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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Aduba??o NPK no crescimento e produ??o de pinh?o manso. / Assessment of NPK fertilization in plants production and in field cultivation of physic nut to biodiesel production.

Souza, Patr?cia Teixeira de January 2010 (has links)
Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T13:30:31Z No. of bitstreams: 5 16.pdf: 2264246 bytes, checksum: 0428b3049c41136d0034fb8c5bcbc678 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20904 bytes, checksum: e09bf99e64678e4285abf3ef3e05412d (MD5) license_rdf: 23422 bytes, checksum: b145eda3d84bdc4f56b389c0ab98d368 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T14:56:22Z (GMT) No. of bitstreams: 5 16.pdf: 2264246 bytes, checksum: 0428b3049c41136d0034fb8c5bcbc678 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20904 bytes, checksum: e09bf99e64678e4285abf3ef3e05412d (MD5) license_rdf: 23422 bytes, checksum: b145eda3d84bdc4f56b389c0ab98d368 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) / Made available in DSpace on 2015-02-27T14:56:22Z (GMT). No. of bitstreams: 5 16.pdf: 2264246 bytes, checksum: 0428b3049c41136d0034fb8c5bcbc678 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20904 bytes, checksum: e09bf99e64678e4285abf3ef3e05412d (MD5) license_rdf: 23422 bytes, checksum: b145eda3d84bdc4f56b389c0ab98d368 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) Previous issue date: 2010 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / A grande demanda de ?leos vegetais no Brasil, gerada pelo Programa Brasileiro de Biodiesel, fez com que o pinh?o manso, uma esp?cie at? ent?o desvalorizada, se tornasse alternativa para fornecimento de mat?ria-prima. Por?m, muitos s?o os estudos que devem ser realizados, antes que se inicie o plantio comercial em larga escala. O manejo correto da aduba??o eleva o lucro do produtor de duas formas. Primeiro, evita o gasto de fertilizantes em quantidades erradas e, depois, favorece o melhor desempenho da planta, proporcionando maior produtividade. Este trabalho objetivou avaliar a resposta do pinh?o manso (Jatropha curcas L.) a doses de NPK no crescimento de plantas e, no crescimento de plantas, produ??o de sementes e de ?leo em duas condi??es edafoclim?ticas. Para tanto, foram montados dois experimentos: o primeiro, em condi??es de casa de vegeta??o, teve os tratamentos dispostos em delineamento inteiramente casualizado, no esquema de fatorial fracionado (4x4x4)1/2, perfazendo 32 tratamentos com tr?s repeti??es, totalizando 96 parcelas experimentais, sendo as doses de N: 0, 75, 150 e 300 mg dm-3, na forma de ur?ia; doses de P: 0, 45, 90 e 180 mg dm-3, na forma de superfosfato triplo e doses de K: 0, 50, 100 e 200 mg dm-3, na forma de cloreto de pot?ssio. Ap?s 120 dias, foram avaliadas as seguintes vari?veis: altura das plantas, di?metro do caule, massa seca da parte a?rea e de ra?zes; an?lise qu?mica do solo ap?s a colheita das plantas e teor de macro e micronutrientes na parte a?rea das plantas. O segundo foi conduzido em campo, em duas condi??es edafoclim?ticas, em Diamantina e Governador Valadares, Minas Gerais. Ambos foram conduzidos da mesma forma: o delineamento utilizado foi o delineamento em blocos casualizados no esquema de fatorial fracionado (4x4x4)1/2, perfazendo 32 tratamentos. Foram aplicadas doses de N: 0, 25, 50 e 100 kg ha-1, na forma de ur?ia; doses de P2O5: 0, 75, 150 e 300 kg ha-1, na forma de superfosfato triplo e as doses de K: 0, 50, 100 e 200 kg ha-1, na forma de cloreto de pot?ssio. Foram avaliados o crescimento das plantas pela medi??o da altura de plantas e di?metro na altura do colo do caule a cada 30 dias; produ??o de sementes e de ?leo com uma colheita em Diamantina, em 2009, e duas colheitas em Governador Valadares, em 2008 e 2009. As plantas responderam negativamente ? adi??o de N e positivamente ao P e K , mostrando que o pinh?o manso ? eficiente na absor??o de N, que foi suprido pela mat?ria org?nica do solo. J? em campo, o pinh?o manso apresentou comportamentos distintos nas duas condi??es edafoclim?ticas. Em Governador Valadares, houve resposta positiva ? aplica??o de N e, em Diamantina, resposta negativa a N e positiva a P. N?o houve resposta a K em campo, indicando