河南栾川孙家洞遗址出土的穿孔标本

孙家洞遗址初步测年为40万年左右,出土了少量石制品、古人类牙齿以及大量动物化石,其中一件骨骼标本存在非常规整的穿孔,其整体形态和大小与人工穿孔比较相似。通过系统的宏观观测与显微镜下分析,并与已明确性质的考古标本(自然穿孔和人工穿孔标本)和实证材料(现代鬣狗洞发掘出土材料)进行对比后发现,孙家洞遗址出土的穿孔标本与食肉类啃咬、甲虫类啮食以及人工造成的穿孔标本存在明显差异,而具备了被鬣狗胃酸腐蚀标本的所有典型特征。     

丁村54：90地点石制品研究

此次研究的丁村５４：９０地点的石制品计１７１件,以大、中型为主,尤其是石器,大型者占石器总数的８３．３３％,在有刃类石器中,复刃多于单刃是其另一特点．５４：９０地点与５４：１００地点距离很近,高程相仿．两者的石制品差异显著,是有待探讨的问题．     

A simulation study on the accuracy of position and effect estimates of linked QTL and their asymptotic standard deviations using multiple interval mapping in an F2 scheme

Approaches like multiple interval mapping using a multiple-QTL model for simultaneously mapping QTL can aid the identification of multiple QTL, improve the precision of estimating QTL positions and effects, and are able to identify patterns and individual elements of QTL epistasis. Because of the statistical problems in analytically deriving the standard errors and the distributional form of the estimates and because the use of resampling techniques is not feasible for several linked QTL, there is the need to perform large-scale simulation studies in order to evaluate the accuracy of multiple interval mapping for linked QTL and to assess confidence intervals based on the standard statistical theory. From our simulation study it can be concluded that in comparison with a monogenetic background a reliable and accurate estimation of QTL positions and QTL effects of multiple QTL in a linkage group requires much more information from the data. The reduction of the marker interval size from 10 cM to 5 cM led to a higher power in QTL detection and to a remarkable improvement of the QTL position as well as the QTL effect estimates. This is different from the findings for (single) interval mapping. The empirical standard deviations of the genetic effect estimates were generally large and they were the largest for the epistatic effects. These of the dominance effects were larger than those of the additive effects. The asymptotic standard deviation of the position estimates was not a good criterion for the accuracy of the position estimates and confidence intervals based on the standard statistical theory had a clearly smaller empirical coverage probability as compared to the nominal probability. Furthermore the asymptotic standard deviation of the additive, dominance and epistatic effects did not reflect the empirical standard deviations of the estimates very well, when the relative QTL variance was smaller/equal to 0.5. The implications of the above findings are discussed.     

基于生态网络的山水林田湖草生物多样性保护研究——以广西左右江为例

“山水林田湖草是生命共同体”的理念强调生态系统的整体性,反映了自然界各生态系统之间的联系,表明对生态环境的治理要建立在系统论的思想方法上,怎样将“山水林田湖草”的理论思想落实到具体的地区已成为生态保护与修复的关注热点。生态网络的构建不仅可以连接破碎生境,而且能够综合考虑生态系统的各个要素,因此,以广西左右江流域为例,选取保护区作为生态源地,结合最小累积阻力模型（MCR,minimum cumulative resistance）和整体连通性指数（IIC,integral index of connectivity）,分析潜在生态廊道的结构组成以及源地重要性,探讨研究区潜在生态网络“山水林田湖草”空间分布。研究结果表明：通过构建生态网络识别出69条潜在生态廊道,但在研究区中部没有可利用的廊道,导致明显的南北阻隔;在51个源地斑块中,仅有3个斑块的重要性指数大于0.2,景观整体连通性较低;通过廊道景观构成的分析发现,耕地占廊道面积比例达20.28%,仅次于自然林地（74.16%）,说明耕地对生态网络的构建有重要影响。最后通过廊道与道路的叠加选取9个关键生态节点和23个断裂点,并提出相应的修复和优化对策。研究结果可为广西左右江流域生物多样性保护提供方法和建议,同时作为对“山水林田湖草”生态保护与修复的探索,能够为今后类似研究提供参考。