Avoided Critical Behavior in a Uniformly Frustrated System

We study the effects of weak long-ranged antiferromagnetic interactions of strength $Q$ on a spin model with predominant short-ranged ferromagnetic interactions. In three dimensions, this model exhibits an avoided critical point in the sense that the critical temperature $T_c(Q=0)$ is strictly greater than $\lim_{Q\to 0} T_c(Q)$. The behavior of this system at temperatures less than $T_c(Q=0)$ is controlled by the proximity to the avoided critical point. We also quantize the model in a novel way to study the interplay between charge-density wave and superconducting order.Comment: 32 page Latex file, figures available from authors by reques

Salem numbers and arithmetic hyperbolic groups

In this paper we prove that there is a direct relationship between Salem numbers and translation lengths of hyperbolic elements of arithmetic hyperbolic groups that are determined by a quadratic form over a totally real number field. As an application we determine a sharp lower bound for the length of a closed geodesic in a noncompact arithmetic hyperbolic n-orbifold for each dimension n. We also discuss a "short geodesic conjecture", and prove its equivalence with "Lehmer's conjecture" for Salem numbers.Comment: The exposition in version 3 is more compact; this shortens the paper: 26 pages now instead of 37. A discussion on Lehmer's problem has been added in Section 1.2. Final version, to appear is Trans. AM

Evolution of Magnetic and Superconducting Fluctuations with Doping of High-Tc Superconductors (An electronic Raman scattering study)

For YBa_2Cu_3O_{6+\delta} and Bi_2Sr_2CaCu_2O_8 superconductors, electronic Raman scattering from high- and low-energy excitations has been studied in relation to the hole doping level, temperature, and energy of the incident photons. For underdoped superconductors, it is concluded that short range antiferromagnetic (AF) correlations persist with hole doping and doped single holes are incoherent in the AF environment. Above the superconducting (SC) transition temperature T_c the system exhibits a sharp Raman resonance of B_1g symmetry and about 75 meV energy and a pseudogap for electron-hole excitations below 75 meV, a manifestation of a partially coherent state forming from doped incoherent quasi-particles. The occupancy of the coherent state increases with cooling until phase ordering at T_c produces a global SC state.Comment: 5 pages, 4 EPS figures; SNS'97 Proceedings to appear in J. Phys. Chem. Solid

Landau theory of phase separation in cuprates

I discuss the problem of phase separation in cuprates from the point of view of the Landau theory of Fermi liquids. I calculate the rate of growth of unstable regions for the hydrodymanics and collisionless limit and, in presence of long range Coulomb interactions, the size of these regions. These are analytic results valid for any strength of the Landau parameters.Comment: RevteX, preprint ITP (1994

Food Habits of the Western Painted Turtle, Chrysemys marginata bellii Gray

This investigation summarizes an attempt to obtain conclusive evidence as to food habits of one of our very common turtles, Chrysemys marginata bellii (Gray). In the literature of the food habits of turtles little data is recorded in regard to Chrysemys marginata bellii, although there is much scattered information concerning other species of this genus. The food habits of many of our turtles on the other hand have been briefly reveiwed by Ditmars (1), Babcock (2), Morgan (3), Ruthven (4), and Surface (5). Surface has studied the food habits of several species of turtles and his data seem to be the most complete. Pope (6) has recently reviewed most of the available data on food and food habits of turtles in his interesting popular treatise: Turtles of the United States and Canada

Sustaining the Medical Home: How PROMETHEUS Payment Can Revitalize Primary Care

Argues for reforming the current fee-for-service payment system on the PROMETHEUS model of budgeting for a comprehensive episode of care for a condition. Analyzes the implications for a sustainable patient-centered medical home model of care delivery

Law Without Lawyers: Access to Civil Justice and the Cost of Legal Services

The high cost of legal services presents a significant access-to-justice problem. In this Article, I argue that this problem is actually two distinct problems—one affecting primarily low- and moderate income persons, and one affecting primarily deep-pocketed corporate defendants. Because the problems are different, they are probably not amenable to a single solution. Most significantly, the Article applies Baumol’s “cost disease” to the rising cost of legal services, thus placing the debate over rising legal costs in a wider economic contex

Law Without Lawyers: Access to Civil Justice and the Cost of Legal Services

The high cost of legal services presents a significant access-to-justice problem. In this Article, I argue that this problem is actually two distinct problems—one affecting primarily low- and moderate income persons, and one affecting primarily deep-pocketed corporate defendants. Because the problems are different, they are probably not amenable to a single solution. Most significantly, the Article applies Baumol’s “cost disease” to the rising cost of legal services, thus placing the debate over rising legal costs in a wider economic contex