1,509 research outputs found

    The standstill luminosity in Z Cam systems

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    We consider accretion discs in close binary systems. We show that heating of a disc at the impact point of the accretion stream contributes significantly to the local energy budget at its outer edge. As a result the thermal balance relation between local accretion rate and surface density (the `S-curve') changes; the critical mass transfer rate above which no dwarf nova outbursts occur can be up to 40% smaller than without impact heating. Standstills in ZCam systems thus occur at smaller mass transfer rates than otherwise expected, and are rather fainter than the peak luminosity during the dwarf nova phase as a result.Comment: 3 pages, 3 figures. Accepted for publication in MNRA

    Flexibility and egalitarianism: musical insights from hunter-gatherers

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    Among egalitarian hunter-gatherer groups across the African continent, musical practices and egalitarian socialities are argued to be mutually implicated with one another. Southeast Asian hunter-gatherers also practice egalitarianism, however, and their musical practices represent a seeming anomaly alongside those of many African hunter-gatherer groups. Discussion of ‘hunter-gatherer musics’ that includes Southeast Asian perspectives has therefore been absent, even though cross-cultural, continent-spanning research with hunter-gatherers is common on topics such as politics, economics, and subsistence. Insights into egalitarianism can be gained through attention to the diversity in hunter-gatherer musical practices. This discussion of Ju|'hoan (Namibia) and Batek (Malaysia) musical practices demonstrates that egalitarianism can be understood in terms of its flexibility

    Analysing British sign language through the lens of systemic functional linguistics

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    Approaches to understanding language via Systemic Functional Linguistics (SFL) have resulted in a compendium of literature focussing on language as a ‘social semiotic.’ One such area of this literature comprises systemic functional grammars: descriptions of various languages and the way in which they create meaning. Despite the application of SFL to numerous languages and the creation of systemic functional grammars, a common thread is that of modality: SFL has been applied to numerous languages in the spoken and written modalities, but not in any detail to languages in the visual-spatial modality.My thesis presents an initial attempt at analysing British Sign Language (BSL) through the systemic functional lens. Calling on various theories and methods found in sign linguistics and SFL, I perform an analysis on a sample of BSL clauses (N = 1,375) from three perspectives: how BSL manages exchanges of communication (the interpersonal metafunction); how BSL encodes aspects of experience and reality (the experiential metafunction); and how BSL may be organised to produce a coherent text with variance in information prominence (the textual metafunction). As a result, I present three sets of system networks based on these three metafunctions, complete with realisation statements and examples.This thesis provides considerable impact. From an academic perspective, this is the first in-depth systemic functional description of a language in the visual-spatial modality, providing insight both into how such languages function, and how analyses of these languages may feed back into those of spoken and written languages. From a social perspective, the BSL system networks can assist language learners of any level as a point of reference in clause construction. Furthermore, intermediate and higher BSL qualifications stipulate knowledge of sign linguistics as a required component, yet these assessments are based on resources that have not been updated in nearly twenty years. As such, the products of this thesis may go towards informing future BSL assessments

    Do the UK government's new Quality and Outcomes Framework (QOF) scores adequately measure primary care performance? A cross-sectional survey of routine healthcare data

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    BACKGROUND General practitioners' remuneration is now linked directly to the scores attained in the Quality and Outcomes Framework (QOF). The success of this approach depends in part on designing a robust and clinically meaningful set of indicators. The aim of this study was to assess the extent to which measures of health observed in practice populations are correlated with their QOF scores, after accounting for the established associations between health outcomes and socio-demographics. METHODS QOF data for the period April 2004 to March 2005 were obtained for all general practices in two English Primary Care Trusts. These data were linked to data for emergency hospital admissions (for asthma, cancer, chronic obstructive pulmonary disease, coronary hear disease, diabetes, stroke and all other conditions) and all cause mortality for the period September 2004 to August 2005. Multilevel logistic regression models explored the association between health outcomes (hospital admission and death) and practice QOF scores (clinical, additional services and organisational domains), age, sex and socio-economic deprivation. RESULTS Higher clinical domain scores were generally associated with lower admission rates and this was significant for cancer and other conditions in PCT 2. Higher scores in the additional services domain were associated with higher admission rates, significantly so for asthma, CHD, stroke and other conditions in PCT 1 and cancer in PCT 2. Little association was observed between the organisational domain scores and admissions. The relationship between the QOF variables and mortality was less clear. Being female was associated with fewer admissions for cancer and CHD and lower mortality rates. Increasing age was mainly associated with an increased number of events. Increasing deprivation was associated with higher admission rates for all conditions and with higher mortality rates. CONCLUSION The associations between QOF scores and emergency admissions and mortality were small and inconsistent, whilst the impact of socio-economic deprivation on the outcomes was much stronger. These results have implications for the use of target-based remuneration of general practitioners and emphasise the need to tackle inequalities and improve the health of disadvantaged groups and the population as a whole

    Genome-wide association study of behavioural and psychiatric features in human prion disease.

