[1] The return-stroke propagation speeds of five strokes from a seven-stroke triggered lightning flash are measured, with a 2 ns sampling interval, using a vertical array of photodiodes. Various methods for determining the reference point to be tracked are explored, and the speed is seen to vary over nearly an order of magnitude depending upon which method is chosen. The speeds are generally in...

We present a new framework for creating elegant algorithms for exact uniform sampling of important Catalan structures, such as triangulations of convex polygons, Dyck words, monotonic lattice paths and mountain ranges. Along with sampling, we obtain optimal coding, and optimal number of random bits required for the algorithm. The framework is based on an original two-parameter recursive relatio...

Free energy simulations are an established computational tool in modelling chemical change in the condensed phase. However, sampling of kinetically distinct substates remains a challenge to these approaches. As a route to addressing this, we link the methods of thermodynamic integration (TI) and swarm-enhanced sampling molecular dynamics (sesMD), where simulation replicas interact cooperatively...

1. Two common species of acorn barnacle, Chthamalus montagui and C. stellatus , with similar resource needs, occur together on rocky shores of NW Europe but differ in their adult distribution over two environmental gradients, wave exposure and vertical height on the shore. 2. A sampling programme was undertaken over 2 years to determine the causal mechanisms of this differential distribution. T...

Hierarchical structure in bird-habitat associations can arise from hierarchical structure in environmental variables and from the scale-dependent responses of birds to habitat. Hierarchical structure in environmental variables is expected to result from interactions between variables that differ in grain size (spatial resolution) and frequency, and should occur commonly. Birds cannot accurately...

PURPOSE In rowing ergometry, blood for determining lactate concentration can be removed from the toe tip without the rower having to stop. The purpose of the study was to examine whether sampling blood from the toe versus the earlobe would affect lactate threshold (Tlac) determination. METHODS Ten physically active males (mean ± age 21.2 ± 2.3 y; stature 179.2 ± 7.5 cm; body mass 81.7 ± 12.7 ...

Surface roughness characterization of thermally sprayed and precision machined WC–Co and Alloy-625 coatings was carried out. The objectives were to demonstrate that such difficult-to-machine coating surfaces could be machined with commercial machines and tools, and to characterize the surface finish of the machined coatings. The coatings were obtained using two thermal spraying processes: arc s...

The potential generality of local processes in determining spatial patterns of molluscan assemblages in turfs of Corallina officinalis is evaluated by testing hypotheses about consistency in ecological pattern on shores in Australia, Ireland and Chile. Identical sampling protocols on 2 shores in each country were used to test 2 specific hypotheses: (1) that molluscan assemblages vary significan...

OBJECTIVE To explore the effect of the educational level of the head of household on the prevalence of malnutrition in Saudi children. METHODS The study was conducted over 2 years in 2004 and 2005 in all regions of the Kingdom of Saudi Arabia (KSA). The design consisted of a stratified multistage probability random sampling of the population of the KSA. The educational level of the heads of t...

We present a real-time method for rendering global illumination effects from large area and environmental lights on dynamic height fields. In contrast to previous work, our method handles inter-reflections (indirect lighting) and non-diffuse surfaces. To reduce sampling, we construct one multi-resolution pyramid for height variation to compute direct shadows, and another pyramid for each indire...