Stable fixation of implants such as artificial teeth depends on the direct apposition of bone to the implanted material. While endosseous implants were traditionally allowed to "osseointegrate" over several months without carrying load, clinical and experimental data show that prostheses with roughened surfaces allow successful integration when subject to earlier loading and more challenging implant sites. However, to design implant surfaces for an optimal biological response requires an understanding of the mechanism by which roughened surfaces promote osseointegration. Research into this mechanism has, to date, focussed primarily on the response of osteoblastic cells to surface topography in vitro. While these have demonstrated some consistent trends in cell behaviour, the fundamental means by which cells sense and respond to roughness remain unclear. It has been suggested that cell responses to changes in topography may relate to differences in the proteins adsorbed from serum (in vitro). While experimental evidence indirectly suggests that physical features can affect protein adsorption, few studies have examined this with respect to surface roughness, particularly as a mediator of cell responses. To address this issue, cell culture and protein adsorption experiments were conducted on a limited range of surface textures. Titanium samples were ground to produce morphologically similar surfaces with three grades of roughness. A duplicate set of specimens were heated at 600°C for one hour, with the aim of masking potential variations in physicochemical properties with differing degrees of grinding. Osteoblast attachment and proliferation studies were conducted over a short time-frame of 48 hours or less, to highlight the effects of proteins adsorbed from serum rather than secreted by adherent cells. Gel electrophoresis provided a profile of the proteins adsorbed to each surface after 15 minutes, corresponding to the time by which the cells had settled onto the surface. Finally, confocal microscopy was used to examine cell morphology on each surface, and to visualize specific interactions between cellular structures and adsorbed adhesion-mediating proteins. Although the effects were inconsistent, attachment assays showed some indications that fewer cells attached in the first 90 minutes as roughness increased. This inverse cell number-roughness trend was significant at 48 hours; however, the variability in attachment assays prevented reliable separation of attachment and proliferation rate effects. While the reduction in cell number with increasing roughness is consistent with previous reports, it is typically observed at later time points, and thus may be increasingly confounded by contact inhibition and differentiation. Thermal oxidation of the titanium did not impact on osteoblast responses to roughness, although it significantly slowed cell proliferation. The latter result was unexpected on the basis of previous reports. One-dimensional gel electrophoresis revealed no significant differences in the composition of adsorbed layers with variations in roughness. However, as expected on account of wettability changes, the heat-treatment did correspond to significant changes in the adsorption profile. While this was not a highly sensitive analysis, it suggests that the cell responses to roughness changes were not governed by broadscale differences in the proteins initially available to adhering cells. In addition to the composition of the adsorbed layer, the distribution of proteins may also vary with topography. The immunofluorescence methods were not sufficiently sensitive to reveal the distribution of adsorbed adhesion proteins (vitronectin and fibronectin). However, the lack of clear labelling does suggest an absence of large accumulations due to specific topographic features. Further work is required to address this issue conclusively. Observations of cell morphology were consistent with widely-reported contact guidance phenomena on grooved surfaces, with elongation and alignment (with topography) increasing with groove depth. Cell elongation was also enhanced on the more hydrophilic, heat-treated titanium, but this effect diminished over time. Although increased elongation at 90 minutes corresponded to lower cell numbers at 48 hours, no causal relationship has yet been established.

