7,440 research outputs found
The nonlinear Bernstein-Schr\"odinger equation in Economics
In this paper we relate the Equilibrium Assignment Problem (EAP), which is
underlying in several economics models, to a system of nonlinear equations that
we call the "nonlinear Bernstein-Schr\"odinger system", which is well-known in
the linear case, but whose nonlinear extension does not seem to have been
studied. We apply this connection to derive an existence result for the EAP,
and an efficient computational method.Comment: 8 pages, submitted to Lecture Notes in Computer Scienc
Dilepton Production in Nucleon-Nucleon Reactions With and Without Hadronic Inelasticities
We calculate elementary proton-proton and neutron-proton bremsstrahlung and
their contribution to the invariant mass distribution. At 4.9 GeV, the
proton-proton contribution is larger than neutron-proton, but it is small
compared to recent data. We then make a first calculation of bremsstrahlung in
nucleon-nucleon reactions with multi-hadron final states. Again at 4.9 GeV, the
many-body bremsstrahlung is larger than simple nucleon-nucleon bremsstrahlung
by more than an order of magnitude in the low-mass region. When the
bremsstrahlung contributions are summed with Dalitz decay of the ,
radiative decay of the and from two-pion annihilation, the result
matches recent high statistics proton-proton data from the Dilepton
Spectrometer collaboration.Comment: 1+17 pages plus 11 PostScript figures uuencoded and appended,
McGill/93-9, TPI-MINN-93/18-
Azimuthal Asymmetry of Direct Photons in High Energy Nuclear Collisions
We show that a sizeable azimuthal asymmetry, characterized by a coefficient
v_2, is to be expected for direct photons produced in non-central high energy
nuclear collisions. This signal is generated by photons radiated by jets
interacting with the surrounding hot plasma. The anisotropy is out of phase by
an angle with respect to that associated with the elliptic anisotropy
of hadrons, leading to negative values of v_2. Such an asymmetry, if observed,
could be a signature for the presence of a quark gluon plasma and would
establish the importance of jet-plasma interactions as a source of
electromagnetic radiation.Comment: New title. Final versio
Impact of inertia, friction, and backlash upon force control in telemanipulation
The mechanical behavior of master controllers of telemanipulators has been a concern of both designers and implementors of telerobotic systems. In general, the literature recommends that telemanipulator systems be constructed that minimize inertia, friction, and backlash in an effort to improve telemanipulative performance. For the most part, these recommendations are founded upon theoretical analysis or simply intuition. Although these recommendations are not challenged on their merit, the material results are measured of building and fielding telemanipulators that possess less than ideal mechanical behaviors. Experiments are described in which forces in a mechanical system with human input are evaluated as a function of mechanical characteristics such as inertia, friction, and backlash. Results indicate that the ability of the human to maintain gripping forces was relatively unaffected by dynamic characteristics in the range studied, suggesting that telemanipulator design in this range should be based on task level force control requirements rather than human factors
Anion receptor chemistry: highlights from 2011 and 2012
This review covers advances in anion complexation in the years 2011 and 2012. The review covers both organic and inorganic systems and also highlights the applications to which anion receptors can be applied such as self-assembly and molecular architecture, sensing, catalysis and anion transport
Properties of the phi meson at high temperatures and densities
We calculate the spectral density of the phi meson in a hot bath of nucleons
and pions using a general formalism relating self-energy to the forward
scattering amplitude (FSA). In order to describe the low energy FSA, we use
experimental data along with a background term. For the high energy FSA, a
Regge parameterization is employed. We verify the resulting FSA using
dispersion techniques. We find that the position of the peak of the spectral
density is slightly shifted from its vacuum position and that its width is
considerably increased. The width of the spectral density at a temperature of
150 MeV and at normal nuclear density is more than 90 MeV.Comment: 4 pages, 5 figures, Poster presented at Quark Matter 200
High momentum lepton pairs from jet-plasma interactions
We discuss the emission of high momentum lepton pairs (p_T>4 GeV) with low
invariant masses (M << p_T) in central Au+Au collisions at RHIC
(\sqrt{s_{NN}}=200 GeV). The spectra of dileptons produced through interactions
of quark and antiquark jets with the quark-gluon plasma (QGP) have been
calculated. Annihilation and Compton scattering processes, as well as processes
benefitting from collinear enhancement, including Landau-Pomeranchuk-Migdal
(LPM) effects, are calculated and convolved with a one dimensional hydrodynamic
expansion. The jet-induced contributions are compared to thermal dilepton
emission and Drell-Yan processes, and are found to dominate around p_T=4 GeV.Comment: Parallel talk given at QM2006, Shanghai November 2006. 4 pages, 3
figure
Highly effective yet simple transmembrane anion transporters based upon ortho-phenylenediamine bis-ureas
Simple, highly fluorinated receptors are shown to function as highly effective transmembrane anion antiporters with the most active transporters rivalling the transport efficacy of natural anion transporter prodigiosin for bicarbonate
Heavy Quark Potential at Finite Temperature Using the Holographic Correspondence
We revisit the calculation of a heavy quark potential in N =4 supersymmetric
Yang-Mills theory at finite temperature using the AdS/CFT correspondence. As is
widely known, the potential calculated in the pioneering works of Rey et al.
and Brandhuber et al. is zero for separation distances r between the quark and
the anti-quark above a certain critical separation, at which the potential has
a kink. We point out that by analytically continuing the string configurations
into the complex plane, and using a slightly different renormalization
subtraction, one obtains a smooth non-zero (negative definite) potential
without a kink. The obtained potential also has a non-zero imaginary
(absorptive) part for separations r > r_c = 0.870/\pi T . At large separations
r the real part of the potential does not exhibit the exponential Debye falloff
expected from perturbation theory and instead falls off as a power law,
proportional to 1/r^4 for r > r_0 = 2.702 / \pi T.Comment: 5 pages, 3 figures. Title modified. Discussion extended and
references modifie
Typical properties of optimal growth in the Von Neumann expanding model for large random economies
We calculate the optimal solutions of the fully heterogeneous Von Neumann
expansion problem with processes and goods in the limit .
This model provides an elementary description of the growth of a production
economy in the long run. The system turns from a contracting to an expanding
phase as increases beyond . The solution is characterized by a universal
behavior, independent of the parameters of the disorder statistics. Associating
technological innovation to an increase of , we find that while such an
increase has a large positive impact on long term growth when , its
effect on technologically advanced economies () is very weak.Comment: 8 pages, 1 figur
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