The Tully-Fisher Relation and H_not

The use of the Tully-Fisher (TF) relation for the determination of the Hubble Constant relies on the availability of an adequate template TF relation and of reliable primary distances. Here we use a TF template relation with the best available kinematical zero-point, obtained from a sample of 24 clusters of galaxies extending to cz ~ 9,000 km/s, and the most recent set of Cepheid distances for galaxies fit for TF use. The combination of these two ingredients yields H_not = 69+/-5 km/(s Mpc). The approach is significantly more accurate than the more common application with single cluster (e.g. Virgo, Coma) samples.Comment: 10 pages, including 2 figures and 1 table; uses AAS LaTex. Submitted to ApJ Letter

The Metallicity-Luminosity Relation, Effective Yields, and Metal Loss in Spiral and Irregular Galaxies

I present results on the correlation between galaxy mass, luminosity, and metallicity for a sample of spiral and irregular galaxies having well-measured abundance profiles, distances, and rotation speeds. Additional data for low surface brightness galaxies from the literature are also included for comparison. These data are combined to study the metallicity-luminosity and metallicity-rotation speed correlations for spiral and irregular galaxies. The metallicity luminosity correlation shows its familiar form for these galaxies, a roughly uniform change in the average present-day O/H abundance of about a factor 100 over 11 magnitudes in B luminosity. However, the O/H - V(rot) relation shows a change in slope at a rotation speed of about 125 km/sec. At faster V(rot), there appears to be no relation between average metallicity and rotation speed. At lower V(rot), the metallicity correlates with rotation speed. This change in behavior could be the result of increasing loss of metals from the smaller galaxies in supernova-driven winds. This idea is tested by looking at the variation in effective yield, derived from observed abundances and gas fractions assuming closed box chemical evolution. The effective yields derived for spiral and irregular galaxies increase by a factor of 10-20 from V(rot) approximately 5 km/sec to V(rot) approximately 300 km/sec, asympotically increasing to approximately constant y(eff) for V(rot) > 150 km/sec. The trend suggests that galaxies with V(rot) < 100-150 km/sec may lose a large fraction of their SN ejecta, while galaxies above this value tend to retain metals.Comment: 40 pages total, including 7 encapsulated postscript figures. Accepted for publication in 20 Dec 2002 Ap

Sudden Collections Coordinators: When You Don’t Know What You Don’t Know

As new librarians enter the profession with varying levels of education and experience concerning library collection management, they may find themselves suddenly assigned the responsibility of coordinating collection activities within a subject area or for their entire library. From understanding terminology to working with acquisitions departments and from communicating with vendors to assessing resources, there is much to be learned in a short period of time. This paper will provide perspectives from five librarians at the George A. Smathers Libraries at the University of Florida (UF): the senior associate dean responsible for collections, the chair of the Acquisitions & Collections Services Department, an experienced collection coordinator, and two relatively new subject librarians who were recently asked to coordinate collection decisions for their respective areas (Humanities and Health Sciences). As one of the new collection coordinators came to subject librarianship from a specialized academic background and the other from a degree in library science, both newly promoted collection coordinators will present the unique difficulties faced in coming to collection coordination from their different educational backgrounds. This paper will address the large learning curve required when suddenly promoted to collection coordinator, including the steps of building a strong connection with acquisitions, developing vendor relations, and tracking collection development at the department level, while making suggestions for learning more along the way

Suicidality in family caregivers of people with long-term illnesses and disabilities: A scoping review

This is the author accepted manuscript; the final version is available from Elsevier via the DOI in this record.An emerging body of international research suggests family caregivers may be a high-risk group for suicide, but the evidence has not been synthesised. Forty-eight peer-reviewed journal articles were included in this review, spanning low-, middle-, and high-income countries and a variety of illnesses and disabilities. The proportion of caregivers experiencing suicidal ideation ranged from 2.7% to 71%, with evidence of suicide attempts, deaths by suicide, and deaths by homicide-suicide also reported. Risk and protective factors varied across studies and there was little consideration of differences by caregiving relationship, type of illness/disability, or country. There is sufficient evidence to warrant concern for caregivers around the world and prompt action in policy and practice, but more rigorous research is required to draw clear, nuanced conclusions about risk and inform evidence-based prevention and intervention.National Institute for Health Research (NIHR)University of BristolWeston NHS Foundation Trus

Warm Molecular Gas in Dwarf Starburst Galaxies: CO(3-2) Observations

Eight dwarf starburst galaxies have been observed with the Caltech Submillimeter Observatory (CSO) telescope in the CO J= 3 - 2 transition. The galaxies observed are He 2-10, NGC 5253, NGC 1569, NGC 3077, Haro 2, Haro 3, II Zw 40 and Mrk 86; all but the last two are detected. The central regions of He 2-10 and NGC 5253 were mapped and a CO(2-1) spectrum of NGC 5253 was obtained. The error weighted mean CO(3-2)/CO(1-0) ratio of the detected galaxies is 0.60$\pm$0.06, which is virtually identical to what is found for starbursts in the nuclei of nearby spirals, and suggests that the molecular gas is optically thick, warm (T$_{k}>$20 K), and moderately dense ($n_{H_{2}}\sim 10^{3-4} cm^{-3}$). The CO(3-2)/CO(1-0) ratio peaks at or close to the starburst in all cases. CO emission does not appear to be optically thin in these dwarfs, despite the low metallicity and intense radiation fields, which is probably because in order for CO to exist in detectable amounts it must be self-shielding and hence optically thick. Physical properties of the molecular clouds in these dwarf starbursts appear to be essentially the same as nearby spiral nuclei, with the possible exception that CO is more confined to the cloud cores.Comment: 21 pages, 8 figures; Accepted for publication by the Astronomical Journa

