Decomposition of tree leaf litter on pavement: implications for urban water quality

Leaf litter may be an important source of nutrients to stormwater and ultimately contribute to eutrophication of surface waters associated with urbanization. Thus, understanding decomposition and nutrient release from leaf litter that falls on impervious surfaces is important for stormwater management. However, few studies have examined leaf litter decomposition in the unique urban environment of the street gutter. We compared decomposition of leaf litter of five street tree species in a parking lot gutter in St. Paul, Minnesota, USA. In contrast to our expectations, comparisons with past studies revealed that litter decomposed more rapidly in the gutter than in nearby natural areas. And decomposition rates were as rapid as those measured in other urban settings (forests and streams), with most species losing 80 % of their initial mass after 1 year. Litter of most species had retained more than half of its initial N and P after 1 year. However, in contrast to N, litter P dynamics largely were uncoupled from litter mass dynamics, with litter P increasing and decreasing unpredictably over the year. Short-term (24 h) laboratory studies revealed that litter had the potential to lose a high fraction of its initial P, with high variation among species (from 27 to 88 %), and a smaller fraction of its initial N (<10 %) via leaching. Thus, street tree species may differ in their potential contributions to nutrients that are released during decomposition. Our results suggest that careful selection of street tree species and timely removal of litterfall have significant potential to reduce nutrient fluxes from streets to storm drains, particularly for P.     

Gender-Based Occupational Segregation and Sex Differences in Sensory,Motor, and Spatial Aptitudes

Research on sex differences in humans documents gender differences in sensory, motor, and spatial aptitudes. These aptitudes, as captured by Dictionary of Occupational Titles (DOT) codes, predict the occupational choices of men and women in the directions indicated by this research. We simulate that eliminating selection on these skills reduces the Duncan index of gender-based occupational segregation by 20 % to 23 % in 1970 and 2012, respectively. Eliminating selection on DOT variables capturing other accounts of this segregation has a smaller impact.     

Evaluating a new test using a reference test with estimated sensitivity and specificity

Methodology is proposed for evaluating a new test using a reference test. Unlike previous methodology, sensitivity and the specificity of the reference test are not assumed to be known; instead they are estimated from data comparing the reference test with a gold standard.     

Reviews

Abstract

Heather Baker reviews The no-nonsense guide to leadership, management, and teamwork; Elizabeth Parang reviews Systematic searching: Practical ideas for improving results; Anne Washington reviews Digital preservation in libraries: Preparing for a sustainable future.     

Disabled Children's Experience of Permanency in the Looked After System

Research with seven local authorities in England provided dataon the ‘care careers’ of 596 foster-children overthree years (Sinclair et al., 2005). One part of this studylooked at the experiences of disabled foster-children comparedto non-disabled foster-children. The research aimed to identifyif there were any particular difficulties in pursuing permanencyfor disabled looked after children. This article introducesa concept developed by the author from this work: the idea thatdisabled children may be at risk of experiencing a ‘reverseladder of permanency’; being less likely than their peersto receive permanent placements such as adoption and returnhome. The results of the study partially supported this hypothesis,reinforcing existing findings and highlighting some new ones.Foster-children with learning but not other impairments wereless likely to be adopted. All disabled children were less likelyto return home and therefore remained in foster-care for longer.Disabled children who were adopted, or who returned home, didso after a greater delay compared to non-disabled children.By contrast, children who were ‘clearly disabled’achieved a greater degree of permanence within the care system.The article concludes by considering the implications of suchfindings for policy and practice.     

Age and gender differences in emotional and behavioural problems during the transition to residential treatment: the Odyssey Project

Utilising a national sample of 1,167 young people in residential treatment, this study explored whether the behav-ioural problems exhibited during the transition to residential treatment varied depending upon the age and gender of the youngsters. Specifically, we asked whether those who were admitted to residential treatment centres (RTCs) aged under 12 had a different set of behavioural problems from those who were 12 years and older when admitted, and whether boys had different characteristics than girls. The 11 scales of the Achenbach Child Behavior Checklist were examined. The results revealed statistically significant patterns of associations by age and gender. As populations shift within agencies and across time, knowledge of the behavioural problems associated with age and gender groups can be used to facilitate agency planning and staff training.