Externalizing Problem Behavior in Adolescence: Parenting Interacting With DAT1 and DRD4 Genes

This study extends previous gene‐by‐environment (G × E) research through design and methodological advances and examines alternative hypotheses of diathesis stress, vantage sensitivity, and differential susceptibility. In a sample of 984 adolescents and their parents, we examined whether effects of parental support, proactive, punitive, harsh punitive, and psychological control on externalizing problem behavior are moderated by adolescents' genotype for the dopamine transporter (DAT1) or receptor D4 (DRD4) gene. Results provided evidence for main effects of parenting behavior and DRD4, and multiple interaction effects of which one survived Bonferroni correction. Adolescents carrying a long DRD4 variant were more susceptible to the effects of parental proactive control on aggression, for better and for worse. Critical considerations were made regarding the complexity of G × E research.     

Commuting Matrices in the Queue Length and Sojourn Time Analysis of MAP/MAP/1 Queues

Queues with Markovian arrival and service processes, i.e., MAP/MAP/1 queues, have been useful in the analysis of computer and communication systems and different representations for their stationary sojourn time and queue length distribution have been derived. More specifically, the class of MAP/MAP/1 queues lies at the intersection of the class of QBD queues and the class of semi-Markovian queues. While QBD queues have a matrix exponential representation for their queue length and sojourn time distribution of order N and N², respectively, where N is the size of the background continuous time Markov chain, the reverse is true for a semi-Markovian queue. As the class of MAP/MAP/1 queues lies at the intersection, both the queue length and sojourn time distribution of a MAP/MAP/1 queue has an order N matrix exponential representation. The aim of this article is to understand why the order N² distributions of the sojourn time of a QBD queue and the queue length of a semi-Markovian queue can be reduced to an order N distribution in the specific case of a MAP/MAP/1 queue. We show that the key observation exists in establishing the commutativity of some fundamental matrices involved in the analysis of the MAP/MAP/1 queue.     

Exploring First Sexual Intercourse,Sexual Orientation,and Sexual Health in Men

In this study the characteristics of the sexual debut of men who have sex with men (MSM) and men who have sex with women (MSW) age 35 or younger (N = 1,201) were compared with one another. We investigated whether these characteristics were associated with sexual health and behavior, and to what extent. Compared to MSW, MSM tended to be older when they had their first sexual intercourse; their first sex partner was older, they felt less ready, and they experienced more pain. We also found that they reported a higher number of lifetime sexual partners and less condom use compared to MSW. Similarities were also ascertained, such as the fact that individuals from both groups do not differ significantly regarding how they experienced their first sexual intercourse emotionally. Many differences between these groups should not always be seen as problematic, whereas others still indicate a need for targeted interventions.     

Body Image in Dyadic and Solitary Sexual Desire: The Role of Encoding Style and Distracting Thoughts

This study explored the link between body image and desire to engage in sexual activity (dyadic and solitary desire) in adult women living in a long-term couple relationship. Moreover, it considered two psychological factors that may underlie such a link: the occurrence of body-related distracting thoughts during sexual activity and encoding style (i.e., the tendency to rely on preexisting internal schemata versus external information at encoding). A total of 53 women (29 to 47 years old) in heterosexual relationships completed questionnaires assessing sexual desire (dyadic, solitary), body image, body-related distracting thoughts during sexual activity, and encoding style. Results showed that poor body image was associated with low dyadic and solitary sexual desire. Body-related distracting thoughts during sexual activity mediated the link between body image and solitary (but not dyadic) sexual desire. Finally, the mediation of body-related distracting thoughts between body image and solitary sexual desire was moderated by encoding style. A negative body image promoted the occurrence of body-related distracting thoughts during sexual activity, especially in internal encoders. Our study highlights the importance of body image, distracting thoughts, and encoding style in women’s solitary sexuality and suggests possible factors that may reduce the impact of those body-related factors in dyadic sexual desire.     

Evaluation of Take‐Home Exposure and Risk Associated with the Handling of Clothing Contaminated with Chrysotile Asbestos

