722 research outputs found

    Projectile Fragmentation of the Extremely Neutron-Rich Nucleus ^<11>Li at o.79 GeV/nucleon

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    Projectile fragmentations of ^Li, ^He, and ^He have been measured at 0.79 GeV/nucleon. Production cross sections and momentum distributions of the produced isotopes (Z≄2) are measured inclusively. Transverse-momentum distributions of ^Li from the fragmentation of ^Li show two Gaussian components of different widths. The width of the wide component is consistent with the values observed in the fragmentation of stable nuclei, whereas the other component shows an extremely narrow width reflecting the weak binding of the two outer neutrons in the ^Li nucleus

    New neurons use Slit-Robo signaling to migrate through the glial meshwork and approach a lesion for functional regeneration

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    After brain injury, neural stem cell–derived neuronal precursors (neuroblasts) in the ventricular-subventricular zone migrate toward the lesion. However, the ability of the mammalian brain to regenerate neuronal circuits for functional recovery is quite limited. Here, using a mouse model for ischemic stroke, we show that neuroblast mi-gration is restricted by reactive astrocytes in and around the lesion. To migrate, the neuroblasts use Slit1-Robo2 signaling to disrupt the actin cytoskeleton in reactive astrocytes at the site of contact. Slit1-overexpressing neu-roblasts transplanted into the poststroke brain migrated closer to the lesion than did control neuroblasts. These neuroblasts matured into striatal neurons and efficiently regenerated neuronal circuits, resulting in functional recovery in the poststroke mice. These results suggest that the positioning of new neurons will be critical for func-tional neuronal regeneration in stem/progenitor cell–based therapies for brain injury

    Search for the decay KL0→3γK_L^0 \rightarrow 3\gamma

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    We performed a search for the decay KL0→3ÎłK_L^0 \rightarrow 3\gamma with the E391a detector at KEK. In the data accumulated in 2005, no event was observed in the signal region. Based on the assumption of KL0→3ÎłK_L^0 \rightarrow 3\gamma proceeding via parity-violation, we obtained the single event sensitivity to be (3.23±0.14)×10−8(3.23\pm0.14)\times10^{-8}, and set an upper limit on the branching ratio to be 7.4×10−87.4\times10^{-8} at the 90% confidence level. This is a factor of 3.2 improvement compared to the previous results. The results of KL0→3ÎłK_L^0 \rightarrow 3\gamma proceeding via parity-conservation were also presented in this paper

    Improved measurement of the K+->pi+nu(nu)over-bar branching ratio

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    An additional event near the upper kinematic limit for K+-->pi(+)nu(nu) over bar has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nu(nu) over bar)=(1.47(-0.89)(+1.30))x10(-10) based on three events observed in the pion momentum region 211<P<229 MeV/c. At the measured central value of the branching ratio, the additional event had a signal-to-background ratio of 0.9
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