Synthetic X-ray and radio maps for two different models of Stephan's Quintet

We present simulations of the compact galaxy group Stephan's Quintet (SQ) including magnetic fields, performed with the N-body/smoothed particle hydrodynamics (SPH) code \textsc{Gadget}. The simulations include radiative cooling, star formation and supernova feedback. Magnetohydrodynamics (MHD) is implemented using the standard smoothed particle magnetohydrodynamics (SPMHD) method. We adapt two different initial models for SQ based on Renaud et al. and Hwang et al., both including four galaxies (NGC 7319, NGC 7320c, NGC 7318a and NGC 7318b). Additionally, the galaxies are embedded in a magnetized, low density intergalactic medium (IGM). The ambient IGM has an initial magnetic field of $10^{-9}$ G and the four progenitor discs have initial magnetic fields of $10^{-9} - 10^{-7}$ G. We investigate the morphology, regions of star formation, temperature, X-ray emission, magnetic field structure and radio emission within the two different SQ models. In general, the enhancement and propagation of the studied gaseous properties (temperature, X-ray emission, magnetic field strength and synchrotron intensity) is more efficient for the SQ model based on Renaud et al., whose galaxies are more massive, whereas the less massive SQ model based on Hwang et al. shows generally similar effects but with smaller efficiency. We show that the large shock found in observations of SQ is most likely the result of a collision of the galaxy NGC 7318b with the IGM. This large group-wide shock is clearly visible in the X-ray emission and synchrotron intensity within the simulations of both SQ models. The order of magnitude of the observed synchrotron emission within the shock front is slightly better reproduced by the SQ model based on Renaud et al., whereas the distribution and structure of the synchrotron emission is better reproduced by the SQ model based on Hwang et al..Comment: 20 pages, 15 figures, accepted to MNRA

The KATRIN Experiment

The KArlsruhe TRitium Neutrino mass experiment, KATRIN, aims to search for the mass of the electron neutrino with a sensitivity of 0.2 eV/c^2 (90% C.L.) and a detection limit of 0.35 eV/c^2 (5 sigma). Both a positive or a negative result will have far reaching implications for cosmology and the standard model of particle physics and will give new input for astroparticle physics and cosmology. The major components of KATRIN are being set up at the Karlsruhe Institut of Technology in Karlsruhe, Germany, and test measurements of the individual components have started. Data taking with tritium is scheduled to start in 2012.Comment: 3 pages, 1 figure, proceedings of the TAUP 2009 International Conference on Topics in Astroparticle and Underground Physics, to be published in Journal of Physics, Conference Serie

Magnetic buoyancy in simulated galactic discs with a realistic circum galactic medium

We present simulations of isolated disc galaxies in a realistic environment performed with the Tree-SPMHD-Code Gadget-3. Our simulations include a spherical circum-galactic medium (CGM) surrounding the galactic disc, motivated by observations and the results of cosmological simulations. We present three galactic models with different halo masses between 10e10 Msol and 10e12 Msol, and for each we use two different approaches to seed the magnetic field, as well as a control simulation without a magnetic field. We find that the amplification of the magnetic field in the centre of the disc leads to a biconical magnetic outflow of gas that magnetizes the CGM. This biconical magnetic outflow reduces the star formation rate (SFR) of the galaxy by roughly 40 percent compared to the simulations without magnetic fields. As the key aspect of our simulations, we find that small scale turbulent motion of the gas in the disc leads to the amplification of the magnetic field up to tens of 10e-6 G, as long as the magnetic field strength is low. For stronger magnetic fields turbulent motion does not lead to significant amplification but is replaced by an alpha-omega dynamo. The occurance of a small scale turbulent dynamo becomes apparent through the magnetic power spectrum and analysis of the field lines' curvature. In accordance with recent observations we find an anti-correlation between the spiral structure in the gas density and in the magnetic field due to a diffusion term added to the induction equation.Comment: 22 pages, 16 figures, submitted to MNRA

Cloudifying Desktops – A Taxonomy for Desktop Virtualization

Compared to traditional desktops, the implementation of desktop virtualization can leverage cost reductions and enable desktop access via mobile devices. Consequently, researchers and practitioners increasingly focus on virtualized desktops and Desktop as a Service (DaaS). However, a consistent definition for these technologies and the related delivery models does not exist yet. Therefore, we conducted a literature analysis which revealed that optimized resource allocation and performant DaaS infrastructures are the primary topics in research. Afterward, we developed a taxonomy to categorize extant virtual desktop delivery models and propose a holistic definition as theoretical framework for DaaS

Die Steinartefakte aus dem Großen Schulerloch (Grabung Birkner 1915). Zur Rekonstruktion von Inventaren sowie zur Frage der kulturellen und chronologischen Einordnung eines alt gegrabenen Fundmaterials auf der Basis archäologischer Methoden

