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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.
291

Species-independent MicroRNA Gene Discovery

Kamanu, Timothy K. 12 1900 (has links)
MicroRNA (miRNA) are a class of small endogenous non-coding RNA that are mainly negative transcriptional and post-transcriptional regulators in both plants and animals. Recent studies have shown that miRNA are involved in different types of cancer and other incurable diseases such as autism and Alzheimer’s. Functional miRNAs are excised from hairpin-like sequences that are known as miRNA genes. There are about 21,000 known miRNA genes, most of which have been determined using experimental methods. miRNA genes are classified into different groups (miRNA families). This study reports about 19,000 unknown miRNA genes in nine species whereby approximately 15,300 predictions were computationally validated to contain at least one experimentally verified functional miRNA product. The predictions are based on a novel computational strategy which relies on miRNA family groupings and exploits the physics and geometry of miRNA genes to unveil the hidden palindromic signals and symmetries in miRNA gene sequences. Unlike conventional computational miRNA gene discovery methods, the algorithm developed here is species-independent: it allows prediction at higher accuracy and resolution from arbitrary RNA/DNA sequences in any species and thus enables examination of repeat-prone genomic regions which are thought to be non-informative or ’junk’ sequences. The information non-redundancy of uni-directional RNA sequences compared to information redundancy of bi-directional DNA is demonstrated, a fact that is overlooked by most pattern discovery algorithms. A novel method for computing upstream and downstream miRNA gene boundaries based on mathematical/statistical functions is suggested, as well as cutoffs for annotation of miRNA genes in different miRNA families. Another tool is proposed to allow hypotheses generation and visualization of data matrices, intra- and inter-species chromosomal distribution of miRNA genes or miRNA families. Our results indicate that: miRNA and miRNA genes are not only species-specific but may also be DNA strand-specific and chromosome-specific; the genomic distribution of miRNA genes is conserved at the chromosomal level across species; miRNA are conserved; More than one miRNA with different regulatory targets can be excised from one miRNA gene; Repeat-related miRNA and miRNA genes with palindromic sequences may be the largest subclass of miRNA class that have eluded detection by most computational and experimental methods.
292

[en] THE DELIMITATION OF ADJECTIVES AS A LEXICAL CATEGORY IN LANGUAGE ACQUISITION: AN EXPERIMENTAL STUDY IN BRAZILIAN PORTUGUESE / [pt] A DELIMITAÇÃO DO ADJETIVO COMO CATEGORIA LEXICAL NA AQUISIÇÃO DA LINGUAGEM: UM ESTUDO EXPERIMENTAL NO PORTUGUÊS BRASILEIRO

