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"Ce Mémoire présente les études que nous avons effectué sur la nature d’organosilanes adsorbés sur le mica. Nous avons d’abord cherché à déterminer par quel processus les organosilanes établissent des liaisons covalentes avec le mica qui ne possède pas intrinsèquement à sa surface les groupements hydroxyle nécessaires. Ainsi, nous avons observé que le mica adsorbe, dans le milieu réactionnel aqueux, des ions hydronium (ou hydrogène) en libérant des ions potassium. Nous croyons que l’adsorption de ces ions peut entraîner la création de groupements hydroxyle intermédiaires qui peuvent, par la suite, réagir avec les silanes. Ce caractère basique du mica est une des causes de l’orientation normale des molécules de silane à sa surface. Le mica n’adsorbe pas les organosilanes de la même façon que le gel de silice Cab-O-Sil qui a une surface hydroxylée. Ce dernier n’adsorbe qu’une monocouche de silane qui est fortement retenue à la surface, et les molécules y sont dans une position parallèle. Nous attribuons cette différence de comportement entre le mica et le Cab-O-Sil au caractère acido-basique propre à chacune des deux surfaces; le mica a plus d’affinité avec les groupements silanol des organosilanes que le Cab-O-Sil qui a, de son côté, plus d’affinité avec les groupements ammonium. Nous avons aussi cherché à déterminer la structure des différentes monocouches des silane adsorbées sur le mica. A cause de la nature floconneuse des échantillons, la spectroscopie infrarouge à transformée de Fourier en transmission, en réflexion totale atténuée et en réflectance diffuse s’est avérée peu efficace. Pour sa part, la spectroscopie ESCA a permis de démontrer que les aminosilanes adsorbés sur le mica possèdent des groupements amine libres et protonés. La variation dans la proportion relative de ces deux types de groupements entraîne probablement une variation de l’énergie de surface du mica recouvert de silane. D’un autre côté, la spectroscopie ESCA n ’a permis de détecter qu’une seule monocouche de silane. Nous avons conséquemment émis l’hypothèse qu’une certaine quantité de silane peut être adsorbée à l’intérieur des cristaux de mica. Enfin, nous avons remis en question le modèle de Favis et coll. (J. Appl. Polym. Sc., 28, 1235, 1983) concernant l’orientation des mono­ couches d’organosilanes sur le mica. En effet, ces auteurs ont proposé que les molécules de monocouches successives ont des orientations opposées; par exemple, selon ce modèle, la deuxième monocouche du silane CVBS doit présenter une surface hydrophile composée de groupements silanol. Or, nous avons observé que cette deuxième monocouche est hydrophobe, ce qui est en contradiction avec les prédictions du modèle. Nous attribuons alors la variation, observée par Velazquez (Thèse de maîtrise, Université Laval, 1985), de l’énergie de surface avec le nombre de monocouches de silane adsorbé sur le mica à une variation de la quantité de groupements amine et ammonium, telle qu’observée en spectroscopie ESCA." / Québec Université Laval, Bibliothèque 2018

Made available in DSpace on 2015-04-14T13:55:18Z (GMT). No. of bitstreams: 1 446755.pdf: 2006363 bytes, checksum: 40b9e3405da029b723f7539f10ace148 (MD5) Previous issue date: 2013-03-27 / The last decades of the twentieth century and early twenty first century establish the threshold for a change of scene in the international relations, with the indicative signals of a more multilateral order; with the dissemination of the international norms, either in relation to the commerce, as in relation to the right; new countries are created and admitted in the interstates organizations, as well as have reduction of the risks of a thermonuclear war between the global powers. However, in way to the evidences of a multilateralism, the persistence of old problems and the sprouting of new challenges, they continue to impose resistance for a more stable and pacific international arena. With this, it is tried to demonstrate that the conception of the theory of the neoliberal cooperation, with its assumptions and its ontology, determines the formation of an equilibrium that tends to lead for a model of very little stable efficiency. Thus being, it is defended hypothesis of that with the presented model and its ontology they do not objectify the