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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.
151

Estudo geoacústico para mapeamento de eco-caráter em registros sísmicos de alta resolução do interior da Lagoa Dos Patos, RS, Brasil

Bexiga, Gabriela Muller Sampaio January 2016 (has links)
A Lagoa dos Patos, por sua importância e magnitude, é alvo de inúmeras pesquisas relacionadas ao seu contexto evolutivo geológico e paleogeográfico. Para a investigação das características de seu fundo e subfundo, foram executados, nos anos de 2002 e 2006, levantamentos de cerca de 700 Km de dados sísmicos de 3,5 kHz. O presente trabalho considerou aproximadamente 153 Km de registros sísmicos levantados na célula sul da Lagoa dos Patos, objetivando a identificação e mapeamento dos eco-caracteres da área. Para integração dos dados e visualização dos resultados finais, métodos de geoprocessamento foram aplicados. Os perfis sísmicos analisados permitiram a identificação de três principais eco-caracteres, que foram agrupados de acordo com o aspecto do refletor primário (fundo), ocorrência de refletores subsuperfície e geometria dos refletores de subsuperfície. O eco-caráter A se foi definido por refletor primário (fundo) plano e forte, seguido por refletores fortes e bem definidos; o eco-caráter B foi caracterizado a partir de refletor primário difuso e reflexões de subsuperfície pouco definidas, difusas ou com aspecto de manchas; o eco-caráter C consistiu em refletor primário plano e muito forte, seguido por sucessivas reflexões múltiplas de baixa perda. Estes eco-caracteres foram relacionados à batimetria da área e aos sedimentos de fundo do local, de forma observar a relação entre estes e a resposta acústica associada ao eco. Os eco-caracteres identificados foram correlacionáveis às características sedimentológicas da área e aos processos hidrodinâmicos atuantes na célula sul do sistema lagunar. Anomalias acústicas identificadas nos registros sonográficos evidenciaram a ocorrência de grande quantidade de gás raso, disseminado nos pacotes sedimentares intralagunares. Este trabalho confirma a importância de um melhor entendimento dos efeitos da hidrodinâmica nos processos de sedimentação e apresenta informações relevantes para o auxílio de estudos geomorfológicos e hidrodinâmicos a serem realizados na Lagoa dos Patos. / The Patos Lagoon, for its importance and magnitude, is the subject of numerous researches related to its geological and paleogeographic evolutionary context. For the investigation of its bottom and subbottom characteristics, about 700 km of seismic data of 3.5 kHz were surveyed in 2002 and 2006. This study considered nearly 153 Km of seismic records collected in the south of the Patos Lagoon cell, aiming to the identification and mapping of echo-character. For data integration and visualization of the results, geoprocessing methods were applied. The seismic profiles analyzed allowed the identification of three major echo-characters, which were grouped according to the aspect of the primary reflector (bottom), the occurrence of subbottom reflections, the geometry of the subbottom reflections. The echo-character A presented distinct and continuous surface (bottom) with well-defined subbottom reflections, generally parallel and continuous, which follow the topography of the surface; echo-character B was characterized by a diffuse primary reflector and poorly defined subbottom reflections, diffuse or blurry; echo-character C consisted of a plane and very strong well-defined first reflector and presents a series of low loss multiple reflections. These echo-characters were related to the bathymetry and the bottom sediments of the area, in order to observe the relationship between them and the acoustic response associated with the echo. The echo-characters identified presented good correlation to the sedimentological characteristics of the area and the hydrodynamic processes acting in the south cell of the lagoon system. Acoustic anomalies identified in ecograms indicate the occurrence of large amounts of shallow gas spread in intra-lagoon sedimentary packages. This study confirms the importance of a better understanding of the effects of hydrodynamics in sedimentation processes and presents relevant information to support geomorphological and hydrodynamics studies to be conducted in the Patos Lagoon.
152

Ambiente de medição da audiência para TV digital. / Audience measurement environment for digital TV.

