The polymorphonuclear neutrophil granulocytes (neutrophils) are gaining renewed interest regarding their involvement in chronic inflammatory disorders, including rheumatoid arthritis (RA). Besides phagocytic and destructive capabilities, neutrophils have regulatory roles, e.g. by influencing responses from dendritic cells and lymphocytes. Several animal models have revealed that neutrophils are crucial for the initiation and maintenance of chronic inflammatory diseases. Neutrophil function is highly dependent on their ability to produce superoxide, an oxygen radical which can be further metabolized to other free radicals. Whether or not neutrophils are capable of producing the oxygen radical nitric oxide (NO˙) has been a matter of debate. In this thesis it was shown that freshly isolated neutrophils from the joint cavity of patients with RA, but not from other arthritis patients, had ongoing intracellular production of superoxide, indicating the processing of ingested material. The finding that joint neutrophils, but seemingly not circulating cells, expressed the NO-inducing enzyme iNOS, led to a series of experiments aimed to elucidate where in the exudative process this enzyme could first be detected. We could finally, for the first time, present evidence that human neutrophils actually express iNOS constitutively. Our data also suggest that neutrophil iNOS may be membrane associated, thus differing from the cytosolic location in other cell types. Since NOS activity was not demonstrated in isolated cells, the notion that neutrophil iNOS is regulated primarily at the transcriptional level must be questioned. NO production from iNOS requires the presence of its substrate, L-arginine. To test the hypothesis that neutrophil arginase prevents neutrophil NO-production, we investigated whether arginase inhibition affects neutrophil NO-dependent oxidative function. Initial data revealed a difference in the effect of arginase inhibition comparing neutrophil stimulus with a soluble formylated tri-peptide (fMLF) and integrin-mediated stimulation with particle-bound collagen type-1. This led to the hypothesis that integrin-ligation on neutrophils induces extracellular liberation of arginase, which was confirmed both by measuring arginase and its enzyme activity. The findings in this thesis may be important not only regarding the role of neutrophils in chronic joint inflammation, but also as a link in the accelerated atherosclerosis observed in chronic inflammatory disorders, e.g. RA. / Vid reumatiska ledinflammationer ansamlas mycket stora mängder polymorfkärniga neutrofila granulocyter (neutrofiler) inne i den vätskefyllda ledhålan. Neutrofiler har kraftfull destruktiv potential och anses kunna bidra till uppkomst av skada i leden. Då flera djurmodeller av ledinflammation har visat sig omöjliga att initiera i frånvaro av neutrofiler, har intresset för denna celltyp åter ökat efter att de under lång tid har stått i skuggan av andra typer av vita blodkroppar. En viktig del i avdödning av mikroorganismer och cellsignalering är förmågan att bilda fria syreradikaler, t.ex. superoxid (˙O2-) och kväveoxid (NO˙). Denna avhandling belyser aspekter kring produktionen av dessa reaktiva syreprodukter och mekanismer av potentiell betydelse vid ledinflammation. I det första arbetet visas att neutrofiler isolerade ur ledvätska från patienter med ledgångsreumatism (RA) har ett unikt beteende avseende superoxidproduktion jämfört med motsvarande celler från patienter med andra reumatiska sjukdomar. RA-neutrofiler från ledvätska (men inte från blod) producerar superoxid intracellulärt redan i vila och stimulering via vidhäftningsmolekyler ger en snabb ytterligare ökning av denna aktivitet. Fyndet antyder att cellerna är engagerade med hantering av endocyterade partiklar och/eller immunkomplex/immunaggregat. I de båda nästkommande arbetena undersöktes förekomst av det NO˙-producerande enzymet iNOS i neutrofiler. En rad tidigare publikationer har rapporterat motsägelsefulla resultat i denna fråga. Efter en serie experiment kunde vi konstatera att humana neutrofiler uttrycker iNOS konstitutivt, men att både dess cellulära lokalisation och reglering skiljer sig från andra celler. Neutrofiler har nyligen även visats innehålla arginas, ett enzym som konkurrerar med iNOS om bindningen till L-arginin och som därmed kan hämma NO˙-produktion. I det fjärde arbetet undersökte vi därför om hämning av arginas påverkade neutrofilernas funktion och produktion av superoxid. Vi fann att effekterna av arginashämning var större hos celler som stimulerats genom vidhäftning av kollagenklädda partiklar jämfört med en löslig formylerad tri-peptid (fMLF). Vidare, kunde vi visa att vidhäftning av kollagenklädda partiklar medför större extracellulär frisättning av arginas. Med stöd av dessa fynd kunde vi i påföljande försök bekräfta hypotesen att extracellulär frisättning av arginas är större efter vidhäftning av kollagen-partiklar än med fMLF-stimulering. Fysiologiskt är fyndet logiskt då det skulle medföra ökade vidhäftningsmöjligheter för neutrofilen inne i blodbanan genom att begränsa blodkärlets egen NO˙ produktion. Fyndet är också förenligt med den ökade frekvensen hjärt- och kärlsjukdomar vid RA, då en intensiv kontinuerlig utvandring av neutrofiler skulle medföra ökad arginas frisättning, sänkta argininnivåer och endotelial dysfunktion.

