• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 209
  • 127
  • 83
  • 58
  • 39
  • 21
  • 9
  • 8
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 2
  • Tagged with
  • 621
  • 42
  • 38
  • 34
  • 33
  • 32
  • 29
  • 28
  • 28
  • 28
  • 27
  • 27
  • 26
  • 25
  • 25
  • 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.
71

Método para aplicação da metodologia Best Estimate Plus Uncertainty (BEPU) em um Relatório Final de Análise de Segurança (RFAS) de uma planta genérica / Application method of Best Estimate Plus Uncertainty (BEPU) methodology in a Final Safety Analysis Report (FSAR) of a generic plant

Menzel, Francine 29 August 2018 (has links)
O licenciamento de uma instalação nuclear é motivado pela necessidade de proteger os seres humanos e o meio ambiente das radiações ionizantes e, ao mesmo tempo, define as bases para a concepção e a determinação da aceitabilidade da planta. Uma parte importante no processo de licenciamento é a realização de uma análise de acidentes, a qual deve estar documentada no Relatório Final de Análise de Segurança (RFAS). Existem diferentes opções de cálculo na área de acidentes, combinando a utilização de códigos computacionais e dados de entrada, para fins de licenciamento. Uma delas é a Best Estimate Plus Uncertainty (BEPU), que considera dados de entrada realistas e as incertezas associadas. As aplicações de abordagens BEPU em processos de licenciamento iniciaram-se nos anos 2000, primeiro para análise de Acidente de Perda de Refrigerante (Loss of Coolant Accident - LOCA), e depois para a análise de acidentes como um todo, documentados no Capítulo 15 do RFAS. O presente trabalho tem como objetivo principal demonstrar que é possível a aplicação da metodologia BEPU em todas as análises contidas no RFAS, identificando as disciplinas-chave do processo de licenciamento e os códigos computacionais utilizados. Este trabalho foi desenvolvido em conjunto com a Universidade de Pisa, Itália, com a colaboração do Prof. Dr. Francesco D\'Áuria. A principal motivação desse trabalho é o aprimoramento da metodologia BEPU para sua implementação em reatores do tipo PWR (Pressurized Water Reactor) no Brasil e no mundo, especialmente para fins de licenciamento, uma vez que as plantas nucleares brasileiras têm pouca experiência na área de cálculo de incertezas. / The licensing process of a nuclear power plant is motivated by the need to protect humans and the environment from ionizing radiation and, at the same time, sets out the basis for the design and determining the acceptability of the plant. An important part of the licensing process is the realization of accident analysis, which should be documented in the Final Safety Analysis Report (FSAR). There are different options on accidents calculation area by combining the use of computer codes and data entry for licensing purposes. One is the Best Estimate Plus Uncertainty (BEPU), which considers realistic input data and associated uncertainties. Applications of BEPU approaches in licensing procedures were initiated in the 2000s, first to analysis of Loss of Coolant Accident (LOCA), and then to the accident analysis as a whole, documented in Chapter 15 of the FSAR. This work has as main objective demonstrate the implementation of BEPU methodology in all analyses contained in FSAR is possible, identifying the key disciplines of the licensing process and the computer codes. This work was done in conjunction with the University of Pisa, Italy, with the collaboration of Professor Francesco D\'Auria. The main motivation of this work is the improvement of BEPU methodology for its implementation in PWR (Pressurized Water Reactor) reactors in Brazil and the world, especially for licensing purposes, since the Brazilian nuclear plants have little experience in the regulatory area, and specifically in calculation uncertainties.
72

Traditions céramiques au Néolithique récent et final dans le Centre-Ouest de la France (3700-2200 avant J.-C.) : filiations et interactions entre groupes culturels / Ceramic traditions in the Late and Final Neolithic in Central-West France (3700-2200 BC) : affiliations and interactions between cultural groups

