7,712 research outputs found

    Non-canonical statistics of finite quantum system

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    The canonical statistics describes the statistical properties of an open system by assuming its coupling with the heat bath infinitesimal in comparison with the total energy in thermodynamic limit. In this paper, we generally derive a non-canonical distribution for the open system with a finite coupling to the heat bath, which deforms the energy shell to effectively modify the conventional canonical way. The obtained non-canonical distribution reflects the back action of system on the bath, and thus depicts the statistical correlations through energy fluctuations

    Valosin-containing protein regulates the proteasome-mediated degradation of DNA-PKcs in glioma cells.

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    DNA-dependent protein kinase (DNA-PK) has an important role in the repair of DNA damage and regulates the radiation sensitivity of glioblastoma cells. The VCP (valosine-containing protein), a chaperone protein that regulates ubiquitin-dependent protein degradation, is phosphorylated by DNA-PK and recruited to DNA double-strand break sites to regulate DNA damage repair. However, it is not clear whether VCP is involved in DNA-PKcs (DNA-PK catalytic subunit) degradation or whether it regulates the radiosensitivity of glioblastoma. Our data demonstrated that DNA-PKcs was ubiquitinated and bound to VCP. VCP knockdown resulted in the accumulation of the DNA-PKcs protein in glioblastoma cells, and the proteasome inhibitor MG132 synergised this increase. As expected, this increase promoted the efficiency of DNA repair in several glioblastoma cell lines; in turn, this enhanced activity decreased the radiation sensitivity and prolonged the survival fraction of glioblastoma cells in vitro. Moreover, the VCP knockdown in glioblastoma cells reduced the survival time of the xenografted mice with radiation treatment relative to the control xenografted glioblastoma mice. In addition, the VCP protein was also downregulated in ~25% of GBM tissues from patients (WHO, grade IV astrocytoma), and the VCP protein level was correlated with patient survival (R(2)=0.5222, P<0.05). These findings demonstrated that VCP regulates DNA-PKcs degradation and increases the sensitivity of GBM cells to radiation

    Non-Abelian Medium Effects in Quark-Gluon Plasma

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    Based on the kinetic theory, the non-Abelian medium property of hot Quark-Gluon Plasma is investigated. The nonlinearity of the plasma comes from two aspects: The nonlinear wave-wave interaction and self-interaction of color field. The non-Abelian color permittivity is obtained by expanding the kinetic equations to third order. As an application, the nonlinear Landau damping rate and the nonlinear eigenfrequency shift are calculated in the longwave length limit.Comment: 12 pages(Revtex), no figure

    To eat like Liangzhu: isotopic investigation of diets in the Lower Yangtze area prior to and during the Liangzhu period (5300–4300 cal. BP)

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    \ua9 The Author(s) 2024.This essay analyzes a robust body of C and N stable isotopes from human and animal collagen and plant remains (n = 423) in the area of Lower Yangtze River dating to 8000–4300 cal. BP, combined with new isotopic data recovered from the Zhelin site in Shanghai, to explore the dietary differences between coastal region and the inland core area of the Liangzhu culture (5300–4300 cal. BP). Our findings suggest that the food variety of the peripheral inhabitants of the core area of the Liangzhu culture may became less diverse over time, while at the same time their reliance on a few domesticated species (rice and pigs) increased. It may be a result of the growing economic and cultural influence of the populations in the inland core Liangzhu area

    Bs0→η(′)η(′)B_s^0 \to \eta^{(\prime)} \eta^{(\prime)} decays in the pQCD approach

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    We calculate the CP averaged branching ratios and CP-violating asymmetries for Bs0→ηη,ηη′B_s^0 \to \eta \eta, \eta \eta^\prime and η′η′\eta^\prime \eta^\prime decays in the perturbative QCD (pQCD) approach here. The pQCD predictions for the CP-averaged branching ratios are Br(B_s^0 \to \eta \eta) = \left (14.2^{+18.0}_{-7.5}) \times 10^{-6}, Br(B_s^0 \to \eta \eta^\prime)= \left (12.4 ^{+18.2}_{-7.0}) \times 10^{-6}, and Br(B_s^0 \to \eta^{\prime} \eta^{\prime}) = \left (9.2^{+15.3}_{-4.9}) \times 10^{-6}, which agree well with those obtained by employing the QCD factorization approach and also be consistent with available experimental upper limits. The gluonic contributions are small in size: less than 7% for Bs→ηηB_s \to \eta \eta and ηη′ \eta \eta^\prime decays, and around 18% for Bs→η′η′B_s \to \eta' \eta' decay. The CP-violating asymmetries for three decays are very small: less than 3% in magnitude.Comment: 11 pages, 1 ps figure, Revte

    Negative Magnetoresistance in the Nearest-neighbor Hopping Conduction

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    We propose a size effect which leads to the negative magnetoresistance in granular metal-insulator materials in which the hopping between two nearest neighbor clusters is the main transport mechanism. We show that the hopping probability increases with magnetic field. This is originated from the level crossing in a few-electron cluster. Thus, the overlap of electronic states of two neighboring clusters increases, and the negative magnetoresistance is resulted.Comment: Latex file, no figur

    Exotic Gapless Mott Insulators of Bosons on Multi-Leg Ladders

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    We present evidence for an exotic gapless insulating phase of hard-core bosons on multi-leg ladders with a density commensurate with the number of legs. In particular, we study in detail a model of bosons moving with direct hopping and frustrating ring exchange on a 3-leg ladder at ν=1/3\nu=1/3 filling. For sufficiently large ring exchange, the system is insulating along the ladder but has two gapless modes and power law transverse density correlations at incommensurate wave vectors. We propose a determinantal wave function for this phase and find excellent comparison between variational Monte Carlo and density matrix renormalization group calculations on the model Hamiltonian, thus providing strong evidence for the existence of this exotic phase. Finally, we discuss extensions of our results to other NN-leg systems and to NN-layer two-dimensional structures.Comment: 5 pages, 4 figures; v3 is the print version; supplemental material attache
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