We are interested in reaction-diffusion equations that model excitable media under the influence of an additive noise. In many models of this type, the homogeneous zero state is stable and interesting dynamics is observed only for certain initial data. In the presence of noise, the excitable media is stimulated and the noise may be sufficiently large to nucleate wave forms. In computations, we ...

We study the effect of small, randomly distributed obstacles on wave propagation in two-dimensional (2D) and 3D excitable media described by the Aliev–Panfilov model. We find that increasing the number of obstacles decreases the conduction velocity of plane waves and decreases the effective diffusion coefficient in the eikonal curvature equation. The presence of obstacles also increases the ind...

Direct growth on blood and screening agar for methicillin-resistant Staphylococcus aureus (MRSA) at a tropical surveillance site was compared with broth enrichment and subsequent growth on selective MRSA agar after international sample transport. In Madagascar, 1548 swabs from an MRSA surveillance study were assessed for growth on Columbia blood agar enriched with 5% sheep blood and MRSA screen...

Characteristically shaped bifacial points are stone artefacts with which the Middle Stone Age Still Bay techno-complex in Southern Africa is identified. Traditional approaches such as chaîne opératoire and two-dimensional metrics in combination with attribute analyses have been used to analyse variability within Still Bay point assemblages. Here we develop a protocol to extract and analyse high...

Controlling spatiotemporal chaos in excitable media by applying low-amplitude perturbations locally is of immediate applicability, e.g., in treating ventricular fibrillation, a fatal disturbance in the normal rhythmic functioning of the heart. We look at a mechanism of control by the local application of a series of biphasic pulses, i.e., involving both positive and negative stimulation. This r...

We describe automated methods for constructing nonisomorphism proofs for pairs of graphs. The proofs can be human-readable or machinereadable. We have developed an experimental implementation of an interactive webpage producing a proof of (non)isomorphism when given two graphs. Mathematics Subject Classification (2000). 05C60, 68R10, 05C25, 03B35.

We present a new concept to infer the meridional flow in the deep solar interior from global oscillation data. This concept is based on the estimation of the coupling strengths of p-mode eigenfunctions mediated by the meridional flow. We illustrate the performance of the method using simulations and present first inversion results of a large-scale flow component of the meridional flow obtained ...

In this study we have decoded bar codes by recognizing the human readable characters of the interpretation line printed below the bar pattern Using this approach we were able to successfully decode bar codes with a resolution of pixels per module