Suchergebnisse

Freshwaters are utterly fascinating. They are the threads that stitch together the landscapes of the Earth with a myriad of two-way exchanges involving chemical substances, and organisms from algae and insects to hippopotami and bears. At the same time they suffer the pollutant consequences of human abuses of the land, and are perhaps the most damaged of the Earth's ecosystems. This book, a completely re-written edition of a text book widely used for the past thirty years, continues a tradition of clear, jargon-free writing, a richness of examples and a passionate celebration of rivers, lakes and wetlands. It pulls no punches in describing the threats to freshwaters, whilst revelling in the richness of their fundamental ecology. It gives equal treatment to polar, cold and warm temperate and tropical systems, so avoiding any bias towards any particular region. It is truly a text book for the world's trainee freshwater ecologists.

The new edition of this established textbook, now with full colour illustration, has been extensively revised and continues to provide a comprehensive, stimulating, readable and authoritative coverage of freshwater habitats, their communities and their functioning, the world over. The work will be of great value to undergraduate and graduate students, fellow researchers and water managers, and the plain language and lack of jargon should make it accessible to anyone interested in the functioning and current state of lakes and rivers. Having taught and researched over fifty years and six continents, Professor Brian Moss makes here extensive use of his personal experience as well as the huge literature now available on freshwaters. This is the fifth edition of his textbook, which, since the first edition in 1980, has steadily evolved to reflect a rapidly changing science and environment. It places increasing emphasis on the role of people in damaging and managing freshwaters as we move into the Anthropocene epoch and face unprecedented levels of climate and other changes, whilst rejoicing in the fascination of what are left of near pristine freshwater ecosystems. Professor Moss retired from the University of Liverpool following a career in Africa, the USA and the UK. He was awarded medals by the International Society for Limnology, of which he was President from 2007 to 2013, and The Institute of Ecology and Environmental Management. He was given The Ecology Institute's Excellence in Ecology Prize in 2009 and the book written for that prize, Liberation Ecology, was awarded the British Ecological Society's best ecology book prize in 2013.

Ponds and small lakes support an extremely rich biodiversity of fascinating organisms. Many people have encountered a few unfamiliar creatures, such as dragonfly nymphs and caddisfly larvae. However, there is a far richer world of microscopic organisms, such as diatoms, desmids and rotifers, which is revealed in this book

This new edition of an established textbook provides a comprehensive and stimulating introduction to rivers, lakes and wetlands, and was written as the basis for a complete course on freshwater ecology. Designed for undergraduate and early postgraduate students who wish to gain an overall view of this vast subject area, this accessible guide to freshwater ecosystems and man's activities will also be invaluable to anyone interested in the integrated management of freshwaters. The author maintains the tradition of clarity and conciseness set by previous editions, and the text is extensively illustrated with photographs and diagrams. Examples are drawn from the author's experience in many parts of the world, and the author continues to stress the human influence. The scientific content of the text has been fully revised and updated, making use of the wealth of data available since publication of the last edition. Professor Brian Moss is a lecturer in Applied Ecology at the University of Liverpool, and has written three previous editions of this well-established textbook.

Abstract
Police misconduct and the location of street crimes and deviance have received much research attention. The location of police misconduct, by contrast, has not. Taking the case of Ireland, where policing underwent significant reform in 2007, police oversight data are mapped to determine the location and nature of complaints and any clustering of police misconduct, particularly in areas of greatest deprivation usually associated with people coming into most frequent contact with police. The implications of the findings for police, police oversight, and existing theories by which geography of deviance is framed are discussed.

Background: Academic probation is a nearly universal but underresearched policy practiced at most postsecondary institutions. Objectives: To evaluate the impact of probation warning letters on students' academic performance. Research design: Employing the inferentially strong regression discontinuity design, we evaluated the impact of two versions of warning letters (U.S. mail and email), noting their impact on next semester grades. Subjects: Probation and nonprobation students at a large, Midwestern college enrolled during two, successive fall–winter semester pairs ( n > 17,000, for each pair). Measures: Fall and winter grade point averages (GPAs) were identified for each individual student in the study sample. Results: Using both parametric and nonparametric analyses, we found that neither delivery method, paper or electronic, had a consistent, significant impact on subsequent GPA or odds of a GPA ≥ 2.0 during the next semester. Four of the eight measures of effect for GPA were small and positive (0.02–0.15; one significant positive outcome), and four were negative (−0.02 to −0.08; one significant negative result). A separate set of analyses that excluded students who took a single course led to further inconsistency in results. Supplementary analyses that excluded students scoring far from the cut-point yielded results consistent with a no-difference conclusion. Our findings also indicated that, after being placed on probation, only a small percentage of students were able to avoid movement to the next stage of academic sanction. Conclusions: Warning letters notifying students of probation status, lacking a staff-focused intervention, had little impact on academic performance.

