Difference in Condom Use Between Bear Concordant and Discordant Dyads During the Last Anal Sex Event

The purpose of this study was to understand how bear identity influenced condom use during the last anal sex event. Participants were recruited to complete an online, anonymous self-report survey through bear-related sexual and social networking websites. A total of 1,080 men who identified as gay or bisexual and as a member of the bear community and were 18 years or older completed the survey. Overall, fewer than a third of men reported condom use during the most recent receptive (28%) and insertive (30%) anal sex event. Men in bear concordant pairings were less likely to use a condom during receptive and insertive anal sex compared to those is discordant pairings (p < .05). Findings suggest that bear identity concordance influences condom use during anal sex after accounting for an individual’s relationship to their most recent partner as well as other confounding variables.     

Why are there so few women in information technology? Assessing the role of personality in career choices

Despite increases in female labor force participation, women remain substantially under represented in most scientific and technical fields. The small number of women in engineering, physics, chemistry, computer science and other similar fields has variously been attributed to discrimination, differences in ability or choice. This paper uses a unique data set containing information on vocational interests to examine the determinants of entry in to Information Technology occupations. We show that men and women differ systematically in their interests, and that these differences can account for an economically and statistically large fraction of the occupational gender gap.     

The emergence of Sub-Replacement Family Size Ideals in Europe

Period fertility started to drop significantly below replacement in most Western European countries during the 1970s and 1980s, while most fertility surveys, value studies and opinion polls have found that the number of children considered ideal for society or for one's own family has remained above two children per woman. These surveys have led to the expectation that, sooner or later, period fertility would recover in Europe. The most recent data from the Eurobarometer 2001 survey, however, suggest that in the German-speaking parts of Europe the average ideal family sizes given by younger men and women have fallen as low as 1.7 children. This paper examines the consistency and the credibility of these new findings, which – if they are indeed indications of a new trend – may alter the current discussion about future fertility trends in Europe.     

Can what is right with sociology fix what is wrong with sociology? A view from the “Come-back” generation

Sociology’s fragility, in its latest manifestation, is not a result of controversies over method or theory. The challenge is far more serious than those, for it involves the question of whether the subjects of this new science—human beings themselves have any distinctive features that require a distinctive science to be understood.     

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.     

Major Factors Influencing the Health Impacts from Controlling Air Pollutants with Nonlinear Chemistry: An Application to China

Predicting the human‐health effects of reducing atmospheric emissions of nitrogen oxide (NO_x) emissions from power plants, motor vehicles, and other sources is complex because of nonlinearity in the relevant atmospheric processes. We estimate the health impacts of changes in fine particulate matter (PM_2.5) and ozone concentrations that result from control of NO_x emissions alone and in conjunction with other pollutants in and outside the mega‐city of Shanghai, China. The Community Multiscale Air Quality (CMAQ) Modeling System is applied to model the effects on atmospheric concentrations of emissions from different economic sectors and geographic locations. Health impacts are quantified by combining concentration‐response functions from the epidemiological literature with pollutant concentration and population distributions. We find that the health benefits per ton of emission reduction are more sensitive to the location (i.e., inside vs. outside of Shanghai) than to the sectors that are controlled. For eastern China, we predict between 1 and 20 fewer premature deaths per year per 1,000 tons of NO_x emission reductions, valued at $300–$6,000 per ton. Health benefits are sensitive to seasonal variation in emission controls. Policies to control NO_x emissions need to consider emission location, season, and simultaneous control of other pollutants to avoid unintended consequences.     

EXPONENTIAL‐GROWTH BIAS AND LIFECYCLE CONSUMPTION

Exponential‐growth bias (EGB) is the tendency for individuals to partially neglect compounding of exponential growth. We develop a model wherein biased agents misperceive the intertemporal budget constraint, and derive conditions for overconsumption and dynamic inconsistency. We construct an incentivized measure of EGB in a US‐representative population and find substantial bias, with approximately one third of subjects estimated as the fully biased type. The magnitude of the bias is negatively associated with asset accumulation, and does not respond to a simple graphical intervention.     

Longer Life and Population Growth

Enthusiasm about the prospect of large increases in human life expectancy is often dampened by fears that lower mortality will increase population size, hence population pressure. A simple mathematical model of life-cycle stretching demonstrates that if increased longevity is accompanied by later childbearing, a trend that is already underway, future declines in mortality will not increase population size.