Modelo matemático para predição do VO2máx em cicloergômetro baseado na análise dos gases expirados

Existem diversas equações para predição do VO2máx a partir de variáveis dentro do teste ergométrico em vários ergômetros, no entanto equação semelhante utilizando os limiares ventilatórios na ergoespirometria em teste sub-máximo no cicloergômetro não está disponível. O objetivo do presente estudo foi avaliar a precisão de modelos de predição do VO2máx com base em indicadores de esforço sub-máximo. Neste sentido foram testados em protocolo incremental máximo no cicloergômetro 7.877 voluntários, sendo 4640 indivíduos do sexo feminino e 3147 do sexo masculino, todos saudáveis não atletas, com idades acima de 20 anos, divididos randomicamente em dois grupos: A de estimação e B de validação. A partir das variáveis independentes massa corporal (MC) em kg, carga de trabalho no limiar 2 (WL2) e freqüência cardíaca no limiar 2 (FCL2) foi possível construir um modelo de regressão linear múltipla para predição do VO2máx. Os resultados demonstram que em indivíduos saudáveis não atletas de ambos os sexos é possível predizer o VO2máx com um erro mínimo (EPE = 1,00%) a partir de indicadores submáximos obtidos em teste incremental. O caráter multidisciplinar do trabalho pôde ser caracterizado pelo emprego de técnicas que envolveram pneumologia, educação física, fisiologia e estatística

A influência da adição de caulim, quartzo e feldspato potássico na formulação de massas cerâmicas para telhas: Modelo estatístico

The production of roof tiles in the state of Rio Grande do Norte accounts for around 60% of the total of ceramic pieces produced. There is a need for investment to improve quality and productivity, thereby promoting technological innovations. Accordingly, the aim of this study is to determine the effect of kaolin, potassium feldspar and quartz in two standard formulations, as well as the effect of sintering temperature on the technological properties of linear firing shrinkage, water absorption and bending rupture stress, by fitting the statistical model and using multiple linear regression to assess the relationship between technological properties and independent variables. The raw materials were characterized using the following techniques: X-ray fluorescence (XRF), X-ray diffraction (XRF), rational analysis (RA), differential thermal analysis (DTA) and granulometric analysis (GA). The test specimens were compacted by uniaxial pressure (25 MPa), dried in a stove at 110 ºC for 24 hours and sinterized at 850 ºC, 950 ºC and 1050 ºC and held isothermal for 30 minutes. The results obtained indicate that the addition of kaolin to two standard formulations (M and R) promoted a reduction in water absorption values and an increase in bending rupture stress values. The sintering temperatures for group M that resulted in the lowest linear firing shrinkage and water absorption values were 850 ºC and 950 ºC, respectively, and the highest bending rupture stress values were reached at a temperature of 950 ºC. In the case of group R, the sintering temperature that obtained the lowest water absorption and linear firing shrinkage values was 850 ºC, and the highest bending rupture stress values were attained at a temperature of 1050 ºC. This work explains the statistical approach used to fit the model that describes the relationship between the technological properties and percentage of kaolin, quartz and feldspar, as well as the models that enable predictions, provided that the lower and upper limits of the percentage of clay minerals, flux and quartz used in this study are respected. Statistica 6 software was used and results were obtained by stepwise forward regression

Sistema inteligente para estimar a porosidade em sedimentos a partir da análise de sinais GPR

This Thesis presents the elaboration of a methodological propose for the development of an intelligent system, able to automatically achieve the effective porosity, in sedimentary layers, from a data bank built with information from the Ground Penetrating Radar GPR. The intelligent system was built to model the relation between the porosity (response variable) and the electromagnetic attribute from the GPR (explicative variables). Using it, the porosity was estimated using the artificial neural network (Multilayer Perceptron MLP) and the multiple linear regression. The data from the response variable and from the explicative variables were achieved in laboratory and in GPR surveys outlined in controlled sites, on site and in laboratory. The proposed intelligent system has the capacity of estimating the porosity from any available data bank, which has the same variables used in this Thesis. The architecture of the neural network used can be modified according to the existing necessity, adapting to the available data bank. The use of the multiple linear regression model allowed the identification and quantification of the influence (level of effect) from each explicative variable in the estimation of the porosity. The proposed methodology can revolutionize the use of the GPR, not only for the imaging of the sedimentary geometry and faces, but mainly for the automatically achievement of the porosity one of the most important parameters for the characterization of reservoir rocks (from petroleum or water)

