SiO Maser Survey off the Galactic Plane: A Signature of Streaming Motion

A group of Mira variables in the solar neighborhood show unusual spatial motion in the Galaxy. To study this motion in a much larger scale in the Galaxy, we newly surveyed 134 evolved stars off the Galactic plane by SiO maser lines, obtaining accurate radial velocities of 84 detected stars. Together with the past data of SiO maser sources, we analyzed the radial velocity data of a large sample of sources distributing in a distance range of about 0.3 -- 6 kpc in the first Galactic quadrant. At the Galactic longitudes between 20 and 40 deg, we found a group of stars with large negative radial velocities, which deviate by more than 100 km s^{-1} from the Galactic rotation. We show that these deviant motions of maser stars are created by periodic gravitational perturbation of the Bulge bar, and that the effect appears most strongly at radii between corotation and outer Lindblad resonances. The resonance effect can explain the displacement of positions from the Galactic plane as well.Comment: 14 pages, 11 figures, PASJ, 62. No. 3 in press high resolution figures available from http://www.nro.nao.ac.jp/~lib_pub/report/data/no675.pd

A Search for Water Masers in the Saturnian System

We searched for H2O 6(1,6)-5(2,3) maser emission at 22.235 GHz from several Saturnian satellites with the Nobeyama 45m radio telescope in May 2009. Observations were made for Titan, Hyperion, Enceladus and Atlas, for which Pogrebenko et al. (2009) had reported detections of water masers at 22.235 GHz, and in addition for Iapetus and other inner satellites. We detected no emission of the water maser line for all the satellites observed, although sensitivities of our observations were comparable or even better than those of Pogrebenko et al.. We infer that the water maser emission from the Saturnian system is extremely weak, or sporadic in nature. Monitoring over a long period and obtaining statistical results must be made for the further understanding of the water maser emission in the Saturnian system.Comment: 8 pages, 2 figures, accepted for publication in PASJ (Letter

国際ボランティアプロジェクトにおける第二言語を用いた意味交渉としての異文化学習：コミュニティオブプラクティスの観点から

関西大

Intercultural Learning as Negotiation of Meaning Using a Second Language in an International Volunteer Project : A Community of Practice Perspective [論文要旨及び審査の要旨]

関西大

リコウケイ ガクセイ ノ コクサイリョク ハ ドノヨウニ コウジョウ スルノカ センザイテキ グローバル ジンザイ ノ イクセイ ニ カンスル ジッショウ ケンキュウ

Low-resistivity and excellent-adhesion Cu(Ti) alloy films were prepared on glass substrates. Cu(0:3-4 at%Ti) alloy films were deposited on the substrates, and subsequently annealed in vacuum at 400℃ for 3 h. Resistivity of the annealed Cu(Ti) alloy films was significantly reduced to about 2.8μΩcm. Tensile strength of the Cu(Ti)/glass interface increased to about 60 MPa after annealing. The low resistivity and excellent adhesion resulted from Ti segregation at the film surface and the Cu(Ti)/glass interface. The segregated Ti atoms reacted with atmospheric oxygen at the surface and with oxygen in glass and/or from atmosphere at the interface, and formed a TiO2 layer at the surface and a TiO2 layer with a small amount of Ti2O3 and TiO at the interface. The layers were non-crystalline. Columnar grains in the alloy films were seen to enhance Ti segregation and subsequent Cu grain growth. The Cu grain growth also contributed to low resistivity of Cu(Ti) alloy films

Genetic characterization of type A enterotoxigenic Clostridium perfringens strains

Clostridium perfringens type A, is both a ubiquitous environmental bacterium and a major cause of human gastrointestinal disease, which usually involves strains producing C. perfringens enterotoxin (CPE). The gene (cpe) encoding this toxin can be carried on the chromosome or a large plasmid. Interestingly, strains carrying cpe on the chromosome and strains carrying cpe on a plasmid often exhibit different biological characteristics, such as resistance properties against heat. In this study, we investigated the genetic properties of C. perfringens by PCR-surveying 21 housekeeping genes and genes on representative plasmids and then confirmed those results by Southern blot assay (SB) of five genes. Furthermore, sequencing analysis of eight housekeeping genes and multilocus sequence typing (MLST) analysis were also performed. Fifty-eight C. perfringens strains were examined, including isolates from: food poisoning cases, human gastrointestinal disease cases, foods in Japan or the USA, or feces of healthy humans. In the PCR survey, eight of eleven housekeeping genes amplified positive reactions in all strains tested. However, by PCR survey and SB assay, one representative virulence gene, pfoA, was not detected in any strains carrying cpe on the chromosome. Genes involved in conjugative transfer of the cpe plasmid were also absent from almost all chromosomal cpe strains. MLST showed that, regardless of their geographic origin, date of isolation, or isolation source, chromosomal cpe isolates, i) assemble into one definitive cluster ii) lack pfoA and iii) lack a plasmid related to the cpe plasmid. Similarly, independent of their origin, strains carrying a cpe plasmid also appear to be related, but are more variable than chromosomal cpe strains, possibly because of the instability of cpe-borne plasmid(s) and/or the conjugative transfer of cpe-plasmid(s) into unrelated C. perfringens strains. © 2009 Deguchi et al