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本文应用文献的方法,以海城、唐山地震为例,探讨了缺震曲线对强震的反映.得出初步结果如下:(1)"缺震"方法作为一种指标对于强、中强震具有中期预报意义.(2)强震前缺震曲线的异常幅值较大且水平相当(海城、唐山震前异常幅值均为-1.4),震级越大缺震时间越长.(3)缺震曲线对中强地震也有较明显的反映,但同强震前相比异常幅值较小、异常时间较短. 相似文献
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利用数学方法对相关性定量分析，得出吉林省中部地区与黑龙江省萝北地区地震活动存在明显相关的结论。这种相关性对吉林省中短期地震预报具有实际意义。 相似文献
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Holmes AL Wise SS Goertz CE Dunn JL Gulland FM Gelatt T Beckmen KB Burek K Atkinson S Bozza M Taylor R Zheng T Zhang Y Aboueissa AM Wise JP 《Marine pollution bulletin》2008,56(8):1416-1421
The endangered Western population of the Steller sea lion declined for three decades for uncertain reasons. We present baseline data of metal concentrations in pups as a first step towards investigating the potential threat of developmental exposures to contaminants. Seven metals were investigated: arsenic, cadmium, silver, aluminum, mercury, lead and vanadium. Vanadium was detected in only a single blubber sample. Mercury appears to be the most toxicologically significant metal with concentrations in the liver well above the current action level for mercury in fish. The concentrations of aluminum, arsenic, silver, cadmium and lead were present in one-fourth to two-thirds of all samples and were at either comparable or below concentrations previously reported. Neither gender nor region had a significant effect on metal burdens. Future work should consider metal concentrations in juveniles and adults and toxicological studies need to be performed to begin to assess the toxicity of these metals. 相似文献
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The effects of salinity, temperature, and light conditions on the reproduction and development of harpacticoid copepod, Nitocra affinis f. californica under controlled laboratory conditions were determined. Seven different salinity levels (5, 10, 15, 20, 25, 30, 35 ppt), four temperatures (20, 25, 30, 35 °C), three different light intensities (25, 56, 130 μmol m−2 s−1) and photoperiods (24 h:0 h, 1 h:23 h, 12 h:12 h LD cycle) were employed in this study. The highest (p < 0.05) overall reproduction and fastest development time were achieved by copepods reared under 30–35 ppt salinity. The optimum temperature required for the maximum reproduction was 30 °C while under 30 °C and 35 °C the copepod development time was shortest (p < 0.05) compared to other temperature levels. The overall reproduction was highest (p < 0.05) and development rate of N. affinis was shortest (p < 0.05) under lowest light intensity (25 μmol m−2 s−1). Continuous light (24 h:0 h LD) inhibited the egg production while, continuous darkness (1 h:23 h LD) and 12 h:12 h LD significantly favoured the overall reproductive activity of the female. Photoperiods 1 h:23 h and 12 h:12 h LD yielded highest total (p < 0.05) offspring female−1 coupled with highest (p < 0.05) survival percentage. This study illustrated that although N. affinis can tolerate wide range of environmental conditions, prolonged exposure to subnormal environments affect its reproduction and development. This study showed that this species can be mass cultured for commercial purposes and has a potential to be used for toxicity studies due to its high reproductive performance fast development and a wide range of tolerance to environmental conditions. 相似文献
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全球俯冲带形态特征研究 总被引：3，自引：1，他引：3
利用CNSS编辑的深源地震目录，对全球深度500km以上的俯冲板块形态进行研究，给出了俯冲带的俯冲参数，以及菲律宾和班达弧俯冲带的三维形态。 相似文献