que o teor do solo foi suficiente para suprir a planta em todas as fases. No experimento de vaso, as doses de P e K recomendadas foram 25 e 67 mg dm-3, respectivamente. Os n?veis cr?ticos, correspondentes ?s doses recomendadas, foram de 10,6 para P e 74,0 mg dm-3 para K no solo (Mehlich-1). Para os teores na massa seca da parte a?rea do pinh?o manso foram de 3,74; 0,18 e 3,57 dag kg-1 para N, P e K, respectivamente. As doses recomendadas de P para o crescimento, a produ??o de sementes e de ?leo de pinh?o manso em Diamantina foram de 87, 72 e 72 kg de P2O5 por ha, respectivamente. Em Governador Valadares, n?o houve recomenda??o de aduba??o nitrogenada para a fase de crescimento das plantas; para a produ??o de sementes e de ?leo, a dose recomendada foi de 36 e 31 kg ha-1 de N, respectivamente. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2010. / ABSTRACT The great demand for vegetable oils in Brazil, generated by the Brazilian Biodiesel Program, made the physic nut, a devalued specie, become an alternative for providing raw material. However, many studies must be carried out before beginning the large-scale commercial growing. The accurate fertilization increases the producer's profit in two ways, first avoids the fertilizers expense in the wrong quantities and then promotes better plant performance for higher productivity. This study evaluated the physic nut (Jatropha curcas L.) response to NPK doses on seedlings growth and plant growing, seed and oil production in two edaphic and climate conditions. Therefore, there were arranged two experiments: the first, in controlled conditions, was arranged in a completely randomized design, in the fragmented factorial scheme (4x4x4)1/2 comprising 32 treatments with three replicates totaling 96 plots and the N doses: 0, 75, 150 e 300 mg dm-3, in the urea form; P doses: 0, 45, 90 and 180 mg dm-3, in the triple superphosphate form and K doses K: 0, 50, 100 and 200 mg dm-3, in the potassium chloride form. After 120 days, there were evaluated the following variables: seedlings height, stem diameter, the shoot and roots dry mass and nutrients content in the soil and in the seedling shoot macronutrients and micronutrients. The second was conducted in field conditions on two places with distinct edaphic and climate conditions, Diamantina, MG and Governador Valadares, MG. Both were conducted in the same way, the design was in randomized blocks, in the fractional factorial scheme (4x4x4) 1 / 2. The N doses were applied: 0, 75, 150 and 300 mg dm-3, in urea form; P doses: 0, 45, 90 and 180 mg dm-3, in the form of triple superphosphate and K doses: 0, 50, 100 and 200 mg dm-3, in the potassium chloride form. There were evaluated the plants growth by the measure of plants height, stem diameter every 30 days, seeds and oil production with one harvest in Diamantina in 2009 and two harvests in Governador Valadares in 2008 and 2009. Seedlings responded negatively to N addition and positively to P, showing that physic nut is efficient in N uptake that was supplied by soil organic matter. Therefore, in the field physic nut showed different behavior in both edaphic and climate conditions. In Governador Valadares there was positive response to N application and in Diamantina there was negative response to N and positive for P. There was no response to K in either experiment, indicating that the content of the soil was sufficient to supply the plant at all stages. Seedlings responded negatively to N addition and positively to P. There was no response to K field, indicating that the content of the soil was sufficient to overcome the plant at all stages. In pot experiment the recommended doses of P and K were 25 and 67 mg dm-3, respectively. The critical level corresponding to the recommended dose, were 10.6 for P and 74.0 mg dm-3 for K in soil (Mehlich-1). For contents in shoot dry mass of physic nut seeds were 3.74, 0.18 and 3.57 dag kg-1 for N, P and K, respectively. The P recommended doses for growth, seeds and oil of physic nut in Diamantina was 87, 72 and 72 kg P2O5 per ha, respectively. In Governador Valadares, there was no nitrogen indication for the plants growth phase, for oil and seeds production and the recommended dose was 36 and 31 kg ha-1 N, respectively.
22

