48 resultados para Equaçõesdiferenciais parciais


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Este estudio tiene por objeto investigar la política de democratización de la administración educativa de la consideración de los procesos socio-históricos que participaron en el programa de modernización de los paradigmas de administración, por la forma en que la política de descuentos y que se entiende por los sujetos dentro de la escuela. Se considera que la democracia defendida por la política de democratización de la educación por el neoliberalismo / gerencialismo, siendo el resultado de un acuerdo que aspira a dirigir la sociedad hegemónica, portador del gen, las diferentes concepciones de la democracia, por lo tanto, en su en el interior se colocan en posición, los elementos conceptuales de los diferentes proyectos de la sociedad. Por lo tanto, vamos a ver cómo, en el Estado Dom Escuela Nivaldo Monte, esta política se (re) significado y transformado por los sujetos, incluyendo las diferentes formas que se delinean en la dimensión de la democracia, autonomía, participación y representación. Aborda el tema de estudio en vista del materialismo histórico y dialéctico, por lo que consideramos que es posible examinar el objeto en sus fronteras, pero no de manera fragmentada o enajenados o la mediación de la determinación del capital económico, político, cultural y simbólica de la sociabilidad la globalización, para superar los matices asignado a estructuralista metodología de diseño teórico adoptado, usado, en el entendimiento de que considera que la macro y micro estructuras están formadas por una relación de complementariedad entre los procesos micro y macro. Entre nuestras conclusiones parciales, que argumentan que la gestión democrática y la gestión de la administración son diferentes formas de administración, antagónicos, aunque este efecto fue una especie de coincidencia, le distinguen: en primer lugar, si queremos apoyar la calidad de las escuelas públicas, y en segundo lugar que la organización de gestión crea las condiciones para la gestión democrática legal y legítimo, mientras que se establecen las condiciones que tanto impracticable y difícil como imposible y muy difícil de llevar a cabo la gestión de la administración que conduce a la conclusión de que, finalmente, la gestión democrática es imposible de llevarse a cabo por medio de la gerencia pública y la gerencia pública es imposible de llevarse a cabo por medio de la democracia. Sin embargo, la participación institucionalizada de la gerencia pública puede promover la extensión del control social sobre el estado y contribuir a la transformación social, que parece que está un reto difícil, pero no improbable, y es probable que se siga investigando.

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Currently, there are several power converter topologies applied to wind power generation. The converters allow the use of wind turbines operating at variable speed, enabling better use of wind forces. The high performance of the converters is being increasingly demanded, mainly because of the increase in the power generation capacity by wind turbines, which gave rise to various converter topologies, such as parallel or multilevel converters. The use of converters allow effective control of the power injected into the grid, either partially, for the case using partial converter, or total control for the case of using full converter. The back-to-back converter is one of the most used topologies in the market today, due to its simple structure, with few components, contributing to robust and reliable performance. In this work, is presented the implementation of a wind cogeneration system using a permanent magnet synchronous generator (PMSG) associated with a back-to-back power converter is proposed, in order to inject active power in an electric power system. The control strategy of the active power delivered to the grid by cogeneration is based on the philosophy of indirect control

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The present work has the main goal to study the modeling and simulation of a biphasic separator with induced phase inversion, the MDIF, with the utilization of the finite differences method for the resolution of the partial differencial equations which describe the transport of contaminant s mass fraction inside the equipment s settling chamber. With this aim, was developed the deterministic differential model AMADDA, wich was admensionalizated and then semidiscretizated with the method of lines. The integration of the resultant system of ordinary differential equations was realized by means of a modified algorithm of the Adam-Bashfort- Moulton method, and the sthocastic optimization routine of Basin-Hopping was used in the model s parameter estimation procedure . With the aim to establish a comparative referential for the results obtained with the model AMADDA, were used experimental data presented in previous works of the MDIF s research group. The experimental data and those obtained with the model was assessed regarding its normality by means of the Shapiro-Wilk s test, and validated against the experimental results with the Student s t test and the Kruskal-Wallis s test, depending on the result. The results showed satisfactory performance of the model AMADDA in the evaluation of the MDIF s separation efficiency, being possible to determinate that at 1% significance level the calculated results are equivalent to those determinated experimentally in the reference works

