2,580 research outputs found

    Negative modes and the thermodynamics of Reissner-Nordstr\"om black holes

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    We analyse the problem of negative modes of the Euclidean section of the Reissner-Nordstr\"om black hole in four dimensions. We find analytically that a negative mode disappears when the specific heat at constant charge becomes positive. The sector of perturbations analysed here is included in the canonical partition function of the magnetically charged black hole. The result obeys the usual rule that the partition function is only well-defined when there is local thermodynamical equilibrium. We point out the difficulty in quantising Einstein-Maxwell theory, where the so-called conformal factor problem is considerably more intricate. Our method, inspired by hep-th/0608001, allows us to decouple the divergent gauge volume and treat the metric perturbations sector in a gauge-invariant way.Comment: 24 pages, 1 figure; v2 minor changes to fit published versio

    Estado Confusional Agudo após Corticoterapia Inalada

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    Background: The connection between corticotherapy and neuropsychiatric symptoms is widely known, being one of the first questions we need to assess when presenting with first episode psychiatric symptoms or confusional state. Aims: To date, data on cases related to inhaled corticotherapy and neuropsychiatric effects is scarce. In this paper we describe a rare case in a young woman. Methods: The clinical case presented led us to try to understand the data published on the subject in order to discuss it in greater length. Results and Conclusions: We present and discuss a 27-year-old patient’s case, with no previous psychiatric disease, who was admitted to our Psychiatric ward after the onset of severe acute behavioural disturbance characterized by aggressiveness, visual and auditory hallucinatory activity, misidentification and altered conscience status. It was later found that seven days earlier she had been prescribed inhaled corticotherapy for a minor respiratory infection. A few days after corticotherapy withdrawal, the clinical symptoms improved significantly.info:eu-repo/semantics/publishedVersio

    Instability and new phases of higher-dimensional rotating black holes

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    It has been conjectured that higher-dimensional rotating black holes become unstable at a sufficiently large value of the rotation, and that new black holes with pinched horizons appear at the threshold of the instability. We search numerically, and find, the stationary axisymmetric perturbations of Myers-Perry black holes with a single spin that mark the onset of the instability and the appearance of the new black hole phases. We also find new ultraspinning Gregory-Laflamme instabilities of rotating black strings and branes.Comment: 5 pages, 5 figures. The instability of the black hole is argued to appear at the second zero mode. The first zero mode is not associated to a new branch of black hole solution

    Improvements in damage detection using modal strain fields measured by digital shearography

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    In this paper we present a novel approach for damage detection based on discontinuities analysis of experimental modal strain fields. These fields are extracted from the combination of two rotation fields and they are measured using digital shearography with stroboscopic double illumination. The rotation fields of a damaged laminated plate are frozen by the synchronization between the LASER illumination and the modal vibration of the object. The quantitative evaluation is performed for each digital shearogram using a time modulation technique. The evaluation of a delamination damage on composite plates is performed by using dedicate image processing techniques. Finally, a comparative analysis of damage detections using the experimental measurement of rotation and deformation fields and their spatial derivatives is presented

    The origins of monetary policy disagreement: The role of supply and demand shocks

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    We investigate how dissent in the FOMC is affected by structural macroeconomic shocks obtained using a medium-scale DSGE model. We find that dissent is less (more) frequent when demand (supply) shocks are the predominant source of inflation fluctuations. In addition, supply shocks are found to raise private sector forecasting uncertainty about the path of interest rates. Since supply shocks impose a trade-off between inflation and output stabilization while demand shocks do not, our findings are consistent with heterogeneous preferences over the dual mandate among FOMC members as a driver of policy disagreement.info:eu-repo/semantics/acceptedVersio

    Primary and secondary scintillation measurements in a xenon Gas Proportional Scintillation Counter

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    NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC. The detector requires excellent energy resolution, which can be achieved in a Xe TPC with electroluminescence readout. Hamamatsu R8520-06SEL photomultipliers are good candidates for the scintillation readout. The performance of this photomultiplier, used as VUV photosensor in a gas proportional scintillation counter, was investigated. Initial results for the detection of primary and secondary scintillation produced as a result of the interaction of 5.9 keV X-rays in gaseous xenon, at room temperature and at pressures up to 3 bar, are presented. An energy resolution of 8.0% was obtained for secondary scintillation produced by 5.9 keV X-rays. No significant variation of the primary scintillation was observed for different pressures (1, 2 and 3 bar) and for electric fields up to 0.8 V cm-1 torr-1 in the drift region, demonstrating negligible recombination luminescence. A primary scintillation yield of 81 \pm 7 photons was obtained for 5.9 keV X-rays, corresponding to a mean energy of 72 \pm 6 eV to produce a primary scintillation photon in xenon.Comment: 16 pages, 10 figures, accepted for publication in JINS

    Tempo quente e seco antecipa parte da safra de uva 2013 e o total produzido poderá superar 2012.

