大陆走滑地震断层参数的标定

通过应用简单的位移-深度函数,并假定“孕震区的基底并非发生了粘性张弛而产生,而是在介质(该介质在破裂处或邻近破裂处仍保持应力状态)中转变为稳定滑动的结果“,我们解决了弹性位错模型预报地震与平均同震滑动随着破裂长度的增加而增加的观测情况之间长期存在的矛盾。最终结果模型含有在地震尺度的整个波谱上地震具有自相似性的概念。     

由帕克菲尔德圣安德烈斯断层深部观测台钻井点主动源监测得到的震前速度变化

测量地震活跃断层区内的应力变化一直是地震学长期探寻的目标。在此我们指出,利用在圣安德烈斯断层深部观测台(SAFOD)钻孔点进行的井间主动源试验所得的地震波波速对应力的依赖性就可测量到这种应力变化。在两个多月的时间里,我们观测到沿着地下固定路径传播的S波走时变化(几微秒)与气压变化之间存在非常好的负相关性。我们还发现在走时数据中有两次很大的偏移,这两次偏移的时间与两个预计在圣安德烈斯断层深部观测台会产生最大同震应力变化的地震的时间吻合。有趣的是,这两次偏移分别在地震事件之前约10小时和2小时的时间开始,说明它们可能与早期实验室研究(Braceetal,1966;Scholz,1968)观测到的破裂前应力导致的裂纹性质改变有关。     

The overlooked role of the ocean in mercury cycling in the Arctic

The rapid and high bioaccumulation of mercury in marine mammals and its spatial and temporal variations have been a major puzzle in the Arctic. While extensive efforts have been focussed on the monitoring and chemistry of atmospheric mercury depletion events, a recent mass budget estimate of mercury in the Arctic suggests that we have overlooked the role of the ocean itself. Only through focussed studies on Hg dynamics in the Arctic Ocean under a changing climate are we going to understand what the risk of mercury is to those marine ecosystems and the people who rely on them.     

Seasonal closures as a measure of trawling effort control in two Mediterranean trawling grounds: effects on epibenthic communities

Within the framework of ecosystem-based management, we focused on the use of seasonal closures as effective measures to minimise the degradation of benthic communities by trawling. These closures imply the complete cessation of trawling fleet activity and are commonly used in the Mediterranean to reduce the annual fishing effort, with the ultimate goal of effective resource management. In this study, we aimed to investigate how epibenthic communities respond to seasonal closures. The potential benefits of short-term annual closures in two Mediterranean fishing grounds were evaluated by analysing changes in community structure and composition that were linked to the closure. A decrease of faunal abundance was observed with the resumption of fishing activity after the closure at both fishing grounds. Remarkably, results indicated that some large and mobile fauna were able to respond to these closures. We concluded that the currently planned closures are too short to benefit benthic communities.     

利用C，N稳定同位素分析法鉴别家猪与野猪的初步尝试

采用动物考古学和分子生物学的研究方法探索家猪的起源已取得丰硕的成果,但如何科学鉴别驯化初期的家猪,至目前为止一直缺乏有效的研究思路和方法．与野猪的食物主要源自自然环境相比,家猪的食物则更容易受人类饲喂活动的影响,故此,理论上,探索猪群间的食物结构差异,了解人类的饲喂活动对猪食物的影响,可望科学地辨别家猪与野猪．对山东后李文化时期（约8500～7500年前）小荆山遗址的人骨以及月庄遗址的动物骨进行了C,N稳定同位素分析,探索猪群食谱差异,并通过与先民以及其他动物的同位素数值比较,尝试科学地鉴别家猪与野猪．先民的δ^13 C（平均值-17．8‰±0．3‰和δ^15 N（平均值9．0‰±0．6‰）表明,先民虽已开始从事粟作农业,但粟作农业在人类的生活方式中尚不占主导地位（因为粟类植物是一种典型的C4植物）,先民还主要以采集、狩猎或驯养家畜为生．牛的δ^13 C值（-16．1‰）和δ^15 N值（6．9‰）,表明其食物主要以C3类植物为主,兼具少许C4类植物．与牛相比,鱼的δ^13 C值（-24．9‰）更低而和δ^15 N值（8．8‰）更高,显示出欧亚大陆淡水鱼的同位素特征．依据δ^13 C值和δ^15 N值的不同,猪可分为3组：A组,由两头猪组成,具有低的δ^13 C值（-18．1‰,-20．0‰）和δ^15 N值（4．7‰,6．0‰）;B组,仅有一头猪,具有最高的δ^13 C值（-10．6‰）和居中的δ^15 N值（6．4‰）;C组,仅有一头猪,其δ^13 C值（-19．0‰）较小而δ^15 N值（9．1‰）最高．现代或古代野猪骨的C,N稳定同位素分析研究已经表明,野猪主要以C3类植物为主,其δ^15 N值更接近于食草类动物而远离食肉类动物．通过与小荆山遗址先民、野猪及河南西坡遗址（仰韶文化,6000—5500年前）和康家遗址（龙山文化,4500～4000年前）家猪同?     

