National Labor Markets, International Factor Mobility and Macroeconomic Instability

We consider a standard two—country environment, where one of the countries has rigid wages and unemployment, and analyze how factor markets’ integration affects the economy with respect to expectationsdriven fluctuations. We demonstrate that by allowing free capital mobility, indeterminacy is exported to the world economy. If further liberalization is permitted, by allowing free movements of labor, the scope for indeterminacy is reduced and open labor markets may produce a stabilizing effect on the global macroeconomy. Whether this also implies higher welfare in the long run depends on differentials in average firm size across countries.Indeterminacy, Factor Movements, Globalization, Efficiency Wages

Enterococcus and biocides: mechanisms of tolerance and selection for vancomycin resistance

Dissertation presented to obtain a Doctoral degree in Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa.Biocides are chemical agents, generally with a broad-spectrum of activity, used to destroy, render harmless, prevent the action of, or otherwise exert a controlling effect on any harmful organism. Biocidal products comprise several chemical groups. Among the most commonly used are alcohols, aldehydes, biguanidines (e.g. chlorhexidine), phenols (e.g. triclosan) and quaternary ammonium compounds (e.g. benzalkonium chloride). Although some of the biocides were discovered many years ago, their generalised use began only some decades ago. They are used for cleaning and/or disinfecting in many different environments, such as in hospital facilities, veterinary facilities, food and pharmaceutical industry sites and in our homes. Biocides are also incorporated in several products as preservatives, such as deodorants, body creams and soaps. Some of the environments where biocides are applied are shared with enterococci.(...)Financiall support by Fundação para a Ciência e Tecnologia (FCT), POCI 2010 and Fundo Social Europeu (FSE); BD nº SFRH/BD/41882/2007

Expected Inflation, Sunspots Equilibria and Persistent Unemployment Fluctuations

We propose and estimate a model where unemployment fluctuations result from self-fulfilling changes in expected inflation (sunspot shocks) affecting nominal wage bargaining. Since the estimated parameters fall near the locus of Hopf bifurcations, country-specific expected inflation shocks can replicate the strong persistence and heterogeneity observed in European unemployment rates. They also generate positive comovements in macroeconomic variables and a large relative volatility of consumption. All these features, hardly accounted for by standard sunspot-driven models, are explained here by the fact that liquidity constrained workers, facing earnings uncertainty in the context of imperfect unemployment insurance, choose to consume their current income.unemployment fluctuations, sunspots equilibria, expected inflation, wage bargaining

Tax Rate Variability and Public Spending as Sources of Indeterminacy

We consider a constant returns to scale, one sector economy with segmented asset markets of the Woodford (1986) type. We analyze the role of public spending, financed by labor income and consumption taxation, on the emergence of indeterminacy. We find that what is relevant for indeterminacy is the variability of the distortion introduced by government intervention. We further discuss the results in terms of the level of the tax rate, its variability with respect to the tax base and the degree of externalities in preferences due to the existence of a public good. We show that the degree of public spending externalities affects the combinations between the tax rate and its variability under which indeterminacy occurs. Moreover, in contrast to previous results, we find that consumption taxes can lead to local indeterminacy when asset markets are segmented.Indeterminacy ; public spending ; taxation ; segmented asset markets

Market Distortions and Local Indeterminacy: A General Approach

We provide a methodology to study the role of market distortions on the emergence of indeterminacy and bifurcations. Most of the specific market imperfections considered in the related literature are particular cases of our framework. Comparing them we obtain several equivalence results in terms of local dynamic properties, highlighting the main channels and classes of distortions responsible for indeterminacy. Our methodology consists in introducing general specifications for the elasticities of the crucial functions defining the aggregate equilibrium dynamics of the model. This allows us to study how market distortions influence the range of values for the elasticity of inputs substitution under which local indeterminacy and bifurcations occur. Applying this methodology to the Woodford (1986) framework we find that distortions in the capital market, per se, do not play a major role. We further show that, for empirically plausible values of elasticity of substitution between inputs, indeterminacy requires a minimal degree of distortions. This degree seems to be high under output market distortions, while with labor market distortions the required degree is empirically plausible.externalities, market imperfections, endogenous fluctuations, indeterminacy, imperfect competition, taxation

