4,052 research outputs found
Developing a questionnaire to assess community severance, walkability, and wellbeing: results from the Street Mobility Project in London
This working paper describes the development of the survey questionnaire component of the toolkit designed to measure community severance, and assess its potential associations with transport and health. We discuss the cognitive testing and piloting of the questionnaire in two contrasting case study areas in inner London, and present results from the survey data
Oxygen Gas Abundances at 0.4<z<1.5: Implications for the Chemical Evolution History of Galaxies
We report VLT-ISAAC and Keck-NIRSPEC near-infrared spectroscopy for a sample
of 30 0.47<z<0.92 CFRS galaxies and five [OII]-selected, M_B,AB<-21.5, z~1.4
galaxies. We have measured Halpha and [NII] line fluxes for the CFRS galaxies
which have [OII], Hbeta and [OIII] line fluxes available from optical
spectroscopy. For the z~1.4 objects we measured Hbeta and [OIII] emission line
fluxes from J-band spectra, and Halpha line fluxes plus upper limits for [NII]
fluxes from H-band spectra. We derive the extinction and oxygen abundances for
the sample using a method based on a set of ionisation parameter and oxygen
abundance diagnostics, simultaneously fitting the [OII], Hbeta, [OIII], Halpha
and [NII] line fluxes. Our most salient conclusions are: a) the source of gas
ionisation in the 30 CFRS and in all z~1.4 galaxies is not due to AGN activity;
b) about one third of the 0.47<z<0.92 CFRS galaxies in our sample have
substantially lower metallicities than local galaxies with similar luminosities
and star formation rates; c) comparison with a chemical evolution model
indicates that these low metallicity galaxies are unlikely to be the
progenitors of metal-poor dwarf galaxies at z~0, but more likely the
progenitors of massive spirals; d) the z~1.4 galaxies are characterized by the
high [OIII]/[OII] line ratios, low extinction and low metallicity that are
typical of lower luminosity CADIS galaxies at 0.4<z<0.7, and of more luminous
Lyman Break Galaxies at z~3.1, but not seen in CFRS galaxies at 0.4<z<1.0; e)
the properties of the z~1.4 galaxies suggest that the period of rapid chemical
evolution takes place progressively in lower mass systems as the universe ages,
and thus provides further support for a downsizing picture of galaxy formation,
at least from z~1.4 to today.Comment: Proceedings contribution for "The Fabulous Destiny of Galaxies;
Bridging Past and Present", Marseille, 200
High-Resolution K' Imaging of the z = 1.786 Radio Galaxy 3C 294
We have obtained imaging in the K' band (~I-band rest frame) of the z=1.786
radio galaxy 3C 294 with the 36-element curvature-sensing adaptive optics
system Hokupa`a and the Canada-France-Hawaii Telescope. At a resolution of <
\~0."15, the galaxy is seen as a group of small but resolved knots distributed
over a roughly triangular region ~1."4 across. The interpretation of the
structure depends on the location of the nucleus, as indicated by the compact
radio core. Its position is uncertain by > ~0."5 (2-sigma) because of
uncertainties in the optical astrometry, but our best estimate places it at or
near the southern apex of the distribution. If this location is correct, the
most likely interpretation is that of a hidden quasar nucleus illuminating
dusty infalling dwarf-galaxy-like clumps having characteristic sizes of ~1.5
kpc.Comment: 8 pages. One figure in gif format. Postscript version including fig.
(240 kb) available at http://www.ifa.hawaii.edu/~canaguby/preprints.html To
appear in ApJ. Letter
Medical planning for military operations other then [i.e. than] war: Is a paradigm shift required?
Military operations other than war are increasing in frequency and, as one might surmise present unique challenges to the operational commander and the medical planner. Over time and by necessity the U.S. military has developed a logistical support system with unprecedented capability. This logistical system includes a medical system that is increasingly called upon to provide care to people outside the normal scope. Increased participation means Navy assets will be tasked to provide care to U.S. troops, U.N. troops, multinational troops, NGO personnel, and the civilians that precipitated the need for intervention in the first place. The current planning paradigm is rightfully focused on combat support. This thesis will investigate the necessity of breaking away from that paradigm when planning MOOTW.http://archive.org/details/medicalplanningf109459791Lieutenant, United States NavyApproved for public release; distribution is unlimited
A Companion Galaxy to the Post-Starburst Quasar UN J1025-0040
UN J1025-0040 is a quasar at z = 0.6344 that shows an extremely bright post
starburst population of age ~ 400 Myr (Brotherton et al. 1999). Images of UN
J1025-0040 show a nearly stellar object 4.2 arcseconds SSW of the quasar. We
present imaging and spectroscopy that confirm that this object is a companion
galaxy at redshift z = 0.6341. We estimate an age of ~ 800 Myr for the dominant
stellar population in the companion. The companion appears to be interacting
with the quasar host galaxy, and this interaction may have triggered both the
starburst and the quasar activity in UN J1025-0040.Comment: 8 pages plus 4 figures (2 postscript, 2 jpg). Postscript version
available at http://www.ifa.hawaii.edu/~canaguby/preprints.html To appear in
the January 2000 issue of A
Near-Infrared Spectroscopy of 0.4<z<1.0 CFRS Galaxies: Oxygen Abundances, SFRs and Dust
Using new J-band VLT-ISAAC and Keck-NIRSPEC spectroscopy, we have measured
Halpha and [NII] line fluxes for 0.47<z<0.92 CFRS galaxies which have [OII],
Hbeta and [OIII]a line fluxes available from optical spectroscopy, to
investigate how the properties of the star forming gas in galaxies evolve with
redshift. We derive the extinction and oxygen abundances for the sample using a
method based on a set of ionisation parameter and oxygen abundance diagnostics,
simultaneously fitting the [OII], Hbeta,[OIII], Halpha, and [NII] line fluxes.
