7,105 research outputs found

    Projeto de sistema de informação para o laboratório de microbiologia agrícola e ambiental da Embrapa Clima Temperado.

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    bitstream/item/31649/1/doc241-online.pd

    Optimal irreversible stimulated emission

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    We studied the dynamics of an initially inverted atom in a semi-infinite waveguide, in the presence of a single propagating photon. We show that atomic relaxation is enhanced by a factor of 2, leading to maximal bunching in the output field. This optimal irreversible stimulated emission is a novel phenomenon that can be observed with state-of-the-art solid-state atoms and waveguides. When the atom interacts with two one-dimensional electromagnetic environments, the preferential emission in the stimulated field can be exploited to efficiently amplify a classical or a quantum state.Comment: 9 pages, 6 figure

    Numerical investigation of the quantum fluctuations of optical fields transmitted through an atomic medium

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    We have numerically solved the Heisenberg-Langevin equations describing the propagation of quantized fields through an optically thick sample of atoms. Two orthogonal polarization components are considered for the field and the complete Zeeman sublevel structure of the atomic transition is taken into account. Quantum fluctuations of atomic operators are included through appropriate Langevin forces. We have considered an incident field in a linearly polarized coherent state (driving field) and vacuum in the perpendicular polarization and calculated the noise spectra of the amplitude and phase quadratures of the output field for two orthogonal polarizations. We analyze different configurations depending on the total angular momentum of the ground and excited atomic states. We examine the generation of squeezing for the driving field polarization component and vacuum squeezing of the orthogonal polarization. Entanglement of orthogonally polarized modes is predicted. Noise spectral features specific of (Zeeman) multi-level configurations are identified.Comment: 12 pages 9 figures. Submitted to Physical Review

    Universal optimal broadband photon cloning and entanglement creation in one dimensional atoms

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    We study an initially inverted three-level atom in the lambda configuration embedded in a waveguide, interacting with a propagating single-photon pulse. Depending on the temporal shape of the pulse, the system behaves either as an optimal universal cloning machine, or as a highly efficient deterministic source of maximally entangled photon pairs. This quantum transistor operates over a wide range of frequencies, and can be implemented with today's solid-state technologies.Comment: 5 pages, 3 figure

    Evaluating wind datasets for wave hindcasting in the NW Iberian Peninsula coast

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    The available wind datasets can be exploited to support the setup of accurate wave models, able to reproduce and forecast extreme event scenarios. It is of utmost importance in the actual context of climate change. This study focuses on evaluating the performance of a numerical wave model, using different wind datasets, helping to create a tool to assess coastal risks, and further on to support the future implementation of reliable warning systems based on numerical models. The numerical model SWAN was implemented, configured and validated for the NW Iberian Peninsula coast, as a test case region. A period of two months, from December 2013 to January 2014, was simulated due to the winter storms that crossed the area. Six distinct wind datasets were selected to test their suitability in regional wave modelling. The results were validated against several sets of wave buoy data, considering wave parameters such as significant wave height, mean wave period and peak direction. The implemented wave model configuration allowed the representation of the wave evolution with relatively good accuracy. All the wind datasets were able to produce reasonably good wave condition estimates. The dataset that best represented the wave properties varied from one wave parameter to another, but the most reliable for the selected region was the reanalysis product generated at the European Centre for Medium-Range Weather Forecasts

    Avaliação da aptidão agrícola das terras do Campo Experimental de Ouro Preto d'Oeste - Rondônia.

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    bitstream/item/61857/1/Oriental-Doc20.pd

    Seleção de porta-enxertos para maracujazeiro-amarelo nas condições da depressão cuiabana.

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    O presente trabalho foi realizado na Fazenda Experimental da Fundação Universidade Federal de Mato Grosso, com o objetivo de selecionar porta-enxertos, que apresentava maior vigor vegetativo para o maracujazeiros-amarelos, nas condições da Depressão Cuiabana. O delineamento experimental utilizado foi blocos ao acaso, sendo as épocas de avaliação consideradas como blocos (60, 75, 90, 105 e 120 dias), os tratamentos foram os porta-enxertos (seleção FB200 e a espécie Passiflora nítida), com 3 repetições. As variáveis estudadas foram o diâmetro do colo, diâmetro do tronco cerca de 1 cm acima da região enxertada, altura do colo da planta até o enxerto, altura a partir do enxerto, altura total, número de entrenós até a região enxertada, número de entrenós a partir da região enxertada e número de folhas. Os dados foram tabulados utilizando-se o pacote Statistical Package for the Social Science (SPSS) versão 11.0 e submetidos à analise estatística descritiva. Posteriormente, as variáveis foram submetidas à análise de variância multivariada com dois fatores (Manova two-way). O uso da análise de MANOVA, possibilitou observar que os porta-enxertos, o tempo e as interação entre eles tiveram grande importância na avaliação do desenvolvimento vegetativo do maracujazeiro-amarelo. A melhor resposta quanto ao desenvolvimento vegetativo foi induzido pelo porta-enxerto. O porta-enxerto ?FB200? apresentou resultados mais favoráveis quanto ao vigor de suas mudas

    Rapid yeast DNA extraction by boiling and freeze-thawing without using chemical reagents and DNA purification.

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    The purpose of this work was to study a rapid yeast DNA extraction by boiling and freeze-thawing processes without using chemical reagents or any purification procedures, to obtain a high grade PCR-product. A specific DNA fragment of the 18S region of Dekkera bruxellensis and Saccharomyces cerevisiae was chosen. The described boiling and freeze-thawing protocols generated the PCR-grade product preparations and could be used to process many samples. The amplification of the fragments could be observed after 30 and 35 cycles. These processes of extraction without using any kind of chemical reagents, especial water, and purification procedures proved to be efficient, reproducible, simple, fast, and inexpensive
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