Unusual synchronization phenomena during electrodissolution of silicon: the role of nonlinear global coupling

The photoelectrodissolution of n-type silicon constitutes a convenient model system to study the nonlinear dynamics of oscillatory media. On the silicon surface, a silicon oxide layer forms. In the lateral direction, the thickness of this layer is not uniform. Rather, several spatio-temporal patterns in the oxide layer emerge spontaneously, ranging from cluster patterns and turbulence to quite peculiar dynamics like chimera states. Introducing a nonlinear global coupling in the complex Ginzburg-Landau equation allows us to identify this nonlinear coupling as the essential ingredient to describe the patterns found in the experiments. The nonlinear global coupling is designed in such a way, as to capture an important, experimentally observed feature: the spatially averaged oxide-layer thickness shows nearly harmonic oscillations. Simulations of the modified complex Ginzburg-Landau equation capture the experimental dynamics very well.Comment: To appear as a chapter in "Engineering of Chemical Complexity II" (eds. A.S. Mikhailov and G.Ertl) at World Scientific in Singapor

Conditional quasi-exact solvability of the quantum planar pendulum and of its anti-isospectral hyperbolic counterpart

We have subjected the planar pendulum eigenproblem to a symmetry analysis with the goal of explaining the relationship between its conditional quasi-exact solvability (C-QES) and the topology of its eigenenergy surfaces, established in our earlier work [Frontiers in Physical Chemistry and Chemical Physics 2, 1-16, (2014)]. The present analysis revealed that this relationship can be traced to the structure of the tridiagonal matrices representing the symmetry-adapted pendular Hamiltonian, as well as enabled us to identify many more -- forty in total to be exact -- analytic solutions. Furthermore, an analogous analysis of the hyperbolic counterpart of the planar pendulum, the Razavy problem, which was shown to be also C-QES [American Journal of Physics 48, 285 (1980)], confirmed that it is anti-isospectral with the pendular eigenproblem. Of key importance for both eigenproblems proved to be the topological index $\kappa$, as it determines the loci of the intersections (genuine and avoided) of the eigenenergy surfaces spanned by the dimensionless interaction parameters $\eta$ and $\zeta$. It also encapsulates the conditions under which analytic solutions to the two eigenproblems obtain and provides the number of analytic solutions. At a given $\kappa$, the anti-isospectrality occurs for single states only (i.e., not for doublets), like C-QES holds solely for integer values of $\kappa$, and only occurs for the lowest eigenvalues of the pendular and Razavy Hamiltonians, with the order of the eigenvalues reversed for the latter. For all other states, the pendular and Razavy spectra become in fact qualitatively different, as higher pendular states appear as doublets whereas all higher Razavy states are singlets

Development of a jet gas target system for the Felsenkeller underground accelerator

For direct cross-section measurements in nuclear astrophysics, in addition to suitable ion beams and detectors, also highly pure and stable targets are needed. Here, using a gas jet as a target offers an attractive approach that combines high stability even under significant beam load with excellent purity and high localisation. Such a target is currently under construction at the Felsenkeller underground ion accelerator lab for nuclear astrophysics in Dresden, Germany. The target thickness will be measured by optical interferometry, allowing an in-situ thickness determination including also beam-induced effects. The contribution reports on the status of this new system and outlines possible applications in nuclear astrophysics.Comment: Submitted to Nuclear Physics in Astrophysics - X conference proceedin

