2,361 research outputs found
Decision making processes in people with symptoms of acute myocardial infarction: qualitative study
Objective To identify, the themes that influence decision making processes used by patients with symptoms of acute myocardial infarction. Design Qualitative study using semistructured interviews. Setting Two district hospitals in North Yorkshire. Participants 22 patients admitted to hospital with confirmed second, third, or fourth acute myocardial infarction. Main outcome measure Patients' perceptions of their experience between the onset of symptoms and the decision to seek medical help. Results Six main themes that influence the decision making process were identified: appraisal of In symptoms, perceived risk, previous experience, psychological and emotional factors, use of the NHS, and context of the event. Conclusions Knowledge of symptoms may not be enough to promote prompt action in the event of an acute myocardial infarction. Cognitive and emotional processes, individual beliefs and values, and the influence of the context of the event should also be considered in individual interventions designed to reduce delay in the event of symptoms of acute myocardial infarction
The Spitzer South Pole Telescope Deep Field Survey: Linking galaxies and halos at z=1.5
We present an analysis of the clustering of high-redshift galaxies in the
recently completed 94 deg Spitzer-SPT Deep Field survey. Applying flux and
color cuts to the mid-infrared photometry efficiently selects galaxies at
in the stellar mass range , making this
sample the largest used so far to study such a distant population. We measure
the angular correlation function in different flux-limited samples at scales
(corresponding to physical distances Mpc) and
thereby map the one- and two-halo contributions to the clustering. We fit halo
occupation distributions and determine how the central galaxy's stellar mass
and satellite occupation depend on the halo mass. We measure a prominent peak
in the stellar-to-halo mass ratio at a halo mass of , 4.5 times higher than the value. This supports
the idea of an evolving mass threshold above which star formation is quenched.
We estimate the large-scale bias in the range and the satellite
fraction to be , showing a clear evolution compared to
. We also find that, above a given stellar mass limit, the fraction of
galaxies that are in similar mass pairs is higher at than at . In
addition, we measure that this fraction mildly increases with the stellar mass
limit at , which is the opposite of the behavior seen at low-redshift.Comment: 32 pages, 22 figures. Published in MNRA
Age-specific incidence of A/H1N1 2009 influenza infection in England from sequential antibody prevalence data using likelihood-based estimation.
Estimating the age-specific incidence of an emerging pathogen is essential for understanding its severity and transmission dynamics. This paper describes a statistical method that uses likelihoods to estimate incidence from sequential serological data. The method requires information on seroconversion intervals and allows integration of information on the temporal distribution of cases from clinical surveillance. Among a family of candidate incidences, a likelihood function is derived by reconstructing the change in seroprevalence from seroconversion following infection and comparing it with the observed sequence of positivity among the samples. This method is applied to derive the cumulative and weekly incidence of A/H1N1 pandemic influenza in England during the second wave using sera taken between September 2009 and February 2010 in four age groups (1-4, 5-14, 15-24, 25-44 years). The highest cumulative incidence was in 5-14 year olds (59%, 95% credible interval (CI): 52%, 68%) followed by 1-4 year olds (49%, 95% CI: 38%, 61%), rates 20 and 40 times higher respectively than estimated from clinical surveillance. The method provides a more accurate and continuous measure of incidence than achieved by comparing prevalence in samples grouped by time period
Chandra and XMM-Newton Observations of RDCS1252.9-2927, A Massive Cluster at z=1.24
We present deep Chandra and XMM obervations of the galaxy cluster
RDCS1252.9-2927, which was selected from the ROSAT Deep Cluster Survey (RDCS)
and confirmed by extensive spectroscopy with the VLT at redshift z=1.237. With
the Chandra data, the X-ray emission from the intra-cluster medium is well
resolved and traced out to 500 kpc, thus allowing a measurement of the physical
properties of the gas with unprecedented accuracy at this redshift. We detect a
clear 6.7 keV Iron K line in the Chandra spectrum providing a redshift within
1% of the spectroscopic one. By augmenting our spectroscopic analysis with the
XMM data (MOS detectors only), we significantly narrow down the 1 sigma error
bar to 10% for the temperature and 30% for the metallicity, with best fit
values kT = 6.0(+0.7,-0.5) keV, Z = 0.36(+0.12,-0.10) Z_sun. In the likely
hypothesis of hydrostatic equilibrium, we measure a total mass of M_{500} =
(1.9+-0.3)10^14 h_70^{-1}M_sun within R_{Delta=500} = 536 kpc. Overall, these
observations imply that RDCS1252.9-2927 is the most X-ray luminous and likely
the most massive bona-fide cluster discovered to date at z>1. When combined
with current samples of distant clusters, these data lend further support to a
mild evolution of the cluster scaling relations, as well the metallicity of the
intra-cluster gas. Inspection of the cluster mass function in the current
cosmological concordance model (h,Omega_m,Omega_Lambda)=(0.7,0.3,0.7) and
sigma_8=0.7-0.8 shows that RDCS1252.9-2927 is an M* cluster at z=1.24, in
keeping with number density expectations in the RDCS survey volume.Comment: 9 pages, 1 color figure (fig6.jpg). The Astronomical Journal in press
(Jan 2004). Full resolution preprint available at
http://www.eso.org/~prosati/RDCS1252
The Galaxy Population of Cluster RXJ0848+4453 at z=1.27
We present a study of the galaxy population in the cluster RXJ0848+4453 at
z=1.27, using deep HST NICMOS and WFPC2 images. We morphologically classify all
galaxies to K_s=20.6 that are covered by the HST imaging, and determine
photometric redshifts using deep ground based BRIzJK_s photometry. Of 22 likely
cluster members with morphological classifications, eleven (50%) are classified
as early-type galaxies, nine (41%) as spiral galaxies, and two (9%) as
``merger/peculiar''. At HST resolution the second brightest cluster galaxy is
resolved into a spectacular merger between three red galaxies of similar
luminosity, separated from each other by ~6 kpc, with an integrated magnitude
K=17.6 (~3 L* at z=1.27). The two most luminous early-type galaxies also show
evidence for recent or ongoing interactions. Mergers and interactions between
galaxies are possible because RXJ0848+4453 is not yet relaxed. The fraction of
early-type galaxies in our sample is similar to that in clusters at 0.5<z<1,
and consistent with a gradual decrease of the number of early-type galaxies in
clusters from z=0 to z=1.3. We find evidence that the color-magnitude relation
of the early-type galaxies is less steep than in the nearby Coma cluster. This
may indicate that the brightest early-type galaxies have young stellar
populations at z=1.27, but is also consistent with predictions of single age
``monolithic'' models with a galactic wind. The scatter in the color-magnitude
relation is ~0.04 in rest frame U-V, similar to that in clusters at 0<z<1.
