东哈萨克核爆炸产生的远震P波尾波中Rg散射成P波的证据

两个地震台阵记录的Degelen和Shagan河(东哈萨克)地下核爆炸产生的远震数据的分析表明,低频振幅比P/P尾波随爆炸源深度而明显变化。这组数据包括NORSAR和EKA台阵分别记录的22次Degelen爆炸数据(包括8个已公布爆炸点深度的数据)和40次Shagan河爆炸数据。根据这些台阵数据用最小二乘反演,分离震源项和接收项,推导的结果不受记录场地效应的影响。也比较了不同深度的相邻爆炸点的P波和P尾波,得到的结果几乎与传播路径效应无关。观测到对深度依赖的可能解释是由于震源区的不均匀性,爆炸激发产生的Rg散射成P波是远震P波的主要来源。观测的P尾波持续时间表明散射可能发生在浅地壳的大区域,因此,可将尾波的稳定性当作爆炸当量的估计量。对地下核爆炸产生的远震P尾波形成的了解可以提供包括爆炸点深度在内的有用的震源信息。     

Relationships between the global general circulation and the indian summer monsoon

The relationships between the global general circulation and the Indian monsoon during active and break phases are investigated with the help of FGGE IIIb data.It was found that the ultralong wave component positive and negative height anomalies over Tibet are associated with active and break monsoon phases respectively. This ultralong wave component has significant effect even upto 22oN over the Indian region which is the monsoon trough region. During a monsoon break, the general circulation was found to be more turbulent in the sense that more waves become energised.It was observed that during a break, blocking prevails over the Siberian region and cold air advection takes place toward Indian region from Siberian region depressing the temperatures over the Indian region by about 1oC. During the break, the Indian region gets connected with higher latitudes by the south winds blowing from polar Soviet re-gions to the Indian region. From active to break phase the zonal component weakens by about 25% from Indian ocean area right upto Alaskan region, along the east coast of Asia.     

用于大气成分资料时间序列分析的不对称滤波(摘译)

本文论述了利用大气成分月均值资料提取长期趋势和季节循环估计的不对称数字滤波设计。在保证估计信号的均方差增长相对小的前提下,可以减少记录末尾数据的遗失量。     

Gairloch地区Kerry Road含金矿体的地球物理研究

对苏格兰西北部Gairloch地区内超大型铜-锌-金硫化物矿体进行了包括磁法、电法和电磁法的综合地球物理探测。该层状矿床具有很好的导电性,以Loch Maree组为主,属刘易斯(Lewisian)期。虽然其它岩性也产生地球物理场异常,但这组岩性在物理性质上与硫化矿体形成了很好的对照。围绕矿体的很多钻孔提供了良好的地质控制。目的在于寻求不同地球物理方法检测到的各异常问的相关性以及估计这些异常对预测已知地质构造的价值几乎所有的方法都在出露矿化带上方显示出明显的异常,但发现有些方法对隐伏的或导电性差的矿化带的反应优于别的方法。对某一区域内被导电石墨层覆盖的隐伏矿化带,是通过对不同方法找出的异常进行比较后才发现的。典型的地球物理特性与很多岩性相关。这就有可能在隐伏露头区识别出不同的岩性。事实上有几种地球物理方法已经在没有发现过矿化带的地区找出了异常。     

太古宙大型矿床的分布——绿岩带随时间演化的线索之一

金矿化在太古宙绿岩带中的分布是不均匀的:大型(Au>50t)至特大型(Au>1000t)金矿床往往沿着一种特殊的、线型的绿岩地块的长轴方向成串分布,而其它类型的绿岩带却很少矿化。这种含有大型至特大型金矿床的绿岩带的例子是西澳大利亚耶尔岗地块中的Norseman—Wiluna绿岩带和加拿大地盾中的阿比提比绿岩带,两者的发     

Concentrations of Cd,Zn and Cu in sediments and brown shrimp (Crangon crangon L.) from the Severn Estuary and Bristol Channel,UK

Cd, Zn and Cu levels were determined in sediments and Crangon crangon from 9 sites in the Severn Estuary/Bristol Channel during winter 1999. Metal levels in both shrimp and sediments varied significantly between sites and were related to proximity of input and/or sediment type. In the upper Estuary, Cd levels in shrimp were 100x higher than other reported values whereas sediment Cd contamination was comparable. It is suggested that high Cd levels in shrimp are due to the high inputs and enhanced bioavailability of metal during winter.     

Cadmium detoxification processes in the digestive gland of cephalopods in relation to accumulated cadmium concentrations

The high concentrations of cadmium recorded in the digestive gland of cephalopods from various temperate and subpolar waters suggest that these molluscs have developed efficient cadmium detoxification mechanisms. The subcellular distribution of cadmium in the digestive gland cells was investigated in seven cephalopod species from the Bay of Biscay (France) and the Faroe Islands. In most species, cadmium was mainly found in the cytosolic fraction of the digestive gland cells, reaching up to 86% of the total cadmium for the squid Loligo vulgaris from the Bay of Biscay. But species with the highest total level of cadmium showed a higher percentage of cadmium associated to insoluble compounds. The quantification of metallothioneins (MTs) by the polarographic method was performed in order to evaluate the involvement of these proteins in the detoxification of the high amounts of bioaccumulated cadmium. Metallothionein levels in cephalopods ranged form 742 +/- 270 to 3478 +/- 1572 microg/g wet weight. No relationship could be established between total cadmium, cytosolic cadmium and MT levels suggesting the occurrence of other Cd-binding ligands. Although these proteins have not been characterised, as cadmium in the digestive gland of cephalopods is mainly associated with soluble ligands, a high potential transfer to predators can be predicted.