24 research outputs found

    Liquid 4He: contributions to first principles theory of quantized vortices, thermohydrodynamic properties, and the lambda transition

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    Liquid 4He has been studied extensively for almost a century, but there are still a number of outstanding weak or missing links in our comprehension of it. This paper reviews some of the principal paths taken in previous research and then proceeds to fill gaps and create an integrated picture with more complete understanding through first principles treatment of a realistic model that starts with a microscopic, atomistic description of the liquid. Newly derived results for vortex cores and thermohydrodynamic properties for a two-fluid model are used to show that interacting quantized vortices may produce a lambda anomaly in specific heat near the superfluid transition where flow properties change. The nature of the order in the superfluid state is explained. Experimental support for new calculations is exhibited, and a unique specific heat experiment is proposed to test predictions of the theory. Relevance of the theory to modern research in cosmology, astrophysics, and Bose-Einstein condensates is discussed.Comment: 155 pages, 28 figure

    Halogenated Organic Molecules of Rhodomelaceae Origin: Chemistry and Biology

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    Psicoterapia de criança com alopecia areata universal: desenvolvendo a resiliência

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    Este artigo apresenta um estudo de caso de uma criança portadora de alopecia areata universal, vitiligo e transtorno de ansiedade generalizada, atendida em clínica-escola de psicologia de 2002 a 2007. A abordagem terapêutica adotada foi a psicoterapia de orientação psicanalítica infantil e a orientação sistemática aos pais, objetivando a diminuição dos sintomas e o desenvolvimento de habilidades para o enfrentamento da doença crônica. No decorrer do processo, ao longo dos cinco anos de atendimento, a paciente adaptou-se positivamente à doença, ocorrendo a remissão dos sintomas de ansiedade e o desenvolvimento de comportamentos resilientes que indicaram a alta terapêutica
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