Breitbandversorgung, Medienkonvergenz, Leitmedien. Strukturwandel der Massenmedien und Herausforderungen für die Medienpolitik

Die Tageszeitung auf einem E-Book-Reader lesen, mit dem Smartphone fernsehen, über das Internet Radio hören und am Fernseher im Internet surfen - die etablierten Medien scheinen zunehmend ihre Kontur zu verlieren. Der Strukturwandel mündet in Medienkonvergenz, und damit ist auch die Frage angesprochen, ob traditionelle Leitmedien ihren Stellenwert einbüßen, selbst wenn Presse, Hörfunk und Fernsehen offenbar wichtige Knotenpunkte der medial vernetzten Gesellschaft bleiben. Diese Entwicklungen werfen neue medienpolitische Fragen auf und stellen den Gesetzgeber vor die Herausforderung, mit konvergenten Medienangeboten Schritt zu halten und die Regulierung anzupassen. Ziel der Medien- und Netzpolitik ist es dabei, Barrieren für Medieninnovationen abzubauen und zugleich die normativen Aspekte einer demokratischen Medienpolitik nicht aus den Augen zu verlieren. Dieses Buch greift zentrale Fragestellungen des langfristigen Medienwandels auf und benennt Handlungsoptionen. Als wichtige Pokitikfelder identifizieren die Autoren den Ausbau der Breitbandnetze, die Netz- und Plattformneutralität, die Gewährleistung von Anbieter- und Meinungsvielfalt sowie die Transparenz im Internet. Die Publikation basiert auf TAB-Arbeitsbericht Nr. 149 »Gesetzliche Regelungen für den Zugang zur Informationsgesellschaft«

Isotope shift in the dielectronic recombination of three-electron ^{A}Nd^{57+}

Isotope shifts in dielectronic recombination spectra were studied for Li-like ^{A}Nd^{57+} ions with A=142 and A=150. From the displacement of resonance positions energy shifts \delta E^{142,150}(2s-2p_1/2)= 40.2(3)(6) meV (stat)(sys)) and \delta E^{142,150}(2s-2p_3/2) = 42.3(12)(20) meV of 2s-2p_j transitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of ^{142,150}\delta = -1.36(1)(3) fm^2. The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size.Comment: 10 pages, 3 figures, accepted for publication in Physical Review Letter

Parsec-scale dust distributions in Seyfert galaxies - Results of the MIDI AGN snapshot survey

The emission of warm dust dominates the mid-infrared spectra of active galactic nuclei (AGN). Only interferometric observations provide the necessary angular resolution to resolve the nuclear dust and to study its distribution and properties. The investigation of dust in AGN cores is hence one of the main science goals for the MID-infrared Interferometric instrument MIDI at the VLTI. As the first step, the feasibility of AGN observations was verified and the most promising sources for detailed studies were identified. This was carried out in a "snapshot survey" with MIDI using Guaranteed Time Observations. In the survey, observations were attempted for 13 of the brightest AGN in the mid-infrared which are visible from Paranal. The results of the three brightest, best studied sources have been published in separate papers. Here we present the interferometric observations for the remaining 10, fainter AGN. For 8 of these, interferometric measurements could be carried out. Size estimates or limits on the spatial extent of the AGN-heated dust were derived from the interferometric data of 7 AGN. These indicate that the dust distributions are compact, with sizes on the order of a few parsec. The derived sizes roughly scale with the square root of the luminosity in the mid-infrared, s ~ sqrt(L), with no clear distinction between type 1 and type 2 objects. This is in agreement with a model of nearly optically thick dust structures heated to T ~ 300 K. For three sources, the 10 micron feature due to silicates is tentatively detected either in emission or in absorption. Based on the results for all AGN studied with MIDI so far, we conclude that in the mid-infrared the differences between individual galactic nuclei are greater than the generic differences between type 1 and type 2 objects.Comment: 18 pages, 8 figures, updated to version published in A&A 502, 67-8

Milli-arcsecond astrophysics with VSI, the VLTI spectro-imager in the ELT era

Nowadays, compact sources like surfaces of nearby stars, circumstellar environments of stars from early stages to the most evolved ones and surroundings of active galactic nuclei can be investigated at milli-arcsecond scales only with the VLT in its interferometric mode. We propose a spectro-imager, named VSI (VLTI spectro-imager), which is capable to probe these sources both over spatial and spectral scales in the near-infrared domain. This instrument will provide information complementary to what is obtained at the same time with ALMA at different wavelengths and the extreme large telescopes.Comment: 8 pages. To be published in the proceedings of the ESO workshop "Science with the VLT in the ELT Era", held in Garching (Germany) on 8-12 October 2007, A. Moorwood edito

VSI: the VLTI spectro-imager

The VLTI Spectro Imager (VSI) was proposed as a second-generation instrument of the Very Large Telescope Interferometer providing the ESO community with spectrally-resolved, near-infrared images at angular resolutions down to 1.1 milliarcsecond and spectral resolutions up to R=12000. Targets as faint as K=13 will be imaged without requiring a brighter nearby reference object. The unique combination of high-dynamic-range imaging at high angular resolution and high spectral resolution enables a scientific program which serves a broad user community and at the same time provides the opportunity for breakthroughs in many areas of astrophysic including: probing the initial conditions for planet formation in the AU-scale environments of young stars; imaging convective cells and other phenomena on the surfaces of stars; mapping the chemical and physical environments of evolved stars, stellar remnants, and stellar winds; and disentangling the central regions of active galactic nuclei and supermassive black holes. VSI will provide these new capabilities using technologies which have been extensively tested in the past and VSI requires little in terms of new infrastructure on the VLTI. At the same time, VSI will be able to make maximum use of new infrastructure as it becomes available; for example, by combining 4, 6 and eventually 8 telescopes, enabling rapid imaging through the measurement of up to 28 visibilities in every wavelength channel within a few minutes. The current studies are focused on a 4-telescope version with an upgrade to a 6-telescope one. The instrument contains its own fringe tracker and tip-tilt control in order to reduce the constraints on the VLTI infrastructure and maximize the scientific return.Comment: 12 pages, to be published in Proc. SPIE conference 7013 "Optical and Infrared Interferometry", Schoeller, Danchi, and Delplancke, F. (eds.). See also http://vsi.obs.ujf-grenoble.f

The Emergence of New Islamic Economic and Business Moralities

This article aims to explore the sources of the observed transformation in the embeddedness of economic, business, and financial practices of Muslim individuals in comparison to premodern period Muslims. It argues that the predomination of instrumental reasoning in modern times, as opposed to substantive morality in everyday practice, is one of the main reasons behind the transformation of embeddedness of Muslim individuals. Instrumental reasoning, being the dominant methodology, leads to diminished submergence in social relations; that is not limited to interpersonal relationships, but further extended to the core religious acts. How such an emergent economic and business morality is reconciled with the Islamic substantive morality is examined. It is argued that “transformation of exception into norm” is the main method used to reconcile instrumental reasoning with Islamic law in fulfilling religious obligations, at least in terms of fulfilling the form and in complying with the necessities of modern life. This has led to the emergence of new economic and business moralities