On some Bamberg wide-field plate catalogues recently incorporated into WFPDB

The Dr. Remeis-Sternwarte (Bamberg Observatory) hosts about 40000 astronomical photographic plates taken from the early 20th century to mid of the 1970th. In an ongoing long-term project the Bamberg wide-field plate catalogues are being incorporated into the Wide-Field Plate Database (WFPDB). Here, we describe the recent integration of seven Bamberg catalogues in the framework of a project to digitize and preserve the plates funded by the German Science Foundation. These catalogues include information about 8400 plates obtained in the period 1931 – 1963 with three Tessar cameras (WFPDB identifiers BAM003A, BAM003B and BAM009A), a Xenon camera (BAM006), a Vierlinser camera (BAM008), an Erno- star camera (BAM009B), and a Dogmar camera (BAM011). The plate observations aimed at investigations of variable stars in the Northern sky. Some of the cameras were first mounted on an astrograph in Bamberg in preparation and testing of the Bamberg large-scale project for variable star research in the Southern sky in the period 1963 – 1976. Currently information on 31 Bamberg plate archives containing 34200 plates from the Bamberg Northern- and Southern Sky Survey can be found in the WFPDB

A DIRECT MEASURING METHOD FOR THE DETERMINATION OF THE EDGING ANGLE AND THE GROUND REACTION FORCE IN ALPINE SKIING

The purpose of this study was to clarify the advantages and disadvantages of a combined dynamic and body mounted kinematical measurement system in alpine skiing. A high profile former world cup athlete of the German national team performed a test-run equipped with a bilateral insole and an inertial measurement system. In particular the edging angle and the ground reaction force were of interest. The measured values were comparable to previous findings. The main benefit can be seen in the application in the training process for an enhanced objectified technique training. The weight and the mechanical characteristics of the measuring system may slightly affect an athlete adversely

Hot subdwarf binaries - Masses and nature of their heavy compact companions

Neutron stars and stellar-mass black holes are the remnants of massive stars, which ended their lives in supernova explosions. These exotic objects can only be studied in relatively rare cases. If they are interacting with close companions they become bright X-ray sources. If they are neutron stars, they may be detected as pulsars. Only a few hundred such systems are presently known in the Galaxy. However, there should be many more binaries with basically invisible compact objects in non-interacting binaries. Here we report the discovery of unseen compact companions to hot subdwarfs in close binary systems. Hot subdwarfs are evolved helium-core-burning stars that have lost most of their hydrogen envelopes, often due to binary interactions. Using high-resolution spectra and assuming tidal synchronisation of the subdwarfs, we were able to constrain the companion masses of 32 binaries. While most hot subdwarf binaries have white-dwarf or late-type main sequence companions, as predicted by binary evolution models, at least 5% of the observed subdwarfs must have very massive companions: unusually heavy white dwarfs, neutron stars and, in some cases, even black holes. We present evolutionary models which show that such binaries can indeed form if the system has evolved through two common-envelope phases. This new connection between hot subdwarfs, which are numerous in the Galaxy, and massive compact objects may lead to a tremendous increase in the number of known neutron stars and black holes and shed some light on this dark population and its evolutionary link to the X-ray binary population.Comment: 8 pages, 5 figures, to appear in the Journal of Physics Conference Proceedings (JPCS) for the 16th European White Dwarf Workshop, Barcelona, Spain, June 30 - July 11, 200

Hot subdwarf binaries – Masses and nature of their heavy compact companions

Neutron stars and stellar-mass black holes are the remnants of massive stars, which ended their lives in supernova explosions. These exotic objects can only be studied in relatively rare cases. If they are interacting with close companions they become bright X-ray sources. If they are neutron stars, they may be detected as pulsars. Only a few hundred such systems are presently known in the Galaxy. However, there should be many more binaries with basically invisible compact objects in non-interacting binaries. Here we report the discovery of unseen compact companions to hot subdwarfs in close binary systems. Hot subdwarfs are evolved helium-core-burning stars that have lost most of their hydrogen envelopes, often due to binary interactions. Using high-resolution spectra and assuming tidal synchronisation of the subdwarfs, we were able to constrain the companion masses of 31 binaries. While most hot subdwarf binaries have white-dwarf or late-type main sequence companions, as predicted by binary evolution models, at least 5% of the observed subdwarfs must have very massive companions: unusually heavy white dwarfs, neutron stars and, in some cases, even black holes. We present evolutionary models which show that such binaries can indeed form if the system has evolved through two common-envelope phases. This new connection between hot subdwarfs, which are numerous in the Galaxy, and massive compact objects may lead to a tremendous increase in the number of known neutron stars and black holes and shed some light on this dark population and its evolutionary link to the X-ray binary population

Roquin Paralogs 1 and 2 Redundantly Repress the Icos and Ox40 Costimulator mRNAs and Control Follicular Helper T Cell Differentiation

SummaryThe Roquin-1 protein binds to messenger RNAs (mRNAs) and regulates gene expression posttranscriptionally. A single point mutation in Roquin-1, but not gene ablation, increases follicular helper T (Tfh) cell numbers and causes lupus-like autoimmune disease in mice. In T cells, we did not identify a unique role for the much lower expressed paralog Roquin-2. However, combined ablation of both genes induced accumulation of T cells with an effector and follicular helper phenotype. We showed that Roquin-1 and Roquin-2 proteins redundantly repressed the mRNA of inducible costimulator (Icos) and identified the Ox40 costimulatory receptor as another shared mRNA target. Combined acute deletion increased Ox40 signaling, as well as Irf4 expression, and imposed Tfh differentiation on CD4+ T cells. These data imply that both proteins maintain tolerance by preventing inappropriate T cell activation and Tfh cell differentiation, and that Roquin-2 compensates in the absence of Roquin-1, but not in the presence of its mutated form

Struktur von [CPRu(C0)2]2 (Cp = η5-pentamethylcyclopentadienyl)

The molecular structure of di-μ-carbonyl-bis[carbonyl(η5-pentamethylcyclopentadienyl)ruthenium] (Ru---Ru) has been determined by a single-crystal X-ray diffraction study (monoclinic, space group P21/n,a = 979.90(9), b = 831.91(7), c = 1427.75(12) pm, β = 100.026(9)°, R = 0.018). In the solid state the complex exists solely as the trans-carbonyl bridged isomer. The Ru---Ru bond length is 275.2(1) pm

Ferrocenliganden in der lanthanid-chemie: Chelatstabilisierung des ersten diorganyllanthanid(III)-halogenids

Dark red crystalline [(FcN)2Yb(μ-Cl)2 Li(THF)2] (2) has been prepared by treatment of anhydrous YbCl3 with 2-(dimethylaminom