resolution of international disequilibria, therefore, possess between, its consequences, the maintenance of the asymmetries and inequalities between countries and regions. A model of international cooperation that has the stability as constituent would have to consider the resolution of these persistent disequilibria. An international cooperation that keeps the old problems of economic dependence and politics will have great difficulties to establish the conditions for the confrontation of the new happened challenges of the globalization process, that need an ample multilateral participation. The hierarchic methods of the politics reveal insufficient in these circumstances / As ?ltimas d?cadas do s?c. XX e o come?o do s?c. XXI estabelecem o limiar para uma mudan?a de cen?rio nas rela??es internacionais, com os sinais indicativos de uma ordem mais multilateral; com a dissemina??o das normas internacionais, seja em rela??o ao com?rcio, como em rela??o ao direito; novos pa?ses s?o criados e admitidos nas organiza??es interestatais, assim como a h? diminui??o dos riscos de uma guerra termonuclear entre as pot?ncias globais. Contudo, em meio ?s evid?ncias de um multilateralismo, a persist?ncia de velhos problemas e o surgimento de novos desafios continuam a impor resist?ncia para uma arena internacional mais est?vel e pac?fica. Com isso, tenta-se demonstrar que a concep??o da teoria da coopera??o neoliberal, com os seus pressupostos e a sua ontologia, determina a forma??o de um equil?brio que apresenta propens?o a conduzir para um modelo de efici?ncia muito pouco est?vel. Assim sendo, defende-se a hip?tese de que com o modelo apresentado e a sua ontologia n?o objetivam a resolu??o dos desequil?brios internacionais e, por isso, possuem entre, as suas consequ?ncias, a manuten??o das assimetrias e desigualdades entre pa?ses e regi?es. Um modelo de coopera??o internacional que tem a estabilidade como constitutivo deveria considerar a resolu??o desses persistentes desequil?brios. Uma coopera??o internacional que mantenha os velhos problemas de depend?ncia econ?mica e pol?tica ter? grandes dificuldades de estabelecer as condi??es para o enfrentamento dos novos desafios advindos do processo de globaliza??o, que necessitam de uma ampla participa??o multilateral. Os m?todos hier?rquicos da pol?tica mostram-se insuficientes nestas circunst?ncias. Por isso, com base na ontologia da escola construtivista das rela??es internacionais e da escola da sociedade internacional, prop?em-se algumas medidas que podem fornecer um caminho para a constru??o de processos cooperativos mais coerentes e eficazes. Destarte, intenta-se um diverso modelo de equil?brio, com a proposta de um solidarismo dentro de um processo de integra??o regional e internacional, para a estrutura??o de uma ordem global mais leg?tima

Made available in DSpace on 2015-04-14T13:59:07Z (GMT). No. of bitstreams: 1 458199.pdf: 841602 bytes, checksum: b3f962fdf292e2f5967c8998facd1c43 (MD5) Previous issue date: 2014-03-31 / Propolis is a resinous substance produced by bees through the collection of plant secondary metabolites and its chemical composition is complex and varied, giving this product several biological activities such as antibacterial, antifungal and antioxidant. The propolis extract can be obtained by supercritical fluid extraction using CO2 as solvent, which is a clean and non-toxic technology, leaving no residue. This work aims to extract chemically and biologically extracts of green and red propolis produced by bees of the species Apis mellifera. Supercritical CO2 extraction from the raw propolis and its ethanolic extracts, which were impregnated in filter papers, were performed. The pressures used for fractionation of raw propolis were 90, 120, 150, 200, 250 and 300 bar and, for the propolis impregnated in filter papers, 90, 150 and 300 bar. For comparison of the chromatographic profiles at different pressures, chemical analysis using Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC) were done. The chemical composition of the extracts from impregnated propolis ethanolic extracts (PEE) and raw propolis remained similar, but the yield of supercritical extracts from impregnated PEE in filter papers showed much higher values. Supercritical extracts showed antifungal activity and excellent antioxidant activity. / A pr?polis ? uma