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We analyzed the major element composition of volcanic glass shards in drift pumice clasts sampled from the Japanese coast before the 2021 eruption of Fukutoku-Oka-no-Ba (FOB). Consequently, it has been explained that the source volcanoes of some drift pumice clasts are Shikotsu, Toya, Towada, Hakone, Aso, Aira, Ata, Baegdusan volcanoes, and submarine volcanoes FOB and NNE of Iriomotejima (SVI). In particular, drift pumice clasts estimated from the Aira volcano were found in broad areas from the Amami-Oshima to the Shimokita Peninsula, the southern and northern limits of our sampling sites, respectively. Furthermore, the Aira-Tn tephra, erupted from Aira volcano, forming a wide pyroclastic flow plateau in the southern part of Kyushu Island. Therefore, we interpreted that the reworking process of pyroclastic flow deposits is one of the major mechanisms of the continuous supply of pumice clasts into the sea, regardless of whether volcanic activity continues. In addition, the presence of drift pumice clasts from the FOB and SVI suggests that pumice clasts from a single submarine volcanic eruption can remain on the coast for at least several tens to a hundred years.

Residues from foraminiferal research samples from the MD01-2421 core collected off the Kashima coast, East Japan were used for cryptotephra detection. The esidues were carefully divided to maintain the foraminiferal community composition in the samples. As a result, data from 419 volcanic glass shards in the deposits from the top of the core to a depth of 9.5 cm were obtained, and cluster analysis was performed after normalizing the datasets. In one of the clusters with sample properties ranging from rhyolite to dacite, volcanic glass shards could be correlated to the As-A tephra that erupted from Mt. Asama, Central Japan in 1783 AD.

原著, リスクとは、私たちの毎日の行動に密接に結びつく、身近でかつ厄介な存在である。とりわけ、会社などの組織で物事を決定する際には、リスクは必ず検討される重要な要素である。そこで、本研究では、リスクに関する集団意思決定が、集団極化に及ぼす影響を検討することを目的とした。実験では、これまでのリスク研究で行われてきた個人と集団の比較に加え、対面条件と非対面条件、正と負の報酬という2つの統制条件を設け、個人と集団それぞれの意思決定を元にリスク回避度を測定した。その結果、リスクに関する集団意思決定を行った場合、集団の意思決定は個人の意思決定よりもリスク回避的に極化すること、負の報酬において極化が顕在化すること、対面状況と非対面状況では回避度に差が見られないことが明らかになった。しかしながら、本実験では非対面状況における集団討議の相互作用余地が少なかったことから、チャットやテレビ電話などを用いた、より自由度のある決定方法を用いて再検討を行う必要性が示唆された。, A risk is a familiar and awkward presence that closely links our daily behavior. Especially when we decide things in organizations such as company, the risk is an important factor to be considered. The purpose of this study was to examine the effects of decision making under risk on group polarization. In the experiment, setting up three control conditions, individuals/groups, face-to-face/non-face-to-face and positive/negative remuneration, the individual and group risk averse were determined. The results indicated that group decision making was risky sifted compare to the individual’s one, especially it was shown at the negative remuneration. Furthermore, this study also revealed that there was no difference of the risk averse between face-to-face and non-face-to-face. However, it was pointed out that the experiment design of non-face-to-face made it difficult to interact during the group discussion. Therefore, further consideration will be needed with using more flexible decision making design such as a web chat and a videophone.

Supplemental material, supplemental_2 for Reporting on the level of validity and reliability of questionnaires measuring Katakori severity: A systematic review by Kaori Aoki, Toby Hall and Hiroshi Takasaki in SAGE Open Medicine

新規な第四級アンモニウムシランカップリング剤であるヨウ化N-アリル-N-デシル-N-メチル-N-トリメトキシシリルプロピルアンモニウム(10-I)が多菌種バイオフィルムモデルに対して発揮する抗菌活性を調べる実験を施行した。上記モデルにおけるバイオフィルム形成初期を実験系に用いることで、口腔内プラーク様のバイオフィルムが固相表面に形成される状況を模倣させた。カバーグラスを濃度800ppmの10-I溶液に1時間浸漬して表面修飾処理を行い、上記のバイオフィルムを形成させた。コロニー形成単位(CFU)を計数した結果、10-I処理を行った群では対照群に対してCFUが80%減少したことから、10-Iが強い抗菌活性を有することが実証された。10-Iによる表面修飾処理は、常在菌に関連する歯科疾患のみならず誤嚥性肺炎などの全身合併症を予防低減する効果的な方法となることが当結果から示唆された。

Diatom fossil analysis was carried out in order to reveal Holocene paleoenvironment in the SW part of the Sea of Okhotsk using the quarified piston core HS97,P1 recovered off Shiretoko Peninsula, eastern Hokkaido. It should be emphasized that there are very few investigations for diplomatic problems even though oceanographic factors can be expected to reflect global environmental change and affect human activities. As the results, we recognized that occurrence of Thalassionema nitzschioides and Neodenticula seminae, both of which indicate high productivity, increased toward the top of the core, whereas those of ice-related, allochthonous and brakish species decreased. Besides we ditected the cyclic occurrence of warm water species Fragilariopsis doliosus as a sensitive indicator of the Soya Warm Current in spite of low frequencies. Concequently we described the following scenario based on the obtained results : 1)There has existed sea ice concentration off Shiretoko for the last 7400 years with its intensity diminishing, 2)The cyclic occurrence of F. doliosus is likely to tuned to the pulses of the Tsushima Warm Current in the Sea of Japan during Holocene outlined in Koizumi (1987,1994), in addition to the time-space distribution of warm molluscan fossils such as Meretrix lusoria in some shell mounds around eastern Hokkaido., タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 1998 (平成10)年度