2,215 research outputs found

    Further evidence for a stiff nuclear equation of state from a transverse-momentum analysis of Ar(1800 MeV/nucleon) + KCl

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    The novel momentum analysis technique introduced by Danielewicz and Odyniec can be used to detect and exhibit collective flow in the light system Ar(1800 MeV/nucleon) + KCl where the usual kinetic energy flow analysis fails. The microscopic Vlasov-Uehling-Uhlenbeck theory which includes the nuclear mean field, two-body collisions, and Pauli blocking is used to study this phenomenon. The resulting transverse momentum transfers turn out to be quite sensitive to the nuclear equation of state. From a comparison with experimental data, evidence is presented for a rather stiff nuclear equation of state. The cascade model is unable to describe the data

    Evolution of 4 pi observables in the Vlasov-Uehling-Uhlenbeck theory and the transverse momentum transfer as a barometer for hadronic matter

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    We study the dynamics of high energy heavy ion collisions through the Vlasov-Uehling-Uhlenbeck approach. Equilibration is observed, for central collisions. It is shown that the produced entropy, the pion multiplicity, flow angle, and transverse momentum distributions saturate at the moment of maximum compression and temperature. The effects of the nuclear equation of state and the Pauli principle are investigated. For the flow angle distribution there is a 20 deg reduction of the peak flow angle due to the Pauli principle. A stiff equation of state results in a 10–20 deg increase over the soft equation of state at all energies. The transverse momentum at projectile rapidity exhibits a peak structure as a function of impact parameter b. A 40% difference between soft and hard equation of state is observed for the peak impact parameter, i.e., for intermediate multiplicities

    Intranuclear cascade models lack dynamic flow

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    We study the recent claim that the intranuclear cascade model exhibits collective sidewards flow. 4000 intranuclear cascade simulations of the reaction Nb(400 MeV/nucleon)+Nb are performed employing bound and unbound versions of the Cugnon cascade. We show that instability of the target and projectile nuclei in the unbound cascade produces substantial spurious sidewards flow angles, for spectators as well as for participants. Once the nuclear binding is included, the peak of the flow angle distributions for the participants alone is reduced from 35° to 17°. The theoretical ‘‘data’’ are subjected to the experimental multiplicity and efficiency cuts of the plastic ball 4π electronic spectrometer system. The flow angular distributions obtained from the bound cascade—with spectators and participants subjected to the plastic ball filter—are forward peaked, in contrast to the plastic ball data. We discuss the uncertainties encountered with the application of the experimental efficiency and multiplicity filter. The influence of the Pauli principle on the flow is also discussed. The lack of flow effects in the cascade model clearly reflects the absence of the nuclear compression energy that can cause substantially larger collective sidewards motion—there is too little intrinsic pressure built up in the cascade model

    Therapeutic translation in acute kidney injury: the epithelial/endothelial axis

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    Acute kidney injury (AKI) remains a major clinical event with rising incidence, severity, and cost; it now has a morbidity and mortality exceeding acute myocardial infarction. There is also a documented conversion to and acceleration of chronic kidney disease to end-stage renal disease. The multifactorial nature of AKI etiologies and pathophysiology and the lack of diagnostic techniques have hindered translation of preclinical success. An evolving understanding of epithelial, endothelial, and inflammatory cell interactions and individualization of care will result in the eventual development of effective therapeutic strategies. This review focuses on epithelial and endothelial injury mediators, interactions, and targets for therapy

    Microscopic calculations of collective flow probing the short-range nature of the nuclear force

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    Collisions between two nuclei have been modeled by numerical solution of classical approximations to the equations of motion of the constituent nucleons. For the reaction Nb(400 MeV/u)+Nb, a correlated sidewards emission of nucleons is observed. This is attributed to the repulsive short-range component of the nucleon-nucleon potential. A strong dependence of the flow angle on the impact parameter is observed, in accord with recent experimental results
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