On Asymptotic Global Error Estimation and Control of Finite Difference Solutions for Semilinear Parabolic Equations

The aim of this paper is to extend the global error estimation and control addressed in Lang and Verwer [SIAM J. Sci. Comput. 29, 2007] for initial value problems to finite difference solutions of semilinear parabolic partial differential equations. The approach presented there is combined with an estimation of the PDE spatial truncation error by Richardson extrapolation to estimate the overall error in the computed solution. Approximations of the error transport equations for spatial and temporal global errors are derived by using asymptotic estimates that neglect higher order error terms for sufficiently small step sizes in space and time. Asymptotic control in a discrete $L_2$-norm is achieved through tolerance proportionality and uniform or adaptive mesh refinement. Numerical examples are used to illustrate the reliability of the estimation and control strategies

Overlay Accuracy Limitations of Soft Stamp UV Nanoimprint Lithography and Circumvention Strategies for Device Applications

In this work multilevel pattering capabilities of Substrate Conformal Imprint Lithography (SCIL) have been explored. A mix & match approach combining the high throughput of nanoimprint lithography with the excellent overlay accuracy of electron beam lithography (EBL) has been exploited to fabricate nanoscale devices. An EBL system has also been utilized as a benchmarking tool to measure both stamp distortions and alignment precision of this mix & match approach. By aligning the EBL system to 20 mm x 20 mm and 8 mm x 8 mm cells to compensate pattern distortions of order of $3 \mu m$ over 6 inch wafer area, overlay accuracy better than $1.2 \mu m$ has been demonstrated. This result can partially be attributed to the flexible SCIL stamp which compensates deformations caused by the presence of particles which would otherwise significantly reduce the alignment precision

Independent Information of Nonspecific Biomarkers in Exhaled Breath Condensate

Background: Exhaled breath condensate (EBC) has been used for diagnosing and monitoring respiratory disorders. For clinical purposes the assessment of easy-to-obtain nonspecific markers seems particularly interesting. Objectives: As these measures are related to each other, our objective was to extract the independent information in global EBC markers across a range of respiratory disorders. Methods: EBC was collected from patients with asthma (n = 18), chronic obstructive pulmonary disease (n = 17), and cystic fibrosis (n = 46), as well as from lung transplant (LTX) recipients (n = 14) and healthy controls (n = 26). Samples were assessed for electrical conductivity, ammonia, pH, and nitrite/nitrate. pH was measured after both deaeration with argon and CO(2) standardization. Additionally, the fraction of exhaled nitric oxide (FE(NO)) was assessed. Factor analysis was applied to identify major factors concerning these measures. Results: Three independent factors were detected; the first comprised conductivity, ammonia, and pH, especially when standardized using CO(2), the second nitrite/nitrate, and the third FE(NO). Conductivity and ammonia were highly correlated (r = 0.968; p < 0.001). FE(NO) provided independent information mainly in asthma. The nonspecific EBC markers showed considerable overlap between patient groups and healthy subjects. However, conductivity, ammonia, pH standardized for CO(2) and nitrite/nitrate were increased in LTX recipients compared to healthy controls (p < 0.05 each). Conclusions: A panel of nonspecific easy-to-obtain exhaled breath markers could be reduced to 3 independent factors. The information content of conductivity, ammonia, and pH after CO(2) equilibration appeared to be similar, while FE(NO) was independent. The increased levels of these biomarkers in LTX might indicate a potential for their use in these patients. Copyright (C) 2010 S. Karger AG, Base

Introduction

Évoquer la « Bourgogne », c’est mettre l’eau à la bouche des gourmets et des gourmands qui commencent à rêver du Kir, du Nuits-Saint-Georges, du Vosne-Romanée, du coq au vin, de la moutarde dijonnaise et des repas si délicieux préparés à la bourguignonne. Pour l’historien de l’art, c’est songer à Cluny, Tournus, Paray-le-Monial ou Autun, s’extasier au vu des œuvres de Rogier van der Weyden, de Jan van Eyck ou de Claus Sluter. Et qu’en est-il de ceux qui s’intéressent à l’histoire médiévale ? ..

