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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.
351

Diagnostico de lesoes da tireoide pela espectroscopia de absorcao no infravermelho por tranformada de Fourier-FTIR / Thyroid lesions diagnosis by Fourier transformed infrared absorption spectroscopy (FTIR)

ALBERO, FELIPE G. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:27:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:37Z (GMT). No. of bitstreams: 0 / Os nódulos de tireóide constituem patologia comum, com uma incidência entre 4- 7% na população brasileira. Embora a punção aspirativa por agulha fina (PAAF) seja um método com boa sensibilidade, a discriminação entre lesões benignas e neoplasias malignas não é possível em todos os casos, permitindo a incidência de diagnósticos falsos-positivos, o que conduz a tireoideotectomia pelo risco de carcinoma. O escopo deste estudo foi verificar se a espectroscopia de absorção no infravermelho por transformada de Fourier (FTIR) pode contribuir no diagnóstico diferencial entre neoplasias malignas e benignas de tecidos e aspirados. Amostras de PAAF, homogenatos e tecidos de nódulos de tireóide com o diagnóstico histopatológico foram obtidos e preparados para análise espectroscópica por FTIR. As punções e homogenatos foram medidas por -FTIR (entre 950 1750 cm-1, com resolução de 4 cm-1 e 120 varreduras). As amostras de tecido foram analisadas diretamente pela técnica de ATR-FTIR, com resolução de 2 cm-1, 60 varreduras, região entre 950 1750 cm-1.. Todos os espectros foram corrigidos pela linha base e normalizados pela área sob a banda das amidas (1550-1640 cm-1) de modo a minimizar as variações de homogeneidade das amostras. Os espectros foram então convertidos em segundas derivadas usando-se o filtro de Savitzk-Golay com 13 pontos na janela. A variância de Ward e distância euclidiana foram usadas para se processar a análise de clusters. As amostras de PAAF revelaram um complexo padrão espectral. Todas as amostras mostraram alguns aglomerados de células ou grande concentração de hormônios, tendo representação em algumas bandas em 1545 e 1655 cm-1. Foram também encontradas bandas em torno de 1409, 1412, 1414, 1578 and 1579 cm-1, indicando a possível presença de açúcares, DNA e ácido cítrico de produtos metabólitos. Neste estudo, foi obtida uma excelente separação entre bócio adenomatoso e neoplasias malignas para as amostras de tecido, com 100% de sensibilidade em determinado cluster, mas 67% no geral e 50% de especificidade. Nos homogenatos e aspirados este valor foi menor (76,2% de sensibilidade e 52,6% de especificidade) porque incluiu outros tipos de lesões. Para uma maior diferenciação das amostras de PAAF de padrão folicular, um maior número de amostras se faz necessário. Os resultados deste estudo sugerem que a espectroscopia FTIR pode ser útil na diferenciação de carcinomas da tiróide em amostras de tecidos. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
352

La formation à l'autonomisation de l'enseignant de français en contexte lusophone : le cas du Cap-Vert / The empowering process of the French teacher in a portuguese-speaking context : the case of Cape Verde

