The Atmosphere Explorer optical glow near perigee altitudes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95658/1/grl2990.pd

Peanut-shaped bulges in face-on disk galaxies

We present high resolution absorption-line spectroscopy of 3 face-on galaxies, NGC 98, NGC 600, and NGC 1703 with the aim of searching for box/peanut (B/P)-shaped bulges. These observations test and confirm the prediction of Debattista et al. (2005) that face-on B/P-shaped bulges can be recognized by a double minimum in the profile of the fourth-order Gauss-Hermite moment h_4. In NGC 1703, which is an unbarred control galaxy, we found no evidence of a B/P bulge. In NGC 98, a clear double minimum in h_4 is present along the major axis of the bar and before the end of the bar, as predicted. In contrast, in NGC 600, which is also a barred galaxy but lacks a substantial bulge, we do not find a significant B/P shape.Comment: 4 pages, 1 figure. To appear in "Tumbling, twisting, and winding galaxies: Pattern speeds along the Hubble sequence", E. M. Corsini and V. P. Debattista (eds.), Memorie della Societa` Astronomica Italian

Scheduling Algorithm for Coordinated Beamforming in Heterogeneous Macro/Pico LTE-Advanced Networks

Pico base stations are an important instrument to increase the capacity of mobile radio networks. Due to the limited spectrum availability it will be necessary to operate macro and pico base stations on the same frequency bands. In this case the transmit power imbalance between different base station types creates new interference situations. Coordinated beamforming is one method of base station cooperation that can be applied to mitigate interference in this scenario. The work presented here describes a scheduler for coordinated beamforming in an LTE-Advanced system which relies on sharing only the feedback information from the mobile stations between the base stations. System level simulation results show that this approach can decrease the interference experienced by the mobile stations attached to the pico base stations

Determinação da taxa de emissão de amônia em cama de aves pelo método da espuma.

Projeto/Plano de Ação: 02.10.06.002

Nesting Induced Precursor Effects: a Renormalization Group Approach

We develop a controlled weak coupling renormalization group (RG) approach to itinerant electrons. Within this formalism we rederive the phase diagram for two-dimensional (2D) non-nested systems. Then we study how nesting modifies this phase diagram. We show that competition between p-p and p-h channels, leads to the manifestation of unstable precursor fixed points in the RG flow. This effect should be experimentally measurable, and may be relevant for an explanation of pseudogaps in the high temperature superconductors (HTC), as a crossover phenomenon.Comment: 4 pages, 4 figures, 1 tabl

Lagrangian formulation for noncommutative nonlinear systems

In this work we use the well known formalism developed by Faddeev and Jackiw to introduce noncommutativity within two nonlinear systems, the SU(2) Skyrme and O(3) nonlinear sigma models. The final result is the Lagrangian formulations for the noncommutative versions of both models. The possibility of obtaining different noncommutative versions for these nonlinear systems is demonstrated.Comment: 8 pages. Revex 4.