354 research outputs found

    Tearing Out the Income Tax by the (Grass)Roots

    Get PDF
    Landscapes are increasingly fragmented, and conservation programs have started to look at network approaches for maintaining populations at a larger scale. We present an agent-based model of predator–prey dynamics where the agents (i.e. the individuals of either the predator or prey population) are able to move between different patches in a landscaped network. We then analyze population level and coexistence probability given node-centrality measures that characterize specific patches. We show that both predator and prey species benefit from living in globally well-connected patches (i.e. with high closeness centrality). However, the maximum number of prey species is reached, on average, at lower closeness centrality levels than for predator species. Hence, prey species benefit from constraints imposed on species movement in fragmented landscapes since they can reproduce with a lesser risk of predation, and their need for using anti-predatory strategies decreases.authorCount :

    Developmental trajectories of emotional disengagement from schoolwork and their longitudinal associations in England

    Get PDF
    This study identified the varied ways in which emotional disengagement from schoolwork typically developed between 14 and 16 years of age, in the Longitudinal Study of Young People in England. Using growth mixture modelling we found eight main trajectories of (dis)engagement, with four trajectories of either increasing or stable emotional disengagement with schoolwork (41% of the sample). Using propensity score matching to create groups balanced on a wide range of covariates at Wave 1, we compared disengaged students to their engaged counterparts to identify the longitudinal effects of disengagement-trajectory membership on behavioural engagement, psychological wellbeing, substance use, career pathways and achievement. Using linear and binary logistic regressions, we established that students in disengagement trajectories developed lower achievement across compulsory secondary school, and participated less in education and more in employment at age 17 years. In young adulthood (age 19–20 years) they were less likely to attend university and more likely to be unemployed. During secondary schooling, they developed higher levels of substance use and poorer psychological wellbeing, which persisted in the year after compulsory school. However, in young adulthood, the differences in substance use dissipated and students in most of the disengagement trajectories had relatively similar life satisfaction to their counterparts. These findings suggest that students (except perhaps those who became unemployed) were able to develop healthily and happily after leaving the schoolwork environments from which they were emotionally disengaged

    Aerodynamic drag reduction of class 8 heavy vehicles: a full-scale wind tunnel study

    Get PDF

    Pathways to economic well-being among teenage mothers in Great Britain

    Get PDF
    The present study examines pathways to independence from social welfare among 738 teenage mothers, participants of the 1970 British Cohort Study, who were followed up at age 30 years. Using a longitudinal design, a pathway model is tested, examining linkages between family social background, cognitive ability, school motivation, and individual investments in education, as well as work- and family-related roles. The most important factors associated with financial independence by age 30 are continued attachment to the labor market as well as a stable relationship with a partner (not necessarily the father of the child). Pathways to financial independence, in turn, are predicted through own cognitive resources, school motivation, and family cohesion. Implications of findings for policy making are discussed.© 2010 Hogrefe Publishing

    The effectiveness of interventions to change six health behaviours: a review of reviews

    Get PDF
    Background: Several World Health Organisation reports over recent years have highlighted the high incidence of chronic diseases such as diabetes, coronary heart disease and cancer. Contributory factors include unhealthy diets, alcohol and tobacco use and sedentary lifestyles. This paper reports the findings of a review of reviews of behavioural change interventions to reduce unhealthy behaviours or promote healthy behaviours. We included six different health-related behaviours in the review: healthy eating, physical exercise, smoking, alcohol misuse, sexual risk taking (in young people) and illicit drug use. We excluded reviews which focussed on pharmacological treatments or those which required intensive treatments (e. g. for drug or alcohol dependency). Methods: The Cochrane Library, Database of Abstracts of Reviews of Effectiveness (DARE) and several Ovid databases were searched for systematic reviews of interventions for the six behaviours (updated search 2008). Two reviewers applied the inclusion criteria, extracted data and assessed the quality of the reviews. The results were discussed in a narrative synthesis. Results: We included 103 reviews published between 1995 and 2008. The focus of interventions varied, but those targeting specific individuals were generally designed to change an existing behaviour (e. g. cigarette smoking, alcohol misuse), whilst those aimed at the general population or groups such as school children were designed to promote positive behaviours (e. g. healthy eating). Almost 50% (n = 48) of the reviews focussed on smoking (either prevention or cessation). Interventions that were most effective across a range of health behaviours included physician advice or individual counselling, and workplace- and school-based activities. Mass media campaigns and legislative interventions also showed small to moderate effects in changing health behaviours. Generally, the evidence related to short-term effects rather than sustained/longer-term impact and there was a relative lack of evidence on how best to address inequalities. Conclusions: Despite limitations of the review of reviews approach, it is encouraging that there are interventions that are effective in achieving behavioural change. Further emphasis in both primary studies and secondary analysis (e.g. systematic reviews) should be placed on assessing the differential effectiveness of interventions across different population subgroups to ensure that health inequalities are addressed.</p

    Devolving the heartland: making up a new social policy for the 'South East'

    Get PDF
    Devolution appears to challenge the traditional regional and national hierarchies of the UK, but in practice the dominance of the South East of England has been maintained through active state intervention. As social welfare has increasingly been redefined through economic success and access to the labour market, the focus of social policy has shifted accordingly. In this context the South East has been re-imagined not as a symbol of inequality and a potential source of redistribution, but rather as driver of economic prosperity and 'national' (UK) well-being

    What do cyclists need to see to avoid single-bicycle crashes?

    Get PDF
    The number of single-bicycle crash victims is substantial in countries with high levels of cycling. To study the role of visual characteristics of the infrastructure, such as pavement markings, in single-bicycle crashes, a study in two steps was conducted. In Study 1, a questionnaire study was conducted among bicycle crash victims (n = 734). Logistic regression was used to study the relationship between the crashes and age, light condition, alcohol use, gaze direction and familiarity with the crash scene. In Study 2, the image degrading and edge detection method (IDED-method) was used to investigate the visual characteristics of 21 of the crash scenes. The results of the studies indicate that crashes, in which the cyclist collided with a bollard or road narrowing or rode off the road, were related to the visual characteristics of bicycle facilities. Edge markings, especially in curves of bicycle tracks, and improved conspicuity of bollards are recommended. Statement of Relevance: Elevated single-bicycle crash numbers are common in countries with high levels of cycling. No research has been conducted on what cyclists need to see to avoid this type of crash. The IDED-method to investigate crash scenes is new and proves to be a powerful tool to quantify 'visual accessibility'. © 2011 Taylor & Francis

    Is it adaptive to disengage from demands of social change? Adjustment to developmental barriers in opportunity-deprived regions

    Get PDF
    This paper investigates how individuals deal with demands of social and economic change in the domains of work and family when opportunities for their mastery are unfavorable. Theoretical considerations and empirical research suggest that with unattainable goals and unmanageable demands motivational disengagement and self-protective cognitions bring about superior outcomes than continued goal striving. Building on research on developmental deadlines, this paper introduces the concept of developmental barriers to address socioeconomic conditions of severely constrained opportunities in certain geographical regions. Mixed-effects methods were used to model cross-level interactions between individual-level compensatory secondary control and regional-level opportunity structures in terms of social indicators for the economic prosperity and family friendliness. Results showed that disengagement was positively associated with general life satisfaction in regions that were economically devastated and has less than average services for families. In regions that were economically well off and family-friendly, the association was negative. Similar results were found for self-protection concerning domain-specific satisfaction with life. These findings suggest that compensatory secondary control can be an adaptive way of mastering a demand when primary control is not possible
    corecore