Made available in DSpace on 2014-06-12T15:51:31Z (GMT). No. of bitstreams: 2 arquivo5719_1.pdf: 2389208 bytes, checksum: fd3ee770e606c50de4354c931bb7ce22 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Nanocristais fluorescentes de semicondutores, quantum dots (QDs) vêm sendo obtidos para diversas aplicações por vários grupos de pesquisa em todo o mundo. A maioria das rotas sintéticas encontradas na literatura refere-se à produção desta classe de nanomateriais em meio orgânico e condições de alta temperatura. A síntese em meio aquoso consiste em uma metodologia simples para a obtenção de nanocristais com estrutura core-shell de CdSe/CdS altamente fluorescentes em regime de confinamento quântico. Estes QDs dispersos em água foram sintetizados através da adição de sal de cádmio, selênio reduzido e ácidos orgânicos com radicais tióis. Tais compostos orgânicos nesse caso são fundamentais para a estabilização das partículas coloidais, além de fornecerem íons sulfeto, que participam da formação da camada de passivação. A caracterização dos QDs obtidos foi realizada através de medidas espectroscópicas e análises estruturais. Foram feitos também planejamentos quimiométricos e avaliações temporais da luminescência para se saber quais os melhores parâmetros e quando os QDs apresentam a melhor intensidade de luminescência após serem sintetizados. Devido sua elevada luminescência, estabilidade em meio aquoso e baixa fotodegradação, os QDs de CdSe/CdS foram utilizados para a marcação de fluorescência de cromossomos metafásicos. Apesar do grande interesse e crescente aumento na produção de QDs, os mesmos apresentam muitas vezes, metais de elevada toxicidade, tais como o Cádmio. Assim, o tratamento dos resíduos oriundos da produção de quantum dots, que ainda é alvo de poucos trabalhos, é aqui abordado mais especificamente com relação ao tratamento através de processos oxidativos avançados, de rejeitos oriundos da síntese dos QDs de CdSe/CdS, objetos do presente trabalho

This thesis investigate the structure of cadmium sulfide (CdS) nanoparticles and its stabilization by a surfactant - cetyltrimethylamonnium cation CTA+ and further describe interactions among stabilized CdS nanoparticles and the surface of the layered clay mineral - montmorillonite with using the molecular simulation methods. Initial models of the CdS nanoparticles were build for both crystal structures (Greenockit (G) and Hawleyit (H)). The preferred orientations of the molecules of CTA+ for both crystal types of CdS nanoparticles were found with respect to minimum energy. Prefered orientation is monolayer for Greenockite and bilayer for Hawleyite. Models with the preferred orientation of the molecules of CTA+ were placed on the surface of montmorillonite and after optimization, adsorption energy of CdS nanoparticles with its envelope and montmorillonite surface was calculated. All results and used procedures were compiled in the form of practice for the subject Computational experiments in the theory of molecules I - NBCM100 taught at MFF UK in Prague.

This thesis consists of one hedge fund study and two credit default swap (CDS) studies. The first study investigates the relationship between mega hedge funds (the largest 25% of funds) and two bond yields (U.S. Treasury yield and Baa yield). Using a merged sample of 9,725 hedge funds from 1994 to 2012, I find that hedge fund outflow produced a more significant relationship than inflow, and the dollar outflow of large hedge funds can predict the increase in the bond yields. The association is also more pronounced for large funds with a short notice period prior to redemption. The results suggest that hedge fund flows provide predictive information for the movement of bond yields. The second study investigates the systematic and firm-specific credit and liquidity risks of CDS spreads. Using data on CDS spreads of 356 U.S. firms from 2002 to 2011, I find that systematic credit and liquidity risks are important in cross-sectional prediction of CDS spreads. In addition, the importance of systematic liquidity risk becomes substantial since the financial crisis in 2007. This finding challenges the current Basel III procedures for counterparty credit risk regulations, in which only pure default should be used. In addition, the systematic credit and liquidity factors can be used as a proxy for CDS spreads of firms that do not have traded CDSs. The last study extends Carr and Wu (2010), in which deep out-of-the-money (DOOM) put options and CDSs are associated as they both provide credit insurance for credit protection buyers. Using the Nelson-Siegel (1987) model, I obtain the credit and illiquidity components for DOOMs and CDSs over the period from May 2002 to May 2012. I show that, after controlling the factors that explain the difference between the DOOM and CDS markets, the components converge over time in these two markets. Thus, I can exploit the observed convergence pattern by constructing a simple trading strategy, and this benchmark strategy produces a positive return. I further construct two other strategies based on the component information, and these two refined strategies outperform the benchmark strategy by the Sharpe ratio and Carhart alpha. My three studies contribute to the literature in hedge fund systemic risk and CDS credit and liquidity risks.

