A modified false discovery rate multiple-comparisons procedure for discrete data, applied to human immunodeficiency virus genetics

Summary.  To help to design vaccines for acquired immune deficiency syndrome that protect broadly against many genetic variants of the human immunodeficiency virus, the mutation rates at 118 positions in HIV amino-acid sequences of subtype C versus those of subtype B were compared. The false discovery rate (FDR) multiple-comparisons procedure can be used to determine statistical significance. When the test statistics have discrete distributions, the FDR procedure can be made more powerful by a simple modification. The paper develops a modified FDR procedure for discrete data and applies it to the human immunodeficiency virus data. The new procedure detects 15 positions with significantly different mutation rates compared with 11 that are detected by the original FDR method. Simulations delineate conditions under which the modified FDR procedure confers large gains in power over the original technique. In general FDR adjustment methods can be improved for discrete data by incorporating the modification proposed.     

Composition-consistent tournament solutions and social choice functions

This paper introduces a new axiom for choice in preference profiles and tournaments, called composition-consistency. A social choice function is composition-consistent if it is non-sensitive to the cloning of one or several outcomes. The key feature of the composition consistency property is an operation concept called multiple composition product of profiles. The paper provides a brief overview of some social choice functions studied in the literature. Concerning the tournament solutions, it is proved that the Top Cycle, the Slater and the Copeland solutions are not composition-consistent, whereas the Banks, Uncovered Set, TEQ, Minimal Covering Set are composition-consistent. Moreover, we define the composition-consistent hull of a solution as the smallest composition-consistent solution containing . The composition-consistent hulls of the Top cycle and Copeland solutions are specified, and we give some hints about the location of the hull of the Slater set. Concerning social choice functions, it is shown that Kemeny, Borda and Minimax social choice functions are not composition-consistent, whereas the Paretian one is composition-consistent. Moreover, we prove that the latter is the composition-consistent hull of the Borda and Minimax functions.     

Income Diversity,Technology Choice and Agricultural Research Policy in Sub‐Saharan Africa

This article makes an initial analysis of the implications of income diversification for technical change and agricultural research policy in Africa, leading to two insights. First, that the dilution effect of income diversification means that, as the proportion of non‐farm income increases, so must the expected gains from adopting a new agricultural technology. Second, that diversified producers will face disproportionately large transactions costs associated with information acquisition to inform technology choice decisions. Two hypotheses about how diversified producers are likely to react are then explored. Both point to the conclusion that income diversification among the poor is likely to constrain significantly the direct poverty impacts of agricultural research. The policy implications of these findings are then considered.     

It is risky business: can social capital reduce risk-taking behaviours among disadvantaged youth?

This study addresses the gap in the research for sound multidimensional assessment of social capital and its relationship with risk-taking behaviour among youths living in disadvantaged communities. Social capital and adolescent risk-taking outcomes were studied cross-sectionally in 1371 secondary students living in two disadvantaged communities within Australia. First, a multidimensional measure of social capital was developed and tested using confirmatory factor analysis. Then, the associations between social capital and a range of youth risk-taking behaviours were examined using structural equation modelling across five-year groups (Grades 7–12). With a few exceptions, higher levels of social capital and belongingness within the school and community were generally associated with decreases in smoking, alcohol and drug consumption, and physical violence. Some outcomes were more strongly associated with family and peer social capital, while others associated more with neighbour and community social capital, indicating that attempts to build social capital need to be targeted across the whole community. This study supports the notion that social capital can be measured empirically and is beneficial in alleviating many of the detrimental health outcomes commonly associated with risk-taking behaviours during adolescence.     

Professional quality of life of adult protective service workers

Adult Protective Services (APS) workers are exposed to substantial occupational hazards and job stress, but these stressors are underdocumented. Therefore, we sought to describe APS workers’ work environments and responses to occupational hazards and stressors, including compassion fatigue, burnout, and secondary traumatic stress. Survey data were gathered with closed-ended questionnaires administered to APS workers in an urban setting. Virtually all workers (97%) reported exposure to one or more environmental hazards in their work, and 80% reported hazard exposure in the past month. Workers also reported mixed responses to their work environment and to experiences with supervision. A sizable minority (22.7%) was at high risk for burnout, 24.6% were at risk for secondary traumatic stress, and 19.9% reported low compassion satisfaction. The results document multiple stressors in APS work. The APS partner is committed to ongoing efforts to better support its staff, and these findings can inform future efforts to enhance supervisor support and worker self-care, to minimize burnout and secondary traumatic stress.