603 research outputs found

    Bounds on the mass-to-radius ratio for non-compact field configurations

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    It is well known that a spherically symmetric compact star whose energy density decreases monotonically possesses an upper bound on its mass-to-radius ratio, 2M/R8/92M/R\leq 8/9. However, field configurations typically will not be compact. Here we investigate non-compact static configurations whose matter fields have a slow global spatial decay, bounded by a power law behavior. These matter distributions have no sharp boundaries. We derive an upper bound on the fundamental ratio max_r{2m(r)/r} which is valid throughout the bulk. In its simplest form, the bound implies that in any region of spacetime in which the radial pressure increases, or alternatively decreases not faster than some power law r(c+4)r^{-(c+4)}, one has 2m(r)/r(2+2c)/(3+2c)2m(r)/r \leq (2+2c)/(3+2c). [For c0c \leq 0 the bound degenerates to 2m(r)/r2/32m(r)/r \leq 2/3.] In its general version, the bound is expressed in terms of two physical parameters: the spatial decaying rate of the matter fields, and the highest occurring ratio of the trace of the pressure tensor to the local energy density.Comment: 4 page

    Doing research with children and young people who do not use speech for communication

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    Despite emphasis in policy on participation of disabled children, we still know relatively little about how to obtain the views of disabled children with significant communication impairment and their views are often overlooked in planning and service provision. This article describes how the views of children who do not use speech were accessed in research aiming to identify disabled children and young people's priorities regarding outcomes of social care and support services. The main challenge was to develop a method that was reliable, non-threatening, enjoyable and relevant to individual children, as well as enabling children to think beyond their everyday life and express what they aspire to

    Walk well:a randomised controlled trial of a walking intervention for adults with intellectual disabilities: study protocol

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    Background - Walking interventions have been shown to have a positive impact on physical activity (PA) levels, health and wellbeing for adult and older adult populations. There has been very little work carried out to explore the effectiveness of walking interventions for adults with intellectual disabilities. This paper will provide details of the Walk Well intervention, designed for adults with intellectual disabilities, and a randomised controlled trial (RCT) to test its effectiveness. Methods/design - This study will adopt a RCT design, with participants allocated to the walking intervention group or a waiting list control group. The intervention consists of three PA consultations (baseline, six weeks and 12 weeks) and an individualised 12 week walking programme. A range of measures will be completed by participants at baseline, post intervention (three months from baseline) and at follow up (three months post intervention and six months from baseline). All outcome measures will be collected by a researcher who will be blinded to the study groups. The primary outcome will be steps walked per day, measured using accelerometers. Secondary outcome measures will include time spent in PA per day (across various intensity levels), time spent in sedentary behaviour per day, quality of life, self-efficacy and anthropometric measures to monitor weight change. Discussion - Since there are currently no published RCTs of walking interventions for adults with intellectual disabilities, this RCT will examine if a walking intervention can successfully increase PA, health and wellbeing of adults with intellectual disabilities

    An exploration of the use of infant observation methods to research the identities of severely learning disabled adolescents and to enhance relationship-based practice for professional social work practice

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    This paper considers how infant observation methods may be adapted to explore and research the identities of severely learning disabled adolescents, a group of young people whose experiences are poorly represented in the literature. Through focusing on emotion and relationship, this ‘practice-near’ research method also offers a way for social workers to develop their reflective capacity in relation to the often hidden, uncomfortable emotions aroused by experiencing impairment and difference, but without the defences usually involved in assuming the professional role. The importance of taking time to get on a disabled child’s ‘wavelength’ is illustrated through extracts from the research which show how a young person’s agency and identity can be appreciated. The method also has the potential to develop social workers’ awareness of the powerful undercurrent of emotions apparent at times within families of severely disabled young people and tentative suggestions are made about the projective processes and hidden hostilities at work within one of the families observed as part of the research project. Professionals may be able to use this knowledge to become resilient and reflective practitioners and the observation method itself has something to offer by way of a containing experience for families

    Systems biology of platelet-vessel wall interactions

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    Platelets are small, anucleated cells that participate in primary hemostasis by forming a hemostatic plug at the site of a blood vessel's breach, preventing blood loss. However, hemostatic events can lead to excessive thrombosis, resulting in life-threatening strokes, emboli, or infarction. Development of multi-scale models coupling processes at several scales and running predictive model simulations on powerful computer clusters can help interdisciplinary groups of researchers to suggest and test new patient-specific treatment strategies

    Patterns of nucleotide diversity at the regions encompassing the Drosophila insulin-like peptide (dilp) genes: demography vs positive selection in Drosophila melanogaster.

