910 resultados para multiple regression analysis


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A universidade é um local de aprendizagem no qual conhecimento acadêmico, social e cultural permeia a relação entre os estudantes, onde estes terão a oportunidade de vivenciar diferentes situações durante o curso. A maior preocupação é como esta experiência influenciará o estado nutricional com a possível mudança dos hábitos cotidianos, como abuso de bebidas alcoólicas, uso irrestrito de suplementos vitamínicos e alimentares e a alimentação inadequada. O consumo alimentar de universitários foi o foco desta pesquisa que teve como objetivo geral identificar as principais mudanças do consumo de alimentos/ bebidas e estilos de vida por meio de estudo de coorte, envolvendo estudantes ingressantes nos cursos de graduação da Escola Superior de Agricultura \"Luiz de Queiroz\" - ESALQ/USP, e como objetivos específicos desenvolver, validar e aplicar um instrumento com a finalidade de identificar medidas comportamentais relacionadas aos hábitos de consumo alimentar, atividade física, situação socioeconômica e relacionar as informações obtidas ao estado nutricional do estudante; descrever o consumo dentro e fora do domicílio. Participaram da pesquisa estudantes com idade entre 18 e 30 anos. Um questionário foi aplicado juntamente com a avaliação antropométrica para mensuração do peso, altura e classificação do estado nutricional por meio do Índice de Massa Corporal (IMC). Este protocolo foi repetido após 8 meses de curso para que fosse identificada a situação do estado nutricional de cada indivíduo relacionada às mudanças do comportamento alimentar. Os dados coletados foram armazenados em base de dados no Microsoft Excel, sendo analisados por meio do Statistical Analysis System. Os dados quantitativos foram expressos em média e desvio-padrão (DP) com cálculos de intervalos de confiança de 95%. O teste do qui-quadrado foi utilizado para comparar a distribuição da prevalência de sobrepeso e obesidade quanto à variável sexo, associando-se ao IMC. Foi utilizado o coeficiente de correlação intraclasse de Pearson para verificação de concordância entre peso e altura aferidos e referidos. Foi realizada análise de regressão múltipla para identificação da mudança de consumo entre as fases, assim como para peso corporal. Utilizou-se o nível de significância de 5%. Observaram-se entre as duas fases quantidades preocupantes de nutrientes ingeridos aquém ou além dos limites preconizados para ambos os sexos; destaque para o elevado consumo de sódio, e insatisfatório de carotenóides. No caso dos carotenóides, houve crescimento significativo da contribuição da categoria 3 para as alunas. O consumo de cafeína na segunda fase foi maior, predominando o fornecimento pelos alimentos ultraprocessados. De forma geral houve aumento do consumo de alimentos processados e ultraprocessados. Observou-se aumento (significativo a 5%) no consumo de lipídios. Constatou-se diminuição na prática de exercícios físicos e aumento na ingestão de bebidas alcoólicas, e destas com energéticos e no tabagismo. Concluiu-se que o ingresso na universidade contribui para a mudança nos hábitos alimentares e estilos de vida de maneira negativa, sendo necessária intervenção adequada visando a promoção da saúde dos estudantes.

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The literature states that project duration is affected by various scope factors. Using 168 building projects carried out in Spain, this paper uses the multiple regression analysis to develop a forecast model that allows estimating project duration of new builds. The proposed model uses project type, gross floor area (GFA), the cost/GFA relationship and number of floors as predictor variables. The research identified the logarithmic form of construction speed as the most appropriate response variable. GFA has greater influence than cost on project duration but both factors are necessary to achieve a forecast model with the highest accuracy. We developed an analysis to verify the stability of forecasted values and showed how a model with high values of fit and accuracy may display an anomalous behavior in the forecasted values. The sensitivity of the proposed forecast model was also analyzed versus the variability of construction costs.

