Noncommutativity and Duality through the Symplectic Embedding Formalism

This work is devoted to review the gauge embedding of either commutative and noncommutative (NC) theories using the symplectic formalism framework. To sum up the main features of the method, during the process of embedding, the infinitesimal gauge generators of the gauge embedded theory are easily and directly chosen. Among other advantages, this enables a greater control over the final Lagrangian and brings some light on the so-called "arbitrariness problem". This alternative embedding formalism also presents a way to obtain a set of dynamically dual equivalent embedded Lagrangian densities which is obtained after a finite number of steps in the iterative symplectic process, oppositely to the result proposed using the BFFT formalism. On the other hand, we will see precisely that the symplectic embedding formalism can be seen as an alternative and an efficient procedure to the standard introduction of the Moyal product in order to produce in a natural way a NC theory. In order to construct a pedagogical explanation of the method to the nonspecialist we exemplify the formalism showing that the massive NC U(1) theory is embedded in a gauge theory using this alternative systematic path based on the symplectic framework. Further, as other applications of the method, we describe exactly how to obtain a Lagrangian description for the NC version of some systems reproducing well known theories. Naming some of them, we use the procedure in the Proca model, the irrotational fluid model and the noncommutative self-dual model in order to obtain dual equivalent actions for these theories. To illustrate the process of noncommutativity introduction we use the chiral oscillator and the nondegenerate mechanics

Studies of the nucler equation of state using numerical calculations of nuclear drop collisions

A numerical calculation for the full thermal dynamics of colliding nuclei was developed. Preliminary results are reported for the thermal fluid dynamics in such processes as Coulomb scattering, fusion, fusion-fission, bulk oscillations, compression with heating, and collisions of heated nuclei

The Influence of Nuclear Composition on the Electron Fraction in the Post-Core-Bounce Supernova Environment

We study the early evolution of the electron fraction (or, alternatively, the neutron-to-proton ratio) in the region above the hot proto-neutron star formed after a supernova explosion. We study the way in which the electron fraction in this environment is set by a competition between lepton (electron, positron, neutrino, and antineutrino) capture processes on free neutrons and protons and nuclei. Our calculations take explicit account of the effect of nuclear composition changes, such as formation of alpha particles (the alpha effect) and the shifting of nuclear abundances in nuclear statistical equilibrium associated with cooling in near-adiabatic outflow. We take detailed account of the process of weak interaction freeze-out in conjunction with these nuclear composition changes. Our detailed treatment shows that the alpha effect can cause significant increases in the electron fraction, while neutrino and antineutrino capture on heavy nuclei tends to have a buffering effect on this quantity. We also examine the effect on weak rates and the electron fraction of fluctuations in time in the neutrino and antineutrino energy spectra arising from hydrodynamic waves. Our analysis is guided by the Mayle & Wilson supernova code numerical results for the neutrino energy spectra and density and velocity profiles.Comment: 38 pages, AAS LaTeX, 8 figure

Structure of Micro-instabilities in Tokamak Plasmas: Stiff Transport or Plasma Eruptions?

Solutions to a model 2D eigenmode equation describing micro-instabilities in tokamak plasmas are presented that demonstrate a sensitivity of the mode structure and stability to plasma profiles. In narrow regions of parameter space, with special plasma profiles, a maximally unstable mode is found that balloons on the outboard side of the tokamak. This corresponds to the conventional picture of a ballooning mode. However, for most profiles this mode cannot exist and instead a more stable mode is found that balloons closer to the top or bottom of the plasma. Good quantitative agreement with a 1D ballooning analysis is found provided the constraints associated with higher order profile effects, often neglected, are taken into account. A sudden transition from this general mode to the more unstable ballooning mode can occur for a critical flow shear, providing a candidate model for why some experiments observe small plasma eruptions (Edge Localised Modes, or ELMs) in place of large Type I ELMs.Comment: 11 pages, 3 figure

The effect of equine hyperimmune sera on TNF alpha activity in a L929 cell bioassay

In this pilot study we examined the effect of sera from a proprietary hyperimmune plasma product (Equiplas) on the activity of TNF: in an in vitro L929 cell bioassay. In brief, we report observations from 2 accessions of sera. Accession 1 describes the antiTNF: activity of 3 hyperimmune sera and an untreated serum sample that were provided blind to the study. Accession 2 reports a comparison of antiTNFalpha activity found in 3 paired hyperimmune sera collected following a multiple endotoxin vaccination regimen