82 resultados para Regressão linear local
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
This study analyzed the Worker’s Healthy Eating Program in Rio Grande do Norte state (RN) to assess its possible impact on the nutritional status of the workers benefitted. To that end, we conducted a cross-sectional observational prospective study based on a multistage stratified random sample comparing 26 small and medium-sized companies from the Manufacturing Sector (textiles, food and beverages, and nonmetallic minerals) of RN, divided into two equal groups (WFP and Non WFP). Interviews were conducted at each company by trained interviewers from Tuesday to Saturday between September and December 2014. Data were collected on the company (characterization and information regarding the program’s desired results) and workers (personal and professional information, anthropometrics, health, lifestyle and food consumed the previous day). Population estimates were calculated for RN on the characteristics of workers and the study variables. The main variable was BMI. The secondary variables were waist circumference (WC), nutritional diagnosis, calorie intake, blood pressure, metabolic variables and lifestyle indicators. The statistical method used was hierarchical mixed effects linear regression for interval variables and hierarchical mixed effects logistic regression for binary variables. The variables measured in ordinal scales were analyzed by ordinal logistic regression adjusted for correlated variables, adopting robust standard errors. The results for interval variables are presented as point estimates and their 95% confidence intervals; and as odds-ratios and their 95% confidence intervals for binary variables. The Fisher’s exact and Student’s t-tests were used for simple comparisons between proportions and means, respectively. Differences were considered statistically significant at p<0.05. A total of 1069 workers were interviewed, of which 541 were from the WFP group and 528 from the Non WFP group. Subjects were predominantly males and average age was 34.5 years. Significant intergroup differences were observed for schooling level, income above 1 MW (minimum wage) and specific training for their position at the company. The results indicated a significant difference between the BMI of workers benefitted, which was on average 0.989 kg/m2 higher than the BMI of workers from the Non WFP group (p=0.002); and between the WC, with the waist circumference of WFP group workers an average of 1.528 cm larger (p<0.05). Higher prevalence of overweight and obesity (p<0.001) and cardiovascular risk (p=0.038) were recorded in the WFP group. Tests on the possible effect of the WFP on health (blood pressure and metabolic indicators) and lifestyle indicators (smoking, alcohol consumption and exercise) were not significant. With respect to worker’s diets, differences were significant for consumption of saturated fat (lunch and daily intake), salt (lunch, other meals and daily intake) and proteins (other meals and daily intake), with higher consumption of these nutrients in the WFP group. The study showed a possible positive impact of the WFP on nutritional status (BMI and WC) among the workers benefitted. No possible effects of the program were observed for the lifestyle indicators studied. Workers benefitted consumed less salt, saturated fat and protein. The relevance of the WFP is recognized for this portion of society and it is understood that, if the program can reach and impact those involved, the development of educational initiatives aimed at nutritional and food safety may also exert a positive influence.
Resumo:
The present report is the result of an applied research in the educational entities of the third sector, aiming to demonstrate whether the financial influences the perception of users on the image of those entities. For both used the prospect of integrative marketing relationship adapting to and developing a set of indicators which bore the measurement of images from the model of Machado et al (2005) and Kotler and Fox (1994). The sample included a total of 187 parents and financial responsibility in 03 (three) institutions of education in Natal / RN. These data were processed by multivariate statistical analysis, factor analysis, linear regression, analysis of cluster and discriminant analysis. The factor analysis also identified 6 images perceived by users of services. Next were the relationships of cause and effect between the financial and images formed. In discriminant analysis, was identified two distinct groups of parents and guardians with financial perceptions similar and well defined. The result of the work shows that the differential level of financial participation of parents and guardians not influence the formation of the images formed from educational institutions of the third sector
Resumo:
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
Resumo:
This study examines the complex hotel buyer decision process in front of the tourism distribution channels. Its objective is to describe the influence level of the tourism marketing intermediaries, mainly the travel agents and tour operators, over the hotel decision process by the buyer-tourist. The data collection process was done trough a survey with three hundred brazilian tourists hosted in nineteen hotels of Natal, capital of Rio Grande do Norte, Brazil. The data analysis was done using some multivariate statistic techniques as correlation analysis, multiple regression analysis, factor analysis and multiple discriminant analysis. The research characterizes the hotel services consumers profile and his trip, and identifying the distribution channels used by them. Furthermore, the research verifies the intermediaries influence exercised over hotel buyer decision process, looking for identify causality relations between the influence level and the buyer profile. Verifies that information about hotels available on internet reduces the probability that this influence can be practiced; however it was possible identifying those consumers considers this information complementary and non-substitutes than the information from intermediaries. The characteristics of the data do not allow indentifying the factors that constraint the intermediaries influence neither identifying discriminant functions of the specific distribution channel choice by consumers. The study concludes that consumers don t agree in have been influenced by intermediaries or don t know if they have, still considering important to consult them and internet doesn t substitute their function as information source