Using 3D Spectroscopy to Probe the Orbital Structure of Composite Bulges

Detailed imaging and spectroscopic analysis of the centers of nearby S0 and spiral galaxies shows the existence of "composite bulges", where both classical bulges and disky pseudobulges coexist in the same galaxy. As part of a search for supermassive black holes in nearby galaxy nuclei, we obtained VLT-SINFONI observations in adaptive-optics mode of several of these galaxies. Schwarzschild dynamical modeling enables us to disentangle the stellar orbital structure of the different central components, and to distinguish the differing contributions of kinematically hot (classical bulge) and kinematically cool (pseudobulge) components in the same galaxy.Comment: LaTeX, 2 pages, 1 PDF figure. To appear in "Proceedings of IAU Symposium 309: Galaxies in 3D across the Universe", eds. B. L. Ziegler, F. Combes, H. Dannerbauer, and M. Verdug

Stochastic differential equations for evolutionary dynamics with demographic noise and mutations

We present a general framework to describe the evolutionary dynamics of an arbitrary number of types in finite populations based on stochastic differential equations (SDE). For large, but finite populations this allows to include demographic noise without requiring explicit simulations. Instead, the population size only rescales the amplitude of the noise. Moreover, this framework admits the inclusion of mutations between different types, provided that mutation rates, $\mu$, are not too small compared to the inverse population size 1/N. This ensures that all types are almost always represented in the population and that the occasional extinction of one type does not result in an extended absence of that type. For $\mu N\ll1$ this limits the use of SDE's, but in this case there are well established alternative approximations based on time scale separation. We illustrate our approach by a Rock-Scissors-Paper game with mutations, where we demonstrate excellent agreement with simulation based results for sufficiently large populations. In the absence of mutations the excellent agreement extends to small population sizes.Comment: 8 pages, 2 figures, accepted for publication in Physical Review

Der Einfluß der Änderung der lokalen Gewebeleitfähigkeit auf das Elektroenzephalogramm und das Magnetoenzephalogramm

We examined the influence of local tissue conductivity changes in the vicinity of a dipolar source on the neuromagnetic field and the electric scalp potential using a high resolution finite element method model of the human head. We found that the topology of both the electric scalp potential and the neuromagnetic field (and consequently dipole localization) is influenced significantly by conductivity changes only in voxels adjacent to the source. Conductivity changes in these voxels yield a greater change in the amplitude of the magnetic field (and consequently in the dipole strength) than in the amplitude of the electric potential.Der Einfluß der Änderung der lokalen Gewebeleitfahigkeit in der Nähe einer dipolaren Quelle auf das neuromagnetische Feld und das elektrische Potential wird mit Hilfe eines hochauflösenden Finite-Elemente-Modells des menschlichen Kopfes untersucht. Für Leitfähigkeitsänderungen in den Voxeln, die an der Quelle anliegen, wurde eine signifikante Änderung der Topologie (und demzufolge der Dipollokalisation) des magnetischen Feldes und des elektrischen Potentials gefunden. In diesen Voxeln führt die Leitfähigkeitsänderung zu größeren Änderungen in der Amplitude des magnetischen Feldes (und damit der Dipolstärke) als in der Amplitude des elektrischen Potentials

Der Einfluß der Änderung der Schalenleitfähigkeit bei Randelementemodellen auf die Vorwärtsrechnung und das inverse Problem in Elektroenzephalographie und Magnetoenzephalographie