Wiederkäuer können entsprechend ihrer Ernährungsgewohnheiten in Rauhfutterfresser, Konzentrat-selektierer und Intermediärtypen eingeteilt werden (HOFMANN 1989). Diese verschiedenen Ernährungstypen spiegeln sich in anatomischen Unterschieden des gesamten Gastrointestinaltraktes, insbesondere jedoch in der Vormagenanatomie wider. Ziel der vorliegenden Arbeit war es, die intrinsische Innervation des Pansens von Wiederkäuern des Rauhfutterfresser- und Intermediärtyps näher zu charakterisieren und mögliche Unterschiede zwischen diesen beiden Ernährungstypen aufzuzeigen. Dafür wurden im ersten Teil der Arbeit die Expression des generellen Neuronenmarkers HuC/D, der Syntheseenzyme Stickstoffmonoxidsynthase (NOS) und Cholinazetyltransferase (ChAT), sowie der Neuropeptide und der neuronalen Marker Neuropeptid Y (NPY), Vasoaktives Intestinales Peptid (VIP), Somatostatin (SOM) und Calbindin (Calb) an Häutchenpräparaten (whole mounts) des myenterischen Plexus aus dem Pansen der Rauhfutterfresser Schaf und Rind und der Intermediärtypen Ziege und Damwild immunhistochemisch untersucht. Desweiteren wurden die Parameter Gangliengröße (Neurone/Ganglion), Gangliendichte (Ganglien/cm² Plexusfläche) und Neuronendichte (Neurone/cm² Plexusfläche) der genannten Spezies tierartlich vergleichend erfasst. Beim Rind fanden sich mit 73±6 Neuronen/Ganglion (Mittelwert ± Standardabweichung) signifikant größere Ganglien als bei den kleinen Wiederkäuern Ziege (57±19), Damwild (51±20) und Schaf (45±18). Demgegenüber war die mittlere Gangliendichte beim Rind mit 6±1 Ganglien/cm² Plexusfläche signifikant geringer als bei Schaf (8±2) und Ziege (10±3), die wiederum eine signifikant geringere Gangliendichte als das Damwild mit 15±3 Ganglien/cm² Plexusfläche aufwiesen. Die Neuronendichte war im ventralen Pansensack von Damwild und Ziege (664±194 bzw. 584±295 Neuronen/cm² Plexusfläche) signifikant höher als beim Schaf (289±132). Die Neuronendichte des Rindes lag mit 432±238 Neuronen/cm² Plexusfläche zwischen den Werten der anderen Spezies. Alle untersuchten myenterischen Neurone waren entweder cholinerg oder nitrerg kodiert. Der relative Anteil nitrerger Neurone pro Ganglion war bei der Ziege (44±10 %) signifikant höher als beim Schaf (30±8 %). Dementsprechend war der relative Anteil cholinerger Neurone beim Schaf signifikant höher als bei der Ziege. Neben den Anteilen unterschied sich auch die Verteilung der nitrergen Neurone in den myenterischen Ganglien. Bei Rind und Ziege waren diese in Clustern am Rand der Ganglien angeordnet, während sie bei Schaf und Damwild locker über die Ganglienfläche verteilt erschienen. Mit Hilfe von Kolokalisationsuntersuchungen konnten bei allen untersuchten Spezies folgende Hauptneuronenpopulationen nachgewiesen werden: ChAT/SP>NOS/NPY/VIP>>ChAT/- und NOS/NPY. Dabei war die cholinerge Hauptpopulation ChAT/SP beim Schaf mit 67±7 % aller myenterischen Neurone signifikant stärker ausgeprägt als beim