On the dynamics created by a time--dependent Aharonov-Bohm flux

We study the dynamics of classical and quantum particles moving in a punctured plane under the influence of a homogeneous magnetic field and driven by a time-dependent singular flux tube through the hole

All Americans at Risk of Receiving Poor Quality Health Care

Summarizes a study of the health care Americans receive compared to the health care they should receive and of the links between the quality of care received and patient characteristics, including age, gender, race/ethnicity, income, and insurance status

Fractal Weyl Law for Open Chaotic Maps

This contribution summarizes our work with M.Zworski on open quantum open chaoticmaps (math-ph/0505034). For a simple chaotic scattering system (the open quantum baker's map), we compute the "long-living resonances" in the semiclassical r\'{e}gime, and show that they satisfy a fractal Weyl law. We can prove this fractal law in the case of a modified model.Comment: Contribution to the Proceedings of the conference QMath9, Mathematical Physics of Quantum Mechanics, September 12th-16th 2004, Giens, Franc

Quantum Transport on KAM Tori

Although quantum tunneling between phase space tori occurs, it is suppressed in the semiclassical limit $\hbar\searrow 0$ for the Schr\"{o}dinger equation of a particle in \bR^d under the influence of a smooth periodic potential. In particular this implies that the distribution of quantum group velocities near energy $E$ converges to the distribution of the classical asymptotic velocities near $E$, up to a term of the order \cO(1/\sqrt{E}).Comment: 21 page

Collaborative Models Improve Some Aspects of Quality for Patients With Chronic Heart Failure

Summarizes a study of how collaborative interventions in which healthcare providers share lessons learned affect the quality of care for chronic heart failure patients. Compares patient education, counseling, and quality indicators as well as treatments

Dynamics of a classical Hall system driven by a time-dependent Aharonov--Bohm flux

We study the dynamics of a classical particle moving in a punctured plane under the influence of a strong homogeneous magnetic field, an electrical background, and driven by a time-dependent singular flux tube through the hole. We exhibit a striking classical (de)localization effect: in the far past the trajectories are spirals around a bound center; the particle moves inward towards the flux tube loosing kinetic energy. After hitting the puncture it becomes ``conducting'': the motion is a cycloid around a center whose drift is outgoing, orthogonal to the electric field, diffusive, and without energy loss

Predicting the Effectiveness of Self-Training: Application to Sentiment Classification

The goal of this paper is to investigate the connection between the performance gain that can be obtained by selftraining and the similarity between the corpora used in this approach. Self-training is a semi-supervised technique designed to increase the performance of machine learning algorithms by automatically classifying instances of a task and adding these as additional training material to the same classifier. In the context of language processing tasks, this training material is mostly an (annotated) corpus. Unfortunately self-training does not always lead to a performance increase and whether it will is largely unpredictable. We show that the similarity between corpora can be used to identify those setups for which self-training can be beneficial. We consider this research as a step in the process of developing a classifier that is able to adapt itself to each new test corpus that it is presented with

Monopsony and Labor Supply in the Army and Navy

Because it is differentiated from other employers, the U.S. military enjoys some monopsony power. After reviewing existing estimates of the elasticity of labor supplied to the military, we obtain new estimates for the Army and Navy covering the period from 1998-2007. We employ a control function approach to account for the potential endogeneity of enlistment incentives. Our elasticity estimates of 2.4 for the Army and .4 for the Navy suggest that the services have substantial wage-setting ability. However, the Army faces higher supply elasticity since the invasion of Iraq and higher elasticity in states with weak support for obligatory military service.military, labor supply, monopsony papers

Resonant cyclotron acceleration of particles by a time periodic singular flux tube

We study the dynamics of a classical nonrelativistic charged particle moving on a punctured plane under the influence of a homogeneous magnetic field and driven by a periodically time-dependent singular flux tube through the hole. We observe an effect of resonance of the flux and cyclotron frequencies. The particle is accelerated to arbitrarily high energies even by a flux of small field strength which is not necessarily encircled by the cyclotron orbit; the cyclotron orbits blow up and the particle oscillates between the hole and infinity. We support this observation by an analytic study of an approximation for small amplitudes of the flux which is obtained with the aid of averaging methods. This way we derive asymptotic formulas that are afterwards shown to represent a good description of the accelerated motion even for fluxes which are not necessarily small. More precisely, we argue that the leading asymptotic terms may be regarded as approximate solutions of the original system in the asymptotic domain as the time tends to infinity