LUCIANA TEIXEIRA 08 October 2009 (has links)
[pt] Este trabalho se caracteriza como um estudo experimental, cujo foco é a delimitação da categoria adjetivo por crianças adquirindo o Português Brasileiro (PB) como língua materna. Adota-se uma perspectiva psicolingüística de aquisição da linguagem, aliada a uma concepção minimalista de língua (Chomsky, 1995-2001). Assume-se que a criança é sensível às propriedades fônicas de elementos de classes fechadas, como determinantes e afixos, conforme a hipótese do bootstrapping fonológico (Morgan & Demuth, 1996; Christophe et al., 1997). Considera-se que a representação da Categoria funcional D é fundamental na distinção entre nomes e adjetivos e que sufixos derivacionais contribuem para a representação do traço categorial desses últimos no léxico. Com base na hipótese do bootstrapping sintático (Gleitman, 1990), assume-se que a análise de adjetivos no contexto sintático de DPs ou de small clauses, aliada ao pressuposto de que DPs fazem referência a objetos/entidades, possibilita a representação de adjetivos como categoria que apresenta uma propriedade ou atributo de um referente. Avalia-se, ainda, o papel da ordem canônica, na distinção entre adjetivos e nomes, na ausência de informação de natureza morfológica. Neste trabalho, uma ampla revisão da literatura lingüística acerca da categoria adjetivo é apresentada de modo a que se identifique o que é demandado da criança na delimitação dessa categoria lexical, levando-se em conta propriedades do português. Foram conduzidos quatro experimentos: três com crianças, usando-se a técnica de seleção de objetos com pseudopalavras, e um com adultos falantes do PB. Para este último, foi concebida uma tarefa de atribuição de propriedades a objetos e pessoas a serem imaginadas a partir de pseudo-adjetivos denominais, de modo a avaliar em que medida as propriedades semânticas atribuídas a sufixos derivacionais formadores de adjetivos em análises lingüísticas correspondem ao conhecimento lingüístico intuitivo do falante da língua. Os dois primeiros experimentos foram conduzidos com crianças de 12-22 meses; o último, com crianças de 2-3 anos e 4-5 anos No Experimento 1, avalia-se o papel de determinantes e sufixos derivacionais, formadores de adjetivos, na delimitação desta categoria lexical em estruturas predicativas, independentemente das propriedades semânticas dos afixos. No Experimento 2, investiga-se o papel da ordem canônica aliada ao do sufixo derivacional como desencadeadores do processo de delimitação de nomes e adjetivos no âmbito do DP. No Experimento 3, explora-se o conhecimento por parte de falantes adultos do PB acerca dos traços semânticos dos afixos derivacionais -oso e -ento, formadores de adjetivos. No Experimento 4, verifica-se se os traços semânticos desses afixos são representados pela criança de modo a ser capaz de interpretá-los na interface semântica, à semelhança do que fazem os falantes adultos da língua. Os resultados dos experimentos aqui relatados são compatíveis com a hipótese de trabalho que orienta esta tese, qual seja, a de que a criança faz uso de informação sintática e morfológica na delimitação de adjetivos, e revelam que já aos dois anos de idade propriedades semânticas de sufixos formadores de adjetivos são representadas pela criança. Este trabalho contribui para uma teoria da aquisição da linguagem fundada no processamento de informação das interfaces da língua com sistemas perceptuais e conceptuais, na qual se enfatiza o papel de categorias funcionais e de elementos de classe fechada em geral (incluindo-se os afixos derivacionais) na identificação do que há de específico na língua. Este estudo também introduz uma metodologia experimental que permite complementar o resultado de análises lingüísticas pertinentes à morfologia no que concerne o conhecimento intuitivo do falante acerca dos traços semânticos de afixos. / [en] This dissertation presents an experimental study of the delimitation of adjectives as a lexical category in the acquisition of Brazilian Portuguese. It reconciles a psycholinguistic approach to language acquisition with a minimalist conception of language (Chomsky, 1995-2001). According to the phonological bootstrapping hypothesis (Morgan & Demuth, 1996; Christophe et al., 1997), it is assumed that infants are sensitive to closed class elements (as determiners and affixes) in the processing of the phonetic interface. The functional category D is considered to be fundamental to the distinction between nouns and adjectives, and derivational suffixes are viewed as contributing to the representation of the adjective as a categorical feature in the lexicon. According to the syntactic bootstrapping hypothesis (Gleitman, 1990), it is assumed that the parsing of adjectives in DP and small clause contexts, together with the assumption that DPs refer to objects/entities, allow the representation of the adjectives as words that present a property or an attribute of a given referent. And the role of the canonical word order in the distinction between nouns and adjectives, in the absence of specific morphological information, is evaluated. In this study, the linguistic literature on adjectives is extensively reviewed. This review contributes to the identification of the demands that the delimitation of adjectives present to children, taking into account the specific properties of Portuguese. Four experiments were conducted: three with children, making use of the object selection with pseudo-words paradigm, and one with adult speakers of BP. In the latter, a task was envisaged in which pseudo-adjectives were presented in order for the property of a hidden object/character to be guessed. The speaker’s intuitive knowledge of the meaning of derivational suffixes was expected to guide the accomplishment of this task. The two first experiments were conducted with 12- 22 month old children, and the last one, with 2-3 and 4-5 year olds. In Experiment 1, the role of determiners and derivational affixes (forming adjectives) in the parsing of adjectives in predicative structures was evaluated, independently of the semantic properties of those affixes. In Experiment 2, the role of the canonical word order within the DP and derivational affixes in the bootstrapping of the representation of adjectives in Portuguese was investigated. Experiment 3 explores the native speaker knowledge of the semantic features of the adjective forming derivational affixes -oso e -ento. In Experiment 4, children’s representation of these very features is assessed. The results of the experiments reported here are compatible with the working hypothesis, namely, that children make use of syntactic and morphological information in the delimitation of adjectives as a lexical category. They also reveal that the semantic properties of derivation affixes forming adjectives are already available by the age of two. This work contributes to a theory of language acquisition that explores early processing at the language interfaces with perceptual and conceptual systems, and in which the role of closed class elements (including derivational affixes) and functional categories is emphasized. It also introduces an experimental methodology that enables to access the adult speaker’s intuitive knowledge of derivational morphology.
293

