- 著者
- Naoto Takahata Yama Tomonaga Yuichiro Kumamoto Masatoshi Yamada Yuji Sano
- 出版者
- GEOCHEMICAL SOCIETY OF JAPAN
- 雑誌
- GEOCHEMICAL JOURNAL (ISSN:00167002)
- 巻号頁・発行日
- vol.52, no.2, pp.211-217, 2018-03-30 (Released:2018-04-19)
- 参考文献数
- 24
- 被引用文献数
- 1 21
In this work we report tritium concentrations determined in seawater samples collected offshore of Fukushima in the northwestern Pacific Ocean, immediately after the Fukushima Dai-ichi Nuclear Power Plant (F1-NPP) accident. We found surface seawater to have high concentrations of tritium (3H) and cesium-137 (137Cs) with respect to the concentrations expected for the investigated region. Tritium concentrations were up to six times the pre-accident level. However, these concentrations were found to be relatively low compared to those of 137Cs and 129I. This is most likely because of the very low production ratio of tritium to 137Cs in the F1-NPP, and the inherently high background concentration of tritium in these environmental waters (mainly ascribed to global fallout from nuclear weapons tests conducted during the 1960s). The tritium distribution in surface seawater showed higher concentrations close to the shore and lower concentrations offshore. Higher tritium concentration areas had spread both northward and southward from the F1-NPP along the coast, indicating that large amounts of tritium were carried by coastal currents. A positive correlation was found to exist between 3H and 137Cs concentrations in the seawater. The calculated 3H/137Cs ratio was similar to the production ratio of these isotopes reported for the broken reactors in the F1-NPP, which indicates that both radionuclides might have originated from the F1-NPP. Direct emission of tritium to the ocean from the F1-NPP was estimated to be approximately 0.05 PBq immediately after the accident, which is much smaller than the total inventory in the environment.
- 著者
- Masatoshi YAMADA Masaki OHATA Daisuke KAKOI
- 出版者
- The Institute of Electronics, Information and Communication Engineers
- 雑誌
- IEICE Transactions on Information and Systems (ISSN:09168532)
- 巻号頁・発行日
- vol.E105.D, no.3, pp.565-577, 2022-03-01 (Released:2022-03-01)
- 参考文献数
- 35
In ball games, acquiring skills to change the direction becomes necessary. For revealing the mechanism of skill acquisition in terms of the relevant field, it would be necessary to take an approach regarding players' cognition as well as body movements measurable from outside. In the phase of change-of-direction performance that this study focuses on, cognitive factors including the prediction of opposite players' movements and judgements of the situation have significance. The purpose of this study was to reveal cognitive transformation in the skill acquisition process for change-of-direction performance. The survey was conducted for three months from August 29 to November 28, 2020, and those surveyed were seven university freshmen belonging to women's basketball club of M University. The way to analyze verbal reports collected in order to explore the changes in the players' cognition is described in Sect.2. In Sect.3, we made a plot graph showing temporal changes in respective factors based on coding outcomes for verbal reports. Consequently, as cognitive transformation in the skill acquisition process for change-of-direction performance, four items such as (1) goal setting for skill acquisition, (2) experience of change in running direction, (3) experience of speed and acceleration, and (4) experience of the movement of lower extremities such as legs and hip joints were suggested as common cognitive transformation. In addition, cognitive transformation varied by the degree of skill acquisition for change-of-direction performance. It was indicated that paying too much attention to body feelings including the position of and shift in the center of gravity in the body posed an obstacle to the skill acquisition for change-of-direction performance.
- 著者
- MASATOSHI YAMADA
- 出版者
- JAPANESE ECONOMIC ASSOCIATION
- 雑誌
- The Economic Studies Quarterly (ISSN:0557109X)
- 巻号頁・発行日
- vol.44, no.1, pp.41-53, 1993-03-19 (Released:2008-02-28)
- 参考文献数
- 16
This paper elucidates the question of whether production efficiency (in the weak sense) obtains in an optimally taxed economy, which is posed by the seminal paper of Diamond and Mirrlees. This paper presents a complete conclusion and a proof for that the (desirability of) production efficiency holds, except (i) a not interesting case where private production is wholly less efficient than public production, or (ii) a case where some good(s) is exempt from tax imposition.