Ard, Vincent 24 October 2011 (has links)
Deux millénaires après l’arrivée des premiers colons néolithiques, le Centre-Ouest de la France voit l’émergence au Néolithique récent d’une « mosaïque » de groupes culturels, peu après 3700 avant J.-C. À l’exception de la culture saintongeaise peu-richardienne, réputée pour ses céramiques aux décorations singulières et parfois exubérantes, tous ces groupes produisent des céramiques de facture grossière et peu décorée, difficilement distinguables sur les seuls critères morpho-stylistiques. Or ce sont ces critères qui sont généralement employés pour la définition des cultures néolithiques. L’origine et la caractérisation précise de ces groupes du Néolithique récent sont donc couramment discutées, tout comme leur filiation avec la culture artenacienne qui les succède au Néolithique final.Afin de préciser ce cadre chrono-culturel et d’appréhender les filiations et interactions entre groupes du Néolithique récent et final (3700-2200 avant J.-C.), notre étude a analysé l’ensemble de la chaine opératoire de fabrication de leurs céramiques à partir de vingt-trois assemblages issus de sites domestiques (enceintes fossoyées) et funéraires répartis sur l’ensemble du Centre-Ouest, entre Loire et Dordogne. L’objectif de ce travail est de mettre en évidence des « manières de faire » transmisses au sein des groupes de producteurs, comme l’ont montré de multiples études ethnoarchéologiques. Huit traditions céramiques ont été mises en évidence et caractérisées par les méthodes de façonnage employées puis le matériau argileux et enfin les formes produites. Elles sont présentées successivement en illustrant chacune des macrotraces les plus caractéristiques par des macro-photos. Les distributions chronologiques et spatiales de chacune de ces traditions sont ensuite discutées afin de tester la validité du cadre chrono-culturel actuel. La mise en évidence de trois aires culturelles distinctes, dans la seconde moitié du Néolithique récent (Seuil du Poitou, Taizé et Peu-Richard), nous permet ensuite de discuter de leurs origines respectives et des interactions entre elles. On remarque l’émergence d’une culture dominante peu-richardienne, peut-être à la faveur du contrôle de l’exploitation du sel dans les marais poitevin et de Rochefort. Ses productions céramiques, parfois diffusées à longue distance, sont à l’origine de celles de la culture artenacienne dont l’aire d’influence dépasse largement les frontières du Centre-Ouest au Néolithique final (2900-2200 avant J.-C. environ). / Two millennia after the arrival of the first Neolithic settlers, a “mosaic” of cultural groups appeared in Central-West France in the Late Neolithic period, c. 3700 BC. Except for the famous Peu-Richard culture of Saintonge, known for its ceramic decorations which are sometimes exuberant, all the groups of this cultural mosaic produce coarse and sparsely decorated ceramics, which are now difficult to distinguish just on morpho-stylistic criteria. However, these morphological criteria are commonly used for the definition of the Neolithic cultures. The origin and precise characterization of these Late Neolithic groups, and also their affiliation with the Artenac culture of the Final Neolithic period, are commonly discussed.To clarify this chrono-cultural context and understand the affiliations and interactions between groups of the Late and Final Neolithic (c. 3700-2200 BC), our study analyzes all the “chaine opératoire” of pottery manufacture from twenty-three ceramic assemblages from domestic (causewayed enclosures) and funeral sites which are distributed throughout the Central-West France, between Loire and Dordogne rivers. The aim of this work is to highlight the “ways of doing” transmitted in potters groups, as shown by multiple ethnoarchaeological studies. Eight ceramic traditions, characterized by the shaping methods, the clay material and finally the forms produced, are all successively presented and the most characteristic features of each ones are illustrated by macro-photos.Therefore, the chronological and spatial distributions of these ceramic traditions are discussed in order to test the validity of the current chrono-cultural context. Three cultural areas are identified in the second half of the Late Neolithic (Seuil du Poitou, Taizé and Peu-Richard) which offer the possibility to discuss their respective origins and the interactions between these areas. The emergence of a dominant culture (Peu-Richard) is observed and his power is perhaps related to the control of the salt exploitation in the poitevin and Rochefort marshes. The Peu-Richard ceramic productions, sometimes found at long-distance, are the ancestors of those of the Artenac culture whose area of influence extends beyond the Central-West borders in the Late Neolithic (c. 2900-2200 BC).
73

La gestion des sépultures collectives du bassin parisien à la fin du néolithique / The using strategy of the collective burials in Paris basin at the end of the neolithic

