1,508 research outputs found
Global well-posedness for KdV in Sobolev Spaces of negative index
The initial value problem for the Korteweg-deVries equation on the line is
shown to be globally well-posed for rough data. In particular, we show global
well-posedness for initial data in H^s({\mathbb{R}), -3/10<s.Comment: 5 pages. Electronic Journal of Differential equations (submitted
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First Case of Systemic Coronavirus Infection in a Domestic Ferret (Mustela putorius furo) in Peru.
A domestic ferret from Lima, Peru, died after ten days of non-specific clinical signs. Based on pathology, immunohistochemistry and molecular analysis, ferret systemic coronavirus (FRSCV)-associated disease was diagnosed for the first time in South America. This report highlights the potential spread of pathogens by the international pet trade
Seeing Galaxies Through Thick & Thin. III. HST Imaging of the Dust in Backlit Spiral Galaxies
We present analysis of WFPC2 imaging of two spiral galaxies partially backlit
by E/S0 systems in the pairs AM1316-241 and AM0500-620, and the spiral
foreground system in NGC 1275. Images in B and I are used to determine the
reddening curve of in these systems. The spiral component of AM1316-241 shows
dust strongly concentrated in discrete arms, with a reddening law very close to
the Milky Way mean. The dust distribution is scale-free between about 100 pc
and the arm scale. The spiral in AM0500-620 shows dust concentrated in arms and
interarm spurs, with measurable interarm extinction as well. Although its dust
properties are less well-determined, we find evidence for a steeper extinction
law here. The shape of the reddening law suggests that, at least in AM1316-241,
we have resolved most of the dust structure. In AM0500-620, the slope of the
fractal perimeter-scale relation steepens systematically from low to high
extinction. In AM1316-241, we cannot determine a unique fractal dimension from
the defining area-perimeter relation, so the projected dust distribution is
best defined as fractal-like. In neither galaxy do we see regions even on
single-pixel scales in spiral arms with AB > 2.5. The measurements in NGC 1275
are compromised by our lack of independent knowledge of the foreground system's
light distribution, but masked sampling of the absorption suggests an effective
reddening curve much flatter than the Milky Way mean (perhaps indicating that
the foreground system has been affected by immersion in the hot intracluster
gas).Comment: Astronomical Journal, in press. 13 figures. Full-size PostScript
figures available at http://www.astr.ua.edu/preprints/kee
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