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Kofu-shi, Japan

Yamanashi Gakuin University is a university in KōfuYamanashi Prefecture, Japan. Wikipedia.

Okazaki A.T.,Hokkai Gakuen University | Nagataki S.,Yukawa Institute for Theoretical Physics | Naito T.,Yamanashi Gakuin University | Kawachi A.,Tokai University | And 3 more authors.
Publications of the Astronomical Society of Japan | Year: 2011

We have been studying the interaction between the Be star and the pulsar in the TeV binary PSR B1259 63/LS 2883, using 3-D SPH simulations of the tidal and wind interactions in this Be-pulsar system. We first ran a simulation without pulsar wind nor Be wind, while taking into account only the gravitational effect of the pulsar on the Be disk. In this simulation, the gas particles are ejected at a constant rate from the equatorial surface of the Be star, which is tilted in a direction consistent with multi-waveband observations. We ran the simulation until the Be disk was fully developed and started to repeat a regular tidal interaction with the pulsar. Then, we turned on the pulsar wind and the Be wind. We ran two simulations with different wind mass-loss rates for the Be star, one for a B2V type and the other for a significantly earlier spectral type. Although the global shape of the interaction surface between the pulsar wind and the Be wind agrees with the analytical solution, the effect of the pulsar wind on the Be disk is profound. The pulsar wind strips off an outer part of the Be disk, truncating the disk at a radius significantly smaller than the pulsar orbit. Our results, therefore, rule out the idea that the pulsar passes through the Be disk around periastron, which has been assumed in previous studies. It also turns out that the location of the contact discontinuity can be significantly different between phases when the pulsar wind directly hits the Be disk and those when the pulsar wind collides with the Be wind. It is thus important to adequately take into account the circumstellar environment of the Be star, in order to construct a satisfactory model for this prototypical TeV binary. © 2011. Astronomical Society of Japan. Source

Kaburagi T.,Daito Bunka University | Hirasawa R.,University of Tsukuba | Yoshino H.,Yamanashi Gakuin University | Odaka Y.,Japan Womens University | And 5 more authors.
Public Health Nutrition | Year: 2011

Objectives To evaluate the utility of the Mini-Nutritional Assessment (MNA) in assessing nutritional, physical and psychosocial functions in community-living elderly individuals.Design A cross-sectional study of elderly individuals investigated in August 2007 and August-September 2008. Nutritional status was assessed using serum biomarkers, anthropometric measurements and the MNA. Physical function was assessed by measuring grip strength and both usual and maximum walking speeds. The Geriatric Depression Scale (GDS) was used to measure the individual's depressive state.Setting Elder-care facilities in Tokyo, Japan.Subjects Community-living elderly individuals aged ≥65 years (n 130).Results The MNA evaluation classified twenty-seven (20.8 %) individuals as being at risk for malnutrition (MNA score ≤23.5); these at-risk individuals included a high proportion of the elderly aged ≥75 years. MNA scores correlated with nutritional biomarkers (total protein, albumin, cholinesterase, Hb) and anthropometric measurements (triceps skinfold, subscapular skinfold, mid-arm muscle area) and exhibited a strong correlation with grip strength and GDS score. Multivariate analysis revealed that grip strength, GDS score, marital status and maximum walking speed are strong predictors of MNA score.Conclusions The MNA is considerably useful in providing a comprehensive assessment of nutritional status in elderly, community-living Japanese. However, larger-scale epidemiological studies are needed to determine the utility and the appropriate cut-off point of the MNA as a screen for risk of malnutrition. © 2011 The Authors. Source

Parida A.,Jamia Millia Islamia University | Mitra S.,Inter-University Center for Astronomy and Astrophysics | Jhingan S.,Jamia Millia Islamia University | Jhingan S.,Yamanashi Gakuin University
Journal of Cosmology and Astroparticle Physics | Year: 2016

