Hybridization plays a significant role in biological evolution. However, it is not clear whether ecological contingency differentially influences likelihood of hybridization, particularly at ecological margins where p...Hybridization plays a significant role in biological evolution. However, it is not clear whether ecological contingency differentially influences likelihood of hybridization, particularly at ecological margins where parental species may exhibit reduced fitnesses. Moreover, it is unknown whether future ecosystem change will increase the prevalence of hybridization. Ficus heterostyla and F. squamosa are closely related species co-distributed from southern Thailand to southwest China where hybridization, yielding viable seeds, has been documented. As a robust test of ecological factors driving hybridization, we investigated spatial hybridization signatures based on nuclear microsatellites from extensive population sampling across a widespread contact range. Both species showed high population differentiation and strong patterns of isolation by distance. Admixture estimates exposed asymmetric interspecific gene flow.Signatures of hybridization increase significantly towards higher latitude zones, peaking at the northern climatic margins. Geographic variation in reproductive phenology combined with ecologically challenging marginal habitats may promote this phenomenon. Our work is a first systematic evaluation of such patterns in a comprehensive, latitudinally-based clinal context, and indicates that tendency to hybridize appears strongly influenced by environmental conditions. Moreover, that future climate change scenarios will likely alter and possibly augment cases of hybridization at ecosystem scales.展开更多
2024年5月23日,在国际测量师联合会(International Federation of Surveyors,FIG)第47届会员代表大会上,《北京测绘》编委、第十四届全国政协委员、中国测绘科学研究院院长、中国测绘学会副理事长燕琴研究员当选新一届FIG副主席,任期为2...2024年5月23日,在国际测量师联合会(International Federation of Surveyors,FIG)第47届会员代表大会上,《北京测绘》编委、第十四届全国政协委员、中国测绘科学研究院院长、中国测绘学会副理事长燕琴研究员当选新一届FIG副主席,任期为2025-2028年。FIG成立于1878年7月18日,是世界各国测绘学术团体联合组成的综合性学术组织,FIG的宗旨是联合世界各国及各地区的测量工作者、测绘工作团体、主管测绘的国家结构,讨论本专业共同关心的话题,建立各成员国测量学会间的联系,报道各国测量工作的成就,推广科研成果,组织专业培训,促进各国专业人员的交流,推动测量科学的发展。展开更多
The common fig（Ficus carica L.）was one of the earliest horticultural crops to be domesticated.A number of different viruses can infect fig trees including Fig mosaic virus（FMV）that has been detected in several com...The common fig（Ficus carica L.）was one of the earliest horticultural crops to be domesticated.A number of different viruses can infect fig trees including Fig mosaic virus（FMV）that has been detected in several commercial fig trees in Xinjiang,China.However,the distribution of FMV and other fig-infecting viruses in China remains unknown.In the present study,a sample from an ancient fig tree growing in Xinjiang was investigated by electron microscopy（EM）followed by PCR/RT-PCR,and FMV,Fig badnavirus 1（FBV-1）and Fig leaf mottle-associated virus 1（FLMaV-1）were detected.Fig leaf samples（252）from commercial orchards across China were subjected to PCR/RT-PCR,and FMV,FBV-1 and Fig fleck-associated virus（FFka V）were relatively abundant（44.4,48.4 and 44%,respectively）,while FLMaV-1 and Fig mild mottle-associated virus（FMMa V）were much scarcer（5.6 and 0.4%,respectively）,and FLMaV-2,Fig cryptic virus（FCV）,and Fig latent virus（FLV）were not detected.The presence of disease-causing viruses in fig trees presents a significant challenge for fig producers in China.This study may help to promote actions aimed at controlling fig viruses,especially FMV.展开更多
Crane’s most well-known work,The Red Badge of Courage,is commonly believed to be the first great novel of the American Civil War,largely because of its vivid and detailed description of the experience of warfare.This...Crane’s most well-known work,The Red Badge of Courage,is commonly believed to be the first great novel of the American Civil War,largely because of its vivid and detailed description of the experience of warfare.This paper conveys figure images symbolize that human life is insignificant in an indifferent universe in the novel,which are perfect symbolic images distinguish Crane as a forerunner of modernistic writers.展开更多
