1,111 research outputs found

    Experimental and theoretical study of demagnetization fields in superconducting samples of orthorhombic shape

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    In this work we present a model for the calculation of the magnetic properties of superconductors of orthorhombic shape in the perfect shielding state when an external uniform magnetic field is applied in the direction of one of the principal axes of the sample. Our model accounts for demagnetization effects and it is free of fitting parameters and boundary value conditions. We consider planar linear circuits that lie perpendicular to the direction of the applied field. Calculation of the value of the currents is based on magnetic energy minimization. The model is proved to be accurate enough to reproduce experimental results as long as the dimension along the applied field is not much lower than the other dimensions. Calculations of surface currents, as well as measurements and calculations of magnetization and initial susceptibility, are reported. We also present an empirical formula that provides a good fit to the initial susceptibility of a general sample of orthorhombic shape. Demagnetization effects observed on the experimental results are explained in terms of the induced currents in the superconductor. (C) 2004 American Institute of Physics.96148649

    Central and peripheral GLP-1 systems independently suppress eating

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    The anorexigenic peptide glucagon-like peptide-1 (GLP-1) is secreted from gut enteroendocrine cells and brain preproglucagon (PPG) neurons, which, respectively, define the peripheral and central GLP-1 systems. PPG neurons in the nucleus tractus solitarii (NTS) are widely assumed to link the peripheral and central GLP-1 systems in a unified gut–brain satiation circuit. However, direct evidence for this hypothesis is lacking, and the necessary circuitry remains to be demonstrated. Here we show that PPGNTS neurons encode satiation in mice, consistent with vagal signalling of gastrointestinal distension. However, PPGNTS neurons predominantly receive vagal input from oxytocin-receptor-expressing vagal neurons, rather than those expressing GLP-1 receptors. PPGNTS neurons are not necessary for eating suppression by GLP-1 receptor agonists, and concurrent PPGNTS neuron activation suppresses eating more potently than semaglutide alone. We conclude that central and peripheral GLP-1 systems suppress eating via independent gut–brain circuits, providing a rationale for pharmacological activation of PPGNTS neurons in combination with GLP-1 receptor agonists as an obesity treatment strategy

    Structural and magnetic study of LaBaCoCuO5+delta

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    The structure and magnetic properties of the compound LaBaCuCoO5+delta have been studied for the non-stoichiometric oxygen concentration delta approximate to 0.6. The structure is pseudo-cubic with a tripled perovskite unit cell. The crystal structure was determined by a combined Rietveld fit to neutron and synchrotron x-ray powder diffraction data in the orthorhombic Pmmm space group, with cell parameters a=3.9223(3) angstrom, b=3.9360(3) angstrom, c=11.7073(8) angstrom, and V=180.74(2) angstrom(3) (room temperature). Antiferromagnetic ordering of Cu and Co magnetic moments is observed below 205(4) K. The magnetic structure with cell a(M)=2a, b(M)=2b, and c(M)=2c, could be described with the Shubnikov space group Fmmm'. The magnetic moments of both equivalent Cu/Co sites were determined at 50 and 170 K to be 0.83(3)mu(B) and 0.58(3)mu(B), respectively, consistent with one unpaired electron per atom. The fit of the intensities to a simple mean field magnetic model appeared to be insufficient to account for the variation of moments at temperatures close to T-N while a three dimensional Heisenberg model could improve the fit. Susceptibility measurements between 4 and 350 K also show irreversibility below 150 K. The local environments of Cu and Co were studied by extended x-ray absorption fine structure spectroscopy at both absorption edges. Cu atoms adopt an elongated octahedral or square-based pyramidal oxygen environment which suggests mainly the presence of Cu(II) in the structure. Co adopts different local environments, depending on the electronic and spin states.711

