Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

A nova is a cataclysmic variable star consisting of a white dwarf and a main sequence, subgiant or red giant companion. In a nova explosion, the white dwarf undergoes a thermonuclear runaway on its surface, as a result of build-up of accreted material from its companion. This leads to a large expulsion of matter from the WD surface, as well as a dramatic increase in the optical magnitude of the system. In this thesis, 5GHz C-band e-MERLIN observations of two novae (V959 Mon and V339 Del) and one symbiotic star (AG Pegasi) are presented. V959 Mon is a classical nova which was discovered in June 2012 by the Fermi Large Area Telescope as a gamma-ray source. High resolution e-MERLIN images of V959 Mon were made at six epochs following the June 2012 outburst, between 90 and 615 days after the Fermi discovery. The first four e-MERLIN observations revealed a morphology which was aspherical and expanding in the east-west direction. However, in the last two epochs, V959 Mon's ejecta morphology changed from being elongated east-west to being elongated north-south. Constant velocity models fit to measurements of V959 Mon's angular size at each epoch indicated that the expansion rate of the north-south component was significantly slower than that of the east-west component. The e-MERLIN observations of V339 Del and AG Pegasi were not as well resolved as the observations of V959 Mon, and only limited analysis of their ejecta structure was possible. In order to understand the complicated morphology seen in the e-MERLIN observations of V959 Mon, radio emission models of nova ejecta were constructed, and e-MERLIN observations of them were simulated. When constructing the models, two possible explanations for V959 Mon's morphology were explored. Firstly, the possibility was considered that the elongation observed in V959 Mon's ejecta, which changed over time from east- west to north-south, was spurious, resulting from incomplete sampling of the uv plane by e-MERLIN. To investigate this, an expanding spherical shell of ejecta was simulated, the extent to which its shape was distorted in simulated e-MERLIN images of it was investigated. Secondly, emission from an ejecta model featuring two components - one fast-moving component in the east-west direction, and another, more slow-moving component in the north-south direction - was simulated, in order to determine whether such an ejecta structure could result in the morphology seen in the e-MERLIN observations of V959 Mon. It was found that the spherical, Hubble flow model simulations were a reasonably good fit to V959 Mon's light curve, but could not explain the east-west elongation seen in V959 Mon's ejecta at the early epochs. Simulated observations of the two-component model were morphologically similar to V959 Mon, but produced light curves which were much fainter than V959 Mon's, indicating that a more in-depth analysis of two-component models of nova ejecta is necessary.

The ability to spatially restrict specific activities across the cell cortex functionally defines individual cells and tissues. This is achieved, in part, via the assembly of protein complexes that link the plasma membrane to the underlying cortical actin cytoskeleton. The neurofibromatosis type 2 (NF2) tumor suppressor Merlin and closely related ERM proteins (Ezrin, Radixin and Moesin) are a special class of such membrane:cytoskeleton associated proteins that function to organize specialized cortical domains. In addition to their high degree of similarity, mounting evidence suggests that Merlin/ERMs share a functional relationship, which is largely unexplored. Unlike Merlin, the ERMs are not known to inhibit cell proliferation; in fact, Ezrin is thought to promote tumor metastasis. Defining the relationship between Merlin and the ERMs is essential to appreciating their respective roles in cancer development. Here I demonstrate a novel role for Merlin and the ERMs in generating cortical asymmetry in the absence of external cues. Our data reveal that Merlin functions to restrict the cortical distribution of Ezrin, which in turn positions the interphase centrosome in single epithelial cells and 3D organotypic cultures. In the absence of Merlin, ectopic cortical Ezrin yields mispositioned centrosomes, misoriented spindles and aberrant epithelial architecture. Furthermore, in tumor cells with centrosome amplification, the failure to restrict cortical Ezrin abolishes centrosome clustering, yielding multipolar mitoses. Consistent with a functional relationship, I observe a strong genetic interaction between Nf2 and Ezrin in the mouse intestine in vivo. Finally, I begin to address the basis of their functional interaction by testing whether they are coordinately regulated by the Ste-20 like kinase SLK. Altogether, these data uncover fundamental roles for Merlin/ERM proteins in spatiotemporally organizing the cell cortex in vitro and in vivo and suggest that Merlin’s role in promoting cortical heterogeneity may contribute to tumorigenesis by disrupting cell polarity, spindle orientation and potentially genome stability.