Becker, Valdecir 06 July 2011 (has links)
Esta tese representa um esforço sistemático de investigar a audiência televisiva no âmbito do Sistema Brasileiro de TV Digital (SBTVD). Analisando as teorias atuais da audiência e suas técnicas de medição, percebe-se uma série de problemas em aplicar as mesmas na medição da audiência na TV digital. Além de permitir mais canais na mesma frequência espectral, a tecnologia digital possibilita o acesso ao conteúdo audiovisual por diversas formas e redes, gerando um aumento de opções para o telespectador. Esses aspectos não são contemplados pelas medições tradicionais. Com base nessa análise, propõe-se incluir nas medições de audiência o contexto em que ela ocorre. Ou seja, além dos números de pessoas assistindo à programação, propõe-se analisar as motivações que levam a audiência a ver determinado programa ou trocar de canal. Para tanto, foi desenvolvido um novo modelo teórico para subsidiar a medição da audiência. Usando a teoria da atividade como arcabouço teórico, foram desenvolvidos perfis de usuário, que permitem segmentar as análises de audiência. Também foi incorporada a geolocalização, que relaciona a audiência com o local da recepção. Para os testes foi desenvolvido um sistema de medição de audiência, que colhe informações em tempo real e por software sobre o canal virtual que está sendo visualizado. As informações podem ser recuperadas por acesso web. Estando o Brasil em fase inicial da implantação da TV digital, estudos sobre a audiência nessa mídia podem colaborar na definição de novos modelos de negócio, direcionando os investimentos publicitários. / This thesis represents a systematic effort to investigate the television audience in the Brazilian Digital TV System (SBTVD). Analyzing the current theories of the audience and their measurement techniques, we can see a lot of problems in applying them in the digital TV environment. Besides allowing more channels at the same frequency spectrum, digital technology enables access to audiovisual content in various forms and networks, generating increasing options for the viewer. These aspects are not covered by traditional measurements systems. Based on this analysis, this thesis proposes to include in the measurement techniques the context in which the audience occurs. That is, beyond the numbers of people watching TV schedule, it analyzes the motivations that lead the audience to see particular program or do a channel exchanging. To that end, we developed a new theoretical model to support the audience measurement. Using activity theory as theoretical framework, user profiles were developed. It allows analysis of the target audience. We also incorporated geolocation, which relates the audience with the reception site. For the tests we developed a system of audience measurement, which collects real- time information by software about the virtual channel being viewed. Information can be retrieved by web access. With Brazil in the early phase of deployment of digital TV, studies on this media audience can help to define new business models, directing the advertising investment.
153

Extremos de precipitação diária em Belém, Pará, e estrutura vertical da atmosfera / Extreme daily rainfall in Belém, Pará, and vertical structure of atmosphere

