390 research outputs found

    The role of density and relatedness in wild juvenile Atlantic salmon growth

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    Growth is a key life-history trait in fish that is influenced by both abiotic (such as temperature and water chemistry) and biotic factors (such as density and food availability). Investigating how growth performance is influenced by such factors in the wild is important for understanding how population processes influence animals in natural environments and for predicting the response to conservation and management strategies that manipulate these conditions. The theory of kin selection predicts that significant growth and survival benefits are conferred upon animals associating with close relatives. However, resource competition may be more intense among close relatives, and little is known about the trade-off between these two processes under different ecological conditions. Here, we examine the correlation between naturally occurring densities and kin-biased growth rate using a species where kin recognition has a strong impact on behaviour in laboratory studies, but where, paradoxically, field investigations have failed to document predicted kin-biased growth or survival. Intra- and inter-family differences in growth rate of juvenile Atlantic salmon Salmo salar were studied to examine how relatedness (groups of full-sibling fish and groups of mixed-sibling fish) and sibling group (family/genotype) affect salmon parr growth, and the correlation of growth rate under a range of naturally occurring densities. Parentage and relatedness of neighbouring fish were assigned using microsatellite and passive integrated transponder tags, which allowed the growth estimation of individual fish. The results show that growth rate was significantly influenced by both sibling group (family of origin) and also by an interaction between relatedness and density. The latter finding indicates that at higher densities, full-sibling groups achieved higher growth rates in comparison to mixed-sibling groups. Thus, the growth benefits of associating with relatives are not conferred under all ecological conditions, but it becomes most apparent at high density when resource competition is greatest

    Microscopic Structure of High-Spin Vibrational Excitations in Superdeformed 190,192,194Hg

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    Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed bands in 190Hg, 192Hg, and 194Hg. The K=2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. At finite frequency, however, the interplay between rotation and vibrations produces different effects depending on neutron number: The lowest octupole phonon is rotationally aligned in 190Hg, is crossed by the aligned two-quasiparticle bands in 192Hg, and retains the K=2 octupole vibrational character up to the highest frequency in 194Hg. The gamma vibrations are predicted to be higher in energy and less collective than the octupole vibrations. From a comparison with the experimental dynamic moments of inertia, a new interpretation of the observed excited bands invoking the K=2 octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in SD Hg nuclei.Comment: 22 pages, REVTeX, 12 postscript figures are available on reques

    Superdeformed rotational bands in the Mercury region; A Cranked Skyrme-Hartree-Fock-Bogoliubov study

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    A study of rotational properties of the ground superdeformed bands in \Hg{0}, \Hg{2}, \Hg{4}, and \Pb{4} is presented. We use the cranked Hartree-Fock-Bogoliubov method with the {\skm} parametrization of the Skyrme force in the particle-hole channel and a seniority interaction in the pairing channel. An approximate particle number projection is performed by means of the Lipkin-Nogami prescription. We analyze the proton and neutron quasiparticle routhians in connection with the present information on about thirty presently observed superdeformed bands in nuclei close neighbours of \Hg{2}.Comment: 26 LaTeX pages, 14 uuencoded postscript figures included, Preprint IPN-TH 93-6

    Risk stratified monitoring for methotrexate toxicity in immune mediated inflammatory diseases: prognostic model development and validation using primary care data from the UK.

