Biogeography of the leaflaopper subfamily Stegelytrinae Baker is studied based on an analysis of geographical distribution of this subfamily worldwide using a cluster analysis of the zoological distribution of areas o...Biogeography of the leaflaopper subfamily Stegelytrinae Baker is studied based on an analysis of geographical distribution of this subfamily worldwide using a cluster analysis of the zoological distribution of areas of endemism as well as the phylogeny of representatives of this subfamily. Results show that the Stegelytrinae mainly occur in the Oriental Region and in the Mediterranean area of the Palaearctic Region, and this extends to the east side of both Wallaee＇s and Weber＇s lines. Eleven areas of endemism of this subfamily are recognized. The proportions of endemic taxa in different areas of endemism are generally very high in comparison with other leaflaopper groups, but distinct differences could be found among the different areas of endemism of Stegelytrinae. This subfamily is most intensively diversified in the Indochina Peninsula （INCN）. This is the stegelytrine distribution center, having the highest biodiversity at both genetic and species levels. The dendrogram of endemic areas of Stegelytrinae constructed using cluster analysis of the zoological distribution of Stegelytrinae at generic level shows the endemic areas of Stegelytrinae can be divided into 4 large groups. Relationships among different endemic areas of Stegelytrinae correspond largely to the geologic history of related areas, which indicates that the evolution and vicariance of this subfamily have been closely related to the history of continental drift and climate changes. It is deduced that the presumed monophyletic Stegelytrinae originated in the Oriental Region after North America had separated from Eurasia; this is the case in the monophyletic genera group which is supported by the lateral frontal sutures extending dorsally well beyond the corresponding ocellus. In addition, two expanding traces of the Stegelytrinae are presumed, which remain plausible explanations for the dispersal of Stegelytrinae： （1） New Guinea （and probably （＋ Australia）） - Kalimantan - Sumatra - Malay Peninsula - Indochina Peninsula - Central and Southern China - （Southwestern China ＋ Nepal ＋ Northeastern India） - （Northwestern India ＋ Eastern Afghanistan）; and （2） Indochina Peninsula- Central and Southern China- （Western Asia ＋ Mediterranean Sea coastal area）.展开更多
Brick masonry constructions are very common in many areas in the world and their failure in earthquakes has been the cause of many deaths. Since human safety is main issue of disaster management, people are more conce...Brick masonry constructions are very common in many areas in the world and their failure in earthquakes has been the cause of many deaths. Since human safety is main issue of disaster management, people are more concerned about the structural assessment and strengthening of those constructions. One historical brick masonry house located in Kathmandu world heritage site is modeled by FEM （finite element method） and analyzed in E1 Centro earthquake ground motions. Bricks are modeled as solid elements and the interfaces between the brick units are modeled as zero thickness joint elements. Then, non-linear analyses of the house are applied satisfying the famous Mohr-Coulomb failure criterion. The result shows that the house is very weak and sustains large deformation in El Centro 1940 Earthquake. A strengthening solution modifying the connections of existing elements and adding wooden frame inside the house can reduce the deformations significantly.展开更多
Although seismic gap theory plays an important role in the med-and long-term earthquake prediction,the potential risk of the non-seismic gap in historical earthquake rupture areas will need to be simultaneously taken ...Although seismic gap theory plays an important role in the med-and long-term earthquake prediction,the potential risk of the non-seismic gap in historical earthquake rupture areas will need to be simultaneously taken into account in the study of med-and long-term earthquake prediction,due to the temporally clustering or non-linear behavior of large earthquake recurrence.In order to explore technical methods which can be based on observational data,and identify historical earthquake rupture zones( including the seismic gap in historical and prehistoric earthquake rupture zones),we select eight historical large earthquake rupture zones with different elapsed times on the mid-north segment of the North-South Seismic Belt to make quantitative analysis on the characteristics of modern seismicity of these zones and preliminarily explore the seismicity method for determining the urgency degree of potential earthquake hazards.The results mainly show that the pvalue,which reflects the attenuation of earthquake sequence,and the a-value,which reflects the seismicity rate,are strongly related to the elapsed time of the latest earthquake in the rupture zone.However,the corresponding relationships in some rupture areas are not clear perhaps due to the complex fault structure and faulting behavior.The b-value,which represents the state of tectonic stress accumulation,does