为了对某型号姿控发动机高空模拟试验推力现场校准斜率进行趋势预测,提出了一种模糊信息粒化(fuzzy information granulation,FIG)和支持向量回归机(support vector regression,SVR)相结合的时间序列预测方法。借助模糊信息粒化方法将...为了对某型号姿控发动机高空模拟试验推力现场校准斜率进行趋势预测,提出了一种模糊信息粒化(fuzzy information granulation,FIG)和支持向量回归机(support vector regression,SVR)相结合的时间序列预测方法。借助模糊信息粒化方法将推力现场校准的斜率映射为包含区间最小值Low、中值R和最大值Up 3个参数的模糊信息粒,以降低样本的维数,并以其为输入构建SVR回归模型。预测结果表明,基于模糊信息粒化SVR确定的预测区间较好地反映了推力现场校准斜率的变化趋势。展开更多
基金supported by the National Natural Science Foundation of China (3180031332261123001)+1 种基金Applied Basic Research Foundation of Yunnan Province (202301AT070378, 2019FB034)the “Light of West China” Program of the Chinese Academic of Sciences to J.-F.Huang。
文摘Hybridization plays a significant role in biological evolution. However, it is not clear whether ecological contingency differentially influences likelihood of hybridization, particularly at ecological margins where parental species may exhibit reduced fitnesses. Moreover, it is unknown whether future ecosystem change will increase the prevalence of hybridization. Ficus heterostyla and F. squamosa are closely related species co-distributed from southern Thailand to southwest China where hybridization, yielding viable seeds, has been documented. As a robust test of ecological factors driving hybridization, we investigated spatial hybridization signatures based on nuclear microsatellites from extensive population sampling across a widespread contact range. Both species showed high population differentiation and strong patterns of isolation by distance. Admixture estimates exposed asymmetric interspecific gene flow.Signatures of hybridization increase significantly towards higher latitude zones, peaking at the northern climatic margins. Geographic variation in reproductive phenology combined with ecologically challenging marginal habitats may promote this phenomenon. Our work is a first systematic evaluation of such patterns in a comprehensive, latitudinally-based clinal context, and indicates that tendency to hybridize appears strongly influenced by environmental conditions. Moreover, that future climate change scenarios will likely alter and possibly augment cases of hybridization at ecosystem scales.
文摘2024年5月23日,在国际测量师联合会(International Federation of Surveyors,FIG)第47届会员代表大会上,《北京测绘》编委、第十四届全国政协委员、中国测绘科学研究院院长、中国测绘学会副理事长燕琴研究员当选新一届FIG副主席,任期为2025-2028年。FIG成立于1878年7月18日,是世界各国测绘学术团体联合组成的综合性学术组织,FIG的宗旨是联合世界各国及各地区的测量工作者、测绘工作团体、主管测绘的国家结构,讨论本专业共同关心的话题,建立各成员国测量学会间的联系,报道各国测量工作的成就,推广科研成果,组织专业培训,促进各国专业人员的交流,推动测量科学的发展。
基金supported by grants from the Special Fund for Agro-scientific Research in the Public Interest, China (201203076)the Opening Fund of the State Key Laboratory for Biology of Plant Diseases and Insect Pests, China (SKLOF201518)
文摘The common fig（Ficus carica L.）was one of the earliest horticultural crops to be domesticated.A number of different viruses can infect fig trees including Fig mosaic virus（FMV）that has been detected in several commercial fig trees in Xinjiang,China.However,the distribution of FMV and other fig-infecting viruses in China remains unknown.In the present study,a sample from an ancient fig tree growing in Xinjiang was investigated by electron microscopy（EM）followed by PCR/RT-PCR,and FMV,Fig badnavirus 1（FBV-1）and Fig leaf mottle-associated virus 1（FLMaV-1）were detected.Fig leaf samples（252）from commercial orchards across China were subjected to PCR/RT-PCR,and FMV,FBV-1 and Fig fleck-associated virus（FFka V）were relatively abundant（44.4,48.4 and 44%,respectively）,while FLMaV-1 and Fig mild mottle-associated virus（FMMa V）were much scarcer（5.6 and 0.4%,respectively）,and FLMaV-2,Fig cryptic virus（FCV）,and Fig latent virus（FLV）were not detected.The presence of disease-causing viruses in fig trees presents a significant challenge for fig producers in China.This study may help to promote actions aimed at controlling fig viruses,especially FMV.
文摘Crane’s most well-known work,The Red Badge of Courage,is commonly believed to be the first great novel of the American Civil War,largely because of its vivid and detailed description of the experience of warfare.This paper conveys figure images symbolize that human life is insignificant in an indifferent universe in the novel,which are perfect symbolic images distinguish Crane as a forerunner of modernistic writers.