Foodborne diseases form a large group of infectious diseases. These substantial diseases are occurring more in developing countries but they do not avoid developed countries. The originators of the disease are bacteria and their toxins, viruses, parasites and prions, whose source is an infected person or animal. The disease is passed on by contaminated soil, contaminated water and food, sometimes contaminated items. Greatest importance in the prevention of foodborne disease are nonspecific measures, protection of drinking water, safe food production, waste disposal, functional sewer system, rodenticides and insecticides measures and of course the principles of personal hygiene, certain standards of hygiene and health education of the population. Intestinal infections are preventable. The consumer can effectively protect by following the fundamental principles established by the World Health Organization. The aim of this study was to explore knowledge of foodborne disease prevention measures and compliance with these principles by adolescents in the Milevsko region. The theoretical part of the study summarizes the basic information about intestinal diseases and describes their effect on health from a variety of perspectives. The preventive measures which everyone should be aware of and apply them in everyday life to protect health are described in great detail. The paper summarizes the information about the process of spreading foodborne diseases and epidemiological measures focused on supply, routes of transmission and susceptible individuals. The theoretical part includes basic information about specific intestinal infections which are most significant for the population in the Czech Republic. Briefly described are treatment of these diseases and the most important legislative measures. In the research part quantitative research was applied by questionnaire. The research groups were students of higher secondary vocational schools and vocational schools in the region Milevsko. Three hypotheses were formulated. Statistical hypothesis testing was performed using the t test. The values of the achieved significance level are compared with a predetermined level of significance. The first hypothesis assumed that knowledge about prevention of intestinal diseases is higher among girls than boys. This statement has not been confirmed. Knowledge of the principles of prevention does not differ according to the criteria of gender. Two further hypotheses assumed that the observance of hygienic measures in the prevention of foodborne disease is higher among girls than among boys and higher for high-school graduates than apprentices. These hypotheses are valid. Precautionary principles are indeed respected more by girls than boys and high-school graduates than apprentices. The carried out research shows that adolescents in the region Milevsko have a good knowledge of foodborne infections and do known also essential preventive measures. However, knowledge of these rules does not mean they are applied in practice. The results showed that some rules, such as washing fruits and vegetables before eating, adequate boiling or roasting of food, especially hand hygiene before eating food or after contact with an animal are observed by a smaller percentage of respondents than that reported knowledge of these principles. A positive finding is that respondents comply with certain rules, without being aware of them, such as the principle of proper preservation of precooked food. Foodborne diseases are diseases which can be prevented in compliance with precautionary principles. Especially in the Czech Republic, where nonspecific principles are at a high level. It is up to each user/consumer how consistent these principles will be. Respecting preventive measures is a prerequisite for reducing the incidence of foodborne disease in the population.

Made available in DSpace on 2016-06-02T20:00:24Z (GMT). No. of bitstreams: 1 2462.pdf: 3457957 bytes, checksum: 8b5897da5658a003e8d102db1a2b6620 (MD5) Previous issue date: 2007-03-29 / Financiadora de Estudos e Projetos / Urban occupation in rural areas by settlements without approval is a growing phenomenon in São Paulo State medium-sized cities, and so far, few works have been carried out about these illegal settlements out of large cities. Such theme-based studies are relevant due to the resulting occurrence of high magnitude negative impacts. The present paper deals with the expansion process of illegal settlements both irregular and unauthorized ones , having as a study case the city of São José do Rio Preto. The aim is to study the phenomenon of illegal settlements production in this city, through their identification and qualification, also the search of causal relationship of this production, analyzing the legal situation and the relationship between this production and public policies and the real estate market dynamics and finally identifying and evaluating the resulting socialenvironmental impacts. / A ocupação urbana em zona rural por parcelamentos sem aprovação é um fenômeno crescente em cidades de porte médio do estado de São Paulo e, até o momento, são poucos os trabalhos realizados sobre esses loteamentos ilegais fora das grandes cidades. É de grande relevância a realização de estudos sobre o tema devido à conseqüente ocorrência de impactos negativos de alta magnitude. A presente pesquisa trata do processo de expansão dos loteamentos ilegais tanto os irregulares, quanto os clandestinos , tomando como estudo de caso o município de São José do Rio Preto. Seu principal objetivo é estudar o fenômeno da produção de parcelamentos ilegais neste município através da identificação e qualificação dos parcelamentos ilegais existentes, da busca da relação causal da produção dos mesmos, analisando a situação legal e a relação dessa produção com as políticas públicas e a dinâmica do mercado imobiliário e, por fim, identificar e avaliar os impactos sócio-ambientais resultantes.

