5,112 research outputs found
A Variational Principle for the Asymptotic Speed of Fronts of the Density Dependent Diffusion--Reaction Equation
We show that the minimal speed for the existence of monotonic fronts of the
equation with , and in
derives from a variational principle. The variational principle allows
to calculate, in principle, the exact speed for arbitrary . The case
when is included as an extension of the results.Comment: Latex, postcript figure availabl
Spontaneous flow transition in active polar gels
We study theoretically the effects of confinement on active polar gels such
as the actin network of eukaryotic cells. Using generalized hydrodynamics
equations derived for active gels, we predict, in the case of quasi
one-dimensional geometry, a spontaneous flow transition from a homogeneously
polarized immobile state for small thicknesses, to a perturbed flowing state
for larger thicknesses. The transition is not driven by an external field but
by the activity of the system. We suggest several possible experimental
realizations.Comment: 7 pages, 3 figures. To appear in Europhys. Let
A Nuclear Physics Program at the ATLAS Experiment at the CERN Large Hadron Collider
The ATLAS collaboration has significant interest in the physics of
ultra-relativistic heavy ion collisions. We submitted a Letter of Intent to the
United States Department of Energy in March 2002. The following document is a
slightly modified version of that LOI. More details are available at:
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/SM/ionsComment: Letter of Intent submitted to the United States Department of Energy
Nuclear Physics Division in March 2002 (revised version
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