1,018 research outputs found

    Genetic influence on East African running success

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    East African athletes now dominate international distance running events from the 800 m to the marathon. Explanations for their phenomenal success have included optimal environmental conditions for developing distance running performance, psychological advantage and advantageous physiological characteristics. It is well established that genetics plays a role in determining inter-individual differences in exercise performance and adaptation to training stimuli. It is not known, however, to what extent inter-population differences (i.e. between ‘races’ and/or ethnic groups) in exercise performance can be attributed to genetics. There have been considerations that ‘black’ athletes are genetically adapted towards performance, given the concurrent success of athletes of West African ancestry in sprint events. However, the current notion of ‘race’ is not universally accepted, and genetic differences within and between populations are not clearly delineated by geographical or ethnic categorizations. Recent findings from mitochondrial DNA show that the populations from which Ethiopian athletes are drawn have not been isolated populations and are not genetically distinct from other Ethiopians. Y-chromosome analysis of the same population shows concurrent results, although some differences are present between athletes and the general Ethiopian population, suggesting an influence of the Y chromosome on athlete status in Ethiopia. It is concluded that there may be a role for genetics in the success of East African athletes; however, any genetic component to their success is unlikely to be limited to East Africans and is more likely to be found in other populations. At present it is unjustified to implicate a role for genetics in the success of East African runners when no genes have been identified as being important to their performance

    A record of Neogene seawater δ11B reconstructed from paired δ11B analyses on benthic and planktic foraminifera

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    The work was supported by NERC grants NE/I006176/1 (Gavin L. Foster and Caroline H. Lear), NE/H006273/1 (Gavin L. Foster), NE/I006168/1 and NE/K014137/1 and a Royal Society Research Merit Award (Paul A. Wilson), a NERC Independent Research Fellowship NE/K00901X/1 (Mathis P. Hain) and a NERC studentship (Rosanna Greenop).The boron isotope composition (δ11B) of foraminiferal calcite reflects the pH and the boron isotope composition of the seawater the foraminifer grew in. For pH reconstructions, the δ11B of seawater must therefore be known, but information on this parameter is limited. Here we reconstruct Neogene seawater δ11B based on the δ11B difference between paired measurements of planktic and benthic foraminifera and an estimate of the coeval water column pH gradient from their δ13C values. Carbon cycle model simulations underscore that the ΔpH-Δδ13C relationship is relatively insensitive to ocean and carbon cycle changes, validating our approach. Our reconstructions suggest that δ11Bsw was ∼37.5‰ during the early and middle Miocene (roughly 23-12 Ma) and rapidly increased during the late Miocene (between 12 and 5 Ma) towards the modern value of 39.61 ‰. Strikingly, this pattern is similar to the evolution of the seawater isotope composition of Mg, Li and Ca, suggesting a common forcing mechanism. Based on the observed direction of change, we hypothesize that an increase in secondary mineral formation during continental weathering affected the isotope composition of riverine input to the ocean since 14 Ma.Publisher PDFPeer reviewe

    Grounding knowledge and normative valuation in agent-based action and scientific commitment

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    Philosophical investigation in synthetic biology has focused on the knowledge-seeking questions pursued, the kind of engineering techniques used, and on the ethical impact of the products produced. However, little work has been done to investigate the processes by which these epistemological, metaphysical, and ethical forms of inquiry arise in the course of synthetic biology research. An attempt at this work relying on a particular area of synthetic biology will be the aim of this chapter. I focus on the reengineering of metabolic pathways through the manipulation and construction of small DNA-based devices and systems synthetic biology. Rather than focusing on the engineered products or ethical principles that result, I will investigate the processes by which these arise. As such, the attention will be directed to the activities of practitioners, their manipulation of tools, and the use they make of techniques to construct new metabolic devices. Using a science-in-practice approach, I investigate problems at the intersection of science, philosophy of science, and sociology of science. I consider how practitioners within this area of synthetic biology reconfigure biological understanding and ethical categories through active modelling and manipulation of known functional parts, biological pathways for use in the design of microbial machines to solve problems in medicine, technology, and the environment. We might describe this kind of problem-solving as relying on what Helen Longino referred to as “social cognition” or the type of scientific work done within what Hasok Chang calls “systems of practice”. My aim in this chapter will be to investigate the relationship that holds between systems of practice within metabolic engineering research and social cognition. I will attempt to show how knowledge and normative valuation are generated from this particular network of practitioners. In doing so, I suggest that the social nature of scientific inquiry is ineliminable to both knowledge acquisition and ethical evaluations

    Association between critical care admission and 6-month functional outcome after spontaneous intracerebral haemorrhage

