193 research outputs found
Generation of a Complete Set of Supersymmetric Shape Invariant Potentials from an Euler Equation
In supersymmetric quantum mechanics, shape invariance is a sufficient
condition for solvability. We show that all conventional additive shape
invariant superpotentials that are independent of obey two partial
differential equations. One of these is equivalent to the one-dimensional Euler
equation expressing momentum conservation for inviscid fluid flow, and it is
closed by the other. We solve these equations, generate the set of all
conventional shape invariant superpotentials, and show that there are no others
in this category. We then develop an algorithm for generating all additive
shape invariant superpotentials including those that depend on
explicitly.Comment: 4 page
Exactly solvable models of supersymmetric quantum mechanics and connection to spectrum generating algebra
For nonrelativistic Hamiltonians which are shape invariant, analytic
expressions for the eigenvalues and eigenvectors can be derived using the well
known method of supersymmetric quantum mechanics. Most of these Hamiltonians
also possess spectrum generating algebras and are hence solvable by an
independent group theoretic method. In this paper, we demonstrate the
equivalence of the two methods of solution by developing an algebraic framework
for shape invariant Hamiltonians with a general change of parameters, which
involves nonlinear extensions of Lie algebras.Comment: 12 pages, 2 figure
A survey of internal and family medicine residents: Assessment of disability-specific education and knowledge.
BACKGROUND: The literature suggests that primary care physicians are inadequately educated in the care of people with disabilities. No study to date has evaluated whether internal medicine (IM) and family medicine (FM) residents have received disability-specific education or their level of comfort in caring for people with physical disabilities.
OBJECTIVES: To assess IM and FM residents\u27 receipt of disability-specific education during medical school and residency; to evaluate their self-reported comfort in managing secondary conditions associated with physical disabilities and in coordinating therapies and services for individuals with disabilities; to gauge their interest in receiving disability-specific education.
METHODS: An on-line survey distributed to residents at a convenience sample of ten academic IM and FM residency programs in the northeastern United States. Participants (n = 176) were asked about their socio-demographic and training-specific characteristics and their self-assessed ability to manage secondary conditions associated with physical disabilities and coordinate care and services for individuals with disabilities. Chi Square tests were used to compare participant characteristics and outcomes.
RESULTS: Few participants had received disability-specific education during medical school or residency (34.6% and 11.2%, respectively), and nearly all (96.0%) expressed interest in receiving more. Small minorities reported feeling comfortable managing common secondary conditions or in coordinating therapies and services for individuals with disabilities.
CONCLUSION: Although one-fifth of adult Americans have a disability, few of our participating IM and FM residents had received disability-specific education or felt comfortable managing the care of people living with disabilities. Our results indicate a need to develop and disseminate disability-specific curricula
Method for Generating Additive Shape Invariant Potentials from an Euler Equation
In the supersymmetric quantum mechanics formalism, the shape invariance
condition provides a sufficient constraint to make a quantum mechanical problem
solvable; i.e., we can determine its eigenvalues and eigenfunctions
algebraically. Since shape invariance relates superpotentials and their
derivatives at two different values of the parameter , it is a non-local
condition in the coordinate-parameter space. We transform the shape
invariance condition for additive shape invariant superpotentials into two
local partial differential equations. One of these equations is equivalent to
the one-dimensional Euler equation expressing momentum conservation for
inviscid fluid flow. The second equation provides the constraint that helps us
determine unique solutions. We solve these equations to generate the set of all
known -independent shape invariant superpotentials and show that there
are no others. We then develop an algorithm for generating additive shape
invariant superpotentials including those that depend on explicitly,
and derive a new -dependent superpotential by expanding a Scarf
superpotential.Comment: 1 figure, 4 tables, 18 page
Cost-effectiveness of catheter ablation versus medical therapy for the treatment of atrial fibrillation in the United Kingdom.
