V751 Cyg and V Sge as transient supersoft X-ray sources

I review the observational evidence for luminous, soft X-ray emission during optical low-states in the two cataclysmic variables V751 Cyg and V Sge, and discuss the possible link to the canonical supersoft X-ray sources.Comment: 6 pages with newarcrc.sty; inv. talk given at the 60th birthday Symp. in honour of Brian Warner, Oxford, April 1999, to appear in New Astronomy Reviews (Elsevier), eds. P. Charles, A. King, D. O'Donoghue; also available from http://www.aip.de/~jcg/publis.htm

The benefit of simultaneous seven-filter imaging: 10 years of GROND observations

A variety of scientific results have been achieved over the last 10 years with the GROND simultaneous 7-channel imager at the 2.2m telescope of the Max-Planck Society at ESO/La Silla. While designed primarily for rapid observations of gamma-ray burst afterglows, the combination of simultaneous imaging in the Sloan g'r'i'z' and near-infrared JHK bands at a medium-sized (2.2m) telescope and the very flexible scheduling possibility has resulted in an extensive use for many other astrophysical research topics, from exoplanets and accreting binaries to galaxies and quasars.Comment: 26 pages, 22 figure

Cumulant ratios in fully developed turbulence

In the context of random multiplicative cascade processes, we derive analytical solutions for one- and two-point cumulants with restored translational invariance. On taking ratios of cumulants in ln epsilon, geometrical effects due to spatial averaging cancel out. These ratios can successfully distinguish between splitting functions while multifractal scaling exponents and multiplier distributions cannot.Comment: 9th Workshop on Multiparticle Production (Torino), 9 pages latex, incl 9 figs and espcrc2.st

Signatures of the quark gluon plasma: a personal overview

We first discuss, on a no-QGP basis, the two prominent indications of (a) enhanced strangeness production and of (b) anomalous $J/\psi$-suppression: We elaborate in particular on a recent idea of antihyperon production solely by multi-mesonic reactions. As a possible source for an enhanced dissociation of $c \bar{c}$ pairs we summarize the findings within the 'early'-comover absorption scenario of prehadronic string excitations. As an exotic candidate we then finally adress the stochastic formation of so called disoriented chiral condensates: An experimentally feasible DCC, if it does exist, has to be a rare event following an unusual and nontrivial distribution on an event by event basis.Comment: 10 pages, 5 figures, uses ws-p8-50x6_00.cls style file, contribution for the proceedings of `Luederitz 2000: Fundamental and Applied Aspects of Modern Physics', November 2000, Luederitz, Namibi

The Effect of Entertainment in Newspaper and Television News Coverage

In this paper, we analyze the equilibrium amount of entertainment in news coverage of newspapers and television stations. We find that a shift in the inclination to read, expressed by a shift in the (psychological) distance costs, induces both media outlets to incorporate more entertaining elements in news coverage. The introduction of commercial television, however, which leads to a unilateral fall in the distance costs to the television broadcast, yields different results. It induces a negative effect on the profits of both media outlets, and increases price competition. Furthermore, the newspaper offers less while the television channel offers more entertainment. Overall, this leads to a marginalization of informational content, as the television channel gains market shares at the expense of the newspaper

On Mirror Symmetry for Calabi-Yau Fourfolds with Three-Form Cohomology

We review the Kaluza-Klein reduction of Type IIA string theory on Calabi-Yau fourfolds and apply mirror symmetry to the resulting two-dimensional $\mathcal{N}=(2,2)$ effective theories. In the course of the reduction we focus especially on non-trivial three-form cohomology on these fourfolds and investigate the couplings of the corresponding massless zero-modes. These show a dependence on both complex structure as well as K\"ahler structure deformations and we provide evidence that they are determined by two holomorphic functions that get exchanged via mirror symmetry. Application of the mirror map enables us to give an explicit description of these functions at the large volume and large complex structure point of the moduli space.Comment: Proceedings prepared for the "Workshop on Geometry and Physics", November 2016, Ringberg Castle, Germany; 10 page

Chemical Equilibration of Antihyperons

Rapid chemical equilibration of antihyperons by means of the interplay between strong annihilation on baryons and the corresponding backreactions of multi-mesonic (fusion-type) processes in the later, hadronic stage of an ultrarelativistic heavy ion collision will be discussed. Explicit rate calculations for a dynamical setup are presented. At maximum SPS energies yields of each antihyperon specie are obtained which are consistent with chemical saturated populations of $T \approx 150-160$ MeV. The proposed picture supports dynamically the popular chemical freeze-out parameters extracted within thermal models.Comment: revised version for some typos and two references; 6 pages, 4 figures; contribution to the Int. Workshop XXX on Gross Properties of Nuclei and Nuclear Excitations: Ultrarelativistic Heavy-Ion Collisions, Hirschegg, Jan. 13 - 19, 200