Soares, Filipa 11 July 2014 (has links)
La problématique de cette recherche porte sur l'autonomisation des enseignants de français en poste dans les institutions d'enseignement secondaire au Cap-Vert. L'auteure se base sur des enquêtes de terrain auprès d'enseignants de français et d'acteurs sociaux concernés par l'enseignement-apprentissage du français ; sa recherche-action s'articule autour de quatre chapitres où le premier expose ses choix méthodologiques et son positionnement interne et externe comme enseignante-chercheur.Le second chapitre a pour finalité de présenter le contexte général de la recherche en mettant en avant l'importance du concept d'autonomie pour comprendre l'archipel créolophone et lusophone du Cap-Vert, dans une perspective historique et sociolinguistique. Le troisième chapitre fournit des éléments sur l'évolution générale du dispositif d'enseignement-apprentissage et sur la formation des enseignants de français, et repère trois types de formateurs que l'auteure regroupe sous le nom de "mentors d'autonomie" parce que leurs fonctions officielles visent à développer l'autonomie. Ce sont : le tuteur et le coordinateur (lycée) ; le superviseur (université publique du Cap-Vert). L'analyse détaillée des pratiques des enseignants de français et des mentors d'autonomie permet de dégager des indicateurs d'autonomie ou de non autonomie au niveau secondaire. Le quatrième et dernier chapitre dégage, à partir des deux chapitres précédents, des suggestions qui pourraient contribuer à remédier aux problèmes observés afin d'améliorer la qualité de l'enseignement du français dans le contexte capverdien. / This research intends to study the empowering process of the French teachers at the secondary level in the creole and portuguese-speaking archipelago of Cape Verde.The author investigates the field among teachers of French and social actors implicated in the French language teaching and learning. Her action-research is built upon four chapters among which the first chapter exposes her methodological options and her inner and outer position as a professor-researcher.The second chapter aims to present the general context of the research, pointing out how important the concept of autonomy is to understand the arquipelago of Cape Verde, in a historical and sociolinguistical perspect.The third chapter gives elements of information about the global evolution of the education system and of the training of the French teachers, and detects three trainers the author called « autonomy mentors » because their official functions would be to develop the autonomy : they are the advisory tutor and the coordinator (high school level) and the supervisor (public university of Cape Verde). Useful indicators of autonomy or non autonomy at the secondary level have been drowned from a detailed analysis of the teaching practices of the French teachers and of the « Mentors ».In the fourth and last chapter the conclusions of the two previous chapters are used to make suggestions which could help to solve the problems observed, in order to improve the quality of the secondary level French language teaching and learning in the Cape-Verdean context.
353

Water scarcity-induced change in vegetation cover along Teesta River catchments in Bangladesh : NDVI, Tasseled Cap and System dynamics analysis

Rahman, Md. Azizur January 2013 (has links)
Water scarcity is both natural and man-made phenomenon. Water control and uneven distribution of upstream TeestaRiver water makes artificial scarcity in downstream areas which can be minimized at least to the water stress level by balancing distribution and sustainable water use. Tasseled Cap transformation and NDVI methods were used in this study in order to find the magnitude of water scarcity in the downstream areas. NDVI and Tasseled Cap Greenness methods were applied to get proxy for soil moisture values in the form of biomass content and Tasseled Cap Wetness method were used to detect change in soil moisture content from Landsat TM and ETM+ data (1989-2010). System dynamic analysis method was applied to identify temporal and spatial differences between supply and demand of water in the TeestaRiver catchments area in the northwestern part of Bangladesh. It was found that, the vegetation cover and soil moisture content changed and shifted over time. Overall vegetation declined between 1989 and 2010 and soil moisture content also turned down. Moreover, TeestaRiver water is playing an important role for maintaining the balance between water supply and water scarcity in this region. There is a correlation between water scarcity in the downstream and availability of water in the TeestaRiver during dry seasons. / Master's Thesis
354

Especiação de compostos de enxofre, níquel e vanádio em cimento asfáltico de petróleo (CAP) e sua relação com os processos de envelhecimento / Speciation of sulphur, nickel and vanadium compounds in petroleum asphalt cement (CAP) and its relationship with aging process

