- 著者
- HIROAKI SATO KYOHEI KAWAMURA KOJI HAYASHI HIROYUKI INAI TARO YAMAGUCHI
- 出版者
- The Anthropological Society of Nippon
- 雑誌
- Anthropological Science (ISSN:09187960)
- 巻号頁・発行日
- pp.1201250125, (Released:2012-01-27)
- 被引用文献数
- 4 19
We designed observational surveys of controlled foraging trips of Baka hunter-gatherers in Cameroon to verify the ‘wild yam question’—i.e. is it possible for human beings to live without agricultural products in a tropical rainforest?—and to examine their foraging lifestyle. We observed two 20-day trips during which no agricultural or commercial food except salt and pepper could be used. The first trip was conducted by six married couples in August, the short dry season, of the year 2003, and the second one by eight married couples in October, the rainy season, 2005. The Baka cooperators obtained 22 species and 43 vernacular names of food in all during both survey periods. No cooperators lost weight from any food shortage in both seasons. Energy intake per consumption-day was estimated at 2528–2865 kilocalories in the dry season, and at 2479–2777 kilocalories in the rainy season. Providing more than 60% of estimated energy intake in both seasons, wild yam tubers proved to be an essential food to enable a foraging life in tropical rainforests. From this survey we could find no evidence that it is impossible to live independently of agriculture in a tropical rainforest although it seemed that the cooperators paid a high energy cost to secure food, especially wild yam tubers. This study implies that a Paleolithic foraging lifestyle in the African tropical rainforest was very likely, although not easy, and that Paleolithic foragers may have been the ancestors of the present ‘pygmy’ hunter-gatherers.
- 著者
- Koji HAYASHI Ryo ISHII Tosihiki TAKAMIZAWA Shunichi SUDA Ryota AOKI Kana HAYASHI Atsushi KAMIMOTO Masashi MIYAZAKI
- 出版者
- The Japanese Society for Dental Materials and Devices
- 雑誌
- Dental Materials Journal (ISSN:02874547)
- 巻号頁・発行日
- pp.2023-073, (Released:2023-11-23)
- 参考文献数
- 29
This study aimed to evaluate the influence of surface pretreatment on the shear bond strength of resin luting cement to saliva-contaminated resin core foundation. The surface free energy (γS) of the adherent surfaces was examined. The two-way analysis of variance revealed that the surface pretreatment and storage conditions had a significant effect on the strength of the bond to resin core foundation. The γS values of the saliva-contaminated group were significantly lower than those of the other groups, and they tended to improve after surface pretreatment. The tendency of improvement in γS values differed depending on the type of pretreatment agents. Surface treatment with solutions containing functional monomers is effective in removing saliva contaminants from the resin core foundation surfaces and in creating an effective bonding surface for the resin luting cement.