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Purpose: To evaluate the correlation of the mean curvature and shape factors of both corneal surfaces for different corneal diameters measured with the Scheimpflug photography–based system in keratoconus eyes. Methods: A total of 61 keratoconus eyes of 61 subjects, aged 14 to 64 years, were included in this study. All eyes received a comprehensive ophthalmologic examination including anterior segment and corneal analysis with the Sirius system (CSO): anterior and posterior mean corneal radius for 3, 5, and 7 mm (aKM, pKM), anterior and posterior mean shape factor for 4.5 and 8 mm (ap, pp), central and minimal corneal thickness, and anterior chamber depth. Results: Mean aKM/pKM ratio around 1.20 (range, 0.95–1.48) was found for all corneal diameters (P = 0.24). Weak but significant correlations of this ratio with pachymetric parameters were found (r between −0.28 and −0.34, P < 0.04). The correlation coefficient between aKM and pKM was ≥0.92 for all corneal diameters. A strong and significant correlation was also found between ap and pp (r ≥ 0.86, P < 0.01). The multiple regression analysis revealed that central pKM was significantly correlated with aKM, central corneal thickness, anterior chamber depth, and spherical equivalent (R2 ≥ 0.88, P < 0.01) and that 8 mm pp was significantly correlated with 8 mm ap and age (R2 = 0.89, P < 0.01). Conclusions: Central posterior corneal curvature and shape factor in the keratoconus eye can be consistently predicted from the anterior corneal curvature and shape factor, respectively, in combination with other anatomical and ocular parameters.

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AIM: To evaluate the prediction error in intraocular lens (IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP). METHODS: Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany). In all cases, an adjusted IOL power (PIOLadj) was calculated based on Gaussian optics using a variable keratometric index value (nkadj) for the estimation of the corneal power (Pkadj) and on a new value for ELP (ELPadj) obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal) and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay). RESULTS: PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05). In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D) and limits of agreement (of 1.47 and -1.61 D) when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01) and was found to be dependent on axial length, anterior chamber depth and Pkadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.

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Purpose: To evaluate the predictability of the refractive correction achieved with a positional accommodating intraocular lenses (IOL) and to develop a potential optimization of it by minimizing the error associated with the keratometric estimation of the corneal power and by developing a predictive formula for the effective lens position (ELP). Materials and Methods: Clinical data from 25 eyes of 14 patients (age range, 52–77 years) and undergoing cataract surgery with implantation of the accommodating IOL Crystalens HD (Bausch and Lomb) were retrospectively reviewed. In all cases, the calculation of an adjusted IOL power (PIOLadj) based on Gaussian optics considering the residual refractive error was done using a variable keratometric index value (nkadj) for corneal power estimation with and without using an estimation algorithm for ELP obtained by multiple regression analysis (ELPadj). PIOLadj was compared to the real IOL power implanted (PIOLReal, calculated with the SRK-T formula) and also to the values estimated by the Haigis, HofferQ, and Holladay I formulas. Results: No statistically significant differences were found between PIOLReal and PIOLadj when ELPadj was used (P = 0.10), with a range of agreement between calculations of 1.23 D. In contrast, PIOLReal was significantly higher when compared to PIOLadj without using ELPadj and also compared to the values estimated by the other formulas. Conclusions: Predictable refractive outcomes can be obtained with the accommodating IOL Crystalens HD using a variable keratometric index for corneal power estimation and by estimating ELP with an algorithm dependent on anatomical factors and age.

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Research on the impact of innovation on regional economic performance in Europe has fundamentally followed three approaches: a) the analysis of the link between investment in R&D, patents, and economic growth; b) the study of the existence and efficiency of regional innovation systems; and c) the examination of geographical diffusion of regional knowledge spillovers. These complementary approaches have, however, rarely been combined. Important operational and methodological barriers have thwarted any potential cross-fertilization. In this paper, we try to fill this gap in the literature by combining in one model R&D, spillovers, and innovation systems approaches. A multiple regression analysis is conducted for all regions of the EU-25, including measures of R&D investment, proxies for regional innovation systems, and knowledge and socio-economic spillovers. This approach allows us to discriminate between the influence of internal factors and external knowledge and institutional flows on regional economic growth. The empirical results highlight how the interaction between local and external research with local and external socioeconomic and institutional conditions determines the potential of every region in order to maximise its innovation capacity. They also indicate the importance of proximity for the transmission of economically productive knowledge, as spillovers show strong distance decay effects. In the EU-25 context, only the innovative efforts pursued within a 180 minute travel radius have a positive and significant impact on regional growth performance.