Oxygen and nitrogen abundances in nearby galaxies. Correlations between oxygen abundance and macroscopic properties

We performed a compilation of more than 1000 published spectra of HII regions in spiral galaxies. The oxygen and nitrogen abundances in each HII region were recomputed in a homogeneous way, using the P-method. The radial distributions of oxygen and nitrogen abundances were derived. The correlations between oxygen abundance and macroscopic properties are examined. There is a significant difference between the L-Z relationship obtained here and that based on the oxygen abundances determined through the R_23-calibrations. The oxygen abundance of NGC 5457 recently determined using direct measurements of Te (Kennicutt, Bresolin & Garnett 2003) agrees with the L-Z relationship derived here, but is in conflict with the L-Z relationship derived with the R_23-based oxygen abundances. The obtained L-Z relation for spirals is compared to that for irregulars. Our sample of galaxies shows evidence that the slope of the O/H-M_B relationship for spirals is slightly more shallow than that for irregulars. The effective oxygen yields were estimated for spiral and irregular galaxies. The effective oxygen yield increases with increasing luminosity from M_B=-11 to M_B=-18 (or with increasing rotation velocity from Vrot=10 km/s to Vrot=100 km/s) and then remains approximately constant. Irregular galaxies from our sample have effective oxygen yields lowered by a factor of 3 at maximum, i.e. irregular galaxies usually keep at least 1/3 of the oxygen they manufactured during their evolution.Comment: Accepted for publication in Astronomy and Astrophysics (Figures 2-5, Tables 2,6 and Appendix will only be published in the electronic version of the Journal

Absorption-line strengths of 18 late-type spiral galaxies observed with SAURON

The definitive version is available at www.blackwell-synergy.com. Copyright Blackwell Publishing DOI : 10.1111/j.1365-2966.2007.12121.xWe present absorption line-strength maps for a sample of 18 Sb-Sd galaxies observed using the integral-field spectrograph SAURON operating at the William Herschel Telescope on La Palma, as part of a project devoted to the investigation of the kinematics and stellar populations of late-type spirals, a relatively unexplored field. The SAURON spectral range allows the measurement of the Lick/IDS indices Hβ, Fe5015 and Mgb, which can be used to estimate the stellar population parameters.We present here the two-dimensional line-strength maps for each galaxy. From the maps, we learn that late-type spiral galaxies tend to have high Hβ and low Fe5015 andMgb values, and that the Hβ index has often a positive gradient over the field, while the metal indices peak in the central region. We investigate the relations between the central line-strength indices and their correlations with morphological type and central velocity dispersion, and compare the observed behaviour with that for ellipticals, lenticulars and early-type spirals from the SAURON survey. We find that our galaxies lie below the Mg - σ relation determined for elliptical galaxies and that the indices show a clear trend with morphological type. From the line-strength maps we calculate age, metallicity and abundance ratio maps via a comparison with model predictions; we discuss the results from a one-SSP (Single Stellar Population) approach and from a two-SSP approach, considering the galaxy as a superposition of an old ( 13 Gyr) and a younger (age 6 5 Gyr) population.We confirm that late-type galaxies are generally younger and more metal poor than ellipticals and have abundance ratios closer to solar values. We also explore a continuous star formation scenario, and try to recover the star formation history using the evolutionarymodels of Bruzual & Charlot (2003), assuming constant or exponentially declining star formation rate (SFR). In this last case, fixing the galaxy age to 10 Gyr, we find a correlation between the e-folding time-scale τ of the starburst and the central velocity dispersion, in the sense that more massive galaxies tend to have shorter τ, suggesting that the star formation happened long ago and has now basically ended, while for smaller objects with larger values of τ it is still active now.Peer reviewe

Abortive infection by bacteriophage Me1 of Escherichia coli K12 strains bearing the plasmid ColV, I-K94

Bacteriophage Me1 is unable to grow on Escherichia coli strains harbouring the ColV,I-K94 plasmid. The nature of this inhibition was investigated, and it was found not to be due to restriction, superinfection exclusion or receptor-mediated resistance, but to be a new example of plasmid-mediated abortive infection. Investigation of events occurring during abortive Me1 infection revealed some differences from previously described cases, especially with regard to late protein synthesis, which did occur, albeit showing abnormal amounts of some proteins. No major differences were observed in membrane permeability of productively and abortively infected cells. Phage-directed DNA synthesis was reduced in abortively infected cells. Comparative studies of Me1 and T4 revealed a striking similarity despite some minor differences

Auto-ignition of fuels using highly stabilised hydrogen peroxide

Due to the toxic nature of common high-performance rocket propellant combinations (such as monomethyl-hydrazine/di-nitrogen tetroxide), there is now growing interest in so-called 'green' propellants. In response to this, and in the continuation of existing research, a small demonstration bi-propellant rocket-engine was designed, built and tested using homogeneous catalysis of highly stabilised hydrogen peroxide. An investigation into suitable fuels was conducted, and candidates selected. Auto-ignition was successfully achieved, demonstrating the robustness of the propellant combination