Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent Ca²⁺ mobilising messenger in mammalian and non-mammalian cells. Studies on a variety of cell types suggest that NAADP evokes Ca²⁺ release from a lysosome-related store and via activation of a receptor distinct from either ryanodine receptors (RyR) or inositol 1,4,5-trisphosphate (IP₃) receptors (IP₃R). However, the identity of the NAADP receptor has, until now, remained elusive. In this thesis I have shown that NAADP-evoked Ca²⁺ release from lysosomes is underpinned by two-pore channels (TPCs), of which there are 3 subtypes, TPC1, TPC2 and TPC3. When stably over-expressed in HEK293 cells, TPC2 was found to be specifically targeted to lysosomes, while TPC1 and TPC3 were targeted to endosomes. Initial Ca²⁺ signals via TPC2, but not those via TPC1, were amplified into global Ca²⁺ waves by Ca²⁺-induced Ca²⁺ release (CICR) from the endoplasmic reticulum (ER) via IP₃Rs. I have shown that, consistent with a role for TPCs in NAADP-mediated Ca²⁺ release, TPC2 is expressed in pulmonary arterial smooth muscle cells (PASMCs), is likely targeted to lysosomal membranes, and that TPCs also underpin NAADP-evoked Ca²⁺ signalling in this cell type. However, and in contrast to HEK293 cells, in PASMCs NAADP evokes spatially restricted Ca²⁺ bursts that are amplified into global Ca²⁺ waves by CICR from the sarcoplasmic reticulum (SR) via a subpopulation of RyRs, but not via IP₃Rs. I have demonstrated that lysosomes preferentially co-localise with RyR subtype 3 (RyR3) in the perinuclear region of PASMCs to comprise a “trigger zone” for Ca²⁺ signalling by NAADP, away from which a propagating Ca²⁺ wave may be carried by subsequent recruitment of RyR2. The identification of TPCs as a family of NAADP receptors may further our understanding of the mechanisms that confer the versatility of Ca²⁺ signalling which is required to regulate such diverse cellular functions as gene expression, fertilization, cell growth, and ultimately cell death.

This thesis presents several problems based on papers written jointly by the author and Dr. Christian-Oliver Ewald. Firstly, the author extends the model presented by Fershtman and Nitzan (1991), which studies a deterministic differential public good game. Two types of volatility are considered. In the first case the volatility of the diffusion term is dependent on the current level of public good, while in the second case the volatility is dependent on the current rate of public good provision by the agents. The result in the latter case is qualitatively different from the first one. These results are discussed in detail, along with numerical examples. Secondly, two existing lines of research in game theoretic studies of fisheries are combined and extended. The first line of research is the inclusion of the aspect of predation and the consideration of multi-species fisheries within classical game theoretic fishery models. The second line of research includes continuous time and uncertainty. This thesis considers a two species fishery game and compares the results of this with several cases. Thirdly, a model of a fishery is developed in which the dynamic of the unharvested fish population is given by the stochastic logistic growth equation and it is assumed that the fishery harvests the fish population following a constant effort strategy. Explicit formulas for optimal fishing effort are derived in problems considered and the effects of uncertainty, risk aversion and mean reversion speed on fishing efforts are investigated. Fourthly, a Dixit and Pindyck type irreversible investment problem in continuous time is solved, using the assumption that the project value follows a Cox-Ingersoll- Ross process. This solution differs from the two classical cases of geometric Brownian motion and geometric mean reversion and these differences are examined. The aim is to find the optimal stopping time, which can be applied to the problem of extracting resources.

This thesis consists of extensions of results on a perpetual American swaption problem. Companies routinely plan to swap uncertain benefits with uncertain costs in the future for their own benefits. Our work explores the choice of timing policies associated with the swap in the form of an optimal stopping problem. In this thesis, we have shown that Hu, Oksendal's (1998) condition given in their paper to guarantee that the optimal stopping time is a.s. finite is in fact both a necessary and sufficient condition. We have extended the solution to the problem from a region in the parameter space where optimal stopping times are a.s. finite to a region where optimal stopping times are non-a.s. finite, and have successfully calculated the probability of never stopping in this latter region. We have identified the joint distribution for stopping times and stopping locations in both the a.s. and non-a.s. finite stopping cases. We have also come up with an integral formula for the inner product of a generalized hyperbolic distribution with the Cauchy distribution. Also, we have applied our results to a back-end forestry harvesting model where stochastic costs are assumed to exponentiate upwards to infinity through time. / Graduation date: 2013

