Submitted by Cristiane Oliveira (cristiane.oliveira@fgv.br) on 2011-06-03T18:55:36Z No. of bitstreams: 1 66080100276.pdf: 780580 bytes, checksum: 59e34371f81f676e674a30d3b513d3d8 (MD5) / Approved for entry into archive by Vera Lúcia Mourão(vera.mourao@fgv.br) on 2011-06-03T19:22:58Z (GMT) No. of bitstreams: 1 66080100276.pdf: 780580 bytes, checksum: 59e34371f81f676e674a30d3b513d3d8 (MD5) / Approved for entry into archive by Vera Lúcia Mourão(vera.mourao@fgv.br) on 2011-06-03T19:24:09Z (GMT) No. of bitstreams: 1 66080100276.pdf: 780580 bytes, checksum: 59e34371f81f676e674a30d3b513d3d8 (MD5) / Made available in DSpace on 2011-06-03T19:25:28Z (GMT). No. of bitstreams: 1 66080100276.pdf: 780580 bytes, checksum: 59e34371f81f676e674a30d3b513d3d8 (MD5) Previous issue date: 2011-01-11 / The purpose of this study is to estimate the impact of brazilian corporate issues in USD on Cupom Cambial. We can view Cupom Cambial, under Cover Interest Parity (CIP), as a result of two components: Risk-free rate (Libor) and Country Risk. Additional deviations from CIP can be explained by several factors such as transactions costs, liquidity, arbitrage flows from financial and non-financial companies, etc. In this context, the arbitrage occurs when it becomes possible for a brazilian company to issue external debt and bring this resources to Brazil, finding a final rate in BRL lower than local loans (via debêntures, loans, CD’s, etc), all in. Given the necessary conditions for this type of trade, the effect can be seen in Cupom Cambial market via abnormal flow of sellers. Non-parametric tests (Wilcoxon-Mann-Whitney, Kruskal-Wallis e Van der Waerden) and event study methodology found abnormal behavior in FRA of Cupom Cambial (FRC) market during the event window, where the events are the issues of external debt of Brazilian companies, excluding country risk and Libor from FRC changes. To estimate the impact of corporate issues through FRA of cupom cambial, we used two econometric models, AR-GARCH and OLS with Newey-West correction. The results are that brazilian corporate issues cause tightening of 2-5 bps in FRC, depending on the maturity of the issue and the model used. Using the same methodology we concluded that each USD 100 million issue are responsible, on average, for 1 bps tightening in FRC. / Este estudo tem por objetivo estimar o impacto do fluxo de emissões corporativas brasileiras em dólar sobre o cupom cambial. Podemos entender o cupom cambial, sob a ótica da Paridade Coberta da Taxa de Juros, como resultado de dois componentes: Taxa de juros externa (Libor) e Risco País. Desvios adicionais sobre a Paridade podem ser explicados por diversos fatores como custos de transação, liquidez, fluxos em transações de arbitragem de empresas financeiras ou não-financeiras, etc. Neste contexto, os fluxos de arbitragem ocorrem quando é possível para uma empresa brasileira captar recursos no mercado externo e internar estes recursos no Brasil encontrando uma taxa final de captação em reais inferior à de sua captação local (via debêntures, notas financeiras, empréstimos, CDB’s, etc) incluindo todos os custos. Quando há condições necessárias a este tipo de operação, o efeito pode ser visto no mercado de FRA de cupom cambial da BM&F, através de um fluxo anormal de doadores de juros. Testes não-paramétricos (Wilcoxon-Mann-Whitney, Kruskal-Wallis e Van der Waerden) e a metodologia de estudo de eventos detectaram comportamento anormal no mercado de FRA de cupom cambial frente aos eventos aqui considerados como emissões de eurobonds de empresas brasileiras, excluindo o efeito do risco soberano, medido pelo CDS Brasil e considerando nulo o risco de conversibilidade no período, após análise do diferencial entre NDF onshore e offshore. Para estimação do impacto das emissões sobre o FRA de cupom cambial foram utilizados dois modelos, AR-GARCH e OLS com correção de Newey-West, e os resultados mostraram que as emissões causam fechamento de 2 a 5 bps no FRA de cupom cambial, dependendo do vencimento da emissão e do modelo avaliado. Sob a mesma metodologia, concluímos de cada USD 100 milhões de emissões são responsáveis por, em média, 1 bps de fechamento no FRA de cupom cambial, tudo mais constante.

