As the exchange rate, foreign demand, production costs and export promotion policies evolve, manufacturing firms are continually faced with two issues: Whether to be an exporter, and if so, how much to export. We develop a dynamic structural model of export supply that characterizes these two decisions and estimate the model using plant-level panel data on Colombian chemical producers. The model embodies uncertainty, plant-level heterogeneity in export profits, and sunk entry costs for plants breaking into foreign markets. Our estimates, and the simulation exercises that they support, yield several implications. First, entry costs are typically large, but vary greatly across producers. Second, there is substantial cross-plant heterogeneity in gross expected export profit streams. Third, these large entry costs make expectations about future exporting conditions important for many producers, so changes in the exchange rate regime that are credible induce much more entry than those that are not. Fourth, however, most of the entry and exit takes place among marginal exporters who contribute little to aggregate export revenues. Finally, subsidies on export earnings have a much larger impact on export revenues (per dollar spent) than subsidies that reduce the entry costs faced by new exporters. (Baldwin and Krugman, 1989;Dixit, 1989;Krugman, 1989 These features of the Colombian chemical industry shape the results of our policy simulations. First, the fact that sunk entry costs are large makes expectations about future exporting conditions important for many plants. Thus we find that a moderate shift in the mean of the log exchange rate process induces sustained net entry by new exporters and rising export volumes if producers view it as a credible regime shift. On the other hand, the exact same change in the exchange rate process induces far less entry when producers retain their old beliefs about 2 Earlier studies of export market participation have focused on the null hypothesis that sunk costs don't matter, but have not been structural and thus have not quantified sunk costs (Roberts and Tybout, 1997a;Campa, 1998;Bernard and Jensen, 2001;Bernard and Wagner, 2001).3 the exchange rate process.Second, profits for the major exporters are sufficiently large to keep them in the export market under any reasonable policy scenario. So the foreign market entry and exit that takes place is concentrated among small suppliers who have a relatively minor effect on export volumes. It follows that, while expectations have a dramatic effect on the number of exporters, their effect on the volume of exports is much more modest.Third, policies that promote exports through per-unit subsidies generate far larger responses per peso spent than policies that promote exports through lump-sum transfers for new exporters. The reasons are that (1) exporters that need a subsidy to get into export markets are almost always marginal suppliers; (2) these same exporters face relatively high entry costs, and (3) large incumbent exporters, ...

The state-specific multireference coupled-cluster (SS-MRCC) ansatz developed by Mukherjee and co-workers [J. Chem. Phys. 110, 6171 (1999)] has been implemented by means of string-based techniques. The implementation is general and allows for using arbitrary complete active spaces of any spin multiplicity and arbitrarily high excitations in the cluster operators. Several test calculations have been performed for single- and multiple-bond dissociations of molecular systems. Our experience shows that convergence problems are encountered when solving the working equations of the SS-MRCC in the case the weight of one or more reference functions tends to take on very small values. This is system specific and cannot yet be handled in a black-box fashion. The problem can be obviated by either dropping all the cluster amplitudes from the corresponding model functions with coefficients below a threshold or by a regularization procedure suggested by Tikhonov or a combination of both. In the current formulation the SS-MRCC is not invariant with respect to transformation of active orbitals among themselves. This feature has been extensively explored to test the degree of accuracy of the computed energies with both pseudocanonical and localized active orbitals. The performance of the method is assessed by comparing the results with the corresponding full configuration interaction (CI) values with the same set of orbitals (correlated and frozen). Relative efficacies of CI methods such as MRCI singles and doubles with the same active space and size-extensivity corrected ones such as MR averaged coupled pair functional and MR averaged quadratic CC have also been studied. Allied full-fledged CC methods have also been employed to see their relative performance vis-à-vis the SS-MRCC. These latter methods are the complete-active-space-inspired single-reference (SR) CC based SS theory and the single-root MR Brillouin-Wigner CC. Our benchmark results indicate that the performance of the SS-MRCC is generally quite good for localized active orbitals. The performance with the pseudocanonical orbitals, however, is sometimes not as satisfactory as for the localized orbitals.

High-precision quantum chemical calculations have been performed for atmospherically important halomethane derivatives including CF, CF(3), CHF(2), CH(2)F, CF(2), CF(4), CHF, CHF(3), CH(3)F, CH(2)F(2), CCl, CCl(3), CHCl(2), CH(2)Cl, CCl(2), CCl(4), CHCl, CHCl(3), CH(3)Cl, CH(2)Cl(2), CHFCl, CF(2)Cl, CFCl(2), CFCl, CFCl(3), CF(2)Cl(2), CF(3)Cl, CHFCl(2), CHF(2)Cl, and CH(2)FCl. Theoretical estimates for the standard enthalpy of formation at 0 and 298.15 K as well as for the entropy at 298.15 K are presented. The determined values are mostly within the experimental uncertainty where accurate experimental results are available, while for the majority of the considered heat of formation and entropy values the present results represent the best available estimates.

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We investigate determinants of household firewood collection in rural Nepal, using 1995-96 and 2002-3 World Bank Living Standards Measurement Survey (LSMS) data. We incorporate village fixed effects, endogenous censoring, measurement error in living standards and heterogeneous effects of different household assets. We find no evidence in favor of the poverty-environment hypothesis. The evidence for the environmental Kuznets curve depends on the precise measure of living standards and time period studied. Firewood collections fall with a transition to modern occupations and rise with increasing population and household division. The local interhousehold collection externality is negligible, indicating that policy interventions are justified only by ecological considerations or nonlocal spillovers.

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Some studies on child labor have shown that, at the level of the household, greater land wealth leads to higher child labor, thereby casting doubt on the hypothesis that child labor is caused by poverty. This paper argues that the missing ingredient may be an explicit modeling of the labor market. We develop a simple model which suggests the possibility of an inverted-U relationship between land holdings and child labor. Using a unique data set that has child labor hours it is found that, controlling for child, household and village characteristics, the turning point beyond which more land leads to a decline in child labor occurs around 4 acres of land per household.

As the exchange rate, foreign demand, and production costs evolve, domestic producers are continually faced with two choices: whether to be an exporter and, if so, how much to export. We develop a dynamic structural model of export supply that characterizes these two decisions. The model embodies plant-level heterogeneity in export profits, uncertainty about the determinants of future profits, and market entry costs for new exporters. Using a Bayesian Monte Carlo Markov chain estimator, we fit this model to plant-level panel data on three Colombian manufacturing industries. We obtain profit function and sunk entry cost coefficients, and use them to simulate export responses to shifts in the exchange-rate process and several types of export subsidies. In each case, the aggregate export response depends on entry costs, expectations about the exchange rate process, prior exporting experience, and producer heterogeneity. Export revenue subsidies are far more effective at stimulating exports than policies that subsidize entry costs. Copyright The Econometric Society 2007.