Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / In this work, we study some parameters of monophonic convexity in some classes of graphs and we present our results about this subject. We prove that decide if the $m$-interval number is at most 2 and decide if the $m$-percolation time is at most 1 are NP-complete problems even on bipartite graphs. We also prove that the $m$-convexity number is as hard to approximate as the maximum clique problem, which is, $O(n^{1-varepsilon})$-unapproachable in polynomial-time, unless P=NP, for each $varepsilon>0$. Finally, we obtain polynomial time algorithms to compute the $m$-convexity number on hereditary graph classes such that the computation of the clique number is polynomial-time solvable (e.g. perfect graphs and planar graphs). / Neste trabalho, estudamos alguns parÃmetros para a convexidade monofÃnica em algumas classes de grafos e apresentamos nossos resultados acerca do assunto. Provamos que decidir se o nÃmero de $m$-intervalo à no mÃximo 2 e decidir se o tempo de $m$-percolaÃÃo à no mÃximo 1 sÃo problemas NP-completos mesmo em grafos bipartidos. TambÃm provamos que o nÃmero de $m$-convexidade à tÃo difÃcil de aproximar quanto o problema da Clique MÃxima, que Ã, $O(n^{1-varepsilon})$-inaproximÃvel em tempo polinomial, a menos que P=NP, para cada $varepsilon>0$. Finalmente, apresentamos um algoritmo de tempo polinomial para determinar o nÃmero de $m$-convexidade em classes hereditÃrias de grafos onde a computaÃÃo do tamanho da clique mÃxima à em tempo polinomial (como grafos perfeitos e grafos planares).

Submitted by (ana.araujo@ufrpe.br) on 2016-08-08T13:46:53Z No. of bitstreams: 1 Mariese Conceicao Alves dos Santos.pdf: 4420169 bytes, checksum: adcd8009d419cc6d3c5188eb75cd346d (MD5) / Made available in DSpace on 2016-08-08T13:46:53Z (GMT). No. of bitstreams: 1 Mariese Conceicao Alves dos Santos.pdf: 4420169 bytes, checksum: adcd8009d419cc6d3c5188eb75cd346d (MD5) Previous issue date: 2011-06-03 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The foot and mouth disease (FMD) is a disease that attacks all cloven-hoofed animals, especially cattle, pigs, sheep and goats. It is characterized by blistering and considered the most serious of all infections. It is generated by at least seven serotypes of viruses that cause infections indistinguishable. The spread is associated with the movement of infected animals and their contact with susceptible animals. In this thesis a model was proposed which aimed to find an index of risk of transmission of foot and mouth disease virus between cattle farms across a network. It comprises two levels, the first will be analyzed the point process F generated from the xi ∈ A ⊂ R2 randomly selected points and the stochastic process Yxi,tj , the level of infection wich through it is done the location of the occurrence of infection by the FMD virus, called a focus of infection. The second level is a percolation model G(G, P), in wich G = G(F,E) is a graph, F a set of farms and E represents the edges that connect the farms. And P is the probability that transmission occurring. By uniting the two levels arises G′(G′, P′), in that G′ consists of F′ the union of all the farms to the set F focus F, and E′ the union of E edges with new edges connecting F and F. And P′ is formed by the set of values of P and Pi,l, the probability of farm Fi be infected by a foco fl. Points were simulated representing the cartesian coordinates of the farms and herd size, the points were distributed randomly and regularly on the network. Were also simulated the relative initials positions of the focus in a random form on the network, in the center, edges and vertices, considering three areas of study region A. The results showed that there are no difference for the two types network and they confirm the impact of the relative initial position of the focus on the network to a spread of infection in a number of farms, these results were shown when compared to three areas of A. / A Febre aftosa (FA) é uma enfermidade que ataca a todos os animais de casco fendido, principalmente bovinos, suínos, ovinos e caprinos. Ela é caracterizada pela formação de vesículas e considerada a mais grave de todas infecções. É gerada por pelo menos sete sorotipos de vírus que causam infecções indistinguíveis. A propagação está associada com o movimento de animais infectados e o seu contato com animais suscetíveis. Nesta dissertação foi proposto um modelo que teve como objetivo encontrar um índice de risco de transmissão pelo vírus da febre aftosa (VFA) entre fazendas de rebanho bovino através de uma rede. Ele é formado por dois níveis, no primeiro será analisado o processo pontual F, gerado a partir de pontos xi ∈ A ⊂ R2 sorteados aleatoriamente e do processo estocástico Yxi,tj , o nível de infecção, que através dele é feita a localização da ocorrência da infecção pelo vírus da febre aftosa, chamado de focus de infecção. O segundo nível é um modelo de percolação G(G, P), em que G = G(F,E) é um grafo, F um conjunto de fazendas e E representando as arestas que ligam as fazendas. E P é a probabilidade dessa transmissão ocorrer. Com a união dos dois níveis surge G′(G′, P′), em que G′ ´e formado por F′, a união do conjunto de fazendas F ao conjunto de focus F, e E a união das arestas E com as novas arestas ligando F a F. E P′ é formado pelo conjunto de valores de P e por Pi,l, a probabilidade da fazenda Fi ser infectada por um foco fl. Foram simulados pontos representando as coordenadas cartesianas das fazendas e o tamanho do rebanho, os pontos foram distribuídos de forma aleatória e regular na rede. Também foram simuladas as posições relativas iniciais dos focus de forma aleatória na rede, no centro, nas bordas e nos vértices, considerando 3 áreas da região de estudo A. Os resultados mostraram que não há diferença para os dois tipos de rede e confirmam o impacto da posição relativa inicial dos focus na rede para uma propagação da infecção em um conjunto de fazendas, esses resultados também foram mostrados quando comparados para 3 áreas de A.

