160 research outputs found
Increasing the knowledge, identification and treatment of osteoporosis through education and shared decision-making with residents living in a retirement village community
Objective: This pilot study explored whether individual goal setting in a retirement village setting could improve strategies to strengthen bones in an ageing population and help prevent osteoporosis.
Methods: A two-phased osteoporosis prevention program was developed, piloted and evaluated involving a group education session followed by the development of individualised Bone Plans based upon personal understanding of individual fracture risk and lifestyle factors.
Results: A significant improvement in knowledge and understanding of factors to prevent and manage osteoporosis was achieved, and changes in lifestyle behaviours were sustained at six months.
Conclusion: Success was due to education by specialist medical and health personnel, flexibility of goal setting, use of group sessions and location of the program within the retirement community setting. The ‘Mind Your Bones’ program is a feasible and acceptable way to translate preventative bone health messages to a large number of people via the retirement village network
Weighing the Giants - I. Weak-lensing masses for 51 massive galaxy clusters: project overview, data analysis methods and cluster images
This is the first in a series of papers in which we measure accurate
weak-lensing masses for 51 of the most X-ray luminous galaxy clusters known at
redshifts 0.15<z<0.7, in order to calibrate X-ray and other mass proxies for
cosmological cluster experiments. The primary aim is to improve the absolute
mass calibration of cluster observables, currently the dominant systematic
uncertainty for cluster count experiments. Key elements of this work are the
rigorous quantification of systematic uncertainties, high-quality data
reduction and photometric calibration, and the "blind" nature of the analysis
to avoid confirmation bias. Our target clusters are drawn from RASS X-ray
catalogs, and provide a versatile calibration sample for many aspects of
cluster cosmology. We have acquired wide-field, high-quality imaging using the
Subaru and CFHT telescopes for all 51 clusters, in at least three bands per
cluster. For a subset of 27 clusters, we have data in at least five bands,
allowing accurate photo-z estimates of lensed galaxies. In this paper, we
describe the cluster sample and observations, and detail the processing of the
SuprimeCam data to yield high-quality images suitable for robust weak-lensing
shape measurements and precision photometry. For each cluster, we present
wide-field color optical images and maps of the weak-lensing mass distribution,
the optical light distribution, and the X-ray emission, providing insights into
the large-scale structure in which the clusters are embedded. We measure the
offsets between X-ray centroids and Brightest Cluster Galaxies in the clusters,
finding these to be small in general, with a median of 20kpc. For offsets
<100kpc, weak-lensing mass measurements centered on the BCGs agree well with
values determined relative to the X-ray centroids; miscentering is therefore
not a significant source of systematic uncertainty for our mass measurements.
[abridged]Comment: 26 pages, 19 figures (Appendix C not included). Accepted after minor
revisio
RASS-SDSS Galaxy Cluster Survey. V. The X-ray-Underluminous Abell Clusters
In this paper we consider a large sample of optically selected clusters, in
order to elucidate the physical reasons for the existence of X-ray
underluminous clusters. For this purpose we analyze the correlations of the
X-ray and optical properties of a sample of 137 spectroscopically confirmed
Abell clusters in the SDSS database. We search for the X-ray counterpart of
each cluster in the ROSAT All Sky Survey. We find that 40% of our clusters have
a marginal X-ray detection or remain undetected in X-rays. These clusters
appear too X-ray faint on average for their velocity dispersion determined
mass, i.e. they do not follow the scaling relation between X-ray luminosity and
virial mass traced by the other clusters. On the other hand, they do follow the
general scaling relation between optical luminosity and virial mass. We refer
to these clusters as the X-ray-Underluminous Abell clusters (AXU clusters, for
short) and designate as 'normal' the X-ray detected Abell systems. We examine
the distributions and properties of the galaxy populations of the normal and
the AXU clusters, separately. The AXU clusters are characterized by leptokurtic
(more centrally concentrated than a Gaussian) velocity distribution of their
member galaxies in the outskirts (), as expected for
the systems in accretion. In addition, the AXU clusters have a higher fraction
of blue galaxies in the external region and show a marginally significant
paucity of galaxies at the center. Our results seem to support the
interpretation that the AXU clusters are systems in formation undergoing a
phase of mass accretion. Their low X-ray luminosity should be due to the still
accreting Intracluster gas or to an ongoing merging process.Comment: 19 pages, 11 figures, A&A in pres
Cluster Abell 520: a perspective based on member galaxies. A cluster forming at the crossing of three filaments?
The connection of cluster mergers with the presence of extended, diffuse
radio sources in galaxy clusters is still debated. An interesting case is the
rich, merging cluster Abell 520, containing a radio halo. A recent
gravitational analysis has shown in this cluster the presence of a massive dark
core suggested to be a possible problem for the current cold dark matter
paradigm.
