Closed-orbit theory for spatial density oscillations

We briefly review a recently developed semiclassical theory for quantum oscillations in the spatial (particle and kinetic energy) densities of finite fermion systems and present some examples of its results. We then discuss the inclusion of correlations (finite temperatures, pairing correlations) in the semiclassical theory.Comment: LaTeX, 10pp., 2 figure

Apuleius

Die Schrift des Rhetors und platonischen Philosophen Apuleius von Madaura (Nordafrika, 2. Jh. n.Chr.) ist ein öffentlich gehaltener Lehrvortrag, in dem der Autor der in der Antike vielverhandelten Frage nachgeht, was das sog. Daimonion sei, auf das Sokrates sich in den Platonischen Dialogen und in den Schriften Xenophons so häufig beruft. Um diese Frage umfassend zu beantworten, entwirft Apuleius ein fast vollständiges System mittelplatonischer Theologie. Im Mittelpunkt steht dabei die Lehre von den Dämonen; denn Apuleius will nachweisen, dass das Daimonion der persönliche Dämon (Schutzgeist) des Sokrates ist. Die Schrift stellt das ausführlichste und reichste Dokument zur Lehre der Mittelplatoniker von den Dämonen dar. Als Lehrvortrag ist es zugleich ein spektakuläres Zeugnis für die Redekunst des 2. Jahrhunderts n.Chr

Closed orbits and spatial density oscillations in the circular billiard

We present a case study for the semiclassical calculation of the oscillations in the particle and kinetic-energy densities for the two-dimensional circular billiard. For this system, we can give a complete classification of all closed periodic and non-periodic orbits. We discuss their bifurcations under variation of the starting point r and derive analytical expressions for their properties such as actions, stability determinants, momentum mismatches and Morse indices. We present semiclassical calculations of the spatial density oscillations using a recently developed closed-orbit theory [Roccia J and Brack M 2008 Phys. Rev. Lett. 100 200408], employing standard uniform approximations from perturbation and bifurcation theory, and test the convergence of the closed-orbit sum.Comment: LaTeX, 42 pp., 17 figures (24 *.eps files, 1 *.tex file); final version (v3) to be published in J. Phys.

Über die Natur des Kosmos und der Seele. /

Originally presented as the author's thesis, Mainz, 1968

Enzymes Involved in Anaerobic Respiration Appear To Play a Role in Actinobacillus pleuropneumoniae Virulence

Actinobacillus pleuropneumoniae, the etiological agent of porcine pleuropneumonia, is able to survive on respiratory epithelia, in tonsils, and in the anaerobic environment of encapsulated sequesters. It was previously demonstrated that a deletion of the anaerobic dimethyl sulfoxide reductase gene (dmsA) results in attenuation in acute disease (N. Baltes, S. Kyaw, I. Hennig-Pauka, and G. F. Gerlach, Infect. Immun. 71:6784-6792, 2003). In the present study, using two-dimensional polyacrylamide gel electrophoresis and quadrupole time-of-flight mass spectrometry, we identified an aspartate ammonia-lyase (AspA) which is upregulated upon induction with bronchoalveolar lavage fluid (BALF). This enzyme is involved in the production of fumarate, an alternative electron acceptor under anaerobic conditions. The coding gene (aspA) was cloned and shown to be present in all A. pleuropneumoniae serotype reference strains. The transcriptional start point was identified downstream of a putative FNR binding motif, and BALF-dependent activation of aspA was confirmed by construction of an isogenic A. pleuropneumoniae mutant carrying a chromosomal aspA::luxAB transcriptional fusion. Two aspA deletion mutants, A. pleuropneumoniae ΔaspA and A. pleuropneumoniae ΔaspAΔdmsA, were constructed, both showing reduced growth under anaerobic conditions in vitro. Pigs challenged with either of the two mutants in an aerosol infection model showed a lower lung lesion score than that of the A. pleuropneumoniae wild-type (wt) controls. Pigs challenged with A. pleuropneumoniae ΔaspAΔdmsA had a significantly lower clinical score, and this mutant was rarely reisolated from unaltered lung tissue; in contrast, A. pleuropneumoniae ΔaspA and the A. pleuropneumoniae wt were consistently reisolated in high numbers. These results suggest that enzymes involved in anaerobic respiration are necessary for the pathogen's ability to persist on respiratory tract epithelium and play an important role in A. pleuropneumoniae pathogenesis