Made available in DSpace on 2014-12-17T15:01:13Z (GMT). No. of bitstreams: 1 PaulaKLS.pdf: 655947 bytes, checksum: 42dfa97fce97ed099a5660c9d396a0eb (MD5) Previous issue date: 2008-02-29 / In the petroleum industry, water is always present in the reservoir formation together with petroleum and natural gas and this fact provokes the production of water with petroleum, resulting in a great environmental impact. Several methods can be applied for treatment of oily waters, such as: gravitational vases, granulated media filtration systems, flotation process, centrifugation process and the use of hydrocyclones, which can also be used in a combined way. However, the flotation process has showed a great efficiency as compared with other methods, because these methods do not remove great part of the emulsified oil. In this work was investigated the use of surfactants derived from vegetable oils, OSS and OGS, as collectors, using the flotation process in a glass column with a porous plate filter in its base for the input of the gaseous steam. For this purpose, oil/water emulsions were prepared using mechanical stirring, with concentrations around 300 ppm. The air flow rate was set at 700 cm3/min and the porous plate filter used for the generation of the air bubbles has pore size varying from 16 to 40 Pm. The column operated at constant volume (1500mL). A new methodology has been developed to collect the samples, where, instead of collecting the water phase, it was collected the oil phase removed by the process in the top of the flotation column. It has been observed that it is necessary to find an optimum surfactant concentration to achieve enhanced removal efficiency. Being for OSS 1.275 mmol/L and for OGS 0.840 mmol/L, with removal efficiencies of 93% and 99%, respectively, using synthetic solutions. For the produced water, the removal in these concentrations was 75% for OSS and 65% for OGS. It is possible to remove oil from water in a flotation process using surfactants of high HLB, fact that is against the own definition of HLB (Hydrophile-Lipophile Balance). The interfacial tension is an important factor in the oil removal process using a flotation process, because it has direct interference in the coalescence of the oil drops. The spreading of the oil of the air bubble should be considered in the process, and for the optimum surfactant concentrations it reached a maximum value. The removal kinetics for the flotation process using surfactants in the optimum concentration has been adjusted according to a first order model, for synthetic water as for the produced water. / Na ind?stria petrol?fera, a ?gua est? associada ao petr?leo e ao g?s natural, formando a ?gua de produ??o e gerando um grande impacto ambiental. Existem diversos m?todos de tratamento para as ?guas oleosas, tais como: vasos gravitacionais, sistemas de filtra??o em meio granular, flota??o, centrifuga??o e utiliza??o de hidrociclones, podendo ser utilizados de forma combinada. Entretanto, a flota??o tem mostrado maior efici?ncia com rela??o aos outros m?todos, pois eles n?o conseguem remover grande parte do ?leo emulsionado. O presente trabalho estuda a utiliza??o de tensoativos de origem vegetal, OSS (?leo de Soja Saponificado) e OGS (?leo de Girassol Saponificado), como coletores, atrav?s da flota??o em uma coluna com aera??o da suspens?o atrav?s de uma placa porosa. Para este fim, foram preparadas emuls?es ?leo/?gua por agita??o mec?nica, com concentra??es m?dias de 300 ppm. A vaz?o de ar utilizada foi de 700 cm3/min e o filtro de placa porosa utilizado para a gera??o das bolhas de ar foi de porosidade de (16-40) Pm. A coluna trabalhou a um volume constante de 1500mL. Desenvolveu-se uma nova metodologia para coletar as amostras, onde, ao inv?s de coletar a ?gua, coletou-se o ?leo removido na parte superior da c?lula de flota??o. Observou-se que ? necess?rio encontrar uma concentra??o ?tima de tensoativo para que haja uma maior efici?ncia de remo??o. S?o elas 1,275 mmol/L para o OSS e 0,840 mmol/L para o OGS, com efici?ncias de remo??o de 93 % e 99 %, respectivamente, em ?guas sint?ticas. Para a ?gua de produ??o, a remo??o nestas concentra??es foi de 75% para o OSS e 65% para o OGS. ? poss?vel remover ?leo de ?gua em um processo de flota??o utilizando tensoativos de BHL alto, fato que contraria a pr?pria defini??o de BHL (Balan?o Hidrof?lico-Lipof?lico). A tens?o interfacial ? um fator importante no processo de remo??o do ?leo na flota??o, pois interfere diretamente na coalesc?ncia das gotas de ?leo. O espalhamento do ?leo da bolha de ar deve ser considerado no processo, e para as concentra??es ?timas de tensoativo atingiu um valor m?ximo. A cin?tica da remo??o se ajustou para o modelo de primeira ordem na flota??o utilizando tensoativos na concentra??o ?tima, tanto para ?gua sint?tica como para a ?gua de produ??o.

