Environnement et activités humaines interagissent à travers des relations multiples et complexes. Cette thèse s’interroge sur les limites que l’environnement pourrait imposer à la croissance. Le premier chapitre montre que l’environnement peut constituer un frein au développement en diminuant l’espérance de vie des agents, en freinant leur épargne, et peut causer des situations de trappes à pauvreté environnementales. La mise en place de politiques environnementales publiques peut néanmoins permettre d’éviter ces trappes et d’augmenter le niveau de revenu par tête. Dans le second chapitre,l’existence de ressources non-renouvelables polluantes nécessaires à la production est susceptible de freiner la croissance. Cependant, dans la lignée des travaux néoclassiques des années 70, les difficultés liées au caractère fini des ressources peuvent être dépassées par un progrès technologique exogène et des possibilités de substitution capital-ressources suffisantes. Il est par ailleurs démontré qu’une pollution non-persistante provenant de l’utilisation des ressources ne constituait pas un frein au développement. Enfin, le troisième chapitre démontre qu’une forte dépendance aux ressources naturelles affecte négativement la croissance des pays en développement, tandis que l’abondance en ressources naturelles la favorise. La dépendance étant le résultat de choix économiques, une politique de diversification de l’économie consistant à réinvestir les rentes issues de l’exploitation des ressources naturelles dans les secteurs secondaire et tertiaire pourrait permettre de la réduire. Par ailleurs, nous suggérons que développer l’éducation, les institutions et les marchés financiers pourrait permettre de limiter le risque de malédiction des ressources. / Human activities and the environment interact through multiple and complex relations. Can the natural environment be viewed as a limit to growth ? This thesis tries to develop answers to this crucial question.The first chapter shows that environmental degradations may constitute a brake on growth diminishing life expectancy, and thus savings. It also shows that environmental poverty traps may exist. However,public environmental policies may help countries to escape from such traps, and to reach a higher level of income per capita. In the second chapter, we suggest that the existence of polluting non-renewable resources necessary for production may hamper growth. However, we show that flow pollutions caused by the use of resources can’t be seen as a development brake. Then, following neoclassical works of the1970s, we confirm that exogenous technological progress and sufficient substitution possibilities mayal low to overcome difficulties linked to the exhaustibility of resources. Finally, the third chapter demonstrates that, in low-income economies, strong resource dependency dampens growth while abundanceis growth promoting. Dependence is the outcome of economic choices. Thus a diversification policy that consists on investing the rent in secondary and tertiary sectors may help reduce dependence. Finally, we suggest that the development of education, institutions, and financial markets may allow to decrease the probability to experience a resource curse.

This thesis consists of three essays, which all concern the dynamics of pension reform. The first essay evaluates the financial balance and the demographic adjustability of the reformed Swedish pay-as-you-go pension system. The main findings are that the demographic adjustability of the system is poor. Furthermore, the financial balance and pension levels are, to a large degree, dependent on the pension fund and its returns. Making some alterations to the system's benefit formula may improve the adjustability of the system, as well as decreasing its pension fund dependency. It is also shown that the new public system imposes an age-dependent implicit tax on labor earnings that is falling with age. Within the pay-as-you-go system, this tax is large for younger workers for whom almost the whole contribution is regarded as a tax. By introducing a public defined contribution system, the total implicit tax may be reduced since the defined contribution system implies a negative implicit tax because savings are subsidized within the defined contribution system. In the second essay a three-generation OLG model for analyzing a privatization of PAYG old-age social security is developed. Furthermore, it proposes an explicit reform for how the privatization transition may be undertaken. The set of government policy instruments is limited to debt issuing and proportional labor income taxation. The possibilities of a Pareto-improving privatization, given the proposed reform, are then analyzed. Contrary to models where a two-generation OLG framework is used, the three-generation framework creates possibilities for a Pareto-improving privatization of old-age social security, since the PAYG system induces a non-optimal implicit tax over the life cycle. By shifting to an optimal tax policy cannot only the pension claims accrued under the PAYG system be financed, but the shift will also be Pareto-improving. In the third essay the performance of the reformed Latvian pay-as-you-go pension system is evaluated against the background of an exceptional projected decrease in the Latvian labor force. The pension system is designed to handle the upcoming difficulties, and special attention has been given in the design to keep the expenditures low relative to the revenues, by introducing rules dampening the increase in the pension expenditures. In the light of the pessimistic projection of the Latvian demography, the newly reformed PAYG system performs remarkably well. The expenditure reducing rules introduced have significant effects on the system's financial balance. The pension reform also includes the launch of a publicly run defined contributions pension system. It is shown that the resulting implicit tax imposed by the public pension system imposes on labor earnings is negative and increasing with age. That is, savings are subsidized in the public pension system. It is also shown that private savings are fully crowded out as individuals try to offset their savings in the pension system. Since individuals are capital constrained, they will have no private assets at all. From a welfare perspective, this suggests the overall contribution rate to the public pension system to be too high. / <p>Diss. Stockholm : Handelshögskolan, 2002</p>

The aim of this study is to analyse the impacts of the social security system reform performed in Turkey within the

Calif., Univ., Dep. of Economics, Diss.--Stanford, 2002. / Kopie, ersch. im Verl. UMI, Ann Arbor, Mich.