Blin, Arnaud 09 December 2011 (has links)
Depuis près d’un siècle et demi, près de quatre cent cinquante sépultures collectives ont été découvertes dans le Bassin parisien. L’information archéologique à disposition y est largement lacunaire. La connaissance des groupes chrono-culturels de la fin du Néolithique a tout de même été enrichie grâce au mobilier funéraire. Il a permis de définir une phase de construction et d’utilisation commune pour une grande majorité de sépultures collectives au Néolithique récent 2 (3350-3000 av. J.-C). Une minorité d’entre elles a été utilisée au Néolithique final 1 (2900-2550 av. J.-C.), voire jusqu’au début de l’Âge du Bronze. Malgré un horizon chronologique commun, les sépultures collectives du Bassin parisien présentent une étonnante diversité architecturale. Deux grands types de monuments ont été identifiés : les allées sépulcrales et les hypogées. Ils coexistent avec un ensemble de sépulcres anciennement appelés « dolmens » ou « sépultures en fosse », deux termes qui sont aujourd’hui à bannir. Chaque type architectural se caractérise par des techniques de construction, une répartition géographique, une logique d’implantation, une durée d’utilisation et une concentration de mobilier qui lui est propre. Cette diversité est-elle renforcée par des divergences au niveau des pratiques funéraires ? Les différents types de sépultures collectives du Bassin parisien se distinguent-ils également par leurs modes de fonctionnement ? Peuvent-ils constituer des caractères culturels originaux ? / For one century and an half, around four hundred and fifty collective burials had been discovered in the Paris basin. The archeological information is widely lacunar. The knowledge of the chronological and cultural groups of the end of the Neolithic had been enhanced thanks to the burial deposit. It permitted to define a common phase of building and use of a large majority of the collective burials during the recent Neolithic (3350-3000 av. J.-C). A minority of them had been used during the final Neolithic(2900-2550 av. J.-C.), or even till the beginning of the Bronze Age.In spite of a common chronological horizon, the collective burials of the Paris basin presents a suprising architectural diversity. Two main types of monuments had been identified : the sepulchral galleries and the hypogeums. They coexist with a group of burials formerly named “dolmen” or “burial grave”, two names that we could not use any more. Each archictectural type is characterised by his own building technique, geographical distribution, implantation logic, useful life and deposit concentration. Is this diversity reinforced by some differences on burial practices ? Are the different types of collective burials of the Paris basin distinguished between as well by their functioning ? Could they constitue original characteristic cultural ?
74

Método para aplicação da metodologia Best Estimate Plus Uncertainty (BEPU) em um Relatório Final de Análise de Segurança (RFAS) de uma planta genérica / Application method of Best Estimate Plus Uncertainty (BEPU) methodology in a Final Safety Analysis Report (FSAR) of a generic plant