Le relief représente une perturbation de l’épandage, qui n’est pas encore gérée par les épandeurs centrifuges des engrais minéraux. Pour combler cette lacune, nous proposons de développer un nouveau dispositif de commande. Un modèle est d’abord développé afin d’avoir des cartes d’application mettant en exergue les erreurs d’application dans divers cas du relief. Il utilise une technique de mise à jour des conditions initiales des vols balistiques en tenant compte des angles d’inclinaison du tracteur à chaque point de la trajectoire. Les simulations effectuées montrent que les amplitudes de surdosage et de sous-dosage peuvent atteindre ±40%, et sont dues à la modification de la portée des particules comparée à la situation sur un terrain plat. Les reliefs irréguliers sont les plus affectés à cause de la différence d’inclinaison entre le tracteur et la surface d’épandage, tandis que seule la gravité agit dans le cas de reliefs réguliers. En tenant compte de ces résultats, un système qui commande l’inclinaison des disques est proposé car il est capable de corriger les écarts de portée des particules tout en ciblant les zones fortement affectées. Les lois de commande sont déduites de la résolution d’un problème d’optimisation. L’objectif y est de minimiser la somme des écarts quadratiques de portée d’un nombre limité de particules représentatives de la déformation de la nappe statique. Cette approche de correction permet de réduire les erreurs d’application à l’intervalle admissible de ±10%, même en présence de changements d’attitude de haute fréquence du tracteur. / Non-flat fields represent a disturbance for fertilizer spreading, that is not handled yet by centrifugal spreaders. To bridge this gap, a new control device is proposed. A model is build first to derive application rate maps highlighting application errors in several cases. It uses an updating technique of ballistic flights initial conditions, taking into account the tractor orientation. The simulations conducted show that overapplication and underapplication may reach ±40%, and that they stem from altered particles range compared to that on a flat field. Irregular fields are the most affected due to the difference between the tractor and spread surface inclination, while only the gravity acts on regular fields. These results allowed retaining a system based on discs inclination, because it can both correct the particles range and target the most affected areas. The control laws are deduced from solving an optimization problem. Its objective is minimizing the sum of quadratic range errors of a limited number of particles representative of the static the spread pattern deformation. This approach allows reducing the application errors to ±10%.

The first step on the way to understanding the complicated dynamics of spray is to study the behavior of isolated droplets. In many industrial and natural processes such as turbulent combustion, agricultural sprays, spray cooler, falling raindrops and cloud evolution the droplet is subjected to a chaotic unsteady external flow field. The interaction between the liquid and gaseous phases results in very intricate droplet dynamics like capillary instabilities, atomization, droplet collision and coalescence and vaporization, to name a few. In this dissertation, the focus is on shape oscillations, atomization and vaporization dynamics of pendant and sessile droplets. A droplet residing on a substrate which vibrates vertically at ultrasonic frequency will exhibit different modes of shape oscillation. The competition between capillary forces and inertia forces is basically responsible for these oscillations. However, when an acoustic force field is introduced asymmetrically around the droplet, we discover with the help of ultra high-speed imaging, a new droplet spreading phase. This new method of droplet manipulation could nd application in micro fluidics and lab-on-a-chip systems. By lading the droplet with nanoparticles, the spreading rate can be easily controlled. The spreading phase is followed by an atomization phase where surface ligaments grow to disintegrate into daughter droplets; the intensity of atomization is found to decrease with increase in fluid viscosity. The ability to control atomization characteristics of droplets by lading them with nanoparticles is a powerful technique that may be implemented in spray coolers and combustors to control the spray characteristics or combustion efficiency. Both the spreading and ligament dynamics have been theoretically simulated and the physics behind the observed trends is explained. The growth rate of the ligaments is found to be governed by Weber number modified to include the acoustic pressure level of the standing wave. The frequency of ligament breakup is found to decrease with fluid viscosity and this observation is adequately supported by a theory developed based on the evolution crater on the droplet surface. Turning now to the pendant droplets, by decomposing the droplet shape into Legendre modes, the shape oscillations exhibited by a droplet hanging from the junction of cross-wire placed at the center of an air jet is studied. Both high-speed imaging and hot-wire anemometry are employed. The driving force of oscillation of droplets subjected to the air jet is proved to be the inherent pressure fluctuations in the jet. The effect of surface tension, viscosity and Reynolds number on the shape oscillation level has been examined. The first experimental evidence of viscous attenuation of lower frequencies in a particular mode in glycerol/water mixture is reported. A theoretical model was developed to simulate the droplet shape oscillations induced by different ambient flow fields like pulsatile flow, vortical flow and flow with broadband energy spectrum. The time of interaction of the droplet with an eddy in the flow is found to be very crucial in determining the amplitude of oscillation of the droplet. The shorter the interaction time, the higher are the chances of the droplet oscillation being pushed into resonance. Finally, the heat transfer and droplet regression dynamics of pendant droplets in a hot air stream of various chemical compositions (like conventional fuels, alternative fuels and nanosuspensions) have been experimentally analyzed using high speed imaging. The droplet is deployed at the junction of cross-wire at the centre of a vertical air jet. A hybrid timescale has been proposed which incorporates the effects of latent heat of vaporization, saturation vapor pressure and thermal diffusivity. This timescale in essence encapsulates the different parameters that influence the droplet vaporization rate. The analysis further permitted the evaluation of the effect of various parameters such as surrounding temperature, Reynolds number, far-field vapor presence, impurity content and agglomeration dynamics (nanosuspensions) in the droplet.

