928 resultados para improved principal components analysis (IPCA) algorithm


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

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Stroke is a neurological disorder caused by restriction of blood flow to the brain, which generates directly a deficit of functionality that affects the quality of life of patients. The aim of this study was to establish a short version of the Social Rhythm Scale (SRM), to assess the social rhythm of stroke patients. The sample consisted of 84 patients, of both sexes, with injury time exceeding 6 months. For seven days, patients recorded the time held 17 activities of SRM. Data analysis was performed using a principal components factor analysis with varimax rotation of the full version of SRM in order to determine which activities could compose brief versions of SRM. We then carried out a comparison of hits, the ALI (Level Activity Index) and SRM, between versions, by Kruskal-Walls and the Mann-Whitney test. The Spearman correlation test was used to evaluate the correlation between the score of the full version of SRM with short versions. It was found that the activities of SRM were distributed in three versions: the first and second with 6 activities and third with 3 activities. Regarding hits, it was found that they ranged from 4.9 to 5.8 on the first version; 2.3 to 3.8 in version 2 and 2.8 to 6.2 in version 3, the first the only version that did not show low values. The analysis of ALI, in version 1, the median was 29, in version 2 was 14 and in version 3 was 18. Significant difference in the values of ALI between versions 1 and 2, between 2 and 3 and between versions 1 and 3. The highest median was found in the first version, formed by activities: out of bed, first contact, drink coffee, watch TV in the evening and go to bed. The lowest median was observed in the second version and this was not what had fewer activities, but which had social activities. The medians of the SRM version 1 was 6, version 2 was 4 and version 3 was 6. Significant difference in the values of SRM between versions 1 and 2 and between 2 and 3, but no significant difference between versions 1 and 3. Through analysis, we found a significant correlation only between the full version and the version 1 (R2 = 0.61) (p <0.05), no correlation was found with version 2 (R2 = 0.007) nor with version 3 (R2 = 0.002), this was finally a factor to consider version 1 as the short brazilian version of the Social Rhythm Metric for stroke patients

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Population aging is one of the greatest challenges to contemporary public health and, in this perspective, the functional capacity emerges as an important feature in geriatric assessment. The oral health of elderly, in turn, deserves special attention because, historically, in the dental services, this population group was not considered a priority for attention, which is verified by high rates of edentulism found even among these individuals. The present study proposes to examine the relationship between oral health status and functional capacity in an elderly population. To this end, intra-oral epidemiological examination was performed to assess the degree of dental caries, periodontal status, use and need of prosthesis and the presence of lesions. Functional capacity was assessed by the Independence in Activities of Daily Living, which considers the independence or not in the performance of six self-care functions. Socioeconomic and demographic characteristics and general health status were also investigated, in view of the possibility of intervention of these variables in the investigated relation. An factor analysis of the principal components was conducted which resulted four indicators of oral health conditions, representative of the population studied. 441 seniors were enrolled with mean age of 71.7 (± 8.7) years, the majority being female (68%). Functional capacity was dichotomized into completely independent individuals (89.6%) and dependent on at least one of the functions considered (10.4%). There was an association between functional capacity and the indicators related to the presence of many teeth and dental caries, and to that associated with the use and need of prostheses. These associations in turn, lost statistical significance when adjusting for confounding variables, combined in separate models for each indicator. Some of these variables, however, remained associated with functional capacity. It is considered that the study of oral health status of elderly, associeted with the search for an association with functional capacity is important in the construction of indicators necessary for planning preventive and therapeutic interventions that reduce the risk for loss of ability in daily physical functions and their consequences, as the harm in the oral self-care

