The finite-sample size of the BDS test for GARCH standardized residuals

This paper uses a multivariate response surface methodology to analyze the size distortion of the BDS test when applied to standardized residuals of rst-order GARCH processes. The results show that the asymptotic standard normal distribution is an unreliable approximation, even in large samples. On the other hand, a simple log-transformation of the squared standardized residuals seems to correct most of the size problems. Nonethe-less, the estimated response surfaces can provide not only a measure of the size distortion, but also more adequate critical values for the BDS test in small samples.

Comparative advantage, heterogeneous firms and variable mark-ups

We develop a model of comparative advantage with monopolistic competition, that incorporates heterogeneous firms and endogenous mark-ups. We analyse how these features vary across countries with different factor endowments, and across markets of different size. In this model we can obtain trade gains via two channels. First, when we open the economy, most productive firms start to export their product, then, they demand more producing factors and wages rises, thus, those firms that are less productive will be forced to stop to produce. Second channel is via endogenous mark-ups, when we open the economy, the competition gets ``tougher'', then, mark-ups falls, thus, those firms that are less productive will stop to produce. We also show that comparative advantage works as a ``third channel'' of trade gains, because, all trade gains results are magnified in comparative advantage industry of both countries. We also make a numerical exercise to see how endogenous variables of the model vary when trade costs fall.

Effects of trade policy on technology adoption and investment

This paper studies the consequences of trade policy for the adoption of new technologies. It develops a dynamic international trade model with two sectors. Workers in manufacturing decide if new technologies are used, capital owners then choose investment. We analyze three different arrangements: free trade, tariffs, and quotas. In the model economy, free trade as well as tariffs guarantee that the most productive technology available will be used. In contrasL under a quota the most productive technology available will not be used at all times. Further, in the latter case investment and the capital stock are smaller than in the former one. Finally, there exists parameter values for which the computed difference in GDP is a factor of thirty.

Environmental policy and growth when inputs are differentiated in pollution intensity

Environmental policy affects the distribution of market shares if intermediate goods are differentiated in their pollution intensity. When innovations are environment-friendly, a tax on emissions skews demand towards new goods which are the most productive. In this case, the tax has to increase along a balanced growth path to keep the market shares of goods of different vintages constant. Comparing balanced growth paths, we find that an increase in the burden of environmental taxation spurs innovation because it increases the market share of recent vintages. As a result the cost of environmental policy in terms of slower growth is weaker and may even be absent.