Les verres dopés par des ions de terres rares ou/et des nanoparticules de semi-conducteurs continue à faire l’objet de plusieurs recherches grâce à leur efficacité dans les domaines d’optoélectroniques. En effet, ces matériaux sont parmi les candidats potentiels pour des applications en photonique tels que les amplificateurs à fibre optique, les convertisseurs de lumière, les capteurs et les guides d'ondes 3D.Dans le cadre de cette thèse, des verres à base de silice (SiO2)dopé par des ions d’europium (Eu3+) ont été préparés par le processus sol-gel. Afin de mieux disperser les ions de terres rares et d’améliorer leur émission, les verres ont été codopés par le phosphore et/ou l’aluminium. Des nanoparticules de semi-conducteur (CdS) ont été aussi introduite dans le verre afin d’augmenter l’absorbance de la lumière excitatrice et d’obtenir une émission plus intense des ions Eu3+. Les verres préparés ont été analysés par photoluminescence et par la technique de rétrécissement des raies de luminescence (FLN). Ces mesures ont été suivi par des simulations par la méthode de dynamique moléculaire (DM)afin d’étudier l’effet de phosphore et/ou de l’aluminium sur l’environnement local des ions d’europium et la dispersion de ces ions dans la matrice vitreuse. La présence de deux types de sites des ions d’europium dans le verre de silicophosphates a été mise en évidence et a été confirmé par les deux techniques (FLN et DM). L’effet des nanoparticules de CdS sur l'émission des ions Eu3+dans un verre de silicophosphate a été aussi étudié et il a été montré que l’émission des ions Eu3+ est considérablement dépendante de la concentration des nanoparticules de CdS et de la température de recuit. / Glasses doped with rare earth ions and/or semiconductor nanoparticles continues to be the subject of several studies due to their effectiveness in optoelectronic fields. Indeed, these materials are among the potential candidates for photonic applications such as optical fiber amplifiers, light converters, sensors and 3D waveguides. As part of this thesis, silica-based glasses (SiO2) doped with europium ions (Eu3+) were prepared by the sol-gel process. In order to better disperse the rare earth ions and improve their emission, the glasses were codoped with phosphorus and/or aluminum. Semiconductor nanoparticles (CdS) were also introduced into the glass in order to increase the absorbance of the excitation light and to obtain a more intense emission of Eu3+ ions. The prepared glasses were analyzed by photoluminescence and by the technique of Fluorescence line narrowing (FLN). These experimental measurements were followed by theoretical simulations using the molecular dynamics method (DM) to study the effect of phosphorus and/or aluminum on the local environment of the europium ions and their dispersion in the vitreous matrix. The presence of two types of europium ion sites in the glass silicophosphates has been demonstrated and confirmed by two techniques (FLN and DM). The effect of CdS nanoparticles on the emission of Eu3+ ions in a glass silicophosphate was also studied and it was shown that the emission of Eu3+ ions is considerably dependent on theconcentration of CdS nanoparticles and annealing temperature.

