A semi-Lagrangian scheme for the game pp-Laplacian via pp-averaging

We present and analyze an approximation scheme for the two-dimensional game $p$-Laplacian in the framework of viscosity solutions. The approximation is based on a semi-Lagrangian scheme which exploits the idea of $p$-averages. We study the properties of the scheme and prove that it converges, in particular cases, to the viscosity solution of the game $p$-Laplacian. We also present a numerical implementation of the scheme for different values of $p$; the numerical tests show that the scheme is accurate.Comment: 34 pages, 3 figures. To appear on Applied Numerical Mathematic

Supra-oscillatory critical temperature dependence of Nb-Ho bilayers

We investigate the critical temperature Tc of a thin s-wave superconductor (Nb) proximity coupled to a helical rare earth ferromagnet (Ho). As a function of the Ho layer thickness, we observe multiple oscillations of Tc superimposed on a slow decay, that we attribute to the influence of the Ho on the Nb proximity effect. Because of Ho inhomogeneous magnetization, singlet and triplet pair correlations are present in the bilayers. We take both into consideration when solving the self consistent Bogoliubov-de Gennes equations, and we observe a reasonable agreement. We also observe non-trivial transitions into the superconducting state, the zero resistance state being attained after two successive transitions which appear to be associated with the magnetic structure of Ho.Comment: Main article: 5 pages, 4 figures; Supplementary materials: 4 pages, 5 figure

The expanding bipolar shell of the helium nova V445 Puppis

From multi-epoch adaptive optics imaging and integral field unit spectroscopy, we report the discovery of an expanding and narrowly confined bipolar shell surrounding the helium nova V445 Puppis (Nova Puppis 2000). An equatorial dust disc obscures the nova remnant, and the outflow is characterized by a large polar outflow velocity of 6720 +/- 650 km s(-1) and knots moving at even larger velocities of 8450 +/- 570 km s(-1). We derive an expansion parallax distance of 8.2 +/- 0.5 kpc and deduce a pre-outburst luminosity of the underlying binary of log L/L-circle dot = 4.34 +/- 0.36. The derived luminosity suggests that V445 Puppis probably contains a massive white dwarf accreting at high rate from a helium star companion making it part of a population of binary stars that potentially lead to supernova Ia explosions due to accumulation of helium-rich material on the surface of a massive white dwarf

Programma beheer : leren van omliggende landen

De EU schrijft voor dat regelingen voor agrarisch natuurbeheer geëvalueerd worden op effectiviteit en efficiëntie, maar schrijft geen methodiek voor. Dit artikel vergelijkt de situatie in Engeland, Noordrijn-Westfalen, Vlaanderen, Frankrijk en Denemarken met die van Nederland. Daarbij ligt de nadruk op de vraag in hoeverre regelingen centraal dan wel decentraal worden aangestuur

The Persuasiveness of Child-Targeted Endorsement Strategies: A Systematic Review

Several European and U.S. reviews have established the link between food marketing and childhood obesity (EU Pledge, 2012; FTC, 2006; Persson, Soroko, Musicus & Lobstein, 2012), which has stimulated researchers to investigate the effects of the most prevalent child-targeted marketing technique: the use of endorsing characters. This systematic review of these studies (15 identified; participants age 3-12 years) focuses on three important questions: (a) Does a basic endorser effect exist?, (b) Is the strength of the endorsement effect influenced by endorser type?, and (c) Does the endorsement strength differ according to the type of food being promoted

Studies of resistance switching effects in metal/YBa2Cu3O7-x interface junctions

Current-voltage characteristics of planar junctions formed by an epitaxial c-axis oriented YBa2Cu3O7-x thin film micro-bridge and Ag counter-electrode were measured in the temperature range from 4.2 K to 300 K. A hysteretic behavior related to switching of the junction resistance from a high-resistive to a low-resistive state and vice-versa was observed and analyzed in terms of the maximal current bias and temperature dependence. The same effects were observed on a sub-micrometer scale YBa2Cu3O7-x thin film - PtIr point contact junctions using Scanning Tunneling Microscope. These phenomena are discussed within a diffusion model, describing an oxygen vacancy drift in YBa2Cu3O7-x films in the nano-scale vicinity of the junction interface under applied electrical fields.Comment: To be published in Applied Surface Science

Ubiquitous late competence genes in Bacillus species indicate the presence of functional DNA uptake machineries

P>Natural competence for genetic transformation, i.e. the ability to take up DNA and stably integrate it in the genome, has so far only been observed in the bacterial kingdom (both in Gram-negative and Gram-positive species) and may contribute to survival under adverse growth conditions. Bacillus subtilis, the model organism for the Bacillus genus, possesses a well-characterized competence machinery. Phylogenetic analysis of several genome sequences of different Bacillus species reveals the presence of many, but not all genes potentially involved in competence and its regulation. The recent demonstration of functional DNA uptake by B. cereus supports the significance of our genome analyses and shows that the ability for functional DNA uptake might be widespread among Bacilli