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  • Author or Editor: K. Hayashi x
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Understanding the relationship between the distribution of organisms and their environment is important for regional conservation planning. While most herpetofaunal community studies address environmental influence on species richness, few studies describe environmental influence on species composition at geographic scales. Field surveys of herpetofauna were conducted during 1994-2000 in Tochigi Prefecture, which covers ca. 6400 km_ of mainland Japan and includes a wide range of elevation, annual mean temperature, and human population densities. We evaluated whether (i) regional herpetofauna are distributed along a gradient of climate and elevation, as well as land cover and land use, and (ii) 'climate/elevation' and 'landcover' variables differ in their relative contribution. Ordination indicated a strong geographic gradient in species composition that was correlated with climate, elevation, land cover and land use. Reptiles were strongly influenced by land cover and land use (residential, agricultural, and forested area), while amphibians responded to all gradients (climate, elevation, and land cover and land use). All species with declining populations listed in the Prefectural Red Data Book were associated with mid-elevation regions, where anthropogenic modification is most intensive. All exotic species were strongly associated with anthropogenic gradients.

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Abstract  

A versatile system has been developed for the TL-reader of geological samples by using a personal computer system combined with a ceramic heater and a photon counting technique. A handy heater stack consisting of four ceramic heater plates was operated to ensure constant heating rate by applying phase-control circuit up to 400°C to a normal laboratory AC-power supply in order to obtain the TL-results as quantitatively as possible. From the results of the artificially irradiated quartz, a small amount of sample like 5 mg was verified to be applicable to obtain useful geochronological and geothermal information.

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Abstract  

The stability constants (β 1) of iodide ion-pairs of trivalent f-block element ions (lanthanoids Ce, Eu, Gd, Tb and Tm, and actinoid Am) were determined in the vicinity of pH 2.5 of mixed methanol/water solvent solutions of an ionic strength of 1.00 mol·dm−3 at 298±1 K. The values were less than 2. From the variation in distance between Eu3+ and I, which was calculated using a Born-type equation for Gibbs’ free energy derived from β 1(Eu), the Eu3+-I interaction was shown to be solvent-shared ion-pair formation when the mole fraction of methanol (X MeOH)≤0.40. In contrast, it was suggested that the interaction of Am3+-I changed from solvent-separated ion-pair to solvent-shared ion-pair with increasing X MeOH when X MeOH≤0.10, but remained as solvent-shared ion-pair in the range 0.16≤X MeOH≤0.40. Furthermore, β 2(Am) was measured in the range 0.31≤X MeOH≤0.40. It was also shown that the β 1 values of lanthanoids at X MeOH = 0.40, except for that of Gd(III), decreased with increasing atomic number.

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The melting transition of Ga and In was measured by using a nW-stabilized differential scanning calorimeter working in a magnetic bore. The magnetic effect on the thermometer was about 18 mK at 5 T, which was corrected for the measurement of the magnetic effect on the melting transition of Ga and In. The melting temperatures of Ga and In with the magnetic field of 5 T were obtained to be 8.3 and 10.2 mK, respectively higher than those without the magnetic field. These results show that the solid phase to be relatively more stable under the magnetic field. The calculated temperature shifts of the melting transition due to the magnetic field using the magneto-Clapeyron equation and the reference data of magnetic susceptibility were negative values for both Ga and In, being contradictory to the experimental results.

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Positron annihilation lifetime measurement and Fourier transform infrared spectrometry were applied to the study of temperature dependencies of free volume parameters and hydrogen bonds in segmented polyurethane, specially fabricated as a shape memory polymer. The variation of free volumes in amorphous region were correlated to that of hydrogen bonding and the shape memory mechanism of polyurethane is elucidated from a microscopic point of view. The relationship between free volume contents and the formation of hydrogen bonds significantly suggests that the shape memory occurs due to the configurational recovery of the microscopic regulation around urethane bundles of hard segment and consequent restoration of soft-segment in polyurethane.

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We have analyzed 16 elements and the radioactivity of 210Pb in a wood disk, across the annual rings to find out a promising tool for dendrochronology (chronology of wood) both for a Japanese wood, Cryptomeria japonica, and for an Indonesian rain forest wood, Alstonia, which does not form annual rings because of the relatively constant climate of the rain forest. As a result, only Mg concentration showed similar, smooth decreasing tendency in both wood species. The smooth change of the Mg concentration across the annual rings along with the growth suggested the possibility of the Mg concentration determination as a promising dendrochronological tool.

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A new method to measure heat flux and thermal expansion simultaneously with a temperature resolution of milli-Kelvin is presented to observe the multistage transitions. At least six thermal anomalies are observed between 402 and 403 K in BaTiO3 simultaneously in heat flux and thermal expansion in the cooling process. The correspondence of the anomalies observed in the two physical properties is excellent.

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For the assessment of a public impact caused by radionuclides released from nuclear facilities, a dynamic compartment model was developed for prediction of behavior of radioiodine in air, paddy field and rice plant system. The transfer coefficients among compartments were determined by some experimental data and assumptions for each chemical form of iodine. A verification of the model was carried out by some case studies.

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Abstract  

We developed a quantitative, real-time imaging system of labeled compounds in a living plant. The system was composed of CsI scintillator to convert β-rays to visible light and an image intensifier unit (composed of GaAsP semiconductor and MCP; micro channel plate) to detect extremely weak light. When the sensitivity and resolution of the image of our system was compared with that of an imaging plate (IP), the sensitivity of our system (with 20 minutes) was higher than that of an IP, with similar quality to that of an IP. Using this system, the translocation of 32P in a soybean plant tissue was shown in successive images.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: K. Tanoi, H. Matsue, H. Iikura, T. Saito, Y. Hayashi, Y. Hamada, H. Nishiyama, N. Kobayashi, and T. Nakanishi

Abstract  

We carried out instrumental neutron activation analysis (INAA) as well as k 0-based prompt gamma-ray analysis (k 0-PGA) to measure the amount of the elements in onions and studied whether the onions collected from different sites can be categorized based on the elemental concentration profile. Six elements (Na, Mg, Cl, K, Ca, Mn) and 3 elements (B, S, Cl) were measured by INAA and PGA in the onions grown in two districts, Hokkaido and Saga, in Japan, respectively. After principal component analysis, it was found that Cl was an important element to feature the producing districts of onions.

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