Made available in DSpace on 2014-06-11T19:25:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-23Bitstream added on 2014-06-13T19:32:46Z : No. of bitstreams: 1 silveira_jb_me_ilha.pdf: 1625672 bytes, checksum: 5fb649c1f1320fe8b2df5942ab03558b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho visou a produção e o estudo das propriedades físicas de amostras de resina epóxi transparente dopadas com diferentes concentrações de nanocristais de sulfeto de cádmio (CdS). As técnicas de difração de raios-X, espectroscopia no infravermelho, espectroscopia Raman e calorimetria diferencial de varredura (DSC) foram utilizadas para estudar as propriedades estruturais. Espectroscopias de refletância e de transmitância foram utilizadas para obter a dispersão do índice de refração e do coeficiente de extinção na região do UV-Vis para amostras dopadas com diferentes concentrações de CdS. A técnica do ângulo de Brewster foi também utilizada para determinar o índice de refração das diferentes amostras. Os valores dos índices de refração obtidos através das medidas de refletância e de transmitância na região do UV-Vis e da técnica do ângulo de Brewster foram comparados e os resultados mostraram que a técnica do ângulo de Brewster além de apresentar valores que conferem com a literatura apresentou valores com alta precisão. Foram realizadas medidas de birrefringência opticamente. Foram obtidos resultados da birrefringência fotoinduzida por um fóton para diferentes concentrações de CdS por amostra e para diferentes intensidades da luz de excitação. Os resultados foram quantificados utilizando alguns dos principais modelos teóricos, onde foi observado que a resina epóxi pura apresenta birrefringência fotoinduzida e a adição do CdS contribui para o aumento da birrefringência. / The present work sought production and study of the physical properties of samples of transparent epoxy resin doped with different concentrations of structures of cadmium sulfide (CdS) nanocrystals. X-ray diffraction, infrared spectroscopy, Raman spectroscopy e differential scanning calorimetry techniques were used to study their structural properties. Reflectance and transmittance spectroscopy were used to obtain of the refraction index and of the extinction coefficients dispersion in the UVVis region for doped samples with different concentrations of CdS. The Brewster angle technique also was used to determine the refraction index of the different samples. The refraction index values obtained using the reflectance and transmittance measurement in the UV-Vis region and Brewster angle technique were compared and the results showed that the Brewster angle technique besides presents values that check with the literature, presented values with high precision. Measurements of optically induced birefringence were accomplished. Were obtained results of the photo induced birefringence by a photon for different concentrations of CdS for sample and for different intensities of the excitement light. The results were quantified using some of the principal theoretical models, where was observed that the pure epoxy resin presents photo induced birefringence and the addition of the CdS contributes to the increase of the birefringence.

