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.     

The Impact of Maternal Characteristics and Sensitivity on the Concordance Between Maternal Reports and Laboratory Observations of Infant Negative Emotionality

The moderating role of maternal characteristics and maternal sensitivity on the concordance between maternal reports and laboratory observations of negative emotionality was examined. Participants were 90 primiparous mothers and their infants. Mothers completed questionnaires about remembered care from their own parents and their depressive symptoms prenatally, infant temperament (distress to novelty and distress to limitations), and depressive symptoms postnatally. Mothers and infants participated in a laboratory assessment of infant temperament (distress to novelty and limitations) and maternal sensitivity at 6 months postpartum. Several factors that moderate the degree of concordance between maternal reports and behavioral observations were identified, as predicted. Novelty concordance was higher when mothers reported having their emotional needs met in childhood and low prenatal depressive symptoms. Limitations concordance was higher when mothers were less sensitive during the observational tasks. Methodological and theoretical implications are discussed.     

Joint tests of non-nested models and general error specifications

This paper is concerned with joint tests of non-nested models and simultaneous departures from homoskedasticity, serial independence and normality of the disturbance terms. Locally equivalent alternative models are used to construct joint tests since they provide a convenient way to incorporate more than one type of departure from the classical conditions. The joint tests represent a simple asymptotic solution to the “pre-testing” problem in the context of non-nested linear regression models. Our simulation results indicate that the proposed tests have good finite sample properties.     

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.     

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.     

A magical model to predict individual differences in mood change

We tested a mathematical model of psychological well-being (PWB) with data from a paradigm that included a negative mood induction followed by a positive induction. The propositions from the model encompass the hypothesis that the relative mood prior to either induction has implications for the magnitude of subsequent induction effects, such that relative mood is defined by current mood as a ratio of the prevailing mood that is predicted by the model. The findings confirm the hypothesis that the relative mood at baseline predicts mood change in a nonoverlapping time period, even after control for potentially mediating variables.     

The epidemiology of schizophrenia among Caribbean-born and first- and second-generation migrants in Britain

The study of migrants in their new environments is often a useful means of investigating environmental influences on health. Migrants have been found to develop higher rates of mental illness compared to their counterparts who remain at home. These deleterious effects of migration have been attributed to selection factors and stressful life experiences. Migration from an agricultural and traditional society to an urban industrial society where value systems can be demanding, often leads to role strain and role conflict. These kinds of incongruities are the beginning of a series of stressful experiences that contribute to poor health/mental health status. The extent to which one experiences stress is dependent on a number of factors. First, it depends on the perceived difference between home and the new environment. Second, it depends on the cultural homogeneity of the new environment, that is, the extent to which the migrant is readily assimilated into the new culture or is able to maintain a traditional lifestyle by living in an ethnic enclave, and the psychological resources available to successfully access services in the new environment. This paper examines the rates, incidence, and prevalence of schizophrenia found in Caribbean-born immigrants to Britain, and first- and second-generation people of Caribbean background born in Britain. It is argued that Afro-Caribbean people in England are overrepresented in the diagnosis of schizophrenia. Factors that may contribute to this finding range from unemployment, social disadvantage status, social adversity, racism in the health and criminal justice systems, and misdiagnosis.This paper was completed when the author served as Distinguished Visiting Professor-William Patterson College, Wayne, New Jersey.