Atributos ecológicos de anuros neotropicais: o que podem predizer?

Fontana, Rodrigo Barbosa January 2018 (has links)
O risco de extinção e o declínio populacional de muitas espécies animais na região neotropical estão fortemente relacionados aos processos antrópicos, como a conversão ambiental, mas também aos fatores intrínsecos aos próprios indivíduos, como os atributos. Os anuros correspondem ao grupo vertebrado mais ameaçado atualmente, sofrendo com sérios declínios populacionais. Este trabalho buscou avaliar quais os atributos dos anfíbios neotropicais podem predizer: i) as categorias de ameaça e tendências populacionais destas espécies e ii) a ocorrência de anuros em um ambiente modificado, de matriz agrícola. Para a predição de categorias de ameaça e tendências populacionais utilizamos um banco de dados com atributos de habitat e modos reprodutivos de 3196 espécies de anuros neotropicais. Verificamos que espécies com modos reprodutivos terrestres e desenvolvimento direto tem uma maior tendência a estarem em declínio. Além disso, verificamos que embora os atributos sejam filogeneticamente estruturados, o grau de ameaça parece ser independente de suas histórias evolutivas. Para identificar possíveis relações entre atributos ecológicos e morfológicos de anuros em uma paisagem agrícola no sul do Brasil, registramos a anurofauna com uso de armadilhas de interceptação e queda e procuras ativas em três diferentes distâncias da borda em um ambiente florestal e em uma matriz agrícola. Verificamos que principalmente os atributos ecológicos, como o modo reprodutivo (tanto terrestre como aquático) e o hábito estão relacionados com a ocorrência destas espécies no sistema agrícola, assim como encontramos diferenças entre os atributos morfológicos ao longo do gradiente de distância. Ambos os resultados podem auxiliar na tomada de decisões em planos e projetos de conservação de anuros neotropicais. / The extinction risk and population decline of many animal species in neotropical region are strongly related to anthropic processes, such as environmental conversion, but they are also related to intrinsic factors such as traits. Anurans correspond to the most endangered vertebrate group, suffering serious population declines. This work aimed to evaluate which neotropical anurans traits can predict: i) the categories of threat and population trends of species, and ii) the occurrence of anuran species in modified environments, such as the agricultural matrix. First, we compiled data to 3196 neotropical anuran species. We emphasized the importance of habitat and reproductive modes in threat classifications, as well as verified that species with terrestrial reproductive modes and direct development are more likely to be declining. We also found that although anurans traits being phylogenetically structured, the degree of threat seems to be independent from their evolutionary histories. In addition, to identify possible relation among ecological and morphological anuran traits with agricultural landscape in southern Brazil, we studied the anurofauna using pitfall traps and active searches at three different border distances in a forest environment and in an agricultural matrix. We verified that mostly of the ecological traits, such as the reproductive mode (both terrestrial and aquatic) and the habit, are related to the occurrence of determined species in the agricultural system. And we also found differences among the morphological traits observed through the distance gradient from the border. Therefore, both results present practical importance since it can help herpetologists to making decision about neotropical anurans conservation.
294

Nocaute ! : procedimentos composicionais e categorias estéticas em um portfolio de composições

