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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.
1

A raridade de especies arboreas na floresta ombrofila densa Atlantica : uma analise de metadados / The rarity of tree species in the atlantic dense ombrophilous forest : a analysis of metadata

Caiafa, Alessandra Nasser 28 February 2008 (has links)
Orientador: Fernando Roberto Martins / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T10:49:08Z (GMT). No. of bitstreams: 1 Caiafa_AlessandraNasser_D.pdf: 2168770 bytes, checksum: ff4aa656d8f25f6c55a2c4a5b03df95a (MD5) Previous issue date: 2008 / Resumo: A Floresta Ombrófila Densa Atlântica ou Mata Atlântica sensu stricto, classificada como um hotspot de biodiversidade, tem como características o grande número de espécies de baixa constância e distribuição geográfica restrita, além do alto índice de espécies endêmicas. O termo raro descreve um amplo arranjo de padrões de amplitude geográfica, preferências por habitat e tamanho populacional, que são as principais medidas para se aferir raridade. Em face dessa grande amplitude de significados, optamos por aplicar o sistema de Rabinowitz para classificar as formas de raridade de espécies arbóreas na porção meridional da Mata Atlântica s.s. Usando metadados tomados de toda a Floresta Ombrófila Densa Atlântica, nossos objetivos foram: a) avaliar o estado de nosso conhecimento fitossociológico sobre essa Região Fito-Ecológica; b) diagnosticar quais formas de raridade de Rabinowitz e suas proporções ocorrem nas espécies arbóreas da Mata Atlântica s.s.; e c) investigar se alguma forma de raridade estaria associada a alguma variável abiótica Considerando nosso presente conhecimento fitossociológico sobre espécies arbóreas da Floresta Ombrófila Densa Atlântica, levantamentos ainda são necessários, especialmente na porção nordeste. Cada levantamento deveria obedecer a um protocolo mínimo, de modo a padronizar procedimentos e permitir análises comparativas mais robustas. Além de informações relativas à própria comunidade, são indispensáveis informações adicionais, tais como as referentes à classificação da vegetação, ao clima, solo e re levo. O exame de variáveis bióticas e abióticas propicia muitas informações críticas e permite construir hipóteses e expectativas relevantes a processos biogeográficos e à conservação e recuperação de áreas degradadas. Encontramos todas as sete formas de raridade na porção meridional da Floresta Atlântica s.s.: 46% do total de 846 espécies arbóreas apresentaram distribuição ampla (espécies euritópicas) e 54%, distribuição restrita (espécies estenotópicas); 73% ocorreram em habitats variados (eurióicas) e 27%, em habitats únicos (estenóicas); 76% apresentaram pelo menos uma população localmente abundante e 24% tinham populações escassas em toda a sua amplitude geográfica. Embora haja críticas contra o sistema de Rabinowitz para classificar a raridade das espécies, sua aplicação tem muitas vantagens, especialmente em relação à sistematização de discussões e pontos de vistas intrincados e esparsos. A aplicação do sistema de Rabinowitz à Floresta Ombrófila Densa Atlântica evidenciou espécies raras de árvores, que estão ameaçadas devido à sua distribuição geográfica restrita, a seus habitats únicos e a suas populações escassas. Não encontramos nenhuma variável abiótica especificamente associada a qualquer forma de raridade. Esses resultados indicam que cada forma de raridade resulta de ações sinérgicas complexas entre variáveis bióticas e abióticas / Abstract: The Dense Ombrophilous Atlantic Forest (or Atlantic Coastal Forest sensu stricto) is classified as a biodiversity ¿hot-spot¿ and has a very large number of species of low constancy and restricted geographical distribution as well as a very high number of endemic species. The term ¿rare¿ has been used to describe a wide range of patterns of geographical amplitudes, habitat preferences, and population sizes, which represent the usual measures to assess rarity. In face of this wide range of meanings, we chose to apply Rabionwitz¿s system to classify rarity forms of tree species in the south portion of the Atlantic Coastal Forest. Using metadata taken from the Dense Ombrophilous Atlantic Forest, our aims were: a) to evaluate the state of our phytosociological knowledge of this Phyto-Ecological Region; b) to highlight Rabinowitz¿s rarity forms and their proportion among tree species; and c) to investigate whether any form of rarity would be associated with an abiotic variable. Considering our present knowledge of phytosociology of tree species, surveys are still very necessary, especially in the Northeastern portion of the Dense Ombrophilous Atlantic Forest. Each survey should obey to a minimum protocol, so as to standardize procedures and allow more robust comparative analyses. Besides information concerning the plant community itself, additional information is indispensable, such as vegetation classification, climate, soil, and relief. The examination of both biotic and abiotic variables can provide much critical information and allow the elaboration of hypotheses and expectations relevant to biogeographical processes, and the conservation and remediation of degraded areas. We found all eight forms of rarity in the Atlantic Coastal Forest s.s: 46% of the total 846 tree species had wide distribution (euritopic) and 54% had restricted distribution (stenotopic); 73% occurred in varied habitats (euryecious) and 27% occurred in unique habitats (stenoecious); 76% had at least one locally abundant population and 24% had scarce populations all over their ranges. Although there are critiques towards Rabinowitz¿s rarity classification system, this way to 4 assess rarity has many advantages, especially concerning the systematization of entangled discussions and approaches. The application of Rabinowitz¿s system to the Dense Ombrophilous Atlantic Forest highlighted rare tree species, which are in danger due to their restricted range, unique habitats and scarce populations. We did not find any abiotic variable that correlated exclusively with any given form of rarity. These results indicate that each form of rarity is the result of synergic actions between complex abiotic and biotic variables / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal
2

