查看更多>>摘要：Using historical topographic maps and aerospace remote sensing data since the 1930s,this study investigates the spatial and temporal evolution of Dongting Lake beach.The evolution charac-teristics of the beaches in different regions and the related formation mechanism were also analyzed.The results show that Dongting Lake beach expanded from 1 622.17 km2 in 1938 to 1 962.28 km2 in 2018.With the addition of 980.96 km2 of reclaimed high bay beach,the beach area increased by 1 321.07 km2.However,the change process fluctuated somewhat rather than continuously increased.Substantial expansion of the beach area occurred during 1938-1948 and 1958-1998,while slow contraction of the beach area occurred during 1948-1958 and 1998-2018.Dongting Lake beach was dominated by terrig-enous debris,the sedimentary types included lacustrine deposits,river alluvial deposits,floodplain and main channel deposits,and river-lake interaction deposits.The rapid expansion occurred in the estu-ary delta of the east branch of the Ouchi River,which advanced 38.55 km from the estuary toward the lake over the past 90 years.The causes of the changes in the beach included beach reclamation,sedi-ment changes,and lake sand mining.Seventy embankments(covering 2 057.77 km2)have been en-closed in the Dongting Lake area since 1930s,of which the high bay beach covered an area of 980.96 km2.The amount of sediment deposited in Dongting Lake has reached 230 857 x 104 m3 since 1950s,which is equivalent to an average deposition height of 0.85 m on the lake's bottom.The mining of lake sand caused the beach to shrink,and the proportion of the beach area decreased from 77.18％in 1998 to 72.60％in 2018.The results of this study provide objective data for protecting the lakeshore's eco-system and biodiversity and supporting the ecological restoration and environmental protection of the Yangtze River Basin.
José Ivan Morales-ArredondoMaría A.Armienta HernándezEduardo A.Lugo-DorantesFátima Juárez-Aparicio...
2099-2118页
查看更多>>摘要：Several aquifers located in North-Central Mexico have natural arsenic(As)concentra-tions higher than those allowed by national and international regulations;these aquifers are usually lo-cated in fractured volcanic environments that interact with sedimentary basins and have a carbonate basement.In this study,an evaluation of As in volcanic and sedimentary rocks collected at 13 sampling sites along the Sierra de Codornices(Guanajuato State,Central Mexico)was carried out.These geolog-ic materials are representative of the dominant hydrogeologic environment.The As content is dissemi-nated in volcanic rocks and the highest contents were obtained in felsic rocks;this information served to identify the hydrogeochemical processes related to the mobilization and transport of arsenic in the aquifer.The mobilization of As is a product of the dissolution of volcanic glass,a process involved in the alkaline desorption that occurs on As-containing mineral surfaces and possibly by the dissolution/desorption of Fe minerals and some clays,all these processes may be accelerated by the geothermal characteristics of the groundwater in the study area.
查看更多>>摘要：Biological classification is the foundation of biology and paleontology,as it arranges all the organisms in a hierarchy that humans can easily follow and understand.It is further used to recon-struct the evolution of life.A biological classification system(BCS)that includes all the established fos-sil taxa would be both useful and challenging for uncovering the life history.Since fossil taxa were origi-nally recorded in various published books and articles written by natural languages,the primary step is to organize all those taxa information in a manner that can be deciphered by a computer system.A Knowledge Graph(KG)is a formalized description framework of semantic knowledge,which repre-sents and retrieves knowledge in a machine-understandable way,and therefore provides an eligible method to represent the BCS.In this paper,a model of the BCS KG including the ontology and fact lay-ers is presented.To put it into practice,the ontology layer of the invertebrate fossil branches was manu-ally developed,while the fact layer was automatically constructed by extracting information from 46 volumes of the Treatise of Invertebrate Paleontology series with the help of natural language process-ing technology.As a result,27 348 taxa nodes spanning fourteen taxonomic ranks were extracted with high accuracy and high efficiency,and the invertebrate fossil branches of the BCS KG was thus in-stalled.This study demonstrates that a properly designed KG model and its automatic construction with the help of natural language processing are reliable and efficient.
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