Física estatística aplicada a sistemas sociais através do estudo de redes complexas

In this work a study of social networks based on analysis of family names is presented. A basic approach to the mathematical formalism of graphs is developed and then main theoretical models for complex networks are presented aiming to support the analysis of surnames networks models. These, in turn, are worked so as to be drawn leading quantities, such as aggregation coefficient, minimum average path length and connectivity distribution. Based on these quantities, it can be stated that surnames networks are an example of complex network, showing important features such as preferential attachment and small-world character

Estatística não-extensiva aplicada ao cálculo do calor específico eletrônico em estruturas quasiperiódicas

Systems whose spectra are fractals or multifractals have received a lot of attention in recent years. The complete understanding of the behavior of many physical properties of these systems is still far from being complete because of the complexity of such systems. Thus, new applications and new methods of study of their spectra have been proposed and consequently a light has been thrown on their properties, enabling a better understanding of these systems. We present in this work initially the basic and necessary theoretical framework regarding the calculation of energy spectrum of elementary excitations in some systems, especially in quasiperiodic ones. Later we show, by using the Schr¨odinger equation in tight-binding approximation, the results for the specific heat of electrons within the statistical mechanics of Boltzmann-Gibbs for one-dimensional quasiperiodic systems, growth by following the Fibonacci and Double Period rules. Structures of this type have already been exploited enough, however the use of non-extensive statistical mechanics proposed by Constantino Tsallis is well suited to systems that have a fractal profile, and therefore our main objective was to apply it to the calculation of thermodynamical quantities, by extending a little more the understanding of the properties of these systems. Accordingly, we calculate, analytical and numerically, the generalized specific heat of electrons in one-dimensional quasiperiodic systems (quasicrystals) generated by the Fibonacci and Double Period sequences. The electronic spectra were obtained by solving the Schr¨odinger equation in the tight-binding approach. Numerical results are presented for the two types of systems with different values of the parameter of nonextensivity q

Função de distribuição generalizada aplicada à velocidade de rotação estelar

In the present work we use a Tsallis maximum entropy distribution law to fit the observations of projected rotational velocity measurements of stars in the Pleiades open cluster. This new distribution funtion which generalizes the Ma.xwel1-Boltzmann one is derived from the non-extensivity of the Boltzmann-Gibbs entropy. We also present a oomparison between results from the generalized distribution and the Ma.xwellia.n law, and show that the generalized distribution fits more closely the observational data. In addition, we present a oomparison between the q values of the generalized distribution determined for the V sin i distribution of the main sequence stars (Pleiades) and ones found for the observed distribution of evolved stars (subgiants). We then observe a correlation between the q values and the star evolution stage for a certain range of stel1ar mass

Caracterização estatística de processos sísmicos via Distribuição Generalizada de Pareto. Estudo de caso: João Câmara-RN

The work is to make a brief discussion of methods to estimate the parameters of the Generalized Pareto distribution (GPD). Being addressed the following techniques: Moments (moments), Maximum Likelihood (MLE), Biased Probability Weighted Moments (PWMB), Unbiased Probability Weighted Moments (PWMU), Mean Power Density Divergence (MDPD), Median (MED), Pickands (PICKANDS), Maximum Penalized Likelihood (MPLE), Maximum Goodness-of-fit (MGF) and the Maximum Entropy (POME) technique, the focus of this manuscript. By way of illustration adjustments were made for the Generalized Pareto distribution, for a sequence of earthquakes intraplacas which occurred in the city of João Câmara in the northeastern region of Brazil, which was monitored continuously for two years (1987 and 1988). It was found that the MLE and POME were the most efficient methods, giving them basically mean squared errors. Based on the threshold of 1.5 degrees was estimated the seismic risk for the city, and estimated the level of return to earthquakes of intensity 1.5°, 2.0°, 2.5°, 3.0° and the most intense earthquake never registered in the city, which occurred in November 1986 with magnitude of about 5.2º

A teoria da ruína aplicada em um modelo de empresa financeira com risco de crédito

In this work we study a new risk model for a firm which is sensitive to its credit quality, proposed by Yang(2003): Are obtained recursive equations for finite time ruin probability and distribution of ruin time and Volterra type integral equation systems for ultimate ruin probability, severity of ruin and distribution of surplus before and after ruin

Classificador máquina de suporte vetorial com análise de Fourier aplicada em dados de EEG e EMG