Submitted by VICTOR TEODORO DE SOUSA null (vi_teo@hotmail.com) on 2018-02-28T05:32:11Z No. of bitstreams: 1 Dissertação Victor Teodoro.pdf: 643908 bytes, checksum: 97cadcb4cc71146e3fd3f83802590866 (MD5) / Approved for entry into archive by Satie Tagara (satie@marilia.unesp.br) on 2018-02-28T14:20:20Z (GMT) No. of bitstreams: 1 sousa_vt_me_mar.pdf: 643908 bytes, checksum: 97cadcb4cc71146e3fd3f83802590866 (MD5) / Made available in DSpace on 2018-02-28T14:20:20Z (GMT). No. of bitstreams: 1 sousa_vt_me_mar.pdf: 643908 bytes, checksum: 97cadcb4cc71146e3fd3f83802590866 (MD5) Previous issue date: 2018-01-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esta pesquisa objetiva compreender como o pensamento sobre questões internacionais desenvolvido pelo Partido dos Trabalhadores (PT) impactou na política externa do governo Lula da Silva (2003-2010). Utiliza-se as produções documentais resultantes dos Congressos, Encontros e Campanhas Presidenciais, produzidos pelo próprio partido entre os anos de 1979 e 2017, para analisar a evolução das discussões sobre a temática internacional. Apresenta-se, por meio de resenhas ano a ano, um panorama amplo sobre a evolução das bases programáticas do PT, evidenciando um processo de mudança identitária, ocorrida durante os anos de 1990 e culminando no início dos anos 2000. Esta mudança representa a ascensão de uma nova pauta em torno da liderança de Lula da Silva: o lulismo. A agenda desta corrente assume posição majoritária na condução do partido. Após a conquista da Presidência em 2002, esta influência é percebida sobre a atuação em política externa do governo. A ação assertiva e condicionantes de variadas matizes alçam o país a um certo protagonismo internacional e regional. O projeto de integração na América do Sul passa a ser um território de disputa entre dois modelos: o lulismo e o bolivarianismo chavista. Condicionantes conjunturais dão maior espaço à atuação brasileira na região. O país adota uma postura moderada e conciliatória no subcontinente sul-americano, ao passo que expressa uma posição reformista no plano internacional. Nesta seara são propostas as iniciativas da União de Nações Sul-Americanas (Unasul) e do Conselho de Defesa Sul-Americano (CDS), ambos em 2008. Dada a importância destes organismos para a integração sul-americana, analisamos o impacto das disputas entre os diferentes projetos políticos para a região e da política externa adotada pelo governo Lula para a integração em defesa. Conclui-se que a dinâmica de disputa regional impulsionou as iniciativas de integração, tendo um papel importante para a consolidação de um espaço de diálogo e concertação, representado por estes órgãos. O Brasil destaca-se como figura central neste processo, pela posição moderadora e pragmática que adotou e do projeto político interno que desenvolveu. / This research aims to understand how the thinking about international issues developed by Brazilian Workers' Party (PT) has impacted the foreign policy of Lula da Silva government (2003-2010). Documentary productions resulting from the National Conventions, Meetings and Presidential Campaigns produced by the party itself between 1979 and 2017 are used to analyze the evolving discussions on international thematic. An overview of evolving PT's programmatic bases is presented annually through reviews, evidencing a process of identity change that took place during the 1990s and culminating in the early 2000s. This change represents the rise of a new agenda around the leadership of Lula da Silva: the lulismo. The agenda of this internal trend takes a majority position in the board of the party. After winning the Presidency in 2002, this influence is perceived on the government’s foreign policy performance. By assertive action and constraints of different shades raise the country to a certain international and regional projection. The integration project in South America becomes a territory in the dispute between two models: lulismo and bolivarianismo. Situational factors give greater space to the Brazilian performance in the region. The country adopts a moderate and conciliatory stance in the South American subcontinent, while expressing a reformist stance on the international plane. In this environment, the initiatives for the Union of South American Nations (Unasur) and the South American Defense Council (SADC), both in 2008, are proposed. By the importance