Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 103-109). Also available in electronic version.

Thesis (M.S.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (p. 94-95)

Thesis (M.S.)--Ohio University, August, 2004. / Title from PDF t.p. Includes bibliographical references (p. 81-83)

In the area of interest the occurence of selected alien plants have been mapped. Their approximate abundance have been determined, as well as the locality, which is occuppied by certain species and the enviroment in which alien species occurs. The centres, out of which the species spread out have been determined or estimated, as well as have been estimated tendencies for their possible future expansive. The changes in the occurence in stated vegetation periods have also been introduced and the fact whether the species seems to be expansive or stationary. Localities of the occurence of alien plants have been drawn into maps, which are parts of the supplement.

Made available in DSpace on 2014-06-12T15:08:10Z (GMT). No. of bitstreams: 2 arquivo255_1.pdf: 546370 bytes, checksum: 36238f887c1243b1677559bcdbc93462 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / Fundação de Amparo a Pesquisa do Estado de Alagoas / Em um mercado competitivo, algumas empresas procuram se diferenciar como empresas com boa governança , e assim, tornam-se mais atraentes para aos investidores, aumentando a quantidade de investidores interessados em alocar recursos em seus projetos. Outro aspecto relevante para os investidores são os ratings de crédito, que auxiliam no processo de compra ou venda de títulos destas empresas. O objetivo principal deste estudo é verificar se a qualidade das práticas de governança corporativa das empresas listadas na Bovespa tem alguma relação com a qualidade dos ratings e o spread das debêntures emitidas pelas empresas, entre 2005 e 2007. Os dados foram coletados no site da Comissão de Valores Mobiliários e do Sistema Nacional de Debêntures e tratados com a utilização do método Probit Ordenado e Mínimos Quadrados Ordinários. Os resultados mostraram que as práticas de governança (medido pelo IGC) influenciam negativamente a qualidade de crédito, em relação à variável concentração de propriedade (CP) quando em substituição ao IGC apresentou sinal positivo, resultado que corrobora com outros estudos semelhantes. Com relação ao spread obteve-se resultados não conclusivos, pois o índice de governança não apresentou sinal constante em conjunto com a variável de desempenho ROA. No entanto, ao substituir o índice de governança pela variável de concentração de propriedade foi encontrada uma relação negativa com o spread, sinalizando que os spreads pagos pelas empresas tendem a ser menores com a alta concentração de propriedade

Cette thèse sur travaux empiriques en quatre articles s’intéresse aux déterminants de risque de défaut souverain. Le premier chapitre résume l’état de l’art du risque de défaut souverain et trois principales approches des déterminants du risque de défaut souverain: le modèle structurel, le modèle dynamique stochastique et les modèles économétriques. Le deuxième chapitre étudie la probabilité de défaut de l’Argentine (2002) en utilisant un modèle structurel proposé par Gray and Malone 2008. Le troisième chapitre propose un modèle stochastique afin de calculer le spread du crédit souverain journalier. Les deux derniers chapitres économétriques déterminent deux proxies du risque de défaut souverain: Sovereign CDS spread et Emerging Market Bond Index Plus (EMBI+). Le quatrième chapitre essaye de déterminer le sovereign CDS spread à longterme et court-terme en utilisant trois estimations: Pooled Mean Group, Mean Group et Dynamic Fixed Effect. Dans le dernier chapitre, on applique un modèle non-linéaire asymétrique Autorégressif à retards échelonnés pour étudier l’effet d’asymétrie à longterme de compte courant sur l’EMBI+ y compris les variables explicatives telles que la dette extérieure et les réserves internationales pour deux pays émergents: la Turquie et le Brésil. / This thesis on empirical results in four articles focused on the determinants of the sovereign default risk. The first chapter summarizes the state of the art of sovereign default risk and the three main approaches of determinants of sovereign default risk: the structure model, the dynamic stochastic model and the econometric models. The second chapter studies the default probability in Argentina (2002) by using a structural model proposed by Gray and Malone 2008. The third chapter provides a stochastic model to calculate the daily sovereign credit spread. Last two econometric chapters determine two sovereign default risk proxies: Sovereign CDS spread and Emerging Market Bond Index Plus. The fourth chapter focuses on the sovereign CDS spread in long-run and short-run by using three estimations of Pooled Mean Group, Mean Group and Dynamic Fixed Effect. The last chapter applies a nonliear Autoregressive Distributed Lag asymmetry model to study the long-run asymmetric effect of the current account to the EMBI+ including the explanatory variables such as the external debt and international reserves for the two typical emerging countries Turkey and Brazil.

Titanium dioxide (TiO2) is an essential component in a white paint formulation due to its excellent light scattering ability. TiO2 also happens to make up most of the raw materials cost. Viable replacements to TiO2 do not currently exist in a feasible manner. Rising costs in the recent TiO2 supply shortage have forced coatings formulators to find a balance between cost and performance. One method includes partial substitution of TiO2 with cheaper material such as calcium carbonate (CaCO3), which serves to occupy volume. The purpose of this study was to compare the coating spread rate of paints with varying TiO2 and CaCO3 pigment volume concentration (PVC). Different sized CaCO3 particles were used in this study. A series of PVC ladder studies were performed at keeping CaCO3 PVC constant. Paints were formulated at the same volume solids to minimize variability. Weighed coating draw-downs were prepared to measure the contrast ratio. The coating spread rates were obtained with the DuPont Spread Rate program, which relies on Kubelka-Munk relationships, which takes into account the physical properties of the paint. These spread rate values were compared to one another across type and size to find common trends. Critical pigment volume concentration (CPVC) values were determined through regression of the spread rate values and compared to oil absorption tests. It was found that replacement of up to 20 PVC of TiO2 with CaCO3 could marginally increase the spread rate, thus increasing the efficiency of TiO2. The spread rate increased modestly as similarly sized extender particles were initially introduced, then dropped at higher extender levels. Data analysis revealed that CPVC was influenced based on the size and amount of the extender particle present, which can be used to predict resin demand of a paint system.

