1,812 research outputs found

    Risk, Harm and Intervention: the case of child obesity

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    In this paper we aim to demonstrate the enormous ethical complexity that is prevalent in child obesity cases. This complexity, we argue, favors a cautious approach. Against those perhaps inclined to blame neglectful parents, we argue that laying the blame for child obesity at the feet of parents is simplistic once the broader context is taken into account. We also show that parents not only enjoy important relational prerogatives worth defending, but that children, too, are beneficiaries of that relationship in ways difficult to match elsewhere. Finally, against the backdrop of growing public concern and pressure to intervene earlier in the life cycle, we examine the perhaps unintended stigmatizing effects that labeling and intervention can have and consider a number of risks and potential harms occasioned by state interventions in these cases

    A finite element approach for vector- and tensor-valued surface PDEs

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    We derive a Cartesian componentwise description of the covariant derivative of tangential tensor fields of any degree on general manifolds. This allows to reformulate any vector- and tensor-valued surface PDE in a form suitable to be solved by established tools for scalar-valued surface PDEs. We consider piecewise linear Lagrange surface finite elements on triangulated surfaces and validate the approach by a vector- and a tensor-valued surface Helmholtz problem on an ellipsoid. We experimentally show optimal (linear) order of convergence for these problems. The full functionality is demonstrated by solving a surface Landau-de Gennes problem on the Stanford bunny. All tools required to apply this approach to other vector- and tensor-valued surface PDEs are provided

    Coulomb gauge studies of SU(3) Yang-Mills theory on the lattice

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    We study the infrared behaviour of lattice SU(3) Yang-Mills theory in Coulomb gauge in terms of the ghost propagator, the Coulomb potential and the transversal and the time-time component of the equal-time gluon propagator. In particular, we focus on the Gribov problem and its impact on the observables. We observe that the simulated annealing method is advantageous for fixing the Coulomb gauge in large volumes. We study finite size and discretization effects. While finite size effects can be controlled by the cone cut, and the ghost propagator and the Coulomb potential become scaling functions with the cylinder cut, the equal-time gluon propagator does not show scaling in the considered range of the inverse coupling constant. The ghost propagator is infrared enhanced. The Coulomb potential is now extended to considerably lower momenta and shows a more complicated infrared regime. The Coulomb string tension satisfies Zwanziger's inequality, but its estimate can be considered only preliminary because of the systematic Gribov effect that is particularly strong for the Coulomb potential.Comment: 7 pages, 5 pictures, poster presented at the XXV International Symposium on Lattice Field Theory, July 30 - August 4 2007, Regensburg, Germany; corrected value for fitting parameter

    The diagnostic value of adenosine deaminase activity in the ascitic fluid of patients with tuberculous peritonitis

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    This study was designed to: 1. Examine the diagnostic value of ADA levels in ascitic fluid, 2. Establish the sensitivity and specificity of this test in the diagnosis of tuberculous peritonitis, in a large number of patients, 3. Establish levels of adenosine deaminase activity which give the best discriminatory information in patients with ascites. 4. Determine what conditions may give rise to false positive or false negative results. 5. Finally, the study was designed to assess the relative diagnostic accuracy of previously used biochemical and haematological data, such as ascites total protein and white cell count. The diagnostic value of these tests alone, and combined with ADA activity in a descriminant analysis, was compared with the diagnostic accuracy of adenosine deaminase activity alone

    Nematic liquid crystals on curved surfaces - a thin film limit

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    We consider a thin film limit of a Landau-de Gennes Q-tensor model. In the limiting process we observe a continuous transition where the normal and tangential parts of the Q-tensor decouple and various intrinsic and extrinsic contributions emerge. Main properties of the thin film model, like uniaxiality and parameter phase space, are preserved in the limiting process. For the derived surface Landau-de Gennes model, we consider an L2-gradient flow. The resulting tensor-valued surface partial differential equation is numerically solved to demonstrate realizations of the tight coupling of elastic and bulk free energy with geometric properties.Comment: 20 pages, 4 figure

    What drives changes in carbon emissions? : an index decomposition approach for 40 countries

