On the non-perturbative realization of QCD gauge-invariance

A few years ago the use of standard functional manipulations was demonstrated to imply an unexpected property satisfied by the fermionic Green's functions of QCD: effective locality. This feature of QCD is non-perturbative as it results from a full integration of the gluonic degrees of freedom. In this paper, previous derivations of effective locality are reviewed, corrected, and enhanced. Focussing on the way non-abelian gauge invariance is realized in the non-perturbative regime of QCD, the deeper meaning of effective locality is discussed.Comment: 18 page

Auto-titrating continuous positive airway pressure for patients with acute transient ischemic attack: a randomized feasibility trial

BACKGROUND AND PURPOSE: Transient ischemic attack (TIA) patients are at risk of recurrent vascular events. The primary objectives were to evaluate among TIA patients the prevalence of sleep apnea and among patients with sleep apnea auto-titrating continuous positive airway pressure (auto-CPAP) adherence. The secondary objective was to describe among TIA patients with sleep apnea the recurrent vascular event rate by auto-CPAP use category. METHODS: All intervention patients received auto-CPAP for 2 nights, but only intervention patients with evidence of sleep apnea received auto-CPAP for the remainder of the 90-day period. Intervention patients received polysomnography at 90 days after TIA. Control patients received polysomnography at baseline and at 90 days. Acceptable auto-CPAP adherence was defined as >or=4 hours per night for >or=75% of nights. Vascular events included recurrent TIA, stroke, hospitalization for congestive heart failure, myocardial infarction, or death. RESULTS: We enrolled 70 acute TIA patients: 45 intervention and 25 control. The majority of patients had sleep apnea: 57% at baseline and 59% at 90 days. Among the 30 intervention patients with airflow obstruction, 12 (40%) had acceptable auto-CPAP adherence, 18 (60%) had some use, and none had no use. Three intervention patients (12%) had recurrent events compared with 1 (2%;P=0.13) control patient. The vascular event rate was highest among sleep apnea patients with no CPAP use: none, 16%;some, 5%;acceptable adherence 0% (P=0.08). CONCLUSIONS: Sleep apnea is common among acute TIA patients. It appears feasible to provide auto-CPAP in the acute TIA period. Larger studies should evaluate whether a strategy of diagnosing and treating sleep apnea can reduce recurrent vascular events after TIA

Treating frailty-a practical guide

Frailty is a common syndrome that is associated with vulnerability to poor health outcomes. Frail older people have increased risk of morbidity, institutionalization and death, resulting in burden to individuals, their families, health care services and society. Assessment and treatment of the frail individual provide many challenges to clinicians working with older people. Despite frailty being increasingly recognized in the literature, there is a paucity of direct evidence to guide interventions to reduce frailty. In this paper we review methods for identification of frailty in the clinical setting, propose a model for assessment of the frail older person and summarize the current best evidence for treating the frail older person. We provide an evidence-based framework that can be used to guide the diagnosis, assessment and treatment of frail older people

Modern functional quantum field theory: summing Feynman graphs

A monograph, which can also be used as a textbook for graduate students, this book contains new and novel applications of Schwinger's well-known functional solutions, made possible by the use of Fradkin's little-known functional representations, together with recent research work of the author and his colleagues

QCD Effective Locality: A Theoretical and Phenomenological Review

About ten years ago, the use of standard functional manipulations was demonstrated to imply an unexpected property satisfied by the fermionic Green’s functions of QCD and dubbed Effective Locality. This feature of QCD is non-perturbative, as it results from a full gauge invariant integration of the gluonic degrees of freedom. In this review article, a few salient theoretical aspects and phenomenological applications of this property are summarized

Research program in theoretical high-energy physics. Progress report. [Summaries of research activities at Brown Univ]

Last year's research program dealt with a large range of topics in high energy theoretical physics. Included in the problems studied were: flavor mixing angles in flavor gauge theory; grand unification schemes; neutral current phenomenology; charmonium decays; perturbative aspects of soft hadronic phenomena within the framework of the dual topological expansion; Regge trajectory slopes and the shape of the inclusive spectra; bound states in quantum electrodynamics; calculations of the Lamb Shift and hyperfine splitting in hydrogen (and muonium) through order ..cap alpha..(Z..cap alpha..)/sup 6/; perturbation theory resummation techniques; collective behavior of instantons in quantum chromodynamics; 1/N expansion and mean field expansion techniques (applied to the nonlinear sigma model, classical solutions to Yang-Mills theories, and renormalized four-Fermi models of weak interactions); semiclassical calculation of Z/sub 1/(..cap alpha..) in scalar QED; group theoretic studies of spontaneous symmetry breaking; fibre bundles applied to the topological aspects of gauge theories; strong-coupling expansions (as an aspect of infrared behavior, as a systematic perturbation expansion with reference to lattice extrapolation, applied to classical statistical mechanics, applied to problems with nonquadratic kinetic energy terms, and in transfer matrix formulations); eikonal methods (three-body Coulomb scattering, quark-antiquark potentials); computer augmented solutions to quantum field theory; topological excitations in two-dimensional models and WKB approximation on a lattice. A list of publications is included

QCD Effective Locality: A Theoretical and Phenomenological Review

About ten years ago, the use of standard functional manipulations was demonstrated to imply an unexpected property satisfied by the fermionic Green’s functions of QCD and dubbed Effective Locality. This feature of QCD is non-perturbative, as it results from a full gauge invariant integration of the gluonic degrees of freedom. In this review article, a few salient theoretical aspects and phenomenological applications of this property are summarized