Francine Menzel 29 August 2018 (has links)
O licenciamento de uma instalação nuclear é motivado pela necessidade de proteger os seres humanos e o meio ambiente das radiações ionizantes e, ao mesmo tempo, define as bases para a concepção e a determinação da aceitabilidade da planta. Uma parte importante no processo de licenciamento é a realização de uma análise de acidentes, a qual deve estar documentada no Relatório Final de Análise de Segurança (RFAS). Existem diferentes opções de cálculo na área de acidentes, combinando a utilização de códigos computacionais e dados de entrada, para fins de licenciamento. Uma delas é a Best Estimate Plus Uncertainty (BEPU), que considera dados de entrada realistas e as incertezas associadas. As aplicações de abordagens BEPU em processos de licenciamento iniciaram-se nos anos 2000, primeiro para análise de Acidente de Perda de Refrigerante (Loss of Coolant Accident - LOCA), e depois para a análise de acidentes como um todo, documentados no Capítulo 15 do RFAS. O presente trabalho tem como objetivo principal demonstrar que é possível a aplicação da metodologia BEPU em todas as análises contidas no RFAS, identificando as disciplinas-chave do processo de licenciamento e os códigos computacionais utilizados. Este trabalho foi desenvolvido em conjunto com a Universidade de Pisa, Itália, com a colaboração do Prof. Dr. Francesco D\'Áuria. A principal motivação desse trabalho é o aprimoramento da metodologia BEPU para sua implementação em reatores do tipo PWR (Pressurized Water Reactor) no Brasil e no mundo, especialmente para fins de licenciamento, uma vez que as plantas nucleares brasileiras têm pouca experiência na área de cálculo de incertezas. / The licensing process of a nuclear power plant is motivated by the need to protect humans and the environment from ionizing radiation and, at the same time, sets out the basis for the design and determining the acceptability of the plant. An important part of the licensing process is the realization of accident analysis, which should be documented in the Final Safety Analysis Report (FSAR). There are different options on accidents calculation area by combining the use of computer codes and data entry for licensing purposes. One is the Best Estimate Plus Uncertainty (BEPU), which considers realistic input data and associated uncertainties. Applications of BEPU approaches in licensing procedures were initiated in the 2000s, first to analysis of Loss of Coolant Accident (LOCA), and then to the accident analysis as a whole, documented in Chapter 15 of the FSAR. This work has as main objective demonstrate the implementation of BEPU methodology in all analyses contained in FSAR is possible, identifying the key disciplines of the licensing process and the computer codes. This work was done in conjunction with the University of Pisa, Italy, with the collaboration of Professor Francesco D\'Auria. The main motivation of this work is the improvement of BEPU methodology for its implementation in PWR (Pressurized Water Reactor) reactors in Brazil and the world, especially for licensing purposes, since the Brazilian nuclear plants have little experience in the regulatory area, and specifically in calculation uncertainties.
75

“Gosta dessa baiana?” Crioulas e outras baianas nos cartões postais de Lindemann (1880-1920)

Santos, Isis Freitas dos January 2014 (has links)
Submitted by PPGH null (poshisto@ufba.br) on 2017-06-26T14:25:28Z No. of bitstreams: 1 Dissertação - Final isis.pdf: 4044723 bytes, checksum: e53228283c0a20715e825059a80b3a43 (MD5) / Approved for entry into archive by Uillis de Assis Santos (uillis.assis@ufba.br) on 2017-06-29T11:51:42Z (GMT) No. of bitstreams: 1 Dissertação - Final isis.pdf: 4044723 bytes, checksum: e53228283c0a20715e825059a80b3a43 (MD5) / Made available in DSpace on 2017-06-29T11:51:43Z (GMT). No. of bitstreams: 1 Dissertação - Final isis.pdf: 4044723 bytes, checksum: e53228283c0a20715e825059a80b3a43 (MD5) / CNPq / Esta pesquisa tem por objetivo investigar o processo de construção da imagem da mulher de cor da Bahia em símbolo local nas últimas décadas do século XIX e iniciais do XX. Esta construção não se realiza de maneira unilateral e sem conflitos. Tendo como objetos de pesquisa as construções imagéticas que falam das identidades destas mulheres e que circularam em postais, fotografias e discursos literários, procuro analisar as dinâmicas que envolvem a produção, circulação e leituras possíveis destes objetos com o intuito de perceber as dinâmicas sociais que o norteia. Para guiar a primeira parte do trabalho trago a trajetória, na Bahia, do fotógrafo Rodolpho Lindemann autor e divulgador de duas séries de postais que trazem as mulheres de cor da Bahia como tema; a interação entre fotógrafos e modelos nas ruas e nos estúdios de Salvador e as dinâmicas que envolveram a autorrepresentação. Por fim procuro discutir esta mesma construção sob o ponto de vista da interação entre as classes dominantes de Salvador com as mulheres de cor que trabalhavam em seus lares. O lar branco torna-se local de construção de uma memória que acaba por produzir as “baianinhas”, símbolo ressignificado de uma cultura local.
76

Avaliação da influência da temperatura e ponto de orvalho no recozimento final de aços elétricos semiprocessados e totalmente processados / Evaluation of the influence of final annealing heat treatment temperature and dew point in semi-processed and fully processed electrical steels

