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371.
Cryptic diversity and phylogeography of the island‐associated barnacle Chthamalus moro in Asia
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Pleistocene glaciations were among the important historic events that shaped the population structures of marine organisms. Genetic studies of different marine fauna and flora have demonstrated the effect of Pleistocene glaciations on taxa that reside in marginal seas. However, how marine island species responded to Pleistocene glaciations remains relatively unstudied, especially in Asia. Genetic analyses based on the island‐associated barnacle Chthamalus moro collected from 14 sites in Asia reveal that C. moro comprises three distinct lineages, with COI divergence ranging from 3.9 to 8.3%. Population genetic analyses on respective lineages reveal signs of demographic expansion within the Pleistocene epoch at different times. The Ogasawara lineage, which has a more oceanic distribution, expanded the earliest, followed by the population expansion of the Ryukyu and Southern lineages that inhabit islands closer to the continent. The data suggest that the inhabitants of outer islands may have been less affected by Pleistocene glaciations than those that reside closer to the continent, as the former were able to maintain a large, stable, effective population size throughout the late Pleistocene. 相似文献
372.
Ka Man Chan Dan Dan Huang Yong Jie Li Man Nin Chan John H. Seinfeld Chak K. Chan 《Journal of Atmospheric Chemistry》2013,70(1):1-18
Methyl vinyl ketone (MVK) is a key first-generation product from atmospheric isoprene photo-oxidation, especially under high-NOx conditions. In this work, acid-catalyzed reactions of gas-phase MVK with ammonium sulfate (AS), ammonium bisulfate (ABS), and sulfuric acid (SA) particles were investigated in a flow reaction system at relative humidity (RH) of 40 % and 80 %. Ultra-performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry (UPLC/ESI-TOFMS) and gas chromatography-mass spectrometry (GC-MS) are utilized to identify particle-phase products for developing the reaction mechanisms. High-order oligomers such as dimers and tetramers were detected when ABS and SA particles were used, while no oligomeric products were found when AS particles were used. Particle-phase oligomeric products were formed via i) acid-catalyzed aldol reaction with or without dehydration and/or ii) acid-catalyzed hydration followed by oligomerization. Reactions on SA particles yield more abundant and higher-order oligomers up to hexamers than on ABS particles. Moreover, aldol reaction occurred only on SA particles, but hydration followed by oligomerization occurred in both ABS and SA particles. The high RH condition with the same type of acidic particles was found to favor hydration and facilitate the subsequent oligomerization, while the low RH condition with the same type of acidic particles was found to favor aldol reaction with dehydration (aldol condensation). Overall, the findings suggest acidic particles can facilitate the formation of high-order oligomers in the particle phase, with particle acidity and RH as key factors. 相似文献
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374.
车载三维数据采集系统的绝对标定及精度分析 总被引:1,自引:0,他引:1
针对GPS/INS/CCD相机集成的车载三维数据采集系统,给出了系统精确的直接定位方程,并将罗德里格矩阵用到系统的绝对标定中,推导了定位方程中所需的相机坐标系和惯导载体坐标系之间的平移与旋转参数的求解公式.然后,根据误差传播定律,推导了X、Y、Z三个方向上的坐标误差公式及点位误差公式.实验结果表明,本标定方法意义明确,计算过程简单,具有较高的标定精度,对实际应用具有重要的价值. 相似文献
375.