Active tectonics of the Lower Rhine Graben (NW Central Europe)

Identification of active seismogenic faults in low-strain intraplate regions is a major challenge. The understanding of intraplate earthquakes is hampered by the spatiotemporal scattering of large earthquakes and by barely detectable strain accumulation. In populated humid regions, both hillslope and anthropogenic processes are important challenges to the recognition of potentially active faults. The Lower Rhine Graben is the NW segment of the European Cenozoic Rift System. It is a prime example of a seismically active low-strain rift situated in a humid and densely populated region. The approximate location of potentially active fault segments in this region is well known, but knowledge of the recurrence of large earthquakes and of the dominant fault slip mode is still rudimentary. The current debate ranges from slip dominated by repeated large earthquakes to slip dominated by aseismic creep. The purpose of this thesis is to determine whether the Lower Rhine Graben is an exception to the usually observed deformational behaviour of the upper crust, whereby active faults fail by brittle behaviour. The thesis addresses the Holocene, historical and present-day tectonic activity of the Lower Rhine Graben. It examines the signs of coseismic deformation in the geological record, and the surface expression of active fault segments. I analyzed high-resolution LiDAR terrain models of segments of the Erft and Wissersheimer faults, in order to understand the preservation potential of active fault scarps in populated, humid settings. Results of the LiDAR analysis illustrate that the central part of the Lower Rhine Graben is characterized by severe degradation and modification of suspected seismogenic structures. Degradation is due to fluvial erosion, hillslope processes and anthropogenic overprint. This analysis shows, also for the first time, the severity of surface modification of the region resulting from aerial bombing during World War II. A large trench excavation at the Schafberg fault in Holocene sediments yielded a broadly distributed fault zone with a peculiar abundance of fractured clasts. A particular question at this site is whether or not the fault ruptured in the 1756 AD Düren event. The excavation reveals the first evidence of historical seismogenic faulting in the Lower Rhine Graben. Coseismic deformation at this site is expressed by a net vertical displacement of 1 ± 0.2 m and complex gravel fracturing. Analysis of the faulted strata and radiocarbon ages of event horizons reveal evidence of at least one, possibly two coseismic events since the Holocene. The youngest of them overlaps with the 1756 AD Düren earthquake. The complex deformation pattern in the trench included a range of features such as liquefaction, rotated, and fractured clasts in the fault zone. I developed a new analysis technique based on “fractured-clasts”, which allows insight into coseismic rupture and fracture processes in unconsolidated gravel deposits. Results of this paleoseismic study show that faults in the Lower Rhine Graben do not move dominantly by aseismic creep. They further support the observation that faults in low-strain intraplate rifts can produce large surface-breaking earthquakes. The results of this thesis further imply that specific patterns of fractured clasts in fault zones may be a detector of coseismic rupture, and could in principle be used to calculate the energy involved in the rupture process.In der Erdbebengeologie stellt die Identifizierung und Charakterisierung von seismogenen Strukturen in Intraplattenregionen mit niedrigen Deformationsraten eine große Herausforderung dar. Die stark variable, räumliche und zeitliche Verteilung von großen Erdbeben sowie kaum mit geodätischen Messmethoden erfassbare Verformungsraten erschweren das Verständnis von Intraplattenbeben. In dicht besiedelten, humiden Gebieten sind potenziell aktive Störungen noch schwerer zu erkennen, da diese, durch Hangprozesse und anthropogene Überprägung, intensiven Veränderungen unterworfen sind. Die Niederrheinische Bucht, das nordwestliche Segment des Europäischen Känozoischen Graben Systems, ist ein erstklassiges Beispiel für ein seismisch aktives Intraplattenrift in einem humiden und dicht besiedelten Gebiet. Obwohl die Lokationen potenziell aktiver Störungen bekannt sind, ist die Kenntnis bezüglich der Rekurrenzintervalle von großen Erdbeben sowie der Art der Störungsbewegungen nach wie vor rudimentär. Die derzeitige Debatte reicht von Störungsbewegungen durch starke Erdbeben, bis hin zu aseismischem Kriechen. Ziel dieser Arbeit ist es zu klären, ob der Niederrheingraben eine Ausnahme in Bezug auf das grundsätzlich beobachtete Deformationsverhalten der oberen Kruste darstellt, wo aktive Störungen durch sprödes Bruchverhalten charakterisiert sind. Hierbei befasst sich die Studie mit der Holozänen, historischen und heutigen tektonischen Aktivität des Niederrheingrabens und legt den Fokus auf die Erforschung koseismischer Prägung der Geologie sowie der Oberflächenexpression potenziell aktiver Störungen. Es wurden hochauflösende LiDAR-Geländemodelle an Segmenten der Erft- und Wissersheimer Störung in der zentralen Niederrheinischen Bucht untersucht, um das Erhaltungspotenzial aktiver Störungen in besiedelten, humiden Gebieten zu charakerisieren. Die Ergebnisse der LiDAR-Analyse offenbaren, dass seismogene Strukturen im zentralen Teil des Niederrheingrabens starker Degradation und Modifikation unterworfen sind. Hauptursachen hierfür sind fluviatile Erosion, Hangprozesse, sowie anthropogene Überprägung. In dieser Analyse konnte zudem erstmals die Schwere der Oberflächenveränderung in der Region, ausgelöst durch Fliegerbomben aus dem Zweiten Weltkrieg, dargestellt werden. In einer groß angelegten Schürfgrabenanalyse in Holozänen Sedimenten an der Schafbergstörung, wurde eine breite Deformationszone, die eine auffallend große Anzahl zerbrochener Klasten enthielt, freigelegt. Insbesondere ist es wichtig zu klären, ob diese Störung während des Dürener Bebens von 1756 AD gebrochen ist. Die Ergebnisse der Schürfgrabenanalysen an der Schafbergstörung liefern den ersten Beweis dafür, dass Erdbeben im Niederrheingraben in historischer Zeit die Oberfläche gebrochen haben. An diesem Störungssegment äußert sich die koseismische Deformation durch einen Gesamtversatz von 1 ± 0.2 m und komplexem verbreitetem Brechen von Klasten. Die Analyse mit-verworfener Schichten sowie Radiokarbondatierungen von Ereignishorizonten beweisen mindestens ein, möglicherweise zwei Holozäne koseismische Ereignisse. Das Jüngste der Beiden deckt sich hierbei mit dem Dürener Beben von 1756 AD. In der im Schürfgraben freigelegten Störungszone wurden komplexe Deformationsmuster wie Liquefaktion sowie rotierte und gebrochene Klasten dokumentiert. Basierend auf den gebrochenen Klasten habe ich in meiner Arbeit eine neue Analysetechnik entwickelt, die es ermöglicht, detaillierte Einblicke in koseismische Bruchprozesse in unverfestigten Geröllen zu erhalten. Die Ergebnisse dieser paläoseismologischen Studie weisen darauf hin, dass Störungen im Niederrheingraben nicht aseismisch kriechen. Darüber hinaus festigen sie die Beobachtung, dass Störungen in Intraplattenrifts mit niedrigen Deformationsraten, in der Lage sind, große Erdbeben mit Oberflächenruptur zu erzeugen. Die Daten dieser Studie zeigen des Weiteren, dass spezifische Muster gebrochener Klasten in Störungszonen ein möglicher Detektor koseismischer Rupturen sein können und demzufolge zur Energieberechnung des Rupturprozesses genutzt werden können