We aim to obtain new insights into the internal dynamics of Abell 520
analyzing velocities and positions of member galaxies.
Our analysis is based on redshift data for 293 galaxies in the cluster field
obtained combining new redshift data for 86 galaxies acquired at the TNG with
data obtained by CNOC team and other few data from the literature. We also use
new photometric data obtained at the INT telescope. We combine galaxy
velocities and positions to select 167 cluster members around z~0.201. We
analyze the cluster structure using the weighted gap analysis, the KMM method,
the Dressler-Shectman statistics and the analysis of the velocity dispersion
profiles. We compare our results with those from X-ray, radio and gravitational
lensing analyses.
We find that Abell 520 is definitely a very complex system. Our results
suggest that we are looking at a cluster forming at the crossing of three
filaments of the large scale structure. In particular, we detect a filament
aligned with the LOS and projected onto the center of the forming cluster. It
might explain the apparent massive dark core shown by gravitational lensing
analysis.Comment: 18 pages, 16 figures, 4 tables. Accepted for publication on A&
Internal dynamics of the radio-halo cluster A2744
We present a detailed dynamical analysis of the rich galaxy cluster A2744,
containing a powerful diffuse radio halo.Our analysis is based on redshift data
for 102 galaxies, part of them recovered from unexplored spectra in the ESO
archive. We combine galaxy velocity and position information to select the
cluster members and determine global dynamical properties of the cluster. We
use a variety of statistical tests to detect possible substructures. We find
that A2744 appears as a well isolated peak in the redshift space at =0.306,
which includes 85 galaxies recognized as cluster members. We compute the
line-of-sight (LOS) velocity dispersion of galaxies (~1750 km/sec), which is
significantly larger than what is expected in the case of a relaxed cluster
with an observed X-ray temperature of 8 keV. We find evidence that this cluster
is far from dynamical equilibrium, as shown by the non-Gaussian nature of the
velocity distribution, the presence of a velocity gradient and a significant
substructure. In particular, our results suggest a merging scenario of two
clumps with a mass ratio of 3:1 and a LOS impact velocity (rest frame) of ~3000
km/sec, likely observed just after the core passage. The merging is occuring
roughly in the NS direction with the axis close to the LOS. This scenario
agrees with that proposed on the basis of recent Chandra results in its general
lines, although suggesting a somewhat more advanced merging phase.Comment: 14 pages. Paper in press on Astronomy & Astrophysic
Sensitivity and Insensitivity of Galaxy Cluster Surveys to New Physics
We study the implications and limitations of galaxy cluster surveys for
constraining models of particle physics and gravity beyond the Standard Model.
Flux limited cluster counts probe the history of large scale structure
formation in the universe, and as such provide useful constraints on
cosmological parameters. As a result of uncertainties in some aspects of
cluster dynamics, cluster surveys are currently more useful for analyzing
physics that would affect the formation of structure than physics that would
modify the appearance of clusters. As an example we consider the Lambda-CDM
cosmology and dimming mechanisms, such as photon-axion mixing.Comment: 24 pages, 8 eps figures. References added, discussion of scatter in
relations between cluster observables lengthene
Global Properties of the Rich Cluster ABCG 209 at z~0.2. Spectroscopic and Photometric Catalogue
This paper is aimed at giving an overview of the global properties of the
rich cluster of galaxies ABCG 209. This is achieved by complementing the
already available data with new medium resolution spectroscopy and NIR
photometry which allow us to i) analyse in detail the cluster dynamics,
distinguishing among galaxies belonging to different substructures and deriving
their individual velocity distributions, using a total sample of 148 galaxies
in the cluster region, of which 134 belonging to the cluster; ii) derive the
cluster NIR luminosity function; iii) study the Kormendy relation and the
photometric plane of cluster early-type galaxies (ETGs). Finally we provide an
extensive photometric (optical and NIR) and spectroscopic dataset for such a
complex system to be used in further analyses investigating the nature,
formation and evolution of rich clusters of galaxies. The observational
scenario confirms that ABCG 209 is presently undergoing strong dynamical
evolution with the merging of two or more subclumps. This interpretation is
also supported by the detection of a radio halo (Giovannini et al. 2006)
suggesting that there is a recent or ongoing merging. Cluster ETGs follow a
Kormendy relation whose slope is consistent with previous studies both at
optical and NIR wavelengths. We investigate the origin of the intrinsic scatter
of the photometric plane due to trends of stellar populations, using line
indices as indicators of age, metallicity and alpha/Fe enhancement. We find
that the chemical evolution of galaxies could be responsible for the intrinsic
dispersion of the Photometric Plane.Comment: 39 pages, 17 figures, MNRAS in pres
Internal dynamics of the z sim 0.8 cluster RX J0152.7-1357
We present the results from the dynamical analysis of the cluster of galaxies
RX J0152-1357, which shows a complex structure in its X-ray emission, with two
major clumps in the central region, and a third clump in the Eastern region.
