950 resultados para Front-Tracking Method


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This letter describes a novel algorithm that is based on autoregressive decomposition and pole tracking used to recognize two patterns of speech data: normal voice and disphonic voice caused by nodules. The presented method relates the poles and the peaks of the signal spectrum which represent the periodic components of the voice. The results show that the perturbation contained in the signal is clearly depicted by pole's positions. Their variability is related to jitter and shimmer. The pole dispersion for pathological voices is about 20% higher than for normal voices, therefore, the proposed approach is a more trustworthy measure than the classical ones. © 2007.

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The present paper deals with numerical corrections factors proposed as a function of the clearness index in order to correct the diffuse solar irradiance measured with the Melo-Escobedo Shadowring Measuring Method (ME shadowring). The global irradiance was measured by an Eppley - PSP pyranometer ; direct normal irradiance by an Eppley-NIP pyrheliometer fitted to a ST-3 sun tracking device and the diffuse irradiance by an Eppley-PSP pyranometer fitted to a ME shadowring. The validations were performed by the MBE and RMSE statistical indicators. The results showed that the numerical correction factors were appropriate to correct the shadowring diffuse irradiance.

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In this paper, a trajectory tracking control problem for a nonholonomic mobile robot by the integration of a kinematic neural controller (KNC) and a torque neural controller (TNC) is proposed, where both the kinematic and dynamic models contains disturbances. The KNC is a variable structure controller (VSC) based on the sliding mode control theory (SMC), and applied to compensate the kinematic disturbances. The TNC is a inertia-based controller constituted of a dynamic neural controller (DNC) and a robust neural compensator (RNC), and applied to compensate the mobile robot dynamics, and bounded unknown disturbances. Stability analysis with basis on Lyapunov method and simulations results are provided to show the effectiveness of the proposed approach. © 2012 Springer-Verlag.

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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Among the three forms of relativistic Hamiltonian dynamics proposed by Dirac in 1949, the front form has the largest number of kinematic generators. This distinction provides useful consequences in the analysis of physical observables in hadron physics. Using the method of interpolation between the instant form and the front form, we introduce the interpolating scattering amplitude that links the corresponding time-ordered amplitudes between the two forms of dynamics and provide the physical meaning of the kinematic transformations as they allow the invariance of each individual time-ordered amplitude for an arbitrary interpolation angle. We discuss the rationale for using front form dynamics, nowadays known as light-front dynamics (LFD), and present a few explicit examples of hadron phenomenology that LFD uniquely can offer from first-principles quantum chromodynamics. In particular, model-independent constraints are provided for the analyses of deuteron form factors and the N Delta transition form factors at large momentum transfer squared Q(2). The swap of helicity amplitudes between the collinear and non-collinear kinematics is also discussed in deeply virtual Compton scattering.

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This paper aims to contribute to the three-dimensional generalization of numerical prediction of crack propagation through the formulation of finite elements with embedded discontinuities. The analysis of crack propagation in two-dimensional problems yields lines of discontinuity that can be tracked in a relatively simple way through the sequential construction of straight line segments oriented according to the direction of failure within each finite element in the solid. In three-dimensional analysis, the construction of the discontinuity path is more complex because it requires the creation of plane surfaces within each element, which must be continuous between the elements. In the method proposed by Chaves (2003) the crack is determined by solving a problem analogous to the heat conduction problem, established from local failure orientations, based on the stress state of the mechanical problem. To minimize the computational effort, in this paper a new strategy is proposed whereby the analysis for tracking the discontinuity path is restricted to the domain formed by some elements near the crack surface that develops along the loading process. The proposed methodology is validated by performing three-dimensional analyses of basic problems of experimental fractures and comparing their results with those reported in the literature.

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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)

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Amino acids play essential roles in both metabolism and the proteome. Many studies have profiled free amino acids (FAAs) or proteins; however, few have connected the measurement of FAA with individual amino acids in the proteome. In this study, we developed a metabolomics method to comprehensively analyze amino acids in different domains, using two examples of different sample types and disease models. We first examined the responses of FAAs and insoluble-proteome amino acids (IPAAs) to the Myc oncogene in Tet21N human neuroblastoma cells. The metabolic and proteomic amino acid profiles were quite different, even under the same Myc condition, and their combination provided a better understanding of the biological status. In addition, amino acids were measured in 3 domains (FAAs, free and soluble-proteome amino acids (FSPAAs), and IPAAs) to study changes in serum amino acid profiles related to colon cancer. A penalized logistic regression model based on the amino acids from the three domains had better sensitivity and specificity than that from each individual domain. To the best of our knowledge, this is the first study to perform a combined analysis of amino acids in different domains, and indicates the useful biological information available from a metabolomics analysis of the protein pellet. This study lays the foundation for further quantitative tracking of the distribution of amino acids in different domains, with opportunities for better diagnosis and mechanistic studies of various diseases.