Camponogara, Glauber 06 March 2012 (has links)
Diversas atividades ligados ao gerenciamento de recursos hídricos necessitam da previsão de acumulados diários de chuva extremos. Entretanto, grande parte dos modelos utilizados operacionalmente apresentam uma tendência a subestimar os extremos de precipitação mesmo com apenas 24 horas de antecedência. Existem diversas razões para esse tipo de erro de previsão tais como, limitações nas parametrizações de convecção para modelos com resolução de dezenas de quilômetros e a não inclusão do efeito de aerossóis como núcleos de condensação de gotas de nuvens nos modelos de grande escala. Dentro desse contexto, este trabalho tem como objetivo analisar situações de eventos extremos de precipitação na região de Belém, Pará, onde o regime de precipitação é modulado, principalmente, pela brisa marítima, linhas de instabilidade, distúrbios ondulatório de leste, zona de convergência intertropical, alta da Bolívia e Vórtices Ciclônicos de Altos Níveis (VCAN). A abordagem será de identificação de perfis verticais cinemáticos e termodinâmicos típicos de eventos extremos de precipitação diária em Belém, Pará. Para esse fim, escolheu-se fazer uma análise de dados de radiossondagem e precipitação utilizando as Funções Ortogonais Empíricas (EOF - Empirical Orthogonal Functions combinadas e verificar como o Brazilian developments on the Regional Atmospheric Modeling System (BRAMS) simula características básicas de chuva acumulada diária. A variância explicada das EOF calculadas a partir do conjunto de variáveis acumulado diário de precipitação (acpcp), temperatura (t), razão de mistura de vapor d\'água (rv), vento zonal (u) e vento meridional (v) e acpcp, u e v apresentaram valores de variância explicada baixos em relação as EOF calculadas a partir de acpcp e u somente. A terceira EOF (e3) foi a que melhor identificou os extremos chuvosos em relação a primeira e segunda. Observou-se padrões sinóticos favoráveis a convecção para os dias relativos à acumulados de chuva acima da média e menos favoráveis para os dias relativos à acumulados de chuva abaixo da média. Nos dias que apresentaram os maiores acumulados de chuva identificados por e3 verificou-se a presença da Alta da Bolívia e de um VCAN sobre o Oceano Atlântico influenciando a região de estudo. Observou-se um caso de uma linha de instabilidade que adentrou o continente associada a um jato de baixos níveis e outro caso de uma perturbação de latitudes médias, ambos os casos ocasionaram acumulados de chuva acima da média. O BRAMS apresentou máximos e mínimos de anomalias de acpcp coincidentes com os dados observados. Os dias relativos à acumulados de chuva acima da média apresentaram correntes ascendentes e descendentes mais intensas que os dias relativos à acumulados de chuva abaixo da média. Observou-se máximos de correntes ascendentes associados a formação de novas células convectivas. / Several activities related to water management need the forecasting of cumulative daily rainfall extreme. However, most of the models used operacionaly tend to underestimate the extreme rainfall even with 24 hours of advance. There are several reasons for this type of forecast error such as, limitations in convection parametrizations for models with resolution of tens of kilometers and not inclusion of the effect of aerosols as cloud condensation nuclei for cloud droplets in large-scale models. Withing this context, this study aims to analyze situations of extreme precipitation events in the region of Belém, Pará, where the rainfall regime is modulated mainly by sea breeze, squall lines, easterly wave disturbances, intertropical convergence zone, Bolivian high and cyclonic vortices of high levels (VCAN). The approach will be to identify kinematic and thermodynamics vertical profiles typical of extreme daily rainfall events in Belém, Pará. To this end, it was chosen to analyze sounding and rainfall data using the combined Empirical Orthogonal Functions (EOF) and verify how the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS) simulates the basic features of daily accumulated rainfall. The explained variance of EOF calculated from the set of variables accumulated daily precipitation (acpcp), temperature (t), mixing ratio of water vapor (rv), zonal wind (u) e meridional wind (v) and acpcp, u and v showed low values of explained variance in relation to the EOF calculated from acpcp and u only. The third EOF (e3) was the best in the identification of extreme rainfall compared to first and second. Observed synoptic patterns are favorable to convection on days with accumulated rainfall above average and less favorable on days for accumulated rainfall below average. In the days that had the highest accumulated rainfall identified by e3, it was verified that the presence of the Bolivian high and a VCAN on the Atlantic Ocean influence the study region. A case of squall line that entered the continent associated with a low level jet and other case of disturbance of mid-latitudes, resulted in accumulated rainfall above average. The BRAMS presented maximum and minimum acpcp anomalies coincident with the observed data. The days on the accumulated rainfall above average showed more intense updrafts and downdrafts that the days on the accumulated rainfall below average. Observed maximum updrafts associated with the formation of new convective cells.
154

Modelando o efeito da omissão de atributos em um estudo de análise de preferência conjunta / Conjoint analysis model for missing attributes infomation.