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La prolifération cellulaire et la croissance tissulaire sont étroitement contrôlées au cours du développement. Chez la Drosophila melanogaster, ces processus sont régulés en partie par la kinase stérile-20 Slik (SLK et LOK chez les mammifères) et le suppresseur de tumeur Hippo (Hpo, MST1/2 chez les mammifères) dans les cellules épithéliales. La surexpression de la kinase Slik augmente la taille des tissus chez les mouches adultes. Cependant, les mutants slik-/- meurent avant d'avoir terminé leur développement. Lorsqu’elle est surexprimée dans les cellules épithéliales des ailes en voie de développement, cette protéine favorise la prolifération cellulaire. En outre, l'expression de Slik dans une population de cellules conduit à une surprolifération des cellules voisines, même quand elles sont physiquement séparées. Ceci est probablement dû à la sécrétion de facteurs de croissance qui stimulent la prolifération de manière paracrine. En utilisant des méthodes génétiques et transcriptomiques, nous essayons de déterminer les molécules et les mécanismes impliqués. Contrairement à ce qui a été publié, nous avons constaté que Slik ne transmet pas de signal prolifératif en inhibant le suppresseur de tumeur Merlin (Mer, NF2 chez les mammifères), un composant en amont de la voie Hippo. Plutôt, elle favorise la prolifération non-autonome et la croissance des tissus en signalisation par la kinase dRaf (la seule kinase de la famille Raf chez la drosophile). Nous prouvons que dRaf est nécessaire chez les cellules voisines pour conduire la prolifération chez ces cellules. De plus, nous avons utilisé le séquençage du transcriptome pour identifier de nouveaux effecteurs en aval de Slik. Ce qui permettra de mieux comprendre les effets de SLK et LOK chez les humains. / Cell proliferation and tissue growth are tightly controlled during development. In epithelial tissues in Drosophila melanogaster, these processes are regulated in part by the Sterile-20 kinase Slik (SLK and LOK in mammals) and the tumor suppressor Hippo (Hpo, MST1/2 in mammals). Slik overexpression leads to an increase in tissue size in flies, whereas, slik-/- mutants die before completing development. Overexpressing this protein in the developing wing disc epithelium promotes cell proliferation, consistent with the overgrown wing phenotype in the adults. Moreover, expression of Slik in one population of cells leads to an overproliferation of neighboring cells, even when they are physically separated by a central lumen. This can be explained by secretion of paracrine growth factors, stimulating non-autonomous proliferation that is specific to Slik. We used genetic and transcriptomic assays to define the molecules and mechanism involved in Slik-mediated signaling. Contrary to what has been suggested, we found that Slik does not promote proliferation through the tumor suppressor Merlin (Mer, NF2 in mammals), an upstream component of the Hippo pathway, nor through other components of the Hippo pathway. Rather, Slik promotes non-autonomous proliferation and tissue growth signaling through dRaf (the single Raf family kinase orthologue in Drosophila). We found that dRaf is required in the signal receiving cells to stimulate proliferation. We performed RNA-seq to identify novel downstream effectors of Slik. Characterizing the signaling pathway downstream of Slik in Drosophila will shed light on how SLK and LOK function in mammals, and provide insights into their potential involvement during development and in cancer.

