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

Höhergradige Gliome gehören zu den häufigsten malignen Hirntumoren bei Erwachsenen und gehen mit einer sehr schlechten Prognose einher. Die Patientinnen und Patienten leiden häufig unter kognitiven Einschränkungen, welche auch auf einen Integritätsverlust der Weißen Substanz zurückzuführen sind und die Lebensqualität der Betroffenen stark beeinträchtigen. Um in Zukunft eine Behandlung zu gewährleisten, die nicht nur das Überleben verlängert, sondern auch den Erhalt der neurokognitiven Funktionen verbessert, sind zuverlässige Methoden zur Messung von Veränderungen der neurokognitiven Fähigkeiten in einem frühen Stadium erforderlich. Der direkteste Weg zur Objektivierung neurokognitiver Eigenschaften sind neuropsychologische Tests. Wir betrachten das Corpus callosum als eine zuverlässige Struktur zur Identifizierung der Verschlechterung der Integrität der weißen Substanz. Wir stellten die Hypothese auf, dass ein Zusammenhang zwischen einer beeinträchtigten strukturellen Integrität in bestimmten Regionen des Corpus Callosum und neurokognitiven Defiziten bei Patientinnen und Patienten mit höhergradigem Gliom besteht. Wir schlossen 25 Patientinnen und Patienten mit höhergradigem Gliom in unsere Studie ein, die sich präoperativ einer neuropsychologischen Testbatterie und einer MRT mit DTI Sequenzen unterzogen. Die MRT-Daten wurden mit der Software fsl, Oxford, verarbeitet. Neuropsychologische Parameter wurden mit der FA in drei Teilen des Corpus Callosum korreliert: Rostrum bzw. Genu, Truncus und Splenium. Präoperativ korrelierten die meisten neuropsychologischen Parameter signifikant mit der FA von mindestens einem Bereich des Corpus Callosum. Höhere FA-Werte wurden mit besserer Konzentration, Gedächtnis, Schnelligkeit und flüssigem Sprechen in Verbindung gebracht. Verschiedene Tests untersuchten den gleichen neuropsychologischen Parameter und korrelierten dann mit der gleichen Region des Corpus Callosum. So konnten das lexikalische und visuelle Gedächtnis mit dem Genu und Rostrum in Verbindung gebracht werden, exekutive Funktionen und das Arbeitsgedächtnis korrelierten mit dem Truncus und die Verarbeitungsgeschwindigkeit mit dem Splenium. Darüber hinaus stimmte diese Zuordnung mit den Ergebnissen vorangegangener Studien überein. Wir betrachten Veränderungen der mikrostrukturellen Integrität der Corpus Callosum als robustes morphologisches Korrelat für die Untersuchung des neurokognitiven Zustands von Patientinnen und Patienten mit höhergradigem Gliom. / High-grade gliomas are malignant brain tumors in adults and are associated with a very poor prognosis. Patients often suffer from cognitive impairment, which is due to a loss of integrity of the white matter and severely impairs the quality of life of those patients. To ensure a treatment that does not only lengthen survival, but also improves preservation of neurocognitive functions, reliable methods to measure changes in neurocognitive abilities at an early stage are necessary. The most direct way to objectify neurocognitive properties is neuropsychological testing. We take the corpus callosum as a reliable structure to identify decline of white matter integrity. We hypothesized a relation between compromised structural integrity in specific regions of the corpus callosum and neurocognitive deficits in glioma patients. We included 25 patients with high-grade glioma who underwent a neuropsychological test battery and MRI with Diffusion Tensor Imaging preoperatively. MRI data was processed using the software fsl, Oxford. Neuropsychological parameters were correlated with the Fractional Anisotropy (FA) in three parts of the corpus callosum: Rostrum or genu, truncus and splenium. Preoperatively most neuropsychological parameters correlated significantly with FA of at least one of the corpus callosum volumes. Higher FA-values were associated with better focus, memory, speed and fluency of speech. Different tests examined the same neuropsychological parameter and then correlated with the same region of the corpus callosum: Thus, lexical and visual memory could be linked to the genu and rostrum, executive functions and working memory correlated with the truncus and processing speed with the splenium. Furthermore, this correlation was consistent with the results of previous studies. We take changes of the microstructural integrity of corpus callosum as a robust morphological correlate for examination and progress monitoring of the neurocognitive state of glioma patients.

