X-Ray Bursts from the Galactic X-Ray Transient Source GRS 1915+105

We have analyzed publicly available RXTE/PCAs archival data of GRS 1915+105 during its burst/flaring state. The burst cycle ranges from 30 to 1300 s. These bursts are different from the type I and type II classical bursts seen in Low Mass X-ray Binaries (LMXBs) in terms of their temporal and spectral properties. We have classified these bursts on the basis of properties observed during the quiescent (low flux) phase. The 2 - 10 Hz QPOs are present during the quiescent phase and disappear during the burst phase of all types of these X-ray bursts. The duration of the quiescent phase can be explained assuming an outflow from the post-shock regions and the catastrophic Compton cooling.Comment: 5 pages with two figures, 33rd COSPAR, Warsaw, Poland, July 16-22, 200

Can inflationary models of cosmic perturbations evade the secondary oscillation test?

We consider the consequences of an observed Cosmic Microwave Background (CMB) temperature anisotropy spectrum containing no secondary oscillations. While such a spectrum is generally considered to be a robust signature of active structure formation, we show that such a spectrum {\em can} be produced by (very unusual) inflationary models or other passive evolution models. However, we show that for all these passive models the characteristic oscillations would show up in other observable spectra. Our work shows that when CMB polarization and matter power spectra are taken into account secondary oscillations are indeed a signature of even these very exotic passive models. We construct a measure of the observability of secondary oscillations in a given experiment, and show that even with foregrounds both the MAP and \pk satellites should be able to distinguish between models with and without oscillations. Thus we conclude that inflationary and other passive models can {\em not} evade the secondary oscillation test.Comment: Final version accepted for publication in PRD. Minor improvements have been made to the discussion and new data has been included. The conclusions are unchagne

Scalable Massively Parallel Artificial Neural Networks

There is renewed interest in computational intelligence, due to advances in algorithms, neuroscience, and computer hardware. In addition there is enormous interest in autonomous vehicles (air, ground, and sea) and robotics, which need significant onboard intelligence. Work in this area could not only lead to better understanding of the human brain but also very useful engineering applications. The functioning of the human brain is not well understood, but enormous progress has been made in understanding it and, in particular, the neocortex. There are many reasons to develop models of the brain. Artificial Neural Networks (ANN), one type of model, can be very effective for pattern recognition, function approximation, scientific classification, control, and the analysis of time series data. ANNs often use the back-propagation algorithm for training, and can require large training times especially for large networks, but there are many other types of ANNs. Once the network is trained for a particular problem, however, it can produce results in a very short time. Parallelization of ANNs could drastically reduce the training time. An object-oriented, massively-parallel ANN (Artificial Neural Network) software package SPANN (Scalable Parallel Artificial Neural Network) has been developed and is described here. MPI was use

Dark Matter Search with CUORE-0 and CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale experiment made of TeO2 bolometers that will probe the neutrinoless double beta decay of 130Te. Excellent energy resolution, low threshold and low background make CUORE sensitive to nuclear recoils, allowing a search for dark matter interactions. With a total mass of 741 kg of TeO2, CUORE can search for an annual modulation of the counting rate at low energies. We present data obtained with CUORE-like detectors and the prospects for a dark matter search in CUORE-0, a 40-kg prototype, and CUORE

Modelling and control design for free air carbon dioxide enrichment (FACE) systems

Proportional-integral-plus (PIP) control is employed to maintain gas concentration in a small-scale free air carbon dioxide enrichment (FACE) system. FACE systems are designed to produce controlled concentrations of elevated carbon dioxide, or other atmospheric gases, enabling plant growth experiments to be carried out for in situ vegetation without the use of chambers or other enclosures. Current FACE systems employ control algorithms based on classically derived two- or three-term control laws with manually tuned parameters. However, small FACE plots are more susceptible to turbulent eddies than larger scale systems, making control of concentration particularly difficult. The research described in the present paper employs data from planned FACE experiments to develop PIP control algorithms exploiting model-based predictive control action. Initial trials utilizing this approach yield good results for a small-scale FACE system operating in an uncut arable meadow