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The Environmental Kuznets Curve (EKC) hypothesis establishes the existence of an inverted U-shaped relationship between income and environmental deterioration. This paper studies the relationship between the energy mix and pollutant emissions and uses an environmental dynamic general equilibrium model to carry out a structural estimation of the EKC hypothesis. The model considers a three-input production function, including energy. Energy is a composite of fossil fuels and renewable energy sources. The flow of pollutant emissions depends on fossil fuels’ consumption, which accumulates in a pollution stock, resulting in a negative externality that adversely impacts aggregate productivity. Simulations of the model support the existence of a steady-state EKC relationship between Gross Domestic Product (GDP) and the stock of pollution, where the negative slope side of the curve is very flat. We find that (i) the EKC hypothesis is only fulfilled when the elasticity of substitution between fossil fuel and renewable energy is high enough; (ii) the higher the elasticity of the productivity to the stock of pollution, the lower the optimal stock of pollution as a function of output; and (iii) emissions efficiency has a positive impact on the environment in the short-run, but negative in the long-run.

A recent strategy carried out by the aircraft industry to reduce the total cost of the new generation fighters has consisted in the development of a single airframe with different technical and operational specifications. This strategy has been designed to reduce costs in the Research, Design and Development phase with the ultimate objective of reducing the final unit price per aircraft. This is the case of the F-35 Lightning II, where three versions, with significant differences among them, are produced simultaneously based on a single airframe. Whereas this strategy seems to be useful to cut down pre-production sunk costs, their effects on production costs remain to be studied. This paper shows that this strategy can imply larger costs in the production phase by reducing learning acquisition and hence, the total effect on the final unit price of the aircraft is indeterminate. Learning curves are estimated based on the flyaway cost for the latest three fighter aircraft models: The A/F-18E/F Super Hornet, the F-22A Raptor, and the F-35A Lightning II. We find that learning rates for the F-35A are significantly lower (an estimated learning rate of around 9%) than for the other two models (around 14%).

This paper studies the relationship between the energy mix and the environment using a theoretical framework in which two alternative energy sources are considered: fossil fuels (dirty energy) and renewable energy (clean energy). We find that a positive aggregate productivity shock increases energy consumption and emissions but reduces energy intensity and emissions per unit of output as renewable energy consumption increases, that is, carbon emissions are procyclical but emissions per unit of output are countercyclical. Second, an energy efficiency improvement provokes a “rebound effect” above 100% (the backfire effect), resulting in a rise of pollutant emissions by increasing energy use. Third, a technological improvement in emissions leads to a reduction in emissions per unit of fossil fuel, but also implies a slow-down in the adoption of renewable energy sources. Finally, we consider the case of a decentralized economy in which the government chooses an optimal specific tax on fossil fuel to maximize social welfare. We show that the “second-best” policy is highly effective in correcting the negative effects of the environmental externality and able to almost achive the centralized economy outcome.

Existing empirical evidence (Baumol, American Economic Review, 1986; Abramovitz, Journal of Economic History, 1986) has shown the importance of productivity growth in explaining production dynamics over time. Technological progress has been identifed as the key factor driving long-term productivity growth. The contribution of this paper is twofold. First, the paper extends previous studies (Färe et al., American Economic Review, 1994; Caselli and Coleman, American Economic Review, 2006; Hsieh and Klenow, American Economic Journal: Macroeconomics, 2010; Jones, Handbook of Macroeconomics, 2016) and quantifes the contribution of technological progress and technical efciency to productivity growth using non-parametric Data Envelopment Analysis (DEA) with a sample from both developed and developing countries. Second, the paper extends the sample period from 1980 to 2017 to study recent trends. The current study uses data from the Penn World Table (PWT 9.1, Feenstra et al., American Economic Review, 2015) for a sample of 92 countries

