Ziel dieser Arbeit war es, den zentralen Kohlenstoffwechsel mit besonderem Fokus auf Regulation zu untersuchen, insbesondere durch die Auftrennung von zwei Regulationsebenen: metabolische Regulation, assoziiert mit direkten Wech- selwirkungen zwischen Metaboliten und Enzymen, sowie hierarchische Regulation, assoziiert mit Änderungen in Enzymmengenänderungen durch die Regulation von de novo Enzymproduktion. Unsere Untersuchungen basieren größtenteils auf drei Datensätzen aus glukoselimitierten Chemostatkulturen von S. cerevisiae. Im Kap. 2 wurden Extrazelluläre Bedingungen im Makroskopischen unter- sucht. Das wichtigsten Ergebnis dieser the- oretischen Analyse ist die Charakterisierung des Selektionsdruckes in einem Chemostatkultur. Im Kap. 4 wurde eine Analyse auf Systemebene des zentralen Kohlenstoffwech- sels durchgeführt. Unter Verwendung der Metaboliten- und der Flußdaten wurde ein kinetisches Modell konstruiert, welches wesentliche Teile des zentralen Kohlen- stoffwechsels umfaßt. Die meisten kinetischen Ausdrücke und Parameterwerte wurden aus einem bestehenden kinetischen Modells (Teusink-Modell) übernom- men. / In this work, we aimed to elucidate central carbon metabolism focusing on the aspect of regulation, especially by separating two regulatory levels: metabolic regulation, associated with direct interactions of metabolites and enzymes, and hierarchic regulation, associated with enzyme level change via regulation of de novo enzyme production. Our investigations were largely based on the analysis of three datasets from glucose limited continuous cultures of S. cerevisiae. Extracellular conditions on the macroscopic scale were investigated in Chapter 2. This was inspired by the perceived lack of clarity regarding an important aspect: concentration of glucose, the limiting nutrient and main carbon source in these cultures. The main outcome of this theoretical analysis was characterisation of the selection pressure in a chemostat culture, as selecting for cells which produce the growth rate, defined by the pre-set dilution rate, with lower external concentration of the limiting nutrient. Flux regulation on the scale of individual enzymes was investigated for selected reactions in Chapter 3. This analysis was based on the attempt to reproduce flux changes through these reactions, using enzyme kinetic expressions with inputs from the three aforementioned datasets. The notion of hierarchic and metabolic regulation was introduced and modified. System-level analysis of central carbon metabolism was undertaken in Chap- ter 4. Using the information on metabolite levels and flux, a kinetic model representing significant parts of central carbon metabolism was constructed. To get feasible flux distributions, constrained metabolic flux balance analysis was performed, using a stoichiometric network, constructed to be consistent with the model’s stoichiometry. Fitting the model resulted in two sets of parameters corresponding to steady states reproducing, the nominal data values of the anaerobic and the fully aerobic conditions.

A necessidade de pensar novas metodologias para o ensino da matemática, especialmente a partir de temas relacionados ao cotidiano dos alunos, motivou a realização deste trabalho que, através da modelagem matemática, tem como objetivo aliar teoria e prática no contexto da educação básica, para verificar o tempo que uma pessoa, fazendo uso adequado do fator de proteção solar (FPS) 30, pode ficar exposta à radiação ultravioleta (UV) do Sol, sem sofrer queimaduras. O estudo indica ainda os contributos desta pesquisa, apresenta uma proposta para o ensino “tempo de exposição segura ao sol”, que permite ao professor do ensino médio tratar de conceitos de função exponencial de maneira crítica e reflexiva, para a construção de um conhecimento mais significativo e também fornece aos alunos condições de perceber a integração da matemática com outras áreas do conhecimento proporcionando, através da modelagem matemática, condições necessárias para que ele possa desenvolver estudos que possibilitem maior capacidade de analisar, participar e agir sobre o conhecimento que está sendo construído. Ao considerar os níveis de radiação, o FPS 30 em relação ao tipo de pele, os dados remetem a uma função exponencial, que ao se aplicar a metodologia do método dos mínimos quadrados possibilitou elaborar um modelo matemático para cada um dos quatro tipos de pele. Os resultados mostram que se as pessoas fizerem o uso correto do FPS 30, a depender do tipo de pele, é possível permanecer em exposição ao sol por um período mínimo de 1h e 45 minutos, sem sofrer queimaduras. / The necessity of thinking about new methodologies to the mathematics teaching, especially from themes related to the student’s everyday life, motivated this project achievement that through mathematical modelling has as purpose to ally theory and practice in the basic education context, to verify the time that one person that makes appropriate use of sun protection factor (SPF) 30, can be exposed to ultraviolet radiation (UR) of the sun without suffering sunburn. The study also indicates the contributions of this research, presents a proposal to the teaching time of safe exposure to the sun, that allow to the high school teacher discuss concepts of exponential function in a critical and reflexive way to a more significant knowledge construction and provides to the student’s conditions to realize the integration of the mathematics with others knowledge areas providing through the mathematical modelling, necessary conditions that the student can develop studies that enable more capacity of analyzing, participate and act about the knowledge that is being constructed. Considering the radiation levels, the SPF 30 in relation to the skin type, the data remit to the exponential function, that applying the ordinary least squares method makes possible elaborate a mathematical model for each one of the four types of skin. The results show that if people make the right use of the SFP 30, depending on the skin type, it is possible to stay in sun exposure for a minimum period of 1h and 45 minutes, without being burned.