This thesis comprises of three essays. The first essay is titled 'Do Acquiring Firms Manage Earnings?' and is co-authored with Professor Anand M. Vijh. The second essay is titled 'Do Firms Have a Target Leverage? Evidence from Credit Markets' and is joint work with Professors Anand M. Vijh and Redouane Elkamhi. The third is essay is single authored and titled 'Bondholder Wealth Effects of Fraudulent Reporting.' In the first essay, we investigate possible earnings management by inflating discretionary accruals in a sample of 1,719 cash acquirers and 895 stock acquirers during 1989-2005. Following previous literature, we document higher ROA-matched discretionary accruals for stock acquirers than for cash acquirers. However, simulation evidence with quarterly data shows that ROA-matched discretionary accruals are misspecified for both high-growth and low-growth firms. This is relevant to the current investigation because the median sales growth rate equals 12.1% for cash acquirers and 38.5% for stock acquirers (besides similar differences in other growth measures). We propose a new discretionary accrual measure that controls for both ROA and sales growth. This measure is well-specified and powerful in detecting earnings management in stratified random samples, and it leads to an insignificant difference between discretionary accruals of cash and stock acquirers. Other tests of acquirer incentives to manage earnings, market reaction to earnings management, and time delay between earnings announcement and merger announcement strengthen the evidence against earnings management attributed to stock acquisitions. In the second essay, we propose credit market based test of whether firms have a target leverage. The static tradeoff theory of capital structure hypothesizes that firms have a target leverage which optimizes firm value in the presence of benefits and costs of leverage (such as taxes and bankruptcy costs). If firms adjust their actual leverage toward this target leverage over time, then rational investors should consider both current and target leverage in pricing contracts whose value depends on the firm's default risk. Using a large sample of corporate bonds and credit default swap (CDS) contracts during 2000 to 2007, we document evidence consistent with this prediction. In particular, target leverage is both an economically and statistically significant determinant of bond and CDS spreads, and its role increases with contract maturity. Credit ratings also reflect the effect of target leverage, which suggests that the credit rating agencies rate firms as if their capital structure decisions are consistent with the tradeoff theory. In the third and final essay, I examine how the disclosure of fraudulent reporting affects bondholder wealth, credit ratings, and contract features of new bond issues. I find that fraud announcements trigger swift, sharp, and long lasting credit rating downgrades and are associated with significant declines in bondholder wealth. An examination of new bond issues confirms a significant increase in both the yield spread and the gross spread charged by the investment bank compared to pre-fraud levels. Moreover, a significant proportion of bonds issued after a fraud contain call provisions that are more expensive in the short run but may be potentially value maximizing in the long run if credit conditions improve. Thus, I argue that managers are optimistic that the increase in the cost of debt induced by the fraud is temporary. However, contrary to managers' optimistic beliefs, I find that corporate credit ratings, once decreased, remain significantly depressed for at least three years following the fraud announcement.

The aim of this thesis is to draw up a detailed analysis of a business plan to build retail brand store with Apple products. The analytical part of this thesis is devoted to the selected market and to the conditions to build official Apple store. Processed business plan is based on real data, questionnaire and expert´s experiences in the field and try to determine the success of the business as precisely as possible. The financial plan includes necessary expenses and planned profits which shows in two versions what conditions must be done to achieve a profit.

Hlavním cílem této práce je vyvinout aplikaci sloužící pro reportování správy rizik za použití nejnovějších technologií, které nabízí firma SAP. V první části je nastíněn koncept problematiky správy rizik, jsou vysvětleny klíčové pojmy a zmíněny některé problémy z této oblasti, se kterými se společnosti v dnešní době potýkají. Dále jsou vyjmenována a srovnána některá z komplexních softwarových řešení, které jsou momentálně dostupné na trhu. Práce pokračuje popisem technologií, které jsou využity při tvorbě výsledné aplikace. Proces vývoje zahrnoval analýzu stávajícího datového modelu, tvorbu nové datové struktury a její validaci a návrh samotného uživatelského prostředí pro zobrazování těchto dat. Výsledná aplikace umožňuje získávat správná data z databáze a zobrazovat je odpovídajícím způsobem.

