Thermal versus Direct J/ΨJ/\Psi Production in Ultrarelativistic Heavy-Ion Collisions

The production of $J/\Psi$ mesons in central collisions of heavy nuclei is investigated as a function of collision energy. Two contributions are considered simultaneously: early (hard) production coupled with subsequent suppression in a Quark-Gluon Plasma, as well as thermal recombination of primordially produced $c$ and $\bar c$ quarks at the hadronization transition. Whereas the former still constitutes the major fraction of the observed $J/\Psi$ abundance at SpS energies, the latter dominates the yield at RHIC. The resulting excitation function for the number of $J/\Psi$'s over open charm pairs exhibits nontrivial structure around $\sqrt{s} \simeq 30$ AGeV, evolving into a significant rise towards maximal RHIC energy. We study this feature within different (thermal) scenarios for $J/\Psi$ suppression, including parton-induced quasifree destruction as a novel mechanism.Comment: 6 pages ReVTeX, including 4 eps-figures; Revised version accepted for publication in Phys. Lett.

Theoretical Overview on (Hidden) Charm in High-Energy Heavy-Ion Collisions

Recent developments in the theoretical evaluation of charmonium production in ultrarelativistic heavy-ion collisions (URHIC's) are discussed. In particular, the consequences of equilibrium properties of open and hidden charm states -- accessible, {\it e.g.}, in QCD lattice gauge calculations -- are assessed. These include abundances as well as formation and dissociation rates of charmonia in both hadronic and quark-gluon matter.Comment: Invited Talk at 7. Int. Conf. on Strangeness in Quark Matter (Atlantic Beach, NC, USA, 12.-17.03.03); 10 pages LaTeX including 11 Figures and iop style files; v3: Section 3.4 (Continuity) revise

Two-Component Approach to J/ΨJ/\Psi Production in High-Energy Heavy-Ion Collisions

The production of charmonia in ultrarelativistic heavy-ion collisions is investigated including two sources. These are a primordial contribution coupled with various phases of dissociation, and a statistical coalescence of $c$ and $\bar{c}$ quarks at the hadronization phase transition. Within a schematic fireball evolution, SPS data on $J/\Psi$ production can be reasonably well reproduced. Remaining discrepancies in the $\Psi'/\Psi$ ratio are discussed. Predictions for the $J/\Psi$ centrality dependence at RHIC energies are confronted with first data from PHENIX. The pertinent excitation function of the $N_{J/\Psi}/N_{c\bar{c}}$ ratio exhibits a characteristic minimum structure signaling the transition from the standard $J/\Psi$ suppression scenario (SPS) to predominantly statistical production (RHIC).Comment: 4 pages (incl. 4 postscript figures); v2: Typos corrected; uses espcrc1.sty. Talk given at Quark Matter 2002, Nantes, July 18-24, 2002, to appear in the proceedings in Nucl. Phys.

Does a mandatory telemedicine call prior to visiting a physician reduce costs or simply attract good risks?

This paper aims to estimate empirically the efficiency of a Swiss telemedicine service introduced in 2003. We used claims' data gathered by a major Swiss health insurer, over a period of six years and involving 160 000 insured adults. In Switzerland, health insurance is mandatory, but everyone has the option of choosing between a managed care plan and a fee-for-service plan. The present paper focuses on a conventional fee-for-service plan including a mandatory access to a telemedicine service; the insured are obliged to phone this medical call centre prior to visiting a physician. This type of plan generates much lower average health expenditures than a conventional insurance plan. Reasons for this may include selection, incentive effects or simply efficiency. In our sample, about 90% of the difference in health expenditure can be explained by selection and incentive effects. The remaining 10% of savings due to the efficiency of the telemedicine service amount to about SFr 150 per year per insured, of which approx. 60% is saved by the insurer and 40% by the insured. While the plan is cost-effective, the big winners are the insured who not only save monetary and non-monetary costs, but also benefit from reduced premiums.health, insurance, selection, efficiency, telemedicine

Experimental Validation of Simplified Free Jet Turbulence Models Applied to the Vocal Tract

Sound production due to turbulence is widely shown to be an important phenomenon involved in a.o. fricatives, singing, whispering and speech pathologies. In spite of its relevance turbulent flow is not considered in classical physical speech production models mostly dealing with voiced sound production. The current study presents preliminary results of an experimental validation of simplified turbulence models in order to estimate the time-mean velocity distribution in a free jet downstream of a tube outlet. Aiming a future application in speech production the influence of typical vocal tract shape parameters on the velocity distribution is experimentally and theoretically explored: the tube shape, length and the degree and geometry of the constriction. Simplified theoretical predictions are obtained by applying similarity solutions of the bidimensional boundary layer theory to a plane and circular free jet in still air. The orifice velocity and shape are the main model input quantities. Results are discussed with respect to the upper airways and human sound production.Comment: 6 pages; 19th International Congress on Acoustics, Madrid : Espagne (2007

The Leadership of Ulysses S. Grant: A General Who Will Fight

A Look at the General Who Won the War Without a doubt he was the man who single handily won the war for the Union on the battlefield through his “uncommon drive and tenacity to not back down from a fight. General Ulysses S. Grant has been the study of hundreds of volumes in the past, b...

A Broken Regiment: The 16th Connecticut\u27s Civil War

War Without Glory: The Trials of the 16th Connecticut Late in the afternoon of September 17, 1862 a regiment of green Connecticut soldiers marched headlong into Otto’s Cornfield at Antietam. Forming part of the extreme left flank of the Army of the Potomac, the Nutmeggers, only days remove...

Separating selection and incentive effects in health insurance

This paper provides an analysis of the health insurance and health care consumption. A structural microeconomic model of joint demand for health insurance and health care is developed and estimated using full maximum likelihood method using Swiss insurance claims data for over 60 000 adult individuals. The estimation strategy relies on the institutional features of the Swiss system, in which each individual chooses among the same menu of contracts, ranked by the size of their deductible. The empirical analysis shows strong and robust evidence of selection effects. Nevertheless, once selection effects are controlled for, an important incentive effect ("ex-post moral hazard") remains. A decrease in the copayment rate from 100% to 10% increases the marginal demand for health care by about 90% and from 100% to 0% by about 150%. The correlation between insurance coverage and health care expenditures may be decomposed into the two effects: 75% may be attributed to selection, and 25 % to incentive effects.health insurance ; demand for health care ; moral hazard ; adverse selection ; full maximum likelihood estimation