Modulation equations near the Eckhaus boundary: the KdV equation

We are interested in the description of small modulations in time and space of wave-train solutions to the complex Ginzburg-Landau equation \begin{align*} \partial_T \Psi = (1+ i \alpha) \partial_X^2 \Psi + \Psi - (1+i \beta ) \Psi |\Psi|^2, \end{align*} near the Eckhaus boundary, that is, when the wave train is near the threshold of its first instability. Depending on the parameters $\alpha$, $\beta$ a number of modulation equations can be derived, such as the KdV equation, the Cahn-Hilliard equation, and a family of Ginzburg-Landau based amplitude equations. Here we establish error estimates showing that the KdV approximation makes correct predictions in a certain parameter regime. Our proof is based on energy estimates and exploits the conservation law structure of the critical mode. In order to improve linear damping we work in spaces of analytic functions.Comment: 44 pages, 8 figure

Impact of atmospheric turbulence on geodetic very long baseline interferometry

We assess the impact of atmospheric turbulence on geodetic very long baseline interferometry (VLBI) through simulations of atmospheric delays. VLBI observations are simulated for the two best existing VLBI data sets: The continuous VLBI campaigns CONT05 and CONT08. We test different methods to determine the magnitude of the turbulence above each VLBI station, i.e., the refractive index structure constant C-n(2). The results from the analysis of the simulated data and the actually observed VLBI data are compared. We find that atmospheric turbulence today is the largest error source for geodetic VLBI. Accurate modeling of atmospheric turbulence is necessary to reach the highest accuracy with geodetic VLBI

Decarbonizing Transport in the European Union: Emission Performance Standards and the Perspectives for a European Green Deal

The transport sector is a major driver of climate change both globally and in the European Union (EU). While the EU as a whole is showing declining carbon emissions, transport-related emissions are higher than in 1990. Car traffic is responsible for around 12 percent of the EU’s total greenhouse gas emissions. EU Commission President Ursula von der Leyen underlined the efforts to strengthen the decarbonization of the EU at the end of 2019 by publishing the European Green Deal (EGD) communication. In this paper, we analyze the controversy surrounding the emission performance standards for cars adopted in spring 2019. Car manufacturers must reduce the average carbon emissions of their fleets by 37.5% between 2021 and 2030. In this respect, the new emission performance standards are more ambitious than the previous ones. However, our argument is that without a major shift in the balance of power, extensive decarbonization and a departure from car-centered transport development will not be possible. Therefore, it is crucial for mobility research to critically engage with lobbying power in the EU and with concepts such as environmental leadership, which often underexpose the structural power of incumbent actors and existing path dependencies

Greening the Car? Conflict Dynamics within the German Platform for Electric Mobility

The environmental crisis due to air pollution, high CO2 emissions, noise from traffic and soil ceiling requires profound changes to the car-dependent transport system. This article examines the political dynamics of German transport politics, focusing on the National Platform for Electric Mobility (NPE), a high-level political forum that aimed to accelerate the run-up of the electric mobility market in Germany. The NPE provides an interesting case to study the strategies of stakeholders in influencing policy-making and shaping alternative pathways to the car-centered transport system. The paper focusses on actor constellations and the conflicts that arise within the NPE, as well as the temporal dynamics within the electric mobility debate. The findings suggest that the NPE contributed to a narrow understanding of mobility transformation based on road transport and electric cars, but that it is better described as ecological modernization. Within this narrow framework, a fundamental conflict unfolds between strong advocates versus those slowing down the ecological modernization of the car. A third group demands at least a partial departure from the automobile-centered model but remains marginalized within the NPE. Aside from this core conflict, members of the NPE struggled over the location for battery cell production, the introduction of a purchase grant known as the environmental bonus, and the expansion of battery recharging infrastructure. These issues illustrate that discussions within the NPE relate to the political debates about the future of mobility, which have intensified in Germany in recent years. However, the case of the NPE shows that high-level stakeholder platforms are not an adequate forum to legitimately deliberate and to practically contribute to a wider and more fundamental rethink of future mobility concepts. View Full-Tex