Investigações da dinâmica crítica em modelos de magnetismo, para tempos curtos, têm aparecido com grande freqüência na literatura. Essa técnica foi descoberta por Li, Schülke e Zheng que, inspirados em trabalhos anteriores de Huse e Janssen et al., mostraram que generalizações de grandezas como a magnetização e o cumulante de Binder exibem comportamento universal já no início da simulação. O estudo da criticalidade em tempos curtos proporciona um caminho alternativo para a estimativa do expoente z, além de permitir o cálculo de um novo expoente dinâmico θ, associado ao comportamento anômalo da magnetização. Da mesma forma, simulações dependentes do tempo tornaram-se ferramenta útil para estudar transições de fase em autômatos celulares e modelos de spin. Em particular, as melhores estimativas para o expoente z do Ising bidimensional foram obtidas por meio da técnica de propagação de danos, introduzida por Kauffman no estudo de autômatos e mais tarde generalizada para modelos de spin. Na primeira parte deste trabalho utilizamos o método Monte Carlo em tempos curtos para investigar o modelo de Baxter-Wu, definido em uma rede bidimensional triangular com variáveis do tipo Ising, acopladas por interações de três corpos. Obtivemos os expoentes críticos dinâmicos z e θ além dos índices críticos estáticos ß e Nû. Os resultados não corroboram aqueles recentemente obtidos por Santos e Figueiredo para o expoente z. Na segunda parte do trabalho, investigamos a propagação de danos no modelo de Ising unidimensional submetido a duas dinâmicas propostas por Hinrichsen e Domany (HD). Em particular, nós estudamos o efeito da atualização síncrona (paralela) e assíncrona (dinâmica contínua) sobre o espalhamento do dano. Mostramos que o dano não se propaga quando a segunda dinâmica é implementada de forma assíncrona. Também mostramos que as regras para atualização do dano produzidas por essa dinâmica, quando a temperatura vai a infinito e um certo parâmetro Lambda é igual a zero, são equivalentes àquelas do bem conhecido autômato celular (modelo A) de Grassberger. / Short-time simulations have been used with great frequency in the literature. That technique was discovered by Li, Shülke and Zheng that, inspired in previous works by Huse and Janssen et al., showed that generalizations of quantities like magnetization and the Binder´s cumulant exhibit universal behavior in the beginning of the simulation (early time behavior). The study of criticality in short-times provides an alternative way to estimate the dynamic critical exponent z, besides allowing the calculation of a new dynamic exponent θ, associated to the anomalous behavior of the magnetization. In the same way, time-dependent simulations became a useful tool to study phase transitions in cellular automata and also for spin models. In fact, the best estimates for the exponent z of the two-dimensional Ising model were obtained through the technique of damage spreading, introduced by Kauffman in the study of cellular automata, later widespread for spin models. In the first part of this work we used short-time Monte Carlo simulations to investigate the Baxter-Wu model, defined in a triangular lattice whose variables are Ising-like coupled by triplet interactions. We have obtained estimates for the dynamic critical exponents z and θ besides static exponents ß e Nû. Our results do not corroborate recent estimates by Santos and Figueiredo for the critical exponent z. In the second part of this work, we investigated the damage spreading in the one-dimensional Ising model under two dynamics introduced by Hinrichsen and Domany (HD). In particular, we study the effects of synchronous (parallel) and asynchronous (continuous dynamics) updating on the spreading properties. We showed that the damage does not spread when the second dynamic is implemented in an asynchronous way. We found that the rules for updating the damage produced by this dynamic, as the temperature goes to infinity and a certain parameter Lambda is zero, are equivalent to those of Grassberger’s well-known model A cellular automaton.