Experimente zur Entstehung von Titan-44 in Supernovae

In dieser Diplomarbeit wurde das astrophysikalisch interessante Resonanztriplett der Reaktion 40Ca(α,γ)44Ti bei 4,5MeV untersucht. Am 3-MV-Tandetron des Helmholtz-Zentrums Dresden-Rossendorf wurden dafür die Energien von Protonen- und -Strahlen kalibriert, Anregungsfunktionen im Energiebereich der drei Resonanzen aufgenommen, vier CaOTargets aktiviert und deren Struktur mittels der Reaktion 40Ca(p,γ)41Sc überprüft. Im Felsenkeller-Niederniveaumesslabor wurde anschließend die Aktivität der Proben gemessen. Schließlich konnte die Summe der Resonanzstärken bei 4497 und 4510 keV -Energie im Laborsystem zu (12;8 2;3) eV und die Summe der Resonanzstärken des gesamten Tripletts, d.h. zusätzlich bei 4523 keV, zu (12;0 2;0) eV bestimmt werden. Bei der ersten Resonanzstärke konnte die Unsicherheit im Vergleich zur Literatur von 19% auf 18% verbessert werden. Außerdem bieten die Daten der vorliegenden Arbeit die Grundlage, zukünftig die Unsicherheiten noch erheblich weiter zu reduzieren.In this thesis the astrophysically interesting resonance triplet of the 40Ca(α ,γ)44Ti reaction at 4.5MeV has been studied. For this purpose energies of proton and beams provided by 3MVTandetron at Helmholtz-Zentrum Dresden-Rossendorf have been calibrated. Excitation functions of energy regions near the resonances and in-beam spectra of four different targets have been measured. The 40Ca(p,γ)41Sc reaction has been used to scan the structure of the activated targets. Afterwards their activity has been measured in the underground laboratory Felsenkeller Dresden. Hence the sum of resonance strengths at laboratory energies of 4497 and 4510 keV of (12:8 2:3) eV has been determined as well as the sum of the total triplet strength, including 4523 keV, of (12:0 2:0) eV. In the case of the first resonance, the uncertainty was decreased from 19% to 18 %. Furthermore the results of this work establish a basis for reaching much lower uncertainties in the future

Die Grabwespen-Typen A. Schencks in der Sammlung C. L. Kirschbaum im Landesmuseum Wiesbaden (Hymenoptera: Sphecidae).

In der Sammlung C. L. Kirschbaum, die im Landesmuseum Wiesbaden aufbewahrt wird, konnten einige verschollene Grabwespen-Typen A. Schencks wieder aufgefunden werden. In der folgenden Zusammenstellung steht der gültige Name an erster Stelle: Nysson maculatus (Fabricius, 1793) = Nysson lineolatus Schenck, 1857, Weibchen; Tachysphex obscuripennis (Schenck, 1857) = Tachytes lativalvis Thomson, 1870; Psenulus fulvicornis (Schenck, 1857) sp. propr.?; Ectemnius lituratus (Panzer, 1804) = Crabro argenteus Schenck, 1857, Weibchen; Ectemnius guttatus (van der Linden, 1829) = Crabro pictus Schenck, 1857, Weibchen. Nomenklatorische Handlungenpictus Schenck, 1857 (Crabro (Ectemnius)), syn. n. of Ectemnius guttatus (van der Linden, 1829)lineolatus Schenck, 1857 (Nysson), syn. n. of Nysson maculatus (Fabricius, 1793)lativalvis Thomson, 1870 (Tachytes), syn. n. of Tachytes obscuripennis Schenck, 1857In the collection C. L. Kirschbaum, which is now kept at Landesmuseum Wiesbaden there were found some missing digger wasp types of A. Schenck. In the following the valid names are given first: Nysson maculatus (Fabricius, 1793) = Nysson lineolatus Schenck, 1857, female; Tachysphex obscuripennis (Schenck, 1857) = Tachytes lativalvis Thomson, 1870; Psenulus fulvicornis (Schenck, 1857) sp. propr.?; Ectemnius lituratus (Panzer, 1804) = Crabro argenteus Schenck, 1857, female; Ectemnius guttatus (van der Linden, 1829) = Crabro pictus Schenck, 1857, female.Nomenclatural Actspictus Schenck, 1857 (Crabro (Ectemnius)), syn. n. of Ectemnius guttatus (van der Linden, 1829)lineolatus Schenck, 1857 (Nysson), syn. n. of Nysson maculatus (Fabricius, 1793)lativalvis Thomson, 1870 (Tachytes), syn. n. of Tachytes obscuripennis Schenck, 185

Automatisierte Generierung und Simulation von Hyper-Heuristiken für stochastische Multi-Modus-Multi-Projekt-ressourcenbeschränkte Projekt- und Systemplanungsprobleme mit Umrüstzeiten

A simulation framework is presented which covers both generation and simulation of production planning and control problems which include transfer times and stochastic influences and therefore extend classical multi-mode multi-project RCPSPs. This allows for systematic and in-depth investigations of the quality and the behaviour of heuristics. In addition, the automated design of heuristics based on Boolean operators applied to relations of problem specific quantities leads on average to better results than a manual selection and adjustment of heuristic strategies

