著者
Atsushi IKEDA Tetsuo SUEYOSHI Norikazu MATSUOKA Takemasa ISHII Youhei UCHIDA
出版者
The Association of Japanese Geographers
雑誌
地理学評論 (ISSN:13479555)
巻号頁・発行日
vol.80, no.5, pp.259-271, 2007-04-01 (Released:2010-03-12)
参考文献数
32
被引用文献数
1 1

Present-day distribution and ongoing degradation of permafrost were evaluated by geophysical means in the source area of the Yellow River, located at the northeastern margin of the Tibetan Plateau. Seismic, electrical and/or thermal soundings were undertaken at 15 sites between 3260m and 4790m ASL in 2003-2005. High P-wave velocities (>2kms-1) and relatively high DC resistivities (650-1100Ωm) below a thin uppermost layer show that permafrost 10-30m in thickness occurs above 4300m ASL. In contrast, low P-wave velocities (<1kms-1) throughout the uppermost ten to fifteen meters of sediments indicate that permafrost is absent below 4000m ASL. On widespread alluvial plains between 4200m and 4300m ASL, some sites show subsurface intermediate P-wave velocities (1.5-1.7kms-1) and low resistivities (30-140Ωm) indicating the presence of unfrozen-saturated sediments, while others show high DC resistivities possibly indicating the presence of permafrost. Negative values of the mean annual ground surface temperature (MAST) also indicate widespread permafrost only above 4300m ASL under the present climatic condition. Assuming that the inter-annual variation in MAST follows that in the mean annual air temperature, permafrost is estimated to have significantly thawed on the alluvial plains at 4200-4300m ASL during the last half-century.
著者
Toshirou Ono Atsushi Usami Satoshi Nakaya Keisuke Maeba Yasunori Yonejima Masanori Toyoda Atsushi Ikeda Mitsuo Miyazawa
出版者
公益社団法人 日本油化学会
雑誌
Journal of Oleo Science (ISSN:13458957)
巻号頁・発行日
pp.ess15098, (Released:2015-09-15)
被引用文献数
1

Enterococcus faecalis is one of the major lactic acid bacterium (LAB) species colonizing the intestines of animals and humans. The characteristic odor of the volatile oils obtained from both the liquid medium after incubation (MAI) and liquid medium before incubation (MBI) in the cultivation process of E. faecalis was investigated to determine the utility of the liquid medium. In total, fifty-six and thirty-two compounds were detected in the volatile oils from the MAI (MAI oil) and MBI (MBI oil), respectively. The principle components of MAI oil were 2,5-dimethylpyrazine (19.3%), phenylacetaldehyde (19.3%), and phenylethyl alcohol (9.3%). The aroma extract dilution analysis (AEDA) method was performed using gas chromatography-olfactometry (GC-O). The total number of aroma-active compounds identified in the volatile oil from MBI and MAI was thirteen compounds; in particular, 5-methyl-2-furanmethanol, phenylacetaldehyde, and phenylethyl alcohol were the most primary aroma-active compounds in MAI oil. These results imply that the industrial cultivation medium after incubation of E. faecalis may be utilized as a source of volatile oils.