not easily reflect the elapsed time information of different evolution stages.The b-value temporal scanning shows a steady evolution over time in most of the rupture zones,but in the rupture zone of the Wudu M8.0 earthquake of 1879,the b-value shows significant fluctuations with a decreasing trend for 20 years.By comparative analysis,we conclude that the rupture zones of the 1933 M7.5 Maoxian earthquake and the 1976 M7.2 Songpan-Pingwu earthquake are still in the decaying period of earthquake sequences,and thus do not have the background for recurrence of M7.0 earthquakes.The low b-value Maqu segment,which is located at the north margin of the rupture zone of the 842A.D.M7.0 Diebu earthquake,is more dangerous than the Diebu segment.The continuous decline of the b-value in the 1879 M8.0 Wudu earthquake rupture zone may also indicate a new round of seismogenic process.展开更多
Ecological niche modeling has emerged as an useful tool in the investigation of the phylogeographic histories of species or communities in a region. The high biodiversity （oftentimes cryptic）, and complex geography ...Ecological niche modeling has emerged as an useful tool in the investigation of the phylogeographic histories of species or communities in a region. The high biodiversity （oftentimes cryptic）, and complex geography and geological history of Southeast Asia particularly call for multipronged approaches in phylogeographic investigations. Past studies have focused on taxa that are associated with lowland rainforests, which is the dominant natural vegetation type. Here, we combine published phylogenetic data, ecological niche modeling and paleo-climate models to reveal potential drivers of divergence in two open-forest bird species, the oriental magpie-robin Copsychus saularis and Coppersmith barbet Megalaima haemacephala. In spite of broad overlap in current distributions, there are subtle differences in their climatic niches, which result in different responses to past climatic changes. For C saularis, both Last Glacial Maximum climate models indicated that the entire Sundaland was climati- cally suitable, while phylogenetic analyses found divergent eastern and western Sundaland lineages. We thus postulate that this genetic divergence was a result of past separations of coastal habitats into eastern and western portions due to the emergence of Sunda shelf as sea-level fell. The current separation of morphological subspecies in Borneo is maintained by low climatic suitability （high annual rainfall） in certain regions. The extirpation of M. haemacephala from Borneo and southern Malay Peninsula might have been driven by unsuitable conditions （high temperature seasonality） in central Sundaland and/or the lack of open woodlands. Our study shows that ecological niche modeling adds a powerful dimension to our attempt to understand lineage evolution in space [Current Zoology 61 （5）： 922-934, 2015].展开更多
基金supported by the National Natural Science Foundation of China(30970389)
文摘Biogeography of the leaflaopper subfamily Stegelytrinae Baker is studied based on an analysis of geographical distribution of this subfamily worldwide using a cluster analysis of the zoological distribution of areas of endemism as well as the phylogeny of representatives of this subfamily. Results show that the Stegelytrinae mainly occur in the Oriental Region and in the Mediterranean area of the Palaearctic Region, and this extends to the east side of both Wallaee＇s and Weber＇s lines. Eleven areas of endemism of this subfamily are recognized. The proportions of endemic taxa in different areas of endemism are generally very high in comparison with other leaflaopper groups, but distinct differences could be found among the different areas of endemism of Stegelytrinae. This subfamily is most intensively diversified in the Indochina Peninsula （INCN）. This is the stegelytrine distribution center, having the highest biodiversity at both genetic and species levels. The dendrogram of endemic areas of Stegelytrinae constructed using cluster analysis of the zoological distribution of Stegelytrinae at generic level shows the endemic areas of Stegelytrinae can be divided into 4 large groups. Relationships among different endemic areas of Stegelytrinae correspond largely to the geologic history of related areas, which indicates that the evolution and vicariance of this subfamily have been closely related to the history of continental drift and climate changes. It is deduced that the presumed monophyletic Stegelytrinae originated in the Oriental Region after North America had separated from Eurasia; this is the case in the monophyletic genera group which is supported by the lateral frontal sutures extending dorsally well beyond the corresponding ocellus. In addition, two expanding traces of the Stegelytrinae are presumed, which remain plausible explanations for the dispersal of Stegelytrinae： （1） New Guinea （and probably （＋ Australia）） - Kalimantan - Sumatra - Malay Peninsula - Indochina Peninsula - Central and Southern China - （Southwestern China ＋ Nepal ＋ Northeastern India） - （Northwestern India ＋ Eastern Afghanistan）; and （2） Indochina Peninsula- Central and Southern China- （Western Asia ＋ Mediterranean Sea coastal area）.