Karina Pretto 09 May 2007 (has links)
A Análise de Preferência Conjunta (APC) é uma metodologia estatística bastante utilizada em estudos de comportamento do consumidor e do mercado em geral. Ela possibilita a realização de estudos sobre julgamentos individuais, tais como a aceita-bilidade e preferência por um determinado produto no momento da sua aquisição (ver Artes, 1991 e Friedmann, 1998). Em um estudo de preferência conjunta, são apresentadas configurações hipotéticas de um mesmo produto, que devem ser avaliadas segundo a preferência do respondente. O julgamento de um estímulo é denominado de valor de preferência que nada mais é do que a quantificação da preferência do indivíduo por um estímulo. Quanto maior o número de atributos e níveis utilizados na caracterização de um produto, mais real será sua descrição. No entanto, a complexidade dos estímulos e o número de configurações possíveis aumenta exponencialmente a cada novo atributo ou nível acrescentado, podendo comprometer a qualidade dos resultados de uma pesquisa. Este problema é contornado através da utilização de estímulos gerados através de planejamentos fracionários combinado na omissão de um ou mais atributos nos diferentes estímulos, conhecidos como perfis incompletos. Neste trabalho, pretende-se testar o efeito da ausência de atributos na classificação de estímulos e diferentes formas de imputação da informação faltante em uma aplicação sobre o efeito de características do emprego na satisfação do funcionário. / Conjoint Analysis is a statistic technique used in many behavior studies, product management and marketing researches. The conjoint method involves presenting customers with a test set of hypothetical products profiles and collecting their preferences. It\'s task is to identify some within a set of attributes those ones that are the most important for the research participants. Conjoint Analysis works better when the test set of profiles is small and the number of attributes is not so large. When a large number of attributes are considered in a conjoint study, the final number of possible profiles increase a lot. In this cases, fractional designs and incomplete profiles can be used to solve this problem. In this study will be tested the missing information efect in a conjoint study and will be compared some diferent imputations methods.
155

Ambiente de medição da audiência para TV digital. / Audience measurement environment for digital TV.

Valdecir Becker 06 July 2011 (has links)
Esta tese representa um esforço sistemático de investigar a audiência televisiva no âmbito do Sistema Brasileiro de TV Digital (SBTVD). Analisando as teorias atuais da audiência e suas técnicas de medição, percebe-se uma série de problemas em aplicar as mesmas na medição da audiência na TV digital. Além de permitir mais canais na mesma frequência espectral, a tecnologia digital possibilita o acesso ao conteúdo audiovisual por diversas formas e redes, gerando um aumento de opções para o telespectador. Esses aspectos não são contemplados pelas medições tradicionais. Com base nessa análise, propõe-se incluir nas medições de audiência o contexto em que ela ocorre. Ou seja, além dos números de pessoas assistindo à programação, propõe-se analisar as motivações que levam a audiência a ver determinado programa ou trocar de canal. Para tanto, foi desenvolvido um novo modelo teórico para subsidiar a medição da audiência. Usando a teoria da atividade como arcabouço teórico, foram desenvolvidos perfis de usuário, que permitem segmentar as análises de audiência. Também foi incorporada a geolocalização, que relaciona a audiência com o local da recepção. Para os testes foi desenvolvido um sistema de medição de audiência, que colhe informações em tempo real e por software sobre o canal virtual que está sendo visualizado. As informações podem ser recuperadas por acesso web. Estando o Brasil em fase inicial da implantação da TV digital, estudos sobre a audiência nessa mídia podem colaborar na definição de novos modelos de negócio, direcionando os investimentos publicitários. / This thesis represents a systematic effort to investigate the television audience in the Brazilian Digital TV System (SBTVD). Analyzing the current theories of the audience and their measurement techniques, we can see a lot of problems in applying them in the digital TV environment. Besides allowing more channels at the same frequency spectrum, digital technology enables access to audiovisual content in various forms and networks, generating increasing options for the viewer. These aspects are not covered by traditional measurements systems. Based on this analysis, this thesis proposes to include in the measurement techniques the context in which the audience occurs. That is, beyond the numbers of people watching TV schedule, it analyzes the motivations that lead the audience to see particular program or do a channel exchanging. To that end, we developed a new theoretical model to support the audience measurement. Using activity theory as theoretical framework, user profiles were developed. It allows analysis of the target audience. We also incorporated geolocation, which relates the audience with the reception site. For the tests we developed a system of audience measurement, which collects real- time information by software about the virtual channel being viewed. Information can be retrieved by web access. With Brazil in the early phase of deployment of digital TV, studies on this media audience can help to define new business models, directing the advertising investment.
156

