Τις τελευταίες δεκαετίες η υψηλή μεταβλητότητα που παρατηρείται στις χρηματοοικονομικές μεταβλητές, έχει δημιουργήσει έντονη την ανάγκη για αποτελεσματική διαχείριση του κινδύνου. Τα παράγωγα χρηματοοικονομικά προϊόντα παρέχουν τα μέσα για αντιστάθμιση του κινδύνου. Προς αυτή την κατεύθυνση έχει κατασκευασθεί ένας δείκτης που αντιπροσωπεύει την τεκμαρτή μεταβλητότητα των παραγώγων χρηματοοικονομικών προϊόντων, ο δείκτης VIX. Σκοπός της εργασίας είναι η διερεύνηση της σχέσης του δείκτη VIX με την αγορά του S&P500 και η σχέση συνολοκλήρωσης τεκμαρτής και δεσμευμένης μεταβλητότητας του S&P500. / --

Researchers tend to disagree on the direction of the relation among R&D and economic growth, suggesting that if economic performance determines R&D investments countries might overinvest in their R&D expenditure. The purpose of this thesis is therefore to shed new light to this question by first establishing a relation among the variables and thereafter investigate the Granger causality between them. This paper is based on a panel study consisting of 60 countries, with various levels of income during the period 1996-2015. Using a fixed effects model, we can establish a positive relation between growth in R&D expenditure and GDP growth and using Granger causality tests and the Toda-Yamamoto augmented Granger causality tests, we can conclude that the growth of R&D expenditure determines economic performance in the short-run for countries in all income levels, however no conclusions can be made regarding the direction of Granger causality in the long-run. Hence, our results show that R&D investments stimulate economic growth and should, to some extent, be favoured by policy regardless of a nation's level of development.

This thesis investigates the short term and the long term cointegration relations between European and Chinese, European and Russian stock markets, with a goal to define international diversification benefits. Whereas Russia and China are considered as developing countries, Europe represents a developed market. The period of study is from 1997 to 2018, which considers the global 2007-2008 financial crisis as a shift in the equilibrium.The static cointegration long run findings demonstrate scope for diversification benefits for the all observing markets over the whole period. With regard to the sub periods (before and after the global financial crisis), the outcomes suggest increase in cointegration relations between Europe and China after the crisis, indicating a more diversified portfolio for investors before the crisis. European and Russian financial time series show no changing in cointegration linkages after the crisis, suggesting scope for diversification gains before and after the crisis in the long run.The dynamic cointegration results, however, demonstrate episodic cointegrating relations over the whole period for the all markets. These findings also clear illustrate growth in cointegration linkages during the first year of the crisis for all samples, suggesting a less diversified portfolio during this period (for the short horizon investors), and supporting the financial contagion effect in the short run.Looking at static and dynamic results, we recommend combining both methods in order to make a clear conclusion about benefits from international diversification.

Background: In 2008, the financial crisis led to the deterioration of the global economy. The financial industry suffered severe setbacks. On the one hand, regulators strengthened their supervision over financial institutions and raised capital requirements. On the other hand, publics’ confidence in financial institutions declined. At the same time, the fintech industry has rapidly developed during this decade, they use technology to make financial innovation and pose a threat to the traditional financial industry. Purpose: This paper aims to study the linkage between U.S. fintech and the traditional financial sector, trying to figure out which industry's stock price changes will affect the stock price changes in another industry. In particular, it also considers whether the global financial crisis will affect this relationship. Method: We first perform the Granger causality test under the VAR framework for several selected indices sequences, and then use the Toda Yamamoto version of Granger causality approach to verify the reliability of the above tests. Testing is divided into different time intervals in order to detect the impact of financial crisis on the relationship between time series. Conclusion: The empirical analysis results show that the correlation between the index in the long-term and short-term is inconsistent, and also shows that the correlation between the index will be affected by the financial crisis, or say, it will change as time varying.