The individual reddening measurements allow us to accurately correct the
Halpha-based star formation rate (SFR) estimates for extinction. Our most
salient conclusions are: a) in all 30 CFRS galaxies the source of gas
ionisation is not due to AGN activity; b) we find a range of 0<AV<3, suggesting
that it is important to determine the extinction for every single galaxy in
order to reliably measure SFRs and oxygen abundances in high redshift galaxies;
c) high values of [NII]/Halpha >0.1 for most (but not all) of the CFRS galaxies
indicate that they lie on the high-metallicity branch of the R23 calibration;
d) about one third of the 0.47<z<0.92 CFRS galaxies in our sample have lower
metallicities than local galaxies with similar luminosities and star formation
rates; e) comparison with a chemical evolution model indicates that these low
metallicity galaxies are unlikely to be the progenitors of metal-poor dwarf
galaxies at z~0.Comment: Accepted for publication in the Astrophysical Journa
Community severance and health: measuring community severance and examining its impact on the health of adults in Great Britain
BACKGROUND
Aspects of community severance (the separation of people from goods, services, and each other by busy roads or other transport infrastructure) have been linked to poor health and wellbeing, but few studies have examined this relationship. We created a novel index for community severance and estimated its association with the self-rated health of adults in Great Britain.
METHODS
Data were collected from a nationally representative online panel survey of 4,111 participants, February-July 2016. To construct an index, polychoric factor analysis (suitable for ordinal variables), was conducted on four survey items related to the perceived impact of roads on ability to walk locally. Community severance index (CSI) scores were negatively skewed, so were categorised into four groups (lowest 40%, second, third, highest). We examined the association of community severance with
self-rated health (âgoodâ (very good/good) vs. âpoorâ (fair/bad/very bad)) using logistic regression, adjusting for potential confounders (age, income, employment status).
MAIN RESULTS
Polychoric factor analysis confirmed that it was appropriate to combine the four survey items into a single index (Cronbachâs Alpha=0.86; Keiser-Meyer-Olkin measure of sampling adequacy= 0.76, factor loadings >0.74). After controlling for confounding factors, being in the highest CSI group was associated with higher odds of reporting poor self-rated health (Odds Ratio: 1.79, 95% Confidence Interval: 1.48-2.17) compared with the lowest CSI group. There was a dose-response gradient, with those in the second and third highest CSI groups having increased odds of reporting poor
self-rated health, though of lower magnitude ((1.21, 1.01-1.45) and (1.41, 1.16-1.71) respectively).
CONCLUSIONS
We found an inverse association between CSI and self-rated health. This suggests that to improve health, local governments and road authorities should take steps to reduce community severance through traffic reduction and calming, pedestrian prioritisation, and the installation of well-designed crossing points
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
A Kiloparsec-Scale Binary Active Galactic Nucleus Confirmed by the Expanded Very Large Array
We report the confirmation of a kpc-scale binary active galactic nucleus
(AGN) with high-resolution radio images from the Expanded Very Large Array
(EVLA). SDSS J150243.1+111557 is a double-peaked [O III] AGN at z = 0.39
selected from the Sloan Digital Sky Survey. Our previous near-infrared adaptive
optics imaging reveals two nuclei separated by 1.4" (7.4 kpc), and our optical
integral-field spectroscopy suggests that they are a type-1--type-2 AGN pair.
However, these data alone cannot rule out the single AGN scenario where the
narrow emission-line region associated with the secondary is photoionized by
the broad-line AGN in the primary. Our new EVLA images at 1.4, 5.0, and 8.5 GHz
show two steep-spectrum compact radio sources spatially coincident with the
optical nuclei. The radio power of the type-2 AGN is an order-of-magnitude in
excess of star-forming galaxies with similar extinction-corrected [O II] 3727
luminosities, indicating that the radio emission is powered by accretion.
Therefore, SDSS J150243.1+111557 is one of the few confirmed kpc-scale binary
AGN systems. Spectral-energy-distribution modeling shows that SDSS
J150243.1+111557 is a merger of two ~10^{11} M_sun galaxies. With both black
hole masses around 10^8 Msun, the AGNs are accreting at ~10 times below the
Eddington limit.Comment: ApJL accepted. 6 pages, 3 figures, 1 tabl
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