The role of stress and social support in Sick Building Syndrome

Sick Building Syndrome (SBS) involves seemingly healthy individuals experiencing long-lasting symptoms of physical distress in their work settings and is estimated to exist in 20 to 30% of all work settings in the USA. We examined differences in stress, social support and both physical and psychological symptoms reported by hospital personnel working in known SBS sites in Halifax, Nova Scotia (n = 297) with control employees working in relatively SBS-free settings (n = 228). We found that employees reporting that their health had been affected by the building in which they worked and those complaining of poor air quality were more likely to be found in SBS locations. In addition, those people with higher levels of organizational support and marginally higher levels of union support were also more likely to be found in SBS locations. Further analyses revealed that employees with higher role overload and greater family support, but lower levels of organizational support were more likely to report that their own health had been adversely affected by their place of work. Perceptions of poor air quality were predicted by higher levels of role conflict, role overload, and organizational stress and lower levels of organizational support. These results suggest that SBS may not be solely dependent on environmental factors.     

Supplier–Buyer Negotiation Games: Equilibrium Conditions and Supply Chain Efficiency

In a decentralized supply chain, supplier–buyer negotiations have a dynamic aspect that requires both players to consider the impact of their decisions on future decisions made by their counterpart. The interaction generally couples strongly the price decision of the supplier and the quantity decision of the buyer. We propose a basic model for a repeated supplier–buyer interaction, during several rounds. In each round, the supplier first quotes a price, and the buyer places an order at that price. We find conditions for existence and uniqueness of a well‐behaved subgame‐perfect equilibrium in the dynamic game. When costs are stationary and there are no holding costs, we identify some demand distributions for which these conditions are met, examine the efficiency of the equilibrium, and show that, as the number of rounds increases, the profits of the supply chain increase towards the supply chain optimum. In contrast, when costs vary over time or holding costs are present, the benefit from multi‐period interactions is reduced and after a finite number of time periods, supply chain profits stay constant even when the number of rounds increases.     

Likelihood Estimation and Inference in a Class of Nonregular Econometric Models

We study inference in structural models with a jump in the conditional density, where location and size of the jump are described by regression curves. Two prominent examples are auction models, where the bid density jumps from zero to a positive value at the lowest cost, and equilibrium job‐search models, where the wage density jumps from one positive level to another at the reservation wage. General inference in such models remained a long‐standing, unresolved problem, primarily due to nonregularities and computational difficulties caused by discontinuous likelihood functions. This paper develops likelihood‐based estimation and inference methods for these models, focusing on optimal (Bayes) and maximum likelihood procedures. We derive convergence rates and distribution theory, and develop Bayes and Wald inference. We show that Bayes estimators and confidence intervals are attractive both theoretically and computationally, and that Bayes confidence intervals, based on posterior quantiles, provide a valid large sample inference method.     

2-Distance vertex-distinguishing index of subcubic graphs

This paper addresses the performance of scheduling algorithms for a two-stage no-wait hybrid flowshop environment with inter-stage flexibility, where there exist several parallel machines at each stage. Each job, composed of two operations, must be processed from start to completion without any interruption either on or between the two stages. For each job, the total processing time of its two operations is fixed, and the stage-1 operation is divided into two sub-parts: an obligatory part and an optional part (which is to be determined by a solution), with a constraint that no optional part of a job can be processed in parallel with an idleness of any stage-2 machine. The objective is to minimize the makespan. We prove that even for the special case with only one machine at each stage, this problem is strongly NP-hard. For the case with one machine at stage 1 and m machines at stage 2, we propose two polynomial time approximation algorithms with worst case ratio of \(3-\frac{2}{m+1}\) and \(2-\frac{1}{m+1}\), respectively. For the case with m machines at stage 1 and one machine at stage 2, we propose a polynomial time approximation algorithm with worst case ratio of 2. We also prove that all the worst case ratios are tight.     

Quantile Regression under Misspecification,with an Application to the U.S. Wage Structure

Quantile regression (QR) fits a linear model for conditional quantiles just as ordinary least squares (OLS) fits a linear model for conditional means. An attractive feature of OLS is that it gives the minimum mean‐squared error linear approximation to the conditional expectation function even when the linear model is misspecified. Empirical research using quantile regression with discrete covariates suggests that QR may have a similar property, but the exact nature of the linear approximation has remained elusive. In this paper, we show that QR minimizes a weighted mean‐squared error loss function for specification error. The weighting function is an average density of the dependent variable near the true conditional quantile. The weighted least squares interpretation of QR is used to derive an omitted variables bias formula and a partial quantile regression concept, similar to the relationship between partial regression and OLS. We also present asymptotic theory for the QR process under misspecification of the conditional quantile function. The approximation properties of QR are illustrated using wage data from the U.S. census. These results point to major changes in inequality from 1990 to 2000.     

Pregnancy avoidance and coital behavior

This study proposes a behavioral model that identifies determinants of coital activity in the context of pregnancy avoidance and assesses the relationships using weekly panel data collected on 300 rural married women in Sri Lanka in 1988. We discuss the utility of the design, which is similar to that of an epidemiological surveillance system, for the measurement of coital behavior and pregnancy risk perceptions. Perceptions of pregnancy risk, spousal agreement on sexual relations, menstrual and lactational status, and cycle timing, all measured daily, are found to influence significantly the probability of coitus on that day. The findings suggest that substantial gains in studying fertility regulation are likely from closer investigation of the behavioral connections between motivation for pregnancy avoidance and coital incidence. Comparison of such panel data with those of cross-sectional sample surveys also provides insights into the validity of measures of coital and contraceptive behavior.     

Naturalistic social cognition: Intersubjectivity in same-sex dyads

The research paradigm that Ickes and his colleagues (Ickes, Robertson, Tooke, & Teng, 1986; Ickes & Tooke, 1988) have developed for the study of naturalistic social cognition was used to explore the phenomenon ofintersubjectivity as it naturally occurs in the initial, unstructured interactions of same-sex (male-male and female-female) dyads. The results of two studies revealed evidence of greater similarity (i.e., convergence) in the thought-feeling content of the male dyad members than in that of the female dyad members on measures pertaining to the quality of their reported feelings. These findings were consistent with the assumption that, due to a normatively narrower range of affective involvement in the male-male dyads, the male dyad members were more likely than the female dyad members to monitor closely the emotional tone of their interaction. In direct support of this assumption, there was significantly less nonverbal involvement (i.e., gesturing, smiling, gazing, mutual gaze) in the male-male dyads in both studies, along with corresponding differences in the variability of these behaviors. In addition, the results of both studies revealed serendipitous evidence of greater similarity in the thought-feeling content of the female, than of the male, dyad members on measures pertaining to the degree of metaperspective taking and to thoughts and feelings about other people. The discussion emphasized the need for theorists and researchers in cognitive social psychology to address those genuinelysocial-cognitive (i.e., intersubjective) phenomena that have traditionally been ignored.The authors would like to express their appreciation to Kristine Arnold, Ray Bristow, Robin Klemick, Laurie Luce, Julie Williams, and Mari Wilson for their assistance in coding the data for the studies reported here.