    Reproducibility of fetal heart volume by 3D-sonography using the XI VOCAL method

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    <p>Abstract</p> <p>Background</p> <p>To assess the reliability of fetal heart volume measurement by three-dimensional sonography (3DUS) using the eXtended Imaging Virtual Organ Computer-aided AnaLysis (XI VOCAL) method.</p> <p>Methods</p> <p>This reliability study enrolled 30 pregnant women with singleton healthy pregnancies between 19 and 34 weeks of gestation. All volume acquirements were performed with a convex volumetric transducer (C3-7ED) coupled to an Accuvix XQ sonography device (Medison, Korea). The XI VOCAL 10 planes was the method of choice for volumetric measurement. 3D datasets were analyzed by two observers (EQSB and HJFM); fetal heart volume was measured twice by the first and once by the second observer to calculate intra and interobserver reproducibility. Statistical analysis used pareated Student's t test (p) and calculated Intraclass correlation coefficients (ICC). Bland-Altman plots were also constructed.</p> <p>Results</p> <p>We observed an excellent intra- and interobserver reliability for fetal cardiac volume assessed by XI VOCAL. For the intraobserver the ICC was 0.998 (95% CI: 0.997; 0.999), with mean of differences of 0.12 cm<sup>3 </sup>(95% limits of agreement: -0.84; +0.84; p = 0.130). For interobserver the ICC was 0.899 (95%CI: 0.996; 0.998), mean of differences 0.05 cm<sup>3 </sup>(95% limits of agreement: -0.84; +0.84; p = 0.175).</p> <p>Conclusion</p> <p>Fetal cardiac volume assessed by 3DUS using XI VOCAL method is highly reproducible between 19 to 34 gestational weeks.</p

    Climate Change, Habitat Loss, Protected Areas and the Climate Adaptation Potential of Species in Mediterranean Ecosystems Worldwide

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    Mediterranean climate is found on five continents and supports five global biodiversity hotspots. Based on combined downscaled results from 23 atmosphere-ocean general circulation models (AOGCMs) for three emissions scenarios, we determined the projected spatial shifts in the mediterranean climate extent (MCE) over the next century. Although most AOGCMs project a moderate expansion in the global MCE, regional impacts are large and uneven. The median AOGCM simulation output for the three emissions scenarios project the MCE at the end of the 21st century in Chile will range from 129–153% of its current size, while in Australia, it will contract to only 77–49% of its current size losing an area equivalent to over twice the size of Portugal. Only 4% of the land area within the current MCE worldwide is in protected status (compared to a global average of 12% for all biome types), and, depending on the emissions scenario, only 50–60% of these protected areas are likely to be in the future MCE. To exacerbate the climate impact, nearly one third (29–31%) of the land where the MCE is projected to remain stable has already been converted to human use, limiting the size of the potential climate refuges and diminishing the adaptation potential of native biota. High conversion and low protection in projected stable areas make Australia the highest priority region for investment in climate-adaptation strategies to reduce the threat of climate change to the rich biodiversity of the mediterranean biome

    Burden and modifications in life from the perspective of caregivers for patients after stroke

