7,549 research outputs found

    Food consumption of Rhammatocerus schistocercoides Rehn (Orthoptera: Acrididae) infected by the fungus Metarhizium flavoviride Gams & Rozsypal.

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    Made available in DSpace on 2018-06-11T19:01:59Z (GMT). No. of bitstreams: 1 ID25630.pdf: 802298 bytes, checksum: c6ff3635c18289c1e47d0d8817abacb4 (MD5) Previous issue date: 2005-09-26bitstream/item/178447/1/ID-25630.pd

    Semiclassical Evolution of Dissipative Markovian Systems

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    A semiclassical approximation for an evolving density operator, driven by a "closed" hamiltonian operator and "open" markovian Lindblad operators, is obtained. The theory is based on the chord function, i.e. the Fourier transform of the Wigner function. It reduces to an exact solution of the Lindblad master equation if the hamiltonian operator is a quadratic function and the Lindblad operators are linear functions of positions and momenta. Initially, the semiclassical formulae for the case of hermitian Lindblad operators are reinterpreted in terms of a (real) double phase space, generated by an appropriate classical double Hamiltonian. An extra "open" term is added to the double Hamiltonian by the non-hermitian part of the Lindblad operators in the general case of dissipative markovian evolution. The particular case of generic hamiltonian operators, but linear dissipative Lindblad operators, is studied in more detail. A Liouville-type equivariance still holds for the corresponding classical evolution in double phase, but the centre subspace, which supports the Wigner function, is compressed, along with expansion of its conjugate subspace, which supports the chord function. Decoherence narrows the relevant region of double phase space to the neighborhood of a caustic for both the Wigner function and the chord function. This difficulty is avoided by a propagator in a mixed representation, so that a further "small-chord" approximation leads to a simple generalization of the quadratic theory for evolving Wigner functions.Comment: 33 pages - accepted to J. Phys.

    On the Infrared Behavior of the Pressure in Thermal Field Theories

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    We study non-perturbatively, via the Schwinger-Dyson equations, the leading infrared behavior of the pressure in the ladder approximation. This problem is discussed firstly in the context of a thermal scalar field theory, and the analysis is then extended to the Yang-Mills theory at high temperatures. Using the Feynman gauge, we find a system of two coupled integral equations for the gluon and ghost self-energies, which is solved analytically. The solutions of these equations show that the contributions to the pressure, when calculated in the ladder approximation, are finite in the infrared domain.Comment: 20 pages plus 4 figures available by request, IFUSP/P-100

    Factors controlling spatio-temporal variation in carbon dioxide efflux from surface litter, roots, and soil organic matter at four rain forest sites in the eastern Amazon

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    [1] This study explored biotic and abiotic causes for spatio-temporal variation in soil respiration from surface litter, roots, and soil organic matter over one year at four rain forest sites with different vegetation structures and soil types in the eastern Amazon, Brazil. Estimated mean annual soil respiration varied between 13-17 t C ha(-1) yr(-1), which was partitioned into 0-2 t C ha(-1) yr(-1) from litter, 6-9 t C ha(-1) yr(-1) from roots, and 5-6 t C ha(-1) yr(-1) from soil organic matter. Litter contribution showed no clear seasonal change, though experimental precipitation exclusion over a one-hectare area was associated with a ten-fold reduction in litter respiration relative to unmodified sites. The estimated mean contribution of soil organic matter respiration fell from 49% during the wet season to 32% in the dry season, while root respiration contribution increased from 42% in the wet season to 61% during the dry season. Spatial variation in respiration from soil, litter, roots, and soil organic matter was not explained by volumetric soil moisture or temperature. Instead, spatial heterogeneity in litter and root mass accounted for 44% of observed spatial variation in soil respiration (p < 0.001). In particular, variation in litter respiration per unit mass and root mass accounted for much of the observed variation in respiration from litter and roots, respectively, and hence total soil respiration. This information about patterns of, and underlying controls on, respiration from different soil components should assist attempts to accurately model soil carbon dioxide fluxes over space and time

    Selection index via REML/BLUP for identifying superior banana genotypes in the central region of Goiás state, Brazil.

