Isospin Diffusion and Equilibration for Sn+Sn collisions at E/A=35 MeV

Equilibration and equilibration rates have been measured by colliding Sn nuclei with different isospin asymmetries at beam energies of E/A=35 MeV. Using the yields of mirror nuclei of 7Li and 7Be, we have studied the diffusion of isospin asymmetry by combining data from asymmetric 112Sn+124Sn and 124Sn+112Sn collisions with that from symmetric 112Sn+112Sn and 124Sn+124Sn collisions. We use these measurements to probe isospin equilibration in central collisions where nucleon-nucleon collisions are strongly blocked by the Pauli exclusion principal. The results are consistent with transport theoretical calculations that predict a degree of transparency in these collisions, but inconsistent with the emission of intermediate mass fragments by a single chemically equilibrated source. Comparisons with ImQMD calculations are consistent with results obtained at higher incident energies that provide constraints on the density dependence of the symmetry energy.Comment: 13 pages, 3 figures, submitted to PRC Rapid Communication

SystemC simulation on GP-GPUs: CUDA vs. OpenCL

SystemC is a widespread language for developing SoC designs. %Unfortunately, its simulation performance is heavily affected by a strictly sequential scheduler that slows down verification and time-to-market for new designs. Unfortunately, most SystemC simulators are based on a strictly sequential scheduler that heavily limits their performance, impacting verification schedules and time-to-market of new designs. Parallelizing SystemC simulation %requires a thorough entails a complete re-design of the simulator kernel for the specific target parallel architectures. This paper proposes an automatic methodology to generate a parallel SystemC simulator kernel, exploiting the massive parallelism of GP-GPU architectures. Our solution leverages static scheduling to reduce synchronization overheads. The generated simulator code targets both \cuda\ and \opencl\ libraries, to boost scalability and provide support for multiple GP-GPU architectures. % We find experimentally that we achieve a compression of simulation time by one order of magnitude on these targets. Finally, the paper compares the performance of our solution on \cuda\ vs. \opencl\ platforms, with the goal of investigating advantages and drawbacks that the two thread management libraries offer to concurrent SystemC simulation

Competition for co-operation: Roles and Realities in Russian Foreign Policy

The discursive reconstruction of Eurasia has brought about structural changes, which have strengthened Russia’s position internationally, and fortified its soft power. As such, the Eurasian project reflects Russia’s broader approach to parties including BRICS and the EU. Russia’s political elite routinely promotes specific conceptions of Russia’s international identity and role with different partners as a means to facilitate cooperation. This creates significant geographical and policy overlaps and breeds inconsistency and competition, but nonetheless contributes to Russia’s preferred low-cost, low-commitment version of co-operation. The Eurasian project therefore represents just one (albeit important) example of the Russian leadership’s conversion of ideas about the international arena into political realities. By balancing competing roles and relationships, Russia maintains a ‘multi-vector’ foreign policy that is flexible, unencumbered by restrictive alliances, and oriented towards sovereignty, great power and strength

CONSTRAINTS ON THE DENSITY DEPENDENCE OF THE SYMMETRY ENERGY

Collisions involving Sn-112 and Sn-124 nuclei have been calculated with the ImQMD transport model in order to place constraints on the density dependences of the nuclear symmetry energy. Consistent constraints on the symmetry energy at sub-saturation density have been obtained by comparing these transport calculations to measurements of isospin diffusion and to the ratios of neutron and proton spectra. New isospin diffusion results from E/A = 35 MeV are also presented

Probing the equation of state of asymmetric nuclear matter with isospin diffusion and stopping in heavy-ion collisions

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