TESIS PARA OPTAR AL GRADO DE MAGISTER EN FINANZAS / Un fenómeno se viene observando en el mercado de los bonos corporativos chilenos. Las tasas de interés en el mercado local están actualmente muy bajas, lo que sería una buena oportunidad para financiar proyectos de inversión a través de emisión de deuda por parte de las empresas. Sin embargo, dichas inversiones se encuentran actualmente frenadas, dado que las empresas tienen pocos proyectos de inversión en sus carpetas, por lo que no quieren endeudarse emitiendo bonos para financiarse y prefiriendo hacerlo para refinanciar deuda, ya que así aprovechan la coyuntura de tasas largas bajas a través de estas estrategias, es decir, gracias a lo recaudado las emisiones prepagan las deudas de corto plazo, toman una deuda más larga – a veces a tasas más bajas,- y quedan con un flujo de pasivo más ordenado, es por eso que el uso de estos recursos no se están viendo en nuevos proyectos, el otro camino que están tomando las emisiones de bonos chilenos es destinado a explorar nuevas oportunidades fuera de Chile demostrando la madurez del mercado. En la otra vereda del mercado de los bonos, se encuentran los demandante de estos instrumentos como son las Administradoras de Fondos de Pensiones (AFP’s) y las compañías de seguros de vidas, quienes tienen apetito en invertir y necesitan instrumentos para invertir, calzar pasivos, o bien obtener retornos de largo plazo adecuados para la naturaleza de su negocio. Al observar el mercado definidos por activos bajo inversión (AUMs) utilizando como proxys del crecimiento de AFP’s y Cías de Seguros, vemos que presentan un incremento del 5% entre 2014-2015 y del 3% para período 2015-Sept.2016 y en el caso del mercado de los seguros, las tasas de crecimiento son del 12% para período 2014- 2015 y del 6% para período 2015- junio 2016 respectivamente, por lo que se incrementa la necesidad de colocar bonos en un escenario de escasas emisiones.

This study set out to examine the effectiveness and reliability of six modifications to the Zhang et al. (2004) CPT-based lateral spread model. A regression analysis, distribution charts, and a discriminant analysis are performed to determine how effective the modifications are on the model. From the comparisons and statistical analysis performed in this study, application of these modifications reduces over-predictions from strain-based prediction methods. Unfortunately, the tendency to under-predict displacements on average is also increased.

Sodium (23Na) plays a critical role in all organisms – it is crucial in cellular homeostasis, pH regulation and action potential propagation in muscle and neuronal fibres. Healthy cells have a low intracellular 23Na and high extracellular concentration, with the sodium-potassium pump maintaining this sodium gradient. In the human brain approximately 50% of its total energy consumption is occupied by maintenance of this gradient, demonstrating the pump’s importance in health. A failure of the sodium-potassium pump leads to cellular apoptosis and ultimately necrosis, with potentially disastrous results for neurological function. Magnetic resonance imaging (MRI) of 23Na is of great interest because of the ubiquity of sodium in cellular processes. However, it is hampered by many technical challenges. Among these are a low gyromagnetic ratio, short T2∗ relaxation times, and low concentrations all of which lead to long acquisitions in order to account for the poor inherent signal. In addition, 23Na MRI requires specialized hardware, non-standard pulse sequences and reconstruction methods in order to create images. These have all contributed to render clinical applications for 23Na MRI virtually non-existent, despite research indicating sodium’s role in various neurological disorders, including multiple sclerosis, Alzheimer’s, stroke, cancer, and traumatic brain injury. This work is motivated by a desire to use 23Na MRI in clinical settings. To that end, hardware and software methods were initially developed to process sodium images. In order to quantify the imaging system the point-spread function (PSF) and the related modulation transfer function (MTF) were calculated with the aid of a 3D-printed resolution phantom with different 23Na concentrations in gelatin. Two pulse sequences, density-adapted projection reconstruction (DA-3DPR) and Fermat looped orthogonally encoded trajectories (FLORET), with similar acquisition times were tested. Reconstructions were performed with the non-uniform fast Fourier transform. Results indicated a full-width, half-maximum (FWHM) value of 1.8 for DA-3DPR and 2.3 for FLORET. In a follow-up study, simulation experiments were added to various sodium phantom concentrations in 3% agar. The simulations indicated high potential variability in the MTF calculations depending on the methodology, while the phantom experiments found a FWHMs of 2.0 (DA-3DPR), and 2.5 (FLORET). Diffusion tensor imaging (DTI) is an MRI technique with wide adoption for the assessment of a variety of neurological disorders. Combining DTI with 23Na MRI could provide novel insight into brain pathology; however, a study with a healthy population is warranted before examinations with other populations. Fifteen subjects were scanned with DTI and sodium MRI, and the latter was used to derive voxel-wise tissue sodium concentration (TSC). Regional grey and white matter (WM) TSC was analyzed and compared to fractional anisotropy (FA) and cerebrospinal fluid (CSF) proximity. Results indicated that WM voxels proximal to CSF regions (i.e. corpus callosum) could have lower than expected FA values and higher measured TSC, with an inverse correlation between TSC and distance to CSF. This is likely the result of the broad PSF of 23Na MRI, as regions distal to CSF did not exhibit this phenomenon. This potentially represents a confounding effect when interpreting sodium concentrations, especially in regions proximal to the high 23Na content in CSF. / Thesis / Doctor of Philosophy (PhD)