Chromosomal location and evolutionary rate variation in enterobacterial genes

The basal rate of DNA sequence evolution in enterobacteria, as seen in the extent of divergence between Escherichia coli and Salmonella typhimurium, varies greatly among genes, even when only "silent" sites are considered. The degree of divergence is clearly related to the level of gene expression, reflecting constraints on synonymous codon choice. However, where this constraint is weak, among genes not expressed at high levels, divergence is also related to the chromosomal location of the gene; it appears that genes furthest away from oriC, the origin of replication, have a mutation rate approximately two times that of genes near oriC.     

In situ evolutionary rate measurements show ecological success of recently emerged bacterial hybrids

Few data are available on how quickly free-living microorganisms evolve. We analyzed biofilms collected from a well-defined acid mine drainage system over 9 years to investigate the processes and determine rates of bacterial evolution directly in the environment. Population metagenomic analyses of the dominant primary producer yielded the nucleotide substitution rate, which we used to show that proliferation of a series of recombinant bacterial strains occurred over the past few decades. The ecological success of hybrid bacterial types highlights the role of evolutionary processes in rapid adaptation within natural microbial communities.     

青岛蓝莓生态气候条件分析及气候品质论证

基于1970—2010年青岛地区7个国家级自动站气象资料及青岛市气象站、黄岛区气象站和张家楼镇气象站2018年气象资料,利用统计方法,分析青岛市黄岛区张家楼镇蓝莓的气候条件以及青岛地区的地理、环境、土壤条件等,并通过筛选蓝莓气候品质指标,建立气候品质等级评价体系,构建蓝莓气候品质论证模型。结果表明,蓝莓在青岛地区种植有较适宜的温度、日照时数,适宜蓝莓生长、发育,但3—6月降水量偏低,不利于蓝莓生长;黄岛区境内土壤较肥沃,呈中性或微酸性,适合蓝莓生长。按照评价体系指标的认证评分,得出青岛市黄岛区张家楼镇蓝莓得分为93.9分;根据气候品质评价指数(ACQI),认证青岛市黄岛区蓝莓气候品质等级为特优级。蓝莓气候品质认证实例分析,对探索农产品气候品质认证技术应用、合理利用气候资源以及为"三农"增产增收、打造青岛蓝莓农产品品牌、提升市场竞争力具有重要意义。     

关于气候变化问题及其研究的几点意见

通过对大量与气候变化有关的研究和相关的佐证资料整理及综合分析,提出了在气候变化及其研究问题上几个值得关注的问题,并根据农业上的气象灾害时间分布特点重点探讨了波动说理论,重点是让人们对气候变化问题引起关注并在研究中要注意做到客观、公正、严谨。     

Climate change. Climate in Medieval time

Many papers have referred to a "Medieval Warm Period." But how well defined is climate in this period, and was it as warm as or warmer than it is today? In their Perspective, Bradley et al. review the evidence and conclude that although the High Medieval (1100 to 1200 A.D.) was warmer than subsequent centuries, it was not warmer than the late 20th century. Moreover, the warmest Medieval temperatures were not synchronous around the globe. Large changes in precipitation patterns are a particular characteristic of "High Medieval" time. The underlying mechanisms for such changes must be elucidated further to inform the ongoing debate on natural climate variability and anthropogenic climate change.     

Post-cambrian trilobite diversity and evolutionary faunas

A cluster analysis of the stratigraphic distribution of all Ordovician trilobite families, based on a comprehensive taxonomic database, identified two major faunas with disjunct temporal diversity trends. The Ibex Fauna behaved as a cohort, declining through the Ordovician and disappearing at the end-Ordovician mass extinction. In contrast, the Whiterock Fauna radiated rapidly during the Middle Ordovician and gave rise to all post-Ordovician trilobite diversity. Its pattern of diversification matches that of the Paleozoic Evolutionary Fauna; hence, trilobites were active participants in the great Ordovician radiations. Extinction patterns at the end of the Ordovician are related to clade size: Surviving trilobite families show higher genus diversity than extinguished families.     

Climate change and violent conflict

Current debates over the relation between climate change and conflict originate in a lack of data, as well as the complexity of pathways connecting the two phenomena.     

全球气候变化与生物多样性

综述了全球气候变化与生我的我样性的研究现状，讨论了全球气候变化引起物种灭绝的内在机制，并从全球变暖与生物多样性丢失间的正反馈因果关系出发，指出保护全球生物多样性对遏制全球变暖的重要价值，同时也指出了生物多样性与全球气候变化研究的方向。