Red rice (Oryza spp.) is one of the main limiting factors of rice yield (O. sativa L.) in the world and particularly in the Rio Grande do Sul (RS) state Brazil. The Clearfield® technology is a viable and efficient tool for controlling such harmful plant by using imidazolinone herbicides in tolerant cultivars. However, herbicides may persist on the soil after the crop season in amount that could affect the future use of the area with other crops as well as with non tolerant rice cultivars. The persistence of this kind of herbicides is highly dependent on the soil s environmental conditions. It increases in low pH soils with high organic matter (MO) content, and under anaerobic conditions. The main way of herbicide dissipation is the biodegradations; they can be photolysis or be lixiviated bellow the roots absorption region. Two field experiments were carried out on lowland soil in Santa Maria-RS during 2006/2007. The first experiment (Chapter II) had the objective of determining the effect of nine soil tillages (four on no till or minimum till seeping and five, on conventional tillage) on the phytotoxicity of non tolerant rice. The residual effect of the herbicide Only® affected plants stand, tillering, panicle number and plant heights of cultivar IRGA 417, but did not affect the grain yield. Soil plowing decreased herbicide activity on the soil surface (0-3 cm) without affecting the variables assayed. The second experiment (Chapter III) had the objective of determining the effect of two soil tillages (no till- PD- and conventional tillage-PC) on imazethapyr degradation and leaching. Higher degradation of imazethapyr was registered on PC than on PD. Imazethapyr leaching until 20 cm regardless the tillage system. In PC, a uniform distribution of imazethapyr was observed in the first 15 cm of soil while in PD there was a lower concentration of imazethapyr at 0-5 cm, which accumulated at 5-15 cm deep. / O arroz-vermelho (Oryza spp.) é um dos principais fatores limitantes da produtividade de grãos do arroz irrigado (O. sativa L.) no mundo e em particular do estado do Rio Grande do Sul (RS) Brasil. A tecnologia Clearfield® é uma ferramenta viável e eficiente para o controle desta planta daninha, mediante o uso de herbicidas da família das imidazolinonas junto com cultivares tolerantes a estes herbicidas. No entanto, os herbicidas podem permanecer no solo após o cultivo, em quantidade que pode comprometer a utilização futura da área com outras culturas, ou mesmo com cultivares de arroz não tolerante (NT). A permanência destes herbicidas no solo é muito dependente das condições ambientais e de solo, aumentando sua persistência em solos com pH baixos, com altos conteúdos de matéria orgânica (MO), argila e em condições de anaerobioses. A principal via de dissipação destes herbicidas é a microbiana, podendo também, sofrer fotólises ou serem lixiviados para fora da área de absorção das raízes. Foram conduzidos dois experimentos sob solo de várzea, em Santa Maria-RS no ano agrícola 2006/07. O primeiro experimento (Capítulo II) teve como objetivo determinar o efeito de nove manejos de solo (quatro sob plantio direto ou semidireto e cinco sob plantio convencional), na fitotoxicidade do arroz não tolerante. O efeito residual do herbicida Only® afetou o estande de plantas, perfilhamento, número de panículas e a estatura da cultivar não tolerante IRGA 417, porém não afetou a produtividade de grãos. O revolvimento do solo diminuiu a atividade do herbicida na camada superficial de solo (0-3 cm), embora não tenha afetado as variáveis analisadas. O segundo experimento (Capítulo III) teve como objetivo determinar o efeito de dois manejos de solo, plantio direto (PD) e plantio convencional (PC), na degradação e lixiviação do imazethapyr. Ocorreu maior degradação de imazethapyr no PC do que no PD. Imazethapyr lixiviou até 20 cm, independente do sistema de cultivo. No PC existe uma distribuição uniforme do imazethapyr nos primeiros 15 cm de solo e no PD existe menor concentração de imazethapyr de 0-5 cm, e acúmulo do herbicida de 5-15 cm de profundidade.

