Excitation function of nucleon and pion elliptic flow in relativistic heavy-ion collisions

Within a relativistic transport (ART) model for heavy-ion collisions, we show that the recently observed characteristic change from out-of-plane to in-plane elliptic flow of protons in mid-central Au+Au collisions as the incident energy increases is consistent with the calculated results using a stiff nuclear equation of state (K=380 MeV). We have also studied the elliptic flow of pions and the transverse momentum dependence of both the nucleon and pion elliptic flow in order to gain further insight about the collision dynamics.Comment: 8 pages, 2 figure

On quantum vertex algebras and their modules

We give a survey on the developments in a certain theory of quantum vertex algebras, including a conceptual construction of quantum vertex algebras and their modules and a connection of double Yangians and Zamolodchikov-Faddeev algebras with quantum vertex algebras.Comment: 18 pages; contribution to the proceedings of the conference in honor of Professor Geoffrey Maso

Separation of suspended particles by arrays of obstacles in microfluidic devices

The stochastic transport of suspended particles through a periodic pattern of obstacles in microfluidic devices is investigated by means of the Fokker-Planck equation. Asymmetric arrays of obstacles have been shown to induce the continuous separation of DNA molecules of different length. The analysis presented here of the asymptotic distribution of particles in a unit cell of these systems shows that separation is only possible in the presence of a driving force with a non-vanishing normal component at the surface of the solid obstacles. In addition, vector separation, in which different species move, in average, in different directions within the device, is driven by differences on the force acting on the various particles and not by differences in the diffusion coefficient. Monte-Carlo simulations performed for different particles and force fields agree with the numerical solutions of the Fokker-Planck equation in the periodic system

τ→ρππν\tau\to\rho\pi\pi\nu decays

Effective chiral theory of mesons is applied to study the four decay modes of $\tau\to\rho\pi\pi\nu$. Theoretical values of the branching ratios are in agreement with the data. The theory predicts that the $a_{1}$ resonance plays a dominant role in these decays. There is no new parameter in this study.Comment: 12 pages and one figur

Effective video multicast over wireless internet

With the rapid growth of wireless networks and great success of Internet video, wireless video services are expected to be widely deployed in the near future. As different types of wireless networks are converging into all IP networks, i.e., the Internet, it is important to study video delivery over the wireless Internet. This paper proposes a novel end-system based adaptation protocol calledWireless Hybrid Adaptation Layered Multicast (WHALM) protocol for layered video multicast over wireless Internet. In WHALM the sender dynamically collects bandwidth distribution from the receivers and uses an optimal layer rate allocation mechanism to reduce the mismatches between the coarse-grained layer subscription levels and the heterogeneous and dynamic rate requirements from the receivers, thus maximizing the degree of satisfaction of all the receivers in a multicast session. Based on sampling theory and theory of probability, we reduce the required number of bandwidth feedbacks to a reasonable degree and use a scalable feedback mechanism to control the feedback process practically. WHALM is also tuned to perform well in wireless networks by integrating an end-to-end loss differentiation algorithm (LDA) to differentiate error losses from congestion losses at the receiver side. With a series of simulation experiments over NS platform, WHALM has been proved to be able to greatly improve the degree of satisfaction of all the receivers while avoiding congestion collapse on the wireless Internet

Self-similarity in a system with short-time delayed feedback

Using the Poincar\'{e} section technique, we study in detail the dynamical behaviors of delay differential system and find a new type of solutions $S_i$ in short-time delay feedback. Our numerical results remind us to deny the opinion that there are no complex phenomena in short-time delay case. Many similarities between foundamental solution and the new type of solutions are found. We demonstrate that the scales of $S_i$ increase with exponential growth via $i$ in the direction of $\mu$, while decrease with exponential decays in the direction of $x$ or delay time $t_R$.Comment: 4 pages, REVTEX, 4 ps figures, to be published in Phys. Lett.