809 research outputs found

    Ridgelet-type Frame Decompositions for Sobolev Spaces related to Linear Transport

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    In this paper we study stability properties of ridgelet and curvelet frames for mixed-smoothness Sobolev spaces with norm ∥f∥s=∥f∥L2(Rd)+∥s⋅∇f∥L2(Rd)\|f\|_{s} = \|f\|_{L_{2}(\mathbb{R}^{d})} +\|s\cdot\nabla f\|_{L_{2}(\mathbb{R}^{d})} . Here s∈Sd−1s \in\mathbb{S}^{d-1} is a transport direction and ∇ denotes the gradient of f. Such spaces arise as domains of linear, first order transport equations. The main result of this paper is that ridgelet frames are stable in ∥⋅∥ s regardless of s, while curvelet frames are not. To show the second statement we explicitly construct functions f,g whose curvelet coefficients have all the same modulus but ∥f∥ s <∞ and ∥g∥ s =

    Optimal a priori discretization error bounds for geodesic finite elements

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    We prove optimal bounds for the discretization error of geodesic finite elements for variational partial differential equations for functions that map into a nonlinear space. For this, we first generalize the well-known Céa lemma to nonlinear function spaces. In a second step, we prove optimal interpolation error estimates for pointwise interpolation by geodesic finite elements of arbitrary order. These two results are both of independent interest. Together they yield optimal a priori error estimates for a large class of manifold-valued variational problems. We measure the discretization error both intrinsically using an H1-type Finsler norm and with the H1-norm using embeddings of the codomain in a linear space. To measure the regularity of the solution, we propose a nonstandard smoothness descriptor for manifold-valued functions, which bounds additional terms not captured by Sobolev norms. As an application, we obtain optimal a priori error estimates for discretizations of smooth harmonic maps using geodesic finite elements, yielding the first high-order scheme for this problem

    Viticultor: pensando em comprar mudas de videira? procure os viveiristas licenciados da Embrapa. Ciclo 2014-2019.

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    Alok-Imaging and -Reconstruction of Surface Defects on Heavy Plates with E.M.A.-Rayleigh Wave Transducers

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    High quality heavy plates have to be free of any defects. The UT-inspection for internal defects is introduced as a standard. However, until now the inspection for surface defects is limited to visual inspection, magnetic stray flux — or eddy current inspection. The most sensitive technique is the magnetic stray-flux technique, but it is very time consuming because of the necessity to scan the whole surface. Using Rayleigh waves the inspection can be automated and performed at rolling speed. The sensitivity of frequency optimized Rayleigh waves is sufficient to detect a 0.3 mm deep model defect at a distance of 300 mm. The use of piezoelectric probes is limited by coupling problems. These problems are overcome by the use of EMAT’s, which have been optimized with respect to probe size, sensitivity and wear resistance. For the automated inspection the ALOK-system has been adapted in a laboratory system to the surface inspection of heavy plates by Rayleigh waves. This equipment consists of an ultrasonic hardware device for fast data-acquisition and -preprocessing (essential data reduction) according to the ALOK-algorithm, and a computer to realize noise- and ghost — elimination as well as defect imaging and -reconstruction

    Differences in daptomycin and vancomycin ex vivo behaviour can lead to false interpretation of negative blood cultures

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    AbstractIn clinical studies on bacteraemia, the negativity of blood cultures is an important endpoint for comparing the efficacy of different therapeutic regimens. In FAN° anaerobic blood culture medium (BacT/ALERT system), daptomycin displayed increased MIC against Staphylococcus aureus and improved abolishment of its carryover effect in charcoal when compared with vancomycin. Differences between these two drugs can lead to a false interpretation of negative blood cultures. To compare different antibiotic regimens for the treatment of bacteraemia, preliminary studies are mandatory to ensure that ex vivo antibiotic behaviour is similar in the blood-culture system used

    Prediction model for phenology of grapevine cultivars with hot water treatment.

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    The objective of this work was to prepare a prediction model for the phenology of grapevine cultivars (Bordô, Cabernet Sauvignon, Moscato Embrapa, Paulsen 1103, SO4, and IAC 572) using hot water treatment. The heat treatment with hot water consisted of combinations of three temperatures (50, 53, and 55°C) and three time periods (30, 45, and 60 min), with or without previous hydration for 30 min. After the treatments, the cuttings were planted in the field and their phenological development was evaluated during two months. The six studied cultivars presented different responses to the effects of the factors temperature and time, but did not differ significantly regarding hydration. It was possible to develop a mathematical model for the use of hot water treatment in grapevine cuttings, based on phenological development (yphenology = 48.268 - 0.811x1 - 0.058x2) and validated by the variables sprouting and root emission. From the developed model, it is recommended that the hot water treatment be applied in the temperature range between 48 and 51°C for cuttings of all cultivars. O objetivo deste trabalho foi elaborar um modelo de previsão da fenologia de cultivares de videira (Bordô, Cabernet Sauvignon, Moscato Embrapa, Paulsen 1103, SO4 e IAC 572) com uso de tratamento de água quente. O tratamento térmico com água quente consistiu de combinações de três temperaturas (50, 53 e 55°C) com três intervalos de tempo (30, 45 e 60 min), com ou sem hidratação prévia por 30 min. Após os tratamentos, as estacas foram plantadas a campo e seu desenvolvimento fenológico foi avaliado por dois meses. As seis cultivares estudadas apresentaram respostas distintas quanto à influência dos fatores temperatura e tempo, mas não diferiram significativamente quanto à hidratação. Foi possível desenvolver um modelo matemático para uso do tratamento de água quente em estacas de videira, baseado no desenvolvimento fenológico (yfenologia= 48,268 - 0,811x1 - 0,058x2) e validado com as variáveis brotação e emissão de raízes. Recomenda-se, a partir do modelo desenvolvido, que o tratamento de água quente seja aplicado na faixa de temperatura entre 48 e 51°C para estacas de todas as cultivares.Título em português: Modelo de previsão para fenologia de cultivares de videira com tratamento de água quente

    Perfil hormonal em mudas Bordô/VR043-43 pós-forçagem a partir de estacas com diferentes épocas de coleta e tempos de armazenagem.

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    Híbridos Vitis rotundifolia (ex.: VR043-43) têm sido empregados como porta-enxertos em vinhedos com problemas de estresses bióticos, principalmente no estado de Santa Catarina. Entretanto, a produção de mudas é dificultada com estacas lignificadas, pela restrição em calogênese de enxertia e enraizamento desses genótipos.CLAUDIO DE ANDRADE BARROS, CNPUV, 29742

    Qualidade de mudas de videira em pós-forçagem submetidas a aplicação de etefom, diferentes épocas de coleta e tempo de câmara fria.

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    A procura por mudas de videira com qualidade superior tem se intensificado ultimamente, exigindo aprimoramento no processo de produção pelos viveiristas. A cultivar Bordô (B) enxertada nos porta-enxertos P1103 (P) e VR043-43 (VR) são as combinações tradicionais utilizadas no Rio Grande do Sul e em Santa Catarina, respectivamente.Daniel Antunes Souza, 333734, CNPU
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