3,473 research outputs found
Artifacts at 4.5 and 8.0 um in Short Wavelength Spectra from the Infrared Space Observatory
Spectra from the Short Wavelength Spectrometer (SWS) on ISO exhibit artifacts
at 4.5 and 8 um. These artifacts appear in spectra from a recent data release,
OLP 10.0, as spurious broad emission features in the spectra of stars earlier
than ~F0, such as alpha CMa. Comparison of absolutely calibrated spectra of
standard stars to corresponding spectra from the SWS reveals that these
artifacts result from an underestimation of the strength of the CO and SiO
molecular bands in the spectra of sources used as calibrators by the SWS.
Although OLP 10.0 was intended to be the final data release, these findings
have led to an additional release addressing this issue, OLP 10.1, which
corrects the artifacts.Comment: 14 pages, AASTex, including 5 figures. Accepted by ApJ Letter
A Cloudy/Xspec Interface
We discuss new functionality of the spectral simulation code CLOUDY which
allows the user to calculate grids with one or more initial parameters varied
and formats the predicted spectra in the standard FITS format. These files can
then be imported into the x-ray spectral analysis software XSPEC and used as
theoretical models for observations. We present and verify a test case.
Finally, we consider a few observations and discuss our results.Comment: 13 pages, 1 table, 4 figures, accepted for publication in PAS
Increased elastase sensitivity and decreased intramolecular interactions in the more transmissible 501Y.V1 and 501Y.V2 SARS-CoV-2 variants' spike protein-an in silico analysis.
Two SARS-CoV-2 variants of concern showing increased transmissibility relative to the Wuhan virus have recently been identified. Although neither variant appears to cause more severe illness nor increased risk of death, the faster spread of the virus is a major threat. Using computational tools, we found that the new SARS-CoV-2 variants may acquire an increased transmissibility by increasing the propensity of its spike protein to expose the receptor binding domain via proteolysis, perhaps by neutrophil elastase and/or via reduced intramolecular interactions that contribute to the stability of the closed conformation of spike protein. This information leads to the identification of potential treatments to avert the imminent threat of these more transmittable SARS-CoV-2 variants
Computing and Public Organizations
This survey of empirical research on computing in government updates a review that appeared ten years earlier in Public Administration Review. It focuses primarily on research related to the management of computing and on differences between public and private sector management of computing because the bulk of the new research and findings are here. The impacts of computing on employment, structure, worklife, decision making, organizational politics and constitutional issues are treated briefly because there is little new research or new findings. The paper concludes that while the use of computers in government at all levels of the federal system has increased greatly over the last decade, research on computing in government has declined precipitously
INSTITUTIONS AND THE INTERNATIONAL DIFFUSION OF INFORMATION TECHNOLOG
The production and use of information technology (IT) in developed countries is wcll established and growing at a rapid pace. Newly industrializing countries are adopting both IT production and use as national goals. Developing countries are beginning to formulate plans to do the same. The institutional role in the international diffusion of IT is not well understood, but it is clear from the literature on innovation that the institutional role is critical. The paper makes four points. First, a traditional and fairly rigorous way of thinking about innovations - the economic perspective deriving from Schumpeter and Hicks - has been shown by studies from economic history and sociology/communications of innovation to be inadequate for explaining the dynamics of innovative change. The missing element is understanding of differential roles played by institutions. Second, among those promoting the need for institutional intervention there has been a debate about whether innovation is primarily supply-pushed or demand-pulled. The answer to the question has important institutional implications. The evidence, again mostly from economic history, shows it to be both, in iterative fashion. Thus institutions can intervene meaningfully on both sides. Third, there are two major forms of institutional intervention: influence and regulation. The possible intervention actions of institutions can be encompassed by a 2 x 2 matrix with supply-push and demand-pull on one dimension and influence and regulation on the other. Finally, if government wants to intervene, there are six classes of roles that might be pursued to affect innovation
Isomer shift and magnetic moment of the long-lived 1/2 isomer in Zn: signature of shape coexistence near Ni
Collinear laser spectroscopy has been performed on the Zn
isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred
milliseconds half-life was confirmed, and the nuclear spins and moments of the
ground and isomeric states in Zn as well as the isomer shift were
measured. From the observed hyperfine structures, spins and
are firmly assigned to the ground and isomeric states. The magnetic moment
(Zn) = 1.1866(10) , confirms the spin-parity
with a shell-model configuration, in excellent
agreement with the prediction from large scale shell-model theories. The
magnetic moment (Zn) = 1.0180(12) supports a
positive parity for the isomer, with a wave function dominated by a 2h-1p
neutron excitation across the shell gap. The large isomer shift
reveals an increase of the intruder isomer mean square charge radius with
respect to that of the ground state:
= +0.204(6) fm, providing first evidence of shape coexistence.Comment: 5 pages, 4 figures, 1 table, Accepeted by Phys. Rev. Lett. (2016
Spatially Resolved Outflows in a Seyfert Galaxy at z = 2.39
We present the first spatially resolved analysis of rest-frame optical and UV
imaging and spectroscopy for a lensed galaxy at z = 2.39 hosting a Seyfert
active galactic nucleus (AGN). Proximity to a natural guide star has enabled
high signal-to-noise VLT SINFONI + adaptive optics observations of rest-frame
optical diagnostic emission lines, which exhibit an underlying broad component
with FWHM ~ 700 km/s in both the Balmer and forbidden lines. Measured line
ratios place the outflow robustly in the region of the ionization diagnostic
diagrams associated with AGN. This unique opportunity - combining gravitational
lensing, AO guiding, redshift, and AGN activity - allows for a magnified view
of two main tracers of the physical conditions and structure of the
interstellar medium in a star-forming galaxy hosting a weak AGN at cosmic noon.
By analyzing the spatial extent and morphology of the Ly-alpha and
dust-corrected H-alpha emission, disentangling the effects of star formation
and AGN ionization on each tracer, and comparing the AGN induced mass outflow
rate to the host star formation rate, we find that the AGN does not
significantly impact the star formation within its host galaxy.Comment: 16 pages, 5 figures, accepted for publication in Ap
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A unified and automated approach to attractor reconstruction
We present a fully automated method for the optimal state space reconstruction from univariate and multivariate time series. The proposed methodology generalizes the time delay embedding procedure by unifying two promising ideas in a symbiotic fashion. Using non-uniform delays allows the successful reconstruction of systems inheriting different time scales. In contrast to the established methods, the minimization of an appropriate cost function determines the embedding dimension without using a threshold parameter. Moreover, the method is capable of detecting stochastic time series and, thus, can handle noise contaminated input without adjusting parameters. The superiority of the proposed method is shown on some paradigmatic models and experimental data from chaotic chemical oscillators
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