28,590 research outputs found
Ionospheric and magnetospheric plasmapauses'
During August 1972, Explorer 45 orbiting near the equatorial plane with an apogee of about 5.2 R sub e traversed magnetic field lines in close proximity to those simultaneously traversed by the topside ionospheric satellite ISIS 2 near dusk in the L range 2-5.4. The locations of the Explorer 45 plasmapause crossings during this month were compared to the latitudinal decreases of the H(+) density observed on ISIS 2 near the same magnetic field lines. The equatorially determined plasmapause field lines typically passed through or poleward of the minimum of the ionospheric light ion trough, with coincident satellite passes occurring for which the L separation between the plasmapause and trough field lines was between 1 and 2. Vertical flows of the H(+) ions in the light ion trough as detected by the magnetic ion mass spectrometer on ISIS were directed upward with velocities between 1 and 2 kilometers/sec near dusk on these passes. These velocities decreased to lower values on the low latitude side of the H(+) trough but did not show any noticeable change across the field lines corresponding to the magnetospheric plasmapause
Image-based Recommendations on Styles and Substitutes
Humans inevitably develop a sense of the relationships between objects, some
of which are based on their appearance. Some pairs of objects might be seen as
being alternatives to each other (such as two pairs of jeans), while others may
be seen as being complementary (such as a pair of jeans and a matching shirt).
This information guides many of the choices that people make, from buying
clothes to their interactions with each other. We seek here to model this human
sense of the relationships between objects based on their appearance. Our
approach is not based on fine-grained modeling of user annotations but rather
on capturing the largest dataset possible and developing a scalable method for
uncovering human notions of the visual relationships within. We cast this as a
network inference problem defined on graphs of related images, and provide a
large-scale dataset for the training and evaluation of the same. The system we
develop is capable of recommending which clothes and accessories will go well
together (and which will not), amongst a host of other applications.Comment: 11 pages, 10 figures, SIGIR 201
Effect of environment on biological burden during spacecraft assembly
Determining effects of environment on accumulation of biological burden on spacecraft during assembl
Short-time dynamics of finite-size mean-field systems
We study the short-time dynamics of a mean-field model with non-conserved
order parameter (Curie-Weiss with Glauber dynamics) by solving the associated
Fokker-Planck equation. We obtain closed-form expressions for the first moments
of the order parameter, near to both the critical and spinodal points, starting
from different initial conditions. This allows us to confirm the validity of
the short-time dynamical scaling hypothesis in both cases. Although the
procedure is illustrated for a particular mean-field model, our results can be
straightforwardly extended to generic models with a single order parameter.Comment: accepted for publication in JSTA
Charge Modulations in the Superconducting State of the Cuprates
Motivated by the recent scanning tunneling microscopy (STM) and neutron
scattering experiments, we investigate various charge density wave orders
coexisting with superconductivity in the cuprate superconductors. The explicit
expressions of the local density of states and its Fourier component at the
ordering wavevector for the weak charge modulations are derived. It is shown
that the STM experiments in cannot be explained by
a site- or bond-centered charge modulation alone, but agree well with the
presence of the dimerization hopping and transverse pairing modulations. We
also calculate the spectral function for the charged stripes, which is measured
by the ARPES experiments.Comment: 3 pages with 4 figures. To be published in PR
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Data assimilation insights on selecting the most valuable atmospheric measurements
We discuss how objective guidance on selecting the most valuable atmospheric measurements on future Mars spacecraft missions can be provided through already developed Martian atmospheric data assimilation systems, and in particular through Observing System Simulation Experiments (OSSEs) which are widely used to design instruments for the Earth’s atmosphere
Signature of Spin Collective Mode in Local Tunneling Spectra of a d-wave Superconductor
We consider the influence of magnetic excitations on the local density of
states in the d-wave superconductor. The magnetic susceptibility is calculated
within the renormalized model and its influence on the quasiparticle
self-energy is considered using a minimal model originally proposed by
Polkovnikov {\it et al.}[cond-mat/0203176]. We find the local density of states
possess periodic components both along and directions
with the associated wavevectors changing in magnitude as the quasiparticle
energy is varied. Comparison with the STM experiment reveals that the
calculated LDOS modulation is inconsistent with the measured data.Comment: Two figures separately attached as .jpg file
Weak Charge-Changing Flow in Expanding r-Process Environments
We assess the prospects for attaining steady nuclear flow equilibrium in
expanding r-process environments where beta decay and/or neutrino capture
determine the nuclear charge-changing rates. For very rapid expansions, we find
that weak steady flow equilibrium normally cannot be attained. However, even
when neutron capture processes freeze out in such nonequilibrium conditions,
abundance ratios of nuclear species in the r-process peaks might still mimic
those attained in weak steady flow. This result suggests that the r-process
yield in a regime of rapid expansion can be calculated reliably only when all
neutron capture, photodisintegration, and weak interaction processes are fully
coupled in a dynamical calculation. We discuss the implications of these
results for models of the r-process sited in rapidly expanding neutrino-heated
ejecta.Comment: 21 pages, AAS LaTex, 2 postscript figure
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