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    bitstream/item/74968/1/22-01-13-uva.pdf; bitstream/item/82448/1/MONTEIRO-Agrolink-jan2013.pdfCultivar, Pelotas, 22 jan. 2013. Publicado também no site da Agrolink em 17/01/13

    Examining the Factorial Structure of the Maternal Separation Anxiety Scale in a Portuguese Sample

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    The increase in women's labor market participation emphasizes the importance of understanding maternal separation anxiety, that is, the unpleasant maternal emotional state, due to the actual or anticipated short-term separation from the child. Drawing on the insights of the attachment and psychoanalytic perspectives, the Maternal Separation Anxiety Scale (MSAS) was developed to overcome existing measurement gaps. However, prior research did not replicate its original three-factor structure in the contemporary context and in other cultural settings, using large samples composed of mothers of preschool children. This study aimed to examine the factorial structure of the MSAS in a sample of 597 Portuguese mothers of children aged 5-84 months who completed the questionnaire. The exploratory factor analysis (EFA) conducted in subsample 1 revealed a four-factor structure: Maternal Negative Feelings, Beliefs about Exclusive Maternal Care, Need of Proximity, and Perceptions of Separation Benefits for Children. Confirmatory factor analyses conducted in subsample 2 revealed that the original three-factor structure revealed a poor fit, whereas the four-factor solution (obtained in the EFA) revealed an acceptable fit. As in previous studies, our findings report deviations from the original three-factor structure of the MSAS. Three of the newly identified factors seem to reflect specific sub-dimensions that originally guided item development in the MSAS, namely, maternal negative feelings, maternal attitudes about the value of exclusive maternal care, and the need of proximity with the child. The last factor appears to represent a refinement of original items pertaining to perceptions about separation effects for children.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

    Culture, longevity and social policies - Radar's Project from the Portuguese Institution Santa Casa da Misericórdia de Lisboa

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    Culture is intrinsically linked to the values of society. Politics dictates our evolution of society through choices and omissions. Older people and their perceived value to the world must be a global priority. Still, the West has not valued this age group wisely and fairly. The data indicate that the impact of social circumstances on the quality of life of the elderly has not been of paramount importance. Investment in the scientific biosocial approach has been deficient compared to the biomedical approach. However, it has had the most significant positive impact on living standards and longevity. We recognise that the funding of the biosocial approach is not considered as competitive as the biomedical approach, because the methodology of the social sciences is fundamentally different. Public policy lacks accuracy because science cannot overrule political power. Accordingly, from 2021 to 2030, the United Nations Organization has named the decade of healthy ageing. Healthcare, as a pillar of social governance and respect for the lives of the elderly, believes that it is vital to have the necessary social support to prosper. On the basis of these circumstances, this research paper outlines the importance of focusing on the social aspect of living and ageing in assessing this age group. Healthy ageing has reflected improved living standards, and increased longevity must become a political priority. This article highlights the concept of political longevity initiatives and how to observe them from an ethical point of view of social science results in a different picture of society. The different perspectives that we present are useful for the modern science of public health. Radar is a current Portuguese initiative as a political project involving public and social institutions. We analyse this project, focusing on the importance of making healthy global ageing a political option.info:eu-repo/semantics/publishedVersio

    The Arena: An indoor mixed reality space

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    ln this paper, we introduce the Arena, an indoor space for mobile mixed reality interaction. The Arena includes a new user tracking system appropriate for AR/MR applications and a new Too/kit oriented to the augmented and mixed reality applications developer, the MX Too/kit. This too/kit is defined at a somewhat higher abstraction levei, by hiding from the programmer low-level implementation details and facilitating ARJMR object-oriented programming. The system handles, uniformly, video input, video output (for headsets and monitors), sound aurelisation and Multimodal Human-Computer Interaction in ARJMR, including, tangible interfaces, speech recognition and gesture recognition.info:eu-repo/semantics/publishedVersio
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