Sant ana, Carla Simone 27 October 2015 (has links)
The speciation of sulfur compounds in CAP is very important, considering that these compounds are responsible for oxidation processes in asphalt binders, modifying their chemical and physical characteristics. The aim of this work was focused on chemical speciation of sulfur compounds in virgin and aged CAP samples (methods RTFOT, RTFOT/PAV, and RTFOT/SUNTEST) and their maltenic fractions. The separation of sulfur classes were carried out using the method developed by Payzant, which employs specific oxidation reactions and chromatographic separation on silica columns. The studied sulfur compound classes were the following: aromatic/saturated sulfur, aliphatic sulfides, thiophenes and sulfoxides. For this purpose, 6 samples were comparatively analyzed in virgin and aged CAP regarding the distribution of sulfur compounds in the three obtained fractions, where total sulfur was determined in order to observe the compounds behavior in the fractions after different aging processes. After speciation of the compounds, it was observed that the aging process occurs with structural changes in CAP, which involved the break and opening of thiophenic rings and the consequent formation of new S-compounds of high molecular weight. Sulfur compounds in form of sulfoxides increased after aging by RTFOT and RTFOT/PAV. Nickerl and vanadium were also analyzed in the studied samples by GFAAS (maltenic and asphaltenic fractions), since these species are involved in the aging process in CAP. The distribution of Ni and V in asphaltenic and maltenic fractions showed a diminishing of contents of the metals due to the lost by volatilization as metalloporphyrins. Correlating the chemical and physical changes observed in CAP, the variation in viscoelastic properties (G*/sin) may be a reflect of alterations in thiophenic fractions; additionally, variations in the penetration point may be related with the variation in asphaltenes and sulfur compounds of acid/basic characters, what may also be related to the viscoelastic changes in CAP. Based on the obtained results, this work aimed to answer 6 main guiding questions of the thesis: (1) which transformations occur in the speciation of sulfur compounds with the CAP aging after short-term, long-term and UV radiation processes?; (2) what is the major class of sulfur compounds in CAP and how it changes with the aging process?; (3) which transformations occur in the metals nickel and vanadium with CAP aging after short-term, long-term and UV radiation processes?; (4) the forced aging processes for CAP (RTFOT, PAV and SUNTEST) lead to different chemical transformations in asphaltenes and maltenes?; (5) what are the correlations existing between the chemical and physical changes in CAP, from the chemical speciation and rheology after aging process?; (6) is it possible to establish some chemical reactivity order for CAP based on the chemical speciation and rheology after aging process? / A especiação de compostos sulfurados em CAP é de grande importância, uma vez que alguns desses compostos são responsáveis pela oxidação de ligantes asfálticos, modificando suas características químicas e físicas. Este trabalho tem como foco a especiação química de classes majoritárias de compostos sulfurados em amostras de CAP virgem e envelhecidas (métodos RTFOT, RTFOT+PAV e RTFOT+SUNTEST) e suas respectivas frações maltênicas. A especiação das classes sulfuradas foi realizada pelo método adaptado de Payzant empregando reações de oxidação específicas e separações cromatográficas por adsorção em sílica. Os teores de sulfóxidos foram obtidos por FTIR, utilizando-se como padrão de sulfóxidos uma solução de referência de tetrametileno sulfóxido (TMSO) em diclorometano. As classes de compostos estudadas foram: sulfurados aromáticos/saturados, tiofenos, sulfetos alifáticos e sulfóxidos. Para isso, foram analisadas comparativamente 6 amostras de CAP virgem e envelhecidas em relação à distribuição dos compostos sulfurados nas três frações obtidas, onde foram analisados os teores de enxofre total a fim de se observar o comportamento dos compostos nessas frações nos diferentes processos de envelhecimento. Com base nesses resultados, observa-se que no processo de envelhecimento ocorrem mudanças estruturais envolvendo quebras de ligações em anéis tiofênicos e formação de novas classes de compostos sulfurados de maior peso molecular. Os compostos de enxofre na forma de sulfóxidos apresentaram um aumento decorrente dos processos de envelhecimento para os envelhecimentos RTFOT e RTFOT/PAV. Também foram analisados os teores de Níquel e Vanádio nas diferentes amostras, em suas frações maltênicas e asfaltênicas por GFAAS, já que estes metais são envolvidos como coadjuvantes no processo de envelhecimento dos CAPs. A distribuição dos metais de Ni e V nas frações asfaltênicas e maltênicas sofreu uma diminuição nos teores destes metais decorrente das perdas por volatilização na forma de metaloporfirinas. Correlacionando-se as alterações químicas e físicas observadas em CAP, as variações nas propriedades viscoelásticas (G*/sin) podem ser um reflexo das alterações que ocorrem nas frações tiofênicas; além disso, a variação no aumento da penetração pode estar relacionada com a variação do teor de asfaltenos e de compostos de caráter e básico, que também podem ser relacionados com as mudanças viscoelásticas dos CAPs. Com base nos resultados obtidos, esse trabalho buscou responder a 6 perguntas principais e norteadoras da tese apresentada: (1) que transformações ocorrem na especiação de compostos de enxofre com o envelhecimento de CAP em curto prazo, longo prazo e sob ação da radiação UV?; (2) qual a classe majoritária de compostos de enxofre em CAP e como esta se altera com o envelhecimento?; (3) que transformações ocorrem nos metais níquel e vanádio com o envelhecimento de CAP em curto prazo, longo prazo e sob ação da radiação UV?; (4) os processos de envelhecimento forçado de CAP (RTFOT, PAV e SUNTEST) conduzem a transformações químicas diferentes em asfaltenos e maltenos?; (5) quais as correlações existentes entre as transformações químicas e físicas em CAP, a partir da especiação química e da reologia após o envelhecimento?; (6) é possível estabelecer alguma ordem de reatividade química para o CAP com base na especiação química e na reologia após o envelhecimento?
355

