116 resultados para holomorphic fourth-R function


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The dissociation dynamics of heteronuclear diatomic molecules induced by infrared laser pulses is investigated within the framework of the classical driven Morse oscillator. The interaction between the molecule and the laser field described in the dipole formulation is given by the product of a time-dependent external field with a position-dependent permanent dipole function. The effects of changing the spatial range of the dipole function in the classical dissociation dynamics of large ensembles of trajectories are studied. Numerical calculations have been performed for distinct amplitudes and carrier frequencies of the external pulses and also for ensembles with different initial energies. It is found that there exist a set of values of the dipole range for which the dissociation probability can be completely suppressed. The dependence of the dissociation on the dipole range is explained through the examination of the Fourier series coefficients of the dipole function in the angle variable of the free system. In particular, the suppression of dissociation corresponds to dipole ranges for which the Fourier coefficients associated with nonlinear resonances are null and the chaotic region in the phase space is reduced to thin layers. In this context, it is shown that the suppression of dissociation of heteronuclear molecules for certain frequencies of the external field is a consequence of the finite range of the corresponding permanent dipole. © 2013 American Physical Society.

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Artificial Neural Networks are widely used in various applications in engineering, as such solutions of nonlinear problems. The implementation of this technique in reconfigurable devices is a great challenge to researchers by several factors, such as floating point precision, nonlinear activation function, performance and area used in FPGA. The contribution of this work is the approximation of a nonlinear function used in ANN, the popular hyperbolic tangent activation function. The system architecture is composed of several scenarios that provide a tradeoff of performance, precision and area used in FPGA. The results are compared in different scenarios and with current literature on error analysis, area and system performance. © 2013 IEEE.

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Vegetable oils are used in the industry of processed food, including deep-fat frying. This work determined data on the thermophysical properties of cotton, canola, sunflower, corn, and soybean oils. Thermal conductivity, heat capacity, density, and viscosity were measured within the temperature range of 299.15-433.15 K. The data showed that the temperature influenced the thermophysical properties of the oils studied. The developed correlations could be used to predict these properties within the range of temperatures studied. © 2013 Copyright Taylor and Francis Group, LLC.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Among the herbicides recommended for the dry season and registered to sugarcane crop, amicarbazone, isoxaflutole and the association diuron + hexazinone + sulfomethuron-methyl can be highlighted. These are pre-emergence herbicides efficient against broad-leaved weeds. Morning glory causes large losses in infested sugarcane fields by bending the stalks and interfering in harvesting. In this study the effectiveness of pre-emergence herbicides for two species of morning glory (Ipomoea hederifolia and Ipomoea grandifolia) was evaluated. Treatments were arranged in completely randomized factorial design (4 x 7). There were four periods of water restriction (0, 30, 60 and 90 days), seven chemical treatments [diuron + hexazinone + sulfometuron-methyl (1387 + 391 + 33.35 g a.i. ha-1), diuron + hexazinone + sulfometuron-methyl (1507.5 + 425 + 36.25 g a.i. ha-1), diuron + hexazinone + sulfometuron-methyl (1658.25 + 467.5 + 39.87 g a.i. ha-1), diuron + hexazinone + sulfometuron­methyl (1809 + 510 + 43.5 g a.i. ha-1), amicarbazone (1190 g a.i. ha-1), amicarbazone + isoxaflutole (840 + 82.5 g a.i. ha-1)] and a control with no application. At 7, 14, 21 and 28 days after the restoration of moisture, control was visually evaluated. After the final evaluation, the dry mass of morning glories was measured. At 90 days of water restriction, diuron + hexazinone + sulfometuron-methyl was more effective to control I. hederifolia than the amicarbazone + isoxaflutole tank mixture. The four diuron + hexazinone + sulfometuron­methyl doses have reduced morning glory dry mass to zero; whereas treatments with amicarbazone have not. The most effective treatment for morning glory control was diuron + hexazinone + sulfometuron-methyl. This result may be due to a possible synergistic interaction.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Cardiopulmonary bypass (CPB) is often associated with renal dysfunction, as measured by plasma creatinine levels and hemodialysis rates. Aim. To compare creatinine clearance (CrCl), estimated with the Cockroft and Gault formula, between patients undergoing off-pump coronary artery bypass grafting (OPCAB) versus on-pump CABG (on-CAB). Material and methods. Between April 2008 and April 2009, 119 patients underwent coronary bypass graft surgery. Fifty-eight (58) of these patients underwent OPCAB while 61 had on-CAB. Creatinine clearance, plasma creatinine levels, and clinical outcome were compared between the groups. A creatinine clearance value of 50 mL/minute was accepted as the lowest limit of normal renal function. Results. There were two hospital deaths caused by sepses after pulmonary infection. Creatinine clearance (Preoperative OPCAB 73,64±33,72 x on-CAB 75,70±34,30mL/min; discharge OPCAB 75,73±35,07 x on-CAB 79,07±34,71 mL/ min; p=0,609), and creatinine levels (Preoperative OPCAB 1,04±0,38 x on-CAB 1,13±0,53 mg/dL; discharge OPCAB 1,12±0,79 x on-CAB 1,04±0,29mg/dL; p=0,407) did not show statistically inter-group differences. Conclusion. Deterioration in renal function is associated with higher rates of postoperative complications. No significant difference in CrCl could be demonstrated between the groups.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)