subst?ncia resinosa produzida pelas abelhas atrav?s da coleta de metab?litos secund?rios da flora e sua composi??o qu?mica ? complexa e variada, conferindo a este produto diversas atividades biol?gicas como antibacteriana, antif?ngica e antioxidante. O extrato da pr?polis pode ser obtido por extra??o supercr?tica, utilizando CO2 como solvente, sendo esta uma tecnologia limpa, at?xica e que n?o deixa res?duo. Este trabalho tem como objetivo extrair e avaliar quimicamente e biologicamente extratos de pr?polis verde e vermelha produzidos pelas abelhas da esp?cie Apis mellifera. Foram realizadas extra??es com CO2 supercr?tico a partir da pr?polis bruta e de seus extratos etan?licos, os quais foram impregnados em pap?is filtro. As press?es utilizadas para fracionamento da pr?polis bruta foram 90, 120, 150, 200, 250 e 300 bar, e da pr?polis impregnada em pap?is filtro, 90, 150 e 300 bar. Para compara??o dos perfis cromatogr?ficos nas diferentes press?es, an?lises qu?micas atrav?s de cromatografia em camada delgada (CCD) e cromatografia l?quida de alta efici?ncia (CLAE) foram realizadas. A composi??o qu?mica dos extratos a partir dos extratos etan?licos de pr?polis (EEP) impregnados e da pr?polis bruta permaneceu similar, por?m o rendimento dos extratos supercr?ticos a partir dos EEP impregnados em pap?is filtro apresentou valores muito mais elevados. Os extratos supercr?ticos obtidos apresentaram atividade antif?ngica e excelente atividade antioxidante.

Made available in DSpace on 2015-04-14T14:13:05Z (GMT). No. of bitstreams: 1 461070.pdf: 661164 bytes, checksum: 0a59c54886caa647b147bc73a87f37bc (MD5) Previous issue date: 2014-03-31 / Students‟ questions have been untapped in chemistry teaching and in scientific inquiry. However, they play an important role to be considered by teachers due to their potential of promoting chemistry learning. For this reason, this work reports a research whose guiding question is: How questions about chemical reactions made by high school students are associated with the conceptual concept presented in textbooks (PNLD, 2012) and what are the recommendations in official educational documents regarding high school? Students‟ questions related to what they would like to learn about chemical reactions, The National Program of the Textbook 2012 and its collections as well as official educational documents (PCN, PCN+ e OCN) were the sources of data which was analyzed using the Textual Discourse Analysis (DTA) as theoretical basis. The official documents were used during the analysis. The main results of this research are: after a comparison as well as an analysis of data, it can be concluded that there is a relation among students‟ questions, textbooks as well as official educational documents. Nevertheless, besides the relation among them, it is relevant to emphasize the essential role of the teacher in order to connect these three points / As perguntas dos estudantes s?o pouco valorizadas no ensino de Qu?mica e na pesquisa nessa ?rea. No entanto, s?o elementos importantes a serem considerados pelos professores pela sua possibilidade de promover a aprendizagem em Qu?mica. Por isso, o trabalho relata investiga??o, cuja quest?o norteadora ?: Como as perguntas dos estudantes de ensino m?dio sobre rea??es qu?micas relacionam-se com a apresenta??o desse conte?do conceitual nos livros did?ticos (PNLD 2012) e com o que recomendam os documentos educacionais oficiais do ensino m?dio? Perguntas de estudantes sobre o que gostariam de aprender acerca das rea??es qu?micas, as cole??es de livros did?ticos do Programa Nacional do Livro Did?tico (PNLD) de 2012 e os documentos educacionais oficiais (PCN, PCN+ e OCN) foram as fontes de dados, analisadas por meio da An?lise Textual Discursiva (ATD). Ap?s, foram integradas essas an?lises, pela produ??o de textos compreensivos e interpretativos. Os principais resultados dessa investiga??o s?o os seguintes: ap?s uma compara??o e compreens?o das an?lises, pode-se concluir que existe uma rela??o entre as perguntas, os livros e os documentos. Por?m, al?m das rela??es existentes ? importante salientar a import?ncia do professor para realizar uma conex?o entre as partes

