Magnetism of a tetrahedral cluster-chain

Magnetic properties of a completely frustrated tetrahedral chain are briefly summarized. Using exact diagonalization, and bond-operator theory results for the ground-state phase diagram, the one-triplet excitations and the Raman spectrum are given. The link to novel tellurate materials is clarified.Comment: 2 pages, 3 figure

Environmental chemicals in eggs of Eurasian Golden Plovers "Pluvialis apricaria" breeding in Lower Saxony: is reproduction endangered?

Aus dem niedersächsischen Brutgebiet Esterweger Dose wurden von 2003 bis 2006 18 Eier aus nicht oder nur teilweise geschlüpften Gelegen sowie die Lebern eines Embryos und eines Kükens des Goldregenpfeifers auf Rückstände an Umweltchemikalien untersucht. Die Organohalogene (HCB, Σ PCB, Σ HCH, Σ DDT, Σ Chlordane und Nonachlore) sowie das Schwermetall Quecksilber wurden in sehr geringen Konzentrationen nachgewiesen. Nur die Leber des Embryos wies sehr hohe Konzentrationen an DDT und Metaboliten auf. Im Vergleich zur Kontamination der Eier anderer Watvogelarten sind die Konzentrationen der Umweltchemikalien in Goldregenpfeifereiern der Esterweger Dose als gering und den Reproduktionserfolg nicht gefährdend einzustufen.We analysed the levels of environmental chemicals in Eurasian Golden Plover samples from the breeding site Esterweger Dose, Lower Saxony, Germany. In total, 18 unhatched eggs and two livers of an embryo and a chick, respectively, were sampled from 2003 – 2006. Organochlorines (HCB, Σ PCB, Σ HCH, Σ DDT, Σ chlordane and nonachlor) and mercury were found in very low concentrations. Only in the liver of one embryo very high levels of DDT and metabolites were found. Compared with chemical levels in eggs of other wader species those in Eurasian Golden Plover eggs from the Esterweger Dose are assessed to be low and not critical for the reproductive success

A novel vacuum ultra violet lamp for metastable rare gas experiments

We report on a new design of a vacuum ultra violet (VUV) lamp for direct optical excitation of high laying atomic states e.g. for excitation of metastable rare gas atoms. The lamp can be directly mounted to ultra high vacuum vessels (p <= 10^(-10) mbar). It is driven by a 2.45 GHz microwave source. For optimum operation it requires powers of approximately 20 W. The VUV light is transmitted through a magnesium fluoride window, which is known to have a decreasing transmittance for VUV photons with time. In our special setup, after a run-time of the VUV lamp of 550 h the detected signal continuously decreased to 25 % of its initial value. This corresponds to a lifetime increase of two orders of magnitude compared to previous setups or commercial lamps

A novel vacuum ultra violet lamp for metastable rare gas experiments

We report on a new design of a vacuum ultra violet (VUV) lamp for direct optical excitation of high laying atomic states e.g. for excitation of metastable rare gas atoms. The lamp can be directly mounted to ultra high vacuum vessels (p <= 10^(-10) mbar). It is driven by a 2.45 GHz microwave source. For optimum operation it requires powers of approximately 20 W. The VUV light is transmitted through a magnesium fluoride window, which is known to have a decreasing transmittance for VUV photons with time. In our special setup, after a run-time of the VUV lamp of 550 h the detected signal continuously decreased to 25 % of its initial value. This corresponds to a lifetime increase of two orders of magnitude compared to previous setups or commercial lamps

New resonance parameters for the stable tungsten isotopes from thermal to 1 keV

Neutron resonance parameters of the 182,183,184,186W isotopes were obtained by a resonance shape analysis of experimental data measured at the time-of-flight facility GELINA using the REFIT code. In this document the analysis procedures of capture and transmission data are described. The deduced resonance parameters have been adopted in the new release of the Joint Evaluated Fusion and Fission file, i.e. JEFF-3.2, maintained by the Nuclear Energy Agency of the OECD.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard