An Extremal Chiral Primary Three-Point Function at Two-loops in ABJ(M)

archiveprefix: arXiv primaryclass: hep-th reportnumber: QMUL-PH-14-23 slaccitation: %%CITATION = ARXIV:1411.0626;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: QMUL-PH-14-23 slaccitation: %%CITATION = ARXIV:1411.0626;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: QMUL-PH-14-23 slaccitation: %%CITATION = ARXIV:1411.0626;%

Simulating gravitational motion, gas dynamics, and structure in the cosmos

We provide introductory explanations and illustrations of the $N$-body hydrodynamics code Charm N-body GrAvity solver (ChaNGa). ChaNGa simulates the gravitational motion and gas dynamics of matter in space, with the goal of modeling galactic and/or cosmological structure and evolution. We discuss the algorithm for leapfrog integration and smoothed particle hydrodynamics and computer science concepts used by the program, including the binary data structure for the particle positions. Our presentation borrows from the doctoral dissertation of J.\ G.\ Stadel. Problems are provided in order to use ChaNGa to learn or solidify some cosmological concepts.Comment: Accepted by the American Journal of Physics. Two important supplementary documents are include

Impact of Glass Cockpit Experience on Manual Flight Skills

Modern aircraft employ a wide variety of advanced flight instrument systems that have been designed to reduce pilot workload and promote safe, efficient flight operations. Research to date on advanced flight instrumentation has primarily focused on mode confusion or pilot misinterpretation of system information. A few studies have also identified pilot concern with a reduction in manual flight skills as a result of regular operation in automated modes. This paper addresses that concern in an attempt to identify factors useful to flight curriculum development. Study participants included 110 experienced airline, corporate, and military pilots who were surveyed before and after a training session in a transport category flight training device with round dial instrumentation. An experienced instructor rated participant flight skills during the simulator activity. Study findings suggest that pilots who are more likely to use automated modes of modern glass cockpit aircraft have a less effective crosscheck and reduced manual flight skills. Issues related to advanced flight deck operations and training are discussed

Enrichment and association of lead and bacteria at particulate surfaces in a salt-marsh surface layer

The particle-laden surface layer (~ 150-370 µm) and subsurface waters of a South San Francisco Bay salt marsh were sampled over two tidal cycles and analyzed for particle numbers and particulate-associated and total concentrations of lead and bacteria…

Thermodynamic properties of spin-1/2 transverse XY chain with Dzyaloshinskii-Moriya interaction: Exact solution for correlated Lorentzian disorder

We extend the consideration of the spin-1/2 transverse XY chain with correlated Lorentzian disorder (Phys. Rev. B {\bf 55,} 14298 (1997)) for the case of additional Dzyaloshinskii-Moriya interspin interaction. It is shown how the averaged density of states can be calculated exactly. Results are presented for the density of states and the transverse magnetization.Comment: 2 figure

Instability of a two-dimensional extremal black hole

We consider the perturbation of tachyon about the extremal ground state of a two-dimensional (2D) electrically charged black hole. It is found that the presenting potential to on-coming tachyonic wave takes a double-humped barrier well. This allows an exponentially growing mode with respect to time. This extremal ground state is classically unstable. We conclude that the 2D extremal electrically charged black hole cannot be a candidate for the stable endpoint of the Hawking evaporation.Comment: 9 pages 2 figures, RevTeX, to be published in Phys. Rev D, to obtain gifures contact Author ([email protected]

Whirling Hexagons and Defect Chaos in Hexagonal Non-Boussinesq Convection

We study hexagon patterns in non-Boussinesq convection of a thin rotating layer of water. For realistic parameters and boundary conditions we identify various linear instabilities of the pattern. We focus on the dynamics arising from an oscillatory side-band instability that leads to a spatially disordered chaotic state characterized by oscillating (whirling) hexagons. Using triangulation we obtain the distribution functions for the number of pentagonal and heptagonal convection cells. In contrast to the results found for defect chaos in the complex Ginzburg-Landau equation and in inclined-layer convection, the distribution functions can show deviations from a squared Poisson distribution that suggest non-trivial correlations between the defects.Comment: 4 mpg-movies are available at http://www.esam.northwestern.edu/~riecke/lit/lit.html submitted to New J. Physic

MeV measurements of γ-ray bursts by CGRO-COMPTEL: Revised catalog

The imaging COMPTEL telescope has accumulated 0.1–30 MeV spectra, time-histories, and positions of more than forty γ-ray bursts within its ∼3 sr field of view in the eight years since its launch. CGRO-COMPTEL measures in both imaging “telescope” and single detector “burst spectroscopy” mode. In an ongoing collaboration with BACODINE/GCN, bursts are imaged automatically, with localizations relayed to a global network of multiwavelength observers in near real time (∼10 minutes). We have updated our burst search procedure in two ways: 1) using more sensitive search algorithms; and 2) using data from more detectors. The first are double change-point algorithms. With these we can find regions of significant excess flux with no assumptions on the wide range of burst time-scales (e.g., rise-times or decay-times) or intensities, and only one adjustable parameter (the time-averaged count-rate of the detectors). This makes it simpler to combine information on burst time-histories from the larger effective area (but cruder time bins) burst spectroscopy detectors, and hence better pinpoint the best times for imaging each burst. We report the eight bursts detected during 1998–1999

Spectra of a recent bright burst measured by CGRO-COMPTEL: GRB 990123

CGRO-COMPTEL measures gamma-ray burst positions, time-histories and spectra in the 0.1–30 MeV energy range, in both imaging “telescope” and single detector “burst spectroscopy” mode. GRB 990123, one of the most recent bright bursts seen by COMPTEL, was caught in the optical while the gamma-ray emission was ongoing. The burst spectral shape can be characterized by a peak in ν−Fν just below 1 MeV and a power-law tail above(photon index∼−2.4,) and flattening below. There is also spectral evolution by downward movement of the peak and/or softening of the power laws. We present light-curves, time resolved spectra and an image map for this burst