Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2015-05-08T14:05:16Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 1 Dissertação - João Vitor Nogueir.pdf: 7740367 bytes, checksum: e311056ecafb8741fc3538682907dcc1 (MD5) / Made available in DSpace on 2015-05-08T14:05:16Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 1 Dissertação - João Vitor Nogueir.pdf: 7740367 bytes, checksum: e311056ecafb8741fc3538682907dcc1 (MD5) Previous issue date: 2014-01-30 / A instabilidade de Saffman-Taylor se dá na interface entre dois fluidos viscosos no interior de uma célula de Hele-Shaw (CHS). A CHS é um aparato experimental que consiste em duas placas, usualmente planas e paralelas, separadas por uma distância muito pequena. Sabe-se que quando um fluido viscoso desloca outro mais viscoso, em uma CHS, a interface entre eles se torna instável e estruturas chamadas de “dedos viscosos” surgem. Em função da geometria da CHS e da força motriz do fluxo, tais dedos podem bifurcar, afinar, competir em tamanho e interferirem uns com os outros, formando as mais diversas estruturas morfológicas. Estudos com fluidos newtonianos em CHS vêm sendo feitos desde o final do século XIX. No entanto, apenas recentemente, a cerca de trinta anos, estudos com fluidos não newtonianos em CHS vêm sendo conduzidos, e em sua maioria estudos analíticos lineares ou não lineares puramente numéricos. Este trabalho tenta preencher essa lacuna com um estudo analítico não linear de fluidos não newtonianos em CHS. Estudamos a CHS de geometria radial com levantamento da placa superior e injeção como forças motrizes do fluxo. Nestes casos estudamos o fluido yield stress, um tipo especial de fluido não newtoniano que se comporta como um “semissólido”. Estudamos também o fluido power-law que introduz, na viscosidade, uma dependência do fluxo. Em cada caso fomos capazes de estabelecer conexões entre as nossas previsões teóricas e os experimentos e simulações encontrados na literatura. Tais previsões são acerca da estabilidade e morfologia da interface como: bifurcação de dedos, a estrutura conhecida como side branching e a competição entre dedos.

Nesta dissertação aplicamos conceitos de Teoria de Jogos Evolucionária ao jogo Hawk-Dove introduzido originalmente por Maynard Smith como um modelo para lutas convencionais [37]. Estudamos então a competição entre estratégias puras (consistentes) e mistas/aleatórias (inconsistentes) em uma extensão deste jogo que, sujeita a efeitos estocásticos, apresenta um mecanismo de drift que leva à população a um equilíbrio monomórfico da estratégia inconsistente. Também estudamos o problema do altruísmo forte e os efeitos de uma demografia de grupos em sua evolução, baseado no framework 2LFW de Schonman, Vicente e Caticha [58]. Elaboramos uma fórmula para a probabilidade de extinção do processo em seus estágios iniciais e calculamos e simulamos os equilíbrios estáveis do framework no regime de seleção fraca em t ! 1 para alguns jogos de interesse. / In this dissertation we have applied Evolutionary Game Theory concepts to the Hawk-Dove game that has been originally introduced by Maynard Smith as a model for conventional aggression [37]. We then studied the competition between pure (consistent) and mixed/random (inconsistent) strategies in an extension of this game which, subject to stochastic effects, presents a drift mechanism that drives the population to a monomorphic equilibrium of the inconsistente strategy. We have also studied the problem of Strong Altruism and the effects of a group demography in its evolution, based on Schonman, Vicente and Catichas 2LFW framework [58]. We have elaborated a formula for the processs extinction probability in its initial stages and calculated and simulated the stable equilibriums of the framework under weak selection for t ! 1 for some games of interest.