Previous work has linked the onset and progression of Alzheimer’s Disease (AD) to changes in the Default Mode Network (DMN), including greater atrophy within the hippocampus (HC) as well as diminished functional connectivity and effective connectivity between anatomical DMN structures. Animal models have described the HC as a primary region of interest in studying the effects of exercise on adult neurogenesis and memory performance. Human studies have demonstrated that aerobic exercise leads to greater cardiorespiratory fitness and improved functional connectivity in the DMN for healthy adults. The goal of this study is to go beyond the predictions of human and animal studies to investigate how cardiorespiratory fitness may be used to estimate effective connectivity between the HC and the other DMN structures for young adults using resting state fMRI. Due to the data driven nature of this study, no hypothesis has been formulated. To investigate, data from 25 sedentary young adults was analyzed. Data included a resting state fMRI procedure and a cardiorespiratory fitness test, each taken from part of a larger ongoing clinical trial in the Brain Plasticity and Neuroimaging (BPN) Lab at Boston University (BU). We utilized group independent component analysis (GICA) to identify the regions that define the DMN and Conditional Granger Causality Analysis (CGCA) to determine effective connectivity between these regions. GICA indicated 9 structural regions in the DMN, consistent with previous work. This resulted in 72 possible instances of effective connectivity. The difference of causal influence between regions was calculated for each pair of DMN regions for CGCA, resulting in 36 possible instances of causal connectivity. Linear regression models were created to analyze the effect of cardiorespiratory fitness on effective connectivity between DMN regions and found 11 linear models which exhibited a significant (p > 0.05) relationship. Eight of eleven models involved the left or right hippocampus, showing that greater cardiorespiratory fitness is correlated with changes effective connectivity between the HC and the PCC, MPFC, or LTC. These results provide proof of concept that cardiorespiratory fitness in young adults is associated with changes DMN effective connectivity, particularly involving the hippocampus. This adds to the literature suggesting extended aerobic exercise, which is known to increase cardiorespiratory fitness and has been shown to increase the volume of the HC in older adults, may be neuroprotective of the HC across the lifespan. Further investigation is required to explore how effective connectivity in the DMN changes following an aerobic exercise intervention.

Quantum theory describes our universe incredibly successfully. To our classically-inclined brains, however, it is a bizarre description that requires a reimagining of what fundamental reality, or 'ontology', could look like. This thesis examines different ontological features in light of the success of quantum theory, what it requires, and what it rules out. While these investigations are primarily foundational, they also have relevance to quantum information, quantum communication, and experiments on quantum systems. The way that quantum theory describes the state of a system is one of its most unintuitive features. It is natural, therefore, to ask whether a similarly strange description of states is required on an ontological level. This thesis proves that almost all quantum superposition states for d > 3 dimensions must be real - that is, present in the ontology in a well-defined sense. This is a strong requirement which prevents intuitive explanations of the many quantum phenomena which are based on superpositions. A new theorem is also presented showing that quantum theory is incompatible with macro-realist ontologies, where certain physical quantities must always have definite values. This improves on the Leggett-Garg argument, which also aims to prove incompatibility with macro-realism but contains loopholes. Variations on both of these results that are error-tolerant (and therefore amenable to experimentation) are presented, as well as numerous related theorems showing that the ontology of quantum states must be somewhat similar to the quantum states themselves in various specific ways. Extending these same methods to quantum communication, a simple proof is found showing that an exponential number of classical bits are required to communicate a linear number of qubits. That is, classical systems are exponentially bad at storing quantum data. Causal influences are another part of ontology where quantum theory demands a revision of our classical notions. This follows from the outcomes of Bell experiments, as rigorously shown in recent analyses. Here, the task of constructing a native quantum framework for reasoning about causal influences is tackled. This is done by first analysing the simple example of a common cause, from which a quantum version of Reichenbach's principle is identified. This quantum principle relies on an identification of quantum conditional independence which can be defined in four ways, each naturally generalising a corresponding definition for classical conditional independence. Not only does this allow one to reason about common causes in a quantum experiments, but it can also be generalised to a full framework of quantum causal models (mirroring how classical causal models generalise Reichenbach's principle). This new definition of quantum causal models is illustrated by examples and strengthened by it's foundation on a robust quantum Reichenbach's principle. An unusual, but surprisingly fruitful, setting for considering quantum ontology is found by considering time travel to the past. This provides a testbed for different ontological concepts in quantum theory and new ways to compare classical and quantum frameworks. It is especially useful for comparing computational properties. In particular, time travel introduces non-linearity to quantum theory, which brings (sometimes implicit) ontological assumptions to the fore while introducing strange new abilities. Here, a model for quantum time travel is presented which arguably has fewer objectionable features than previous attempts, while remaining similarly well-motivated. This model is discussed and compared with previous quantum models, as well as with the classical case. Together, these threads of investigation develop a better understanding of how quantum theory affects possible ontologies and how ontological prejudices influence quantum theory.