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    OBJECTIVE: to analyze the impact that caring has on a member of the family caring for a patient after a cerebrovascular accident, correlating life modifications and mental suffering with the perceived burden. METHOD: a cross-sectional, quantitative study, undertaken in January-April 2010 in Fortaleza, Ceará, Brazil. RESULT: 61 individuals were investigated, monitored by three hospitals' Home Care Program. Data collection was through interviews for identifying life changes, and through the application of three scales for investigating perceived burden, mental state and mental suffering. Respectively these were the Caregiver Burden Scale (CBS), the Mini-Mental State Examination (MMSE) and the Self Reported Questionnaire (SRQ). The majority of the carers were female, married, and the children of the stroke patients. The average age was 48.2 years (±12.4). The most-cited life modifications referred to the daily routine, to leisure activities, and to exhaustion or tiredness. Regarding burden, the dimensions of General tension, Isolation and Disappointment stood out. It was ascertained that overload was more severe when the carer presented more symptoms of psychological distress, in the absence of a secondary carer, and when the principal carers reported perceiving changes in their bodies and health. CONCLUSION: an association between burden and the carer's mental state was not observed. Understanding the care, through analysis of the burden and of the knowledge of the biopsychosocial situation will provide support for the nurse's work in reducing the overload for family caregivers.OBJETIVO: analizar el impacto del cuidar para el cuidador familiar de paciente después de accidente vascular cerebral, correlacionando modificaciones de vida y sufrimiento psíquico con la sobrecarga percibida. MÉTODO: estudio transversal, cuantitativo, realizado de enero a abril de 2010, en Fortaleza, Ceará, Brasil. RESULTADO: se investigaron 61 individuos, acompañados por el Programa de Servicio Domiciliar de tres hospitales. La colecta de los datos ocurrió mediante entrevista para identificar modificaciones de vida, y con la aplicación de tres escalas para investigar la sobrecarga percibida, estado mental y sufrimiento psíquico. Son ellas, respectivamente: Caregiver Burden Scale (CBS), Mini Examen del Estado Mental (MEEM) y Self Reported Questionnaire (SRQ). Los cuidadores, en su mayoría, eran del sexo femenino, casados (as) e hijo (as) de los pacientes después del AVC. Edad Media de 48,2 años (±12,4). Las modificaciones de vida más citadas fueron referentes a la rutina diaria, a las actividades de ocio y agotamiento o cansancio. En cuanto a la sobrecarga, se destacaron las dimensiones Tensión general, Aislamiento y Decepción. Se verificó mayor sobrecarga cuanto más síntomas de sufrimiento psíquico el cuidador presentase, en la ausencia de cuidador secundario y cuando los cuidadores principales relataron percibir modificación en el cuerpo y en la salud. CONCLUSIÓN: no fue observada asociación de la sobrecarga con el estado mental del cuidador. Entender la coyuntura del cuidado, mediante análisis del recargo de trabajo, y del conocimiento de la situación biopsicosocial, suministrará subsidios para la actuación del enfermero para reducir la carga generada para los cuidadores familiares.OBJETIVO: analisar o impacto do cuidar para o cuidador familiar de paciente após acidente vascular cerebral (AVC), correlacionando modificações de vida e sofrimento psíquico com a sobrecarga percebida. MÉTODO: estudo transversal, quantitativo, realizado de janeiro a abril de 2010, em Fortaleza, Ceará, Brasil. RESULTADO: investigaram-se 61 indivíduos, acompanhados pelo Programa de Atendimento Domiciliar (PAD), de três hospitais. A coleta dos dados ocorreu mediante entrevista para identificar modificações de vida, e com a aplicação de três escalas para investigar sobrecarga percebida, estado mental e sofrimento psíquico. São elas, respectivamente: Caregiver Burden Scale (CBS), Miniexame do Estado Mental (MEEM) e Self Reported Questionnaire (SRQ). Os cuidadores, na sua maioria, eram do sexo feminino, casados(as) e filho(as) dos pacientes após AVC. A média de idade era de 48,2 anos (±12,4). As modificações de vida mais citadas foram referentes à rotina diária, às atividades de lazer e esgotamento ou cansaço. Quanto à sobrecarga, destacaram-se as dimensões tensão geral, isolamento e decepção. Verificou-se maior sobrecarga quanto mais sintomas de sofrimento psíquico o cuidador apresentasse, na ausência de cuidador secundário e quando os cuidadores principais relataram perceber modificação no corpo e na saúde. CONCLUSÃO: não foi observada associação da sobrecarga com o estado mental do cuidador. Entender a conjuntura do cuidado, mediante análise da sobrecarga de trabalho, e do conhecimento da situação biopsicossocial fornecerá subsídios para a atuação do enfermeiro para reduzir a carga gerada para os cuidadores familiares

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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