Influence of the magnetic field on the transmission characteristics and the neutrino mass systematic of the KATRIN experiment

The thesis at hand has successfully investigated and characterized the extended magnet system of the KATRIN experiment and implemented a detailed simulation model to take into account all field contributions. A concise modeling and understanding of the magnetic field close to the analyzing plane is crucial for a precise measurement and analysis of the neutrino mass with a sensitivity of 200 meV (90 % C.L.). A key aspect of the work performed here is that the contributions of individual magnets to the field in the analyzing plane in the spectrometer have been identified for various configurations. Based on these measurements, the previously undetermined remaining magnetic background field could be quantified. The advanced magnetic field model of this thesis allows to significantly reduce previously unexplained field deviations, verified by an in-depth analysis of extensive transmission function measurements with an electron gun, offering a sharp energy distribution and small angular spread. Of key importance thereby was a precise reconstruction of the emitted electrons of the electron gun in Monte Carlo simulations and the implementation of a realistic electron spectrum of the electron gun in the analysis framework. When all magnetic field contributions are taken into account, the transmission properties of the spectrometer can be determined with an accuracy level which is improved by a factor 3 in comparison to previous analyses. Correspondingly, the magnetic field there is determined to an unprecedented accuracy with a deviation between measurement and simulation of (3 ± 11) μT when a field of 363 μT is applied. Finally, the influence of identified magnetic field deviations on the neutrino mass sensitivity of the KATRIN experiment is studied by means of extensive ensemble tests. From this, an upper limit on the magnetic field of 585 μT in the KATRIN spectrometer is deduced to restrict the additional contribution to the systematic uncertainty budget to a level of 1 % for an optimal measurement of the neutrino mass

Kassiopeia: A Modern, Extensible C++ Particle Tracking Package

The Kassiopeia particle tracking framework is an object-oriented software package using modern C++ techniques, written originally to meet the needs of the KATRIN collaboration. Kassiopeia features a new algorithmic paradigm for particle tracking simulations which targets experiments containing complex geometries and electromagnetic fields, with high priority put on calculation efficiency, customizability, extensibility, and ease of use for novice programmers. To solve Kassiopeia's target physics problem the software is capable of simulating particle trajectories governed by arbitrarily complex differential equations of motion, continuous physics processes that may in part be modeled as terms perturbing that equation of motion, stochastic processes that occur in flight such as bulk scattering and decay, and stochastic surface processes occuring at interfaces, including transmission and reflection effects. This entire set of computations takes place against the backdrop of a rich geometry package which serves a variety of roles, including initialization of electromagnetic field simulations and the support of state-dependent algorithm-swapping and behavioral changes as a particle's state evolves. Thanks to the very general approach taken by Kassiopeia it can be used by other experiments facing similar challenges when calculating particle trajectories in electromagnetic fields. It is publicly available at https://github.com/KATRIN-Experiment/Kassiopei

PREDICT identifies precipitating events associated with the clinical course of acutely decompensated cirrhosis

