4,229 research outputs found
Is the Scottish population living dangerously? Prevalence of multiple risk factors: the Scottish Health Survey 2003
<b>Background:</b>
Risk factors are often considered individually, we aimed to investigate the prevalence of combinations of multiple behavioural risk factors and their association with socioeconomic determinants.<p></p>
<b>Methods:</b>
Multinomial logistic regression was used to model the associations between socioeconomic factors and multiple risk factors from data in the Scottish Health Survey 2003. Prevalence of five main behavioural risk factors - smoking alcohol, diet, overweight/obesity, and physical inactivity, and the odds in relation to demographic, individual and area socioeconomic factors.<p></p>
<b>Results:</b>
Full data were available on 6,574 subjects (80.7% of the survey sample). Nearly the whole adult population (97.5%) reported to have at least one behavioural risk factor; while 55% have three or more risk factors; and nearly 20% have four or all five risk factors. The most important determinants for having four or five multiple risk factors were low educational attainment which conferred around a 3-fold increased odds compared to high education; and residence in the most deprived communities (relative to least deprived) which had greater than 3-fold increased odds.<p></p>
<b>Conclusions:</b>
The prevalence of multiple behavioural risk factors was high and the prevalence of absence of all risk factors very low. These behavioural patterns were socioeconomically determined. Policy to address factors needs to be joined up and better consider underlying socioeconomic circumstances.<p></p>
PG 1700+518 Revisited: Adaptive Optics Imaging and a Revised Starburst Age for the Companion
We present the results of adaptive-optics imaging of the z=0.2923 QSO PG
1700+518 in the J and H bands. The extension to the north of the QSO is clearly
seen to be a discrete companion with a well-defined tidal tail, rather than a
feature associated with the host galaxy of PG 1700+518 itself. On the other
hand, an extension to the southwest of the QSO (seen best in deeper, but
lower-resolution, optical images) does likely comprise tidal material from the
host galaxy. The SED derived from images in J, H, and two non-standard optical
bands indicates the presence of dust intermixed with the stellar component. We
use our previously reported Keck spectrum of the companion, the SED found from
the imaging data, and updated spectral-synthesis models to constrain the
stellar populations in the companion and to redetermine the age of the
starburst. While our best-fit age of 0.085 Gyr is nearly the same as our
earlier determination, the fit of the new models is considerably better. This
age is found to be remarkably robust with respect to different assumptions
about the nature of the older stellar component and the effects of dust.Comment: 11 pages; includes two eps figures. Latex (AASTEX). Two additional
figures in gif format. Postscript version including all figs. (424 kb) can be
obtained from http://www.ifa.hawaii.edu/~canaguby/preprints.html To appear in
ApJ. Letter
Risk of cancer following primary total hip replacement or primary resurfacing arthroplasty of the hip : A retrospective cohort study in Scotland
Acknowledgements: We are grateful to Lee Barnsdale, Doug Clark, and Richard Dobbie for advice and assistance with data preparation before analysis, and to the three anonymous referees for their helpful comments and suggestions.Peer reviewedPublisher PD
Lithium in the prevention of suicide in mood disorders: updated systematic review and meta-analysis
Objective To assess whether lithium has a specific preventive effect for suicide and self harm in people with unipolar and bipolar mood disorders. Design Systematic review and meta-analysis. Data sources Medline, Embase, CINAHL, PsycINFO, CENTRAL, web based clinical trial registries, major textbooks, authors of important papers and other experts in the discipline, and websites of pharmaceutical companies that manufacture lithium or the comparator drugs (up to January 2013). Inclusion criteria Randomised controlled trials comparing lithium with placebo or active drugs in long term treatment for mood disorders. Review methods Two reviewers assessed studies for inclusion and risk of bias and extracted data. The main outcomes were the number of people who completed suicide, engaged in deliberate self harm, and died from any cause. Results 48 randomised controlled trials (6674 participants, 15 comparisons) were included. Lithium was more effective than placebo in reducing the number of suicides (odds ratio 0.13, 95% confidence interval 0.03 to 0.66) and deaths from any cause (0.38, 0.15 to 0.95). No clear benefits were observed for lithium compared with placebo in preventing deliberate self harm (0.60, 0.27 to 1.32). In unipolar depression, lithium was associated with a reduced risk of suicide (0.36, 0.13 to 0.98) and also the number of total deaths (0.13, 0.02 to 0.76) compared with placebo. When lithium was compared with each active individual treatment a statistically significant difference was found only with carbamazepine for deliberate self harm. Lithium tended to be generally better than the other active comparators, with small statistical variation between the results. Conclusions Lithium is an effective treatment for reducing the risk of suicide in people with mood disorders. Lithium may exert its antisuicidal effects by reducing relapse of mood disorder, but additional mechanisms should also be considered because there is some evidence that lithium decreases aggression and possibly impulsivity, which might be another mechanism mediating the antisuicidal effect