Avaliação multidimensional da qualidade de vida em idosos: um estudo no Curimataú ocidental paraibano

The fast growth of the elderly population is a reality throughout the world and has become one of the greatest challenges for contemporary public health. When considering the increased life expectancy and the aging as a multidimensional phenomenon, one should highlight the need to investigate if the increase of longevity is associated with satisfactory levels of Quality of Life (QOL). This study has the objective of assessing the QOL of elderly people from the Paraíba’s Western Curimataú microregion, explained by its health and living conditions. This is a cross-sectional and observational study with quantitative design held with 444 elderly people from five cities: Barra de Santa Rosa, Cuité, Nova Floresta, Remígio e Sossego. In order to obtain information, the following instruments were used: I) Questionnaire for collection data related to the elderly population, for sociodemographic, clinical and behavioral characteristics; and II) WHOQOL-Old questionnaire, with a view to measuring and assessing QOL. Data were processed on the IBM-SPSS Statistics 20.0 software by means of the ANOVA (one-way), Student’s t, Mann-Whitney, Kruskal-Wallis and Pearson’s correlation tests, with p-values<0,05 accepted as being statistically significant. The results indicate a good global QOL (ETT=65,69%), with better assessment by elderly men, aged between 60 and 74 years, married, living with partner and children, without caregiver, physical activity practitioners, with up to one health problem before an aspect of multimorbidity and with very good and/or good assessment of basic needs. The self-reported stress showed a negative significant correlation before the global QOL, where the greater the perception of stress, the worse the assessment of QOL. In the faceted assessment of QOL, the Sensory Operation showed the best performance (ETF= 68,86%) and the Social Participation (SP) the worst (ETF=60,37%). In the multiple linear regression model, SP is singly responsible for 51,8% (R2=0,518) of explanation of the global QOL. In the intercorrelation among the WHOQOL-Old facets, only Death and Dying did not reveal significance. The harmony highlighted among the facets raises the need to ensure a comprehensive health care for the elderly population, especially in understanding the social participation as an intrinsic part of the QOL and that it requires the re-discussion and reconstruction of individual and collective, family and community, political and government actions. Hence, guaranteeing an active, healthy and participatory aging, with QOL, is the major challenge.

Avaliação multidimensional da qualidade de vida em idosos: um estudo no Curimataú ocidental paraibano

The fast growth of the elderly population is a reality throughout the world and has become one of the greatest challenges for contemporary public health. When considering the increased life expectancy and the aging as a multidimensional phenomenon, one should highlight the need to investigate if the increase of longevity is associated with satisfactory levels of Quality of Life (QOL). This study has the objective of assessing the QOL of elderly people from the Paraíba’s Western Curimataú microregion, explained by its health and living conditions. This is a cross-sectional and observational study with quantitative design held with 444 elderly people from five cities: Barra de Santa Rosa, Cuité, Nova Floresta, Remígio e Sossego. In order to obtain information, the following instruments were used: I) Questionnaire for collection data related to the elderly population, for sociodemographic, clinical and behavioral characteristics; and II) WHOQOL-Old questionnaire, with a view to measuring and assessing QOL. Data were processed on the IBM-SPSS Statistics 20.0 software by means of the ANOVA (one-way), Student’s t, Mann-Whitney, Kruskal-Wallis and Pearson’s correlation tests, with p-values<0,05 accepted as being statistically significant. The results indicate a good global QOL (ETT=65,69%), with better assessment by elderly men, aged between 60 and 74 years, married, living with partner and children, without caregiver, physical activity practitioners, with up to one health problem before an aspect of multimorbidity and with very good and/or good assessment of basic needs. The self-reported stress showed a negative significant correlation before the global QOL, where the greater the perception of stress, the worse the assessment of QOL. In the faceted assessment of QOL, the Sensory Operation showed the best performance (ETF= 68,86%) and the Social Participation (SP) the worst (ETF=60,37%). In the multiple linear regression model, SP is singly responsible for 51,8% (R2=0,518) of explanation of the global QOL. In the intercorrelation among the WHOQOL-Old facets, only Death and Dying did not reveal significance. The harmony highlighted among the facets raises the need to ensure a comprehensive health care for the elderly population, especially in understanding the social participation as an intrinsic part of the QOL and that it requires the re-discussion and reconstruction of individual and collective, family and community, political and government actions. Hence, guaranteeing an active, healthy and participatory aging, with QOL, is the major challenge.

