3,325 research outputs found

    Indicadores para a avaliação da disponibilidade hídrica para o desenvolvimento sustentável da atividade canavieira irrigada.

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    Para a racionalização do uso dos recursos hídricos e promoção do desenvolvimento sustentável da atividade canavieira na região Centro-Oeste torna-se importante o desenvolvimento de procedimentos metodológicos que possam fornecer subsídios técnicos para o planejamento e gestão setorial - agricultura e recursos hídricos. O presente trabalho apresenta dois indicadores concebidos para a avaliação do potencial da disponibilidade hídrica para atender a demanda projetada de água para o desenvolvimento da atividade canavieira

    Sistema de indicadores para a avaliação da sustentabilidade hídrica da atividade canaviera.

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    O objetivo deste trabalho é apresentar um estudo de caso realizado na Bacia Hidrográfica do Rio Verde (BHRV) para demonstrar a aplicabilidade do Sistema de Indicadores - SISHidro-Cana - para a avaliação da sustentabilidade hídrica da cultura canavieira, proposta por Ferraz (2012), como uma metodologia para avaliar a disponibilidade de água de bacias hidrográficas para subsidiar a proposição de políticas setoriais, ordenação territorial, planejamento agrícola e gestão dos recursos hídricos

    The Mid-Infrared Instrument for the James Webb Space Telescope, V: Predicted Performance of the MIRI Coronagraphs

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    The imaging channel on the Mid-Infrared Instrument (MIRI) is equipped with four coronagraphs that provide high contrast imaging capabilities for studying faint point sources and extended emission that would otherwise be overwhelmed by a bright point-source in its vicinity. Such bright sources might include stars that are orbited by exoplanets and circumstellar material, mass-loss envelopes around post-main-sequence stars, the near-nuclear environments in active galaxies, and the host galaxies of distant quasars. This paper describes the coronagraphic observing modes of MIRI, as well as performance estimates based on measurements of the MIRI flight model during cryo-vacuum testing. A brief outline of coronagraphic operations is also provided. Finally, simulated MIRI coronagraphic observations of a few astronomical targets are presented for illustration

    Asymmetric Synthesis of Cyclohexene Nucleoside Analogues

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    The asymmetric synthesis of novel cyclohexene nucleoside analogues 12 and 15 is described. An enantiospecific DielsAlder reaction between (E,E)-diene 2 and (+)-5-(D-mentyloxy)-2(5H)- furanone 3 provided the cycloadduct isomer 4. Three additional steps yielded amine 8 allowing the constructions of the thymine and adenine moieties to afford intermediates 11 and 14, respectively. Amination or cyclization and removal of the protecting groups occurred in one step in the presence of ammonia, giving the target six-membered ring nucleosides

    COMPARAISON DES PRECIPITATIONS PENDANT LA PERIODE DE CULTURE DE SOJA DANS DEUX REGIONS AU BRESIL

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    International audienceThis paper aims to compare the recent rainfall variability during the soybean cultivation month between 1998-1999 and 2012-2013 in two main producing regions in Brazil: the northwestern Rio Grande do Sul and north Mato Grosso. The data correspond to cumulative monthly figures between October and April of the National Water Agency rain gauge network (ANA) in Brazil. The main results indicate annual variability different modes, especially in subtropical and temperate climates such as Rio Grande do Sul that have the observed rainfall lowest variability values indicating greater consistency between data and also a great relationship with soy annual data. In the Mato Grosso region, dominated by the tropical continental climate and also transitional climate, the variability is lower and the relation between annual rainfall and soybean production cannot be stated as simply.Le but de cet article est de comparer la variation récente de l'ensemble des précipitations des mois correspondant à la culture de soja entre 1998-1999 et 2012-2013 dans deux régions productrices au Brésil : le Nord-Ouest du Rio Grande do Sul et le Nord du Mato Grosso. Les données utilisées sont les totaux mensuels cumulés entre octobre et avril, obtenus auprès de l'Agence nationale de l'eau (ANA) du Brésil. Les principaux résultats indiquent différents modes de variabilité interannuelle, en particulier pour les climats subtropicaux et tempérés comme dans l'Etat de Rio Grande do Sul, qui présente la plus faible variabilité pluviométrique observée, ainsi qu'une bonne relation entre les pluies annuelles et les rendements de soja. Dans la région du Mato Grosso, où domine un climat tropical de type continental plus arrosé, la variabilité est moins homogène entre les stations pluviométriques et la relation entre pluies annuelles et rendements du soja ne peut être établie

    Study of timing characteristics of a 3 m long plastic scintillator counter using waveform digitizers

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    A plastic scintillator bar with dimensions 300 cm x 2.5 cm x 11 cm was exposed to a focused muon beam to study its light yield and timing characteristics as a function of position and angle of incidence. The scintillating light was read out at both ends by photomultiplier tubes whose pulse shapes were recorded by waveform digitizers. Results obtained with the WAVECATCHER and SAMPIC digitizers are analyzed and compared. A discussion of the various factors affecting the timing resolution is presented. Prospects for applications of plastic scintillator technology in large-scale particle physics detectors with timing resolution around 100 ps are provided in light of the results

