422 research outputs found
Insurance - Rate Regulation - Competitors\u27 Standing to Seek Administrative Review of Rate Filings
The purpose of this comment is to explore, in the light of the All-Industry pattern of regulation and the applicable public policy considerations, the right of rating bureaus and their members to such standing at the administrative level
A Two Hour Quasi-Period in an Ultra-luminous X-Ray source in NGC628
Quasi-periodic oscillations and X-ray spectroscopy are powerful probes of
black hole masses and accretion disks, and here we apply these diagnostics to
an ultraluminous X-ray source (ULX) in the spiral galaxy NGC628 (M74). This
object was observed four times over two years with the Chandra X-ray
Observatory and XMM-Newton, with three long observations showing dramatic
variability, distinguished by a series of outbursts with a quasi-period (QPO)
of 4,000-7,000 seconds. This is unique behavior among both ULXs and Galactic
X-ray binaries due to the combination of its burst-like peaks and deep troughs,
its long quasi-periods, its high variation amplitudes of %, and its
substantial variability between observations. The X-ray spectra is fitted by an
absorbed accretion disk plus a power-law component, suggesting the ULX was in a
spectral state analogous to the Low Hard state or the Very High state of
Galactic black hole X-ray binaries. A black hole mass of -- is estimated from the -- scaling relation found in the
Galactic X-ray binaries and active galactic nuclei.Comment: 12 pages, 3 figures. accepted for publication in ApJ Lette
South Asian monsoon history over the past 60 kyr recorded by radiogenic isotopes and clay mineral assemblages in the Andaman Sea
The Late Quaternary variability of the South Asian (or Indian) monsoon has been linked with glacial‐interglacial and millennial scale climatic changes but past rainfall intensity in the river catchments draining into the Andaman Sea remains poorly constrained. Here we use radiogenic Sr, Nd, and Pb isotope compositions of the detrital clay‐size fraction and clay mineral assemblages obtained from sediment core NGHP Site 17 in the Andaman Sea to reconstruct the variability of the South Asian monsoon during the past 60 kyr. Over this time interval εNd values changed little, generally oscillating between −7.3 and −5.3 and the Pb isotope signatures are essentially invariable, which is in contrast to a record located further northeast in the Andaman Sea. This indicates that the source of the detrital clays did not change significantly during the last glacial and deglaciation suggesting the monsoon was spatially stable. The most likely source region is the Irrawaddy river catchment including the Indo‐Burman Ranges with a possible minor contribution from the Andaman Islands. High smectite/(illite + chlorite) ratios (up to 14), as well as low 87Sr/86Sr ratios (0.711) for the Holocene period indicate enhanced chemical weathering and a stronger South Asian monsoon compared to marine oxygen isotope stages 2 and 3. Short, smectite‐poor intervals exhibit markedly radiogenic Sr isotope compositions and document weakening of the South Asian monsoon, which may have been linked to short‐term northern Atlantic climate variability on millennial time scales
Molecular dynamics of flows in the Knudsen regime
Novel technological applications often involve fluid flows in the Knudsen
regime in which the mean free path is comparable to the system size. We use
molecular dynamics simulations to study the transition between the dilute gas
and the dense fluid regimes as the fluid density is increased.Comment: REVTeX, 15 pages, 4 EPS figures, to appear in Physica
RFI Risk Reduction Activities Using New Goddard Digital Radiometry Capabilities
The Goddard Radio-Frequency Explorer (GREX) is the latest fast-sampling radiometer digital back-end processor that will be used for radiometry and radio-frequency interference (RFI) surveying at Goddard Space Flight Center. The system is compact and deployable, with a mass of about 40 kilograms. It is intended to be flown on aircraft. GREX is compatible with almost any aircraft, including P-3, twin otter, C-23, C-130, G3, and G5 types. At a minimum, the system can function as a clone of the Soil Moisture Active Passive (SMAP) ground-based development unit [1], or can be a completely independent system that is interfaced to any radiometer, provided that frequency shifting to GREX's intermediate frequency is performed prior to sampling. If the radiometer RF is less than 200MHz, then the band can be sampled and acquired directly by the system. A key feature of GREX is its ability to simultaneously sample two polarization channels simultaneously at up to 400MSPS, 14-bit resolution each. The sampled signals can be recorded continuously to a 23 TB solid-state RAID storage array. Data captures can be analyzed offline using the supercomputing facilities at Goddard Space Flight Center. In addition, various Field Programmable Gate Array (FPGA) - amenable radiometer signal processing and RFI detection algorithms can be implemented directly on the GREX system because it includes a high-capacity Xilinx Virtex-5 FPGA prototyping system that is user customizable
Ariel - Volume 9 Number 4
Executive Editor
Emily Wofford
Business Manager
Fredric Jay Matlin
University News
John Patrick Welch
World News
George Robert Coar
Editorials Editor
Steve Levine
Features
Mark Rubin
Brad Feldstein
Sports Editor
EIi Saleeby
Circulation
Victor Onufreiczuk
Lee Wugofski
Graphics and Art
Steve Hulkower
Commons Editor
Brenda Peterso
Ariel - Volume 9 Number 3
Executive Editor
Emily Wofford
Business Manager
Fredric Jay Matlin
University News
John Patrick Welch
World News
George Robert Coar
Editorials Editor
Steve Levine
Features
Mark Rubin
Brad Feldstein
Photo
Rick Spaide
Circulation
Victor Onufreiczuk
Lee Wugofski
Graphics and Art
Steve Hulkower
Commons Editor
Brenda Peterso
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