Made available in DSpace on 2015-04-14T14:13:08Z (GMT). No. of bitstreams: 1 346355.pdf: 484836 bytes, checksum: 61259056edac130672c934ca399b7669 (MD5) Previous issue date: 2006-01-25 / A presente pesquisa ? o relato da an?lise sobre que contribui??es a proposta de trabalho unidades de aprendizagem pode trazer ao processo de constru??o da cidadania na disciplina de qu?mica. Por meio da an?lise de depoimentos e de situa??es em sala de aula, s?o apresentadas neste trabalho as diversas atividades que auxiliaram na constru??o da aprendizagem em qu?mica e que levam o aluno ? aplica??o do conte?do no seu cotidiano. O estudo foi aplicado a dezoito alunos do Ensino M?dio de uma Escola P?blica de Porto Alegre e foi desenvolvido com a proposta do educar pela pesquisa, no qual os alunos conciliaram o (pr?)conhecimento com o novo conhecimento qu?mico, desenvolvendo a pesquisa e o di?logo em sala de aula, tendo o professor como mediador do processo de aprendizagem. Os estudos te?ricos discorrem sobre a pesquisa em sala de aula, unidade de aprendizagem, autonomia, constru??o da cidadania e professor como agente transformador. A an?lise dos dados me fez verificar que ? poss?vel criar condi??es em aula para a constru??o da cidadania em um conte?do da ?rea cient?fica. O desenvolvimento da unidade de aprendizagem permitiu que as id?ias pr?vias dos alunos fossem contempladas, associadas ao conte?do estudado e aplicadas no cotidiano. Assim, foi poss?vel identificar fatores que levam o aluno no caminho da constru??o da cidadania.

Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-05-04T17:15:51Z No. of bitstreams: 1 TES_HENRIQUE_VIEIRA_FIGUEIRO_COMPLETO.pdf: 4680551 bytes, checksum: 8695b78fe6812f4690586975941c4c31 (MD5) / Made available in DSpace on 2017-05-04T17:15:51Z (GMT). No. of bitstreams: 1 TES_HENRIQUE_VIEIRA_FIGUEIRO_COMPLETO.pdf: 4680551 bytes, checksum: 8695b78fe6812f4690586975941c4c31 (MD5) Previous issue date: 2016-03-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / In the past 10 years, high throughput sequencing has revolutionized evolutionary biology. With the technical advances that emerged with the genome sequencing of model species, it is now possible to apply these techniques to taxonomic groups without any previously available genetic resources. Complete genome sequencing and reduced representation methods have enabled us to explore deeper evolutionary questions, such as detecting ancient hybridization and signatures of selection on a genomic scale. Among the groups that could benefit from these methods is the Panthera genus. The group is composed by five species (P. onca, P. tigris, P. leo, P. pardus and P. uncia), all of which are large felids that exert important ecological role as apex predators in their habitats. Their low densities, alarming rates of habitat loss and chronic conflict with humans, all of them are threatened with extinction in the wild and thus important targets for conservation. One of the species in this group, the jaguar (P. onca), is the only member of the genus currently present in the Neotropical region, and the focus of our study. The jaguar has a color pattern similar to that of the leopard, but a much more robust constitution, with massive jaws and shorter limbs. The present study aims to characterize for the first time the jaguar genome, and to perform comparative analyses with the genomes from all other Panthera species. In addition, we seek to perform population genomic analyses with Brazilian jaguar populations and search for signatures of divergent selection in different regions. We have sequenced four genomic libraries, with an estimated coverage depth of 84x. The complete genome sequence allowed the annotation of 25,441 genes and the description of other genomic features (e.g. ncRNA, microsatellites, numts). Additionally, we have sequenced the genome of a leopard at low coverage, with an estimated depth of 25x. With the addition of these two genomes, we were able obtain a genomic data set containing all five Panthera species, which was used to perform phylogenetic discordance analyses and to detect signatures of selection using a dataset encompassing 13,143 orthologous genes. We were able to demonstrate the presence of hybridization events during the speciation process of the species, as well as signatures of selection in genes potentially involved in important characteristics of these iconic animals. Among them, the jaguar?s robust build, the social behavior of lions, cold environment adaptations