BACKGROUND The initiation of re-entrant cardiac arrhythmias is associated with increased dispersion of repolarisation, but the details are difficult to investigate either experimentally or clinically. We used a computational model of cardiac tissue to study systematically the association between action potential duration (APD) dispersion and susceptibility to re-entry. METHODS We simulated a ...

Diffraction places a fundamental limitation on the distance an optical beam propagates before its size increases and spatial details blur. We show here that imposing a judicious correlation between spatial and spectral degrees of freedom of a pulsed beam can render its transverse spatial profile independent of location along the propagation axis, thereby arresting the spread of the time-average...

Using a spatial percentile approach, we explore the magnitude of temperature anomalies across the Northern and Southern Hemispheres. Linear trends in spatial percentile series are estimated for 1881–2013, the most recent 30 year period (1984–2013), and 1998–2013. All spatial percentiles in both hemispheres show increases from 1881 to 2013, but warming occurred unevenly via modification of cold ...

This paper secures solitary waves and conservation laws to the familiar Korteweg–de Vries equation Gardner’s with three dispersion sources. The traveling wave hypothesis leads emergence of such waves. sources are spatial dispersion, spatio–temporal dual-emporal–spatial dispersion. enumerated for these models, evolved from multiplier approach. conserved quantities computed solutions that were re...

We study the intermittency of fluid velocities in porous media and its relation to anomalous dispersion. Lagrangian velocities measured at equidistant points along streamlines are shown to form a spatial Markov process. As a consequence of this remarkable property, the dispersion of fluid particles can be described by a continuous time random walk with correlated temporal increments. This new d...

Concentrated animal feeding operations (CAFOs) produce large amounts of animal waste, which potentially pollutes air, soil and water and affects human health if not appropriately managed. This study uses meteorological and CAFO data and applies an air pollution dispersion model (CALPUFF) to estimate ammonia concentrations at locations downwind of hog CAFOs and to evaluate the disproportionate e...

Empirical studies on the economic base multiplier concept have been highly limited in their spatial scope. The aim of this research is to provide new insights into the study of base multipliers by examining their spatial distribution over space. Base multipliers pertaining to the 923 districts in Turkey, varying between 1,268 and 807,934 in population, are estimated for the year 2000 using aggr...

In this paper, we discuss observations of temperature variability in the tidal portion of the San Joaquin River in California. The San Joaquin River makes up the southern portion of the Sacramento San Joaquin Delta, the eastern end of San Francisco Bay. Observations made in August 2004 and August 2005 show significant diurnal variations in temperature in response to surface heat exchange. Howev...

We examine the effects on the Fundamental Plane (FP) of structural departures from an R galaxy light profile. We also explore the use of spatial (i.e. volumetric) as well as projected galaxy parameters. We fit the Sersic R law to the V-band light profiles of 26 E/S0 Virgo galaxies, where n is a shape parameter that allows for structural differences amongst the profiles. The galaxy light profile...

High concentrations of ozone in the Houston/Galveston area are associated with industrial plumes of highly reactive hydrocarbons, mixed with NOx. The emissions leading to these plumes can have significant temporal variability, and photochemical modeling indicates that the emissions variability can lead to increases and decreases of 10-50 ppb, or more, in ozone concentrations. Therefore, in regi...