Alexandre, édina Serpa 07 December 2010 (has links)
Made available in DSpace on 2016-12-08T17:19:37Z (GMT). No. of bitstreams: 1 Resumo.pdf: 10956 bytes, checksum: b3ab8ff2ededda1434fbc70325d132f4 (MD5) Previous issue date: 2010-12-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Semi-processed electrical steels require annealing after processing in the motors manufactures to improve motors efficiency by reducing losses and increasing permeability. Annealing in fully processed electrical steel is performed to relax the residual stress and promote recovery or recrystallization of distorted parts. Commercial samples from different steels with different chemical compositions were selected to evaluate the influence of final annealing heat treatment temperature and dew point on the magnetic properties, the carbon content and grain size increase. Were performed with annealing atmosphere without steam and with dew point of 5, 10, 20 and 25°C at temperatures of 760 and 790°C. Magnetic losses, relative permeability, carbon content, grain size and mechanical properties measurements were made in addition to the evaluation of the microstructure to determine this influence. It was observed in the semi-processed steel with 300 ppm carbon content, which with dew point increase the carbon content reduce the grain size increase and improve magnetic properties. In the other steels studied, reducing the dew point improved the magnetic properties, but the atmosphere without steam has improved only fully processed steel with 2% silicon. It was found that in fully processed steels the best results were obtained with annealing temperature of 790°C. / Aços elétricos semiprocessados necessitam de recozimento após a sua manufatura para melhorar o rendimento dos motores com a redução das perdas magnéticas e aumento da permeabilidade. os aços totalmente processados o recozimento é realizado para relaxar as tensões residuais e promover a recuperação ou recristalização das partes deformadas. Amostras comerciais de diferentes aços com variadas composições químicas foram selecionadas para avaliar a influência do ponto de orvalho e temperatura de recozimento final nas propriedades magnéticas, no teor de carbono e no aumento do tamanho de grão. Foram realizados recozimentos com atmosfera sem vapor e com ponto de orvalho de 5, 10, 20 e 25°C, nas temperaturas de 760 e 790°C. Medições de perdas magnéticas, permeabilidade, teor de carbono, tamanho de grão e propriedades mecânicas, além da avaliação da microestrutura, foram efetuados para determinar esta influência. Foi verificado no aço com 300 ppm de carbono, que com aumento do ponto de orvalho reduziu o teor de carbono, aumentou o tamanho de grão e melhorou as propriedades magnéticas. Nos demais aços estudados, a redução do ponto de orvalho melhorou as propriedades magnéticas, porém com ausência de umidade somente houve melhora no aço totalmente processado com 2% de silício. Foi verificado ainda que nos aços totalmente processados os melhores resultados foram obtidos com a temperatura de recozimento de 790°C.
77

Domino Effect or Butterfly Effect? The (distorted) concept of protected consumer in Peruvian law / ¿Efecto dominó o efecto mariposa? El (distorsionado) concepto de consumidor protegido en el derecho peruano

Cavero Safra, Enrique 12 April 2018 (has links)
In this article, the author tell us regarding the main function of the consumer protection system, which is to maximize the making good decisions consumption by consumers. Likewise, he tells us about the  information asymmetry and how it should be considered, as well as the inequality between a consumer and a seller. To end, he points out the discussion of whom and why would be considered as consumers as well as the effects of this decision. / En el presente artículo, el autor nos habla sobre la principal función del sistema de protección al consumidor, que es la de maximizar la toma de buenas decisiones de consumo por parte de los consumidores. Asimismo, el autor nos habla acerca de la asimetría de la información y cómo debe ser tomada en cuenta, así como de la desigualdad entre un consumidor y un vendedor. Finalmente, plantea la discusión acerca de quiénes y por qué deben ser considerados como consumidores así como los efectos de esta decisión.
78