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Parenting styles concern overall interaction characteristics between parents and children. To assess them, it is important to build and adapt valid and reliable instruments. The main objectives of this dissertation were to translate, adapt and evaluate the psychometric properties of the Young Parenting Inventory (YPI) for the Brazilian context, as seek associations between the YPI and Familiogram Test (FG). In current study, YPI was adapted to Portuguese by backtranslation method. Content analyses were made by five judges. 920 high school and college students (543 females), whose ages were between 14 and 69 years (M = 21.3, SD = 6.1), filled out the research instruments. Data were collected in Natal, Petrolina and Brasilia cities and Porto Alegre metropolitan region. The results confirmed the existence of five factors. Final version of the YPI was composed by 49 items. Exploratory factorial analysis (principal components) were conducted using oblimin rotation. Five factors extracted explained 45.12% of the maternal scale variance and 47.59% of paternal scale. Each factor explained, at least, 3% of the variance and showed Eigenvalue over than 1.5. All items have factorial loadings values above 0.3. The confirmatory factorial analysis has showed fit statistics reasonably adequate: for maternal scale,  ² [1114] = 4636.38, p < 0.001,  ² / df = 4.16, with GFI = 0.83, AGFI = 0.81 and RMSEA = 0.06; for paternal scale,  ² [1114] = 5133.69 p < 0.001,  ² / df = 4.61, with GFI = 0.81, AGFI = 0.79 and RMSEA = 0,06. Thus, final instrument was composed by the following factors: (I) Disconnection and Rejection ( = 0.89 and 0.90), (II) Affectivity and Emotional Stability ( = 0.85 and 0.88); (III) Overvigilance and Other Directedness ( = 0.83 and 0.85), (IV) Overprotection and Impaired Autonomy ( = 0.78 and 0.79) and (V) Impaired Limits ( = 0.66 and 0.71). Finally, relations between the YPI and FG were assessed. Pearson's correlations between the YPI and FG showed moderated associations, particularly between the factors Affectivity (YPI) and Affection (FG) (r = 0.69 and 0.7 for maternal and paternal scale, respectively); and the factors Disconnection and Rejection (YPI) and Conflict (FG) (r = 0.59 and 0.58). The regression models indicated that over than 40% of variance of factors of FG can be predicted by factors of YPI. Beta coefficients for Affection-Affectivity relation were 0.67 (maternal scale) and 0.53 (paternal scale); for Disconnection-Conflict relation were 0.31 (maternal scale) and 0.44 (paternal scale). We conclude the YPI has adequate psychometric parameters and can be used in future research in this area. However, adjustments in the structure of the YPI were made. Moreover, it is suggested further studies to consider other samples and variables, increasing the knowing of parenting styles and the Young‟s theory in the Brazilian context

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The development of strategies for structural health monitoring (SHM) has become increasingly important because of the necessity of preventing undesirable damage. This paper describes an approach to this problem using vibration data. It involves a three-stage process: reduction of the time-series data using principle component analysis (PCA), the development of a data-based model using an auto-regressive moving average (ARMA) model using data from an undamaged structure, and the classification of whether or not the structure is damaged using a fuzzy clustering approach. The approach is applied to data from a benchmark structure from Los Alamos National Laboratory, USA. Two fuzzy clustering algorithms are compared: fuzzy c-means (FCM) and Gustafson-Kessel (GK) algorithms. It is shown that while both fuzzy clustering algorithms are effective, the GK algorithm marginally outperforms the FCM algorithm. (C) 2008 Elsevier Ltd. All rights reserved.

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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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The general objective of this study is the identification of rural spaces in Rio Grande do Norte through a territorial approach. It looks if there is spatial correlations between municipalities that influence and are influenced by the rural environment, allowing the identification of clusters. To accomplish this objective it`s used, in the methodology, the factor analysis of principal components to achieve the indicators of rurality and territorial development, that deal with four dimensions of analysis: environmental, political-institutional, economical and spatial. Moreover, to identify the spatial correlations structure between municipalities it used the Moran index to both rurality and territorial development, leading to clustering identification. The results show that the rurality is present in most of Rio Grande do Norte municipalities, except in cases like Mossoró, Pau dos Ferros, Caicó and Natal, where can be regional dynamic poles. It is also verified that the more rural municipalities tend to be less developed, according to the territorial development index, and have less correlations with neighboring municipalities

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Lithraea molleoides(Vell.) (Anacardiaceae) é uma árvore encontrada no Brasil, Paraguai, Bolívia, Uruguai, Argentina e Chile. É popularmente usada na forma de extrato alcoólico, decocção e infusão para o tratamento de tosse, bronquite, artrite, doenças do sistema digestivo, como diurético, tranqüilizante, hemostático e tônico. O objetivo do presente estudo foi a extração do óleo essencial dos frutos maduros, folhas e outras partes aéreas da planta e o rendimento do mesmo; a identificação e quantificação dos principais componentes e a determinação da atividade antimicrobiana. O rendimento do óleo essencial dos frutos maduros foi de 1%, entretanto, não foi encontrado óleo essencial nas partes aéreas da planta. A análise do óleo essencial por cromatografia gasosa com espectrometria de massa, mostrou a presença de limoneno (89,89%), alfa-pineno (3,48%), beta-pineno (2,63%), alfa-terpineol (1.27%), mirceno (0,64%), sabineno (0,54%), 4-terpineol (0,28%), canfeno (0,22%) e delta-3-careno (0,13%). O óleo essencial foi ativo contra algumas bactérias Gram positivas e leveduras testadas e não apresentou atividade contra bactérias Gram negativas.