Damwild (58±11 %), während die nitrerge Hauptpopulation NOS/NPY/VIP bei der Ziege mit 40±9 % signifikant stärker als beim Schaf (26±6 %) ausgeprägt war. SOM und Calbindin fanden sich nur in einer sehr geringen Anzahl (vornehmlich cholinerger) Neurone, wobei SOM–positive Somata nur bei Damwild und Schaf nachgewiesen werden konnten. Im myenterischen Plexus von Rind und Ziege fanden sich ausschließlich Somatostatin-positive Nervenfasern. Im zweiten Teil der Arbeit wurden die Reaktionen von Zirkulärmuskelstreifen aus dem ventralen Pansensack von Schaf und Ziege auf Elektrische Feldstimulation nach Zugabe von Atropin bzw. L-NAME (NG-Nitro-L-Arginine Methylester Hydrochlorid), sowie die Reaktionen auf steigende Konzentrationen von Carbachol funktionell untersucht. Bei beiden Spezies führte Atropin zu verminderten, L-NAME zu verstärkten Kontraktionen als Reaktion auf Elektrische Feldstimulationen. Der muskarinerge Agonist Carbachol führte im Schaf- und Ziegenpansen zu einer konzentrationsabhängigen Steigerung der Motilität. Die Ergebnisse der neurochemischen Untersuchungen lassen auf eine stärkere cholinerge (und somit exzitatorische Kontrolle) des Pansens des Rauhfutterfressers Schaf im Vergleich zu Ziege und Damwild (Intermediärtypen) schließen. Die mikrobielle Fermentation grob strukturierten Rauhfutters erfordert starke, mixende Pansenkontraktionen. Es ist zu vermuten, dass ein höherer Anteil cholinerger myenterischer Neurone auch stärkere Pansenkontraktionen ermöglicht. Somit wäre die starke Ausprägung der cholinergen Innervation im Pansen des Rauhfutterfressers Schaf als eine Anpassung an die physikomechanischen Eigenschaften der bevorzugten Nahrungsquelle Gras zu sehen. Allerdings gelang es in der vorliegenden Arbeit nicht, diese Hypothese durch Unterschiede der in-vitro Motilität an ovinen und caprinen Pansenmuskelstreifen zu untermauern. In scheinbarem Widerspruch zu dieser Hypothese stand auch die nur gering ausgeprägte cholinerge Dominanz bei dem untersuchten großen Rauhfutterfresser Rind. Allerdings könnte diese genetisch bedingt sein, da es sich bei den untersuchten Proben um Material von auf hohe Milchleistung (und damit Konzentratverdaulichkeit) gezüchteten Rinderrassen handelte. Auch ein direkter diätetischer Einfluss auf die intrinsische Panseninnervation scheint in diesem Zusammenhang denkbar. Diese Annahme gründet sich auf Untersuchungen an kleinen Labornagern, bei denen die Aufnahme hoher Energiemengen zu einem Verlust enterischer cholinerger Neurone – und somit zu einem relativ höheren Anteil nitrerger Neurone führt. Deshalb sollte bei allen untersuchten Spezies neben einem möglichen genetischen Einfluss auch der Einfluss der Fütterung nicht außer Acht gelassen werden. Klarheit könnte hier neben vergleichenden Untersuchungen an Extensiv- und Hochleistungsrinderrassen auch die Untersuchung des Einflusses von bestimmten Fütterungsregimen auf die enterische Panseninnervation bringen.

