162 research outputs found
Postural Stability Variables for Dynamic Equilibrium
Source at http://www.jnsci.org/index.php.Experiments on the maintenance of postural stability on flat stationary support surfaces (quiet standing) that show only limited modes of the potential configurations of balance stability have dominated investigations of balance in quiet upright standing. Recent studies have revealed coordination properties of the whole body in maintaining dynamic postural stability with the application of moving platform paradigms. This paper examines properties of candidate collective variables for postural control within the dynamic systems framework. Evidence is discussed in this paper for: (i) self-organization properties of dynamic postural balance; (ii) enhanced variability and entropy prior to a phase transition between center of mass and center of pressure coupling; (iii) co-existence of intermittent postural control strategies that oscillate between periodic to chaotic transitions to maintain upright postural balance. These collective findings indicate postural attractor dynamic states progressively emerge to the changing task constraints of a moving platform revealing insights into the deterministic and stochastic properties of the multiple time scales of human postural behavior
Symmetry Breaking for Rho Meson in Neutron Matter
Qualitative changes in the collective excitation spectra of the -meson
triplet in neutron matter is studied, with particular emphasis on the breaking
of the discrete symmetry. The appearance of additional
branches in the dispersion characteristics, the mass splitting among the charge
states, the splitting between longitudinal and transverse modes of the
mesons and the appearance of `island' modes (or loops) in the
time-like region are some of the features that are exposed.Comment: Plain LaTeX fil
Matter induced rho-omega mixing
A novel mechanism for mixing induced by neutron-proton
asymmetry in nuclear matter is uncovered and the variation of the mixing angle
with the extent of asymmetry is presented.Comment: Contains two postscript figures in the uuencoded fil
Meson Mixing and Dilepton Production in Heavy Ion Collisions
We study the possibility of mixing via N-N excitations in dense
nuclear matter. This mixing is found to induce a peak in the dilepton spectra
at an invariant mass equal to that of the . We calculate the cross section
for dilepton production through mixing and we compare its size with that of
annihilation. In-medium masses and mixing angles are also calculated.
Some preliminary results of the mixing effect on the dilepton production rates
at finite temperature are also presented.Comment: To be published in the proceedings of CIPANP 200
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