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Sessenta e nove acessos de Psidium, coletados em seis estados brasileiros, foram analisados para dois métodos não hierárquicos de agrupamento e por componentes principais (CP), visando orientar programas de melhoramento. Foram analisadas as variáveis ácido ascórbico, β-caroteno, licopeno, fenóis totais, flavonóides totais, atividade antioxidante, acidez titulável, sólidos solúveis, açúcares solúveis totais, teor de umidade, diâmetro lateral e transversal do fruto, peso da polpa e das sementes/fruto, número e produção de frutos/planta. Foram observados agrupamentos específicos para os acessos de araçazeiros no método de Tocher e do k-means e na dispersão tridimensional dos quatro CPs. Os acessos de araçazeiros foram separados dos de goiabeira. Não foi observado nenhum agrupamento específico por estado de coleta, indicando a inexistência de barreiras na propagação dos acessos de goiabeira. As análises sugerem a prospecção de maior número de amostras de germoplasma num menor número de regiões, bem como acessos divergentes com alto teor de compostos nutricionais.

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

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A análise da interação genótipo x ambiente utilizda no melhoramento de plantas tem sofrido mudanças na última década, melhorando a sua eficiência quanto à seleção dos genótipos sob diferentes condições ambientais. O objetivo deste trabalho foi analisar a produtividade e estabilidade de 12 genótipos de arroz em oito ambientes, durante os anos 2005 e 2006, na Colômbia. O delineamento utilizado foi o de blocos ao acaso com quatro repetições. Os parâmetros de estabilidade fenotípica e o agrupamento dos ambientes foram estimados pelo estudo da interação genótipo x ambiente, segundo o método SREG (Regressão nos sítios ou locais) e seu gráfico biplot (GGE). As análises estatísticas indicaram diferenças significativas (com 5% de probabilidade de erro) entre genótipos e entre ambientes e significância (com 5% de probabilidade de erro) da interação genótipo x ambiente, sugerindo uma resposta diferente dos genótipos nos vários ambientes. No método SREG, os dois primeiros componentes principais da interação explicaram 75,29% da interação. Os genótipos 400094, 350361 e a variedade Fedearroz 50 foram considerados os de maior produtividade. Segundo o gráfico biplot GGE, os ambientes La Libertad e Escobal foram os mais favoráveis para o cultivo do arroz.

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In conformational analysis, the systematic search method completely maps the space but suffers from the combinatorial explosion problem because the number of conformations increases exponentially with the number of free rotation angles. This study introduces a new methodology of conformational analysis that controls the combinatorial explosion. It is based on a dimensional reduction of the system through the use of principal component analysis. The results are exactly the same as those obtained for the complete search but, in this case, the number of conformations increases only quadratically with the number of free rotation angles. The method is applied to a series of three drugs: omeprazole. pantoprazole, lansoprazole-benzimidazoles that suppress gastric-acid secretion by means of H(+), K(+)-ATPase enzyme inhibition. (C) 2002 John Wiley Sons. Inc.

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A quantitative structure-activity relationship (QSAR) study of 19 quinone compounds with trypanocidal activity was performed by Partial Least Squares (PLS) and Principal Component Regression (PCR) methods with the use of leave-one-out crossvalidation procedure to build the regression models. The trypanocidal activity of the compounds is related to their first cathodic potential (Ep(c1)). The regression PLS and PCR models built in this study were also used to predict the Ep(c1) of six new quinone compounds. The PLS model was built with three principal components that described 96.50% of the total variance and present Q(2) = 0.83 and R-2 = 0.90. The results obtained with the PCR model were similar to those obtained with the PLS model. The PCR model was also built with three principal components that described 96.67% of the total variance with Q(2) = 0.83 and R-2 = 0.90. The most important descriptors for our PLS and PCR models were HOMO-1 (energy of the molecular orbital below HOMO), Q4 (atomic charge at position 4), MAXDN (maximal electrotopological negative difference), and HYF (hydrophilicity index).

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We studied ontogenetic variation in the shape of the skull among species of Caiman using principal component analysis. Comparison of multivariate allometric coefficients and ontogenetic trends between size and shape reveals that C. sclerops and C. yacare have similar ontogenetic processes, and they are more related to each other than either is to C. latirostris. Allometric relationships of the characters measured are similar in all species studied. The greater differences were in the width measurements, with higher coefficients in shape (second principal component) for C. latirostris, and length measurements with higher coefficients in shape for C. yacare and C. sclerops. The ontogenetic process leading to change in skull shape in the group seems to be plesiomorphic for elongation and derived for broadening. Statistical comparison of the ontogenetic trends with models of allometric heterochrony suggests that C. latirostris has diverged from the other species by a neotenic process, and that C. sclerops is separated from C. yacare by ontogenetic scaling (progenesis).