Optische Erscheinungen und andere ungewöhnliche Wetterphänomene auf der Wetterwarte Fichtelberg

Der Fichtelberg im Erzgebirge ist mit 1215 Metern die höchste Erhebung Sachsens und liegt an der Grenze zu Tschechien. Gemeinsam mit dem nahe gelegenen Keilberg (heute tschechisch Klínovec; 1244 m) auf böhmischer Seite bildet er den höchsten Punkt des Erzgebirgskamms. Die von Südwest nach Nordost ansteigende Pultscholle des Gebirges fällt nach Süden hin steil ins Egertal (heute tschechisch Údolí Ohře) ab. In diesem, nach Süden vom Duppauer Gebirge (heute tschechisch Doupovské hory) und dem Kaiserwald (heute tschechisch Slavkovský les) eingerahmten Tal sammelt sich bei herbstlichen und winterlichen Hochdruckwetterlagen die Kaltluft (Böhmischer Nebel). Durch diese Konstellation liegt der Fichtelberg entweder in einer trockenen warmen Luftmasse darüber (Inversion) oder er wird direkt vom Böhmischen Nebel beeinflusst, wenn dieser über den Kamm fließt. Das führt zu zahlreichen optischen Erscheinungen, die es sonst in dieser Fülle nur selten gibt. So besticht der Gipfel bei Inversionswetterlagen nicht nur mit einer außergewöhnlichen Fernsicht,Der Fichtelberg im Erzgebirge ist mit 1215 Metern die höchste Erhebung Sachsens und liegt an der Grenze zu Tschechien. Gemeinsam mit dem nahe gelegenen Keilberg (heute tschechisch Klínovec; 1244 m) auf böhmischer Seite bildet er den höchsten Punkt des Erzgebirgskamms. Die von Südwest nach Nordost ansteigende Pultscholle des Gebirges fällt nach Süden hin steil ins Egertal (heute tschechisch Údolí Ohře) ab. In diesem, nach Süden vom Duppauer Gebirge (heute tschechisch Doupovské hory) und dem Kaiserwald (heute tschechisch Slavkovský les) eingerahmten Tal sammelt sich bei herbstlichen und winterlichen Hochdruckwetterlagen die Kaltluft (Böhmischer Nebel). Durch diese Konstellation liegt der Fichtelberg entweder in einer trockenen warmen Luftmasse darüber (Inversion) oder er wird direkt vom Böhmischen Nebel beeinflusst, wenn dieser über den Kamm fließt. Das führt zu zahlreichen optischen Erscheinungen, die es sonst in dieser Fülle nur selten gibt. So besticht der Gipfel bei Inversionswetterlagen nicht nur mit einer außergewöhnlichen Fernsicht, sondern auch mit ungewöhnlich starken Refraktionseffekten wie Luftspiegelungen, stark deformierter oder geteilter Sonnenscheibe sowie mehrfachen Grünen, Blauen und Roten Strahlen an der horizontnahen Sonne. Die Dämmerungsfarben sind bei derartigen Wetterlagen sehr intensiv und neben Purpur- und Gegenpurpurlicht und stark ausgeprägtem Erdschattenbogen zeichnen sich manchmal auch die Schatten weit entfernter Berge oder Wolken am Himmel ab (Crepuscularstrahlen). Fließt der Böhmische Nebel über den Erzgebirgskamm, entstehen bei gleichzeitigem Sonnenschein im Sommer Glorie und Nebelbogen und im Winter atemberaubende Eisnebelhalos. sondern auch mit ungewöhnlich starken Refraktionseffekten wie Luftspiegelungen, stark deformierter oder geteilter Sonnenscheibe sowie mehrfachen Grünen, Blauen und Roten Strahlen an der horizontnahen Sonne. Die Dämmerungsfarben sind bei derartigen Wetterlagen sehr intensiv und neben Purpur- und Gegenpurpurlicht und stark ausgeprägtem Erdschattenbogen zeichnen sich manchmal auch die Schatten weit entfernter Berge oder Wolken am Himmel ab (Crepuscularstrahlen). Fließt der Böhmische Nebel über den Erzgebirgskamm, entstehen bei gleichzeitigem Sonnenschein im Sommer Glorie und Nebelbogen und im Winter atemberaubende Eisnebelhalos

Ecosystem Development in the Constructed Catchment “Chicken Creek”

