The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture.However,the timing and routes of cereal expansion in key regions are unclear...The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture.However,the timing and routes of cereal expansion in key regions are unclear due to limited empirical evidence.Here we report macrofossil,microfossil,multiple isotopic(C/N/Sr/O)and paleoproteomic data directly from radiocarbon-dated human samples,which were unearthed from a site in Xingyi in central Yunnan and which date between 7000 and 3300 a BP.Dietary isotopes reveal the earliest arrival of millet ca.4900 a BP,and greater reliance on plant and animal agriculture was indicated between 3800 and 3300 a BP.The dietary differences between hunter-gatherer and agricultural groups are also evident in the metabolic and immune system proteins analysed from their skeletal remains.The results of paleoproteomic analysis indicate that humans had divergent biological adaptations,with and without farming.The combined application of isotopes,archaeobotanical data and proteomics provides a new approach to documenting dietary and health changes across major subsistence transitions.展开更多
随着社会经济的发展和城镇化进程的加速,生态环境日益恶化,人类逐渐认识到不断出现的环境问题带来的严重后果,生态修复作为改善生态环境、保障人类福祉的重要手段,其科学研究和实践探索迅速发展。针对当前我国国土综合整治和生态修复的...随着社会经济的发展和城镇化进程的加速,生态环境日益恶化,人类逐渐认识到不断出现的环境问题带来的严重后果,生态修复作为改善生态环境、保障人类福祉的重要手段,其科学研究和实践探索迅速发展。针对当前我国国土综合整治和生态修复的理念和方法侧重于非生物环境和小范围特定环境的局限,在明确国际生态修复基本概念和内涵的基础上,基于CiteSpace对1988—2020年Web of Science期刊引文数据库中的4220篇生态修复文献,分析发文数量、关键词、前沿热点等,梳理和总结国际生态修复理念演变、不同目标和尺度下的修复方法与措施,提出我国新时期国土综合整治理念应建立可持续发展的社会—生态耦合系统,整治方法应加强生物多样性和生态系统保护、关注景观修复,整治管理应建立社会参与、绩效监督、多元化投入机制,以及整治实施应因地制宜,循序渐进。展开更多
The electron impact excitation(EIE) cross sections of an atom/ion in the whole energy region are needed in many research fields, such as astrophysics studies, inertial confinement fusion researches and so on. In the p...The electron impact excitation(EIE) cross sections of an atom/ion in the whole energy region are needed in many research fields, such as astrophysics studies, inertial confinement fusion researches and so on. In the present work, an effective method to calculate the EIE cross sections of an atom/ion in the whole energy region is presented. We use the EIE cross sections of helium as an illustration example. The optical forbidden 1^(1)S–n^(1)S(n = 2–4) and optical allowed 1^(1)S–n^(1)P(n = 2–4) excitation cross sections are calculated in the whole energy region using the scheme that combines the partial wave R-matrix method and the first Born approximation. The calculated cross sections are in good agreement with the available experimental measurements. Based on these accurate cross sections of our calculation, we find that the ratios between the accurate cross sections and Born cross sections are nearly the same for different excitation final states in the same channel. According to this interesting property, a universal correction function is proposed and given to calculate the accurate EIE cross sections with the same computational efforts of the widely used Born cross sections,which should be very useful in the related application fields. The datasets presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00142.展开更多
本文通过对含有平面四配位氮团簇NLi_(3)E^(+)(E=N,P,As)和它们的平面四配位碳等电子体CLi_(3)E(E=N,P,As)进行详细地对比,研究了电子定域策略在设计含平面四配位氮团簇时的适应性.结果表明,NLi_(3)E^(+)团簇具有类似于CLi_(3)E的平面结...本文通过对含有平面四配位氮团簇NLi_(3)E^(+)(E=N,P,As)和它们的平面四配位碳等电子体CLi_(3)E(E=N,P,As)进行详细地对比,研究了电子定域策略在设计含平面四配位氮团簇时的适应性.结果表明,NLi_(3)E^(+)团簇具有类似于CLi_(3)E的平面结构,且其平面性都是由一个定域的π键决定的.然而,与CLi_(3)E相比,NLi_(3)E^(+)明显具有更高的电子结构稳定性、热力学稳定性和动力学稳定性,这可以从更宽的HOMO-LUMO能隙(4.58~4.68 eV vs.2.10~2.74 eV)在CCSD(T)/aug-cc-pVTZ水平下较低的能量和DFT水平下的分子动力学模拟中表现出的更好刚性得到验证.结果表明,电子定域策略可能更适合设计中心原子为较高电负性且更倾向于形成定域键的平面多配位分子.在这些团簇中,NLi_(3)E^(+)的稳定性最好,更适合进行气相合成及后续的质谱选择和光谱表征.展开更多
基金the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0601)the Priority Research Program of the Chinese Academy of Sciences(XDA2004010101)+6 种基金the National Natural Science Foundation of China(42271160,32060208,31801040,and 32270667)the Major Project of National Social Science Foundation of China(21&ZD285and 20&ZD248)the National Key Research&Development Program of China(2020YFE0202200)Westlake Education FoundationNanqiang Outstanding Young Talents Program of Xiamen University(X2123302)the European Research Council Grant(ERC-2019-ADG-883700-TRAM)the Academician and Expert Workstation of Yunnan Province(202305AF150183)。
文摘The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture.However,the timing and routes of cereal expansion in key regions are unclear due to limited empirical evidence.Here we report macrofossil,microfossil,multiple isotopic(C/N/Sr/O)and paleoproteomic data directly from radiocarbon-dated human samples,which were unearthed from a site in Xingyi in central Yunnan and which date between 7000 and 3300 a BP.Dietary isotopes reveal the earliest arrival of millet ca.4900 a BP,and greater reliance on plant and animal agriculture was indicated between 3800 and 3300 a BP.The dietary differences between hunter-gatherer and agricultural groups are also evident in the metabolic and immune system proteins analysed from their skeletal remains.The results of paleoproteomic analysis indicate that humans had divergent biological adaptations,with and without farming.The combined application of isotopes,archaeobotanical data and proteomics provides a new approach to documenting dietary and health changes across major subsistence transitions.
