A Deep Survey of HI-Selected Galaxies: The Sample and the Data

In a 21 cm neutral hydrogen survey of approximately 55 sq deg out to a redshift of cz=8340 km/s, we have identified 75 extragalactic HI sources. These objects comprise a well-defined sample of extragalactic sources chosen by means that are independent of optical surface brightness selection effects. In this paper we describe the Arecibo survey procedures and HI data, follow-up VLA HI observations made of several unusual sources, and Kitt Peak B-, R-, and I-band photometry for nearly all of the galaxies. We have also gathered information for some of the optically detected galaxies within the same search volume. We examine how samples generated by different types of search techniques overlap with selection by HI flux. Only the least massive HI object, which is among the lowest mass HI sources previously found, does not have a clear optical counterpart, but a nearby bright star may hide low surface brightness emission. However the newly-detected systems do have unusual optical properties. Most of the 40 galaxies that were not previously identified in magnitude-limited catalogs appear to be gas-dominated systems, and several of these systems have HI mass-to-light ratios among the largest values ever previously found. These gas-dominated objects also tend to have very blue colors, low surface brightnesses, and no central bulges, which correlate strongly with their relative star-to-gas content.Comment: 48 pages, 10 figures, Figure 3 included as 3 separate JPG images. To appear in Ap J Supplement

Spectral Decomposition of Broad-Line AGNs and Host Galaxies

Using an eigenspectrum decomposition technique, we separate the host galaxy from the broad line active galactic nucleus (AGN) in a set of 4666 spectra from the Sloan Digital Sky Survey (SDSS), from redshifts near zero up to about 0.75. The decomposition technique uses separate sets of galaxy and quasar eigenspectra to efficiently and reliably separate the AGN and host spectroscopic components. The technique accurately reproduces the host galaxy spectrum, its contributing fraction, and its classification. We show how the accuracy of the decomposition depends upon S/N, host galaxy fraction, and the galaxy class. Based on the eigencoefficients, the sample of SDSS broad-line AGN host galaxies spans a wide range of spectral types, but the distribution differs significantly from inactive galaxies. In particular, post-starburst activity appears to be much more common among AGN host galaxies. The luminosities of the hosts are much higher than expected for normal early-type galaxies, and their colors become increasingly bluer than early-type galaxies with increasing host luminosity. Most of the AGNs with detected hosts are emitting at between 1% and 10% of their estimated Eddington luminosities, but the sensitivity of the technique usually does not extend to the Eddington limit. There are mild correlations among the AGN and host galaxy eigencoefficients, possibly indicating a link between recent star formation and the onset of AGN activity. The catalog of spectral reconstruction parameters is available as an electronic table.Comment: 18 pages; accepted for publication in A

A Theater Intervention to Prevent Teen Dating Violence for Mexican-American Middle School Students

Purpose To test a theater intervention designed to raise awareness of the dynamics and consequences of teen dating violence (TDV) and to facilitate creation of nonviolent responses to TDV among Latino and Latina adolescents. The intervention was based on Theater of the Oppressed, which advocates the use of theater methods to explore social issues and to allow audiences to experiment with problem-solving, thereby promoting change. Methods This study used a pretest–posttest, no control group, mixed-measures design to study 66 Mexican-American adolescents (mean age, 13.4 ± 5 years). Two plays containing subtle and overt signs of control and abuse were written and performed. Scripts were based on data from prior studies of TDV among Latino and Latina adolescents. At baseline, we measured sociodemographics, personal safety, and ethnic identity. Pre–post instruments measured acceptance of TDV, confidence to resolve conflicts nonviolently, and intentions to use nonviolent strategies to resolve conflict. We collected qualitative data via essay. Results At posttest, participants had less acceptance of TDV (t = −2.08; p \u3c .05), increased confidence to resolve conflicts nonviolently (t = 3.82; p \u3c .001), and higher intentions to use nonviolent strategies (t = 3.35; p = .001). We analyzed 20 essays. Qualitative results provided context for understanding participants\u27 changes in attitude, confidence, and nonviolent behavioral intentions. Conclusions This adaptation of Theater of the Oppressed was an effective way to interact with Latino adolescents. In a safe setting, participants vicariously experienced TDV, which facilitated self-reflection and cognitive rehearsal strategies to respond nonviolently to TDV

Organizational boundaries of medical practice: the case of physician ownership of ancillary services

Physician ownership of in-office ancillary services (IOASs) has come under increasing scrutiny. Advocates of argue that IOASs allow physicians to supervise the quality and coordination of care. Critics have argued that IOASs create financial incentives for physicians to increase ancillary service volume. In this paper we develop a conceptual framework to evaluate the tradeoffs associated with physician ownership of IOASs. There is some evidence supporting the existence of scope and transaction economies in IOASs. Improvement in flow and continuity of care are likely to generate scope economies and improvements in quality monitoring and reductions in consumer transaction costs are likely to generate transaction economies. Other factors include the capture of upstream and downstream profits, but these incentives are likely to be small compared to scope and transaction economies. Policy debates on the merits of IOASs should include an explicit assessment of these tradeoffs. This research was supported in part by funding from the American Association of Orthopaedic Surgeons (AAOS)

Exoplanet Catalogues

One of the most exciting developments in the field of exoplanets has been the progression from 'stamp-collecting' to demography, from discovery to characterisation, from exoplanets to comparative exoplanetology. There is an exhilaration when a prediction is confirmed, a trend is observed, or a new population appears. This transition has been driven by the rise in the sheer number of known exoplanets, which has been rising exponentially for two decades (Mamajek 2016). However, the careful collection, scrutiny and organisation of these exoplanets is necessary for drawing robust, scientific conclusions that are sensitive to the biases and caveats that have gone into their discovery. The purpose of this chapter is to discuss and demonstrate important considerations to keep in mind when examining or constructing a catalogue of exoplanets. First, we introduce the value of exoplanetary catalogues. There are a handful of large, online databases that aggregate the available exoplanet literature and render it digestible and navigable - an ever more complex task with the growing number and diversity of exoplanet discoveries. We compare and contrast three of the most up-to-date general catalogues, including the data and tools that are available. We then describe exoplanet catalogues that were constructed to address specific science questions or exoplanet discovery space. Although we do not attempt to list or summarise all the published lists of exoplanets in the literature in this chapter, we explore the case study of the NASA Kepler mission planet catalogues in some detail. Finally, we lay out some of the best practices to adopt when constructing or utilising an exoplanet catalogue.Comment: 14 pages, 6 figures. Invited review chapter, to appear in "Handbook of Exoplanets", edited by H.J. Deeg and J.A. Belmonte, section editor N. Batalh