Intermittent emission of particles from three coupled condensates in a one-dimensional lattice

We investigate particle emission, driven by periodically modulating the interaction strength, from three coupled Bose-Einstein condensates in a one-dimensional lattice. Within perturbative analyses, which lead to the regimes of instabilities for different modes, we not only obtain two main frequencies, under which the system can emit a large particle jet, but also find that the emission is distinctly intermittent rather than continuous. The time evolution of the trapped particles exhibits a stair-like decay, and a larger drive induces a more significant intermittency. We further shed light on the dynamics of the stimulating process, and demonstrate that instead of a real suspension, the intermittency represents a build-up stage of the particles. The theoretical framework might be generalized, to the explorations on other multiple-condensate systems with analogous configurations and couplings.Comment: 7 pages, 10 figure

Dynamic Contrast-Enhanced Magnetic Resonance Imaging of Regional Nodal Metastasis in Nasopharyngeal Carcinoma: Correlation with Nodal Staging

published_or_final_versio

Intravoxel incoherent motion MR imaging in nasopharyngeal carcinoma: Comparison and correlation with dynamic contrast enhanced MR imaging

published_or_final_versio

Modification of membrane lipid peroxidation and antioxidant enzymes activation in transgenic rice resistant to Rhizoctonia solani

Activation of membrane lipid peroxidation and antioxidant enzymes were investigated in transgenic rice (Oryza sativa L.) lines J6 and J61 expressing the rice chitinase gene (RCH10) and the alfalfa â-1,3-glucanase gene (AGLU1). Our results show enhanced resistance of both lines to Rhizoctonia solani, the causal agent of rice sheath blight disease. While  malondialdehyde (MDA) was significantly generated with increasing  infection time, maximum production in wild-type (WT) transgenic lines J6 and J61 (44.35, 35.00 and 38.65 ìmol/g FW, respectively) occurred after 4 days. Analysis of superoxide dismutase (SOD) activity after 2 days inoculation also revealed distinct differences between WT (34.45 U/mg protein) and the 2 transgenic lines (J6; 45.86 U/mg protein; J61, 71.90 U/mg protein). On the other hand, the activities of catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) were found to be quite similar in all 3 lines. Taken together, these findings suggest that MDA content and SOD activity might play important roles in enhancing pathogen resistance in the transgenic plants. Our study provides a valuable route to analyze the mechanism of transgene-mediated defense in transgenic rice.Key words: Transgenic rice, resistance, sheath blight, Rhizoctonia solani, membrane lipid peroxidation, antioxidant enzymes

Quark Distributions of Octet Baryons from SU(3) Symmetry

SU(3) symmetry relations between the octet baryons are introduced in order to connect both the unpolarized and polarized quark distributions of the octet baryons with those of the nucleon. Two different parametrizations of the nucleon quark distributions are used. A new scenario of quark flavor and spin structure of the $\Lambda$ is found and compared with two other models: a perturbative QCD based analysis and a quark diquark model. The $u$ and $d$ quarks inside the $\Lambda$ are predicted to be positively polarized at large Bjorken variable $x$ in the new scenario. By using an approximate relation connecting the quark fragmentation functions with the quark distributions, the hadron polarizations of the octet baryons in $e^+e^-$-annihilation, polarized charged lepton deep inelastic scattering (DIS) processes, and neutrino (antineutrino) DIS processes are predicted. The predictions for $\Lambda$ polarizations in several processes are compatible with the available data at large fragmentation momentum fraction $z$, and support the prediction of positively polarized $u$ and $d$ quarks inside the $\Lambda$ at large $x$. Predictions for Drell-Yan processes from $\Sigma^{\pm}$ and $\Xi^-$ beams on an isoscalar target are also given and discussed.Comment: 29 latex pages, 16 figures, to appear in PR

Evidence for SU(3) symmetry breaking from hyperon production

We examine the SU(3) symmetry breaking in hyperon semileptonic decays (HSD) by considering two typical sets of quark contributions to the spin content of the octet baryons: Set-1 with SU(3) flavor symmetry and Set-2 with SU(3) flavor symmetry breaking in HSD. The quark distributions of the octet baryons are calculated with a successful statistical model. Using an approximate relation between the quark fragmentation functions and the quark distributions, we predict polarizations of the octet baryons produced in $e^+e^-$ annihilation and semi-inclusive deeply lepton-nucleon scattering in order to reveal the SU(3) symmetry breaking effect on the spin structure of the octet baryons. We find that the SU(3) symmetry breaking significantly affects the hyperon polarization. The available experimental data on the $\Lambda$ polarization seem to favor the theoretical predictions with SU(3) symmetry breaking. We conclude that there is a possibility to get a collateral evidence for SU(3) symmetry breaking from hyperon production. The theoretical errors for our predictions are discussed.Comment: 3 tables, 14 figure