of these organizations for South American integration, we analyze the impact of disputes between the different political projects for the region and the foreign policy adopted by Lula government in defense integration. It is concluded that the regional dispute dynamics has boosted integration initiatives, playing an important role in the consolidation of a space to dialogue and consultation, represented by these bodies. Brazil stands out as a central figure in this process, for the moderating and pragmatic position it adopted and for the internal political project it developed. / Esta investigación objetiva comprender cómo el pensamiento sobre cuestiones internacionales desarrollado por el Partido de los Trabajadores brasileño (PT) impactó en la política exterior del gobierno Lula da Silva (2003-2010). Se utilizan los documentos resultantes de los Congresos, Encuentros y Campañas Presidenciales, producidos por el propio partido entre los años 1979 y 2017, para analizar la evolución de las discusiones sobre la temática internacional. Se presenta, por medio de reseñas año tras año, un panorama amplio sobre la evolución de las bases programáticas del PT, evidenciando un proceso de cambio de identidad ocurrido durante los años 1990 y culminando a principios de los años 2000. Este cambio representa la ascensión de una nueva pauta en torno al liderazgo de Lula da Silva: el lulismo. La agenda de esta corriente asume una posición mayoritaria en la conducción del partido. Después de la conquista de la Presidencia en 2002, esta influencia se percibe sobre la actuación en política exterior del gobierno. La acción asertiva y condicionantes de variadas matices alza al país a un cierto protagonismo internacional y regional. El proyecto de integración en América del Sur pasa a ser un territorio de disputa entre dos modelos: el lulismo y el bolivarianismo chavista. Los condicionantes coyunturales dan mayor espacio a la actuación brasileña en la región. El país adopta una postura moderada y conciliadora en el subcontinente sudamericano, mientras que expresa una posición reformista a nivel internacional. En este contexto se proponen las iniciativas de la Unión de Naciones Sudmericanas (UNASUR) y del Consejo de Defensa Sudamericano (CDS), ambas en 2008. Dada la importancia de estos organismos para la integración sudamericana, analizamos el impacto de las disputas entre los diferentes proyectos políticos para la región y la política exterior adoptada por el gobierno de Lula para la integración en defensa. Se concluye que la dinámica de disputa regional impulsó las iniciativas de integración, teniendo un papel importante para la consolidación de un espacio de diálogo y concertación, representado por estos órganos. Brasil se destaca como figura central en este proceso, por la posición moderadora y pragmática que adoptó y del proyecto político interno que desarrolló.

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas Gerais / A caracterização de materiais vítreos dopados tem sido uma área importante para o desenvolvimento de tecnologias fotônicas. Porém, com o desenvolvimento da nanociência e a descoberta das propriedades quânticas dos nanocristais, a quantidade de materiais vítreos a serem estudados aumentou de forma abrupta, o qual despertou um forte interesse da comunidade científica visando possíveis aplicações tecnológicas. O presente trabalho tem como objetivo investigar o índice de refração não linear da matriz vítrea a base de fosfato (P2O5 + AhO3 + Na2O + K2O) dopada com íons de neodímio e nanocristais de CdS. Destaca-se que a pesquisa corresponde à caracterização de uma matriz fosfata pouco conhecida na literatura, com dopantes de categorias distintas, sendo um Terra Rara e um nanocristal, nos quais apresentam picos de absorção próximos. Para a presente caracterização não linear, foi utilizada a técnica de Z-Scan, conhecido na literatura por sua simplicidade e precisão quando comparada com outras técnicas capazes de realizar a mesma medida. Medidas de absorção ótica e tempo de vida também foram feitas, pois fornecem parâmetros lineares para o cálculo das propriedades não lineares. Os resultados mostram que existe uma interação entre os dopantes, capaz de gerar uma variação nos parâmetros lineares e não lineares em estudo. / The characterization of doped glasses has been an important area for the development of photonic technologies. However, the