Berry–Esseen type bounds for trimmed U-statistics

Trimmed U  -statistics can be constructed in two different ways: by basing the statistic on a trimmed sample or by averaging the trimmed set of kernel values. Mild conditions are given to ensure the rate of convergence to normality is O(n^-1/2)$\mathrm{O}(n^{-1/2})$ in both cases.     

A multivariate von mises distribution with applications to bioinformatics

Motivated by problems of modelling torsional angles in molecules, Singh, Hnizdo & Demchuk (2002) proposed a bivariate circular model which is a natural torus analogue of the bivariate normal distribution and a natural extension of the univariate von Mises distribution to the bivariate case. The authors present here a multivariate extension of the bivariate model of Singh, Hnizdo & Demchuk (2002). They study the conditional distributions and investigate the shapes of marginal distributions for a special case. The methods of moments and pseudo‐likelihood are considered for the estimation of parameters of the new distribution. The authors investigate the efficiency of the pseudo‐likelihood approach in three dimensions. They illustrate their methods with protein data of conformational angles     

Growing Pains: How Risk Perception and Risk Communication Research Can Help to Manage the Challenges of Global Population Growth

In 2011, the global human population reached 7 billion and medium variant projections indicate that it will exceed 9 billion before 2045. Theoretical and empirical perspectives suggest that this growth could lead to an increase in the likelihood of adverse events (e.g., food shortages, climate change, etc.) and/or the severity of adverse events (e.g., famines, natural disasters, etc.). Several scholars have posited that the size to which the global population grows and the extent to which this growth increases the likelihood of adverse outcomes will largely be shaped by individuals’ decisions (in households, organizations, governments, etc.). In light of the strong relationship between perceived risk and decision behaviors, it is surprising that there remains a dearth of empirical research that specifically examines the perceived risks of population growth and how these perceptions might influence related decisions. In an attempt to motivate this important strand of research, this article examines the major risks that may be exacerbated by global population growth and draws upon empirical work concerning the perception and communication of risk to identify potential directions for future research. The article also considers how individuals might perceive both the risks and benefits of population growth and be helped to better understand and address the related issues. The answers to these questions could help humanity better manage the emerging consequences of its continuing success in increasing infant survival and adult longevity.     

Advances in leader and leadership development: A review of 25 years of research and theory

The development of effective leaders and leadership behavior is a prominent concern in organizations of all types. We review the theoretical and empirical literature on leader and leadership development published over the past 25 years, primarily focusing on research published in The Leadership Quarterly. Compared to the relatively long history of leadership research and theory, the systematic study of leadership development (broadly defined to also include leader development) has a moderately short history. We examine intrapersonal and interpersonal issues related to the phenomena that develop during the pursuit of effective leadership, describe how development emerges with an emphasis on multi-source or 360-degree feedback processes, review longitudinal studies of leadership development, and investigate methodological and analytical issues in leader and leadership development research. Future research directions to motivate and guide the study of leader and leadership development are also discussed.     

The stigma of AIDS: fear of disease and prejudice toward gay men

Three hundred college students were presented with vignettes describing an ill person; the vignettes were identical except the illness was identified as either AIDS or leukemia and the individual was described as either homosexual or heterosexual. After reading one vignette, each subject completed a set of measures sensitive to interpersonal evaluation, prejudicial attitudes, and willingness to interact casually with the portrayed individual. The findings indicate the presence of highly stigmatizing attitudes towards AIDS patients and suggest that the public views AIDS patients and gay persons with similar attitudinal prejudice. The need for greater attention to AIDS by social and behavioral researchers is discussed.     

Spatial pattern analysis of the incidence of aster yellows disease in lettuce

The degree of aggregation of lettuce plants infected by aster yellows phytoplasma (AYP) was investigated in 12 fields from three experiments. Position of diseased and healthy plants was mapped in a 6–9×12-m section of each field; for most analyses, fields were divided into 10-plant quadrats. Mean disease incidence (p) ranged from 0.01 to 0.30. The frequency of diseased plants was described by the beta-binomial distribution, with an index of aggregation (θ) ranging from 0 to 0.17, positively correlated withp, and generally increasing over time within a field. Distance-class analysis revealed a core-cluster size of only a few plants. However, spatial autocorrelations ofp between quadrats were not significant, indicating that the scale of spatial pattern was small, generally less than 10 plants. An overall measure of aggregation was given by the slope parameter of the binary form of the power law, in which the log of the calculated variance is regressed on the log of the theoretical variance for a binomial distribution. The slope was 1.18 and significantly different from 1. Results for this “simple-interest” disease are interpreted in relation to the persistent transmission of AYP by its aster leafhopper vector.     

The timing of falls into poverty after retirement and widowhood

A major concern of workers, even those financially prepared for retirement, is that a small risk of poverty may grow over time. Cross-sectional data showing that older cohorts have higher poverty rates substantiate this concern. Using data from the Retirement History Study, we analyze changes in the hazard of entering poverty as a cohort of elderly couples retire and age and the wives are widowed. The initial fall into poverty among those who were not poor before the husband retired is more closely linked to the event of retirement or widowhood than to the slowly eroding household income over the period of retirement and widowhood. The death of her retired husband puts a wife in economic jeopardy whether this shock occurs one year after his retirement or some years later.     

Demographic change,attendance area adjustment and school system impacts

In the extensive litigation over school board liability for segregated schools, a great deal of attention has been focused on changes in school attendance areas. Evidence presented in several trials suggested that school boards have gerrymandered boundaries to keep some schools black and others white. Even though both district and appeal courts have found violations in attendance zone changes, there has been little other than anecodotal evidence to support these findings. In many cases the areas with the most changes in attendance boundaries are also the areas of rapid racial transition, but correlation does not necessarily mean causation. This case study examines boundary changes in Topeka and suggests that racial change in schools is more directly attributable to demographic shifts than to attendance boundary changes.     

Contraceptive practice in the Philippines: a synthesis

This article puts together all available data on contraceptive prevalence and effectiveness from 1968-83 in an attempt to assess the Philippine family planning program's performance in reducing fertility. 3 indicators of contraceptive effectiveness are discussed -- Pearl pregnancy rates, 12-month continuation rates, and effective protection level. Findings on factors associated with contraceptive prevalence are presented and discussed, with special emphasis on the effects of the Outreach project variables. The argument is that popualtion programs can influence demographic behavior, but the extent of this influence largely depends on the quality of program design and implementation.     

Battered gay men: an exploration of abuse, help seeking, and why they stay

In comparison to a large body of literature about battered heterosexual women and a growing body about battered lesbians, this is one of the first published studies that investigates the experiences of battered gay and bisexual men. Results indicated that these men suffered patterns, forms, and frequencies of physical, emotional, and sexual abuse similar to what has been documented by research on battered heterosexual and lesbian women. Likewise, the most commonly reported reasons for staying--namely, hope for change and love for partner--appear to be universal to the experience of being battered. Unlike battered heterosexual women, respondents in this study were not likely to report that being financially trapped was a major reason why they had remained. HIV-status, however, appears to significantly influence their decision to remain. Moreover, lack of knowledge about domestic violence and the lack of availability of appropriate resources play a significant role in same-gender domestic violence victims' decisions to remain. Like battered lesbians, battered gay men infrequently sought assistance from battered women's services and perceived these services as not helpful. By contrast, individual counselors and agencies who provided individual counselors were rated as quite helpful.