Landscapes and ecosystems are complex systems with many feedback mechanisms acting between the various abiotic and biotic components. The knowledge about these interacting processes is mainly derived from mature ecosystems. The initial development of ecosystem complexity may involve state transitions following catastrophic shifts, disturbances, or transgression of thresholds. We propose a conceptual framework of feedback processes in early states of ecosystem development affected by spatiotemporal environmental drivers. To test this concept, we used 10-year time series of hydrological, biological, geomorphological, and soil data from the constructed catchment Chicken Creek.” The 6ha site was left to unrestricted development since 2005 and was intensively monitored. The data showed a very rapid development of the site with an increasing complexity and heterogeneity. In the first years, stochastic signals like the initial substrate conditions and external drivers like extreme weather events were the most important factors resulting in abiotic/abiotic feedback mechanisms shaping the morphology of the site and creating site diversity. Initial abiotic feedback mechanisms between water and substrate were soon followed by abiotic/biotic feedbacks between biological soil crusts, invading vegetation, geomorphology, and hydrology resulting in state transitions of catchment functioning

Identification, by Homozygosity Mapping, of a Novel Locus for Autosomal Recessive Congenital Ichthyosis on Chromosome 17p, and Evidence for Further Genetic Heterogeneity

Autosomal recessive congenital ichthyosis (ARCI) comprises a group of severe disorders of keratinization, characterized by variable erythema and skin scaling. It is known for its high degree of genetic and clinical heterogeneity. Mutations in the gene for keratinocyte transglutaminase (TGM1) on chromosome 14q11 were shown in patients with ARCI, and a second locus was described, on chromosome 2q, in families from northern Africa. Three other loci for ARCI, on chromosomes 3p and 19p, were identified recently. We have embarked on a whole-genome scan for further loci for ARCI in four families from Germany, Turkey, and the United Arab Emirates. A novel ARCI locus was identified on chromosome 17p, between the markers at D17S938 and D17S1856, with a maximum LOD score of 3.38, at maximum recombination fraction 0.00, at D17S945, under heterogeneity. This locus is linked to the disease in the Turkish family and in the German family. Extensive genealogical studies revealed that the parents of the German patients with ARCI were eighth cousins. By homozygosity mapping, the localization of the gene could then be refined to the 8.4-cM interval between D17S938 and D17S1879. It could be shown, however, that ARCI in the two Arab families is linked neither to the new locus on chromosome 17p nor to one of the five loci known previously. Our findings give evidence of further genetic heterogeneity that is not linked to distinctive phenotypes

Integrins Form an Expanding Diffusional Barrier that Coordinates Phagocytosis

Phagocytosis is initiated by lateral clustering of receptors, which in turn activates Src-family kinases (SFKs). Activation of SFKs requires depletion of tyrosine phosphatases from the area of particle engagement. We investigated how the major phosphatase CD45 is excluded from contact sites, using single-molecule tracking. The mobility of CD45 increased markedly upon engagement of Fcγ receptors. While individual CD45 molecules moved randomly, they were displaced from the advancing phagocytic cup by an expanding diffusional barrier. By micropatterning IgG, the ligand of Fcγ receptors, we found that the barrier extended well beyond the perimeter of the receptor-ligand engagement zone. Second messengers generated by Fcγ receptors activated integrins, which formed an actin-tethered diffusion barrier that excluded CD45. The expanding integrin wave facilitates the “zippering” of Fcγ receptors onto the target and integrates the information from sparse receptor-ligand complexes, coordinating the progression and ultimate closure of the phagocytic cup

High contrast imaging at the LBT: the LEECH exoplanet imaging survey

In Spring 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began its $\sim$130-night campaign from the Large Binocular Telescope (LBT) atop Mt Graham, Arizona. This survey benefits from the many technological achievements of the LBT, including two 8.4-meter mirrors on a single fixed mount, dual adaptive secondary mirrors for high Strehl performance, and a cold beam combiner to dramatically reduce the telescope's overall background emissivity. LEECH neatly complements other high-contrast planet imaging efforts by observing stars at L' (3.8 $\mu$m), as opposed to the shorter wavelength near-infrared bands (1-2.4 $\mu$m) of other surveys. This portion of the spectrum offers deep mass sensitivity, especially around nearby adolescent ($\sim$0.1-1 Gyr) stars. LEECH's contrast is competitive with other extreme adaptive optics systems, while providing an alternative survey strategy. Additionally, LEECH is characterizing known exoplanetary systems with observations from 3-5$\mu$m in preparation for JWST.Comment: 12 pages, 5 figures. Proceedings of the SPIE, 9148-2