There exists a general consensus in the science education literature around the goal of enhancing students. and teachers. views of nature of science (NOS). An emerging area of research in science education explores NOS and argumentation, and the aim of this study was to explore the effectiveness of a science content course incorporating explicit NOS and argumentation instruction on preservice primary teachers. views of NOS. A constructivist perspective guided the study, and the research strategy employed was case study research. Five preservice primary teachers were selected for intensive investigation in the study, which incorporated explicit NOS and argumentation instruction, and utilised scientific and socioscientific contexts for argumentation to provide opportunities for participants to apply their NOS understandings to their arguments. Four primary sources of data were used to provide evidence for the interpretations, recommendations, and implications that emerged from the study. These data sources included questionnaires and surveys, interviews, audio- and video-taped class sessions, and written artefacts. Data analysis involved the formation of various assertions that informed the major findings of the study, and a variety of validity and ethical protocols were considered during the analysis to ensure the findings and interpretations emerging from the data were valid. Results indicated that the science content course was effective in enabling four of the five participants. views of NOS to be changed. All of the participants expressed predominantly limited views of the majority of the examined NOS aspects at the commencement of the study. Many positive changes were evident at the end of the study with four of the five participants expressing partially informed and/or informed views of the majority of the examined NOS aspects. A critical analysis of the effectiveness of the various course components designed to facilitate the development of participants‟ views of NOS in the study, led to the identification of three factors that mediated the development of participants‟ NOS views: (a) contextual factors (including context of argumentation, and mode of argumentation), (b) task-specific factors (including argumentation scaffolds, epistemological probes, and consideration of alternative data and explanations), and (c) personal factors (including perceived previous knowledge about NOS, appreciation of the importance and utility value of NOS, and durability and persistence of pre-existing beliefs). A consideration of the above factors informs recommendations for future studies that seek to incorporate explicit NOS and argumentation instruction as a context for learning about NOS.

Thèse (M.Serv.soc.)--Université Laval, 2007. / Bibliogr.: f. 97-108. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.

Mestre -- Universidade do Estado do Rio de Janeiro. Instituto de Medicina Social, Rio de Janeiro, 2003.

Orientador : Prof. Dr. Rodrigo Oliveira Soares / Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Sociais Aplicadas, Programa de Pós-Graduação em Contabilidade. Defesa: Curitiba, 27/03/2017 / Inclui referências / Área de concentração: Contabilidade e finanças / Resumo: A demanda por profissionais com maiores conhecimentos advindos da formação acadêmica e da experiência profissional relacionadas a finanças para atuar como Diretor Presidente (Leite, 1997; Manfredi, 1998; Kuenzer, 2002; Rezende, 2002), motiva que os candidatos à essas vagas desenvolvam maior "Sofisticação Financeira". Esses conhecimentos são desejados pelos acionistas, uma vez que os gestores mais sofisticados financeiramente poderiam maximizar sua utilidade em favor do acionista, investindo em projetos mais arriscados. Contudo, a crença excessiva dos acionistas em relação à Sofisticação Financeira do CEO, pode levar esse profissional a superestimar ainda mais suas capacidades e subestimarem seus riscos, aumentando a propensão de que ele apresente os vieses cognitivos excesso de confiança e otimismo (ECO), ou aumentando ainda mais a tendência de apresentar esses desvios cognitivos, já que o fato de assumir cargos financeiros e de gestão estão associados à presença destes vieses (Fischhoff, Slovic, & Lichtenstein, 1977; Barber & Odean, 2001; Kahneman, 2012; Dickel & Moura, 2016). Dessa forma, o presente trabalho teve por objetivo identificar a relação entre a Sofisticação Financeira dos CEO?s e os vieses cognitivos Excesso de Confiança e Otimismo. Para tanto, a amostra deste estudo compreendeu 179 empresas listadas na BM&FBovespa durante os períodos de 2011 a 2015 (excluindo as observações faltantes), totalizando 810 observações. A de Sofisticação Financeira (conceito criado neste estudo) foi mensurada a partir da análise fatorial que permitiu criar o Índice de Sofisticação Financeira (ISF), o qual compreende 7 itens, 3 da dimensão Acadêmica (A) e 4 da dimensão Profissional (P), além disso, foram criados índices para