Periodic orbit quantization of chaotic maps by harmonic inversion

A method for the semiclassical quantization of chaotic maps is proposed, which is based on harmonic inversion. The power of the technique is demonstrated for the baker's map as a prototype example of a chaotic map.Comment: 7 pages, 1 figure, accepted for publication in Phys. Lett.

Electronic Structure of Atoms in Magnetic Quadrupole Traps

We investigate the electronic structure and properties of atoms exposed to a magnetic quadrupole field. The spin-spatial as well as generalized time reversal symmetries are established and shown to lead to a two-fold degeneracy of the electronic states in the presence of the field. Low-lying as well as highly excited Rydberg states are computed and analyzed for a broad regime of field gradients. The delicate interplay between the Coulomb and various magnetic interactions leads to complex patterns of the spatial spin polarization of individual excited states. Electromagnetic transitions in the quadrupole field are studied in detail thereby providing the selection rules and in particular the transition wavelengths and corresponding dipole strengths. The peculiar property that the quadrupole magnetic field induces permanent electric dipole moments of the atoms is derived and discussed.Comment: 17 pages, 13 figures, accepted for publication in PR

The Hydrogen Atom in Combined Electric and Magnetic Fields with Arbitrary Mutual Orientations

For the hydrogen atom in combined magnetic and electric fields we investigate the dependence of the quantum spectra, classical dynamics, and statistical distributions of energy levels on the mutual orientation of the two external fields. Resonance energies and oscillator strengths are obtained by exact diagonalization of the Hamiltonian in a complete basis set, even far above the ionization threshold. At high excitation energies around the Stark saddle point the eigenenergies exhibit strong level repulsions when the angle between the fields is varied. The large avoided crossings occur between states with the same approximately conserved principal quantum number, n, and this intramanifold mixing of states cannot be explained, not even qualitatively, by conventional perturbation theory. However, it is well reproduced by an extended perturbation theory which takes into account all couplings between the angular momentum and Runge-Lenz vector. The large avoided crossings are interpreted as a quantum manifestation of classical intramanifold chaos. This interpretation is supported by both classical Poincar\'e surfaces of section, which reveal a mixed regular-chaotic intramanifold dynamics, and the statistical analysis of nearest-neighbor-spacingComment: two-column version, 10 pages, REVTeX, 10 figures, uuencoded, submitted to Rhys. Rev.

Atlas der Stadt- und Regionalentwicklung 2022: Unter besonderer Berücksichtigung der räumlichen Auswirkungen von COVID-19

Der Ausbruch der COVID-19-Pandemie im Jahr 2020 hat massive Einschnitte für Gesellschaft und Wirtschaft nach sich gezogen. Kontaktbeschränkungen, Schulschließungen, Homeoffice und Maskenpflicht veränderten den Alltag aller Menschen. Die Pandemie hat Gewissheiten in Frage gestellt, aber auch den Blick auf Herausforderungen in Gesellschaft, Wirtschaft und Verwaltung geschärft. Sie hat den Weg geöffnet für neue Formen der mobilen Arbeit. Sie hat Debatten um soziale Ungleichheit und unterschiedliche Bildungschancen befeuert. Die Pandemie hat gezeigt, wie staatliche Instrumente wie das Kurzarbeitergeld die Arbeitsmärkte wirksam gestützt haben. Sie hat den Blick auf die Zukunft der Innenstädte gelenkt und Impulse für die Verkehrswende gesetzt. Und sie hat deutlich gemacht, dass die Digitalisierung in allen Bereichen noch schneller vorangehen muss als bisher. Der vorliegende Atlas umreißt in Karten und Abbildungen die Entwicklungen in den Teilräumen Deutschlands und über Daten erfassbare Veränderungen zwischen 2020, dem ersten Pandemiejahr, und 2019. In Teilbereichen liegen auch schon kleinräumige Informationen für das zweite Pandemiejahr 2021 vor. Welche Veränderungen sind bereits kurzfristig zur "vorpandemischen Normalität" beobachtbar? Lassen sich die vermuteten Veränderungen überhaupt in den Kennzahlen und Entwicklungsverläufen der Regionen ablesen? Wie groß sind die regionalen Unterschiede hinsichtlich u.a. der demografischen, sozialen, Siedlungsstruktur; welche werden durch die Pandemie verstärkt? Die datengestützten Einschätzungen zum COVID-19-Effekt auf die regionalen Entwicklungen wird über Forschungsergebnisse und Literatur untermauert. In vielen Fällen wirkt sich die Pandemie beschleunigend auf Entwicklungen, die sich bereits vor der Pandemie abzeichneten

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

TAKE CoVer: EXPLOITING VERSION SUPPORT IN COOPERATIVE SYSTEMS

Current CSCW applications support one or more modes of cooperative work. The selection of and transition between these modes is usually placed on the users. At IPSI we built the SEPIA cooperative hypermedia authoring environment supporting a complete set of situations arising during collaborative work and the smooth transitions between them. While early use of the system shows the benefits of supporting smooth transitions between different collaborative modes, it also reveals some deficits regarding parallel work, management of alternative documents, or reuse of document parts. We propose to integrate version support to overcome these limitations. This leads to a versioned data management and an extended user-interface enabling concurrent users to select a certain state of their work, to be aware of related changes, and to cooperate with others either asynchronously or synchronously