El reino de Cuismancu: orígenes y transformación en el Tawantinsuyu

Watanabe, Shinya 10 April 2018 (has links)
The Cuismanco Kingdom: Origins and Transformation in the TawantinsuyuThis paper presents the data of excavation data from Tantarica site, in the northern highland of Peru, also examines the extent interpretations about the Cuismancu Kingdom based on the documents. Up to now the opinion prevents that the Cuismancu Kingdom existed before the arrival of the Incas and was incorporated into the Inca dominion. This interpretation contradicts the archaeological data. The material culture of Tantarica is closer to the north coast than with the Cajamarca Basin, which indicates heterogeneity within the domain of the Cuismancu Kingdom. Thus, it is probable that the political unit as seven warangas of the Cuismancu Kingdom was formed under the Inca domain and is not of preincaic origin. / En este artículo se presentan los resultados de excavaciones llevadas a cabo en el sitio arqueológico de Tantarica, ubicado en la sierra norte del Perú, y se revisa interpretaciones sobre el reino de Cuismancu sobre la base de los documentos. Hasta la fecha se mantiene la imagen de un reino de Cuismancu que existió antes de la llegada de los incas y que se incorporó bajo su dominio. Sin embargo, esta interpretación no concuerda con los datos arqueológicos. Los materiales arqueológicos de Tantarica presentan una relación más estrecha con la costa norte que con el valle de Cajamarca, indicando que existe más bien una heterogeneidad dentro de dicho reino. Por ello, es razonable pensar que la unidad política del reino de Cuismancu en forma de siete warangas se formó bajo el dominio incaico y que no se remonta al periodo inmediatamente anterior.
79

Fisiologia molecular digestiva da larva de Musca domestica / Digestive molecular physiology of Musca domestica larvae

André Coppe Pimentel 21 November 2011 (has links)
A digestão nos insetos ocorre no intestino médio de forma compartimentada. A digestão inicial dos polímeros ocorre no interior da membrana peritrófica. Os oligômeros resultantes difundem-se para o espaço luminal exterior à membrana peritrófica onde são atacados por outras enzimas. Na digestão final os dímeros resultantes são hidrolisados por enzimas imobilizadas na superfície do epitélio do intestino médio. Após o processo de digestão final os monômeros são absorvidos pelas células do epitélio intestinal. Os Díptera ditos superiores, incluindo a mosca doméstica, apresentam peculiaridades digestivas que aparentemente resultam de adaptações para digerir uma dieta que consiste principalmente de bactérias. No ventrículo anterior ocorre uma diminuição no conteúdo de amido do bolo alimentar. Na porção seguinte, o bolo alimentar passa para o ventrículo médio onde as bactérias são mortas pela ação combinada de baixo pH, uma lisozima digestiva e uma proteinase tipo catepsina D. O material liberado das bactérias é digerido no ventrículo posterior, como ocorre no ventrículo inteiro da maioria dos insetos de outros grupos taxonômicos. Com o objetivo de compreender a peculiar digestão em Musca domestica, foram utilizadas suas larvas para identificar funcionalmente as regiões absortivas de nutrientes, identificar as moléculas envolvidas na absorção de nutrientes, identificar as moléculas envolvidas com tamponamento e fluxos de fluidos intestinais, sequenciar as enzimas digestivas principais e identificar os seus sítios de secreção. Experimentos fisiológicos de absorção de glicose e análises de atividade enzimática permitiram acessar de maneira direta os aspectos da digestão. Contudo, experimentos de sequenciamento de bibliotecas de cDNA, análise de sequências transcritas e verificação de expressão de genes em diferentes tecidos foram abordagens fundamentais na identificação das moléculas subjacentes aos processos fisiológicos intestinas de Musca domestica. Os indícios de que absorção de glicose no intestino de Musca domestica se dê por transportadores do tipo SGLT, com a possível participação de facilitadores do tipo GLUT, permitem estabelecer um foco para futuros estudos. A descrição de sequências relacionadas ao tamponamento intestinal permitiu ampliar a discussão sobre tal processo. Ao detalhar os sítios de expressão da subunidade a da V-ATPase, do canal de cloreto e do transportador de amônia foi possível testar o modelo de tamponamento proposto anteriormente e propor a participação de outras moléculas no processo. Sequências correspondentes as atividades de carboxipeptidase, maltase e aminopeptidase descritas na literatura foram pesquisadas, gerando sequências candidatas a codificarem as referidas enzimas. Com isso, é possível descrever a digestão de oligômeros e dímeros com base nos genes transcritos e nas sequências de aminoácidos que formam as enzimas digestivas. A descoberta da sequência que transcreve uma metaloproteinase, por sua vez, abre caminhos para a descrição e caracterização de sua atividade proteolítica nos tecidos digestivos da larva de Musca domestica. Essa análise permitiu também elucidar a localização dos sítios de expressão e, portanto, as zonas de secreção de enzimas. De maneira geral, este estudo contribuiu para a compreensão de diversos aspectos da digestão de Musca domestica, elucidando questões da particular fisiologia digestiva desse inseto. / Digestion in insects occurs in the midgut in a compartmentalized way. Initial digestion takes place inside the peritrophic membrane. The resulting oligomers diffuse into the luminal space outside the peritrophic membrane where they are hydrolyzed by other enzymes. In the final digestion, the resulting dimers are hydrolyzed by enzymes immobilized on the midgut epithelium. After the final digestion, the monomers are absorbed by intestinal epithelial cells. The so-called higher Diptera, including the house fly, have digestive peculiarities apparently resulting of adaptations to digest a diet consisting mainly of bacteria. In the anterior midgut there is a decrease in the starch content of the food bolus. The bolus now passes into the middle midgut, where bacteria are killed by the combined action of low pH, a special lysozyme and a cathepsin D-like proteinase. Finally, the material released by bacteria is digested in the posterior midgut, as is observed in the whole midgut of insects of other taxa. In order to understand the peculiar digestion in Musca domestica, the larvae were used to identify (a) the functionally the nutrient absorptive regions, (b) the molecules involved in the absorption of nutrients, (c) the molecules involved in buffering and fluid flows, (d) the cDNA sequences corresponding to intestinal digestive enzymes, (e) the main sites of secretion. Physiological experiments of glucose absorption and enzyme activity analysis allowed a direct access to aspects of digestion. Otherwise, cDNA library sequencing followed by sequence annotation and tissue-specific expression analysis were fundamental approaches in the understanding of intestinal physiology of Musca domestica. Evidence that glucose absorption in the gut of Musca domestica occurs through SGLT-like transporters, with the possible participation of facilitators GLUT-like, allowed us to establish a focus for future studies. The description of cDNA sequences corresponding to proteins putatively responsible for intestinal buffering widened the discussion of this process. The finding of the expression sites of V-ATPase subunits, chloride channel, and ammonia transporter led to revising the present buffering model and the inclusion of other molecules in the process. The cDNA sequences corresponding to the activities of carboxypeptidase, aminopeptidase and maltase described in the literature were searched for as candidate sequences to encode those enzymes. This made it possible to describe the digestion of oligomers and dimers based on transcribed genes and enzyme amino acid sequences. The discovery of the metalloproteinase transcribing sequence opened a new research line: the description and characterization of its proteolytic activity in the midgut of the Musca domestica larvae. This study also allowed elucidating the location of digestive enzyme expression sites and, therefore, the putative zones of enzyme secretion. Overall, this study contributed to understanding many aspects of digestion of Musca domestica, clarifying aspects of the peculiar digestive physiology of this insect.
80

