11,697 research outputs found
Avoided Critical Behavior in a Uniformly Frustrated System
We study the effects of weak long-ranged antiferromagnetic interactions of
strength 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 is strictly greater
than . The behavior of this system at temperatures less
than 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
THE EFFECT OF CMV INFECTION ON PROGRESSION OF HUMAN-IMMUNODEFICIENCY-VIRUS DISEASE IN A COHORT OF HEMOPHILIC MEN FOLLOWED FOR UP TO 13 YEARS FROM SEROCONVERSION
The effect of prior infection with cytomegalovirus (CMV) on progression of HIV disease in a cohort of 111 men with haemophilia was studied after 13 years followup. The relative hazards associated with CMV positivity on progression to AIDS, death and a CD4 count of 0.05 x 10(9)/l were 2.28, 2.42 and 2.34, respectively. CMV seropositive patients were significantly older than the seronegative and this was controlled for by using a Cox proportional hazards model. The relative hazards for the three endpoints decreased to 1.89, 1.82 and 1.93 respectively and were marginally non-significant (P = 0.05, 0.08 and 0.08 for the three endpoints respectively). We conclude that this cohort continues to show evidence of a 'co-factor' effect associated with prior infection with CMV which is confounded by age but not completely explained by age differences. The potential biological significance of these results is discussed in the context of recent controlled clinical trials which show a survival benefit from long-term high-dose acyclovir, a drug with activity in vivo against CMV and other herpesviruses
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
Symposium on the Seventy-Fifth Anniversary of \u3ci\u3eVillage of Euclid v. Ambler Realty Co.\u3c/i\u3eIntroduction
- …