The potential for para‐occupational (or take‐home) exposures from contaminated clothing has been recognized for the past 60 years. To better characterize the take‐home asbestos exposure pathway, a study was performed to measure the relationship between airborne chrysotile concentrations in the workplace, the contamination of work clothing, and take‐home exposures and risks. The study included air sampling during two activities: (1) contamination of work clothing by airborne chrysotile (i.e., loading the clothing), and (2) handling and shaking out of the clothes. The clothes were contaminated at three different target airborne chrysotile concentrations (0–0.1 fibers per cubic centimeter [f/cc], 1–2 f/cc, and 2–4 f/cc; two events each for 31–43 minutes; six events total). Arithmetic mean concentrations for the three target loading levels were 0.01 f/cc, 1.65 f/cc, and 2.84 f/cc (National Institute of Occupational Health and Safety [NIOSH] 7402). Following the loading events, six matched 30‐minute clothes‐handling and shake‐out events were conducted, each including 15 minutes of active handling (15‐minute means; 0.014–0.097 f/cc) and 15 additional minutes of no handling (30‐minute means; 0.006–0.063 f/cc). Percentages of personal clothes‐handling TWAs relative to clothes‐loading TWAs were calculated for event pairs to characterize exposure potential during daily versus weekly clothes‐handling activity. Airborne concentrations for the clothes handler were 0.2–1.4% (eight‐hour TWA or daily ratio) and 0.03–0.27% (40‐hour TWA or weekly ratio) of loading TWAs. Cumulative chrysotile doses for clothes handling at airborne concentrations tested were estimated to be consistent with lifetime cumulative chrysotile doses associated with ambient air exposure (range for take‐home or ambient doses: 0.00044–0.105 f/cc year).     

R&D portfolio selection by using qualitative pairwise comparisons

A new multicriteria decision aid, QualScal, is applied to the problem of selecting an extramural Fisheries R&D portfolio in the Ministry of Agriculture, Fisheries and Food. QualScal has been developed for the situation where the characteristics of the decision alternatives cannot be readily quantified. The decision-maker is only required to state either indifference or preference for each pair of the alternatives. A map representing the preference structure of the decision maker is produced with the aid of an enhanced version of the traditional nonmetric multidimensional scaling procedure, capable of scaling disjoint subsets of alternatives. Averaged results for the group of decision-makers facilitate a discussion to determine a mutually acceptable portfolio.     

Systems thinking and business process redesign: An application to the beer game

Managers are regrettably ignorant of the fact that their business organisations are ‘designable’. But recently, concepts such as business re-engineering and systems thinking, coupled with advances in methods of quantifying business systems, have enabled managers to scrutinise their business systems afresh.Ann van Ackere, Erik Reimer Larsen and John Morecroft use a well-known logistical system — the ‘beer game’ — to illustrate these re-engineering concepts and tools in a multi-stage production and distribution system involving a single brand of beer. This business game raises the fundamental question of why it is so difficult to match shipments and factory production to consumer demand.The authors conclude that such re-design concepts and tools can be applied successfully to full-scale business problems. Systems thinking, modelling and continuous time simulation can provide the framework for carrying the design process from mapping all the way through to redesign. The most effective CEOs of the future will be those who are competent to create corporate design in which employees are allowed to succeed.     

Stakeholder Perspectives on E‐Waste Take‐Back Legislation

In this study, we compare two common forms of product take‐back legislation implementation: (i) manufacturer‐operated systems, where the state imposes certain take‐back objectives on manufacturers, and (ii) state‐operated systems, where manufacturers or consumers finance take‐back through recovery fees. We show that their impacts on different stakeholders, that is, social welfare, manufacturers, consumers, and the environment, can be significantly different and stakeholder preferences for these models vary depending on the operating environments (e.g., production and take‐back costs, and environmental externalities). We also consider the impact of operational externalities such as operating and monitoring costs, and show how they affect stakeholder preferences.     

Vehicle Replacement in the International Committee of the Red Cross

This article studies 4 × 4 vehicle replacement within the International Committee of the Red Cross (ICRC), one of the largest humanitarian organizations. ICRC policy sets the replacement of vehicles at 5 years or 150,000 km, whichever comes first. Using field data collected at the ICRC headquarters and national level we study the ICRC policy. Our results suggest that the organization can make considerable savings by adjusting its replacement policy. This study contributes to the area of logistics and transportation research in humanitarian operations.     

Moderating effects of social support in shiftworking and non-shiftworking nurses

In this study the causal relationships between work characteristics, in terms of job demands and job resources, and both targets’ and perpetrators' reports of workplace bullying, are investigated. In line with the Job Demands-Resources model and the bullying literature, we assumed that both high job demands (i.e. workload, role conflict and job insecurity) and low job resources (i.e. task autonomy, social support and skill utilization) increase bullying over time (i.e. normal causation). Our sample included 177 employees of various establishments of a large Belgian organization. The results of structural equation modelling analyses partially supported our hypothesis. As expected, we found that T1 job demands related positively to targets’ reports of bullying at T2 one year later, and that T1 job resources related negatively to T2 targets’ reports of bullying. Unexpectedly, there was no significant cross-lagged effect of T1 job demands and resources on T2 perpetrator's reports of bullying. No evidence was found for reverse causation or reciprocal effects. Overall, at least for targets, these findings support the validity of the theoretical models postulating a causal link from work characteristics to workplace bullying.