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Moore MJ Mitrofanov IV Valentini SS Volkov VV Kurbskiy AV Zhimbey EN Eglinton LB Stegeman JJ 《Marine pollution bulletin》2003,46(1):107-119
Roach, goby and sturgeon were examined for cytochrome P4501A (CYP1A) expression and histopathology, in relation to contaminant burdens in fish and sediment. Gradients of induction of CYP1A were observed. Roach from the Ural and Ily River Deltas and roach and goby from the two stations nearest the Caspian Sea oil fields displayed higher levels of CYP1A expression in several organs than was observed in fish from further offshore. Great sturgeon and Russian sturgeon showed higher levels of CYP1A expression than was seen in starred sturgeon and gobies in the Ural delta. No fish showed evidence of contaminant-related histopathologies in the organs examined, despite the elevated CYP1A levels. Low levels of polychlorinated biphenyls and elevated levels of inshore and riverine petroleum hydrocarbons from these habitats suggest that this ongoing hydrocarbon exposure, and that from natural sources and long-term oil exploration on the Northeastern Caspian shore, contributed to the CYP1A induction observed. 相似文献
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同井安装的ZKGD3000-NT型地下水数据监测系统水温仪和SZW-1型数字式温度计在永年北杜井250 m深度进行对比观测与井水温梯度测量,结果表明,温度梯度都随着深度的增加,井水温度逐渐升高,水温与深度呈正相关,没有明显的梯度异常井段。但两者温度动态差异较大,SZW-1温度计观测结果动态稳定性高,可以判定温度22.58℃是永年井250 m深度的井水温度,基本保持稳定上升趋势,上升速率稳定;而同孔同深度安装的ZKGD3000-NT水温仪测值波动性较大,变化速率也大,呈现下降趋势或下降速率增大。 相似文献
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计算云南下关井水位和水温资料的相关性,结果表明,水位和水温的趋势性变化总体具有好的相关性和同步性.但在某些时间段内两者的相关性会发生显著变化,且与下关及附近地区中强以上地震对应较好,可能是一种地震前兆异常.研究水位、水温相关性变化比单一分析水位或水温动态能够获得更多信息. 相似文献
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土地利用变化研究中的细胞自动机与灰色局势决策 总被引：12，自引：0，他引：12
把细胞自动机和灰色局势决策结合起来对土地利用变换机制进行模拟。实验证明,基于灰色局势决策规划的细胞自动机是对土地利用变换机制从宏观和微观角度进行模拟的有效方法。 相似文献
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层次分析法中权重算法的一种改进 总被引：4，自引：0，他引：4
本文在层次分析法的基础上通过对判断矩阵的自修正、自协调，求得一致性矩阵的特征向量，从而获取因素权重。减少了求矩阵特征值及其一致性检验过程，使层次分析法得到了大大简化，在一致性较好的情况下，该方法能与Ｓａｔｔｙ迭代精确值得到一致的结果，最后给出了应用实例。 相似文献
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考虑到自然因素、社会因素对农作物单产影响的后效性,通过灰色系统建模,并应用马尔可夫链的状态转移概率矩阵,对农作物单产进行预测,其预测结果合理,产量年景基本正确。 相似文献
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In the tails of dromaeosaurid dinosaurs and rhamphorhynchid pterosaurs, elongate osteological rods extend anteriorly from the chevrons and the prezygapophyses. These caudal rods are positioned in parallel and are stacked dorsoventrally. The fully articulated and three-dimensionally preserved caudal series of some dromaeosaurid specimens show that individually these caudal rods were flexible, not rigid as previously thought. However, examination of the arrangement of the caudal rods in cross-section indicates that the combined effect of multiple caudal rods did provide substantial rigidity in the dorsoventral, but not in the lateral, plane. The results of digital muscle reconstructions confirm that dromaeosaurids and rhamphorhynchids also shared greatly reduced caudofemoral muscles in the anterior tail region. The striking similarities between the tails of dromaeosaurids and rhamphorhynchids suggest that both evolved under similar behavioral and biomechanical pressures. Combined with recent discoveries of primitive deinonychosaurs that phylogenetically bracket the evolution of dromaeosaurid caudal rods between two arboreal gliding/flying forms, these results are evidence that the unique caudal morphologies of dromaeosaurids and rhamphorhynchids were both adaptations for an aerial lifestyle. 相似文献
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分析丽江地震台数字化水平摆倾斜仪在几次中强震前记录的前兆波,对其特征进行初步分析,并对其产生机理进行初步探讨。认为数字化水平摆倾斜仪的独特构造和观测点的位置,构成了丽江地震台能观测到中强地震前兆波的原因。提高对前兆波的认识,对未来的地震预测有着实际应用价值。 相似文献