The Nature of Optical Features in the Inner Region of the 3C48 Host Galaxy
The well-known quasar 3C48 is the most powerful compact steep-spectrum
radio-loud QSO at low redshifts. It also has two unusual optical features
within the radius of the radio jet (~1"): (1) an anomalous, high-velocity
narrow-line component, having several times as much flux as does the
narrow-line component coinciding with the broad-line redshift; and (2) a bright
continuum peak (3C48A) ~1" northeast of the quasar. Both of these optical
features have been conjectured to be related to the radio jet. Here we explore
these suggestions. We have obtained Gemini North GMOS integral-field-unit (IFU)
spectroscopy of the central region around 3C48. We use the unique features of
the IFU data to remove unresolved emission at the position of the quasar. The
resolved emission at the wavelength of the high-velocity component is peaked
<~0.25" north of the quasar, at virtually the same position angle as the base
of the radio jet. These observations appear to confirm that this high-velocity
gas is connected with the radio jet. However, most of the emission comes from a
region where the jet is still well collimated, rather than from the regions
where the radio maps indicate strong interaction with an external medium. We
also present the results of HST STIS spectroscopy of 3C48A. We show that 3C48A
is dominated by stars with a luminosity-weighted age of ~1.4 X 10^8 years,
substantially older than any reasonable estimate for the age of the radio
source. Our IFU data indicate a similar age. Thus, 3C48A almost certainly
cannot be attributed to jet-induced star formation. The host galaxy of 3C48 is
clearly the result of a merger, and 3C48A seems much more likely to be the
distorted nucleus of the merging partner, in which star formation was induced
during the previous close passage.Comment: 10 pages, accepted by The Astrophysical Journa
The Host Galaxy and The Extended Emission-Line Region of The Radio Galaxy 3C 79
We present extensive ground-based spectroscopy and HST imaging of 3C79, an FR
II radio galaxy associated with a luminous extended emission-line region
(EELR). Surface brightness modeling of an emission-line-free HST R-band image
reveals that the host galaxy is a massive elliptical with a compact companion
0.8" away and 4 magnitudes fainter. The host galaxy spectrum is best described
by an intermediate-age (1.3 Gyr) stellar population (4% by mass), superimposed
on a 10 Gyr old population and a power law (\alpha_{\lambda} = -1.8); the
stellar populations are consistent with super-solar metallicities, with the
best fit given by the 2.5 Z_sun models. We derive a dynamical mass of 4E11
M_sun within the effective radius from the velocity dispersion. The EELR
spectra clearly indicate that the EELR is photoionized by the hidden central
engine. Photoionization modeling shows evidence that the gas metallicity in
both the EELR and the nuclear narrow-line region is mildly sub-solar (0.3 - 0.7
Z_sun) -- significantly lower than the super-solar metallicities deduced from
typical active galactic nuclei in the SDSS. The more luminous filaments in the
EELR exhibit a velocity field consistent with a common disk rotation. Fainter
clouds, however, show high approaching velocities that are uncoupled with this
apparent disk rotation. The striking similarities between this EELR and the
EELRs around steep-spectrum radio-loud quasars provide further evidence for the
orientation-dependent unification schemes. The metal-poor gas is almost
certainly not native to the massive host galaxy. We suggest that the close
companion galaxy could be the tidally stripped bulge of a late-type galaxy that
is merging with the host galaxy. The interstellar medium of such a galaxy is
probably the source for the low-metallicity gas in 3C79.Comment: Accepted for publication in ApJ. 13 pages, 12 figures, 3 tables.
Paper with figures at full resolution uploaded in this versio
3C 48: Stellar Populations and the Kinematics of Stars and Gas in the Host Galaxy
We present deep Keck LRIS spectroscopy of the host galaxy of 3C 48. Our
observations at various slit positions sample the different luminous components
near the quasar, including the apparent tidal tail to the NW and several strong
emission line regions.
