1,046 research outputs found

    Temperature-Dependent Cycloidal Magnetic Structure in GdRu2_{2}Al10_{10} Studied by Resonant X-ray Diffraction

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    We have performed resonant X-ray diffraction experiments on the antiferromagnet GdRu2_{2}Al10_{10} and have clarified that the magnetic structure in the ordered state is cycloidal with the moments lying in the bcbc plane and propagating along the bb axis. The propagation vector shows a similar temperature dependence to the magnetic order parameter, which can be interpreted as being associated with the gap opening in the conduction band and the resultant change in the magnetic exchange interaction. Although the S=7/2S=7/2 state of Gd is almost isotropic, the moments show slight preferential ordering along the bb axis. The cc axis component in the cycloid develops with decreasing temperature through a tiny transition in the ordered phase. We also show that the scattering involves the σ\sigma-σ\sigma' process, which is forbidden in normal E1E1-E1E1 resonance of magnetic dipole origin. We discuss the possibility of the E1E1-E2E2 resonance originating from a toroidal moment due to the lack of inversion symmetry at the Gd site. The spin-flop transition in a magnetic field is also described in detail.Comment: 8 pages, 11 figures, accepted for publication in J. Phys. Soc. Jp

    Speaker clustering in multi‐party conversation

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    Proceedings of the 3rd Nordic Symposium on Multimodal Communication. Editors: Patrizia Paggio, Elisabeth Ahlsén, Jens Allwood, Kristiina Jokinen, Costanza Navarretta. NEALT Proceedings Series, Vol. 15 (2011), 56–61. © 2011 The editors and contributors. Published by Northern European Association for Language Technology (NEALT) http://omilia.uio.no/nealt . Electronically published at Tartu University Library (Estonia) http://hdl.handle.net/10062/22532

    Pontine infarction caused by medial branch injury of the basilar artery as a rare complication of cisternal drain placement

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    We present a rare complication of cisternal drain placement during aneurysm surgery. A ruptured anterior communicating artery aneurysm was clipped through a right pterional approach. A cisternal drain was inserted from the retro-carotid to the prepontine cistern. Postoperatively, a left-sided paresis of the upper extremity had developed. A CT brain scan revealed that the drain was located between the pons and the basilar artery, resulting in a pontine infarction. Vascular neurosurgeons should keep this complication in mind when placing a cisternal drain tube. The drain tube should not be inserted too deep into the prepontine cistern.ArticleJOURNAL OF CLINICAL NEUROSCIENCE. 19(4):592-593 (2012)journal articl

    Mapping Observations of DNC and HN^13C in Dark Cloud Cores

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    We present results of mapping observations of the DNC, HN^13C, and H^13CO^+ lines (J=1-0) toward 4 nearby dark cloud cores, TMC-1, L1512, L1544, and L63, along with observations of the DNC and HN^13C lines (J=2-1) toward selected positions. By use of statistical equilibrium calculations based on the LVG model, the H_2 densities are derived to be (1.4-5.5)*10^5 cm^-3, and the [DNC]/[HN^13C] ratios are derived to be 1.25-5.44 with a typical uncertainty by a factor of 2. The observed [DNC]/[HNC] ratios range from 0.02 to 0.09, assuming the [^12C]/[^13C] ratio of 60. Distributions of DNC and HN^13C are generally similar to each other, whereas the distribution of H^13CO^+ is more extended than those of DNC and HN^13C, indicating that they reside in an inner part of the cores than HCO^+. The [DNC]/[HN^13C] ratio is rather constant within each core, although a small systematic gradients are observed in TMC-1 and L63. Particularly, no such systematic gradient is found in L1512 and L1544, where a significant effect of depletion of molecules is reported toward the central part of the cores. This suggests that the [DNC]/[HNC] ratio would not be very sensitive to depletion factor, unlike the [DCO^+]/[HCO^+] ratio. On the other hand, the core to core variation of the [DNC]/[HNC] ratio, which range an order of magnitude, is more remarkable than the variation within each core. These results are interpreted qualitatively by a combination of three competing time-dependent processes; gas-phase deuterium fractionation, depletion of molecules onto grain surface, and dynamical evolution of a core.Comment: 22 pages, 8 EPS figures, aasLaTex 5.0, accepted to The Astrophysical Journa