ON THE INDEPENDENCE OF THE SAMPLE MEAN AND TRANSLATION-INVARIANT STATISTICS FOR MATRIX NORMAL DISTRIBUTIONS

We present an explicit characterization of the joint dependency structure of an n×p matrix normal random matrix such that the p-dimensional sample mean vector is independent of all translation invariant statistics.     

Optimal Times to Contact Sample Households

Finding a suitable respondent at home is an essential and expensivecomponent of a household survey. This article reports on theresults of a study of the probabilities of finding someone aged14 or older at home and discusses the application of such datato survey design and budgeting.     

Estimation of the cumulative incidence function under multiple dependent and independent censoring mechanisms

Competing risks occur in a time-to-event analysis in which a patient can experience one of several types of events. Traditional methods for handling competing risks data presuppose one censoring process, which is assumed to be independent. In a controlled clinical trial, censoring can occur for several reasons: some independent, others dependent. We propose an estimator of the cumulative incidence function in the presence of both independent and dependent censoring mechanisms. We rely on semi-parametric theory to derive an augmented inverse probability of censoring weighted (AIPCW) estimator. We demonstrate the efficiency gained when using the AIPCW estimator compared to a non-augmented estimator via simulations. We then apply our method to evaluate the safety and efficacy of three anti-HIV regimens in a randomized trial conducted by the AIDS Clinical Trial Group, ACTG A5095.     

An evaluation of the tandem configuration automated guided vehicle system

The performance of a tandem automated guided vehicle (AGV) system is compared with that of conventional AGV track systems. In the tandem system the track is divided into non-overlapping, single-vehicle closed loops. Using simulation it is shown that, because of trips requiring delivery across loops, the tandem system has a higher expected travel time per load and thus a greater average time in system. When the loads are delivered within the original loop only, the tandem system has a lower average time in system than in conventional systems, although the difference is modest. Track layout appears to influence the average time in system much more than docs the dispatching rule invoked. The success of the tandem system is highly dependent on approximately even AGV utilization, which may be difficult to obtain in practice.     

The Transitional Discharge Model: comparing implementation in Canada and Scotland

Effective discharge planning is needed to facilitate clients' transition from psychiatric hospital wards to community care. Previous studies have shown that client outcomes can be improved by using a Transitional Discharge Model (TDM) that includes peer support and an extension of inpatient-practitioner relationships that are introduced prior to discharge. However, countries vary in many ways that may affect implementation of the model. This article describes some of the similarities and differences related to introducing transitional discharge in two countries: Canada and Scotland. It is important to elucidate facilitators and challenges in implementing the TDM to identify and disseminate strategies to aid implementation. Implications for future implementation of the model are also discussed.     

Government Capital,Intimate and Community Social Capital,and Food Security Status in Older Adults with Different Income Levels

Whether government‐based forms of food assistance such as the Supplemental Nutrition Assistance Program (SNAP), communal efforts including food pantries, aid from friends and family, or alternative means such as gardening are the appropriate means to reduce the prevalence of household food insecurity is a continuous source of policy contention. To inform this debate, we examine the relative importance of these forms of food assistance and acquisition to a sample of U.S. older adults from the 2010 Brazos Valley Health Assessment of central Texas households that have been stratified by income eligibility for SNAP, low‐income SNAP ineligibility, and above low income status. To identify how membership in these socioeconomic groups constrains household capacity to acquire sufficient food to maintain an adequate and healthy diet, we explore the varied associations of assets received from government; communal and intimate social networks; and alternative food sources such as gardening, hunting, and fishing with household food security across socioeconomic status, while examining the importance of place of residence on the use of capital assets. SNAP participation was the only specific capital asset associated with all levels of food insecurity for both SNAP‐eligible and ineligible low‐income groups, thus emphasizing the continued importance of food assistance among poverty‐level older adults.     

The Role of Behavioral Theory in Model Development Research with Single Parent Families

In this paper, the authors critically examine the plight of single parent families with young children. Next, they lay out in detail the contributions of the behavioral perspective to practice model development research with single-parent families of children under the age of 12. The authors discuss implications for future theory driven practice model development research with cultural specific single parent families. They believe that future model development research efforts with culturally diverse single parent families will aid in advancing the state of cultural competence research in social work while assisting single parents relieve suffering and enhance child and family well-being.     

Running hard to stand still: Communication and information technology within social work training

Recent years have seen rapid technological changes and these have impacted on social work and social work education. Social work educators struggle to keep pace with these changes. Drawing on the author's own experience, this article outlines some key resources that are available to social work educators and students, reflects on the role of 'Communication and Information Technology' within the social work curriculum, and looks towards future developments in relation to online learning.     

Job queues, discrimination, and affirmative action

If employers have different Becker-type discrimination coefficients for different demographic groups, then the implementation of affirmative action may have a differential impact on those groups. We estimate two vector autoregressive models of the U.S. economy, including the unemployment rates of four demographic groups. We find that a job queue existed before the implementation of affirmative action and that affirmative action changed the ordering of the job queue in manner that had a negative impact on nonwhite males. We find evidence that affirmative action may have increased the unemployment rate of nonwhite males by increasing their duration of unemployment.