Probabilistic population projections for countries with generalized HIV/AIDS epidemics

In 2015, the United Nations (UN) issued probabilistic population projections for all countries up to 2100, by simulating future levels of total fertility and life expectancy and combining the results using a standard cohort component projection method. For the 40 countries with generalized HIV/AIDS epidemics, the mortality projections used the Spectrum/Estimation and Projection Package (EPP) model, a complex, multistate model designed for short-term projections of policy-relevant quantities for the epidemic. We propose a simpler approach that is more compatible with existing UN projection methods for other countries. Changes in life expectancy are projected probabilistically using a simple time series regression and then converted to age- and sex-specific mortality rates using model life tables designed for countries with HIV/AIDS epidemics. These are then input to the cohort component method, as for other countries. The method performed well in an out-of-sample cross-validation experiment. It gives similar short-run projections to Spectrum/EPP, while being simpler and avoiding multistate modelling.     

Determinants of executive compensation in small business development centers

We develop and test a model of nonprofit executive compensation based on theories of organizational science, economics, and agency theory. Our sample consisted of 114 directors of small business development centers in the United States. Consistent with our model, we find significant effects for human capital, organizational size, and organizational affiliation. We find tentative support for a significant pay‐for‐performance relationship. We find that when education, tenure, size, performance, and affiliation are held constant, female executives are compensated significantly less than male executives.     

Mortality of American Troops in the Iraq War

We estimate the death rate of United States troops deployed to Iraq from the beginning of the US invasion through 30 September 2006. Eighty percent of the deaths in Iraq were combat‐related. The death rate in Iraq is lower than that of the civilian population of the United States but substantially higher than that of young adults. It is much lower than the death rate of US troops in Vietnam, in part because a much smaller fraction die among those wounded in Iraq. We also estimate relative mortality levels for US troops according to numerous demographic variables through 30 November 2006. The risk of death in Iraq per deployment is shown to be highest for Marines; Naval and Air Force personnel in Iraq have lower death rates than the civilian population of comparable age. Other categories with above‐average mortality in Iraq are enlisted troops, males, younger persons, and Hispanics.     

Altruism and social solidarity: Envisioning a field of specialization

Conclusion This article has presented a vision of what a field of altruism and social solidarity could potentially involve. An additional perspective on the nature of this field and how it could contribute to the discipline and to society is provided by the science of psychology. In the last decade a fundamental new orientation has developed in this discipline, growing from the pioneering work of Martin E.P. Seligman. Generally identified as “positive psychology” it represents a shift from a focus on trying to understand and find solutions to mental illness and various pathologies of thought and behavior in a “disease model” to a focus on human strengths, virtues, and other positive characteristics. This shift in focus is regarded as making a direct contribution to understanding what is best in human emotions and traits and how society can support the psychological flourishing of individuals. This new perspective in turn provides increased awareness of how the problems studied in the disease model can more effectively be prevented (Seligman, 2003, 2005). The importance of this focus on the positive for sociology and a call to action is stated by Seligman (2003): The third pillar of positive psychology is the study of positive institutions and positive communities.     

Compressed Natural Gas Bus Safety: A Quantitative Risk Assessment

This study assesses the fire safety risks associated with compressed natural gas (CNG) vehicle systems, comprising primarily a typical school bus and supporting fuel infrastructure. The study determines the sensitivity of the results to variations in component failure rates and consequences of fire events. The components and subsystems that contribute most to fire safety risk are determined. Finally, the results are compared to fire risks of the present generation of diesel-fueled school buses. Direct computation of the safety risks associated with diesel-powered vehicles is possible because these are mature technologies for which historical performance data are available. Because of limited experience, fatal accident data for CNG bus fleets are minimal. Therefore, this study uses the probabilistic risk assessment (PRA) approach to model and predict fire safety risk of CNG buses. Generic failure data, engineering judgments, and assumptions are used in this study. This study predicts the mean fire fatality risk for typical CNG buses as approximately 0.23 fatalities per 100-million miles for all people involved, including bus passengers. The study estimates mean values of 0.16 fatalities per 100-million miles for bus passengers only. Based on historical data, diesel school bus mean fire fatality risk is 0.091 and 0.0007 per 100-million miles for all people and bus passengers, respectively. One can therefore conclude that CNG buses are more prone to fire fatality risk by 2.5 times that of diesel buses, with the bus passengers being more at risk by over two orders of magnitude. The study estimates a mean fire risk frequency of 2.2 x 10(-5) fatalities/bus per year. The 5% and 95% uncertainty bounds are 9.1 x 10(-6) and 4.0 x 10(-5), respectively. The risk result was found to be affected most by failure rates of pressure relief valves, CNG cylinders, and fuel piping.