Revision of the Dobson total ozone series at Hohenpeissenberg

Total ozone measurements with the Dobson No. 104 (D 104) have been performed at the Meteorological Observatory Hohenpeissenberg since 1967. A critical review of this time series and the comparison with other instruments like TOMS or Brewer spectrophotometer revealed some intervals with uncertainties. Especially in the early eighties a monthly mean bias of about minus 3 percent to TOMS-data with annual variations depending on the mean sun-height exists. An extreme amplitude of 5.6 percent occurs in 1980 with minus 0.76 percent (February) and minus 6.36 percent (July). Two different methods were applied to reprocess the Dobson data set. A comparison of the differently recalculated data showed, that the application of N-corrections by means of the standard-lamp tests starting from the reference values of the Arosa Intercomparison 1986 yields better results than the N-corrections based on a Langley-pilot of the Arosa Intercomparison 1978. The extreme amplitude of the year 1980 is now reduced to 3.02 percent. There is still a slight drift in the monthly and yearly mean differences between TOMS and revised Dobson data. It cannot be excluded, that the satellite data may be responsible for the trend

UV-observations with a Brewer spectrophotometer at Hohenpeissenberg

Regular spectral UV-B measurements with a Brewer spectrophotometer have been performed at Hohenpeissenberg since 1990. Intercomparison of the Brewer instrument with other UV-B monitoring devices have shown agreement to within plus or minus 10 percent. Comparisons of UV-B spectra measured on fair weather days reveal the well known increasing influence of ozone on UV-B irradiance with decreasing wavelengths. The integral amplification factor the erythemal irradiance reaches values up to 2.8, which can be diminished by increasing turbidity. The influence of cirrus cloud on the UV-B is also shown

Transverse excitations of ultracold matter waves upon propagation past abrupt waveguide changes

The propagation of ultracold atomic gases through abruptly changing waveguide potentials is examined in the limit of non-interacting atoms. Time-independent scattering calculations of microstructured waveguides with discontinuous changes in the transverse harmonic binding potentials are used to mimic waveguide perturbations and imperfections. Three basic configurations are examined: step-like, barrier-like and well-like with waves incident in the ground mode. At low energies, the spectra rapidly depart from single-moded, with significant transmission and reflection of excited modes. The high-energy limit sees 100 percent transmission, with the distribution of the transmitted modes determined simply by the overlap of the mode wave functions and interference.Comment: 20 pages, 7 figures, under review PR

Can Euroscepticism Contribute to a European Public Sphere? The Europeanization of Media Discourses about Euroscepticism across Six Countries

This study compares the media discourses about Euroscepticism in 2014 across six countries (United Kingdom, Ireland, France, Spain, Sweden, and Denmark). We assess the extent to which the mass media's reporting of Euroscepticism indicates the Europeanization of public spheres. Using a mixed-methods approach combining LDA topic modeling and qualitative coding, we find that approximately 70 per cent of print articles mentioning "Euroscepticism" or "Eurosceptic" are framed in a non-domestic (i.e. European) context. In five of the six cases studied, articles exhibiting a European context are strikingly similar in content, with the British case as the exception. However, coverage of British Euroscepticism drives Europeanization in other Member States. Bivariate logistic regressions further reveal three macro-level structural variables that significantly correlate with a Europeanized media discourse: newspaper type (tabloid or broadsheet), presence of a strong Eurosceptic party, and relationship to the EU budget (net contributor or receiver of EU funds).Comment: 29 pages, 2 figures, 4 tables, 2 appendice

RHEED studies of Ag/Si(111) growth at low temperatures

This thesis showed that it is possible to achieve well ordered growth at low temperatures when chaing fluxes during the course of the deposition. It was also demonstrated that nucleation theory fails to predict or explain at least part of the results, in particular when deposition takes place at an initially low rate, with presumably a relatively low nucleation density, followed by a change to a high flux rate. This points to an inherent lack of nucleation theory; alternative explanations are presented based on flux-independent growth as reported by Roos (Surf. Sci. 302 (1994) 37)

Therapeutische Effizienz von Naftidrofuryl auf die periphere arterielle Verschlußkrankheit im Stadium II unter besonderer Berücksichtigung der transkutanen Sauerstoffpartialdruckmessung mittels Laufbandbelastung