Sistema inteligente para estimar a porosidade em sedimentos a partir da análise de sinais GPR

This Thesis presents the elaboration of a methodological propose for the development of an intelligent system, able to automatically achieve the effective porosity, in sedimentary layers, from a data bank built with information from the Ground Penetrating Radar GPR. The intelligent system was built to model the relation between the porosity (response variable) and the electromagnetic attribute from the GPR (explicative variables). Using it, the porosity was estimated using the artificial neural network (Multilayer Perceptron MLP) and the multiple linear regression. The data from the response variable and from the explicative variables were achieved in laboratory and in GPR surveys outlined in controlled sites, on site and in laboratory. The proposed intelligent system has the capacity of estimating the porosity from any available data bank, which has the same variables used in this Thesis. The architecture of the neural network used can be modified according to the existing necessity, adapting to the available data bank. The use of the multiple linear regression model allowed the identification and quantification of the influence (level of effect) from each explicative variable in the estimation of the porosity. The proposed methodology can revolutionize the use of the GPR, not only for the imaging of the sedimentary geometry and faces, but mainly for the automatically achievement of the porosity one of the most important parameters for the characterization of reservoir rocks (from petroleum or water)

Uma perspectiva de extensão do modelo de aceitação de tecnologia para explicar o uso de linguagens de desenvolvimento WEB: pesquisa com desenvolvedores Pyton e Java

The spread of the Web boosted the dissemination of Information Systems (IS) based on the Web. In order to support the implementation of these systems, several technologies came up or evolved with this purpose, namely the programming languages. The Technology Acceptance Model TAM (Davis, 1986) was conceived aiming to evaluate the acceptance/use of information technologies by their users. A lot of studies and many applications have used the TAM, however, in the literature it was not found a mention of the use of such model related to the use of programming languages. This study aims to investigate which factors influence the use of programming languages on the development of Web systems by their developers, applying an extension of the TAM, proposed in this work. To do so, a research was done with Web developers in two Yahoo groups: java-br and python-brasil, where 26 Java questionnaires and 39 Python questionnaires were fully answered. The questionnaire had general questions and questions which measured intrinsic and extrinsic factors of the programming languages, the perceived usefulness, the perceived ease of use, the attitude toward the using and the programming language use. Most of the respondents were men, graduate, between 20 and 30 years old, working in the southeast and south regions. The research was descriptive in the sense of its objectives. Statistical tools, descriptive statistics, main components and linear regression analysis were used for the data analysis. The foremost research results were: Java and Python have machine independence, extensibility, generality and reliability; Java and Python are more used by corporations and international organizations than supported by the government or educational institutions; there are more Java programmers than Python programmers; the perceived usefulness is influenced by the perceived ease of use; the generality and the extensibility are intrinsic factors of programming languages which influence the perceived ease of use; the perceived ease of use influences the attitude toward the using of the programming language

Modelo matemático para otimização dos custos de um sistema híbrido eólico-solar : aplicação no bombeamento de petróleo