CORRELATION BETWEEN EMISSION LINES AND RADIO LUMINOSITIES OF ACTIVE GALACTIC NUCLEI

Short-Long, Jessica 01 January 2018 (has links)
Radio-loud active galactic nuclei (AGN) are one class of objects associated with accretion activity onto supermassive black holes in centers of massive galaxies. They are believed to be in a radiatively-inefficient accretion mode with low accretion rate. To understand this accretion mode, it is important to measure its radiative output at high energies (> 13.6eV), which can be traced through optical emission lines. However, little is known about their true radiative output. This is because no correlation between optical emission-line and radio luminosity has been found for the majority of low-luminosity radio AGN, which are often classified as low-excitation radio galaxies, or Fanaroff-Riley Class I (FR-I) radio galaxies. We demonstrate that most of the line emission found in these galaxies is not powered by the central AGN, but likely powered by some old stellar population. Only when this component is subtracted or otherwise taken into account can we estimate the true line emission associated with the AGN. These emissions may show interesting correlations with the radio luminosities in some cases.
157

ANALYSIS OF UNDERGROUND COAL MINE STRUCTURES SUBJECTED TO DYNAMIC EVENTS

Yonts, Brooklynn 01 January 2018 (has links)
Underground coal mine explosions pose a significant threat to infrastructure such as mine seals and refuge alternative chambers. After a mine seal failed in the Sago mine disaster, which took the life of 12 miners, design requirements were reexamined and improved. However, most research being completed on the analysis of mine structures during an explosive event focuses solely on peak pressure values, while ignoring the impact of pressure duration. This study investigates the impact pressure duration, waveform shape, and impulse have on structural displacement, while also exploring what pressures and duration can be expected during a mine explosion. Additionally, the use of high explosives to simulation conditions experienced during a mine explosion is examined. Results from this study are produced through experimental testing using a scaled shock tube and theoretical studies using finite element analysis.
158

Estimation of Selected Milk Protein Genetic Variants by Multi-Component Analysis of Amino Acid Profiles

Hollar, Carol M. 01 May 1992 (has links)
Cation-exchange fast protein liquid chromatography separated whole casein into β-casein A2, A1, and B, K-casein, αs1-casein, and αs2-casein fractions as well as γ-caseins and several unidentified peaks using a urea-acetate buffer at pH 5 and a NaCl gradient. The whole casein fractions eluted in the following order: breakdown products of β-casein and unidentified peaks; β-casein A2, Al, and B; additional breakdown products of β-casein and unidentified peaks; K-casein; αs1-casein; and αs2-casein. The calculated composition of the four major caseins correlated well with values obtained using anion-exchange fast protein liquid chromatography at pH 7. An acid-PAGE gel confirmed that the three β-casein peaks were variants of β-casein. Incubating herd bulk whole casein with neuraminidase (EC 3.2.1.18) removed carbohydrate from K-casein. Anion-exchange fast protein liquid chromatography separated whole casein into β-casein breakdown products, K-casein A and B, β-casein, αs2-casein, and αs1-casein peaks as well as three unidentified fractions using bis-Tris-propane-urea buffer at pH 7 and a NaCl gradient. Fractions of whole casein eluted in the following order: breakdown products of β-casein and unidentified fractions A and B; K-casein fraction; unidentified C fraction; β-casein; αs2-casein; and αs1-casein. Following treatment with neuraminidase, K-casein eluted as K-casein B and A rather than a series of peaks. Casein samples from individual cows containing known combinations of K-casein A and B confirmed that the peaks were K-casein variants. Isoelectric focusing on a PhastSystem™ separated K-casein A and B; β-casein A1, A2, A3, and B; αs1-casein Band C; β-lactoglobulin A and B; αs2-casein A; and α-lactalbumin B. Minimal preparation and a short separation time enabled many whole milk and whole casein samples to be phenotyped daily. Stepwise regression equations derived to predict samples as homozygous or heterozygous for K-casein A and B and β-casein A1, A2, and B had coefficient of determination values of .18, .58, .82, and .72 for K-casein A and B, β-casein A1, β-casein A2, and β-casein B. Although amino acid analysis can identify whether β-casein A1, A2, or B variants are present, it cannot identify whether K-casein A and B variants are present. Percentages of K-casein, β-casein, αs1-casein, and αs2-casein obtained with isoelectric focusing, cation-exchange fast protein liquid chromatography, and anion-exchange fast protein liquid chromatography compare well with published results. Isoelectric focusing and anion-exchange fast protein liquid chromatography methods separated K-casein into its A and B variants. Isoelectric focusing and cation-exchange fast protein liquid chromatography separated β-casein into its A1, A2, and B variants. Individual cows homozygous for K-casein A or B expressed the same amount of K-casein. When results from individual cows heterozygous for K-casein are combined, the two alleles are expressed equally; on an individual cow basis, however, some cows expressed more K-casein B than K-casein A. Individual cows homozygous for β-casein A1, A2 or B expressed the same amount of β-casein. When the results for individual cows heterozygous for β-casein are combined, the two β-casein alleles are expressed equally. In milk from individual cows typed β-casein A2B, slightly more B than A2 was expressed with cation-exchange fast protein liquid chromatography.
159

