2,706 research outputs found

    The Casimir effect for the scalar and Elko fields in a Lifshitz-like field theory

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    In this work, we obtain the Casimir energy for the real scalar field and the Elko neutral spinor field in a field theory at a Lifshitz fixed point (LP). We analyze the massless and the massive case for both fields using dimensional regularization. We obtain the Casimir energy in terms of the dimensional parameter and the LP parameter. Particularizing our result, we can recover the usual results without LP parameter in (3+1) dimensions presented in the literature. Moreover, we compute the effects of the LP parameter in the thermal corrections for the massless scalar field.Comment: 20 pages, 2 figures, some results have been modified and other changes to the text have been made to match the accepted version in Eur. Phys. J.

    Bounds on topological Abelian string-vortex and string-cigar from information-entropic measure

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    In this work we obtain bounds on the topological Abelian string-vortex and on the string-cigar, by using a new measure of configurational complexity, known as configurational entropy. In this way, the information-theoretical measure of six-dimensional braneworlds scenarios are capable to probe situations where the parameters responsible for the brane thickness are arbitrary. The so-called configurational entropy (CE) selects the best value of the parameter in the model. This is accomplished by minimizing the CE, namely, by selecting the most appropriate parameters in the model that correspond to the most organized system, based upon the Shannon information theory. This information-theoretical measure of complexity provides a complementary perspective to situations where strictly energy-based arguments are inconclusive. We show that the higher the energy the higher the CE, what shows an important correlation between the energy of the a localized field configuration and its associated entropic measure.Comment: 6 pages, 7 figures, final version to appear in Phys. Lett.

    The Two-Component Virial Theorem and the Physical Properties of Stellar Systems

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    Motivated by present indirect evidences that galaxies are surrounded by dark matter halos, we investigate whether their physical properties can be described by a formulation of the virial theorem which explicitly takes into account the gravitational potential term representing the interaction of the dark halo with the barionic or luminous component. Our analysis shows that the application of such a ``two-component virial theorem'' not only accounts for the scaling relations displayed, in particular, by elliptical galaxies, but also for the observed properties of all virialized stellar systems, ranging from globular clusters to galaxy clusters.Comment: 13 pages, 2 figures, LaTeX, corrected few typos. This version matches the published versio

    As sementes da Caatinga são...: um levantamento das características das sementes da Caatinga.

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    O presente trabalho teve por objetivo realizar uma busca ampla sobre a expressão ?As sementes da caatinga são? e encontrar padrões característicos em estudos já realizados. A partir dos resultados da busca pode-se concluir que as sementes da Caatinga são produzidas durante todo o ano, mas a maioria é dispersada no final da estação seca. As sementes da Caatinga apresentam características morfofisiológicas de acordo com os locais onde são produzidas. Algumas sementes da Caatinga apresentam dormência tegumentar, no entanto, é raro encontrar dormência fisiológica. A maioria das sementes da Caatinga são apresentam tolerância a estresses abióticos, embora algumas espécies características deste ecossistema são sensíveis a algumas condições ambientais extremas. A comercialização das sementes da Caatinga ainda é incipiente. As sementes da Caatinga felizmente estão sendo estudadas em várias instituições do Nordeste, do Brasil e do mundo.Edição das Palestras do V Workshop de Tecnologia e Fisiologia de Sementes e Mudas, Petrolina, dez. 2014

    Medical abortion in Nepal: a qualitative study on women's experiences at safe abortion services and pharmacies.

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    BACKGROUND: Although Nepal legalised abortion in 2002, a significant number of women continue to access unsafe abortions. An estimated 60% of all abortions performed in 2014 were unsafe, with unsafe abortion continuing to be a leading contributor to maternal mortality. Despite medical abortion access being solely permitted through government accredited safe abortion services, medical abortion pills are readily available for illegal purchase at pharmacies throughout the country. METHODS: Utilising an Assets Focused Rapid Participatory Appraisal (AFRPA) research methodology, underpinned by a health information pyramid conceptual framework, this qualitative exploratory study collected data from in-depth, open-ended interviews. The study explored the medical abortion and sexual and reproductive health experiences of ten women who accessed medical abortion through an accredited safe abortion service, and ten women who accessed unsafe medical abortion through pharmacies. RESULTS: Thematic content analysis revealed emerging themes relating to decision-making processes in accessing safe or unsafe medical abortion; knowledge of safe abortion services; and SRH information access and post-abortion contraceptive counselling. Findings emphasised the interconnectivity of sexual and reproductive health and rights; reproductive coercion; education; poverty; spousal separation; and women's personal, social and economic empowerment. CONCLUSIONS: While barriers to safe abortion services persist, so will the continued demand for medical abortion provision through pharmacies. Innovated and effective harm reduction implementations combined with access and information expansion strategies offer the potential to increase access to safe medical abortion while decreasing adverse health outcomes for women

    Modelagem bioeconômica da transferência de embriões em bovinos.

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    O objetivo deste trabalho foi desenvolver um modelo matemático orientado a eventos de simulação, para auxiliar tomadas de decisão relativas à transferência de embriões em bovinos, considerando-se as dinâmicas de dois componentes da transferência de embriões: receptoras e embriões. Na simulação, não se avaliaram respostas individuais de doadoras a coletas consecutivas e eventos correspondentes na transferência de embriões. Simulou-se o mesmo protocolo para superovulação a todas as doadoras. Receptoras foram sincronizadas simulando-se o uso de prostaglandina. O número de embriões viáveis produzido por doadora e sua variabilidade tiveram como base um processo aleatório de simulação de Monte Carlo, que pressupôs uma distribuição exponencial negativa de densidade de probabilidade. Custos e receitas foram inseridos no modelo por meio de um cenário-base para calcular indicadores econômicos de rentabilidade. A análise sugeriu a impraticabilidade da atividade, se realizada diante do cenário proposto (VPL ? R:57.596,69).Apartirdocenaˊrioproposto,ocustomeˊdioestimadofoideR: 57.596,69). A partir do cenário proposto, o custo médio estimado foi de R 1.178,19, e de R$ 980,03, para se obter uma prenhez a partir de uma situação otimizada, sugerida pelo modelo (5/100; 5/190)
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