Dentre os insetos que causam prejuízo a produção de soja, os percevejos fitófagos destacam-se como o principal grupo de pragas, sendo Euschistus heros (Fabricius, 1798), atualmente, a principal espécie de praga da cultura, que está distribuída em todas as regiões brasileiras de cultivo da leguminosa. Para o controle das populações destes insetos, o método mais utilizado é o controle químico. No entanto, as exigências tem sido crescentes no que diz respeito à redução do uso de agroquímicos. Dentre as alternativas, o uso dos parasitoides de ovos Telenomus podisi Ashmead, 1881 e Trissolcus basalis Wollaston, 1858 emerge com bom potencial para programas de controle biológico. O uso desses agentes de controle deve ser baseado em estudos que assegurem a eficiência dos insetos no manejo da população da praga. O presente estudo combina experimentação laboratorial e de campo com modelagem matemática para investigar o potencial dos parasitoides como controladores do percevejo da soja. Foram realizados estudos relacionados aos parâmetros biológicos e potenciais reprodutivos de T. podisi e T. basalis através de tabelas de vida de fertilidade. Foram determinadas as exigências térmicas de ambos os parasitoides de ovos e observou-se o efeito da idade dos ovos de E. heros no parasitismo por T. podisi e T. basalis. Foi também avaliada a interação entre as duas espécies de parasitóides e determinado o número ideal de cada espécie de parasitoide a ser liberado de acordo com a densidade de ovos do hospedeiro. Finalmente um modelo matemático foi proposto visando simular interações e liberações em parasitoides, para o controle de E. heros. Com a combinação entre os experimentos e a implementação de metodologia analítica através de modelagem ecológica espera-se incrementar estratégias de controle da praga, para fundamentar a recomendação do uso do parasitoide mais eficiente para controlar E. heros, ou mesmo a melhor forma de combinar o o uso das espécies de inimigos naturais. / Among insects causing damage to soybean production, stink bugs appear as the main group of pests to control Euschistus heros (Fabricius, 1798), currently, is the major pest of soybean, distributed for all brazilian regions. To control these insect populations, the most common method is the use of chemicals. However, the demand for reducing the use of insecticides has been increasing. Therefore, the interest in using the parasitoids Telenomus podisi Ashmead, 1881 and Trissolcus basalis Wollaston, 1858 has increased. The use of these control agents must be based on studies that ensure their efficiency in the management of pest population. In this study it were conducted studies to assess biological parameters and the reproductive potential of T. podisi and T. basalis by focusing on fertility life tables. It was determined the thermal requirements of both egg parasitoids and observed the effect of E. heros egg age on the parasitism by T. podisi and T. basalis. It was also evaluated the interaction between the two parasitoids. In addition, it was determined the optimal number of parasitoids to be released according to the host eggs density. A mathematical model was proposed in order to simulate interactions among parasitoids, and release them to be used to control of E. heros. By making experiments and implementing analytical methodology associated to ecological modelling we expected to improve the pest control strategies in order to recommend the use of the most efficient parasitoid species to control E. heros, or even to use different species combining them.