cada uma das dimensões: ISFA e ISFP, a fim de testa-los separadamente. A análise de dados foi conduzida utilizando-se de estatísticas descritivas, correlação de spearman e a regressão linear multivariada (2 modelos: 1 - ISF e 2 - ISFA e ISFP), que considerou as variáveis de controle: CEO Empreendedor (CEOE), CEO Presidente do Conselho da Administração (CEOPCA), Troca de CEO (Troc), Gênero (G), Idade (I), Tamanho (T), Índice Preço/Lucro (IPL), Risco (R) e PIB defasado (PIBt-1). Os resultados do primeiro modelo econométrico indicaram que o ISF não está relacionado com o ECO, no entanto, ao testar o segundo modelo econométrico, o ISFA apresentou-se positiva e significativamente relacionado ao ECO, indicando que os CEO?s que possuem formação internacional, formação financeira e experiência no ramo são propensos a apresentar os desvios cognitivos ECO; diferentemente do ISFP que não apontou significância, além do coeficiente sinalizar o oposto do esperado, apontando que indivíduos com maior ISFP tendem a obter comportamentos isentos dos vieses ECO. Palavras-chave: Índice de Sofisticação Financeira, Índice de Sofisticação Financeira Acadêmica, Índice de Sofisticação Financeira Profissional, Excesso de Confiança, Otimismo. / Abstract: The demand for professionals with greater academic knowledge and professional experience related to finance to act as CEO (Leite, 1997; Manfredi, 1998; Kuzzer, 2002; Rezende, 2002) motivates candidates for these positions to develop greater "Financial Sophistication". Shareholders want this knowledge once more sophisticated financial managers could maximize their utility in favor of the shareholder by investing in riskier projects. However, an overestimation of the CEO's Financial Sophistication belief may lead these professionals to overestimate their capabilities and underestimate their risks, which increases their propensity to exhibit the overconfidence and optimism (OCO) cognitive bias. It may also increase the tendency of these professionals to present these cognitive deviations, since the fact of assuming financial and management positions is associated with the presence of these biases (Fischhoff, Slovic, & Lichtenstein, 1977; Barber & Odean, 2001; Moura, 2016). Thus, the present work aimed to identify the relationship between the CEO's Financial Sophistication and the Overconfidence and Optimism cognitive biases. Therefore, the sample of this study was composed by 179 companies listed on the BM & FBovespa, considering the period from 2011 to 2015 (excluding the missing observations), totaling 810 observations. The Financial Sophistication Index (concept created in this study) was measured using the factorial analysis that allowed the creation of the Financial Sophistication Index (FSI). The FSI comprises 7 items: 3 are related to the Academic dimension (A) and 4 to the Professional dimension (P). In addition, we created indexes for each of the dimensions to test them separately: AFSI and PFSI. Data analysis included descriptive statistics, spearman correlation and multivariate linear regression (2 models: FSI and 2 - FSIA and FSIP), which considered the following control variables: CEO Entrepreneur (CEOE), CEO Chairman (CEOC), CEO Change (CEOCH), Gender (G), Age (A), Size (S), Index Price/Profit (IPL), Risk (R) and Gap-off (Gapt- 1). The results of the first econometric model indicated that FSI is not related to the OCO, however when testing the second econometric model, the AFSI was positively and significantly related to the OCO, indicating that CEOs who had international and financial training and experience in the field are likely to present OCO cognitive deviations; Differently, the PFSI did not achieve statistical significance and its coefficient showed a contrary sign in relation to the expected one, pointing out that individuals with higher PSFI tend to present behaviors exempt from the OCO bias. Keywords: Financial Sophistication Index, Academic Financial Sophistication Index, Professional Financial Sophistication Index, Overconfidence, Optimism.

Made available in DSpace on 2014-06-11T19:26:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-12-11Bitstream added on 2014-06-13T20:47:37Z : No. of bitstreams: 1 pereira_wf_me_sjrp.pdf: 614166 bytes, checksum: 6df9d771c65c6fa8d098e4e0aba88fb5 (MD5) / Neste trabalho estudamos os sistemas dinâmicos caóticos através da definição apresentada por Devaney, composta basicamente de três condições. Investigamos todas as implicações possíveis entre essas condições. Por fim, analisamos o estudo apresentando uma definição mais sucinta e provamos a sua equivalência com a apresentada por Devaney. / In this work we study the chaotic dynamic systems through the definition presented by Devaney, basically composed of three conditions. We investigate all the possible implications among these conditions. Finally, we finish the study presenting briefer definition and prove its equivalence to the one presented by Devaney.