Source localization based on magnetoencephalographic and electroencephalographic data requires knowledge of the conductivitiy values of the head. The aim of this paper is to examine the influence of compartment conductivity changes on the neuromagnetic field and the electric scalp Potential for the widely used three compartment boundary element models. Both the analysis of measurement data and the simulations with dipoles distributed in the brain produced two significant results. First, we found the electric potentials to be approximately one order of magnitude more sensitive to conductivity changes than the magnetic fields. This was valid for the field and Potential topology (and hence dipole localization), and for the amplitude (and hence dipole strength). Second, changes in brain compartment conductivity yield the lowest change in the electric potentials topology (and hence dipole localization), but a very strong change in the amplitude (and hence in the dipole strength). We conclude that for the magnetic field the influence of compartment conductivity changes is not important in terms of dipole localization and strength estimation. For the electric potentials however, both dipole localization and strength estimation are significantly influenced by the compartment conductivity.Die Gewebeleitfähigkeitswerte des Kopfes sind für Quellerdokalisationen, basierend auf magnetoenzephalographischen und elektroenzephalographischen Daten, erforderlich. Das Ziel dieser Arbeit besteht darin, den Einfluß von Leitfähigkeitsänderungen auf das neuromagnetische Feld und die elektrische Potentialverteilung auf der Kopfoberfläche für die weitverbreiteten 3-Schalen-Randelementemodelle zu untersuchen. Sowohl die Analyse von Meßdaten als auch die Simulationen mit im Gehirn verteilten Einzeldipolen führten zu zwei wesentlichen Ergebnissen. Erstens war die Empfindlichkeit gegenüber Leitfähigkeitsänderungen beim elektrischen Potential ungefähr eine Größenordnung höher als beim magnetischen Feld. Dies galt sowohl für die Topologie (und damit für die Dipollokalisation) als auch für die Amplitude (und damit für die Dipolstärke). Zweitens zeigten Leitfähigkeitsänderungen der innersten Schale (Gehirn) die geringsten Änderungen in der Topologie des elektrischen Potentials (und damit in der Dipollokalisation), aber dabei eine sehr starke Änderung in der Amplitude (und damit in der Dipolstärke). Es kann geschlußfolgert werden, daß der Einfluß der Leitfähigkeitsänderung auf die Dipollokalisation und die Bestimmung der Dipolstärke aus dem magnetischen Feld vernachlässigt werden kann. Die Berechnung von Dipolort und -stärke aus dem elektrischen Potential ist jedoch signifikant von der Leitfähigkeit der Schalen abhängig

Looking for residues of pesticides in bees, plants and bee products

Die chemisch-analytische Bestimmung von Schadstoff-Rückständen verschiedenen Ursprungs ist essentiell für die Expositionsermittlung im Rahmen der Aufklärung von Bienenvergiftungen und von Studien zur Bewertung des Risikos für Bienen. Die etablierte und umfassend validierte Multimethode ist sowohl zur Bestimmung von Rückständen in Bienen- und Pflanzenproben als auch für diverse Bienenprodukte (z.B. Pollen/Bienenbrot, Gelée Royal oder Wachs) sehr gut geeignet. Die Zusatzversuche zur Methodenüberprüfung wurden mit dem jeweils aktuellen Wirkstoffspek­trum der Untersuchungsstelle für Bienenvergiftungen und verschiedenen Zusatzkonzentrationen durchgeführt. Die Zusatzkonzentrationen wurden so gewählt, dass möglichst alle Wirkstoffe des Untersuchungsprogramms sowohl mit LC‑MS/MS als auch mit GC‑MS bestimmt werden konnten. Mit den Matrices „Bienen“ und „Raps“ wurden Vali­dierungen mit den Konzentration 1, 10 und 50 μg/kg durchgeführt. Die Quantifizierung wurde mit Matrix-Standards vorgenommen, um die durch Probeninhaltsstoffe hervorgerufenen Matrixeinflüsse zu reduzieren.Für 240 Wirkstoffe (vor allem Insektizide, Fungizide), die 2011 im Screening-Programm enthalten waren, lagen die Wiederfindungsraten mit Bienenmatrix beim Zusatzniveau von 10 μg/kg überwiegend zwischen 70% und 110%, mit relativen Standardabweichungen unter 15%.The chemical-analytical determination of pollutant residues of various origins is essential for the determination of exposure in the context of the investigation of bee poisoning and of studies to assess the risk to bees. The established and extensively validated multi-method is very well suited for the determination of residues in bee and plant samples as well as for various bee products (e.g. pollen/bee bread, royal jelly or wax). The validation experiments were carried out with the current spectrum of active substances of the investigation center for bee poisoning incidents and various concentration levels. The concentrations were chosen so that as far as possible all active substances of the investigation program could be determined with LC-MS/MS and GC-MS. Validations with the concentrations 1, 10 and 50 μg/kg were carried out with the matrices “bees” and “rape”. The quantification was carried out with matrix standards in order to reduce the matrix influences caused by sample ingredients. For 240 active substances (especially insecticides, fungicides), included in the screening program in 2011, the recovery rates with the bee matrix at the concentration level of 10 μg/kg were mostly between 70% and 110%, with relative standard deviations below 15%