Multi armed bandits and quantum channel oracles

Multi armed bandits are one of the theoretical pillars of reinforcement learning. Recently, the investigation of quantum algorithms for multi armed bandit problems was started, and it was found that a quadratic speed-up is possible when the arms and the randomness of the rewards of the arms can be queried in superposition. Here we introduce further bandit models where we only have limited access to the randomness of the rewards, but we can still query the arms in superposition. We show that this impedes any speed-up of quantum algorithms.Comment: 44 page

The climate in climate economics

To analyze climate change mitigation strategies, economists rely on simplified climate models - climate emulators. We propose a generic and transparent calibration and evaluation strategy for these climate emulators that is based on Coupled Model Intercomparison Project, Phase 5 (CMIP5). We demonstrate that the appropriate choice of the free model parameters can be of key relevance for the predicted social cost of carbon. We propose to use four different test cases: two tests to separately calibrate and evaluate the carbon cycle and temperature response, a test to quantify the transient climate response, and a final test to evaluate the performance for scenarios close to those arising from economic models. We re-calibrate the climate part of the widely used DICE-2016: the multi-model mean as well as extreme, but still permissible climate sensitivities and carbon cycle responses. We demonstrate that the functional form of the climate emulator of the DICE-2016 model is fit for purpose, despite its simplicity, but its carbon cycle and temperature equations are miscalibrated. We examine the importance of the calibration for the social cost of carbon in the context of a partial equilibrium setting where interest rates are exogenous, as well as the simple general equilibrium setting from DICE-2016. We find that the model uncertainty from different consistent calibrations of the climate system can change the social cost of carbon by a factor of four if one assumes a quadratic damage function. When calibrated to the multi-model mean, our model predicts similar values for the social cost of carbon as the original DICE-2016, but with a strongly reduced sensitivity to the discount rate and about one degree less long-term warming. The social cost of carbon in DICE-2016 is oversensitive to the discount rate, leading to extreme comparative statics responses to changes in preferences