Requirements for ARS2 in RNA processing and retina development

O'Sullivan, Connor 02 September 2016 (has links)
ARS2 is a stable component of the nuclear cap-binding complex (CBC) and is critical for RNA Polymerase II transcript processing. As such, ARS2 functions in numerous RNA Polymerase II transcript processing events, which happen co-transcriptionally from initiation to termination, and post-transcriptionally during maturation and export into the cytoplasm. Developmentally, ARS2 is essential for stem cell maintenance and differentiation during embryogenesis and in neural stem cells. Two major questions in the field were: 1) how does ARS2 function in stem cell maintenance and/or differentiation? and 2) how does ARS2 distinguish between disparate RNA classes and processing complexes? In chapter 2, I show that ARS2 is required for the proliferation and cell fate decisions of progenitors in the mouse retina. Specifically, ARS2 knockdown delays cell cycle progression and leads to premature cell cycle exit. Additionally, ARS2 knockdown increases the proportion of cells expressing rod photoreceptor marker Nrl, and decreases Müller glial marker expression. Similarly, knockdown of FLASH, an essential component for replication-dependent histone transcript processing and cell cycle progression, increases the proportion of cells expressing the Nrl reporter, suggesting ARS2’s role in histone processing is contributing to cell cycle progression and fate specification in the developing retina. In chapter 3, I used bioinformatics analysis and homology modeling to classify four structural domains of mammalian ARS2, including a newly identified RNA recognition motif (RRM), and performed mutagenesis to assess their functions. The unstructured C-terminus is required for interaction with the CBC, the Mid domain is implicated in binding DROSHA, which is required for microRNA biogenesis, while the zinc finger and RRM are involved in binding FLASH. Moreover, the zinc finger is required for interacting with RNA. Collectively, this work establishes a model where ARS2 acts as a scaffold, using multiple domains to interact with distinct processing complexes in a mutually exclusive manner. It is also the first study describing the requirements of ARS2 in the developing retina. Understanding the molecular mechanisms governing progenitor proliferation and cell fate specification is crucial in order to design therapies for retinal degenerative diseases. / Graduate / 0487
356

Predikce dopadů aukcí emisních povolenek na státní rozpočet ČR / Forecasting the impact of auctioning of emission allowances on the state budget of the Czech Republic

