Influence of human immunodeficiency virus infection on neurological impairment: an analysis of longitudinal binary data with informative drop-out

A study to investigate the human immunodeficiency virus (HIV) status on the course of neurological impairment, conducted by the HIV Center at Columbia University, followed a cohort of HIV positive and negative gay men for 5 years and assessed the presence or absence of neurological impairment every 6 months. Almost half of the subjects dropped out before the end of the study for reasons that might have been related to the missing neurological data. We propose likelihood-based methods for analysing such binary longitudinal data under informative and non-informative drop-out. A transition model is assumed for the binary response, and several models for the drop-out processes are considered which are functions of the response variable (neurological impairment). The likelihood ratio test is used to compare models with informative and non-informative drop-out mechanisms. Using simulations, we investigate the percentage bias and mean-squared error (MSE) of the parameter estimates in the transition model under various assumptions for the drop-out. We find evidence for informative drop-out in the study, and we illustrate that the bias and MSE for the parameters of the transition model are not directly related to the observed drop-out or missing data rates. The effect of HIV status on the neurological impairment is found to be statistically significant under each of the models considered for the drop-out, although the regression coefficient may be biased in certain cases. The presence and relative magnitude of the bias depend on factors such as the probability of drop-out conditional on the presence of neurological impairment and the prevalence of neurological impairment in the population under study.     

Impact of Hazardous Substances Regulations on Small Firms in Delaware and New Jersey

Regulations under the 1990 Amendments to the Clean Air Act impose significant requirements on firms handling hazardous chemicals. The nature of the regulations would suggest that small firms, because of limited resources and other structural limitations, would experience more difficulty complying with the regulations than large firms. To understand the difficulties imposed by the regulations on small firms, we interviewed ten small firms in Delaware and New Jersey, states with existing hazardous regulations similar to those being considered by the U.S. Environmental Protection Agency, and evaluated their responses to state regulations. The impacts of the environmental regulations on the firms and on the risk levels of their businesses are discussed. Propositions for research into small firms compliance are developed. Possible means for reducing the regulatory burden on small firms while enhancing regulatory effectiveness are suggested.     

Dual-earner couples and the decision to work less: A conceptual model

This paper examines the factors that affect the decision made by dual-earner couples concerning the possibility of one (or both) partners working a reduced-hours schedule. We rely on a comprehensive review of the literature on part-time work among dual-earner couples and on the factors that affect the decisions couples make about their work hours as well as preliminary findings from our ongoing study to consider two key questions: (1) What factors do dual-earner couples take into account when they consider whether one or both might work a reduced-hours schedule? (2) If the couple decides that one partner will work a reduced-hours schedule, how do they decide which partner reduces the hours of employment? Most previous research has focused on the centrality of gender in the decisions that couples make concerning the hours that they work. However, our review of the literature and the preliminary findings of our current research suggest that there are other factors that affect (directly or indirectly) the couples' decisions related to part-time options. Based on this review we present a new decision-making model for two-earner couples that will have implications for future research and policy initiatives. This paper is particularly timely for several reasons: the number of dual-earner couples continues to increase; there is some indication that more employees would choose to reduce their work hours if that were a viable option; and recently, managers and professional workers have become more vocal about their interest in part-time career options.     

The Continued Importance of Quality Parent–Adolescent Relationships During Late Adolescence

The quality of adolescents' relationships with residential parents has been found to predict many different health and behavioral youth outcomes; strong associations have also been found between these outcomes and family processes, and between relationship quality and family processes. Data from Rounds 1–5 of the National Longitudinal Survey of Youth, 1997 were used to examine hypotheses about the influence of the parent–adolescent relationship on subsequent adolescent mental well‐being and delinquency, as mediated by family processes. Using structural equation modeling, we found that the influence of a positive residential parent–adolescent relationship on better mental well‐being and fewer delinquency was entirely mediated by family routines, parental monitoring, and parental supportiveness, net of sociodemographic controls.     

“毛泽东精神”研究四题

毛泽东思想体系具有层次性,毛泽东精神是毛泽东的智慧、情感、意志、理想、信念、人格的结晶,是毛泽东的思想、理论、诗词、书品、生活和实践中蕴含的最深层的本质。毛泽东精神是中华民族的民族精神在20世纪的集中体现,是振兴中华民族强大的精神动力。加强对毛泽东精神的研究、宣传和弘扬,是人民的呼声,时代的需要,是理论工作者责无旁贷的职责。     

A Comparison of Three-level Orthogonal Arrays in the Presence of a Possible Correlation in Observations

When we want to compare two designs we usually assume the standard linear model with uncorrelated observations. In this paper we use the comparison method proposed by Ghosh & Shen (2006) to compare three level orthogonal arrays with 18, 27 and 36 runs under a possible presence of correlation in observations.     

Survival dilemmas: Case study of an adult child of a schizophrenic parent

This article describes aspects of the treatment of an adult child of a schizophrenic parent. Many theories on irrationality in the family setting illuminate the range of impingement on the child's reality when a parent is disturbed in this way. Current research has absorbed itself in interpretations of data on risk, vulnerability, disorder, and early trauma, which have implications for prevention as well as therapeutic treatment of the adult survivor. Profound effects on Ms. P's early development are elaborated in the therapy, in which the treatment stance is influenced by Kohut's theories of the self, particularly as applied to the establishment within the holding environment of specific transferences that facilitate reconstructive work.     

Application of numerical interval analysis to obtain self-validating results for multivariate probabilities in a massively parallel environment

Conventional computations use real numbers as input and produce real numbers as results without any indication of the accuracy. Interval analysis, instead, uses interval elements throughout the computation and produces intervals as output with the guarantee that the true results are contained in them. One major use for interval analysis in statistics is to get results of high-dimensional multivariate probabilities. With the efforts to decrease the length of the intervals that contain the theoretically true answers, we can obtain results to any arbitrary accuracy, which is demonstrated by multivariate normal and multivariate t integrations. This is an advantage over the approximation methods that are currently in use. Since interval analysis is more computationally intensive than traditional computing, a MasPar parallel computer is used in this research to improve performance.     

The parenting of adolescents in Britain today

In this paper it is noted that increased attention has been paid to the topic of parenting in recent years. However, most of this attention has been concentrated on the parenting of young children, with the parenting of adolescents being largely ignored by both practitioners and academics. The paper reviews the available research on the parenting of teenagers, and shows how this could be of use to those who live with young people. The article concludes with some suggestions for new research, and argues that there is an urgent need for greater support and information for this group of parents.