4,623 research outputs found

    Quantum stress tensor for massive vector field in the space-time of a cylindrical black hole

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    The components of the renormalized quantum Energy-Momentum tensor for a massive vector field coupled to the gravitational field configuration of a static Black-String are analytically evaluated using the Schwinger-DeWitt approximation. The general results are employed to investigate the pointwise energy conditions for the quantized matter field, and it is shown that they are violated at some regions of the spacetime, in particular the horizon of the black hole.Comment: 4 pages, 3 figure

    Quantization of massive scalar fields over static black string backgrounds

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    The renormalized mean value of the corresponding components of the Energy-Momentum tensor for massive scalar fields coupled to an arbitrary gravitational field configuration having cylindrical symmetry are analytically evaluated using the Schwinger-DeWitt approximation, up to second order in the inverse mass value. The general results are employed to explicitly derive compact analytical expressions for the Energy-Momentum tensor in the particular background of the Black-String spacetime. In the case of the Black String considered in this work, we proof that a violation of the weak energy condition occur at the horizon of the space-time for values of the coupling constant, that include as particular cases the most interesting of minimal and conformal coupling.Comment: 4 page

    Usage of social and semantic web technologies to design a searching architecture for software requirement artefacts

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    At present, the research community recognises a complementary relationship between the semantic and the social web. The merging of these web instances could play an essential role in different knowledge domains. In this study, the authors promote a social–semantic web paradigm using software engineering as the knowledge domain specifically. The authors address a major problem – the difficulty for end-users in finding documentation related to software requirements proposed by them; this fact reduces their participation at the time of specifying the software requirements. Architecture is proposed for enhanced resources search, combining the strengths of the social (social annotations) and semantic (semantic metadata) technologies, which has been designed considering the search style of the information seekers. Such architecture is applied in a use-scenario, where the expert users who are not technicians have some restrictions and limitations to retrieve the documents they need. The preliminary results demonstrate that it is possible to take advantage of the defined infrastructure of the ontology to organise and integrate the metadata of resources which are in databases or existent files; this approach opens several possibilities as creation and validation of software requirements collaboratively among different expert-users

    Case Series: Gene Expression Analysis in Canine Vogt-Koyanagi-Harada/Uveodermatologic Syndrome and Vitiligo Reveals Conserved Immunopathogenesis Pathways Between Dog and Human Autoimmune Pigmentary Disorders

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    Vogt-Koyanagi-Harada syndrome (VKH) and vitiligo are autoimmune diseases that target melanocytes. VKH affects several organs such as the skin, hair follicle, eyes, ears, and meninges, whereas vitiligo is often limited to the skin and mucosa. Many studies have identified immune genes, pathways and cells that drive the pathogeneses of VKH and vitiligo, including interleukins, chemokines, cytotoxic T-cells, and other leukocytes. Here, we present case studies of 2 canines with VKH and 1 with vitiligo, which occurred spontaneously in client-owned companion dogs. We performed comparative transcriptomics and immunohistochemistry studies on lesional skin biopsies from these cases in order to determine if the immunopathogenesis of autoimmune responses against melanocytes are conserved. In dogs, we found enrichment of T cell gene signatures, with upregulation of IFNG, TNF, PRF1, IL15, CTSW, CXCL10, and CCL5 in both VKH and vitiligo in dogs compared to healthy controls. Similar findings were reported in humans, suggesting that these genes play a role in the pathogenesis of spontaneous VKH and vitiligo. T cell-associated genes, including FOXP3 and TBX21, were enriched, while IGFBP5, FOXO1, and PECAM1 were decreased compared to healthy controls. Further, we identified TGFB3, SFRP2, and CXCL7 as additional potential drivers of autoimmune pigmentary disorders. Future studies exploring the immunopathogenesis of spontaneous autoimmunity will expand our understanding of these disorders, and will be useful in developing targeted therapies, repurposing drugs for veterinary and human medicine, and predicting disease prognosis and treatment response
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