27,751 research outputs found
Validation of the communications link analysis and simulation system (CLASS)
CLASS (Communication Link Analysis and Simulation System) is a software package developed for NASA to predict the communication and tracking performance of the Tracking and Data Relay Satellite System (TDRSS) services. The methods used to verify CLASS are described. The usefulness of a software tool such as CLASS depends strongly on the reliability and accuracy of the results it produces. For this reason, considerable attention was paid to validation throughout the CLASS development
Electromagnetic form factors of the (rho) meson in light cone QCD sum rules
We investigate the electromagnetic form factors of the (rho) meson in light
cone QCD sum rules. We find that the ratio of the magnetic and charge form
factors is larger than two at all values of Q^2, (Q^2 >= 0.5 GeV^2). The values
of the individual form factors at fixed values of Q^2 predicted by the light
cone QCD sum rules are quite different compared to the results of other
approaches. These results can be checked in future, when more precise data on
(rho) meson form factors is available.Comment: 12 pages, 6 figures, LaTeX formatte
Sample-to-sample fluctuations and bond chaos in the -component spin glass
We calculate the finite size scaling of the sample-to-sample fluctuations of
the free energy of the component vector spin glass in the
large- limit. This is accomplished using a variant of the interpolating
Hamiltonian technique which is used to establish a connection between the free
energy fluctuations and bond chaos. The calculation of bond chaos then shows
that the scaling of the free energy fluctuaions with system size is with , and very likely
exactly.Comment: 12 pages, 1 figur
Magnetic domain formation in itinerant metamagnets
We examine the effects of long-range dipolar forces on metamagnetic
transitions and generalize the theory of Condon domains to the case of an
itinerant electron system undergoing a first-order metamagnetic transition. We
demonstrate that within a finite range of the applied field, dipolar
interactions induce a spatial modulation of the magnetization in the form of
stripes or bubbles. Our findings are consistent with recent observations in the
bilayer ruthenate SrRuO.Comment: 4 pages, 3 figures, minor changes, references adde
Modelling of hydrological response to climate change in glacierized Central Asian catchments
The arid lowlands of Central Asia are highly dependent on the water supplied by the Tien Shan mountains. Snow and ice storage make large contributions to current runoff, particularly in summer. Two runoff models with different temporal resolutions, HBV-ETH and OEZ, were applied in three glaciated catchments of the Tien Shan mountains. Scenario runs were produced for a climate change caused by the doubling of atmospheric CO2 as predicted by the GISS global circulation model and assuming a 50% reduction of glaciation extent, as well as a complete loss of glaciation. Agreement of the results was best for runs based on 50% glaciation loss, where both models predict an increase in spring and summer runoff compared to current levels. Scenarios for complete loss of glaciation predict an increase in spring runoff levels, followed by lower runoff levels for July and August. Model predictions differ concerning the degree of reduction of late summer runoff. These scenarios are sensitive to model simulation of basin precipitation, as well as to reduction of glaciation extent
Transverse momentum distributions and their forward- backward correlations in the percolating colour string approach
The forward-backward correlations in the distributions, which present a
clear signature of non-linear effects in particle production, are studied in
the model of percolating colour strings. Quantitative predictions are given for
these correlations at SPS, RHIC and LHC energies. Interaction of strings also
naturally explains the flattening of distributions and increase of
with energy and atomic number for nuclear collisionsComment: 6 pages in LaTex, 3 figures in Postscrip
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