S?ntese de ?steres versus eterifica??o e de 1,3 e 1,5-dioxolanas versus condensa??o, catalisadas pelo catalisador amorfo e hidrof?lico, SiO2-SO3H

Ottone, Myrlene de Oliveira 09 September 2016 (has links)
?rea de concentra??o: Qu?mica org?nica. / Data de aprova??o retirada da vers?o impressa do trabalho. / Palavras-chave ausentes no Resumo/Abstract. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-08-04T17:58:56Z No. of bitstreams: 2 myrlene_oliveira_ottone.pdf: 35150534 bytes, checksum: f6a5ce4d99508eed910f62e1d6984580 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-08-14T13:58:08Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) myrlene_oliveira_ottone.pdf: 35150534 bytes, checksum: f6a5ce4d99508eed910f62e1d6984580 (MD5) / Made available in DSpace on 2017-08-14T13:58:08Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) myrlene_oliveira_ottone.pdf: 35150534 bytes, checksum: f6a5ce4d99508eed910f62e1d6984580 (MD5) Previous issue date: 2016 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O SiO2-SO3H ? um catalisador heterog?neo, sintetizado a partir de areia de constru??o e carbonato de s?dio, o qual, vem se mostrando eficaz nas s?nteses org?nicas. No presente trabalho, esse catalisador foi usado na s?ntese de ?steres benz?licos e fen?licos, realizada em apenas uma ?nica etapa, com rendimentos entre 80 e 95%. E devido a esse alto rendimento, foi tamb?m realizado rea??es de cetaliza??es, utilizando glicerol, 2,2-dimetil-1,3-propandiol e 1,1,1-hidroximetil-propanol e diversas cetonas. As rea??es com o glicerol apresentaram rendimentos baixos, por ser uma esp?cie muito polar e interagir com os poros da s?lica, evitando a colis?o com as mol?culas de cetonas. Diante desses resultados, foi poss?vel produzir um catalisador heterog?neo que al?m de diminuir o impacto ambiental, carrega caracter?sticas ben?ficas e eficientes para s?ntese org?nica, poss?vel se tonar eficaz para futuras rotas sint?ticas. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / The SiO2 - SO3H is a heterogeneous catalyst synthesized from building sand and sodium carbonate. It has proven to be effective for organic syntheses. In study the catalyst was used in the synthesis of benzyl esters and phenolics and the yields between 80 and 95%. And the high yield was also performed cetaliza??es reactions using glycerol, 2,2- dimethyl- 1,3- propandiol and 1,1,1 -hydroxymethyl- propanol and various ketones. The reactions with glycerol had low yield justified very polar species and interact with the pores of silica, avoiding collision with ketone molecules. These results it was possible to produce a heterogeneous catalyst in addition to reducing environmental impact, carries beneficial and efficient features for organic synthesis. It can be effective tonar for future synthetic routes.
23

Testování účinků \kur{o}-fosfonatomethylcholinu a jeho analogů proti leishmaniím. / Testing of effects of the \kur{o}-phosphonatomethylcholine and its analogues against \kur{Leishmania.}

