Cette thèse porte sur les plongements d'espaces homogènes sphériques sur un corps quelconque. Dans une première partie, on aborde la classification de ces plongements, dans la lignée des travaux de Demazure et bien d'autres sur les variétés toriques, et de Luna, Vust et Knop sur les variétés sphériques. Dans une seconde partie, on généralise en caractéristique positive certains résultats obtenus par Bien et Brion portant sur les plongements complets et lisses qui sont log homogènes, c'est-à-dire dont le bord est un diviseur à croisements normaux et le fibré tangent logarithmique associé est engendré par ses sections globales. Dans une dernière partie, on construit par éclatements successifs une compactification lisse et log homogène explicite du groupe linéaire (différente de celle obtenue par Kausz). En prenant dans cette compactification les points fixes de certains automorphismes, on en déduit alors la construction de compactifications lisses et log homogènes de certains groupes semi-simples classiques. / This thesis is devoted to the study of embeddings of spherical homogeneous spaces over an arbitrary field. In the first part, we address the classification of such embeddings, in the spirit of Demazure and many others in the setting of toric varieties and of Luna, Vust and Knop in the setting of spherical varieties. In the second part, we generalize in positive characteristics some results obtained by Bien and Brion on those complete smooth embeddings that are log homogeneous, i.e., whose boundary is a normal crossing divisor and the associated logarithmic tangent bundle is generated by its global sections. In the last part, we construct an explicit smooth log homogeneous compactification of the general linear group by successive blow-ups (different from the one obtained by Kausz). By taking fixed points of certain automorphisms on this compactification, one gets smooth log homogeneous compactifications of some classical semi-simple groups.

O padrão espacial de espécies em florestas nativas pode fornecer evidências sobre a estrutura da comunidade vegetal. Fatores ambientais podem influenciar o padrão espacial das espécies, como as características edáficas e processos que dependem da densidade, como competição intra e interespecífica. Desse modo, a pesquisa da relação entre as características ambientais e o padrão espacial de espécies florestais pode ajudar a entender a dinâmica de florestas. O objetivo deste estudo foi empregar técnicas da análise de processos pontuais para verificar o efeito de fatores ambientais sobre a ocorrência de espécies florestais. A área de estudo foi a Estação Ecológica de Assis (EEA), da unidade de Conservação do Estado de São Paulo em parcelas permanentes, dentro do projeto \"Diversidade, dinâmica e conservação em florestas do Estado de São Paulo: 40 ha de parcelas permanentes\" do programa Biota da FAPESP. A descrição do padrão espacial das espécies mais abundantes na área de estudo foi avaliada pela função K proposta por Ripley e suas extensões para processo não homogêneos, por meio das coordenadas geográficas das espécies com circunferência na altura do peito igual ou superior a 15 cm. Modelos do Processo Poisson Homogêneo, Processo Poisson Não Homogêneos e do Processo Log Gaussiano de Cox foram ajustados para cada espécie. Foi utilizado o critério de AIC para selecionar o modelo que melhor se ajusta aos dados. Testes de diagnósticos dos modelos foram feitos utilizando a função K não homogênea sob a hipótese de Completa Aleatoriedade Espacial. Os resultados indicaram que as espécies mais abundantes na EEA apresentam um padrão de distribuição agregado, ou seja, o número esperado de indivíduos próximos de um evento qualquer é maior do que esperado para uma distribuição aleatória. Conforme esperado, os fatores ambientais desempenharam um importante papel para explicar a distribuição espacial das espécies, porém, os resultados indicaram que existe uma variação espacialmente estruturada que não foi incluída na análise que é imprescindível para um bom ajuste dos modelos. Portanto os resultados sugerem que outros fatores não incluídos nos modelos e dados disponíveis podem estar determinando os padrões espaciais além das (co)variáveis medidas. / The spatial pattern of species in native forests may provide evidence on the structure of the plant community. Environmental factors may influence the species\' spatial patterns, as well as soil characteristics and processes which depend on the density, as intraspecific and interspecific competition. Therefore, researching the relationship among the environmental features and the spatial pattern of the forest species may aid in understanding forest dynamics. The goal of this study was to apply point process techniques to verify the effect of environmental factors on the occurence of forest species. The study area was the \"Assis\'s Ecological Station\" (AES), of the \"Unit of conservation of the state of São Paulo in permanent plots\". The data was collected as part of the project entitled \"Diversity, dynamics and conservation in forests of São Paulo state: 40 ha of permanent plots\", from FAPESP\'s Biota program. The description of the spatial pattern of the most abundant species in the study area was assessed using Ripley\'s K function, using the species\' geographic coordinates with circumference at chest height equal or larger than 15 cm. Homogeneous and Non-Homogeneous Poisson Process models, as well as Cox Log Gaussian Process models were fitted to each species. Model selection was made using the Akaike information criterion. Diagnostics tests were made using the non-homogeneous K function under the hypothesis of complete spatial randomness. Results suggested that the most abundant species in the AES present an aggregate distribution pattern, i.e., the expected number of individuals next to any event is larger than the expected by a random distribution. As it was expected, environmental factors played a major role in explaining the spatial distribution of the species. However, results suggested that there is a spatially structured variation that was not included in the analysis and is needed to a good model fit. Therefore, further studies are needed to assess which environmental feature which was not considered in this study presents an effect on the occurence of these forest species

