What should economists measure? The implications of mass production vs. mass customization

Consumer behavior ; Production (Economic theory) ; Productivity

Country-bashing tariffs: do bilateral trade deficits matter?

Balance of trade ; Tariff

Variety, globalization, and social efficiency

This paper puts recent work on the benefits of variety into the context of an exact quantitative analysis of the Dixit-Stiglitz-Krugman model of monopolistic competition. We show that the gains from international trade are almost completely determined by the increase in variety and not economies of scale, and that the social efficiency question is quantitatively insignificant. These results follow from allowing the number of varieties to affect the elasticity of demand facing each firm. Most applications of the DSK model abstract from variety’s effect by assuming that the elasticity of demand facing each firm equals the elasticity of substitution in a CES utility function, thus fixing the output of each firm by the resulting markup over marginal costs. Finally, we develop a precise expression for real per capita income with any number of sectors. ; Also issued as Globalization and Monetary Policy Institute Working Paper No. 15

Nonlinear Propagation of Light in One Dimensional Periodic Structures

We consider the nonlinear propagation of light in an optical fiber waveguide as modeled by the anharmonic Maxwell-Lorentz equations (AMLE). The waveguide is assumed to have an index of refraction which varies periodically along its length. The wavelength of light is selected to be in resonance with the periodic structure (Bragg resonance). The AMLE system considered incorporates the effects non-instantaneous response of the medium to the electromagnetic field (chromatic or material dispersion), the periodic structure (photonic band dispersion) and nonlinearity. We present a detailed discussion of the role of these effects individually and in concert. We derive the nonlinear coupled mode equations (NLCME) which govern the envelope of the coupled backward and forward components of the electromagnetic field. We prove the validity of the NLCME description and give explicit estimates for the deviation of the approximation given by NLCME from the {\it exact} dynamics, governed by AMLE. NLCME is known to have gap soliton states. A consequence of our results is the existence of very long-lived {\it gap soliton} states of AMLE. We present numerical simulations which validate as well as illustrate the limits of the theory. Finally, we verify that the assumptions of our model apply to the parameter regimes explored in recent physical experiments in which gap solitons were observed.Comment: To appear in The Journal of Nonlinear Science; 55 pages, 13 figure

Studies on Nucleic Acid Reassociation Kinetics: Retarded Rate of Hybridization of RNA with Excess DNA

The rate of reaction of excess double-stranded bacteriophage phi X174 and plasmid RSF2124 DNA drivers with enzymatically synthesized asymmetric RNA tracers was measured. Other reactions were carried out with excess Escherichia coli DNA and E. coli RNA labeled in vivo. RNA and DNA fragment lengths were held approximately equal. For each case it was shown that in DNA excess the rate constant for RNA· DNA hybridization is 3- to 4.5-fold lower than that of the renaturation rate constant for the driver DNA. This retardation was also observed in pseudo-first-order hybridization reactions driven by excess strand-separated RSF2124 DNA. It was concluded that the rate constant for RNA· DNA hybridization depends partially on which species is in excess