Dynamics of two interacting particles in classical billiards

The problem of two interacting particles moving in a d-dimensional billiard is considered here. A suitable coordinate transformation leads to the problem of a particle in an unconventional hyperbilliard. A dynamical map can be readily constructed for this general system, which greatly simplifies calculations. As a particular example, we consider two identical particles interacting through a screened Coulomb potential in a one-dimensional billiard. We find that the screening plays an important role in the dynamical behavior of the system and only in the limit of vanishing screening length can the particles be considered as bouncing balls. For more general screening and energy values, the system presents strong non-integrability with resonant islands of stability.Comment: REVTEX manuscript, 4 figures (1 ps + 3 gif, Postscript versions available upon request). Also available at http://www.phy.ohiou.edu/~ulloa/ulloa.htm

Microentrepreneurship and the business cycle: is self-employment a desired outcome?

Should a central bank accommodate energy price shocks? Should the central bank use core inflation or headline inflation with the volatile energy component in its Taylor rule? To answer these questions, we build a dynamic stochastic general equilibrium model with energy use, durable goods, and nominal rigidities to study the effects of an energy price shock and its impact on the macroeconomy when the central bank follows a Taylor rule. We then study how the economy performs under alternative parameterizations of the rule with different weights on headline and core inflation after an increase in the energy price. Our simulation results indicate that a central bank using core inflation in its Taylor rule does better than one using headline inflation because the output drop is less severe. In general, we show that the lower the weight on energy price inflation in the Taylor rule, the impact of an energy price increase on gross domestic product and inflation is also lower.

Who benefits from reducing the cost of formality? Quantile regression discontinuity analysis

This paper studies the effects of increasing formality via tax reduction and simplification schemes on micro-firm performance. It uses the 1997 Brazilian SIMPLES program. We develop a simple theoretical model to show that SIMPLES has an impact only on a segment of the micro-firm population, for which the effect of formality on firm performance can be identified, and that can be analyzed along the single dimensional quantiles of the conditional firm revenues. To estimate the effect of formality, we use an econometric approach that compares eligible and non-eligible firms, born before and after SIMPLES in a local interval about the introduction of SIMPLES. We use an estimator that combines both quantile regression and the regression discontinuity identification strategy. The empirical results corroborate the positive effect of formality on microfirms' performance and produce a clear characterization of who benefits from these programs

Can foreign lobbying enhance development ? The case of tourism in the Caribbean

There exist legal channels for informational lobbying of U.S. policymakers by foreign principals. Foreign governments and private sector principals frequently and intensively use this institutional channel to lobby on trade and tourism issues. The authors empirically study whether such lobbying effectively achieves its goal of trade promotion in the context of Caribbean tourism and it is the first paper to examine the potential for using foreign lobbying as a vehicle for development. They use panel data to explore and quantify the association between foreign lobbying by Caribbean principals and U.S. tourist arrivals to Caribbean destinations. A variety of sensitivity analyses support the finding of a strong association. The policy implications are obvious and potentially important for developing countries.Tourism and Ecotourism,Economic Theory&Research,Accommodation&Tourism Industry,Political Systems and Analysis,Politics and Government

Deregulation and environmental differentiation in the electric utility industry.

This paper analyzes how economic deregulation impacts firm strategies and environmental quality in the electric utility industry. We find evidence that the deregulation introduced to this historically staid industry has stimulated environmental differentiation. Differentiation is most likely to appear where its point of uniqueness is valued by customers, and we confirm this relationship in our sample. Specifically, utilities that served customers who exhibited higher levels of environmental sensitivity generated more green power. The tendency for firms to differentiate in this way is lessened if they are relatively more dependent on coal-fired generation or relatively more efficient. Thus, there is evidence that firms sort themselves into either differentiation or low-cost strategies as the competitive realities of a deregulated world unfold. Deregulation and the ensuing environmental differentiation illustrate how utilities exploited formerly unmet customer demand for green power. The result has been greater levels of renewable generation and, hence, a cleaner environment.Deregulation; Environmental differentiation; Electric utility; Renewable energy; Productive efficiency;

Releasing constraints to growth or pushing on a string ? the impact of credit, training, business associations, and taxes on the performance of Mexican micro-firms

The authors employ propensity score matching and a traditional control function approach to examine the impact of participation in various societal institutions on microfirm performance in Mexico. They find that firms that participate in credit markets, receive training,pay taxes, and belong to business associations exhibit significantly higher profits, even after controlling for the various factors that drive participation in those institutions. They also find that firms that borrow from formal or informal sources and those that pay taxes are significantly more likely to stay in business, but firms that received credit exhibit lower rates of income growth. Overall, the results suggest that even if the best performing micro-firms are more likely to be selected into participating in societal institutions, causality also runs in the opposite direction. In particular, increases in strictly or broadly defined formality have the potential for increasing profits and survival rates, and appear to bring micro-firms closer to their optimal sizes.Economic Theory&Research,Science Education,Scientific Research&Science Parks,Investment and Investment Climate,Educational Sciences

Does Formality Improve Micro-Firm Performance? Quasi-Experimental Evidence from the Brazilian SIMPLES Program

This paper employs regression discontinuity methods to identify the effect of formality on Brazilian micro-firm performance. The SIMPLES program introduced in November 1996 consolidated multiple taxes and social security contributions into a single payment and reduced taxes for eligible small firms. This provides a quasi-natural experiment that allows us to eliminate many of the endogeneity issues surrounding the impact of formality, measured across several dimensions, on firm performance. We find that SIMPLES had a significant effect on the proportion of firms that have a license to operate, are registered as a legal entity, pay taxes and make social security contributions. Moreover, newly created firms that opt for operating formally achieve higher levels of revenue and profits, employ more workers and are more capital intensive (only for those firms that have employees). The channel through which this occurs is not access to credit or contracts with larger firms. Rather, it appears that the lower cost of contracting labor leads to adopting production techniques that involve greater permanence and a larger paid labor force.micro-firms, self-employment, informality