文摘Brick masonry constructions are very common in many areas in the world and their failure in earthquakes has been the cause of many deaths. Since human safety is main issue of disaster management, people are more concerned about the structural assessment and strengthening of those constructions. One historical brick masonry house located in Kathmandu world heritage site is modeled by FEM （finite element method） and analyzed in E1 Centro earthquake ground motions. Bricks are modeled as solid elements and the interfaces between the brick units are modeled as zero thickness joint elements. Then, non-linear analyses of the house are applied satisfying the famous Mohr-Coulomb failure criterion. The result shows that the house is very weak and sustains large deformation in El Centro 1940 Earthquake. A strengthening solution modifying the connections of existing elements and adding wooden frame inside the house can reduce the deformations significantly.
基金funded jointly by National Science&Technology Pillar Program,China(Grant No.2012BAK19B01)the Task-oriented Contract for Seismic Regime Monitoring(2010020304)
文摘Although seismic gap theory plays an important role in the med-and long-term earthquake prediction,the potential risk of the non-seismic gap in historical earthquake rupture areas will need to be simultaneously taken into account in the study of med-and long-term earthquake prediction,due to the temporally clustering or non-linear behavior of large earthquake recurrence.In order to explore technical methods which can be based on observational data,and identify historical earthquake rupture zones( including the seismic gap in historical and prehistoric earthquake rupture zones),we select eight historical large earthquake rupture zones with different elapsed times on the mid-north segment of the North-South Seismic Belt to make quantitative analysis on the characteristics of modern seismicity of these zones and preliminarily explore the seismicity method for determining the urgency degree of potential earthquake hazards.The results mainly show that the pvalue,which reflects the attenuation of earthquake sequence,and the a-value,which reflects the seismicity rate,are strongly related to the elapsed time of the latest earthquake in the rupture zone.However,the corresponding relationships in some rupture areas are not clear perhaps due to the complex fault structure and faulting behavior.The b-value,which represents the state of tectonic stress accumulation,does not easily reflect the elapsed time information of different evolution stages.The b-value temporal scanning shows a steady evolution over time in most of the rupture zones,but in the rupture zone of the Wudu M8.0 earthquake of 1879,the b-value shows significant fluctuations with a decreasing trend for 20 years.By comparative analysis,we conclude that the rupture zones of the 1933 M7.5 Maoxian earthquake and the 1976 M7.2 Songpan-Pingwu earthquake are still in the decaying period of earthquake sequences,and thus do not have the background for recurrence of M7.0 earthquakes.The low b-value Maqu segment,which is located at the north margin of the rupture zone of the 842A.D.M7.0 Diebu earthquake,is more dangerous than the Diebu segment.The continuous decline of the b-value in the 1879 M8.0 Wudu earthquake rupture zone may also indicate a new round of seismogenic process.
文摘Ecological niche modeling has emerged as an useful tool in the investigation of the phylogeographic histories of species or communities in a region. The high biodiversity （oftentimes cryptic）, and complex geography and geological history of Southeast Asia particularly call for multipronged approaches in phylogeographic investigations. Past studies have focused on taxa that are associated with lowland rainforests, which is the dominant natural vegetation type. Here, we combine published phylogenetic data, ecological niche modeling and paleo-climate models to reveal potential drivers of divergence in two open-forest bird species, the oriental magpie-robin Copsychus saularis and Coppersmith barbet Megalaima haemacephala. In spite of broad overlap in current distributions, there are subtle differences in their climatic niches, which result in different responses to past climatic changes. For C saularis, both Last Glacial Maximum climate models indicated that the entire Sundaland was climati- cally suitable, while phylogenetic analyses found divergent eastern and western Sundaland lineages. We thus postulate that this genetic divergence was a result of past separations of coastal habitats into eastern and western portions due to the emergence of Sunda shelf as sea-level fell. The current separation of morphological subspecies in Borneo is maintained by low climatic suitability （high annual rainfall） in certain regions. The extirpation of M. haemacephala from Borneo and southern Malay Peninsula might have been driven by unsuitable conditions （high temperature seasonality） in central Sundaland and/or the lack of open woodlands. Our study shows that ecological niche modeling adds a powerful dimension to our attempt to understand lineage evolution in space [Current Zoology 61 （5）： 922-934, 2015].