The aim of this thesis is to examine women's educational attainment and social mobility in contemporary South Korea. This study seeks to answer to the following key research questions: 1) how much parents' characteristics such as occupational status and educational attainment, are important to their children's education and class; 2) the roles of educational qualification to occupational attainment in contemporary South Korea; 3) whether South Korea has become a more equal society with improved mobility chances for people of different social origins; and, 4) if there is a general pattern of social mobility and social fluidity in South Korea, how it is related to the change in the occupational positions of women. This research uses the Korean Labour and Income Panel Study (KLIPS) from 1998 to look at the changing relationship between social origin, education, and destination and what it indicates the role of education in the social mobility in Korea. The following tools are used for the analysis: I adopt Goldthorpe's class schema and CASMIN scales of educational qualifications. I then separately look at the association for men and women separately. Various statistical methods are subsequently employed to explore the substantive research questions: I use descriptive analysis for changes of Korea's educational attainment and look at absolute rates of mobility. Disparity ratios and odds ratios are used for describing the relative patterns and chances of educational attainment and mobility and regression model are used for analysing the impact of a range of factors on educational attainment and class destination. Finally, I draw on log-linear and log-multiplicative analysis for the trends in relative mobility and social fluidity. I find that access to education is still influenced by social background. Although the disparities between men and women become narrower across cohort, class and gender differentials in general educational attainment still apply to South Korea. Regarding the relative mobility rates, the results from disparity ratios show that the social class and gender differentials in class mobility still exist and the results of odds ratios confirm that social origin has a significant effect on children's social class destination. Looking at the origin-education (OE) association, class differences are still considerable and the relationship between class origins and educational attainment remains. Turning to the association between educational attainment and occupational destination (ED), qualifications continue to play a critical role in entry into the labour market remains, but there is no evidence that the association between education and destination has strengthened over time. Looking at the direct association between origins and destination (OD), the evidence shows the continuing association of origins on destinations. Regression analysis shows that the origin class effects upon educational attainment and occupational destinations were not dramatically decreased, but there were significant changes for women but not for men. The findings from the log-linear and log-multiplicative analysis suggest that there is trendless fluctuation and a stronger link between education and destination for women than for men.

La présente thèse vise à explorer différents types de modèles log-bilinéaires dans le domaine des sciences actuarielles. Le point de départ consiste en le modèle de Lee-Carter, utilisé pour les problèmes de projection de la mortalité. Différentes variantes sont développées, et notamment le modèle de Poisson log-bilinéaire. L'introduction de variables explicatives est également analysée. Enfin, une tentative de d'exportation de ces modèles au cas des triangles IBNR est effectuée.

La présente thèse vise à explorer différents types de modèles log-bilinéaires dans le domaine des sciences actuarielles. Le point de départ consiste en le modèle de Lee-Carter, utilisé pour les problèmes de projection de la mortalité. Différentes variantes sont développées, et notamment le modèle de Poisson log-bilinéaire. L'introduction de variables explicatives est également analysée. Enfin, une tentative de d'exportation de ces modèles au cas des triangles IBNR est effectuée.