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The semiarid rainfall regime is northeastern Brazil is highly variable. Climate processes associated with rainfall are complex and their effects may represent extreme situations of drought or floods, which can have adverse effects on society and the environment. The regional economy has a significant agricultural component, which is strongly influenced by weather conditions. Maximum precipitation analysis is traditionally performed using the intensity-duration-frequency (IDF) probabilistic approach. Results from such analysis are typically used in engineering projects involving hydraulic structures such as drainage network systems and road structures. On the other hand, precipitation data analysis may require the adoption of some kind of event identification criteria. The minimum inter-event duration (IMEE) is one of the most used criteria. This study aims to analyze the effect of the IMEE on the obtained rain event properties. For this purpose, a nine-year precipitation time series (2002- 2011) was used. This data was obtained from an automatic raingauge station, installed in an environmentally protected area, Ecological Seridó Station. The results showed that adopted IMEE values has an important effect on the number of events, duration, event height, mean rainfall rate and mean inter-event duration. Furthermore, a higher occurrence of extreme events was observed for small IMEE values. Most events showed average rainfall intensity higher than 2 mm.h-1 regardless of IMEE. The storm coefficient of advance was, in most cases, within the first quartile of the event, regardless of the IMEE value. Time series analysis using partial time series made it possible to adjust the IDF equations to local characteristics

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The fauna of Brazilian reef fishes comprises approximately 320 species distributed along the coast of the mainland and islands ocean. Little is known about the levels of connectivity between their populations, but has been given the interest in the relations between the offshore and the islands of the Brazil, in a biogeographical perspective. The oceanic islands Brazilian hosting a considerable number of endemic species, which are locally abundant, and divide a substantial portion of its reef fish fauna with the Western Atlantic. Among the richest families of reef fish in species are Pomacentridae. This study analyzed through analysis of sequences of the mitochondrial DNA control region (D-loop), the standards-breeding population of C. Multilineata in different areas of the NE coast of Brazil, involving both oceanic islands (Fernando de Noronha Archipelago and of St. Peter and St. Paul) and continental shelf (RN and BA). To this aim, partial sequences were used in the region HVR1 of mtDNA (312pb). The population structure and parameters for the estimates of genetic variability, molecular variance (AMOVA), estimation of the index for fixing (FST) and number of migrants were determined. The phylogenetic relationships between the populations were estimated using neighbor-joining (NJ) method. A group of Bayesian analysis was used to verify population structure, according to haplotype frequency of each individual. The genetic variability of populations was extremely high. The populations sampled show moderate genetic structure, with a higher degree of genetic divergence being observed for the sample of the Archipelago of St. Peter and St. Paul. At smaller geographical scale, the sample of Rio Grande do Norte and the Archipelago of Fernando de Noronha do not have genetic differentiation. Three moderately differentiated population groups were identified: a population group (I), formed by the Rio Grande do Norte (I') and the archipelago of Fernando de Noronha (I''), and two other different groups formed by the island population of the archipelago of Saint Peter and St. Paul (II) and Bahia (III). The genetic patterns found suggest that the species has suffered a relatively recent radiation favoring the absence of shared haplotypes. C. multilineata seems to constitute a relatively homogenous population along the West Atlantic coast, with evidence of a moderate population genetic structure in relation to the Archipelago of St. Peter and St. Paul. These data supports the importance of the dispersal larvae by marine current and the interpopulation similarity this species.

