Oxygen, hydrogen, and carbon isotopic compositions in deep sea cherts, porcellanites, and coexisting carbonates from DSDP Legs 2, 3, 6, 7, 11, 14, 16, 17, and 20

Seventy four samples of DSDP recovered cherts of Jurassic to Miocene age from varying locations, and 27 samples of on-land exposed cherts were analyzed for the isotopic composition of their oxygen and hydrogen. These studies were accompanied by mineralogical analyses and some isotopic analyses of the coexisting carbonates. d18O of chert ranges between 27 and 39%. relative to SMOW, d18O of porcellanite - between 30 and 42%. The consistent enrichment of opal-CT in porcellanites in 18O with respect to coexisting microcrystalline quartz in chert is probably a reflection of a different temperature (depth) of diagenesis of the two phases. d18O of deep sea cherts generally decrease with increasing age, indicating an overall cpoling of the ocean bottom during the last 150 m.y. A comparison of this trend with that recorded by benthonic foraminifera (Douglas and Savin, 1975; http://www.deepseadrilling.org/32/volume/dsdp32_15.pdf) indicates the possibility of d18O in deep sea cherts not being frozen in until several tens of millions of years after deposition. Cherts of any Age show a spread of d18O values, increasing diagenesis being reflected in a lowering of d18O. Drusy quartz has the lowest d18O values. On-land exposed cherts are consistently depleted in 18O in comparison to their deep sea time equivalent cherts. Water extracted from deep sea cherts ranges between 0.5 and 1.4 wt %. dD of this water ranges between -78 and -95%. and is not a function of d18O of the cherts (or the temperature of their formation).

ケニアにおけるテロ関連暴力とその影響 -- 2014年6月のコースト・ンペケトニ事件を中心に

2011年10月のケニア国軍による南部ソマリアへの越境攻撃開始後、ケニアではアッシャバーブの報復攻撃とみられるテロが多発している。そのケニアで、2014年6月、ソマリア国境に近いンペケトニと呼ばれる一帯において大規模な住民襲撃事件が発生した。アッシャバーブがすぐに犯行声明を出したものの、ケニアのケニヤッタ大統領はアッシャバーブの犯行を否定し、「特定コミュニティを標的にしたエスニック・バイオレンス」だとの見解を表明した。ンペケトニ事件は、「悪化するテロ対ケニア政府による治安強化」というこれまでの図式に、いかなる波紋を投じたものだったのだろうか。本稿では、このンペケトニ事件を整理し、ケニア政府側の対応を追いながら、ンペケトニ周辺の土地問題と民族的分布との関係、与野党対立の現状、そしてケニアのインド洋沿岸を舞台に今も続く分離主義運動を中心に事件の背景を探り、今後の影響を考察する。

Effects of a defender on run-up velocity and ball speed when crossing a football

This study evaluated effects of defensive pressure on running velocity in footballers during the approach to kick a stationary football. Approach velocity and ball speed/accuracy data were recorded from eight football youth academy participants (15.25, SD=0.46 yrs). Participants were required to run to a football to cross it to a receiver to score against a goal-keeper. Defensive pressure was manipulated across three counterbalanced conditions: defender-absent (DA); defender-far (DF) and defender-near (DN). Pass accuracy (percentages of a total of 32 trials with 95% confidence limits in parenthesis) did not significantly reduce under changing defensive pressure: DA, 78% (55–100%); DF, 78% (61–96%); DN, 59% (40–79%). Ball speed (m·s−1) significantly reduced as defensive pressure was included and increased: DA, 23.10 (22.38–23.83); DF, 20.40 (19.69–21.11); DN, 19.22 (18.51–19.93). When defensive pressure was introduced, average running velocity of attackers did not change significantly: DA versus DF (m·s−1), 5.40 (5.30–5.51) versus 5.41 (5.34–5.48). Scaling defender starting positions closer to the start position of the attacker (DN) significantly increased average running velocity relative to the DA and DF conditions, 5.60 (5.50–5.71). In the final approach footfalls, all conditions significantly differed: DA, 5.69 (5.35–6.03); DF, 6 .22 (5.93–6.50); DN, 6.52 (6.23–6.80). Data suggested that approach velocity is constrained by both presence and initial distance of the defender during task performance. Implications are that the expression of kicking behaviour is specific to a performance context and some movement regulation features will not emerge unless a defender is present as a task constraint in practice.