Evidentiality, Epistemic Modality and Mirativity: The Case of Cantonese Utterance Particles Ge3, Laak3, and Lo1

Law, Ka Fai 02 June 2020 (has links)
This thesis examines a set of three utterance particles—ge3, laak3, and lo1—in Hong Kong Cantonese in terms of evidentiality, epistemic modality, and mirativity. Cantonese utterance particles have long been studied; however, close investigation of evidentiality and mirativity on a small set of particles is relatively rare. Previous accounts claim that ge3 and laak3 convey certainty. On the other hand, linguists also claim that the use of the utterance particle lo1 assumes a high level of knowledge from a hearer. This thesis has two main purposes: to untangle the differences between the utterance particles ge3 and laak3 in terms of epistemic modality and evidentiality and to reveal the mirative meanings of the utterance particle lo1. I postulate that the utterance particle ge3 conveys both epistemic modality and evidentiality. For epistemic modality, ge3 concerns a speaker’s knowledge. The evidential meaning—access to prior knowledge—is realized through implicature. This pragmatic reading is highly context dependent. In contrast, the utterance particle laak3 conveys only epistemic modality which concerns a state of affairs and signifies a change of state. Lastly, this study also reveals that the utterance particle lo1 has mirative values of sudden realization and counterexpectation under certain conversational contexts.

Page generated in 0.0685 seconds