ROBUST PRODUCT DESIGN – INFLUENCING FACTORS ON UPGRADEABLE MODULAR PRODUCTS

In today\u27s VUCA-World it is necessary to consider future requirements to develop change- and future-robust future products, especially regarding the increasing demand for sustainable solutions. In order to address this situation, upgradeability of modular products can be a solution. Considering that elements of modular products are used in several different products and over a long period of time, there is a need to act on this challenge. To uncover areas with a need for action, a systematic literature review on upgradeable and modular products was conducted. After resolving four fields of action and under consideration of the need for sustainable products, another systematic literature review examined the solution space of upgradable modular product architecture. In conclusion, several influencing factors on the upgradeable design of modular products could be identified, which are presented in this work

Towards an understanding of third-order galaxy-galaxy lensing

Third-order galaxy-galaxy lensing (G3L) is a next generation galaxy-galaxy lensing technique that either measures the excess shear about lens pairs or the excess shear-shear correlations about lenses. It is clear that these statistics assess the three-point correlations between galaxy positions and projected matter density. For future applications of these novel statistics, we aim at a more intuitive understanding of G3L to isolate the main features that possibly can be measured. We construct a toy model ("isolated lens model"; ILM) for the distribution of galaxies and associated matter to determine the measured quantities of the two G3L correlation functions and traditional galaxy-galaxy lensing (GGL) in a simplified context. The ILM presumes single lens galaxies to be embedded inside arbitrary matter haloes that, however, are statistically independent ("isolated") from any other halo or lens position. In the ILM, the average mass-to-galaxy number ratio of clusters of any size cannot change. GGL and galaxy clustering alone cannot distinguish an ILM from any more complex scenario. The lens-lens-shear correlator in combination with second-order statistics enables us to detect deviations from a ILM, though. This can be quantified by a difference signal defined in the paper. We demonstrate with the ILM that this correlator picks up the excess matter distribution about galaxy pairs inside clusters. The lens-shear-shear correlator is sensitive to variations among matter haloes. In principle, it could be devised to constrain the ellipticities of haloes, without the need for luminous tracers, or maybe even random halo substructure. [Abridged]Comment: 14 pages, 3 figures, 1 table, accepted by A&A; some "lens-shear-shear" were falsely "lens-lens-shear

Effects of training and motivation on auditory P300 brain–computer interface performance

Objectives Brain–computer interface (BCI) technology aims at helping end-users with severe motor paralysis to communicate with their environment without using the natural output pathways of the brain. For end-users in complete paralysis, loss of gaze control may necessitate non-visual BCI systems. The present study investigated the effect of training on performance with an auditory P300 multi-class speller paradigm. For half of the participants, spatial cues were added to the auditory stimuli to see whether performance can be further optimized. The influence of motivation, mood and workload on performance and P300 component was also examined. Methods In five sessions, 16 healthy participants were instructed to spell several words by attending to animal sounds representing the rows and columns of a 5 × 5 letter matrix. Results 81% of the participants achieved an average online accuracy of ≥70%. From the first to the fifth session information transfer rates increased from 3.72 bits/min to 5.63 bits/min. Motivation significantly influenced P300 amplitude and online ITR. No significant facilitative effect of spatial cues on performance was observed. Conclusions Training improves performance in an auditory BCI paradigm. Motivation influences performance and P300 amplitude. Significance The described auditory BCI system may help end-users to communicate independently of gaze control with their environment

Using Multiparametric Cardiac Magnetic Resonance to Phenotype and Differentiate Biopsy-Proven Chronic from Healed Myocarditis and Dilated Cardiomyopathy.

