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This article presents a framework within which the effects of demographic change on both agglomeration and growth of economic activities can be analyzed. I introduce an overlapping generation structure into a New Economic Geography model with endogenous growth due to learning spillovers and focus on the effects of demographic structures on long-run equilibrium outcomes and stability properties. First, life-time uncertainty is shown to decrease long-run economic growth perspectives. In doing so, it also mitigates the pro-growth effects of agglomeration resulting from the localized nature of learning externalities. Second, the turnover of generations acts as a dispersion force whose anti-agglomerative effects are, however, dampened by the growth-linked circular causality being present as long as interregional knowledge spillovers are not perfect. Finally, lifetime uncertainty also reduces the possibility that agglomeration is the result of a self-fulfilling prophecy. (author's abstract) / Series: Department of Economics Working Paper Series

Rheumatoid arthritis (RA) is an autoimmune disease, which affects 0.5–1.0 % of adults. The aim of this thesis is to study accumulation and localization of endogenous porphyrins by means of spectroscopy and microscopy in experimental rheumatoid arthritis model and postoperative samples of patients after application of 5-aminolevulinic acid or its methyl ester. The spectroscopic measurements of endogenous porphyrins were performed in synoviocytes, chondrons and cartilage explants of patients with RA or osteoarthritis (OA) and in rabbit antigen induced arthritis model. The localization of endogenous porphyrins in synovium and cartilage tissues of rabbit knee joints was determined based on fluorescence spectroscopy, fluorescence intensity and lifetime microscopy, and histology imaging results. Studies showed that selective sensitization of inflamed synovium in the in vitro model may be achieved using ALA and ALA-Me, while in the in vivo model only using ALA-Me. The photosensitizer protoporphyrin IX induced by these precursors is accumulated in the cells of synovium and cartilage tissues. The results presented in this dissertation can be used anticipating to apply the sensitization with endogenous porphyrins for diagnostic and therapeutic purposes in the case of rheumatoid arthritis. / Reumatoidinis artritas (RA) yra autoimuninė liga, kuria pasaulyje serga 0,5-1 % suaugusių žmonių. Disertacijos tikslas – spektroskopiniais ir mikroskopiniais metodais ištirti endogeninių porfirinų susikaupimą ir pasiskirstymą eksperimentinio reumatoidinio artrito modelyje ir pacientų pooperacinėje medžiagoje po 5-aminolevulininės rūgšties (ALA) ar jos metilo esterio (ALA-Me) panaudojimo. Atlikti endogeninių porfirinų fluorescencinės spektroskopijos tyrimai RA ir osteoartritu sergančių (OA) pacientų sinoviocituose, chondronuose ir kremzlės bandiniuose bei triušių antigenu indukuotame artrito modelyje. Endogeninių porfirinų lokalizacija triušių kelio sąnario kremzlės ir sinovijos audiniuose nustatyta remiantis fluorescencinės spektroskopijos, fluorescencijos intensyvumo ir gyvavimo trukmių mikroskopijos bei histologinių vaizdų analizės rezultatais. Tyrimais nustatyta, kad selektyviai sensibilizuoti uždegiminę sinoviją modelyje in vitro galima naudojant ALA bei ALA-Me, o modelyje in vivo tik ALA-Me. Šių pirmtakų indukuotas fotosensibilizatorius protoporfirinas IX yra susikaupęs sinovijos ir kremzlės audinių ląstelėse. Disertaciniame darbe pristatomų tyrimų rezultatai gali būti panaudoti norint ateityje endogeniniais porfirinais pagrįstą sensibilizaciją pritaikyti diagnostikos ir terapijos tikslais reumatoidinio artrito atveju.

The prices of technological equipment have seen significant declines in recent decades. In Chapter 2 of this thesis, we examine the evidence and causes of these price declines. Among several factors, we focus on the learning curve effect where the cost of producing technological equipment declines as the cumulative number of produced units increases. In Chapter 3 we review the literature on technology adoption and the timing decisions of such adoptions. We aim to contribute to the literature by examining the timing of technology adoption under price declines. Furthermore, we consider the effect of human capital on such adoption decisions. We begin in Chapter 4 by developing a model of the timing of technology adoption under an exogenous price decline. Section 1 considers a single price drop in followed by multiple price drops in section 2. From the analytical results developed in these sections, we examine the effect of human capital on the adoption decision. Chapter 5 considers the price of the technological equipment to be endogenous to the model. We run computational experiments to demonstrate the declining price as a function of time. We examine the effect of the distribution of human capital on the price decline and adoption decision of the individuals of the population. We conclude with insights on the relationship between human capital inequality and technology adoption decisions.

