6,197 research outputs found

    Xenopus NM23-X4 regulates retinal gliogenesis through interaction with p27Xic1

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    Background. In Xenopus retinogenesis, p27Xic1, a Xenopus cyclin dependent kinase inhibitor, functions as a cell fate determinant in both gliogenesis and neurogenesis in a context dependent manner. This activity is essential for co-ordination of determination and cell cycle regulation. However, very little is known about the mechanism regulating the context dependent choice between gliogenesis versus neurogenesis. Results. We have identified NM23-X4, a NM23 family member, as a binding partner of p27Xic1. NM23-X4 is expressed at the periphery of the ciliary marginal zone of the Xenopus retina and the expression overlaps with p27Xic1 at the central side. Our in vivo functional analysis in Xenopus retina has shown that knockdown of NM23-X4 activates gliogenesis. Furthermore, co-overexpression of NM23-X4 with p27Xic1 results in the inhibition of p27Xic1-mediated gliogenesis, through direct interaction of NM23-X4 with the amino-terminal side of p27Xic1. This inhibitory effect on gliogenesis requires serine-150 and histidine-148, which correspond to the important residues for the kinase activities of NM23 family members. Conclusion. This study demonstrates that NM23-X4 functions as an inhibitor of p27Xic1-mediated gliogenesis in Xenopus retina and suggests that this activity contributes to the proper spatio-temporal regulation of gliogenesis

    Recombination kinetics of a dense electron-hole plasma in strontium titanate

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    We investigated the nanosecond-scale time decay of the blue-green light emitted by nominally pure SrTiO3_3 following the absorption of an intense picosecond laser pulse generating a high density of electron-hole pairs. Two independent components are identified in the fluorescence signal that show a different dynamics with varying excitation intensity, and which can be respectively modeled as a bimolecular and unimolecolar process. An interpretation of the observed recombination kinetics in terms of interacting electron and hole polarons is proposed

    Roles of Bond Alternation in Magnetic Phase Diagram of RMnO3

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    In order to investigate nature of the antiferromagnetic structures in perovskite RMnO3, we study a Heisenberg J1-J2 model with bond alternation using analytical and numerical approaches. The magnetic phase diagram which includes incommensurate spiral states and commensurate collinear states is reproduced. We discuss that the magnetic structure with up-up-down-down spin configuration (E-type structure) and the ferroelectricity emerge cooperatively to stabilize this phase. Magnetoelastic couplings are crucial to understand the magnetic and electric phase diagram of RMnO3.Comment: 5 pages, 6 figure

    Specific Heat and Superfluid Density for Possible Two Different Superconducting States in NaxCoO2.yH2O

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    Several thermodynamic measurements for the cobaltate superconductor, NaxCoO2.yH2O, have so far provided results inconsistent with each other. In order to solve the discrepancies, we microscopically calculate the temperature dependences of specific heat and superfluid density for this superconductor. We show that two distinct specific-heat data from Oeschler et al. and Jin et al. are reproduced, respectively, for the extended s-wave state and the p-wave state. Two different superfluid-density data are also reproduced for each case. These support our recent proposal of possible two different pairing states in this material. In addition, we discuss the experimentally proposed large residual Sommerfeld coefficient and extremely huge effective carrier mass.Comment: 5 pages, 4 figures, Submitted to J. Phys. Soc. Jp

    Measurements of mass ablation rate and pressure in planar targets irradiated by 0.27-μm laser light

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    Copyright 1986 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, 60(11), 3840-3844, 1986 and may be found at http://dx.doi.org/10.1063/1.33755

    Fulde-Ferrell-Larkin-Ovchinnikov State in the absence of a Magnetic Field

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    We propose that in a system with pocket Fermi surfaces, a pairing state with a finite total momentum q_tot like the Fulde-Ferrell-Larkin-Ovchinnikov state can be stabilized even without a magnetic field. When a pair is composed of electrons on a pocket Fermi surface whose center is not located at Gamma point, the pair inevitably has finite q_tot. To investigate this possibility, we consider a two-orbital model on a square lattice that can realize pocket Fermi surfaces and we apply fluctuation exchange approximation. Then, by changing the electron number n per site, we indeed find that such superconducting states with finite q_tot are stabilized when the system has pocket Fermi surfaces.Comment: 4 pages, 5 figure

    INFLUENCE OF DIFFERENT SHOULDER ABDUCTION ANGLES DURING BASEBALL PlTCHING ON 'THROWING PERFORMANCE AND JOINT KINETICS

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    The relationships between shoulder abduction angle at ball release and wrist velocity and several injury-related kinetic parameters were investigated. Based on kinematic data of nine overhand and three-quarter-hand pitchers, several pitching motions with different shoulder abduction angles from the original were simulated. The wrist velocity and several injury-related kinetic parameters for the motion with 90 degree shoulder abduction angle at ball release were compared with those for the motions with other shoulder abduction angles. The 90 degree abduction angle maximised wrist velocity and decreased elbow joint kinetics, but did not always decrease shoulder joint kinetics

    Mainstreaming of climate extreme risk into fiscal and budgetary planning: application of stochastic debt and disaster fund analysis in Austria

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    While ageing-related costs are perceived as the major drivers of fiscal pressure in the EU, concerns over climate-related public expenditures have received comparatively little attention in securing the EU’s long-term fiscal sustainability. Using the Shared Socioeconomic Pathways (SSPs) scenarios as bridging concept for linking the assessment of public cost of demography- and climate-related expenditures, this study proposes a climate risk mainstreaming methodology. We apply a stochastic debt model and assess the potential flood risk in Austria to the public debt and the national disaster fund. Our results indicate that public debt under no fiscal consolidation is estimated to increase from the current level of 84.5% relative to GDP in 2015 to 92.1% in 2030, with macroeconomic variability adding further risk to the country’s baseline public debt trajectory. The study finds that the estimated public contingent liability due to expected flood risk is small relative to the size of economy. The existing earmarked disaster risk reduction (DRR) funding will likely reduce the risk of frequent-and-low impact floods, yet the current budgetary arrangement may be insufficient to deal with rising risk of extreme floods in the future. This prompts the need for further discussions regarding potential reforms of the disaster fund. As many EU member states are in the early stages of designing climate change policy strategies, the proposed method can support the mainstreaming of climate-related concerns into longer-term fiscal and budgetary planning

    Sub-Cycle Optical Response Caused by Dressed State with Phase-Locked Wavefunctions

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    The coherent interaction of light with matter imprints the phase information of the light field on the wavefunction of the photon-dressed electronic state. Driving electric field, together with a stable phase that is associated with the optical probe pulses, enables the role of the dressed state in the optical response to be investigated. We observed optical absorption strengths modulated on a sub-cycle timescale in a GaAs quantum well in the presence of a multi-cycle terahertz driving pulse using a near-infrared probe pulse. The measurements were in good agreement with the analytical formula that accounts for the optical susceptibilities caused by the dressed state of excitons, which indicates that the output probe intensity was coherently reshaped by the excitonic sideband emissions
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