Locations of Auroral Kilometric Radiation Bursts Inferred From Multi-Spacecraft Wideband Cluster VLBI Observations i: Description of Technique and Initial Results

The Cluster Wideband Data instrument has been used to determine the locations of auroral kilometric radiation (AKR) using very long baseline interferometry. The technique involves cross-correlating individual AKR bursts from all six Cluster baselines using time and frequency filtered waveforms. We report the locations of over 1,700 individual AKR bursts during six observing epochs between 10 July 2002 and 22 January 2003 when the Cluster constellation was high above the southern or northern hemisphere. In general we find that the AKR burst locations lie along magnetic field lines which map onto the nighttime auroral zone as expected from previous AKR studies. The distribution of AKR auroral footprint locations at each epoch had a overall spatial scale between 1000 - 2000 km, much larger than the positional uncertainty of an individual AKR burst location magnetic footprint, but a small fraction of the auroral oval. For two of the six epochs, there was a significant drift in the mean location of AKR activity over a period of 1-2 hours. The drift was predominantly in latitude at one epoch and in longitude at the other, with average drift speed V ~ 80-90 m s-1 at the AKR emission location.Comment: 31 pages, 9 figures, accepted for publication 19 June 2003 in JGR Space Physics. accepted for publicatio

Use of digital healthcare solutions for care delivery during a pandemic-chances and (cyber) risks referring to the example of the COVID-19 pandemic

During pandemics, regular service provisioning processes in medical care may be disrupted. Digital health promises many opportunities for service provisioning during a pandemic. However, a broad penetration of medical processes with information technology also has drawbacks. Within this work, the authors use the COVID-19 pandemic to analyze the chances and the risks that may come with using digital health solutions for medical care during a pandemic. Therefore, a multi-methods approach is used. First we use a systematic literature review for reviewing the state of the art of digital health applications in healthcare. Furthermore, the usage of digital health applications is mapped to the different processes in care delivery. Here we provide an exemplary process model of oncological care delivery. The analysis shows that including digital health solutions may be helpful for care delivery in most processes of medical care provisioning. However, research on digital health solutions focuses strongly on some few processes and specific disciplines while other processes and medical disciplines are underrepresented in literature. Last, we highlight the necessity of a comprehensive risk-related debate around the effects that come with the use of digital healthcare solutions

Motivation-based Attacker Modelling for Cyber Risk Management: A Quantitative Content Analysis and a Natural Experiment

Cyber-attacks have a tremendous impact on worldwide economic performance. Hence, it is vitally important to implement effective risk management for different cyber-attacks, which calls for profound attacker models. However, cyber risk modelling based on attacker models seems to be restricted to overly simplified models. This hinders the understanding of cyber risks and represents a heavy burden for efficient cyber risk management. This work aims to forward scientific research in this field by employing a multi-method approach based on a quantitative content analysis of scientific literature and a natural experiment. Our work gives evidence for the oversimplified modelling of attacker motivational patterns. The quantitative content analysis gives evidence for a broad and established misunderstanding of attackers as being illicitly malicious. The results of the natural ex- periment substantiate the findings of the content analysis. We thereby contribute to the improvement of attacker modelling, which can be considered a necessary prerequisite for effective cyber risk management

Breathing mode for systems of interacting particles

We study the breathing mode in systems of trapped interacting particles. Our approach, based on a dynamical ansatz in the first equation of the Bogolyubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy allows us to tackle at once a wide range of power law interactions and interaction strengths, at linear and non linear levels. This both puts in a common framework various results scattered in the literature, and by widely generalizing these, emphasizes universal characters of this breathing mode. Our findings are supported by direct numerical simulations.Comment: 4 pages, 4 figure

