229 research outputs found

    Ecophysiological responses of the winegrape Chenin Blanc under different irrigation management in the São Francisco river valley.

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    The So Francisco Valley has been considered a new growing region for wine grapeproduction. In this region, the wines have a typical taste and are the unique ones producedunder tropical conditions. Because the irrigation management is one of the most importantfactors related to grape and wine quality, a study was carried out by the Embrapa Semirido,in the VINIBRASIL Farm vineyards, at Lagoa Grande, State of Pernambuco, Brazil inwhich the grapevine ¡§Chenin Blanc¡¨, grafted onto the IAC 572 rootstock, and spaced by 1,0m x 3,0 m, was submitted to different irrigation managements: T1) 75% Kc; T2) 50% Kc; T3)50 % Kc until 80 days after pruning and then 75% Kc until harvest and; T4) about 30% Kc(Farm management). Irrigation water was applied by dripping and the treatments initiated 45days after pruning. The effects of treatments were observed based on the ecophysiologicalperformance of the grapevine through measurements of leaf water potential (£Zl) obtainedwith a pressure chamber and gas exchange variables (stomatal conductance, gs;transpiration rate, E; photosynthesis, A), with a portable infrared gas analyzer (IRGA ¡V Licor6200) during flowering and maturation (August to September, 2006). The results showed thatgrapevines submitted to the T1 treatment presented the highest £Zl, gs, E and A values duringthe hottest hours of day followed by T3 and T2. The T4 treatment presented the lowestvalues on these variables but higher intrinsic water use efficiency (WUE) calculated as A/gs.At harvest, this treatment showed lower bunch number per plant and yield but higher oBrixand higher pH. The results suggest that the monitoring of the ecophysiological performanceof winegrapes during the growth cycle, might be a good tool to establish an appropriatedirrigation management toward grape and wine quality

    Repetibilidade da idade ao primeiro parto, intervalo de partos e peso ao parto em bovinos da Rraça Nelore.

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    Utilizaram-se 407 observações de idade ao primeiro parto, 971 de intervalo de partos e 587 de peso ao parto de vacas da raça Nelore, para avaliar os efeitos de alguns fatores sobre essas características e estimar seus coeficientes de repetibilidade

    A Transfer Matrix Method for Resonances in Randall-Sundrum Models

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    In this paper we discuss in detail a numerical method to study resonances in membranes generated by domain walls in Randall-Sundrum-like scenarios. It is based on similar works to understand the quantum mechanics of electrons subject to the potential barriers that exist in heterostructures in semiconductors. This method was used recently to study resonances of a three form field and lately generalized to arbitrary forms. We apply it to a lot of important models, namely those that contain the Gauge, Gravity and Spinor fields. In many cases we find a rich structure of resonances which depends on the parameters involved.Comment: 25 pages, 17 figure

    A Transfer Matrix Method for Resonances in Randall-Sundrum Models II: The Deformed Case

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    Here we consider resonances of the Gauge, Gravity and Spinor fields in Randall-Sundrum-like scenarios. We consider membranes that are generated by a class of topological defects that are deformed domain walls obtained from other previously known ones. They are obtained by a deformation procedure generate different potentials to the associated Schr\"odinger-like equation. The resonance spectra are calculated numerically using the method of Transfer Matrix developed by the authors and presented in JHEP 1108 (2011) 071. The new deformed defects change the resonances spectra of all fields considered and the associated phenomenology as well.Comment: 29 pages, 19 figure

    Influência da relação solo/planta sobre a qualidade de uvas e vinhos cv. Syrah no Nordeste do Brasil.

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    O solo é um dos fatores mais importantes que influenciam a qualidade de uvas e vinhos, além do clima e a adaptação de cultivares. Pode influenciar o desenvolvimento radicular das plantas, em função das suas características físicas, tais como a textura, profundidade, porosidade e pedregosidade, com conseqüente modificação da absorção de água e nutrientes e desenvolvimento do sistema radicular. No Vale do Submédio São Francisco, os vinhedos são obrigatoriamente irrigados devido às características climáticas da região, apresentando uma estação chuvosa (janeiro-abril) e outra estação caracterizada pela ausência de chuvas (maio-dezembro). A produção de vinhos é uma atividade recente na região, sendo necessário realizar estudos de adaptação de cultivares em função das características dos solos existentes. O presente trabalho realizou uma avaliação da qualidade de uvas e vinhos, cv. Syrah, instalada em latada em um solo arenoso com três variações, quanto à presença ou ausência de pedregosidade, sendo: T1 solo pedregoso (30% de pedras), T2 solo intermediário (15%) e T3 solo sem pedras. As plantas estão enxertadas sobre o porta-enxerto IAC-313 e irrigadas por gotejamento. As uvas foram colhidas em julho/2006, apresentando variações quanto à acidez total titulável (ATT) (T1>T2>T3), ao teor de sólidos solúveis totais (ºBrix) (T2>T1>T3) e ao peso médio de 100 bagas (T3>T2>T1). Os vinhos foram elaborados em frascos de 20 L, com a fermentação alcoólica a 25 ºC e a malolática a 18 ºC. O vinho elaborado a partir de uvas provenientes de T1 apresentou menor teor alcoólico, maior acidez e pH. Com relação à intensidade de cor, a ordem em função da concentração dos vinhos foi T1>T2>T3. O vinho do tratamento T3 apresentou maior teor alcoólico e menor acidez. Os resultados mostram que a interação solo/planta (porta-enxerto/cultivar) pode modificar a concentração de compostos em uvas e vinhos, sugerindo a necessidade de se realizar vinificações localizadas