O objetivo da tese foi visualizar como as imagens das cientistas podem estar contribuindo para a manutenção de um panorama predominantemente masculino na ciência, sobretudo nas ciências duras, em razão de estudiosos de gênero terem identificado discriminação sexista como causa da ausência delas na área. Para tal, usamos o suporte teórico da teoria das Representações Sociais de Moscovici para entender a representação de mulher cientista como fenômeno que se modifica através do tempo e as imagens como fatores intervenientes nesse processo de mudança. O esforço do pensamento humano no intuito de entender a visão e as imagens resultou em teorias para explicar as imagens físicas tangíveis, através da compreensão da luz como veículo para mediar as representações que a mente cria, em imagens mentais, por intermédio da captação das imagens físicas nos olhos. Estudamos então como a transformação dessas teorias, através do tempo, culminou no conceito de imagem da ciência moderna, resultado da busca de objetividade de uma ciência em transformação. A culminação paradigmática na ciência moderna criou condições para a naturalização das imagens fotográficas, e pós-fotográficas, como imagens verdadeiras, introduzindo-as como reais, conceito presente nas mentes atuais. Separamos, assim, as imagens em dois grupos: imagens mentais e imagens físicas, para estudar a participação das últimas nas transformações das primeiras; as imagens mentais são entendidas na concepção das representações sociais. Encontramos, assim, na divulgação científica as imagens aliadas às jornalísticas, de cientistas consideradas aqui como reais. Comparando-as com as das películas cinematográficas de ficção, observamos semelhanças e diferenças para concluir como elas interferem na representação da mulher que trabalha com ciência. Em levantamento das imagens, no período de aproximadamente dez anos, de 1996 a 2007, na divulgação cientifica, gênero literário adotado aqui como interface comunicativa entre a Ciência e o senso comum, vê-se que as representações veiculadas, em imagens e textos, têm se metamorfoseado. Na metade da década de 1990, entrevistas com mulheres cientistas enfocavam sua vida doméstica, ressaltando seu duplo pertencimento: privado e público. Atualmente os artigos têm o mesmo teor das entrevistas com cientistas do sexo masculino, focalizando apenas seu trabalho. Dando visibilidade apenas ao que julgam extraordinário, contudo, reforçam as representações sociais de ciência e de cientista como um ser incomum e superdotado, estereótipo já presente no imaginário do senso comum. O cinema reforça isso ao nos oferecer, ao olhar e à interpretação, imagens de cientistas em tramas verossímeis, porém como personagens cuja complexidade tornaas difíceis de serem espelhados como modelos para futuras cientistas. Dessa maneira, as duas mídias acabam se complementando no reforço de uma representação que perpetua o estado de exclusão das mulheres na ciência. Em lugar de dar visibilidade à Ciência como empreendimento e cientista como um trabalhador comprometido com seu labor, ambas as mídias contribuem para manutenção das coisas como estão: uma imagem que contempla o cientista como um ser superior e do sexo masculino, ainda que tenha se ampliado o número de cientistas mulheres. / This thesis objective is to visualize how women scientists images can contribute for the maintenance of a masculine gender panorama in science. This was identified especially on hard sciences, thanks to studies that found sex discrimination as a cause for scientists women absence. Therefore, we use as support the theory of the Social Representations of Moscovici to make clear the representation of woman scientist as phenomenon that modifies through the time, and images as intervening factors in this changing process. The effort of the human thought to understand the vision and the images, resulted in theories to explain the tangible physical images, through the comprehension of the light as a vehicle to mediate the representations that the mind creates, in mental images, by means of the physical images catching in the eyes. We study then, how the transformation of these theories, across the time, culminated in the concept of image in modern science, as a result of the search of objectivity in a mutant science. The paradigmatic culmination in modern science, created conditions for the naturalization of the photographic images, and post photographic, as \"true images\", introducing them as real, a present concept in the current minds. We separate, so, the images in two groups: mental images and physical images, to study the participation of the last ones into the transformations of the first ones; the mental images are understood in the conception of the social representations. We find then, in the scientific diffusion, the images allied to the journalistic ones, of scientists considered here as real. Comparing them with the ones of the fictions cinematographic films, we observe similarities and differences to conclude as they intervene in representation of the woman who works with science. In survey of the images, about the period of ten years, from 1996 to 2007, in the scientific spreading, the literary genre adopted here as communicative interface between Science and the common sense, it can be seen that the representations propagated in images and texts have metamorphosed. At the half of the decade of 1990, interviews with women scientists focused its domestic life, standing out its double belonging: private and public. Currently the papers have the same aspects of the interviews with scientists of the masculine sex, focusing only its work. They give visibility only to that they judge extraordinary, however, they strengthen the social representations of science and scientist as a uncommon and super endowed being, like a stereotype present in the imaginary mind of the common sense. The cinema reinforce it when offers us to see and make interpretation, images of scientists in likely trams, however as personages whose complexity becomes them difficult to be reflected as models for future scientists. By this way, the two medias complement themselves reinforcing a representation that perpetuates the state of exclusion to the women in science. Instead of giving visibility to Science as an achievement and to put the scientist as a worker compromised to its job, both the medias contribute for maintenance of the things as they are: a image that contemplates scientist like a superior being, even there is more women scientists nowadays.

