917 resultados para complex nonlinear least squares
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Pós-graduação em Ciência Animal - FMVA
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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Mapping of clay, iron oxide and adsorbed phosphate in Oxisols using diffuse reflectance spectroscopy
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Ciências Ambientais - Sorocaba
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Freshwater copepods were sampled in the La Plata River basin to identify the processes that affect beta diversity and to determine the main factors influencing their geographical distribution and patterns of endemism. Beta diversity patterns exhibited strong dissimilarity between locations; the turnover process was predominant and indicated a replacement of species along the basin. Redundancy analysis indicated the presence of two large sets of species separated geographically by a boundary zone, with several associated variables. Northern species were associated with water transparency and temperature, mean air temperature, mean air temperature during winter and minimum air temperature of coldest month, indicating that these species are not tolerant to low temperatures and are abundant in reservoirs that are common in the upper stretch of the Paraná River basin. Southern species were related with amplitude of air temperature, turbidity, total phosphorus and total suspended matter, indicating that these species are polythermic and have adapted to live in river stretches. From 20 environmental variables analyzed in our study, partial least squares analysis indicated four variables with increased retention of effects on copepod abundance: air temperature, minimum temperature of coldest month, turbidity and transparency. Because almost all of the species found in this study occurred across a wide range of habitat types, the cause of the separation between river and reservoir species could be considered to be more anthropogenic than natural, and it primarily affected species abundance. For certain members of the northern group of copepod species, distribution was dependent on high temperatures, whereas the distribution of the southern group indicated that the species were polythermic.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The torsional stiffness of chassis is one of the most important properties of a vehicle's structure and therefore its measurement is important. For the first time, the torsional stiffness was considered on the design of a prototype Baja SAE of the team from UNESP - FEG, Equipe Piratas do Vale Bardahl. According to the team's opinion, the increase of stiffness on this prototype, called MB1114, made possible a great improvement in its performance during competitions. In this work, the experimental evaluation of the torsional stiffness from this prototype is performed, detailing the analysis of results, as well as, the hysteresis' effect, least-squares regression and uncertainty analysis. It also shows that it is possible to measure the torsional stiffness of chassis with a low experimental uncertainty without expending many resources. The test rig costed R$ 32,50 due the reuse of materials and the use of instrumentation already available on campus. Furthermore, it is simple to produce and can be easily stocked. Those features are important for Baja and Formula SAE teams. Lastly, the measured value is used to validate the finite element analysis performed by the team during this prototype's design, because similar studies will be performed for the new cars. After investigating the finite element analysis, one result 13,5% higher than the measured value was reached. This difference is believed to be occurred due the imperfections of the finite element model, in other words, for not been possible to simulate every phenomena present on the real model
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The coyote (Canis latrans) is among the most studied animals in North America. Because of its adaptability and success as a predator, the coyote has flourished and is still expanding its range. Coyotes can now be found throughout most of North America and south into Central America (Voight and Berg 1987). Studies in recent years have been extensive to understand the interrelationships of prey and coyotes (Shelton and Klindt 1974, Beckoff and Wells 1981), as well as demographic relationships (Davis et al. 1975, Knowlton and Stoddart 1978, Mitchell 1979, Bowen 1981) and feeding strategies (Todd and Keith 1976, Andelt et al. 1987, MacCracken and Hansen 1987, Gese et al. 1988a). With the advance of radio telemetry, researchers have investigated lifestyle characteristics spatially with home ranges or temporally with movements in relation to habitat requirements. Researchers have studied home ranges of coyotes in various regions of the United States (Livaitis and Shaw 1980, Andelt 1981, Springer 1982, Pyrah 1984, Gese et al. 1988a) and Canada (Bowen 1982). Some studies of home range were separated by season (Ozoga and Harger 1966) or relation to nearby food sources (Danner and Smith 1980). Home range analysis in relation to social interactions of coyotes has been either neglected, overlooked, or avoided. Gese et al. (1988a) recognized a transient class of coyote by home range size. Coyote social systems are very complex and can vary by season or locality in addition to some reports of group or pack systems (Hamlin and Schweitzer 1979, Beckoff and Wells 1981, Bowen 1981, Gese et al. 1988b). Coyotes maintain communication with conspecifics through vocal and olfactory signals (Lehner 1987, Bowen and McTaggert Cowan 1980). Social interactions may be by far the most complex and least understood aspect related to coyote ecology. Coyote movements can be related to many factors including food, water, cover, and social interactions. Movements in relation to food sources are well documented (Fitch 1948, Todd and Keith 1976, Danner and Smith 1980) although reports on movements in relation to water have not been reported, probably because of limited research in desert situations. There has been some mention of coyotes' movements in relation to cover (Wells and Beckoff 1982). The objectives of this study were to delineate annual and seasonal home ranges, movements, and habitat use of coyotes in the northern Chihuahuan desert.
