Numerical Modelling of Instantaneous Plate Tectonics

Assuming lithospheric plates to be rigid, we systematically invert 68 spreading rates, 62 fracture zones trends and 10^6 earthquake slip vectors simultaneously to obtain a self-consistent model of instantaneous relative motions for eleven major plates. The inverse problem is linearized and solved iteratively by a maximum likelihood procedure. Because the uncertainties in the data are small, Gaussian statistics are shown to be adequate. The use of a linear theory permits (1) the calculation of the uncertainties in the various angular velocity vectors caused by uncertainties in the data, and (2) quantitative examination of the distribution of information within the data set. The existence of a self-consistent model satisfying all the data is strong justification of the rigid plate assumption. Slow movement between North and South America is shown to be resolvable. We then invert the trends of 20 linear island chains and aseismic ridges under the assumptions that they represent the directions of plate motions over a set of hot spots fixed with respect to each other. We conclude that these hot spots have had no significant relative motions in the last 10 My

High p_T Triggered Delta-eta,Delta-phi Correlations over a Broad Range in Delta-eta

The first measurement of pseudorapidity (Delta-eta) and azimuthal angle (Delta-phi) correlations between high transverse momentum charged hadrons (p_T > 2.5 GeV/c) and all associated particles is presented at both short- (small Delta-eta) and long-range (large Delta-eta) over a continuous pseudorapidity acceptance (-4<Delta-eta<2). In these proceedings, the various near- and away-side features of the correlation structure are discussed as a function of centrality in Au+Au collisions measured by PHOBOS at sqrt(s_NN)=200 GeV. In particular, this measurement allows a much more complete determination of the longitudinal extent of the ridge structure, first observed by the STAR collaboration over a limited eta range. In central collisions the ridge persists to at least Delta-eta=4, diminishing in magnitude as collisions become more peripheral until it disappears around Npart=80.Comment: 5 pages, 2 figures, presented at the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur, India, February 4-10, 2008. Full author list included and typo corrected in equation

Characterization of SU(1,1) coherent states in terms of affine group wavelets

The Perelomov coherent states of SU(1,1) are labeled by elements of the quotient of SU(1,1) by the compact subgroup. Taking advantage of the fact that this quotient is isomorphic to the affine group of the real line, we are able to parameterize the coherent states by elements of that group or equivalently by points in the half-plane. Such a formulation permits to find new properties of the SU(1,1) coherent states and to relate them to affine wavelets.Comment: 11 pages, latex, to be published in J. Phys. A : Math. Ge

Equilibration in Quark Gluon Plasma

The hydrodynamic expansion rate of quark gluon plasma (QGP) is evaluated and compared with the scattering rate of quarks and gluons within the system. Partonic scattering rates evaluated within the ambit of perturbative Quantum Choromodynamics (pQCD) are found to be smaller than the expansion rate evaluated with ideal equation of state (EoS) for the QGP. This indicate that during the space-time evolution the system remains out of equilibrium. Enhancement of pQCD cross sections and a more realistic EoS keep the partons closer to the equilibrium.Comment: To be published in the Quark Matter 2008 poster proceeding

Plant roots steer resilience to perturbation of river floodplains

Freshwater ecosystems along river floodplains host among the greatest biodiversity on Earth and are known to respond to anthropic pressure. For water impounded systems, resilience to changes in the natural flow regime is believed to be bi-directional. Whether such resilience prevents the system from returning to pristine conditions after the flow regime changes reverse is as yet unclear, though widely documented. In this work we show that temporal irreversibility of river floodplains to recover their status may be explained by the dynamics of riparian water-tolerant plant roots. Our model is a quantitative tool that will benefit scientists and practitioners in predicting the impact of changing flow regimes on long-term river floodplain dynamics

Heavy Flavor Probes of Quark Matter

A brief survey of the role of heavy flavors as a probe of the state of matter produced by high energy heavy ion collisions is presented. Specific examples include energy loss, initial state gluon saturation, thermalization and flow. The formation of quarkonium bound states from interactions in which multiple heavy quark-antiquark pairs are initially produced is examined in general. Results from statistical hadronization and kinetic models are summarized. New predictions from the kinetic model for J/Psi at RHIC are presented.Comment: Based on invited plenary talk at Strange Quark Matter 2004, Cape Town, South Africa, September 15-20, 2004, references completed, published in J. Phys. G: Nucl. Part. Phys. 31 (2005) S641-S64

Evolution of magnetic polarons and spin-carrier interactions through the metal-insulator transition in Eu1−x_{1-x}Gdx_{x}O

Raman scattering studies as functions of temperature, magnetic field, and Gd-substitution are used to investigate the evolution of magnetic polarons and spin-carrier interactions through the metal-insulator transition in Eu$_{1-x}$Gd$_{x}$O. These studies reveal a greater richness of phase behavior than have been previously observed using transport measurements: a spin-fluctuation-dominated paramagnetic (PM) phase regime for T $>$ T$^{*}$ $>$ T$_{C}$, a two-phase regime for T $<$ T$^{*}$ in which magnetic polarons develop and coexist with a remnant of the PM phase, and an inhomogeneous ferromagnetic phase regime for T $<$ T$_{C}$