development of nanoscience and the discovery of the quantic properties of nanocrystals, increased the number of researches in glass materials with interest in technological applications by the scientific community. This work aims to investigate the nonlinear refractive index of the phosphate glass matrix (P2O5 + Al2O3 + Na2O + K2O) doped with neodymium ions and CdS nanocrystals. This research characterizes a phosphate glass matrix, which is not well known in the literature with different dopants, in this case, rare earths and nanocrystals, which they show similar absorption peaks at ultraviolet. For a nonlinear optics characterization was used the Z-Scan technique, known to its simplicity and precision when compared to other techniques. Linear optical measurements were also made, such as optical absorption and lifetime, to calculate of non-linear optics properties. The results show there is an interaction between the dopants, capable of generating a variation in linear and nonlinear optical parameters under study. / Dissertação (Mestrado)

Dissertação (mestrado)—Universidade de Brasília, Centro de Desenvolvimento Sustentável, Programa de Pós-Graduação em Desenvolvimento Sustentável, 2014. / Submitted by Ana Cristina Barbosa da Silva (annabds@hotmail.com) on 2015-02-06T16:20:32Z No. of bitstreams: 1 2014_GiseleCarneirodeLemosPalmeiraodeAlvarenga.pdf: 3738115 bytes, checksum: 0a5fa360f5c1cb1cff9cbd1da1865105 (MD5) / Approved for entry into archive by Ruthléa Nascimento(ruthleanascimento@bce.unb.br) on 2015-02-13T14:36:08Z (GMT) No. of bitstreams: 1 2014_GiseleCarneirodeLemosPalmeiraodeAlvarenga.pdf: 3738115 bytes, checksum: 0a5fa360f5c1cb1cff9cbd1da1865105 (MD5) / Made available in DSpace on 2015-02-13T14:36:08Z (GMT). No. of bitstreams: 1 2014_GiseleCarneirodeLemosPalmeiraodeAlvarenga.pdf: 3738115 bytes, checksum: 0a5fa360f5c1cb1cff9cbd1da1865105 (MD5) / O objetivo deste estudo foi identificar as redes de pesquisa existentes no Centro de Desenvolvimento Sustentável da Universidade de Brasília - CDS/UnB utilizando os dados registrados no Diretório dos Grupos de Pesquisa – DGP, com vistas a contribuir para melhorar o acesso às informações coletadas e oferecer sugestões que aprimorem o funcionamento do Diretório. A pesquisa evidenciou desconhecimento de uma parte substancial da comunidade científica quanto ao potencial que o Diretório comporta. Isso foi reconhecido pelos próprios respondentes, que sugeriram dentre outras ações, uma maior divulgação sobre os benefícios que este banco de dados pode oferecer, tornando o seu manuseio mais abrangente. Revelou, ainda, a real percepção dos dirigentes de pesquisa sobre o funcionamento do Diretório, o que facilitará sua utilização pela comunidade científica. Também, observou-se que muitas das sugestões propostas já vêm sendo incorporadas, tais como: o registro dos egressos, a inclusão de titulação dos membros do grupo e a possibilidade de inserir instituições parceiras no desenvolvimento da pesquisa. Tais iniciativas bem como a realização desta pesquisa contribuem para tornar o DGP mais conhecido e acessível à sociedade. ________________________________________________________________________________ ABSTRACT / The aim of this study was to identify existing networks of research at the Centre for Sustainable Development at the University of Brasilia - CDS/UnB using the data registered in the Directory of Research Groups – DGP, in order to contribute to improving access to information collected and offer suggestions that will improve the operation of the Directory. The research showed lack of knowledge of a substantial part of the scientific community about the Directory potential’s. This was acknowledged by the respondents themselves, which suggested among other things, greater disclosure about the benefits that this database can provide, making handling more comprehensive. Also brought up the real perception of the managers about the operation of the directory, which will make easier its use by the scientific community. Also, it was observed that many of the proposed suggestions have already been incorporated, such as the registration of graduates, including titration of group members and the possibility of inserting partner institutions in the research. Such initiatives as well as the realization of this research contribute to make the Directory best known and accessible to society.