A Gravitational Wave Background (GWB) is expected in the universe from the superposition of a large number of unresolved astrophysical sources and phenomena in the early universe. Each component of the background (e.g., from primordial metric perturbations, binary neutron stars, milli-second pulsars etc.) has its own spectral shape. Many ongoing experiments aim to probe GWB at a variety of frequency bands. In the last two decades, using data from ground-based laser interferometric gravitational wave (GW) observatories, upper limits on GWB were placed in the frequency range of 0∼ 50-100 Hz, considering one spectral shape at a time. However, one strong component can significantly enhance the estimated strength of another component. Hence, estimation of the amplitudes of the components with different spectral shapes should be done jointly. Here we propose a method for "component separation" of a statistically isotropic background, that can, for the first time, jointly estimate the amplitudes of many components and place upper limits. The method is rather straightforward and needs negligible amount of computation. It utilises the linear relationship between the measurements and the amplitudes of the actual components, alleviating the need for a sampling based method, e.g., Markov Chain Monte Carlo (MCMC) or matched filtering, which are computationally intensive and cumbersome in a multi-dimensional parameter space. Using this formalism we could also study how many independent components can be separated using a given dataset from a network of current and upcoming ground based interferometric detectors. © 2016 IOP Publishing Ltd and Sissa Medialab srl . Source

Hirano K.,Nagoya University | Ohgomori T.,Nagoya University | Kobayashi K.,Nagoya University | Tanaka F.,Nagoya University | And 12 more authors.
PLoS ONE | Year: 2013

Biopolymers consist of three major classes, i.e., polynucleotides (DNA, RNA), polypeptides (proteins) and polysaccharides (sugar chains). It is widely accepted that polynucleotides and polypeptides play fundamental roles in the pathogenesis of neurodegenerative diseases. But, sugar chains have been poorly studied in this process, and their biological/clinical significance remains largely unexplored. Amyotrophic lateral sclerosis (ALS) is a motoneuron-degenerative disease, the pathogenesis of which requires both cell autonomous and non-cell autonomous processes. Here, we investigated the role of keratan sulfate (KS), a sulfated long sugar chain of proteoglycan, in ALS pathogenesis. We employed ALS model SOD1G93A mice and GlcNAc6ST-1-/- mice, which are KS-deficient in the central nervous system. Unexpectedly, SOD1G93AGlcNAc6ST-1-/- mice exhibited a significantly shorter lifespan than SOD1G93A mice and an accelerated appearance of clinical symptoms (body weight loss and decreased rotarod performance). KS expression was induced exclusively in a subpopulation of microglia in SOD1G93A mice, and became detectable around motoneurons in the ventral horn during the early disease phase before body weight loss. During this phase, the expression of M2 microglia markers was transiently enhanced in SOD1G93A mice, while this enhancement was attenuated in SOD1G93AGlcNAc6ST-1-/- mice. Consistent with this, M2 microglia were markedly less during the early disease phase in SOD1G93AGlcNAc6ST-1-/- mice. Moreover, KS expression in microglia was also detected in some human ALS cases. This study suggests that KS plays an indispensable, suppressive role in the early phase pathogenesis of ALS and may represent a new target for therapeutic intervention. © 2013 Hirano et al. Source

Hayasaki K.,Korea Astronomy and Space Science Institute | Sohn B.W.,Korea Astronomy and Space Science Institute | Sohn B.W.,Korean University of Science and Technology | Okazaki A.T.,Hokkai Gakuen University | And 3 more authors.
Astrophysical Journal | Year: 2014

We study a warping instability of a geometrically thin, non-self-gravitating disk surrounding binary supermassive black holes on a circular orbit. Such a circumbinary disk is subject to not only tidal torques due to the binary gravitational potential but also radiative torques due to radiation emitted from an accretion disk around each black hole. We find that a circumbinary disk initially aligned with the binary orbital plane is unstable to radiation-driven warping beyond the marginally stable warping radius, which is sensitive to both the ratio of vertical to horizontal shear viscosities and the mass-to-energy conversion efficiency. As expected, the tidal torques give no contribution to the growth of warping modes but tend to align the circumbinary disk with the orbital plane. Since the tidal torques can suppress the warping modes in the inner part of circumbinary disk, the circumbinary disk starts to be warped at radii larger than the marginally stable warping radius. If the warping radius is of the order of 0.1 pc, a resultant semi-major axis is estimated to be of the order of 10-2 pc to 10-4 pc for 107 M black hole. We also discuss the possibility that the central objects of observed warped maser disks in active galactic nuclei are binary supermassive black holes with a triple disk: two accretion disks around the individual black holes and one circumbinary disk surrounding them. © 2014. The American Astronomical Society. All rights reserved.. Source

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