Laitano, Yanto dos Santos January 2006 (has links)
O presente trabalho é uma reflexão sobre os aspectos técnicos e estéticos do processo de criação de um portfolio de composições. Esta reflexão está fundamentada nos trabalhos de Leonard B. Meyer (1973), Étienne Souriau (1999) e Ilza Nogueira (2003). Os aspectos técnicos estão ligados aos procedimentos composicionais “paródia” e “relações de correspondência” e os aspectos estéticos referem-se às categorias estéticas “bizarro”, “cômico”, “fantástico” e “insólito”. Em todas as composições deste portfolio ocorrem esses procedimentos composicionais e categorias estéticas, em algumas composições mais, em outras menos. São realizadas reflexões sobre o processo composicional de cada uma das peças, individualmente, e, em seguida, considerações sobre como a “paródia”, as “relações de correspondência” e as categorias estéticas atuam em cada uma das composições. / This work is a discussion on the technical and aesthetic aspects of the composition of a group of pieces. The discussion is based on works by Leonard B. Meyer (1973), Étienne Souriau (1999) and Ilza Nogueira (2003). The technical aspects of the composition are related to the compositional procedures "parody" and "conformant relationships"; its aesthetic aspects are related to the aesthetic categories to it "bizarre", "comical", "fantastic" and "uncommon". Such procedures and aesthetic categories occur in the entire group of pieces, to various degrees of importance. A discussion is made on the composicional process of each individual piece followed by considerations on how "parody", "the conformant relationships" and aesthetical categories are integrated throughout the group of pieces.
295

Dualité homologique projective et résolutions catégoriques des singularités / Homological Projective Duality and Categorical Resolution of Singularities

Abuaf, Roland 01 July 2013 (has links)
Soit $X$ une variété algébrique de Gorenstein à singularités rationnelles. Une résolution des singularités crépante de $X$ est souvent considérée comme une résolution des singularités minimales de $X$. Malheureusement, les résolutions crépantes sont très rares. Ainsi, les variétés déterminantielles de matrices anti-symétriques n'admettent jamais de résolution crépante des singularités. Dans cette thèse, on discutera de diverses notions de résolutions catégoriques crépantes développées par Alexander Kuznetsov. Conjecturalement, ces résolutions doivent être minimale du point de vue catégorique. On introduit dans ce manuscrit la notion de résolution magnifiques des singularités et on montre que tout variété munie d'une telle résolution admet une résolution catégorique faiblement crépante. On en déduit que toutes les variétés déterminantielles (carrées, symétriques et anti-symétriques) admettent des résolutions catégoriques faiblement crépantes. Finalement, on s'intéressera à des hypersurfaces quartiques issues du carré magique de Tits-Freudenthal. On ne peut pas construire de résolution magnifique des singularités pour de telles hypersurfaces, mais on montrera qu'elles admettent tout de même des résolutions catégorique faiblement crépantes des singularités. Ce résultat devrait s'avérer intéressant pour la construction de duales projectives homologiques de certaines Grassmaniennes symplectiques sur les algèbres de composition. / Let $X$ be an algebraic variety with Gorenstein rational singularities. A crepant resolution of $X$ is often considered to be a minimal resolution of singularities for $X$. Unfortunately, crepant resolution of singularities are very rare. For instance, determinantal varieties of skew-symmetric matrices never admit crepant resolution of singularities. In this thesis, we discuss various notions of categorical crepant resolution of singularities as defined by Alexander Kuznetsov. Conjecturally, these resolutions are minimal from the categorical point of view. We introduce the notion of wonderful resolution of singularities and we prove that a variety endowed with such a resolution admits a weakly crepant resolution of singularities. As a corollary, we prove that all determinantal varieties (square, as well as symmetric and skew-symmetric) admit weakly crepant resolution of singularities. Finally, we study some quartics hypersurfaces which come from the Tits-Freudenthal magic square. Though they do no admit any wonderful resolution of singularities, we are still able to prove that they have a weakly crepant resolution of singularities. This last result should be of interest in order to construct homological projective duals for some symplectic Grassmannians over the composition algebras.
296