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Dans cette thèse sont présentées plusieurs études relatives aux désintégrations de mésons Bd et Bs en trois corps sans charme avec un KS dans l'état final.Ces analyses portent sur des données collectées par l'expérience LHCb durant le Run I du LHC, et qui correspondent à une luminosité intégrée de 3 fb-1.Une première analyse consiste à la mesure des rapports d'embranchements des modes B(d,s) -> KSh+h'-, ou h(') désigne un kaon ou un pion.Les mesures précédemment effectuées par LHCb de ces rapports d'embranchement, relativement à celui du mode Bd->KSpi+pi-, sont actualisées.Le but principal de cette analyse est la recherche du mode Bs -> KSK+K-, qui n'a jamais encore été observé.Les rapports d'embranchements, relativement à celui de Bd -> KSpi+pi-, sont mesurés : B(Bs->KSpi+pi-)/B(Bd->KSpi+pi-) = 0.26 +/- 0.04(stat.) +/- 0.02(syst.) +/- 0.01(f_s/f_d) B(Bd->KSKpi)/B(Bd->KSpi+pi-) = 0.17 +/- 0.02(stat.) +/- 0.00(syst.) B(Bs->KSKpi)/B(Bd->KSpi+pi-) = 1.84 +/- 0.07(stat.) +/- 0.02(syst.) +/- 0.04(f_s/f_d) B(Bd->KSKK)/B(Bd->KSpi+pi-) = 0.59 +/- 0.02(stat.) +/- 0.01(syst.)Une première observation de Bs->KSK+K-, correspondant à une significance globale de 3.7 sigmas, est effectuée.Une analyse du plan de Dalitz indépendante du temps et sans étiquetage de saveur du canal Bd -> KSK+K- est effectuée en utilisant l'approche isobare.Les rapports d'embranchement des désintégration quasi-deux-corps des canaux Bd->KS phi, Bd->KS f'2(1525) et Bd->KS chic0 sont mesurés.Ils sont compatibles avec des mesures précédentes effectuées par Babar. / This dissertation presents several studies of the decays of both Bd and Bs mesons to charmless three-body final states including a KS meson.They use the data recorded by the LHCb experiment during Run I of LHC, corresponding to an integrated luminosity of 3 fb-1.A first analysis consists of the measurement of the branching fractions of B(d,s)->KSh+h'- decays, where h(') designates a kaon or a pion.Preceding LHCb measurements of branching fractions for all decay channels, relative to that of Bd->KSpi+pi-, are updated.Furthermore, the primary goal of this analysis is to search for the, as yet, unobserved decay Bs->KSK+K-.The relative branching fractions are measured to be: B(Bs->KSpi+pi-)/B(Bd->KSpi+pi-) = 0.26 +/- 0.04(stat.) +/- 0.02(syst.) +/- 0.01(f_s/f_d) B(Bd->KSKpi)/B(Bd->KSpi+pi-) = 0.17 +/- 0.02(stat.) +/- 0.00(syst.) B(Bs->KSKpi)/B(Bd->KSpi+pi-) = 1.84 +/- 0.07(stat.) +/- 0.02(syst.) +/- 0.04(f_s/f_d) B(Bd->KSKK)/B(Bd->KSpi+pi-) = 0.59 +/- 0.02(stat.) +/- 0.01(syst.) A first observation of Bs->KSK+K- is reported with a global significance of 3.7 sigmas.A flavour-untagged, time-independent Dalitz-plot analysis of Bd->KSK+K- is presented, using the isobar approach.The quasi-two-body branching fractions of Bd->KS phi, Bd->KS f'2(1525), and Bd->KS chic0 are measured.They are compatible with previous measurements from Babar.

Cette thèse est consacrée à l'étude de décompositions trajectorielles de processus de Lévy spectralement positifs et des relations de dualité pour des processus de ramification, motivée par l'utilisation de ces derniers comme modèles probabilistes d'une dynamique épidémiologique. Nous modélisons l'arbre de transmission d'une maladie comme un arbre de ramification, où les individus évoluent indépendamment les uns des autres, ont des durées de vie i.i.d. (périodes d'infectiosité) et donnent naissance (infections secondaires) à un taux constant durant leur vie. Le processus d'incidence dans ce modèle est un processus de Crump-Mode-Jagers (CMJ) et le but principal des deux premiers chapitres est d'en caractériser la loi conjointement avec l'arbre de transmission partiellement observé, inferé à partir des données de séquences. Dans le Chapitre I, nous obtenons une description en termes de fonctions génératrices de la loi du nombre d'individus infectieux, conditionnellement à l'arbre de transmission reliant les individus actuellement infectés. Une version plus élégante de cette caractérisation est donnée dans le Chapitre II, en passant par un résultat général d'invariance par retournement du temps pour une classe de processus de ramification. Finallement, dans le Chapitre III nous nous intéressons à la loi d'un processus de ramification (sous)critique vu depuis son temps d'extinction. Nous obtenons un résultat de dualité qui implique en particulier l'invariance par retournement du temps depuis leur temps d'extinction des processus CMJ (sous)critiques et de l'excursion hors de 0 de la diffusion de Feller critique (le processus de largeur de l'arbre aléatoire de continuum). / This dissertation is devoted to the study of some pathwise decompositions of spectrally positive Lévy processes, and duality relationships for certain (possibly non-Markovian) branching processes, driven by the use of the latter as probabilistic models of epidemiological dynamics. More precisely, we model the transmission tree of a disease as a splitting tree, i.e. individuals evolve independently from one another, have i.i.d. lifetimes (periods of infectiousness) that are not necessarily exponential, and give birth (secondary infections) at a constant rate during their lifetime. The incidence of the disease under this model is a Crump-Mode-Jagers process (CMJ); the overarching goal of the two first chapters is to characterize the law of this incidence process through time, jointly with the partially observed (inferred from sequence data) transmission tree. In Chapter I we obtain a description, in terms of probability generating functions, of the conditional likelihood of the number of infectious individuals at multiple times, given the transmission network linking individuals that are currently infected. In the second chapter, a more elegant version of this characterization is given, passing by a general result of invariance under time reversal for a class of branching processes. Finally, in Chapter III we are interested in the law of the (sub)critical branching process seen from its extinction time. We obtain a duality result that implies in particular the invariance under time reversal from their extinction time of the (sub)critical CMJ processes and the excursion away from 0 of the critical Feller diffusion (the width process of the continuum random tree).