Identifizierung von Interaktionspartnern des Transkriptionsfaktors TRPS1

Das TRPS1 Gen kodiert für einen Transkriptionsrepressor. Mutationen oder eine Deletion dieses Gens verursachen die Tricho-Rhino-Phalangealen Syndrome. Die hier vorliegende Arbeit beschreibt Analysen zur Charakterisierung des TRPS1 Proteins. Durch in vitro Rekonstruktionen spezifischer in Patienten mit TRPS identifizierten Mutationen, konnte nur ein von ursprünglich zwei vorhergesagten Kernlokalisierungssignalen als funktionell klassifiziert werden. Der Schwerpunkt dieser Arbeit lag in der Identifizierung von TRPS1-Bindeproteinen. Durch die Verwendung von zwei überlappenden Trps1 Fragmenten konnten in einem Hefe Zwei-Hydrid System sieben potentielle Interaktionspartner gefunden werden. Der Einsatz unterschiedlicher Trps1 Fragmente in weiteren Hefe und biochemischen Systemen ermöglichte eine Eingrenzung der für diese Interaktionen erforderlichen Regionen auf unterschiedliche Bereiche innerhalb des Trps1 Proteins. In sich anschließenden immunchemischen Co-Präzipitierungen und Co-Lokalisierungsstudien konnten die Interaktionen der humanen Orthologe TRPS1 zu LC8a, RNF4 und TOPORS verifiziert werden. Mobilitätsshift Experimente zeigten, dass sowohl LC8a als auch RNF4 das Bindeverhalten von TRPS1 zur GATA-Konsensus-Sequenz verändern. Untersuchungen dieser Interaktionen in einem Luciferase-Reporter System ergaben, dass LC8a und RNF4 zu einer Reduktion bzw. Inhibition der TRPS1-vermittelten Repression in der GATA-abhängigen Transkription führten. Die SUMO-E3-Ligase TOPORS zeigte dagegen keinen signifikanten Einfluss auf die transkriptionelle Funktion von TRPS1. Durch die Verwendung eines ? SUMO Antikörpers in Western-Blot Analysen konnte eine mögliche SUMOylierung von TRPS1 gezeigt werden. Untersuchungen zur intrazellulären Verteilung zeigten das endogene TRPS1 in zwei distinkten subnukleären Strukturen. Durch TRPS1+PML Co-Lokaliserungsstudien konnte ein geringer Teil des endogenen TRPS1 innerhalb der PML-Kernkörperchen nachgewiesen werden, wobei die Charakterisierung der durch den größeren Anteil an TRPS1 gebildeten Strukturen noch aussteht. Die hier vorgestellten Ergebnisse und weitere Analysen zur spezifischen subnukleären Verteilung und der noch nicht näher untersuchten TRPS1-Interaktionen, können vielleicht zum Verständnis der molekularen Mechanismen der TRP Syndrome beitragen

Spin Filter Properties of Armchair Graphene Nanoribbons with Substitutional Fe Atoms

The spin filter capability of a (0,8) armchair graphene nanoribbon with Fe atoms at substitutional sites is investigated by density functional theory in combination with the non-equilibrium Greens function technique. For specific arrangements, a high degree of spin polarization is achieved. These include a single substitution at an edge position or double substitution in the central sector of the transmission element. The possibility of switching between majority and minority spin polarization by changing the double substitution geometry is predicted. Including the bias dependence of the transmission function proves to be essential for correct representation of the spin-resolved current-voltage profiles

Method for fabricating semiconductor devices

A process for fabricating gold/gallium arsenide structures, in situ, on molecular beam epitaxially grown gallium arsenide. The resulting interface proves to be Ohmic, an unexpected result which is interpreted in terms of increased electrode interdiffusion. More importantly, the present invention surprisingly permits the fabrication of Ohmic contacts in a III-V semiconductor material at room temperature. Although it may be desireable to heat the Ohmic contact to a temperature of, for example, 200 degrees Centigrade if one wishes to further decrease the resistance of the contact, such low temperature annealing is much less likely to have any deleterious affect on the underlying substrate. The use of the term in situ herein, contemplates continuously maintaining an ultra-high vacuum, that is a vacuum which is at least 10.sup.-8 Torr, until after the metallization has been completed. An alternative embodiment of the present invention comprising an additional step, namely the termination of the gallium arsenide by a two monolayer thickness of epitaxial aluminum arsenide as a diffusion barrier, enables the recovery of Schottky barrier behavior, namely a rectified I-V characteristic. The present invention provides a significant breakthrough in the fabrication of III-V semiconductor devices wherein excellent Ohmic contact and Schottky barrier interfaces to such devices can be achieved simply and inexpensively and without requiring the high temperature processing of the prior art and also without requiring the use of exotic high temperature refractory materials as substitutes for those preferred contact metals such as gold, aluminum and the like