Goldstone bosons in the color-flavor locked phase

We study pseudoscalar meson excitations in the color-flavor locked phase within a Nambu-Jona-Lasinio-type model by calculating diquark loops.Comment: Talk given by V.W. at the Helmholtz International Summer School "Dense Matter In Heavy Ion Collisions and Astrophysics", Dubna, August 21 - September 1, 2006; 4 pages, to appear in the proceeding

Pseudoscalar Goldstone bosons in the color-flavor locked phase at moderate densities

The properties of the pseudoscalar Goldstone bosons in the color-flavor locked phase at moderate densities are studied within a model of the Nambu--Jona-Lasinio type. The Goldstone bosons are constructed explicitly by solving the Bethe-Salpeter equation for quark-quark scattering in random phase approximation. Main focus of our investigations are (i) the weak decay constant in the chiral limit, (ii) the masses of the flavored (pseudo-) Goldstone bosons for non-zero but equal quark masses, (iii) their masses and effective chemical potentials for non-equal quark masses, and (iv) the onset of kaon condensation. We compare our results with the predictions of the low-energy effective field theory. The deviations from results obtained in the weak-coupling limit are discussed in detail.Comment: 18 pages, 12 figure

Untersuchungen zur Reaktionskinetik und Rückkontaktmorpholgie von CuInSe2-Dünnschichtsolarzellen

Aufgrund der geringeren Kontrolle des Absorberwachstums liegt der Wirkungsgrad sequentiell prozessierter CuInSe2-Dünnschichtsolarzellen deutlich unter dem maximal erreichbaren Wirkungsgrad für dieses Materialsystem. Ziel dieser Arbeit ist es daher, Möglichkeiten der Einflussnahme auf das Wachstum von CuInSe2-Absorbern für einen sequentiellen Prozess in einem offenen System zu beschreiben. Es wird dabei auf die industriell übliche Verwendung von stark toxischen H2Se verzichtet und anstelle dessen elementares Selen als Chalkogenquelle verwendet. Durch die Untersuchung der Phasenbildungsreaktionen zeigt sich, dass vor allem die Variation der Selenrate eine entscheidende Rolle bei der CuInSe2-Bildung spielt. Es können weiterhin Ansätze für die CuInSe2-Bildung bei niedrigen Temperaturen aufgezeigt werden

Bestimmung wichtiger Bindungseigenschaften des transsynaptischen Neurexin/Neuroligin-Komplexes mithilfe der Oberflächenplasmonresonanz-Technologie

Das Zentralnervensystem bildet ein komplexes Netzwerk aus Neuronen, die an den Synapsen miteinander kommunizieren. An der Synapse findet eine Interaktion zwischen den Adhäsionsproteinen Neurexin (präsynaptisch) und Neuroligin (postsynaptisch) statt. Die vorliegende Arbeit untersucht die Bindung der beiden Partner unter Verwendung der Oberflächenplasmonresonanz-Technologie, einer optischen Messmethode, die Daten über Affinität und Kinetik in Echtzeit liefert. Bei den Experimenten konzentrierte ich mich auf die Auswirkungen einer spezifischen Sequenz aus 37 Aminosäuren in β-Neurexin, einer extrazellulär kürzeren Variante dieser synaptischen Zelloberflächenmoleküle. Es zeigt sich, dass die 37 Aminosäuren eine inhibitorische Wirkung auf die Bildung des Neurexin/Neuroligin-Komplexes haben, während sie ihn nach erfolgter Bindung stabilisieren. Die Diskussion vergleicht die in dieser Arbeit ermittelten Ergebnisse mit Referenzarbeiten und stellt methodische Unterschiede heraus

Underwater Use of a Hyperspectral Camera to Estimate Optically Active Substances in theWater Column of Freshwater Lakes