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Orientador: Sandro Guedes de Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-26T18:12:34Z (GMT). No. of bitstreams: 1 Vasconcellos_HerminianeLuizade_M.pdf: 4238996 bytes, checksum: 69965aad9e9748e349be6894c6ebf385 (MD5) Previous issue date: 2015 / Resumo: Este trabalho baseia-se na analise de descritores de heterogeneidade de dose atraves de programas desenvolvidos em linguagem C++ com base na estatistica de Poisson e probabilidades de ocorrencia de heterogeneidade fundamentadas na teoria de percolacao. A finalidade deste trabalho e obter descritores que possam ser uteis no estudo de efeitos biologicos da radiacao caracteristicos de situacoes em que ha heterogeneidade de dose. Os suportes iniciais deste trabalho se encontram em um relatorio da International Comission on Radiation Units and Measurements, que aborda as questoes de heterogeneidade de dose. Particulas ¿¿ e reacoes envolvendo interacao com neutrons sao as radiacoes que foram focadas na dissertacao e base da aplicacao dos programas desenvolvidos, atraves de resultados obtidos de um experimento em um acelerador linear Elekta Synergy, inter-calibrado com simulacoes de calculo de Monte Carlo. A teoria de percolacao que estuda o comportamento de aglomerados em redes bidimensionais e tridimensionais e baseada em processos randomicos, e pode ser aplicada porque eventos gerados pelas reacoes nucleares ou espalhamentos com neutrons que obedecem a estatistica de Poisson. Os eventos gerados podem ser mapeados a procura de aglomerados, celulas que sao vizinhas nas quais tenham ocorrido eventos. Os aglomerados sao a base da construcao dos descritores. Os resultados encontrados demonstram que os indices de heterogeneidades utilizados fornecem informacoes importantes a respeito da formacao destes aglomerados. Foram comparados os resultados obtidos para os casos 2D e 3D de distribuicao de celulas hipoteticas e foi possivel estudar as relacoes entre os dois casos. Os descritores de heterogeneidade possibilitarao associacoes de dano biologico com a distribuicao de eventos em culturas celulares (caso 2D) e tecidos (caso 3D) / Abstract: The goal of this study is the analysis of dose heterogeneity descriptors through programs developed in C ++ language based on Poisson statistics and probabilities for the occurrence of heterogeneity based on percolation theory. The purpose of this study is to obtain descriptors that may be useful in the study of radiobiological effects characteristic of the situations in which there is dose heterogeneity. The initial support for this work is the report by the International Commission on Radiation Units and Measurements, which describes the dose heterogeneity issues. Álpha particles and reactions involving interaction with neutrons were focused on this thesis are the base of application programs developed from results of an experiment at a linear accelerator Elekta Synergy, inter-calibrated with Monte Carlo simulation. The percolation theory, a theory that studies cluster behavior in two and three-dimensional lattices, is based on random processes, can be applied because the events generated by nuclear reactions with neutrons follow the Poisson statistics. Generated events can be mapped in the search for clusters, neighbor cells in which events occurred. The clusters are the basis for construction of descriptors. The results show that the heterogeneity descriptors provide important information about clusters formation. The results for 2D and 3D cases were compared for distribution of hypothetical cells. and it was possible to study the relations between the two cases. The descriptors of heterogeneity enable biological damage associations with the distribution of events in cell culture (2D case) and tissues (3D case) / Mestrado / Física / Mestra em Física

Orientador: Élcio Lebensztayn / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-27T03:09:48Z (GMT). No. of bitstreams: 1 UtriaValdes_JaimeAntonio_M.pdf: 525263 bytes, checksum: 3a980748a98761becf1b573639a361c1 (MD5) Previous issue date: 2015 / Resumo: O Resumo poderá ser visualizado no texto completo da tese digital / Abstract: The Abstract is available with the full electronic digital document / Mestrado / Estatistica / Mestre em Estatística