Registered cartels in Austria: An overview

Cartels were legal to a large extent in Austria until the country's EU Accession in 1995. We examine archival material on registered horizontal cartels to learn about their inner working. Applying content analysis to legally binding cartel contracts, we comprehensively document different collusion methods along the lines described by Stigler (1964). Quota cartels employ regular reporting schemes and use compensation mechanisms for departures from set quotas. Specialization cartels divide markets, and rely the least on information exchange and punishment. Price and payment condition cartels primarily aim to prevent secret price cuts, requiring information provision upon request, allow for discretionary decision-taking and (sometimes immediate) punishment. These stylized facts on the contractual arrangements suggest that the possibility to write legally binding agreements was employed to address the usual obstacles to sustaining collusion

Registered Cartels in Austria. An Overview

Cartels were legal to a large extent in Austria until the country's EU accession in 1995. We examine archival material on registered horizontal cartels to learn about their inner working. Applying content analysis to legally binding cartel contracts, we comprehensively document different collusion methods along the lines described by Stigler (1964). Quota cartels employ regular reporting schemes and use compensation mechanisms for departures from set quotas. Specialisation cartels divide markets and rely the least on information exchange and punishment. Price and payment condition cartels primarily aim to prevent secret price cuts, requiring information provision upon request, allow for discretionary decision-taking and (sometimes immediate) punishment. These stylised facts on the contractual arrangements suggest that the possibility to write legally binding agreements was employed to address the usual obstacles to sustaining collusion

Factors influencing the presence of Candida dubliniensis and other non-albicans species in patients with oral lichen planus: a retrospective observational study

Objectives: The epidemiologic distribution of non-albicans species in the oral cavity of oral lichen planus (OLP) patients remains uncertain. Therefore, the aim of this study was to identify factors associated with the presence of C. dubliniensis and other non-albicans species. Furthermore, independent risk factors for Candida superinfection in OLP should be identified. Material and methods: Epidemiologic data and microbiological findings from 268 symptomatic OLP patients who underwent continuous oral swab culture over a 5-year period (2015-2019) were retrospectively reviewed. Candida species identification and semi-quantification were obtained by culture on CHROMagar Candida, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Results: C. albicans was the most frequently isolated species (72.3%), followed by C. glabrata (7.3%), C. dubliniensis (5.8%), C. krusei and C. parapsilosis (both 2.6%). The presence of C. dubliniensis was significantly associated with tobacco smoking. Other non-albicans spp. were significantly more often detected in patients using removable dentures. Increasing age and the intake of psychotropic drugs were identified as independent risk factors of Candida superinfection in OLP. Conclusion: In OLP patients, certain local and systemic factors increase the risk of carrying potentially drug-resistant Candida species and the development of Candida superinfection of OLP lesions. Clinical relevance: Due to the frequent detection of non-albicans species in OLP, resistance or at least reduced sensitivity to azole antifungals should be expected, especially in smokers and patients using removable dentures. In the case of oral complaints, a superinfection with Candida should be considered, whereby older patients and patients taking psychotropic drugs have an increased risk for oral infection with Candida

Induction of Gynogenesis in Muskellunge With Irradiated Sperm of Yellow Perch Proves Diploid Muskellunge Male Homogamety

Diploid gynogenesis was induced in muskellunge Esox masquinongy using UV-irradiated muskellunge sperm as the first step in producing monosex females. In this approach, we have to rely on negative controls as an indirect reference for sperm genetic material destruction. In the first experiment, equal proportions of gynogenetic females and males were produced. Negative controls, UV-irradiated sperm without heat shock, yielded some normal hatching larvae, described as spontaneous diploids. In the second experiment, muskellunge eggs were activated using sperm from yellow perch. Because hybrids between these species are not viable, we produced unambiguous gynogens. When UV-irradiated yellow perch sperm was used to inseminate muskellunge eggs, haploids resulted (22.5% ± 2.8% survival to the eyed stage). To produce diploid gynogens, a heat shock of 31°C was applied to inseminated eggs 20 min after activation for a duration of 6 min. This process yielded several hundreds of gynogens for rearing. Several treatments of masculinizing hormone, 17 α-methyltestosterone (MT), were carried out. Fish were dissected and gonads examined histologically for sex determination. Gynogens produced using yellow-perch sperm confirmed the presence of males in the control group, whereas the MT bath treatment (400 μg/liter) resulted in the production of fish with ovotestis. These results provide evidence for male homogamety in muskellunge and imply that a change of strategy is needed to produce monosex populations.Funding for this project was provided by the Federal Aid in Sport Fish Restoration Program (F-69-P, Fish Management in Ohio), administered jointly by the U.S. Fish and Wildlife Service and the Ohio Division of Wildlife