This thesis is devoted to the investigation of mechanical properties and self-assembly process of materials at the nanoscale. Various nanostructured materials such as nanoparticles, nanotubes, nanowires and thin films are used as constituent elements of nanodevices. Hence, knowledge of the mechanical properties of materials at the nanoscale is extremely important for understanding their functionality in nanodevices. Mechanical properties of nanostructured materials may significantly differ from those of their bulk counterparts due to the high surface to volume ratio in nanostruc-tures. We particularly focus on the role of the surface region on the stiffness of nanomaterials. We have shown that the stiffness of a nanomaterial can be tuned over a wide range by introducing appropriate coating on the nanostructure surface. We have also explored the effects of the surface region on the stability of various phases in a nanostructure. In the second part of this thesis, we have described the self-assembly process of nanostructures mediated by drendrimers. Self-assembly techniques are frequently used to decorate nanostructures into specific networks. The motivation of this study is to investigate the mechanisms which control the effective interaction and the inter-particle distance between nanoparticle-dendrimer compos-ites. Control over the inter-particle separation is very important since it has a strong influence on the electronic and optical properties of the nanostructures. In the following paragraphs, we sum-marize the results of our study. We start with a brief introduction to the mechanical properties and self-assembly process of nanostructures in the first chapter. A brief review of the work done on these topics in the recent past is presented in this chapter. We discuss the results and conclusions of various experimental and numerical studies on these topics. We also mention the motivation for the studies we have carried out. At the end, we briefly describe the numerical methods (molecular dynamics (MD) and density functional theory (DFT)) which have been used in our investigations. In the second chapter, we discuss the effects of the surface region on the mechanical properties of nanostructures. We have investigated the size and growth direction dependence of the mechanical properties of ZnS nanowires and thin films as a case study. We observe that the Young’s modulus of nanowires and thin films strongly depends on their size and growth direction. This size and growth direction dependence of the stiffness of nanostructured materials can be explained in terms of their surface modifications. Since the energy of the surface region is usually higher than that of the core region in a nanostructure, the surface atoms move their positions to minimize the surface energy. As a result, bond lengths at the surface region are usually different from their bulk values. We observe that in ZnS nanowires and thin films, the average bond length at the surface region is lower than that in the core region which remains unchanged from its bulk value. This decrease in the bond length (or equivalently increase in the bond energy) increases the effective stiffness of the entire nanostructure. As the size of the nanowire/thin film increases, the effect of the surface region gradually decreases and hence the Young’s modulus value converges to the bulk value. Since the surface region has a strong influence on the mechanical properties of nanostructures, the stiffness of a nanostructure can be tuned by modifying the surface region with other materials. In chapter three, we have shown that the stiffness of ZnS nanowires can be tuned by introducing a thin CdS shell on top of the ZnS surface. In general, the stiffness of a nanostructure can be increased (decreased) by coating the surface region with a stiffer (less stiff) material. However, the stiffness of the core/shell nanostructures strongly depends on the properties of the interface between the core and the shell. We observe that the binding energy between the core and shell regions is relatively low due to the lattice mismatch at the interface region of core/shell nanostructures. This lower binding energy strongly affects the stiffness of core/shell nanostructures. We have also shown that thermal properties such as thermal conductivity and melting temperature of core/shell structures can be tuned by changing the coating material. In chapter four, we discuss the effects of the surface region on the stability of various phases in a nanostructure. The surface atoms may stabilize a particular phase in a nanostructure which is not a stable phase in the bulk material. In this chapter, we investigate the stability of the h-MgO phase, an intermediate structure found during the wurtzite to rock salt transformation, in CdSe nanostructures. We observe that this five-fold coordinated phase is more stable at lower temperatures and smaller sizes of the nanowires. The appearance of this phase has not been observed till now in experiments. We show that this phase is not stable for larger CdSe nanocrystals on which the experiments