22,379 research outputs found

    Características físicas e químicas do látex e crescimento da seringueira em função da calagem e da adubação NPK em dois sistemas de explotação.

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    Objetivou-se com este estudo avaliar o efeito da calagem e da adubação NPK sobre o crescimento e as características físicas e químicas do látex de seringueiras, com 16 anos de campo, cultivadas no Planalto Ocidental Paulista

    Evidence of non-thermal X-ray emission from HH 80

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    Protostellar jets appear at all stages of star formation when the accretion process is still at work. Jets travel at velocities of hundreds of km/s, creating strong shocks when interacting with interstellar medium. Several cases of jets have been detected in X-rays, typically showing soft emission. For the first time, we report evidence of hard X-ray emission possibly related to non-thermal processes not explained by previous models of the post-shock emission predicted in the jet/ambient interaction scenario. HH 80 is located at the south head of the jet associated to the massive protostar IRAS 18162-2048. It shows soft and hard X-ray emission in regions that are spatially separated, with the soft X-ray emission region situated behind the region of hard X-ray emission. We propose a scenario for HH 80 where soft X-ray emission is associated to thermal processes from the interaction of the jet with denser ambient matter and the hard X-ray emission is produced by synchrotron radiation at the front shock.Comment: Accepted for publication in ApJ

    Nematóide do anel vermelho do coqueiro e medidas de manejo.

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    bitstream/CPATSA-2010/42061/1/INT88.pd

    A burst with double radio spectrum observed up to 212 GHz

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    We study a solar flare that occurred on September 10, 2002, in active region NOAA 10105 starting around 14:52 UT and lasting approximately 5 minutes in the radio range. The event was classified as M2.9 in X-rays and 1N in H\alpha. Solar Submillimeter Telescope observations, in addition to microwave data give us a good spectral coverage between 1.415 and 212 GHz. We combine these data with ultraviolet images, hard and soft X-rays observations and full-disk magnetograms. Images obtained from Ramaty High Energy Solar Spectroscopic Imaging data are used to identify the locations of X-ray sources at different energies and to determine the X-ray spectrum, while ultra violet images allow us to characterize the coronal flaring region. The magnetic field evolution of the active region is analyzed using Michelson Doppler Imager magnetograms. The burst is detected at all available radio-frequencies. X-ray images (between 12 keV and 300 keV) reveal two compact sources and 212 GHz data, used to estimate the radio source position, show a single compact source displaced by 25" from one of the hard X-ray footpoints. We model the radio spectra using two homogeneous sources, and combine this analysis with that of hard X-rays to understand the dynamics of the particles. Relativistic particles, observed at radio wavelengths above 50 GHz, have an electron index evolving with the typical soft-hard-soft behaviour.Comment: Submitted to Solar Physics, 20 pages, 8 fugure

    Edge phonons in black phosphorus

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    Exfoliated black phosphorus has recently emerged as a new two-dimensional crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have potentially important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and the behavior of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.Comment: 15 pages, 4 figure

    Trichospilus diatraeae (Hymenoptera: eulophidae): a potential biological control agent of Lepidopteran pests of oil palm in the brazilian Amazon.

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    A expansão da monocultura da palma do óleo (Elaeis guineensis) pode favorecer pragas como as lagartas Opsiphanes invirae Hübner, Brassolis sophorae L. (Lepidoptera: Nymphalidae) e Eupalamides cyparissias (Fabricius) (Lepidoptera: Castniidae). O objetivo foi avaliar o potencial de Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) como parasitóide de pupas de lepidópteras-praga da palma do óleo. Cinquenta fêmeas de T. diatraeae foram mantidas um tubo de ensaio por 48 horas com uma pupa dos seguintes hospedeiros: O. invirae, B. sophorae ou E. cyparissias, com, até, dois dias de idade. Trichospilus diatraeae realizou o parasitismo nas três espécies de Lepidoptera, mas obteve potencial reprodutivo em pupas de O. invirae e B. sophorae. Isto sugere que este parasitoide, de hábito polífago, pode representar uma alternativa para o controle de pragas de lepidópteros da palma de óleo na Amazônia brasileir

    Ocorrência de giberela nos genótipos de trigo do ensaio de VCU da Embrapa - ano 2012.

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    Editores técnicos: Joseani Mesquita Antunes, Ana Lídia Variani Bonato, Márcia Barrocas Moreira Pimentel
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