in the snow leopard and the tiger?s stripes. Using an exome capture approach, we performed a population genomics study targeting jaguar populations from different Brazilian biomes. In addition to assessments of genetic diversity and population structure, we detected signals of local adaptation using multiple methods. Among the obtained results is the presence of genes under selection that are related to energetic metabolism in the Amazon, body development in the Pantanal and immunity in the Atlantic Forest. Additionally, we observed several pigmentation-related genes under selection in different biomes. Those genes affect not only pigmentation, but also have pleiotropic effects in development and immunity routes. Overall, these results help to understand the evolutionary processes that have shaped the adaptation of Panthera species, and particularly the jaguar, to the environments where they currently live. / Nos ?ltimos 10 anos, o sequenciamento gen?mico de alto desempenho revolucionou a biologia evolutiva. Com os avan?os gerados pelo sequenciamento do genoma completo de esp?cies modelo, agora ? poss?vel aplicar essas t?cnicas em animais com praticamente nenhum recurso gen?tico dispon?vel. O sequenciamento completo de genomas, bem como o uso de t?cnicas de representa??o reduzida, permitem explorar quest?es evolutivas complexas como, por exemplo, detec??o de hibrida??o e assinaturas de sele??o natural em uma escala gen?mica. Dentre os grupos taxon?micos que podem se beneficiar de tais t?cnicas est? o g?nero Panthera. O grupo ? composto por cinco esp?cies atuais (P. onca, P. tigris, P. leo, P. pardus e P. uncia), todas elas apresentando grande porte e atuando como predadores de topo nos ambientes que ocupam. Devido ?s baixas densidades, alarmante perda de habitat e constantes conflitos com humanos, o n?vel de amea?a em que essas esp?cies se encontram ? preocupante. Dentre as esp?cies do grupo, est? a on?a-pintada (P. onca), ?nica integrante do g?nero na regi?o Neotropical e o principal foco deste trabalho. Nesse sentido, o presente estudo busca caracterizar pela primeira vez o genoma da on?a-pintada, incluindo an?lises comparativas com as outras quatro esp?cies do g?nero. Al?m disso, o trabalho tem como objetivo avaliar as popula??es de on?a no Brasil e buscar assinaturas de sele??o divergente nos biomas que ela ocupa. Para o sequenciamento do genoma da esp?cie, foram utilizadas quatro bibliotecas gen?micas, com uma cobertura estimada de 84x. A sequ?ncia do genoma completo permitiu a anota??o de 25.441 genes e a descri??o de outros componentes do genoma (p.ex. ncRNA, microssat?lites, numts). Adicionalmente, foi sequenciado o genoma de um leopardo (P. pardus) com cobertura estimada de 25x. Com esses dois novos genomas, completou-se um conjunto abrangendo todas as cinco esp?cies do g?nero, permitindo a realiza??o de an?lises de discord?ncia filogen?tica para o grupo e detec??o de sele??o positiva utilizando um conjunto de 13.143 genes ort?logos. Foi poss?vel demonstrar eventos de hibrida??o durante o processo de especia??o das esp?cies do g?nero, bem como sinais de sele??o positiva em genes envolvidos em caracter?sticas que se destacam nos grandes fel?deos. Entre eles, fen?tipos potencialmente afetados por genes sob sele??o incluem o cr?nio e membros robustos da on?a-pintada, o comportamento social no le?o, adapta??o ao frio no leopardo das neves e a presen?a de listras no tigre. Com o uso de captura de exoma, que tem como objetivo o sequenciamento do conjunto de exons da esp?cie, foi poss?vel realizar uma nova avalia??o das caracter?sticas gen?ticas de popula??es de on?a-pintada, bem como a detec??o de assinaturas de adapta??o local. Entre os resultados obtidos est? a presen?a de genes sob sele??o relacionados com metabolismo energ?tico em popula??es da Amaz?nia, adapta??es relacionadas com desenvolvimento corporal no Pantanal e imunidade na Mata Atl?ntica. Adicionalmente, foram observados diversos genes de pigmenta??o com assinaturas de sele??o em diferentes biomas. Esses genes, al?m de afetarem a colora??o dos animais, possuem efeitos pleiotr?picos no desenvolvimento e imunidade da esp?cie. Esses resultados auxiliam no entendimento dos processos evolutivos que moldaram a adapta??o das esp?cies do g?nero, e em especial a on?a pintada, aos ambientes que elas ocupam atualmente.

Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-05-26T17:50:16Z No. of bitstreams: 1 TES_MARIANE_ROTTA_PARCIAL.pdf: 2374056 bytes, checksum: 0b798c90ce9ab78e6edbfeb524d79d97 (MD5) / Made available in DSpace on 2017-05-26T17:50:17Z (GMT). No. of bitstreams: 1 TES_MARIANE_ROTTA_PARCIAL.pdf: 2374056 bytes, checksum: 0b798c90ce9ab78e6edbfeb524d79d97 (MD5) Previous issue date: 2016-12-19 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / The cellular milieu is a complex and crowded aqueous solution. It is thus expected that this large concentration of macromolecules causes deviations from solution ideality. To mimic the intracellular environment, crowding effects are commonly studied in vitro using crowding agents. The aim of the present study was to evaluate the effects of macromolecular synthetic crowding agents on the apparent steady-state kinetic parameters (Km, kcat, and kcat/Km) for the chemical reaction catalyzed by 2-trans-enoyl-ACP (CoA) from Mycobacterium tuberculosis (InhA). The results showed that ficoll 70, ficoll 400, and dextran 70 had negligible effects on InhA activity in the range of concentrations used. On the other hand, a complex effect was observed for PEG 6000. Sucrose, which was employed in control experiments, decreased both the kcat/Km values for NADH and kcat for 2-trans-dodecenoyl-CoA (DD-CoA) substrate in a concentration-dependent manner. Molecular dynamics results suggest that InhA adopts a more compact conformer in sucrose solution, which likely accounts for the steady-state kinetic results. The presence of crowding agents appears to alter the relative abundance of different conformers of InhA in solution. The effects of the crowding agents on the energy (Ea and E?), enthalpy (?H#), entropy (?S#), and Gibbs free energy (?G#) of activation were determined. The ?G# values for all crowding agents tested were similar to dilute buffer, suggesting that excluded volume effects did not facilitate stable activated ES# complex formation. Nonlinear Arrhenius plot for PEG 6000 suggests that "soft" interactions may play a role in macromolecular crowding effects. / O meio intracelular ? uma solu??o aquosa complexa, pois ? preenchida por diversos tipos de macromol?culas. Espera-se que essa grande concentra??o de macromol?culas resulte em um comportamento n?o ideal para a solu??o. Para mimetizar o ambiente intracelular, os efeitos do da ocupa??o macromolecular s?o comumente estudados in vitro utilizando agentes de crowding. O objetivo central do presente estudo ? avaliar os poss?veis efeitos de agentes de crowding macromolecular sint?ticos nos par?metros cin?ticos aparentes de estado-estacion?rio (Km, kcat e kcat/Km) para a rea??o qu?mica catalisada pela 2-trans-enoil-ACP(CoA) redutase de Mycobacterium tuberculosis (InhA). Os resultados mostraram que ficoll 70, ficoll 400 e dextran 70 t?m efeitos negligenci?veis na atividade da InhA na faixa de concentra??o utilizada. Por outro lado, um complexo efeito foi observado na presen?a do PEG 6000. A sacarose, que foi utilizada como controle nos experimentos, reduziu os valores de kcat/Km para o NADH e kcat para o 2-trans-dodecenoil-CoA de uma maneira concentra??o-dependente. Os resultados de din?mica molecular sugerem que a InhA adota uma forma mais compacta na presen?a de sacarose, o que provavelmente tem efeitos nos resultados de cin?tica de estado-estacion?rio. A presen?a dos agentes de crowding parece alterar a abund?ncia relativa dos diferentes conf?rmeros da InhA em solu??o. Os efeitos do crowding macromolecular na energia (Ea e E?), entalpia (?H#), entropia (?S#) e energia livre de Gibbs de ativa??o (?G#) foram determinados. Os valores de ?G# para todos os agentes de crowding testados foram similares ao tamp?o Pipes 100 mM, sugerindo que os efeitos do volume exclu?do n?o facilitam a forma??o do complexo ativado est?vel ES#. A n?o linearidade do gr?fico de Arrhenius para o PEG 6000 sugere que intera??es ?brandas? possam atuar nos efeitos do crowding macromolecular.