Freshwater lakes provide many important ecosystem functions and services to support biodiversity and human well-being. Proximal and remote sensing methods represent an efficient approach to derive water quality indicators such as optically active substances (OAS). Measurements of above-ground remote and in situ proximal sensors, however, are limited to observations of the uppermost water layer. We tested a hyperspectral imaging system, customized for underwater applications, with the aim to assess concentrations of chlorophyll a (CHLa) and colored dissolved organic matter (CDOM) in the water columns of four freshwater lakes with different trophic conditions in Central Germany. We established a measurement protocol that allowed consistent reflectance retrievals at multiple depths within the water column independent of ambient illumination conditions. Imaging information from the camera proved beneficial for an optimized extraction of spectral information since low signal areas in the sensor’s field of view, e.g., due to non-uniform illumination, and other interfering elements, could be removed from the measured reflectance signal for each layer. Predictive hyperspectral models, based on the 470 nm–850 nm reflectance signal, yielded estimates of both water quality parameters (R² = 0.94, RMSE = 8.9 µg L−1 for CHLa; R² = 0.75, RMSE = 0.22 m−1 for CDOM) that were more accurate than commonly applied waveband indices (R² = 0.83, RMSE = 13.2 µg L−1 for CHLa; R² = 0.66, RMSE = 0.25 m−1 for CDOM). Underwater hyperspectral imaging could thus facilitate future water monitoring efforts through the acquisition of consistent spectral reflectance measurements or derived water quality parameters along the water column, which has the potential to improve the link between above-surface proximal and remote sensing observations and in situ point-based water probe measurements for ground truthing or to resolve the vertical distribution of OAS

Visionär mit Bodenhaftung. Zur Erinnerung an den Beweger Josef Homeyer

Im 30. März 2010 ist in Hildesheim Josef Homeyer gestorben. Er war von 1983 bis 2004 Bischof dieser flächengroßen Diasporadiözese. Sein Doktorgrad, erworben 1955, stammt nicht aus der Theologie, sondern aus der Philosophie, und seine Dissertation gilt der Frage nach „Entwicklung und Begriff der Soziologie“. Der Fachbereich Erziehungswissenschaft der Universität Hannover hat ihm ein Ehrendoktorat verliehen. So haben wir ihn in Erinnerung: einer, der intelligent über den Rain grasen konnte. Am Anfang sah das nicht so aus. Nach der Priesterweihe (1958) fand sich der am 1. August 1928 in Harsewinkel im Herzen des Münsterlandes Geborene bald im Dienst seiner Heimatdiözese Münster: 1961-1966 Landvolkseelsorger, 1966-1971 Schulreferent der Diözese. (...

Phylogenetic relationships in Cortinarius, section Calochroi, inferred from nuclear DNA sequences

<p>Abstract</p> <p>Background</p> <p>Section <it>Calochroi </it>is one of the most species-rich lineages in the genus <it>Cortinarius </it>(Agaricales, Basidiomycota) and is widely distributed across boreo-nemoral areas, with some extensions into meridional zones. Previous phylogenetic studies of <it>Calochroi </it>(incl. section <it>Fulvi</it>) have been geographically restricted; therefore, phylogenetic and biogeographic relationships within this lineage at a global scale have been largely unknown. In this study, we obtained DNA sequences from a nearly complete taxon sampling of known species from Europe, Central America and North America. We inferred intra- and interspecific phylogenetic relationships as well as major morphological evolutionary trends within section <it>Calochroi </it>based on 576 ITS sequences, 230 ITS + 5.8S + D1/D2 sequences, and a combined dataset of ITS + 5.8S + D1/D2 and RPB1 sequences of a representative subsampling of 58 species.</p> <p>Results</p> <p>More than 100 species were identified by integrating DNA sequences with morphological, macrochemical and ecological data. <it>Cortinarius </it>section <it>Calochroi </it>was consistently resolved with high branch support into at least seven major lineages: <it>Calochroi</it>, <it>Caroviolacei</it>, <it>Dibaphi</it>, <it>Elegantiores</it>, <it>Napi</it>, <it>Pseudoglaucopodes </it>and <it>Splendentes</it>; whereas <it>Rufoolivacei </it>and <it>Sulfurini </it>appeared polyphyletic. A close relationship between <it>Dibaphi</it>, <it>Elegantiores</it>, <it>Napi </it>and <it>Splendentes </it>was consistently supported. Combinations of specific morphological, pigmentation and molecular characters appear useful in circumscribing clades.</p> <p>Conclusion</p> <p>Our analyses demonstrate that <it>Calochroi </it>is an exclusively northern hemispheric lineage, where species follow their host trees throughout their natural ranges within and across continents. Results of this study contribute substantially to defining European species in this group and will help to either identify or to name new species occurring across the northern hemisphere. Major groupings are in partial agreement with earlier morphology-based and molecular phylogenetic hypotheses, but some relationships were unexpected, based on external morphology. In such cases, their true affinities appear to have been obscured by the repeated appearance of similar features among distantly related species. Therefore, further taxonomic studies are needed to evaluate the consistency of species concepts and interpretations of morphological features in a more global context. Reconstruction of ancestral states yielded two major evolutionary trends within section <it>Calochroi</it>: (1) the development of bright pigments evolved independently multiple times, and (2) the evolution of abruptly marginate to flattened stipe bulbs represents an autapomorphy of the <it>Calochroi </it>clade.</p

