11,480 research outputs found

    Testing the viability of the interacting holographic dark energy model by using combined observational constraints

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    Using the data coming from the new 182 Gold type Ia supernova samples, the shift parameter of the Cosmic Microwave Background given by the three-year Wilkinson Microwave Anisotropy Probe observations, and the baryon acoustic oscillation measurement from the Sloan Digital Sky Survey, H(z)H(z) and lookback time measurements, we have performed a statistical joint analysis of the interacting holographic dark energy model. Consistent parameter estimations show us that the interacting holographic dark energy model is a viable candidate to explain the observed acceleration of our universe.Comment: 15 pages, 9 figures, accepted for publication in JCA

    Depletion of pre-mRNA splicing factor Cdc5L inhibits mitotic progression and triggers mitotic catastrophe.

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    Disturbing mitotic progression via targeted anti-mitotic therapy is an attractive strategy for cancer treatment. Therefore, the exploration and elucidation of molecular targets and pathways in mitosis are critical for the development of anti-mitotic drugs. Here, we show that cell division cycle 5-like (Cdc5L), a pre-mRNA splicing factor, is a regulator of mitotic progression. Depletion of Cdc5L causes dramatic mitotic arrest, chromosome misalignments and sustained activation of spindle assembly checkpoint, eventually leading to mitotic catastrophe. Moreover, these defects result from severe impairment of kinetochore-microtubule attachment and serious DNA damage. Genome-wide gene expression analysis reveals that Cdc5L modulates the expression of a set of genes involved in the mitosis and the DNA damage response. We further found that the pre-mRNA splicing efficiency of these genes were impaired when Cdc5L was knocked down. Interestingly, Cdc5L is highly expressed in cervical tumors and osteosarcoma. Finally, we demonstrate that downregulation of Cdc5L decreases the cell viability of related tumor cells. These results suggest that Cdc5L is a key regulator of mitotic progression and highlight the potential of Cdc5L as a target for cancer therapy

    Interacting holographic dark energy model and generalized second law of thermodynamics in non-flat universe

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    In the present paper we consider the interacting holographic model of dark energy to investigate the validity of the generalized second laws of thermodynamics in non-flat (closed) universe enclosed by the event horizon measured from the sphere of the horizon named LL. We show that for LL as the system's IR cut-off the generalized second law is respected for the special range of the deceleration parameter.Comment: 11 pages, no figure

    Reconstructing the properties of dark energy from recent observations

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    We explore the properties of dark energy from recent observational data, including the Gold Sne Ia, the baryonic acoustic oscillation peak from SDSS, the CMB shift parameter from WMAP3, the X-ray gas mass fraction in cluster and the Hubble parameter versus redshift. The ΛCDM\Lambda CDM model with curvature and two parameterized dark energy models are studied. For the ΛCDM\Lambda CDM model, we find that the flat universe is consistent with observations at the 1σ1\sigma confidence level and a closed universe is slightly favored by these data. For two parameterized dark energy models, with the prior given on the present matter density, Ωm0\Omega_{m0}, with Ωm0=0.24\Omega_{m0}=0.24, Ωm0=0.28\Omega_{m0}=0.28 and Ωm0=0.32\Omega_{m0}=0.32, our result seems to suggest that the trend of Ωm0\Omega_{m0} dependence for an evolving dark energy from a combination of the observational data sets is model-dependent.Comment: 16 pages, 15 figures, To appear in JCA

    Holographic Dark Energy Scenario and Variable Modified Chaplygin Gas

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    In this letter, we have considered that the universe is filled with normal matter and variable modified Chaplygin gas. Also we have considered the interaction between normal matter and variable modified Chaplygin gas in FRW universe. Then we have considered a correspondence between the holographic dark energy density and interacting variable modified Chaplygin gas energy density. Then we have reconstructed the potential of the scalar field which describes the variable modified Chaplygin cosmology.Comment: 4 latex pages, no figures, RevTeX styl

    The Holographic Model of Dark Energy and Thermodynamics of Non-Flat Accelerated Expanding Universe

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    Motivated by recent results on non-vanishing spatial curvature \cite{curve} we employ the holographic model of dark energy to investigate the validity of first and second laws of thermodynamics in non-flat (closed) universe enclosed by apparent horizon RAR_A and the event horizon measured from the sphere of horizon named LL. We show that for the apparent horizon the first law is roughly respected for different epochs while the second laws of thermodynamics is respected while for LL as the system's IR cut-off first law is broken down and second law is respected for special range of deceleration parameter. It is also shown that at late-time universe LL is equal to RAR_A and the thermodynamic laws are hold, when the universe has non-vanishing curvature. Defining the fluid temperature to be proportional to horizon temperature the range for coefficient of proportionality is obtained provided that the generalized second law of thermodynamics is hold.Comment: 12 pages, no figure, abstract and text extended, references added, accepted for publication in JCA

    The DArk Matter Particle Explorer mission

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    The DArk Matter Particle Explorer (DAMPE), one of the four scientific space science missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences, is a general purpose high energy cosmic-ray and gamma-ray observatory, which was successfully launched on December 17th, 2015 from the Jiuquan Satellite Launch Center. The DAMPE scientific objectives include the study of galactic cosmic rays up to 10\sim 10 TeV and hundreds of TeV for electrons/gammas and nuclei respectively, and the search for dark matter signatures in their spectra. In this paper we illustrate the layout of the DAMPE instrument, and discuss the results of beam tests and calibrations performed on ground. Finally we present the expected performance in space and give an overview of the mission key scientific goals.Comment: 45 pages, including 29 figures and 6 tables. Published in Astropart. Phy

    Measurement of the branching fractions of psi(2S) -> 3(pi+pi-) and J/psi -> 2(pi+pi-)

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    Using data samples collected at sqrt(s) = 3.686GeV and 3.650GeV by the BESII detector at the BEPC, the branching fraction of psi(2S) -> 3(pi+pi-) is measured to be [4.83 +- 0.38(stat) +- 0.69(syst)] x 10^-4, and the relative branching fraction of J/psi -> 2(pi+pi-) to that of J/psi -> mu+mu- is measured to be [5.86 +- 0.19(stat) +- 0.39(syst)]% via psi(2S) -> (pi+pi-)J/psi, J/psi -> 2(pi+pi-). The electromagnetic form factor of 3(pi+pi-) is determined to be 0.21 +- 0.02 and 0.20 +- 0.01 at sqrt(s) = 3.686GeV and 3.650GeV, respectively.Comment: 17pages, 7 figures, submitted to Phys. Rev.
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