have been done. In the rest of the thesis, we have presented the results of our studies of self-assembly of nanostructures mediated by DNAs and dendrimers. First we describe in chapter five the nature of the effective interaction between two PAMAM dendrimers. Dendrimers are frequently used to coat surfaces of nanoparticles to prevent the nanoparticles from aggregation. The interaction between such nanoparticle-dendrimer composites depends strongly on the nature of the effective interac-tion between dendrimers. We have used fully atomistic MD simulations to calculate the potential of mean force (PMF) between two PAMAM dendrimers. We show that the effective interaction strongly depends on the size (generation) and protonation level of the dendrimers. The PMF profiles of nonprotonated dendrimers show a global minimum which represents the attractive nature of the interaction between the dendrimers up to a certain center-to-center distance. On the other hand, the interaction between protonated dendrimers is repulsive throughout their interaction re-gion. The PMF profiles are fitted very well by a sum of an exponential and a Gaussian function. This observation is in contradiction with some of the results of existing coarse-grained simulations which predicted the effective interaction between dendrimers to be Gaussian. Our atomistic simulation which includes all the local fluctuations is expected to give more accurate results. Information about the effective interaction between two dendrimers helps in understanding how dendrimer molecules can be used to control the interaction strength and the preferred inter-particle distance between two nanostructures. In chapter six, we discuss the effective interaction between two dendrimer grafted gold nanoparticles. We observe that dendrimer molecules can get adsorbed spontaneously on the surface of a gold nanoparticle. These grafted dendrimers significantly alter the interaction between the gold nanoparticles. We have explored the effects of proto-nation level and the density of the grafted dendrimers on the effective interaction between two gold nanoparticle-dendrimer composites. We observe that these nanoparticle-dendrimer composites at-tract each other at low grafting density. However, the interaction strength and the inter-particle distance at the minimum of the potential are much lower and higher, respectively than those between two bare gold nanoparticles. Interestingly at higher grafting density, the nature of the interaction between the nanocomposites depends on the protonation level of the grafted dendrimers. Nanoparticles grafted with nonprotonated dendrimers still attract each other but with lower inter-action strength and higher inter-particle distance compared to the values for low grafting density. On the other hand, nanocomposites grafted with protonated dendrimers repel each other at high grafting density. Thus we show that the effective interaction and the optimal inter-particle distance between the nanostructures can be tuned over a wide range by using a suitable grafting density and protonation level of the dendrimers. In the seventh chapter, we describe a strategy to assemble dendrimers with the help of sin-gle stranded DNA (ssDNA). We attach an ssDNA to one dendrimer and a complementary ssDNA to a second dendrimer. These two complementary ssDNAs bind with each other through base pair formation to assemble the dendrimers into a single structure. The complementary ssDNAs form a dsDNA which is rigid enough to maintain the inter-dendrimer distance almost the same as the length of the DNA. The inter-dendrimer distance can be tuned by changing the DNA length. However, this method strongly depends on the protonation level of the dendrimers. It works well only for nonprotonated dendrimers. Since the protonated dendrimers are positively charged, they strongly interact with the negatively charged ssDNAs through electrostatic interaction. As a result, ssDNAs wrap the dendrimer surface and hence the inter-dendrimer distance can not be controlled. We have also verified that this method works for multiple nonprotonated dendrimers as well. In the final chapter of this thesis, we summarize the main results and conclude with a brief discussion of future directions of research on the problems considered in the thesis.

L'objectif principal de ma thèse est d'évaluer la réaction du marché à la publication de différentes annonces de notation de crédit. Précisément, la thèse étudie l'impact des annonces sur la volatilité des prix et sur plusieurs indicateurs d'activité et de liquidité sur le marché obligataire et de CDS. Un chapitre examine également si et comment le prix des actions réagit aux retraits de notation de crédit. / The main aim of my thesis is to evaluate the market reaction to credit rating announcements. Precisely, the thesis studies the impact of the release of such announcements on the price volatility, liquidity and several trading activity measures in the bond market and CDS. A chapter also examines whether and how the issuer stock price reacts to the withdrawal of its credit rating.

