Establishing an analogue population for the most distant galaxies

Lyman break analogues (LBAs) are local galaxies selected to match a more distant (usually z~3) galaxy population in luminosity, UV-spectral slope and physical characteristics, and so provide an accessible laboratory for exploring their properties. However, as the Lyman break technique is extended to higher redshifts, it has become clear that the Lyman break galaxies (LBGs) at z~3 are more massive, luminous, redder, more extended and at higher metallicities than their z~5 counterparts. Thus extrapolations from the existing LBA samples (which match z=3 properties) have limited value for characterising z>5 galaxies, or inferring properties unobservable at high redshift. We present a new pilot sample of twenty-one compact star forming galaxies in the local (0.05<z<0.25) Universe, which are tuned to match the luminosities and star formation volume densities observed in z>~5 LBGs. Analysis of optical emission line indices suggests that these sources have typical metallicities of a few tenths Solar (again, consistent with the distant population). We also present radio continuum observations of a subset of this sample (13 sources) and determine that their radio fluxes are consistent with those inferred from the ultraviolet, precluding the presence of a heavily obscured AGN or significant dusty star formation.Comment: 13 pages, MNRAS accepte

Physical properties of local star-forming analogues toz∼ 5 Lyman break galaxies

Intense, compact, star-forming galaxies are rare in the local Universe but ubiquitous at high redshift. We interpret the 0.1-22 μm spectral energy distributions (SED) of a sample of 180 galaxies at 0.05 < z < 0.25 selected for extremely high surface densities of inferred star formation in the ultraviolet. By comparison with well-established stellar population synthesis models we find that our sample comprises young (∼ 60 - 400 Myrs), moderate mass (∼6 × 109 M⊙) star-forming galaxies with little dust extinction (mean stellar continuum extinction Econt(B − V) ∼ 0.1) and find star formation rates of a few tens of Solar masses per year. We use our inferred masses to determine a mean specific star formation rate for this sample of ∼10−9 yr−1, and compare this to the specific star formation rates in distant Lyman break galaxies (LBGs), and in other low redshift populations. We conclude that our sample's characteristics overlap significantly with those of the z ∼ 5 LBG population, making ours the first local analogue population well tuned to match those high redshift galaxies. We consider implications for the origin and evolution of early galaxies

Large Scale Structure traced by Molecular Gas at High Redshift

We present observations of redshifted CO(1-0) and CO(2-1) in a field containing an overdensity of Lyman break galaxies (LBGs) at z=5.12. Our Australia Telescope Compact Array observations were centered between two spectroscopically-confirmed z=5.12 galaxies. We place upper limits on the molecular gas masses in these two galaxies of M(H_2) <1.7 x 10^10 M_sun and <2.9 x 10^9 M_sun (2 sigma), comparable to their stellar masses. We detect an optically-faint line emitter situated between the two LBGs which we identify as warm molecular gas at z=5.1245 +/- 0.0001. This source, detected in the CO(2-1) transition but undetected in CO(1-0), has an integrated line flux of 0.106 +/- 0.012 Jy km/s, yielding an inferred gas mass M(H_2)=(1.9 +/- 0.2) x 10^10 M_sun. Molecular line emitters without detectable counterparts at optical and infrared wavelengths may be crucial tracers of structure and mass at high redshift.Comment: 4 pages, accepted for publication in ApJ Letter

Changing trends in residents-as-teachers across graduate medical education

BACKGROUND: Teaching residents how to teach is a critical part of residents' training in graduate medical education (GME). The purpose of this study was to assess the change in resident-as-teacher (RaT) instruction in GME over the past 15 years in the US. METHODS: We used a quantitative and qualitative survey of all program directors (PDs) across specialties. We compared our findings with a previous work from 2000-2001 that studied the same matter. Finally, we qualitatively analyzed PDs' responses regarding the reasons for implementing and not implementing RaT instruction. RESULTS: Two hundred and twenty-one PDs completed the survey, which yields a response rate of 12.6%. Over 80% of PDs implement RaT, an increase of 26.34% compared to 2000-2001. RaT instruction uses multiple methods with didactic lectures reported as the most common, followed by role playing in simulated environments, then observing and giving feedback. Residents giving feedback, clinical supervision, and bedside teaching were the top three targeted skills. Through our qualitative analysis we identified five main reasons for implementing RaT: teaching is part of the residents' role; learners desire formal RaT training; regulatory bodies require RaT training; RaT improves residents' education; and RaT prepares residents for their current and future roles. CONCLUSION: The use of RaT instruction has increased significantly in GME. More and more PDs are realizing its importance in the residents' formative training experience. Future studies should examine the effectiveness of each method for RaT instruction