Wenn sich Bibliotheksmitarbeiterin und Bibliotheksnutzer nicht von Angesicht zu Angesicht gegenüber stehen, ist diese Frage berechtigt: Sind Sie ein Mensch? Oder sind Sie ein automatisierter Chatroboter – vergleichbar mit telefonischen Informationshotlines, die wohl jeder aus leidvoller Erfahrung kennt? Gestellt wurde uns diese Frage tatsächlich – und mehrfach – von Bibliotheksnutzerinnen und -nutzern, die ihr Glück kaum fassen konnten, wie einfach es sein kann, eine Antwort direkt online zu bekommen. Es muss nicht immer die Auskunftstheke sein. Virtuell hilft auch!

Dans l'analyse d'images médicales, les déformations géométriques sont utilisées pour modéliser la variabilité entre les patients. Dans les applications orthopédiques, la variabilité géométrique est habituellement observable à différentes échelles. Dans le cas des os mandibulaires, par exemple, on observe des différences anatomiques entre le côté gauche et droit sur une échelle grossière, ou entre les dents sur une échelle plus fine. Chaque niveau de granularité contient des régions d'intérêt pour les applications cliniques. La difficulté est de relier les déformations géométriques avec les régions d'intérêt pour chaque type d'échelles. Dans cette thèse, nous présentons cette liaison par l'introduction du recalage difféomorphe et structuré. Le coeur de notre méthode est le paramétrage des déformations géométriques avec des arbres de transformations localement affines qui décrivent la variabilité entre les patients. En second lieu, nous modélisons statistiquement les paramètres de déformations dans une population par la formulation d'un modèle statistique génératif. Cette méthode nous permet d'intégrer des statistiques de déformations comme une probabilité a priori dans un cadre Bayésien et elle nous permet d'étendre le recalage classique d'un schéma grossier à un schéma fin avec une optimisation simultanée pour toutes les échelles. Nous validons notre approche sur plusieurs applications orthopédiques: la conception des implants pour une population, des simulations biomécaniques et la sélection d'allogreffes. L'amélioration de l'intelligibilité pour les cliniciens et de la précision obtenue fait de notre méthode un candidat prometteur pour des usages cliniques.

Es wird eine Bioassay-Analyse von 168 Testsubstanzen gegenüber Tetrahymena pyriformis beschrieben. Mithilfe dieses In-vitro-Ansatzes konnte eine erste prognostische Aussage über die toxische Wirkung unbekannter Stoffe getroffen werden. Aus den Konzentrations-Wirkungs-Beziehungen erfolgte eine Bestimmung der Toxizitätserhöhung gegenüber der Narkoselevel-Toxizität. Dadurch war eine mechanistische Interpretation der Wirkstärke der Fremdstoffe möglich. Die Wirkung der Fremdstoffe basiert auf direkten toxikologisch relevanten Reaktionsmechanismen mit nukleophilen Biomolekülen oder nach entsprechender enzymatischer Aktivierung und ermöglichte die Aufstellung von Strukturalarmen. Aus jeder Stoffklasse waren Vertreter direkt oder nach enzymatischer Biotransformation erhöht toxisch. Somit ist mithilfe der Ciliaten eine Vorhersage der direkten reaktiven Toxizität möglich. Zudem enthält es für eine metabolische Aktivierung bedeutsame Enzymsysteme. Damit ist es für eine prognostische Vorhersage der Toxizität unbekannter Stoffe anwendbar.

Despite the Family Code of 2000 that raised the legal age at marriage to 18 for both sexes; early family formation is still a common practice which affect many children in Ethiopia. Previous research has shown that girls in rural areas are more disadvantaged and suffer the consequences of early marriage the most. The purpose of this thesis is to study the risk factors for early marriage for both girls and boys in an urban area, Shashemene. Also, using longitudinal data, trends in early family formation between 1973 and 2008 have been analyzed with an event history approach. The data were collected as part of the project “Changing Ethiopia: Urban livelihood, gender, and ethnicity in Shashemene after 35 years: A case study”. The discrete-time complementary log-log regression estimates have provided evidence of gender inequality in early marriage formations, showing that girls are more prone to experience early marriage than boys. While area of birth (rural-urban) has no direct impact on the risk of early marriage, it is found that living in an urban area offsets the effect of area of birth, suggesting a selection process into migration. It is also found that school attendance decreases the likelihood of early marriage, while literacy has little effect. Moreover, among people living in Shashemene, religious affiliation has more impact on early marriage risks than ethnic identity and the first language. Finally, there was little evidence on period and cohort effects for early family formation.

