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A new fossil diatom species, Paralia kawasumii Sato sp. nov., has been found in upper Holocene coastal sediments of the central Ise Plain, central Japan. Detailed examination by light and scanning ...

High-resolution seismic profiles, combined with the integration of published drilling data, provide a detailed paleoenvironmental history of Lake Yamanaka (Fuji Five Lakes, Japan). This study presents a detailed analysis of the different depositional stages of the area currently occupied by Lake Yamanaka (floodplain wetland, river and lake). From ca. 5500 cal yr BP to ca. 5050 cal yr BP, the Yamanaka basin was occupied by floodplain wetlands. During that period, the landscape was very stable and erosion on northeastern flank of Mt. Fuji was relatively limited. From ca. 5050 cal yr BP to ca. 3050 cal yr BP, the water level increased and the floodplain wetlands became a lake. From ca. 3050 cal yr BP to ca. 2050 cal yr BP, the water level progressively decreased, leading to a reduction in lake extent. During this lowering of the lake's water level, a 1 km2 mass-transport deposit modified the physiography of the lake floor. From ca. 2050 cal yr BP to ca. 1050 cal yr BP, the lake disappeared and a river flowing towards the northwest occupied the depression. Ponds occupied morphological lows formed by mass-transport deposits. From ca. 1050 cal yr BP to the present day, the lake water level rose again, connecting the ponds with the main lake. Since then, the lake water level has continued to rise to the current level. Lake water level fluctuations are the results of several factors that could be interconnected: (i) changes in precipitation rates; (ii) margin destabilization (the Yamanaka mass-transport deposit), (iii) changes in river inlets and therefore variation in water supplies, (iv) volcanic eruptions (scoria fall-out and lava flows) and (v) changes in vegetation cover. This study highlights the importance of coupling sediment cores and high-resolution seismic reflection profiling to identify lateral variation and modification of sedimentary inputs through time.

小川原湖東岸に位置する野口貝塚周辺において，地形環境の変遷を明らかにするために遺跡発掘時のトレンチ断面観察，機械ボーリングを実施し，堆積物の放射性炭素年代測定，粒度分析，珪藻分析を行った。野口貝塚の南側に位置する開析谷は，褐色と暗色を呈する砂層の互層からなる層厚約12 mの堆積物により充填される。この砂層は後氷期の海進に伴って形成された海水～汽水環境の溺れ谷に，背後の段丘崖や開析谷から間欠的にもたらされた土砂であり，その堆積は8,400～7,150 cal BPの間に急速に行われたことが明らかになった。野口貝塚周辺の人々は，縄文海進に伴って湖岸部での土砂の堆積が急速に進む環境の中で生活を営んでいたと考えられる。

Study of prehistoric to medieval-age tsunami deposits along a riverbank site near the eastern Nankai Trough, central Japan, show that, not only did Tokai earthquakes occur with a higher frequency than previously thought, but that contemporaneous ruptures of the Tokai and Nankai fault segments were also more common. The site revealed a ∼1-km long coast-normal cross section of the strand plain and exposed four sandy tsunami deposits, each of which indicates inundation over 2 km inland of the coast. Radiocarbon dating of previously studied and newly discovered deposits in the region indicates a shorter recurrence time for Tokai earthquakes and clarifies their linkage with Nankai earthquakes. We attribute the younger two tsunami deposits to the 1498 and 1096 CE Tokai earthquakes. The older two deposits confirm the occurrence of the Tokai earthquakes in 887 CE and in the latest 7th century. These events are not reliably recorded in historical documents in the Tokai region but were noted in the Nankai area. The 887 CE earthquake likely represents a full-length rupture of the Tokai and Nankai segments, as was the case for the 1707 CE earthquake. Integrated with the previous studies, these new results show that nine Tokai earthquakes occurred over the last 1300 years, the oldest in the latest 7th century, and in 887, 1096, 1361, 1498, 1614, 1707, 1854 and 1944 CE. Recalculated recurrence intervals range from 90 to 265 years. Except for the 1498 Meio Tokai earthquake, the Tokai earthquakes occurred simultaneously with Nankai earthquakes.

