673 research outputs found
Restoring Prosperity: The State Role in Revitalizing America's Older Industrial Cities
Presents a five-part agenda and organizing plan to reinvigorate the nation's older industrial cities, and aims to mobilize governors, legislative leaders, and local constituencies toward advancing urban reform
A force balance system for the measurement of skin friction drag force in the presence of large vibrations and temperatures
Design of counterbalance system for skin friction drag measurements on hypersonic vehicle
Multi-component Force Balance Control Systems Final Report
Technique and apparatus for drag, lift, and pitch force measurements in hypersonic wind tunnel
Investigation of Systems and Techniques for Multicomponent Microforce Measurements on Wind Tunnel Models Semiannual Status Report, 15 Jul. 1965 - 15 Jan. 1966
Skin friction drag sensor and multicomponent microforce wind tunnel balance syste
Cohomology of groups of diffeomorphims related to the modules of differential operators on a smooth manifold
Let be a manifold and be the cotangent bundle. We introduce a
1-cocycle on the group of diffeomorphisms of with values in the space of
linear differential operators acting on When is the
-dimensional sphere, , we use this 1-cocycle to compute the
first-cohomology group of the group of diffeomorphisms of , with
coefficients in the space of linear differential operators acting on
contravariant tensor fields.Comment: arxiv version is already officia
The definability criterions for convex projective polyhedral reflection groups
Following Vinberg, we find the criterions for a subgroup generated by
reflections \Gamma \subset \SL^{\pm}(n+1,\mathbb{R}) and its finite-index
subgroups to be definable over where is an integrally
closed Noetherian ring in the field . We apply the criterions for
groups generated by reflections that act cocompactly on irreducible properly
convex open subdomains of the -dimensional projective sphere. This gives a
method for constructing injective group homomorphisms from such Coxeter groups
to \SL^{\pm}(n+1,\mathbb{Z}). Finally we provide some examples of
\SL^{\pm}(n+1,\mathbb{Z})-representations of such Coxeter groups. In
particular, we consider simplicial reflection groups that are isomorphic to
hyperbolic simplicial groups and classify all the conjugacy classes of the
reflection subgroups in \SL^{\pm}(n+1,\mathbb{R}) that are definable over
. These were known by Goldman, Benoist, and so on previously.Comment: 31 pages, 8 figure
Consistent Anisotropic Repulsions for Simple Molecules
We extract atom-atom potentials from the effective spherical potentials that
suc cessfully model Hugoniot experiments on molecular fluids, e.g., and
. In the case of the resulting potentials compare very well with the
atom-atom potentials used in studies of solid-state propertie s, while for
they are considerably softer at short distances. Ground state (T=0K) and
room temperatu re calculations performed with the new potential resolve
the previous discrepancy between experimental and theoretical results.Comment: RevTeX, 5 figure
Turing instabilities in a mathematical model for signaling networks
GTPase molecules are important regulators in cells that continuously run
through an activation/deactivation and membrane-attachment/membrane-detachment
cycle. Activated GTPase is able to localize in parts of the membranes and to
induce cell polarity. As feedback loops contribute to the GTPase cycle and as
the coupling between membrane-bound and cytoplasmic processes introduces
different diffusion coefficients a Turing mechanism is a natural candidate for
this symmetry breaking. We formulate a mathematical model that couples a
reaction-diffusion system in the inner volume to a reaction-diffusion system on
the membrane via a flux condition and an attachment/detachment law at the
membrane. We present a reduction to a simpler non-local reaction-diffusion
model and perform a stability analysis and numerical simulations for this
reduction. Our model in principle does support Turing instabilities but only if
the lateral diffusion of inactivated GTPase is much faster than the diffusion
of activated GTPase.Comment: 23 pages, 5 figures; The final publication is available at
http://www.springerlink.com http://dx.doi.org/10.1007/s00285-011-0495-
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