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Nas últimas décadas, com a significativa redução da cárie dentária em crianças e adolescentes, uma maior atenção tem sido dada a outros problemas bucais como as oclusopatias. Em termos epidemiológicos no Brasil, esta tem ocupado o terceiro lugar dentre os problemas de saúde oral na população e, portanto, a inclusão destas como um problema de saúde pública se deve não apenas à sua alta prevalência, mas também ao impacto social, que interfere diretamente na qualidade de vida das pessoas. Diante do exposto é que este estudo objetiva buscar o impacto da presença e severidade das oclusopatias e suas respectivas necessidades de tratamento na qualidade de vida de adolescentes escolares de um município. Sendo assim, foram examinados 356 escolares na faixa etária de 15 -19 anos e determinadas a prevalência, severidade e necessidade de tratamento de oclusopatias através dos índices DAI, IOTN e ICON. O impacto sócio dentário das oclusopatias na qualidade de vida dos adolescentes foi analisado através do índice CS-OIDP. A fim de se verificar possíveis influências de variáveis estudadas na determinaçao do impacto na qualidade de vida das oclusopatias, estas serão coletadas através do estatus sócio-econômico, gênero, idade e tipo escola. Nos resultados parciais, relacionado a 50% da amostra, se observou uma maior prevalência do escolares de escola pública(68,1%), idade entre 15-16 anos(74,7%), gênero feminino(52,7%) e maior prevalência do SES baixo(77,5%). A análise estatística usando o teste qui-quadrado mostrou uma associação significativa do impacto da oclusopatia na qualidade de vida apenas quando avaliada com o índice ICON e o A-IOTN do examinado, comprovando uma associação da necessidade de tratamento com a presença do impacto na qualidade de vida. Com isso, busca-se comprovar e enfatizar a necessidade de se estabelecer políticas públicas que trabalhem na prevenção e interceptação dessas oclusopatias na população, melhorando, portanto, a qualidade de vida e saúde oral dos adolescentes.

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Nas últimas décadas, com a significativa redução da cárie dentária em crianças e adolescentes, uma maior atenção tem sido dada a outros problemas bucais como as oclusopatias. Em termos epidemiológicos no Brasil, esta tem ocupado o terceiro lugar dentre os problemas de saúde oral na população e, portanto, a inclusão destas como um problema de saúde pública se deve não apenas à sua alta prevalência, mas também ao impacto social, que interfere diretamente na qualidade de vida das pessoas. Diante do exposto é que este estudo objetiva buscar o impacto da presença e severidade das oclusopatias e suas respectivas necessidades de tratamento na qualidade de vida de adolescentes escolares de um município. Sendo assim, foram examinados 356 escolares na faixa etária de 15 -19 anos e determinadas a prevalência, severidade e necessidade de tratamento de oclusopatias através dos índices DAI, IOTN e ICON. O impacto sócio dentário das oclusopatias na qualidade de vida dos adolescentes foi analisado através do índice CS-OIDP. A fim de se verificar possíveis influências de variáveis estudadas na determinaçao do impacto na qualidade de vida das oclusopatias, estas serão coletadas através do estatus sócio-econômico, gênero, idade e tipo escola. Nos resultados parciais, relacionado a 50% da amostra, se observou uma maior prevalência do escolares de escola pública(68,1%), idade entre 15-16 anos(74,7%), gênero feminino(52,7%) e maior prevalência do SES baixo(77,5%). A análise estatística usando o teste qui-quadrado mostrou uma associação significativa do impacto da oclusopatia na qualidade de vida apenas quando avaliada com o índice ICON e o A-IOTN do examinado, comprovando uma associação da necessidade de tratamento com a presença do impacto na qualidade de vida. Com isso, busca-se comprovar e enfatizar a necessidade de se estabelecer políticas públicas que trabalhem na prevenção e interceptação dessas oclusopatias na população, melhorando, portanto, a qualidade de vida e saúde oral dos adolescentes.

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The aim of this study is to quantify the presence of major and minor elements in the sediments of estuary Potengi. Four georeferenced sampling points were used in the study, at which sediment samples were collected in the channel of the river and on the right and left banks. In addition, dissolved oxygen, salinity and water conductivity were taken in situ at the time of sample collection. The percentage of organic matter, determined by gravimetry, and granulometric analysis of the sediment samples were conducted in the laboratory. To quantify the major and minor elements a prior test to open the sample was conducted with standard NIST 1646ª estuarine sediment to choose the best methodology to be adopted. The sediment samples were dissolved in microwaves with nitric acid and chloridric acid, according to methodology proposed by US EPA 3051ª. Quantitative analyses of the elements Al, Fe, Cd, Cr, Cu, Mn, Ni, Pb and Zn were conducted by inductively coupled plasma optical emission spectrometry (ICPOES). The results showed that the partial concentrations of the elements analyzed are below average worldwide shale levels, the standard described by Turekian and Wedepohl (1961)