Um estudo foi realizado com os objetivos de (i) avaliar o desempenho produtivo, característica de rendimento de carcaça e impacto econômicos de frangos de corte; (ii) demonstrar a utilização de modelos de superfície de resposta em um programa não-linear de formulação de ração para otimização do lucro; e (iii) desenvolver uma planilha dinâmica e interativa para determinar a idade de abate de frangos de corte que otimiza o retorno econômico. Para atender esses objetivos, um experimento foi conduzido, no período de 1 a 56 dias, utilizando 1080 pintos de um dia, Ross®, distribuídos em delineamento em blocos casualizados com seis tratamentos de seis repetições de 30 aves cada. Os tratamentos foram arranjados em esquema fatorial com três densidades nutricionais (baixa, moderada ou alta) por sexos (machos ou fêmeas). Os resultados do desempenho produtivo avaliado, mostraram que a alta densidade nutricional promove melhor desempenho produtivo, entretanto, prejudica os resultados econômicos. Para o fator sexo, as fêmeas apresentam piores resultados de desempenho e econômicos em relação aos machos, no entanto, melhoram o rendimento de peito. No segundo estudo, os modelos de superfície de resposta construídos para as variáveis dependentes consumo de ração e peso corporal para cada sexo e fase de criação foram adequados para estimar o desempenho produtivo e a receita líquida. Além disso, o programa não linear de formulação de ração pode ser útil por otimizar respostas nutricionais e econômicas com precisão. O terceiro estudo fornece uma planilha que usa uma abordagem interativa e dinâmica para determinar a idade de abate que otimiza o lucro da produção baseado no cenário econômico. Os usuários podem calcular a idade ótima de mercado e analisar a decisão de lucro máximo usando diferentes combinações de custos, função de crescimento, equação de consumo de ração e peso de mercado aceitável. Assim, a planilha pode ser aplicada como uma ferramenta de gestão em tempo real para auxiliar na tomada de decisões, otimizar a produtividade animal e maximizar o lucro. / An experiment was conducted with the objective of (i) evaluating the productivity, yield functionality and economic impact of broilers; (ii) demonstrate the use of response surface models in a nonlinear feed formulation program for profit optimization; and (iii) develop a dynamic and iterative programming to determine the optimal slaughter age of broilers that optimizes the profit. For these objectives, an experiment was conducted over a period of 1 to 56 days using 1080 one-day-old Ross® chicks were distributed in a randomized block design with six treatments and six repetitions of 30 birds each. The treatments were arranged in a factorial scheme with three nutritional densities (low, moderate or high) by two sexes (males or females). The production results were evaluated, that high nutritional density promotes optimal productive performance, although it hinders the economic results. Regarding the sex factor, the females showed poor results regarding performance and profit when compared to the males. Nevertheless, they exhibited improved breast meat yields. In the second study, the response surface models were constructed can be used to estimate the productive performance, and therefore the net revenue. In addition, the nonlinear programming of feed formulation can be useful by optimizing nutritional and economic responses accurately. It was concluded that the response surface models are efficient in predicting the performance of broilers and allow to formulate diets to maximize profits. The third study, a dynamic and iterative programming was development for to determine the age slaughter for maximum profit. The model calculated net revenue, consumption ration and market weight. These results could represent a valuable reference for use in adjusting the strategy for broiler production and management. Thus, the developed programming can be applied as a real-time management tool, to aid in decision-making, optimize the productivity and maximize profit.

