Different cardiac response to copper in limpets from metal polluted and clean shores of Hong Kong

The gastropod limpet, Cellana grata, is common on moderately exposed to exposed Hong Kong rocky shores. On the basis of the existing literature on trace metal contamination in Hong Kong, four sites were identified, representative of highly polluted (Aberdeen and Lei Yue Mun) and clean (Cape d'Aguilar and Clear Water Bay) conditions. Limpets from the two polluted sites showed similar, but significantly higher body concentrations of copper than limpets from the two clean sites, which were also similar. Non-invasive measurements of cardiac activity of limpets from the four sites showed between site differences in baseline heart rates under standard seawater, irrespective of pollution level. When acutely exposed to water borne copper (2 h, 0.5+/-0.06 SD ppm), however, limpets from clean sites showed a significantly higher increase in inter-beating time (bradycardia) than those from polluted sites. These results highlight the potential use of cardiac activity to assess the exposure of natural populations of limpets to trace metal pollution.     

Demographic transition in Sri Lanka: a spatial perspective

Demographic transition theory involves a lagging fertility transition induced by a leading mortality transition. This article focuses on the linkage between the mortality and fertility transitions in Sri Lanka; it discusses the measurement of areal fertility, demonstrates the use of a measure not commonly used in population geography, and shows areal association between past mortality and recent fertility. The Coale or Princeton fertility indices allow a reasonably good view of structural and behavioral aspects of fertility; the Coale indices examine the contribution of structure to total fertility and the contribution of marital fertility. Although recent fertility decline has been less rapid than the post-war mortality decline, Sri Lanka's crude birth rate in 1975 was the 5th lowest in Asia. Sri Lanka experienced very high crude death rates in 1930, and quite low rates in 1950 and in subsequent years. This demonstrates an association between historic mortality and recent fertility, and that association can be linked deductively to demographic transition theory. In 1930, malaria was endemic throughout the Dry Zone of Sri Lanka, and hyperendemic in several districts. The Spearman rank correlation coefficients reveal the strongest relationship between malaria and nuptiality; this lends evidence to the notion that structural influences on fertility--such as delayed marriage--are more important than influences on marital fertility--such as coital frequency. The evidence suggests that mortalily decline in Sri Lanka led to an increase in fertility in those areas where malaria had been concentrated. This suggests the possibility that measures constituting malaria control or eradication also stimulate increased fertility; therefore, anti-malarial programs must be integrated with family planning.     

3年独立研究观测到的地震有关的地电变化

给出了某些地震前地电的观测结果。数据是在帕特雷大学地震中心用ＶＡＮ方法在３年独立实验研究期间搜集的。记录的信号包括：（ａ）地电场的缓慢变化；（ｂ）地电场的周期变化；（ｃ）地震电信号。     

加拿大安大略赫姆洛帕格-威廉斯金矿的地层、断裂和金矿的关系

导论金矿出现在加拿大地盾的许多绿岩带中,具有多种地质环境并可被划分成许多矿床类型,包括最近在赫姆洛发现的类型。研究者对金矿的生成是受地层和构造控制已开展争论。赫姆洛的威廉斯矿区的帕格-威廉斯金矿包括A、B、C三带。三个地貌上各异的金矿,均赋存在独特的断层控制的地层层序中,其规模、岩石、构造、丰度、含金的     

加拿大安大略州阿比提比绿岩带地质发展中金矿层形成的位置

安大略阿比提比(Abitibi)绿岩带火山岩的均匀(除花岗质岩石附近外)低级变质作用和巨大地层视厚度(～40公里),被解释是铲状正断裂的结果。紧接着断裂之后发生从拉斑质到钙碱质最后到钙碱性科马提质的火山旋回。地壳的断裂发生在花岗质岩石侵位的初期,在张应力作用下形成。这类花岗质岩基与钙碱性火山岩同源。在火山喷     

西澳大利亚地盾太古宙金矿床的成因和构造控制——变质交代模式

金矿床广泛出露在世界各地的绿岩带中,而太古宇岩区是主要产金岩区。象其他克拉通一样,西澳大利亚太古宙金矿化具代表矿床类型的复杂组合。尽管如此,大部分矿床明显是后生成因的,大型矿床具许多共同的特征,包括强烈控制,明显的围岩蚀变(硫化铁、钾云母±钠长石,Ca-Mg-Fe型碳酸盐),稳定的金属组合(Au-Ag-As-