Hanák, Ondřej January 2017 (has links)
The increasing volume of greenhouse gases in the atmosphere has led to the creation of European Emissions Trading System (EU ETS). This system should also fulfil an incentive function to reduce emissions. The EU ETS also participates in revenues of the state budgets. This master thesis deals with impacts of EU ETS on revenues of state budgets for each member states of this system. The thesis is compiled with calculations of revenues of state budgets. This methodology is then applied to the assessment of the impact of auctioning of emission allowances on the Czech state budget and is demonstrated on three possible scenarios.
357

Řízení změny a související vliv na oblast IS/ICT / Change management and related influence on IS/ICT

Kroupa, Filip January 2012 (has links)
The topic of this thesis is change management. A summary of the topic is made in the first part of this thesis so that a reader has the theoretical background to read further. In the second part, the author describes five most important change management methods. These methods are described, analyzed and compared to one another. Five hypotheses about the most influential factors to the outcome of a change project were created out of the analysis. These hypotheses cover the entire span of a typical change project and are tested in the practical part of this thesis. The practical part of the thesis relies on a thorough case studies analysis and interviews. By analyzing the case studies and the interviews, the author was able to judge the validity of set hypotheses and create a set of recommendations for future change projects. These recommendations are based on many real situations and therefore are valuable for future reference. The role of information technology in change management is also emphasized at the end of the thesis.
358

Análisis de procesos de transcripción, traducción y degradación del virus del arabesco del Pelargonium

