The composition of HB stars : RR Lyrae variables

We used moderately high-resolution, high S/N spectra to study the chemical composition of 10 field ab-type RR Lyrae stars. A new temperature scale was determined from literature Infrared Flux Method measures of subdwarfs and the Kurucz (1992) model atmospheres, and used to calibrate colors for both dwarfs and RR Lyraes. The applicability of Kurucz (1992) model atmospheres in the analysis of RR Lyraes at minimum light was analyzed: we found that they are able to reproduce colors, excitation and ionization equilibria as well as the wings of Halpha. We derived abundances for 21 species. The metal abundances of the program stars span the range -2.50<[Fe/H]<+0.17$. Lines of most elements are found to form in LTE conditions. Fe lines satisfy very well the excitation and ionization equilibria. RR Lyraes share the typical abundance pattern of other stars of similar [Fe/H]: alpha-elements are overabundant by about 0.4dex and Mn is underabundant by about 0.6dex in stars with [Fe/H]<-1. Significant departures from LTE are found only for a few species. We used our new [Fe/H] abundances, as well as values from Butler and coworkers (corrected to our system), and from high resolution spectroscopy of globular clusters giants, to obtain a new calibration of the DeltaS index: [Fe/H]= -0.194(\pm 0.011)DeltaS -0.08(\pm 0.18) and to update the metallicity calibration of the Ca II K line index: [Fe/H]= 0.65(\pm 0.17)W'(K) -3.49(\pm 0.39). Finally, our new metallicity scale was used to revise the [Fe/H] dependence of the absolute magnitude of RR Lyrae stars, Mv: Mv = 0.20(\pm 0.03)[Fe/H] + 1.06(\pm 0.04).Comment: 59 pages, Latex using aaspp.sty, ps-files of text, tables (21) and figures (23) available from ftp://boas3.bo.astro.it/pub/gisella To appear in October 1995 Astronomical Journa

Caseloads and Salaries of Nephrology Social Workers by State, ESRD Network, and National Kidney Foundation Region: Summary Findings for 2007 and 2010

The Council of Nephrology Social Workers and the National Kidney Foundation conducted two national online surveys of nephrology social workers to assess caseload and salary trends by state, End-Stage Renal Disease Network, and National Kidney Foundation Region. Between 2007 and 2010, outpatient dialysis social workers experienced increases in mean case-load size from 73 to 79 (up 8.2%) for those employed 20–31 hours per week, 113 to 121 (up 7.1%) for those employed 32–40 hrs/wk, and 117 to 126 (up 7.7%) for those employed 40 hrs/wk. Increases in mean hourly wage were also reported across all three employment status groups for dialysis social workers: $25.03 to$28.16 per hour (up 12.5%) for 20–31 hrs/wk, $24.65 to$27.18 per hour (up 10.3%) for 32–40 hrs/wk, and $24.49 to$26.93 per hour (up 10%) for social workers employed 40 hrs/wk. For transplant social workers, mean hourly wage data showed increases across all three employment status groups: $22.96 to$27.74 per hour (up 20.8%) for those employed 20–31 hrs/wk, $25.19 to$29.56 per hour (up 17.3%) for those employed 32–40 hrs/wk, and $24.57 to$29.79 per hour (up 21.2%) for those employed 40 hrs/wk. In general, increases in caseload and hourly wage were found for nearly all states, End Stage Renal Disease Networks, and National Kidney Foundation Regions

Variable stars and stellar populations in Andromeda XXI: II. Another merged galaxy satellite of M31?

B and V time-series photometry of the M31 dwarf spheroidal satellite Andromeda XXI (And XXI) was obtained with the Large Binocular Cameras at the Large Binocular Telescope. We have identified 50 variables in And XXI, of which 41 are RR Lyrae stars (37 fundamental-mode RRab, and 4 first-overtone RRc, pulsators) and 9 are Anomalous Cepheids (ACs). The average period of the RRab stars ( = 0.64 days) and the period-amplitude diagram place And~XXI in the class of Oosterhoff II - Oosterhoff-Intermediate objects. From the average luminosity of the RR Lyrae stars we derived the galaxy distance modulus of (m-M)$_0$=$24.40\pm0.17$ mag, which is smaller than previous literature estimates, although still consistent with them within 1 $\sigma$. The galaxy color-magnitude diagram shows evidence for the presence of three different stellar generations in And~XXI: 1) an old ($\sim$ 12 Gyr) and metal poor ([Fe/H]=$-$1.7 dex) component traced by the RR Lyrae stars; 2) a slightly younger (10-6 Gyr) and more metal rich ([Fe/H]=$-$1.5 dex) component populating the red horizontal branch, and 3) a young age ($\sim$ 1 Gyr) component with same metallicity, that produced the ACs. Finally, we provide hints that And~XXI could be the result of a minor merging event between two dwarf galaxies.Comment: accepted for publications in Ap

