Les bénéfices d'un programme d'exercice physique sur la capacité de marche des patients avec claudication intermittente peuvent-ils perdurer six mois après la fin du programme? Données préliminaires

Introduction. L'artériopathie oblitérante des membres inférieurs d'origine athéromateuse, principale cause de claudication intermittente, est un problème de santé publique en Suisse. Typiquement, les patients avec claudication intermittente manifestent des douleurs à l'effort qui limitent leur capacité de marche. L'exercice physique est la pierre angulaire du traitement de la claudication intermittente avec des effets bénéfiques sur la capacité de marche largement démontrés dans la littérature. Cependant, peu d'études ont examiné la persistance à long terme des bénéfices de l'exercice physique. Objectif. Déterminer si l'augmentation de la capacité de marche des patients avec claudication intermittente observée en réponse à un programme d'exercice peut perdurer 6 mois après la fin du programme. Méthodes. Dix patients avec une claudication intermittente et ayant suivi un programme d'exercice supervisé de 3 mois ont été inclus dans cette étude. Avant le début du programme, à la fin du programme, et 6 mois après la fin du programme, les distances de marche asymptomatique et maximale ont été déterminées par un test d'effort sur tapis roulant tandis que la distance totale de marche parcourue en 6 minutes a été évaluée par le test de marche de 6 minutes. L'index de pression cheville/bras (ABI) et l'index de pression orteil/bras (TBI) ont également été mesurés à ces différents temps. Résultats. Comme attendu, la distance de marche maximale et la distance totale parcourue en 6 minutes ont été significativement augmentées respectivement de 118% et 22% à la fin du programme d'exercice (p<0.05 versus avant le programme), tandis qu'une tendance à l'augmentation a été observée pour la distance de marche asymptomatique. Six mois après la fin du programme, la distance totale de marche parcourue en 6 minutes est toujours significativement augmentée comparé à avant le programme (p<0.05). La distance maximale de marche à 6 mois après la fin du programme est supérieure à celle obtenue après le programme (773±578 m versus 613±511, p<0.05). Les valeurs d'ABI et TBI ne sont pas significativement différentes aux différents temps de l'étude. Conclusion. Ce travail démontre qu'un exercice supervisé de 3 mois est efficace pour générer sur le long terme des bénéfices sur la capacité de marche des patients avec claudication intermittente. D'autres études sont néanmoins nécessaires pour confirmer ce résultat et déterminer les mécanismes responsables de ces bénéfices. Ce travail confirme la relevance clinique de l'exercice supervisé pour le traitement à long terme de la claudication intermittente

Surgery during holiday periods and prognosis in oesophageal cancer: a population-based nationwide Swedish cohort study

OBJECTIVE: Previous studies indicate an increased short-term and long-term mortality from major cancer surgery performed towards the end of the working week or during the weekend. We hypothesised that the prognosis after major cancer surgery is also negatively influenced by surgery conducted during holiday periods. SETTING: Population-based nationwide Swedish cohort study. PARTICIPANTS: Patients undergoing oesophagectomy for oesophageal cancer between 1987 and 2010. Among 1820 included patients, 206 (11.3%) and 373 (20.5%) patients were operated on during narrow and wide holiday periods, respectively. INTERVENTIONS: Narrow (7 weeks) and wide (14 weeks) Swedish holiday periods. PRIMARY AND SECONDARY OUTCOME MEASURES: 90-day all-cause, 5-year all-cause and 5-year disease-specific mortality. RESULTS: Narrow holiday period did not increase all-cause 90-day (HR=0.84, 95% CI 0.53 to 1.33), all-cause 5-year (HR=1.01, 95% CI 0.85 to 1.21) or disease-specific 5-year mortality (HR=1.04, 95% CI 0.87 to 1.26). Similarly, wide holiday period did not increase the risk of 90-day (HR=0.79, 95% CI 0.55 to 1.13), all-cause 5-year (HR=0.96, 95% CI 0.84 to 1.1) or disease-specific 5-year mortality (HR=1.03, 95% CI 0.89 to 1.19). CONCLUSIONS: No measurable effects of holiday periods on short-term or longer term mortality following surgery for oesophageal cancer were observed in this population-based study, indicating that an adequate surgical experience was maintained during holiday periods

On "the complete basis set limit" and plane-wave methods in first-principles simulations of water

Water structure, measured by the height of the first peak in oxygen-oxygen radial distributions, is converged with respect to plane-wave basis energy cutoffs for ab initio molecular dynamics simulations, confirming the reliability of plane-wave methods.Comment: 9 pages, 3 figure

Supernovae data and perturbative deviation from homogeneity

We show that a spherically symmetric perturbation of a dust dominated $\Omega=1$ FRW universe in the Newtonian gauge can lead to an apparent acceleration of standard candles and provide a fit to the magnitude-redshift relation inferred from the supernovae data, while the perturbation in the gravitational potential remains small at all scales. We also demonstrate that the supernovae data does not necessarily imply the presence of some additional non-perturbative contribution by showing that any Lemaitre-Tolman-Bondi model fitting the supernovae data (with appropriate initial conditions) will be equivalent to a perturbed FRW spacetime along the past light cone.Comment: 8 pages, 3 figures; v2: 1 figure added, references added/updated, minor modifications and clarifications, matches published versio

Obituary for Walter Kohn (1923–2016)

Walter Kohn (Figure 1) is one of the most cited scientists of our time, who died on 19 April 2016 in Santa Barbara, CA, USA. [...

An Improved High Order Finite Difference Method for Non-conforming Grid Interfaces for the Wave Equation

This paper presents an extension of a recently developed high order finite difference method for the wave equation on a grid with non-conforming interfaces. The stability proof of the existing methods relies on the interpolation operators being norm-contracting, which is satisfied by the second and fourth order operators, but not by the sixth order operator. We construct new penalty terms to impose interface conditions such that the stability proof does not require the norm-contracting condition. As a consequence, the sixth order accurate scheme is also provably stable. Numerical experiments demonstrate the improved stability and accuracy property

Higher order finite difference schemes for the magnetic induction equations

We describe high order accurate and stable finite difference schemes for the initial-boundary value problem associated with the magnetic induction equations. These equations model the evolution of a magnetic field due to a given velocity field. The finite difference schemes are based on Summation by Parts (SBP) operators for spatial derivatives and a Simultaneous Approximation Term (SAT) technique for imposing boundary conditions. We present various numerical experiments that demonstrate both the stability as well as high order of accuracy of the schemes.Comment: 20 page

New, efficient, and accurate high order derivative and dissipation operators satisfying summation by parts, and applications in three-dimensional multi-block evolutions

We construct new, efficient, and accurate high-order finite differencing operators which satisfy summation by parts. Since these operators are not uniquely defined, we consider several optimization criteria: minimizing the bandwidth, the truncation error on the boundary points, the spectral radius, or a combination of these. We examine in detail a set of operators that are up to tenth order accurate in the interior, and we surprisingly find that a combination of these optimizations can improve the operators' spectral radius and accuracy by orders of magnitude in certain cases. We also construct high-order dissipation operators that are compatible with these new finite difference operators and which are semi-definite with respect to the appropriate summation by parts scalar product. We test the stability and accuracy of these new difference and dissipation operators by evolving a three-dimensional scalar wave equation on a spherical domain consisting of seven blocks, each discretized with a structured grid, and connected through penalty boundary conditions.Comment: 16 pages, 9 figures. The files with the coefficients for the derivative and dissipation operators can be accessed by downloading the source code for the document. The files are located in the "coeffs" subdirector