文摘随着社会经济的发展和城镇化进程的加速,生态环境日益恶化,人类逐渐认识到不断出现的环境问题带来的严重后果,生态修复作为改善生态环境、保障人类福祉的重要手段,其科学研究和实践探索迅速发展。针对当前我国国土综合整治和生态修复的理念和方法侧重于非生物环境和小范围特定环境的局限,在明确国际生态修复基本概念和内涵的基础上,基于CiteSpace对1988—2020年Web of Science期刊引文数据库中的4220篇生态修复文献,分析发文数量、关键词、前沿热点等,梳理和总结国际生态修复理念演变、不同目标和尺度下的修复方法与措施,提出我国新时期国土综合整治理念应建立可持续发展的社会—生态耦合系统,整治方法应加强生物多样性和生态系统保护、关注景观修复,整治管理应建立社会参与、绩效监督、多元化投入机制,以及整治实施应因地制宜,循序渐进。
基金Project supported by the National Natural Science Foundation of China (Grant No. 12241410)。
文摘The electron impact excitation(EIE) cross sections of an atom/ion in the whole energy region are needed in many research fields, such as astrophysics studies, inertial confinement fusion researches and so on. In the present work, an effective method to calculate the EIE cross sections of an atom/ion in the whole energy region is presented. We use the EIE cross sections of helium as an illustration example. The optical forbidden 1^(1)S–n^(1)S(n = 2–4) and optical allowed 1^(1)S–n^(1)P(n = 2–4) excitation cross sections are calculated in the whole energy region using the scheme that combines the partial wave R-matrix method and the first Born approximation. The calculated cross sections are in good agreement with the available experimental measurements. Based on these accurate cross sections of our calculation, we find that the ratios between the accurate cross sections and Born cross sections are nearly the same for different excitation final states in the same channel. According to this interesting property, a universal correction function is proposed and given to calculate the accurate EIE cross sections with the same computational efforts of the widely used Born cross sections,which should be very useful in the related application fields. The datasets presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00142.
基金supported by the USTC Research Funds of the Double First-Class Initiative(YD2090002008)the Fundamental Research Funds for the Central Universities(WK2090000032).
基金This study was funded by the National Natural Science Foundation of China(Grant number 72074164)the Chinese Academy of Medical Sciences(Grant number 2020-JKCS-024)the Humanity and Social Science Youth Foundation of the Ministry of Education of China(Grant number 20YJCZH088).
基金supported by the National Natural Foudation of China(No.21720102006 and No.22073058)the High Performance Computer Center of Shanxi University.
文摘本文通过对含有平面四配位氮团簇NLi_(3)E^(+)(E=N,P,As)和它们的平面四配位碳等电子体CLi_(3)E(E=N,P,As)进行详细地对比,研究了电子定域策略在设计含平面四配位氮团簇时的适应性.结果表明,NLi_(3)E^(+)团簇具有类似于CLi_(3)E的平面结构,且其平面性都是由一个定域的π键决定的.然而,与CLi_(3)E相比,NLi_(3)E^(+)明显具有更高的电子结构稳定性、热力学稳定性和动力学稳定性,这可以从更宽的HOMO-LUMO能隙(4.58~4.68 eV vs.2.10~2.74 eV)在CCSD(T)/aug-cc-pVTZ水平下较低的能量和DFT水平下的分子动力学模拟中表现出的更好刚性得到验证.结果表明,电子定域策略可能更适合设计中心原子为较高电负性且更倾向于形成定域键的平面多配位分子.在这些团簇中,NLi_(3)E^(+)的稳定性最好,更适合进行气相合成及后续的质谱选择和光谱表征.