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    In Drosophila, the insulin-signaling pathway controls some life history traits, such as fertility and lifespan, and it is considered to be the main metabolic pathway involved in establishing adult body size. Several observations concerning variation in body size in the Drosophila genus are suggestive of its adaptive character. Genes encoding proteins in this pathway are, therefore, good candidates to have experienced adaptive changes and to reveal the footprint of positive selection. The Drosophila insulin-like peptides (DILPs) are the ligands that trigger the insulin-signaling cascade. In Drosophila melanogaster, there are several peptides that are structurally similar to the single mammalian insulin peptide. The footprint of recent adaptive changes on nucleotide variation can be unveiled through the analysis of polymorphism and divergence. With this aim, we have surveyed nucleotide sequence variation at the dilp1-7 genes in a natural population of D. melanogaster. The comparison of polymorphism in D. melanogaster and divergence from D. simulans at different functional classes of the dilp genes provided no evidence of adaptive protein evolution after the split of the D. melanogaster and D. simulans lineages. However, our survey of polymorphism at the dilp gene regions of D. melanogaster has provided some evidence for the action of positive selection at or near these genes. The regions encompassing the dilp1-4 genes and the dilp6 gene stand out as likely affected by recent adaptive events

    Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

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    A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved

    The social dimension of globalization: A review of the literature

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    With globalization affecting so many inter-connected areas, it is difficult to grasp its full impact. This literature review of over 120 sources considers the impact of globalization on wages and taxes, poverty, inequality, insecurity, child labour, gender, and migration. Opening with some stylized facts concerning globalization in 1985-2002, the authors then highlight recent findings on these areas, reporting on controversies and on emerging consensus where it exists. There follows a review of national and international policy responses designed to make globalization more sustainable and equitable and to deliver decent jobs, security and a voice in decision-making

    Enhancing Crop Gene Pools with Beneficial Traits Using Wild Relatives

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    This review covers genetic resources from wild relatives; barriers and approaches to interspecific gene transfer; beneficial traits from wild relatives that contribute to the gene pool; biotechnological approaches to increase the utilization of wild relatives in crop improvement; and some results of usage of wild relatives in plant breeding

    Biogeography of wild Arachis (Leguminosae): distribution and environmental characterisation.

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    Geographic Information System (GIS) tools are applied to a comprehensive database of 3514 records of wild Arachis species to assist in the conservation and utilisation of the species by: (a) determining the distributional range of species and their abundance; (b) characterising species environments; (c) determining the geographical distribution of species richness; and (d) determining the extent to which species are associated with river basins. Distributional ranges, climatic variables and indices of endemism for each species are tabulated. A. duranensis Krapov. & W.C. Gregory, the most probable donor of the A genome to the cultivated peanut, is distributed in close proximity to both the proposed donor of the B genome, A. ipaënsis, and the closest wild relative of the cultigen, A. monticola Krapov. & Rigoni. This region in the eastern foothills of the Andes and the adjoining chaco regions of Argentina, Bolivia and Paraguay, is a key area for further exploration for wild Arachis. An area of particularly high species richness occurs in the State of Mato Grosso, close to the Gran Pantanal in southwest Brazil. Seventy-one percent of the species were found to have some degree of association with water catchment areas, although in most cases it was difficult to determine whether this was due to climatic adaptation reasons, restricted dispersal due to geocarpic habit, or the role of watercourses as a principal dispersal agent. In only two cases could climatic adaptation be eliminated as the reason for species distribution
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