Resumo:
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
Resumo:
This research aims to understand the factors that influence intention to online purchase of consumers, and to identify between these factors those that influence the users and the nonusers of electronic commerce. Thus, it is an applied, exploratory and descriptive research, developed in a quantitative model. Data collection was done through a questionnaire administered to a sample of 194 graduate students from the Centre for Applied Social Sciences of UFRN and data analysis was performed using descriptive statistics, confirmatory factorial analysis and simple and multiple linear regression analysis. The results of descriptive statistics revealed that respondents in general and users of electronic commerce have positive perceptions of ease of use, usefulness and social influence about buying online, and intend to make purchases on Internet over the next six months. As for the non-users of electronic commerce, they do not trust the Internet to transact business, have negative perceptions of risk and social influence over purchasing online, and does not intend to make purchases on Internet over the next six months. Through confirmatory factorial analysis six factors were set up: behavioral intention, perceived ease of use, perceived usefulness, perceived risk, trust and social influence. Through multiple regression analysis, was observed that all these factors influence online purchase intentions of respondents in general, that only the social influence does not influence the intention to continue buying on the Internet from users of electronic commerce, and that only trust and social influence affect the intention to purchase online from non-users of electronic commerce. Through simple regression analysis, was found that trust influences perceptions of ease of use, usefulness and risk of respondents in general and users of electronic commerce, and that trust does not influence the perceptions of risk of non-users of electronic commerce. Finally, it was also found that the perceived ease of use influences perceived usefulness of the three groups. Given this scenario, it was concluded that it is extremely important that organizations that work with online sales know the factors that influence consumers purchasing intentions in order to gain space in their market
Resumo:
In an environment of constant change, technological developments, market competition and more informed consumers, the search for a lasting relationship through the conquest of loyalty has become the objective of companies. However, several authors suggest that this loyalty can be affected by negative comments available on the internet. Therefore, this dissertation has as objective to examine if the complaints are available on the internet impact the loyalty to a brand of mobile phone. The research used as the basis the Expanded NCSB model suggest by Johnson et al. (2001), studying five prominent drives of loyalty: image/brand reputation, affective commitment, calculative commitment, perceived value and trust, beyond the satisfaction construct as moderator variable. The research method adopted was the experimental design which included 285 undergraduate students, with the trial which included 285 undergraduate students, with the field study of the mobile industry, specifically, the brands of cell phones. The research approach was quantitative and methods were descriptive statistics, factor analysis, cluster analysis, linear regression and non-parametric test of Wilcoxon for data analysis. Of the 16 hypothesis stemmed from the research model proposed, 12 were confirmed. The results showed that the complaint available on the internet, here represented by the available on the site Reclame Aqui, may impact consumer perceptions about brand loyalty, as well as its antecedents, being that these complaints can affect all the consumers, regardless of historical satisfaction with the brand. It also noted the positive relationship between the independent variables trust, image/brand reputation, perceived value, affective commitment and calculative commitment and the dependent variable - loyalty, even when considering the data obtained after exposure to the complaint. However, no unanimous conclusion that the relationship between these variables was strongest in the group with satisfactory experience. At the first moment of the research, the trust was the most important variable for the formation of loyalty. However, after exposure to treatment, the image/brand reputation, was more relevant. Contributions of the study, limitations and recommendations for future researches are approached in the present investigation
Resumo:
