VLA observations of Jupiter at 1.3 - 20 cm wavelengths

In order to study the vertical distribution of ammonia as a function of Jovian latitude, high resolution images were obtained with the VLA at 1.3, 2, 6 and 20 cm wavelengths. Although the interpretation of the data is quite complicated due to Jupiter's synchrotron radiation, which in fact is the dominant source of radiation at 29 cm, the belt-zone structure is clearly present at 2 and 6 cm wavelengths. At 1.3 cm near the center of the ammonia band, the structure is less pronounced, and at 20 cm it is absent. The data is currently being fitted with model atmosphere calculations. Since one probes in and through the visible cloud layers at these wavelengths (temperatures of 135 to 400 K), and the opacity is likely all provided by ammonia gas, a detailed vertical distribution of this gas can be obtained as a function of Jovian latitude. This ought to give insight in the formation processes of the white cloud layers in the zones and their absence above the belts

Bio-Blumen in kleinen Strukturen

Im ökologischen Zierpflanzenbau besteht Informationsbedarf. Viele Betriebe kombinieren aus Unsicherheit heraus den Zierpflanzenbau mit dem Anbau von Obst und Gemüse. Dies ergab eine Umfrage, die die Uni Hannover bei ökologisch geführten Zierpflanzenbetrieben durchgeführt hatte. (zitiert aus: Zander, K und Panschow, I (2001) Bio-Blumen in kleinen Strukturen, bioland 5/2001, 22

EC Visa Facilitation and Readmission Agreements: Implementing a New EU Security Approach in the Neighbourhood

With the Eastern Enlargement successfully completed, the EU is searching for a proper balance between internal security and external stabilisation that is acceptable to all sides. This paper focuses on an EU foreign policy instrument that is a case in point for this struggle: EC visa facilitation and readmission agreements. By looking at the EU's strategy on visa facilitation and readmission, this paper aims to offer a first systematic analysis of the objectives, substance and political implications of these agreements as a means to implement a new EU security approach in the neighbourhood. In offering more relaxed travel conditions in exchange for the signing of an EC readmission agreement and reforming domestic justice and home affairs, the EU has found a new way to press for reforms in neighbouring countries while addressing a major source of discontent in these countries. The analysis concludes with the broader implications of these agreements and argues that even if the facilitated travel opportunities are beneficial for the citizens of the target countries, the positive achievements are undermined by the Schengen enlargement, which makes the new member states tie up their borders to those of their neighbours.EU, EC visa facilitation, readmission agreements, European Neighbourhood Policy, Stabilisation and Association Process, Justice and Home Affairs

Recursive Method for the Density of States in One Dimension

We derive a powerful yet simple method for analyzing the local density of states in gapless one dimensional fermionic systems, including extensions such as momentum dependent interaction parameters and hard-wall boundaries. We study the crossover of the local DOS from individual density waves to the well-known asymptotic powerlaws and identify characteristic signs of spin charge separation in possible STM experiments. For semi-infinite systems a closed analytic expression is found in terms of hypergeometric functions.Comment: 5 pages and 3 figures. The latest version can be found at http://www.physik.uni-kl.de/eggert/papers/index.htm

The dynamic structure factor in impurity-doped spin chains

The effects of impurities in spin-1/2 Heisenberg chains are recently experiencing a renewed interest due to experimental realizations in solid state systems and ultra-cold gases. The impurities effectively cut the chains into finite segments with a discrete spectrum and characteristic correlations, which have a distinct effect on the dynamic structure factor. Using bosonization and the numerical Density Matrix Renormalization Group we provide detailed quantitative predictions for the momentum and energy resolved structure factor in doped systems. Due to the impurities, spectral weight is shifted away from the antiferromagnetic wave-vector $k=\pi$ into regions which normally have no spectral weight in the thermodynamic limit. The effect can be quantitatively described in terms of scaling functions, which are derived from a recurrence relation based on bosonization.Comment: submitted version, 12 pages, 2 figures, latest version and more information can be found at https://www.physik.uni-kl.de/eggert/papers/index.htm

Temporal behavior of the SO 1.707 micron ro-vibronic emission band in Io's atmosphere

We report observations of the ro-vibronic transition of SO at 1.707 microns on Io. These data were taken while Io was eclipsed by Jupiter, on four nights between July 2000 and March 2003. We analyze these results in conjunction with a previously published night to investigate the temporal behavior of these emissions. The observations were all conducted using the near-infrared spectrometer NIRSPEC on the W.M. Keck II telescope. The integrated emitted intensity for this band varies from 0.8 x 10^27 to 2.4 x 10^27 photons/sec, with a possible link to variations in Loki's infrared brightness. The band-shapes imply rotational temperatures of 550-1000K for the emitting gas, lending further evidence to a volcanic origin for sulfur monoxide. An attempt to detect the ro-vibronic transition of SO at 0.97 microns was unsuccessful; simultaneous detection with the 1.707 micron band would permit determination of the SO column abundance.Comment: 10 pages 4 figures. Accepted by Icarus 02/27/200