We present the size evolution of passively evolving galaxies at z ~ 2 identified in Wide-Field Camera 3 imaging from the Early Release Science program. Our sample was constructed using an analog to ...the passive BzK galaxy selection criterion, which isolates galaxies with little or no ongoing star formation at z > ~ 1.5. We identify 30 galaxies in ~40 arcmin super(2) to H < 25 mag. By fitting the 10-band Hubble Space Telescope photometry from 0.22 mu m < ~ lambda sub(obs) < ~ 1.6 mu m with stellar population synthesis models, we simultaneously determine photometric redshift, stellar mass, and a bevy of other population parameters. Based on the six galaxies with published spectroscopic redshifts, we estimate a typical redshift uncertainty of ~0.033(1 + z). We determine effective radii from Sersic profile fits to the H-band image using an empirical point-spread function. By supplementing our data with published samples, we propose a mass-dependent size evolution model for passively evolving galaxies, where the most massive galaxies (Mlow * ~ 10 super(11) M) undergo the strongest evolution from z ~ 2 to the present. Parameterizing the size evolution as (1 + z) super(- alpha ), we find a tentative scaling of alpha approx = (- 0.6 + or - 0.7) + (0.9 + or - 0.4)log(Mlow */10 super(9) M sub(middot in circle)), where the relatively large uncertainties reflect the poor sampling in stellar mass due to the low numbers of high-redshift systems. We discuss the implications of this result for the redshift evolution of the Mlow *-R sub(e) relation for red galaxies.
We combine new high sensitivity ultraviolet (UV) imaging from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) with existing deep HST/Advanced Camera for Surveys optical images from ...the Great Observatories Origins Deep Survey (GOODS) program to identify UV-dropouts, which are Lyman break galaxy (LBG) candidates at z {approx_equal} 1-3. These new HST/WFC3 observations were taken over 50 arcmin{sup 2} in the GOODS-South field as a part of the Early Release Science program. The uniqueness of these new UV data is that they are observed in three UV/optical (WFC3 UVIS) channel filters (F225W, F275W, and F336W), which allows us to identify three different sets of UV-dropout samples. We apply Lyman break dropout selection criteria to identify F225W-, F275W-, and F336W-dropouts, which are z {approx_equal} 1.7, 2.1, and 2.7 LBG candidates, respectively. We use multi-wavelength imaging combined with available spectroscopic and photometric redshifts to carefully access the validity of our UV-dropout candidates. Our results are as follows: (1) these WFC3 UVIS filters are very reliable in selecting LBGs with z {approx_equal} 2.0, which helps to reduce the gap between the well-studied z {approx}> 3 and z {approx} 0 regimes; (2) the combined number counts with average redshift z {approx_equal} 2.2 agree very well with the observed change in the surface densities as a function of redshift when compared with the higher redshift LBG samples; and (3) the best-fit Schechter function parameters from the rest-frame UV luminosity functions at three different redshifts fit very well with the evolutionary trend of the characteristic absolute magnitude, M*, and the faint-end slope, {alpha}, as a function of redshift. This is the first study to illustrate the usefulness of the WFC3 UVIS channel observations to select z {approx}< 3 LBGs. The addition of the new WFC3 on the HST has made it possible to uniformly select LBGs from z {approx_equal} 1 to z {approx_equal} 9 and significantly enhance our understanding of these galaxies using HST sensitivity and resolution.
Background
The aim was to describe the management of benign gallbladder disease and identify characteristics associated with all‐cause 30‐day readmissions and complications in a prospective ...population‐based cohort.
Methods
Data were collected on consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing all‐cause 30‐day readmissions and complications were analysed by means of multilevel, multivariable logistic regression modelling using a two‐level hierarchical structure with patients (level 1) nested within hospitals (level 2).
Results
Data were collected on 8909 patients undergoing cholecystectomy from 167 hospitals. Some 1451 cholecystectomies (16·3 per cent) were performed as an emergency, 4165 (46·8 per cent) as elective operations, and 3293 patients (37·0 per cent) had had at least one previous emergency admission, but had surgery on a delayed basis. The readmission and complication rates at 30 days were 7·1 per cent (633 of 8909) and 10·8 per cent (962 of 8909) respectively. Both readmissions and complications were independently associated with increasing ASA fitness grade, duration of surgery, and increasing numbers of emergency admissions with gallbladder disease before cholecystectomy. No identifiable hospital characteristics were linked to readmissions and complications.
Conclusion
Readmissions and complications following cholecystectomy are common and associated with patient and disease characteristics.
Emergency rather than delayed cholecystectomy
We present an observational picture of the HH 409 bipolar outflow including the detection of six previously unreported Herbig-Haro knots from the Herbig Ae star HD 163296. This study combines seven ...years of data from ground-based Fabry-Perot and HST coronagraphic imagery, as well as HST long-slit spectral imagery. The redshifted counterjet includes a chain of six Herbig-Haro knots spanning >27" to the northeast (P.A. -42) of the source and has been active for >80 yr. The brightest knot in the counterjet is HH 409 C, a low-excitation bow shock with a shock velocity V sub(s) 650 km s super(-1) and total space motion V sub(jet) -260 km s super(-1). The presence of additional knots in the counterjet beyond the bow shock may indicate precession of the jet axis. The blueshifted jet includes two closely spaced knots within 10" and a distant bow shock (-21") southwest (P.A. -223) of the source. The brightest knot in the jet is HH 409 A, a higher excitation more bullet-like shock with V sub(s) 690 km s super(-1) and V sub(jet) -360 km s super(-1). The average opening angles for both the jet and counterjet are similar, a sub(a) 62, and consistent with opening angles of lower mass T Tauri stars. The mass-loss rates in both lobes of the flow, despite the asymmetry of the knots, are also comparable, sub(out) 61.0 x 10 super(-8) M sub( )yr super(-1). This suggests that variations in the mass outflow rate are not more than a factor of 62.
Using HST ACS, we have obtained deep optical images reaching stars well below the oldest main-sequence turnoff in the spheroid, tidal stream, and outer disk of Andromeda. We have reconstructed the ...star formation history in these fields by comparing their color-magnitude diagrams to a grid of isochrones calibrated to Galactic globular clusters observed in the same bands. Each field exhibits an extended star formation history, with many stars younger than 10 Gyr but few younger than 4 Gyr. Considered together, the star counts, kinematics, and population characteristics of the spheroid argue against some explanations for its intermediate-age, metal-rich population, such as a significant contribution from stars residing in the disk or a chance intersection with the stream's orbit. Instead, it is likely that this population is intrinsic to the inner spheroid, whose highly disturbed structure is clearly distinct from the pressure-supported metal-poor halo that dominates farther from the galaxy's center. The stream and spheroid populations are similar, but not identical, with the stream's mean age being 61 Gyr younger; this similarity suggests that the inner spheroid is largely polluted by material stripped from either the stream's progenitor or similar objects. The disk population is considerably younger and more metal-rich than the stream and spheroid populations, but not as young as the thin-disk population of the solar neighborhood; instead, the outer disk of Andromeda is dominated by stars of age 4-8 Gyr, resembling the Milky Way's thick disk. The disk data are inconsistent with a population dominated by ages older than 10 Gyr and in fact do not require any stars older than 10 Gyr.
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