967 resultados para Séries temporelles


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OBJETIVO: Verificar a efetividade da técnica de pressão expiratória positiva oscilante (PEPO) utilizando pressões expiratórias pré-determinadas sobre a viscosidade e a transportabilidade do escarro em pacientes com bronquiectasia. MÉTODOS: Foram incluídos no estudo 15 pacientes estáveis com bronquiectasia (7 homens; média de idade = 53 ± 16 anos), submetidos a duas intervenções PEPO consecutivas, com 24 h de intervalo entre si, utilizando pressões expiratórias de 15 cmH2O (P15) e 25 cmH2O (P25). O protocolo consistiu de tosse voluntária; nova expectoração voluntária após 20 min, denominado tempo zero (T0); repouso de 10 min; e utilização da técnica em duas séries de 10 min (S1 e S2) de PEPO em P15 e P25, com intervalo de 10 min entre si. A viscosidade e transportabilidade do escarro foram avaliadas pela viscosimetria, velocidade relativa de transporte no palato de rã, deslocamento em máquina simuladora de tosse e ângulo de adesão. As amostras de escarro foram coletadas em T0, após S1 e após S2. Testes estatísticos específicos foram aplicados de acordo com a distribuição dos dados. RESULTADOS: Houve diminuição significante da viscosidade do escarro após S1 em P15 e após S2 em P25. Não houve diferenças significantes entre todas as amostras para a transportabilidade. CONCLUSÕES: Houve diminuição da viscosidade do escarro quando a PEPO foi realizada em P15 e P25, o que sugere que não seja necessário gerar alta pressão expiratória para obter o resultado desejado.

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O objetivo deste estudo foi avaliar o efeito da técnica de oscilação oral de alta freqüência (com o aparelho Shaker), aplicada em diferentes pressões expiratórias (PE), sobre a função autonômica e parâmetros cardiorrespiratórios. Foram coletados dados de 20 voluntários jovens saudáveis (21,6±1,3 anos), que permaneceram em repouso inicial por 10 minutos e, em seguida, fizeram três séries de dez expirações no aparelho (com intervalo de descanso de 2 minutos entre as séries) em três diferentes PE - pressão livre (PL), de 10 (P10) e de 20 (P20) cmH2O - permanecendo por mais 10 minutos em repouso final. Os dados foram analisados estatisticamente, com nível de significância de 5%. Após a aplicação da técnica, constatou-se diferença significante nos índices de variabilidade da freqüência cardíaca em PL e um aumento significante na pressão arterial sistólica em P20. Na pressão arterial diastólica, freqüência respiratória e saturação periférica de oxigênio não foram encontradas diferenças antes, durante e após a técnica, nas diferentes PE. A percepção do esforço aumentou significantemente ao longo das séries em PL e P20 e entre P10 e P20 em cada série. A freqüência cardíaca (FC) aumentou e diminuiu em sincronia com os movimentos de inspiração e expiração, respectivamente. Foram observadas modificações na modulação autonômica do coração em PL. A aplicação da técnica nessa população, nas diferentes PE analisadas, promoveu modificações no comportamento da FC, no esforço percebido e, em PL, na modulação autonômica do coração.

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São apresentadas séries históricas de indicadores demográficos e sanitários para a população com 60 anos e mais do Brasil, Estado de São Paulo e Município de Araraquara, de porte médio. em 1991, os idosos eram 7,8% da população brasileira e 9,7% de Araraquara, superando em número as crianças menores de 5 anos (8,9%). Aumentou o peso relativo do segmento com mais idade (70 anos e mais), que já representa 40% do total, assim como o índice de urbanização dos idosos, 93,7% no Estado e 96,3% no Município, acima da média da população em geral em 1991. As principais causas de morte são as doenças do aparelho circulatório (40% do total de óbitos) e os neoplasmas (15%). São sugeridas medidas para a assistência à saúde dos idosos: a) expansão da capacidade atual de atendimento, através do treinamento gerontológico de médicos generalistas e enfermeiros da rede pública e privada; b) incremento das atividades educativas já existentes, dirigidas aos idosos, profissionais da saúde e educadores do ensino médio; c) incremento do programa de visita domiciliar aos idosos e criação de hospital-dia para evitar internações necessárias e garantir a manutenção dos baixos níveis atuais de institucionalização em asilos (0,7% em Araraquara). A existência de pelo menos 35% dos idosos de Araraquara, com acesso à assistência privada à saúde, reforça a importância da inclusão desses serviços nos programas locais de saúde da terceira idade.