MATOUŠOVÁ, Linda January 2010 (has links)
The term leishmaniasis can be used to define a group of diseases caused by the Leishmania genus. Human infection may be entirely unapparent or sub-clinical or it may display a spectrum of manifestations ranging from cutaneous involvement throug to the late destruction of the mucous membranes and on to a generalised systemic visceral disease with a fatal outcome. Phosphatidylcholine is the most abundant phospholipid in this parasite{\crq}s membranes. The metabolic pathways leading to biosynthesis are likely to play a critical role in the parasite{\crq}s development and survival and may offer a good target for antileishmanial chemotherapy. Phosphatidylcholine synthesis requires the transportation of a choline precursor from the host. This choline transportation into Leishmania is highly specific for choline and is inhibited by phosphocholine analogues and choline analogues. The aim of this study was to test the effects of the analogues of o-phoshonatomethylcholine and the analogues of phosphocholine for antileishmanial activity.
24

Fotografia para ver e pensar

Leite, Amanda Mauricio Pereira January 2016 (has links)
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências de Educação, Programa de Pós-Graduação em Educação, Florianópolis, 2016. / Made available in DSpace on 2016-05-24T17:54:36Z (GMT). No. of bitstreams: 1 339600.pdf: 6153900 bytes, checksum: 2159ce362fe1dd14b0436cfe9ab0b036 (MD5) Previous issue date: 2016 / Qual é o lugar da Ficção na Educação? Esta questão inspira e conduz a pesquisa. Aqui, procuro explorar em três movimentos o campo educacional e a produção de visualidades que se dá pela Fotografia. I) pensar sobre as conexões existentes entre: ficção/fotografia/educação; II) pensar sobre a composição de narrativas visuais; III) propor experimentos fotográficos para pensar o lugar da Ficção na Educação. A escolha metodológica faz um exercício de deslocamento conceitual, isto é, cria um jogo de montagem ou uma relação entre conceitos, teorias e fotografias de modo a liberar a leitura de certos discursos e pensamentos para outras possibilidades de ver e pensar. Nesta escrita labiríntica, sugiro uma espécie de contágio, uma afetação, uma escrita que dança, que vê e que pensa com a fotografia. Uma escrita que se instala na fronteira e se assume como experimento artístico. Intercala exercícios fotográficos, concepções conceituais e possibilidades educativas. A forma de expressão puxa a forma dos conteúdos. Nesta zona propensa à contaminação vejo a fotografia e a ficção como potências, por isso exploro seus deslocamentos especialmente na área da Educação. Para além de um exercício artístico e pedagógico, busco um modo de pensar a imagem mais experimental, suponho um movimento nômade que se deixa contaminar, afinal: nossos olhos podem ver, mas o que e como veem?<br> / Abstract : What is the place of fiction in Education? This question inspires and conducts this research. Here, I try to explore in three movements the field of Education and the production of visibility by Photography I) thinking about the connections between: fiction/photography/education; II) thinking about the composition of visual narratives; III) proposing photographic experiments to think about the place of fiction in Education. The methodological choice makes an exercise of conceptual displacement, that means, it creates a composition or a relationship between concepts, theories and photographs in order to release the reading from certain discourses and thoughts to other ways of seeing and thinking. In this labyrinthine writing, I suggest a kind of contagion, an affectation, a written which dances, sees and thinks with Photography. A written that installs itself on the border as an artistic experiment. The form of expression pulls the shape of the contents. In this zone of contamination, I see the Photography and fiction as powers, so, I explore their displacement especially in Education. Apart from an artistic and pedagogical exercise, I seek an experimental way of thinking the image, I presume a nomadic movement that let itself contaminate, after all: our eyes can see, but what and how they see?
25