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    Prion diseases are rare neurodegenerative conditions causing highly variable clinical syndromes, which often include prominent neuropsychiatric symptoms. We have recently carried out a clinical study of behavioural and psychiatric symptoms in a large prospective cohort of patients with prion disease in the United Kingdom, allowing us to operationalise specific behavioural/psychiatric phenotypes as traits in human prion disease. Here, we report exploratory genome-wide association analysis on 170 of these patients and 5200 UK controls, looking for single-nucleotide polymorphisms (SNPs) associated with three behavioural/psychiatric phenotypes in the context of prion disease. We also specifically examined a selection of candidate SNPs that have shown genome-wide association with psychiatric conditions in previously published studies, and the codon 129 polymorphism of the prion protein gene, which is known to modify various aspects of the phenotype of prion disease. No SNPs reached genome-wide significance, and there was no evidence of altered burden of known psychiatric risk alleles in relevant prion cases. SNPs showing suggestive evidence of association (P<10(-5)) included several lying near genes previously implicated in association studies of other psychiatric and neurodegenerative diseases. These include ANK3, SORL1 and a region of chromosome 6p containing several genes implicated in schizophrenia and bipolar disorder. We would encourage others to acquire phenotype data in independent cohorts of patients with prion disease as well as other neurodegenerative and neuropsychiatric conditions, to allow meta-analysis that may shed clearer light on the biological basis of these complex disease manifestations, and the diseases themselves

    The feasibility of thermal and compositional convection in Earth's inner core

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    Inner core convection, and the corresponding variations in grain size and alignment, has been proposed to explain the complex seismic structure of the inner core, including its anisotropy, lateral variations and the F-layer at the base of the outer core. We develop a parametrized convection model to investigate the possibility of convection in the inner core, focusing on the dominance of the plume mode of convection versus the translation mode. We investigate thermal and compositional convection separately so as to study the end-members of the system. In the thermal case the dominant mode of convection is strongly dependent on the viscosity of the inner core, the magnitude of which is poorly constrained. Furthermore recent estimates of a large core thermal conductivity result in stable thermal stratification, hindering convection. However, an unstable density stratification may arise due to the pressure dependant partition coefficient of certain light elements. We show that this unstable stratification leads to compositionally driven convection, and that inner core translation is likely to be the dominant convective mode due to the low compositional diffusivity. The style of convection resulting from a combination of both thermal and compositional effects is not easy to understand. For reasonable parameter estimates, the stabilizing thermal buoyancy is greater than the destabilizing compositional buoyancy. However we anticipate complex double diffusive processes to occur given the very different thermal and compositional diffusivities.We would like to thank Chris Davies for help with comparison to his results, plus Deputy Editor Stephane Labrosse, Renaud Deguen and ´ an anonymous reviewer for constructive comments that improved the manuscript. KHL and AD are funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement number 204995. JAN is partially funded by a Royal Society University Research Fellowship.This is the final published version. This article has been accepted for publication in Geophysical Journal International ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved

    Мовні реалії іншого часу і простору (про особливості слововживання у творах Івана Багряного)

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    The structure of Earthʼs deep inner core has important implications for core evolution, since it is thought to be related to the early stages of core formation. Previous studies have suggested that there exists an innermost inner core with distinct anisotropy relative to the rest of the inner core. Using an extensive new data set of handpicked absolute travel time observations of the inner core phase PKIKP, we find that the data are best explained by variations in anisotropy between two hemispheres and do not require an innermost inner core. We demonstrate that observations of an innermost inner core are an artifact from averaging over lateral anisotropy variations. More significantly we show that hemispherical variations in anisotropy, previously only imaged in the upper inner core, continue to its centre. The eastern region has 0.5–1.5% anisotropy, whereas the western region has 3.5–8.8% anisotropy increasing with depth, with a slow direction at 57–61° to the Earthʼs rotation axis at all depths. Such anisotropy is consistent with models of aligned hcp or bcc iron aggregates

    Imaging and CSF analyses effectively distinguish CJD from its mimics

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    OBJECTIVE: To review clinical and investigation findings in patients referred to a specialist prion clinic who were suspected to have sporadic Creutzfeldt-Jakob disease (sCJD) and yet were found to have an alternative final diagnosis. METHODS: Review the clinical findings and investigations in 214 patients enrolled into the UK National Prion Monitoring Cohort Study between October 2008 and November 2015 who had postmortem confirmed sCJD and compare these features with 50 patients referred over the same period who had an alternative final diagnosis (CJD mimics). RESULTS: Patients with an alternative diagnosis and those with sCJD were of similar age, sex and frequency of dementia but CJD mimics had a longer clinical history. Myoclonus, rigidity and hallucinations were more frequent in patients with sCJD but these features were not helpful in classifying individual patients. Alzheimer's disease, dementia with Lewy bodies and genetic neurodegenerative disorders were alternative diagnoses in more than half of the CJD mimic cases, and 10% had an immune-mediated encephalopathy; lymphoma, hepatic encephalopathy and progressive multifocal leukoencephalopathy were seen more than once. Diffusion-weighted MRI was the most useful readily available test to classify cases correctly (92% CJD, 2% CJD mimics). The CSF cell count, 14-3-3 protein detection and S100B were of limited value. A positive CSF RT-QuIC test, introduced during the course of the study, was found in 89% of tested CJD cases and 0% CJD mimics. CONCLUSION: The combination of diffusion-weighted MRI analysis and CSF RT-QuIC allowed a perfect classification of sCJD versus its mimics in this study
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