Inequivalent Quantization in the Skyrme Model

Quantum mechanics on manifolds is not unique and in general infinite number of inequivalent quantizations can be considered. They are specified by the induced spin and the induced gauge structures on the manifold. The configuration space of collective mode in the Skyrme model can be identified with $S^{3}$ and thus the quantization is not unique. This leads to the different predictions for the physical observables.Comment: 16 pages, LaTeX2

Current-perpendicular-to-plane giant magnetoresistance of a spin valve using Co2MnSi Heusler alloy electrodes

We report the current-perpendicular-to-plane giant magnetoresistance of a spin valve with Co2MnSi (CMS) Heusler alloy ferromagnetic electrodes. A multilayer stack of Cr/Ag/Cr/CMS/Cu/CMS/Fe25Co75/Ir28Mn72/Ru was deposited on a MgO (001) single crystal substrate. The bottom CMS layer was epitaxially grown on the Cr/Ag/Cr buffer layers and was ordered to the L21 structure after annealing at 673 K. The upper CMS layer was found to grow epitaxially on the Cu spacer layer despite the large lattice mismatch between Cu and CMS. The highest MR ratios of 8.6% and 30.7% for CPP-GMR were recorded at room temperature and 6 K, respectively. The high spin polarization of the epitaxial CMS layers is the most likely origin of the high MR ratio.Comment: 14 pages, 3 figures, presented at the 53rd Annual Conference on Magnetism and Magnetic Materials, to be published in J. Appl. Phy

Real-space observation of current-driven domain wall motion in submicron magnetic wires

Spintronic devices, whose operation is based on the motion of a magnetic domain wall (DW), have been proposed recently. If a DW could be driven directly by flowing an electric current instead of a magnetic field, the performance and functions of such device would be drastically improved. Here we report real-space observation of the current-driven DW motion by using a well-defined single DW in a micro-fabricated magnetic wire with submicron width. Magnetic force microscopy (MFM) visualizes that a single DW introduced in the wire is displaced back and forth by positive and negative pulsed-current, respectively. We can control the DW position in the wire by tuning the intensity, the duration and the polarity of the pulsed-current. It is, thus, demonstrated that spintronic device operation by the current-driven DW motion is possible.Comment: Accepted and published in PR

Significance of myocardial tenascin-C expression in left ventricular remodelling and long-term outcome in patients with dilated cardiomyopathy

Aim Dilated cardiomyopathy (DCM) has a variety of causes, and no useful approach to predict left ventricular (LV) remodelling and long-term outcome has yet been established. Myocardial tenascin-C (TNC) is known to appear under pathological conditions, possibly to regulate cardiac remodelling. The aim of this study was to clarify the significance of myocardial TNC expression in LV remodelling and the long-term outcome in DCM. Methods and results One hundred and twenty-three consecutive DCM patients who underwent endomyocardial biopsy for initial diagnosis were studied. Expression of TNC in biopsy sections was analysed immunohistochemically to quantify the ratio of the TNC-positive area to the whole myocardial tissue area (TNC area). Clinical parameters associated with TNC area were investigated. The patients were divided into two groups based on receiver operating characteristic analysis of TNC area to predict death: high TNC group with TNC area ≥2.3% (22 patients) and low TNC group with TNC area <2.3% (101 patients). High TNC was associated with diabetes mellitus. Comparing echocardiographic findings between before and 9 months after endomyocardial biopsy, the low TNC group was associated with decreased LV end-diastolic diameter and increased LV ejection fraction, whereas the high TNC group was not. Survival analysis revealed a worse outcome in the high TNC group than in the low TNC group (P < 0.001). Multivariable Cox regression analysis revealed that TNC area was independently associated with poor outcome (HR = 1.347, P = 0.032). Conclusions Increased myocardial TNC expression was associated with worse LV remodeling and long-term outcome in DCM

A scheduling and diagnostic system for scientific satellite GEOTAIL using expert system

The Intelligent Satellite Control Software (ISACS) for the geoMagnetic tail observation satellite named GEOTAIL (launched in July 1992) has been successfully developed. ISACS has made it possible by applying Artificial Intelligence (AI) technology including an expert system to autonomously generate a tracking schedule, which originally used to be conducted manually. Using ISACS, a satellite operator can generate a maximum four day period of stored command stream autonomously and can easily confirm its safety. The ISACS system has another function -- to diagnose satellite troubles and to suggest necessary remedies. The workload of satellite operators has drastically been reduced since ISACS has been introduced into the operations of GEOTAIL