To test factors limiting regeneration of large-seeded hardwoods in the Upper Coastal Plain of South Carolina, we planted one-year old bare root Quercus alba L. and Cornus florida L. seedlings in pine plantation understories and adjacent clearcuts. We hypothesized that soil moisture, light, and leaf and stem herbivory would have relatively strong effects on growth and survival during the first two years after planting. Next to each seedling, we measured five abiotic factors (soil carbon and moisture, gap light index (GLI), and available nitrogen and phosphorus). We also estimated percent stem and leaf herbivory and harvested seedlings after the second year to measure seedling growth. Survival was not significantly different between clearcut (62.9%) and understory (64.6%) treatments. Biomass growth was significantly greater (P<0.05) in the clearcuts for both species. All abiotic variables measured except soil carbon were greater in the clearcuts (P<0.05). Each seedling growth response was regressed against all variables using forward selection (P=0.15). Soil moisture significantly affected survival in 12.5% and biomass growth in 16.7% of the regressions. Light availability significantly impacted biomass growth in 8.3% of the regressions. Neither leaf nor stem herbivory frequently affected survival, but one or the other or both significantly influenced the biomass growth of seedlings in 41.5% of the regressions. Herbivory had the strongest impact on seedling responses. Neither water nor light was very influential for growth or survival responses. We conclude that hardwood restoration in the uplands of the Upper Coastal Plain is best accomplished by planting in recent clearcuts. / Master of Science

(anglicky) Alba-family proteins were identified in Archaea and Eucarya and are classified among the oldest and the most conserved nucleic acid-binding proteins. The binding preferences and roles differ among certain evolution clades. In Crenarchaea they represent chromatin-binding proteins, while their role in RNA metabolism is suggested in Euryarchaea and Eukaryotes. ALBA proteins are well characterized in human, where they play a role in the RNAse P/MRP complex and in unicellular parasites, such as Plasmodium and Trypanosoma, where an involvement in the life cycle regulation is confirmed. In plants, their role is not yet well understood. The aim of this thesis is to increase a knowledge about the Alba-family proteins in the model plant Arabidopsis thaliana. Based on a minimal changes to development and reproduction in single mutants and high sequence similarity, a functional redundancy of the proteins was assumed. For better understanding of the ALBA proteins function, three smaller members of the family were edited by the same metod. The obtained triple mutant showed delay in flowering. ALBA dimer formation was confirmed in many organisms. BiFC method was used to determine Arabidopsis ALBA homodimerization. The data analysis showed potential homodimerization in most of them.

Aujourd’hui, en Amérique latine, il existe une véritable multiplication de l’activité multilatérale par la création de différents types d’espace de coopération : l’Union des Nations Sud-américaine (UNASUR), l’Alliance Bolivarienne Pour les Peuples de Notre Amérique (ALBA), l’Alliance du Pacifique et la Communauté des Etats Latino-américains et des Caraïbes (CELAC). Actuellement, pour définir ces nouvelles organisations multilatérales, les politiciens, les académiciens, les scientifiques et les juristes ont utilisé divers notions : processus d’intégration, intégration maximaliste, intégration politique, intégration énergétique, régionalisme post-néolibéral, nouveau régionalisme, nouveau processus d’intégration, convergence, coopération sociale, culturelle et économique, et instance de concertation du dialogue et de la politique. Pourtant l’intégration latino-américaine est une intégration discursive. Et parfois, elle est utilisée pour les processus de coopération.Cette nouvelle dynamique multilatérale latino-américaine entraine une problématique sur l’avenir et l’ampleur de la participation de l’Amérique latine, en tant que regroupement d’Etats, dans la nouvelle configuration de la gouvernance internationale. Ainsi, pour comprendre ces nouvelles formes de relations interétatiques, la construction et la consolidation de leurs niveaux d’institutionnalisation permettent d’obtenir des résultats sur le modèle de l’intégration et des relations multilatérales dans la région. / Today in Latin America, there is a real increase of multilateral activity through the creation of different types of cooperation areas, such as: the Union of South American Nations (UNASUR), the Bolivarian Alliance for the Peoples of the Americas (ALBA), the Pacific Alliance and the Community of Latin American and Caribbean States (CELAC).Currently, to define these new multilateral organizations, politicians, academia, scientists and lawyers, have used various definitions: the integration process, maximalist integration, political integration, energy integration, post-neoliberal regionalism, new regionalism, new process integration, convergence, social cooperation, cultural and economic and consultative body for dialogue and politics, among others. However, the integration of Latin America is a discursive interaction; and sometimes it is used for cooperation processes.This new Latin American multilateral dynamic leads to a problem for the future, to the extent of the participation of Latin America, as a grouping of states in the new configuration of international governance. Thus, in understanding the new forms of interstate relations, its construction and consolidation of its institutionalization stages, allowing for the model of the results of integration and multilateral relations in the region.

