A meson-exchange piN model up to energies sqrt(s) < 2.0 GeV

A meson-exchange piN model, previously constructed using three-dimensional reduction scheme of the Bethe-Salpeter equation for a model Lagrangian involving \pi, \eta, N, \Delta, rho, and \sigma fields, is extended to energies up to 2 GeV by including the \eta N channel and all the four stars \pi N resonances up to the F-waves. The effects of other 2 pion channels are taken into account phenomenologically. The extended model gives an excellent fit to both piN phase shifts and inelasticity parameters in all channels up to the F-waves. However, a few of the extracted resonance parameters differ considerably from the PDG values.Comment: 5 pages, 1 figire, 1 table. Talk presented at the 18th International Conference on "Few-Body Problems in Physics", Aug. 21-26, 2006, Santos, Brazi

Electrocardiogram events detection

This work aims to create a system of medical diagnosis of the Electrocardiogram (ECG). The events of the ECG are related with the functioning of the heart and different disorders of the heart functioning have their own ECG pattern allowing the connection between ECG patterns and cardiac disorders. For this purpose, we present here an algorithm that detects the P, QRS and T events of the ECG under MATLAB environment. The algorithm is based in two techniques. The search for picks and valleys and the search of event using a known patter and the correlation with ECG signal inside of a previously detected period. Finally the results are presented and discussed

Yield Strength Analysis by Small Punch Test Using Inverse Finite Element Method

AbstractConsidering the change of material behavior in in-service component due to temperature, loading and irradiation, several micro-specimen techniques have been proposed to describe deformation and fracture behaviors of materials under different conditions. This paper investigates the mechanical characterization of materials by the experimental and numerical method of small punch test. A two-dimensional finite element model was established to simulate the deformation behavior of X80. The resulting Load-Displacement curve contains key information about the mechanical properties of the tested materials. Thus, an application of inverse finite element method was used in the investigation of mechanical properties of materials which have been tested by small punch test. The difference between experiment and simulation curves was defined as objective function based upon the calculation model established by ABAQUS and MATLAB procedure. Finally, the estimated results suggested confidence in the analysis of the inverse finite element method for material's yield strength

Instability of generalised AdS black holes and thermal field theory

We study black holes in AdS-like spacetimes, with the horizon given by an arbitrary positive curvature Einstein metric. A criterion for classical instability of such black holes is found in the large and small black hole limits. Examples of large unstable black holes have a B\"ohm metric as the horizon. These, classically unstable, large black holes are locally thermodynamically stable. The gravitational instability has a dual description, for example by using the $AdS_7 \times S^4$ version of the AdS/CFT correspondence. The instability corresponds to a critical temperature of the dual thermal field theory defined on a curved background.Comment: 1+16 pages. 1 figure. LaTeX. Minor clarification

Threshold pi^0 photo- and electro-production in a meson-exchange model

We show that, within a meson-exchange dynamical model describing well most of the existing pion electromagnetic production data up to the second resonance region, one is also able to obtain a good agreement with the pi^0 photo- and electroproduction data near threshold. In the case of pi^0 production, the effects of final state interaction in the threshold region are nearly saturated by single charge exchange rescattering. This indicates that in ChPT, it might be sufficient to carry out the calculation just up to one-loop diagrams for threshold neutral pion production.Comment: 6 pages LATEX including 1 tables and 4 figures, uses espcrc1.st

Long-term fertilization effects on crop yield and nitrate-N accumulation in soil in northwestern China

Non-Peer Reviewe

π0 Photo- and electroproduction at threshold within a dynamical model

AbstractWe show that, within a meson-exchange dynamical model describing most of the existing pion electromagnetic production data up to the second resonance region, one is also able to obtain a good agreement with the π0 photo- and electroproduction data near threshold. The potentials used in the model are derived from an effective chiral Lagrangian. The only sizable discrepancy between our results and the data is in the P-wave amplitude P3=2M1++M1− where our prediction underestimate the data by about 20%. In the case of π0 production, the effects of final state interaction in the threshold region are nearly saturated by single charge exchange rescattering. This indicates that in ChPT it might be sufficient to carry out the calculation just up to one-loop diagrams for threshold neutral pion production

Isotropy Properties of the Multi-Step Markov Symbolic Sequences

A new object of the probability theory, the two-sided chain of symbols (introduced in Ref. arXiv:physics/0306170) is used to study isotropy properties of binary multi-step Markov chains with the long-range correlations. Established statistical correspondence between the Markov chains and certain two-sided sequences allows us to prove the isotropy properties of three classes of the Markov chains. One of them is the important class of weakly correlated additive Markov chains, which turned out to be equivalent to the additive two-sided sequences.Comment: 7 page

Medium Effects in Coherent Pion Photo- and Electroproduction on 4He and 12C

Coherent pi0 photo- and electroproduction on 4He and 12C nuclei is investigated in the framework of a distorted wave impulse approximation in momentum space. The elementary process is described by the recently developed unitary isobar model. Medium effects are considered by introducing a phenomenological Delta self-energy. The recent experimental data for 4He and 12C can be well described over a wide range of energies and emission angles by the assumption that the Delta-nuclear interaction saturates.Comment: 18 pages LaTeX including 7 postscript figure

The mechanism of striation formation in plasma display panels

Despite the high pressure employed in plasma display panels, the energy balance of low-energy electrons is found to be dominated by inelastic collisions, and the resulting nonlocal electron kinetics plays a key role in the striation formation. Surface charge accumulation on the anode dielectric, however, is also needed for striations to form. It is the combined effect of surface charges and nonlocal electron kinetics that results in the striation formation in plasma display panel cells. Two-dimensional fluid simulations, which assume local electron kinetics, and two-dimensional particle-in-cell Monte Carlo collision simulations with a bare conducting anode show that striations do not form if either the nonlocal electron kinetics or the surface charge accumulation is not considered