94,167 research outputs found
Thermodynamics of D-brane Probes
We discuss the dynamics and thermodynamics of particle and D-brane probes
moving in non-extremal black hole/brane backgrounds. When a probe falls from
asymptotic infinity to the horizon, it transforms its potential energy into
heat, , which is absorbed by the black hole in a way consistent with the
first law of thermodynamics. We show that the same remains true in the
near-horizon limit, for BPS probes only, with the BPS probe moving from AdS
infinity to the horizon. This is a quantitative indication that the brane-probe
reaching the horizon corresponds to thermalization in gauge theory. It is shown
that this relation provides a way to reliably compute the entropy away from the
extremal limit (towards the Schwarzschild limit).Comment: 12 pages; Based on talks presented at the midterm meeting of the TMR
network "Physics beyond the standard model," held in Trieste in March 1999,
and at the 1998 Corfu Summer Institute on Elementary Particle Physic
String loop corrections to gauge and Yukawa couplings
We report on the recent progress in computing the effective supergravity
action from superstring scattering amplitudes beyond the tree approximation. We
discuss the moduli-dependent string loop corrections to gauge, gravitational
and Yukawa couplings.Comment: 11 pages, CPTH-C218.0193 (Based on talks presented at the Rome
Workshop STRINGS 92, at the 7th Meeting of the American Physical Society, and
at the 26th Erice Workshop: ``From Superstrings to Supergravity"
Duality of N=2 Heterotic -- Type I Compactifications in Four Dimensions
We discuss type I -- heterotic duality in four-dimensional models obtained as
a Coulomb phase of the six-dimensional U(16) orientifold model compactified on
T^2 with arbitrary SU(16) Wilson lines. We show that Kahler potentials, gauge
threshold corrections and the infinite tower of higher derivative F-terms agree
in the limit that corresponds to weak coupling, large T^2 heterotic
compactifications. On the type I side, all these quantities are completely
determined by the spectrum of N=2 BPS states that originate from D=6 massless
superstring modes.Comment: 22 pages, LaTeX; typos corrected and references adde
Cost effectiveness of conventional versus LANDSAT use data for hydrologic modeling
Six case studies were analyzed to investigate the cost effectiveness of using land use data obtained from LANDSAT as opposed to conventionally obtained data. A procedure was developed to determine the relative effectiveness of the two alternative means of acquiring data for hydrological modelling. The cost of conventionally acquired data ranged between 16,000 for the six test basins. Information based on LANDSAT imagery cost between 5,000. Results of the effectiveness analysis shows the differences between the two methods are insignificant. From the cost comparison and the act that each method, conventional and LANDSAT, is shown to be equally effective in developing land use data for hydrologic studies, the cost effectiveness of the conventional or LANDSAT method is found to be a function of basin size for the six test watersheds analyzed. The LANDSAT approach is cost effective for areas containing more than 10 square miles
Distributed supply chain simulation in GRIDS
Amongst the majority of work done in supply chain simulation, papers have emerged that examine the area of model distribution. The executions of simulations on distributed hosts as a coupled model require both coordination and facilitating infrastructure. A distributed environment, the Generic Runtime Infrastructure for Distributed Simulation (GRIDS) is suggested to provide the bonding requirements for such a model. The advantages of transparently connecting the distributed components of a supply chain simulation allow the construction of a conceptual simulation while releasing the modeler from the complexities of the underlying network. The infrastructure presented demonstrates scalability without losing flexibility for future extensions based on open industry standard
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