Effects of Anisotropy in QED3 from Dyson-Schwinger equations in a box

We investigate the effect of anisotropies in the fermion velocities of 2+1 dimensional QED on the critical number N_f^c of fermions for dynamical mass generation. Our framework are the Dyson-Schwinger equations for the gauge boson and fermion propagators formulated in a finite volume. In contrast to previous Dyson-Schwinger studies we do not rely on an expansion in small anisotropies but keep the full velocity dependence of fermion equations intact. As result we find sizable variations of N_f^c away from the isotropic point in agreement with other approaches. We discuss the relevance of our findings for models of high-T_c superconductors.Comment: 9 pages, 7 figures, v2: minor changes, typos corrected, version accepted by PR

Added value of bleach sedimentation microscopy for diagnosis of pulmonary tuberculosis: cost-effectiveness study

IUATLD Conference, Paris, 200

Non-scattering wavenumbers and far field invisibility for a finite set of incident/scattering directions

We investigate a time harmonic acoustic scattering problem by a penetrable inclusion with compact support embedded in the free space. We consider cases where an observer can produce incident plane waves and measure the far field pattern of the resulting scattered field only in a finite set of directions. In this context, we say that a wavenumber is a non-scattering wavenumber if the associated relative scattering matrix has a non trivial kernel. Under certain assumptions on the physical coefficients of the inclusion, we show that the non-scattering wavenumbers form a (possibly empty) discrete set. Then, in a second step, for a given real wavenumber and a given domain D, we present a constructive technique to prove that there exist inclusions supported in D for which the corresponding relative scattering matrix is null. These inclusions have the important property to be impossible to detect from far field measurements. The approach leads to a numerical algorithm which is described at the end of the paper and which allows to provide examples of (approximated) invisible inclusions.Comment: 20 pages, 7 figure

Coherent imaging of extended objects

When used with coherent light, optical imaging systems, even diffraction-limited, are inherently unable to reproduce both the amplitude and the phase of a two-dimensional field distribution because their impulse response function varies slowly from point to point (a property known as non-isoplanatism). For sufficiently small objects, this usually results in a phase distortion and has no impact on the measured intensity. Here, we show that the intensity distribution can also be dramatically distorted when objects of large extension or of special shapes are imaged. We illustrate the problem using two simple examples: the pinhole camera and the aberration-free thin lens. The effects predicted by our theorical analysis are also confirmed by experimental observations.Comment: 10 pages, 9 figures, submitted to Optics Communication

Emerging role of angiogenesis in adaptive and maladaptive right ventricular remodeling in pulmonary hypertension

Right ventricular (RV) function is the primary prognostic factor for both morbidity and mortality in pulmonary hypertension (PH). RV hypertrophy is initially an adaptive physiological response to increased overload; however, with persistent and/or progressive afterload increase, this response frequently transitions to more pathological maladaptive remodeling. The mechanisms and disease processes underlying this transition are mostly unknown. Angiogenesis has recently emerged as a major modifier of RV adaptation in the setting of pressure overload. A novel paradigm has emerged that suggests that angiogenesis and angiogenic signaling are required for RV adaptation to afterload increases and that impaired and/or insufficient angiogenesis is a major driver of RV decompensation. Here, we summarize our current understanding of the concepts of maladaptive and adaptive RV remodeling, discuss the current literature on angiogenesis in the adapted and failing RV, and identify potential therapeutic approaches targeting angiogenesis in RV failure

Effectiveness of Self-Care Education on the Perceived Quality of Life in Adults with a Tracheostomy

Background: A tracheostomy is an operative procedure performed to create a stable surgical airway for patients with respiratory compromise due to a variety of clinical reasons. Living with a tracheostomy has tremendous impact on the patient as they experience alterations in their ability to eat, speak, breathe normally, and care for themselves. There is also a potential negative impact to their quality of life. Under ideal circumstances, the tracheostomy is a planned event and education is given to the patient prior to the procedure in an effort to lessen the impact and prepare them to cope with the expected life changes. However, in the acute care hospital setting, placing the tracheostomy has most often not been discussed prior to hospitalization, and frequently patient education is hindered by severity of illness and time constraints of clinical staff. An education initiative to impact self-care knowledge while the patient is still hospitalized is needed and may have a lasting impression on the patients’ perceived quality of life. Purpose: The purpose of this project was to examine the impact of an education intervention on the perceived quality of life for adult patients living with a tracheostomy. Methods: This study design was a single sample, longitudinal cohort. The data from a tracheostomy related quality of life questionnaire was evaluated during hospitalization and intended to be re-evaluated at approximately 30 days post-discharge. The data were analyzed for correlation coefficients and via independent samples t-tests. Results: The results of this study indicate a significant difference in tracheostomy related quality of life based on gender, age, and if the procedure was planned prior to hospital admission. Additionally, while not statistically significant, several strong correlations emerged from the data related to education level and age with various aspects of tracheostomy related quality of life. Conclusions: While limited by small sample size, the findings of this study suggest further research is warranted. Specifically, anecdotal findings indicate variations in tracheostomy care delivery between surgical services and nursing staff, and effort should be made to understand these variations in hopes to standardize and improve care