Made available in DSpace on 2015-03-03T11:52:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-08-18Bitstream added on 2015-03-03T12:06:57Z : No. of bitstreams: 1 000807460.pdf: 690788 bytes, checksum: 7d701aa6029006b1052e71fc63c57b89 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Esta pesquisa está vinculada à linha “Infância e Educação” do Programa de Pós-Graduação em Educação da FCT/Unesp, campus de Presidente Prudente e, por esse motivo, investigou os processos educativos, em especial, procurou saber como Hora do Conto é conduzida e desenvolvida no cotidiano escolar, tendo como referência a rotina de duas professoras do 2º ano de séries iniciais do Ensino Fundamental. Dessa maneira, este estudo objetivou compreender e refletir se essa prática contribui e se possui alguma relação com a formação do leitor, tendo como perspectiva teórica, estudos que abrangem a oralidade, contação de histórias, performance e leitura. Nos últimos anos, o Brasil tem ocupado as últimas colocações entre os países com bom desempenho leitor, o que preocupa as autoridades competentes. Desse modo, projetos, como a Hora do Conto e Sala de leitura, vêm sendo implantados nas escolas brasileiras no intuito de solucionar esses índices e, segundo a fala da maioria dos docentes que participam de tais ações, eles podem ser considerados como valiosos instrumentos na formação do leitor. Um bom exemplo é a Hora do Conto, uma vez que o ato de contar histórias para os pequenos possibilita o despertar da imaginação e criatividade, tornando possível a elaboração de conflitos internos e dando oportunidade ao leitor de se situar no mundo e sentir-se parte integrante dele. Neste sentido, o presente projeto de pesquisa teve como objetivos específicos: refletir sobre os aspectos e distinções que permeiam o ler e o contar em sala de aula; identificar se os professores... / Joined to Childhood and Education, a line of work of Faculdade de Ciências e Tecnologia/Universidade Estadual Paulista’s Post-graduate Program in Education, this research investigated educational processes, in particular, sought to understand how the Story Time [Hora do Conto] is conducted and developed in school. In doing so, we followed two second grade teachers and aimed to understand and reflect whether their practices contribute to and have any relationships with the reader’s education. We based on theories about orality, storytelling, performance and reading. In recent years, Brazil has occupied the last positions among other countries concerning good reading performance, which worries the authorities in charge of reading promotion. Thus, projects such as Story Time and Reading Room [Sala de Leitura] are being organized in Brazilian schools in order to solve these problems and, according to the majority of teachers who participate in such actions, they can be considered valuable tools in reader’s education. A good example is the Story Time, since the act of storytelling for children enables the promotion of imagination and creativity, making possible the development of internal conflicts and giving them opportunity to feel they have a space in the world and are part of it. Thus, this research project had the following specific objectives: to reflect on the issues and distinctions that underlie the reading and storytelling in the classroom; to identify if teachers know and use storytelling techniques, if there is a previous planning for this activity; to find out whether during the practice of Story Time the educators...