Banco de imagens: abordagem teórica conceitual de representação de fotografias para uso na publicidade

Souza, Jóice Cleide Cardoso Ennes de 15 March 2013 (has links)
Submitted by Priscilla Araujo (priscilla@ibict.br) on 2016-10-13T19:24:46Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese-JoiceCardoso.pdf: 3135800 bytes, checksum: 1d8708703eb3a010bf4bd6f4a6d0b57e (MD5) / Made available in DSpace on 2016-10-13T19:24:46Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese-JoiceCardoso.pdf: 3135800 bytes, checksum: 1d8708703eb3a010bf4bd6f4a6d0b57e (MD5) Previous issue date: 2013-03-15 / O trabalho aborda a indexação de imagens fotográficas em bancos de imagens para publicidade, justificada pela proliferação de fotografias na atual sociedade da informação e sua divulgação rápida e online. Os bancos de imagem se apresentam como recurso para os publicitários que demandam de tempo para a criação de anúncios, pois oferecem coleções fotográficas selecionadas, com tratamento documental direcionado ao usuário. Objetiva investigar procedimentos para a representação e recuperação de fotografias arquivadas em bancos de imagens, visando obter subsídios para reflexão e desenvolvimento de esquema teórico para indexação de fotografias em arquivos digitais. A análise qualitativa foi realizada a partir da identificação de elementos na literatura sobre publicidade direcionada ao público feminino, para definição de atributos visando atender demandas de conteúdo publicitário. Selecionou-se o banco de imagens Latinstock para o desenvolvimento da análise empírica por oferecer coleções para uso publicitário, ser em português e explicitar os princípios adotados na análise conceitual das fotografias. As amostras investigadas indicam que os atributos usados pelo banco de imagem são compatíveis com a representação de aspectos subjetivos/abstratos da fotografia, e que o uso de substantivos e adjetivos na indexação atendem aos elementos identificados na literatura de publicidade. Concluiu-se que a indexação de imagens para publicidade compreende atributos técnicos, figurativos e subjetivos. / The research approaches the indexing of images in images databank for advertising, justified by the proliferation of photographs in the information society and its rapid online dissemination. Image databank are presented as a resource for advertisers that demand time for creating ads because they offer selected photographic collections with the documentary directed the user. Work aims to investigate procedures for the representation and retrieval of archived photographs in image databanks, in order to obtain subsidies for reflection and development of theoretical scheme for indexing photos into digital files. Qualitative analysis was performed based on the identification of elements in the advertising literature targeted to a female audience, to define attributes to meet the demands of advertising content. Stock photos Latinstock was selected to the empirical analysis by offering collections for advertising use, in Portuguese and explains the principles adopted in the conceptual analysis of the photographs. The samples investigated indicate that the attributes used by the image databank are compatible with the photo representation of subjective and abstracts aspects, and the use of nouns and adjectives in indexing meet the elements identified in the advertising literature. It was concluded that indexing of images for advertising comprises technical, figurative and subjective attributes.
3