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    BACKGROUND: There is uncertainty about the clinical benefit of admission to critical care after spontaneous intracerebral haemorrhage (ICH). PURPOSE: We investigated factors associated with critical care admission after spontaneous ICH and evaluated associations between critical care and 6-month functional outcome. METHODS: We included 825 patients with acute spontaneous non-traumatic ICH, recruited to a prospective multicenter observational study. We evaluated the characteristics associated with critical care admission and poor 6-month functional outcome (modified Rankin Scale, mRS > 3) using univariable (chi-square test and Wilcoxon rank-sum test, as appropriate) and multivariable analysis. RESULTS: 286 patients (38.2%) had poor 6-month functional outcome. Seventy-seven (9.3%) patients were admitted to critical care. Patients admitted to critical care were younger (p < 0.001), had lower GCS score (p < 0.001), larger ICH volume (p < 0.001), more often had intraventricular extension (p = 0.008) and underwent neurosurgery (p < 0.001). Critical care admission was associated with poor functional outcome at 6 months (39/77 [50.7%] vs 286/748 [38.2%]; p = 0.034); adjusted OR 2.43 [95%CI 1.36-4.35], p = 0.003), but not with death (OR 1.29 [95%CI 0.71-2.35; p = 0.4). In ordinal logistic regression, patients admitted to critical care showed an OR 1.47 (95% CI 0.98-2.20; p = 0.07) for a shift in the 6-month modified Rankin Scale. CONCLUSIONS: Admission to critical care is associated with poor 6-month functional outcome after spontaneous ICH but not with death. Patients admitted to critical care were a priori more severely affected. Although adjusted for main known predictors of poor outcome, our findings could still be confounded by unmeasured factors. Establishing the true effectiveness of critical care after ICH requires a randomised trial with clinical outcomes and quality of life assessments

    Neutrino Interactions in Hot and Dense Matter

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    We study the charged and neutral current weak interaction rates relevant for the determination of neutrino opacities in dense matter found in supernovae and neutron stars. We establish an efficient formalism for calculating differential cross sections and mean free paths for interacting, asymmetric nuclear matter at arbitrary degeneracy. The formalism is valid for both charged and neutral current reactions. Strong interaction corrections are incorporated through the in-medium single particle energies at the relevant density and temperature. The effects of strong interactions on the weak interaction rates are investigated using both potential and effective field-theoretical models of matter. We investigate the relative importance of charged and neutral currents for different astrophysical situations, and also examine the influence of strangeness-bearing hyperons. Our findings show that the mean free paths are significantly altered by the effects of strong interactions and the multi-component nature of dense matter. The opacities are then discussed in the context of the evolution of the core of a protoneutron star.Comment: 41 pages, 25 figure

    Relative energetics and structural properties of zirconia using a self-consistent tight-binding model

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    We describe an empirical, self-consistent, orthogonal tight-binding model for zirconia, which allows for the polarizability of the anions at dipole and quadrupole levels and for crystal field splitting of the cation d orbitals. This is achieved by mixing the orbitals of different symmetry on a site with coupling coefficients driven by the Coulomb potentials up to octapole level. The additional forces on atoms due to the self-consistency and polarizabilities are exactly obtained by straightforward electrostatics, by analogy with the Hellmann-Feynman theorem as applied in first-principles calculations. The model correctly orders the zero temperature energies of all zirconia polymorphs. The Zr-O matrix elements of the Hamiltonian, which measure covalency, make a greater contribution than the polarizability to the energy differences between phases. Results for elastic constants of the cubic and tetragonal phases and phonon frequencies of the cubic phase are also presented and compared with some experimental data and first-principles calculations. We suggest that the model will be useful for studying finite temperature effects by means of molecular dynamics.Comment: to be published in Physical Review B (1 march 2000

    A HST/WFPC2 survey of bright young clusters in M31. I. VdB0, a massive star cluster seen at ~= 25 Myr

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    {Aims.} We introduce our imaging survey of possible young massive globular clusters in M31 performed with the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST). We present here details of the data reduction pipeline that is being applied to all the survey data and describe its application to the brightest among our targets, van den Bergh 0 (VdB0), taken as a test case. {Methods.} The reddening, the age and the metallicity of the cluster are estimated by comparison of the observed Color Magnitude Diagram (CMD) with theoretical isochrones. {Results.} Under the most conservative assumptions the stellar mass of VdB0 is M > 2.4 x 10^4 M_sun, but our best estimates lie in the range ~ 4-9 x 10^4 M_sun. The CMD of VdB0 is best reproduced by models having solar metallicity and age = 25 Myr. Ages smaller than = 12 Myr and larger than = 60 Myr are clearly ruled out by the available data. The cluster has a remarkable number of Red Super Giants (> 18) and a CMD very similar to Large Magellanic Cloud clusters usually classified as young globulars such as NGC 1850, for example. {Conclusions.} VdB0 is significantly brighter (>~ 1 mag) than Galactic open clusters of similar age. Its present-day mass and half-light radius (r_h=7.4 pc) are more typical of faint globular clusters than of open clusters. However, given its position within the disk of M31 it is expected to be destroyed by dynamical effects, in particular by encounters with giant molecular clouds, within the next ~ 4 Gyr.Comment: 18 pages, 16 figures (quality of Figures 1,2,3 and 4 reduced). Accepted for publication in Astronomy & Astrophysics. Minor revisions to sect. 1.