Orientador: Edson Denis Leonel / Banca: Iberê Luiz Caldas / Banca: Tiago Pereira da Silva / Resumo: Estudamos nessa dissertação algumas propriedades estatísticas no regime de equilibrio pós transitório para o modelo bouncer unidimensional considerando ambas versões completa e simplificada. O modelo consiste de uma partícula clássica movendo-se sob ação de uma força gravitacional constante e sofrendo colisões com uma plataforma móvel de massa muito maior que a massa da partícula. A versão completa leva em conta o movimento real da fronteira e o instante da colisão entre partícula e plataforma é obtido a partir da solução numérica de uma equação transcendental. Já o modelo simplificado, também conhecido como modelo de aproximação de fronteira fixa, assume que para o cálculo do instante da colisão a fronteira está parada, porém a partícula troca energia após a colisão ocorre como se a fonteira estivesse em movimento. Os comportamentos da velocidade média, velocidade quadrática média e desvio da velocidade quadrática média foram obtidos em função dos parâmetros de controle. Desenvolvemos um método semi-analítico permitindo-nos deduzir equações dos valores médios sem fazer simulações de larga escala. Em seguida, elaboramos uma simulação do tipo Monte-Carlo que nos permite obter os valores médios no estado estacionário sem resolver equações transcendentais, acelerando assim as simulações numéricas. O método de Monte-Carlo apresentado pode ser útil na investigação de sistemas mais complexos incluindo bilhares clássicos dependentes do tempo / Abstract: We studied some statistical properties in the stationary and post transitory state for the one-dimensional bouncer model considering wither complete and simplified versions. The model consists of a classical particle moving under the effect of a constant gravitational force and collides with a periodic moving platform whose mass is heavier as compared to the particle. The complete version takes into account the real motion of the moving wall. The instant of collision is obtained from the numerical solution of a transcendental equation. The simplified version, also called as a static wall approximation, takes into account to calculate the instant of the collisions as if the wall was fixed. However, the particle experiences an exchange of energy and momentum at the collision as if the wall were moving. The behavior for the average velocity, average squared velocity and deviation of the average squared velocity were obtained as a function of the control parameters. We developed a semi-analytic method allowing us to deduce equations for the average values without the need of doing large scale simulations. Using a Monte-Carlo-like simulation we obtained the average values for the stationary state without solving the transcendental equations. The Monte-Carlo method may have applications in the investigation of more complex systems including time dependent billiard systems / Mestre

Orientador: Marcelo Messias / Banca: Paulo Ricardo da Silva / Banca: João Carlos da Rocha Medrado / Banca: Regilene Delazaridos Santos Oliveira / Banca: Fábio Scalco Dias / Resumo: Neste trabalho, consideramos aspectos algébricos e dinâmicos de alguns problemas envolvendo superfícies algébricas invariantes em sistemas diferenciais polinomiais definidos em R³. Determinamos o número máximo de planos invariantes que um sistema diferencial quadrático pode ter e estudamos a realização e integrabilidade de tais sistemas. Fornecemos a forma normal para sistemas diferenciais com quádricas invariantes e estudamos de forma mais detalhada a dinâmica e integrabilidade de sistemas diferenciais quadráticos com um paraboloide elíptico como superfície algébrica invariante. Por fim, estudamos as consequências dinâmicas ao se perturbar um sistema diferencial, cujo espaço de fase é folheado por superfícies algébricas invariantes. Para tal, consideramos o sistema diferencial quadrático conhecido como sistema Sprott A, que depende de um parâmetro real a e apresenta comportamento caótico mesmo sem ter pontos de equilíbrio, tendo, assim, um hidden attractor para valores adequados do parâmetro a. Provamos que, para a=0, o espaço de fase desse sistema é folheado por esferas concêntricas invariantes. Utilizando a Teoria do Averaging e o Teorema KAM (Kolmogorov-Arnold-Moser), provamos que, para a>0 suficientemente pequeno, uma órbita periódica orbitalmente estável emerge de um equilíbrio do tipo zero-Hopf não isolado localizado na origem e que formam-se toros invariantes em torno desta órbita periódica. Concluímos que a ocorrência de tais fatos tem um papel importante na formação... / Abstract: In this work, we consider algebraic and dynamical aspects of some problems involving invariant algebraic surfaces in polynomial differential systems defined in R³. We determine the maximum number of invariant planes that a quadratic differential system can have and we study the realization and integrability of such systems. We provide the normal form for differential systems having an invariant quadric and we study in more detail the dynamics and integrability of quadratic differential systems having an elliptic paraboloid as invariant algebraic surface. Finally, we study the dynamic consequences of perturbing differential system whose phase space is foliated by invariant algebraic surfaces. For this we consider the quadratic differential system known as Sprott A system, which depends on one real parameter a and presents chaotic behavior even without having any equilibrium point, thus having a hidden attractor for suitable values of parameter a. We prove that, for a=0, the phase space of this system is foliated by invariant concentric spheres. By using the Averaging Theory and the KAM (Kolmogorov-Arnold-Moser) Theorem, we prove that, for a>0 sufficiently small, an orbitally stable periodic orbit emerges from a zero-Hopf nonisolated equilibrium point located at the origin and that invariant tori are formed around this periodic orbit. We conclude that the occurrence of these facts has an important role in the formation of the hidden attractor. / Doutor