4,163 research outputs found

    Statefinder hierarchy exploration of the extended Ricci dark energy

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    We apply the statefinder hierarchy plus the fractional growth parameter to explore the extended Ricci dark energy (ERDE) model, in which there are two independent coefficients α\alpha and β\beta. By adjusting them, we plot evolution trajectories of some typical parameters, including Hubble expansion rate EE, deceleration parameter qq, the third and fourth order hierarchy S3(1)S_3^{(1)} and S4(1)S_4^{(1)} and fractional growth parameter ϵ\epsilon, respectively, as well as several combinations of them. For the case of variable α\alpha and constant β\beta, in the low-redshift region the evolution trajectories of EE are in high degeneracy and that of qq separate somewhat. However, the Λ\LambdaCDM model is confounded with ERDE in both of these two cases. S3(1)S_3^{(1)} and S4(1)S_4^{(1)}, especially the former, perform much better. They can differentiate well only varieties of cases within ERDE except Λ\LambdaCDM in the low-redshift region. For high-redshift region, combinations {Sn(1),ϵ}\{S_n^{(1)},\epsilon\} can break the degeneracy. Both of {S3(1),ϵ}\{S_3^{(1)},\epsilon\} and {S4(1),ϵ}\{S_4^{(1)},\epsilon\} have the ability to discriminate ERDE with α=1\alpha=1 from Λ\LambdaCDM, of which the degeneracy cannot be broken by all the before-mentioned parameters. For the case of variable β\beta and constant α\alpha, S3(1)(z)S_3^{(1)}(z) and S4(1)(z)S_4^{(1)}(z) can only discriminate ERDE from Λ\LambdaCDM. Nothing but pairs {S3(1),ϵ}\{S_3^{(1)},\epsilon\} and {S4(1),ϵ}\{S_4^{(1)},\epsilon\} can discriminate not only within ERDE but also ERDE from Λ\LambdaCDM. Finally we find that S3(1)S_3^{(1)} is surprisingly a better choice to discriminate within ERDE itself, and ERDE from Λ\LambdaCDM as well, rather than S4(1)S_4^{(1)}.Comment: 8 pages, 14 figures; published versio

    SU(5) Symmetry of spdfg Interacting Boson Model

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    The extended interacting boson model with s-, p-, d-, f- and g-bosons being included (spdfg IBM) are investigated. The algebraic structure including the generators, the Casimir operators of the groups at the SU(5) dynamical symmetry and the branching rules of the irreducible representation reductions along the group chain are obtained. The typical energy spectrum of the Symmetry is given.Comment: 12 pages, 2 figure

    Two Photon Transition Form Factor of cˉc\bar{c}c Quarkonia

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    The two photon transition of cˉc\bar{c}c quarkonia are studied within a covariant approach based on the consistent truncation scheme of the quantum chromodynamics Dyson-Schwinger equation for the quark propagator and the Bethe--Salpeter equation for the mesons. We find the decay widths of ηc→γγ\eta_{c}^{} \to \gamma\gamma and χc0,2→γγ\chi_{c0,2}^{} \to \gamma\gamma in good agreement with experimental data. The obtained transition form factor of ηc→γγ∗\eta_{c}^{} \to \gamma\gamma^{\ast} for a wide range of space-like photon momentum transfer squared is also in agreement with the experimental findings of the BABAR experiment. As a by-product, the decay widths of ηb,χb0,2→γγ\eta_{b}^{},\chi_{b0,2}^{} \to \gamma\gamma and the transition form factor of ηb,χc0,b0→γγ∗\eta_{b}^{}, \chi_{c0,b0}^{} \to\gamma\gamma^{\ast} are predicted, which await for experimental test

    Genetically engineered pre-microRNA-34a prodrug suppresses orthotopic osteosarcoma xenograft tumor growth via the induction of apoptosis and cell cycle arrest.

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    Osteosarcoma (OS) is the most common primary malignant bone tumor in children, and microRNA-34a (miR-34a) replacement therapy represents a new treatment strategy. This study was to define the effectiveness and safety profiles of a novel bioengineered miR-34a prodrug in orthotopic OS xenograft tumor mouse model. Highly purified pre-miR-34a prodrug significantly inhibited the proliferation of human 143B and MG-63 cells in a dose dependent manner and to much greater degrees than controls, which was attributed to induction of apoptosis and G2 cell cycle arrest. Inhibition of OS cell growth and invasion were associated with release of high levels of mature miR-34a from pre-miR-34a prodrug and consequently reduction of protein levels of many miR-34a target genes including SIRT1, BCL2, c-MET, and CDK6. Furthermore, intravenous administration of in vivo-jetPEI formulated miR-34a prodrug significantly reduced OS tumor growth in orthotopic xenograft mouse models. In addition, mouse blood chemistry profiles indicated that therapeutic doses of bioengineered miR-34a prodrug were well tolerated in these animals. The results demonstrated that bioengineered miR-34a prodrug was effective to control OS tumor growth which involved the induction of apoptosis and cell cycle arrest, supporting the development of bioengineered RNAs as a novel class of large molecule therapeutic agents

    Band renormalization and Fermi surface reconstruction in iron-based superconductors

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    Using the fluctuation exchange approximation and a three-orbital model, we study the band renormalization, Fermi surface reconstruction and the superconducting pairing symmetry in the newly-discovered iron-based superconductors. We find that the inter-orbital spin fluctuations lead to the strong anisotropic band renormalization and the renormalization is orbital dependent. As a result, the topology of Fermi surface displays distinct variation with doping from the electron type to the hole type, which is consistent with the recent experiments. This shows that the Coulomb interactions will have a strong effect on the band renormalization and the topology of the electron Fermi pocket. In addition, the pairing state mediated by the inter-orbital spin fluctuation is of an extended s-wave symmetry.Comment: 16 pages, 6 figure

    Phase diagram and thermal properties of strong-interaction matter

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    We introduce a novel procedure for computing the (mu,T)-dependent pressure in continuum QCD; and therefrom obtain a complex phase diagram and predictions for thermal properties of the system, providing the in-medium behaviour of the trace anomaly, speed of sound, latent heat and heat capacity.Comment: 6 pages, 4 figures. Minor amendments in the version accepted for publicatio
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