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The torsional stiffness of chassis is one of the most important properties of a vehicle's structure and therefore its measurement is important. For the first time, the torsional stiffness was considered on the design of a prototype Baja SAE of the team from UNESP - FEG, Equipe Piratas do Vale Bardahl. According to the team's opinion, the increase of stiffness on this prototype, called MB1114, made possible a great improvement in its performance during competitions. In this work, the experimental evaluation of the torsional stiffness from this prototype is performed, detailing the analysis of results, as well as, the hysteresis' effect, least-squares regression and uncertainty analysis. It also shows that it is possible to measure the torsional stiffness of chassis with a low experimental uncertainty without expending many resources. The test rig costed R$ 32,50 due the reuse of materials and the use of instrumentation already available on campus. Furthermore, it is simple to produce and can be easily stocked. Those features are important for Baja and Formula SAE teams. Lastly, the measured value is used to validate the finite element analysis performed by the team during this prototype's design, because similar studies will be performed for the new cars. After investigating the finite element analysis, one result 13,5% higher than the measured value was reached. This difference is believed to be occurred due the imperfections of the finite element model, in other words, for not been possible to simulate every phenomena present on the real model
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We report cross sections for elastic electron scattering by gas phase glycine (neutral form), obtained with the Schwinger multichannel method. The present results are the first obtained with a new implementation that combines parallelization with OpenMP directives and pseudopotentials. The position of the well known pi* shape resonance ranged from 2.3 eV to 2.8 eV depending on the polarization model and conformer. For the most stable isomer, the present result (2.4 eV) is in fair agreement with electron transmission spectroscopy assignments (1.93 +/- 0.05 eV) and available calculations. Our results also point out a shape resonance around 9.5 eV in the A' symmetry that would be weakly coupled to vibrations of the hydroxyl group. Since electron attachment to a broad and lower lying sigma* orbital located on the OH bond has been suggested the underlying mechanism leading to dissociative electron attachment at low energies, we sought for a shape resonance around similar to 4 eV. Though we obtained cross sections with the target molecule at the equilibrium geometry and with stretched OH bond lengths, least-squares fits to the calculated eigenphase sums did not point out signatures of this anion state (though, in principle, it could be hidden in the large background). The low energy (similar to 1 eV) integral cross section strongly scales as the bond length is stretched, and this could indicate a virtual state pole, since dipole supported bound states are not expected at the geometries addressed here. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3687345]
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The determination of hydrodynamic coefficients of full scale underwater vehicles using system identification (SI) is an extremely powerful technique. The procedure is based on experimental runs and on the analysis of on-board sensors and thrusters signals. The technique is cost effective and it has high repeatability; however, for open-frame underwater vehicles, it lacks accuracy due to the sensors' noise and the poor modeling of thruster-hull and thruster-thruster interaction effects. In this work, forced oscillation tests were undertaken with a full scale open-frame underwater vehicle. These conducted tests are unique in the sense that there are not many examples in the literature taking advantage of a PMM installation for testing a prototype and; consequently, allowing the comparison between the experimental results and the ones estimated by parameter identification. The Morison's equation inertia and drag coefficients were estimated with two parameter identification methods, that is, the weighted and the ordinary least-squares procedures. It was verified that the in-line force estimated from Morison's equation agrees well with the measured one except in the region around the motion inversion points. On the other hand, the error analysis showed that the ordinary least-squares provided better accuracy and, therefore, was used to evaluate the ratio between inertia and drag forces for a range of Keulegan-Carpenter and Reynolds numbers. It was concluded that, although both experimental and estimation techniques proved to be powerful tools for evaluation of an open-frame underwater vehicle's hydrodynamic coefficients, the research provided a rich amount of reference data for comparison with reduced models as well as for dynamic motion simulation of ROVs. [DOI: 10.1115/1.4004952]