Loss functions for estimation of extrema with an application to disease mapping

It is often of interest to find the maximum or near maxima among a set of vector‐valued parameters in a statistical model; in the case of disease mapping, for example, these correspond to relative‐risk “hotspots” where public‐health intervention may be needed. The general problem is one of estimating nonlinear functions of the ensemble of relative risks, but biased estimates result if posterior means are simply substituted into these nonlinear functions. The authors obtain better estimates of extrema from a new, weighted ranks squared error loss function. The derivation of these Bayes estimators assumes a hidden‐Markov random‐field model for relative risks, and their behaviour is illustrated with real and simulated data.     

Values and Vegetarianism: An Exploratory Analysis1

The American diet has changed substantially over the last few decades. These changes provide a test for social theory and have substantial effects on the demand for various food products, thus impacting U.S. agriculture. In this paper a rapidly growing dietary choice—vegetarianism—is explored. Prevalence of various forms of vegetarianism is estimated in a representative sample of a suburban population and factors that influence choice of a vegetarian diet are examined. About 7 percent of the sample report they are vegetarians. The prevalence of vegetarianism is not influenced by age, gender, or education, but individuals holding traditional values are less likely to be vegetarian than others. There also is some evidence mat individuals holding altruistic values are more likely than others to be vegetarians.     

Pollutant Ground Concentrations of Nonneutrally Buoyant Particles

A methodology is suggested for the estimation of the mass density and the cumulative ground deposition of a nonvolatile, nonneutrally buoyant, air pollutant (liquid or solid) released from a polluted column (following an explosion caused during routine operation in, e.g., the chemical industry or due to any kind of hostile act) and deposited on the ground via gravitational settling. In many cases, the deposited mass due to gravitational settling constitutes a significant fraction of the original inventory released from the source. Implementation of the methodology in preliminary risk assessments can serve as an efficient tool for emergency planning for both immediate and long‐term measures such as evacuation and decontamination. The methodology considers, inter alia, an estimation of the critical particle diameter, particle size, and mass distributions along the polluted column. This methodology was developed to apply in rural regions since proper application of relevant meteorological input data can be accomplished mainly for such areas.     

Dynamic modelling of long-term care decisions

This paper describes and analyzes research on the dynamics of long-term care and the policy relevance of identifying the sources of persistence in caregiving arrangements (including the effect of dynamics on parameter estimates, implications for family welfare, parent welfare, child welfare, and cost of government programs). We discuss sources and causes of observed persistence in caregiving arrangements including inertia/state dependence (confounded by unobserved heterogeneity) and costs of changing caregivers. We comment on causes of dynamics including learning/human capital accumulation; burnout; and game-playing. We suggest how to deal with endogenous geography; dynamics in discrete and continuous choices; and equilibrium issues (multiple equilibria, dynamic equilibria). We also present an overview of commonly used longitudinal data sets and evaluate their relative advantages/disadvantages. We also discuss other data issues related to noisy measures of wealth and family structure. Finally, we suggest some methods to handle econometric problems such as endogeneous geography.     

The behavioural wedge

When nations fail to agree, can individual citizens make a difference? The third of our post-Copenhagen features is by Jonathan Gilligan, Thomas Dietz, Gerald T. Gardner, Paul C. Stern , and Michael P. Vandenbergh . They look at the effects that voluntary actions by individuals can have, and at the policies that can best encourage such actions.     

Health belief factors and dispositional optimism as predictors of STD and HIV preventive behavior

Identifying factors predictive of youth's engaging in preventive behaviors related to sexually transmitted diseases (STDs) and HIV remains a prominent public health concern. The utility of the Health Belief Model (HBM) continues to be suggested in identifying preventive behaviors. This study sought to examine the full HBM, including self-efficacy, with regard to STD and HIV preventive behavioral intentions in college students. Self-efficacy was identified as the primary predictor for each of the behavioral intentions (condom use, STD testing, and HIV testing), whereas response efficacy was only predictive of testing intentions. Inconsistent with HBM assumptions, perceived HIV severity was negatively related to HIV testing intentions. Students who perceived HIV as high in severity were less likely to intend to obtain HIV testing. Overall, the utility of the HBM in predicting college students' sexual preventive behavior was unsupported. An argument for a change in the direction of research, away from the continued emphasis on the study of cognitive variables, is made.     

Digital Inequality and Place: The Effects of Technological Diffusion on Internet Proficiency and Usage across Rural,Suburban, and Urban Counties*

Recently researchers have made efforts to reconceptualize digital inequality into discrete levels. These levels reflect access to and diffusion of technologies, proficiency in Internet usage, and propensity to take advantage of the opportunities afforded by information and communication technologies for assistance in daily life. We assess the utility of this approach for studying digital inequality across rural, suburban, and urban counties. Based on data from a 2005 nationally representative random sample telephone survey of 2,185 adults, the results provide mixed support for using this approach to studying digital inequality. In particular, we find that rural residents use Internet technologies less for assistance in helping with economics and other daily activities when compared with individuals from suburban and urban areas; however, our results suggest that this relationship is the product of the slow diffusion of advanced technologies to rural areas. The implications of these findings for understanding this under‐theorized form of inequality are discussed, and we make contributions to this literature through empirically addressing issues of digital capital.