The AD 1498 Meio earthquake (M8.2 similar to 8.4) that occurred along the eastern Nankai trough, and the tsunami generated by the earthquake, induced major geomorphological and social changes along the Pacific coast of central Japan. Geological coring along the palaeochannel of the Hamana River, southern Shizuoka Prefecture, revealed that its river mouth was abruptly closed followed by a rapid change from river to marsh environment at the end of the 15th century. It is suggested that mass transport of sediments by the Meio tsunami forced the closure of the river mouth. The latter environmental change happened synchronously with the sudden decline of a famous port town, Hashimoto, formerly flourishing along the middle reach of Hamana River. Closure of the water route connecting Hashimoto with the Pacific Ocean potentially led to the decline and abandonment of the port town.

This study investigates whether people entrain their body sway in everyday face-to-face communication. Interpersonal entrainment has been observed under experimental conditions, but not in daily life. We used wearable sensors to measure individual body vibration and face-to-face interactions in daily life. The observation included at least 100 participants from each of seen organization over a period of two to three months. We carried out measurements over a period of two to three months for each organization. It was found that the body vibration frequencies of two participants become more closer in face-to-face situations than in non-face-to-face situations. This result suggests that interpersonal entrainment of body sway occurs in everyday face-to-face communication.

越後平野中部を対象として, 層相や土砂の堆積速度の地域的差異を検討し, 完新世後期における河川供給土砂の堆積場の変化と地形発達を明らかにした. 同地域では縄文海進時に内湾が形成され, 7,000～6,000yrsBPには湾奥部にまで海水の影響が及んだ. 縄文海進高頂期以降, 内湾は縮小と拡大を繰り返しながら, 信濃川の供給土砂によって徐々に埋積された. 土砂の堆積場の中心は, 完新世後期を通じて海側に移行する傾向が認められ, 4,000yrsBP以降には臨海部における土砂の前方付加や砂丘の形成が集中的に進行した. 一方, 堆積場の中心から外れた内陸側の氾濫原においては, 土砂の垂直的な堆積が徐々に進行し, その過程においては河川の洪水による土砂の堆積が少ない1,400～1,000yrsBPの「安定期」と, 土砂の堆積が活発化した1,000～800yrsBPの「堆積期」が認められた. 現在, 西川と中之口川の間の氾濫原にみられる自然堤防群の大半は, 1,000～800yrsBPに生じた河川の洪水による土砂堆積の活発化にともなって形成された.

中部日本の濃尾平野を対象として,約3,000～2,000 yr BPにおける海岸線の変化とその要因を明らかにするために,ハンドボーリング調査,堆積物の14C年代測定,珪藻分析などを行った.濃尾平野では縄文海進最盛期以降,海岸線が海側に前進し,内湾の縮小が進行した.特に約3,000～2,000 yr BPには,海岸線の前進と低地の拡大が急速であった.この原因は,約3,000～2,500 yr BPにおける相対的海水準の低下と,約2,300～2,100 yr BPに生じた土砂供給の増加と考えられる.約2,300～2,100 yr BPにおける三角州前置層の堆積量は,1.1～1.4km3と推定され,これは約3,000～2,300 yr BPにおける前置層の堆積量(1.1～1.5km3)に匹敵する. 2,300～2,100 yr BP頃における堆積活動の活発化は,中部日本や西日本の多くの平野でも確認されており,気候変化に伴う豪雨の増加といった広域的な原因を持つ可能性がある.

完新世後期の濃尾平野における土砂堆積域の変遷について,低地の地形・地質と遺跡の分布や遺物の検出状況をもとに検討した.濃尾平野では縄文時代中期後葉(4,300yrs BP)以降,木曾川扇状地東部を中心に遺跡が分布するようになり,縄文時代後期末(3,000yrs BP)と弥生時代前期末(2,200yrs BP)の2度の画期を経て,西側と南側の地域にその分布域を段階的に拡大させた.各遺跡では,地表面下2m以浅の黒色有機物層やシルトを主体とした細粒堆積物層から遺物が出土しており,遺跡が立地して以降,洪水による堆積物の供給を受けにくい環境が継続したことが推定された.これらから,濃尾平野では完新世後期に木曾川の主流および土砂の堆積域が低地東部から西部へと移行するとともに,堆積環境の安定域が西部や南部へ拡大したことが考えられる.このような変遷過程は,養老断層を境に沈降する西下がりの傾動運動と対応しており,その影響を受けたものと推定される.また,縄文時代晩期(3,000yrs BP)以降における木曾川の顕著な西流傾向と海側の地域における土砂の集中的な堆積は,「弥生の小海退」に相当する海岸線の海側への急速な前進のおもな要因となったと考えられる.