Les arbres ont la capacité de percevoir des sollicitations mécaniques quotidiennes dues au vent et d’acclimater leur croissance et leur développement en conséquence. Ce stress mécanique se traduit essentiellement par des flexions des organes, en particulier des branches et de la tige. Des études antérieures ont montré que la croissance en diamètre du peuplier était stimulée en réponse aux flexions mimant l’effet du vent. Cette augmentation de la croissance s’accompagne d’une modification de la nature du bois mis en place, qui a pu être observé chez quelques conifères et angiospermes, et nommé « bois de flexion ». Mais la caractérisation anatomique de ce bois a été peu approfondie, et les acteurs moléculaires de sa formation n’ont jamais été recherchés. De plus, dans la plupart de ces études les sollicitations mécaniques appliquées à la tige sont des flexions multidirectionnelles et d’intensité non contrôlée. Or, la déformation étant la variable physique perçue par la plante, il est nécessaire de contrôler l’amplitude de la flexion appliquée à la tige. Grâce à un dispositif expérimental original, nous avons appliqué des flexions unidirectionnelles sur de jeunes tiges de peupliers tout en contrôlant l’intensité des déformations appliquées. Cette étude a montré que la perception des déformations s’effectuait à une échelle locale, conduisant à une ovalisation de la tige. Nous avons pu également différencier le bois formé sous des déformations en tension, que nous avons nommé Tensile Flexure Wood, du bois formé sous des déformations en compression, que nous avons nommé Compressive Flexure Wood. Les analyses anatomiques et moléculaires montrent que l’intensité des déformations en valeur absolue ne suffit pas à expliquer toutes les réponses et que le signe (tension ou compression) de ces déformations joue également un rôle. Chez des arbres stimulés par des flexions unidirectionnelles plus fréquentes, la croissance et la différenciation cellulaire sont modulés encore différemment, notamment dans la zone en compression, apportant à la tige un bénéfice adaptatif face aux sollicitations suivantes. Le gène CLE12.2 appartenant à la famille des gènes CLAVATA, gènes impliqués dans les régulations méristématiques, a été montré mécanosensible. Une approche de génomique fonctionnelle du gène CLE12.2 par l’utilisation de plants transgéniques présentant une sous- ou une surexpression du gène nous a permis d’émettre l’hypothèse d’une implication du peptide CLE12.2 dans la régulation des voies de biosynthèse de la paroi cellulaire. Cette étude a permis de mettre en avant la complexité des mécanismes moléculaires impliqués dans la formation du bois et apporte de nouvelles connaissances pour la poursuite des études sur l’acclimatation des arbres au vent. / Trees have the ability to perceive daily mechanical stresses related to wind and to acclimate their growth and development accordingly. Wind essentially results in organs bending, in particular in branches and stem. Previous studies have shown that growth diameter of poplar stem increased in response to bending; mimicking wind mechanical effect. This growth increment goes along with a change in the structure of the wood formed under bending stimulation. This type of reaction wood has been described for some conifers and angiosperms species, and was called "flexure wood". Until now, its anatomical characteristics have been poorly described, and the molecular actors of its formation have never been investigated. In addition, in most of these previous studies the mechanical stresses