Angular momentum transport and disk morphology in SPH simulations of galaxy formation

We perform controlled N-Body/SPH simulations of disk galaxy formation by cooling a rotating gaseous mass distribution inside equilibrium cuspy spherical and triaxial dark matter halos. We systematically study the angular momentum transport and the disk morphology as we increase the number of dark matter and gas particles from 10^4 to 10^6, and decrease the gravitational softening from 2 kpc to 50 parsecs. The angular momentum transport, disk morphology and radial profiles depend sensitively on force and mass resolution. At low resolution, similar to that used in most current cosmological simulations, the cold gas component has lost half of its initial angular momentum via different mechanisms. The angular momentum is transferred primarily to the hot halo component, by resolution-dependent hydrodynamical and gravitational torques, the latter arising from asymmetries in the mass distribution. In addition, disk-particles can lose angular momentum while they are still in the hot phase by artificial viscosity. In the central disk, particles can transfer away over 99% of their initial angular momentum due to spiral structure and/or the presence of a central bar. The strength of this transport also depends on force and mass resolution - large softening will suppress the bar instability, low mass resolution enhances the spiral structure. This complex interplay between resolution and angular momentum transfer highlights the complexity of simulations of galaxy formation even in isolated haloes. With 10^6 gas and dark matter particles, disk particles lose only 10-20% of their original angular momentum, yet we are unable to produce pure exponential profiles.Comment: 17 pages, 16 figures, MNRAS accepted. Minor changes in response to referee comments. High resolution version of the paper can be found at http://krone.physik.unizh.ch/~tkaufman/papers.htm

A parallel H.264/SVC encoder for high definition video conferencing

In this paper we present a video encoder specially developed and configured for high definition (HD) video conferencing. This video encoder brings together the following three requirements: H.264/Scalable Video Coding (SVC), parallel encoding on multicore platforms, and parallel-friendly rate control. With the first requirement, a minimum quality of service to every end-user receiver over Internet Protocol networks is guaranteed. With the second one, real-time execution is accomplished and, for this purpose, slice-level parallelism, for the main encoding loop, and block-level parallelism, for the upsampling and interpolation filtering processes, are combined. With the third one, a proper HD video content delivery under certain bit rate and end-to-end delay constraints is ensured. The experimental results prove that the proposed H.264/SVC video encoder is able to operate in real time over a wide range of target bit rates at the expense of reasonable losses in rate-distortion efficiency due to the frame partitioning into slices

Methyl 1H-pyrrole-2-carboxyl­ate

The title compound, C6H7NO2, is essentially planar with a dihedral angle of 3.6 (3)° between the pyrrole ring and the methoxy­carbonyl O/C/O/C plane. In the crystal structure, the N atom is a hydrogen-bond donor to the carboxylate C=O O atom of the neighboring mol­ecule. These inter­molecular hydrogen bonds lead to the formation of helical chains along the b axis

ACTA: A Tool for Argumentative Clinical Trial Analysis

International audienceArgumentative analysis of textual documents of various nature (e.g., persuasive essays, online discussion blogs, scientific articles) allows to detect the main argumentative components (i.e., premises and claims) present in the text and to predict whether these components are connected to each other by argumentative relations (e.g., support and attack), leading to the identification of (possibly complex) argumentative structures. Given the importance of argument-based decision making in medicine, in this demo paper we introduce ACTA, a tool for automating the argumentative analysis of clinical trials. The tool is designed to support doctors and clinicians in identifying the document(s) of interest about a certain disease, and in analyzing the main argumentative content and PICO elements