This paper proposes a Lanchester-type combat model to simulate battles in which one or two of the opposing sides cannot use all the forces simultaneously due to some physical restriction (i.e., topographic constraints, transforming the battlefield into a bottleneck). We show that this model, when the bottleneck restriction applies to both sides, leads to the Lanchester’s linear law for both aimed- and unaimed-fire, but the rate of change over time is a constant. The main characteristics of the bottleneck combat model are the following: (1) the topographic constraint makes the quality (fighting effectiveness) and size of the restriction the more relevant factors for the outcome of the battle, reducing the relative importance of quantity; (2) the bottleneck transforms the Lanchester’s square law into the linear law under direct-fire; and (3) if quality is similar among foes, the topographic bottleneck restriction is irrelevant for victory. The model is used to simulate the Battle of Thermopylae and shows that if the bottleneck restriction had persisted and was not removed, the Persian army would have been defeated.

The purpose of this paper is to explore the extent to which traditional economic policies can be oriented by sound practices. It is becoming widely accepted that sustainable economic growth (and not only economic growth) is the final target of economic policies, but some economic policies are applied just looking to the short-run without taking in account the long-run perspective. Our aim is to show how a sustainable economic policy-making would be possible, making compatible the stabilization of the economy in the short-run with a sustainable economic growth in the long-run. We confront the design of economic policies with the 17 goals of the 2030 Agenda. We argue that all sustainable development goals can be attained by the design and implementation of sustainable economic policies. Finally, to illustrate this point, we will conduct a simulation exercise to show under which combinations of demand policies technological shocks would promote a path of sustainable growth. Our results will provide a reference framework for a sustainable economic policy-making.

This article studies the implications of highly skilled labor international migration in a two-country dynamic stochastic general equilibrium model. The model considers three types of workers: Science, Technology, Engineering, or Mathematics (STEM) workers, non-STEM college educated workers, and non-college educated workers. Aggregate productivity in each economy is a function of innovations, which can be produced only by STEM workers. The model predicts (i) the existence of a wage premium of STEM workers relative to non-STEM college educated workers, (ii) the skill wage premium is higher in the destination country and increases with positive technological shocks, (iii) a reduction in migration costs increases output, wages, and total labor in the destination country, with opposite effects in the country of origin, and (iv) high skilled immigrants reduce skilled native labor and do not affect unskilled labor. Finally, a migration policy designed to attract STEM workers generates similar effects to a positive aggregate productivity shock.

Lanchester-type combat models have been widely used to study the outcome of battles and to carry on counterfactual experiments to analyze the consequence of commanders' decisions, tactics, concentration/dispersion of forces, quality-versus quantity, and so on. This paper uses a stochastic salvo combat model to study the Battle of Midway. The model is calibrated according to the historical outcome. The model is then simulated and used to study four alternative counterfactual scenarios: (i) all of the launched American attack aircraft reach the Japanese carriers, (ii) the Japanese have one additional carrier, (iii) the Japanese do not wait to launch their attack aircraft, and (iv) the American carriers are spotted earlier. Contrary to the common wisdom that the result of the battle was an \"incredible\" American victory, Monte Carlo simulations show that the probability of the Japanese winning was very low and actually close to zero. Even in the most favorable scenario for the Japanese, the Battle of Midway remains an American victory.

En este artículo analizamos los determinantes del crecimiento económico adoptando una perspectiva global, considerando una muestra extensa de países, tanto desarrollados como en vías de desarrollo. El crecimiento económico lo descomponemos en dos grupos de factores: acumulación de factores productivos (crecimiento extensivo) y progreso tecnológico (crecimiento intensivo). Contrariamente a los resultados obtenidos previamente por la literatura, la acumulación de capital físico ha tenido un papel destacado en los avances en la renta per cápita, tanto en países desarrollados como en vías de desarrollo, en las últimas décadas, mientras que la aportación de la productividad total de los factores ha sido más moderada. Por otra parte, también se analiza cómo ha evolucionado la distribución de la renta entre factores productivos.