Submitted by Rafael Dornaus (rdornaus@gmail.com) on 2014-02-27T12:12:05Z No. of bitstreams: 1 Dissertacao_Rafael_Dornaus_final.pdf: 328250 bytes, checksum: 10e077bd9676695e06f4328ff3a2327f (MD5) / Approved for entry into archive by Suzinei Teles Garcia Garcia (suzinei.garcia@fgv.br) on 2014-02-27T12:16:20Z (GMT) No. of bitstreams: 1 Dissertacao_Rafael_Dornaus_final.pdf: 328250 bytes, checksum: 10e077bd9676695e06f4328ff3a2327f (MD5) / Made available in DSpace on 2014-02-27T12:32:37Z (GMT). No. of bitstreams: 1 Dissertacao_Rafael_Dornaus_final.pdf: 328250 bytes, checksum: 10e077bd9676695e06f4328ff3a2327f (MD5) Previous issue date: 2014-01-29 / Este trabalho visa contribuir para a discussão e o instrumental a cerca dos benefícios de controle nas empresas e a forma de estimá-lo. Para tanto, utilizou-se uma abordagem baseada da teoria de opções reais, com foco no diferencial de preço entre classes de ações no Brasil entre janeiro de 2002 a novembro de 2013. Foram examinadas 44 empresas listadas no período, levando a uma amostra de 23.322 observações semanais. Foi encontrada evidência empírica para dar suporte à hipótese da existência de uma opção de venda perpétua sobre os benefícios de controle da empresa de titularidade do controlador da empresa e o efeito negativo que variações no prêmio desta exercem sobre o diferencial de preços entre as classes de ações. Em tempo, também foi encontrada evidência que sugere que o nível de governança corporativa e a proteção aos acionistas minoritários, medidos através do nível de listagem da empresa na BM&FBovespa estão positivamente relacionados com o nível de diferencial de preços. Por outro lado, a inclusão de dados que englobam o período do pós-crise do sub-prime norte-americano não deu suporte para inferir que o nível do diferencial de dividendos exerça pressão positiva no diferencial de preços entre as classes de ações. / This paper aims at contributing to the discussion around private benefits of control and the instrumental to estimate it. Therefore, we analyzed the differential pricing of equity classes in Brazil from January 2002 to November 2013 based on the theory of real options. We examined 44 Brazilian listed firms throughout the period resulting in a sample of 23.322 weekly observations. We found empirical evidence that supports our hypothesis regarding the existence of a perpetual put option on the private benefits of the controlling shareholder and the negative effect its premium deals on the dual-class price differential. We also found evidence suggesting that the level of corporate governance and minority shareholder protection represented by the level of share listing in the BM&FBovespa stock exchange is positively associated with the price differential level. On the other hand, the inclusion of data that covers the post North American sub-prime crisis did not provide evidence that the level dividend differentials is positively related to the dual-class price differential.

O presente trabalho tem como objetivo final a verificação da aplicabilidade da Teoria das Opções Reais (TOR) em investimentos de papel e celulose, considerando o Movimento de Reversão à Média (MRM) nos fatores de risco, dado um modelo de gerenciamento de curto prazo, no âmbito de um estudo de caso da Fibria Celulose S.A. para o setor de papel e celulose no Brasil. Nesta dissertação, testa-se a aderência da série histórica de preços da celulose de fibra curta da Fibria, no período entre 2003 e 2013, a um modelo estocástico de reversão à média, sendo este modelo validado para o presente estudo. Uma vez o modelo validado, determinam-se os parâmetros para realização de cálculos e análises fundamentais para se chegar aos objetivos intermediários, etapa preliminar aos resultados do objetivo final. Dentre os cálculos e análises citados, ressaltam-se: determinação dos VPLs dinâmicos e os valores das Opções Reais europeias sequenciais para a Simulação de Monte Carlo com Processo Neutro ao Risco; construção e análise da Árvore Binomial com Processo Neutro ao Risco; construção e análise das Regiões de Gatilho para preços e lucros marginais em um Processo Real; comparação das Regiões de Gatilho com as determinadas pelas Árvores Binomiais. Assim, com tais análises, confirma-se, nesta dissertação, a aplicabilidade da Teoria das Opções Reais na Análise de Investimento no setor celulósico-papeleiro. / The present work has the ultimate purpose of verifying the applicability of the Real Options Theory in the pulp and paper investment, considering the Mean Reversion Movement in the risk factors, given a short-term management model, within a study of Fibria Celulose S.A. for the pulp and paper industry in Brazil. This dissertation tests the adherence of Fibria's short fiber pulp historical price series, between 2003 and 2013 to a stochastic mean reversion model, being this model validated in the present study. Once the model is validated, the parameters for calculations and fundamental analyzes are determined to reach intermediate goals, preliminary step to the results of the final goal. Among the cited calculations and analyzes, it is emphasized: determination of dynamic NPVs and values of the sequential European Real Options for the Monte Carlo Simulation with Risk Neutral Process; construction and analysis of the Binomial Tree with Risk Neutral Process; construction and analysis of the Trigger Regions for prices and marginal profits in a Real Case; Comparison between Trigger Regions and those determined by the Binomial Trees.So with such analyzes, it is confirmed, in this work, the applicability of the Real Option Theory on Investment Analysis in pulp and paper industry. / Dissertação (mestrado) - Pontifícia Universidade Católica. Departamento de Engenharia Industrial, Rio de Janeiro, 2014. / Bibliografia: p. [109]-113.