This work purposes the application of a methodology to optimize the implantation cost of an wind-solar hybrid system for oil pumping. The developed model is estimated the implantation cost of system through Multiple Linear Regression technique, on the basis of the previous knowledge of variables: necessary capacity of storage, total daily energy demand, wind power, module power and module number. These variables are gotten by means of sizing. The considered model not only can be applied to the oil pumping, but also for any other purposes of electric energy generation for conversion of solar, wind or solar-wind energy, that demand short powers. Parametric statistical T-student tests had been used to detect the significant difference in the average of total cost to being considered the diameter of the wind, F by Snedecor in the variance analysis to test if the coefficients of the considered model are significantly different of zero and test not-parametric statistical by Friedman, toverify if there is difference in the system cost, by being considered the photovoltaic module powers. In decision of hypothesis tests was considered a 5%-significant level. The configurations module powers showed significant differences in total cost of investment by considering an electrical motor of 3 HP. The configurations module powers showed significant differences in total cost of investment by considering an electrical motor of 5 HP only to wind speed of 4m/s and 6 m/s in wind of 3 m, 4m and 5 m of diameter. There was not significant difference in costs to diameters of winds of 3 m and 4m. The mathematical model and the computational program may be used to others applications which require electrical between 2.250 W and 3.750 W. A computational program was developed to assist the study of several configurations that optimizes the implantation cost of an wind-solar system through considered mathematical model

Determinantes da Estrutura de Capital de Companhias Abertas Brasileiras Não-Financeiras: Um Estudo Empírico com Dados em Painel

When a company desires to invest in a project, it must obtain resources needed to make the investment. The alternatives are using firm s internal resources or obtain external resources through contracts of debt and issuance of shares. Decisions involving the composition of internal resources, debt and shares in the total resources used to finance the activities of a company related to the choice of its capital structure. Although there are studies in the area of finance on the debt determinants of firms, the issue of capital structure is still controversial. This work sought to identify the predominant factors that determine the capital structure of Brazilian share capital, non-financial firms. This work was used a quantitative approach, with application of the statistical technique of multiple linear regression on data in panel. Estimates were made by the method of ordinary least squares with model of fixed effects. About 116 companies were selected to participate in this research. The period considered is from 2003 to 2007. The variables and hypotheses tested in this study were built based on theories of capital structure and in empirical researches. Results indicate that the variables, such as risk, size, and composition of assets and firms growth influence their indebtedness. The profitability variable was not relevant to the composition of indebtedness of the companies analyzed. However, analyzing only the long-term debt, comes to the conclusion that the relevant variables are the size of firms and, especially, the composition of its assets (tangibility).This sense, the smaller the size of the undertaking or the greater the representation of fixed assets in total assets, the greater its propensity to long-term debt. Furthermore, this research could not identify a predominant theory to explain the capital structure of Brazilian

Fatores que influenciam a aceitação de práticas avançadas de gestão de segurança da informação: um estudo com gestores públicos estaduais no Brasil

This study examines the factors that influence public managers in the adoption of advanced practices related to Information Security Management. This research used, as the basis of assertions, Security Standard ISO 27001:2005 and theoretical model based on TAM (Technology Acceptance Model) from Venkatesh and Davis (2000). The method adopted was field research of national scope with participation of eighty public administrators from states of Brazil, all of them managers and planners of state governments. The approach was quantitative and research methods were descriptive statistics, factor analysis and multiple linear regression for data analysis. The survey results showed correlation between the constructs of the TAM model (ease of use, perceptions of value, attitude and intention to use) and agreement with the assertions made in accordance with ISO 27001, showing that these factors influence the managers in adoption of such practices. On the other independent variables of the model (organizational profile, demographic profile and managers behavior) no significant correlation was identified with the assertions of the same standard, witch means the need for expansion researches using such constructs. It is hoped that this study may contribute positively to the progress on discussions about Information Security Management, Adoption of Safety Standards and Technology Acceptance Model

Níveis de homocisteína e desempenho cognitivo em uma amostra populacional de idosos da cidade do Natal-RN

