Tidal scattering of stars on supermassive black holes in galactic centers

Some of the mass that feeds the growth of a massive black hole (BH) in a galactic center is supplied by tidal disruption of stars that approach it on unbound, low angular momentum orbits. For each star that is disrupted, others narrowly escape after being subjected to extreme tidal distortion, spin-up, mixing and mass-loss, which may affect their evolution and appearance. We show that it is likely that a significant fraction of the stars around massive BHs in galactic centers have undergone such extreme tidal interactions and survived subsequent total disruption, either by being deflected off their orbit or by missing the BH due to its Brownian motion. We discuss possible long-term observable consequences of this process, which may be relevant for understanding the nature of stars in galactic centers, and may provide a signature of the existence of massive BHs there.Comment: 5 pages 4 figures. ApJL in press, minor changes to reflect journal version including redifinition of unbound tidally disturbed stars and additional reference

High Performance Associative Memories and Structured Weight Dilution

Copyright SpringerThe consequences of two techniques for symmetrically diluting the weights of the standard Hopfield architecture associative memory model, trained using a non-Hebbian learning rule, are examined. This paper reports experimental investigations into the effect of dilution on factors such as: pattern stability and attractor performance. It is concluded that these networks maintain a reasonable level of performance at fairly high dilution rates

Global and Feature Based Gender Classification of Faces: A Comparison of Human Performance and Computational Models

Original paper can be found at: http://eproceedings.worldscinet.com/9789812701886/9789812701886_0036.html Copyright World Scientific Publishing Company. http://dx.doi.org/10.1142/9789812701886_0036Most computational models for gender classification use global information (the full face image) giving equal weight to the whole face area irrespective of the importance of the internal features. Here, we use a global and feature based representation of face images that includes both global and featural information. We use dimensionality reduction techniques and a support vector machine classifier and show that this method performs better than either global or feature based representations alone.Peer reviewe

Evaluating Alternative Safety Net Programs in Alberta: A Firm-level Simulation Analysis

This paper examines alternative risk management strategies in terms of their effectiveness for three representative Alberta farm operations. Stochastic dynamic simulation methods are used to model financial performance for these farms, and alternative risk management programs are compared in terms of their ability to stabilize returns, support income and reduce the probability of bankruptcy. The results suggest that government programs such as the Net Income Stabilization Account (NISA) program or the Farm Income Disaster Program (FIDP) in Alberta have some benefits in terms of supporting income levels and reducing the chances of farm failure. Neither program is very effective, however, in stabilizing year to year income or cash flow for the farm operations. As a risk management program, FIDP is more effective than NISA but this improved performance comes at the price of higher government costs. Performance of NISA and FIDP, relative to alternative risk management programs and strategies such as forward contracting or crop insurance, is mixed. In some cases, NISA does not seem to provide benefits beyond those available from other strategies, while FIDP tends to perform better than the alternatives. Finally, while increased debt load weakens firm financial performance, NISA and FIDP still provide some benefits in terms of supporting income and reducing the probability of bankruptcy.Farm Management, Risk and Uncertainty,

Precision tunable resonant microwave cavity

A tunable microwave cavity containing ionizable metallic vapor or gases and an apparatus for precisely positioning a microwave coupling tip in the cavity and for precisely adjusting at least one dimension of the cavity are disclosed. With this combined structure, resonance may be achieved with various types of ionizable gases. A coaxial probe extends into a microwave cavity through a tube. One end of the tube is retained in a spherical joint attached in the cavity wall. This allows the coaxial probe to be pivotally rotated. The coaxial probe is slideable within the tube thus allowing the probe to be extended toward or retracted from the center of the cavity

Flexible Pricing and Payment Alternatives on Canadian Wheat Board Pooling For Wheat

Crop Production/Industries, Marketing,

PORK RISK MANAGEMENT STRATEGIES FOR THE ALBERTA HOG INDUSTRY

Risk and Uncertainty,

A neural network model of visual object recognition impairment after brain damage

Dysfunction of the visual object recognition system in humans is briefly discussed and a basic connectionist model of visual object recognition is introduced. Experimentation in which two variants of this model are lesioned is undertaken. The results suggest that the well documented phenomenon of superordinate preservation is model independent. Differential category specific recognition deficits are also observed in this model, however these are sensitive to each particular variant

Combining QCD and electroweak corrections to dilepton production in FEWZ

We combine the next-to-next-to-leading order (NNLO) QCD corrections to lepton-pair production through the Drell-Yan mechanism with the next-to-leading order (NLO) electroweak corrections within the framework of the FEWZ simulation code. Control over both sources of higher-order contributions is necessary for measurements where percent-level theoretical predictions are crucial, and in phase-space regions where the NLO electroweak corrections grow large. The inclusion of both corrections in a single simulation code eliminates the need to separately incorporate such effects as final-state radiation and electroweak Sudakov logarithms when comparing many experimental results to theory. We recalculate the NLO electroweak corrections in the complex-mass scheme for both massless and massive final-state leptons, and modify the QCD corrections in the original FEWZ code to maintain consistency with the complex-mass scheme to the lowest order. We present phenomenological results for LHC studies that include both NNLO QCD and NLO electroweak corrections. In addition, we study several interesting kinematics features induced by experimental cuts in the distribution of photon radiation at the LHC.Comment: 21 pages, 13 figure