A Comparison of Survival Function Estimators in the Koziol–Green Model

In this paper, three competing survival function estimators are compared under the assumptions of the so-called Koziol– Green model, which is a simple model of informative random censoring. It is shown that the model specific estimators of Ebrahimi and Abdushukurov, Cheng, and Lin are asymptotically equivalent. Further, exact expressions for the (noncentral) moments of these estimators are given, and their biases are analytically compared with the bias of the familiar Kaplan–Meier estimator. Finally, MSE comparisons of the three estimators are given for some selected rates of censoring.     

Modified minimax estimation of regression coefficients

Working with the linear regression model (1.1) and having the extraneous information (1.2) about regression coefficients the problem exists how to build estimators (1.3) with the risk (1.4) which enable to utilize the known information in order to reduce their risk as compared with the risk (1.6) of the LSE (1.5). Solution of this problem is known for the positive definite matrix T, namely in form for estimators (1.8) and (1.10).First, it is shown that the proposed estimators (2.6),(2.9) and (2.16) based on psedoinversions of the matrix L represent the solution of the problem of the positive semidefinite matrix T=L'L.Further, the problem of interpretability of estimators in the sense of the inequality (3.1) exists; it is shown that all mentioned estimators are at least partially interpretable in the sense of requirements (3.2) or (3.10).     

Estimation with right‐censored observations under a semi‐Markov model

The semi‐Markov process often provides a better framework than the classical Markov process for the analysis of events with multiple states. The purpose of this paper is twofold. First, we show that in the presence of right censoring, when the right end‐point of the support of the censoring time is strictly less than the right end‐point of the support of the semi‐Markov kernel, the transition probability of the semi‐Markov process is nonidentifiable, and the estimators proposed in the literature are inconsistent in general. We derive the set of all attainable values for the transition probability based on the censored data, and we propose a nonparametric inference procedure for the transition probability using this set. Second, the conventional approach to constructing confidence bands is not applicable for the semi‐Markov kernel and the sojourn time distribution. We propose new perturbation resampling methods to construct these confidence bands. Different weights and transformations are explored in the construction. We use simulation to examine our proposals and illustrate them with hospitalization data from a recent cancer survivor study. The Canadian Journal of Statistics 41: 237–256; 2013 © 2013 Statistical Society of Canada     

Hugh George Brennan: Glasgow University’s First Lecturer in Russian

To date little has been known, and less written, about the life of Hugh George Brennan, Glasgow University's first lecturer in Russian. The uncovering of previously unused Russian and British sources throwing fresh light on his life, intellectual development and occupations has made possible a fuller assessment of a significant figure in Glasgow's contribution to Slavonic Studies. Brennan lived and taught in Russia for 20 years. The resulting intense and unusually intimate experience of Russian life probably explains unconventional aspects of his Glasgow appointment. Brennan was an undoubted educational and social success in Russia. Events in the shape of the February Revolution of 1917 forced him to return to Britain. Glasgow's timely offer of a new position was the start of a very different life. This aspect of Brennan's career is reviewed mainly through his commitment to extensive public activities.     

高校心理辅导站建立的初步探析

高校心理辅导站的建立为心理健康教育提供了新的平台,它的优势是显而易见的。本文阐述了心理辅导站建立的意义、定位及作用,并对辅导站的发展瓶颈及对策进行了初步探究。     

The Secondary Traumatic Stress Scale (STSS)

SUMMARY

The Secondary Traumatic Stress Scale (STSS; Bride, Robinson, Yegidis, & Figley, 2004) is an easy to administer 17-itemself-report measure of secondary trauma. Bride et al. (2004) reported a measure of three domains of traumatic stress specifically associated with secondary exposure to trauma: intrusion, avoidance, and arousal. The STSS was reported to have high levels of internal consistency reliability and indicated evidence of convergent, discriminant, and factorial validity. The purpose of this paper is to examine the reliability and validity of the STSS with a national, random sample of mental health social workers. To assess the fit of the data to the three-factor structure proposed by Bride et al., a confirmatory factor analysis was performed on data from 275 social workers who indicated exposure to client trauma. The model fit the data adequately although high factor intercorrelations strongly suggest a unidimensional scale. Subsequent confirmatory factor analysis of a unidimensional scale and a second order factor analysis yielded similar results. Findings indicate the need for further scale validation. Challenges remain for measuring and distinctly differentiating between secondary trauma symptoms of arousal, avoidance, and intrusion. Implications and suggestions for future research are discussed.     

Methods for calculating stationary distribution in linear models of time series

The article deals with methods for computing the stationary marginal distribution in linear models of time series. Two approaches are described. First, an algorithm based on approximation of solution of the corresponding integral equation is briefly reviewed. Then, we study the limit behaviour of the partial sums c ₁ η₁+c ₂ η₂+···+c _n η _n where η _i are i.i.d. random variables and c _i real constants. We generalize procedure of Haiman (1998) [Haiman, G., 1998, Upper and lower bounds for the tail of the invariant distribution of some AR(1) processes. Asymptotic Methods in Probability and Statistics, 45, 723–730.] to an arbitrary causal linear process and relax the assumptions of his result significantly. This is achieved by investigating the properties of convolution of densities.     

Nonparametric regression with cross‐classified responses

In this article, we develop regression models with cross‐classified responses. Conditional independence structures can be explored/exploited through the selective inclusion/exclusion of terms in a certain functional ANOVA decomposition, and the estimation is done nonparametrically via the penalized likelihood method. A cohort of computational and data analytical tools are presented, which include cross‐validation for smoothing parameter selection, Kullback–Leibler projection for model selection, and Bayesian confidence intervals for odds ratios. Random effects are introduced to model possible correlations such as those found in longitudinal and clustered data. Empirical performances of the methods are explored in simulation studies of limited scales, and a real data example is presented using some eyetracking data from linguistic studies. The techniques are implemented in a suite of R functions, whose usage is briefly described in the appendix. The Canadian Journal of Statistics 39: 591–609; 2011. © 2011 Statistical Society of Canada     

我国内地公司ADR与原股的外溢效应研究

本文以14家同时发行H股与ADR,6家同时发行B股与ADR的上市公司为样本,利用GARCH(1,1)-MA(1)模型,探讨ADR与原股报酬波动的外溢效应,以了解我国证券市场与美国证券市场的整合程度。结果发现,我国H股与ADR之间存在报酬波动性的双向相关性,B股与ADR之间存在报酬波动性的单向相关性。本文认为,投资主体差异、市场发展程度不同以及汇率制度是三个影响我国市场和美国市场整合程度的主要因素。