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In order to reconstruct past variations in the aeolian dust (Kosa) contribution to the Japan Sea, and to establish a direct link between terrestrial and marine climatic records, we have applied statistical procedures to distinguish and quantify detrital subcomponents within the detrital fraction of the late Quaternary hemipelagic sediments in the Japan Sea. Q-mode factor analysis with varimax and oblique rotation of the factors followed by multiple-regression analysis between mineral composition and factor loadings was conducted using six ''detrital'' elements. Four detrital subcomponents were defined, which are attributed to Kosa derived from ''typical'' loess, Kosa from ''weathered'' loess, and fine and coarse arc-derived detritus, respectively, based on comparisons with the chemical and mineral compositions of probable source materials. Using these detrital subcomponents, the variation in Kosa fraction was reconstructed for the last 200 ky. The results reveal millennial-scale as well as glacial-interglacial scale variations in Kosa contribution. Especially, millennial-scale variability of Kosa contribution suggests the presence of high frequency variation in summer monsoon precipitation in the central to east Asia during the last 200 ky.

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Thesis (Master's)--University of Washington, 2016-06

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Aims: To investigate the prevalence of vitamin A deficiency among lactating women in a poor urban population of Bangladesh, and to examine the relationship between various factors and vitamin A status. Design: Cross-sectional study. Setting: Maternal and child health clinic in Dhaka City, Bangladesh. Subjects and methods: A total of 120 lactating women aged 17-37 years were randomly selected from women who attended a local maternal and child health clinic in Dhaka City for immunisation of their children. Various socio-economic, personal characteristics, dietary intakes of vitamin A and anthropometric data were collected. Serum retinol (vitamin A) concentration was determined as a measure of vitamin A status. Results: Of the subjects, 37% had low serum vitamin A levels (<30 μg dl(-1)), with 13.3% having sub-clinical vitamin A deficiency (<20 mug dl(-1)). Eighty-seven per cent had vitamin A intakes below the recommended dietary allowance. The lactating women who were either illiterate or received only informal education had significantly (P=0.002) lower serum vitamin A levels compared with those who received formal education. The women whose husbands received formal education had significantly (P=0.05) higher serum vitamin A levels than those whose husbands were either illiterate or received only informal education. The serum vitamin A levels of women in households with poor sanitation/latrine practice were significantly (P=0.03) lower than those of women in households with good sanitation/latrine practice. The women with one child had significantly (P=0.015) lower serum vitamin A levels than those with two or more children. Women with a lactation period of 6 months or more had significantly (P=0.034) lower serum vitamin A levels than women with a lactation period of less than 6 months. The women who consumed less than the median vitamin A intake (274.8 mug day(-1)) had significantly (P=0.01) lower serum vitamin A levels than those who consumed more than the median vitamin A intake. By multiple regression analysis, education level of the women, number of living children, duration of lactation and dietary intake of vitamin A were found to have significant independent relationships with serum vitamin A. The overall F-ratio (6.8) was highly significant (P=0.000), the adjusted R-2 was 0.16 (multiple R=0.44). Conclusion: A significant proportion of poor, urban, lactating women in Bangladesh have vitamin A deficiency. Among the various factors, education level of the women, number of living children, duration of lactation and dietary intake of vitamin A appear to be important in influencing the vitamin A status of these women.

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This cross-sectional study investigated the prevalence of anaemia and vitamin A deficiency (VAD) among pregnant women in a poor urban population of Bangladesh. It also examined the association of various socio-economic and dietary factors with anaemia and vitamin A status. A maternal and child health clinic in Dhaka city, Bangladesh was used to obtain the sample. Three hundred and eighty three pregnant women, aged 20-30 years, of 20-30 weeks gestation were randomly selected from women on their first presentation for antenatal care. Socio-economic, pregnancy related information, usual dietary pattern, and anthropometric data were collected. Blood haemoglobin and serum retinol (vitamin A) concentrations were determined. About 40% of the pregnant women were anaemic (haemoglobin <11.0 g/dl) and 45% had low serum vitamin A levels (<30 mug/dl); with 8.6% having sub-clinical VAD (serum retinol <20 μg/dl). The women with low serum vitamin A levels had 1.8 times greater risk of being anaemic than did the women with normal vitamin A status. Food frequency data revealed that a large proportion of these women did not consume egg (49%), milk (25%), meat (31%), liver (83%), large fish (32%), small fish (39%) and sweet pumpkin (52%) at all; while about 25% of the women reported consuming dark green leafy vegetables (DGLV) and 64% reported an intake of fruit at least four servings a week. The pregnant women who were either illiterate or received only informal education (up to grade ten) had significantly lower haemoglobin and serum vitamin A levels compared to those who completed at least a secondary school certificate. The women whose husbands were illiterate or received only informal education had significantly (P=0.01) lower serum vitamin A levels than those whose husbands had received at least a secondary school certificate. The women who came from families with a per-capita income below the poverty line had significantly lower haemoglobin and serum vitamin A levels compared to those who came from families with a per-capita income above the poverty line. The women who consumed three servings or less of DGLV and fruit per week had significantly lower haemoglobin and serum vitamin A levels than those who consumed four or more servings a week. The women who never consumed large fish had significantly lower haemoglobin compared to those who reported at least one serving a week. Furthermore, the women who never consumed sweet pumpkin had significantly lower serum vitamin A than the women who ate at least one serving a week. By multiple regression analysis, intake of meat, DGLV and fruit, and serum vitamin A levels were found to have a significant independent relationship with haemoglobin. The overall F-ratio (9.9) was highly significant (P=0.000), the adjusted R-square was 0.086 (multiple R=0.309). Multiple regression analysis for serum vitamin A also revealed a significant independent relationship with per capita income, haemoglobin levels, intakes of DGLV and sweet pumpkin. The overall F-ratio (10.2) was highly significant (P=0.000), the adjusted R-square was 0.10 (multiple R=0.312). In conclusion, anaemia and vitamin A deficiency were highly prevalent among poor urban pregnant women in Bangladesh. Various socio-economic and dietary factors may influence the anaemia and vitamin A status of these women. The present study emphasizes the need for a comprehensive intervention strategy, which include both nutritional and environmental factors, to improve the nutritional status of this population.

