2,041 research outputs found

    Design of the EURISOL multi-MW target assembly: radiation and safety issues

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    The multi-MW target proposed for the EURISOL facility will be based on fission of uranium (or thorium) compounds to produce rare isotopes far from stability. A two-step process is used for the isotope production. First, neutrons are generated in a liquid mercury target, irradiated by the 1 GeV proton or deuteron beam, provided by the EURISOL linac driver. Then, the neutrons induce fission in a surrounding assembly of uranium carbide. R&D projects on several aspects of the target assembly are ongoing. Key criteria for the target design are a maximum beam power capability of 4 MW, a remote handling system with minimum downtime and maximum reliability, as well as radiation safety, minimization of hazards and the classification of the facility. In the framework of the ongoing radiation characterization and safety studies, radiation transport simulations have been performed to calculate the prompt radiation dose in the target and surrounding materials, as well as to determine shielding material and angle-dependent parameters. In this paper, we report the results of these studies and the proposed radiation shield design for the multi-MW target area. Furthermore, accurate estimates have been performed of the amount of fissile elements being produced in the uranium target assembly, for typical running conditions, in order to understand the implications for the classification of the facility. The results are reported and briefly discussed.Comment: 11 pages,5 figures, Invited talk at the SATIF-8 Workshop, May 22-24,2006, Pohang Accelerator Laboratory, Rep. Of Kore

    Influence of rootstocks and pruning times on yield and on nutrient content and extraction in 'Niagara Rosada' grapevine.

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    The objective of this work was to evaluate the influence of rootstocks and pruning times on yield and on nutrient content and extraction by pruned branches and harvested bunches of 'Niagara Rosada' grapevine in subtropical climate. The rootstocks 'IAC 766', 'IAC 572', 'IAC 313', 'IAC 571‑6', and '106‑8 Mgt' were evaluated. Treatments consisted of a combination between five rootstocks and three pruning times. At pruning, fresh and dry matter mass of branches were evaluated to estimate biomass accumulation. At harvest, yield was estimated by weighing of bunches per plant. Branches and bunches were sampled at pruning and at harvest, respectively, for nutrient content analysis. Nutrient content and dry matter mass of branches and bunches were used to estimate total nutrient extraction. 'Niagara Rosada' grapevine grafted onto the 'IAC 572' rootstock had the highest yield and dry matter mass of bunches, which were significantly different from the ones observed in 'Niagara Rosada'/'IAC 313'. 'Niagara Rosada' grafted onto the 'IAC 572' rootstock extracted the largest quantity of K, P, Mg, S, Cu, and Fe, differing from 'IAC 313' and 'IAC 766' in K and P extraction, and from '106‑8 Mgt' in Mg and S extraction. Winter pruning results in higher yield, dry matter accumulation by branches, and total nutrient content and extraction.Título em português: Influência de porta?enxertos e épocas de poda na produtividade e no teor e na extração de nutrientes na videira 'Niagara Rosada'

    Desenvolvimento vegetativo e tensão da água no solo em videiras para suco sobre dois porta-enxertos.

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    RESUMO: O presente trabalho teve por objetivo avaliar o efeito de dois porta-enxertos sobre o desenvolvimento vegetativo e as tensões da água no solo em videiras destinadas à elaboração de suco, sob condições irrigadas. As avaliações foram realizadas de agosto a dezembro de 2015 no município de Votuporanga (SP), com a cultivar Isabel Precoce enxertada sobre os portaenxertos ?IAC 572? e ?IAC 766?. As plantas foram sustentadas no sistema espaldeira e irrigadas por microaspersores. Tensiômetros foram instalados a 0,10 m e 0,30 m de profundidade, para monitorar as tensões da água no solo. Foram determinados os índices de área foliar, a altura da copa e a porcentagem da área sombreada das videiras. As tensões da água no solo apresentaram comportamento semelhante nos dois porta-enxertos. Não foram observadas diferenças significativas entre as variáveis de crescimento vegetativo nas videiras. Concluiu-se que os porta-enxertos ?IAC 572? e ?IAC 766? não afetaram o desenvolvimento vegetativo e as tensões da água no solo para a cultivar Isabel Precoce, em condições irrigadas. PALAVRAS-CHAVE: viticultura, irrigação, evapotranspiraçã

    Indução da brotação de videira da cultivar niágara rosada com o uso de ERGER® associado a nitrato de cálcio em Botucatu, SP.

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    A utilização de indutores de brotação em fruteiras de origem de clima temperado é uma prática consolidada em todas regiões do Brasil e do mundo. Em videiras, assim como em outras frutíferas temperadas, o Dormex® é o produto mais utilizado devido sua alta eficiência. Pelo fato de não existir outros promotores de brotação com sua eficácia, seu valor financeiro e elevado nível toxicológico são barreiras que os produtores encaram para manter a produção vitícola. Resultados promissores na literatura indicam que o Erger® associado ao nitrato de cálcio apresentam influencia na brotação de frutíferas de clima temperado

    Estimativa dos coeficientes de cultivo (kc) de videiras para suco.

