2,655 research outputs found
MS 063 Guide to Walter J. Russell, MD, DM Sc. Papers (1884)
Walter J. Russell donated the material in this collection in 1986, 1989, and 1995. Dr. Russell received his Doctor of Medicine degree at the St. Louis University Medical School, in 1952. In July of 1959, he was appointed Chief of the Department of Radiology of the Atomic Bomb Casualty Commission. Dr. Russell continued his to conduct his research with the ABCC successor organization, the Radiation Effects Research Foundation. See more at MS 063
Panchromatic Imaging of a Transitional Disk: The Disk of GM Aur in Optical and FUV Scattered Light
We have imaged GM Aur with HST, detected its disk in scattered light at 1400A
and 1650A, and compared these with observations at 3300A, 5550A, 1.1 microns,
and 1.6 microns. The scattered light increases at shorter wavelengths. The
radial surface brightness profile at 3300A shows no evidence of the 24AU radius
cavity that has been previously observed in sub-mm observations. Comparison
with dust grain opacity models indicates the surface of the entire disk is
populated with sub-micron grains. We have compiled an SED from 0.1 microns to 1
mm, and used it to constrain a model of the star+disk system that includes the
sub-mm cavity using the Monte Carlo Radiative Transfer code by Barbara Whitney.
The best-fit model image indicates that the cavity should be detectable in the
F330W bandpass if the cavity has been cleared of both large and small dust
grains, but we do not detect it. The lack of an observed cavity can be
explained by the presence of sub-microns grains interior to the sub-mm cavity
wall. We suggest one explanation for this which could be due to a planet of
mass <9 Jupiter masses interior to 24 AU. A unique cylindrical structure is
detected in the FUV data from the Advanced Camera for Surveys/Solar Blind
Channel. It is aligned along the system semi-minor axis, but does not resemble
an accretion-driven jet. The structure is limb-brightened and extends 190 +/-
35 AU above the disk midplane. The inner radius of the limb-brightening is 40
+/- 10 AU, just beyond the sub-millimeter cavity wall.Comment: 40 pages, 11 figures, 4 tables, accepted to Ap
Blockwise Key Distillation in Satellite-based Quantum Key Distribution
Free-space satellite communication has significantly lower photon loss than
terrestrial communication via optical fibers. Satellite-based quantum key
distribution (QKD) leverages this advantage and provides a promising direction
in achieving long-distance inter-continental QKD. Satellite channels, however,
can be highly dynamic due to various environmental factors and time-of-the-day
effects, leading to heterogeneous noises over time. In this paper, we compare
two key distillation techniques for satellite-based QKD. One is the traditional
{\em non-blockwise} strategy that treats all the signals as a whole; the other
is a {\em blockwise} strategy that divides the signals into individual blocks
that have similar noise characteristics and processes them independently.
Through extensive simulation in a wide range of settings, we show trends in
optimal parameter choices and when one strategy provides better key generation
rates than the other. Our results show that the blockwise strategy can lead to
up to key rate improvement (leading to on average more
key bits per day) when considering two types of blocks, i.e., for nighttime and
daytime, respectively. The blockwise strategy only requires changes in the
classical post-processing stage of QKD and can be easily deployed in existing
satellite systems
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