MicroLux: high-precision timing of high-speed photometric observations

MicroLux is a GPS-based high precision and high speed timing add-on to the Calar Alto Lucky Imaging camera AstraLux. It allows timestamping of individual CCD exposures at frame rates of more than 1 kHz with an accuracy better than one microsecond with respect to the UTC timeframe. The system was successfully used for high speed observations of the optical pulse profile of the Crab pulsar in January and November 2007. I present the technical design concept of MicroLux as well as first results from these observations, in particular the reconstructed pulse profile of the pulsar.Comment: 8 pages, 6 figures, to appear in "Ground-based and Airborne Instrumentation for Astronomy II" SPIE conference, Marseille, 23-28 June 200

The benefits of discourse analysis for Human Resource Management

The objective of this article is to take a closer look at discourse analysis as a qualitative method of data collection, analysis and theory building in Human Resource Management. Working exclusively with audio or video recordings of authentic conversations and following a systematic methodological process, discourse analysis enables researchers to develop theoretical conclusions and models on HR topics. First, basic assumptions and tools of discourse analysis are presented. Special emphasis is put on the applied discourse analytical approach and potential benefits for research on Human Resource Management. Second, drawing on a research project carried out at the University of Bayreuth, an example is presented of how discourse analysis was used to investigate experience management. The project yielded a theoretical model that describes the communicative processes of experience transfer among expatriate managers. It reveals the particular challenges involved as well as strategies interactants use to cope with them. Being strictly action-oriented, the model is advantageous for deducing recommendations for Human Resource Development.Ziel dieses Artikels ist es, die Leistungen der Gesprächsanalyse als qualitative Methode der Datenerhebung, Auswertung und Theoriebildung im Personalmanagement aufzuzeigen. Die Gesprächsanalyse arbeitet ausschließlich mit Ton- und Videoaufnahmen authentischer Gespräche und folgt dabei einem systematischen methodischen Vorgehen, das es dem Forscher ermöglicht, theoretische Schlussforderungen und Modelle zu Personalmanagementthemen zu entwickeln. Zunächst werden grundlegende Annahmen und Werkzeuge der Gesprächsanalyse vorgestellt. Ein Schwerpunkt liegt auf der angewandten Gesprächsforschung und dem Nutzen für die Forschung im Bereich des Personalmanagements. Anhand eines Projekts an der Universität Bayreuth wird aufgezeigt, wie die Gesprächsanalyse genutzt werden kann, um Strategien des Erfahrungsmanagements zu erforschen. In dem Projekt wurde ein theoretisches Modell der kommunikativen Prozesse der Erfahrungsweitergabe unter Auslandsentsandten entwickelt. Es beschreibt die spezifischen Herausforderungen, die sich für Gesprächspartner ergeben, sowie Strategien, die sie zu ihrer Bewältigung verwenden. Das strikt handlungsorientierte Modell bietet eine gute Grundlage, um Empfehlungen für die Personalentwicklungspraxis abzuleiten

AstraLux: the Calar Alto Lucky Imaging Camera

AstraLux is the Lucky Imaging camera for the Calar Alto 2.2-m telescope, based on an electron-multiplying high speed CCD. By selecting only the best 1-10% of several thousand short exposure frames, AstraLux provides nearly diffraction limited imaging capabilities in the SDSS i' and z' filters over a field of view of 24x24 arcseconds. By choosing commercially available components wherever possible, the instrument could be built in short time and at comparably low cost. We present the instrument design, the data reduction pipeline, and summarise the performance and characteristicsComment: 12 pages, 7 figures, to appear in "Ground-based and Airborne Instrumentation for Astronomy II" SPIE conference, Marseille, 23-28 June 200