Corpo em Nietzsche

Costa, Thalita Schuh Venancio da January 2016 (has links)
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Educação, Programa de Pós-Graduação em Educação, Florianópolis, 2016. / Made available in DSpace on 2016-05-24T17:56:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2016 / Esta pesquisa aborda o corpo em Nietzsche sob a ótica do problema da unidade do sujeito. Centra-se, sobretudo, na crítica do filósofo à noção de sujeito da tradição humanista, a qual, segundo ele, decorre de um longo processo histórico forjado, desde o princípio, pela dicotomia platônica entre corpo e alma. No decorrer do trabalho pretende-se apresentar como a tradição filosófica ocidental conceituou o corpo, e como, de certa forma, nossa ?cultura educacional? parece tributária dessa conceituação. As fontes principais de investigação sobre o corpo em Nietzsche são constituídas da seção ?Dos desprezadores do corpo?, presente em Assim falou Zaratustra, e de alguns aforismos do autor, de outras obras, que dialogam com o tema em questão. Parte-se da hipótese que, ao se considerar e investigar a noção de corpo em Nietzsche, novas possibilidades podem surgir para se pensar a educação.<br> / Abstract : This research addresses the body in Nietzsche from the problem of the unity of the subject perspective. It mainly focuses on the criticism of the philosopher to the subject of humanistic tradition notion, which, he said, stems from a long wrought historical process by a Platonic dichotomy between body and soul since the beginning. This essay aims to clarify how the Western philosophical tradition had conceptualized the body, and how, in a way, our "educational culture" seems debtor of this concept. The main sources of this research about the body in Nietzsche come from the chapter "The despisers of the body" of the book Thus Spoke Zarathustra. They also come from some author aphorisms from other works that dialogue with the main theme of this essay. It starts with the hypothesis that, when considering and investigating the notion of the body in Nietzsche, new possibilities may arise to think about education.
26

Sistema experto de determinación de autoavaluo

Robles Sánchez, Rosalía Isabel, Quispe Alfaro, Amelia January 2002 (has links)
El presente trabajo tiene como propósito fundamental, efectuar el diseño e implantación de un Sistema Experto de Determinación de Autoavaluo, orientada a cualquier Municipalidad de nuestro país. Para ello, se describe previamente aspectos teóricos de lo que es un Sistema Experto, Análisis Tributario y la Metodología empleada en el desarrollo de dicho Sistema, denominada “Redes Neuronales Artificiales”. / --- The present work has a main purpose to develop the design and implantation of expert system to determine the autoavaluo, be guided to any municipality of our country. For this, theoretical aspects about Expert Systems, Tax Analysis and the methodology used in the developing of the system, called “Artificial Neuronal Network”.
27

Etude des relations "O-GlcNAcylation et microdomaines lipidiques" / Study of relationship "lipid microdomaines and O-GlcNAcylation"