Background & Aims: Acute decompensation (AD) of cirrhosis may present without acute-on-chronic liver failure (ACLF) (ADNo ACLF), or with ACLF (AD-ACLF), defined by organ failure(s). Herein, we aimed to analyze and characterize the precipitants leading to both of these AD phenotypes. Methods: The multicenter, prospective, observational PREDICT study (NCT03056612) included 1,273 non-electively hospitalized patients with AD (No ACLF = 1,071; ACLF = 202). Medical history, clinical data and laboratory data were collected at enrolment and during 90-day follow-up, with particular attention given to the following characteristics of precipitants: induction of organ dysfunction or failure, systemic inflammation, chronology, intensity, and relationship to outcome. Results: Among various clinical events, 4 distinct events were precipitants consistently related to AD: proven bacterial infections, severe alcoholic hepatitis, gastrointestinal bleeding with shock and toxic encephalopathy. Among patients with precipitants in the AD-No ACLF cohort and the AD-ACLF cohort (38% and 71%, respectively), almost all (96% and 97%, respectively) showed proven bacterial infection and severe alcoholic hepatitis, either alone or in combination with other events. Survival was similar in patients with proven bacterial infections or severe alcoholic hepatitis in both AD phenotypes. The number of precipitants was associated with significantly increased 90day mortality and was paralleled by increasing levels of surrogates for systemic inflammation. Importantly, adequate first-line antibiotic treatment of proven bacterial infections was associated with a lower ACLF development rate and lower 90-day mortality. Conclusions: This study identified precipitants that are significantly associated with a distinct clinical course and prognosis in patients with AD. Specific preventive and therapeutic strategies targeting these events may improve outcomes in patients with decompensated cirrhosis. Lay summary: Acute decompensation (AD) of cirrhosis is characterized by a rapid deterioration in patient health. Herein, we aimed to analyze the precipitating events that cause AD in patients with cirrhosis. Proven bacterial infections and severe alcoholic hepatitis, either alone or in combination, accounted for almost all (96-97%) cases of AD and acute-on-chronic liver failure. Whilst the type of precipitant was not associated with mortality, the number of precipitant(s) was. This study identified precipitants that are significantly associated with a distinct clinical course and prognosis of patients with AD. Specific preventive and therapeutic strategies targeting these events may improve patient outcomes. (c) 2020 European Association for the Study of the Liver. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Warping NMPC for online generation and tracking of optimal trajectories

Generation of feasible and optimal reference trajectories is crucial in tracking Nonlinear Model Predictive Control. Especially, for stability and optimality in presence of a time varying parameter, adaptation of the tracking trajectory has to be implemented. General approaches are real-time generation of trajectories or switching between a discrete set of precomputed trajectories. In order to circumvent the operational efforts of these methods for a special type of dynamical systems, we propose time warping as an alternative approach. This algorithm implements online generation of tracking trajectories by warping a single precomputed reference. In detail, warpable systems, feasibility and optimality of trajectories and the controller implementation are discussed. Finally, as an application example, simulation results of a tethered kite system for airborne wind energy generation are presented.Team DeSchutte

Warping model predictive control for application in control of a real airborne wind energy system

Fast online generation of feasible and optimal reference trajectories is crucial in tracking model predictive control, especially for stability and optimality in presence of a time varying parameter. In this paper, in order to circumvent the operational efforts of handling a discrete set of precomputed trajectories and switching between them, time warping of a single trajectory is proposed as an alternative concept. In particular, the conceptual ideas of warping theory are presented and illustrated based on the example of a tethered kite system for airborne wind energy. In detail, for warpable systems, feasibility and optimality of trajectories are discussed. Subsequently, the full algorithm of a nonlinear model predictive control implementation based on warping a single precomputed reference is presented. Finally, the warping algorithm is applied to the airborne wind energy system. Simulation results in presence of real world perturbations are evaluated and compared.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Hybrid, Adaptive and Nonlinea

Which synthesis?: strategies of theoretical integration and the neorealist-neoliberal debate

Despite growing interest in the promises and problems of theoretical synthesis among political scientists, frameworks for assessing the potential advantages of different pathways to theoretical integration are scarce. We build on the conceptualization of alternative strategies for synthesis proposed by Jupille, Caporaso, and Checkel and assess the implications of two criteria — parsimony and empirical fit — for understanding the relationship between two influential strands of international relations theory, neorealism and neoliberalism. Neorealists present concerns about relative gains as evidence of the limited scope of the neoliberal theory of international cooperation. We argue that, on the contrary, neoliberalism provides theoretical tools that are indispensable to determine when and why relative-gains concerns thwart international cooperation, and that this provides a strong case for subsuming neorealism under neoliberalism in a parsimonious synthesis. We apply this framework to explain an empirical puzzle: why two arch-rival states — Austria and Prussia in the second half of the 18th century — succeeded in cooperating in some cases but failed in others