The LEECH Exoplanet Imaging Survey: Limits on Planet Occurrence Rates Under Conservative Assumptions

We present the results of the largest $L^{\prime}$ ($3.8~\mu$m) direct imaging survey for exoplanets to date, the Large Binocular Telescope Interferometer (LBTI) Exozodi Exoplanet Common Hunt (LEECH). We observed 98 stars with spectral types from B to M. Cool planets emit a larger share of their flux in $L^{\prime}$ compared to shorter wavelengths, affording LEECH an advantage in detecting low-mass, old, and cold-start giant planets. We emphasize proximity over youth in our target selection, probing physical separations smaller than other direct imaging surveys. For FGK stars, LEECH outperforms many previous studies, placing tighter constraints on the hot-start planet occurrence frequency interior to $\sim20$ au. For less luminous, cold-start planets, LEECH provides the best constraints on giant-planet frequency interior to $\sim20$ au around FGK stars. Direct imaging survey results depend sensitively on both the choice of evolutionary model (e.g., hot- or cold-start) and assumptions (explicit or implicit) about the shape of the underlying planet distribution, in particular its radial extent. Artificially low limits on the planet occurrence frequency can be derived when the shape of the planet distribution is assumed to extend to very large separations, well beyond typical protoplanetary dust-disk radii ($\lesssim50$ au), and when hot-start models are used exclusively. We place a conservative upper limit on the planet occurrence frequency using cold-start models and planetary population distributions that do not extend beyond typical protoplanetary dust-disk radii. We find that $\lesssim90\%$ of FGK systems can host a 7 to 10 $M_{\mathrm{Jup}}$ planet from 5 to 50 au. This limit leaves open the possibility that planets in this range are common.Comment: 31 pages, 13 figures, accepted to A

Views on the Past, Present, and Future of Business and Information Systems Engineering

‘‘The times they are a-changin,’’ a famous song title by Bob Dylan, also applies to our profession and our subject of study. Information technology has always been a driver for innovation. The recent years, however, have seen IT-based innovations that truly impact everybody’s lives. Everything that can be digitized will be digitized, and this trend is continuing at an amazing speed. For a discipline that looks at the design and utilization of information systems these are exciting times. Yet, it is also a time full of challenges. While our discipline has much to contribute, it competes with other disciplines for topics and ideas. Also, the scope of topics studied has become broader and broader, and so have our methods. While initial work in Business and Information Systems Engineering (BISE) was often rooted in artificial intelligence, database systems, or operations research, the community has adopted new approaches to address new types of problems. Nowadays, we also have a strong group of academics working primarily with empirical methods or methods from microeconomics, to name just a few. This development towards a more multiparadigmatic discipline also had its challenges and there were controversial discussions along the way

Efficacy and toxicity of bimodal radiotherapy in WHO grade 2 meningiomas following subtotal resection with carbon ion boost:Prospective phase 2 MARCIE trial

Background: Novel radiotherapeutic modalities using carbon ions provide an increased relative biological effectiveness (RBE) compared to photons, delivering a higher biological dose while reducing radiation exposure for adjacent organs. This prospective phase 2 trial investigated bimodal radiotherapy using photons with carbon-ion (C12)-boost in patients with WHO grade 2 meningiomas following subtotal resection (Simpson grade 4 or 5).Methods:A total of 33 patients were enrolled from July 2012 until July 2020. The study treatment comprised a C12-boost (18 Gy [RBE] in 6 fractions) applied to the macroscopic tumor in combination with photon radiotherapy (50 Gy in 25 fractions). The primary endpoint was the 3-year progression-free survival (PFS), and the secondary endpoints included overall survival, safety and treatment toxicities. Results:With a median follow-up of 42 months, the 3-year estimates of PFS, local PFS and overall survival were 80.3%, 86.7%, and 89.8%, respectively. Radiation-induced contrast enhancement (RICE) was encountered in 45%, particularly in patients with periventricularly located meningiomas. Patients exhibiting RICE were mostly either asymptomatic (40%) or presented immediate neurological and radiological improvement (47%) after the administration of corticosteroids or bevacizumab in case of radiation necrosis (3/33). Treatment-associated complications occurred in 1 patient with radiation necrosis who died due to postoperative complications after resection of radiation necrosis. The study was prematurely terminated after recruiting 33 of the planned 40 patients. Conclusions:Our study demonstrates a bimodal approach utilizing photons with C12-boost may achieve a superior local PFS to conventional photon RT, but must be balanced against the potential risks of toxicities.</p