causal inference in terms of causal diagrams proposed by Pearl (1993 , 1995a , b ), and we give conditions for non-confounding, homogeneity and collapsibility for causal effects without knowledge of a completely constructed causal diagram. We first introduce the concepts of non-confounding, conditional non-confounding, uniform non-confounding, homogeneity, collapsibility and strong collapsibility for causal effects, then we present necessary and sufficient conditions for uniform non-confounding, homegeneity and collapsibilities, and finally we show sufficient conditions for non-confounding, conditional non-confounding and uniform non-confounding.     

区域发展潜力的评价方法及其应用

阐述了区域可持续发展的涵义 ,并从系统的角度对区域可持续发展进行了分析 ,提出了区域发展潜力的概念。构建了区域发展潜力的评价模型。最后对H市的发展潜力进行了评价     

我国铝工业现状及向海外投资的设想

铝是一种重要的战略金属 ,我国铝工业在产业结构、生产规模、经营方式等方面仍存在某些不足 ,本文针对这种状况 ,提出了发展我国铝业的一些措施 ,并分析了我国铝业向海外投资的可行性。     

多元化计量模式的现实思考--历史成本与公允价值择优并存

多元化计量模式的现实思考——历史成本与公允价值择优并存@谢桂芬$宁波高等专科学校经管系!浙江宁波315010~~     

1955年埃苏武器交易内幕

第二次世界大战后美英一方面为了对抗苏联,把中东拉进全球冷战范围,另一方面又企图通过1950年美英法三国宣言控制对中东的武器供应,进而达到调整、保持该地区政治和军事均势之目的。埃及总统纳赛尔为了抵抗以色列的袭击,在请求美英给埃及提供武器不成的情况下,毅然转向苏联,通过捷克同苏联签订了购买武器的条约。苏埃武器交易使苏联势力进入中东,从而给中东局势带来了深远的影响。     

血管的三维重建

构建了血管的三维重建模型 ,并给出了模型的算法及其求解结果 .     

存在品牌转移者和品牌忠诚者的产品差异模型

分析了存在品牌转移者和忠诚者两类特殊消费群情况下的两阶段水平差异模型，其中品牌转移者在选择产品时只考虑价格因素而不考虑运输成本，品牌忠诚者总是选择某一品牌的产品而不管价格和运输成本。讨论了在两阶段选址－定价博弈模型中纯战略均衡存在的条件。     

并行编程模式及分析

讨论了主从模型、单控制流多数据流、分治策略、数据流水线、投机策略、混合模型六种并行编程模型的结构和工作方式、性能及特点,分析统计了大量应用程序。指出了并行程序设计中,并行编程模式的选择直接影响了并行程序的正确性和效率,而主从模型和单控制流多数据流在整体性能上最优,程序执行效率也最好,是两种最常用的并行编程模型。