The classifier support vector machine is used in several problems in various areas of knowledge. Basically the method used in this classier is to end the hyperplane that maximizes the distance between the groups, to increase the generalization of the classifier. In this work, we treated some problems of binary classification of data obtained by electroencephalography (EEG) and electromyography (EMG) using Support Vector Machine with some complementary techniques, such as: Principal Component Analysis to identify the active regions of the brain, the periodogram method which is obtained by Fourier analysis to help discriminate between groups and Simple Moving Average to eliminate some of the existing noise in the data. It was developed two functions in the software R, for the realization of training tasks and classification. Also, it was proposed two weights systems and a summarized measure to help on deciding in classification of groups. The application of these techniques, weights and the summarized measure in the classier, showed quite satisfactory results, where the best results were an average rate of 95.31% to visual stimuli data, 100% of correct classification for epilepsy data and rates of 91.22% and 96.89% to object motion data for two subjects.

Realidade aumentada aplicada em bibliotecas: multiplicidade no acesso a informação

Conceitua Realidade Aumentada do ponto de vista histórico de vários autores e como surgiu esse segmento através da evolução tecnológica até os dias atuais. Aborda seu funcionamento, como também, seus sistemas e aplicações em diversos campos de pesquisas e estudos científicos. Diferencia Realidade Aumentada de Realidade Virtual, visando melhor esclarecimento entre ambas na intenção de descaracterizá-las com uma única “realidade”. Apresenta a Realidade Aumentada e sua aplicação dentro de um contexto de uma unidade de informação, promovendo uma melhor interação com os usuários e as adaptações pelas quais as bibliotecas terão que passar futuramente para se adequarem a “explosão” tecnológica. Descreve o funcionamento da biblioteca ARToolKIT, baseada em RA e suas principais etapas de funcionamento para visualização de objetos virtuais em 3D. Exemplifica os benefícios que uma unidade de informação, que utiliza Realidade Aumentada, promove aos usuários portadores de deficiência, além de sua inclusão no meio digital e sua inserção no mercado de trabalho

Análise de volatilidade, integração de preços e previsibilidade para o mercado brasileiro de camarão

The present paper has the purpose of investigate the dynamics of the volatility structure in the shrimp prices in the Brazilian fish market. Therefore, a description of the initial aspects of the shrimp price series was made. From this information, statistics tests were made and selected univariate models to be price predictors. Then, it was verified the existence of relationship of long-term equilibrium between the Brazilian and American imported shrimp and if, confirmed the relationship, whether or not there is a causal link between these assets, considering that the two countries had presented trade relations over the years. It is presented as an exploratory research of applied nature with quantitative approach. The database was collected through direct contact with the Companhia de Entrepostos e Armazéns Gerais de São Paulo (CEAGESP) and on the official website of American import, National Marine Fisheries Service - National Oceanic and Atmospheric Administration (NMFS- NOAA). The results showed that the great variability in the active price is directly related with the gain and loss of the market agents. The price series presents a strong seasonal and biannual effect. The average structure of price of shrimp in the last 12 years was R$ 11.58 and external factors besides the production and marketing (U.S. antidumping, floods and pathologies) strongly affected the prices. Among the tested models for predicting prices of shrimp, four were selected, which through the prediction methodologies of one step forward of horizon 12, proved to be statistically more robust. It was found that there is weak evidence of long-term equilibrium between the Brazilian and American shrimp, where equivalently, was not found a causal link between them. We concluded that the dynamic pricing of commodity shrimp is strongly influenced by external productive factors and that these phenomena cause seasonal effects in the prices. There is no relationship of long-term stability between the Brazilian and American shrimp prices, but it is known that Brazil imports USA production inputs, which somehow shows some dependence productive. To the market agents, the risk of interferences of the external prices cointegrated to Brazilian is practically inexistent. Through statistical modeling is possible to minimize the risk and uncertainty embedded in the fish market, thus, the sales and marketing strategies for the Brazilian shrimp can be consolidated and widespread

Análise estatística de impedância da pele

In this work we analyze the skin bioimpedance statistical distribution. We focus on the study of two distinct samples: the statistics of impedance of several points in the skin of a single individual and the statistics over a population (many individuals) but in a single skin point. The impedance data was obtained from the literature (Pearson, 2007). Using the Shapiro-Wilk test and the assymmetry test we conclude that the impedance of a population is better described by an assymetric and non-normal distribution. On the other side, the data concerning the individual impedance seems to follow a normal distribution. We have performed a goodnes of fitting test and the better distribution to fit the data of a population is the log-normal distribution. It is interesting to note that our result for skin impedance is in simtony with body impedance from the literature of electrical engeneering. Our results have an impact over the statistical planning and modelling of skin impedance experiments. Special attention we should drive to the treatment of outliers in this kind of dataset. The results of this work are important in the general discussion of low impedance of points of acupuncture and also in the problem of skin biopotentials used in equipments like the Electrodermal Screen Tests.

