4,179 research outputs found
Herschel/HIFI observations of IRC+10216: water vapor in the inner envelope of a carbon-rich AGB star
We report the results of observations of ten rotational transitions of water
vapor toward the carbon-rich AGB (asymptotic giant branch) star IRC+10216 (CW
Leonis), carried out with Herschel's HIFI instrument. Each transition was
securely detected by means of observations using the dual beam switch mode of
HIFI. The measured line ratios imply that water vapor is present in the inner
outflow at small distances (few x 1.E+14 cm) from the star, confirming recent
results reported by Decin et al. from observations with Herschel's PACS and
SPIRE instruments. This finding definitively rules out the hypothesis that the
observed water results from the vaporization of small icy objects in circular
orbits. The origin of water within the dense C-rich envelope of IRC+10216
remains poorly understood. We derive upper limits on the H2-17O/H2-16O and
H2-18O/H2-16O isotopic abundance ratios of ~ 5.E-3 (3 sigma), providing
additional constraints on models for the origin of the water vapor in
IRC+10216.Comment: Accepted for publication in the Astrophysical Journal Letter
Investigating the relationship between social support and durable return to work
The aim of the current study was to investigate the relationship between social support and durable return to work (RTW) post occupational injury. A total of 1,179 questionnaires were posted to clients previously receiving vocational rehabilitation services from the Return to Work Assist program in Queensland, Australia. Participants were asked to indicate their current RTW status, in addition to completing questionnaires measuring their relationship with their superior, relationships with colleagues, and social support external to the workplace. The statistical analysis included 110 participants. An ANOVA indicated that participants in the RTW group reported significantly better relationships with their superiors and colleagues than participants in the non-durable RTW group. No significant differences were observed between the RTW, non-durable RTW and no RTW groups on a measure of social support external to the workplace. Although the findings were limited by the low response rate, an evaluation of demographics indicated the respondents were representative of the original target sample. The findings suggested that providing support in the workplace is an important area for intervention and may be a means of increasing durable RTW outcomes.</jats:p
Public Health Adaptation to Climate Change in Canadian Jurisdictions
Climate change poses numerous risks to the health of Canadians. Extreme weather events, poor air quality, and food insecurity in northern regions are likely to increase along with the increasing incidence and range of infectious diseases. In this study we identify and characterize Canadian federal, provincial, territorial and municipal adaptation to these health risks based on publically available information. Federal health adaptation initiatives emphasize capacity building and gathering information to address general health, infectious disease and heat-related risks. Provincial and territorial adaptation is varied. Quebec is a leader in climate change adaptation, having a notably higher number of adaptation initiatives reported, addressing almost all risks posed by climate change in the province, and having implemented various adaptation types. Meanwhile, all other Canadian provinces and territories are in the early stages of health adaptation. Based on publically available information, reported adaptation also varies greatly by municipality. The six sampled Canadian regional health authorities (or equivalent) are not reporting any adaptation initiatives. We also find little relationship between the number of initiatives reported in the six sampled municipalities and their provinces, suggesting that municipalities are adapting (or not adapting) autonomously
Planet-Planet Scattering Alone Cannot Explain the Free-Floating Planet Population
Recent gravitational microlensing observations predict a vast population of
free-floating giant planets that outnumbers main sequence stars almost twofold.
A frequently-invoked mechanism for generating this population is a dynamical
instability that incites planet-planet scattering and the ejection of one or
more planets in isolated main sequence planetary systems. Here, we demonstrate
that this process alone probably cannot represent the sole source of these
galactic wanderers. By using straightforward quantitative arguments and N-body
simulations, we argue that the observed number of exoplanets exceeds the
plausible number of ejected planets per system from scattering. Thus, other
potential sources of free-floaters, such as planetary stripping in stellar
clusters and post-main-sequence ejection, must be considered.Comment: 6 pages, 2 figures, accepted for publication in MNRAS Letter
A Database of Cepheid Distance Moduli and TRGB, GCLF, PNLF and SBF Data Useful for Distance Determinations
We present a compilation of Cepheid distance moduli and data for four
secondary distance indicators that employ stars in the old stellar populations:
the planetary nebula luminosity function (PNLF), the globular cluster
luminosity function (GCLF), the tip of the red giant branch (TRGB), and the
surface brightness fluctuation (SBF) method. The database includes all data
published as of July 15, 1999. The main strength of this compilation resides in
all data being on a consistent and homogeneous system: all Cepheid distances
are derived using the same calibration of the period-luminosity relation, the
treatment of errors is consistent for all indicators, measurements which are
not considered reliable are excluded. As such, the database is ideal for
inter-comparing any of the distance indicators considered, or for deriving a
Cepheid calibration to any secondary distance indicator. Specifically, the
database includes: 1) Cepheid distances, extinctions and metallicities; 2)
apparent magnitudes of the PNLF cutoff; 3) apparent magnitudes and colors of
the turnover of the GCLF (both in the V- and B-bands); 4) apparent magnitudes
of the TRGB (in the I-band) and V-I colors at and 0.5 magnitudes fainter than
the TRGB; 5) apparent surface brightness fluctuation magnitudes I, K', K_short,
and using the F814W filter with the HST/WFPC2. In addition, for every galaxy in
the database we give reddening estimates from DIRBE/IRAS as well as HI maps,
J2000 coordinates, Hubble and T-type morphological classification, apparent
total magnitude in B, and systemic velocity. (Abridged)Comment: Accepted for publication in the Astrophysical Journal Supplement
Series. Because of space limitations, the figures included are low resolution
bitmap images. Original figures can be found at
http://www.astro.ucla.edu/~laura/pub.ht
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