古土壤形成于过去环境,是揭示环境变化历史的重要材料。新近纪(23.03 M a)以前形成的古土壤,年代久远、埋藏深、受成岩作用改造强烈,其发生学特征研究是古环境重建的基础。本文通过对白垩纪时期不同地点的钙质古土壤的发生学研究,拟恢...古土壤形成于过去环境,是揭示环境变化历史的重要材料。新近纪(23.03 M a)以前形成的古土壤,年代久远、埋藏深、受成岩作用改造强烈,其发生学特征研究是古环境重建的基础。本文通过对白垩纪时期不同地点的钙质古土壤的发生学研究,拟恢复研究区域古环境。研究表明,古土壤剖面中的A层和B层形态分别产生变化,但层次差异依然明显,且表层土壤有机质含量一般高于表下层,钙积层(Bk)普遍发生并富含碳酸盐结核。可以观察到古土壤中方解石沿根孔淀积特征以及具滑擦面。钙质古土壤质地偏粗,为壤质砂土和砂质壤土。古土壤Bk层中的Ca、Mn、Sr相对富集,其余常量元素与Ba、Sc、Nb、Th、U、Cr、V、Co、N i等元素降低;δCe和δEu负异常以及相对富集重稀土元素。分别按照中国土壤分类系统和美国土壤系统分类两种分类体系进行了古土壤分类。由古土壤类型和特征可以推断白垩纪不同时期,在四川盆地梓潼—巴中地区、辽宁金岭寺—羊山盆地和松辽盆地出现过半湿润至半干旱的气候环境。展开更多
The four palaemonoid(sub)families Anchistioididae,Gnathophyllidae,Hymenoceridae,and Pontoniinae are similar in morphology,and all live in marine habitats.Their systematic relationships are controversial.In this study,...The four palaemonoid(sub)families Anchistioididae,Gnathophyllidae,Hymenoceridae,and Pontoniinae are similar in morphology,and all live in marine habitats.Their systematic relationships are controversial.In this study,we used sequences from a mitochondrial ribosomal gene(16S rRNA) and three nuclear genes(H3,NaK,and enolase) to explore the phylogenetic relationships of these four taxa.Our tree based on 43 species belonging to 28 genera shows that Gnathophyllidae and Hymenoceridae are nested within Pontoniinae.This result is consistent with evidence from larval morphology.The defining characteristics of Gnathophyllidae and Hymenoceridae,a vestigial or missing mandibular incisor process and a broadened third maxilliped,can also be found in Pontoniinae;conversely,on the basis of published species descriptions,gnathophyllids and hymenocerids meet most of the defining characteristics of Pontoniinae.The peculiar form of the third maxilliped in gnathophyllids and hymenocerids might be the result of adaptive evolution,as these particular features are also present in pontoniines.According to our phylogenetic tree,Anchistioididae are more remote from Pontoniinae,which is consistent with the distinct morphological differences in the pleopods.The pontoniine genera analyzed(together with Gnathophyllidae and Hymenoceridae) are divided into two clades.The members of Clade I exhibit primordial characteristics similar to those of the Palaemoninae,and might be direct descendants of the ancestor of the Pontoniinae;members of Clade II are more specialized.展开更多
On August 8, 2017, a Ms 7.0 earthquake occurred 5 km to the west of Jiuzhaigou National Park, causing 25 deaths and injuring 525. The objective of this study was to explore the seismogenic fault of the earthquake and ...On August 8, 2017, a Ms 7.0 earthquake occurred 5 km to the west of Jiuzhaigou National Park, causing 25 deaths and injuring 525. The objective of this study was to explore the seismogenic fault of the earthquake and tectonic dynamics of the source rupture. Field investigations, radon activity tests, remote sensing interpretations, and geophysical data analyses were carried out immediately after the earthquake. The Jiuzhaigou earthquake occurred at the intersection of the northern margin of the Minshan uplift belt and the south part of the Wenxian–Maqin fault in the south margin of the West Qinling geosyncline. There are two surface rupture zones trending northwest(NW), which are ground coseismic ruptures caused by concealed earthquake faults. The rupture on the southwest is the structure triggering the earthquake, along the Jiuzhaitiantang–Epicenter–Wuhuahai. The other one on the northeast(Shangsizhai–Zhongcha–Bimang) is a reactivation and extension of the secondary fault trending NW. The source rupture of this earthquake is a strike-slipshear fracture associated with the fault plane trending NW 331° and steeply dipping 75°, which is continuously expanding at both ends. The tectonic dynamics process of the source rupture is that the "Jiuzhaigou protrusion" is left-lateral sheared along the seismogenic fault in the NW direction. Finally, the Maqin fault and the arc fault system at the top of the "Wenxian protrusion" will be gradually broken through sometime in far future, as well as earthquaketriggered landslides will be further occurred along the narrow corridor between the seismogenic faults. The research results revealed the basic geological data and tectonic dynamic mechanism in this earthquake.展开更多
Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine ...Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine traffic accident mortality trends and their epidemiologic characteristics in the Kermanshah province, west of lran. Methods： In a cross sectional study, road traffic fatality data from 2004 to 2013 were analyzed to determine the epidemiological pattern of traffic accident mortality. Trend assessment was performed to ascertain the decreasing or increasing status. Chi-square and one-way analysis of variance （ANOVA） tests, as well as Poisson regression were used to determine the significance of the data in time. Data were analyzed using Excel and statistical package of SPSS version 19. Results： Out of 5110 people that died in traffic accidents, 4024 （78.7%） were males. The state of accidents indicated that 404 （43.8%） female pedestrians died as a result of car crashes, and 1330 （41.4%） males died because of car collisions. 1554 （31.9%） deaths happened to pedestrians and 1556 （32.1%） to vehicle drivers, and the rest belonged to vehicle passengers. Head trauma was the cause of death for as much as 3400 （69.9%） cases. Fatal crashes in which pedestrians were involved mostly occurred between the hours 13：00 to 15：00, while the time for vehicle drivers was between 16：00 to 18：00. 2882 people （59.1%） died before reaching to health care facilities. Traffic crash mortality trend for pedestrians follows a linear pattern with a gentle downward slope, but the trend shows various swings when it comes to vehicle drivers. Conclusion： The number of traffic crash deaths from 2004 to 2013 indicates a decreasing trend in two groups of road users： vehicle drivers and car occupants. This can be due to some interventions such as modification of traffic rules and enhancement of police control which has been implemented in recent years. Moreover, more attention should be paid to promote the optimal health care services to save the lives of the injured from traffic accidents.展开更多
文摘古土壤形成于过去环境,是揭示环境变化历史的重要材料。新近纪(23.03 M a)以前形成的古土壤,年代久远、埋藏深、受成岩作用改造强烈,其发生学特征研究是古环境重建的基础。本文通过对白垩纪时期不同地点的钙质古土壤的发生学研究,拟恢复研究区域古环境。研究表明,古土壤剖面中的A层和B层形态分别产生变化,但层次差异依然明显,且表层土壤有机质含量一般高于表下层,钙积层(Bk)普遍发生并富含碳酸盐结核。可以观察到古土壤中方解石沿根孔淀积特征以及具滑擦面。钙质古土壤质地偏粗,为壤质砂土和砂质壤土。古土壤Bk层中的Ca、Mn、Sr相对富集,其余常量元素与Ba、Sc、Nb、Th、U、Cr、V、Co、N i等元素降低;δCe和δEu负异常以及相对富集重稀土元素。分别按照中国土壤分类系统和美国土壤系统分类两种分类体系进行了古土壤分类。由古土壤类型和特征可以推断白垩纪不同时期,在四川盆地梓潼—巴中地区、辽宁金岭寺—羊山盆地和松辽盆地出现过半湿润至半干旱的气候环境。
基金Supported by the National Natural Science Foundation of China(Nos.41376163,30499340)the National Science Council,Taiwan to CHAN Tinyam
文摘The four palaemonoid(sub)families Anchistioididae,Gnathophyllidae,Hymenoceridae,and Pontoniinae are similar in morphology,and all live in marine habitats.Their systematic relationships are controversial.In this study,we used sequences from a mitochondrial ribosomal gene(16S rRNA) and three nuclear genes(H3,NaK,and enolase) to explore the phylogenetic relationships of these four taxa.Our tree based on 43 species belonging to 28 genera shows that Gnathophyllidae and Hymenoceridae are nested within Pontoniinae.This result is consistent with evidence from larval morphology.The defining characteristics of Gnathophyllidae and Hymenoceridae,a vestigial or missing mandibular incisor process and a broadened third maxilliped,can also be found in Pontoniinae;conversely,on the basis of published species descriptions,gnathophyllids and hymenocerids meet most of the defining characteristics of Pontoniinae.The peculiar form of the third maxilliped in gnathophyllids and hymenocerids might be the result of adaptive evolution,as these particular features are also present in pontoniines.According to our phylogenetic tree,Anchistioididae are more remote from Pontoniinae,which is consistent with the distinct morphological differences in the pleopods.The pontoniine genera analyzed(together with Gnathophyllidae and Hymenoceridae) are divided into two clades.The members of Clade I exhibit primordial characteristics similar to those of the Palaemoninae,and might be direct descendants of the ancestor of the Pontoniinae;members of Clade II are more specialized.
