Endogenous longevity, health and economic growth: a slow growth for a longer life?

We establish a theoretical set-up that is able to endogenously integrate growth and longevity. Our model captures three links between them: a longer life expectancy results in an increase in savings as well as an increase in the workforce, but health and growth compete for resources. We find that the key element is the response of longevity to an increase in health resources. Our model suggests that the first two links could be the most important in poor countries, which could explain their experience of simultaneous increases in growth and life expectancy. The reverse result may apply for developed countries.Government Spending

Can fundamentals explain cross-country correlations of asset returns?.

Previous studies show that existing correlations between national returns are higher than correlations between the national growth rates of fundamental variables. This paper examines the ability of intertemporal asset pricing models to explain cross-country correlations of national returns. We find that when capital markets are assumed to be fully integrated, a simple intertemporal general equilibrium model is able to explain the observed co-variability of domestic asset returns but generates too little variability in those returns. Results improve considerably if a less restrictive version is employed. In that setting, both domestic variability and cross-country co-variability of returns are consistent with capital market integration.Asset pricing models; Cross-country correlations;

Effect of superabsorbent polymers (SAP) on fresh state mortars with ground granulated blast-furnace slag (GGBS)

Although cementitious materials are the main construction materials and worldwide produced, there is still a major concern about their sustainability and durability, especially in terms of conserving resources, reducing wastes, and decreasing the environmental impacts of repair and replacement. In general, cementitious materials are very susceptible to cracking provoked by autogenous shrinkage due to their associated self-desiccation process. The problem is even more critical in concrete with blended cements, including Portland cement with ground granulated blast-furnace slag (GGBS). The current paper evaluates efficiency of superabsorbent polymers (SAP) as internal curing agents; shrinkage reduction in mortars with different levels of cement replacement by GGBS (0, 25, 50, and 75%) is presented. The study is focused on three types of SAPs with different water absorption/desorption capacities (SAP I: 10 g/g, SAP II: 25–30 g/g, and SAP III: 35 g/g in cement paste solution). Tests of consistency, density, air content of fresh mortar, setting times, and autogenous shrinkage are analysed. The results showed that mortars with SAP can significantly reduce autogenous shrinkage for any studied GGBS content in comparison with the reference mortar. The reduction of autogenous shrinkage by SAP may decrease the cracking susceptibility and hence increase the sustainability level of the material for more durable constructions

Decision Problems for Petri Nets with Names

We prove several decidability and undecidability results for nu-PN, an extension of P/T nets with pure name creation and name management. We give a simple proof of undecidability of reachability, by reducing reachability in nets with inhibitor arcs to it. Thus, the expressive power of nu-PN strictly surpasses that of P/T nets. We prove that nu-PN are Well Structured Transition Systems. In particular, we obtain decidability of coverability and termination, so that the expressive power of Turing machines is not reached. Moreover, they are strictly Well Structured, so that the boundedness problem is also decidable. We consider two properties, width-boundedness and depth-boundedness, that factorize boundedness. Width-boundedness has already been proven to be decidable. We prove here undecidability of depth-boundedness. Finally, we obtain Ackermann-hardness results for all our decidable decision problems.Comment: 20 pages, 7 figure

The Elasticity of Substitution in Demand for Non-Tradable Goods in Uruguay

This paper`s main goal is to estimate the elasticity of substitution of non-tradable goods, paying special attention to empirical problems related to time-varying parameters, missing regressors and model misspecification. To that end, the paper creates a database and estimates, via three alternative methods, quarterly series of consumption and prices of tradable and non-tradable goods for Uruguay for the period 1983-2002. The econometric estimations of the parameter of interest were performed with VEC models. These estimates give a long-run elasticity of substitution of %0. 46 in the principal model and %0. 71 and %0. 75 in the two alternative models. Parametric stability tests are performed on the principal model, and the predictive ability of the model is also tested. It is concluded that, not only is the parameter of interest stable over time, but the model also has good predictive properties, even when tested in a very demanding environment: the period following Uruguay`s change of exchange rate regime in mid-2002.