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Collectively, the observations indicate that the overall warming of the Arctic system continued in 2007. There are some elements that are stabilizing or returning to climatological norms. These mixed tendencies illustrate the sensitivity and complexity of the Arctic System. Atmosphere: Hot spot shifts toward Europe Ocean: North Pole Temperatures at depth returning to 1990s values Sea Ice: Summer extent at record minimum Greenland: Recent warm temperatures associated with net ice loss Biology: increasing tundra shrub cover and variable treeline advance; up to 80% declines in some caribou herds while goose populations double Land: Increase in permafrost temperatures The Arctic Report Card 2007 is introduced as a means of presenting clear, reliable and concise information on recent observations of environmental conditions in the Arctic, relative to historical time series records. It provides a method of updating and expanding the content of the State of the Arctic Report, published in fall 2006, to reflect current conditions. Material presented in the Report Card is prepared by an international team of scientists and is peer-reviewed by topical experts nominated by the US Polar Research Board. The audience for the Arctic Report Card is wide, including scientists, students, teachers, decision makers and the general public interested in Arctic environment and science. The web-based format will facilitate future timely updates of the content.

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A derivative spectrophotometric method was validated for quzintification of acyclovir in poly (n-butylcyanoacrylate) (PBCA) nanoparticles. Specificity, linearity. precision, accuracy, recovery. detection (LOD) and quantification (LOQ) Inuits were established for method validation. First-derivative it 295.2 nm eliminated interferences from nanoparticle ingredients and presented linearity for acyclovir concentrations ranging front 1.25 to 40.0 mu g/mL. (r = 0.9999). Precision and accuracy data demonstrated good reproducibility. Recovery ranged from 99.3 to 101.2. LOD) was 0.08 mu g/mL and LOQ. 0.25 mu g/mL. Thus. the proposed method proved to be easy. low cost. and accurate, and therefore, an useful alternative to quantify acyclovir in nanoparticles.

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Background: The high and increasing prevalence of Dilated Cardiomyopathy (DCM) represents a serious public health issue. Novel technologies have been used aiming to improve diagnosis and the therapeutic approach. In this context, speckle tracking echocardiography (STE) uses natural myocardial markers to analyze the systolic deformation of the left ventricle (LV). Objective: Measure the longitudinal transmural global strain (GS) of the LV through STE in patients with severe DCM, comparing the results with normal individuals and with echocardiographic parameters established for the analysis of LV systolic function, in order to validate the method in this population. Methods: Seventy-one patients with severe DCM (53 +/- 12 years, 72% men) and 20 controls (30 +/- 8 years, 45% men) were studied. The following variables were studied: LV volumes and ejection fraction calculated by two and three-dimensional echocardiography, Doppler parameters, Tissue Doppler Imaging systolic and diastolic LV velocities and GS obtained by STE. Results: Compared with controls, LV volumes were higher in the DCM group; however, LVEF and peak E-wave velocity were lower in the latter. The myocardial performance index was higher in the patient group. Tissue Doppler myocardial velocities (S', e', a') were significantly lower and E/e' ratio was higher in the DCM group. GS was decreased in the DCM group (-5.5% +/- 2.3%) when compared with controls (-14.0% +/- 1.8%). Conclusion: In this study, GS was significantly lower in patients with severe DCM, bringing new perspectives for therapeutic approaches in this specific population. (Arq Bras Cardiol 2012;99(3):834-842)

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Pollen traps used for harvesting pollen from Apis mellifera do not work for stingless bees, as most species have small entrances and rapidly deposit large quantities of propolis at any barrier in front of the nest. Some stingless beekeepers harvest pollen by removing it directly from pollen pots, but this pollen is normally fermented and unpalatable. The aim of this study was to test a new method for harvesting pollen from stingless bee colonies before it begins to ferment. Colonies of Scaptotrigona depilis were removed and replaced by empty hives, which were occupied by the returning foragers and used for storing pollen and nectar. After one week, the pollen and honey were harvested directly from the storing pots and weighed. On average, the colonies produced 8.7 g of honey and 54.2 g of unfermented pollen (n = 10). This method is a viable option for harvesting unfermented pollen from stingless bees, especially with species that harvest large amounts of pollen. The unfermented pollen of S. depilis was well received in taste tests, receiving higher scores than fermented pollen, and similar scores to A. mellifera pollen, so could have great commercial possibilities. It is also a good method for studying the foraging of stingless bees because the amount of harvested food can be easily and precisely quantified.