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This study presents the first analysis of the impact of NASCAR sponsorship announcements on the stock prices of sponsoring firms. The primary finding of the study-that NASCAR sponsorship announcements were accompanied by the largest increases in shareholder wealth ever recorded in the marketing literature in response to a voluntary marketing program-represents a striking and unambiguous stock market endorsement of the sponsorships. Indeed, the 24 sponsors analyzed in this study experienced mean increases in shareholder wealth of over $300 million dollars, net of all of the costs associated with the sponsorships. A multiple regression analysis of firm-specific stock price changes and select corporate and sponsorship attributes indicates that NASCAR sponsorships with more successful racing teams, corporate (as opposed to product or divisional) sponsorships, and sponsorships with direct ties to the consumer automotive industry are all positively correlated with perceived sponsorship success, while corporate cash flow per share (a well-known proxy for agency conflicts within the firm) is negatively related with shareholder approval.

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In recognition of a central role of the kidney in long-term blood pressure control, we undertook an in-depth analysis of the relationship between blood pressure and kidney damage caused by environmental exposure to the common pollutants cadmium and lead. The subjects were 200 healthy Thais, 16 and 60 years of age (100 female non-smokers, 53 male non-smokers, and 47 male smokers). None of these subjects had been exposed to Cd or Pb in the workplace and their urinary Cd concentrations ranged from 0.4 to 37 nM, whereas their urinary Pb concentrations ranged from 0.1 to 30 nM. The prevalence of high blood pressure was 2%, 8% and 19%, respectively in subjects with low, average and high Cd-burden (linear trend chi(2) = 6.4, P = 0.01). Multiple regression analysis revealed a significant positive association between Cd-burden and blood pressure in male nonsmokers (adjusted beta = 0.31, P = 0.02) and an inverse association between blood pressure and urinary Pb excretion rate in male smokers (adjusted beta = -0.38, P = 0.005). Associations between Cd-burden and nephropathies were evidenced by increases in urinary excretion of beta 2-microglobutin (P = 0.02) and N-acetyl-beta-D-glucosaminidase (P = 0.005) in subjects with high Cd-burden, compared with the subjects with average Cd-burden. In addition, an association between Cd-related nephropathy and high blood pressure was evidenced by a 20% increase in the prevalence of high blood pressure in people with NAG-uria (linear trend chi(2) = 4.3, P = 0.04). Our present study provides first evidence for a possible link between renal tubular damage and dysfunction caused by environmental Cd exposure and increased risk of high blood pressure. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

