4,343 research outputs found

    Photovoltaic conversion of laser power to electrical power

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    Photovoltaic laser to electric converters are attractive for use with a space-based laser power station. The results of modeling studies for a silicon vertical junction converter used with a Nd laser are given. A computer code was developed for the model and this code was used to conduct a parametric study for a Si vertical junction converter consisting of one p-n junction irradiated with a Nd laser. These calculations predict an efficiency over 50 percent for an optimized converter

    Protocol for developing core outcome sets for evaluation of psychosocial interventions for children and families with experience or at risk of child maltreatment or domestic abuse

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    Introduction Recognition that child maltreatment (CM) and domestic violence and abuse (DVA) are common and have serious and long-term adverse health consequences has resulted in policies and programmes to ensure that services respond to and safeguard children and their families. However, high-quality evidence about how services can effectively intervene is scant. The value of the current evidence base is limited partly because of the variety of outcomes and measures used in evaluative studies. One way of addressing this limitation is to develop a core outcome set (COS) which is measured and reported as a minimum standard in the context of trials and other types of evaluative research. The study described in this protocol aims to develop two discrete COSs for use in future evaluation of psychosocial interventions aimed at improving outcomes for children and families at risk or with experience of (1) CM or (2) DVA. Methods and analysis A two-phase mixed methods design: (1) rapid reviews of evidence, stakeholder workshops and semistructured interviews with adult survivors of CM/DVA and parents of children who have experienced CM/DVA and (2) a three panel adapted E-Delphi Study and consensus meeting. This study protocol adheres to reporting guidance for COS protocols and has been registered on the Core Outcome Measures for Effectiveness Trials (COMET) database. Ethics and dissemination We will disseminate our findings through peer-reviewed and open access publications, the COMET website and presentations at international conferences. We will engage with research networks, journal editors and funding agencies to promote awareness of the CM-COS and DVA-COS. We will work with advisory and survivor and public involvement groups to coproduce a range of survivor, policy and practice facing outputs. Approval for this study has been granted by the Research Ethics Committee at University College London

    Potential converter for laser-power beaming

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    Future space missions, such as those associated with the Space Exploration Initiative (SEI), will require large amounts of power for operation of bases, rovers, and orbit transfer vehicles. One method for supplying this power is to beam power from a spaced based or Earth based laser power station to a receiver where laser photons can be converted to electricity. Previous research has described such laser power stations orbiting the Moon and beaming power to a receiver on the surface of the Moon by using arrays of diode lasers. Photovoltaic converters that can be efficiently used with these diode lasers are described

    The Self Model and the Conception of Biological Identity in Immunology

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    The self/non-self model, first proposed by F.M. Burnet, has dominated immunology for sixty years now. According to this model, any foreign element will trigger an immune reaction in an organism, whereas endogenous elements will not, in normal circumstances, induce an immune reaction. In this paper we show that the self/non-self model is no longer an appropriate explanation of experimental data in immunology, and that this inadequacy may be rooted in an excessively strong metaphysical conception of biological identity. We suggest that another hypothesis, one based on the notion of continuity, gives a better account of immune phenomena. Finally, we underscore the mapping between this metaphysical deflation from self to continuity in immunology and the philosophical debate between substantialism and empiricism about identity

    Modelling Transmission of Vector-Borne Pathogens Shows Complex Dynamics When Vector Feeding Sites Are Limited

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    The relationship between species richness and the prevalence of vector-borne disease has been widely studied with a range of outcomes. Increasing the number of host species for a pathogen may decrease infection prevalence (dilution effect), increase it (amplification), or have no effect. We derive a general model, and a specific implementation, which show that when the number of vector feeding sites on each host is limiting, the effects on pathogen dynamics of host population size are more complex than previously thought. The model examines vector-borne disease in the presence of different host species that are either competent or incompetent (i.e. that cannot transmit the pathogen to vectors) as reservoirs for the pathogen. With a single host species present, the basic reproduction ratio R0 is a non-monotonic function of the population size of host individuals (H), i.e. a value exists that maximises R0. Surprisingly, if a reduction in host population size may actually increase R0. Extending this model to a two-host species system, incompetent individuals from the second host species can alter the value of which may reverse the effect on pathogen prevalence of host population reduction. We argue that when vector-feeding sites on hosts are limiting, the net effect of increasing host diversity might not be correctly predicted using simple frequency-dependent epidemiological models

    Evolving energy landscapes in the South Wales Valleys: Exploring community perception and participation

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    Emerging and future sustainable energy systems will greatly impact upon landscapes and are likely to require wholesale societal transformation. In Wales, recent policy proposals to achieve decarbonisation prescribe greater roles for local and community energy. However, wider citizen engagement and public discourse on comprehensive energy transformations appear somewhat stagnant. The ‘Stories of Change’ project has sought to catalyse more plural public debates around energy futures. As part of the project, we explored past and present everyday energy relationships with communities in the Valleys of south Wales. At a time of energy transition, and legislative and policy flux, the Valleys afford opportunities to reveal stories about past and present energy experiences and relationships in order to gain enhanced understanding into emerging social meanings of new energy infrastructures and evolving energy landscapes. Here we focus on relationships with ‘old’ energy landscapes; how these and the prevailing socio-economic landscape influence the perceptions and creation of emerging ones; and, how communities are engaged and involved in the making of new energy landscapes. We consider finally how these might inform implementation of proposed energy policy, especially in a Welsh context
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