Blanco Pérez, Marta 08 February 2017 (has links)
[EN] Pelargonium line pattern virus (PLPV) is one of the most frequent viral agents in geranium. It's an icosahedral virus, with a monopartite, positive-sense, single-stranded RNA genome, lacking a cap structure at the 5' end and poly(A) tail at its 3' end. Its genomic RNA (gRNA) contains five genes that encode two proteins involved in replication, two proteins involved in movement, (MP1 and MP2), and a coat protein (CP) that also acts as viral suppressor of RNA silencing. The first two genes are translated from the gRNA whereas the remaining three are translated from the single subgenomic RNA (sgRNA) that the virus produces during infection. The PLPV belongs to the family Tombusviridae and presents unique characteristics such as: i) production of a sole sgRNA that is structural and functionally tricistronic, ii) presence of a non-AUG start codon (CUG or GUG) initiating the MP2 ORF, iii) absence of AUG codons in any frame between the AUG initiation codons of MP1 and CP genes, and iv) sequence-based phylogenetic clustering of all encoded proteins in separate clades from those of other family members. In this doctoral thesis we have tried, on the one hand, to further study the regulation of PLPV gene expression and, on the other hand, to obtain information on degradation processes to which its genome is subjected, particularly on those related to the mechanism of RNA silencing. The first objective in this work was to determine the mechanism and the viral RNA elements involved in the generation of the sgRNA of PLPV. An RNA-RNA interaction involving distant segments of the gRNA of plus polarity has been identified. Such long-range interaction seems to act in cis and specifically mediates the production of the negative strand of the sgRNA, a type of molecule easily detectable in infected tissue. These results together with the possibility of uncoupling the synthesis of negative and positive strands of the sgRNA and with the observation of sequence similarity between the 5' ends of the gRNA and the sgRNA (with promoter function in their complementary strands), suggest that PLPV follows a model of premature termination for the formation of its unique sgRNA. The second objective of this work was to identify the elements of the viral genome that are involved in its translation through a cap-independent mechanism. Transfection of N. benthamiana protoplasts with PLPV-based reporter constructs has allowed us to corroborate the functionality of the CITE in the context of both the gRNA and the sgRNA. Additionally, it has been shown that this element establishes a long-distance RNA-RNA interaction with the 5'-region of the corresponding RNA which is essential for its activity. Moreover, data that support the relevance of the CITE during the infectious cycle of the virus have been obtained. Finally, in order to gain information on the role of PLPV as inducer and target of RNA silencing that the plant triggers as a defense against the virus, we have characterized the viral small RNAs (vsRNAs) present in PLPV-infected N. benthamiana plants. High-throughput sequencing, computational analysis and molecular hybridization assays have shown that: i) vsRNAs of the PLPV accumulate in extraordinarily high proportions in infected tissue, ii) 21 and 22 nt vsRNAs are the most frequent ones, iii) the vsRNAs of positive and negative polarities are in similar proportions, and, iv) there is variability in the vsRNAs 5'-proximal nucleotide. These results have provided clues on the viral molecules that must act as substrates for the formation of the vsRNAs and, also, about the components of the silencing machinery of the host that are likely involved in the response against the virus. / [ES] El virus del arabesco del Pelargonium (PLPV) es uno de los agentes virales más frecuentes en geranio. Se trata de un virus icosaédrico, con un genoma monopartito de RNA de simple cadena y de polaridad positiva que carece de estructura cap en su extremo 5' y de cola poli(A) en su extremo 3'. Su RNA genómico (gRNA) contiene 5 genes que codifican dos proteínas implicadas en replicación, dos proteínas implicadas en movimiento, (MP1 y MP2), y una proteína de cubierta (CP) que funciona además como supresor del silenciamiento por RNA. Las dos primeras se traducen a partir del gRNA y las tres restantes lo hacen a partir de un único RNA subgenómico (sgRNA) que el virus produce en el curso de la infección. El PLPV pertenece a la familia Tombusviridae y presenta características peculiares como son: a) la generación de un solo sgRNA estructural y funcionalmente tricistrónico, b) la presencia de un codón de iniciación no canónico (CUG o GUG) en el gen de la MP2, c) la ausencia de codones AUG en cualquier pauta de lectura entre los codones de inicio AUG de los genes MP1 y CP, y d) la agrupación filogenética en un clado separado de otros miembros de la familia Tombusviridae. En esta tesis se ha pretendido, por una parte, profundizar en el estudio de las estrategias de regulación de la expresión génica del PLPV y, por otra, recabar información sobre los procesos de degradación a los que se encuentra sometido su genoma, particularmente sobre aquellos relacionados con el mecanismo de silenciamiento por RNA. El primer objetivo abordado en este trabajo ha sido determinar el mecanismo y los elementos del RNA viral implicados en la generación del sgRNA del PLPV. Se ha identificado una interacción entre segmentos alejados del gRNA de polaridad positiva, que actúa en cis y que media la producción de la cadena negativa del sgRNA, un tipo de molécula fácilmente detectable en tejido infectado. Estos resultados junto con la posibilidad de desacoplar la síntesis de cadenas negativas y positivas del sgRNA y con la observación de similitud de secuencia entre el extremo 5' del gRNA y