Mathematical modeling of spreading processes have been largely studied in the literature, and its presented a boom in the past few years. This is a fundamental task on the understanding and prediction of real spreading processes on top of a population and are subject to many structural and dynamical constraints. Aiming at a better understanding of this processes, we focused in two task: the modeling and the analysis of both dynamical and structural aspects of these processes. Initially, we proposed a new and general model that unifies epidemic and rumor spreading. Besides, regarding the analysis of these processes, we extended the classical formalism to multilayer networks, in which the theory was lacking. Interestingly, this study opened up new challenges concerning the understanding of multilayer networks. More specifically, regarding their spectral properties. In this thesis, we analyzed such processes on top of single and multilayer networks. Thus, throughout our analysis, we followed three complementary approaches: (i) analytical, (ii) numerical and (iii) simulations, mainly Monte Carlo simulations. Our main results are: (i) a new unifying model, enabling us to model and understand spreading processes on large systems, (ii) characterization of new phenomena on multilayer networks, such as layer-wise localization and the barrier effect and (iii) an spectral analysis of multilayer systems, suggesting a universal parameter and proposing a new analytical tool for its analysis. Our contributions enable further research on modeling of spreading processes, also emphasizing the importance of considering the complete multilayer structure instead of any coarse-graining. Additionally, it can be directly applied on the prediction and modeling real processes. Thus, aside from the theoretical interest and its mathematical implications, it also presents important social impact. / A modelagem matemática dos processos de disseminação tem sido amplamente estudada na literatura, sendo que o seu estudo apresentou um boom nos últimos anos. Esta é uma tarefa fundamental na compreensão e previsão de epidemias reais e propagação de rumores numa população, ademais, estas estão sujeitas a muitas restrições estruturais e dinâmicas. Com o objetivo de entender melhor esses processos, nos concentramos em duas tarefas: a de modelagem e a de análise de aspectos dinâmicos e estruturais. No primeiro, propomos um modelo novo e geral que une a epidemia e propagação de rumores. Também, no que diz respeito à análise desses processos, estendemos o formalismo clássico às redes multicamadas, onde tal teoria era inexistente. Curiosamente, este estudo abriu novos desafios relacionados à compreensão de redes multicamadas, mais especificamente em relação às suas propriedades espectrais. Nessa tese, analisamos esses processos em redes de uma e múltiplas camadas. Ao longo de nossas análises seguimos três abordagens complementares: (i) análises analíticas, (ii) experimentos numéricos e (iii) simulações de Monte Carlo. Assim, nossos principais resultados são: (i) um novo modelo que unifica as dinâmicas de rumor e epidemias, nos permitindo modelar e entender tais processos em grandes sistemas, (ii) caracterização de novos fenômenos em redes multicamadas, como a localização em camadas e o efeito barreira e (iii) uma análise espectral de sistemas multicamadas, sugerindo um parâmetro de escala universal e propondo uma nova ferramenta analítica para sua análise. Nossas contribuições permitem que novas pesquisas sobre modelagem de processos de propagação, enfatizando também a importância de se considerar a estrutura multicamada. Dessa forma, as nossas contribuições podem ser diretamente aplicadas à predição e modelagem de processos reais. Além do interesse teórico e matemático, nosso trabalho também apresenta implicações sociais importantes.

