Ks- and Lp-band polarimetry on stellar and bow-shock sources in the Galactic center

Infrared observations of the Galactic center (GC) provide a unique opportunity to study stellar and bow-shock polarization effects in a dusty environment. The goals of this work are to present new Ks- and Lp-band polarimetry on an unprecedented number of sources in the central parsec of the GC, thereby expanding our previous results in the H- and Ks-bands. We use AO-assisted Ks- and Lp-band observations, obtained at the ESO VLT. High precision photometry and the new polarimetric calibration method for NACO allow us to map the polarization in a region of 8" x 25" (Ks) resp. 26" x 28" (Lp). These are the first polarimetric observations of the GC in the Lp-band in 30 years, with vastly improved spatial resolution compared to previous results. This allows resolved polarimetry on bright bow-shock sources in this area for the first time at this wavelength. We find foreground polarization to be largely parallel to the Galactic plane (Ks-band: 6.1% at 20 degrees, Lp-band: 4.5% at 20 degrees, in good agreement with our previous findings and with older results. The previously described Lp-band excess in the foregound polarization towards the GC could be confirmed here for a much larger number of sources. The bow-shock sources contained in the FOV seem to show a different relation between the polarization in the observed wavelength bands than what was determined for the foreground. This points to the different relevant polarization mechanisms. The resolved polarization patterns of IRS 5 and 10W match the findings we presented earlier for IRS~1W. Additionally, intrinsic Lp-band polarization was measured for IRS 1W and 21, as well as for other, less prominent MIR-excess sources (IRS 2S, 2L, 5NE). The new data offer support for the presumed bow-shock nature of several of these sources (1W, 5, 5NE, 10W, 21) and for the model of bow-shock polarization presented in our last work.Comment: 19 pages, 18 figure

Noise thermometry in narrow 2D electron gas heat baths connected to a quasi-1D interferometer

Thermal voltage noise measurements are performed in order to determine the electron temperature in nanopatterned channels of a GaAs/AlGaAs heterostructure at bath temperatures of 4.2 and 1.4 K. Two narrow two-dimensional (2D) heating channels, close to the transition to the one-dimensional (1D) regime, are connected by a quasi-1D quantum interferometer. Under dc current heating of the electrons in one heating channel, we perform cross-correlated noise measurements locally in the directly heated channel and nonlocally in the other channel, which is indirectly heated by hot electron diffusion across the quasi-1D connection. We observe the same functional dependence of the thermal noise on the heating current. The temperature dependence of the electron energy-loss rate is reduced compared to wider 2D systems. In the quantum interferometer, we show the decoherence due to the diffusion of hot electrons from the heating channel into the quasi-1D system, which causes a thermal gradient.Comment: 6 pages, 5 figure

Integrierte Konzernsteuerung in der Kommunalverwaltung

In den vergangenen Jahren haben viele Kommunen ihre Aufgaben aus der Kernverwaltung in verselbstständigte Aufgabenträger ausgegliedert. Dieser Trend ist trotz einzelner Rekommunalisierungen ungebrochen. Es entsteht ein konzernähnliches Gebilde. Obwohl die Kommune, insbesondere Verwaltungsführung und Politik, für die Aufgabenerfüllung auch in den ausgegliederten Einheiten verantwortlich ist, werden die verselbstständigten Aufgabenträger oftmals nicht ausreichend in die Steuerung der Kommune einbezogen. Es fehlt an einer integrierten Konzernsteuerung. Ausgehend von der Begriffsklärung und Darstellung der spezifischen Merkmale des kommunalen Konzerns werden die Problemlagen der kommunalen Konzernsteuerung beschrieben und Anforderungen an eine integrierte Konzernsteuerung in der Kommune aufgezeigt.In recent years, many municipalities have set up independent companies to perform their tasks. This trend has continued unabated despite some remunicipalisation of tasks. The result is a local group consisting of the municipal authority and the independent companies. Although the municipality, in particular local management and local council remain responsible for the completion of tasks, the independent carriers are often not sufficiently involved in the control of the municipality. There is a lack of integrated corporate management. Based on the definition and presentation of the specific characteristics of the local group, the problems of local group management are described and requirements for integrated local group management in the municipality are identified

The demand for global and local environmental protection - experimental evidence from climate change mitigation in Beijing

In this study, the real demand for global and local environmental protection in Beijing, China, is elicited and investigated. Participants from Beijing were offered the opportunity to contribute to voluntary climate change mitigation by purchasing permits from two Chinese CO2 emissions trading schemes (ETS). Purchased permits were withdrawn from the ETS. Since CO2 emissions mitigation is inevitably linked to other local benefits like the reduction in emissions of air pollutants, the aim of our study is to establish the demand for local and global environmental protection. To this end, Beijing and Shenzhen ETS permits were offered. The result is that at low prices the demand for Beijing ETS permits is significantly higher than for Shenzhen ETS permits indicating that a substantial part of the revealed demand for voluntary climate change mitigation in Beijing is driven by concerns for local co-benefits of CO2 emissions reduction. Our research identifies the important role of private benefits in the voluntary provision of the global public good climate change mitigation and provides first experimental evidence for China