1,577 research outputs found

    Position-Based Multi-Agent Dynamics for Real-Time Crowd Simulation (MiG paper)

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    Exploiting the efficiency and stability of Position-Based Dynamics (PBD), we introduce a novel crowd simulation method that runs at interactive rates for hundreds of thousands of agents. Our method enables the detailed modeling of per-agent behavior in a Lagrangian formulation. We model short-range and long-range collision avoidance to simulate both sparse and dense crowds. On the particles representing agents, we formulate a set of positional constraints that can be readily integrated into a standard PBD solver. We augment the tentative particle motions with planning velocities to determine the preferred velocities of agents, and project the positions onto the constraint manifold to eliminate colliding configurations. The local short-range interaction is represented with collision and frictional contact between agents, as in the discrete simulation of granular materials. We incorporate a cohesion model for modeling collective behaviors and propose a new constraint for dealing with potential future collisions. Our new method is suitable for use in interactive games.Comment: 9 page

    A single photon produces general W state of N qubits and its application

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    Based on the Wu's scheme[1], We prepare the general N-qubit W state. We find that the concurrence of two qubits in general N-qubit W state is only related to their coefficients and we successfully apply the general N-qubit W state to quantum state transfer and quantum state prepare like that in two-qubit system

    Carboplatin/taxane-induced gastrointestinal toxicity: a pharmacogenomics study on the SCOTROC1 trial

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    Carboplatin/taxane combination is first-line therapy for ovarian cancer. However, patients can encounter treatment delays, impaired quality of life, even death because of chemotherapy-induced gastrointestinal (GI) toxicity. A candidate gene study was conducted to assess potential association of genetic variants with GI toxicity in 808 patients who received carboplatin/taxane in the Scottish Randomized Trial in Ovarian Cancer 1 (SCOTROC1). Patients were randomized into discovery and validation cohorts consisting of 404 patients each. Clinical covariates and genetic variants associated with grade III/IV GI toxicity in discovery cohort were evaluated in replication cohort. Chemotherapy-induced GI toxicity was significantly associated with seven single-nucleotide polymorphisms in the ATP7B, GSR, VEGFA and SCN10A genes. Patients with risk genotypes were at 1.53 to 18.01 higher odds to develop carboplatin/taxane-induced GI toxicity (P<0.01). Variants in the VEGF gene were marginally associated with survival time. Our data provide potential targets for modulation/inhibition of GI toxicity in ovarian cancer patients

    Connected Green function approach to ground state symmetry breaking in Φ1+14\Phi^4_{1+1}-theory

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    Using the cluster expansions for n-point Green functions we derive a closed set of dynamical equations of motion for connected equal-time Green functions by neglecting all connected functions higher than 4th4^{th} order for the λΦ4\lambda \Phi^4-theory in 1+11+1 dimensions. We apply the equations to the investigation of spontaneous ground state symmetry breaking, i.e. to the evaluation of the effective potential at temperature T=0T=0. Within our momentum space discretization we obtain a second order phase transition (in agreement with the Simon-Griffith theorem) and a critical coupling of λcrit/4m2=2.446\lambda_{crit}/4m^2=2.446 as compared to a first order phase transition and λcrit/4m2=2.568\lambda_{crit}/4m^2=2.568 from the Gaussian effective potential approach.Comment: 25 Revtex pages, 5 figures available via fpt from the directory ugi-94-11 of [email protected] as one postscript file (there was a bug in our calculations, all numerical results and figures have changed significantly), ugi-94-1

    On Two-Body Decays of A Scalar Glueball

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    We study two body decays of a scalar glueball. We show that in QCD a spin-0 pure glueball (a state only with gluons) cannot decay into a pair of light quarks if chiral symmetry holds exactly, i.e., the decay amplitude is chirally suppressed. However, this chiral suppression does not materialize itself at the hadron level such as in decays into π+π\pi^+\pi^- and K+KK^+K^-, because in perturbative QCD the glueball couples to two (but not one) light quark pairs that hadronize to two mesons. Using QCD factorization based on an effective Lagrangian, we show that the difference of hadronization into ππ\pi\pi and KKKK already leads to a large difference between Br(π+π){\rm Br} (\pi^+\pi^-) and Br(K+K){\rm Br}(K^+K^-), even the decay amplitude is not chirally suppressed. Moreover, the small ratio of R=Br(ππ)/Br(KKˉ)R={\rm Br}(\pi\pi)/{\rm Br}(K\bar K) of f0(1710)f_0(1710) measured in experiment does not imply f0(1710)f_0(1710) to be a pure glueball. With our results it is helpful to understand the partonic contents if Br(ππ){\rm Br}(\pi\pi) or Br(KKˉ){\rm Br}(K\bar K) is measured reliably.Comment: revised versio

    Charmless Three-Body Baryonic B Decays

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    Motivated by recent data on B-> p pbar K decay, we study various charmless three-body baryonic B decay modes, including Lambda pbar pi, Sigma0 pbar pi, p pbar pi, p pbar Kbar0, in a factorization approach. These modes have rates of order 10^{-6}. There are two mechanisms for the baryon pair production, current-produced and transition. The behavior of decay spectra from these baryon production mechanisms can be understood by using QCD counting rules. Predictions on rates and decay spectra can be checked in the near future.Comment: 26 pages, 9 figures; version to appear in Phys. Rev.

    The CDF dijet excess from intrinsic quarks

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    The CDF collaboration reported an excess in the production of two jets in association with a WW. We discuss constraints on possible new particle state interpretations of this excess. The fact of no statistically significant deviation from the SM expectation for {ZZ+dijet} events in CDF data disfavors the new particle explanation. We show that the nucleon intrinsic strange quarks provide an important contribution to the WW boson production in association with a single top quark production. Such {WW+t} single top quark production can contribute to the CDF {WW+dijet} excess, thus the nucleon intrinsic quarks can provide a possible explanation to the CDF excess in {WW+dijet} but not in {ZZ+dijet} events.Comment: 4 latex pages, 1 figure. Version for journal publicatio

    Multigluon tree amplitudes with a pair of massive fermions

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    We consider the calculation of n-point multigluon tree amplitudes with a pair of massive fermions in QCD. We give the explicit transformation rules of this kind of massive fermion-pair amplitudes with respect to different reference momenta and check the correctness of them by SUSY Ward identities. Using these rules and onshell BCFW recursion relation, we calculate the analytic results of several n-point multigluon amplitudes.Comment: 15page
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