An individual measure of relative survival

Summary.  Relative survival techniques are used to compare survival experience in a study cohort with that expected if background population rates apply. The techniques are especially useful when cause-specific death information is not accurate or not available as they provide a measure of excess mortality in a group of patients with a certain disease. Whereas these methods are based on group comparisons, we present here a transformation approach which instead gives for each individual an outcome measure relative to the appropriate background population. The new outcome measure is easily interpreted and can be analysed by using standard survival analysis techniques. It provides additional information on relative survival and gives new options in regression analysis. For example, one can estimate the proportion of patients who survived longer than a given percentile of the respective general population or compare survival experience of individuals while accounting for the population differences. The regression models for the new outcome measure are different from existing models, thus providing new possibilities in analysing relative survival data. One distinctive feature of our approach is that we adjust for expected survival before modelling. The paper is motivated by a study into the survival of patients after acute myocardial infarction.     

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.     

试论资产评估折旧与会计折旧的区别

文章针对部分资产评估人员在建筑物折旧问题上存在的错误认识和做法 ,通过分析建筑物折旧的原因和重置成本法评估中折旧的实质 ,从多方面详细比较论述了资产评估折旧与会计折旧的区别     

分振幅薄膜干涉课件的制作

利用电脑对点光源和发光平面的薄膜干涉进行模拟 ,并将其制作成多媒体课件 ,使看上去很复杂的光路图变得简单、清晰 ,使教学具有良好的视觉效果 ,大大增强了课堂的容量     

中西文化差异在翻译中的特殊作用

在翻译中常遇到的难题是中西文化差异。本文从物质文化、社会文化和思想文化三个层面对中西文化差异进行了探讨 ,同时进一步剖析了这种反映在语言层面上的差异及其在翻译中的特殊作用     

文化差异对企业管理绩效的影响--以西部地区为例

本文从西部地区的民族、宗教、语言文字、地域亚文化入手 ,分析文化差异对企业管理中个体行为、企业文化、投资环境的冲击 ,以及对企业管理绩效的影响 ,并针对西部地区文化差异大的事实 ,提出对西部地区的企业管理 ,应实行跨文化管理和跨文化培训     

Nonparametric smoothing in the analysis of air pollution and respiratory illness

While most of epidemiology is observational, rather than experimental, the culture of epidemiology is still derived from agricultural experiments, rather than other observational fields, such as astronomy or economics. The mismatch is made greater as focus has turned to continue risk factors, multifactorial outcomes, and outcomes with large variation unexplainable by available risk factors. The analysis of such data is often viewed as hypothesis testing with statistical control replacing randomization. However, such approaches often test restricted forms of the hypothesis being investigated, such as the hypothesis of a linear association, when there is no prior empirical or theoretical reason to believe that if an association exists, it is linear. In combination with the large nonstochastic sources of error in such observational studies, this suggests the more flexible alternative of exploring the association. Conclusions on the possible causal nature of any discovered association will rest on the coherence and consistency of multiple studies. Nonparametric smoothing in general, and generalized additive models in particular, represent an attractive approach to such problems. This is illustrated using data examining the relationship between particulate air pollution and daily mortality in Birmingham, Alabama; between particulate air pollution, ozone, and SO₂ and daily hospital admissions for respiratory illness in Philadelphia; and between ozone and particulate air pollution and coughing episodes in children in six eastern U.S. cities. The results indicate that airborne particles and ozone are associated with adverse health outcomes at very low concentrations, and that there are likely no thresholds for these relationships.     

产业结构和所有制结构的差异--关于东西部地区经济增长差距的一种解释

改革开放以来 ,西部地区与东部地区经济增长的差距有越控越大的趋势 ,形成这些差距的一个重要原因是双方在产业结构和所有制结构上存在的差异 ,并从实证分析的角度进行了检验。     

英语民族与云南少数民族语用习惯差异

语用学是20世纪70年代兴起的一门独立学科,它越来越受到语言学界的关注。语用学主要研究在特定情景中的特殊话语以及在不同的语言交际环境下如何理解和运用语言。从语用学相关理论的角度,通过对英语和部分少数民族语言的表达习惯比较,可以进一步展示中西方民族文化的差异,从而提高语言学习者的目的语文化意识,更好地实现跨文化交际目的。