    The Mid-Infrared Instrument for the James Webb Space Telescope, III: MIRIM, The MIRI Imager

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    In this article, we describe the MIRI Imager module (MIRIM), which provides broad-band imaging in the 5 - 27 microns wavelength range for the James Webb Space Telescope. The imager has a 0"11 pixel scale and a total unobstructed view of 74"x113". The remainder of its nominal 113"x113" field is occupied by the coronagraphs and the low resolution spectrometer. We present the instrument optical and mechanical design. We show that the test data, as measured during the test campaigns undertaken at CEA-Saclay, at the Rutherford Appleton Laboratory, and at the NASA Goddard Space Flight Center, indicate that the instrument complies with its design requirements and goals. We also discuss the operational requirements (multiple dithers and exposures) needed for optimal scientific utilization of the MIRIM.Comment: 29 pages, 9 figure

    Sister Mary Joseph's Nodule at a University Teaching Hospital in Northwestern Tanzania: A Retrospective Review of 34 cases.

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    Sister Mary Joseph's nodule is a metastatic tumor deposit in the umbilicus and often represents advanced intra-abdominal malignancy with dismal prognosis. There is a paucity of published data on this subject in our setting. This study was conducted to describe the clinicopathological presentation and treatment outcome of this condition in our environment and highlight challenges associated with the care of these patients, and to proffer solutions for improved outcome. This was a retrospective study of histologically confirmed cases of Sister Mary Joseph's nodule seen at Bugando Medical Centre between March 2003 and February 2013. Data collected were analyzed using descriptive statistics. A total of 34 patients were enrolled in the study. Males outnumbered females by a ratio of 1.4:1. The vast majority of patients (70.6%) presented with large umbilical nodule > 2 cm in size. The stomach (41.1%) was the most common location of the primary tumor. Adenocarcinoma (88.2%) was the most frequent histopathological type. Most of the primary tumors (52.9%) were poorly differentiated. As the disease was advanced and metastatic in all patients, only palliative therapy was offered. Out of 34 patients, 11 patients died in the hospital giving a mortality rate of 32.4%. Patients were followed up for 24 months. At the end of the follow-up period, 14(60.9%) patients were lost to follow-up and the remaining 9 (39.1%) patients died. Patients survived for a median period of 28 weeks (range, 2 to 64 weeks). The nodule recurred in 6 (26.1%) patients after complete excision. Sister Mary Joseph's nodule of the umbilicus is not rare in our environment and often represents manifestation of a variety of advanced intra-abdominal malignancies. The majority of the patients present at a late stage and many with distant metastases. The patient's survival is very short leading to a poor outcome. Early detection of primary cancer at an early stage may improve the prognosis

    Methodological enhancements in MDO process investigated in the AGILE European project

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    This paper presents methodological investigations performed in research activities in the field of MDO in overall aircraft design in the ongoing EU funded research project AGILE. AGILE is developing the next generation of aircraft Multidisciplinary Design and Optimization processes, which target significant reductions in aircraft development costs and time to market, leading to cheaper and greener aircraft solutions. The paper introduces the AGILE project structure and describes the achievements of the 1st year (Design Campaign 1) leading to a reference distributed MDO system. A focus is then made on the different novel optimization techniques studied during the 2nd year, all willing to ease the optimization of complex work flows, characterized by high degree of discipline interdependencies, high number of design variables in the context of multi-level and multi-partner collaborative engineering projects. Then the implementation of these methods in the enhanced MDO framework is discussed

    An extensive spectroscopic time-series of three Wolf-Rayet stars. I. The lifetime of large-scale structures in the wind of WR 134

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    During the summer of 2013, a 4-month spectroscopic campaign took place to observe the variabilities in three Wolf-Rayet stars. The spectroscopic data have been analyzed for WR 134 (WN6b), to better understand its behaviour and long-term periodicity, which we interpret as arising from corotating interaction regions (CIRs) in the wind. By analyzing the variability of the He II λ\lambda5411 emission line, the previously identified period was refined to P = 2.255 ±\pm 0.008 (s.d.) days. The coherency time of the variability, which we associate with the lifetime of the CIRs in the wind, was deduced to be 40 ±\pm 6 days, or \sim 18 cycles, by cross-correlating the variability patterns as a function of time. When comparing the phased observational grayscale difference images with theoretical grayscales previously calculated from models including CIRs in an optically thin stellar wind, we find that two CIRs were likely present. A separation in longitude of Δϕ\Delta \phi \simeq 90^{\circ} was determined between the two CIRs and we suggest that the different maximum velocities that they reach indicate that they emerge from different latitudes. We have also been able to detect observational signatures of the CIRs in other spectral lines (C IV λλ\lambda\lambda5802,5812 and He I λ\lambda5876). Furthermore, a DAC was found to be present simultaneously with the CIR signatures detected in the He I λ\lambda5876 emission line which is consistent with the proposed geometry of the large-scale structures in the wind. Small-scale structures also show a presence in the wind, simultaneously with the larger scale structures, showing that they do in fact co-exist.Comment: 13 pages, 13 figures, 4 tables, will appear in the Monthly Notices for the Royal Astronomical Society, http://www.astro.umontreal.ca/~emily/CIR_Lifetime_WR134_full.pd
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