Mg I emission lines at 12 and 18 micrometer in K giants

The solar Mg I emission lines at 12 micrometer have already been observed and analyzed well. Previous modeling attempts for other stars have, however, been made only for Procyon and two cool evolved stars, with unsatisfactory results for the latter. We present high-resolution observational spectra for the K giants Pollux, Arcturus, and Aldebaran, which show strong Mg I emission lines at 12 micrometer as compared to the Sun. We also present the first observed stellar emission lines from Mg I at 18 micrometer and from Al I, Si I, and presumably Ca I at 12 micrometer. To produce synthetic line spectra, we employ standard non-LTE modeling for trace elements in cool stellar photospheres. We compute model atmospheres with the MARCS code, apply a comprehensive magnesium model atom, and use the radiative transfer code MULTI to solve for the magnesium occupation numbers in statistical equilibrium. We successfully reproduce the observed Mg I emission lines simultaneously in the giants and in the Sun, but show how the computed line profiles depend critically on atomic input data and how the inclusion of energy levels with n > 9 and collisions with neutral hydrogen are necessary to obtain reasonable fits.Comment: 9 pages, 6 figures, accepted for publication in Astronomy & Astrophysic

The impact of nebular emission on the broadband fluxes of high-redshift galaxies

A substantial fraction of the light emitted from young or star-forming galaxies at ultraviolet to near-infrared wavelengths comes from the ionized interstellar medium in the form of emission lines and a nebular continuum. At high redshifts, star formation rates are on average higher and stellar populations younger than in the local Universe. Both of these effects act to boost the impact of nebular emission on the overall spectrum of galaxies. Even so, the broadband fluxes and colours of high-redshift galaxies are routinely analyzed under the assumption that the light observed originates directly from stars. Here, we assess the impact of nebular emission on broadband fluxes in Johnson/Cousins BVRIJHK, Sloan Digital Sky Survey griz and Spitzer IRAC/MIPS filters as a function of observed redshift (up to z=15) for galaxies with different star formation histories. We find that nebular emission may account for a non-negligible fraction of the light received from high-redshift galaxies. The ages and masses inferred for such objects through the use of spectral evolutionary models that omit the nebular contribution are therefore likely to contain systematic errors. We argue that a careful treatment of the nebular component will be essential for the interpretation of the rest-frame ultraviolet-to-infrared properties of the first galaxies formed, like the ones expected to be detected with the James Webb Space Telescope.Comment: 5 pages, 3 figures, accepted for publication in ApJ

The development of a “holistic” model incorporating business strategy formulation with IdM strategy formulation

Identity management (IdM) not only improves the process of creating and maintaining digital identities across the business systems, but, if implemented successfully it can contribute to the strengthening and positioning of the business for success. In order to lead successful IdM implementation organizations need to step back and determine a course of action that would solve enterprise-wide issues. Short-sighted actions can lead to confusion, unnecessary expenses and the delay of beneficial results. This paper presents guidelines for application of strategic management principles regarding IdM implementation. By gathering and interpreting information from a real life case study on how a typical large South African business organization approached its IdM implementation, a theoretical model incorporating IdM implementation planning within business strategy formulation is proposed. This study results reveals five important guideline steps regarding IdM implementation

A detector for continuous measurement of ultra-cold atoms in real time

We present the first detector capable of recording high-bandwidth real time atom number density measurements of a Bose Einstein condensate. Based on a two-color Mach-Zehnder interferometer, our detector has a response time that is six orders of magnitude faster than current detectors based on CCD cameras while still operating at the shot-noise limit. With this minimally destructive system it may be possible to implement feedback to stabilize a Bose-Einstein condensate or an atom laser.Comment: 3 pages, 3 figures, submitted to optics letter

The ORGAN Experiment: An axion haloscope above 15 GHz

We present first results and future plans for the Oscillating Resonant Group AxioN (ORGAN) experiment, a microwave cavity axion haloscope situated in Perth, Western Australia designed to probe for high mass axions motivated by several theoretical models. The first stage focuses around 26.6 GHz in order to directly test a claimed result, which suggests axions exist at the corresponding mass of $110~\mu$eV. Later stages will move to a wider scan range of 15-50 GHz ($60-210~\mu$eV). We present the results of the pathfinding run, which sets a limit on $g_{a\gamma\gamma}$ of $2.02\times 10^{-12}$eV$^{-1}$ at 26.531 GHz, or 110~$\mu$eV, in a span of 2.5 neV (shaped by the Lorentzian resonance) with $90 \%$ confidence. Furthermore, we outline the current design and future strategies to eventually attain the sensitivity to search for well known axion models over the wider mass range.Comment: 15 pages, 5 figures. V2: As published in Physics of Dark Univers

A Causal Algebra for Liouville Exponentials

A causal Poisson bracket algebra for Liouville exponentials on a cylinder is derived using an exchange algebra for free fields describing the in and out asymptotics. The causal algebra involves an even number of space-time points with a minimum of four. A quantum realisation of the algebra is obtained which preserves causality and the local form of non-equal time brackets.Comment: 10 page

Labor Law, Industrial Relations and Employee Choice: The State of the Workplace in the 1990s: Hearings of the Commission on the Future of Worker-Management Relations, 1993-94

Block, Beck and Kruger present detailed examples from the testimony given during the Commission on the Future of Worker-Management Relations (commonly called the Dunlop Commission) national and regional hearings. The Commission, by hearing from a wide range of stakeholders, sought to define the state of industrial relations and labor law in the U.S. during the 1990s. Because the Commission\u27s final reports were concerned with policy matters, they only briefly summarized the testimony. This volume draws deeply from the testimony, citing many examples that clearly illustrate the wide variety of relationships between workers and management today. In addition, it shows how the interpretation of labor law has changed over the decades.https://research.upjohn.org/up_press/1072/thumbnail.jp

Epidemiology of acute spinal cord injuries in the Groote Schuur Hospital Acute Spinal Cord Injury (GSH ASCI) Unit, Cape Town, South Africa, over the past 11 years

Background. Spinal cord injury (SCI) is devastating to both patient and society, with acute management and ongoing care being extremely expensive. Few epidemiological data are available on SCIs in South Africa (SA).Objectives. To identify the epidemiological profile of SCI patients at Groote Schuur Hospital (GSH), Cape Town, SA, and identify seasonal trends and peak periods. As the majority of the injuries are preventable, these data are important to develop prevention strategies. Methods. A retrospective review of prospectively collected data was conducted on all patients admitted to the Acute Spinal Cord Injury (ASCI) Unit at GSH from 1 April 2003 to 31 March 2014. All cases registered on a prospectively maintained database were included in the study.Results. The total number of patients admitted to the ASCI Unit was 2 042, with an average of 185 admissions per year. The male/female ratio was 5.25:1. The 21 - 30-year-old age category was the largest, comprising 33.5% of the patients. The most prevalent cause of injury was motor vehicle accidents (44.6%), followed by violence-related injuries (27.2%). Thirty-two point two percent of patients needed ventilatory support, and 91.5% of mechanically ventilated patients were successfully weaned. December was the busiest month in the unit. In patients in whom neurological deficit was incomplete, the average motor function improvement was 16.0%.Conclusions. Data capturing and analysis of SCIs should be encouraged in SA to guide management and prevention strategies, and to optimise outcomes. This study establishes the ASCI Unit at GSH to be one of the key role players in acute SCI management in SA