Teorema de Morita para categoria derivada / Morita theorem for category derived

Fidélis, Michele Ribeiro 26 July 2013 (has links)
Made available in DSpace on 2015-03-26T13:45:35Z (GMT). No. of bitstreams: 1 texto completo.pdf: 762080 bytes, checksum: 36946445ac63cb1213a2aaceb16cdb53 (MD5) Previous issue date: 2013-07-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work we present concepts and results of triangulated and derived categories. The main objective is to prove Rickard s theorem, also known as Morita s theorem for derived categories. As an application of this result we show that finiteness of finitistic dimension is invariant under derived equivalences, as it is proved in Finiteness of finitistic dimension is invariant under derived equivalences by Shengyong Pan and Changchang Xi. / Neste trabalho apresentamos conceitos e resultados de categorias trianguladas e derivadas. O principal objetivo é demonstrar o Teorema de Rickard, também conhecido como Teorema de Morita para categorias derivadas. Como aplicação deste resultado mostramos que a dimensão finítistica é preservada por equivalência derivada, conforme o artigo "Finiteness of finitistic dimension is invariant under derived equivalences" de Shengyong Pan e Changchang Xi.
297

Atributos ecológicos de anuros neotropicais: o que podem predizer?

Fontana, Rodrigo Barbosa January 2018 (has links)
O risco de extinção e o declínio populacional de muitas espécies animais na região neotropical estão fortemente relacionados aos processos antrópicos, como a conversão ambiental, mas também aos fatores intrínsecos aos próprios indivíduos, como os atributos. Os anuros correspondem ao grupo vertebrado mais ameaçado atualmente, sofrendo com sérios declínios populacionais. Este trabalho buscou avaliar quais os atributos dos anfíbios neotropicais podem predizer: i) as categorias de ameaça e tendências populacionais destas espécies e ii) a ocorrência de anuros em um ambiente modificado, de matriz agrícola. Para a predição de categorias de ameaça e tendências populacionais utilizamos um banco de dados com atributos de habitat e modos reprodutivos de 3196 espécies de anuros neotropicais. Verificamos que espécies com modos reprodutivos terrestres e desenvolvimento direto tem uma maior tendência a estarem em declínio. Além disso, verificamos que embora os atributos sejam filogeneticamente estruturados, o grau de ameaça parece ser independente de suas histórias evolutivas. Para identificar possíveis relações entre atributos ecológicos e morfológicos de anuros em uma paisagem agrícola no sul do Brasil, registramos a anurofauna com uso de armadilhas de interceptação e queda e procuras ativas em três diferentes distâncias da borda em um ambiente florestal e em uma matriz agrícola. Verificamos que principalmente os atributos ecológicos, como o modo reprodutivo (tanto terrestre como aquático) e o hábito estão relacionados com a ocorrência destas espécies no sistema agrícola, assim como encontramos diferenças entre os atributos morfológicos ao longo do gradiente de distância. Ambos os resultados podem auxiliar na tomada de decisões em planos e projetos de conservação de anuros neotropicais. / The extinction risk and population decline of many animal species in neotropical region are strongly related to anthropic processes, such as environmental conversion, but they are also related to intrinsic factors such as traits. Anurans correspond to the most endangered vertebrate group, suffering serious population declines. This work aimed to evaluate which neotropical anurans traits can predict: i) the categories of threat and population trends of species, and ii) the occurrence of anuran species in modified environments, such as the agricultural matrix. First, we compiled data to 3196 neotropical anuran species. We emphasized the importance of habitat and reproductive modes in threat classifications, as well as verified that species with terrestrial reproductive modes and direct development are more likely to be declining. We also found that although anurans traits being phylogenetically structured, the degree of threat seems to be independent from their evolutionary histories. In addition, to identify possible relation among ecological and morphological anuran traits with agricultural landscape in southern Brazil, we studied the anurofauna using pitfall traps and active searches at three different border distances in a forest environment and in an agricultural matrix. We verified that mostly of the ecological traits, such as the reproductive mode (both terrestrial and aquatic) and the habit, are related to the occurrence of determined species in the agricultural system. And we also found differences among the morphological traits observed through the distance gradient from the border. Therefore, both results present practical importance since it can help herpetologists to making decision about neotropical anurans conservation.
298