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    A fração da área coberta pelo dossel (fc) tem sido empregada, em diferentes regiões, para a estimativa do coeficiente de cultivo (Kc) de videiras. O presente trabalho teve por objetivo estimar os valores de Kc de videiras destinadas à produção de uvas para elaboração de suco com base nos valores de fc, nas condições do noroeste paulista. As avaliações foram realizadas de agosto a novembro de 2016 no município de Votuporanga (SP), com as cultivares Isabel Precoce e BRS Carmem enxertadas sobre os porta-enxertos ?IAC 572? e ?IAC 766?. As videiras foram conduzidas no sistema espaldeira e irrigadas por microaspersores. Os valores de fc foram obtidos ao longo do ciclo da cultura e correlacionados à soma térmica diária (ST) por meio de modelos de regressão. Os coeficientes de cultivo (Kc), foram obtidos em função da fc com base no modelo de Allen e Pereira (2009). Para a cultivar BRS Carmem, os valores de fc em função de ST cresceram de forma contínua, segundo um modelo quadrático, enquanto que, para a cultivar Isabel Precoce, os dados se ajustaram melhor ao modelo de Mitscherlich, apresentando um rápido crescimento inicial e se estabilizando após 500 °C dia, aproximadamente. Os valores médios estimados de Kc para as cultivares Isabel Precoce e BRS Carmem foram iguais a 0,81 e 0,74, respectivamente. O modelo empregado nas avaliações permite a realização de estimativas dos valores de Kc para diferentes condições de cultivo

    Phytochemical profile of Brazilian grapes (Vitis labrusca and hybrids) grown on different rootstocks.

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    Important factors may influence the bioactive compounds in grapes, including scion–rootstock interaction. Therefore, the bioactive compounds and antioxidant activity in grape skin and pulp fractions of ‘Isabel Precoce’, ‘BRS Carmem’, ‘BRS Cora’, ‘BRS Violeta’ and ‘IAC 138–22 Ma´ximo’ were assessed. These cultivars, from genetic improvement programs in Brazil, have good adaptation to subtropical and tropical climate conditions, and can be widely used by winegrowers aiming at adding value to the grape. All grapevines were grafted onto ‘IAC 766’ and ‘IAC 572’ rootstocks under tropical conditions in Brazil. The highest concentration of bioactive compounds was found in skins of ‘BRS Violeta’, followed by ‘IAC 138–22 Ma´ ximo’, both grafted onto ‘IAC 766’. There was a strong correlation between phenolic content and antioxidant properties, since antioxidant activity also decreased in the sequence: ‘BRS Violeta’ > ‘IAC 138–22 Ma´ximo’ > ‘BRS Cora’ > ‘BRS Carmem’ > ‘Isabel Precoce’. Skin from hybrid grapes (‘BRS Violeta’, ‘IAC 138–22 Ma´ximo’, ‘BRS Cora’ and ‘BRS Carmem’) grafted in both rootstocks contains higher levels of (poly)phenolic compounds and antioxidant activity than ‘Isabel Precoce’ (V. labrusca). Skin from ‘BRS Violeta’ grafted onto ’IAC 766’ stand out from the others due to their high content of bioactive compounds

    Uso de Erger® associado ao nitrato de cálcio na produção e qualidade de uvas "Niagara Rosada" cultivadas em Botucatu, SP.

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    A busca por produtos alternativos para a quebra de dormência de frutíferas de clima temperado, que possuam alta eficiência de brotação, menor risco ao ambiente e a saúde humana, impulsiona pesquisas no setor vitícola

    Evidence for t\bar{t}\gamma Production and Measurement of \sigma_t\bar{t}\gamma / \sigma_t\bar{t}

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    Using data corresponding to 6.0/fb of ppbar collisions at sqrt(s) = 1.96 TeV collected by the CDF II detector, we present a cross section measurement of top-quark pair production with an additional radiated photon. The events are selected by looking for a lepton, a photon, significant transverse momentum imbalance, large total transverse energy, and three or more jets, with at least one identified as containing a b quark. The ttbar+photon sample requires the photon to have 10 GeV or more of transverse energy, and to be in the central region. Using an event selection optimized for the ttbar+photon candidate sample we measure the production cross section of, and the ratio of cross sections of the two samples. Control samples in the dilepton+photon and lepton+photon+\met, channels are constructed to aid in decay product identification and background measurements. We observe 30 ttbar+photon candidate events compared to the standard model expectation of 26.9 +/- 3.4 events. We measure the ttbar+photon cross section to be 0.18+0.08 pb, and the ratio of the cross section of ttbar+photon to ttbar to be 0.024 +/- 0.009. Assuming no ttbar+photon production, we observe a probability of 0.0015 of the background events alone producing 30 events or more, corresponding to 3.0 standard deviations.Comment: 9 pages, 3 figure

    Inclusive Search for Anomalous Production of High-pT Like-Sign Lepton Pairs in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV

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    We report on a search for anomalous production of events with at least two charged, isolated, like-sign leptons with pT > 11 GeV/c using a 107 pb^-1 sample of 1.8 TeV ppbar collisions collected by the CDF detector. We define a signal region containing low background from Standard Model processes. To avoid bias, we fix the final cuts before examining the event yield in the signal region using control regions to test the Monte Carlo predictions. We observe no events in the signal region, consistent with an expectation of 0.63^(+0.84)_(-0.07) events. We present 95% confidence level limits on new physics processes in both a signature-based context as well as within a representative minimal supergravity (tanbeta = 3) model.Comment: 15 pages, 4 figures. Minor textual changes, cosmetic improvements to figures and updated and expanded reference
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