1,342 research outputs found

    H-Alpha and Hard X-Ray Observations of a Two-Ribbon Flare Associated with a Filament Eruption

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    We perform a multi-wavelength study of a two-ribbon flare on 2002 September 29 and its associated filament eruption, observed simultaneously in the H-alpha line by a ground-based imaging spectrograph and in hard X-rays by RHESSI. The flare ribbons contain several H-alpha bright kernels that show different evolutional behaviors. In particular, we find two kernels that may be the footpoints of a loop. A single hard X-ray source appears to cover these two kernels and to move across the magnetic neutral line. We explain this as a result of the merging of two footpoint sources that show gradually asymmetric emission owing to an asymmetric magnetic topology of the newly reconnected loops. In one of the H-alpha kernels, we detect a continuum enhancement at the visible wavelength. By checking its spatial and temporal relationship with the hard X-ray emission, we ascribe it as being caused by electron beam precipitation. In addition, we derive the line-of-sight velocity of the filament plasma based on the Doppler shift of the filament-caused absorption in the H-alpha blue wing. The filament shows rapid acceleration during the impulsive phase. These observational features are in principal consistent with the general scenario of the canonical two-ribbon flare model.Comment: 15 pages, 5 figures, accepted for publication in Ap

    Polymorphisms of human vascular endothelial growth factor gene in high-altitude pulmonary oedema susceptible subjects

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    The definitive version is available at www.blackwell-synergy.comArticleRESPIROLOGY. 14(1):46-52 (2009)journal articl

    Tuning of magnetic quantum criticality in artificial Kondo superlattice CeRhIn5/YbRhIn5

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    The effects of reduced dimensions and the interfaces on antiferromagnetic quantum criticality are studied in epitaxial Kondo superlattices, with alternating nn layers of heavy-fermion antiferromagnet CeRhIn5_5 and 7 layers of normal metal YbRhIn5_5. As nn is reduced, the Kondo coherence temperature is suppressed due to the reduction of effective Kondo screening. The N\'{e}el temperature is gradually suppressed as nn decreases and the quasiparticle mass is strongly enhanced, implying dimensional control toward quantum criticality. Magnetotransport measurements reveal that a quantum critical point is reached for n=3n=3 superlattice by applying small magnetic fields. Remarkably, the anisotropy of the quantum critical field is opposite to the expectations from the magnetic susceptibility in bulk CeRhIn5_5, suggesting that the Rashba spin-orbit interaction arising from the inversion symmetry breaking at the interface plays a key role for tuning the quantum criticality in the two-dimensional Kondo lattice.Comment: Main text: 5 pages, 4 figures; Supplemental material:6 pages, 3 figures. Accepted for publication in Physical Review Letter

    Self-Consistent MHD Modeling of a Coronal Mass Ejection, Coronal Dimming, and a Giant Cusp-Shaped Arcade Formation

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    We performed magnetohydrodynamic simulation of coronal mass ejections (CMEs) and associated giant arcade formations, and the results suggested new interpretations of observations of CMEs. We performed two cases of the simulation: with and without heat conduction. Comparing between the results of the two cases, we found that reconnection rate in the conductive case is a little higher than that in the adiabatic case and the temperature of the loop top is consistent with the theoretical value predicted by the Yokoyama-Shibata scaling law. The dynamical properties such as velocity and magnetic fields are similar in the two cases, whereas thermal properties such as temperature and density are very different.In both cases, slow shocks associated with magnetic reconnectionpropagate from the reconnection region along the magnetic field lines around the flux rope, and the shock fronts form spiral patterns. Just outside the slow shocks, the plasma density decreased a great deal. The soft X-ray images synthesized from the numerical results are compared with the soft X-ray images of a giant arcade observed with the Soft X-ray Telescope aboard {\it Yohkoh}, it is confirmed that the effect of heat conduction is significant for the detailed comparison between simulation and observation. The comparison between synthesized and observed soft X-ray images provides new interpretations of various features associated with CMEs and giant arcades.Comment: 39 pages, 18 figures. Accepted for publication in the Astrophysical Journal. The PDF file with high resplution figures can be downloaded from http://www.kwasan.kyoto-u.ac.jp/~shiota/study/ApJ62426.preprint.pdf

    Reduced lung uptake of iodine-123 metaiodobenzylguanidine in high-altitude pulmonary oedema

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    The definitive version is available at www.blackwell-synergy.com.ArticleRESPIROLOGY. 13(6):897-902(2008)journal articl
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