Marginal and association regression models for longitudinal binary data with drop‐outs: A likelihood‐based approach

Longitudinal data often contain missing observations, and it is in general difficult to justify particular missing data mechanisms, whether random or not, that may be hard to distinguish. The authors describe a likelihood‐based approach to estimating both the mean response and association parameters for longitudinal binary data with drop‐outs. They specify marginal and dependence structures as regression models which link the responses to the covariates. They illustrate their approach using a data set from the Waterloo Smoking Prevention Project They also report the results of simulation studies carried out to assess the performance of their technique under various circumstances.     

多样性·批评性·学术性－评《文艺湘军百家文库·文艺评论方阵》

《文艺湘军百家文库·文艺评论方阵》及先此出版的《当代湖南文艺评论家选集》丛书,集中汇聚了湖南文学批评50年的主要成果,展示了老中青三代批评家的探寻的风姿。其主要特点突出地表现在异彩纷呈的多样性、真诚鲜明的批评性、科学严谨的学术性等方面。     

The analysis of incomplete data using stochastic covariates

In the development of many diseases there are often associated random variables which continuously reflect the progress of a subject towards the final expression of the disease (failure). At any given time these processes, which we call stochastic covariates, may provide information about the current hazard and the remaining time to failure. Likewise, in situations when the specific times of key prior events are not known, such as the time of onset of an occult tumour or the time of infection with HIV-1, it may be possible to identify a stochastic covariate which reveals, indirectly, when the event of interest occurred. The analysis of carcinogenicity trials which involve occult tumours is usually based on the time of death or sacrifice and an indicator of tumour presence for each animal in the experiment. However, the size of an occult tumour observed at the endpoint represents data concerning tumour development which may convey additional information concerning both the tumour incidence rate and the rate of death to which tumour-bearing animals are subject. We develop a stochastic model for tumour growth and suggest different ways in which the effect of this growth on the hazard of failure might be modelled. Using a combined model for tumour growth and additive competing risks of death, we show that if this tumour size information is used, assumptions concerning tumour lethality, the context of observation or multiple sacrifice times are no longer necessary in order to estimate the tumour incidence rate. Parametric estimation based on the method of maximum likelihood is outlined and is applied to simulated data from the combined model. The results of this limited study confirm that use of the stochastic covariate tumour size results in more precise estimation of the incidence rate for occult tumours.     

Modified cross-validation in density estimation

We propose a new modified (biased) cross-validation method for adaptively determining the bandwidth in a nonparametric density estimation setup. It is shown that the method provides consistent minimizers. Some simulation results are reported on which compare the small sample behavior of the new and the classical cross-validation selectors.     

乐教与儒者的宗教情怀

乐教是理解儒家精神不可忽视的重要方面。乐教扎根于“亲亲”之情,具体体现为与“忧患意识”有别,而与“安”“乐”相协调一致的“怛”和“哀”“悲”之情。此情实质上是超越的天道内化为人的心性而落实下来的生命意义与价值得以呈现的方式。儒者虽深知人生之哀、悲,但以乐入手,解悟和转化现实的人生与宇宙,是一大特色。如此,宗教情怀转化为现实的人生关怀,成为特有的礼乐文明的核心内涵。     

Social Stratification and the Division of Household Labor in Japan: The Effect of Wives' Work on the Division of Labor among Dual-earner Families

Abstract:  This article explores the relationship between social stratification and the division of household labor by examining how the contribution to housework by husbands in dual-earner families varies across the Japanese social stratification structure. First, I review previous studies concerning the determinants of husbands' participation in housework and construct four hypotheses regarding the relative resources explanation, the time constraints explanation, the ideology/sex role explanation, and the alternative manpower explanation. Second, I examine the empirical support for these hypotheses in dual-earner couples and the effect of social stratification on husband's participation in housework, which has not been studied thus far. Third, I investigate the effect of social stratification in more detail. According to the results of TOBIT regressions and other supplementary analyses, the principal findings are as follows:

• 1) 

  the relative resources explanation is not supported;

       

Television and Violence in the Economy of Memory

The present paper aims to consider the cultural function of television as a technology for the creation of a public memory. The television system records past images, preserves them, and broadcasts various historical programs. A viewer owns the public memory jointly, through watching/consuming programs. However, the process of production and consumption of programs is linked with the exclusion of other historical memories from the public space. After all, the creation of public memories in depth is related to social power. Through the analysis in concrete terms of a series of programs of Project X and the second episode of the Nippon Hoso Kyokai (NHK; Japan Broadcasting Corporation) series, Special Edition: Judging War, the relationship between the organization of public memories and social power is explored. Project X depicts the challenges of engineers of middle standing who initiated new industrial and technological developments in the 1960s and 1970s. Special Edition: Judging War is based on coverage of the Women's International War Crimes Tribunal on Japan's Military Sexual Slavery. This program was subjected to revision on the eve of its broadcast. What forms of expression were eliminated? These two programs should help us define more clearly what the Japanese media selects for incorporation into the public memory.     

Physiologically Based Liver Modeling and Risk Assessment

Because of the inherent complexity of biological systems, there is often a choice between a number of apparently equally applicable physiologically based models to describe uptake and metabolism processes in toxicology or risk assessment. These models may fit the particular data sets of interest equally well, but may give quite different parameter estimates or predictions under different (extrapolated) conditions. Such competing models can be discriminated by a number of methods, including potential refutation by means of strategic experiments, and their ability to suitably incorporate all relevant physiological processes. For illustration, three currently used models for steady-state hepatic elimination--the venous equilibration model, the parallel tube model, and the distributed sinusoidal perfusion model--are reviewed and compared with particular reference to their application in the area of risk assessment. The ability of each of the models to describe and incorporate such physiological processes as protein binding, precursor-metabolite relations and hepatic zones of elimination, capillary recruitment, capillary heterogeneity, and intrahepatic shunting is discussed. Differences between the models in hepatic parameter estimation, extrapolation to different conditions, and interspecies scaling are discussed, and criteria for choosing one model over the others are presented. In this case, the distributed model provides the most general framework for describing physiological processes taking place in the liver, and has so far not been experimentally refuted, as have the other two models. These simpler models may, however, provide useful bounds on parameter estimates and on extrapolations and risk assessments.     

Premarital Cohabitation and Housework: Couples in Cross‐National Perspective

The authors examine the effect of premarital cohabitation on the division of household labor in 22 countries. First, women do more routine housework than men in all countries. Second, married couples that cohabited before marriage have a more equal division of housework. Third, national cohabitation rates have equalizing effects on couples regardless of their own cohabitation experience. However, the influence of cohabitation rates is only observed in countries with higher levels of overall gender equality. The authors conclude that the trend toward increasing cohabitation may be part of a broader social trend toward a more egalitarian division of housework.     

A Comparison of Partially Adaptive and Reweighted Least Squares Estimation

The small sample performance of least median of squares, reweighted least squares, least squares, least absolute deviations, and three partially adaptive estimators are compared using Monte Carlo simulations. Two data problems are addressed in the paper: (1) data generated from non-normal error distributions and (2) contaminated data. Breakdown plots are used to investigate the sensitivity of partially adaptive estimators to data contamination relative to RLS. One partially adaptive estimator performs especially well when the errors are skewed, while another partially adaptive estimator and RLS perform particularly well when the errors are extremely leptokur-totic. In comparison with RLS, partially adaptive estimators are only moderately effective in resisting data contamination; however, they outperform least squares and least absolute deviation estimators.