Submitted by (ana.araujo@ufrpe.br) on 2016-08-12T14:04:00Z No. of bitstreams: 1 Rosangela Silveira do Nascimento.pdf: 1012353 bytes, checksum: b5f0d139481ab0bfdd6a1f689175c1f6 (MD5) / Made available in DSpace on 2016-08-12T14:04:00Z (GMT). No. of bitstreams: 1 Rosangela Silveira do Nascimento.pdf: 1012353 bytes, checksum: b5f0d139481ab0bfdd6a1f689175c1f6 (MD5) Previous issue date: 2008-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In the present work we analyze the dynamics of electrical cortical activity during the phenomenon of spreading depression (DA) and during the periods before and after this phenomenon. The characteristic of DA is reduced amplitude of spontaneous electrical activity that occurs in neural tissue after the application of stimulus that can be electrical, chemical, mechanical, luminous etc. In order to study properties of time series of electrical cortical activity recorded by ECoG (electrocortiogram) before,during and after DA, we apply Detrended Fluctuation Analysis(DFA). This method is designed to quantify long term correlations (memory) in temporal series such ECoG register. The method was successfully applied in studies of DNA sequences and non-stationary time series as heart rate variability, stride intervals, financial time series etc. The application of DFA results in scaling exponentα that quantifies correlation properties of nonlinear dynamical systems. This experiment indicates if temporal series posses long term correlations. In this work we calculate exponent α for different intervals: control (before the stimulus), after the stimulus, during the avalanche, during DA and after DA for two experimental groups of rats, nourished and malnourished. For both experimental groups the values of exponent α indicates persistent behavior for all intervals except during the avalanche in which correlations degrade. The presence of long term correlations in physiological time series observed in healthy organisms represents complexity that guaranties the organism’s adaptability to stress and disease. The absence of correlations during the avalanche indicates the loss of this complexity. Non-parametric Wilcoxon test was used to compare mean values of exponents α for all intervals of analyzed time series. In cases of nourished rats, the mean values ofα are significantly different for control, stimulus, avalanche, DA and after-DA intervals. Wilcoxon test was also used to compare mean values of α for corresponding intervals for the two experimental groups. The result is significant difference in mean values of α for control, stimulus avalanche, DA and after DA intervals between two experimental groups. The hypothesis that α =0.5 for avalanche intervals was not rejected by test, confirming the loss of correlations in this phase. Comparison of mean values of α for different intervals (control, stimulus, DA and after DA) with avalanche using the Wilcoxon test results in significant difference between two groups. / O presente estudo se propõe a analisar a dinâmica da atividade elétrica cortical durante o fenômeno da depressão alastrante (DA) e nos períodos que antecede e sucede o fenomêno. A DA é caracterizada pela redução da amplitude da atividade elétrica espontânea que ocorre no tecido neural, após a aplicação de um estímulo de natureza elétrica, química, mecânica, luminosa e outros. Visando estudar o comportamento da série temporal da atividade elétrica cortical, registrada no ECoG (eletrocorticograma), durante a DA e nos períodos que precede e sucede o fenômeno, foi aplicado o método do DFA (Detrended Fluctuation Analysis). Este método permite quantificar a existência de correlação de longo alcance (memória) numa série temporal, como é o caso do registro do ECoG. Anteriormente, o método foi aplicado em seqüências de DNA e no estudo de séries temporais não estacionárias, tais como, dinâmica da variabilidade cardíaca, flutuações de eletroencefalograma de humanos, intervalos entre passos sucessivos de humanos, séries econômicas e outros. A aplicação do DFA numa série temporal permite a determinação de um expoente de escalonamento α, que pode contribuir para a compreensão das propriedades dos sistemas dinâmicos não lineares. Este expoenteα revela se a série temporal apresenta correlação de longo alcance ou não. Neste trabalho os expoentes α foram calculados nas fases de controle, estímulo, avalanche, DA e após a DA para o ECoG, em dois grupos experimentais, ratos nutridos e ratos desnutridos. Em ambos os grupos experimentais, os valores obtidos para o expoente de escalonamento α denotam que a série temporal do ECoG apresenta correlação persistente (comportamento da série no presente se mantém no futuro) em todas as fases do processo com exceção da avalanche, período no qual ocorre perda de correlação. A presença de correlação de longo alcance numa série temporal biológica é uma resposta sempre observada em organismos saudáveis cuja complexidade do sinal registrado garante a adaptabilidade do organismo a situações de estresse e/ou distúrbios. Enquanto a ausência de correlação, observada na avalanche, indica a perda de propriedades fractais nos sistemas fisiológicos. O uso do método não-paramétrico de Wilcoxon, para comparar os valores médios dos expoentes α obtidos para o grupo de animais nutrido, durante as fases de controle, estimulação, DA, após DA, revelou que essas diferentes fasesdiferem significativamente. Os valores médios dos expoentes α obtidos para o grupo de animais desnutrido, durante as fases de controle, estimulação, DA, após DA, também não foram significativamente diferentes, quando comparados pelo método de Wilcoxon. Na comparação dos valores médios de α nas fases de controle, estimulação, DA, após DA entre os dois grupos de animais (nutrido e desnutrido) o teste de Wilcoxon revelou que as médias dos expoentes α em cada fase para os animais nutridos diferem significativamente daquelas obtidas para os animais desnutridos. Na avalanche a hipótese de que o expoente α é igual a 0,5, não foi rejeitada pelo teste de Wilcoxon, ou seja, o teste confirmou a perda de correlação nessa fase. Na comparação entre as médias dos expoentes α nos diferentes intervalos (controle, estimulação, DA, após DA) com o valor do expoente α na avalanche, o teste de Wilcoxon acusou diferença significativa tanto no grupo dos nutridos como no grupo dos desnutridos.