Imaging markers of disability in aquaporin-4 immunoglobulin G seropositive neuromyelitis optica: a graph theory study

Neuromyelitis optica spectrum disorders lack imaging biomarkers associated with disease course and supporting prognosis. This complex and heterogeneous set of disorders affects many regions of the central nervous system, including the spinal cord and visual pathway. Here, we use graph theory-based multimodal network analysis to investigate hypothesis-free mixed networks and associations between clinical disease with neuroimaging markers in 40 aquaporin-4-immunoglobulin G antibody seropositive patients (age = 48.16 ± 14.3 years, female:male = 36:4) and 31 healthy controls (age = 45.92 ± 13.3 years, female:male = 24:7). Magnetic resonance imaging measures included total brain and deep grey matter volumes, cortical thickness and spinal cord atrophy. Optical coherence tomography measures of the retina and clinical measures comprised of clinical attack types and expanded disability status scale were also utilized. For multimodal network analysis, all measures were introduced as nodes and tested for directed connectivity from clinical attack types and disease duration to systematic imaging and clinical disability measures. Analysis of variance, with group interactions, gave weights and significance for each nodal association (hyperedges). Connectivity matrices from 80% and 95% F-distribution networks were analyzed and revealed the number of combined attack types and disease duration as the most connected nodes, directly affecting changes in several regions of the central nervous system. Subsequent multivariable regression models, including interaction effects with clinical parameters, identified associations between decreased nucleus accumbens (β = −0.85, P = 0.021) and caudate nucleus (β = −0.61, P = 0.011) volumes with higher combined attack type count and longer disease duration, respectively. We also confirmed previously reported associations between spinal cord atrophy with increased number of clinical myelitis attacks. Age was the most important factor associated with normalized brain volume, pallidum volume, cortical thickness and the expanded disability status scale score. The identified imaging biomarker candidates warrant further investigation in larger-scale studies. Graph theory-based multimodal networks allow for connectivity and interaction analysis, where this method may be applied in other complex heterogeneous disease investigations with different outcome measures

Visual Analysis of Multiple Dynamic Sensitivities along Ascending Trajectories in the Atmosphere

Numerical weather prediction models rely on parameterizations for subgrid-scale processes, e.g., for cloud microphysics. These parameterizations are a well-known source of uncertainty in weather forecasts that can be quantified via algorithmic differentiation, which computes the sensitivities of prognostic variables to changes in model parameters. It is particularly interesting to use sensitivities to analyze the validity of physical assumptions on which microphysical parameterizations in the numerical model source code are based. In this article, we consider the use case of strongly ascending trajectories, so-called warm conveyor belt trajectories, known to have a significant impact on intense surface precipitation rates in extratropical cyclones. We present visual analytics solutions to analyze interactively the sensitivities of a selected prognostic variable, i.e. rain mass density, to multiple model parameters along such trajectories. We propose a visual interface that enables to a) compare the values of multiple sensitivities at a single time step on multiple trajectories, b) assess the spatio-temporal relationships between sensitivities and the shape and location of trajectories, and c) a comparative analysis of the temporal development of sensitivities along multiple trajectories. We demonstrate how our approach enables atmospheric scientists to interactively analyze the uncertainty in the microphysical parameterizations, and along the trajectories, with respect to a selected prognostic variable. We apply our approach to the analysis of convective trajectories within the extratropical cyclone "Vladiana", which occurred between 22-25 September 2016 over the North Atlantic