Population genetics of Crassostrea ariakensis in Asia inferred from microsatellite markers

Crassostrea ariakensis is an important aquacultured oyster species in Asia, its native region. During the past decade, consideration was given to introducing C. ariakensis into Chesapeake Bay, in the United States, to help revive the declining native oyster industry and bolster the local ecosystem. Little is known about the ecology and biology of this species in Asia due to confusion with nomenclature and difficulty in accurately identifying the species of wild populations in their natural environment. Even less research has been done on the population genetics of native populations of C. ariakensis in Asia. We examined the magnitude and pattern of genetic differentiation among 10 wild populations of C. ariakensis from its confirmed distribution range using eight polymorphic microsatellite markers. Results showed a small but significant global theta (ST) (0.018), indicating genetic heterogeneity among populations. Eight genetically distinct populations were further distinguished based on population pairwise theta (ST) comparisons, including one in Japan, four in China, and three populations along the coast of South Korea. A significant positive association was detected between genetic and geographic distances among populations, suggesting a genetic pattern of isolation by distance. This research represents a novel observation on wild genetic population structuring in a coastal bivalve species along the coast of the northwest Pacific.

机器人多级自适应控制器的设计与数字仿真

本文提出了用多级自适应控制的方法实现机器人关节系统的自适应控制,并给出了两级自适应控制器的设计方法.最后以某机器人关节系统为对象对两级自适应控制器进行了仿真分析.

机器人语言研究

本文从信息控制的角度出发将机器人语言定义为能处理某些特定的“外部设备”的计算机程序设计语言。并将机器人语言成份分为两大部分,即机器人核心语言和机器人专用语言。然后分别综述了机器人专用语言和机器人核心语言的进展情况。

岩溶生态系统的土壤特性及其今后研究方向

岩溶石漠化退化土地是目前西南岩溶地区经济发展、生态恢复与重建工作中严重的问题之一。由于岩溶生态系统的独特性和脆弱性, 岩溶生态系统土壤具有不同于其它生态脆弱区土壤的特征, 本文将其归纳为成土速率决定的在人类活动尺度下土壤不可再生性即脆弱性、土壤侵蚀(土层丢失) 的独特性、土壤退化过程中空间分布的斑块化及其与岩性的相关性、土壤退化过程中有机碳活性成分下降和来源变化、土壤退化导致岩溶生态系统生态过程中断。因此, 在退化岩溶生态系统的研究中, 要加强对岩溶生态系统土壤特性及退化恢复理论的研究。

铜、锌同位素的化学前处理方法

过渡族金属同位素研究是近几年才发展起来的研究领域,在环境、生物、成矿和天体化学方面有着巨大的发展潜力.但过渡族金属的分离和同位素的测定方法并不十分成熟.本文就过渡金属同位素的测定方法做了简要概述并通过条件试验得出一些简单结论.