5,433 research outputs found
Entropy Distance: New Quantum Phenomena
We study a curve of Gibbsian families of complex 3x3-matrices and point out
new features, absent in commutative finite-dimensional algebras: a
discontinuous maximum-entropy inference, a discontinuous entropy distance and
non-exposed faces of the mean value set. We analyze these problems from various
aspects including convex geometry, topology and information geometry. This
research is motivated by a theory of info-max principles, where we contribute
by computing first order optimality conditions of the entropy distance.Comment: 34 pages, 5 figure
Striking an Imbalance: The Interpretation of Section 21D(b)(2) of the Securities Exchange Act of 1934 in Silicon Graphics
SN2002kg -- the brightening of LBV V37 in NGC 2403
SN2002kg is a type IIn supernova, detected in October 2002 in the nearby
spiral galaxy NGC 2403. We show that the position of SN2002kg agrees within the
errors with the position of the LBV V37. Ground based and HST ACS images
however show that V37 is still present after the SN2002kg event. We compiled a
lightcurve of V37 which underlines the variablity of the object, and shows that
SN2002kg was the brightening of V37 and not a supernova. The recent brightening
is not a giant eruption, but more likely part of an S Dor phase. V37 shows
strong Halpha +[NII] emission in recent images and in the SN2002kg spectrum,
which we interprete as the signature of the presence of an LBV nebula. A
historic spectrum lacks emission, which may hint that we are witnessing the
formation of an LBV nebula.Comment: 4 pages, 5 figures, accepted in A&A Letter, paper with images in full
resolution at http://www.astro.ruhr-uni-bochum.de/kweis/publications.htm
Rb*He_n exciplexes in solid 4_He
We report the observation of emission spectra from Rb*He_n exciplexes in
solid 4He. Two different excitation channels were experimentally identified,
viz., exciplex formation via laser excitation to the atomic 5P3/2 and to the
5P1/2 levels. While the former channel was observed before in liquid helium, on
helium nanodroplets and in helium gas by different groups, the latter creation
mechanism occurs only in solid helium or in gaseous helium above 10 Kelvin. The
experimental results are compared to theoretical predictions based on the
extension of a model, used earlier by us for the description of Cs*He_n
exciplexes. We also report the first observation of fluorescence from atomic
rubidium in solid helium, and discuss striking differences between the
spectroscopic feature of Rb-He and Cs-He systems.Comment: 8 pages, 8 figure
Mapping Residual Structure in Disordered Protein Ensembles with Millisecond H/D Exchange Mass Spectrometry
The Historical Geography of Rail and Highway Transport at Bemidji, Minnesota
This thesis studies the geographic reasons for the development of transportation at Bemidji, Minnesota. The transportation types studied are railroads, trucking and busses.
The physical setting is examined to determine the basic reasons for settlement of the area. Physical aspects examined are the geology, soils, climate, and watersheds. Rural land use and reasons for the choice of the city site are also studied.
In the presentation of railroad development, five railroads are studied geographically. These include the Red Lake Transportation Company; Wilton and Northern Railroad; Brainerd and Northern Railway Company; Great Northern Railway; and the Minneapolis, St. Paul and Sault Ste. Marie Railroad.
Development of trunk highways through Bemidji is examined in the section on highway transport development. In addition, the geographical reasons for the historical development of dray lines, common carriers, contract carriers, long distance trucking, and busses are studied.
The major changes that have occurred in each type of transportation are analyzed. Included in this analysis are possible future developments of the three major forms of transportation
Outflow or galactic wind: The fate of ionized gas in the halos of dwarf galaxies
Context: H\alpha images of star bursting irregular galaxies reveal a large
amount of extended ionized gas structures, in some cases at kpc-distance away
from any place of current star forming activity. A kinematic analysis of
especially the faint structures in the halo of dwarf galaxies allows insights
into the properties and the origin of this gas component. This is important for
the chemical evolution of galaxies, the enrichment of the intergalactic medium,
and for the understanding of the formation of galaxies in the early universe.
Aims: We want to investigate whether the ionized gas detected in two
irregular dwarf galaxies (NGC 2366 and NGC 4861) stays gravitationally bound to
the host galaxy or can escape from it by becoming a freely flowing wind.
Methods: Very deep H\alpha images of NGC 2366 and NGC 4861 were obtained to
detect and catalog both small and large scale ionized gas structures down to
very low surface brightnesses. Subsequently, high-resolution long-slit echelle
spectroscopy of the H\alpha line was performed for a detailed kinematic
analysis of the most prominent filaments and shells. To calculate the escape
velocity of both galaxies and to compare it with the derived expansion
velocities of the detected filaments and shells, we used dark matter halo
models.
Results: We detected a huge amount of both small scale (up to a few hundred
pc) and large scale (about 1-2 kpc of diameter or length) ionized gas
structures on our H\alpha images. Many of the fainter ones are new detections.
The echelle spectra reveal outflows and expanding bubbles/shells with
velocities between 20 and 110 km/s. Several of these structures are in
accordance with filaments in the H\alpha images. A comparison with the escape
velocities of the galaxies derived from the NFW dark matter halo model shows
that all gas features stay gravitationally bound.Comment: 15 pages, 13 figures, accepted for publication in A&
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