38,338 research outputs found

    Long-term change in benthopelagic fish abundance in the abyssal northeast Pacific Ocean

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    Food web structure, particularly the relative importance of bottom-up and top-down control of animal abundances, is poorly known for the Earth's largest habitats: the abyssal plains. A unique 15-yr time series of climate, productivity, particulate flux, and abundance of primary consumers (primarily echinoderms) and secondary consumers (fish) was examined to elucidate the response of trophic levels to temporal variation in one another. Towed camera sled deployments in the abyssal northeast Pacific (4100 m water depth) showed that annual mean numbers of the dominant fish genus (Coryphaenoides spp.) more than doubled over the period 1989-2004. Coryphaenoides spp. abundance was significantly correlated with total abundance of mobile epibenthic megafauna (echinoderms), with changes in fish abundance lagging behind changes in the echinoderms. Direct correlations between surface climate and fish abundances, and particulate organic carbon (POC) flux and fish abundances, were insignificant, which may be related to the varied response of the potential prey taxa to climate and POC flux. This Study provides a fare opportunity to study the long-term dynamics of an unexploited marine fish population and Suggests a dominant role for bottom-up control in this system

    Systematic Review of the Literature on Black and Minority Ethnic Communities in Sport and Physical Recreation

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    The Carnegie Research Institute was commissioned by Sporting Equals and the Sports Councils to conduct an independent systematic review of the literature on participation in sport and recreation by Black and minority ethnic (BME) communities. The brief was to focus on UK material from the past ten years, to compile an electronic, bibliographic database and use that evidence to assess the policy significance of existing knowledge in the drive to widen and increase participation. Although the field might still be considered under-researched over 300 items were identified. Judgements were made on the quality of the research on the basis of the methodological and theoretical soundness and the credibility of the link between the conclusions and the data. The various items were collated in an electronic, bibliographic database and coded as: substantive research of good quality; related public statistics and policy documents; and other related materials of interest. The research, policy and practice contained in this body of work is set within an expanding national and international framework of policy and legislation concerned with human rights and principles of equality. The Sports Councils and Sporting Equals have played a significant part in this through initiatives like the Equality Standard. They have not been acting in isolation, but have received support from other sports bodies with initiatives both to challenge discrimination and inequality and to promote participation and inclusion. Nonetheless, there still seems to be a measure of disconnection between research, sports policies and equality policies. Indeed, sports policies are sometimes based on limited representations of racism and so are inhibited in the way they address racial equality

    Evaluation of buffer-radius modelling approaches used in forest conservation and planning

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    Spatial modelling approaches are increasingly being used to direct forest management and conservation planning at the landscape scale. A popular approach is the use of buffer-radius methods, which create buffers around distinct forest habitat patches to assess habitat connectivity within anthropogenic landscapes. However, the effectiveness and sensitivity of such methods have rarely been evaluated. In this study, Euclidean and least-cost buffer-radius approaches were used to predict functional ecological networks within the wooded landscape of the Isle of Wight (UK). To parameterize the models, a combination of empirical evidence and expert knowledge was used relating to the dispersal ability of a model species, the wood cricket (Nemobius sylvestris Bosc.). Three scenarios were developed to assess the influence of increasing the amount of spatial and species-specific input data on the model outcomes. This revealed that the level of habitat fragmentation for the model species is likely to be underestimated when few empirical data are available. Furthermore, the least-cost buffer approach outperformed simple Euclidean buffer in predicting presence and absence for the model species. Sensitivity analyses on model performance revealed high sensitivity of the models to variation in buffer distance (i.e. maximum dispersal distance) and permeability of common landscape features such as roads, watercourses, grassland and semi-natural habitat. This indicates that when data are lacking with which to parameterize buffer-radius models, the model outcomes need to be interpreted with caution. This study also showed that if sufficient empirical data are available, least-cost buffer approaches have the potential to be a valuable tool to assist forest managers in making informed decisions. However, least-cost approaches should always be used as an indicative rather than prescriptive management tool to support forest landscape conservation and planning

    Software quality assurance plan for GCS

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    The software quality assurance (SQA) function for the Guidance and Control Software (GCS) project which is part of a software error studies research program is described. The SQA plan outlines all of the procedures, controls, and audits to be carried out by the SQA organization to ensure adherence to the policies, procedures, and standards for the GCS project

    Thermal capacitator design rationale. Part 1: Thermal and mechanical property data for selected materials potentially useful in thermal capacitor design and construction

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    The thermal properties of paraffin hydrocarbons and hydrocarbon mixtures which may be used as the phase change material (PCM) in thermal capacitors are discussed. The paraffin hydrocarbons selected for consideration are those in the range from C11H24 (n-Undecane) to C20H42 (n-Eicosane). A limited amount of data is included concerning other properties of paraffin hydrocarbons and the thermal and mechanical properties of several aluminum alloys which may find application as constructional materials. Data concerning the melting temperature, transition temperature, latent heat of fusion, heat of transition, specific heat, and thermal conductivity of pure and commercial grades of paraffin hydrocarbons are given. An index of companies capable of producing paraffin hydrocarbons and information concerning the availability of various grades (purity levels) is provided
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