The availability of firm level data in international trade started a very quickly developing theoretical literature that focused on the micro evidence and understanding its implications for aggregate productivity and welfare. The new models were dealing with individual firm characteristics determining entry and exit from foreign markets and the different ways in which firms chose to enter. Two of the main features of this literature are that firms have heterogeneous productivities and need to pay a fixed costs in order to enter both their home and foreign markets. As a result, some do not find it optimal to export and it is those with higher productivity that do. This thesis is comprised of three theoretical papers (chapters) in which the models are with firms with heterogeneous productivities and there is steady state economic growth. The purpose in all three papers has been to generate results that are already established empirical facts but that have not been incorporated in the theoretical trade and growth literature. / Diss. Stockholm : Handelshögskolan i Stockholm, 2011

This thesis consists of an introductory chapter and four papers, which relate to environmental policy in the presence of transboundary environmental damage. Paper [I] concerns public policy in a multi-jurisdiction framework with transboundary environmental damage. Each jurisdiction is assumed large in the sense that its government is able to infuence the world-market producer price of the externality-generating good. This gives rise to additional incentives of relevance for national public policy in the non-cooperative Nash equilibrium. With the uncoordinated equilibrium as the reference case, the welfare effects from coordinated changes in public policy variables are analyzed. Paper [II] analyses welfare effects of coordinated changes in environmental and capital taxation in the presence of transboundary environmental externalities and wage bargaining externalities. In the wage bargaining between frms and labor unions, firms use the threat of moving abroad to moderate wage claims, which means that domestic policy infuences wage formation abroad. The specific framework implies welfare effects of policy coordination that correspond to each of the respective international interaction mentioned above. In paper [III], national governments face political pressure from environmental and industrial lobby groups, while pollution taxes are determined in an international negotiation. It is shown that a general increase in the environmental concern and the weight the governments attach to social welfare both tend to increase the pollution tax. However, allowing for asymmetries between the countries means that a general increase in the environmental concern has the potential to reduce the pollution tax. Paper [IV] studies national environmental policies in an economic federation characterized by decentralized leadership. The federal government sets emission targets for each member country, which are implemented by the national governments. Although all national governments have commitment power vis-à-vis the federal government, one of them also has commitment power vis-à-vis the other member countries. This creates incentives to act strategically toward the federal government, as well as toward other members.

Thesis (Ph. D.)--University of Virginia, 2008. / Includes bibliographical references. Also available online through Digital Dissertations.

Zugl.: Diss. Univ. Duisburg-Essen, 2006.