Avaliação das condições higiênico-sanitárias da produção de refeições à base de carne da alimentação escolar no município de Natal-RN

The National School Nutrition Program is the oldest program in the country directed at food and nutrition safety. Its aims are to offer nutritional food as a supplement to students of public and philanthropic schools. Studying school nutrition transcends the investigation as a purely social program, given that it reaches the fields of public health, nutrition and food, using a wide variety of approaches. Thus, it is characterized by a multidisciplinary study, where the disciplines work side by side in distinct aspects of a single problem. Aim: This study aims to assess hygiene practices during the preparation of meat-based meals in public schools in the city of Natal, Brazil. Methods: A list was applied at 27 schools to identify the procedures of good food preparation practices. In addition, cooking and meal distribution temperature were measured and a microbiological analysis of the final preparation and of the water used in preparing it was performed. For microbiological analyses of the food, we analyzed coliforms at 45°C, coliforms at 35°C and Enterococcus, and for the water, we analyzed thermotolerant coliforms and total coliforms, using the methods recommended by APHA, 1995. Results: Most of the schools did not meet the required standards in all the variables related to good food preparation practices, except for the time spent preparing the meat, in which 89% were within the norm. Cooking temperature of the meals was within the standard; however, the temperature at distribution and the time spent dispensing the meals were inadequate. Of the 27 schools, 22 (81.5%) showed the presence of coliforms at 35° C in at least one meal sample and 18 (66.7%) had values above the recommended limit for coliforms at 45°C. The presence of E. coli was identified in 6.1% of the samples analyzed. The presence of Enterococcus was not found at any of the schools. With respect to the water, the North district of the city was the only one that did not meet the standards for the two indicators evaluated. The contamination found was not associated with the hygiene or food storage problems observed. Conclusions: The results show that the hygiene-sanitary conditions of meat-based public school meals were unsatisfactory, demonstrating the need for improvements in the production process to preserve the health of the student population. Multidisciplinarity: Researchers from the areas of food microbiology, nutrition, public health and statistics took part in this study, a decisive factor for characterizing the research as multidisciplinary

Polimorfismos do gene MSX1 e a fenda labio e/ou palatina não-sindrômica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Mortalidade infantil e condições socioeconômicas nas microrregiões do Nordeste Brasileiro

The study aims to answer the following question: what are the different profiles of infant mortality, according to demographic, socioeconomic, infrastructure and health care, for the micro-regions at the Northeast of Brazil? Thus, the main objective is to analyze the profiles or typologies associated mortality levels sociodemographic conditions of the micro-regions, in the year 2010. To this end, the databases of birth and death certificates of SIM and SINASC (DATASUS/MS), were taken from the 2010 population Census microdata and from SIDRA/IBGE. As a methodology, a weighted multiple linear regression model was used in the analysis in order to find the most significant variables in the explanation child mortality for the year 2010. Also a cluster analysis was performed, seeking evidence, initially, of homogeneous groups of micro-regions, from of the significant variables. The logit of the infant mortality rate was used as dependent variable, while variables such as demographic, socioeconomic, infrastructure and health care in the micro-regions were taken as the independent variables of the model. The Bayesian estimation technique was applied to the database of births and deaths, due to the inconvenient fact of underreporting and random fluctuations of small quantities in small areas. The techniques of Spatial Statistics were used to determine the spatial behavior of the distribution of rates from thematic maps. In conclusion, we used the method GoM (Grade of Membership), to find typologies of mortality, associated with the selected variables by micro-regions, in order to respond the main question of the study. The results points out to the formation of three profiles: Profile 1, high infant mortality and unfavorable social conditions; Profile 2, low infant mortality, with a median social conditions of life; and Profile 3, median and high infant mortality social conditions. With this classification, it was found that, out of 188 micro-regions, 20 (10%) fits the extreme profile 1, 59 (31.4%) was characterized in the extreme profile 2, 34 (18.1%) was characterized in the extreme profile 3 and only 9 (4.8%) was classified as amorphous profile. The other micro-regions framed up in the profiles mixed. Such profiles suggest the need for different interventions in terms of public policies aimed to reducing child mortality in the region

A revenda de combustível e os limites constitucionais para a sua regulação: uma análise aplicada aos aspectos concorrênciais e ao controle de preços

