Traffic Engineering(TE)enables management of traffic in a manner that optimizes utilization of network resources in an efficient and balanced manner.However,existing TE solutions face issues relating to scalability an...Traffic Engineering(TE)enables management of traffic in a manner that optimizes utilization of network resources in an efficient and balanced manner.However,existing TE solutions face issues relating to scalability and complexity.In recent years,Segment Routing(SR)has emerged as a promising source routing paradigm.As one of the most important applications of SR,Segment Routing Traffic Engineering(SR-TE),which enables a headend to steer traffic along specific paths represented as ordered lists of instructions called segment lists,has the capability to overcome the above challenges due to its flexibility and scalability.In this paper,we conduct a comprehensive survey on SR-TE.A thorough review of SR-TE architecture is provided in the first place,reviewing the core components and implementation of SR-TE such as SR Policy,Flexible Algorithm and SR-native algorithm.Strengths of SR-TE are also discussed,as well as its major challenges.Next,we dwell on the recent SR-TE researches on routing optimization with various intents,e.g.,optimization on link utilization,throughput,QoE(Quality of Experience)and energy consumption.Afterwards,node management for SR-TE are investigated,including SR node deployment and candidate node selection.Finally,we discuss the existing challenges of current research activities and propose several research directions worth of future exploration.展开更多
Anther dehiscence controls optimal interaction between pollen and stigma,thereby determining the successful sexual reproduction.The regulators or mechanisms of this process remain elusive.Here,two CRISPR/Cas9 mutants ...Anther dehiscence controls optimal interaction between pollen and stigma,thereby determining the successful sexual reproduction.The regulators or mechanisms of this process remain elusive.Here,two CRISPR/Cas9 mutants of a rice exocyst subunit gene SEC3A,sec3a-1 and sec3a-2,showed anther indehiscence at anthesis and male sterility at maturity.Pollen viability and germination in the mutants were partly defective,whereas their female gametes undergone a normal development.Hybrid or self-pollinated seeds could be produced by artificial pollination,suggesting potential use of a weak sec3a mutant as a female line during hybrid breeding.SEC3A is widely expressed in various tissues,including anther walls.Further results showed an excessive IAA accumulation and no endothecium lignification in sec3a-1/2 anthers.Our findings suggest that SEC3A appears to regulate anther dehiscence by modulating auxin signaling,providing insights into regulation of anther dehiscence and function of exocyst in plants.展开更多
It is widely accepted that Holocene climatic and environmental changes had major impacts on socioeconomic development and the evolution of civilization.The eastern margin of the Tibetan plateau(TP)has been an importan...It is widely accepted that Holocene climatic and environmental changes had major impacts on socioeconomic development and the evolution of civilization.The eastern margin of the Tibetan plateau(TP)has been an important passageway for south‒north migration of agricultural groups since the late Neolithic.Prehistoric farmers began to occupy the northeastern Tibetan plateau(NETP)and the area of modern Yunnan Province(YNP),on the southeastern margin of the TP,from∼5200 BP and∼4600 BP,respectively.This occupation was potentially closely linked to climatic and environmental changes;however,the spatiotemporal pattern of moisture variations between these two regions,and its possible impact on human settlement and the migration of farming communities along the eastern margin of the TP during the late Neolithic and Bronze Age,are unclear.In the present study,well-dated sedimentary records with unambiguous indicators of humidity variations from the NETP and YNP were integrated,along with radiocarbon dates from human and animal bones and the remains of crop plants from archaeological sites in this region.The results indicate a long-term,out-of-phase relationship of moisture variations between the NETP and YNP during the middle to late Holocene.A mid-late Holocene increase in humidity on the NETP facilitated the development of agropastoral societies during the period of∼5200‒2200 BP.However,pronounced cooling from∼5000 BP forced the southward dispersal of millet farming groups along the eastern margin of the TP during the fifth millennium BP.Decreasing moisture in YNP promoted the expansion of an open landscape,which affected the development of agriculture during the period of∼4600‒2200 BP.Our results suggest that changes in moisture affected the development of prehistoric agriculture in the northeastern and southeastern marginal areas of the TP in different ways,implying that the development of prehistoric human society largely depended on the regional climatic conditions.展开更多
Red mud,a highly alkaline industrial solid waste generated during the production of alumina,is characterized by its fine particle size and residual heavy metals.Its massive accumulation poses a serious threat to the e...Red mud,a highly alkaline industrial solid waste generated during the production of alumina,is characterized by its fine particle size and residual heavy metals.Its massive accumulation poses a serious threat to the environment and ecosystems.This paper provided a systematic review of the current research on red mud in building materials and its potential for carbon reduction.It examined the physicochemical properties of red mud and its applications in cement-based materials,road construction,building blocks,ceramics,and composite materials.Researches indicated that utilizing red mud in building materials could significantly increase its utilization while simultaneously reducing carbon emissions during production.For instance,red mud can be employed in the production of low-clinker composite cement,used to improve the water damage resistance of asphalt mixtures,and integrated to enhance the mechanical properties and durability of unfired bricks and ceramic products.Moreover,its carbon sequestration capacity offered substantial support for developing carbon-reducing building materials.Nonetheless,the large-scale application of red mud remains constrained by critical technical challenges,including high pre-treatment costs,limited performance optimization,and insufficient environmental safety assessments.This paper outlined future research directions and proposes strategies to promote the extensive utilization of red mud for carbon reduction,thereby providing a theoretical framework and technical support for the green transformation of the aluminum industry.展开更多