濃尾平野北東部において,典型的な埋積浅谷が発達する門間沼遺跡・馬引横手遺跡を対象として,地層断面の観察および記載,堆積物の14C年代値の測定を行い,埋積浅谷の発達過程を明らかにした.その結果,濃尾平野北東部では,浅谷が約3,000～2,400年前に形成され,約2,400～2,200年前に埋積されたことが明らかとなった.さらに,周辺遺跡の地形・地質データを加えて,浅谷形成と周辺地域の地形変遷の関係について検討した.濃尾平野北東部では,約3,000年前以前には洪水による堆積が活発に行われたが,約3,000年前以降は洪水の影響が少ない安定した環境へと変化し,浅谷はこのような堆積環境の移行過程で形成されたことが明らかとなった.

Human communication contains not only explicit factors like the meaning of utterance but also implicit factors like body motion. We presume that the synchronization of body motions has a long time with an increased consensus degree during consensus building, and conducted a conversation task to verify this presumption. The present study focuses on the positive correlation of head motions as an indicator of body motion synchronization and questionnaire evaluation as an indicator of consensus building to analyze the relationship between head motion synchronization and consensus degree. Our experimental results showed that two participants' head motions synchronized with each other and the synchronization time of the head motions has a long time during the period of high consensus evaluation. The results suggest that the synchronization period has a long time as consensus degree increases in the process of consensus building.

In order to clarify the relationship between human social interaction and mental health, we measured face-to-face communication pattern for a few months and conducted a questionnaire on mental health in two organizations in real world. Face-to-face interaction data were measured using wearable sensing system in two organizations in Japan. We extracted some feature values from those two kind data and investigated correlation between them. In this study, we reconsidered social network centrality which means the connection strength between people. We classified the group size of simultaneous interaction and duration of interaction. As results, we found that these factors affected the correlation coefficients between face-to-face interaction and degree of stress.

In order to explore the relationship between human social interaction and mental health, we investigated the correlations between the amount of face-to-face contact time and quantified mental health. Social interaction data were obtained by wearable sensing system for two organizations in Japan. In this study, we regarded face-to-face contact between individuals as social interaction. The mental health of individuals was measured by psychological questionnaire. We found that the social behavioral property of individuals tended to reflect quantified stress in both organizations. The results suggest the possibility that people who experience large amounts of social interaction tend to have less stress.

Hepatocellular carcinoma (HCC) rarely metastasizes to the oral and maxillofacial regions. To our knowledge, only 24 cases have been reported. Two additional cases of metastatic HCC in the oral and maxillofacial regions are reported and related cases reported in the literature are reviewed. A 47-year-old man complaining of swelling of the right TMJ and a 63-year-old man complaining of buccal swelling, in both cases, the primary lesion was diagnosed only after diagnosis of the oral and maxillofacial lesion.

Seven gouge cores in the middle Sepik Plain (northern Papua New Guinea) were bored to clarify the depositional age and the chemical characteristics of the tropical peat. The weakly-acidic peat layer (3–4 m thick) is distributed around the south bank of the Blackwater Lakes. The peat layer consists mainly of sago palm and grass remains within a mineral matrix of very fine sand and clay. Radiocarbon dating indicates that the peat’s formation had commenced by 3,710–3,560 cal BP. Nitrogen and exchangeable potassium reach their highest values in the upper 60 cm of the peat column. Conversely, exchangeable sodium, calcium and magnesium, as well as carbon, increase their values with depth in the peat. These differences in the exchangeable cations’ contribution suggest changes in the plant species, which were decomposed during the peat’s formation.