Eine Option zur Verbesserung der klinischen Beschwerdesymptomatik bei Patienten mit arterieller Verschlusskrankheit im Stadium II ist die Applikation vasoaktiver Substanzen. Zur Beurteilung der medikamentösen Therapieeffizienz werden die Verbesserung der schmerzfreien und maximalen Gehstrecke herangezogen. Die transkutane Sauerstoffpartialdruckmessung (tcPO2) erlaubt im Vergleich zur schmerzfreien Gehstrecke möglicherweise eine objektivere Beurteilung der medikamentösen Therapieeffekte. 22 Patienten im Alter von 61 Jahren (im Mittel) wurden im Rahmen einer kontrollierten, prospektiv angelegten Doppelblindstudie zur Beurteilung des Therapieeffektes von Naftidrofuryl in die Untersuchung aufgenommen. 12 Patienten wurden mit Naftidrofuryl (2x300 mg/die p.o.), 10 Patienten mit einem Placebo über einen Zeitraum von 12 Wochen behandelt. Die beiden Kollektive unterschieden sich nicht signifikant im Hinblick auf Alter, Geschlecht, kardiovaskuläre Morbidität und Gefäßstatus. Bei allen Patienten wurden initial eine Dopplerultraschalluntersuchung, eine Oszillographie sowie eine transkutane Sauerstoffpartialdruckmessung durchgeführt. Zu weiteren fünf Messzeitpunkten vor / unter Therapie erfolgten Registrierungen des transkutanen Sauerstoffpartialdruckes vor / unter Belastung. In der Placebogruppe stieg die schmerzfreie Gehstrecke im Mittel von 177 auf 242 m an, in der Naftidrofuryl-Gruppe von 186 auf 257 m (Differenz 23,5 versus 38,2%; ns). Der Vergleich der transkutan gemessenen PO2-Werte vor / unter Therapie zeigte keine signifikanten Unterschiede (in Ruhe bzw. unter Belastung) zwischen beiden Kollektiven. Die engste, jedoch negative Korrelation, bestand zwischen schmerzfreier Gehstrecke und dem Fußindex (Quotient aus tcPO2 Fuß Belastung und tcPO2 Fuß Ruhe in mmHg). Unsere Untersuchungen belegen eine nur leichtgradige Verbesserung der schmerzfreien Gehstrecke sowohl unter Placebo als auch unter Naftidrofuryl-Therapie. Wir erachten die schmerzfreie Gehstrecke als subjektive Angabe zur Beurteilung einer Therapieeffizienz für nur bedingt geeignet. Die transkutan durchgeführten PO2-Messungen haben ebenfalls keine signifikanten Unterschiede zwischen Verum und Placebo zeigen können. Es bleibt zu diskutieren, ob punktuelle transkutane PO2-Messungen den Therapieverlauf zufriedenstellend widerspiegeln können. Andererseits müssen Untersuchungen an größeren Patientenkollektiven durchgeführt werden, um die, in unserer Untersuchung nicht ausreichend nachweisbaren positiven Therapieeffekte von Naftidrofuryl zu bestätigen

Analysis of flow structures and near wall behavior of fluid flow and local heat transfer in heat exchangers with inclined flat tubes

Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.Compact flat tube heat exchangers with inclined refrigerant tubes and plane fins are studied at Reynolds numbers based on the hydraulic diameter of Redh=3900 and Redh=2500. The fluid field is measured parallel to the fins and the wall distance is varied. The fluid movement and particularly the change of fluid movement close to the fin are examined. A steady two dimensional CFD simulation is developed to provide an efficient model for geometric optimization. The model is validated by experimental flow measurements. This paper also compares the local heat transfer distribu-tion on the fin with near wall PIV measurements and seeks relations between certain flow structures and enhanced heat transfer. Shadowing effects prevent the examination of instan-taneous velocity fields in the named geometries. The gappy proper orthogonal decomposition (Gappy POD) is tested for the reconstruction of instantaneous velocity data in shadowed region.vk201

Field dependence of the thermopower of CeNiSn

Previously measured thermopower data of CeNiSn exhibit a significant sample dependence and non-monotonous behavior in magnetic fields. In this paper we demonstrate that the measured thermopower S(T) may contain a contribution from the huge Nernst coefficient of the compound, even in moderate fields of 2 T. A correction for this effect allows to determine the intrinsic field dependence of S(T). The observed thermopower behavior can be understood from Zeeman splitting of a V-shaped pseudogap in magnetic fields.Comment: 4 pages, accepted for Journal of Physics: Conference Series, proceedings of LT 2

Gray and white matter astrocytes differ in basal metabolism but respond similarly to neuronal activity

Astrocytes are a heterogeneous population of glial cells in the brain, which adapt their properties to the requirements of the local environment. Two major groups of astrocytes are protoplasmic astrocytes residing in gray matter as well as fibrous astrocytes of white matter. Here, we compared the energy metabolism of astrocytes in the cortex and corpus callosum as representative gray matter and white matter regions, in acute brain slices taking advantage of genetically encoded fluorescent nanosensors for the NADH/NAD+ redox ratio and for ATP. Astrocytes of the corpus callosum presented a more reduced basal NADH/NAD+ redox ratio, and a lower cytosolic concentration of ATP compared to cortical astrocytes. In cortical astrocytes, the neurotransmitter glutamate and increased extracellular concentrations of K+, typical correlates of neuronal activity, induced a more reduced NADH/NAD+ redox ratio. While application of glutamate decreased [ATP], K+ as well as the combination of glutamate and K+ resulted in an increase of ATP levels. Strikingly, a very similar regulation of metabolism by K+ and glutamate was observed in astrocytes in the corpus callosum. Finally, strong intrinsic neuronal activity provoked by application of bicuculline and withdrawal of Mg2+ caused a shift of the NADH/NAD+ redox ratio to a more reduced state as well as a slight reduction of [ATP] in gray and white matter astrocytes. In summary, the metabolism of astrocytes in cortex and corpus callosum shows distinct basal properties, but qualitatively similar responses to neuronal activity, probably reflecting the different environment and requirements of these brain regions