Intérêt du transcriptome de cellules mononucléées périphériques sanguines dans l’étude des mécanismes moléculaires de la maladie de Parkinson / Transcriptome analysis of peripheral blood mononuclear cells provide insights on molecular mechanisms of Parkinson’s disease

Nkiliza, Aurore 11 December 2015 (has links)
La maladie de Parkinson est une maladie neurodégénérative dont la physiopathologie fait intervenir des causes génétiques qui contribuent non seulement aux formes familiales mais aussi au développement des formes sporadiques, les plus fréquentes, en interagissant sans doute alors avec des facteurs environnementaux. La découverte des déterminants génétiques a permis d’identifier plusieurs mécanismes moléculaires contribuant au développement de la maladie. Ils en ont démontré le caractère complexe. Pour mieux comprendre l’étendue des perturbations moléculaires liées à la maladie, nous avons entrepris des analyses globales du transcriptome par le biais de puces ou de séquençage des ARNs (RNAseq) à partir de cellules mononuclées périphériques sanguines de patients présentant des formes génétiques et sporadiques de la maladie ainsi que de sujets sains.Nous avons identifiés la dérégulation de nombreux gènes dans les cellules mononuclées périphériques sanguines de sujets porteurs de la mutation G2019S de LRRK2 et de sujets sporadiques par rapport à des sujets sains appariés. L’analyse des voies et des processus cellulaires associés à ces gènes met en exergue une altération de la voie de signalisation EIF2 commune aux sujets porteurs de la mutation G2019S de LRRK2 et aux sujets sporadiques. Cette voie fait écho à la régulation de la traduction et de l’épissage, deux processus faisant partie du métabolisme des ARNs. Ces altérations sont retrouvées dans les cellules mononuclées périphériques sanguines de sujets parkinsoniens porteurs de mutations du gène ATXN2, essentiellement connu pour son rôle dans la stabilité, l’épissage et la traduction des ARNm. Cette perturbation des ARNs semble être une altération commune à l’ensemble des formes de maladie de Parkinson étudiées et pourrait donc être un mécanisme sous-tendant la maladie.Les résultats du séquençage des ARNs obtenus chez des parkinsoniens présentant une forme sporadique ou porteurs de mutations délétères ainsi que chez des sujets sains corroborent cette hypothèse en montrant d’une part des différences quantitatives et qualitatives de variants d’épissage au sein d’ARNm eux-mêmes impliqués dans le métabolisme des ARNs et d’autres part des variations de l’épissage de gènes impliqués dans des mécanismes moléculaires connus de la maladie.Ainsi, nos données s’inscrivent dans la dynamique physiopathologique actuelle qui fait état de nombreuses perturbations du métabolisme des ARNs dans les maladies neurodégénératives. Dans la maladie de Parkinson, ces défauts impliqueraient des variations quantitatives et qualitatives de variants d’épissage au sein de gènes liés à l’épissage mais aussi dans des mécanismes connus pour contribuer à la maladie. Une analyse approfondie de ces dérèglements devraient permettre de déterminer leur spécificité et d’évaluer leur potentiel en tant que marqueurs de la maladie et cibles thérapeutiques. / Parkinson’s disease is a neurodegenerative disorder with genetic determinants not only contributing to rare familial forms of the disease but also involved in prevalent sporadic forms by interacting with environmental factors. Thanks to the identification of these determinants, several molecular mechanisms contributing to the disease have been found highlighting also its complexity. In order to better understand the molecular perturbations underlying the disease, we performed whole transcriptome analyses using microarrays and RNA sequencing (RNAseq) from peripheral blood mononuclear cells of Parkinson’s disease patients with genetic and sporadic forms of the disease as well as healthy controls.We identified several dysregulated genes in the cells of Parkinson’s disease patients with a G2019S LRRK2 mutation and sporadic patients compared to healthy controls. Pathways and cellular processes related to those genes mainly display disturbances of EIF2 signaling common to G2019S LRRK2 mutation carriers and sporadic patients. These data pinpoint potential perturbations of translation and RNA splicing both related to RNA metabolism. Involvement of RNA metabolism is also observed in peripheral blood mononuclear cells of Parkinson’s disease patients carrying mutations of ATXN2 gene encoding for ataxin-2 protein. It is mainly known as a regulator of the stability, the splicing and the translation of mRNA. Such RNA-mediated perturbations seem to be a common to all forms of Parkinson’s disease and might be a physiological mechanism of the disease. RNAseq data from Parkinson’s disease patients having or not deleterious mutations are in agreement with this hypothesis showing quantitative and qualitative discrepancies of splicing variants inside genes involved in RNA metabolism but also in known molecular pathways of the disease.As a conclusion, our results support the current view of RNA metabolism association with neurodegenerative disorders. In Parkinson’s disease, those alterations could involve quantitative and qualitative variations of splicing variants inside genes involved in RNA metabolism but also in known perturbed molecular pathways of the disease. Further analyses of these dysregulations should be helpful to determine their specificity and evaluate their potential as biomarkers and therapeutic targets.
160