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    OBJECTIVE: To develop and validate a prognostic model to inform risk stratified decisions on frequency of monitoring blood tests during long term methotrexate treatment. DESIGN: Retrospective cohort study. SETTING: Electronic health records within the UK's Clinical Practice Research Datalink (CPRD) Gold and CPRD Aurum. PARTICIPANTS: Adults (≥18 years) with a diagnosis of an immune mediated inflammatory disease who were prescribed methotrexate by their general practitioner for six months or more during 2007-19. MAIN OUTCOME MEASURE: Discontinuation of methotrexate owing to abnormal monitoring blood test result. Patients were followed-up from six months after their first prescription for methotrexate in primary care to the earliest of outcome, drug discontinuation for any other reason, leaving the practice, last data collection from the practice, death, five years, or 31 December 2019. Cox regression was performed to develop the risk equation, with bootstrapping used to shrink predictor effects for optimism. Multiple imputation handled missing predictor data. Model performance was assessed in terms of calibration and discrimination. RESULTS: Data from 13 110 (854 events) and 23 999 (1486 events) participants were included in the development and validation cohorts, respectively. 11 candidate predictors (17 parameters) were included. In the development dataset, the optimism adjusted R2 was 0.13 and the optimism adjusted Royston D statistic was 0.79. The calibration slope and Royston D statistic in the validation dataset for the entire follow-up period was 0.94 (95% confidence interval 0.85 to 1.02) and 0.75 (95% confidence interval 0.67 to 0.83), respectively. The prognostic model performed well in predicting outcomes in clinically relevant subgroups defined by age group, type of immune mediated inflammatory disease, and methotrexate dose. CONCLUSION: A prognostic model was developed and validated that uses information collected during routine clinical care and may be used to risk stratify the frequency of monitoring blood test during long term methotrexate treatment

    Excited superdeformed bands in 191Hg

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    Two weakly populated rotational bands have been observed in 191Hg with properties (energy spacings, moments of inertia and lifetimes) very similar to those of the previously reported superdeformed band. Based on cranked Woods-Saxon calculations, these structures are interpreted as the first excited bands in the superdeformed minimum of 191Hg. Comparisons between the data and the calculations highlight the role of specific orbitals at large deformations

    Effect of age, sex and gender on pain sensitivity: A narrative review

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    © 2017 Eltumi And Tashani. Introduction: An increasing body of literature on sex and gender differences in pain sensitivity has been accumulated in recent years. There is also evidence from epidemiological research that painful conditions are more prevalent in older people. The aim of this narrative review is to critically appraise the relevant literature investigating the presence of age and sex differences in clinical and experimental pain conditions. Methods: A scoping search of the literature identifying relevant peer reviewed articles was conducted on May 2016. Information and evidence from the key articles were narratively described and data was quantitatively synthesised to identify gaps of knowledge in the research literature concerning age and sex differences in pain responses. Results: This critical appraisal of the literature suggests that the results of the experimental and clinical studies regarding age and sex differences in pain contain some contradictions as far as age differences in pain are concerned. While data from the clinical studies are more consistent and seem to point towards the fact that chronic pain prevalence increases in the elderly findings from the experimental studies on the other hand were inconsistent, with pain threshold increasing with age in some studies and decreasing with age in others. Conclusion: There is a need for further research using the latest advanced quantitative sensory testing protocols to measure the function of small nerve fibres that are involved in nociception and pain sensitivity across the human life span. Implications: Findings from these studies should feed into and inform evidence emerging from other types of studies (e.g. brain imaging technique and psychometrics) suggesting that pain in the older humans may have unique characteristics that affect how old patients respond to intervention

    The Scientific Foundations of Forecasting Magnetospheric Space Weather

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    The magnetosphere is the lens through which solar space weather phenomena are focused and directed towards the Earth. In particular, the non-linear interaction of the solar wind with the Earth's magnetic field leads to the formation of highly inhomogenous electrical currents in the ionosphere which can ultimately result in damage to and problems with the operation of power distribution networks. Since electric power is the fundamental cornerstone of modern life, the interruption of power is the primary pathway by which space weather has impact on human activity and technology. Consequently, in the context of space weather, it is the ability to predict geomagnetic activity that is of key importance. This is usually stated in terms of geomagnetic storms, but we argue that in fact it is the substorm phenomenon which contains the crucial physics, and therefore prediction of substorm occurrence, severity and duration, either within the context of a longer-lasting geomagnetic storm, but potentially also as an isolated event, is of critical importance. Here we review the physics of the magnetosphere in the frame of space weather forecasting, focusing on recent results, current understanding, and an assessment of probable future developments.Peer reviewe

    Age at first birth in women is genetically associated with increased risk of schizophrenia

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    Prof. Paunio on PGC:n jäsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe

    Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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