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In this work we have studied, by Monte Carlo computer simulation, several properties that characterize the damage spreading in the Ising model, defined in Bravais lattices (the square and the triangular lattices) and in the Sierpinski Gasket. First, we investigated the antiferromagnetic model in the triangular lattice with uniform magnetic field, by Glauber dynamics; The chaotic-frozen critical frontier that we obtained coincides , within error bars, with the paramegnetic-ferromagnetic frontier of the static transition. Using heat-bath dynamics, we have studied the ferromagnetic model in the Sierpinski Gasket: We have shown that there are two times that characterize the relaxation of the damage: One of them satisfy the generalized scaling theory proposed by Henley (critical exponent z~A/T for low temperatures). On the other hand, the other time does not obey any of the known scaling theories. Finally, we have used methods of time series analysis to study in Glauber dynamics, the damage in the ferromagnetic Ising model on a square lattice. We have obtained a Hurst exponent with value 0.5 in high temperatures and that grows to 1, close to the temperature TD, that separates the chaotic and the frozen phases

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The study of sunspots consistently contributed to a better understanding of magnetic phenomena of the Sun, as its activity. It was found with the dynamics of sunspots that the Sun has a rotation period of twenty-seven days around your axis. With the help of Project Sun-As-A-Star that solar spectra obtained for more than thirty years we observed oscillations of both the depth of the spectral line and its equivalent width, and analysis of the return information about the characteristics of solar magnetism. It also aims to find patterns of solar magnetic activity cycle and the average period of rotation of the Sun will indicate the spectral lines that are sensitive to magnetic activity and which are not. Sensitive lines how Ti II 5381.0 Å stands as the best indicator of the solar rotation period and also shows different periods of rotation cycles of minimum and maximum magnetic activity. It is the first time we observe clearly distinct rotation periods in the different cycles. The analysis also shows that Ca II 8542.1 Å and HI 6562.0 Å indicate the cycle of magnetic activity of eleven years. Some spectral lines no indicated connection with solar activity, this result can help us search for programs planets using spectroscopic models. Data analysis was performed using the Lomb-Scargle method that makes the time series analysis for unequally spaced data. Observe different rotation periods in the cycles of magnetic activity accounts for a discussion has been debated for many decades. We verified that spectroscopy can also specify the period of stellar rotation, thus being able to generalize the method to other stars

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Stellar differential rotation is an important key to understand hydromagnetic stellar dynamos, instabilities, and transport processes in stellar interiors as well as for a better treatment of tides in close binary and star-planet systems. The space-borne high-precision photometry with MOST, CoRoT, and Kepler has provided large and homogeneous datasets. This allows, for the first time, the study of differential rotation statistically robust samples covering almost all stages of stellar evolution. In this sense, we introduce a method to measure a lower limit to the amplitude of surface differential rotation from high-precision evenly sampled photometric time series such as those obtained by space-borne telescopes. It is designed for application to main-sequence late-type stars whose optical flux modulation is dominated by starspots. An autocorrelation of the time series is used to select stars that allow an accurate determination of spot rotation periods. A simple two-spot model is applied together with a Bayesian Information Criterion to preliminarily select intervals of the time series showing evidence of differential rotation with starspots of almost constant area. Finally, the significance of the differential rotation detection and a measurement of its amplitude and uncertainty are obtained by an a posteriori Bayesian analysis based on a Monte Carlo Markov Chain (hereafter MCMC) approach. We apply our method to the Sun and eight other stars for which previous spot modelling has been performed to compare our results with previous ones. The selected stars are of spectral type F, G and K. Among the main results of this work, We find that autocorrelation is a simple method for selecting stars with a coherent rotational signal that is a prerequisite to a successful measurement of differential rotation through spot modelling. For a proper MCMC analysis, it is necessary to take into account the strong correlations among different parameters that exists in spot modelling. For the planethosting star Kepler-30, we derive a lower limit to the relative amplitude of the differential rotation. We confirm that the Sun as a star in the optical passband is not suitable for a measurement of the differential rotation owing to the rapid evolution of its photospheric active regions. In general, our method performs well in comparison with more sophisticated procedures used until now in the study of stellar differential rotation

