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.     

A simulation study of a discrete-time multiserver retrial queue with finite population

In this paper, we deal with a discrete-time multiserver retrial queue with finite population. Firstly, we study the Markov chain at the epochs immediately after slot boundaries making emphasis on the computation of its steady-state distribution. Then, the main performance measures are investigated. Besides, we simulate the waiting time of a customer in the retrial group under three different queueing policies. Some numerical examples are given to illustrate the analysis.     

Optimal scaling of Metropolis algorithms: Heading toward general target distributions

The authors provide an overview of optimal scaling results for the Metropolis algorithm with Gaussian proposal distribution. They address in more depth the case of high‐dimensional target distributions formed of independent, but not identically distributed components. They attempt to give an intuitive explanation as to why the well‐known optimal acceptance rate of 0.234 is not always suitable. They show how to find the asymptotically optimal acceptance rate when needed, and they explain why it is sometimes necessary to turn to inhomogeneous proposal distributions. Their results are illustrated with a simple example.     

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.     

Parent and Nonparent Perception of the Multimodal Infant Cry

This study examined whether perceivers can detect infant distress in the visual and acoustic signals within the cry. Parent and nonparent perceivers rated distress in 3‐, 6‐, 8‐, and 12‐month‐old infants' cries that were manipulated to separate facial, vocal, and bodily action. Mean perceiver ratings differed for high‐ and low‐distress cries at each infant age on the basis of facial and vocal action, but not bodily movement. Perceivers rated the cry sound as more distressed and the cry face as less distressed with increasing infant age. Parents rated the cries as less distressed overall than did nonparents. The results suggest that information about distress is available for perceivers in the crying infant's face and voice.     

Neighborhood Structure,Social Organization,and Number of Short‐Term Sexual Partnerships

We examine the relationship between neighborhood structural characteristics, social organization, and the sexual partnering practices of adults. Analyses of 1990 census and 1995–1997 survey‐based data on Chicago neighborhoods and adult sexual activity reveal for men a number of neighborhood influences on sexual partnering practices. First, residential stability is negatively associated with having a short‐term sexual partner in the last year. Second, neighborhood social ties are positively associated with short‐term sexual partnering in neighborhoods with low levels of collective efficacy—the combination of cohesion and shared expectations for beneficial action among neighbors—but this effect is substantially reduced as collective efficacy increases. Moreover, neighborhood collective efficacy and social ties mediate the effect of residential stability on sexual partnering practices. Neighborhood characteristics were not associated with short‐term sexual partnering for women.     

A “brer rabbit” case for reverse mandated benefits

Reverse mandated benefits is a government-mandated policy that requires employees to provide their employers with benefits that workers would not provide otherwise. Of course, only those benefits would be mandated that are worth more to employers than they cost, as determined by political authorities. My case for such a policy argues that it is at least as sensible as policies mandating that employers provide benefits to their employees that would not be provided otherwise.     

Formalization of grievance procedures: A multi-firm and industry study

This study examines how two aspects of formalization of grievance procedures affect grievance procedure effectiveness: written versus oral presentation of grievance and the level of union and management authorized to resolve grievances at the first step. Several demographic variables were controlled for: size of bargaining unit, percentage of organization represented, number of grievances filed, and industry. A sample of 46 firms, representing a broad cross-section of unionized companies in the private sector, was obtained with the help of the American Arbitration Association. Results indicate that more formal grievance procedures (e.g., written presentation) are positively related to resolution rates at the first step. The number of grievances field and the size of the bargaining unit were positively related to total resolution rates prior to arbitration. We thank the American Arbitration Association for making this study possible.     

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.     

Forced to work and liberated from work

The work-welfare nexus is essential in all social policy regimes. The question is in what situations individuals should be entitled to social welfare benefits and in which situations they should be obliged to work. Social welfare law and administrative practices define mechanisms that separate the deserving poor from people able to work. This article analyses the functions and character of these "separation mechanisms" in Sweden during three periods in history: a) in rural society in the late 19th century; b) in industrial society during the successful years of the Swedish model from World War II until the late 1970s; and c) the present, including the period of welfare retrenchment and reconsideration since the early 1980s. The conclusion is that Swedish social policy has always been strongly work-oriented, but the specific form and content of the work ethic has varied under the influence of different ideologies and handled in different social policy institutions. Under specific conditions the work line has been either generous or restrictive and it has been based on structural attempts to improve the opportunities to work as well as on attempts to strongly pressure the individual to work. The work line of today is seen as an interesting attempt to combine an effort to create good work through improved work conditions and an effort to reinforce elements of work enforcement in the social insurance system.