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    This study analyzes carbon emission trends and drivers in 40 major economies using the WIOD database, a harmonized and consistent dataset of input-output table time series accompanied by environmental satellite data. We use logarithmic mean Divisia index decomposition to (1) study trends in global carbon emissions between 1995 and 2009, (2) attribute changes in carbon emissions to either influences of economic activity, changes in technology, changes in the structure of the economy, alterations of the fuel mix, or changes in carbon intensities of specific fuel types, and (3) highlight sectoral and regional differences. We first find that heterogeneity in each country is higher than heterogeneity in sectors. This finding might lead to the conclusion that, in order to abate CO2, structural conditions in sectors prevail over regional circumstances. Regarding our results of the decomposition analysis, the drivers of changes in carbon emissions are very heterogeneous. Among the world’s top ten emitters, in only three countries – China, Germany and Canada – the main driver of an improved emissions performance was technological change. Conversely, in Japan and Australia structural change of the economy contributed to less severe increases of emissions. The deployment of cleaner energy sources had a positive in some, mainly developed, economies. Moreover, our results for the global level suggest a general move towards more efficient means of production

    Hepatitis C - a South African perspective

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    The existence of non-A, non-B (NANB) hepatitis was established in the 1970s, when accurate serological tests allowed exclusion of hepatitis A and B viruses as the cause of most cases of post-transfusion hepatitis. The term 'hepatitis C' was coined after molecular cloning of nucleic acid from highly infectious sera of chimpanzees identified an RNA virus as the primary cause of post-transfusion hepatitis (PTH). Sequence analysis and expression of the RNA has shown it to be closely related to the flavi- and pestiviruses. It has marked genomic variability which may affect its biological and immunological characteristics, is transmitted parenterally and sporadically, by as yet unidentified routes, and causes chronic indolent liver disease in 50 - 75% of infected patients. It is associated with hepatocellular carcinoma, glomerulonephritis, cryoglobulinaemia, auto-immune liver disease, lymphocytic sialadenitis and porphyria cutanea tarda. Up to 500 million people worldwide may be infected with hepatitis C virus (HCV), and many questions about the disease remain unanswered. Therapy is still largely ineffective and our current understanding of the long-term natural history, our methods of diagnosis, therapy, prevention and immunisation are suboptimal

    Foreword

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    Early Middle Cambrian bituminous coquinoid limestones from a tectonically isolated outcrop in southwestern Kyrgyzstan yield a remarkably diverse fauna, with stem-group cnidarians, trilobites, rhynchonelliformean brachiopods, and other shelly fossils. The fossil site is in the northern foothills of the Turkestan Range and thus forms part of the westernmost extension of the South Tien Shan. The fauna includes two fairly well known trilobite species, Glabrella ventrosa Lermontova, 1940 and Dorypyge richthofeniformis Lermontova, 1940, that provide confident support for an Amgan age of the rocks. New described taxa include the stem-group cnidarian Cambroctoconus kyrgyzstanicus Peel sp. nov., the trilobite Olenoides sagittatus Geyer sp. nov., and the helcionelloid Manasoconus bifrons Peel gen. et sp. nov. Additional fossils within the samples include the trilobites Olenoides sp. A, Kootenia sp., and Pseudoeteraspis? sp.; the rhynchonelliform brachiopods Narynella cf. ferganensis (Andreeva, 1962), Narynella? sp., Austrohedra? sp. nov., and two species of uncertain generic affinity; the tommotiid Tesella sp.; the hyolithelminth Hyolithellus sp.; and the palaeoscolecid Hadimopanella oezgueli Gedik, 1977. Of particular interest is Cambroctoconus kyrgyzstanicus with an octagonal corallum and a sparsely septate calyx

    S\'{e}rsic galaxy models in weak lensing shape measurement: model bias, noise bias and their interaction

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    Cosmic shear is a powerful probe of cosmological parameters, but its potential can be fully utilised only if galaxy shapes are measured with great accuracy. Two major effects have been identified which are likely to account for most of the bias for maximum likelihood methods in recent shear measurement challenges. Model bias occurs when the true galaxy shape is not well represented by the fitted model. Noise bias occurs due to the non-linear relationship between image pixels and galaxy shape. In this paper we investigate the potential interplay between these two effects when an imperfect model is used in the presence of high noise. We present analytical expressions for this bias, which depends on the residual difference between the model and real data. They can lead to biases not accounted for in previous calibration schemes. By measuring the model bias, noise bias and their interaction, we provide a complete statistical framework for measuring galaxy shapes with model fitting methods from GRavitational lEnsing Accuracy Testing (GREAT) like images. We demonstrate the noise and model interaction bias using a simple toy model, which indicates that this effect can potentially be significant. Using real galaxy images from the Cosmological Evolution Survey (COSMOS) we quantify the strength of the model bias, noise bias and their interaction. We find that the interaction term is often a similar size to the model bias term, and is smaller than the requirements of the current and shortly upcoming galaxy surveys.Comment: 11 pages, 3 figure
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