古代DNA 技术及其在家养动物驯化历史研究中的应用

家养动物始终伴随着人类文明的发生、发展, 其起源和驯化历史一直备受关注. 而在其 近万年的演化历史中, 家养和野生群体间可能发生基因互渗及替代, 因此基于现代物种DNA 信息进行的历史推断可能存在偏差. 近年来, 古代生物遗骸中的DNA (古代DNA)获取技术日 益成熟, 为这类研究开辟了新的途径. 本文总结了近年来古代DNA 技术研究进展, 点评了古 代生物遗骸DNA 的获取和鉴别方法、古代DNA 提取、扩增及测序技术的革新. 最后, 本文综 述了古代DNA 技术在猪、马、羊、狗等主要家养动物驯化历史研究中的应用进展, 为该技术 的进一步发展及应用提供有益的参考.     

信息环境下的高校图书馆与历史学研究

以计算机为代表的信息技术在图书馆的广泛应用,使图书馆呈现出文献资源共享、馆藏资源载体多样化及服务手段和服务方式灵活多样的发展趋势。图书馆的这种发展给历史学的学习和研究带来了良好契机,推动历史学朝着文献电子化、资源网络化、教学方式多样化及写作便捷化的方向发展。     

强震作用下双层球面网壳结构非线性动力响应分析

针对大跨网壳结构的动力特性,提出了在强烈地震作用下双层球面网壳结构的非线性分析和结构动力稳定性判别方法.单元模型中考虑几何非线性和材料非线性的双重影响.分析时,以静力荷载作用下的受力状态作为时程分析的初始状态,采用B-R判断准则确定其临界荷载,通过加速度峰值-结构最大位移曲线来判别结构的动力稳定性,据此找出其动力失稳临界点及破坏规律.通过算例验证了本文方法的有效性.分析结果表明,双层球面网壳结构考虑双重非线性是必要的;一致缺陷模态对结构承载力的影响比振型模态缺陷的影响大.     

Kant on anatomy and the status of the life sciences

This paper contributes to recent interest in Kant's engagement with the life sciences by focusing on one corner of those sciences that has received comparatively little attention: physical and comparative anatomy. By attending to remarks spread across Kant's writings, we gain some insight into Kant's understanding of the disciplinary limitations but also the methodological sophistication of the study of anatomy and physiology. Insofar as Kant highlights anatomy as a paradigmatic science guided by the principle of teleology in the Critique of the Power of Judgment, a more careful study of Kant's discussions of anatomy promises to illuminate some of the obscurities of that text and of his understanding of the life sciences more generally. In the end, it is argued, Kant's ambivalence with regard to anatomy gives way to a pessimistic conclusion about the possibility that anatomy, natural history, and, by extension, the life sciences more generally might one day become true natural sciences.     

From aether impulse to QED: Sommerfeld and the Bremsstrahlen theory

The radiation that is due to the braking of charged particles has been in the focus of theoretical physics since the discovery of X-rays by the end of the 19th century. The impact of cathode rays in the anti-cathode of an X-ray tube that resulted in the production of X-rays led to the view that X-rays are aether impulses spreading from the site of the impact. In 1909, Arnold Sommerfeld calculated from Maxwell׳s equations the angular distribution of electromagnetic radiation due to the braking of electrons. He thereby coined the notion of “Bremsstrahlen.” In 1923, Hendrik A. Kramers provided a quantum theoretical explanation of this process by means of Bohr׳s correspondence principle. With the advent of quantum mechanics the theory of bremsstrahlung became a target of opportunity for theorists like Yoshikatsu Sugiura, Robert Oppenheimer, and–again–Sommerfeld, who presented in 1931 a comprehensive treatise on this subject. Throughout the 1930s, Sommerfeld׳s disciples in Munich and elsewhere extended and improved the bremsstrahlen theory. Hans Bethe and Walter Heitler, in particular, in 1934 presented a theory that was later regarded as “the most important achievement of QED in the 1930s” (Freeman Dyson). From a historical perspective the bremsstrahlen problem may be regarded as a probe for the evolution of theories in response to revolutionary changes in the underlying principles.     

中药方剂中乳香类药物不良反应分析及临床对策

乳香可舒筋行气,活血化瘀,是中医治疗痹症、湿阻病等多种疾病的常用药材,但乳香类药物存在诱发不良反应的风险。通过回顾性研究,将2022年1—6月于北京中医药大学附属护国寺中医医院开具含有乳香成分的中药处方作为研究对象,通过统计描述、相关性分析及多因素回归分析,旨在明确影响乳香不良反应的独立性因素。采用的指标包括处方中的乳香剂量、给药方式,患者的年龄、性别、过敏史以及记录不良反应类型等。结果共纳入108例处方,其中7例处方引发了不良反应,包括皮肤过敏6例、腹泻1例,多因素回归分析显示患者既往过敏史是影响乳香不良反应的唯一独立危险因素;说明现阶段中医临床实践使用的含有乳香的中药方剂所致的不良反应仅与既往过敏史有关,患者过敏史是合理用药、控制不良反应中需重点把握的环节。     

南宁市城市森林发展现状与对策

介绍南宁市城市森林的发展及城市空间格局的变迁,指出南宁市城市森林发展中存在缺乏长期全面合理的规划、城市森林体系尚未形成,大量使用草坪、绿化模式单一,城市森林的经营管理水平较低、缺乏高层次的管理人才等问题.建议南宁市城市森林建设要与城市空间格局、环境格局相结合,完善城市森林体系建设;要因地制宜,突出地方城市森林特色;要将城市森林纳入生态网络,促进生物多样性和景观多样性;要保护城市生态环境,提高全民城市森林建设意识.     

基础隔震结构的能量反应分析

文章通过建立有隔震和无隔震的4层框架结构的分析模型,对其分别输入3条典型的地震波进行地震能量反应分析,结果表明隔震结构能较好地满足能量方程;适当降低隔震支座屈服强度对于保护上部结构更加有利;地震波的能量持时和卓越周期对结构地震能量反应具有重大影响。     

王安忆创作主题的多元呈现

王安忆的创作风格跟随时代的变化而发生变化,将王安忆作品与社会文化背景相结合,从"雯雯系列"、寻根文学、先锋文学、女性文学、城市文学五个主题的变化中,既体现出对潮流的追随,又执着地坚守着自己的本心.她的创作不仅是自我的突破,而且真实地反映了时代的变迁.     

The saws of sawflies: exploring the morphology of the ovipositor in Tenthredinoidea (Insecta: Hymenoptera), with emphasis on Nematinae

The variation in ovipositor sculpture and additional features of the ovipositor apparatus in Tenthredinoidea is explored. Two outgroups and 85 species of tenthredinoids were examined, the emphasis of the taxon sampling being on Nematinae. Twenty-four morphological characters where scored and the data set was analysed under different weighting conditions. The topologies derived from analysing the character set in TNT are poorly resolved and highly unstable when analytical settings are changed. Only a few clades, the Tenthredinoidea s. str., the Diprionidae, the Cimbicidae and the Argidae + Pergidae are consistently retrieved. The functional implications of the variation in ovipositor morphology within Tenthredinidae is discussed in relation to the qualities of the host plant, e.g. the hardness and the depth of penetration in plant tissue.