The thesis is based on the lithic artefacts excavated by Prof. Ferdinand Birkner in 1915. The combined analysis of raw material variants and work pieces, informations about stratigraphic positions of the finds, and various documents such as the original record of the excavators revealed that it is unlikely that the lithics had been found in primary condition. It can be proposed, however, that the sediments containing the lithics had originally been situated at the entrance of the cave and had been used to level the cave floor during the works conducted in the jears 1826-28. These works led to fundamental changes of the entrance area to ease access into the cave. Detailed typological and technological comparisions between the Schulerloch artefacts and 25 Middle Palaeolithic assemablages in the neighbourhood showed that tere are particular similarities with the inventories from the G-Layers of the Sesselfelsgrotte. The total amount of lithic artefacts yielded in the sediments of the Schulerloch Cave can be projected to 10000 or even more pieces > 2 cm perhaps belonging to assemblages similar to those of the G-Layers. The artefacts from Schulerloch Cave are the last bits of supposedly once more complete parts of chaine operatoires giving glimpses at the human cave use in the Middle Palaeolithic. A lot of different sporadic occupations can be reconstructed most of them characterised by the import of prepared cores and further knapping and preparation of the cores. Based on the similarities with the G-Layers of the Sesselfelsgrotte and also other sites the main part of the Schulerloch assemblage is supposed to date to the Interpleniglacial.Grundlage der vorliegenden Arbeit ist das lithische Fundmaterial aus dem Großen Schulerloch, Ldkr. Kelheim, wie es im Jahr 1999 im Magazin der Archäologischen Staatssammlung München vorgefunden wurde. Es stammt zu wesentlichen Teilen aus der Grabung Ferdinand Birkners von 1915, wenige Stücke waren bei den Schürfungen Alexander Oberneders in den Jahren davor geborgen worden; einzelne Stücke aus dem Privatbesitz der Höhleneigentümer ergänzen diesen Bestand. Es ist wahrscheinlich, daß die Fundstücke in der Höhle nicht in situ angetroffen wurden, sondern daß die Grabungen Oberneders und Birkners in umgelagertem Sediment stattfanden. Hinweise dafür lieferte unter anderem die Kombination der Positionsangaben auf den Fundstücken mit der Werkstückanalyse. Durch diese Methodik war es möglich, trotz der Unvollständigkeit des überlieferten Bestandes, ein ungefähres Bild von der Verteilung der Artefakte zum Zeitpunkt der Ausgrabung zu bekommen. Diese Rekonstruktion der Fundverhältnisse lieferte die notwendige Vorarbeit für die archäologische Bearbeitung des Fundmaterials, das auf der Grundlage formenkundlicher, typologischer und technologischer Merkmale mit 25 ausgewählten Vergleichsinventaren aus der nahen Umgebung der Fundstelle in Beziehung gesetzt wurde. Das wichtigste auf diesem Weg gewonnene Ergebnis ist, daß der Fundbestand aus dem Großen Schulerloch in seiner Masse den mittelpaläolithischen G-Schichten der Sesselfelsgrotte nahesteht. Vermutlich hat das Schulerloch ehemals einen Niederschlag von 10.000 - 13.000 Artefakten >2cm enthalten, was etwa dem halben Umfang der G-Schichten entspricht. Als Kristallisationspunkt der Parallelen und Übereinstimmungen ließ sich ein als „Kerninventar“ bezeichneter Bestand herausarbeiten. Er umfaßt 415 Artefakte, die in ihren typologisch-morphologisch-technologischen Charakteristika mit den G-Schichten weitgehend übereinstimmen. Das Kerninventar kann mehrere Inventare bzw. Teile davon umfassen, die aber nicht zu trennen waren. Es ist auf den Abbau und die Korrektur vorpräparierter und bereits teilweise abgebauter Kerne zurückzuführen. Belegt sind verschiedene typisch mittelpaläolithische Abbaukonzepte, wobei das diskoide Konzept weitgehend auf Kreidesilices beschränkt ist, während sich das Levalloiskonzept auf Juramaterialien konzentriert. Letzteres kommt mit einigen Varianten vor, wobei die zentripetale Methode nicht durch Restkerne belegt ist. Ein Teil der Werkzeuge wurde importiert. Das Kerninventar bildet die episodenhafte Nutzung der Fundstelle ab, längere und durchgehende Aufenthalte sind nicht wahrscheinlich. Vorgeschlagen wird eine Datierung des Kerninventars und damit des archäologisch faßbaren Schwerpunktes des Materials aus dem Großen Schulerloch in einen älteren Abschnitt des Interpleniglazials – in die Zeit zwischen 45.000 und 55.000 vor Heute

A Review of International Recommendations for the Diagnosis and Management of Chronic Urticaria