By fitting Bruzual & Charlot (1996) population synthesis models to our
spectra, we obtain ages for the most recent major episodes of star formation in
various parts of the host galaxy covered by our slits. There is vigorous
current star formation in regions just NE and SE of the quasar and
post-starburst regions with ages up to ~10^8 years in other parts of the host
galaxy, but most of the NW tidal tail shows no sign of significant recent star
formation. We use these model fits, together with the kinematics of the stars
and gas, to outline a plausible evolutionary history for the host galaxy, its
recent starburst activity, the triggering of the quasar, and the interaction of
the radio jet with the ambient gas.
There is strong evidence that the 3C 48 host is an ongoing merger, and that
it is probably near the peak of its starburst activity. Nevertheless, the
quasar itself seems to suffer little extinction, perhaps because we are viewing
it along a particularly favorable line-of-sight.Comment: 27 pages plus 11 figures (7 postscript, 4 gif). Postscript version
including figures (1840 kb) available at
http://www.ifa.hawaii.edu/~canaguby/preprints.html . Accepted for publication
in Ap
Scattering of polarized laser light by an atomic gas in free space: a QSDE approach
We propose a model, based on a quantum stochastic differential equation
(QSDE), to describe the scattering of polarized laser light by an atomic gas.
The gauge terms in the QSDE account for the direct scattering of the laser
light into different field channels. Once the model has been set, we can
rigorously derive quantum filtering equations for balanced polarimetry and
homodyne detection experiments, study the statistics of output processes and
investigate a strong driving, weak coupling limit.Comment: 9 pages, 2 figure
The Extended Emission-Line Region of 4C 37.43
We have explored the nature of the extended emission-line region around the
z=0.37 quasar 4C 37.43, using extensive ground-based and HST imaging and
spectroscopy. The velocity field of the ionized gas shows gradual gradients
within components but large jumps between components, with no obvious global
organization. The HST [O III] image shows radial linear features on the east
side of the QSO that appear to mark the edges of an ionization cone.
Concentrating on the bright emission peaks ~4\arcsec$ east of the quasar, we
find through modeling that we require at least two density regimes contributing
significantly to the observed emission-line spectrum: one with a density of ~2
cm^-3, having essentially unity filling factor, and one with a density of ~500
cm^-3, having a very small (~10^-5) filling factor. Because the temperatures of
these two components are similar, they cannot be in pressure equilibrium, and
there is no obvious source of confinement for the dense regions. We estimate
that the dense regions will dissipate on timescales <~10^4 years and therefore
need to be continuously regenerated, most likely by shocks. Because we know
that some QSOs, at least, begin their lives in conjunction with merger-driven
massive starbursts in their host galaxies, an attractive interpretation is that
the extended emission region comprises gas that has been expelled as a result
of tidal forces during the merger and is now being shocked by the galactic
superwind from the starburst. This picture is supported by the observed
distribution of the ionized gas, the presence of velocities ranging up to ~700
km s^{-1}, and the existence of at least two QSOs having similarly luminous and
complex extended emission regions that are known to have ultra-luminous IR
galaxy hosts with current or recent starbursts.Comment: 22 pages, incl. 7 figures; to be published in The Astrophysical
Journal, 572 (June 20, 2002 issue
Tensor polarizability and dispersive quantum measurement of multilevel atoms
Optimally extracting information from measurements performed on a physical
system requires an accurate model of the measurement interaction. Continuously
probing the collective spin of an Alkali atom cloud via its interaction with an
off-resonant optical probe is an important example of such a measurement where
realistic modeling at the quantum level is possible using standard techniques
from atomic physics. Typically, however, tutorial descriptions of this
technique have neglected the multilevel structure of realistic atoms for the
sake of simplification. In this paper we account for the full multilevel
structure of Alkali atoms and derive the irreducible form of the polarizability
Hamiltonian describing a typical dispersive quantum measurement. For a specific
set of parameters, we then show that semiclassical predictions of the theory
are consistent with our experimental observations of polarization scattering by
a polarized cloud of laser-cooled Cesium atoms. We also derive the
signal-to-noise ratio under a single measurement trial and use this to predict
the rate of spin-squeezing with multilevel Alkali atoms for arbitrary detuning
of the probe beam.Comment: Significant corrections to theory and data. Full quality figures and
other information available from http://minty.caltech.edu/papers.ph
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