Cette thèse de doctorat s’articule en trois chapitres. Le premier chapitre s’attache à trouver les déterminants principaux des variations hebdomadaires des marges de CDS, en période normale. Le deuxième chapitre se concentre, quant à lui, sur le comportement des marges de CDS dans les situations extrêmes. Nous exploitons dans ce chapitre les outils couramment employés dans l’analyse du risque systémique (CoVaR et régression quantile). Le troisième et dernier chapitre s’intéresse à l'impact des modifications de notations émises par les agences de rating (sur les marges de CDS). Nous procédons ici à une étude d’événements. Ces trois chapitres, de nature empirique, analysent donc, sous des angles différents. Ils insistent aussi dans leur interprétation sur la dimension sectorielle du marché des CDS. Bien que conçus séparément et indépendamment; les résultats de ces chapitres apparaissent, pour l’essentiel, assez cohérents. Ainsi, dans le premier chapitre, une série d’analyses en composantes principales menées sur les marges de CDS indiquent que le « secteur » constitue un facteur important. Dans le deuxième chapitre, les résultats fournis par la mesure de risque systémique appelée CoVaR suggèrent aussi que les secteurs dirigent le comportement des CDS individuels dans les moments extrêmes. / This thesis examines in three empirical essays levels and changes of CDS spread related to largest European companies. In the first chapter, we aim at identifying most important variables that drive CDS spreads in normal market conditions We suggest a list of new microeconomic variables and we find there exist some remaining sector wide common factors. In chapter two, we examine credit risk spillovers of CDS and equity markets under extreme conditions. To this end, we implement among other the very recent CoVaR technology of related entities. We also find here indirect evidences that sectors govern the behavior of individual CDS. In chapter three, we finally undertake a number of event studies on CDS and Equity daily data making use of hand-collected credit rating changes. Among other things, we evidence that both CDS spreads and equity prices move as the rating changes but also that movements differ according to upgrades, downgrades, succession and turnovers.

Kreditderivat är ett finansiellt instrument som upplevt en explosiv utveckling på stora finansiella marknader som exempelvis de i USA och England. Dock har denna massiva utveckling, relativt sett, uteblivit på den svenska finansmarknaden. Denna kandidatuppsats syftar till att undersöka vilka faktorer som påverkar användandet av kreditderivat i Sverige. Både positiva och negativa faktorer avhandlas på ett objektivt sätt med relevanta källor av olika slag. Fokus ligger på grundformen av kreditderivat, Credit Default Swaps. Genom grundläggande forskningsarbete avgränsar vi uppsatsen till sex stycken faktorer som vi tror kommer att påverka kreditderivats utveckling i Sverige. Dessa är: EMU-inträde, Värdepapperisering, Central Clearing Counterparty (CCP), Säkerställda Obligationer, Basel III och Företagsobligationer. Vi analyserar dessa faktorer och drar slutsatser hur och om varje faktor kommer påverka användandet av kreditderivat i Sverige. Angående effekten av ett eventuellt EMU-inträde för Sveriges del anser vi redan vara överspelad på grund av att större svenska aktörer redan handlar till stor del i valutan Euro. Vidare har värdepapperisering varit en tillväxtfaktor historiskt, bl.a. i USA, men i spåren av den finansiella krisen kommer inte värdepapperis ering få samma tillväxteffekt på kreditderivat som den tidigare haft. En annan potentiell tillväxtfaktor kan vara användandet av en CCP men den spelar förmodligen roll i ett senare skede i den svenska marknadens utveckling. Vidare så kräver säkerställda obligationer mer forskning, vår utredning pekar på ett antal scenarion där de kan påverka utvecklingen antingen positivt eller negativt. Slutsatsen är att Sverige är redo för kreditderivat och att de två viktigaste tillväxtfaktorerna är: Ett ökat användande av företagsobligationer i kombination med införandet av Basel III lagstiftningen för finansiella institut. Vi tror med hänsyn till de två sistnämnda faktorerna, och till viss del CCP-faktorn, att användandet av kreditderivat kommer att öka i Sverige i framtiden.

京都大学 / 0048 / 新制・課程博士 / 博士(経済学) / 甲第21530号 / 経博第598号 / 新制||経||289(附属図書館) / 京都大学大学院経済学研究科経済学専攻 / (主査)教授 江上 雅彦, 教授 西山 慶彦, 准教授 砂川 伸幸 / 学位規則第4条第1項該当 / Doctor of Economics / Kyoto University / DGAM