Pérez-Cervera, Yobana 11 May 2012 (has links)
La O-GlcNAcylation est une modification post-traductionnelle appartenant au groupe des glycosylations. C’est une modification dynamique, analogue à la phosphorylation, dont la réversibilité est contrôlée par un couple d’enzymes, la O-GlcNAc transférase (OGT) et la O-GlcNAcase (OGA). Bien que les fonctions de la O-GlcNAcylation aient été étudiées à différents niveaux de régulation cellulaire, aucune étude n’a porté jusqu’ici sur sa localisation potentielle au niveau des radeaux lipidiques (rafts). Or, il a été récemment démontré que l’élévation des niveaux de O-GlcNAcylation participait activement au phénomène de résistance à l’insuline et un nombre important de preuves a également été apporté sur le rôle critique des microdomaines lipidiques dans ce phénomène de résistance. On sait également depuis peu qu’après stimulation par l'insuline, l’OGT est recrutée à la membrane plasmique par l'intermédiaire de son domaine PPO (PIP-binding activity of OGT), et que cette relocalisation inactive la voie de signalisation PI3-kinase/Akt par antagonisme vis-à-vis de la phosphorylation. Ces trois observations suggèrent que l’OGT puisse constituer un relai essentiel permettant de transmettre l’information portée par des stimuli externes au travers de la membrane plasmique, et plus particulièrement des rafts, par le biais d’une régulation des voies de signalisation. Au cours de ma thèse, nous avons adapté une technique permettant de purifier les microdomaines lipidiques, en procédant par une extraction par le détergent CHAPSO suivi d'une étape d'ultracentrifugation. Nos expériences ont montré pour la première fois la localisation de l’OGT et de protéines O-GlcNAcylées, parmi lesquelles nous avons identifié la chaîne bêta du récepteur de l'insuline et Hsp70, au niveau des microdomaines lipidiques. Le recrutement de ces éléments est contrôlé par l’insuline: nous avons en effet observé une association progressive de la glycosyltransférase aux microdomaines lipidiques après stimulation par cette hormone. Nous avons démontré que, en réponse à l'insuline, l’OGT est recrutée au niveau des lipides rafts, ce qui suggère une régulation négative de la voie PI3-Kinase/Akt par O-GlcNAcylation, au niveau des microdomaines lipidiques. Cette étude est la première suggérant une relation directe entre la O-GlcNAcylation des protéines associées aux rafts et la régulation de la signalisation cellulaire par l'insuline. En marge de ses travaux, nous avons mis en évidence l'existence de la O-GlcNAcylation chez les deux parasites apicomplexes Toxoplasma gondii et Plasmodium falciparum. Une approche biochimique et bioinformatique a également permis de prouver l'existence propre de l'OGT chez le toxoplasme. / The attachment of O-linked beta-N-acetylglucosamine (O-GlcNAc) to proteins is a post-translational modification belonging to the group of glycosylations. This is a dynamic modification, analogous to phosphorylation, which reversibility is controlled by a couple of enzymes, namely the O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Although the functions of O-GlcNAcylation have been studied at different levels of cell regulation, until now none study refers its potential location at the level of lipids microdomains (rafts). Nevertheless, it has been recently shown an elevation of the O-GlcNAcylation levels are actively involved in the phenomenon of insulin resistance and a significant number of publications also reports the critical role of lipid microdomains in this phenomenon of resistance. Little while ago, we know that after stimulation with insulin, the OGT is recruited to the plasma membrane through its PPO domain (PIP-binding activity of OGT), and that this relocation inactivates the PI3-kinase/Akt signaling pathway by exerting an antagonistic effect on its phosphorylation. These three observations suggest that OGT may play an essential role in signal transmission through its interaction with the plasma membrane and more particularly with the lipid microdomains. During my thesis, we first adapted a technique to purify lipid microdomains, using a method combining an extraction with the detergent CHAPSO followed by an ultracentrifugation. Our experiments show for the first time that OGT and some O-GlcNAcylated proteins, among which we identified the insulin receptor beta-chain and Hsp70, are located in lipid rafts. The recruitment of these elements is controlled by insulin: we indeed observed a progressive association of the glycosyltransferase to the lipid microdomains after stimulation by this hormone. We demonstrated that in response to insuline, the OGT is recruited to lipid rafts, suggesting a down-regulation of the PI3-Kinase/Akt pathway by O-GlcNAcylation at the level of the lipid microdomains. This study is the very first suggesting a direct relationship between the O-GlcNAcylation of the lipid rafts-associated proteins and the regulation of cell signaling by insulin. In margin of these works, we have brought to the fore O-GlcNAcylation in the two apicomplexan parasites Toxoplasma gondii and Plasmodium falciparum. A biochemical and bioinformatic study led us to prove that toxoplasma possesses its own OGT.
28

Conséquences d’une perturbation de l’expérience sensorimotrice sur la plasticité synaptique du cortex cérébral : implication de deux modifications post-traductionnelles, la phosphorylation et la O-GlcNAcylation / Consequences of sensorimotor perturbation on synaptic plasticity of the cerebral cortex : involvement of two post-translational modifications, phosphorylation and O-GlcNAcylation

