36,388 research outputs found

    Is the effect of birth weight on early breast cancer mediated through childhood growth?

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    Avaliação do potencial inseticida de taninos obtidos a partir de resíduos do processamento agroindustrial de castanha-do-brasil (Bertholletia Excelsa).

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    A produção de castanha-do-Brasil (Bertholletia excelsa Humb & Bompl), gera uma grande quantidade de resíduos durante o processo de extração das suas amêndoas. Objetivou-se neste trabalho avaliar as possíveis interferências biológicas da ingestão de dieta artificial contaminada com uma fração do extrato da casca de amêndoas de B. excelsa sobre lagartas de Spodoptera frugiperda. Foram testadas as seguintes concentrações: 5%; 4,5%; 4%; 3,5%; 3%; 2,5%; 2%; 1,5% (v v-1) e testemunha. Os bioensaios de ingestão de dieta artificial contaminada foram desenvolvidos utilizando lagartas de, aproximadamente de 3º instar. Foram avaliadas as seguintes variáveis: mortalidade, duração dos estágios larval e pupal, quantidade e peso de pupas, mortalidade de pupas, larvas e adultos, deformidades dos insetos e peso da massa de ovos de fêmeas. Foram considerados significativos os valores numéricos relativos a cada interferência biológica, calculados para cada concentração do extrato, quando esses valores foram superiores ao valor obtido entre os tratamentos e /ou em relação á testemunha, considerando-se as possíveis sobreposições com o erro padrão da média de cada tratamento. Com relação à mortalidade de larvas e pupas de S. frugiperda não houve linearidade da dose-resposta esperada, sendo que na concentração 3,5% observou-se maior mortalidade do que na concentração 5%. Nas lagartas alimentadas com dieta contendo concentrações de 4,5% e 5% do extrato houve maior rejeição no consumo da exúvia, e acréscimo de 3 dias em média, com relação ao período médio de desenvolvimento larval da testemunha

    Statistics of turbulence in the energy-containing range of Taylor-Couette compared to canonical wall-bounded flows

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    Considering structure functions of the streamwise velocity component in a framework akin to the extended self-similarity hypothesis (ESS), de Silva \textit{et al.} (\textit{J. Fluid Mech.}, vol. 823,2017, pp. 498-510) observed that remarkably the \textit{large-scale} (energy-containing range) statistics in canonical wall bounded flows exhibit universal behaviour. In the present study, we extend this universality, which was seen to encompass also flows at moderate Reynolds number, to Taylor-Couette flow. In doing so, we find that also the transversal structure function of the spanwise velocity component exhibits the same universal behaviour across all flow types considered. We further demonstrate that these observations are consistent with predictions developed based on an attached-eddy hypothesis. These considerations also yield a possible explanation for the efficacy of the ESS framework by showing that it relaxes the self-similarity assumption for the attached eddy contributions. By taking the effect of streamwise alignment into account, the attached eddy model predicts different behaviour for structure functions in the streamwise and in the spanwise directions and that this effect cancels in the ESS-framework --- both consistent with the data. Moreover, it is demonstrated here that also the additive constants, which were previously believed to be flow dependent, are indeed universal at least in turbulent boundary layers and pipe flow where high-Reynolds number data are currently available.Comment: accepted in J. Fluid Mec

    The class of n-entire operators

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    We introduce a classification of simple, regular, closed symmetric operators with deficiency indices (1,1) according to a geometric criterion that extends the classical notions of entire operators and entire operators in the generalized sense due to M. G. Krein. We show that these classes of operators have several distinctive properties, some of them related to the spectra of their canonical selfadjoint extensions. In particular, we provide necessary and sufficient conditions on the spectra of two canonical selfadjoint extensions of an operator for it to belong to one of our classes. Our discussion is based on some recent results in the theory of de Branges spaces.Comment: 33 pages. Typos corrected. Changes in the wording of Section 2. References added. Examples added. arXiv admin note: text overlap with arXiv:1104.476

    Perceptions of future leaders towards business ethics and sustainability

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    This paper examines the perception of business students (BS) concerning business ethics (BE) and sustainable operations management (SOM), in cases reporting ethical dilemmas. The BS have not previously attended any specific course, either dealing with BE, SOM or providing training in ethics. A test administered to 60 BS enabled to picture perceptions regarding: (i) ethical maturity level based on general education/personal sensitivity; and (ii) ethical decision-making processes of BS. The study also determined that BS have a surprisingly high ethical maturity. However, they are not sensitive to BE/SOM scientific’ research importance. Findings point out to development of Business School curricula

    Double beta decay of 48^{48}Ca

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    48^{48}Ca, the lightest double beta decay candidate, is the only one simple enough to be treated exactly in the nuclear shell model. Thus, the ββ(2ν)\beta\beta(2\nu) half-life measurement, reported here, provides a unique test of the nuclear physics involved in the ββ\beta\beta matrix element calculation. Enriched 48^{48}Ca sources of two different thicknesses have been exposed in a time projection chamber, and yield T1/22ν=(4.3−1.1+2.4[stat.]±1.4[syst.])×1019_{1/2}^{2\nu} = (4.3^{+2.4}_{-1.1} [{\rm stat.}] \pm 1.4 [{\rm syst.}]) \times 10^{19} years, compatible with the shell model calculations.Comment: 4 pages, LaTex, 3 figures imbedded, PRL forma
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