Inference on Survival Data with Covariate Measurement Error – An Imputation-based Approach

Abstract.  We propose a new method for fitting proportional hazards models with error-prone covariates. Regression coefficients are estimated by solving an estimating equation that is the average of the partial likelihood scores based on imputed true covariates. For the purpose of imputation, a linear spline model is assumed on the baseline hazard. We discuss consistency and asymptotic normality of the resulting estimators, and propose a stochastic approximation scheme to obtain the estimates. The algorithm is easy to implement, and reduces to the ordinary Cox partial likelihood approach when the measurement error has a degenerate distribution. Simulations indicate high efficiency and robustness. We consider the special case where error-prone replicates are available on the unobserved true covariates. As expected, increasing the number of replicates for the unobserved covariates increases efficiency and reduces bias. We illustrate the practical utility of the proposed method with an Eastern Cooperative Oncology Group clinical trial where a genetic marker, c- myc expression level, is subject to measurement error.     

现代汉语中否定成分后置的"把"字句

一般认为在现代汉语中“把”字句的否定形式以否定词在“把”前出现为正确,但是通过语料收集,发现在实际运用中,也存在另一种以否定词出现在“把”字结构后、动词性成分前的否定形式,称之为否定后置的“把”字句,尽管数量不多,但是作为一种语言现象,却值得研究,有助于对“把”字句的成句规则、结构限制等方面的进一步规范。文章借助焦点理论,从共时和历时两个方面入手,对这种否定成分后置的“把”字句进行考察和分析。     

Score test of homogeneity for survival data

If follow-up is made for subjects which are grouped into units, such as familial or spatial units then it may be interesting to test whether the groups are homogeneous (or independent for given explanatory variables). The effect of the groups is modelled as random and we consider a frailty proportional hazards model which allows to adjust for explanatory variables. We derive the score test of homogeneity from the marginal partial likelihood and it turns out to be the sum of a pairwise correlation term of martingale residuals and an overdispersion term. In the particular case where the sizes of the groups are equal to one, this statistic can be used for testing overdispersion. The asymptotic variance of this statistic is derived using counting process arguments. An extension to the case of several strata is given. The resulting test is computationally simple; its use is illustrated using both simulated and real data. In addition a decomposition of the score statistic is proposed as a sum of a pairwise correlation term and an overdispersion term. The pairwise correlation term can be used for constructing a statistic more robust to departure from the proportional hazard model, and the overdispesion term for constructing a test of fit of the proportional hazard model.     

英语否定对象的判断与翻译误区

本文讨论如何判断英语句子的否定对象,澄清一些理解误区以及汉译时怎样按照汉语习惯进行否定重点的转移翻译。     

试析"否定本体论"的意义

否定本体论与中国传统实学以及西方的各种本体论相比,体现出不少独到之处,尤其是它所蕴含的中国性和当代性,对于人性升华、社会转型以及学术探求来说,均具有积极的意义。     

On the Construction of Nearest–Neighbour Balanced Row–Column Designs

Nearest–neighbour balance is considered a desirable property for an experiment to possess in situations where experimental units are influenced by their neighbours. This paper introduces a measure of the degree of nearest–neighbour balance of a design. The measure is used in an algorithm which generates nearest–neighbour balanced designs and is readily modified to obtain designs with various types of nearest–neighbour balance. Nearest–neighbour balanced designs are produced for a wide class of parameter settings, and in particular for those settings for which such designs cannot be found by existing direct combinatorial methods. In addition, designs with unequal row and column sizes, and designs with border plots are constructed using the approach presented here.     

论巴什拉的科学辩证法

巴什拉的现代科学辩证法的两条基本原理是:否的原理和互补原理。他认为,科学的发展是科学理论、概念的修改、校正、否弃的动态的创造性的过程;这种创造的过程及其动力是在理性和经验的互补中获得的。巴什拉的科学辩证法隐含着陷入唯心主义的危险,但仍有理论价值和现实意义。     

欲望：诗意的“放松”与“离开”——“本体性否定”视角下的人生观

在这个充满诱惑的时代，如何健康地对待欲望而又不是轻视性地超越欲望是一个值得重视的问题。“放松地对待欲望”包涵着对“自然性”的新的理解，而“离开欲望”则是指“不满足于欲望”的“穿越美学”所致。如此，人才能成为一个现代“完整的人”。     

基于Matlab语言的有限元法及其应用

介绍了有限元法的本质特征及用变分试函数法和残值试函数法导出有限元法的过程,给出了在Matlab语言环境下实现有限元法的步骤.利用Matlab语言中的PDE工具箱求解偏微分方程具有简便、快速、可视化程度高等优点,能满足精度要求,并以一个工程实例说明了利用有限元法求解偏微分方程从而解决实际问题的方法.     

二维非稳态晶体生长问题解的稳定性

对在均匀流场作用下的二维非稳态晶体生长控制方程进行了分析,证明了原定解问题的解是稳定的.