Dans cette thèse, on étudie un système de particules en interaction qui généralise un processus de contact, évoluant en environnement aléatoire. Le processus de contact peut être interprété comme un modèle de propagation d'une population ou d'une infection. La motivation de ce modèle provient de la biologie évolutive et de l'écologie comportementale via la technique du mâle stérile, il s'agit de contrôler une population d'insectes en y introduisant des individus stérilisés de la même espèce: la progéniture d'une femelle et d'un individu stérile n'atteignant pas de maturité sexuelle, la population se voit réduite jusqu'à potentiellement s'éteindre. Pour comprendre ce phénomène, on construit un modèle stochastique spatial sur un réseau dans lequel la population suit un processus de contact dont le taux de croissance est ralenti en présence d'individus stériles, qui forment un environnement aléatoire dynamique. Une première partie de ce document explore la construction et les propriétés du processus sur le réseau Z^d. On obtient des conditions de monotonie afin d'étudier la survie ou la mort du processus. On exhibe l'existence et l'unicité d'une transition de phase en fonction du taux d'introduction des individus stériles. D'autre part, lorsque d=1 et cette fois en fixant l'environnement aléatoire initialement, on exhibe de nouvelles conditions de survie et de mort du processus qui permettent d'expliciter des bornes numériques pour la transition de phase. Une seconde partie concerne le comportement macroscopique du processus en étudiant sa limite hydrodynamique lorsque l'évolution microscopique est plus complexe. On ajoute aux naissances et aux morts des déplacements de particules. Dans un premier temps sur le tore de dimension d, on obtient à la limite un système d'équations de réaction-diffusion. Dans un second temps, on étudie le système en volume infini sur Z^d, et en volume fini, dans un cylindre dont le bord est en contact avec des réservoirs stochastiques de densités différentes. Ceci modélise des phénomènes migratoires avec l'extérieur du domaine que l'on superpose à l'évolution. À la limite on obtient un système d'équations de réaction-diffusion, auquel s'ajoutent des conditions de Dirichlet aux bords en présence de réservoirs. / In this thesis, we study an interacting particle system that generalizes a contact process, evolving in a random environment. The contact process can be interpreted as a spread of a population or an infection. The motivation of this model arises from behavioural ecology and evolutionary biology via the sterile insect technique ; its aim is to control a population by releasing sterile individuals of the same species: the progeny of a female and a sterile male does not reach sexual maturity, so that the population is reduced or potentially dies out. To understand this phenomenon, we construct a stochastic spatial model on a lattice in which the evolution of the population is governed by a contact process whose growth rate is slowed down in presence of sterile individuals, shaping a dynamic random environment. A first part of this document investigates the construction and the properties of the process on the lattice Z^d. One obtains monotonicity conditions in order to study the survival or the extinction of the process. We exhibit the existence and uniqueness of a phase transition with respect to the release rate. On the other hand, when d=1 and now fixing initially the random environment, we get further survival and extinction conditions which yield explicit numerical bounds on the phase transition. A second part concerns the macroscopic behaviour of the process by studying its hydrodynamic limit when the microscopic evolution is more intricate. We add movements of particles to births and deaths. First on the d-dimensional torus, we derive a system of reaction-diffusion equations as a limit. Then, we study the system in infinite volume in Z^d, and in a bounded cylinder whose boundaries are in contact with stochastic reservoirs at different densities. As a limit, we obtain a non-linear system, with additionally Dirichlet boundary conditions in bounded domain.

The catalycal oxidation of hydrogen sulphide in presence of small amounts of hexan has been investigated over a Titania catalyst. H2S is converted into sulphur. Nevertheless the catalyst undergoes a deactivation through coke formation. In order to explain the coke profile in the inner of the catalyst's pellet, the influence of the internal heat and mass transfers has been considered using a pore network. / Die katalytische Oxydation von Schwefelwasserstoff auf einem TiO2-Anatase-Katalysator wird in Anwesenheit von n-Hexan durchgeführt. Schwefel wird gebildet. Der Katalysator unterliegt jedoch eine schnelle Deaktivierung durch Russbildung, die anhand eines Porennetzwerksmodells simuliert werden wird. Sowohl Stoff- als auch Wärmetransport werden berücksichtigt.

Electroconductive silicate-based composites are advanced materials that allow building structures to perform several different functions simultaneously. Addressing the issues of their development and use is a suitable topic for research work. The aim of this work is to study the effect of structure on the resistivity of silicate composite. The structure of electrically conductive composites is studied on dry cement paste and mortar mixtures as well as on test bodies made of hardened cement paste and mortar after 28 days of curing. Based on the analysis of the raw materials, six suitable electroconductive fillers are selected based on particle size, resistivity, and water absorption. The parameters of dry cement paste and hardened cement paste with replacement of 4-19 wt. % cement by the selected fillers are determined. Two of the fillers are selected for use in dry and hardened mortar. Resistivity is determined for all dry mixes and hardened composites variants, and percolation thresholds are approximately determined. By studying the structure of the selected variants, it is shown that the most important parameters that have the greatest influence on the resistivity of the silicate composites are mainly the particle size and the intrinsic resistivity of the electrically conductive filler. For silicate composites in the hardened state, the volume of hydration products, especially portlandite and C-S-H gels, also has a significant influence. For both dry blends and hardened composites, it was found that the smaller the particle size of the electroconductive filler, the smaller the representation needed to reach the percolation threshold. Portlandite and C-S-H gels in the volume of the hardened composite cause its high resistivity. The resistivity of the hardened composite is always higher than that of the dry blends. Thus, the proportion of electroconductive filler needed to reach the percolation threshold is higher in hardened composites than in dry mixes. The resist

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