The mediating role of work-to-family conflict in the relationship between shiftwork and depression

Abstract

With significant segments of the working population involved in shiftwork, there is the possibility of serious health outcomes. There are two possible pathways to ill health. In the biological pathway the body's circadian rhythms are affected, leading to physiological disturbances and the inability to cope. By contrast, the aim of this study is to elucidate a social pathway by which shiftwork may lead to mental ill health. It examines the mediating influence of work-to-family conflict in the association between shiftwork and depression. Gender differences are also investigated. The sample included 2,931 Canadian respondents with a spouse and at least one child living at home. Close to 28% of respondents were involved in some form of shiftwork. Structural equation modelling supported partial mediation through work-to-family conflict. Further analyses found that mediation was supported in sub-samples of male and female respondents. The results, however, suggest that the experience of shiftwork is quite similar for men and women as no significant differences were found between mediating models. Overall, the findings support the social explanation of the effect of shiftwork on mental health, but they do not rule out other social or biological pathways.     

Kurt Lewin's Field Theory: A Review and Re‐evaluation

Field theory was central to Kurt Lewin's work yet, after his death, interest in it declined significantly until the 1990s when a variant, force field analysis, became widely used. This paper examines the origins, purpose and continuing relevance of field theory. It especially looks at the influences of gestalt psychology, topology and Ernst Cassirer's philosophy of science on its development. It argues that Lewin's attempt to replace conventional topology with his own Lewinian mathematics‐based topology in pursuit of scientific rigour resulted in the undermining of its relevance. The paper also compares force field analysis with Lewin's original conception of field theory and shows that it has significant weaknesses in terms of rigour. It concludes that a return to Lewin's original conception of field theory, based on gestalt psychology and conventional topology, can provide academics and practitioners with a valuable and much‐needed approach to managing change.     

Lower bounds and a tabu search algorithm for the minimum deficiency problem

An edge coloring of a graph G=(V,E) is a function c:E→ℕ that assigns a color c(e) to each edge e∈E such that c(e)≠c(e′) whenever e and e′ have a common endpoint. Denoting S _v (G,c) the set of colors assigned to the edges incident to a vertex v∈V, and D _v (G,c) the minimum number of integers which must be added to S _v (G,c) to form an interval, the deficiency D(G,c) of an edge coloring c is defined as the sum ∑ _v∈V D _v (G,c), and the span of c is the number of colors used in c. The problem of finding, for a given graph, an edge coloring with a minimum deficiency is NP-hard. We give new lower bounds on the minimum deficiency of an edge coloring and on the span of edge colorings with minimum deficiency. We also propose a tabu search algorithm to solve the minimum deficiency problem and report experiments on various graph instances, some of them having a known optimal deficiency.     

Optimal Ordering Policies for Stochastic Inventory Problems with Observed Information Delays

Information delays exist in an inventory system when it takes time to collect, process, validate, and transmit inventory/demand data. A general framework is developed in this paper to describe information flows in an inventory system with information delays. We characterize the sufficient statistics for making optimal decisions. When the ordering cost is linear, the optimality of a state‐dependent base‐stock policy is established even when information flows are allowed to cross over time. Additional insights into the problem are obtained via a comparison between our models and the models with stochastic order lead times. We also show that inventory can substitute for information and vice versa.     

Whither Risk Assessment: New Challenges and Opportunities a Third of a Century After the Red Book

Six multi‐decade‐long members of SRA reflect on the 1983 Red Book in order to examine the evolving relationship between risk assessment and risk management; the diffusion of risk assessment practice to risk areas such as homeland security and transportation; the quality of chemical risk databases; challenges from other groups to elements at the core of risk assessment practice; and our collective efforts to communicate risk assessment to a diverse set of critical groups that do not understand risk, risk assessment, or many other risk‐related issues. The authors reflect on the 10 recommendations in the Red Book and present several pressing challenges for risk assessment practitioners.     

Strategic planning for social and political change

Formalized planning is currently applied to planning for operations and capital investment, planning for products and markets, and occasionally for manpower. However, there is little evidence that companies are producing formal plans and programmes to deal with social and political change. Unfortunately, public opinion is moving against business, action groups inside and outside companies are challenging the authority of management, and public officials and politicians are already framing new laws and regulations. Unless managers begin to get more involved in the framing of these controls they are likely to find laws enacted and enforced by people who have little knowledge or sympathy with business. In this article the author points up the necessity to assess the social and political challenge to their business, and formulate and implement social and political strategies and plans aimed at ensuring the survival and prosperity of their organisations.     

Modeling large electorates with Fourier series, with applications to Nash equilibria in proximity and directional models of spatial competition

 In this paper we introduce harmonic analysis (Fourier series) as a tool for characterizing the existence of Nash equilibria in two-dimensional spatial majority rule voting games with large electorates. We apply our methods both to traditional proximity models and to directional models. In the latter voters exhibit preferences over directions rather than over alternatives, per se. A directional equilibrium can be characterized as a Condorcet direction, in analogy to the Condorcet (majority) winner in the usual voting models, i.e., a direction which is preferred by a majority to (or at least is not beaten by) any other direction. We provide a parallel treatment of the total median condition for equilibrium under proximity voting and equilibrium conditions for directional voting that shows that the former result is in terms of a strict equality (a knife-edge result very unlikely to hold) while the latter is in terms of an inequality which is relatively easy to satisfy. For the Matthews [3] directional model and a variant of the Rabinowitz and Macdonald [7] directional model, we present a sufficiency condition for the existence of a Condorcet directional vector in terms of the odd-numbered components of the Fourier series representing the density distribution of the voter points. We interpret our theoretical results by looking at real-world voter distributions and direction fields among voter points derived from U.S. and Norwegian survey data. Received: 7 July 1995 / Accepted: 14 May 1996     

Production mondialisée et progrès social: le cas du textile et de l'habillement

La fragmentation de la production au sein de réseaux mondiaux n'obéit pas seulement à l'avantage comparatif, mais aussi aux décisions de localisation des entreprises dominantes en fonction de la capacité de négociation des producteurs locaux et du rôle qu'elles leur assignent dans la chaîne de production. Les auteurs examinent les conséquences de cette spécialisation dans le textile et l'habillement, pour vingt‐six pays où l'offre de main‐d'?uvre est abondante, sur la période 1990–2007. L'étude économétrique montre que le secteur ne tire pas toujours bénéfice de l'intégration commerciale: on observe plutôt une association négative entre spécialisation verticale et salaires réels.     

The uncovered set in spatial voting games

In a majority rule voting game, the uncovered set is the set of alternatives each of which can defeat every other alternative in the space either directly or indirectly at one remove. Research has suggested that outcomes under most reasonable agenda processes (both sincere and sophisticated) will be confined to the uncovered set. Most research on the uncovered set has been done in the context of voting games with a finite number of alternatives and relatively little is known about the properties of the uncovered set in spatial voting games.We examine the geometry of the uncovered set in spatial voting games and the geometry of two important subsets of the uncovered set, the Banks set and the Schattschneider set. In particular, we find both general upper and lower limits on the size of the uncovered set, and we give the exact bounds of the uncovered set for situations with three voters. For situations with three voters, we show that the Banks set is identical to the uncovered set.