    Prácticas docentes para creatividad en la universidad: estudio en Portugal y Brasil

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    Creativity is nowadays seen as an essential feature in higher education. Nevertheless, there is a discrepancy between the need for creativity and what higher education classrooms provide. This study assessed the perceptions of 1599 higher education students from two countries (1059 Brazilian and 540 Portuguese students), from two academic domains (Sciences and Technologies – Sc&T; Social Sciences, Arts, and Humanities – SScA&H), about the presence of creativity in their teachers’ instruction and evaluation practices. The study’s findings evidence interactive effects between the variables country and academic domain for most of the assessed factors: encouragement of new ideas, climate for the expression of ideas, and interest in students’ learning. Brazilian Sc&T students presented more negative perceptions of their classroom environments when compared to SScA&H students; Portuguese students showed opposite patterns of results. Some hypothetical explanations are discussed and future directions for research are presented.Criatividade é atualmente tomada como aspecto essencial na Educação Superior. Há, contudo, discrepância entre a necessidade de criatividade e o que a universidade proporciona. Este estudo avaliou percepções de 1599 alunos universitários de dois países (1059 brasileiros e 540 portugueses), de duas áreas curriculares (Ciências e Tecnologias – Sc&T; Ciências Sociais, Artes e Humanidades – SscA&H) sobre a presença de criatividade nas práticas docentes, instrucionais e avaliativas, de que são alvo. Os resultados mostraram efeitos interativos significativos entre as variáveis país e área curricular para a maioria dos fatores avaliados: encorajamento de novas ideias, clima para expressão de ideias e interesse pela aprendizagem dos alunos. Os estudantes brasileiros de Sc&T mostraram percepções mais negativas da sala de aula, comparados com os de SScA&H; os alunos portugueses obtiveram padrões opostos nos resultados. Algumas hipóteses explicativas são discutidas e são apresentadas orientações para pesquisa futura.La creatividad está actualmente considerada como aspecto esencial en la Educación Superior. Sin embargo, existe discrepancia entre la necesidad de creatividad y lo que la universidad ofrece. Este estudio evaluó percepciones de 1.599 estudiantes universitarios (1.059 de Brasil y 540 de Portugal) de dos áreas curriculares (Ciencia y Tecnología – Sc&T; Ciencias Sociales, Artes y Humanidades – SscA&T) acerca de la presencia de creatividad en las prácticas docentes, instructivas y evaluativas dirigidas a ellos. Los resultados mostraron efectos de interacción significativos entre las variables país y área curricular para la mayoría de los factores evaluados: fomento de nuevas ideas, entorno para la expresión de ideas e interés en el aprendizaje del estudiante. Los estudiantes brasileños de Sc&T mostraron percepciones más negativas de la clase en comparación con los de SSCA&H; los estudiantes portugueses obtuvieron patrones opuestos en los resultados. Algunas hipótesis explicativas se discuten y se presentan directrices para investigación futura.Thermo Scientificinfo:eu-repo/semantics/publishedVersio

    Searching for Young M Dwarfs with GALEX

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    The census of young moving groups in the solar neighborhood is significantly incomplete in the low-mass regime. We have developed a new selection process to find these missing members based on the GALEX All-Sky Imaging Survey. For stars with spectral types >K5 and younger than 300~Myr, we show that near-UV and far-UV emission is greatly enhanced above the quiescent photosphere, analogous to the enhanced X-ray emission of young low-mass stars seen by ROSAT but detectable to much larger distances with GALEX. By combining GALEX data with optical (HST Guide Star Catalog) and near-IR (2MASS) photometry, we identified an initial sample of 34 young M dwarf candidates in a 1000 sq.~deg.~region around the 10-Myr TW Hydra Association (TWA). Low-resolution spectroscopy of 30 of these found 16 which had H_alpha in emission, which were then followed-up at high resolution to search for spectroscopic evidence of youth and to measure radial velocities. Four objects have low surface gravities, photometric distances and space motions consistent with TWA, but the non-detection of Li indicates they may be too old to belong to this moving group. One object (M3.5, 93 pc) appears to be the first known accreting low-mass member of the 15~Myr Lower Centaurus Crux OB association. Two objects exhibit all the characteristics of the known TWA members, and thus we designate them as TWA 31 (M4.2, 110 pc) and TWA 32 (M6.3, 53 pc). TWA 31 shows extremely broad (447 km/s) H_alpha emission, making it the sixth member of TWA found to have ongoing accretion. TWA 32 is resolved into a 0.6" binary in Keck laser guide star adaptive optics imaging. Our search should be sensitive down to spectral types of at least M4-M5 in TWA and thus the small numbers of new member is puzzling. This may indicate TWA has an atypical mass function or that the presence of Li may be too restrictive a criteria for selecting young low-mass stars.Comment: Accepted to Ap
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