A geração automatizada de Interfaces de Usuário (IU) é objeto de estudo há muitos anos. Desde a década de 80, dezenas de projetos foram desenvolvidos e várias soluções apresentadas ao mercado. Entretanto, mesmo com os avanços obtidos neste cenário, inúmeras dificuldades ainda continuam presentes no dia-a-dia dos desenvolvedores de sistemas. A necessidade de processos, sintaxes e linguagens proprietárias associado ao elevado esforço de configuração e à baixa reutilização de tecnologias são os principais problemas nessa área. Objetivando sanar essas dificuldades, este trabalho propõe uma solução diferenciada para o problema, a qual reutiliza e integra-se à maioria das tecnologias comumente presentes nos ambientes de desenvolvimento e que conta com um exclusivo sistema de configuração, capaz de minimizar o trabalho de geração das IU. Sendo um típico gerador baseado em modelos, o software proposto é chamado MERLIN, e objetiva automatizar completamente a geracão de interfaces CRUD, as quais estão presentes em até 30% dos sistemas que operam sobre banco de dados. Para alcançar este objetivo, o software aposta no uso intensivo de heurísticas e na formação de uma estrutura auto-contida e realimentada de configurações, a qual reside unicamente nas classes compiladas da aplicação. Completando a sua arquitetura, um processo de geração em tempo de execução inibe a produção de qualquer linha de código-fonte, o que evita a necessidade de refatoração ao longo da evolução dos sistemas. Com esses elementos em evidência e focando inicialmente a plataforma Java, sinaliza-se uma solução diferenciada, apta para ser utilizada em ambientes profissionais de desenvolvimento. / The automated generation of User Interfaces (UI) has been the object of study for many years. Since the 1980s, dozens of projects have been developed and various solutions presented to the market. However, even with the advances obtained under this scenario, innumerable difficulties still continue to present themselves in the daily routine of system developers. The demands of proprietary methodologies, syntaxes and languages, the high level of effort needed for configuration and low reuse of technologies are the main problems in the area. With the object of rectifying these difficulties, this work proposes a solution specific to the problem, which reuses and combines the majority of the technologies already existing in development environments and relies on an exclusive configuration system, capable to minimize the work of generating the UI. Being a typical model based generator, the software under consideration is called MERLIN, and has as its objective to completely automate the generation of CRUD interfaces, which are present in up to 30% of the systems that interact with data bases. To achieve this objective, the software relies on the intensive use of heuristics and the creation of a self contained configuration feedback structure, which exists solely in the compiled classes of the application. Completing this architecture, a process of execution time generation eliminates the need for any source code, which significantly reduces the costs of refactoring the code throughout the evolution of the systems. With these elements in evidence and focusing initially on the Java platform, indicates that this distinguished solution is ready for use in professional development environments.

A geração automatizada de Interfaces de Usuário (IU) é objeto de estudo há muitos anos. Desde a década de 80, dezenas de projetos foram desenvolvidos e várias soluções apresentadas ao mercado. Entretanto, mesmo com os avanços obtidos neste cenário, inúmeras dificuldades ainda continuam presentes no dia-a-dia dos desenvolvedores de sistemas. A necessidade de processos, sintaxes e linguagens proprietárias associado ao elevado esforço de configuração e à baixa reutilização de tecnologias são os principais problemas nessa área. Objetivando sanar essas dificuldades, este trabalho propõe uma solução diferenciada para o problema, a qual reutiliza e integra-se à maioria das tecnologias comumente presentes nos ambientes de desenvolvimento e que conta com um exclusivo sistema de configuração, capaz de minimizar o trabalho de geração das IU. Sendo um típico gerador baseado em modelos, o software proposto é chamado MERLIN, e objetiva automatizar completamente a geracão de interfaces CRUD, as quais estão presentes em até 30% dos sistemas que operam sobre banco de dados. Para alcançar este objetivo, o software aposta no uso intensivo de heurísticas e na formação de uma estrutura auto-contida e realimentada de configurações, a qual reside unicamente nas classes compiladas da aplicação. Completando a sua arquitetura, um processo de geração em tempo de execução inibe a produção de qualquer linha de código-fonte, o que evita a necessidade de refatoração ao longo da evolução dos sistemas. Com esses elementos em evidência e focando inicialmente a plataforma Java, sinaliza-se uma solução diferenciada, apta para ser utilizada em ambientes profissionais de desenvolvimento. / The automated generation of User Interfaces (UI) has been the object of study for many years. Since the 1980s, dozens of projects have been developed and various solutions presented to the market. However, even with the advances obtained under this scenario, innumerable difficulties still continue to present themselves in the daily routine of system developers. The demands of proprietary methodologies, syntaxes and languages, the high level of effort needed for configuration and low reuse of technologies are the main problems in the area. With the object of rectifying these difficulties, this work proposes a solution specific to the problem, which reuses and combines the majority of the technologies already existing in development environments and relies on an exclusive configuration system, capable to minimize the work of generating the UI. Being a typical model based generator, the software under consideration is called MERLIN, and has as its objective to completely automate the generation of CRUD interfaces, which are present in up to 30% of the systems that interact with data bases. To achieve this objective, the software relies on the intensive use of heuristics and the creation of a self contained configuration feedback structure, which exists solely in the compiled classes of the application. Completing this architecture, a process of execution time generation eliminates the need for any source code, which significantly reduces the costs of refactoring the code throughout the evolution of the systems. With these elements in evidence and focusing initially on the Java platform, indicates that this distinguished solution is ready for use in professional development environments.