Examining the T Tauri system with SPHERE

Context. The prototypical low-mass young stellar object, T Tauri, is a well-studied multiple system with at least three components. Aims. We aim to explore the T Tau system with the highest spatial resolution, study the time evolution of the known components, and re-determine the orbital parameters of the stars. Methods. Near-infrared classical imaging and integral field spectrograph observations were obtained during the Science Verification of SPHERE, the new high-contrast imaging facility at the VLT. The obtained FWHM of the primary star varies between 0.050" and 0.059", making these the highest spatial resolution near-infrared images of the T Tauri system obtained to date. Results. Our near-infrared images confirm the presence of extended emission south of T Tau Sa, reported in the literature. New narrow-band images show, for the first time, that this feature shows strong emission in both the Br-{\gamma} and H2 1-0 S(1) lines. Broadband imaging at 2.27 {\mu}m shows that T Tau Sa is 0.92 mag brighter than T Tau Sb, which is in contrast to observations from Jan. 2014 (when T Tau Sa was fainter than Sb), and demonstrates that T Tau Sa has entered a new period of high variability. The newly obtained astrometric positions of T Tau Sa and Sb agree with orbital fits from previous works. The orbit of T Tau S (the center of gravity of Sa and Sb) around T Tau N is poorly constrained by the available observations and can be fit with a range of orbits ranging from a nearly circular orbit with a period of 475 years to highly eccentric orbits with periods up to 2.7*10^4 years. We also detected a feature south of T Tau N, at a distance of $144 \pm 3$ mas, which shows the properties of a new companion.Comment: Accepted by A&A Letter

The AstraLux large M dwarf survey

AstraLux is the Lucky Imaging camera for the Calar Alto 2.2-m telescope and the 3.5-m NTT at La Silla. It allows nearly diffraction limited imaging in the SDSS i' and z' bands of objects as faint as i'=15.5mag with minimum technical effort. One of the ongoing AstraLux observing programs is a binarity survey among late-type stars with spectral types K7 to M8, covering more than 1000 targets on the northern and southern hemisphere. The survey is designed to refine binarity statistics and especially the dependency of binarity fraction on spectral type. The choice of the SDSS i' and z' filters allows to obtain spectral type and mass estimates for resolved binaries. With an observing efficiency of typically 6 targets per hour we expect to complete the survey in mid-2009. Selected targets will be followed up astrometrically and photometrically, contributing to the calibration of the mass-luminosity relation at the red end of the main sequence and at visible wavelengths.Comment: 4 pages, 3 figures. To appear in proceedings of Cool Stars 15 conference, St. Andrews, 200

Schulische Suchtvereinbarung : ein Leitfaden

Suchtvereinbarungen sind Maßnahmen struktureller schulischer Suchtprävention und Teil des umfassenderen Arbeitsfeldes schulischer Gesundheitsförderung. Die Idee, das aus der betrieblichen Gesundheitsförderung stammende Konzept der Suchtvereinbarung für die schulische Suchtprävention nutzbar zu machen, kam ursprünglich aus der Schweiz und verbreitete sich von da aus rasch im deutschsprachigen Raum. In Baden-Württemberg sind seit Mitte der 90er Jahre schulische Suchtvereinbarungen entwickelt worden, häufig aus Anlass aktueller Vorkommnisse. In Hessen wurde die Idee erst etwas später aufgegriffen. Die erste schulische Suchtvereinbarung in Frankfurt am Main wurde von der Bergius-Schule, einer Beruflichen Schule (Fachrichtungen Chemie, Physik, Biologie, Wirtschaft und Verwaltung sowie Ernährung und Hauswirtschaft) entwickelt und Anfang 2004 endgültig in Kraft gesetzt. Als zweite Schule gab sich Anfang 2006 die Ludwig-Ehrhard-Schule eine Suchtvereinbarung, mehrere weitere Schulen sind auf dem Weg

Binarity of Transit Host Stars - Implications on Planetary Parameters

Straight-forward derivation of planetary parameters can only be achieved in transiting planetary systems. However, planetary attributes such as radius and mass strongly depend on stellar host parameters. Discovering a transit host star to be multiple leads to a necessary revision of the derived stellar and planetary parameters. Based on our observations of 14 transiting exoplanet hosts, we derive parameters of the individual components of three transit host stars (WASP-2, TrES-2, and TrES-4) which we detected to be binaries. Two of these have not been known to be multiple before. Parameters of the corresponding exoplanets are revised. High-resolution "Lucky Imaging" with AstraLux at the 2.2m Calar Alto telescope provided near diffraction limited images in i' and z' passbands. These results have been combined with existing planetary data in order to recalibrate planetary attributes. Despite the faintness (delta mag ~ 4) of the discovered stellar companions to TrES-2, TrES-4, and WASP-2, light-curve deduced parameters change by up to more than 1sigma. We discuss a possible relation between binary separation and planetary properties, which - if confirmed - could hint at the influence of binarity on the planet formation process.Comment: 9 pages, 3 Figures. Accepted by A&