The record of cultivated rice from archaeobiological evidence in northwestern China 5000 years ago

Pollen, plant seeds and phytoliths from an AMS dated sediment profile at the Xishanping site indicate that the cultivation of rice might start no later than 5070 cal. a BP in the region of Tianshui, Gansu Province. It continued from 5070 to 4300 cal. a BP. This is so far the oldest and the most northwestern record of cultivated rice in Neolithic China, which extends the known region of prehistoric rice cultivation at least 2° longitude to the west. This finding provides important evidence for reconstructing the cultivation region of rice at 5000 a BP （an important time period）, and its spreading history in East Asia, during the Neolithic.     

航空机载软件适航性审定标准DO-178C与软件管理标准GJB5000A的比较分析

航空机载软件适航性审定是验证软件安全性是否满足飞行要求的重要手段,审定依据的标准DO-178C是航空企业软件设计所必须遵循的规范要求,但在软件管理领域,还存在着重要的能力成熟度集成模型标准GJB5000A。比较分析了DO-178C与GJB5000A的异同,得出机载软件适航性审定在对软件开发过程的管理方面存在不足,提出需要加强企业在项目监控、过程测量与分析和风险管理方面的要求,并按照DO-178C标准的形式要求,给出了参考的改进方案。     

Reconstruction of temperature series in China for the last 5000 years

A temperature series with a 100 year resolution for the last 5000 years in China has been reconstructed by using 31 long-term temperature proxy series selected from recent publications in the last 20 years. The proxy records include pollens, stalagmites, lake-sediments, peat, ice cores and historical documents. The result reveals that in the millennial scale temperature variation it was warm in 3050-250 BC and it was cold in 250 BC-1950 AD. In the above two periods there were many stages of sub-scale temperature fluctuations. The result also shows an obvious temperature discrepancy on the century to multi-century scale between the Eastern Monsoon Region, the Qinghai-Tibet Region and the Northwestern Region in 2850 BC, 2350 BC, 1350 BC, 950-350 BC, 50-250 AD, and 550 AD. A comparison between the reconstructed series of this paper and some North Hemisphere temperature series indicates that in the long-term scale change, the temperature change in China is in phrase with that of the Northern Hemisphere during the last 5000 years, while on the century to multi-century scale there are differences at the beginning and end times, which may imply that temperature change does not occur simultaneously in different regions.     

近五千年来长江中下游干流的演变

主要根据河漫滩相沉积的加积过程与厚度变化,埋藏古树层及埋藏古文化层的分析,发现近五千年来长江中下游干流洪水位上升了大约20m,并发展了曲流、洲滩、分流,以及支流河口成为自然堤后湖的变化.造成上述种种变化的主要原因是气候变化、海面运动、泥沙淤积、构造运动及人为活动的影响等,估计今后,所述种种变化还会继续发展下去.