PERSUADED UNDER PRESSURE: EVIDENCE FROM THE NATIONAL FOOTBALL LEAGUE

We exploit a natural experiment within each National Football League game, finding the first evidence in professional sports that referees succumb to the pressures of satisfying team personnel in the vicinity of possible violations. Using generalized additive models for binomial outcomes, we show that these sideline‐based differences in penalty rates, which are observed on common but influential penalties including pass interference and holding, peak near the centralized location of players and coaches on the sideline. With sizable interests in referee decisions, coaches and players often try to manipulate referee behavior with verbal and nonverbal communications; such actions appear to be persuasive. (JEL ZO, H3)     

Quality of work and job satisfaction: comparing female part-time work in four European countries

Adding to the debate on the integrative or marginalizing nature of female part-time work, this article provides a comparative analysis of the implications of female part-time work for different intrinsic job quality dimensions and job satisfaction. Drawing on national micro-data from Britain, Germany, the Netherlands, and Sweden, our multivariate analyses show cross-national similarities in terms of lower job learning opportunities for female part-timers. We found a significantly higher incidence of repetitiveness only among Swedish female part-timers and lower degrees of task discretion among British, Dutch, and Swedish women working part-time hours. Female part-timers were either equally satisfied with their work as female full-timers or even more satisfied. This held true also after accounting for the lower intrinsic job quality of part-time work. While women working part-time hours were as affected by their job quality characteristics as were full-timers, we conclude that the shorter hours of work per se provide an important additional source of job satisfaction.     

Household Debt and Adult Depressive Symptoms in the United States

This study used data from Waves 1 (1987–1989) and 2 (1992–1994) of the National Survey of Families and Households in the United States and a series of regression models, some of which included individual-specific fixed effects, to estimate associations of particular types and levels of debt with adult depressive symptoms. Results suggest that household debt is positively associated with greater depressive symptoms. However, this association appears to be driven by short-term (unsecured) debt; we found little evidence of associations with depressive symptoms for mid- or long-term debt. The link between short-term debt and depressive symptoms persisted with alternative estimation strategies, including defining debt in absolute and relative terms. Furthermore, this association was particularly concentrated among 51–64 year-old adults, those with a high school education or less, and those who were not stably married throughout the observation period. These findings suggest that short-term debt may have an adverse influence on psychological wellbeing, particularly for those who are less educated, approaching retirement age, or unmarried.     

Demography of a ground nesting bird in an urban system: are populations self-sustaining?

Urbanization poses threats to earth’s biota, and retention of remnant native habitat in protected areas within expanding urban boundaries may help alleviate threats to wildlife. However, it is unclear for nearly all nonsynanthropic (i.e., not benefiting from an association with humans) species whether vital rates in urban habitats can sustain populations or if populations persist only through immigration from outside the urban boundary. We conducted a three-year study of spotted towhees (Aves: Pipilo maculatus) breeding in four undeveloped parks in Portland, OR, USA, to measure park-specific seasonal reproductive output (F) and annual adult survival (S_A). We developed a stochastic model that combined F and S_A with an estimate of first-year survival to measure population growth rate (λ) in all parks assumed to be closed to immigration. F differed among parks but S_A did not. Relatively high F was possible because many pairs raised >1 brood/season. When combined with empirical estimates of survival through the 30-day period of post-fledging parental care (S_D = 0.645), only 2 of 4 parks were self-sustaining (i.e., λ > 1.0). However, S_D reflected substantial loss of fledglings to domestic cats (Felis catus). Assuming no loss to cats and either partial compensatory or additive mortality of fledglings substantially improved prospects of population persistence for declining (sink) populations. Moreover, allowing low levels of immigration to sinks reversed population declines in most parks even when vital rates were insufficient to maintain populations. Our results suggest that nonsynanthropic bird species can persist in urban landscapes, but also that offspring mortality in the post-fledging period may be a critical determinant of population viability.     

Two-Group Classification Using Neural Networks*

Artificial neural networks are new methods for classification. We investigate two important issues in building neural network models; network architecture and size of training samples. Experiments were designed and carried out on two-group classification problems to find answers to these model building questions. The first experiment deals with selection of architecture and sample size for different classification problems. Results show that choice of architecture and choice of sample size depend on the objective: to maximize the classification rate of training samples, or to maximize the generalizability of neural networks. The second experiment compares neural network models with classical models such as linear discriminant analysis and quadratic discriminant analysis, and nonparametric methods such as k-nearest-neighbor and linear programming. Results show that neural networks are comparable to, if not better than, these other methods in terms of classification rates in the training samples but not in the test samples.     

Urinary Excretion of Chromium Following Ingestion of Chromite-Ore Processing Residues in Humans: Implications for Biomonitoring

Biomonitoring programs for urinary chromium (Cr) typically attempt to evaluate occupational exposure via the inhalation route. This study investigated whether Cr can be detected in the urine of people following the ingestion of soils that contain relatively high concentrations of chromium in chromite ore processing residue (COPR). To evaluate the reasonableness of using urinary monitoring to assess environmental exposure, six volunteers ingested 400 mg of soil/day (low-dose group), two others ingested 2.0 g of soil/day (high-dose group) for 3 consecutive days, and one person ingested a placebo on each of 3 days. The soil and COPR mixture contained concentrations of total chromium (Cr) and hexavalent chromium [Cr(VI)] of 103 ± 20 and 9.3 ± 3.8 mg/kg, respectively. Therefore, the low-dose group ingested 41 μg Cr/day [including 3.7 μg Cr(VI)] and the high-dose group ingested 206 μg Cr/day [including 18.6 μg Cr(VI)] on each of 3 consecutive days. All urine samples were collected and analyzed individually for total Cr on the day prior to dosing, during the 3 days of dosing, and up to the first void 48 h after the last dose. No significant increases in urinary Cr excretion were found when background excretion data were compared with data following each of the 3 days of dosing or in daily mean urine concentrations of the high- vs the low-dose groups. It appears that Cr present in a soil and COPR mixture at Cr doses up to 200 μg/day is not sufficiently bioavailable for biomonitoring of urine to be informative. These results are consistent with previously published findings suggesting that incidental exposure to dusts and soils containing comparable levels of Cr will not result in increased concentrations of Cr in urine.     

Factors associated with 'feeling suicidal': the role of sexual identity

This paper examines factors associated with feeling suicidal in a large sample of urban men in Sydney and Melbourne, aged 18-50, including heterosexual, gay and bisexual men, HIV antibody positive and HIV antibody negative. As in previous research, sexuality (being homosexual or bisexual) was found to be a major predictor of suicidality. The research went some way towards explaining the close relationship between feeling suicidal and sexual orientation. Sexuality interacts with feeling bad in that, once men feel moderately bad/depressed, they are more likely to feel suicidal if they are homosexual or bisexual than if they are heterosexual. In addition, the research found that experience of verbal abuse and physical assault (harassment) increased feeling suicidal for both heterosexual and gay/bisexual men, not just for homosexual men as suggested by previous research, and that social isolation in the form of living alone is a further risk factor. Seeking counseling help and taking sexual risks were also independently associated with feeling suicidal. These actions may result from feeling suicidal rather than the reverse, and their association with feeling suicidal warrants further research. Many of the 46 independent variables examined in the research, including HIV antibody status and closeness to the HIV/ AIDS epidemic, were related to feeling suicidal only through their association with being gay/bisexual. Celibacy and general risk taking were not related to feeling suicidal in this study.