Identification of four RXTE Slew Survey sources with nearby luminous active galactic nuclei

Based on RXTE scans and observations with the SWIFT/XRT telescope and INTEGRAL observatory, we report the identification of four X-ray sources discovered during the RXTE Slew Survey of the |b|>10deg sky with nearby (z ~ 0.017-0.098) luminous (log L_2-10keV ~ 42.7-44 erg/s) active galactic nuclei. Two of the objects exhibit heavily intrinsically absorbed X-ray spectra (NHL~10^23 cm^-2).Comment: 4 pages, 2 figures. Sibmitted to Astronomy and Astrophysics Letter

The future of universal access? merging computing, design and engineering

Technology is advancing at a fast pace while the shape and nature of computers continues to evolve, with tablets and smartphones illustrating the move away from the traditional notion of a laptop or desktop computer. Similarly, networking and sensing technologies are also developing rapidly and innovatively. All of these technologies have the potential to enfranchise users with severe functional impairments to be better able to control and interact with other people and their surroundings. However, this is only possible if those designing the novel systems based upon these new technologies consider such users’ needs explicitly. This paper examines how these technological advances can be employed to support these users in the near future. The paper further discusses issues such as the need for security as systems evolve from control of specific environments to a potential model for interaction in any location

Temporal Evolution of the Vela Pulsar's Pulse Profile

The mechanisms of emission and changes in rotation frequency ('glitching') of the Vela pulsar (J0835-4510) are not well understood. Further insight into these mechanisms can be achieved by long-term studies of integrated pulse width, timing residuals, and bright pulse rates. We have undertaken an intensive observing campaign of Vela and collected over 6000 hours of single pulse data. The data shows that the pulse width changes with time, including marked jumps in width after micro-glitches (frequency changes). The abundance of bright pulses also changes after some micro-glitches, but not all. The secular changes in pulse width have three possible cyclic periods, that match with X-ray periodicities of a helical jet that are interpreted as free precession.Comment: 6 pages, 8 figures. Accepted for publication in The Astrophysical Journa

A High Galactic Latitude HI 21cm-line Absorption Survey using the GMRT: I. Observations and Spectra

We have used the Giant Meterwave Radio Telescope (GMRT) to measure the Galactic HI 21-cm line absorption towards 102 extragalactic radio continuum sources, located at high (|b| >15deg.) Galactic latitudes. The Declination coverage of the present survey is Decl. ~ -45deg.. With a mean rms optical depth of ~0.003, this is the most sensitive Galactic HI 21-cm line absorption survey to date. To supplement the absorption data, we have extracted the HI 21-cm line emission profiles towards these 102 lines of sight from the Leiden Dwingeloo Survey of Galactic neutral hydrogen. We have carried out a Gaussian fitting analysis to identify the discrete absorption and emission components in these profiles. In this paper, we present the spectra and the components. A subsequent paper will discuss the interpretation of these results.Comment: 46 pages, Accepted for publication in Journal of Astrophysics & Astronom

Observation of polarization domain wall solitons in weakly birefringent cavity fiber lasers

We report on the experimental observation of two types of phase-locked vector soliton in weakly birefringent cavity erbium-doped fiber lasers. While a phase-locked dark-dark vector soliton was only observed in fiber lasers of positive dispersion, a phase-locked dark-bright vector soliton was obtained in fiber lasers of either positive or negative dispersion. Numerical simulations confirmed the experimental observations, and further showed that the observed vector solitons are the two types of phase-locked polarization domain-wall solitons theoretically predicted.Comment: 14 pages, 4 Figure

Courant-like brackets and loop spaces

We study the algebra of local functionals equipped with a Poisson bracket. We discuss the underlying algebraic structures related to a version of the Courant-Dorfman algebra. As a main illustration, we consider the functionals over the cotangent bundle of the superloop space over a smooth manifold. We present a number of examples of the Courant-like brackets arising from this analysis.Comment: 20 pages, the version published in JHE

Statistical analysis of general aviation VG-VGH data

To represent the loads spectra of general aviation aircraft operating in the Continental United States, VG and VGH data collected since 1963 in eight operational categories were processed and analyzed. Adequacy of data sample and current operational categories, and parameter distributions required for valid data extrapolation were studied along with envelopes of equal probability of exceeding the normal load factor (n sub z) versus airspeed for gust and maneuver loads and the probability of exceeding current design maneuver, gust, and landing impact n sub z limits. The significant findings are included