Both spontaneous and inducible forms of chronic urticaria pose a significant economic burden and have an adverse effect on patients’ quality of life. The international guidelines and US practice parameters for the diagnosis and management of chronic urticaria both recommend performing a thorough patient history and physical examination, conducting limited routine laboratory testing, and taking a stepwise approach to treatment. These documents differ in several areas, such as the order of diagnostic procedures and the treatment for patients non-responsive to standard dose H1-antihistamines. Patients with chronic urticaria who visit a specialist have typically been treated with second-generation H1-antihistamines – the recommended first-line treatments. The advantages and disadvantages of each treatment option should be taken into consideration when selecting therapies beyond H1-antihistamines. Greater awareness of the international guidelines and US practice parameters will likely improve the quality of care for patients with chronic urticaria

Subjective and objective accommodation of the Crystalens Advanced Optics (AO) in patients 6 months after bilateral implantation

Background: The aim of this study was to analyze and compare objective and subjective accommodation in patients after bilateral implantation of the FDA-approved accommodating Crystalens Advanced Optics (AO). Material and methods: This study was performed on 8 eyes of 4 patients. The subjective accommodation was measured by monocular and binocular defocus curves under photopic and mesopic conditions. The objective accommodation was analyzed using partial coherence interferometry (PCI) and wavefront aberration. Pupil diameter at different set-ups and refraction were derived from wavefront data. Results: Uncorrected and corrected distance and uncorrected near visual acuity improved significantly following implantation of the Crystalens AO in all eyes. Only one patient needed spectacles to correct distance visual acuity. Mean distance uncorrected visual acuity was 0.05 ± 0.06 logMAR. All patients were able to read newspapers without spectacles. Mean near uncorrected visual acuity was 0.17 ± 0.12 logMAR. Subjective accommodative amplitude under photopic conditions was significantly better binocularly than monocularly (p = 0.03) and was significant worse monocularly under mesopic conditions than photopic conditions (p = 0.016). No significant changes in anterior chamber depth were observed by PCI, with a fixation on optical stimuli at different distances. There were also no significant changes in the wavefront aberrations between the different set-ups. Pupil diameter increased significantly in the near set-up under mesopic conditions. Conclusions: No objective change in lens configuration was observed under different set-ups. Due to a variety of factors involved in pseudoaccommodation (e.g. pupil diameter, astigmatism, and multifocality), the subjective accommodative amplitude tends to be overestimated relative to objective measurements. No real accommodative action was observed

Water Quality Trends Following Anomalous Phosphorus Inputs to Grand Bay, Mississippi, USA

Grand Bay National Estuarine Research Reserve (GBNERR) is a 7500 ha protected area in Jackson County, MS. In 2005, a levee breach at a fertilizer manufacturing facility released highly acidic and phosphate—rich wastewater into the reserve. A second spill occurred in September 2012 following Hurricane Isaac. We used orthophosphate (PO43-) concentrations to categorize the 2 events, post— events, and non—impact periods between the 2 spills. We examined spatial and temporal patterns in nutrients, chlorophyll, pH, and other parameters within and between monitoring stations. After the first event, pH at the Bangs Lake water quality station decreased to 3.7 and PO43- increased to over 4 mg P/l. Orthophosphate returned to background concentrations near the detection limit after approximately one year. Sampling 3 weeks after Hurricane Isaac showed PO43- concentrations over 1 mg P/l in Bangs Lake. Elevated PO43- levels were detected at other monitoring locations for 3—5 months, depending on distance from the fertilizer facility. Multiple comparison tests of trends within stations showed that both events had statistically similar PO43- concentrations, although the magnitudes and the time to return to baseline concentrations differed between stations. Temporal patterns of other nutrients had apparent long—term trends, particularly chlorophyll a, which showed an increase from 18—56% depending on station. This study provides a rare description of decadal water quality trends in a shallow, temperate estuary in response to discrete spill events. The results provide new information on the effects of phosphorus inputs to nitrogen—limited systems, having management implications for Gulf Coast estuaries

NeuralNetTools: Visualization and Analysis Tools for Neural Networks

Supervised neural networks have been applied as a machine learning technique to identify and predict emergent patterns among multiple variables. A common criticism of these methods is the inability to characterize relationships among variables from a fitted model. Although several techniques have been proposed to "illuminate the black box", they have not been made available in an open-source programming environment. This article describes the NeuralNetTools package that can be used for the interpretation of supervised neural network models created in R. Functions in the package can be used to visualize a model using a neural network interpretation diagram, evaluate variable importance by disaggregating the model weights, and perform a sensitivity analysis of the response variables to changes in the input variables. Methods are provided for objects from many of the common neural network packages in R, including caret, neuralnet, nnet, and RSNNS. The article provides a brief overview of the theoretical foundation of neural networks, a description of the package structure and functions, and an applied example to provide a context for model development with NeuralNetTools. Overall, the package provides a toolset for neural networks that complements existing quantitative techniques for data-intensive exploration