Outburst of LS V+44 17 Observed by MAXI and RXTE, and Discovery of a Dip Structure in the Pulse Profile

We report on the first observation of an X-ray outburst of a Be/X-ray binary pulsar LS V +44 17/RX J0440.9+4431, and the discovery of an absorption dip structure in the pulse profile. An outburst of this source was discovered by MAXI GSC in 2010 April. It was the first detection of the transient activity of LS V +44 17 since the source was identified as a Be/X-ray binary in 1997. From the data of the follow-up RXTE observation near the peak of the outburst, we found a narrow dip structure in its pulse profile which was clearer in the lower energy bands. The pulse-phase-averaged energy spectra in the 3$-$100 keV band can be fitted with a continuum model containing a power-law function with an exponential cutoff and a blackbody component, which are modified at low energy by an absorption component. A weak iron K$\alpha$ emission line is also detected in the spectra. From the pulse-phase-resolved spectroscopy we found that the absorption column density at the dip phase was much higher than those in the other phases. The dip was not seen in the subsequent RXTE observations at lower flux levels. These results suggest that the dip in the pulse profile originates from the eclipse of the radiation from the neutron star by the accretion column.Comment: 18 pages, 7 figures, accepted for publication in PAS

A Spectral Study of the Black Hole Candidate XTE J1752-223 in the High/Soft State with MAXI, Suzaku and Swift

We report on the X-ray spectral analysis of the black hole candidate XTE\ J1752--223 in the 2009--2010 outburst, utilizing data obtained with the MAXI/Gas Slit Camera (GSC), the Swift/XRT, and Suzaku, which work complementarily. As already reported by Nakahira et al. (2010) MAXI monitored the source continuously throughout the entire outburst for about eight months. All the MAXI/GSC energy spectra in the high/soft state lasting for 2 months are well represented by a multi-color disk plus power-law model. The innermost disk temperature changed from $\sim$0.7 keV to $\sim$0.4 keV and the disk flux decreased by an order of magnitude. Nevertheless, the innermost radius is constant at $\sim$41 $D_{3.5}(\cos{\it i})^{-1/2}$ km, where $D_{3.5}$ is the source distance in units of 3.5 kpc and $i$ the inclination. The multi-color disk parameters obtained with the MAXI/GSC are consistent with those with the Swift/XRT and Suzaku. The Suzaku data also suggests a possibility that the disk emission is slightly Comptonized, which could account for broad iron-K features reported previously. Assuming that the obtained innermost radius represents the innermost stable circular orbit for a non-rotating black hole, we estimate the mass of the black hole to be 5.51$\pm$0.28 $M_{\odot}$ $D_{3.5}(\cos{\it i})^{-1/2}$, where the correction for the stress-free inner boundary condition and color hardening factor of 1.7 are taken into account. If the inclination is less than 49$^{\circ}$ as suggested from the radio monitoring of transient jets and the soft-to-hard transition in 2010 April occurred at 1--4% of Eddignton luminosity, the fitting of the Suzaku spectra with a relativistic accretion-disk model derives constraints on the mass and the distance to be 3.1--55 $M_{\odot}$ and 2.3--22 {\rm kpc}, respectively. This confirms that the compact object in XTE J1752--223 is a black hole.Comment: 12 pages including 7 figures and 4 tables, accepted for publication in PAS

Laparoscopic Non-clamping Tumor Enucleation of Renal Hilum Schwannoma in a Single Kidney: A Case Report

A 56-year-old woman underwent laparoscopic right nephrectomy due to pyonephrosis associated with right ureteral stones. Moreover, the patient developed a brain stem hemorrhage and became bedridden. At the time of nephrectomy, a renal tumor, with a size of 24 × 24 × 20 mm, was observed in the left renal hilum; the tumor did not show contrast enhancement on computed tomography. After 3 years, the tumor gradually grew to a size of 45 × 35 × 34 mm, and therefore, laparoscopic non-clamping tumor enucleation was performed. Pathological examination confirmed a diagnosis of renal schwannoma

Relationships among motivation, psychological needs, FL WTC, and Can-Do statements of English language learning based on Self-Determination Theory : Preliminary study of non-English-major junior college students in Japan

本研究は、英語を専攻としていない日本人短期大学生163名を対象として、動機づけ、心理的欲求、外国語での自発的にコミュニケーションを図る意思(八島,2009)(FL WTC)、英語力の認識(Can-Do statements[STEP])の関係を明らかにすることを目的としている。具体的には、自己決定理論を動機づけの枠組みとして用い、1)内発的動機づけの保持に最も影響を与えている心理的欲求を明らかにし、2)高いFLWTCを持つことと内発的動機づけとの関わりを探る。更に、3)英語力の認識 (Can-Do statements)と高い内発的動機づけの保持との関わりについても示していく。調査の結果、1)心理的欲求の中でも特に有能性の欲求が満たされることが、最も内発的動機づけに影響する要因であることが明らかとなり、更に2)高いFL WTCを持つ学習者は特に自己決定度の高い外発動機づけと関係を持つことが分かった。最後に、3)自己の英語力に対して肯定的な認識を持つ学習者は、高い内発動機づけを保持することが示された。このことから、授業内で「出来る」と感じることが内発動機づけの高まりを助け、更に自発的に英語でコミュニケー ションを図る意思を保持することは、自己決定度の高い外発的な動機づけとなることが示唆された。一方、肯定的な英語力の認識は内発的動機づけと最も強い関係を持つことからも、教育の場においてコミュニケーションの意思を高める働きかけのみではなく、実際に英語を使用する場面を増やすなどし、学習者が自身の英語力に肯定的な認識を保持する機会を設けることが重要であると考えられた