Novel features of J/ΨJ/\Psi dissociation in matter

We make a detailed study of the effect that the recently predicted modification of the in-medium masses of charmed mesons would have on $J/\Psi$ dissociation on pion and $\rho$-meson comovers in relativistic heavy ion collisions. We find a substantial dependence of the $J/\Psi$ absorption rates on the density and temperature of the nuclear matter. This suggests that a quantitative analysis of $J/\Psi$ dissociation in nucleus nucleus collisions should include the effects of the modification of meson masses in dense matter.Comment: 7 pages, espcrc2, including 5 ps-figures, to be pub. in Phys. Lett.

Inverse Slope Systematics in High-Energy p+p and Au+Au Reactions

We employ the Monte-Carlo PYTHIA to calculate the transverse mass spectra of various hadrons and their inverse slopes T* at m_T-m=1.5-2 GeV in p+p reactions at sqrt(s)=200 GeV. Due to (multiple) minijet production T* increases as a function of the hadron mass. Moreover, the T*(m) systematics has a ``discontinuity'' at the charm threshold, i.e. the inverse slope of D-mesons is much higher than that of non-charmed hadrons and even of the heavier Lambda_C baryon. The experimental observation of this characteristic behaviour in Au+Au collisions would indicate the absence of c-quark rescattering. In contrast, the assumption of thermalized partons and hydrodynamical evolution would lead to a smoothly increasing T*(m), without discontinuity at the charm threshold. The degree of collective transverse flow, indicated by the slope of the T*(m) systematics, depends strongly on whether kinetic equilibrium is maintained for some time after hadronization or not.Comment: 14 pages, 2 figures, REVTEX; mistake in plot of c-quark mt-distribution corrected, some references adde

Hydrodynamical assessment of 200 AGeV collisions

We are analyzing the hydrodynamics of 200 A GeV S+S collisions using a new approach which tries to quantify the uncertainties arising from the specific implementation of the hydrodynamical model. Based on a previous phenomenological analysis we use the global hydrodynamics model to show that the amount of initial flow, or initial energy density, cannot be determined from the hadronic momentum spectra. We additionally find that almost always a sizeable transverse flow deve- lops, which causes the system to freeze out, thereby limiting the flow velocity in itself. This freeze-out dominance in turn makes a distinction between a plasma and a hadron resonance gas equation of state very difficult, whereas a pure pion gas can easily be ruled out from present data. To complete the picture we also analyze particle multiplicity data, which suggest that chemical equilibrium is not reached with respect to the strange particles. However, the over- population of pions seems to be at most moderate, with a pion chemical potential far away from the Bose divergence.Comment: 19 pages, 11 figs in separate uuencoded file, for LateX, epsf.tex, dvips, TPR-94-5 and BNL-(no number yet

Evaluation of minimal fracture liaison service resource : costs and survival in secondary fracture prevention-a prospective one-year study in South-Finland

Background Fracture liaison service (FLS) is a secondary prevention model for identification of patients at risk for fragility fractures. Aims This study was conducted to evaluate the number and costs of secondary prevention of low-energy fractures in the city of Kouvola in Finland. Methods Women aged >= 45 years and men >= 60 years treated in the emergency department with a low-energy fracture were identified. Laboratory testing, BMI, and DXA scans were performed. Fracture Risk Assessment Tool was used. The direct FLS costs were calculated. Survival was analyzed using univariate and multivariate analysis and the life-table method. Results 525 patients with 570 fractures were identified. The mean age of women was 73.8 years and of men 75.9 years. Most patients sustained wrist (31%), hip (21%) or proximal humerus (12%) fractures. 41.5% of the patients had osteoporosis according to DXA scans. 62% of patients used calcium and vitamin D daily and 38% started anti-osteoporotic medication. Protective factors for survival were: age <80 years, female sex, and S-25OHD concentration of 50-119 nmol/L. Excess mortality was highest among patients with a fracture of the femur. The total annual direct costs of FLS were 1.3% of the costs of all fractures. Discussion Many low-energy fracture types were associated with excess mortality. The use of anti-osteoporotic medication was not optimal. Conclusions FLS increased the catchment of low-energy fracture patients and was inexpensive. However, identification, evaluation and post-fracture assessment of patients should be expedited. Rehabilitation of hip fracture patients needs to be improved.Peer reviewe

Magneto-optical Kerr effect susceptometer for the analysis of magnetic domain wall dynamics

Domain wall dynamics in thin magnetic films with perpendicular and in-plane anisotropy is studied using a novel magneto-optical Kerr effect susceptometry method. The method allows for measurements of domain wall motion under ac field excitation and the analysis of dynamic modes as a function of driving frequency and magnetic field amplitude. Domain wall dynamics in the perpendicular anisotropy system, a Co/Pt multilayer, is characterized by thermally activated creep motion. For this dynamic mode, a polydispersivity exponent of β = 0.50 ± 0.03 is derived at small excitation energy, which is in excellent agreement with theoretical models. The dynamics of the other system, a Co wire with transverse uniaxial anisotropy, is dominated by viscous slide motion in a regular magnetic stripe pattern. Analytical expressions are derived for this magnetic configuration and by using these expressions, accurate values for the depinning field and the domain wall mobility are extracted from the susceptibility measurements.Peer reviewe

Guiding and reflecting light by boundary material

We study effects of finite height and surrounding material on photonic crystal slabs of one- and two-dimensional photonic crystals with a pseudo-spectral method and finite difference time domain simulation methods. The band gap is shown to be strongly modified by the boundary material. As an application we suggest reflection and guiding of light by patterning the material on top/below the slab.Comment: 12 pages, 7 figure

Rapidity Distributions of Dileptons from a Hadronizing Quark-Gluon Plasma

It has been predicted that dilepton production may be used as a quark-gluon plasma probe. We calculate the rapidity distributions of thermal dileptons produced by an evolving quark-gluon plasma assuming a longitudinal scaling expansion with initial conditions locally determined from the hadronic rapidity density. These distributions are compared with Drell-Yan production and semileptonic charm decays at invariant mass $M = 2$, 4, and 6 GeV.Comment: 17 pages (standard LaTeX), 6 figures (available as topdraw files or printed versions upon request), GSI-93-6

Thermal phenomenology of hadrons from 200 AGeV S+S collisions

We develop a complete and consistent description for the hadron spectra from heavy ion collisions in terms of a few collective variables, in particular temperature, longitudinal and transverse flow. To achieve a meaningful comparison with presently available data, we also include the resonance decays into our picture. To disentangle the influences of transverse flow and resonance decays in the $m_T$-spectra, we analyse in detail the shape of the $m_T$-spectra.Comment: 31 pages, 13 figs in seperate uuencoded file, for LaTeX, epsf.sty and dvips, TPR-93-16 and BNL-(no number yet