This dissertation reports on an exploratory study investigating the potential of recorded audio media (i.e. audiocassettes/CDs) as a method of health communication in South Africa. The investigation examines recorded audio media as an alternative to printed brochures. People need access to information in order to make informed decisions about their health. In South Africa, the high HIV/AIDS infection rate is a case in point. The literature review deals with the accessibility of information in terms of physical accessibility (whether the receiver can find, operate and use the communication medium); and semantic accessibility (whether the receiver understands the message disseminated via the medium). Through the review, it was discovered that, where necessary, information must then be repackaged from an inaccessible to an accessible and appropriate format. Factors like visual disabilities, low levels of literacy and low reading proficiency, can render printed information inaccessible. This study discusses and researches the feasibility of recorded audio media (audiocassettes/CDs) as an alternative to print-based brochures by means of a comparative literature review and empirical study. Selected HIV/AIDS brochures (developed by the Department of Health) and similar recorded audio messages were evaluated amongst the target audience in order to compare the comprehension of the messages, the accessibility and acceptability of both media forms. The study was conducted at four public health clinics, where individual structured interviews and focus group interviews were employed as data collection methods. The data was analysed by means of qualitative content analysis. The findings indicate the definite potential of the use of recorded audio media in health and HIV/AIDS communication, and should be explored further. The comprehension of the audio messages was better than that of the printed brochures indicating the semantic accessibility of the audio messages. The positive reaction of the research participants toward the recorded audio messages also indicates the acceptability of the medium. Incorporating audiocassettes into the media mix of HIV/AIDS and other development and/or health communication campaigns, will contribute to the overall effectiveness of the communication strategy. / Dissertation (MA (Development Communication))--University of Pretoria, 2008. / Information Science / unrestricted

This dissertation reports on an exploratory study investigating the potential of recorded audio media (i.e. audiocassettes/CDs) as a method of health communication in South Africa. The investigation examines recorded audio media as an alternative to printed brochures. People need access to information in order to make informed decisions about their health. In South Africa, the high HIV/AIDS infection rate is a case in point. The literature review deals with the accessibility of information in terms of physical accessibility (whether the receiver can find, operate and use the communication medium); and semantic accessibility (whether the receiver understands the message disseminated via the medium). Through the review, it was discovered that, where necessary, information must then be repackaged from an inaccessible to an accessible and appropriate format. Factors like visual disabilities, low levels of literacy and low reading proficiency, can render printed information inaccessible. This study discusses and researches the feasibility of recorded audio media (audiocassettes/CDs) as an alternative to print-based brochures by means of a comparative literature review and empirical study. Selected HIV/AIDS brochures (developed by the Department of Health) and similar recorded audio messages were evaluated amongst the target audience in order to compare the comprehension of the messages, the accessibility and acceptability of both media forms. The study was conducted at four public health clinics, where individual structured interviews and focus group interviews were employed as data collection methods. The data was analysed by means of qualitative content analysis. The findings indicate the definite potential of the use of recorded audio media in health and HIV/AIDS communication, and should be explored further. The comprehension of the audio messages was better than that of the printed brochures indicating the semantic accessibility of the audio messages. The positive reaction of the research participants toward the recorded audio messages also indicates the acceptability of the medium. Incorporating audiocassettes into the media mix of HIV/AIDS and other development and/or health communication campaigns, will contribute to the overall effectiveness of the communication strategy. / Dissertation (MA (Development Communication))--University of Pretoria, 2007. / Information Science / MA / unrestricted

Denna studie undersöker språket i informationstexter om efterförlossningsvård ur ett kritiskt diskursanalytiskt perspektiv. Syftet med denna studie har varit att synliggöra normer och diskurser om efterförlossningsvård om vad som räknas som sjukt och inte, vad som är vårdens respektive individens ansvar och vilka skador som lyfts fram eller göms undan. Uppsatsen utgår ifrån teorier om systemisk-funktionell grammatik (SFG) och kritiska diskursstudier med fokus på makt och kön. De metoder som används är transitivitet och modalitet från SFG samt en studie av tilltal. Undersökningen visar att infinitivfraser och passiv används för att flytta bort fokus från ämnen som toabesök, sex och vissa typer av skador. Andra strategier som används är att använda pronomenet en del när känsligare ämnen behandlas. Imperativ och förpliktelsemodaliteter av låg grad används för att uppmana till självvård. Studien visar att texterna skapar en normalitet där vissa skador beskrivs som ‘normala’ på ett sätt som inte kräver sjukvård, medan andra beskrivs som ‘onormala’ och som kräver sjukvård. Samma skada kan också skrivas fram som ‘normal’ i vissa situationer och ‘onormal’ i andra. Texterna reproducerar också normer kring kön, sexualitet och relationer och vilka handlingar och attribut som är kopplade till dessa.