Univ., Diss.--Bonn, 2002.

Univ., Fak. für Wirtschaftswiss., Diss.--Magdeburg, 2002. / Literaturverz. S. [269] - 296.

Submitted by Haroudo Xavier Filho (haroudo.xavierfo@ufpe.br) on 2016-03-01T16:57:56Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 2015, Desoneração da folha de pagamentos -final- Carlos Eduardo - final.pdf: 1472443 bytes, checksum: 40ab31bfa833ed1d099a25ceb24fc326 (MD5) / Made available in DSpace on 2016-03-01T16:57:56Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 2015, Desoneração da folha de pagamentos -final- Carlos Eduardo - final.pdf: 1472443 bytes, checksum: 40ab31bfa833ed1d099a25ceb24fc326 (MD5) Previous issue date: 2015-06-13 / CAPES / Neste trabalho, apresentaremos políticas tributárias com o intuito de avaliar o impacto de longo prazo da desoneração da folha de pagamentos sobre consumo agregado, o estoque de capital, produto e o bem-estar entre gerações. Para isso, utilizaremos o modelo de gerações sobrepostas (Overlapping Generations Models) com vida finita, probabilidade de morte e previdência social. A inovação dessa pesquisa frente a literatura, foi a simulação com alíquota zero sobre a contribuição patronal, a incorporação da despesa da previdência e do fator previdenciário. Com essas modificações, temos um modelo próximo da economia brasileira. Os resultados apontaram que a desoneração da folha de pagamentos provocou aumentos no produto, capital e consumo de longo prazo, sem grandes sacrifícios para a economia no curto prazo. / In this work, we present tax policies in order to assess the impact of long-term relief payroll on aggregate consumption, the stock of capital, product and welfare between generations. For this, we use the model of overlapping generations with finite life, risk of death and social security. The innovation of this research literature forward was the simulation with zero tax rate on the employer's contribution, the incorporation of the social security expense and the social security factor. With these changes, we have a model close to the Brazilian economy. The results showed that the relief payroll caused increases in product, capital and long-term consumption without major sacrifice for the economy in the short term.

A two-sector OLG model illuminates the intergenerational effects of a tax that protects an environmental stock. A traded asset capitalizes the economic returns to future tax-induced environmental improvements, benefiting the current asset owners, the old generation. Absent a transfer, the tax harms the young generation by decreasing their real wage. Future generations benefit from the tax-induced improvement in environmental stock. The principal intergenerational conflict arising from the tax is between generations alive at the time society imposes the policy, not between generations alive at different times. A Pareto-improving tax can be implemented under various political economy settings. (authors' abstract)

The demographic structure seems to change dramatically over the next 50 years in the Czech Republic. The aim of this study is to assess the impact of expected demographic changes on the future development of a real interest rate and international capital flows. In order to simulate the impact of the expected demographic changes upon the mentioned variables we apply a computable overlapping generations model. The real interest rate development is simulated under a closed economy assumption. As a result of the future expected demographic changes labour-capital ratio tends to fall, i.e. the real interest rate diminishes. The range of a change is significantly affected by a public budget closure rule. In case of an endogenous income tax rate, the real interest rate falls down by 0.5 percentage point. On the contrary, the real interest rate decreases by almost 1 percentage point in case when public transfers adjusted. Assuming an open economy, we simulate the impact of the expected demographic changes on the international capital flows between the domestic economy and the rest of the world. In case of increasing ratio of older agents, the aggregate domestic wealth surpasses the demand for capital by domestic firms. As a result a part of domestic capital is exported abroad. Increasing level of net foreign assets contributes to positive change in ratio of the balance of payment to the domestic production in a range from 2 to 5 percentage points over next 40 years if income taxes or public transfers change respectively.

Fisher’s adaptive sex ratio theory predicts that organisms should invest equally in sons and daughters and the sex ratio at conception should be 1:1. Hamilton’s theory predicts that organisms should adjust sex ratios based on the relative strength of competition within a mating group. Testing sex ratio and sex allocation theories requires variation in sex ratio. Different sex allocation and sex allocation adjustment mechanisms can produce skewed sex ratios. I used Tigriopus californicus, a harpacticoid copepod with extrabinomial variation in sex ratios, to test sex ratio evolution and socially-mediated sex determination. Using artificially selected sex-biased populations, the trajectory of population sex ratios were as expected under Fisher’s theory and sex ratios approached/reached 0.5 proportion males. Populations with overlapping generations had a slower rate of change towards 0.5 than populations with non-overlapping generations. I show that these data are supported by multiple different models: a mechanistic and simulation model. I tested socially-mediated sex determination using seawater conditioned with different local sex ratios of copepods. There were detectable effects found in both wild populations and isofemale lines. However, these effects may be trivial as differences were small between treatments. Sex determination in T. californicus is a complex mechanism, with multiple genetic and environmental components. The complex nature of sex determination in T. californicus and the dynamic nature of their habitat in highly ephemeral splash pools provide a possible explanation for the non-Fisherian sex ratios we see. / Graduate