applied to the stem were bidirectional bendings with an uncontrolled intensity. Because mechanical strains constitute the physical variable perceived by the plant, it appeared necessary to carefully control the bending amplitude applied to the stem. Thanks to an original experimental setup, we applied unidirectional bendings on young poplar stems, while controlling its intensity. This study showed that the strains are perceived at a local scale and that the secondary growth response was also local, leading to stem ovalization. We also distinguished the wood formed under tension we named “Tensile Flexure Wood” from the wood formed under compression we named “Compressive Flexure Wood”. The anatomical and molecular analyzes show that the strain intensity in absolute value is not enough to explain all the answers and that the sign (tension or compression) of these strains also plays a role. In trees stimulated by more frequent unidirectional bendings, growth and cell differentiation are modulated even differently, especially in the area under compression, bringing to the stem an adaptive benefit to the following solicitations. The CLE12.2 gene, which belongs to the CLAVATA gene family involved in meristematic regulation, has been shown to be mechanosensitive. Functional analysis of the CLE12.2 gene in transgenic plants with under- or overexpression of the gene allowed us to hypothesize that the CLE12.2 peptide is involved in the regulation of the cell-wall biosynthesis pathways. This work highlighted the complexity of the molecular mechanisms involved in wood formation and brings new knowledge for further studies on trees acclimation to wind.

Les hêtraies-sapinières-pessières de montagne paraissent particulièrement menacées par le réchauffement climatique. Pour appréhender la dynamique future de ces forêts et adapter la sylviculture à ces nouvelles conditions, il est important de mieux connaître les facteurs environnementaux impactant la démographie de ces espèces. Nous avons abordé cette problématique en combinant des données historiques de gestion, le modèle de dynamique forestière Samsara2 et une méthode de calibration basée sur le Calcul Bayésien Approché. Nous avons ainsi pu étudier conjointement les différents processus démographiques dans ces forêts. Nos analyses montrent que la démographie forestière peut varier fortement entre les parcelles et que le climat n'est pas toujours déterminant pour expliquer ces variations. Ainsi, malgré les changements climatiques attendus, la gestion irrégulière pratiquée actuellement devrait permettre de maintenir les services rendus par les peuplements mélangés situés en conditions mésiques. / The spruce-fir-beech mountain forests could be particularly threatened by the global warming. To better understand the future dynamics of these forests and adapt the silviculture to these new conditions, a better knowledge of the environmental factors affecting the species demograhics is needed. We studied this issue by combining a historical management data set, the forest dynamics model Samsara2 and a calibration method based on Approximate Bayesian Computation. We were able thus to study jointly the different demographic process in these forests. Our analysis show that the forest demographics can strongly vary between stands and that climate is not always determining to explain these variations. The unven-aged management currently applied seem adapted for the mixed stands located in mesic conditions, but the pure spruce forests and the low elevation stands could be highly impacted.

