6,465 research outputs found

    Application of two phosphorus models with different complexities in a mesoscale river catchment

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    The water balance and phosphorus inputs of surface waters of the Weiße Elster catchment, Germany, have been quantified using the models GROWA/MEPhos and SWAT. A comparison of the model results shows small differences in the mean long-term total runoff for the entire study area. All relevant pathways of phosphorus transport were considered in MEPhos with phosphorus inputs resulting to about 65% from point sources. SWAT focuses on agricultural areas and estimates a phosphorus input of about 60% through erosion. The mean annual phosphorus input from erosion calculated with SWAT is six times higher than the estimation with MEPhos due to the differing model concepts. This shows the uncertainty contributed by the modelling description of phosphorus pathways

    Frequência haplotípica de Xanthomonas axonopodis pv. phaseoliestimada por Rep-PCR.

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    O objetivo deste trabalho foi estimar a frequência haplotípica de vinte isolados de Xap oriundos de quatro regiões produtoras de feijoeiro comum no Brasil.Pôster - pós-graduação

    On kernel engineering via Paley–Wiener

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    A radial basis function approximation takes the form s(x)=k=1nakϕ(xbk),xRd,s(x)=\sum_{k=1}^na_k\phi(x-b_k),\quad x\in {\mathbb{R}}^d, where the coefficients a 1,…,a n are real numbers, the centres b 1,…,b n are distinct points in ℝ d , and the function φ:ℝ d →ℝ is radially symmetric. Such functions are highly useful in practice and enjoy many beautiful theoretical properties. In particular, much work has been devoted to the polyharmonic radial basis functions, for which φ is the fundamental solution of some iterate of the Laplacian. In this note, we consider the construction of a rotation-invariant signed (Borel) measure μ for which the convolution ψ=μ φ is a function of compact support, and when φ is polyharmonic. The novelty of this construction is its use of the Paley–Wiener theorem to identify compact support via analysis of the Fourier transform of the new kernel ψ, so providing a new form of kernel engineering

    A coleção de Pseudocercospora griseola e sua importância para a pesquisa do feijoeiro comum.

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    O objetivo deste trabalho foi à obtenção, caracterização e manutenção de novos isolados de Pseudocercospora griseola para uso no programa de melhoramento genético da Embrapa.Pôster - graduação

    Produção de grãos em relação com reação a doenças em feijoeiro comum cultivado em sistema de manejo orgânico.

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    Este trabalho objetivou avaliar a produção de grãos do feijoeiro-comum em sistema de manejo orgânico e os efeitos do crestamento bacteriano comum e da mancha angular sobre a produção do feijoeiro-comum da cultivar BRS supremo sob diferentes tipos de cultura de cobertura e manejo do solo.CONAFE

    Numerical Ricci-flat metrics on K3

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    We develop numerical algorithms for solving the Einstein equation on Calabi-Yau manifolds at arbitrary values of their complex structure and Kahler parameters. We show that Kahler geometry can be exploited for significant gains in computational efficiency. As a proof of principle, we apply our methods to a one-parameter family of K3 surfaces constructed as blow-ups of the T^4/Z_2 orbifold with many discrete symmetries. High-resolution metrics may be obtained on a time scale of days using a desktop computer. We compute various geometric and spectral quantities from our numerical metrics. Using similar resources we expect our methods to practically extend to Calabi-Yau three-folds with a high degree of discrete symmetry, although we expect the general three-fold to remain a challenge due to memory requirements.Comment: 38 pages, 10 figures; program code and animations of figures downloadable from http://schwinger.harvard.edu/~wiseman/K3/ ; v2 minor corrections, references adde

    Determination and ranking of target areas in catchments for the implementation of nitrogen reduction measures

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    International audienceThe implementation of the EU Water Framework Directive (EU-WFD) forms the background of the WAgriCo-project (Water Resources Management in Cooperation with Agriculture). WagriCo concentrates on the development of nitrogen management options adapted to hydrological and agro-economic site conditions and at demonstrating new participation approaches and technologies suitable for setting-up programmes of measures. The article outlines the conceptual model approach and its application in the pilot region "Große Aue" (Northern Germany). Furthermore the process of delineating priority areas is described, which act as spatial targets for the adaptation of regionally differentiated nutrient reduction measures

    Computing Topology Preservation of RBF Transformations for Landmark-Based Image Registration

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    In image registration, a proper transformation should be topology preserving. Especially for landmark-based image registration, if the displacement of one landmark is larger enough than those of neighbourhood landmarks, topology violation will be occurred. This paper aim to analyse the topology preservation of some Radial Basis Functions (RBFs) which are used to model deformations in image registration. Mat\'{e}rn functions are quite common in the statistic literature (see, e.g. \cite{Matern86,Stein99}). In this paper, we use them to solve the landmark-based image registration problem. We present the topology preservation properties of RBFs in one landmark and four landmarks model respectively. Numerical results of three kinds of Mat\'{e}rn transformations are compared with results of Gaussian, Wendland's, and Wu's functions
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