The imprecision of the frontier that separates those cognitive deficits inherent to the human physiological aging process from those which represent the early signs of nervous system degenerative pathologies ,very prevalent among the elderly, has brought attention to the need of studies aiming to establish clinical and/or laboratorial criteria to allow this differentiation. Elderly people living in poor and developing countries are frequently exposed to precarious socioeconomic conditions which facilitate the development of an array of pathologies which have metabolic and nutritional dysfunctions as the established or proposed etiological agents. The levels of certain micronutrients, such as the vitamins B12 and B9 (folic acid), and of some intermediary metabolites, such as homocysteine are being thought of as etiological factors and/or as biological markers of a group of alterations which affect the normal functioning of the nervous system with important reflexes upon cognitive performance. This study aims to investigate the influence of homocysteine, B12 vitamin and folic acid levels on the cognitive performance of the low income elderly population. This transversal study took place in Natal, Rio Grande do Norte State, Brazil, and involved 205 dwelling elderly people, users of the Programa de Saúde da Família, a public healthcare program, maintained by the city s health authorities. A multidimensional questionnaire was used to assess the socio-demographic aspects and the overall health and nutrition conditions. The cognitive performance was measured by the use of the Portuguese version of the Mini Mental State Exam (MMSE). The serum levels of homocysteine, B12 vitamin and folic acid were determined by chemiluminescence. The association between the socio-demographic and serum levels of Hcy, B12 vitamin and folic acid was determined by multiple linear regression. Serum levels higher than 13.5 μmol/l, indicative of hyperhomocysteinemia (HHcy), were found on 25.4% of the sample, being more prevalent in men (p<0.05). Deficitary levels of folic acid (<5ng/mol) and of B12 vitamin (<193 pg/ml) were found on 3.9% and 10.2% of the sample respectively. A negative correlation was found between cognitive performance with both age and HHcy and a positive correlation was found between cognitive performance and schooling. The isolated HHcy R2 values were an explanation to only 4% of the variance of the MMSE scores. However, when associated with schooling and age, this model explains about 25% of this association

Consumo familiar: efeitos da valorização do salário mínimo nas decisões de gasto das famílias brasileiras, nordestinas e potiguares, no período de 1995 a 2011

This research objectify to analyze the effects of minimum wage recovery in the household consumption in the Brazil, northeastern region of the Brazil and the state of the Rio Grande do Norte, in the period of 1995 to 2011. This is because the search for the strengthening of the internal market, via incentive policies to private demand has assumed prominence in the Government agenda. Thus, under the justification of the fierce debate about the effectiveness of countercyclical policies of Brazil, in view of the recent economic crisis, aims to: 1) retake the theoretical debate and, to a certain extent, the evolution of the theory of household consumption, as well as some conclusions about their connection with the minimum wage; 2) to describe the experiences and the effects of this legislation in economic history, with emphasis on the Brazilian case; 3) to present some of the available statistics to research bases, with attention to the specifics of each and the empirical results found for consumption in Brazil; 4) to estimate the effects of minimum wage variation in household consumption in Brazil (BR), northeast (NE) and Rio Grande do Norte (RN). From this, in order to quantify this relationship, makes inferences from the effects of the wage bill and the minimum wage on consumption, in quarterly series (with ad hoc adjustment from the "weights" of each quarter), from classic model of multiple linear regression. The hypothesis is that released: increments in income, derived from the policy of minimum wage recovery will influence directly the household consumption. However, when comparing the results between the units analyzed, the expressiveness of the northeastern families of Brazil and Rio Grande do Norte families front national dynamics with income linked to this floor, drives most significant impacts spending decisions in NE and RN, thus reducing regional disparities in the consumer. The results indicate contrary evidence, because while for the BR a unitary variation in minimum wage increases the consumption in units monetary 1.28, to the NE and RN these parameters are respectively 1.05 and 1.09

Fatores que afetam a satisfação e a fidelidade do consumidor: um estudo com usuários de calçado esportivo (tênis), na Região Sul da cidade de Natal

This paper aims to investigate the factors that influence the satisfaction and fidelity of tennis´s users with the region southern city of Natal, capital of Rio Grande do Norte as the area of analyzing , using the national satisfaction index models as a tool to study. In this study was used the questionnaire as a tool for collecting data based on the new Norwegian customer satisfaction barometer model proposed by Johnson et. al. (2001). The data collection took place during the months of May and June 2008, when 450 tennis´s users were interviewed. The main results obtained by multiple regression analysis and logistic regression showed that the users' satisfaction with the tennis´s brand is influenced by the quality, comfort, material used in the manufacture and price, while fidelity is potentized by the image of the brand and the satisfaction degree with the user's tennis and with the brand of tennis. In relation to user satisfaction with the tennis, that satisfaction is influenced by the quality, comfort, weight and the material used, while fidelity is potentized by the satisfaction with the tennis´s brand, with the possibility of paying the same amount again and the emotional commitment. As the processing of claims there was no direct influence on satisfaction and consumers fidelity due to the low number complaints