The research in question looked for to establish the relation between the motivation (of the proprietor of apartment) to change itself of another one apartment, in closed vertical condominium (residential mobility) in the period of the recognition of the necessity, and the satisfaction with the apartment after consume. The universe or the population chosen for the development of the study was of proprietors of apartment in vertical condominiums located in the region metropolitan of Natal. The analysis of data was made using the techniques of linear regression and logistic regression between variables. The linear regression found relations between the motivations for housing change and the satisfaction in after consume with some attributes of the apartment. The logistic regression showed that relations between the motivations for change and the general satisfaction to the apartment exist as a whole, in the period after consumes. With regard to the motivation to change itself of a apartment for another one, some reasons shown more motivation them the others. The research found different degrees of satisfaction with certain characteristics of the apartment and degrees of no satisfaction with others. Finally the results of the research had contributed for the reply of the problem that guided the present study, therefore had obtained in such a way to find how much logistic not linear relations between the two periods purchase (recognition of the necessity and evaluation after consume) and had elucidated the process that goes since the choice the product until the satisfaction of the necessities
Resumo:
The objective is to analyze the relationship between risk and number of stocks of a portfolio for an individual investor when stocks are chosen by "naive strategy". For this, we carried out an experiment in which individuals select actions to reproduce this relationship. 126 participants were informed that the risk of first choice would be an asset average of all standard deviations of the portfolios consist of a single asset, and the same procedure should be used for portfolios composed of two, three and so on, up to 30 actions . They selected the assets they want in their portfolios without the support of a financial analysis. For comparison we also tested a hypothetical simulation of 126 investors who selected shares the same universe, through a random number generator. Thus, each real participant is compensated for random hypothetical investor facing the same opportunity. Patterns were observed in the portfolios of individual participants, characterizing the curves for the components of the samples. Because these groupings are somewhat arbitrary, it was used a more objective measure of behavior: a simple linear regression for each participant, in order to predict the variance of the portfolio depending on the number of assets. In addition, we conducted a pooled regression on all observations by analyzing cross-section. The result of pattern occurs on average but not for most individuals, many of which effectively "de-diversify" when adding seemingly random bonds. Furthermore, the results are slightly worse using a random number generator. This finding challenges the belief that only a small number of titles is necessary for diversification and shows that there is only applicable to a large sample. The implications are important since many individual investors holding few stocks in their portfolios
Resumo:
This research aims to investigate the Hedge Efficiency and Optimal Hedge Ratio for the future market of cattle, coffee, ethanol, corn and soybean. This paper uses the Optimal Hedge Ratio and Hedge Effectiveness through multivariate GARCH models with error correction, attempting to the possible phenomenon of Optimal Hedge Ratio differential during the crop and intercrop period. The Optimal Hedge Ratio must be bigger in the intercrop period due to the uncertainty related to a possible supply shock (LAZZARINI, 2010). Among the future contracts studied in this research, the coffee, ethanol and soybean contracts were not object of this phenomenon investigation, yet. Furthermore, the corn and ethanol contracts were not object of researches which deal with Dynamic Hedging Strategy. This paper distinguishes itself for including the GARCH model with error correction, which it was never considered when the possible Optimal Hedge Ratio differential during the crop and intercrop period were investigated. The commodities quotation were used as future price in the market future of BM&FBOVESPA and as spot market, the CEPEA index, in the period from May 2010 to June 2013 to cattle, coffee, ethanol and corn, and to August 2012 to soybean, with daily frequency. Similar results were achieved for all the commodities. There is a long term relationship among the spot market and future market, bicausality and the spot market and future market of cattle, coffee, ethanol and corn, and unicausality of the future price of soybean on spot price. The Optimal Hedge Ratio was estimated from three different strategies: linear regression by MQO, BEKK-GARCH diagonal model, and BEKK-GARCH diagonal with intercrop dummy. The MQO regression model, pointed out the Hedge inefficiency, taking into consideration that the Optimal Hedge presented was too low. The second model represents the strategy of dynamic hedge, which collected time variations in the Optimal Hedge. The last Hedge strategy did not detect Optimal Hedge Ratio differential between the crop and intercrop period, therefore, unlikely what they expected, the investor do not need increase his/her investment in the future market during the intercrop
Resumo:
This work aims to obtain a low-cost virtual sensor to estimate the quality of LPG. For the acquisition of data from a distillation tower, software HYSYS ® was used to simulate chemical processes. These data will be used for training and validation of an Artificial Neural Network (ANN). This network will aim to estimate from available simulated variables such as temperature, pressure and discharge flow of a distillation tower, the mole fraction of pentane present in LPG. Thus, allowing a better control of product quality
Resumo:
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)
Resumo:
Universidade Estadual do Rio Grande do Norte
Resumo:
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
Resumo:
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