<p>U radu su prvi put za proveru teorija nastajanja i gumolike elastičnosti polimernih mreža primenjeni modelni poliuretanski sistemi čiji su čvorovi veoma stabilni izocijanurat(heksahidro-1,3,5-triazin- 2,4,6-trion) prstenovi. Rad obuhvata: (1) Sintetezu nekoliko serija homogenih poli(uretan-izocijanuratnih) mreža, na bazi 2.4-TDI i poli(oksipropilen)diola, dvoetapnim postupkom u masi, tj. ciklotrimerizacijom teleheličnih diizocijanata uz katalizator Polycat 41. (2) Sintezu manje savr&scaron;enih mreža sa nekom definisanom koncentracijom visećih lanaca koja je postignuta uvodenjem monoola dietilenglikol- monometiletra u toku pripreme prepolimera. (3) Odredivanje povoljnih reakcionih uslove svih etapa sinteze uz primenu i modifikaciju postojećih analitičkih postupaka za karakterizaciju svojstava reakcionih komponenti i praćenja reakcija umrežavanja. (4) Procenu mogućih bočnih reakcija u toku nastajanja mreža jer one mogu značajno uticati na raspodelu različitih fragmenata u mrežama praćenjem koncentracija reakcionih proizvoda kod modelnih reakcija u rastvoru uz isti diol i isti katalizator i odgovarajuće mono-funkcionalne izocijanatne komponente. (5) Karakterizaciju svojstava i strukturnih parametara modelnih mreža i to primenom postupaka ekstrakcije i bubrenja, diferencijalne skanirajuće kalorimetrije, fotoelastičnih merenja, dinamičko-mehaničke spektroskopije i merenja napon-istezanje. Izborom nominalne Mn diola od 400 do 4000 postigne gustina umreženja 0.1x10^-4mol/cm³ do 10x10^-4mol/cm³ sa rasponom temperatura staklastog prelaza od -60&deg;C do +30&deg;C. Za procenu strukturnih parametara mreža primenjena je teorija granajućih procesa sa kaskadnom zamenom za slučaj nastajanja mreža ciklotrimerizacijom i dvoetapni postupak. U zavisnosti od konverzije NCO grupa u mrežama izračunate su masa po monomernoj jedinici, maseni udeo, broj po monomernoj jedinici, koncentracija po jedinici zapremine, Mn, Mw, Mz i Mw/Mn kako za elastično aktivne, osnovne i viseće lance tako i zamolekule sola. Ključni ekspehmentalni podaci koji su kori&scaron;ćeni za proveru teorija nastajanja bio sadržaj gela dobijen vi&scaron;estrukim ekstrakcijama, a za teorije gumolike elastičnosti ravnotežni modul dobijen iz fotoelastičnih merenja. Provera teorija gumolike elastičnosti se zasnivala se u nalaženje vrednosti pred- faktora 3 (tzv. faktora pamćenja) u jednačini koja daje vezu ravnotežnog modula elastičnosti i koncentracije elastično aktivnih lanaca mreže koji ukazuje na način fluktuacije cvorova mreže. Fotoelastična merenja su omogućila da se preko njih parameter pred-faktor 3 proceni pri malim deformacijama. Potvrden je koncept stvarnih mreža sa delimično potisnutim fluktuacijama čvorova uz aditivni doprinos zapletenosti lanaca modulu elastičnosti prema Langley-Graesley konceptu zarobljenih prepletaja.</p> / <p>In this thesis polymer network formation theories and rubber elasticity of polymer networks on model polyurethane systems having as a junction very stable isocyanurate(hexahidro-1,3,5-tгiazin-2,4,6- trion) rings are for the first time investigated. The work contains: (1) Synthesis of homogenious series of several poly(urethane-isocyanurate) networks based on poly(oxypropylene)diol and 2.4-TDI by two stages procedures in bulk i.e. cyclotrimerization of telechelic diisoicyanates with Polycat 41 as catalyst. (2) Synthesis of less perfect networks with some concentration of dangling chains obtained by introduction of monofunctional component diethyleneglycolmonomethylether during prepolymer formation. (3) Determination of optimal reaction conditions for both stages of the synthesis. (4) Estimation of possible side reaction during network formation because of theirs important influence on nework fragment distribution. (5) Caracterization of networks structure and properties by swelling and multiply extraction, differential scanning calorimetry, photoelastical measurements, dynamic-mechanical spectroscopy and stress-strain measurements. By using the different Mn of diols (400 - 4000) the network density from<br />0.1x10^-4mol/cm³ to 10x10^-4mol/cm³ and glass transition temperatures from -60&deg;C to +30&deg;C was achieved. For network structure determinations the theory of branching processes with cascade substitution was used. Mass per monomer unit, mass fraction, number per monomer unit, concentration per unit volume, Mn, Mw, Mz and Mw/Mn for elastically active network chains, backbone chains, dangling chains and sol molecules In the dependence on NCO groups conversion are calculated. Crucial experimental data for examination of network formation theories was the gel content and for rubber<br />elasticity theories the equilibrium modulus received from photoelastical measurement. The estimation of rubber elasticity theories was based on the analysis of the front factor 3 in the equation which gives the relation between the equilibrium modulus and concentration of elastically active network chains. It is estimated the additive contribution of chain entanglements to the equilibrium modulus, especially in the case of high networks density according to Langley-Graesley theory of trapped entanglements.</p>