Fidelity approach to the disordered quantum XY model

We study the random XY spin chain in a transverse field by analyzing the susceptibility of the ground state fidelity, numerically evaluated through a standard mapping of the model onto quasi-free fermions. It is found that the fidelity susceptibility and its scaling properties provide useful information about the phase diagram. In particular it is possible to determine the Ising critical line and the Griffiths phase regions, in agreement with previous analytical and numerical results.Comment: 4 pages, 3 figures; references adde

Assessment of Physical Activity Patterns in Adolescent Patients With Anorexia Nervosa and Their Effect on Weight Gain

(1) Background: Altered physical activity (PA) affects weight recovery in anorexia nervosa (AN) patients. The study aimed to objectively characterize PA patterns and their effect on weight trajectory in adolescent AN patients. (2) Methods: PA was assessed in 47 patients on admission to inpatient treatment, in n = 25 of these patients again 4 weeks after discharge (follow-up, FU), as well as in 20 adolescent healthy controls using the Sense Wear™ armband. The following PA categories were defined by metabolic equivalent (MET) ranges: sedentary behavior (SB), light (LPA), moderate (MPA), vigorous (VPA), and high-level PA (HLPA= MPA + VPA). (3) Results: LPA on admission was significantly higher in AN patients than in controls (103 vs. 55 min/d, p < 0.001), and LPA in AN decreased over time to 90 min/d (p = 0.006). Patients with higher admission LPA (n = 12) still had elevated LPA at FU (p = 0.003). High admission LPA was associated with a higher inpatient BMI percentage gain (ΔBMI%; 18.2% ± 10.0% vs. 12.0% ± 9.7%, p = 0.037) but with a loss of ΔBMI% at FU (-2.3% ± 3.6% vs. 0.8% ± 3.6%, p = 0.045). HLPA at baseline was associated with a lower inpatient ΔBMI% (p = 0.045). (4) Conclusion: Elevated LPA in AN patients decreased after inpatient treatment, and PA patterns had an impact on weight trajectory

Event Indexing Systems for Efficient Selection and Analysis of HERA Data

The design and implementation of two software systems introduced to improve the efficiency of offline analysis of event data taken with the ZEUS Detector at the HERA electron-proton collider at DESY are presented. Two different approaches were made, one using a set of event directories and the other using a tag database based on a commercial object-oriented database management system. These are described and compared. Both systems provide quick direct access to individual collision events in a sequential data store of several terabytes, and they both considerably improve the event analysis efficiency. In particular the tag database provides a very flexible selection mechanism and can dramatically reduce the computing time needed to extract small subsamples from the total event sample. Gains as large as a factor 20 have been obtained.Comment: Accepted for publication in Computer Physics Communication

Short-baseline interferometry local-tie experiments at the Onsala Space Observatory

We present results from observation, correlation and analysis of interferometric measurements between the three geodetic very long baseline interferometry (VLBI) stations at the Onsala Space Observatory. In total, 25 sessions were observed in 2019 and 2020, most of them 24 h long, all using X band only. These involved the legacy VLBI station ONSALA60 and the Onsala twin telescopes, ONSA13NE and ONSA13SW, two broadband stations for the next-generation geodetic VLBI global observing system (VGOS). We used two analysis packages: nu Solve to pre-process the data and solve ambiguities, and ASCOT to solve for station positions, including modelling gravitational deformation of the radio telescopes and other significant effects. We obtained weighted root mean square post-fit residuals for each session on the order of 10-15 ps using group-delays and 2-5 ps using phase-delays. The best performance was achieved on the (rather short) baseline between the VGOS stations. As the main result of this work, we determined the coordinates of the Onsala twin telescopes in VTRF2020b with sub-millimetre precision. This new set of coordinates should be used from now on for scheduling, correlation, as a priori for data analyses, and for comparison with classical local-tie techniques. Finally, we find that positions estimated from phase-delays are offset similar to+3 mm in the up-component with respect to group-delays. Additional modelling of (elevation dependent) effects may contribute to the future understanding of this offset