冰岛裂谷北部阿斯基亚火山之下岩浆运动引起的下地壳地震

裂谷中的下地壳层通常由于高温而呈韧性,火山岩浆活动会引发地震。冰鸟中大西洋裂谷的特点是热流高,大量岩浆聚集成高达25～30km厚的地壳,在上部8km内常发生地震。2006年7～8月在冰岛北部裂谷带阿斯基亚火山周围布设了20台地震仪进行观测,记录到位于脆韧性边界1700次震源深度为7～8km的上地壳地震;还记录到多数以震群形式发生在其他非震层的下地壳内和完全非震层的中地壳之下14～26km的100个M1〈1．5级小地震。在2007年7～8月的重复测量中,更是观测到2倍以上的下地壳地震事件。大地测量和重力数据显示,在阿斯基亚火山下存在熔岩流,当熔岩从岩浆房通过地壳流向阿斯基亚火山的过程中引发地震,也表明在活动裂谷带中岩浆在张开的岩脉中运移几米距离可引发爆裂。     

Preliminary attempt to distinguish the domesticated pigs from wild boars by the methods of carbon and nitrogen stable isotope analysis

Despite great achievements in the origins of domestic pigs made by the methods of zooarchaeology and molecular biology, how to scientifically distinguish the domesticated pigs from wild boars during the early stage of pig domestication is still poorly understood. Compared to wild boar’s diets which come from the natural environment, the diets of domestic pigs are more easily influenced by human feeding activities. Therefore, in principle, exploration of the dietary differences among pigs and under-standing the impact on pig diets fed by humans can have great potential to differentiate between wild boars and domesticated pigs. To reveal dietary differences among pigs and distinguish the domesticated pigs from wild boars based on comparison with the diets of humans and other animals, we analyzed the carbon and nitrogen stable isotopes of human bones from Xiaojingshan Site and animal bones from Yuezhuang Site, both of which belong to Houli Culture in Shandong Province and date to about 8500-7500 years ago. The mean δ¹³C value ((−17.8 ± 0.3)‰) and δ¹⁵N value ((9.0±0.6)‰) in human collagen indicate that although millet agriculture began it was not the main subsistence strategy as millets are typical of C₄ plants and that humans made a living mainly by gathering, hunting or raising some domesticated animals. The δ¹³C value (−16.1‰) and δ¹⁵N value (6.9‰) in the bovine suggest that C₃ plants were dominant in its diet with some C₄ plants complemented. The fish has lower δ¹³C value (−24.9‰) and higher δ¹⁵N value (8.8‰) than the bovine, which is the characteristic of the isotopic values from Eurasian freshwater fish. Based on the differences in carbon and nitrogen isotope values, the pigs can be divided into three groups. A group, composed of two pigs, has low δ¹³C values (−18.1‰, −20.0‰) and low δ¹⁵N values (4.7‰, 6.0‰). B group, only one pig, has the highest δ¹³C value (−10.6‰) and mediate δ¹⁵N value (6.4‰). As for the C group, also only one pig, low δ¹³C value (−19.0‰) and the highest δ¹⁵N value (9.1‰) are observed. Previous studies on the stable isotopes from modern or ancient wild boars’ bones have suggested that C₃ plants are predominated in their diets and that their δ¹⁵N values are close to those in herbivores and far from those in carnivores. Based on the comparison with the isotope values from humans, the wild boars and the domestic pigs from Xipo Site in Henan 6000-5500 years ago and Kangjia Site in Shaanxi 4500-4000 years ago, we conclude that A pig group belongs to wild boars while B and C groups can be attributed to domesticated pigs. Supported by Max-Planck Society and Chinese Academy of Sciences, Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KJCX3.SYW.N12), National Natural Science Foundation of China (Grant No. 40702003) and President Funding of Graduate University of Chinese Academy of Sciences     

Design of controlled elastic and inelastic structures

One of the founders of structural control theory and its application in civil engineering,Professor Emeritus Tsu T.Soong,envisioned the development of the integral design of structures protected by active control devices.Most of his disciples and colleagues continuously attempted to develop procedures to achieve such integral control.In his recent papers published jointly with some of the authors of this paper,Professor Soong developed design procedures for the entire structure using a design-redesign proce...