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In this work we used chemometric tools to classify and quantify the protein content in samples of milk powder. We applied the NIR diffuse reflectance spectroscopy combined with multivariate techniques. First, we carried out an exploratory method of samples by principal component analysis (PCA), then the classification of independent modeling of class analogy (SIMCA). Thus it became possible to classify the samples that were grouped by similarities in their composition. Finally, the techniques of partial least squares regression (PLS) and principal components regression (PCR) allowed the quantification of protein content in samples of milk powder, compared with the Kjeldahl reference method. A total of 53 samples of milk powder sold in the metropolitan areas of Natal, Salvador and Rio de Janeiro were acquired for analysis, in which after pre-treatment data, there were four models, which were employed for classification and quantification of samples. The methods employed after being assessed and validated showed good performance, good accuracy and reliability of the results, showing that the NIR technique can be a non invasive technique, since it produces no waste and saves time in analyzing the samples

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In this work calibration models were constructed to determine the content of total lipids and moisture in powdered milk samples. For this, used the near-infrared spectroscopy by diffuse reflectance, combined with multivariate calibration. Initially, the spectral data were submitted to correction of multiplicative light scattering (MSC) and Savitzsky-Golay smoothing. Then, the samples were divided into subgroups by application of hierarchical clustering analysis of the classes (HCA) and Ward Linkage criterion. Thus, it became possible to build regression models by partial least squares (PLS) that allowed the calibration and prediction of the content total lipid and moisture, based on the values obtained by the reference methods of Soxhlet and 105 ° C, respectively . Therefore, conclude that the NIR had a good performance for the quantification of samples of powdered milk, mainly by minimizing the analysis time, not destruction of the samples and not waste. Prediction models for determination of total lipids correlated (R) of 0.9955, RMSEP of 0.8952, therefore the average error between the Soxhlet and NIR was ± 0.70%, while the model prediction to content moisture correlated (R) of 0.9184, RMSEP, 0.3778 and error of ± 0.76%

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This work is combined with the potential of the technique of near infrared spectroscopy - NIR and chemometrics order to determine the content of diclofenac tablets, without destruction of the sample, to which was used as the reference method, ultraviolet spectroscopy, which is one of the official methods. In the construction of multivariate calibration models has been studied several types of pre-processing of NIR spectral data, such as scatter correction, first derivative. The regression method used in the construction of calibration models is the PLS (partial least squares) using NIR spectroscopic data of a set of 90 tablets were divided into two sets (calibration and prediction). 54 were used in the calibration samples and the prediction was used 36, since the calibration method used was crossvalidation method (full cross-validation) that eliminates the need for a validation set. The evaluation of the models was done by observing the values of correlation coefficient R 2 and RMSEC mean square error (calibration error) and RMSEP (forecast error). As the forecast values estimated for the remaining 36 samples, which the results were consistent with the values obtained by UV spectroscopy

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In this work, the quantitative analysis of glucose, triglycerides and cholesterol (total and HDL) in both rat and human blood plasma was performed without any kind of pretreatment of samples, by using near infrared spectroscopy (NIR) combined with multivariate methods. For this purpose, different techniques and algorithms used to pre-process data, to select variables and to build multivariate regression models were compared between each other, such as partial least squares regression (PLS), non linear regression by artificial neural networks, interval partial least squares regression (iPLS), genetic algorithm (GA), successive projections algorithm (SPA), amongst others. Related to the determinations of rat blood plasma samples, the variables selection algorithms showed satisfactory results both for the correlation coefficients (R²) and for the values of root mean square error of prediction (RMSEP) for the three analytes, especially for triglycerides and cholesterol-HDL. The RMSEP values for glucose, triglycerides and cholesterol-HDL obtained through the best PLS model were 6.08, 16.07 e 2.03 mg dL-1, respectively. In the other case, for the determinations in human blood plasma, the predictions obtained by the PLS models provided unsatisfactory results with non linear tendency and presence of bias. Then, the ANN regression was applied as an alternative to PLS, considering its ability of modeling data from non linear systems. The root mean square error of monitoring (RMSEM) for glucose, triglycerides and total cholesterol, for the best ANN models, were 13.20, 10.31 e 12.35 mg dL-1, respectively. Statistical tests (F and t) suggest that NIR spectroscopy combined with multivariate regression methods (PLS and ANN) are capable to quantify the analytes (glucose, triglycerides and cholesterol) even when they are present in highly complex biological fluids, such as blood plasma