In this thesis, we use multitype Galton-Watson branching processes in random environments as individual-based models for the evolution of structured populations with both demographic stochasticity and environmental stochasticity, and investigate the phenotype allocation problem. We explore a variational characterization for the stochastic evolution of a structured population modeled by a multitype Galton-Watson branching process. When the population under consideration is large and the time scale is fast, we deduce the continuous approximation for multitype Markov branching processes in random environments. Many problems in evolutionary biology involve the allocation of some limited resource among several investments. It is often of interest to know whether, and how, allocation strategies can be optimized for the evolution of a structured population with randomness. In our work, the investments represent different types of offspring, or alternative strategies for allocations to offspring. As payoffs we consider the long-term growth rate, the expected number of descendants with some future discount factor, the extinction probability of the lineage, or the expected survival time. Two different kinds of population randomness are considered: demographic stochasticity and environmental stochasticity. In chapter 2, we solve the allocation problem w.r.t. the above payoff functions in three stochastic population models depending on different kinds of population randomness. Evolution is often understood as an optimization problem, and there is a long tradition to look at evolutionary models from a variational perspective. In chapter 3, we deduce a variational characterization for the stochastic evolution of a structured population modeled by a multitype Galton-Watson branching process. In particular, the so-called retrospective process plays an important role in the description of the equilibrium state used in the variational characterization. We define the retrospective process associated with a multitype Galton-Watson branching process and identify it with the mutation process describing the type evolution along typical lineages of the multitype Galton-Watson branching process. Continuous approximation of branching processes is of both practical and theoretical interest. However, to our knowledge, there is no literature on approximation of multitype branching processes in random environments. In chapter 4, we firstly construct a multitype Markov branching process in a random environment. When conditioned on the random environment, we deduce the Kolmogorov equations and the mean matrix for the conditioned branching process. Then we introduce a parallel mutation-selection Markov branching process in a random environment and analyze its instability property. Finally, we deduce a weak convergence result for a sequence of the parallel Markov branching processes in random environments and give examples for applications.

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<div>In this thesis we study two different types of self-interacting random walks. First, we study excited random walk in a deterministic, identically-piled cookie environment under the constraint that the total drift contained in the cookies at each site is finite. We show that the walk is recurrent when this parameter is between -1 and 1 and transient when it is less than -1 or greater than 1. In the critical case, we show that the walk is recurrent under a mild assumption on the environment. We also construct an environment where the total drift per site is 1 but in which the walk is transient. This behavior was not present in previously-studied excited random walk models.</div><div><br></div><div>Second, we study the "have your cookie and eat it'' random walk proposed by Pinsky, who already proved criteria for determining when the walk is recurrent or transient and when it is ballistic. We establish limiting distributions for both the hitting times and position of the walk in the transient regime which, depending on the environment, can be either stable or Gaussian.</div>