36 research outputs found

    Stochastic backgrounds of relic gravitons: a theoretical appraisal

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    Stochastic backgrounds or relic gravitons, if ever detected, will constitute a prima facie evidence of physical processes taking place during the earliest stages of the evolution of the plasma. The essentials of the stochastic backgrounds of relic gravitons are hereby introduced and reviewed. The pivotal observables customarily employed to infer the properties of the relic gravitons are discussed both in the framework of the Λ\LambdaCDM paradigm as well as in neighboring contexts. The complementarity between experiments measuring the polarization of the Cosmic Microwave Background (such as, for instance, WMAP, Capmap, Quad, Cbi, just to mention a few) and wide band interferometers (e.g. Virgo, Ligo, Geo, Tama) is emphasized. While the analysis of the microwave sky strongly constrains the low-frequency tail of the relic graviton spectrum, wide-band detectors are sensitive to much higher frequencies where the spectral energy density depends chiefly upon the (poorly known) rate of post-inflationary expansion.Comment: 94 pages, 32 figure

    Formação científica e prática profissional na trajetória de Carlos Chagas Filho Scientific training and professional practice in the career of Carlos Chagas Filho

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    Aborda a formação científica de Carlos Chagas Filho, entre 1926 e 1942, período de socialização do cientista na Faculdade de Medicina do Rio de Janeiro e no Instituto Oswaldo Cruz. Abrange desde o início de sua atuação profissional até o momento em que deixou a direção do Serviço de Estudos de Grandes Endemias, em 1942, para se dedicar à carreira acadêmica no Laboratório de Física Biológica. Analisa o modo como seus recursos científicos e sociais foram acionados ao longo de sua trajetória, visando observar o momento em que rompeu com a tradição de pesquisa biomédica de Manguinhos e se lançou na construção de um novo local em que pudesse implantar seu projeto científico.<br>The study dwells on the scientific background of Carlos Chagas Filho, between 1926 and 1942, which was the period of socialization of the scientist in the Faculdade de Medicina do Rio de Janeiro and the Instituto Oswaldo Cruz. It covers the period from the beginning of his professional career to the moment when he resigned from the administration of the Serviço de Estudos de Grandes Endemias in 1942 to devote himself to his academic career at the Laboratório de Física Biológica. The way in which his social and scientific resources were deployed throughout his career is analyzed, with a view to ascertaining the moment when he broke with the tradition of biomedical research of Manguinhos and embarked on the construction of a new location where he could implement his own scientific project

    The sense of hearing in the Pacific oyster, Magallana gigas

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    There is an increasing concern that anthropogenic noise could have a significant impact on the marine environment, but there is still insufficient data for most invertebrates. What do they perceive? We investigated this question in oysters Magallana gigas (Crassostrea gigas) using pure tone exposures, accelerometer fixed on the oyster shell and hydrophone in the water column. Groups of 16 oysters were exposed to quantifiable waterborne sinusoidal sounds in the range of 10 Hz to 20 kHz at various acoustic energies. The experiment was conducted in running seawater using an experimental flume equipped with suspended loudspeakers. The sensitivity of the oysters was measured by recording their valve movements by high-frequency noninvasive valvometry. The tests were 3 min tone exposures including a 70 sec fade-in period. Three endpoints were analysed: the ratio of responding individuals in the group, the resulting changes of valve opening amplitude and the response latency. At high enough acoustic energy, oysters transiently closed their valves in response to frequencies in the range of 10 to <1000 Hz, with maximum sensitivity from 10 to 200 Hz. The minimum acoustic energy required to elicit a response was 0.02 m∙s-2 at 122 dBrms re 1 μPa for frequencies ranging from 10 to 80 Hz. As a partial valve closure cannot be differentiated from a nociceptive response, it is very likely that oysters detect sounds at lower acoustic energy. The mechanism involved in sound detection and the ecological consequences are discussed

    A contribuição dos estudos transculturais dos países latino-americanos e caribenhos para a revisão da CID-10: resultados preliminares The contribution of Latin American and Caribbean countries on culture bound syndromes studies for the ICD-10 revision: key findings from a working in progress

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    OBJETIVO: Esta revisão visa identificar as evidências dos estudos de países da América Latina e do Caribe para a inclusão das síndromes transculturais na versão da Classificação Internacional de Doenças para sua 11ª Edição. MÉTODO: Os estudos foram identificados nas bases do Medline, LILACS e EMBASE, no período de 1992 a 2008, e classificados segundo o tipo de estudo, tipo de transtorno, país e número de publicações por ano. RESULTADOS: Foram selecionadas e classificadas 163 publicações: 33 no Medline, 90 no EMBASE e 40 no LILACS. A percentagem das síndromes transculturais ("culture bound-syndrome") correspondeu a 9% no Medline, 12% no EMBASE e 2,5% no LILACS. Dos 15 estudos sobre síndromes transculturais, dois eram sobre "nervios e ataque de nervios", dois sobre "susto", quatro sobre a relação entre crenças religiosas, "feitiçaria", transe e apresentação dos transtornos mentais, um sobre proposta de uma nova categoria diagnóstica, três artigos teóricos e três sobre psicopatoplastia dos transtornos mentais. CONCLUSÃO: A escassez de estudos sobre síndromes transculturais pode ter ocorrido pela dificuldade em rastrear os estudos por problema de indexação das publicações, falta de interesse em publicar tais estudos em periódicos indexados e a dificuldade de acesso às publicações. Dentre os estudos identificados, não há uma evidência clara que aponte quais modificações são necessárias nas classificações diagnósticas atuais.<br>OBJECTIVE: This review aims to verify the scientific evidences for the inclusion of culture bound syndromes in the International Classification of Diseases towards its 11th edition based on studies from Latin American and Caribbean countries. METHOD: Studies were identified in Medline, LILACS and EMBASE databases for the period between 1992 and 2008, and then classified according to the type of study, to the mental disorder, country and number of publications per year. RESULTS: 163 studies were selected and classified: 33 in MedlLne, 90 in EMBASE e 40 in LILACS. The percentage of culture bound-syndrome corresponded to 9% in Medline, 12% in EMBASE e 2.5% in LILACS. Among fifteen studies on cultural bound syndromes, two were about "nervios and ataque de nervios", two about "susto", four about the relationship between religion beliefs, witchery, trance and mental disorders, one with a proposal for new diagnostic category, three about theoretic issues and three about the pathoplasty of mental disorders. CONCLUSION: The scarcity of studies on culture bound syndromes might be due to the indexation problems hindering the screening of studies; lack of interest on publishing such studies in indexed journals (publication bias) and due to difficulty to access them. There is no robust evidence identified among cross-cultural studies to recommend changes for International Classification of Diseases-11th edition
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