L’objectif de cette thèse est de développer des modèles mathématiques de perception visuelle basés sur des architectures corticales et de les appliquer pour reproduire des expériences phénoménologiques ainsi que pour traiter des images naturelles. Nous nous concentrons sur les tâches de vision de bas niveau et nous sommes intéressés par le problème du groupement et de l’individuation des unités perceptives. Nous ferons face au problème de la reconstruction des figures illusoires et de la détection des vaisseaux rétiniens dans les images optiques. Ensuite, nous considérerons le problème du codage et du décodage de l’activité cérébrale du cortex visuel obtenue par Imagerie par Résonance Magnétique fonctionnelle (IRMf). Ceci permet d’estimer la structure du cortex d’un patient spécifique et éventuellement de reconstruire le stimulus visuel de l’activité IRMf, dans une stratégie “de lecture du cerveau”. La distinction entre notre approche et l’état de la littérature consiste à utiliser des modèles neuromathématiques du cortex comme connaissance a priori pour régulariser la structure estimée. Même si c’est un objectif à long terme, nous proposons une première approche pour améliorer les résultats dans ce domaine. L’ensemble du travail de cette thèse a été développé en tenant compte des résultats de la phénoménologie de la perception et des résultats de la neurophysiologie. Dans le domaine de la phénoménologie de la perception, au début du siècle dernier, la théorie de la psychologie de la Gestalt a défini l’intégration des contours et en particulier Wertheimer [1938], Kohler [1947], Kofka [1935] ont défini le regroupement des lois de perception. Celles-ci sont cruciales dans la construction d’objets visuels : les éléments avec des caractéristiques en commun peuvent être regroupés pour former un nouvel objet visuel plus grand. Des expériences psychophysiques ont été proposées pour mesurer les paramètres quantitatifs de ces lois. Un intérêt particulier de cette thèse est le concept de champ d’association introduit par Field et al. [1993] lequel code différents principes de la Gestalt (dont la bonne continuation et la proximité).Ces auteurs ont montré que la co-linéarité de stimulus et la co-circularité jouent un rôle important dans la caractéristique du groupement. Leur étude a montré comment les chances de percevoir un chemin curviligne étaient élevées si l’orientation de ses éléments était tangente à ce chemin. D’autre part, en neurophysiologie, une grande quantité d’expériences confirment que le problème du groupement et de détection des contours est effectué par le cortex visuel primaire (V1) [Hubel, 1995]. Un cadre mathématique, basé sur les instruments différentiels, a été introduit pour formaliser ces résultats. Les premiers modèles géométriques sont dus à Koenderink and van Doorn... / The objective of this thesis is to develop mathematical models of visual perception based on cortical architectures and to apply them to reproduce phenomenological experiments and to process natural images. We primarly focus on low level vision tasks and in particular we are interested in the problem of grouping and of individuation of perceptual units. In this setting we will face the problem of the reconstruction of illusory figures and the detection of retinal vessels in optical images. Then we consider the problem of encoding and decoding of the fMRI signal from in vivo acquired brain activity of visual cortex. This allows to estimate the structure of the cortex of a specific human patient and eventually to reconstruct the visual stimulus from fMRI activity, in a so called “brain reading” strategy. The difference between our approach and the state of the art literature consists in using previously defined neuromathematical models of the cortices as a-priori knowledge to regularise in vivo estimated structure. Even if it is a long term objective, we propose a first approach to improve the results in this field. The entire work of this thesis has been developed taking into account results from phenomenology of perception and results of neurophysiology.In the field of the phenomenology of perception, at the beginning of the last century, the theory of the Gestalt psychology [Wertheimer, 1938, Kohler, 1947, Kofka, 1935] defined the integration of contours and in particular they defined grouping laws underlying perception. These are crucial in the construction of visual objects: points with characteristics in common can be grouped together to form a new visual object. Many psychophysical experiments have been proposed to measure the quantitative parameters of these laws. A particular interest of this thesis is the concept of association fields introduced by Field et al. [1993] which encodes different Gestalt principles (as good continuation, proximity). They showed that stimulus co-linearity and co-circularity play an important role for the feature of grouping. Their study showed how chances of perceiving the curvilinear path were high if the orientation of its features was the one tangent at that point and collapsed as their relative orientation deviated from being tangent...

Primeiramente, esse trabalho pretende esclarecer a importância de pesquisas em modelagem, simulação e controle nos processos de tratamento de efluentes e apontar o atraso do Brasil nesta área de pesquisa comparado ao avanço das iniciativas internacionais. O trabalho apresenta o problema específico da modelagem dos processos anaeróbios e propõe uma nova ferramenta de simulação de regime permanente para esses sistemas, desde digestores de lodo a reatores UASB. O simulador se baseia no ADM1 (Anaerobic Digestion Model No 1), modelo proposto pela IWA em 2002, e está implementado em C++. A intenção é disponibilizar livremente um software de simulação com o diferencial de uma metodologia e interface gráfica amigável, capaz de trazer para o dia-a-dia do profissional da área toda a sofisticação de uma modelagem mais completa, tanto do ponto de vista microbiológico como físico-químico. A metodologia proposta se mostrou muito eficiente para a obtenção da condição de regime permanente, fazendo com que a caracterização do afluente se tornasse a etapa limitante do processo de simulação. O método desenvolvido é tão eficaz que permite que sejam realizadas simulações com afluentes e reatores hipotéticos, tornando possível estudos desvinculados da necessidade de análises laboratoriais complexas ou fora do comum. / First, this work intends to show the importance of research in modeling, simulation and control of wastewater treatment processes, and to point the delay of our country (Brazil) in this subject, compared to the advance of the international initiatives. This work presents the specific problem of modeling the anaerobic digestion and proposes a new tool to simulate the steady state condition in anaerobic reactors. The simulator is based on the ADM1 (Anaerobic Digestion Model No 1), developed by IWA in 2002, and is implemented in C++. The intention is to give free access to a new simulation software with the advantages of better methodology and friendly graphical interface. This tool should be able to bring to the professionals all the sophistication of a more complete modelling in the microbiological and physical-chemical point of view. The developed methodology revealed itself to be very efficient for the attainment of the steady state condition. Consequently, it makes the characterization of the influent the critic stage of the simulation process. The developed method is so efficient that allows simulation studies to be carried out using hypothetical influents and reactors. Thus, it brings independence for simulation studies with no need of complex or unusual laboratorial analyses.