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The aim of this study was to evaluate the potential of near-infrared reflectance spectroscopy (NIRS) as a rapid and non-destructive method to determine the soluble solid content (SSC), pH and titratable acidity of intact plums. Samples of plum with a total solids content ranging from 5.7 to 15%, pH from 2.72 to 3.84 and titratable acidity from 0.88 a 3.6% were collected from supermarkets in Natal-Brazil, and NIR spectra were acquired in the 714 2500 nm range. A comparison of several multivariate calibration techniques with respect to several pre-processing data and variable selection algorithms, such as interval Partial Least Squares (iPLS), genetic algorithm (GA), successive projections algorithm (SPA) and ordered predictors selection (OPS), was performed. Validation models for SSC, pH and titratable acidity had a coefficient of correlation (R) of 0.95 0.90 and 0.80, as well as a root mean square error of prediction (RMSEP) of 0.45ºBrix, 0.07 and 0.40%, respectively. From these results, it can be concluded that NIR spectroscopy can be used as a non-destructive alternative for measuring the SSC, pH and titratable acidity in plums

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Aiming to consumer s safety the presence of pathogenic contaminants in foods must be monitored because they are responsible for foodborne outbreaks that depending on the level of contamination can ultimately cause the death of those who consume them. In industry is necessary that this identification be fast and profitable. This study shows the utility and application of near-infrared (NIR) transflectance spectroscopy as an alternative method for the identification and classification of Escherichia coli and Salmonella Enteritidis in commercial fruit pulp (pineapple). Principal Component Analysis (PCA), Independent Modeling of Class Analogy (SIMCA) and Discriminant Analysis Partial Least Squares (PLS-DA) were used in the analysis. It was not possible to obtain total separation between samples using PCA and SIMCA. The PLS-DA showed good performance in prediction capacity reaching 87.5% for E. coli and 88.3% for S. Enteritides, respectively. The best models were obtained for the PLS-DA with second derivative spectra treated with a sensitivity and specificity of 0.87 and 0.83, respectively. These results suggest that the NIR spectroscopy and PLS-DA can be used to discriminate and detect bacteria in the fruit pulp

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Aim: To determine the frequency and type of complications related to removable partial denture (RPD) less, Kennedy Class I, over time . Materials and Methods: This observational study consisted of a sample of 65 users PPR lower arches in Kennedy Class I and dentures, rehabilitated in the Department of Dentistry, Federal University of Rio Grande do Norte (UFRN). Patients were followed through periodic controls during periods of 60 days, 6 months and 1 year from installation. After the first year of control had other returns annually. The occurrence of complications or prosthetic failure was observed and recorded in a specific clinical record over 39 months. The patterns of failures observed were classified in the following situations: occurrence of traumatic ulcers after 2 months of installation, lack of retention, fracture or caries in the rest, fracture or dislocation of the artificial teeth, the larger connector fracture, fracture clip fracture support, poor support (need to reline the denture) and prosthesis fracture. Results: The incidence of complications was low frequency, being higher in the second year of use of the prosthesis. Among the complications that occurred more is the loss of retention (31.57%). Failures more severe and difficult to solve as the fracture elements of the metal structure of the PPR had low occurrence and were represented by only one case of the larger connector (5.3%) fractures. Conclusion: Removable partial dentures mandibular free end opposing of the conventional dentures have a low complication rate after 39 months of use when subjected to periodic controls