Radio observations confirm young stellar populations in local analogues to z ~5 Lyman break galaxies

We present radio observations at 1.5 GHz of 32 local objects selected to reproduce the physical properties of z .5 star-forming galaxies. We also report non-detections of five such sources in the sub-millimetre. We find a radio-derived star formation rate which is typically half that derived from Hα emission for the same objects. These observations support previous indications that we are observing galaxies with a young dominant stellar population, which has not yet established a strong supernova-driven synchrotron continuum. We stress caution when applying star formation rate calibrations to stellar populations younger than 100 Myr. We calibrate the conversions for younger galaxies, which are dominated by a thermal radio emission component. We improve the size constraints for these sources, compared to previous unresolved ground-based optical observations. Their physical size limits indicate very high star formation rate surface densities, several orders of magnitude higher than the local galaxy population. In typical nearby galaxies, this would imply the presence of galaxy-wide winds. Given the young stellar populations, it is unclear whether a mechanism exists in our sources that can deposit sufficient kinetic energy into the interstellar medium to drive such outflows

Morphologies and Color Gradients of Luminous Evolved Galaxies at z~1.5

We have examined in detail the morphologies of seven z~1.5 passively evolving luminous red galaxies using high resolution HST NICMOS and ACS imaging data. Almost all of these galaxies appear to be relaxed systems, with smooth morphologies at both rest-frame UV and visible wavelengths. Previous results from spectral synthesis modeling favor a single burst of star formation more than 1 Gyr before the observed epoch. The prevalence of old stellar populations, however, does not correlate exclusively with early-type morphologies as it does in the local universe; the light profiles for some of these galaxies appear to be dominated by massive exponential disks. This evidence for massive old disks, along with the apparent uniformity of stellar age across the disk, suggests formation by a mechanism better described as a form of monolithic collapse than as a hierarchical merger. These galaxies could not have undergone a single major merging event since the bulk of their stars were formed, more than 1 Gyr earlier. There is at least one case, however, that appears to be undergoing a "dry merger", which may be an example of the process that converts these unusual galaxies into the familiar spheroids that dominate galaxies comprising old stellar populations at the present epoch.Comment: 16 pages, 9 figures (8 in color), accepted for publication in Ap

Inequalities in the incidence of cervical cancer in South East England 2001–2005: an investigation of population risk factors

BACKGROUND: The incidence of cervical cancer varies dramatically, both globally and within individual countries. The age-standardised incidence of cervical cancer was compared across primary care trusts (PCTs) in South East England, taking into account the prevalence of known behavioural risk factors, screening coverage and the deprivation of the area. METHODS: Data on 2,231 cases diagnosed between 2001 and 2005 were extracted from the Thames Cancer Registry, and data on risk factors and screening coverage were collated from publicly available sources. Age-standardised incidence rates were calculated for each PCT using cases of squamous cell carcinoma in the screening age group (25-64 years). RESULTS: The age-standardised incidence rate for cervical cancer in South East England was 6.7 per 100,000 population (European standard) but varied 3.1 fold between individual PCTs. Correlations between the age-standardised incidence rate and smoking prevalence, teenage conception rates, and deprivation were highly significant at the PCT level (p < 0.001). However, screening coverage was not associated with the incidence of cervical cancer at the PCT level. Poisson regression indicated that these variables were all highly correlated and could not determine the level of independent contribution at a population level. CONCLUSION: There is excess disease burden within South East England. Significant public health gains can be made by reducing exposure to known risk factors at a population level

Measuring service quality of international tennis coach education courses

Customer satisfaction with the quality of sport services contributes significantly to the sustained competitiveness of sport organisations, and customer retention. This study measured the perceived service quality of the International Tennis Federation (ITF) Starter-Beginner coach education courses. A purposive sample of four courses and 56 tennis coaches was drawn. A precourse and post course SERVQUAL questionnaire together with a biographical questionnaire were administered. The findings of the current study suggest that tennis coaches are dissatisfied with four of the five SERVQUAL dimensions of service quality namely the reliability of the services, the responsiveness of the ITF as service provider, the tangibles of the course as well as the empathy of the ITF. Tennis coaches expressed overall satisfaction in the service dimension of assurance of service users. Satisfaction with service quality differed across the four different geographical course locations suggesting dissatisfaction with personal interaction between head tutors and participants. This study should be regarded as exploratory research in the area of tennis coach education service quality. Further research should determine the reliability and validity of the SERVQUAL instrument in sport coach education contexts.http://www.ajol.info/journal_index.php?jid=153&ab=ajpherd2016-03-30am201