Generalized Emission Functions for Photon Emission from Quark-Gluon Plasma

The Landau-Pomeranchuk-Migdal effects on photon emission from the quark gluon plasma have been studied as a function of photon mass, at a fixed temperature of the plasma. The integral equations for the transverse vector function (${\bf \tilde{f}(\tilde{p}_\perp)}$) and the longitudinal function ($\tilde{g}({\bf \tilde{p}_\perp})$) consisting of multiple scattering effects are solved by the self consistent iterations method and also by the variational method for the variable set \{$p_0,q_0,Q^2$\}, considering the bremsstrahlung and the $\bf aws$ processes. We define four new dynamical scaling variables, $x^b_T$,$x^a_T$,$x^b_L$,$x^a_L$ for bremsstrahlung and {\bf aws} processes and analyse the transverse and longitudinal components as a function of \{$p_0,q_0,Q^2$\}. We generalize the concept of photon emission function and we define four new emission functions for massive photon emission represented by $g^b_T$, $g^a_T$, $g^b_L$, $g^a_L$. These have been constructed using the exact numerical solutions of the integral equations. These four emission functions have been parameterized by suitable simple empirical fits. In terms of these empirical emission functions, the virtual photon emission from quark gluon plasma reduces to one dimensional integrals that involve folding over the empirical $g^{b,a}_{T,L}$ functions with appropriate quark distribution functions and the kinematic factors. Using this empirical emission functions, we calculated the imaginary part of the photon polarization tensor as a function of photon mass and energy.Comment: In nuclear physics journals and arxiv listings, my name used to appear as S.V.S. Sastry. Hereafter, my name will appear as, S.V. Suryanarayan

A Stable Non-BPS Configuration From Intersecting Branes and Antibranes

We describe a tachyon-free stable non-BPS brane configuration in type IIA string theory. The configuration is an elliptic model involving rotated NS5 branes, D4 branes and anti-D4 branes, and is dual to a fractional brane-antibrane pair placed at a conifold singularity. This configuration exhibits an interesting behaviour as we vary the radius of the compact direction. Below a critical radius the D4 and anti-D4 branes are aligned, but as the radius increases above the critical value the potential between them develops a minimum away from zero. This signals a phase transition to a configuration with finitely separated branes

Non-segmented negative sense RNA viruses as vectors for vaccine development

This article intends to cover two aspects of non-segmented negative sense RNA viruses. In the initial section, the strategy employed by these viruses to replicate their genomes is discussed. This would help in understanding the later section in which the use of these viruses as vaccine vectors has been discussed. For the description of the replication strategy which encompasses virus genome transcription and genome replication carried out by the same RNA dependent RNA polymerase complex, a member of the prototype rhabdovirus family-Chandipura virus has been chosen as an example to illustrate the complex nature of the two processes and their regulation. In the discussion on these viruses serving as vectors for carrying vaccine antigen genes, emphasis has been laid on describing the progress made in using the attenuated viruses as vectors and a description of the systems in which the efficiency of immune responses has been tested

Stable Non-BPS States and Their Holographic Duals

Stable non-BPS states can be constructed and studied in a variety of contexts in string theory. Here we review some interesting constructions that arise from suspended and wrapped branes. We also exhibit some stable non-BPS states that have holographic duals.Comment: 10 pages, LaTeX, 10 .eps figures (included); based on a talk given at Strings 2000, Michiga