Taken together, these results show that luminous early-type galaxies exist in
clusters at z~1.3, but that their number density may be smaller than in the
local Universe. Additional observations are needed to determine whether the
brightest early-type galaxies harbor young stellar populations.Comment: Accepted for publication in The Astrophysical Journal Letter
Monte Carlo Comparisons to a Cryogenic Dark Matter Search Detector with low Transition-Edge-Sensor Transition Temperature
We present results on phonon quasidiffusion and Transition Edge Sensor (TES)
studies in a large, 3 inch diameter, 1 inch thick [100] high purity germanium
crystal, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed
with 59.5 keV gamma-rays from an Am-241 calibration source. We compare
calibration data with results from a Monte Carlo which includes phonon
quasidiffusion and the generation of phonons created by charge carriers as they
are drifted across the detector by ionization readout channels. The phonon
energy is then parsed into TES based phonon readout channels and input into a
TES simulator
Clustering of red galaxies around the z=1.53 quasar 3C270.1
In the paradigm of hierarchical galaxy formation, luminous radio galaxies
mark mass assembly peaks that should contain clusters of galaxies. Observations
of the z=1.53 quasar 3C270.1 with the Spitzer Space Telescope at 3.6-24 micron
and with the 6.5-m MMT in the z'- and Y-bands allow detection of potential
cluster members via photometric redshifts. Compared with nearby control fields,
there is an excess of 11 extremely red objects (EROs) at 1.33 < z_phot < 1.73,
consistent with a proto-cluster around the quasar. The spectral energy
distributions (SEDs) of 3/4 of the EROs are better fitted with passive
elliptical galaxies than withdust-reddened starbursts, and of four sources
well-detected on an archival HST snapshot image, all have undisturbed
morphologies. However, one ERO, not covered by the HST image, is a double
source with 0.8" separation on the z' image and a marginal (2sigma) 24 micron
detection indicating a dust-enshrouded starburst. The EROs are more luminous
than L* (H = -23.6 AB mag at z=1.5).Comment: 12 pages, 7 figures, accepted by Ap
Leprosy Associated with Atypical Cutaneous Leishmaniasis in Nicaragua and Honduras
In Central America, few cases of leprosy have been reported, but the disease may be unrecognized. Diagnosis is based on clinical criteria and histology. Preliminary field work in Nicaragua and Honduras found patients, including many children, with skin lesions clinically suggestive of atypical cutaneous leishmaniasis or indeterminate leprosy. Histology could not distinguish these diseases although acid-fast organisms were visible in a few biopsies. Lesions healed after standard antimicrobial therapy for leprosy. In the present study, patients, family members, and other community members were skin-tested and provided nasal swabs and blood samples. Biopsies were taken from a subgroup of patients with clinical signs of infection. Two laboratories analyzed samples, using local in-house techniques. Mycobacterium leprae, Leishmania spp. and Leishmania infantum were detected using polymerase chain reactions. Mycobacterium leprae DNA was detected in blood samples and nasal swabs, including some cases where leprosy was not clinically suspected. Leishmania spp. were also detected in blood and nasal swabs. Most biopsies contained Leishmania DNA and coinfection of Leishmania spp. with M. leprae occurred in 33% of cases. Mycobacterium leprae DNA was also detected and sequenced from Nicaraguan and Honduran environmental samples. In conclusion, leprosy and leishmaniasis are present in both regions, and leprosy appears to be widespread. The nature of any relationship between these two pathogens and the epidemiology of these infections need to be elucidated
A VLT spectroscopic survey of RX J0152.7-1357, a forming cluster of galaxies at z=0.837
We present the results of an extensive spectroscopic survey of RX
J0152.7-1357, one of the most massive distant clusters of galaxies known.
Multi-object spectroscopy, carried out with FORS1 and FORS2 on the ESO Very
Large Telescope (VLT), has allowed us to measure more than 200 redshifts in the
cluster field and to confirm 102 galaxies as cluster members. The mean redshift
of the cluster is and we estimate the velocity dispersion
of the overall cluster galaxy distribution to be $\sim 1600 \mathrm{km \
s^{-1}}\sim919\sim737 \mathrm{km s^{-1}}\lambda$3727) emission lines is
observed in the outskirts of the cluster. Two AGNs, which were previously
confused with the diffuse X-ray emission from the intracluster medium in ROSAT
and BeppoSAX observations, are found to be cluster members.Comment: 16 pages. 13 figures. Accepted for publication in Astronomy &
Astrophysics. Tables 4 and 5 available in printed version. Corrected typos
and missing reference
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