Digital information is accumulating at an astounding rate, straining our ability to store and archive it. DNA is among the most dense and stable information media known. The development of new technologies in both DNA synthesis and sequencing make DNA an increasingly feasible digital storage medium. We developed a strategy to encode arbitrary digital information in DNA, wrote a 5.27-megabit boo...

The visual perception of contours by the brain is selective. When embedded within a noisy background, closed contours are detected faster, and with higher certainty, than open contours. We investigate this phenomenon theoretically with the paradigmatic excitable FitzHughNagumo model, by considering a set of locally coupled oscillators subject to local uncorrelated noise. Noise is needed to over...

We propose a new method of volume hologram multiplexing/demultiplexing in noncentrosymmetric media. Volume holograms may be multiplexed by tuning the material parameters of the recording medium (such as refractive index or lattice parameters) while keeping the external parameters (wavelength and angles) fixed. For example, an external dc electric field alters the index of refraction through the...

Iron and titanium form two known stable intermetallic compounds, FeTi and Fe2Ti. exists above 1000°C , decomposing to FeTi and T i below that temperature. We have briefly noted previousl;’ that one of these compounds, FeTi, will react directly with hydrogen to form a n easily decomposed hydride which may be useful as a hydrogen storage medium. Our primary purpose here is to discuss the Fe-Ti-H ...

T he topic of the “credit crunch” received considerable attention during the early 1990s. As a result, several initiatives aimed at eliminating regulatory disincentives to lending were put in place. For example, documentation requirements recently were reduced to the legal minimum for loans to small and medium-sized businesses. Also, examiners and bankers were encouraged to emphasize the charac...

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...