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The interest in the systematic analysis of astronomical time series data, as well as development in astronomical instrumentation and automation over the past two decades has given rise to several questions of how to analyze and synthesize the growing amount of data. These data have led to many discoveries in the areas of modern astronomy asteroseismology, exoplanets and stellar evolution. However, treatment methods and data analysis have failed to follow the development of the instruments themselves, although much effort has been done. In present thesis, we propose new methods of data analysis and two catalogs of the variable stars that allowed the study of rotational modulation and stellar variability. Were analyzed the photometric databases fromtwo distinctmissions: CoRoT (Convection Rotation and planetary Transits) and WFCAM (Wide Field Camera). Furthermore the present work describes several methods for the analysis of photometric data besides propose and refine selection techniques of data using indices of variability. Preliminary results show that variability indices have an efficiency greater than the indices most often used in the literature. An efficient selection of variable stars is essential to improve the efficiency of all subsequent steps. Fromthese analyses were obtained two catalogs; first, fromtheWFCAMdatabase we achieve a catalog with 319 variable stars observed in the photometric bands Y ZJHK. These stars show periods ranging between ∼ 0, 2 to ∼ 560 days whose the variability signatures present RR-Lyrae, Cepheids , LPVs, cataclysmic variables, among many others. Second, from the CoRoT database we selected 4, 206 stars with typical signatures of rotationalmodulation, using a supervised process. These stars show periods ranging between ∼ 0, 33 to ∼ 92 days, amplitude variability between ∼ 0, 001 to ∼ 0, 5 mag, color index (J - H) between ∼ 0, 0 to ∼ 1, 4 mag and spectral type CoRoT FGKM. The WFCAM variable stars catalog is being used to compose a database of light curves to be used as template in an automatic classifier for variable stars observed by the project VVV (Visible and Infrared Survey Telescope for Astronomy) moreover it are a fundamental start point to study different scientific cases. For example, a set of 12 young stars who are in a star formation region and the study of RR Lyrae-whose properties are not well established in the infrared. Based on CoRoT results we were able to show, for the first time, the rotational modulation evolution for an wide homogeneous sample of field stars. The results are inagreement with those expected by the stellar evolution theory. Furthermore, we identified 4 solar-type stars ( with color indices, spectral type, luminosity class and rotation period close to the Sun) besides 400 M-giant stars that we have a special interest to forthcoming studies. From the solar-type stars we can describe the future and past of the Sun while properties of M-stars are not well known. Our results allow concluded that there is a high dependence of the color-period diagram with the reddening in which increase the uncertainties of the age-period realized by previous works using CoRoT data. This thesis provides a large data-set for different scientific works, such as; magnetic activity, cataclysmic variables, brown dwarfs, RR-Lyrae, solar analogous, giant stars, among others. For instance, these data will allow us to study the relationship of magnetic activitywith stellar evolution. Besides these aspects, this thesis presents an improved classification for a significant number of stars in the CoRoT database and introduces a new set of tools that can be used to improve the entire process of the photometric databases analysis