(1) Objectives: To discriminate biopsy-proven myocarditis (chronic vs. healed myocarditis) and to differentiate from dilated cardiomyopathy (DCM) using cardiac magnetic resonance (CMR). (2) Methods: A total of 259 consecutive patients (age 51 ± 15 years; 28% female) who underwent both endomyocardial biopsy (EMB) and CMR in the years 2008-2021 were evaluated. According to right-ventricular EMB results, patients were divided into either chronic (n = 130, 50%) or healed lymphocytic myocarditis (n = 60, 23%) or DCM (n = 69, 27%). The CMR protocol included functional, strain, and late gadolinium enhancement (LGE) imaging, T2w imaging, and T2 mapping. (3) Results: Left-ventricular ejection fraction (LV-EF) was higher, and the indexed end-diastolic volume (EDV) was lower in myocarditis patients (chronic: 42%, median 96 mL/m²; healed: 49%, 86 mL/m²) compared to the DCM patients (31%, 120 mL/m²), p < 0.0001. Strain analysis demonstrated lower contractility in DCM patients vs. myocarditis patients, p < 0.0001. Myocarditis patients demonstrated a higher LGE prevalence (68% chronic; 59% healed) than the DCM patients (45%), p = 0.01. Chronic myocarditis patients showed a higher myocardial edema prevalence and ratio (59%, median 1.3) than healed myocarditis (23%, 1.3) and DCM patients (13%, 1.0), p < 0.0001. T2 mapping revealed elevated values more frequently in chronic (90%) than in healed (21%) myocarditis and DCM (23%), p < 0.0001. T2 mapping yielded an AUC of 0.89 (sensitivity 90%, specificity 76%) in the discrimination of chronic from healed myocarditis and an AUC of 0.92 (sensitivity 86%, specificity 91%) in the discrimination of chronic myocarditis from DCM, both p < 0.0001. (4) Conclusions: Multiparametric CMR imaging, including functional parameters, LGE and T2 mapping, may allow differentiation of chronic from healed myocarditis and DCM and therefore help to optimize patient management in this clinical setting

Decoherence produces coherent states: an explicit proof for harmonic chains

We study the behavior of infinite systems of coupled harmonic oscillators as t->infinity, and generalize the Central Limit Theorem (CLT) to show that their reduced Wigner distributions become Gaussian under quite general conditions. This shows that generalized coherent states tend to be produced naturally. A sufficient condition for this to happen is shown to be that the spectral function is analytic and nonlinear. For a rectangular lattice of coupled oscillators, the nonlinearity requirement means that waves must be dispersive, so that localized wave-packets become suppressed. Virtually all harmonic heat-bath models in the literature satisfy this constraint, and we have good reason to believe that coherent states and their generalizations are not merely a useful analytical tool, but that nature is indeed full of them. Standard proofs of the CLT rely heavily on the fact that probability densities are non-negative. Although the CLT generally fails if the probability densities are allowed to take negative values, we show that a CLT does indeed hold for a special class of such functions. We find that, intriguingly, nature has arranged things so that all Wigner functions belong to this class.Comment: Final published version. 17 pages, Plain TeX, no figures. Online at http://astro.berkeley.edu/~max/gaussians.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/gaussians.html (faster from Europe) or from [email protected]

Comparison of eye tracking, electrooculography and an auditory brain-computer interface for binary communication: a case study with a participant in the locked-in state

Background In this study, we evaluated electrooculography (EOG), an eye tracker and an auditory brain-computer interface (BCI) as access methods to augmentative and alternative communication (AAC). The participant of the study has been in the locked-in state (LIS) for 6 years due to amyotrophic lateral sclerosis. He was able to communicate with slow residual eye movements, but had no means of partner independent communication. We discuss the usability of all tested access methods and the prospects of using BCIs as an assistive technology. Methods Within four days, we tested whether EOG, eye tracking and a BCI would allow the participant in LIS to make simple selections. We optimized the parameters in an iterative procedure for all systems. Results The participant was able to gain control over all three systems. Nonetheless, due to the level of proficiency previously achieved with his low-tech AAC method, he did not consider using any of the tested systems as an additional communication channel. However, he would consider using the BCI once control over his eye muscles would no longer be possible. He rated the ease of use of the BCI as the highest among the tested systems, because no precise eye movements were required; but also as the most tiring, due to the high level of attention needed to operate the BCI. Conclusions In this case study, the partner based communication was possible due to the good care provided and the proficiency achieved by the interlocutors. To ease the transition from a low-tech AAC method to a BCI once control over all muscles is lost, it must be simple to operate. For persons, who rely on AAC and are affected by a progressive neuromuscular disease, we argue that a complementary approach, combining BCIs and standard assistive technology, can prove valuable to achieve partner independent communication and ease the transition to a purely BCI based approach. Finally, we provide further evidence for the importance of a user-centered approach in the design of new assistive devices