Um estudo foi realizado com os objetivos de (i) avaliar o desempenho produtivo, característica de rendimento de carcaça e impacto econômicos de frangos de corte; (ii) demonstrar a utilização de modelos de superfície de resposta em um programa não-linear de formulação de ração para otimização do lucro; e (iii) desenvolver uma planilha dinâmica e interativa para determinar a idade de abate de frangos de corte que otimiza o retorno econômico. Para atender esses objetivos, um experimento foi conduzido, no período de 1 a 56 dias, utilizando 1080 pintos de um dia, Ross®, distribuídos em delineamento em blocos casualizados com seis tratamentos de seis repetições de 30 aves cada. Os tratamentos foram arranjados em esquema fatorial com três densidades nutricionais (baixa, moderada ou alta) por sexos (machos ou fêmeas). Os resultados do desempenho produtivo avaliado, mostraram que a alta densidade nutricional promove melhor desempenho produtivo, entretanto, prejudica os resultados econômicos. Para o fator sexo, as fêmeas apresentam piores resultados de desempenho e econômicos em relação aos machos, no entanto, melhoram o rendimento de peito. No segundo estudo, os modelos de superfície de resposta construídos para as variáveis dependentes consumo de ração e peso corporal para cada sexo e fase de criação foram adequados para estimar o desempenho produtivo e a receita líquida. Além disso, o programa não linear de formulação de ração pode ser útil por otimizar respostas nutricionais e econômicas com precisão. O terceiro estudo fornece uma planilha que usa uma abordagem interativa e dinâmica para determinar a idade de abate que otimiza o lucro da produção baseado no cenário econômico. Os usuários podem calcular a idade ótima de mercado e analisar a decisão de lucro máximo usando diferentes combinações de custos, função de crescimento, equação de consumo de ração e peso de mercado aceitável. Assim, a planilha pode ser aplicada como uma ferramenta de gestão em tempo real para auxiliar na tomada de decisões, otimizar a produtividade animal e maximizar o lucro. / An experiment was conducted with the objective of (i) evaluating the productivity, yield functionality and economic impact of broilers; (ii) demonstrate the use of response surface models in a nonlinear feed formulation program for profit optimization; and (iii) develop a dynamic and iterative programming to determine the optimal slaughter age of broilers that optimizes the profit. For these objectives, an experiment was conducted over a period of 1 to 56 days using 1080 one-day-old Ross® chicks were distributed in a randomized block design with six treatments and six repetitions of 30 birds each. The treatments were arranged in a factorial scheme with three nutritional densities (low, moderate or high) by two sexes (males or females). The production results were evaluated, that high nutritional density promotes optimal productive performance, although it hinders the economic results. Regarding the sex factor, the females showed poor results regarding performance and profit when compared to the males. Nevertheless, they exhibited improved breast meat yields. In the second study, the response surface models were constructed can be used to estimate the productive performance, and therefore the net revenue. In addition, the nonlinear programming of feed formulation can be useful by optimizing nutritional and economic responses accurately. It was concluded that the response surface models are efficient in predicting the performance of broilers and allow to formulate diets to maximize profits. The third study, a dynamic and iterative programming was development for to determine the age slaughter for maximum profit. The model calculated net revenue, consumption ration and market weight. These results could represent a valuable reference for use in adjusting the strategy for broiler production and management. Thus, the developed programming can be applied as a real-time management tool, to aid in decision-making, optimize the productivity and maximize profit.