Pushing the boundaries of condensed matter electron momentum spectroscopy

Bowles, Cameron Michael Albert, cameronbowles@hotmail.com January 2008 (has links)
An electron momentum spectrometer at the Australian National University has been used to study various aspects of different solid state systems. EMS is a transmission mode technique and involves the collision of the incident electron with a bound electron, after which both electrons are ejected and measured in coincidence. Through well defined reaction kinematics the complete valence spectral momentum density A(ɛ,q) can be measured. The spectrometer has been used to measure the spectral momentum densities (spectral functions) of single crystal targets, as well as targets in disordered states. A new spin polarised electron source was constructed and implemented in the ANU spectrometer, which was used to measure spin dependent features of ferromagnetic samples.¶ This thesis is divided into seven chapters, the first chapter is an introduction into the field of electron momentum spectroscopy, highlighting what has been measured before and how the technique has progressed to its present state. Some comparisons to other experimental techniques will be made.¶ The second chapter describes the ANU EMS spectrometer in detail. The technique requires some technical and advanced equipment that is often used in novel ways. The production of thin (20 nm) free standing targets will be detailed, along with the experimental chamber and electronics used to run the apparatus and collect data. The determination of the energy and momentum resolution of the experiment is also described.¶ The third chapter will detail the design and construction of the new spin polarised electron source. The results of commissioning and characterizing the new source will be presented.¶ Chapters four through six will present the measured results. The fourth chapter will detail the single crystalline measurements for the group eleven noble metals (Cu, Ag and Au). Each sample was measured along three high symmetry directions and compared to a DFT calculation using the LDA and a FP-LMTO basis. The fifth chapter will include the results from samples that were in disordered states, a measurement which is unique to the EMS technique. The polycrystalline and amorphous states of the Si and Ge semiconductors are presented and conclusions are made to the degree of difference in the results and to which theoretical approach to the unique amorphous state of the semiconductors best matches the EMS results. The sixth chapter includes results of ferromagnetic iron, measured using the spin polarised electron source. The spectrometer was used to measure spin-polarised electron-energy-loss-spectroscopy (SPEELS) and magnetic electron-Compton profiles. A theoretical investigation is also presented in chapter six which details the advancements required in the spin polarised electron gun to measure an accurate spin-polarised EMS spectra of a ferromagnetic Fe sample.¶ Chapter 7 includes the summary of all the results presented and conclusions reached from the comparison of the measured EMS spectra and various theoretical calculations. A discussion is presented about the future directions and possibilities of the EMS technique.

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