Our analysis is based on redshift data for 187 galaxies. We compute the
line-of-sight velocity dispersion of galaxies, sigma_V=1322^+74_-68 kms^-1,
which is significantly larger than what is expected in the case of a relaxed
cluster with an observed X-ray temperature of 5-6 keV. We find evidence that
this cluster is far from dynamical equilibrium, as shown by the non Gaussianity
of the velocity distribution, the presence of a velocity gradient and
significant substructure. Our analysis shows that the high value of sigma_V is
due to the complex structure of RX J0152-1357, i.e. to the presence of three
galaxy clumps of different mean velocity. Using optical data we detect a
low-velocity clump (with sigma_V=300-500 kms^-1) in the central SW region and a
high--velocity clump (with sigma_V sim 700 kms^-1) in the E region, well
corresponding to the SW and E peaks detected in the X-ray emission. The central
NE X-ray peak is associated to the main galaxy structure with a velocity which
is intermediate between those of the other two clumps and sigma_V sim 900
kms^-1. The mass of the whole system within 2 Mpc is estimated to lie in the
range (1.2-2.2)X10^{15} M_sun. Analytic calculations based on the two-body
model indicate that the system is most likely bound, currently undergoing
merging. In particular, we suggest that the SW clump is not a small group, but
rather the dense cluster-core of a massive cluster.Comment: 14 pages, 15 eps figures, A&A accepte
Tumor markers in breast cancer - European Group on Tumor Markers recommendations
Recommendations are presented for the routine clinical use of serum and tissue-based markers in the diagnosis and management of patients with breast cancer. Their low sensitivity and specificity preclude the use of serum markers such as the MUC-1 mucin glycoproteins ( CA 15.3, BR 27.29) and carcinoembryonic antigen in the diagnosis of early breast cancer. However, serial measurement of these markers can result in the early detection of recurrent disease as well as indicate the efficacy of therapy. Of the tissue-based markers, measurement of estrogen and progesterone receptors is mandatory in the selection of patients for treatment with hormone therapy, while HER-2 is essential in selecting patients with advanced breast cancer for treatment with Herceptin ( trastuzumab). Urokinase plasminogen activator and plasminogen activator inhibitor 1 are recently validated prognostic markers for lymph node-negative breast cancer patients and thus may be of value in selecting node-negative patients that do not require adjuvant chemotherapy. Copyright (C) 2005 S. Karger AG, Basel
An X-ray Census of Young Stars in the Massive Southern Star-Forming Complex NGC 6357
We present the first high spatial resolution X-ray study of the massive star
forming region NGC 6357, obtained in a 38 ks Chandra/ACIS observation. Inside
the brightest constituent of this large HII region complex is the massive open
cluster Pismis 24. It contains two of the brightest and bluest stars known, yet
remains poorly studied; only a handful of optically bright stellar members have
been identified. We investigate the cluster extent and Initial Mass Function
and detect ~800 X-ray sources with a limiting sensitivity of 10^{30} ergs
s^{-1}; this provides the first reliable probe of the rich intermediate-mass
and low-mass population of this massive cluster, increasing the number of known
members from optical study by a factor of ~50. The high luminosity end (log
L_h[2-8 keV]\ge 30.3 ergs s^{-1}) of the observed X-ray luminosity function in
NGC 6357 is clearly consistent with a power law relation as seen in the Orion
Nebula Cluster and Cepheus B, yielding the first estimate of NGC 6357's total
cluster population, a few times the known Orion population. We investigate the
structure of the cluster, finding small-scale substructures superposed on a
spherical cluster with 6 pc extent, and discuss its relationship to the nebular
morphology. The long-standing Lx - 10^{-7}L_{bol} correlation for O stars is
confirmed. Twenty-four candidate O stars and one possible new obscured massive
YSO or Wolf-Rayet star are presented. Many cluster members are estimated to be
intermediate-mass stars from available infrared photometry (assuming an age of
1 Myr), but only a few exhibit K-band excess. We report the first detection of
X-ray emission from an Evaporating Gaseous Globule at the tip of a molecular
pillar; this source is likely a B0-B2 protostar.Comment: 64 pages (double columns), 9 table, 17 figures (reduced resolution),
ApJ accepted. Please contact J. Wang for full table
- …