12,719 research outputs found
Quantum lattice models at intermediate temperatures
We analyze the free energy and construct the Gibbs-KMS states for a class of
quantum lattice systems, at low temperatures and when the interactions are
almost diagonal in a suitable basis. We study systems with continuous symmetry,
but our results are valid for discrete symmetry breaking only. Such phase
transitions occur at intermediate temperatures where the continuous symmetry is
not broken, while at very low temperature continuous symmetry breaking may
occur.Comment: 25 pages, 6 figure
EDUCATIONAL PERFORMANCE AND SPATIAL CONVERGENCE IN PERU
While an enormous and growing literature exists on the topic of re-gional income convergence, other aspects of socioeconomic well-being and development have attracted much less attention. Social indicators are a valuable complement to economic indicators when analyzing spatial patterns in a given geographic region, and can often yield a more comprehensive view about re-gional socioeconomic behavior. In poorer nations dominated by many low in-come areas that exhibit similar economic performance, social indicators may reveal further insight into the differences among regions. This paper explores the issue of educational convergence in Peru over the period 1993 to 2005. Using both exploratory spatial data analysis and spatial econometrics, the study is conducted at province level in order to uncover potential spatial patterns that help explain variation in educational performance over time, among regions, and across different terrain.SPATIAL CONVERGENCE, EDUCATION, PERU
"Aggregation Bias" DOES explain the PPP puzzle
This article summarizes our views on the role of an "aggregation bias" in explaining the PPP Puzzle, in response to the several papers recently written in reaction to our initial contribution. We discuss in particular the criticisms of Imbs, Mumtaz, Ravn and Rey (2002) presented in Chen and Engel (2005). We show that their contentions are based on: (i) analytical counter-examples which are not empirically relevant; (ii) simulation results minimizing the extent of "aggregation bias"; (iii) unfounded claims on the impact of measurement errors on our results; and (iv) problematic implementation of small-sample bias corrections. We conclude, as in our original paper, that "aggregation bias" goes a long way towards explaining the PPP puzzle
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