Job stress,social support and health amongst shrimp fishermen

Abstract

Samples of shrimp fishermen (n = 211) and land-based workers (n = 99) drawn from a US Gulf Coast community are compared with regard to their degree of exposure to occupational stressors, level of social support, and extent of non-clinical depression and somatization. As hypothesized, shrimp fishermen report significantly greater levels of stressor exposure, support, depression and somatization at the zero-order level. At the multivariate level, with several covariates controlled, shrimpers report greater levels of stressor exposure, support and somatization. A model of the stress process which hypothesizes positive effects of stressors, and direct and indirect negative effects of social support on distress, is evaluated for each group. Occupational stressors predict as hypothesized, but social support does not. An explanation is offered which emphasizes the migratory character of shrimping as an occupation.     

Kendall's tau for serial dependence

The authors show how Kendall's tau can be adapted to test against serial dependence in a univariate time series context. They provide formulas for the mean and variance of circular and noncircular versions of this statistic, and they prove its asymptotic normality under the hypothesis of independence. They present also a Monte Carlo study comparing the power and size of a test based on Kendall's tau with the power and size of competing procedures based on alternative parametric and nonparametric measures of serial dependence. In particular, their simulations indicate that Kendall's tau outperforms Spearman's rho in detecting first‐order autoregressive dependence, despite the fact that these two statistics are asymptotically equivalent under the null hypothesis, as well as under local alternatives.     

Exploring variation in active network size: Constraints and ego characteristics

Studies of active personal networks have primarily focused on providing reliable estimates of the size of the network. In this study, we examine how compositional properties of the network and ego characteristics are related to variation in network size. There was a negative relationship between mean emotional closeness and network size, for both related and unrelated networks. Further, there was a distinct upper bound on total network size. These results suggest that there are constraints both on the absolute number of individuals that ego can maintain in the network, and also on the emotional intensity of the relationships that ego can maintain with those individuals.     

Universal-deterministic and probabilistic hypotheses in operations management research: a discussion paper

Abstract

Based on Karl Popper’s approach to science, this conceptual article aims at promoting a discussion on important issues debated in the OM literature. Our focus is on the different types of hypotheses used in OM investigations and the implications of this for the formulation and testing of theory with an emphasis on case study research. Given that Popper’s methodology calls for an adequate testing of scientific propositions (universal-deterministic or probabilistic), we illustrate how case study research can be used to conduct a severe test of a scientific theory. It is also explained how case studies can be utilized to propose universal-deterministic hypotheses that should then be tested. Our investigation further discusses why it is important to clearly acknowledge the differences between the two types of hypotheses. Otherwise, inadequate research designs, deficient policy advice, and other similar problems, can arise. Topics for future research and discussion are also offered.     

Upgrading local operations for global arbitrage

This study shows that upgrading sales operations in host countries towards production allows MNCs to perform global arbitrage in their networks of foreign subsidiaries and thereby contributes to a strategy of reaping the benefits of multinationality. We predict and find that operation upgrades follow opportunities of improving resource flows in the subsidiary network to exploit the advantages of host countries in tax rates, investment incentives, and technological knowledge across borders. Performance effects on the level of the MNC network give evidence of these benefits from global arbitrage.     

A Social Capital Basis for Environmental Concern: Evidence from Northern New England*

This study, based on a random‐digit‐dialing telephone survey of adults in Maine, New Hampshire, and Vermont, uses ordinary least squares regression to examine a relatively neglected element in the sociological literature on environmental concern, namely, the influence of an individual's social capital on the formation of environmental attitudes. We argue that it is those individuals with a greater diversity of social connections who are most likely to be influenced by ecological perspectives grounded in conservation and environmental protection. Controlling for other theoretically relevant variables, we regress an index of environmental concern that gives special emphasis to environmental‐economic trade‐offs on our measures of relational and community social capital. While confirming much of the earlier work in this area, our model provides evidence that connections to other people play an important role in determining individual concern for the environment. Specifically, the number of respondents' “weak ties”—that is, not their closest relationships—and the average occupational status of respondents' social ties, in general, were both positively correlated with environmental concern. Additionally, one of our three measures of community social capital, the number of visits from friends over the past month, was statistically significant and negatively correlated with environmental concern.     

The effect of MRP lot sizing on actual cumulative lead times in multi-level systems

This study investigates how different lot sizing techniques influence the cumulative lead time for multi-level production-inventory systems controlled by material requirements planning (MRP). Theoretical approaches, a numerical example, as well as simulation are used to analyse and illustrate the combined effect of lot sizing at different product structure levels. It is shown that lot-sizing requirements for more than a single period, such as fixed period requirements, period under quantity, Silver Meal algorithm, as well as economic order quantity will lead to longer actual cumulative lead times than would be expected, when taking the item lead times along the critical path through the product structure into account. Consequently, MRP will underestimate the cumulative lead time and will require a longer planning horizon. We show that the extension of the cumulative lead techniques covering the time is a lot-sizing related phenomenon and cannot be accounted for by, e.g. using safety lead time. Lot-sizing techniques with multi-period coverage will only occasionally provide the 'expected' cumulative lead time. We also show that average and maximum throughput times, as well as throughput time variability increases with increasing time-period coverage of lots.     

Quality of Life,Hegemony, and Social Change in Rural Ireland: W. Bence Jones, 'A Landlord Who Tried to do His Duty'

Numerical indexes of quality of lifeprovide a date-specific representation of society, and a time series extends our grasp of events. However, the social processesundergirding date-specific indexes and therelated intervals in time fail to convey therealities of the human experience. Indicesabstract meaning from events and the people whoparticipate in them.Quality of life can rise and fall, and maymove in both directions in a lifetime. Withinthose processes some people are agents ofchange, a status derived from social positionand wealth. The retrospective appraisal of hisexperiences as a resident landlord is used as aschema for an appraisal of William Bence Jones'role in the evolving quality of life inVictorian Ireland.     

Fiducial prediction intervals

This paper presents an approach for constructing prediction intervals for any given distribution. The approach is based on the principle of fiducial inference. We use several examples, including the normal, binomial, exponential, gamma, and Weibull distributions, to illustrate the proposed procedure.