Iron Emission Lines on the Galactic Ridge Observed with Suzaku

In order to elucidate origin of the Galactic Ridge X-ray Emission, we analyzed Suzaku data taken at various regions along the Galactic plane and studied their Fe-K emission line features. Suzaku resolved the Fe line complex into three narrow lines at ~6.4 keV,~6.7 keV and ~6.97 keV, which are K-lines from neutral (or low-ionized), He-like, and H-like iron ions, respectively. The 6.7 keV line is clearly seen in all the observed regions and its longitudinal distribution is consistent with that determined from previous observations. The 6.4 keV emission line was also found in various Galactic plane regions (b~0). Differences in flux ratios of the 6.4 keV/6.7 keV and 6.97 keV/6.7 keV lines between the Galactic plane and the Galactic center regions are studied and its implication is discussed.Comment: Accepted for publication in PASJ Suzaku 3rd special issu

Identifying Characteristics of the Agile Development Process That Impact User Satisfaction

The purpose of this study is to identify the characteristics of Agile development processes that impact user satisfaction. We used user reviews of OSS smartphone apps and various data from version control systems to examine the relationships, especially time-series correlations, between user satisfaction and development metrics that are expected to be related to user satisfaction. Although no metrics conclusively indicate an improved user satisfaction, motivation of the development team, the ability to set appropriate work units, the appropriateness of work rules, and the improvement of code maintainability should be considered as they are correlated with improved user satisfaction. In contrast, changes in the release frequency and workload are not correlated

High-temperature thermoelectric properties of the double-perovskite ruthenium oxide (Sr1−x_{1-x}Lax_x)2_2ErRuO6_6

We have prepared polycrystalline samples of (Sr$_{1-x}$La$_x$)$_2$ErRuO$_6$ and (Sr$_{1-x}$La$_x$)$_2$YRuO$_6$, and have measured the resistivity, Seebeck coefficient, thermal conductivity, susceptibility and x-ray absorption in order to evaluate the electronic states and thermoelectric properties of the doped double-perovskite ruthenates. We have observed a large Seebeck coefficient of -160 $\mu$V/K and a low thermal conductivity of 7 mW/cmK for $x$=0.1 at 800 K in air. These two values are suitable for efficient oxide thermoelectrics, although the resistivity is still as high as 1 $\Omega$cm. From the susceptibility and x-ray absorption measurements, we find that the doped electrons exist as Ru$^{4+}$ in the low spin state. On the basis of the measured results, the electronic states and the conduction mechanism are discussed.Comment: 6 pages, 4 figures, J. Appl. Phys. (accepted

Discrete mappings with an explicit discrete Lyapunov function related to integrable mappings

We propose discrete mappings of second order that have a discrete analogue of Lyapunov function. The mappings are extensions of the integrable Quispel-Roberts-Thompson (QRT) mapping, and a discrete Lyapunov function of the mappings is identical to an explicit conserved quantity of the QRT mapping. Moreover we can obtain a differential and an ultradiscrete limit of the mappings preserving the existence of Lyapunov function. We also give applications of a mapping with an adjusted parameter, a probabilistic mapping and coupled mappings.Comment: submitted to Physica

Ice thikness measurement on glaciers in Suntar Khayata, Eastern Siberia (A preliminary result)

第3回極域科学シンポジウム/特別セッション「これからの北極研究」11月28日（水） 国立極地研究所 2階大会議

Toxin Production by Aeromonas sobria in Natural Environments: River Water vs. Seawater

Aeromonas are water-borne pathogens. They are halotolerant, which means that they can survive in environments whose salt content corresponds to that of seawater (3.0% NaCl). However, the presence of Aeromonas in seawater is extremely rare compared with that in river water. In this study, we tested the ability of Aeromonas sobria to produce toxins in river water and seawater. First, we cultured A. sobria on skim milk agar plates supplemented with either river water (SARW) or seawater (SASW). The bacteria grew on both plates. A clear zone around the bacteria was generated in SARW. However, such a zone was not observed in SASW, suggesting that proteases were not generated in SASW. Subsequently, we cultured A. sobria in a nutrient broth supplemented with either river water (NRW) or with seawater (NSW), and examined the protease activity of their culture supernatants. The protease activity of the culture supernatant from NSW was extremely low compared to that from NRW. The immunoblotting analysis showed that serine protease (ASP) was not produced by the culture in NSW. By contrast, aerolysin-like hemolysin was produced in all conditions examined in this study. This indicates that the salinity of water is deeply involved in the production of ASP by A. sobria.</p

Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission

We have observed the diffuse X-ray emission from the Galactic center (GC) using the X-ray Imaging Spectrometer (XIS) on Suzaku. The high-energy resolution and the low-background orbit provide excellent spectra of the GC diffuse X-rays (GCDX). The XIS found many emission lines in the GCDX near the energy of K-shell transitions of iron and nickel. The most pronounced features are FeI K alpha at 6.4 keV and K-shell absorption edge at 7.1 keV, which are from neutral and/or low ionization states of iron, and the K-shell lines at 6.7 keV and 6.9 keV from He-like (FeXXV K alpha) and hydrogenic (FeXXVI Ly alpha) ions of iron. In addition, K alpha lines from neutral or low ionization nickel (NiI K alpha) and He-like nickel (NiXXVII K alpha), and FeI K beta, FeXXV K beta, FeXXVI Ly beta, FeXXV K gamma and FeXXVI Ly gamma are detected for the first time. The line center energies and widths of FeXXV K alpha and FeXXVI Ly alpha favor a collisional excitation (CE) plasma for the origin of the GCDX. The electron temperature determined from the line flux ratio of FeXXV K alpha / FeXXV K beta is similar to the ionization temperature determined from that of FeXXV K alpha /FeXXVI Ly alpha. Thus it would appear that the GCDX plasma is close to ionization equilibrium. The 6.7 keV flux and temperature distribution to the galactic longitude is smooth and monotonic,in contrast to the integrated point source flux distribution. These facts support the hypothesis that the GCDX is truly diffuse emission rather than the integration of the outputs of a large number of unresolved point sources. In addition, our results demonstrate that the chemical composition of Fe in the interstellar gas near the GC is constrained to be about 3.5 times solar.Comment: 11 pages, 19 figures. Accepted for publication in PASJ Suzaku Special Issue (vol. 59 sp. 1

Varicella-zoster virus ORF 58 gene is dispensable for viral replication in cell culture

<p>Abstract</p> <p>Background</p> <p>Open reading frame 58 (ORF58) of varicella-zoster virus (VZV) lies at the 3'end of the Unique long (U_L) region and its functional is unknown. In order to clarify whether ORF58 is essential for the growth of VZV, we constructed a deletion mutant of ORF58 (pOka-BACΔ58) from the Oka parental genome cloned into a bacterial artificial chromosome (pOka-BAC).</p> <p>Results</p> <p>The ORF58-deleted virus (rpOkaΔ58) was reconstituted from the pOka-BACΔ58 genome in MRC-5 cells, indicating that the ORF58 gene is non-essential for virus growth. Comparison of the growth rate of rpOkaΔ58 and recombinant wild-type virus by assessing plaque sizes revealed no significant differences between them both in MRC-5 cells and malignant melanoma cells.</p> <p>Conclusion</p> <p>This study shows that the ORF58 gene is dispensable for viral replication and does not affect the virus' ability to form plaques <it>in vitro</it>.</p