Joint Initial Stocking and Transshipment—Asymptotics and Bounds

A common problem faced by many firms in their supply chains can be abstracted as follows. Periodically, or at the beginning of some selling season, the firm needs to distribute finished goods to a set of stocking locations, which, in turn, supply customer demands. Over the selling season, if and when there is a supply‐demand mismatch somewhere, a re‐distribution or transshipment will be needed. Hence, there are two decisions involved: the one‐time stocking decision at the beginning of the season and the supply/transshipment decision throughout the season. Applying a stochastic dynamic programming formulation to a two‐location model with compound Poisson demand processes, we identify the optimal supply/transshipment policy and show that the optimal initial stocking quantities can be obtained via maximizing a concave function whereas the contribution of transshipment is of order square‐root‐of T. Hence, in the context of high‐volume, fast‐moving products, the initial stocking quantity decision is a much more important contributor to the overall profit. The bounds also lead to a heuristic policy, which exhibits excellent performance in our numerical study; and we further prove both the bounds and the heuristic policy are asymptotically optimal when T approaches infinity. Extension to multiple locations is also discussed.     

Sport participation and positive development in older persons

In many Western countries, more and more people are living longer. As part of this demographic shift, increasing numbers are participating in Masters sport. In the past, sport was considered important for the development of young people; however, the potential for sport participation to affect positive development across the lifespan is now recognized. The purpose of this paper is to introduce conceptual frameworks from developmental psychology that are being used to understand youths’ positive development through sport, and to explore these frameworks in the context of sport as an avenue for positive development in older persons. To achieve this aim, we outline research on sport participation as it applies to youth development and consider relevant aspects as they broadly apply to development later in life. This discussion highlights the inherent paradox of sport participation—that it has the potential to provide considerable positive growth but also the potential for significant negative consequences. Finally, we explore areas of future research related to positive development in older persons through sport.     

Improving Cancer Dose–Response Characterization by Using Physiologically Based Pharmacokinetic Modeling: An Analysis of Pooled Data for Acrylonitrile-Induced Brain Tumors to Assess Cancer Potency in the Rat

Historically, U.S. regulators have derived cancer slope factors by using applied dose and tumor response data from a single key bioassay or by averaging the cancer slope factors of several key bioassays. Recent changes in U.S. Environmental Protection Agency (EPA) guidelines for cancer risk assessment have acknowledged the value of better use of mechanistic data and better dose–response characterization. However, agency guidelines may benefit from additional considerations presented in this paper. An exploratory study was conducted by using rat brain tumor data for acrylonitrile (AN) to investigate the use of physiologically based pharmacokinetic (PBPK) modeling along with pooling of dose–response data across routes of exposure as a means for improving carcinogen risk assessment methods. In this study, two contrasting assessments were conducted for AN-induced brain tumors in the rat on the basis of (1) the EPA's approach, the dose–response relationship was characterized by using administered dose/concentration for each of the key studies assessed individually; and (2) an analysis of the pooled data, the dose–response relationship was characterized by using PBPK-derived internal dose measures for a combined database of ten bioassays. The cancer potencies predicted for AN by the contrasting assessments are remarkably different (i.e., risk-specific doses differ by as much as two to four orders of magnitude), with the pooled data assessments yielding lower values. This result suggests that current carcinogen risk assessment practices overestimate AN cancer potency. This methodology should be equally applicable to other data-rich chemicals in identifying (1) a useful dose measure, (2) an appropriate dose–response model, (3) an acceptable point of departure, and (4) an appropriate method of extrapolation from the range of observation to the range of prediction when a chemical's mode of action remains uncertain.     

Managing Money in Marriage: Multilevel and Cross‐National Effects of the Breadwinner Role

We examine whether institutionalized practices and beliefs regarding breadwinning roles are associated with the choice of more or less equal money management strategies in marriage. Using cross‐national data from 21 country contexts in the International Social Survey Programme and multilevel modeling, we find that in contexts of shared breadwinning, there is a greater likelihood of shared management of money, controlling for the relative income contribution of each spouse. We also find some evidence that the effect of spouses’ relative income contributions diminishes in contexts of shared breadwinning. Our analysis comparing women’s and men’s money management is consistent with previous research indicating that women’s management may be more work than power.     

Cross national study of perceived service quality in long-term care facilities

This cross-national study of 306 nursing home residents in the United States and the United Kingdom examines the similarities and differences in their evaluation of service quality. Service quality was defined as the differences between expectations about the service and actual perceptions of the service delivered in terms of five dimensions: tangibles, assurance, empathy, reliability and responsiveness. The SERVQUAL instrument was used to measure service quality. The two groups differed in their expectations for quality and their perceptions of service quality: US residents' ratings were lower in all respects.     

Can a team have too much cohesion? The dark side to network density

The goal of most work teams is high performance. Prior studies suggest that performance within work groups is influenced by that group’s social network topology. Research has generally revealed to date that group cohesion (i.e., network density) is positively related to team performance under certain conditions. However, more recent research has indicated that this is not the full story. Recent research suggests that an inverse curvilinear relationship exists between social network measures (of which group cohesion is one) and team performance. In response to the need for understanding this relationship more fully, and leveraging the promising new insights that can be garnered with the use of social network analysis (SNA), this study employs SNA as a tool to explore the structural cohesiveness of teams of travel agents. This research extends our understanding of the relationship between intragroup social network relations and team performance by confirming an inverse curvilinear relationship exists between group cohesion and team performance. This paper leverages email communication to determine the social networks of each team, and then examines such in light of team performance. In total, an analysis of more than 7 million emails was undertaken. This study was conducted with work teams within a service organization. Each team in the study carries out the same tasks, i.e., identical task contingency, yet represents a distinct unit of analysis. The study confirms that social network topology is a valuable predictor of team performance and confirms that, like so many other social network measures, group cohesion and team performance share an inverse ‘U’ shaped relationship, not strictly a positive one as previously posited.