Wave number-Explicit Analysis for Galerkin Discretizations of Lossy Helmholtz Problems

We present a stability and convergence theory for the lossy Helmholtz equation and its Galerkin discretization. The boundary conditions are of Robin type. All estimates are explicit with respect to the real and imaginary part of the complex wave number $\zeta\in\mathbb{C}$, $\operatorname{Re}\zeta\geq0$, $\left\vert \zeta\right\vert \geq1$. For the extreme cases $\zeta \in\operatorname*{i}\mathbb{R}$ and $\zeta\in\mathbb{R}_{\geq0}$, the estimates coincide with the existing estimates in the literature and exhibit a seamless transition between these cases in the right complex half plane.Comment: 29 pages, 1 figur

"It's the real thing": performance and murder in Sweden.

The article investigates contemporary experimental theatre in Sweden. It sums up and probes the implications of Sju tre (1999), the most controversial theatre production in Sweden in modern times. Lars Nor'n, the playwright and director, staged a dialogue involving three real convicts, of whom two were outspoken Nazis. The article explores the uncertain boundaries between aesthetic, ethical, and political issues with ramifications regarding the wider public opinion in Sweden, on racism and crime. It is methodologically motivated by reception research, performativity and idealogical discourse. By virtue of its performative impact, the theatrical event proved to be directly linked with critical questions of democracy, although conceivably at the expense of the artistic integrity of the director and the theatre as creator of public opinion. The article points to a paradox of democracy whereby hate speech is at once allowed and unjustified in the theatre as national arena. The actors are described and analysed as parasites in a societal body, that in Sju tre, becomes politically epitomised

Towards the spatial resolution of metalloprotein charge states by detailed modeling of XFEL crystallographic diffraction.

Oxidation states of individual metal atoms within a metalloprotein can be assigned by examining X-ray absorption edges, which shift to higher energy for progressively more positive valence numbers. Indeed, X-ray crystallography is well suited for such a measurement, owing to its ability to spatially resolve the scattering contributions of individual metal atoms that have distinct electronic environments contributing to protein function. However, as the magnitude of the shift is quite small, about +2 eV per valence state for iron, it has only been possible to measure the effect when performed with monochromated X-ray sources at synchrotron facilities with energy resolutions in the range 2-3 × 10-4 (ΔE/E). This paper tests whether X-ray free-electron laser (XFEL) pulses, which have a broader bandpass (ΔE/E = 3 × 10-3) when used without a monochromator, might also be useful for such studies. The program nanoBragg is used to simulate serial femtosecond crystallography (SFX) diffraction images with sufficient granularity to model the XFEL spectrum, the crystal mosaicity and the wavelength-dependent anomalous scattering factors contributed by two differently charged iron centers in the 110-amino-acid protein, ferredoxin. Bayesian methods are then used to deduce, from the simulated data, the most likely X-ray absorption curves for each metal atom in the protein, which agree well with the curves chosen for the simulation. The data analysis relies critically on the ability to measure the incident spectrum for each pulse, and also on the nanoBragg simulator to predict the size, shape and intensity profile of Bragg spots based on an underlying physical model that includes the absorption curves, which are then modified to produce the best agreement with the simulated data. This inference methodology potentially enables the use of SFX diffraction for the study of metalloenzyme mechanisms and, in general, offers a more detailed approach to Bragg spot data reduction

Diagnostik von Motilitätsstörungen von Ösophagus und Magen

Zusammenfassung: Motilitätsstörungen von Ösophagus und Magen sind eine häufige Ursache für Symptome des oberen Gastrointestinaltrakts. Eine gestörte ösophageale Motorik führt zu einem beeinträchtigten Bolustransport, pathologischem gastroösophagealem Reflux und/oder einer verminderten Ösophagus-Clearance refluierten Mageninhalts. Diese Pathomechanismen können u.a. Dysphagie, retrosternale Schmerzen und Refluxbeschwerden verursachen. Das Wissen über die Vor- und Nachteile der verschiedenen Untersuchungsmethoden sowie der relevanten Pathophysiologie ist für eine zielgerichtete und effiziente diagnostische Abklärung unerlässlich. Die Magenfunktion ist die Folge einer Kombination aus Magenstruktur, Motilität sowie neurohumoralen, die Magenmotilität steuernden Rückkopplungsmechanismen. Eine gestörte Magenfunktion kann zu vorzeitigem Sättigungsgefühl, Übelkeit bzw. Erbrechen und in ausgeprägten Fällen auch Gewichtsverlust führen. Ein Globaltest zur Beurteilung der Magenfunktion existiert nicht. Neben der Szintigraphie, dem aktuellen Goldstandard, gibt es eine Vielzahl an diagnostischen Untersuchungsmethoden zur Erfassung von Teilaspekten der Magenfunktion wie 13C-Atemteste oder auch die Magnetresonanztomographie, deren Anwendungsbereiche und Limitationen erläutert werde