Bayesian inference for a discretely observed stochastic kinetic model

The ability to infer parameters of gene regulatory networks is emerging as a key problem in systems biology. The biochemical data are intrinsically stochastic and tend to be observed by means of discrete-time sampling systems, which are often limited in their completeness. In this paper we explore how to make Bayesian inference for the kinetic rate constants of regulatory networks, using the stochastic kinetic Lotka-Volterra system as a model. This simple model describes behaviour typical of many biochemical networks which exhibit auto-regulatory behaviour. Various MCMC algorithms are described and their performance evaluated in several data-poor scenarios. An algorithm based on an approximating process is shown to be particularly efficient.     

Nonparametric estimation of the conditional distribution function in a semiparametric censorship model

In this paper we propose a new nonparametric estimator of the conditional distribution function under a semiparametric censorship model. We establish an asymptotic representation of the estimator as a sum of iid random variables, balanced by some kernel weights. This representation is used for obtaining large sample results such as the rate of uniform convergence of the estimator, or its limit distributional law. We prove that the new estimator outperforms the conditional Kaplan–Meier estimator for censored data, in the sense that it exhibits lower asymptotic variance. Illustration through real data analysis is provided.     

Communication of risk: health hazards from mobile phones

Summary. Possible health hazards from mobile phones arise from the use of the phones themselves and via the base stations that relay signals. Except for an increase in traffic accidents induced by the use of mobile phones in cars the evidence for a health hazard is at most indirect, but it cannot be entirely dismissed; the phones have not been widely used for sufficiently long for direct epidemiological studies to have high sensitivity for detecting any induced incidence of cancer, for example. The background and evidence are briefly reviewed and the steps taken in the UK to make information widely available described.     

On the Third Law of Demand

The Alchian and Allen theorem predicts that it will be harder to find "good" apples in the State of Washington, a prime apple-growing region, than in, say, New York City, where the addition of shipping charges makes "bad" apples comparatively more expensive. We recast the theorem as a testable proposition by explicitly taking the supply side into account and identifying plausible scenarios in which a fixed cost either has no effect on the relative prices of high and low quality grades of the same good in distant markets or, indeed, causes more of the bad apples to be shipped out.     

Some results on optimality in models with heteroscedastic errors from partial optimum designs

This paper studies optimum designs for linear models when the errors are heteroscedastic. Sufficient conditions are given in order to obtainD-, A- andE-optimum designs for a complete regression model from partial optimum designs for some sub-parameters. A result about optimality for a complete model from the optimality for the submodels is included. Supported by Junta de Andalucía, research group FQM244.     

Pulling together: building a community debriefing team.

1. Research shows that many emergency workers are affected physically and emotionally by critical incident stress. 2. Debriefings conducted by trained team members are an effective method to mitigate the impact of critical incident stress. A debriefing is a structured, time-limited group intervention. 3. Cooperation among community agencies is essential for the development and effective functioning of a critical incident stress debriefing team. 4. Several teams in Illinois have organized to form a Critical Incident Stress Debriefing Network. The Illinois network is part of an international organization composed of critical incident stress debriefing providers.     

Problem gambling and policy advice: The mutability and relative effects of structural,associational and attitudinal variables

Research on gambling has the double mandate of public service and the advancement of science. This paper is meant to carry forward that mandate. Latent in research on the causes of problem gambling is the policy insight that these causes represent different types of phenomena and are unequally mutable to practitioners' efforts to prevent and/or treat problem gambling. By making the issue of mutability manifest in research, findings from research would have more policy relevance and practical import. Data from a 1989 Iowa survey on lottery play and problem gambling are analyzed to illustrate this point. 1,226 respondents were contacted by phone and phone interviews were completed with 1,011 of these 1,226 eligible respondents. With multiple regression, we assessed the contributions of mutable and immutable variables to the explained variance in problem gambling. The results show mutable correlates explain enough variance in problem gambling to recommend their consideration in treatment/prevention. The results also suggest a social as well as a psychological etiology to problem gambling. Future research should, however, do a more complete comparison of social and psychological causes of problem gambling.This research was partially supported by the Iowa Department of Human Services and the National Institute of Mental Health (1 R01 MH50369-01A1). The authors wish to thank Willis Goudy, anonymous readers and the editor of this journal for helpful comments.     

The availability of personal and external coping resources: Thier impact on job stress and employee attitudes during organizational restructuring

This study examines the relationships among personal coping resources, social support, external coping resources, job stressors and job strains in a sample of 110 American Telephone and Telegraph employees undergoing a major organizational restructuring. The study expanded on a model suggested by Ashford (1988) by defining another category of coping resources that employees may draw upon to deal with the stressors and strains which occur during major organizational changes. External coping resources were defined as those which provided employees with a sense of 'vicarious control' in stressful situations. Results indicated that personal coping resources, social support and external coping resources had a direct effect upon job stressor and strain levels. No 'buffering' effect of these coplng resources was found. Hierarchical regression analyses indicated that external coping resources added to the prediction of job stressors and strains even when pertonal coping resources and social support were entered first into the prediction questions.     

Childhood parental loss and adult depression

Previous research demonstrates convincingly that childhood parental deaths and parental divorces have implications for adult well-being as defined by levels of depression, educational attainment, early age at marriage, and risk of divorce. What this research has failed to examine are the interconnections among these outcomes. Specifically, are the socioeconomic and marital outcomes of parental loss implicated in the observed higher levels of depression? This analysis takes a first step in answering this question. Using data from a sample of 1,755 married men and women, I estimated regression models which examine the extent to which adult socioeconomic status and current marital quality mediate and/or modify the loss-depression relationship. Parental divorce was strongly related to socioeconomic and marital outcomes. Furthermore, current marital quality contributed importantly to understanding the higher levels of depressed mood observed among persons from divorced homes. Parental death was much more weakly related to socioeconomic and marital outcomes, and these outcomes played little role in explaining its relationship to depression. Finally, all of these relationships were stronger among women than men. These findings support the utility of life-course approaches to understanding adult mental health.