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

Chelazzi G  De Pirro M  Williams GA 《Marine environmental research》2004,58(1):83-93

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.  相似文献   

主动式声纳列阵拖曳系统姿态数值计算   总被引：2，自引：1，他引：2  

卢军 《海洋工程》2001,19(3):85-90

主动式声纳列阵拖曳系统是用于探测潜艇的新型声纳系统，为了准确探测潜艇的位置，必须首先预报声纳列阵的瓷态，本文通过对其三维力学模型的分析，得到该系统的运动微分方程，其中缆索的力学方程是基于Ablow和Milinazzo的模型，而对于拖体则运用六自由度空间运动方程模拟，结合边界条件，用有限差分法求解，通过对拖船的不同运动状态如匀速，变速和回转的计算，证明本文的方法对于预报声纳列阵的姿态是有效的。  相似文献   

Demographic transition in Sri Lanka: a spatial perspective   总被引：1，自引：0，他引：1  

Fuller GA 《Population geography : a journal of the Association of Population Geographers of India》1984,6(1-2):1-11

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.  相似文献   

当前我国地震预报面临的主要科学问题及其建议     

赵玉林  钱复业  卢军 《国际地震动态》2002,(12):1-4

论述了我国目前在长期、中期和短临预报中所面临的主要科学问题，提出了从哪些方面进行突破的建议。  相似文献   

3年独立研究观测到的地震有关的地电变化     

Tsel.  GA 卢军 《世界地震译丛》1997,(3):9-13

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。  相似文献   

高三复习冲刺阶段的教学策略     

卢军 《地理教学》2005,(5):30-32

一、近年地理高考试题趋向。1．强化地图载体，考查读图用图技能。地图是地理信息的载体，也是学生学习地理不可或缺的工具，因此，地理高考理应检测这一最重要的学习能力，重点考查学生学习地理的过程。从试题设计上来凸现过程性评价，正符合新课程标准理念。一般说来，学生平时对较简单的区域图、统计图、景观图掌握较好，但有几种难图需加强读练：  相似文献   

双壁钻具用的封隔器     

Ford.  GA 赵杰伟 《国外地质勘探技术》1990,(8):12-13,34

  相似文献   

城市地区灾害评价和沉积学模式的应用     

M‘Kr.  GA  王伍云 《国外第四纪地质》1989,(3):14-24

  相似文献   

井筒施工条件预测方法     

Ferg  GA 赵蔼廉 《国外煤田地质》1989,(5):37-41

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巴布亚新几内亚的波格拉金矿床     

Hand.  GA  林晓辉 《前寒武纪研究进展》1989,(1):53-60

  相似文献