Etologické projevy ovcí v průběhu pastevního období / Ethological manifestations sheep along pastoral season

KOUTNÁ, Zdeňka January 2008 (has links)
The aim of the thesis is to write down and evaluate the base categories of the sheep grazing behaviour during one grazing period as regards the various climatic conditions. The method of the direct observation was used when the length of interval was 10 minutes. It was done five times for always 24 hours during a grazing period. The longest time of the grazing (43,8 % of the day) was found out in July. High temperatures shortened the time of the grazing to 26,8 % of the day. If the growth is of poor quality the time of the movement is lengthened out to 10 % of the day. The longest time of the lying category was found out in August (54,4 % of the day).
299

Thoughts don't have Colour, do they? : Finding Semantic Categories of Nouns and Adjectives in Text Through Automatic Language Processing / Generering av semantiska kategorier av substantiv och adjektiv genom automatisk textbearbetning

Fallgren, Per January 2017 (has links)
Not all combinations of nouns and adjectives are possible and some are clearly more fre- quent than other. With this in mind this study aims to construct semantic representations of the two types of parts-of-speech, based on how they occur with each other. By inves- tigating these ideas via automatic natural language processing paradigms the study aims to find evidence for a semantic mutuality between nouns and adjectives, this notion sug- gests that the semantics of a noun can be captured by its corresponding adjectives, and vice versa. Furthermore, a set of proposed categories of adjectives and nouns, based on the ideas of Gärdenfors (2014), is presented that hypothetically are to fall in line with the produced representations. Four evaluation methods were used to analyze the result rang- ing from subjective discussion of nearest neighbours in vector space to accuracy generated from manual annotation. The result provided some evidence for the hypothesis which suggests that further research is of value.
300

Representações torcidas de quivers / Twisted representations of quivers

Prata, Daniela Moura, 1984- 26 February 2008 (has links)
Orientador: Marcos Benevenuto Jardim / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-10T08:38:10Z (GMT). No. of bitstreams: 1 Prata_DanielaMoura_M.pdf: 537246 bytes, checksum: 34750d4837b03d877cf678e318e84f40 (MD5) Previous issue date: 2008 / Resumo: Nesta dissertação o principal objetivo é introduzir na categoria de representações torcidas de um quiver Q as definições e resultados já co-nhecidos para categorias de representações de quivers. O conceito de reapresentações torcidas foi introduzido por Gothen e King em [11] para estudar problemas envolvendo fibrados vetoriais sobre variedades algébricas. King também mostrou em [16] que, sobre certas condições, as representações semi-estáveis de um quiver são parametrizadas por uma variedade algébrica projetiva, normal, irredutível. Mostramos que o mesmo vale para representações torcidas de quivers. Nosso principal resultado, que 'e original, mostra equivalência entre a categoria de representações M - torcidas de um quiver Q, RepMQ, e a categoria de representações de um quiver ¿Q, Rep , onde Q depende de Q e dos espaços de M. Essa equivalência nos permitiu desenvolver um pouco da teoria já conhecida para Rep ¿Q na linguagem de RepMQ, reescrever resultados clássicos como o Teorema de Gabriel e de Kac para a categoria de representações torcidas e também relacionar RepQ com RepMQ / Abstract: The main goal of this thesis is to introduce for the category of twisted representations of a quiver Q the definitions and results one already knows for categories of representations of quivers. The concept of twisted representations was introduced by Gothen and King in [11] to study problems concerning vector bundles over algebraic varieties. King also showed in [16] that under certain conditions, semi-stable representations of a quiver are parametrized by an irreducible, normal projective algebraic variety. We show that we have the same results for twisted representations. Our main and original result provides an equivalence between the category of twisted representations of a quiver Q, RepMQ, and the category of representations of a quiver Q, Rep ¿Q, where ¿Q depends on Q and on the twisting factors. With this equivalence we developed the existing theory of representations of quivers for twisted representations, we rewrote classical results like Gabriel¿s theorem and Kac¿s theorem for the category of twisted representations and found a relation between RepQ and RepMQ / Mestrado / Algebra / Mestre em Matemática

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