O objetivo desta dissertação será analisar a dinâmica do processo de integração financeira entre o mercado acionário brasileiro e o norte americano. Buscaremos identificar a relação de interdependência entre os dois mercados acionários ao longo do tempo por meio de testes de cointegração, e de causalidade de Granger com rolling windows, e através de um modelo de correção de erros estimado por meio do filtro de Kalman. Por fim, verificaremos se as séries temporais obtidas nos procedimentos iterativos possuem relação com a volatilidade ou quantidade de negócios dos contratos analisados. Evidenciamos nesta dissertação que a relação de integração financeira observada apresenta caráter variável ao longo do tempo. Isso vale tanto para a relação de cointegração, quanto para a relação de causalidade de Granger entre as séries temporais observadas. Evidenciamos também que a volatilidade das séries apresenta uma relação positiva e significativa com a relação de cointegração observada através dos testes de cointegração por meio de rolling windows. / The aim of this dissertation is to analyze the dynamics of financial integration between the Brazilian and the North American stock market. We will seek to identify the interdependence relationship between the two stock markets over time using rolling cointegration tests, rolling Granger causality tests, and estimating an error correction model using Kalman filter. Finally, we look if the time series obtained in the iterative procedures are related to volatility or quantity of trades from the contracts. We show in this dissertation that the financial integration relationship observed has a time varying character over time. This goes for both the cointegration relationship, and for the Granger causality relationship between the observed time series. We show also that the volatility of the time series has a positive and significant relationship with the cointegration relationship observed through the rolling cointegration tests.

Food inflation in South Africa has been viewed as an important source of underlying inflationary pressures in the economy due to its persistence beyond that of other commodities. Although several studies found food to be one of the factors that influence purchase decisions, there still appears to be an absence of research that directly links food inflation to consumers’ decisions, especially when financing the purchase of new passenger vehicles in South Africa. In this regard, this study investigated whether the increase in the prices of food products has a significant effect on passenger vehicle purchases in South Africa. Leaning on the literature that argues that economic factors do not play much of a role in passenger vehicle purchase decisions in South Africa, it was hypothesised that there is no supported relationship between food inflation and passenger vehicle purchases in South Africa. Using secondary time series data, the Pearson correlation test revealed a negative but insignificant relationship between food inflation and vehicle purchases in South Africa. The ordinary least squares estimate of the purchase function, taking into account several economic factors that influence passenger vehicle purchase decisions in the literature, showed that disposable income of households along with vehicle purchases of the previous period are to be considered as main determinants of vehicle purchases in South Africa. In addition, it was also revealed that new vehicle prices are also a significant determinant of vehicle purchases. The Johansen cointegration test revealed that the variables in the vehicle purchase function were cointegrated in the long run. The vector error correction model showed a long-run relationship, albeit insignificant, between food inflation and vehicle purchases and no relationship between the two variables in the short run. The Granger causality test revealed that food inflation and vehicle purchases are independent from each other, meaning that no causal effect was found between the variables, regardless of the direction of the test. This study concluded that economic factors such as interest rate and fuel price have an insignificant influence on passenger vehicle purchases in South Africa. In the same line, the impact of food inflation on passenger vehicle purchases in South Africa was found to be insignificant, therefore, the conclusion was drawn that the increase in the prices of food products will not play a considerable role in consumers’ decisions regarding passenger vehicle purchase in South Africa. / Business Management / M. Com. (Business Management)

In this study of causal decision-making, a video game was adapted to explore factors affecting causal judgment in a dynamic setting. In the experiment, participants were presented with groups of potential targets. Causal delay and number of alternatives were varied. The participants were tasked with discriminating which one of the potential targets was producing a secondary event in the form of distal explosions on objects that the participant was instructed to preserve. Choice accuracies and latencies were recorded for each participant. For the analysis, choice accuracies were converted into discriminability metrics using signal detection theory. The experiment revealed a main effect of delay on discriminability but no effect of the number of alternatives. There were main effects of the number of alternatives, sex, as well as a Delay × Number of alternatives interaction on latency. The results suggest that discriminability is maintained across different numbers of targets by compensating with longer observation times.