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Background: The objective was to determine whether the pattern of environmental and genetic influences on deviant personality scores differs from that observed for the normative range of personality, comparing results in adolescent and adult female twins. Methods: A sample of 2,796 female adolescent twins ascertained from birth records provided Junior Eysenck Personality Questionnaire data. The average age of the sample was 17.0 years ( S. D. 2.3). Genetic analyses of continuous and extreme personality scores were conducted. Results were compared for 3,178 adult female twins. Results: Genetic analysis of continuous traits in adolescent female twins were similar to findings in adult female twins, with genetic influences accounting for between 37% and 44% of the variance in Extraversion (Ex), Neuroticism (N), and Social Non-Conformity (SNC), with significant evidence of shared environmental influences (19%) found only for SNC in the adult female twins. Analyses of extreme personality characteristics, defined categorically, in the adolescent data and replicated in the adult female data, yielded estimates for high N and high SNC that deviated substantially (p < .05) from those obtained in the continuous trait analyses, and provided suggestive evidence that shared family environment may play a more important role in determining personality deviance than has been previously found when personality is viewed continuously. However, multiple-threshold models that assumed the same genetic and environmental determinants of both normative range variation and extreme scores gave acceptable fits for each personality dimension. Conclusions: The hypothesis of differences in genetic or environmental factors responsible for N and SNC among female twins with scores in the extreme versus normative ranges was partially supported, but not for Ex.

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This study assessed the theory of mind (ToM) and executive functioning (EF) abilities of 124 typically developing preschool children aged 3 to 5 years in relation to whether or not they had a child-aged sibling (i.e. a child aged 1 to 12 years) at home with whom to play and converse. On a ToM battery that included tests of false belief, appearance-reality (AR) and pretend representation, children who had at least 1 child-aged sibling scored significantly higher than both only children and those whose only siblings were infants or adults. The numbers of child-aged siblings in preschoolers' families positively predicted their scores on both a ToM battery (4 tasks) and an EF battery (2 tasks), and these associations remained significant with language ability partialled out. Results of a hierarchical multiple regression analysis revealed that independent contributions to individual differences in ToM were made by language ability, EF skill and having a child-aged sibling. However, even though some conditions for mediation were met, there was no statistically reliable evidence that EF skills mediated the advantage of presence of child-aged siblings for ToM performance. While consistent with the theory that distinctively childish interaction among siblings accelerates the growth of both TOM and EF capacities, alternative evidence and alternative theoretical interpretations for the findings were also considered.

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Atualmente, características organizacionais vêm sendo estudadas sob um prisma diferenciado. Hoje, são pesquisados com maior ênfase os aspectos positivos que possam prover a possibilidade dos trabalhadores nutrirem sentimentos positivos para com suas organizações empregadoras e ao seu trabalho propriamente dito. Os desafios impostos atualmente giram em torno de se buscar identificar características organizacionais positivas que permitam o florescimento do trabalhador. Tais características são postuladas como benéficas tanto às organizações, por resultar em maior produtividade e lucratividade, assim como para promover o bem-estar dos trabalhadores. O objetivo deste estudo foi analisar os impactos que as dimensões da organização positiva exercem sobre o bem-estar dos trabalhadores. O bem-estar dos trabalhadores foi dividido em duas áreas, bem-estar subjetivo (composto por satisfação geral com a vida, afetos positivos e afetos negativos) e bem-estar no trabalho, composto por três dimensões: satisfação no trabalho, envolvimento com o trabalho e comprometimento organizacional afetivo. Organização positiva foi concebida como um construto composto por três dimensões: percepção de suporte organizacional, percepções de justiça organizacional (distributiva e de procedimentos) e confiança do empregado na organização. A amostra foi composta por 200 trabalhadores de diversas empresas do Estado de São Paulo, sendo 55 do sexo masculino e 145 do sexo feminino, solteiros e casados com escolaridade distribuída desde o ensino fundamental completo até pósgraduação completa. O instrumento de coleta de dados foi um questionário auto-aplicável composto por nove escalas que mediram as variáveis do estudo. Os resultados deste trabalho revelaram que bem-estar subjetivo e bem-estar no trabalho guardam relações entre si. Análises de regressão múltipla informaram que as dimensões da organização positiva tiveram impactos maiores sobre bem-estar no trabalho do que bem-estar subjetivo, destacando-se a capacidade de confiança do empregado na organização de prover explicações para o bem-estar de trabalhadores, seja nos domínios da vida pessoal ou no contexto de trabalho. Conforme tais resultados, confiança do empregado na organização, percepções de justiça e de suporte organizacional poderiam ser apontadas como importantes dimensões da organização positiva para promover e proteger o bem-estar dos trabalhadores. Futuros estudos deveriam incluir outras características organizacionais positivas para aumentar a explicação da variância do bem-estar dos trabalhadores