3,392 research outputs found
Observational constraint on the interacting dark energy models including the Sandage-Loeb test
Two types of interacting dark energy models are investigated using the type
Ia supernova (SNIa), observational data (OHD), cosmic microwave
background (CMB) shift parameter and the secular Sandage-Loeb (SL) test. We
find that the inclusion of SL test can obviously provide more stringent
constraint on the parameters in both models. For the constant coupling model,
the interaction term including the SL test is estimated at , which has been improved to be only a half
of original scale on corresponding errors. Comparing with the combination of
SNIa and OHD, we find that the inclusion of SL test directly reduces the
best-fit of interaction from 0.39 to 0.10, which indicates that the
higher-redshift observation including the SL test is necessary to track the
evolution of interaction. For the varying coupling model, we reconstruct the
interaction , and find that the interaction is also negative
similar as the constant coupling model. However, for high redshift, the
interaction generally vanishes at infinity. The constraint result also shows
that the CDM model still behaves a good fit to the observational data,
and the coincidence problem is still quite severe. However, the phantom-like
dark energy with is slightly favored over the CDM model.Comment: 10 pages, 7 figure
Synthetic Topological Degeneracy by Anyon Condensation
Topological degeneracy is the degeneracy of the ground states in a many-body
system in the large-system-size limit. Topological degeneracy cannot be lifted
by any local perturbation of the Hamiltonian. The topological degeneracies on
closed manifolds have been used to discover/define topological order in
many-body systems, which contain excitations with fractional statistics. In
this paper, we study a new type of topological degeneracy induced by condensing
anyons along a line in 2D topological ordered states. Such topological
degeneracy can be viewed as carried by each end of the line-defect, which is a
generalization of Majorana zero-modes. The topological degeneracy can be used
as a quantum memory. The ends of line-defects carry projective non-Abelian
statistics, and braiding them allow us to perform fault tolerant quantum
computations.Comment: 4 pages + references + 3 pages of supplementary material, 2 figures.
reference update
Cyclin B1/Cdk1 phosphorylation of mitochondrial p53 induces anti-apoptotic response.
The pro-apoptotic function of p53 has been well defined in preventing genomic instability and cell transformation. However, the intriguing fact that p53 contributes to a pro-survival advantage of tumor cells under DNA damage conditions raises a critical question in radiation therapy for the 50% human cancers with intact p53 function. Herein, we reveal an anti-apoptotic role of mitochondrial p53 regulated by the cell cycle complex cyclin B1/Cdk1 in irradiated human colon cancer HCT116 cells with p53(+/+) status. Steady-state levels of p53 and cyclin B1/Cdk1 were identified in the mitochondria of many human and mouse cells, and their mitochondrial influx was significantly enhanced by radiation. The mitochondrial kinase activity of cyclin B1/Cdk1 was found to specifically phosphorylate p53 at Ser-315 residue, leading to enhanced mitochondrial ATP production and reduced mitochondrial apoptosis. The improved mitochondrial function can be blocked by transfection of mutant p53 Ser-315-Ala, or by siRNA knockdown of cyclin B1 and Cdk1 genes. Enforced translocation of cyclin B1 and Cdk1 into mitochondria with a mitochondrial-targeting-peptide increased levels of Ser-315 phosphorylation on mitochondrial p53, improved ATP production and decreased apoptosis by sequestering p53 from binding to Bcl-2 and Bcl-xL. Furthermore, reconstitution of wild-type p53 in p53-deficient HCT116 p53(-/-) cells resulted in an increased mitochondrial ATP production and suppression of apoptosis. Such phenomena were absent in the p53-deficient HCT116 p53(-/-) cells reconstituted with the mutant p53. These results demonstrate a unique anti-apoptotic function of mitochondrial p53 regulated by cyclin B1/Cdk1-mediated Ser-315 phosphorylation in p53-wild-type tumor cells, which may provide insights for improving the efficacy of anti-cancer therapy, especially for tumors that retain p53
Study on Earthquake-Induced Permanent Deformation of Earth-Rockfill Dams
Based on the experimental data, a three-dimensional (3-D) nonlinear effective stress seismic response analysis method of earth-rockfill dams is proposed with the dissipation and diffusion of seismic pore-water pressure been considered. Then a method for evaluating the earthquake-induced permanent deformation of earth-rockfill dams taking into account both residual shear strain and residual volumetric strain is presented. The method proposed by Taniguchi is adopted to evaluate the earthquake-induced permanent deformation caused by residual shear strain. In order to evaluate the earthquake-induced permanent deformation caused by residual volumetric strain, the saturated part and the non-saturated part of the dams are treated separately. An expression of residual volumetric strain for non-saturated soils is proposed by analyzing the test data. As an example, the evaluation of the earthquake-induced permanent deformation of Zipingpu dam is performed
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