The Great Observatories Origins Deep Survey North (GOODS-N) field, first surveyed by the HST, has been observed across numerous wavebands revealing populations of both Star Forming Galaxies (SFG) and Active Galactic Nuclei (AGN) over wide ranges of luminosities. It has been surmised that the evolution in the star forming population appears to diverge from that in the AGN population leading to a domination of SFGs at low flux densities. The number of starbursts can only be disentangled from the entire population if each source can be classified individually, which usually requires high angular resolution imaging. This is the motivation behind the e-MERLIN Galaxy Evolution survey, e-MERGE, which expands the depth of high resolution radio imaging in the GOODS-N field to increase the number of potentially classifiable sources. By use of wide-field imaging techniques, including a new high-speed mapping tool, together with a new semi-empirical primary beam-shape model for the e-MERLIN array, a deep wide-field high-resolution map is derived. This is the widest and deepest contiguous imaging yet obtained from e-MERLIN and JVLA observations, and yet contains less than 25% of the e-MERLIN data so far observed. The majority of the objects are shown to exhibit extended structure, and the angular size distribution place the median size around 1.2 arcsec, peaking between 0.5 and 0.7 arcsec. Automated algorithms are utilised to facilitate a new probabilistic classification tool based on multi-parameter correlations. 248 sources could be classified using the tool, each deriving a probability of AGN or SFG rather than forcing a binary category. Linear sizes of star-formation dominated sources are determined to lie in a range of 4 - 11 kpc, within the optical extent of galaxies. Differential source counting based on probabilistic classifications reveals that an increase in the luminosity evolution of SFGs is likely, although an apparent upturn in AGN may also exist to some lesser degree at low flux densities. The thesis establishes a clear roadmap for the remainder of the e-MERGE survey and a path to determine the star formation rate history of the Universe.

A geração automatizada de Interfaces de Usuário (IU) é objeto de estudo há muitos anos. Desde a década de 80, dezenas de projetos foram desenvolvidos e várias soluções apresentadas ao mercado. Entretanto, mesmo com os avanços obtidos neste cenário, inúmeras dificuldades ainda continuam presentes no dia-a-dia dos desenvolvedores de sistemas. A necessidade de processos, sintaxes e linguagens proprietárias associado ao elevado esforço de configuração e à baixa reutilização de tecnologias são os principais problemas nessa área. Objetivando sanar essas dificuldades, este trabalho propõe uma solução diferenciada para o problema, a qual reutiliza e integra-se à maioria das tecnologias comumente presentes nos ambientes de desenvolvimento e que conta com um exclusivo sistema de configuração, capaz de minimizar o trabalho de geração das IU. Sendo um típico gerador baseado em modelos, o software proposto é chamado MERLIN, e objetiva automatizar completamente a geracão de interfaces CRUD, as quais estão presentes em até 30% dos sistemas que operam sobre banco de dados. Para alcançar este objetivo, o software aposta no uso intensivo de heurísticas e na formação de uma estrutura auto-contida e realimentada de configurações, a qual reside unicamente nas classes compiladas da aplicação. Completando a sua arquitetura, um processo de geração em tempo de execução inibe a produção de qualquer linha de código-fonte, o que evita a necessidade de refatoração ao longo da evolução dos sistemas. Com esses elementos em evidência e focando inicialmente a plataforma Java, sinaliza-se uma solução diferenciada, apta para ser utilizada em ambientes profissionais de desenvolvimento. / The automated generation of User Interfaces (UI) has been the object of study for many years. Since the 1980s, dozens of projects have been developed and various solutions presented to the market. However, even with the advances obtained under this scenario, innumerable difficulties still continue to present themselves in the daily routine of system developers. The demands of proprietary methodologies, syntaxes and languages, the high level of effort needed for configuration and low reuse of technologies are the main problems in the area. With the object of rectifying these difficulties, this work proposes a solution specific to the problem, which reuses and combines the majority of the technologies already existing in development environments and relies on an exclusive configuration system, capable to minimize the work of generating the UI. Being a typical model based generator, the software under consideration is called MERLIN, and has as its objective to completely automate the generation of CRUD interfaces, which are present in up to 30% of the systems that interact with data bases. To achieve this objective, the software relies on the intensive use of heuristics and the creation of a self contained configuration feedback structure, which exists solely in the compiled classes of the application. Completing this architecture, a process of execution time generation eliminates the need for any source code, which significantly reduces the costs of refactoring the code throughout the evolution of the systems. With these elements in evidence and focusing initially on the Java platform, indicates that this distinguished solution is ready for use in professional development environments.