No description available.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esta dissertação avalia o impacto da política externa venezuelana na conformação de coesão social dentro dos países membros da Aliança Bolivariana para los Pueblos de Nuestra América (ALBA), especificamente Nicarágua, Bolívia e Equador, analisando aquelas políticas aplicadas durante o mandato do Presidente Hugo Chávez desde a criação do esquema de integração. Trabalha com a hipótese de que existe uma mudança dentro dos países da ALBA no que se refere à geração de coesão social a partir da aplicação de políticas externas que formam parte do chamado Socialismo do Século XXI. Este processo será analisado a partir de três pilares fundamentais da coesão social: distância, institucionalidade e senso de pertencimento, que se encontram dentro dos componentes estabelecidos pela Comissão Econômica para América Latina e o Caribe (CEPAL). / This thesis evaluates the impact of the Venezuelan foreign policy, towards the conformation of social cohesion inside member countries of the Aliança Bolivariana para los Pueblos de Nuestra América (ALBA), specifically the cases of Nicaragua, Ecuador and Bolivia. This analysis will be made using the policies applied during Chavez government, since the conformation of this integration initiative. The purpose of these work is to develop the hypotheses that a change has been made within the ALBA countries through the indicators of social cohesion as a consequence of Venezuelas foreign policies measures, part of the process denominate as XXI Century Socialism. The development of this process will be examined through three dimensions of the social cohesion defined by the Economic Commission for Latin America and the Caribbean (ECALC): distance, institucionality and sense of belonging.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Moraceae family consists of approximately 1000 species, distributed in 61 genera. Morus alba has small flowers, simple stems up to 33 feet tall and whole leaves, serrated or lobed, fruit September to November. M. alba is used in traditional medicine as hypoglycemic, antioxidant, anti-inflammatory and in the treatment of menopausal symptoms. Flavonoids such as quercetin, rutin and alkaloid 1- deoxinojirimicina were isolated and identified in their leaves. The physico-chemical quality control was performed with M. Alba s leaves collected in four seasons. The values found in the analysis of loss on drying and foreign matter are agreement with established for herbal drugs. The collection made in March had the highest content of total ash and acid insoluble and swelling index was higher in September. The dosages of polyphenols and flavonoids were higher in summer. The evaluation of anti-inflammatory activity of M. alba in induction of granulomatous tissue showed that animals treated with hydroethanolic extract presented 20.24 ± 6.94% inhibition of the formation of granulomatous tissue while those treated with nimesulide has 21.42 ± 6.52%, confirming significant anti-inflammatory activity. The dosages of AST, ALT and creatinine were performed with the same animals, demonstrating absence of toxicity in liver and kidney. In determining the in vitro antimicrobial activity, the fractions ethyl acetate and chloroform showed the best responses front of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus fumigatus, Prothoteca zophii and Candida albicans. The cytotoxicity of the hydroethanolic extract by cell cultures of Chinese hamster ovary (CHO) and cells of connective tissue of mouse (NCTC) clone 929 showed, respectively, IC50 of 0.34 mg/mL and 3.24 mg/mL. / A família Moraceae compreende aproximadamente 1000 espécies, distribuídas em 61 gêneros. Morus alba possui flores pequenas, caule simples com até 10 metros de altura e folhas inteiras, serreadas ou lobadas, frutifica de setembro a novembro. M. alba é utilizada na medicina tradicional como hipoglicemiante, antioxidante, anti-inflamatória e no tratamento dos sintomas da menopausa. Flavonóides como quercetina, rutina e o alcalóide 1-deoxinojirimicina foram isolados e identificados nas suas folhas. O controle de qualidade físico-químico foi realizado com folhas de M. alba coletadas nas quatro estações. Os valores encontrados nas análises de perda por dessecação e matéria estranha estão de acordo com os estabelecidos para drogas vegetais. A coleta realizada em março apresentou o maior conteúdo de cinzas totais e insolúveis em ácido e o índice de intumescência foi mais elevado em setembro. As dosagens de polifenóis e flavonóides foram mais elevadas no verão. A avaliação da atividade anti-inflamatória de M. alba em modelo de indução de tecido granulomatoso demonstrou que os animais tratados com o extrato hidroetanólico apresentaram 20,24 ± 6,94% de inibição da formação de tecido granulomatoso enquanto que os tratados com nimesulida apresentaram 21,42 ± 6,52%, confirmando significativa atividade anti-inflamatória. As dosagens de AST, ALT e creatinina foram realizadas com os mesmos animais, demonstrando ausência de indícios de toxicidade hepática e renal. Na determinação da atividade antimicrobiana in vitro, as frações acetato de etila e clorofórmio apresentaram as melhores atividades frente à Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus fumigatus, Prothoteca zophii e Candida albicans. A citotoxicidade do extrato hidroetanólico por culturas de células de ovário de hamster chinês (CHO) e células do tecido conectivo de camundongo (NCTC) clone 929 apresentaram, respectivamente, IC50 de 0,34 mg/mL e 3,24 mg/mL, demonstrando ação citotóxica in vitro.