Estágio menopausal e níveis hormonais no desenvolvimento muscular e funcional em mulheres de meia idade: um estudo transversal

Introduction: Hypoestrogenism is the main characteristic of female aging. It promotes significant changes in body composition, both in fat mass as in lean body mass, leading to a decrease in muscle strength and physical performance. Objective: The aim of this study was to test whether menopausal status and hormone levels are associated with muscular strength and physical performance in middle-aged women. Methods: In a cross-sectional study it was collected sociodemographic data, gynecological history, anthropometric and biochemical measures in women aged 40 to 65 years in Parnamirim-RN. The menopause status (pre, peri and post menopause) was determined by menstrual history. All women underwent three dimensions of physical performance assessment: handgrip dynamometry, gait speed and chair stands test - Short Physical Performance Battery (SPPB). Categorical data were presented as absolute and relative frequencies. Quantitative data were showed as mean and standard deviation and the normality of distribution was verified with Kolmogorov-Smirnov (KS) test. Biochemical measures of estradiol and follicle-stimulating hormone (FSH) were transformed to log10. ANOVA with Tukey post-test for comparison of variables between the groups pre, peri and post-menopausal was performed and then multiple linear regression analyzes. Results: Two hundred and seventy eight women aged 50.2 (±5.58) years composed this study, being 50 women in premenopausal status (18%), 122 in perimenopausal (43.9%), and 106 postmenopausal stage (38.1%). The groups were different in age (p=0.001), marital relationship duration (p <0.001), number of pregnancies (p=0.001) and parity (p=0.001). Differences in biochemical measures were observed among the groups: estradiol (p<0.001), FSH (p<0.001), total cholesterol (p=0.001). There were no differences in gait velocity between menopausal status. Values in mean of grip strength decreased by postmenopausal women to perimenopausal and premenopausal ones (24.5 ± 5.1, 25.6 ± 5.4, 26.9 ± 4.9 for post-stage, pre and peri menopausas, respectively, p = 0.02) and the performance of chair stands test was better in premenopausal women compared with that in peri and postmenopausal status (p = 0.02). In multiple linear regression for muscle strength, the variables that remained were: age, estradiol and somatic symptoms measured by Menopause Rating Scale-MRS (R2=0.15). While for the xiv chair-stands test the predictors were number of births and FSH values (R2=0.04). Conclusion: There is a relationship between the stages of menopause and muscle performance in measures of grip strength and sit-up test and these are influenced by the fall of estrogens levels. Data suggest that the decrease in muscle strength and physical performance already appear in the transition to menopause stage, pointing to the need for more research in this area and appropriate preventive interventions

A relação entre os determinantes sociais em saúde e os investimentos setoriais e a mortalidade infantil em municípios brasileiros com mais de 80 mil habitantes

Investments in health have controversial influence on results of the health of populations, besides being subject rarely explored in literature. Moreover, from the 1970s, the social determinants of health have been consolidated in the disease process as multifactorial factors (social, economic, cultural, etc.) that directly or indirectly influence the occurrence of health problems of populations, as well as mortality rates. This study aimed to evaluate the influence of these investments and the social determinants of health on infant mortality and its neonatal and post-neonatal mortality. This is an ecological study, in which the sample was composed of Brazilians cities with over 80,000 inhabitants, avoiding fluctuations in mortality rates for common small populations, and ensure greater coverage of information systems on mortality and births Brazilians and, therefore, increase data consistency. To isolate the effect of investments in health, we used multiple linear regression. The socioeconomic indicators (p <0.001, p = 0.004, p <0.001), the inequality index (p <0.001, p = 0.001, p = 0.006) and coverage of prenatal visits (p <0.001, p <0.001; p = 0.005) were associated with infant mortality rate total, neonatal and post-neonatal, and the Gross Domestic Product per capita only influenced the overall infant mortality rate and neonatal (p=0.022; 0.045). Investments in health, in this model, lost statistical significance, showing no correlation with mortality rates among children under one year. We conclude that the social determinants of health has an influence on the variation in mortality rates of Brazilian cities, however the same was not observed for indicators of health investment