Fourneau, Julie 15 October 2018 (has links)
La sédentarité ou un alitement prolongé sont des situations ayant en commun une perturbation sensorimotrice (PSM), conduisant à une dégradation de la posture et la locomotion, dont l’origine est à la fois musculaire et nerveuse. Des études réalisées sur un modèle animal de PSM ont notamment montré des modifications biochimiques et morphologiques au niveau du cortex sensorimoteur. Cependant, les mécanismes sous-jacents ne sont tous pas élucidés. La O-GlcNAcylation, une glycosylation atypique, est une bonne candidate pour participer à cette neuroplasticité. Par interaction avec la phosphorylation, ces modifications post-traductionnelles sont impliquées dans des processus essentiels tels que l'activité synaptique ou la morphogenèse neuronale. L’objectif principal de cette thèse a été d’étudier les mécanismes moléculaires de la plasticité synaptique du cortex sensorimoteur et d’examiner l’implication potentielle de la O-GlcNAcylation au cours d’une période de PSM. Des changements d’activation et d’expression de protéines synaptiques ont été mis en évidence, montrant une diminution de la libération des neurotransmetteurs et une réduction de l’efficacité synaptique. La O-GlcNAcylation et la phosphorylation interviennent dans ces modifications en régulant finement l’activité de protéines spécifiques. La modulation des taux corticaux de O-GlcNAcylation permet de prévenir la réorganisation du cortex somesthésique, et prévient partiellement certaines altérations des performances sensorimotrices induite par une PSM. En conclusion, ces travaux montrent que la O-GlcNAcylation, en interaction avec la phosphorylation, participe activement à la plasticité synaptique induite par une PSM. / Sensorimotor perturbation (SMP) is frequently encountered in various situations, such as a sedentary lifestyle or prolonged bed rest. They all lead to postural and locomotor issues; whose origin is both muscular and nervous. Studies performed in a SMP animal model have shown changes in the sensorimotor cortex such as biochemical changes, somatotopic maps reorganization, morphological modifications of dendritic spines…. However, the underlying mechanisms are still unclear. O-GlcNAcylation, an atypical glycosylation, is a good candidate to participate in this neuroplasticity. By interplays with phosphorylation, these posttranslational modifications are both involved in essential cellular and physiological processes such as synaptic activity or neuronal morphogenesis. The main objective of this thesis was to study the molecular mechanisms of synaptic plasticity of the sensorimotor cortex and to examine the potential involvement of O-GlcNAcylation during a SMP period. We have shown that a period of SMP induces changes in activation and expression of synaptic proteins, leading to a decrease of neurotransmitters release and synaptic efficacy reduction. O-GlcNAcylation and phosphorylation appear to be involved in this synaptic plasticity by finely regulating the activity of specific synaptic proteins. Cortical modulation of O-GlcNAcylation level prevents somatosensory cortex reorganization, and prevents partially some alterations of sensorimotor performances induced by a SMP. In conclusion, all of these studies suggest that O-GlcNAcylation, in interaction with phosphorylation, participates actively in synaptic plasticity induced by SMP period.
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Avalia??o no ensino interdisciplinar de ci?ncias sob a perpectiva discente