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2015-06-18T11:43:04Z No. of bitstreams: 1 470756 - Texto Completo.pdf: 1248659 bytes, checksum: ab80152728008387d3afbc02430bbd66 (MD5) / Made available in DSpace on 2015-06-18T11:43:04Z (GMT). No. of bitstreams: 1 470756 - Texto Completo.pdf: 1248659 bytes, checksum: ab80152728008387d3afbc02430bbd66 (MD5) Previous issue date: 2015-03-26 / The study on the influence of the student's question on learning in Chemistry in action research in the classroom contribute to answer the following question: how the elaboration and discussion of questions for high school students contribute to their learning in chemistry? The research was conducted with students of the 3rd year of high school at a private school of the Porto Alegre city. Initially, the research subjects proposed questions about what they would like to know about alcohol. The questions were analyzed, categorized and served the basis for the organization of a Learning Unit (AU). Based on frequently asked questions, was developed and applied an initial test to identify the knowledge of the students. After completion of the activities of the AU, in order to build students' answers to questions, a final test was applied, similar to the initial test. Thus, we performed a comparative analysis between the two tests. A questionnaire was also on the perceptions of students in relation to the fact studying chemistry from their own questions. The investigation allowed us to consider the questions of the students contribute to their learning because mobilize their curiosity, influencing him to take up subjects of their learning. Allowed the reconstruction of knowledge under the theme generator in a broad perspective (scientific, technological and social), as it was associated with students' experiences and their daily lives. The dialogue with the teacher and classmates, aiming to construct answers to questions stimulated the construction of arguments, so that the teaching of chemistry began to have meaning for students. / O estudo sobre a influ?ncia da pergunta do aluno na aprendizagem em Qu?mica, em a??es de pesquisa na sala de aula, buscou responder ? seguinte quest?o: como a elabora??o e a discuss?o de perguntas pelos alunos de Ensino M?dio contribuem para a sua aprendizagem em Qu?mica? A investiga??o foi realizada com alunos do 3? Ano do Ensino M?dio de uma escola privada, do Munic?pio de Porto Alegre. Inicialmente, os sujeitos de pesquisa propuseram perguntas sobre o que gostariam de saber sobre o ?lcool. As perguntas foram analisadas, categorizadas e serviram de base para a organiza??o de uma Unidade de Aprendizagem (UA). Com base nas perguntas mais frequentes, foi elaborado e aplicado um teste inicial para identificar os saberes dos alunos. Ap?s a realiza??o das atividades da UA, com vistas a construir respostas ?s perguntas dos alunos, foi aplicado um teste final, semelhante ao teste inicial. Assim, foi realizada uma an?lise comparativa entre os dois testes. Tamb?m foi aplicado um question?rio sobre as percep??es dos alunos em rela??o ao fato de estudar a Qu?mica a partir das suas pr?prias perguntas. A investiga??o permitiu considerar que as perguntas dos alunos contribuem para sua aprendizagem, pois mobilizam sua curiosidade, influenciando-os a assumirem-se sujeitos do seu aprender. Permitiu a reconstru??o de saberes sobre o tema gerador, numa perspectiva ampla (cient?fica, tecnol?gica e social), na medida em que esteve associado ?s viv?ncias dos alunos e ao seu cotidiano. O di?logo com a professora e os colegas, visando construir respostas ?s perguntas estimulou a constru??o de argumentos, de modo que o ensino de Qu?mica passou a ter significado para os estudantes.