Market distortions and local indeterminacy: a general approach

We provide a methodology to study the role of market distortions on the emergence of indeterminacy and bifurcations. Most of the specific market imperfections considered in the related literature are particular cases of our framework. Comparing them we obtain several equivalence results in terms of local dynamic properties, highlighting the main chanels and classes of distortions responsible for indeterminacy. Our methodolgy consists in introducing general specifications for the elasticities of the crucial functions defining the aggregate equilibrium dynamics of the model. This allows us to study how market distortions influence the range of values for the elasticity of inputs substitution under which local indeterminacy and bifurcations occur. Applying this methodology to the Woodford (1986) framework we find that distortions in the capital market, per se, do not play a major role. We further show that, for empirically plausible values of elasticity of substitution between inputs, indeterminacy requires a minimal degree of distortions. This degree seems to be high under output market distortions, while with labor market distortions the required degree is empirically plausible.Indeterminacy; endogenous fluctuations; market imperfections; externalities; imperfect competition; taxation

Unionized Labor Markets and Globalized Capital Markets

This paper studies the effects of international integration of capital markets in a world where countries differ in their labor market institutions: one country has a perfectly competitive labor market while the other is unionized. We show that workers should favor autarky in the unionized country, but oppose it in the non unionized country and vice versa for owners of capital. Aggregate gains from integration, however, are negative. We also show that, under capital mobility, an increase in relative bargaining power of unions does not always improve workers’ welfare.Capital mobility, Globalization, Unions, Welfare.

Endogenous Business Cycles and Stabilization Policies

We analyze the effects of simple stylized economic policy rules, or stabilization principles, when fluctuations in economic activity are created endogenously by self_fulfilling volatile expectations. We study a simple monetary competitive model with intertemporally optimizing agents and a government. We only depart from neoclassical orthodoxy by assuming that a cycle or a sunspot equilibrium, not necessarily a steady state, could be the descriptive dynamic rational expectations equilibrium. The government may then well out of welfare concerns want to conduct systematic stabilization policy through transfers, expenditure, and taxation even though this has distortionary effects. We show that the policy rules that stabilize output in a way that is best for welfare involve countercyclical elements in government activity.Endogenous business cycles; Stabilization policy

Unions and Globalisation

We analyze the effects of international integration of product and capital markets (i.e., globalisation) in a world where countries differ in their labour market institutions: one country has a perfectly competitive labour market while the other is unionized. We show that workers should favour autarky in the unionized country, but oppose it in the non unionized country. Vice versa for owners of capital. Aggregate gains from integration, however, are negative. We also show that, under capital mobility an increase in relative bargaining power of unions does not always improve workers' welfare: there is a critical level of bargaining strength above which an increase in union power reduces workers' income in the unionized country.Capital mobility, Unions, Globalisation

Endogenous business cycles and stabilization policies

The paper reports results on the effects of stylized stabilization policies on endogenously created fluctuations. A simple monetary model with intertemporally optimizing agents is considered. Fluctuations in output may occur due to fluctuations in labor supply which are again caused by volatile expectations which are ``self fulfilling'', i.e. correct given the model. It turns out that stabilization policies that are sufficiently countercyclical in the sense that government spending (on transfers or demand) depends sufficiently strongly negatively on GNP-increases can stabilize the economy at a monetary steady state for an arbitrarily low degree of distortion of that steady state. Such stabilization has unambiguously good welfare effects and can be achieved without features such as positive lump sum taxation or negative income taxation as part of the stabilization policy.Endogenous business cycles, stabilization policy