New pulsational properties of eight "anomalous" RR Lyrae variables

CCD photometry in the V band is presented for 7 field RR Lyrae stars selected from a sample of eight variables which, according to data collected in the literature, are expected to be {\it ab}-type pulsators, to have short periods and hence high metallicity, and to be located at high {\it z} from the galactic plane. New periods and epochs are derived for them. The new periods are only slightly shorter than the values published on the last edition of the General Catalog of Variable Stars (GCVS4). Instead, in six cases our amplitude of the light variation is significantly smaller than that published on the GCVS4, and in at least three cases the actual pulsation appears to be in the first harmonic rather than in the fundamental mode. All the suggested {\it c}-type pulsators show variations in the amplitude and/or quite scattered light curves. Possible explanations are given. From a spectro-photometric analysis of the sample, only DL Com is confirmed to pulsate in the fundamental mode, to have short period, and to be located at relatively high {\it z}. A single object cannot be taken as evidence for a significant metal rich population at large distance from the galactic plane.Comment: 28 pages including text and tables, plain tex. Figures available through anonymous ftp at ftp://astbo3.bo.astro.it/pub/bap/files/ (get bap95-12-fig1.ps and bap95-12-figures.ps

Denture as an unexpected cause of obstructive jaundice

A 78-year-old woman who presented with jaundice and fever was referred from another hospital to our endoscopy unit. Her laboratory tests revealed a total bilirubin concentration of 11.7 µmol/L. Computed tomography (CT) scans revealed dilatation of the main biliary duct and the presence of a foreign body in the peripapillary area ([Fig. 1]). The appearance of the foreign body was suggestive of a denture, and the patient reported having involuntary ingested, 3 days previously, a denture that had been implanted many years ago. We performed an endoscopic retrograde cholangiopancreatography (ERCP), which revealed a protruding papilla with the appearance of an impacted stone. We started to perform a sphincterotomy using a precut needle-knife and completed it with a standard sphincterotome. After this, the denture was immediately expelled and allowed to pass into the duodenum ([Video 1]). In the following days, the patient’s total bilirubin level decreased and she was discharged home

Anomalous RR Lyrae stars(?). III. CM Leonis

Time series of B,V,I CCD photometry and radial velocity measurements from high resolution spectroscopy (R=30,000) covering the full pulsation cycle are presented for the field RR Lyrae star CM Leonis. The photometric data span a 6 year interval from 1994 to 1999, and allow us to firmly establish the pulsation mode and periodicity of the variable. The derived period P=0.361699 days (+/- 0.000001) is very close to the value published in the Fourth Edition of the General Catalogue of Variable Stars (P=0.361732 days). However, contrary to what was previously found, the amplitude and shape of the light curve qualify CM Leo as a very regular first overtone pulsator with a prominent hump on the rising branch of its multicolour light curves. According to an abundace analysis performed on three spectra taken near minimum light (0.42 < phase < 0.61), CM Leo is a metal-poor star with metal abundance [Fe/H]=-1.93 +/- 0.20. The photometric and radial velocity curves of CM Leo have been compared with the predictions of suitable pulsational models to infer tight constraints on the stellar mass, effective temperature, and distance modulus of the star. We derive a true distance modulus of CM Leo of (m-M)0=13.11 +/- 0.02 mag and a corresponding absolute magnitude of Mv=0.47 +/- 0.04. This absolute magnitude, once corrected for evolutionary and metallicity effects, leads to a true distance modulus of the Large Magellanic Cloud of (m-M)0=18.43 +/- 0.06 mag, in better agreement with the long astronomical distance scale.Comment: 14 pages, 10 figures, accepted for publication in MNRA

The ESO Slice Project (ESP) galaxy redshift survey: III. The Sample

The ESO Slice Project (ESP) is a galaxy redshift survey extending over about 23 square degrees, in a region near the South Galactic Pole. The survey is ~85% complete to the limiting magnitude b_J=19.4 and consists of 3342 galaxies with redshift determination. The ESP survey is intermediate between shallow, wide angle samples and very deep, one-dimensional pencil beams; the spanned volume is ~ 5 x 10^4 Mpc^3 at the sensitivity peak (z ~ 0.1). In this paper we present the description of the observations and of the data reduction, the ESP redshift catalogue and the analysis of the quality of the velocity determinations.Comment: 10 pages, 4 encapsulated figures, uses A&A LATEX; A&A Supplements in press (June 1998 issue

CU Comae: a new field double-mode RR Lyrae, the most metal poor discovered to date

We report the discovery of a new double-mode RR Lyrae variable (RRd) in the field of our Galaxy: CU Comae. CU Comae is the sixth such RRd identified to date and is the most metal-poor RRd ever detected. Based on BVI CCD photometry spanning eleven years of observations, we find that CU Comae has periods P0=0.5441641 +/-0.0000049d and P1=0.4057605 +/-0.0000018d. The amplitude of the primary (first-overtone) period of CU Comae is about twice the amplitude of the secondary (fundamental) period. The combination of the fundamental period of pulsation P0 and the period ratio of P1/P0=0.7457 places the variable on the metal-poor side of the Petersen diagram, in the region occupied by M68 and M15 RRd's. A mass of 0.83 solar masses is estimated for CU Comae using an updated theoretical calibration of the Petersen diagram. High resolution spectroscopy (R=30,000) covering the full pulsation cycle of CU Comae was obtained with the 2.7 m telescope of the Mc Donald Observatory, and has been used to build up the radial velocity curve of the variable. Abundance analysis done on the four spectra taken near minimum light (phase: 0.54 -- 0.71) confirms the metal poor nature of CU Comae, for which we derive [Fe/H]=-2.38 +/-0.20. This value places this new RRd at the extreme metal-poor edge of the metallicity distribution of the RR Lyrae variables in our Galaxy.Comment: 21 pages including 8 Tables, Latex, 11 Figures. Accepted for publication in The Astronomical Journal, October 2000 issu