基金financially supported by the Open Research Fund from the Key Laboratory of Mountain Hazards and Earth Surface Process(Chinese Academy of Sciences)(Grant No.KLMHESP-17-06)the Independent Research Fund from the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology)(Grant No.40100-00002219)
文摘On August 8, 2017, a Ms 7.0 earthquake occurred 5 km to the west of Jiuzhaigou National Park, causing 25 deaths and injuring 525. The objective of this study was to explore the seismogenic fault of the earthquake and tectonic dynamics of the source rupture. Field investigations, radon activity tests, remote sensing interpretations, and geophysical data analyses were carried out immediately after the earthquake. The Jiuzhaigou earthquake occurred at the intersection of the northern margin of the Minshan uplift belt and the south part of the Wenxian–Maqin fault in the south margin of the West Qinling geosyncline. There are two surface rupture zones trending northwest(NW), which are ground coseismic ruptures caused by concealed earthquake faults. The rupture on the southwest is the structure triggering the earthquake, along the Jiuzhaitiantang–Epicenter–Wuhuahai. The other one on the northeast(Shangsizhai–Zhongcha–Bimang) is a reactivation and extension of the secondary fault trending NW. The source rupture of this earthquake is a strike-slipshear fracture associated with the fault plane trending NW 331° and steeply dipping 75°, which is continuously expanding at both ends. The tectonic dynamics process of the source rupture is that the "Jiuzhaigou protrusion" is left-lateral sheared along the seismogenic fault in the NW direction. Finally, the Maqin fault and the arc fault system at the top of the "Wenxian protrusion" will be gradually broken through sometime in far future, as well as earthquaketriggered landslides will be further occurred along the narrow corridor between the seismogenic faults. The research results revealed the basic geological data and tectonic dynamic mechanism in this earthquake.
文摘Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine traffic accident mortality trends and their epidemiologic characteristics in the Kermanshah province, west of lran. Methods： In a cross sectional study, road traffic fatality data from 2004 to 2013 were analyzed to determine the epidemiological pattern of traffic accident mortality. Trend assessment was performed to ascertain the decreasing or increasing status. Chi-square and one-way analysis of variance （ANOVA） tests, as well as Poisson regression were used to determine the significance of the data in time. Data were analyzed using Excel and statistical package of SPSS version 19. Results： Out of 5110 people that died in traffic accidents, 4024 （78.7%） were males. The state of accidents indicated that 404 （43.8%） female pedestrians died as a result of car crashes, and 1330 （41.4%） males died because of car collisions. 1554 （31.9%） deaths happened to pedestrians and 1556 （32.1%） to vehicle drivers, and the rest belonged to vehicle passengers. Head trauma was the cause of death for as much as 3400 （69.9%） cases. Fatal crashes in which pedestrians were involved mostly occurred between the hours 13：00 to 15：00, while the time for vehicle drivers was between 16：00 to 18：00. 2882 people （59.1%） died before reaching to health care facilities. Traffic crash mortality trend for pedestrians follows a linear pattern with a gentle downward slope, but the trend shows various swings when it comes to vehicle drivers. Conclusion： The number of traffic crash deaths from 2004 to 2013 indicates a decreasing trend in two groups of road users： vehicle drivers and car occupants. This can be due to some interventions such as modification of traffic rules and enhancement of police control which has been implemented in recent years. Moreover, more attention should be paid to promote the optimal health care services to save the lives of the injured from traffic accidents.