del sgRNA (con una función promotora en las cadenas complementarias), sugieren que el PLPV sigue un modelo de terminación prematura para la formación de su único sgRNA. El segundo objetivo de este trabajo ha sido identificar los elementos del genoma viral que están implicados en su traducción a través de un mecanismo independiente de cap. Mediante trasfección de protoplastos de N. benthamiana con construcciones delatoras, se ha corroborado la presencia de un estimulador traduccional (CITE) tanto en el contexto del gRNA como del sgRNA. Adicionalmente, se ha constatado que este elemento establece una interacción RNA-RNA a larga distancia con la región 5' del RNA correspondiente que es esencial para su actividad. Asimismo, se han obtenido datos que apoyan la relevancia del CITE durante el ciclo infeccioso del virus. Por último, para intentar recabar información sobre el papel del PLPV como inductor y diana de mecanismos de silenciamiento por RNA disparados por la planta como defensa frente al virus, se han caracterizado los pequeños RNAs virales (vsRNAs) presentes en plantas de N. benthamiana infectadas. Mediante secuenciación masiva, análisis computacionales e hibridación molecular, se ha podido determinar que: a) los vsRNAs del PLPV se acumulan en proporciones extraordinariamente elevadas en tejido infectado, b) los vsRNAs de 21 y 22 nt son los mayoritarios, c) los vsRNAs de polaridad positiva y negativa están en proporciones similares, y d) existe variabilidad en el nucleótido 5'-proximal de los vsRNAs. Estos resultados han permitido obtener pistas acerca de las moléculas virales que deben actuar cómo sustratos para la formación de los vsRNAs y, también, acerca de los componentes de la maquinaria de silenciamiento del huésped que deben participar en la respuesta del mismo frente al virus. / [CAT] El virus de l'arabesc del Pelargonium (PLPV) és un dels agents virals més freqüents en gerani. Es tracta d'un virus icosaèdric, amb un genoma monopartit de RNA de simple cadena i de polaritat positiva que manca d'estructura cap en el seu extrem 5', i de cua poli(A) en el seu extrem 3'. La seua RNA genòmic (gRNA) conté 5 gens que codifiquen dues proteïnes implicades en replicació, dues proteïnes implicades en moviment, (MP1 i MP2), i una proteïna de coberta (CP) que funciona a més com supresor del silenciamiento per RNA. Les dues primeres es tradueixen a partir del gRNA i les tres restants ho fan a partir d'un únic RNA subgenómico (sgRNA) que el virus produeix en el curs de la infecció. El PLPV pertany a la família Tombusviridae, i presenta característiques peculiars com són: a) la generació d'un sol sgRNA estructural i funcionalment tricistrònic, b) la presència d'un codó d'iniciació no canònic (CUG o GUG) en el gen de la MP2, c) l'absència de codons AUG en qualsevol pauta de lectura entre els codons d'inici AUG dels gens MP1 i CP, i d) l'agrupació filogenètica en un clade separat d'altres membres de la família Tombusviridae. En aquesta tesi s'ha pretès, d'una banda, aprofundir en l'estudi de les estratègies de regulació de l'expressió gènica del PLPV i, per una altra, recopilar informació sobre els processos de degradació als quals es troba sotmès el seu genoma, particularment sobre aquells relacionats amb el mecanisme de silenciament per RNA. El primer objectiu abordat en aquest treball ha sigut determinar el mecanisme i els elements del RNA viral implicats en la generació del sgRNA del PLPV. S'ha identificat una interacció entre segments allunyats del gRNA de polaritat positiva, que actua en cis i que intervé en la producció de la cadena negativa del sgRNA, un tipus de molècula fàcilment detectable en teixit infectat. Aquests resultats juntament amb la possibilitat de desacoblar la síntesi de cadenes negatives i positives del sgRNA i amb l'observació de similitud de seqüència entre l'extrem 5' del gRNA i del sgRNA (amb una funció promotora en les cadenes complementàries), suggereixen que el PLPV segueix un model de terminació prematura per a la formació del seu únic sgRNA. El segon objectiu d'aquest treball ha sigut identificar els elements del genoma viral que estan implicats en la seua traducció a través d'un mecanisme independent de cap. Mitjançant trasfección de protoplastos de N. benthamiana amb construccions delatores, s'ha corroborat la presència d'un estimulador traduccional (CITE) tant en el context del gRNA com del sgRNA. Addicionalment, s'ha constatat que aquest element estableix una interacció RNA-RNA a llarga distància amb la regió 5' del RNA corresponent que és essencial per a la seua activitat. Així mateix, s'han obtingut dades que recolzen la rellevància del CITE durant el cicle infecciós del virus. Finalment, per intentar recopilar informació sobre el paper del PLPV com inductor i diana de mecanismes de silenciament per RNA disparats per la planta com a defensa davant del virus, s'han caracteritzat els xicotets RNAs virals (vsRNAs) presents en plantes de N. benthamiana infectades. Mitjançant seqüenciació massiva, anàlisis computacionals i hibridació molecular, s'ha pogut determinar que: a) els vsRNAs del PLPV s'acumulen en proporcions extraordinàriament elevades en teixit infectat, b) els vsRNAs de 21 i 22 nt són els majoritaris, c) els vsRNAs de polaritat positiva i negativa estan en proporcions similars, i d) existeix variabilitat en el nucleòtid 5'-proximal dels vsRNAs. Aquests resultats han permès obtenir pistes sobre les molècules virals que han d'actuar com substrats per a la formació dels vsRNAs i, també, sobre els components de la maquinària de silenciament de l'hoste que han de participar en la resposta del mateix enfront del virus. / Blanco Pérez, M. (2016). Análisis de procesos de transcripción, traducción y degradación del virus del arabesco del Pelargonium [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63452 / TESIS
359

