15 research outputs found
The Resolved Outer Population of NGC6822 with WFPC2
We present F336W (U), F439W (B), F555W (V), and F675W (R) Wide Field
Planetary Camera 2 (WFPC2) photometry of two outer regions of the Local Group
dwarf irregular galaxy NGC6822. The NE region is ~13 arcmin from the galaxy
centre, while the W region lies 10 arcmin out, and within the wispy low surface
brightness outer regions of the galaxy. The fields are not crowded and contain
few NGC 6822 stars. We discuss errors and uncertainties and find that the W
region contains a main sequence that extends to stars of about 2 solar masses,
with an age of about 200 Myr. The NE region has no main sequence or stars
younger than 1 Gyr, but does contain some luminous red stars that are not
matched in the W field. These stars are not clumped in the field. The results
suggest that the W region may be a trace of a tidal event that triggered the
current star-formation in this isolated galaxy.Comment: 12 pages including 2 tables, plus 4 figures (#1 omitted) To appear in
PAS
Heavy and Complex X-ray Absorption Towards the Nucleus of Markarian 6
We have used the ASCA satellite to make the first X-ray spectra of Markarian
6, a bright Seyfert 1.5 galaxy with complex and variable permitted lines, an
ionization cone, and remarkable radio structures. Our 0.6--9.5 keV spectra
penetrate to the black hole core of this Seyfert and reveal heavy and complex
intrinsic X-ray absorption. Both total covering and single partial covering
models fail to acceptably fit the observed absorption, and double partial
covering or partial covering plus warm absorption appears to be required. The
double partial covering model provides the best statistical fit to the data,
and we measure large column densities of ~ (3-20) * 10^{22} cm^{-2}
irrespective of the particular spectral model under consideration. These X-ray
columns are over an order of magnitude larger than expected based on
observations at longer wavelengths. Our data suggest that most of the X-ray
absorption occurs either in gas that has a relatively small amount of dust or
in gas that is located within the Broad Line Region. The X-ray absorber may
well be the putative `atmosphere' above the torus that collimates the
ionization cone. We also detect an apparently broad 6.4 keV iron K-alpha line,
and we present optical spectra demonstrating that the optical emission lines
were in a representative state during our ASCA observation.Comment: 30 pages, 7 figures, Astrophysical Journal. Paper is also available
at: http://www.astro.psu.edu/users/johnf/Text/research.htm
Young and Intermediate-age Distance Indicators
Distance measurements beyond geometrical and semi-geometrical methods, rely
mainly on standard candles. As the name suggests, these objects have known
luminosities by virtue of their intrinsic proprieties and play a major role in
our understanding of modern cosmology. The main caveats associated with
standard candles are their absolute calibration, contamination of the sample
from other sources and systematic uncertainties. The absolute calibration
mainly depends on their chemical composition and age. To understand the impact
of these effects on the distance scale, it is essential to develop methods
based on different sample of standard candles. Here we review the fundamental
properties of young and intermediate-age distance indicators such as Cepheids,
Mira variables and Red Clump stars and the recent developments in their
application as distance indicators.Comment: Review article, 63 pages (28 figures), Accepted for publication in
Space Science Reviews (Chapter 3 of a special collection resulting from the
May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space
Age
Is there an association between hospital accreditation and patient satisfaction with hospital care? A survey of 37 000 patients treated by 73 hospitals
Objective: In many countries hospitals are undergoing accreditation as mandatory or voluntary measures. It is believed that accreditation positively influence quality of care and patient satisfaction. This survey aims at assessing the relationship between patient satisfaction and accreditation status.
Design: Between January and May 2007, 4 weeks after their discharge, 78 508 patients from 328 departments in 73 hospitals received a validated questionnaire. Data from 36 777 patients (response rate 55%) were available for analyses.
Main: Outcome Measures Recommendation rate was used as primary endpoint, which was available from 35 945 patients. To address the clustering of patients within hospitals, we applied univariate and multivariable generalized estimating equations. As covariates we used âgenderâ and âageâ at the patient level and the ânumber of bedsâ and âhospital teaching statusâ at the hospital level.
Results: Overall and not addressing the clustering, 66.3% of all the patients recommend their hospital to others. This recommendation, however, was not related to the accreditation status in the univariate analyses (odds ratio (OR) for accreditation (âyesâ) and recommendation (âyesâ) 0.99, 95% confidence interval (CI) 0.85â1.16, P= 0.92). This result was similar in the multivariable regression model adjusted for clustering (OR = 0.98, 95% CI 0.84â1.13, P= 0.74).
Conclusions: Our results support the notion that accreditation is not linked to measurable better quality of care as perceived by the patient. Hospital accreditation may represent a step towards total quality management, but may not be a key factor to quality of care measured by the patient's willingness to recommend.C. Sack, A. Scherag, P. LĂŒtkes, W. GĂŒnther, K.-H. Jöckel and G. Holtman
Rare data on a rocky shore fish reproductive biology: sex ratio, length of first maturation and spawning period of Abudefduf saxatilis (Linnaeus, 1758) with notes on Stegastes variabilis spawning period (Perciformes: Pomacentridae) in SĂŁo Paulo, Brazil
This study presents data on the reproduction of Abudefduf saxatilis, a rocky shore inhabitant at the northern coast of SĂŁo Paulo State. A total of 73 individuals were collected using hooks and baits. They were measured, weighed and dissected, sex and maturation stage were analysed, first macroscopically, then part of the material was taken for microscopical confirmation. Visual censuses were also done for underwater observation of egg's presence. Results showed equivalence of males and females in the population, first maturation occurring between 101 and 115mm of total length, spawning period occurs from November to February for Abudefduf saxatilis and October to January for Stegastes variabilis. Reproductive period for A. saxatilis was positively related to air temperature and thermic amplitude, but the environmental clue most likely to influence this rhythm is photoperiod. Transects with visual census of males guarding eggs were also a reliable tool for finding reproductive period in these demersal, egg-guarder species.<br>Esse estudo apresenta dados sobre a reprodução de Abudefduf saxatilis, uma espĂ©cie habitante de costĂ”es rochosos no litoral norte do estado de SĂŁo Paulo. Os peixes foram coletados com anzol e isca num total de 73 indivĂduos, foram medidos, pesados, dissecados, seu sexo e maturidade gonadal foram analisados, primeiro macroscopicamente, depois parte desse material foi levado para confirmação microscĂłpica. Censos visuais tambĂ©m foram feitos para observar a presença de ovos. Os resultados apontam para uma equivalĂȘncia entre o nĂșmero de machos e fĂȘmeas na população, a primeira maturação ocorre entre 101 e 115 mm de comprimento total, a desova ocorre entre os meses de novembro a fevereiro em Abudefduf saxatilis e outubro a janeiro em Stegastes variabilis. O perĂodo reprodutivo de A. saxatilis estĂĄ positivamente relacionado Ă temperatura do ar e amplitude tĂ©rmica, mas o indicador ambiental mais provĂĄvel de influenciar o ritmo reprodutivo Ă© o fotoperĂodo. Os censos visuais feitos com a transecção mostraram-se uma ferramenta confiĂĄvel para encontrar o perĂodo de desova nessas espĂ©cies demersais que guardam seus ovos
Correlated multiwavelength emission from the X-ray-bright Seyfert galaxy III Zw 2
âThe definitive version is available at www.blackwell-synergy.com '. Copyright Blackwell Publishing. DOI: 10.1046/j.1365-8711.2002.05603.x [Full text of this article is not available in the UHRA]Peer reviewe