HI Detection in two Dwarf S0 Galaxies in Nearby Groups: ESO384-016 and NGC 59

An \hi survey of 10 dE/dS0 galaxies in the nearby Sculptor and Centaurus A groups was made using the Australia Telescope Compact Array (ATCA). The observed galaxies have accurate distances derived by Jerjen et al (1998; 2000b) using the surface brightness fluctuation technique. Their absolute magnitudes are in the range $-9.5 > M_B > -15.3$. Only two of the ten galaxies were detected at our detection limit ($\sim 1.0 \times 10^6$ \msol for the Centaurus group and $\sim 5.3 \times 10^5$ \msol for the Sculptor group), the two dS0 galaxies ESO384-016 in the Centaurus A Group and NGC 59 in the Sculptor Group, with \hi masses of $6.0 \pm 0.5 \times 10^6$ \msol and $1.4 \pm 0.1 \times 10^7$ \msol respectively. Those two detections were confirmed using the Green Bank Telescope. These small \hi reservoirs could fuel future generations of low level star formation and could explain the bluer colors seen at the center of the detected galaxies. Similarly to what is seen with the Virgo dEs, the two objects with \hi appear to be on the outskirt of the groups.Comment: 25 pages (11 figures), accepted by A

The Recent Star Formation History of NGC 5102

We present Hubble Space Telescope photometry of young stars in NGC 5102, a nearby gas-rich post-starburst S0 galaxy with a bright young stellar nucleus. We use the IAC-pop/MinnIAC algorithm to derive the recent star formation history in three fields in the bulge and disk of NGC 5102. In the disk fields, the recent star formation rate has declined monotonically and is now barely detectable, but a starburst is still in progress in the bulge and has added about 2 percent to the mass of the bulge over the last 200 Myr. Other studies of star formation in NGC 5102 indicate that about 20 percent of its stellar mass was added over the past Gyr. If this is correct, then much of the stellar mass of the bulge may have formed over this period. It seems likely that this star formation was fueled by the accretion of a gas-rich system with HI mass of about 2 x 10^9 Msol which has now been almost completely converted into stars. The large mass of recently formed stars and the blue colours of the bulge suggest that the current starburst, which is now fading, may have made a significant contribution to build the bulge of NGC 5102.Comment: 36 pages, 16 figures, accepted in A

The Metal-rich Globular Cluster NGC6553: Observations with WFPC2, STIS, and NICMOS

We present a HST study of the metal-rich globular cluster NGC6553 using WFPC2, NICMOS and STIS. Our primary motivation is to calibrate the STIS broad-band LP magnitude against $V_{555}$ and $I_{814}$ magnitudes for stars of known metallicity and absolute (visual) magnitude, for application to our study of LMC globular clusters. NGC6553 has been shown in earlier studies to have a very unusual colour-magnitude diagram, so we also use our data to investigate the reddening, distance, luminosity function and structure of this cluster. We deduce a higher metallicity and smaller distance modulus than did some previous studies, but emphasise that very large patchy extinction on small angular scales prohibits accurate determination of the parameters of this cluster. The horizontal branch of NGC6553 in ($V,V-I$) is tilted at an angle close to that of the reddening vector. We show that extinction does not, however, explain the tilt, which is presumably a metallicity effect. The colour-magnitude diagram shows an apparent second turnoff some 1.5 magnitudes fainter than that of the cluster. We show that this is most likely the background Galactic bulge: however, in that case, the colour-magnitude diagram of NGC6553 is not a good match to that of the field bulge population. The cluster is probably more metal-rich than is the mean field bulge star.Comment: 29 pages (Latex), 13 figs (PS, in document), 10 figs (JPEG format, outside document, degraded from original to save download time), accepted for pub. in A

Dynamics of the Galactic Bulge using Planetary Nebulae

Evidence for a bar at the center of the Milky Way triggered a renewed enthusiasm for dynamical modelling of the Galactic bar-bulge. Our goal is to compare the kinematics of a sample of tracers, planetary nebulae, widely distributed over the bulge with the corresponding kinematics for a range of models of the inner Galaxy. Three of these models are N-body barred systems arising from the instabilities of a stellar disk (Sellwood, Fux and Kalnajs), and one is a Schwarzschild system constructed to represent the 3D distribution of the COBE/DIRBE near-IR light and then evolved as an N-body system for a few dynamical times (Zhao). For the comparison of our data with the models, we use a new technique developed by Saha (1998). The procedure finds the parameters of each model, i.e. the solar galactocentric distance R_o in model units, the orientation angle phi, the velocity scale (in km/s per model unit), and the solar tangential velocity which best fit the data.Comment: 48 pages (Latex), 30 figures (PS), accepted for pub. in A

Assessing the evolution of primary healthcare organizations and their performance (2005-2010) in two regions of Québec province: Montréal and Montérégie

<p>Abstract</p> <p>Background</p> <p>The Canadian healthcare system is currently experiencing important organizational transformations through the reform of primary healthcare (PHC). These reforms vary in scope but share a common feature of proposing the transformation of PHC organizations by implementing new models of PHC organization. These models vary in their performance with respect to client affiliation, utilization of services, experience of care and perceived outcomes of care.</p> <p>Objectives</p> <p>In early 2005 we conducted a study in the two most populous regions of Quebec province (Montreal and Montérégie) which assessed the association between prevailing models of primary healthcare (PHC) and population-level experience of care. The <b>goal </b>of the present research project is to track the <it>evolution </it>of PHC organizational models and their relative performance through the reform process (from 2005 until 2010) and to assess factors at the organizational and contextual levels that are associated with the transformation of PHC organizations and their performance.</p> <p>Methods/Design</p> <p>This study will consist of three interrelated surveys, hierarchically nested. The first survey is a population-based survey of randomly-selected adults from two populous regions in the province of Quebec. This survey will assess the current affiliation of people with PHC organizations, their level of utilization of healthcare services, attributes of their experience of care, reception of preventive and curative services and perception of unmet needs for care. The second survey is an organizational survey of PHC organizations assessing aspects related to their vision, organizational structure, level of resources, and clinical practice characteristics. This information will serve to develop a taxonomy of organizations using a mixed methods approach of factorial analysis and principal component analysis. The third survey is an assessment of the organizational context in which PHC organizations are evolving. The five year prospective period will serve as a natural experiment to assess contextual and organizational factors (in 2005) associated with migration of PHC organizational models into new forms or models (in 2010) and assess the impact of this evolution on the performance of PHC.</p> <p>Discussion</p> <p>The results of this study will shed light on changes brought about in the organization of PHC and on factors associated with these changes.</p

Deep colour-magnitude diagrams of LMC field stars imaged with HST

We present deep photometry …V < ~26† in V and I bands obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope for 7 fields ~5◦ away from the Large Magellanic Cloud centre. The fields contain, typically, 2000 stars each. Isochrones were fitted to the colour–magnitude diagrams in order to identify different star populations in these fields. An old population …(t > 10 Gyr†) has been found in all fields. Some events of enhanced star formation, with ages between 2 and 4 Gyr, were identified in the fields localized in the north to north-west regions. Luminosity functions of low-mass stars were also obtained for all fields. Kolmogorov Smirnov test results suggest differences smaller than 30 per cent in the mixture of stellar populations contributing to the fields. Finally, density profiles were derived for old and intermediate-age stars. The former shows a slightly steeper decline than the latter