Výroba náhradního dílu čerpadla pro řezání vodním paprskem / Production of replacement part for pump of waterjet cutter

Vrána, Lukáš January 2012 (has links)
The thesis contains a theoretical part dealing with non-conventional water jet technologies. The first part deals with analysis of water jet technology and possible uses for machining operations. The practical part deals with the issue part of the pump and its possible production process. The conclusion is technical-economically evaluation.
360

Investigating ways to reduce greenhouse gas emissions by means of tax measures

Stols, Gerhardus Petrus 10 September 2010 (has links)
The objective of this study is to restrict the emission of greenhouse gasses by investigating if this objective would be reached by the implementation of a tax. Global warming is caused by the emission of greenhouse gasses into the atmosphere. In order to restrict global warming it is necessary for individuals and entities to act in a more environmentally friendly manner and to emit less greenhouse gasses. A further objective of this study is to investigate various measures that can be used as an incentive to restrict the emission of greenhouse gasses. This study found that the main emitters of greenhouse gasses are power stations, industries and the transport sector. This study will therefore focus on the reduction of greenhouse gasses in these areas. The way to identify methods used to reduce greenhouse gas emissions, is to investigate the techniques that first world countries use to reduce greenhouse gas emissions, to judge the level of success they achieved and to compare their methods to the definition of a “good tax”. It was found that “cap-and-trade” is a better model than carbon tax for the reduction of greenhouse gas emissions by power stations and industries. It was also found that a combination between a tax on fuel and a tax calculated on greenhouse gas emissions per kilometre for each individual vehicle will result in the greatest reduction in the emission of greenhouse gasses produced by the transportation sector. AFRIKAANS : Die doelwit van hierdie studie is om die vrystelling van groenhuis uitlaatgasse te beperk deur ondersoek in te stel of die doelwit bereik kan word deur die implementering van 'n belasting. Globale aardverwarming word veroorsaak deur 'n oormaat vrystelling van groenhuisgasse in die atmosfeer. Om globale aardverwarming te beperk, sal individue, sowel as entiteite, meer omgewingsvriendelik moet optree deur minder groenhuisgasse vry te stel. 'n Verdere doelwit van hierdie studie is om verskeie metodes, insluitende belasting, te ondersoek waardeur die vrystelling van groenhuisgasse verminder kan word. In die studie is vasgestel dat kragstasies, industrieë en vervoerstelsels die hoofvrystellers van groenhuisgasse is. Die fokus van die studie is dus gerig op die vermindering van groenhuisgasvrystelling spesifiek in hierdie areas. Die wyse om metodes, wat gebruik word om groenhuisgasvrystellings te verminder, te identifiseer, is om die tegnieke wat in eerste wêreldlande gebruik word te ondersoek, om die vlak van sukses wat daarmee bereik word, te bepaal en om daardie metodes teen die definisie van 'n “goeie belasting” te toets. Daar is gevind dat “uitlaatgas handel” 'n beter model is as koolstofdioksiedbelasting ten einde 'n vermindering van groenhuisgasvrystellings deur kragstasies en industrieë te bewerkstellig. Daar is ook gevind dat ‘n kombinasie van ‘n belasting op brandstof en ‘n belasting bereken op groenhuisgasvrystellings per kilometer van elke individuele voertuig die grootste vermindering in groenhuisgasvrystellings in die vervoerstelsel sal meebring. Copyright / Dissertation (MCom)--University of Pretoria, 2010. / Taxation / unrestricted

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