53 research outputs found

    Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles

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    We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e,ep)γ(e,e'p)\gamma exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the WW-dependence at fixed Q2=1Q^2=1 GeV2^2, and for the Q2Q^2-dependence at fixed WW near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q2Q^2-dependence is smooth. The measured ratio of H(e,ep)γ(e,e'p)\gamma to H(e,ep)π0(e,e'p)\pi^0 cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to Real Compton Scattering (RCS) at high energy and large angles, our VCS data at the highest WW (1.8-1.9 GeV) show a striking Q2Q^2- independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.Comment: 20 pages, 8 figures. To appear in Phys.Rev.

    The T2K experiment

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    The T2K experiment is a long baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle θ13 by observing νe appearance in a νμ beam. It also aims to make a precision measurement of the known oscillation parameters, and sin22θ23, via νμ disappearance studies. Other goals of the experiment include various neutrino cross-section measurements and sterile neutrino searches. The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC. This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem

    Efeito do pastejo rotacionado e alternado com bovinos adultos no controle da verminose em ovelhas Effect of rotational and alternate grazing with adult cattle on the control of nematode parasites in sheep

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    Estudaram-se os efeitos do pastejo alternado de ovinos e bovinos e do pastejo rotacionado sobre o controle da verminose em ovelhas. Utilizou-se uma área experimental composta por três módulos de 1,67ha cada. Os módulos foram subdivididos em oito piquetes. Vinte ovelhas foram colocadas no módulo 1 e quatro bovinos adultos no módulo 2. Os animais permaneceram em cada piquete do módulo por cinco dias, totalizando 40 dias de permanência em cada módulo. Ao final desse período, as ovelhas foram transferidas para o módulo onde estavam os bovinos e estes para o módulo onde estavam os ovinos, mantendo esse esquema até o final do experimento. Um grupo-controle de 20 ovelhas foi mantido, também em sistema rotacionado, em um terceiro módulo, sem compartilhar a pastagem. As ovelhas submetidas ao manejo com bovinos apresentaram o menor grau de infecção por nematódeos gastrintestinais e os maiores valores de volume globular. O pastejo rotacionado de ovinos, sem a utilização de bovinos, não foi eficiente no controle da verminose das ovelhas. A utilização do pastejo rotacionado e alternado de ovinos e bovinos adultos exerceu efeito benéfico significativo no controle da verminose ovina.<br>The effects of rotational and alternate grazing involving cattle and sheep on the control of nematode parasites in sheep were evaluated. Three areas with 1.67ha were subdivided into eight paddocks each. Twenty ewes and four cattle were allotted to areas 1 and 2, respectively. They grazed during five days in each of eight paddocks of each area. The sheep and cattle rotated in each area for 40 days. At the end of this period, ewes were transferred to the area where cattle were previously kept and these animals were transferred to the area where sheep had previously grazed. This arrangement was kept until the end of the experiment. A control group with 20 ewes rotated in the third area, also with eight paddocks. Ewes that alternately grazed with cattle showed the lowest fecal egg counts and the highest values of packed cell volume. The rotational grazing of sheep, without cattle, was not efficient to control gastrointestinal nematodes. The alternate grazing of sheep and cattle resulted in a reduction of parasitic infection in the ewes

    Redução de perdas pós-colheita em tomate de mesa acondicionado em três tipos de caixas Reduction of tomato post-harvest losses stored in three different types of boxes

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    Atualmente, no Brasil, a embalagem mais usada para tomate continua sendo a caixa de madeira que era usada para transportar querosene na segunda guerra mundial, há meio século, conhecida como caixa "K". Esta embalagem possui características que favorecem as injúrias mecânicas e comprometem a durabilidade e qualidade das hortaliças, como o fato de apresentar superfície áspera, alojar patógenos, profundidade excessiva, possuir aberturas laterais cortantes. Considerando os problemas da caixa K e a necessidade de proteção do tomate, a Embrapa Hortaliças iniciou, em janeiro de 1997, pesquisa para geração de uma embalagem adequada para acondicionamento e transporte de tomate. A embalagem definitiva foi testada em relação à caixa 'K' e caixa de plástico existente no mercado. Nos frutos de tomate foram avaliados a variação de matéria fresca, vida útil, cor, danos mecânicos, variação da firmeza, teor relativo de água e deterioração. A nova embalagem foi nomeada caixa Embrapa e apresenta menores percentagens de danos mecânicos, provavelmente a característica mais importante avaliada, reduzindo perdas pós-colheita em tomate de mesa.<br>The most common box used for harvested vegetables in Brazil is the wood one which was used for kerosene transporting during second world war, in 1945. This box causes mechanical damage and reduces vegetables shelf-life and quality, due to its rough surface allowing pathogen colonization, due to the excessive number of fruit layers, and due to the lateral cut openings. Considering the problems of the K box and the necessity of protecting tomato fruits, Embrapa Hortaliças began in January 1997 a research to develop an adequate box to protect tomato fruits. The definitive box, named "Embrapa box", was compared with the K box and the most common plastic boxes from the market. The weight, shelf-life, color, mechanical damage, firmness, relative water content and deterioration were evaluated. The damage was significantly different and lower in the Embrapa box, reducing post-harvest losses in tomato fruits
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