The Parthenon, August 31, 2012

The Parthenon, Marshall University’s student newspaper, is published by students Monday through Friday during the regular semester and weekly Thursday during the summer. The editorial staff is responsible for the news and the editorial content

Electromagnetic Form Factors of the SU(3) Octet Baryons in the semibosonized SU(3) Nambu-Jona-Lasinio Model

The electromagnetic form factors of the SU(3) octet baryons are investigated in the semibosonized SU(3) Nambu--Jona-Lasinio model (chiral quark-soliton model). The rotational $1/N_c$ and strange quark mass corrections in linear order are taken into account. The electromagnetic charge radii of the nucleon and magnetic moments are also evaluated. It turns out that the model is in a remarkable good agreement with the experimental data.Comment: RevTex is used. 37 pages. The final version to appear in Phys. Rev. D. 13 figures are include

Baryons as non-topological chiral solitons

The present review gives a survey of recent developments and applications of the Nambu--Jona-Lasinio model with $N_f=2$ and $N_f=3$ quark flavors for the structure of baryons. The model is an effective chiral quark theory which incorporates the SU(N$_f$)$_L\otimes$SU(N$_f$)$_R\otimes$U(1)$_V$ approximate symmetry of Quantum chromodynamics. The approach describes the spontaneous chiral symmetry breaking and dynamical quark mass generation. Mesons appear as quark-antiquark excitations and baryons arise as non-topological solitons with three valence quarks and a polarized Dirac sea. For the evaluation of the baryon properties the present review concentrates on the non-linear Nambu--Jona-Lasinio model with quark and Goldstone degrees of freedom which is identical to the Chiral quark soliton model obtained from the instanton liquid model of the QCD vacuum. In this non-linear model, a wide variety of observables of baryons of the octet and decuplet is considered. These include, in particular, electromagnetic, axial, pseudoscalar and pion nucleon form factors and the related static properties like magnetic moments, radii and coupling constants of the nucleon as well as the mass splittings and electromagnetic form factors of hyperons. Predictions are given for the strange form factors, the scalar form factor and the tensor charge of the nucleon.Comment: 104 pages, 27 figures as uuencoded and compressed postscript files , hardcopy available upon request; Prog.Part.Nucl.Phys. 37 (1996) (in print

Computational Modeling of Silicate Glasses: A Quantitative Structure-Property Relationship Perspective

This article reviews the present state of Quantitative Structure-Property Relationships (QSPR) in glass design and gives an outlook into future developments. First an overview is given of the statistical methodology, with particular emphasis to the integration of QSPR with molecular dynamics simulations to derive informative structural descriptors. Then, the potentiality of this approach as a tool for interpretative and predictive purposes is highlighted by a number of recent inspiring applications

Climatic variations of the work done by the wind on the ocean's general circulation

The Southern Hemisphere westerlies exert an important influence on global climate, supplying nearly half of the mechanical energy for the deep overturning circulation. In a coarse-resolution ocean model, northward-shifted winds increase the work done on surface geostrophic flows due to enhanced velocities associated with the Antarctic Circumpolar Current (ACC). Alternatively, energy supply is diminished by southward-shifted winds, primarily through reduced correspondence between wind stress and surface velocity in the Southern Ocean due to dynamical and topographic constraints on the ACC. When combined perturbations in latitude and magnitude of the westerlies are applied, these results are reconciled with estimates of recent trends in wind work and volume transport in the Southern Ocean from observations and coupled climate models. This indicates that the strength of the winds exerts a dominant effect that masks the opposing consequences of latitudinal migration. In particular, transport through Drake Passage shows a clear relationship with wind work and velocity when the winds move poleward leading to a reduction in all three quantities. However, under equatorward-shifted winds, stronger polar easterlies adjacent to the Antarctic continent establishes a recirculation gyre leading to increased mechanical energy input and swifter currents but reduced transport. Significant (O(25%)) changes in the mechanical energy supply from the winds may be possible on climatic time scales, particularly associated with the spatial correlation between winds and the ACC that does not depend critically on unresolved eddy processes in this model, leading to a pathway for altering abyssal diapycnal mixing rates and stratification of the ocean interior