The gas retail represents the end of a section of the oil and natural gas derivative chain, for it is at this stage where the commercialization of those merchandises takes place towards the costumers. This process involves an enormous amount of economic agents, which reflects on an activity of great influence on the citizen's everyday. By the time of the gas retail price liberalization, in 2002, there were great expectations towards that measure, for the insertion of that segment in a competitive market was likely to create a decrease in prices. As there was not a drastic drop off in cost, the question was no longer the price itself, but, predominantly, the conduct taken by the economic agents that operate the market. Not in vain, the segment introduces a greater number of different procedures combined with the organs that compose the Brazilian System of Competition Protection. What is understood, however, is that many of these complaints are made in a lightly way, without a proper analysis of the market and its practices, that being why, in this paper, evidences the causes of these complaints and explained what, in fact, occurs in this market. Also, the organs that protect the free initiative in the sector use different methods to assess anticompetitive practices, which are counterproductive on the combat of anticompetitive practice, that being why the present paper analyzes the used methods on a critic perspective, choosing one which is believed to be the most adequate. The present work also tries to present the gas retail prices on a constitutional, free competition, free initiative and consumers defense perspective, analyzing the competition s aspects on the gas market; the shaping of the gas prices; the market boundaries; the anti-competitive practices under the gas market; and analyze the possibility, according to the defined economic standards in the constitutional text of existing a greater control or gas price indexing and/or regulation which limits the distributors and resellers profit on gas. Still, in consequence of this analysis, a study on Natal s market behavior will be developed in its competitive feature. That being said, moreover being a theoretical-descriptive study, data and statistics gathered is used, which will lead, willing to grasp an experiential study on a few aspects of the Potiguar gas retail market

Turismo de eventos como estratégia no combate à sazonalidade: uma análise na hotelaria de Natal - RN

The aim of this work is to analyse the tourism events and the performance of this segment from market as strategy in the combat of Natal's hotel seasonality, in the executives/managers's vision from this sector. Two searches were realized to turn available this study: Inicialy a bibliographic search involving the concepts associated with the tematic in question so that it arranges the embasament theoric-scientific and a survey from facts through the country search, where it was applicable in the establishments of work's population with the auxiliary from a formulary answered by a personal interview. The analyses techniques through facts were: estatistic descritive and Kolmogorov-smirnov test.Among the results found, it was verified that the main reasons alleged by the hotels to ingress in the segment from the events were the alinement from the competitive company, the diversification in the options in the sense of occupy the establishments during the period of low season and answer to the demand of market. Investigated the profile from the events occured in the Natal hotels referring to the port, public origin , kinds of events and frequency from their realizations, as well as , the capacity from these establishments to attend this segment.It was noticed that in spite of the hotels agree that the events are important estrategies to combat the seasonality, the establishments still suffer with the flutuation, what can be justified from the moment that it's considered that the events also behave from seasonal manner, having more concentration in certain periods from the year. It was evaluated that the main advantage noticed by the realization from the hotels's events is the utilization from alimentation and drinking services, surpassing the advantage from elevation of taxes occupation from the apartments

Qualidade em obras públicas: um estudo comparativo entre as metodologias Seis Sigma, ISO 9000 e PBQP-H no RN

In Brazil the theme quality in public construction has been widely discussed in the early 1990s, with the creation of the Brazilian Program of Quality and Productivity for the Habitat (PBQP-H) which is strongly influenced by the wave of studies on issues of quality in the world, such as the ISO 9000. Over the years, other approaches have emerged and been consolidated, evolving from market and customer´s needs. An example is the Six Sigma methodology. This study aims to examine the Six Sigma, ISO 9000 and PBQP-H methodologies, noting the common elements, differences, gaps and how the methods are complementary, so that with the ongoing work, proposed initiatives can be developed to improve the quality that enables its application in public construction. Still aiming to optimize the deployment of the proposed initiatives, it was performed an analysis of ISO 9001 and PBPQ-H certifications in Brazil and in the state of Rio Grande do Norte, with respect to the construction industry and a case study to identify the factors that influence the adoption of initiatives to improve quality, and check if the selected construction company is prepared to implement the proposed initiatives. This research is characterized as exploratory and applied, with literature review and a case study. The data collection instrument was a questionnaire and the statistical analysis used a multidimensional scaling method. The conclusion is that the methodologies are compatible and complementary, and their integration could potentialize the goals set. It was identified that the state of Rio Grande do Norte has a few number of certifications in construction. Nine initiatives are proposed for implementation at construction companies. In the case study it was found that the studied company would be able to implement the suggestions proposed and the requirement for certification by clients and funding institutions influence the adoption of quality improvement initiatives. This result confirms the literature which states that top management support is crucial for the successful implementation of quality methodologies