INTRODUCTION: Research evidence has shown that catheter ablation is a safe and superior treatment for atrial fibrillation (AF) compared to medical therapy, but real-world practice has been slow to adopt an early interventional approach. This study aims to determine the cost effectiveness of catheter ablation compared to medical therapy from the perspective of the United Kingdom. METHODS: A patient-level Markov health-state transition model was used to conduct a cost-utility analysis. The population included patients previously treated for AF with medical therapy, including those with heart failure (HF), simulated over a lifetime horizon. Data sources included published literature on utilization and cardiovascular event rates in real world patients, a systematic literature review and meta-analysis of randomized controlled trials for AF recurrence, and publicly available government data/reports on costs. RESULTS: Catheter ablation resulted in a favorable incremental cost-effectiveness ratio (ICER) of £8614 per additional quality adjusted life years (QALY) gained when compared to medical therapy. More patients in the medical therapy group failed rhythm control at any point compared to catheter ablation (72% vs. 24%) and at a faster rate (median time to treatment failure: 3.8 vs. 10 years). Additionally, catheter ablation was estimated to be more cost-effective in patients with AF and HF (ICER = £6438) and remained cost-effective over all tested time horizons (10, 15, and 20 years), with the ICER ranging from £9047-£15 737 per QALY gained. CONCLUSION: Catheter ablation is a cost-effective treatment for atrial fibrillation, compared to medical therapy, from the perspective of the UK National Health Service
Antimicrobial Peptides and Skin: A Paradigm of Translational Medicine
Antimicrobial peptides (AMPs) are small, cationic, amphiphilic peptides with broad-spectrum microbicidal activity against both bacteria and fungi. In mammals, AMPs form the first line of host defense against infections and generally play an important role as effector agents of the innate immune system. The AMP era was born more than 6 decades ago when the first cationic cyclic peptide antibiotics, namely polymyxins and tyrothricin, found their way into clinical use. Due to the good clinical experience in the treatment of, for example, infections of mucus membranes as well as the subsequent understanding of mode of action, AMPs are now considered for treatment of inflammatory skin diseases and for improving healing of infected wounds. Based on the preclinical findings, including pathobiochemistry and molecular medicine, targeted therapy strategies are developed and first results indicate that AMPs influence processes of diseased skin. Importantly, in contrast to other antibiotics, AMPs do not seem to propagate the development of antibiotic-resistant micro-organisms. Therefore, AMPs should be tested in clinical trials for their efficacy and tolerability in inflammatory skin diseases and chronic wounds. Apart from possible fields of application, these peptides appear suited as an example of the paradigm of translational medicine for skin diseases which is today seen as a `two-way road' - from bench to bedside and backwards from bedside to bench. Copyright (c) 2012 S. Karger AG, Base
Three-year survival of single- and two-surface ART restorations in a high-caries child population
The aim of this study was to evaluate the survival of single- and two-surface atraumatic restorative treatment (ART) restorations in the primary and permanent dentitions of children from a high-caries population, in a field setting. The study was conducted in the rainforest of Suriname, South America. ART restorations, made by four Dutch dentists, were evaluated after 6 months, 1, 2, and 3 years. Four hundred seventy-five ART restorations were placed in the primary dentition and 54 in first permanent molars of 194 children (mean age 6.09 ± 0.48 years). Three-year cumulative survivals of single- and two-surface ART restorations in the primary dentition were 43.4 and 12.2%, respectively. Main failure characteristics were gross marginal defects and total or partial losses. Three-year cumulative survival for single-surface ART restorations in the permanent dentition was 29.6%. Main failure characteristics were secondary caries and gross marginal defects. An operator effect was found only for two-surface restorations. The results show extremely low survival rates for single- and two-surface ART restorations in the primary and permanent dentitions. The variable success for ART may initiate further discussion about alternative treatment strategies, especially in those situations where choices have to be made with respect to a well-balanced, cost-effective package of basic oral health care
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