Heavy Quarks in Strongly Coupled Non-Conformal Plasmas with Anisotropy

We analysis physical observables of heavy quarks in gravity models describing strongly coupled non-conformal plasmas with anisotropy via the gauge/gravity duality. The focus lies on the binding energy of static quark-antiquark $(q\bar q$-)pairs, the maximum distance (screening distance) of a bound $q\bar q$-pair and the drag force on uniformly moving quarks in the hot plasma. In order to discover universal behavior in the observables, the computations are worked out in a two parameter deformation of pure gravity in $AdS_5$ spacetime with a black brane which is assumed to be dual to a respective two parameter deformation of $\mathcal{N}$=\,4 supersymmetric Yang-Mills (SYM) theory at temperature $T$. The deformation is designed to break isotropy and conformal symmetry and is a solution to equations of motion of a gravity action.Comment: 32 pages, 14 figures, v2: references adde

Entanglement entropy through conformal interfaces in the 2D Ising model

We consider the entanglement entropy for the 2D Ising model at the conformal fixed point in the presence of interfaces. More precisely, we investigate the situation where the two subsystems are separated by a defect line that preserves conformal invariance. Using the replica trick, we compute the entanglement entropy between the two subsystems. We observe that the entropy, just like in the case without defects, shows a logarithmic scaling behavior with respect to the size of the system. Here, the prefactor of the logarithm depends on the strength of the defect encoded in the transmission coefficient. We also comment on the supersymmetric case.Comment: 27 pages, 3 figures, v2: additional references and minor correction

Constraints on the Bulk Lorentz Factor of GRB 990123

GRB 990123 was a long, complex gamma-ray burst accompanied by an extremely bright optical flash. We present the collective constraints on the bulk Lorentz factor for this burst based on estimates from burst kinematics, synchrotron spectral decay, prompt radio flash observations, and prompt emission pulse width. Combination of these constraints leads to an average bulk Lorentz factor for GRB 990123 of Gamma_0=1000 +/- 100 which implies a baryon loading of M_jet=8 (+17/-2) x 10^-8 Msolar. We find these constraints to be consistent with the speculation that the optical light is emission from the reverse shock component of the external shock. In addition, we find the implied value of M_jet to be in accordance with theoretical estimates: the baryonic loading is sufficiently small to allow acceleration of the outflow to Gamma > 100.Comment: 4 pages, 2 postscript figures, to appear in "Gamma-Ray Burst and Afterglow Astronomy 2001", Woods Hole; 5-9 Nov, 200

Integrative analysis of large-scale biological data sets

We present two novel web-applications for microarray and gene/protein set analysis, ArrayMining.net and TopoGSA. These bioinformatics tools use integrative analysis methods, including ensemble and consensus machine learning techniques, as well as modular combinations of different analysis types, to extract new biological insights from experimental transcriptomics and proteomics data. They enable researchers to combine related algorithms and datasets to increase the robustness and accuracy of statistical analyses and exploit synergies of different computational methods, ranging from statistical learning to optimization and topological network analysis