Submitted by Andrea Hayashi (deachan@gmail.com) on 2016-06-22T14:34:41Z No. of bitstreams: 1 dissertacao-roberto-de-sousa-silva.pdf: 1107545 bytes, checksum: 1eb94eb7d6c36b557c5a8fc8efe9c693 (MD5) / Approved for entry into archive by Andrea Hayashi (deachan@gmail.com) on 2016-06-22T14:35:23Z (GMT) No. of bitstreams: 1 dissertacao-roberto-de-sousa-silva.pdf: 1107545 bytes, checksum: 1eb94eb7d6c36b557c5a8fc8efe9c693 (MD5) / Made available in DSpace on 2016-06-22T14:35:23Z (GMT). No. of bitstreams: 1 dissertacao-roberto-de-sousa-silva.pdf: 1107545 bytes, checksum: 1eb94eb7d6c36b557c5a8fc8efe9c693 (MD5) Previous issue date: 2014-06-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Duns Scotus, teólogo padre franciscano e filósofo do século XIII busca provar a existência de Deus através da questão “se há entre os entes um ente infinito atualmente existente” (Ordinatio I, parte 1, qq. 1-2.). O Doutor Sútil elabora uma prova dentre as mais complexas, por isso, não é uma prova fácil de ser analisada, mesmo porque temos no mínimo quatro versões: na Lectura (I, d. 2, q. 1, nn. 38- 135), na Ordinatio (I, d. 2, q. 1, nn. 1-156), na Reportatio (I, d. 2, q. 1) e no De primo principio. Vê-se que o tema é um dos problemas centrais da filosofia scotista. Nossa pesquisa enxerga na Ordinatio I (d. 2, q. 1) uma versão completa e madura da prova da existência de Deus em Scotus, além de ser uma edição crítica da resposta do mestre franciscano à questão. Por isso, é aquela que em especial exploraremos. Nessa obra, Scotus argumenta sobre a prova da existência de um princípio absolutamente simples, que seria primeiro na ordem de causalidade eficiente e final. Em seguida, demonstra que esse ente absolutamente simples é plenamente primeiro, pois é primaz em eficiência, finalidade e eminência. Também procura provar que essa tríplice primazia cabe a uma única natureza. Portanto refere-se a um único ente descrito como infinito, pois o primeiro em causalidade só pode causar a si mesmo e ser causa por si mesmo, não é causado por nada externo. Esse ente só pode ter a si mesmo como finalidade, pois, do contrário, não seria primeiro. Do mesmo modo, ele só pode ser primaz em eminência, senão não seria primeiro. Uma vez provadas a unidade e simplicidade desse ente, Scotus parte para a demonstração das propriedades absolutas de Deus. Ele as vê em duas partes: na primeira, trata da inteligência e vontade, e na segunda, da infinidade desse primeiro ente. Logo em seguida, iremos explorar os argumentos de Scotus que corroboram a afirmação da Unicidade de Deus que ele trata na Ordinatio I, parte I questão 3. / Duns Scotus, Franciscan Priest Theologian and Philosopher of the Thirteenth Century seeks to prove the existence of God through the question “If there is an infinite being among beings that actually exists" (Ordinatio I, part 1, qq. 1-2 . ). The Subtle Doctor elaborates a proof from among the more complex ones, so it is not an easy proof to analyze. We have at least four versions: in Lectura (I, d. 2, q. 1, nn. 38- 135) in the Ordinatio (I, d. 2, q. 1, nn. 1-156) in Reportatio (I, d. 2, q. 1) and the De primo principio, One sees that the theme is one of the core problems of the Philosophy Scotist. Our research sees in the Ordinatio I (d. 2, q. 1) a complete and mature version of proving the existence of God at Scotus, besides being a critical edition of Master Franciscan to reply the question. Therefore, the one that we will explore. In that work, Scotus proves the existence of a principle simple, that it would be the first about efficient causality and final. Then he demonstrates that this being simple is fully first, as its primacy in efficiency, finality and eminence. In addition, he seeks to prove that this threefold primacy belongs to one nature. He refers to a single entity described as infinite. This being can only have itself as purpose, because otherwise it would not be first. Similarly, it must be the first one in eminence, otherwise would not be the first. Once proven the unity and simplicity of this being, Scotus will demonstrate the absolute properties of God. He sees into two parts: the first deals with the intellect and will, and the second part deals with the infinity of this first being. Next, we will be exploring the arguments from Scotus that backs the Unity of God that he treats in Ordinatio I, Part I Question 3.