De nombreuses études ont montré l’impact de la déformation sur le système K-Ar, et donc les âges ⁴⁰Ar/³⁹ Ar. Ces études se limitent souvent à une comparaison des âges obtenus dans des roches déformées et un protolithe indemne de déformation. La première partie de cette étude a inversement consisté à étudier la distribution de la déformation à différentes échelles et à décrire finement les gradients d’intensité de la déformation. L’étude a porté sur deux protolithes de nature granitique, associés à une différence d’âge entre leur formation et les évènements tectonométamorphiques faible (< 1 Ma ; massif d’Ikaria) ou élevée (>240 Ma ; massif du Tende). Pour le premier cas, la déformation entraine une perte de 40Ar dans les clastes des phases potassiques, interprétée comme résultant de la réduction des tailles des domaines de diffusion qui n’est pas accentuée par une intensité de déformation croissante. Pour le second cas, l’héritageen 40Ar du protolithe se traduit par la circulation de fluides et de 40Ar externe au système via les structures se déformant activement, produisant parfois un vieillissement des âges grandissant dans la phengite des structures les plus localisantes, alors que sur d’autres coupes il est observé un rajeunissement plus logique. Pour les deux cas,l’interprétation des âges obtenus dans les phases néoformées pendant la déformation est ambiguë entre refroidissement,cristallisation et mélange, et nécessite un examen détaillé des données confrontées aux températures de fermeture possibles. Les interprétations indiquent pour le cas d’Ikaria une localisation de la déformation ductile en moins de 1-3Ma le long d’un gradient de second ordre d’une dizaine de mètre d’épaisseur. La localisation de la déformation à l’échelle d’une zone de cisaillement se réalise plus rapidement dans le cas de l’exhumation post-orogénique d’un MCC(~7 Ma) que dans le cas de l’exhumation de matériel continental impliqué dans un prisme de subduction (~14-10 Ma). / Numerous studies have shown the impact of deformation on the K-Ar system, and therefore ⁴⁰Ar/³⁹ Ar ages. These studies often do not provide data characterizing deformation and are limited to a comparison of the ages obtained indeformed rocks and an undeformed protolith. The first part of this study thus consisted in studying the strain distribution at different scales and finely describing strain intensity gradients. The study focused on two granitic protoliths, associated respectively with a difference in age between the formation of the protolith and the age of the tectonometamorphic events that is low (<1 Ma ; Ikaria Island) or inversely high (> 240 Ma ; Tenda massif). In the firstcase study, deformation results in a 40Ar loss in K-bearing phases, interpreted as resulting from the reduction of diffusion domains sizes which is not accentuated by an increasing strain intensity. In the second case study, the 40Arinheritance of the protolith results in fluids and extraneous 40Ar circulation through the actively deforming structures,ages in phengite being increasingly older approaching the most localizing structures in some sections, while others behave in an opposite way, more in line with the progressive strain localization in time. For both cases, interpretation of ages obtained in the newly formed phases during deformation is ambiguous between cooling, crystallization and mixing, and requires a detailed examination of the data confronted with the possible closing temperatures.Interpretations indicate for the Ikaria case study a strain localization in less than 1-3 Ma along a second order gradient of about ten meters in thickness. Strain localization at the scale of a shear zone occurs more rapidly in the case of a post-orogenic exhumation of a MCC (~ 7 Ma) than in the case of the exhumation of continental material involved in a subduction prism (~ 14-10 Ma).