This paper proposes a general empirical measure of the degree of product differentiation between two products. The robustness of this measure is tested using a rich new panel data set on filmprogramming choice in a major U.S. metropolitan motion-pictures exhibition market. The degree of similarity between two products is captured by the extent to which the two products share the same attributes...

Amartya Sen has correctly sought to correct some shortcomings within neoclassical economic theory. Nonetheless, there still exists a tension in his work. His overall frame of analysis is still congruent with much of the neoclassical tradition. However, his critiques seem to imply that a sharp break with neoclassical theory is necessary. This conflict is examined in light of the connections betw...

In this letter we present a dynamical study of the structure of metastable states (corresponding to TAP solutions) in a mean-field spin–glass model. After reviewing known results of the statical approach, we use dynamics: starting from an initial condition thermalized at a temperature between the statical and the dynamical transition temperatures, we are able to study the relaxational dynamics ...

More than 1300 variables classified provisionally as first overtone RR Lyrae pulsators in the macho variable star database of the Large Magellanic Cloud (LMC) have been subjected to standard frequency analysis. Based on the remnant power in the prewhitened spectra, we found 70% of the total population to be monoperiodic. The remaining 30% (411 stars) are classified as one of 9 types according t...

We study two types of axially symmetric, stationary and asymptotically flat spacetimes using highly accurate numerical methods. One type contains a black hole surrounded by a perfect fluid ring and the other a rigidly rotating disc of dust surrounded by such a ring. Both types of spacetime are regular everywhere (outside of the horizon in the case of the black hole) and fulfil the requirements ...

The final assembly of terrestrial planets occurs via massive collisions, which can launch copious clouds of dust that are warmed by the star and glow in the infrared. We report the real-time detection of a debris-producing impact in the terrestrial planet zone around a 35-million year-old solar analog star. We observed a substantial brightening of the debris disk at 3-5 μm, followed by a decay ...