Identification moléculaire et caractérisation fonctionnelle d'une nouvelle sous-famille de cytochromes P450, CYP71AZ, impliquée dans la synthèse de furanocoumarines et coumarines chez Pastinaca sativa / Molecular isolation and functional characterization of a novel cytochrome P450 subfamily, CYP71AZ, involved in the biosynthesis of furanocoumarins and coumarins in Pastinaca sativa

Krieger, Célia 16 December 2014 (has links)
Les furanocoumarines (FCs) sont des métabolites secondaires principalement synthétisés chez quatre familles botaniques et dérivent de la voie de biosynthèse des phénylpropanoïdes. Ces phytoalexines interviennent dans les processus de défense de la plante et présentent un fort potentiel thérapeutique. Des travaux réalisés dans les années 1960 sur des cultures cellulaires en parallèle de l’utilisation de précurseurs radiomarqués ont permis de démontrer que de nombreuses enzymes impliquées dans cette voie appartenaient à la famille des cytochromes P450 (P450s). Seules deux d’entre elles avaient pu être identifiées d’un point de vue moléculaire au début de ce travail de thèse. Afin de générer des informations concernant le génome de plantes productrices de FCs, nous avons fait séquencer les ARNm extraits de feuilles de Pastinaca sativa, de Ruta graveolens et de Cullen cinereum. L’analyse in silico de ces trois banques de données a permis d’identifier près de 800 fragments d’ADNc codants pour des P450s. Des travaux antérieurs réalisés au laboratoire et l’analyse comparative des transcriptomes de ces 3 plantes nous ont amenés à nous focaliser sur la sous-famille CYP71AZ au travers d’une étude fine de CYP71AZ3 et CYP71AZ4. La caractérisation fonctionnelle de ces enzymes a été réalisée dans un système d’expression hétérologue eucaryote : Saccharomyces cerevisiae. Les résultats obtenus ont permis de montrer que CYP71AZ4 avait une spécificité de substrat assez large puisqu’elle pouvait métaboliser au moins une FC et 4 coumarines. L’analyse et la comparaison des constantes cinétiques pour chacun de ces substrats indiquent néanmoins que le psoralène est le substrat préférentiel. La caractérisation fonctionnelle de CYP71AZ3 a mis en évidence que cette enzyme pouvait hydroxyler l’esculétine, une coumarine, mais ne jouait aucun rôle dans la synthèse de FCs. Ces travaux mettent en évidence la diversité fonctionnelle au sein d’une même sous-famille enzymatique et permettent d’émettre des hypothèses nouvelles quant à l’apparition de cette voie de biosynthèse chez les Apiacées d’une part, et chez les autres familles botaniques d’autre part / Furanocoumarins (FCs) are secondary metabolites mainly synthetized in four botanical families deriving from the phenylpropanoid biosynthetic pathway. These phytoalexins are involved in plant defense mechanisms and present strong therapeutic potential. Early studies in the 1960s based on cell cultures and the use of radiolabeled precursors have shown that many enzymes involved in this pathway belong to the cytochrome P450 family (P450s). Only two of them had been identified from a molecular point of view at the beginning of this thesis. In order to generate information regarding the genome of plants producing FCs, we sequenced the mRNA extracted from leaves of Pastinaca sativa, Ruta graveolens, and Cullen cinereum. In silico analysis of these three libraries identified nearly 800 cDNA fragments encoding for P450s. Previous studies in the laboratory and comparative transcriptome analysis of these three plants have led us to focus on the subfamily CYP71AZ through a detailed study of CYP71AZ3 and CYP71AZ4. Functional characterization of these enzymes was performed in an eukaryote heterologous expression system: Saccharomyces cerevisiae. The results showed that CYP71AZ4 had a broad substrate specificity enough as it could metabolize one FC and 4 coumarins. The analysis and comparison of the kinetic constants for each of these substrates indicate, however, that the preferred substrate is psoralen. The functional characterization of CYP71AZ3 showed that this enzyme could hydroxylate esculetin, a coumarin, but played no role in the synthesis of FCs. This study highlights the functional diversity within a single enzyme subfamily and allows to issue new hypotheses about the emergence of this biosynthetic pathway in Apiaceae on one hand, and among other botanical families on the other hand

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