7,173 research outputs found
Scaling Up: Bringing the Transitional Care Model Into the Mainstream
Describes features of an innovative care management intervention to facilitate elderly, chronically ill patients' transitions among providers and settings; the adopting organization; and the external environment that affect its translation into practice
Low Mass Stars and Brown Dwarfs around Sigma Orionis
We present optical spectroscopy of 71 photometric candidate low-mass members
of the cluster associated with Sigma Orionis. Thirty-five of these are found to
pass the lithium test and hence are confirmed as true cluster members, covering
a mass range of <0.055-0.3M_{sun}, assuming a mean cluster age of <5 Myr. We
find evidence for an age spread on the (I, I-J) colour magnitude diagram,
members appearing to lie in the range 1-7 Myr. There are, however, a
significant fraction of candidates that are non-members, including some
previously identified as members based on photometry alone. We see some
evidence that the ratio of spectroscopically confirmed members to photometric
candidates decreases with brightness and mass. This highlights the importance
of spectroscopy in determining the true initial mass-function.Comment: To appear in the 12th Cambridge Workshop on Cool Stars Stellar
Systems and the Su
Fourier Transform Spectroscopy of the submillimetre continuum emission from hot molecular cores
We have used a Fourier Transform Spectrometer on the James Clerk Maxwell
Telescope to study the submillimetre continuum emission from dust in three hot
molecular cores (HMC). The spectral index beta of the dust emission for these
sources has been determined solely within the 30 GHz wide 350 GHz (850 micron)
passband to an accuracy comparable to those determined through multi-wavelength
observations. We find an average beta = 1.6, in agreement with spectral indices
determined from previous submillimetre observations of these sources and with
those determined for HMC in general. The largest single source of uncertainty
in these results is the variability of the atmosphere at 350 GHz, and with
better sky subtraction techniques we show that the dust spectral index can
clearly be determined within one passband to high accuracy with a submillimetre
FTS. Using an imaging FTS on SCUBA-2, the next generation wide-field
submillimetre camera currently under development to replace SCUBA at the JCMT
in 2006, we calculate that at 350 GHz it will be possible to determine beta to
+/- 0.1 for sources as faint as 400 mJy/beam and to +/- 0.3 for sources as
faint as 140 mJy/beam.Comment: 11 pages, 5 figures, accepted for publication in MNRA
The ``Outside-In'' Outburst of HT Cassiopeiae
We present results from photometric observations of the dwarf nova system HT
Cas during the eruption of November 1995. The data include the first
two--colour observations of an eclipse on the rise to outburst. They show that
during the rise to outburst the disc deviates significantly from steady state
models, but the inclusion of an inner-disc truncation radius of about 4
and a ``flared'' disc of semi-opening angle of produces
acceptable fits. The disc is found to have expanded at the start of the
outburst to about , as compared to quiescent measurements. The
accretion disc then gradually decreases in radius reaching during
the last stages of the eruption. Quiescent eclipses were also observed prior to
and after the eruption and a revised ephemeris is calculated.Comment: 9 pages, 11 figures, to appear in MNRA
Gas signatures of Herbig Ae/Be disks probed with Herschel SPIRE spectroscopy
Herbig Ae/Be objects, like their lower mass counterparts T Tauri stars, are
seen to form a stable circumstellar disk which is initially gas-rich and could
ultimately form a planetary system. We present Herschel SPIRE 460-1540 GHz
spectra of five targets out of a sample of 13 young disk sources, showing line
detections mainly due to warm CO gas.Comment: to be published in proceedings of IAU symposium 299 (Victoria, BC,
Canada, June 2013
Reconnection in Marginally Collisionless Accretion Disk Coronae
We point out that a conventional construction placed upon observations of
accreting black holes, in which their nonthermal X-ray spectra are produced by
inverse comptonization in a coronal plasma, suggests that the plasma is
marginally collisionless. Recent developments in plasma physics indicate that
fast reconnection takes place only in collisionless plasmas. As has recently
been suggested for the Sun's corona, such marginal states may result from a
combination of energy balance and the requirements of fast magnetic
reconnection.Comment: Revised in response to referee. Accepted ApJ. 11 pp., no figures.
Uses aastex 5.0
Noise Robust Blind System Identification Algorithms Based On A Rayleigh Quotient Cost Function
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