Santos, Rosim?ri dos 15 March 2006 (has links)
Made available in DSpace on 2015-04-14T14:12:45Z (GMT). No. of bitstreams: 1 345650.pdf: 1125004 bytes, checksum: ec47f7b17472e427db7f3fdbf40308eb (MD5) Previous issue date: 2006-03-15 / O objetivo desta disserta??o foi pesquisar a percep??o do aluno das disciplinas de Ci?ncias sobre o processo de avalia??o da aprendizagem. Investigou-se o tipo de envolvimento do aluno na avalia??o. A investiga??o foi realizada com alunos e professores da terceira s?rie do Ensino M?dio de uma escola p?blica de Porto Alegre. O foco do trabalho foi a an?lise dos aspectos que envolvem a participa??o do estudante na constru??o do processo de avalia??o em atividades interdisciplinares. Os pressupostos da pesquisa relacionam-se ? avalia??o da aprendizagem, ? investiga??o necess?ria para uma avalia??o qualitativa e participativa, ?s quest?es ?ticas vinculadas ?s rela??es de poder, autoridade e autonomia, aos valores entre educando e educador e tend?ncias para os novos caminhos da avalia??o a serem implementadas pela escola neste novo s?culo, ? renova??o do ensino de Ci?ncias e ?s concep??es que influenciam os novos curr?culos escolares. A metodologia proposta envolveu a reda??o de depoimentos pelos alunos sobre o processo de avalia??o realizado pelos professores. A partir da an?lise de conte?do dos textos foram selecionados dez alunos para entrevista, com objetivo de esclarecer quest?es surgidas na an?lise dos depoimentos. O estudo apresenta evid?ncias de que os professores est?o promovendo mudan?as no processo de ensino e aprendizagem e, conseq?entemente, na avalia??o. ? feita uma escuta atenta ao estudante sobre o qu? e como ele aprende, a partir do momento em que se envolve na execu??o de uma proposta de trabalho, que precisa ser coerente com os seus interesses e suas necessidades.
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A trajet?ria de aprendizagem no ensino superior : percep??es de acad?micos

Mattos, Airton Pozo de 28 February 2005 (has links)
Made available in DSpace on 2015-04-14T14:22:46Z (GMT). No. of bitstreams: 1 408572.pdf: 1250524 bytes, checksum: 9d9d35947f6de6f41854b6d870d10a69 (MD5) Previous issue date: 2005-02-28 / O objetivo desta investiga??o foi o de compreender como os acad?micos percebem os processos cognitivos que ocorrem quando s?o envolvidos em experi?ncias de aprendizagem, e que outras dimens?es est?o presentes nesses processos. Ouvir os envolvidos diretamente em experi?ncias de aprendizagem para saber que dimens?es eles acreditam estar presentes neste processo foi, sem d?vida, o elemento fundamental nesta investiga??o. Afirma-se ser de grande relev?ncia saber como os acad?micos pensam que a aprendizagem ocorre, j? que s?o eles que realizam esse processo. Considerando o problema e os objetivos do estudo, optou-se por desenvolver uma investiga??o de cunho qualitativo-interpretativo. Sem d?vida, compreender o processo de aprendizagem na ?tica e nas viv?ncias dos acad?micos, tendo em vista as suas constru??es, possibilita novas reflex?es educacionais. Esses processos envolvem componentes biopsicossociais, o complexo de intera??es com o meio ambiente no contexto hist?rico. Os participantes do estudo foram 12 acad?micos de Institui??es de Ensino Superior do Rio Grande do Sul, pertencentes aos cursos: Direito, Medicina, Fisioterapia, Fonoaudiologia, Psicologia, F?sica, Biologia, Qu?mica, Pedagogia, Farm?cia, Enfermagem. Utilizou-se como instrumento de coleta de dados uma entrevista semi-estruturada que foi estudada atrav?s da an?lise de conte?do. Os resultados apontaram para as seguintes categorias: os processos cognitivos evidenciados, as etapas em que ocorrem esses processos, as experi?ncias 10 acad?micas relevantes e as condi??es necess?rias para que os processos possam gerar aprendizagem. Os processos cognitivos s?o eventos mentais que formam redes de intera??es intersubjetivas, internalizadas e externalizadas, ? medida que se instaura um processo desencadeador via est?mulo emocionalmente competente(EEC). As percep??es vieram ao encontro do que prop?e a literatura consultada, de que diferentes n?veis de hierarquia sensorial e de diferentes sentidos podem modificar os mapas cognitivos ao longo da vida. Para tanto, ? de extrema import?ncia que o professor promova experi?ncias de aprendizagem motivadoras, eliciando a rede processual que interage e ativa zonas de desenvolvimento proximal. Isso revela a necessidade de que o professor planeje melhor as atividades de aprendizagem, levando em considera??o o desenvolvimento das capacidades cognitivas, afetivas, a rela??o com o meio e a constru??o individual.

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