Made available in DSpace on 2015-03-26T13:32:15Z (GMT). No. of bitstreams: 1 texto completo.pdf: 512216 bytes, checksum: fd4223913c0ad60bce75a563695255ec (MD5) Previous issue date: 2012-03-13 / In survival analysis, the response variable is the time of occurrence of an event of interest, denominated failure time. Another characteristic of the survival analysis is to incorporate to the study incomplete sample data, in which for a determined reason the occurrence of the event was not verified, being these data defined as censured. The objective of this paper was to compare the use of the parametric and non-parametric techniques to estimate the survival time of C. externa (Neuroptera: Chrysopidae), predator insect which feed on other insects as well as mite, under the effect of three commercial products nim-based: Neempro (10 g of azadirachtina L-1), Organic neem (3,3 g of Azadirachtina L-1) and Natuneem (1,5 g of azadirachtina L-1). With this objective the survival functions for the different concentrations of each product, through the non-parametric method of Kaplan-Meier were estimated and compared by the logrank test and by parametric techniques, using the Weibull and log-normal exponential tests. Besides that, a study in order to select the most parsimonious model was done, using for that the likelihood ratio test (LRT) as well as the Akaike information criterion (AIC). The estimates of the selected parametric model were used to determine the survival functions in the concentrations of the three products, with the purpose of comparing with the nonparametric estimator Kaplan-Meier. Once the best model was defined the median survival time of C. externa was calculated in the tested concentrations of the products. Taking into consideration the conditions described in this experiment, one can conclude that the concentrations of the nim-based products have influence in the survival of C. externa. The higher the concentration of the used products, the lower was the survival time and among the evaluated products, Neempro was the one which presented the least lethal to the natural predator. / Em análise de sobrevivência, a variável resposta é o tempo de ocorrência de um evento de interesse, denominado tempo de falha. Outra característica da análise de sobrevivência é incorporar ao estudo dados amostrais incompletos, que por algum motivo a ocorrência do evento não foi verificada, dados estes definidos como censurados. O objetivo deste trabalho foi comparar o uso das técnicas paramétricas e não-paramétricas para estimar o tempo de sobrevivência de C. externa (Neuroptera: Chrysopidae), inseto predador que se alimenta de outros insetos e ácaros, sob efeito de três produtos comerciais à base de nim: Neempro (10 g de azadirachtina L-1), Organic neem (3,3 g de Azadirachtina L-1) e Natuneem (1,5 g de azadiractina L-1). Com esse objetivo foram estimadas as funções de sobrevivência para as diferentes concentrações de cada produto, por meio do método não-paramétrico de Kaplan-Meier, e comparadas pelo teste logrank e por meio das técnicas paramétricas, utilizando os modelos exponencial, de Weibull e log-normal. Foi realizado ainda, um estudo com a finalidade de selecionar o modelo mais parcimonioso, utilizando para isto o teste da razão de verossimilhança (TRV) e o critério de informação de Akaike (AIC). As estimativas do modelo paramétrico selecionado foram usadas para determinar as funções de sobrevivência nas concentrações dos três produtos, com o objetivo de comparar com o estimador não-paramétrico de Kaplan-Meier. Definido o melhor modelo foi calculado o tempo mediano de sobrevivência do C. externa nas concentrações testadas dos produtos. Levando em consideração as condições descritas neste experimento, pode-se concluir que as concentrações dos produtos a base de nim possuem influencia na sobrevivência de C. externa. Quanto maior foi a concentração dos produtos utilizados, menor foi o tempo de sobrevivência e entre os produtos avaliados o Neempro foi o que apresentou ser o menos letal ao predador natural.