    Ecology of domestic dogs (Canis familiaris) as a host for Guinea worm (Dracunculus medinensis) infection in Ethiopia

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    This is the final version. Available on open access from Wiley via the DOI in this recordThe global programme for the eradication of Guinea worm disease, caused by the parasitic nematode Dracunculus medinensis, has been successful in driving down human cases, but infections in non-human animals, particularly domestic dogs (Canis familiaris), now present a major obstacle to further progress. Dog infections have mainly been found in Chad and, to a lesser extent, in Mali and Ethiopia. While humans classically acquire infection by drinking water containing infected copepods, it has been hypothesized that dogs might additionally or alternatively acquire infection via a novel pathway, such as consumption of fish or frogs as possible transport or paratenic hosts. We characterized the ecology of free-ranging dogs living in three villages in Gog woreda, Gambella region, Ethiopia, in April–May 2018. We analysed their exposure to potential sources of Guinea worm infection and investigated risk factors associated with infection histories. The home ranges of 125 dogs and their activity around water sources were described using GPS tracking, and the diets of 119 dogs were described using stable isotope analysis. Unlike in Chad, where Guinea worm infection is most frequent, we found no ecological or behavioural correlates of infection history in dogs in Ethiopia. Unlike in Chad, there was no effect of variation among dogs in their consumption of aquatic vertebrates (fish or frogs) on their infection history, and we found no evidence to support hypotheses for this novel transmission pathway in Ethiopia. Dog owners had apparently increased the frequency of clean water provision to dogs in response to previous infections. Variations in dog ranging behaviour, owner behaviour and the characteristics of natural water bodies all influenced the exposure of dogs to potential sources of infection. This initial study suggests that the classical transmission pathway should be a focus of attention for Guinea worm control in non-human animals in Ethiopia.Carter Cente

    Understanding, treating, and renaming grandiose delusions : a qualitative study

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    Background Grandiose delusions are arguably the most neglected psychotic experience in research. Objectives We aimed to discover from patients: whether grandiose delusions have harmful consequences; the psychological mechanisms that maintain them; and what help patients may want from clinical services. Design A qualitative interview design was used to explore patients’ experiences of grandiose delusions. Method Fifteen patients with past or present experiences of grandiose delusions who were attending psychiatric services were interviewed. Thematic analysis and grounded theory were used to analyse the data. Results Participants reported physical, sexual, social, occupational, and emotional harms from grandiose delusions. All patients described the grandiose belief as highly meaningful: it provided a sense of purpose, belonging, or self‐identity, or it made sense of unusual or difficult events. The meaning from the belief was not synonymous with extreme superiority or arrogance. The meaning obtained appeared to be a key driver of the persistence of the beliefs. Other maintenance factors were subjectively anomalous experiences (e.g., voices), symptoms of mania, fantasy elaboration, reasoning biases, and immersive behaviours. Participants described insufficient opportunities to talk about their grandiose beliefs and related experiences and were generally positive about the possibility of a psychological therapy. Conclusions We conclude that grandiosity is a psychologically rich experience, with a number of maintenance factors that may be amenable to a targeted psychological intervention. Importantly, the term ‘grandiose delusion’ is an imprecise description of the experience; we suggest ‘delusions of exceptionality’ may be a credible alternative. Practitioner points -Harm from grandiose delusions can occur across multiple domains (including physical, sexual, social, occupational, and emotional) and practitioners should assess accordingly. -However, grandiose delusions are experienced by patients as highly meaningful: they provide a sense of purpose, belonging, or self‐identity, or make sense of unusual or difficult events. -Possible psychological maintenance mechanisms that could be a target for intervention include the meaning of the belief, anomalous experiences, mania, fantasy elaboration, reasoning biases, and immersive behaviours. -Patients are keen to have the opportunity to access talking therapies for this experience. Taking extra time to talk at times of distress, ‘going the extra mile’, and listening carefully can help to facilitate trust
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