1,158 research outputs found

    Efficiency of some chemical pesticides against the fall armyworm Spodoptera frugiperda (J. E. Smith, 1797) on corn field

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    The fall armyworm is one of the most important pest on corn fields. It causes enormous losses almost every year. In order to know the effects of some chemicals against the caterpillars, a study was conducted under field conditions in Piracicaba, State of São Paulo, Brazil, durin December of 1983. Plants were sprayed (200 liters per hectare) with a twenty liter costal manual sprayer. The treatments were nine: A - check (nothing was applied). B - moncrorophos, 240 g; C - biphenthrin 10 g; D - triazophos, 200 g; E - carbamate UC 75118, 150 g; F - monocrotophos, 400 g; G - acephate, 375 g; H - carbamate UC 76724:, 150 g; I - c lofentezine, 250 g. The quantities mentioned above are of active ingredient used per hectare. Two days after the spray, the best pesticides were triazophos and biphenthrin. After 07 days no one product had a good efficiency.A lagarta do cartucho do milho é um sério depredador da cultura do milho. Quase todos os anos, os danos ocasionados às plantas são grandes. Para se conhecer o efeito de alguns defensivos sobre a citada lagarta, realizou-se este trabalho experimental, instalado em Piracicaba, SP, a 09 de dezembro de l983. Os produtos foram aplicados com pulverizador costal, manual, de 20 litros de capacidade, provido de bico em leque Teejet 8002. Utilizaram-se 200 litros de água por hectare e 30 cm³ de "Extravon" (espalhante-adesivo) por 100 litros de calda. Os tratamentos foram nove: A - testemu nha; B - monocrotofós, 240 g; C - bifentrina, 10 g; D - triazofós, 200 g; E -carbamato UC 75118, 150 g; F - monocro tofós, 400 g; G - acefato, 375 g; H - cabamato UC 76724, 150 g; I - clofentezina, 250 g. As quantidades acima são de ingrediente ativo por hectare. Aos 02 dias da pulverização, os melhores foram o triazofós e a bifentrina. Aos 07 dias, nenhum produto apresentava boa eficiência

    Highlights from the Pierre Auger Observatory

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    The Pierre Auger Observatory is the world's largest cosmic ray observatory. Our current exposure reaches nearly 40,000 km2^2 str and provides us with an unprecedented quality data set. The performance and stability of the detectors and their enhancements are described. Data analyses have led to a number of major breakthroughs. Among these we discuss the energy spectrum and the searches for large-scale anisotropies. We present analyses of our Xmax_{max} data and show how it can be interpreted in terms of mass composition. We also describe some new analyses that extract mass sensitive parameters from the 100% duty cycle SD data. A coherent interpretation of all these recent results opens new directions. The consequences regarding the cosmic ray composition and the properties of UHECR sources are briefly discussed.Comment: 9 pages, 12 figures, talk given at the 33rd International Cosmic Ray Conference, Rio de Janeiro 201

    Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

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    We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR

    The Pierre Auger Observatory III: Other Astrophysical Observations

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    Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference, Beijing, China, August 201

    Soil chemical quality in integrated production systems with the presence of native and exotic tree components in the Brazilian Eastern Amazon.

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    Conservation systems involving trees enhance the sustainability of tropical soils. However, little is known on the effect of integrated systems with native and exotic trees on soil chemical quality in the eastern Amazon

    Operations of and Future Plans for the Pierre Auger Observatory

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    Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200

    Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

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    The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E>Eth=5.5×1019E>E_{th}=5.5\times 10^{19} eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E>EthE>E_{th} are heavy nuclei with charge ZZ, the proton component of the sources should lead to excesses in the same regions at energies E/ZE/Z. We here report the lack of anisotropies in these directions at energies above Eth/ZE_{th}/Z (for illustrative values of Z=6, 13, 26Z=6,\ 13,\ 26). If the anisotropies above EthE_{th} are due to nuclei with charge ZZ, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies
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