237 research outputs found

    Curvature perturbation at the local extremum of the inflaton's potential

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    The spectrum of curvature perturbation generated during inflation is studied in the case the inflation-driving scalar field (inflaton) ϕ\phi crosses over its potential extremum. It is shown that the nondecaying mode of perturbation has a finite value and a proper formula is given. The result is also extended to more general cases where ϕ¨\ddot{\phi} is non-negligible.Comment: 6 pages, 1 figure. To appear in Physics Letters

    A Lightweight Visualization of Interprocedural Data-Flow Paths for Source Code Reading

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    Program Comprehension (ICPC), 2012 IEEE 20th International Conference onDate of Conference:11-13 June 2012Conference Location :Passa

    ヒト骨髄由来CD133陽性細胞移植とアルギン酸ゲルシートを用いた新たなラット陰茎再生

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    審査の要旨 , 内容の要旨広島大学(Hiroshima University)博士(医学)Doctor of Philosophy in Medical Sciencedoctora

    CADLIVE Optimizer: Web-based Parameter Estimation for Dynamic Models

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    Computer simulation has been an important technique to capture the dynamics of biochemical networks. In most networks, however, few kinetic parameters have been measured in vivo because of experimental complexity. We develop a kinetic parameter estimation system, named the CADLIVE Optimizer, which comprises genetic algorithms-based solvers with a graphical user interface. This optimizer is integrated into the CADLIVE Dynamic Simulator to attain efficient simulation for dynamic models

    CADLIVE optimizer: web-based parameter estimation for dynamic models

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    Computer simulation has been an important technique to capture the dynamics of biochemical networks. In most networks, however, few kinetic parameters have been measured in vivo because of experimental complexity. We develop a kinetic parameter estimation system, named the CADLIVE Optimizer, which comprises genetic algorithms-based solvers with a graphical user interface. This optimizer is integrated into the CADLIVE Dynamic Simulator to attain efficient simulation for dynamic models

    Decomposing the Spectrum of Ultra-Luminous X-ray Pulsar NGC 300 ULX-1

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    A phase-resolved analysis on the X-ray spectrum of Ultra-Luminous X-ray Pulsar (ULXP) NGC 300 ULX-1 is performed with data taken with XMM-Newton and NuSTAR on 2016 December 16th. In addition to the classical phase-restricting analysis, a method developed in active galactic nuclei studies is newly employed for ULXP. It has revealed that the pulsation cycle of the source can be divided into two intervals in terms of X-ray variability. This suggests the rotating flow consists of at least two representative emission regions. Furthermore, the new method successfully decomposed the spectrum into an independent pair in each interval. One is an unchanging-component spectrum that can be reproduced by a standard disk model with a 720120+220720^{+220}_{-120} km inner radius and a 0.25±0.030.25\pm0.03 keV peak temperature. The other is the spectrum of the component that coincides with the pulsation. This was explained with a Comptonization of a 0.220.1+0.20.22^{+0.2}_{-0.1} keV blackbody and exhibited a harder photon index in the brighter phase interval of two. The results are consistent with a picture that the pulsating emission originates from a funnel-like flow formed within the magnetosphere, and the inner flow exhibiting a harder continuum is observed exclusively when the opening cone points to the observer.Comment: 27 pages, 15 figures, accepted for publication in Ap

    Embryonic Development following Somatic Cell Nuclear Transfer Impeded by Persisting Histone Methylation

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    Mammalian oocytes can reprogram somatic cells into a totipotent state enabling animal cloning through somatic cell nuclear transfer (SCNT). However, the majority of SCNT embryos fail to develop to term due to undefined reprogramming defects. Here we identify histone H3 lysine 9 trimethylation (H3K9me3) of donor cell genome as a major epigenetic barrier for efficient reprogramming by SCNT. Comparative transcriptome analysis identified reprogramming resistant regions (RRRs) that are expressed normally at 2-cell mouse embryos generated by IVF but not SCNT. RRRs are enriched for H3K9me3 in donor somatic cells, and its removal by ectopic expression of the H3K9me3 demethylase Kdm4d not only reactivates the majority of RRRs, but also greatly improves SCNT efficiency. Furthermore, use of donor somatic nuclei depleted of H3K9 methyltransferases markedly improves SCNT efficiency. Our study thus identifies H3K9me3 as a critical epigenetic barrier in SCNT-mediated reprogramming and provides a promising approach for improving mammalian cloning efficiency

    Haploinsufficiency, but Not Defective Paternal 5mC Oxidation, Accounts for the Developmental Defects of Maternal Tet3 Knockouts

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    Paternal DNA demethylation in mammalian zygotes is achieved through Tet3-mediated iterative oxidation of 5-methylcytosine (5mC) coupled with replication-dependent dilution. Tet3-mediated paternal DNA demethylation is believed to play important roles in mouse development given that Tet3 heterozygous embryos derived from Tet3-deficient oocytes exhibit embryonic sublethality. Here, we demonstrate that the sublethality phenotype of the Tet3 maternal knockout mice is caused by haploinsufficiency but not defective paternal 5mC oxidation. We found that Tet3 heterozygous progenies derived from heterozygous father or mother also exhibit sublethality. Importantly, wild-type embryos reconstituted with paternal pronuclei that bypassed 5mC oxidation develop and grow to adulthood normally. Genome-scale DNA methylation analysis demonstrated that hypermethylation in maternal Tet3 knockout embryos is largely diminished by the blastocyst stage. Our study thus reveals that Tet3-mediated paternal 5mC oxidation is dispensable for mouse development and suggests the existence of a compensatory mechanism for defective 5mC oxidation in preimplantation embryos

    Distribution of Dust around Galaxies: An Analytic Model

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    We develop an analytic halo model for the distribution of dust around galaxies. The model results are compared with the observed surface dust density profile measured through reddening of background quasars in the Sloan Digital Sky Survey (SDSS) reported by Menard et al.(2010). We assume that the dust distribution around a galaxy is described by a simple power law, similarly to the mass distribution, but with a sharp cut-off at αRvir\alpha R_{\rm vir} where RvirR_{\rm vir} is the galaxy's virial radius and α\alpha is a model parameter. Our model reproduces the observed dust distribution profile very well over a wide range of radial distance of 10104h110 - 10^{4} h^{-1}kpc. For the characteristic galaxy halo mass of 2×1012h1M2\times 10^{12} h^{-1}M_{\odot} estimated for the SDSS galaxies, the best fit model is obtained if α\alpha is greater than unity, which suggests that dust is distributed to over a few hundred kilo-parsecs from the galaxies. The observed large-scale dust distribution profile is reproduced if we assume the total amount of dust is equal to that estimated from the integrated stellar evolution over the cosmic time.Comment: 5 pages, 4 figures, corrected typo and minor revisions, results unchanged, MNRAS Letters, in pres
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