Purpose. To determine whether prepregnancy weight was associated with children's birth weight, early physical growth, and autism diagnosis. Design. Early Childhood Longitudinal Study–Birth Cohort data. Setting. United States. Subjects. Representative sample of U.S. children followed from birth through kindergarten (n = 4800). Also, a subpopulation of the very low birth weight children was examined (n = 500). Measures. Maternal variables included age and prepregnancy body mass index. Changes in children's height, weight, and head circumference between 9 months and 2 years were used as growth metrics. Children's sex, age, birth weight, and reported autism were also considered. Analysis. Logistic and multinomial logistic models assessed the impact of prepregnancy weight on birth weight and children's subsequent rate of physical growth and autism. Results. Children born to underweight or obese mothers had increased odds of very low birth weight. Very low birth weight was related to rapid height and weight growth and more than twice the likelihood to subsequently be diagnosed with autism. For the subgroup of very low birth weight children, rapid head growth was related to a fivefold increase in the odds of autism. After accounting for the impact birth weight and growth rates, we found prepregnancy weight indirectly impacted autism risk. Conclusion. Being underweight or obese during prepregnancy indirectly increased risk for autism from increased odds of low birth weight and accelerated postnatal growth.

Background: Annually, American colleges and universities provide developmental education (DE) to millions of underprepared students; however, evaluation estimates of DE benefits have been mixed. Objectives: Using a prototypic exemplar of DE, our primary objective was to investigate the utility of a replicative evaluative framework for assessing program effectiveness. Research design: Within the context of the regression discontinuity (RD) design, this research examined the effectiveness of a DE program for five, sequential cohorts of first-time college students. Discontinuity estimates were generated for individual terms and cumulatively, across terms. Subjects: Participants were 3,589 first-time community college students. Measures: DE program effects were measured by contrasting both college-level English grades and a dichotomous measure of pass/fail, for DE and non-DE students. Results: Parametric and nonparametric estimates of overall effect were positive for continuous and dichotomous measures of achievement (grade and pass/fail). The variability of program effects over time was determined by tracking results within individual terms and cumulatively, across terms. Applying this replication strategy, DE's overall impact was modest (an effect size of approximately .20) but quite consistent, based on parametric and nonparametric estimation approaches. A meta-analysis of five RD results yielded virtually the same estimate as the overall, parametric findings. Subset analysis, though tentative, suggested that males benefited more than females, while academic gains were comparable for different ethnicities. Conclusion: The cumulative, within-study comparison, replication approach offers considerable potential for the evaluation of new and existing policies, particularly when effects are relatively small, as is often the case in applied settings.

Purpose. To track changes in U.S. children's early weight status (normal, at-risk, or obese) from infancy through preschool. Design. Patterns of change in individual children's weight status are established using three time points from the Early Childhood Longitudinal Study–Birth cohort. Setting. United States. Subjects. Nationally representative sample of U.S. preschool children surveyed at 9 months (n = 8900), with follow-up at 2 years (n = 7500) and preschool (n = 7000). Measures. Individual children's weight status was determined from Centers for Disease Control and Prevention growth charts at multiple time periods. Analysis. Layered, categorical data analysis of changes in weight status patterns at three time periods during infancy through preschool. Results. Young children whose early weight status was normal tend to retain a normal weight status and not to develop an unfavorable status (at-risk, obese). In contrast, children who were obese at an early age were more likely to have an at-risk or obese weight category at a later age. Overall, both favorable and unfavorable early weight statuses were highly associated with subsequent status at preschool. Conclusion. Early weight status can provide important information relevant for early entry point prevention and treatment of childhood obesity.