A presente tese é constituída de três ensaios que abordam duas relevantes questões que estão intrinsecamente relacionadas em macroeconomia: política monetária e inflação. No primeiro ensaio, nós procuramos averiguar não linearidades na função de reação do Banco Central do Brasil (BCB) através da estimação de regressões quantílicas inversa, sugerido por Wolters (2012) e proposto por Chernozhukov and Hansen (2005, 2006). Este método nos possibilitou detectar não linearidades na função de reação do BCB sem a necessidade de fazer suposições específicas acerca dos fatores que determinam essas não linearidades. Em específico, nós observamos que: i) a resposta da taxa de juros ao hiato da inflação corrente e esperada foi, em geral, mais forte na parte superior da distribuição condicional da taxa de juros Selic; ii) a resposta ao hiato do produto apresentou uma tendência crescente e significativa na parte inferior da distribuição condicional da taxa Selic; iii) a resposta do BCB à taxa de câmbio real foi positiva e mais elevada na cauda superior da distribuição condicional da taxa Selic. No segundo ensaio, nós investigamos a existência de não linearidades na função de reação do Banco Central do Brasil (BCB) decorrentes de incertezas desse policymaker acerca dos efeitos do hiato do produto sobre a inflação. Teoricamente, nós seguimos Tillmann (2011) para obter uma regra de política monetária ótima não linear que é robusta às incertezas acerca do trade-off produto-inflação na curva de Phillips. Além disso, nós realizamos testes de quebra estrutural para avaliar possíveis mudanças na condução da política monetária brasileira durante o regime de metas de inflação. Os resultados indicaram que: i) as incertezas acerca da inclinação na curva Phillips implicaram em não linearidades na função de reação do BCB; ii) não se pode rejeitar a hipótese de uma quebra estrutural nos parâmetros da regra monetária ocorrendo no terceiro trimestre de 2003; iii) houve um aumento na resposta da taxa Selic ao hiato do produto e uma redução da reação ao hiato da inflação corrente no regime Meirelles- Tombini; e iv) o BCB também tem reagido à taxa de câmbio durante o regime Meirelles- Tombini. No terceiro ensaio, nós procuramos analisar os determinantes da inflação no Brasil através da estimação da Curva de Phillips Novo-Keynesiana (CPNK) proposta por Blanchard e Galí (2007) e a versão padrão proposta por Galí e Gertler (1999). Além disso, realizamos testes de quebras estruturais para avaliar possíveis mudanças na dinâmica da inflação brasileira durante o período de 2002 a 2014. Os resultados indicaram que: i) os testes de quebra estrutural apontam a existência de pelo menos uma mudança estrutural nos coeficientes da CPNK; ii) o componente forward-looking da inflação é dominante, embora sua relevância tenha sido reduzida após 2004; iii) a taxa de desemprego tem afetado negativamente a inflação, embora seja observado uma redução desse impacto nos últimos anos; iv) as mudanças na taxa de câmbio apenas tiveram efeitos sobre a inflação na primeira subamostra e tem perdido relevância no período mais recente; v) o efeito do hiato do produto sobre a inflação corrente diminuiu nos anos recentes; vi) em geral, nós rejeitamos a hipótese nula de uma curva de Phillips vertical no longo prazo a um nível de significância de 5%, mas não a 1%. / This thesis is composed of three essays to address two important issues that are intricately related in macroeconomics: monetary policy and inflation. In the first essay, we seek to investigate nonlinearities in the reaction function of the Central Bank of Brazil (CBB) by estimating inverse quantile regressions (IVQR), suggested by Wolters (2012) and proposed by Chernozhukov and Hansen (2005, 2006). This method enabled us to detect nonlinearities in the CBB’s reaction function without the need to make specific assumptions about the factors that determine these nonlinearities. In particular, we observed that: i) the response of the interest rate to the current and expected inflation was, in general, stronger in the upper tail of the conditional interest rate distribution; ii) the response to the output gap showed a growing and significant trend in the lower tail of the conditional Selic rate distribution; iii) the response of the CBB to the real exchange rate was positive and higher in the upper tail of the conditional Selic rate distribution. In the second essay, we investigate the existence of nonlinearities in the reaction function of the Central Bank of Brazil (CBB) arising from this policymaker’s uncertainties about the effects of the output gap on inflation. Theoretically, we follow Tillmann (2011) to obtain a nonlinear optimal monetary policy rule that is robust to uncertainty about the output-inflation trade-off of the Phillips Curve In addition, we perform structural break tests to assess possible changes in the conduct of the Brazilian monetary policy during the inflation-targeting regime. The results indicate that: i) the uncertainties about the slope in the Phillips curve implied nonlinearities in the CBB’s reaction function; ii) we cannot reject the hypothesis of a structural break in the monetary rule parameters occurring in the third quarter of 2003; iii) there was an increase in the response of the Selic rate to output gap and a weaker response to the current inflation gap in Meirelles Tombini’s administration; and iv) the CBB has also reacted to the exchange rate in Meirelles-Tombini’s administration. In the third essay, we proposed to analyze the determinants of inflation in Brazil through the estimation of the new Keynesian Phillips curve (NKPC) proposed by Blanchard and Galí (2007) and the standard version proposed by Galí and Gertler (1999). In addition, we perform structural break tests to assess possible changes in the dynamics of inflation in Brazil during the period 2002 to 2014. The results indicated that: i) structural break tests indicate the existence of at least one structural change in the coefficients of NKPC ; ii) the forward-looking component of inflation is dominant, though its importance has been reduced after 2004; iii) the unemployment rate has negatively affected inflation, although a reduction of this impact has been observed in recent years; iv) changes in the rate of exchange only had effects on inflation in the first subsample and losing relevance in the most recent period; v) the effect of the output gap on the current inflation has declined in recent years; vi) overall, we reject the null hypothesis of a vertical Phillips curve in the long term at a significance level of 5%, but not 1%.

Cette thèse étudie le choix de portefeuille et l'évaluation d'actifs avec des préférences qui vont au-Delà des préférences d'espérance d'utilité et de moyenne-Variance standard. La première partie de cette thèse porte sur un modèle de décision dans lequel le décideur forme des croyances endogènes compte tenu de son utilité d'anticipation et de sa déception à posteriori. Les implications du modèle en termes de choix de portefeuille et d'évaluation d'actifs sont dérivées et comparées aux implications du modèle d'espérance d'utilité standard. La deuxième partie de cette thèse porte sur des investisseurs qui dérivent l'utilité des trois premiers moments du rendement de leur portefeuille. Nous dérivons et testons les conditions sous lesquelles des actifs supplémentaires peuvent améliorer l'univers d'investissement des investisseurs avec des préférences moyenne-variance-skewness. Les implications de ces préférences pour les rendements d'actifs à l'équilibre sont ensuite analysées et testées avec des rendements boursiers. / This thesis studies portfolio choice and asset pricing with preferences which go beyond the standard expected utility and mean-Variance preferences. The first part of this thesis analyses a decision model in which the decision maker forms endogenous beliefs given his anticipation utility and his ex-Post disappointment. Portfolio choice and asset pricing implications of the model are derived and compared to the implications of the standard expected utility framework. The second part of this thesis analyses investors choice when preferences are derived from the first three moments of portfolio returns. We derive and test the conditions under which additional assets can improve the investment opportunity set of investors with mean-Variance-Skewness preferences. The implications of these preferences for the equilibrium cross-Section of asset returns are then analyzed and tested with stock returns.