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    EN-US: This study had the aim of evaluating 15 agronomic characters of 23 banana genotypes of the Cavendish, Prata, Prata-Anã, Pacovan, Mysore and Maçã groups, in three production cycles, in the climatic conditions of the central region of Goiás state, Brazil, identifying superior cultivars. The treatments were arranged in a completely randomized design, with replicates varying from 3 to 18 clones according to the availability of seedlings. Because of the unbalanced data, the components of variance were estimated using the mixed model methodology. In order to identify the superior genotypes, the predicted mean genotypic values were taken into account. The FHIA-02 (Cavendish group), PA42-44 (Prata Anã group) and FHIA-18 (Prata Anã group) genotypes presented the highest flowering precocity. The Bucanero, FHIA-17 (Cavendish group) and Grande Naine genotypes were the most productive. The Grande Naine, FHIA-17 and FHIA-02 genotypes presented the lowest sizes, and the FHIA-17, Bucanero and PV79-34 (Hybrid Pacovan) genotypes the largest pseudo stems circumferences. The genotypes with the lowest mortality rates were the Pacovan, Garantida (group Prata) and Calipso. Based on the multi-trait selection index, it was concluded that the FHIA-17, Grande Naine, Bucanero, and FHIA-02 genotypes were the most promising cultivars for production in the central region of Goiás due to their agronomic characters and high yield. | PT-BR: Este trabalho teve como objetivo avaliar 15 caracteres agronômicos de 23 genótipos de bananeira dos grupos Cavendish, Prata, Prata-Anã, Pacovan, Mysore e Maçã, em três ciclos de produção, nas condições climáticas da região central de Goiás, Brasil, a fim de identificar os melhores cultivares para essa região. Os tratamentos foram dispostos em delineamento inteiramente casualizado, com repetições variando de 3 a 18 clones de acordo com a disponibilidade de mudas. Por se tratar de dados desbalanceados os componentes de variância foram estimados utilizando a metodologia de modelos mistos. Com o intuito de identificar os genótipos superiores foi levado em consideração os valores genotípicos médios preditos. Os genótipos FHIA-02 (grupo Cavendish), PA42-44 (grupo Prata Anã) e FHIA-18 (grupo Prata Anã), apresentaram maior precocidade de floração. Os genótipos Bucanero, FHIA-17 (grupo Cavendish) e Grande Naine foram os mais produtivos. Os genótipos Grande Naine, FHIA-17 e FHIA-02 apresentam os menores portes e os genótipos FHIA-17, Bucanero e PV79-34 (híbrido de Pacovan) as maiores circunferências do pseudocaule. Os genótipos com as menores taxas de mortalidade foram Pacovan, Garantida (grupo Prata) e Calipso. Com base no índice de seleção, conclui-se que os genótipos FHIA-17, Grande Naine, Bucanero e FHIA-02 foram os mais promissores para serem produzidos na região central de Goiás, por apresentarem alta produtividade e caracteres agronômicos demandados pelos produtores

    Organomineral phosphorus fertilization in the production of corn, soybean and bean cultivated in succession.

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    The use of organic waste in agriculture has been used aiming at greater productivity, decrease in the cost of production and sustainable use of resources. The present study aimed at evaluating the effect of phosphate fertilization with the maintenance of organomineral fertilizers, combining poultry manure and soluble or reactive phosphate, in the production of grains in corn culture and the residual effect for subsequent crops of beans and soybeans. The experiment was conducted in Sete Lagoas, MG, in 2015, using three fertilizers with sources of different phosphorus sources (triple super phosphate?STP, organomineral with STP and organomineral with Bayovar phosphate) applied at the doses of 65, 130, 195 and 260 kg&#8729;ha&#8722;1 of P2O5 total, and compared to the control without phosphate fertilization. We evaluated the contents of foliar P, P accumulation in the grains, yields of corn grains, beans and soy, accumulated productivity and export of accumulated P of the three cultures. The three cultures assessed presented higher productivity when compared to the average of the factorial treatments that received phosphate fertilization relative to the control. Organomineral fertilizers increased grain production, obtaining average productivity equal to or greater than those obtained with the exclusive use of STP

    Silvicultura na Amazônia brasileira: avaliação de experiências e recomendações para implementação e melhoria dos sistemas.

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    Levantamento de dados secundários. Dados gerais das propriedades. Assistência técnica nas experiências silviculturais. Fatores que levaram à implementação/manejo de experiências silviculturais. Acesso a financiamento para as experiências silviculturais. Fatores que dificultam a implentação de experiências silviculturais. Fatores que afetam a manutenção de experiências silviculturais. Fatores que determinam o prosseguimento nas experiências silviculturais.bitstream/item/84873/1/SILVICULTURABrasileira.pd
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