Estudamos a dinâmica de formação de bolhas em fluidos viscosos. Desenvolvemos novas técnicas experimentais para aprofundar o estudo do sistema de um bico borbulhador no fundo de um cilindro preenchido por uma solução de água e glicerina. Neste sistema, controlamos o fluxo de ar por meio de um fluxímetro de massa e uma válvula solenoide. Medimos simultaneamente: o tempo entre duas bolhas sucessivas usando um laser focalizado em um foto- diodo, cuja luz é espalhada com a passagem das bolhas; as ondas de pressão que o borbulhamento causa no sistema de injeção usando microfones colocados entre a válvula solenoide e o bico; e a geometria das bolhas em formação, através da análise de imagens coletadas por uma câmera de alta velocidade. Motivados pelos resultados deste sistema, construímos um modelo para a dinâmica de formação de bolhas, baseado em primeiros princípios, que descreve a rota de adição de períodos observada no experimento. Investigamos também um novo sistema experimental, que tem dois bicos borbulhadores dentro do mesmo tubo. Usamos as mesmas técnicas experimentais desenvolvidas para o experimento de um bico. Identificamos que os borbulhamentos sincronizam apesar de seus sistemas de injeção de ar serem independentes, concluímos, portanto, que o acoplamento deve-se à circulação que o líquido introduz. Estudamos a sincronização por meio da construção de diagramas de bifurcação e espaços de parâmetros mostrando as regiões de sincronização. Adaptamos também o modelo de um bico para descrever este sistema. Descobrimos que a interação entre as duas dinâmicas de formação de bolhas é maior conforme aumentamos a altura da coluna líquida. / We studied the bubble formation dynamics in viscous fluids. We developed new experimental techniques to provide a better understanding of the system with one bubbling nozzle on the bottom of a cylinder filled with a water and glycerol solution. In this system, we control the air flow with a mass flowme- ter and a solenoid valve. We have measured simultaneously: the time between successive bubbles, using a laser focused in a photo-diode that has his light scattered when one bubble passes between them; the pressure waves that the bubbling causes in the air injecting system using microphones placed between the solenoid valve and the nozzle; and the geometry of the growing bubbles, through the analysis of the images collected by a high speed camera. The re- sults from this system motivated us to make a model for the bubbles formation dynamics that describes the period-adding route observed in the experiment and is based on first principles. We also investigated a new experimental system, that has two bubbling nozzles inside the same cylinder. We used the same experimetal techniques developed to the one nozzle experiment. We identified that the bubbling on the nozzles synchronizes due the coupling introduced by the liquid circulation, as the air injecting systems are independent. We studied the synchronization by constructing bifurcation diagrams and parameter spaces that show the syn- chronized regions. We also adapted the one nozzle bubbling model to decribe this system. We discovered that the interaction between the two bubble forma- tion dynamics is stronger when we increase the liquid height.

Orientador: Victor José Mendes Cardoso / Banca: Fábio Socolowski / Banca: Gustavo Habermann / Resumo: A germinação de sementes representa uma etapa crítica para a sobrevivência da maioria das fanerógamas. Composição de gases, temperatura e água são os principais fatores ambientais limitantes do processo de germinação. Entre esses, a temperatura e a água exibem maior grau de flutuação, tanto em escala temporal como espacial, no ambiente terrestre, funcionando como importantes sinalizadores ambientais para a semente. Os objetivos deste trabalho foram fornecer a caracterização básica dos padrões germinativos de quatro cultivares (Carioca comum, Iapar 81, IPR Graúna e IPR Uirapuru) de Phaseolus vulgaris L. (Fabaceae); determinar as faixas ótimas de germinação para cada cultivar (experimentos em gradiente térmico com água destilada); realizar experimentos com interação dos fatores temperatura e potencial osmótico com soluções de polietilenoglicol 6000, visando à aplicação de modelos matemáticos baseados nos conceitos de graus-dia, psi-dia e na combinação destes dois conceitos (modelo psi-graus-dia), para se efetuar a comparação da resposta germinativa de tais cultivares. A cultivar IPR Graúna apresentou a faixa ótima com maior variação de distintas temperaturas (nove temperaturas), baseando-se na velocidade média de germinação; contrastando com a Iapar 81, que não apresentou uma faixa ótima, mas sim um único ponto ótimo (32,6ºC). Nenhuma das quatro cultivares apresentou germinação acima de 38,2ºC nem abaixo de 10,3ºC nos experimentos em gradiente térmico (água destilada). As temperaturas base obtidas pelo modelo de graus-dia variaram de 8,4 a 9,2ºC. Os ajustes (todos os R2s ≥ 0,70) ao modelo psi-graus-dia foram adequados para todas as cultivares, tanto na faixa supraótima quanto na infraótima. Assim sendo, ainda que mais estudos sejam necessários para melhorar a qualidade dos ajustes obtidos em relação... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Seed germination constitutes a crucial phase in relation to the life cycle of plant species. The composition of gases, temperature and water availability are the main environmental factors that may hinder several germination processes. Temperature and water availability, for example, are able to fluctuate considerably and may act as environmental "status' indicators to the seeds. The present work was aimed at furnishing a basic characterisation of the germination patterns of four Phaseolus vulgaris cultivars, viz. "Carioca comum', "Iapar 81", "IPR Graúna" and IPR Uirapuru; assessing the optimum range of germination for each cultivar; conducting experiments in which the effects of temperature and osmotic potential were simultaneously analysed in order to deploy mathematical models concerning the concept of degree-days (thermal time) with the aim of comparing the germination response of such cultivars. "IPR Graúna' exhibited a wider optimum range of temperature (nine distinct values) and "Iapar 81" presented only one temperature value as the optimum temperature (32.6ºC). The four cultivars did not germinate at temperatures higher than 38.2ºC and lower than 10.3ºC. The base temperatures derived from the application of the thermal time models varied from 8.4 to 9.2ºC. Regarding the hydrothermal-time model, the quality of the data fitting were deemed to be adequate (R2s ≥ 0.70) both in the suboptimum range and in the supra-optimum range. Other researches should be conducted in order to corroborate the present findings; nonetheless, the common bean cultivars were able to be compared and contrasted and exhibited, on the whole, a relatively homogenous... (Complete abstract click electronic access below) / Mestre

The recent emergence of highly virulent strains of the pathogen causing wheat stem rust has been acknowledged as a threat to global food security. In infected wheat fields, vast amounts of pathogenic fungal spores are produced that can be carried away by wind. For targeted disease surveillance and control it is important to estimate when, where and how many fungal spores are dispersed from infected to susceptible wheat fields. In this study, high-performance computational resources are used to investigate long-distance dispersal revealing atmospheric pathways that connect entire continents. Mechanistic simulations of turbulent atmospheric spore dispersal are conducted. The analyses bring together a variety of data, including international field disease surveys and finely resolved meteorological model data. The UK Met Office's Langrangian stochastic particle dispersion model, NAME, is applied, extended and coupled to other models in a set of case studies. In the first case study, spore dispersal is analysed across Southern/East Africa, the Middle East, and Central/South Asia by simulating billions of stochastic trajectories of fungal spores over dynamically changing host and environmental landscapes. The circumstances under which virulent strains, such as Ug99, pose a risk to globally important wheat producing areas are identified. Simulation results indicate a negligible risk for dispersal from key wheat producing countries on the East African continent (Ethiopia, Kenya) directly to India and Pakistan. However, there is a considerable risk for atmospheric transport from the Arabian Peninsula to South Asia. Spore dispersal trends are quantified between all countries in the domain providing estimates which can be used to improve targeted sampling and control. In the second case study, dispersal from southern Africa to Australia is analysed. Simulation results, as well as data from phenotypic and genotypic analyses, support the hypothesis that extremely long-distance airborne dispersal across the Indian Ocean is possible, albeit rare. This indicates that the pathogen populations on the two continents are connected and underlines the importance of sharing surveillance intelligence between continents. The third case study focusses on Ethiopia, determining likely origins of strain TKTTF that recently caused severe epidemics in East Africa's largest wheat producing country. The analyses suggest inflow into Ethiopia from the Middle East via Yemen, consistent with field survey data. The risk for inflow of pathogens into Ethiopia from key neighbouring countries is ranked for different months of the wheat season. In the last results chapter a pilot study is summarized testing the feasibility of an automated short-term forecasting system for spore dispersal from the latest field disease detection sites. Whilst the functionality and practical relevance of the forecasting system is demonstrated, considerable challenges remain for testing the forecasts. The predictive simulation framework described in this thesis can be applied to any wheat producing area worldwide to assess dispersal risks. The research has broader relevance because long-distance dispersal is a key mechanism for the transmission of several crop and livestock diseases, and also plays an important role in other areas of ecology.