Polarization of the Crab Nebula with disordered magnetic components

In this paper, we present an expanding disc model to derive polarization properties of the Crab nebula. The distribution function of the plasma and the energy density of the magnetic field are prescribed as function of the distance from the pulsar by using the model by Kennel and Coroniti (1984) with $\sigma = 0.003$, where $\sigma$ is the ratio of Poynting flux to the kinetic energy flux in the bulk motion just before the termination shock. Unlike previous models, we introduce disordered magnetic field, which is parameterized by the fractional energy density of the disordered component. Flow dynamics is not solved. The mean field is toroidal. Averaged polarization degree over the disc is obtained as a function of inclination angle and fractional energy density of the disordered magnetic field. It is found for the Crab that the disordered component has about 60 percent of the magnetic field energy. This value is also supported by the facts that the disc appears not `lip-shape' but as `rings' in the intensity map as was observed, and that the highest polarization degree of $\sim 40$ percent is reproduced for rings, being consistent with the observation. We suggest that because the disordered field contributes rather pressure than tension, the pinch force may be over-estimated in previous relativistic magnetohydrodynamic simulations. Disruption of the toroidal magnetic field with alternating direction, which is proposed by Lyubarski (2003), may actually takes place. The relativistic flow speed, which is indicated by the front-back contrast, can be detected in asymmetry in distributions of the position angle and depolarization.Comment: 7 pages, 8 figures, accepted for publication in MNRA

Toda Hierarchy with Indefinite Metric

We consider a generalization of the full symmetric Toda hierarchy where the matrix $\tilde {L}$ of the Lax pair is given by $\tilde {L}=LS$, with a full symmetric matrix $L$ and a nondegenerate diagonal matrix $S$. The key feature of the hierarchy is that the inverse scattering data includes a class of noncompact groups of matrices, such as $O(p,q)$. We give an explicit formula for the solution to the initial value problem of this hierarchy. The formula is obtained by generalizing the orthogonalization procedure of Szeg\"{o}, or the QR factorization method of Symes. The behaviors of the solutions are also studied. Generically, there are two types of solutions, having either sorting property or blowing up to infinity in finite time. The $\tau$-function structure for the tridiagonal hierarchy is also studied.Comment: 26 pages, LaTe

Little-Parks oscillations with half-quantum fluxoid features in Sr2RuO4 micro rings

In a micro ring of a superconductor with a spin-triplet equal-spin pairing state, a fluxoid, a combined object of magnetic flux and circulating supercurrent, can penetrate as half-integer multiples of the flux quantum. A candidate material to investigate such half-quantum fluxoids is Sr$_\mathsf{2}$RuO$_\mathsf{4}$. We fabricated Sr$_\mathsf{2}$RuO$_\mathsf{4}$ micro rings using single crystals and measured their resistance behavior under magnetic fields controlled with a three-axes vector magnet. Proper Little-Parks oscillations in the magnetovoltage as a function of an axially applied field, associated with fluxoid quantization are clearly observed, for the first time using bulk single crystalline superconductors. We then performed magnetovoltage measurements with additional in-plane magnetic fields. By carefully analyzing both the voltages $V_+$ ($V_-$) measured at positive (negative) current, we find that, above an in-plane threshold field of about 10 mT, the magnetovoltage maxima convert to minima. We interpret this behavior as the peak splitting expected for the half-quantum fluxoid states.Comment: 16 pages, 15 figure

Design and implementation of a videoconferencing-embedded flipped classroom (VEFC) in college-level EFL

This paper aims to describe the videoconferencing-embedded flipped classroom (VEFC) as a viable instructional design and practice to overcome the present challenge of Teaching English as an International English (TEIL) in Japan’s traditional EFL classroom. It will also discuss the effects and implications as a consequence of implementing this VEFC pedagogy in the classroom. Specifically, this paper will describe the four stages of VEFC: 1) out-of-class asynchronous task “connect with ELT scholars”; 2) in-class synchronous task “interact with ELT scholars”; 3) out-of-class asynchronous task “engage in reflective journals”; and 4) in-class synchronous task “collaborate to make a group presentation.” VEFC can be an effective pedagogical choice that teachers can adopt to prepare their students to become competent English users in other EFL contexts

The Pretreatment of Maximum Standardized Uptake Values (SUVmax) of the Primary Tumor Is Predictor for Poor Prognosis for Patients with Epithelial Ovarian Cancer

The purpose of this study was to evaluate prognostic factors for epithelial ovarian cancer. We found that the pretreatment values of maximum standardized uptake (SUVmax) of the primary tumor by positron emission tomography/computed tomography (PET/CT), tumor marker CA125 and C-reactive protein (CRP) were correlated with clinical characteristics and prognosis for such patients. The clinical parameters and prognoses and their correlations with SUVmax of primary tumor, CA125 and CRP were examined for 51 patients with primary ovarian cancer. The SUVmax of the primary tumor had a statistically significant association with stage (p＝0.010) and histology (p＝0.001). CA125 was significant associated with stage (p＝0.011), histology (p＝0.005) and lymph node metastasis (p＝0.025). CRP was also significantly associated with stage (p＝0.049). Disease-free survival rates of patients exhibiting a high SUVmax, CA125 and CRP were significantly lower than those exhibiting a low SUVmax, CA125 and CRP levels (p＝0.008, 0.034, and 0.037, respectively). Furthermore, overall survival rates of patients exhibiting a high SUVmax were significantly lower than those exhibiting a low SUVmax (p＝0.049).The high SUVmax of primary tumor is an important factor for identifying ovarian cancer patients with a predictor for poor prognosis

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Thesis--University of Tsukuba, D.Sc.(A), no. 238, 1984. 3. 2