Water distribution systems are vulnerable to intentional, along with accidental, contamination of the water supply. Contamination warning systems have been developed with the goal of providing an early detection of contamination. A network of water quality sensors deployed in a system can alert an operator of a potential contamination event, but these sensors must be placed in locations that ma...

Motivated by WMAP’s confirmation of an anomalously low value of the quadrupole moment of the CMB temperature fluctuations, we investigate the effects on the CMB of cutting off the primordial power spectrum P (k) at low wave numbers. This could arise, for example, from a break in the inflaton potential, a prior period of matter or radiation domination, or an oscillating scalar field which couple...

ERRATUM A third possible explanation for the X-ray emission from the z = 2.156 radio galaxy 1138−262 is thermal emission from a very dense, sub-cluster 'halo', perhaps associated with the (forming) cD galaxy on a scale ≤ 100 kpc. For instance, increasing the gas density from 0.01 cm −3 to 0.1 cm −3 would decrease the required hot gas mass by the same factor, and could possibly alleviate constra...

Motivated by the recent investigations on instabilities caused by Schwoebel barriers during growth and their effects on growth or sublimation by step flows, we have investigated, using the Stillinger-Weber potential, how this step edge barrier arises for the two high symmetry steps on 1×1 reconstructed Si(111). Relative to a barrier of 0.97 ± 0.07 eV on the surface, we find additional (Schwoebe...

Non-equilibrium molecular dynamics simulations were performed to study the thermodynamic, structural, and dynamical properties of the single-component Lennard-Jones and the Kob-Andersen binary Lennard-Jones liquids. Both systems are known to have strong correlations between equilibrium thermal fluctuations of virial and potential energy. Such systems have good isomorphs (curves in the thermodyn...

We discuss the fate of certain tachyonic closed string theories from two perspectives. In both cases our approach involves studying directly configurations with finite negative treelevel cosmological constant. Closed string analogues of orientifolds, which carry negative tension, are argued to represent the minima of the tachyon potential in some cases. In other cases, we make use of the fact, ...

BACKGROUND There is often a need in flow cytometry to display and analyze histograms at resolutions lower than those native to the data. It is common, for example, to analyze DNA histograms at 256-channel resolution, even though the data were acquired at 1,024 channels or more. The most common method for reducing resolution, referred to as the consecutive summation (CS) method, can introduce di...

The turbulent flow field generated in a baffled stirred tank was computed by large eddy simulation (LED) and the flow field was developed using the Sliding Mesh (SM) approach. In this CFD study, mixing times and power number have been determined for a vessel agitated by a 6-blade Rushton turbine. The predicted results were compared with the published experimental data. The satisfactory results ...