The evolution of the human living environment on the Tibetan Plateau(TP)and its influence on human activities is a major scientific issue of multidisciplinary interest.Based on published research on past environmental...The evolution of the human living environment on the Tibetan Plateau(TP)and its influence on human activities is a major scientific issue of multidisciplinary interest.Based on published research on past environmental changes on the TP,we synthesize changes in landscape and other environmental components,including temperature,moisture,vegetation,and aeolian activity,on the glacial-interglacial and the Holocene suborbital timescales.This synthesis elucidates the processes,patterns,and mechanisms of environmental changes on the TP,on multiple timescales.We also explore the possible impacts of environmental changes on prehistoric human activities by combining chronological data from archaeological sites since the Paleolithic with the latest advances in archaeology,genetics,linguistics,and archaeobotany.Our findings indicate the following:(1)On a glacialinterglacial timescale,the environmental evolution of the TP exhibits a high spatiotemporal consistency,characterized by cold and dry conditions with sparse vegetation during glacial periods,and warm and humid conditions with flourishing vegetation during interglacial periods.(2)On the Holocene suborbital timescale,summer temperatures on the TP generally show a Holocene thermal maximum.However,reconstructions of mean annual temperature changes vary,likely due to factors including seasonal biases and regional differences in mean annual temperature proxies.In terms of moisture,the northern TP(especially the northeastern TP),which is influenced by both the summer monsoon and the westerly circulation,shows increased moisture since the early Holocene,in contrast to decreasing moisture in the southern monsoon-dominated parts.This constitutes a northsouth dipolar pattern of Holocene moisture changes.Furthermore,a series of abrupt climate events occurred on the TP during the Holocene,while there were pronounced regional differences in the environmental response to North Atlantic cooling events.Regarding terrestrial ecosystems,pollen assemblages reveal that vegetation succession on the TP generally responded to summer monsoon changes,with forest vegetation retreating and steppe/meadow vegetation expanding during the Holocene.Records of aeolian activity and paleosol development indicate that the northeastern TP experienced the most intensive aeolian activity in the early Holocene,while paleosol development was the most active during the middle-late Holocene.However,the spatiotemporal patterns of aeolian activity on the southern TP remain unclear.(3)On the glacial-interglacial timescale,prehistoric humans tended to spread from adjacent areas onto the TP during the relatively warm and biologically rich interglacials,while the harsh living environment during glacial periods restricted further exploration of the TP.(4)Promoted by the warmer and wetter climate and the expansion of millet agriculture in the Yellow River Basin,human activity on the northeastern TP intensified significantly during the early-middle Holocene.During 6.0–5.0 ka,the favorable climatic conditions promoted millet agriculture which resulted in the intensification of human activity on the northeastern TP.However,the gradual cooling after~5.0 ka forced prehistoric human groups to migrate southward.During~4.2–3.6 ka,significant cooling events led to reduced human activity and the transformation of subsistence strategies.The establishment of a mixed arable-pastoral economy became the primary driver for the rapid expansion of the spatial range of human settlement and the intensity of human activity since~3.6 ka.Additionally,since 3.6 ka,increasing moisture on the northeastern TP and decreasing moisture on the southern TP promoted the development of agriculture and pastoralism in different ways in these regions,suggesting that the development of prehistoric human societies remained heavily dependent on regional climatic conditions.This study has important implications for understanding the relationship between environmental changes and human activities on the TP,and it helps address the challenges posed by future climate change,as well as contributing to China's“Belt and Road”initiative.展开更多
Machine learning(ML)is widely applied to accelerate materials design and discovery due to its outperforming capability of data analysis and information extraction.However,experimental and computational errors typicall...Machine learning(ML)is widely applied to accelerate materials design and discovery due to its outperforming capability of data analysis and information extraction.However,experimental and computational errors typically lead to emerging data anomalies,harming the performance of ML models.Most currently used anomaly detection methods are purely data-driven,which has limited capability of learning complicated factors in materials data.Here,we propose a domain knowledge-assisted data anomaly detection(DKA-DAD)workflow,where materials domain knowledge is encoded as symbolic rules.Three detection models are designed for evaluating the correctness of individual descriptor value,correlation between descriptors,and similarity between samples,respectively,and one modification model is constructed for comprehensive governance.We construct 180 synthetic datasets by injecting noise into 60 structured materials datasets collected from materials ML studies,to validate its potential utility and applications.DKA-DAD achieves a 12%F1-score improvement in anomaly detection accuracy on synthetic datasets compared to purely data-driven approach and the ML models trained on materials datasets processed through DKA exhibit an average 9.6%improvement in R^(2)for the property prediction.Our work provides a data anomaly detecting approach under the guidance of materials domain knowledge towards accelerating materials design and discovery based on ML.展开更多
The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. g...The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.展开更多
Micro RNAs(miRNAs)are key regulators of gene expression in many important biological processes of plants.However,few miRNAs have been shown to regulate seed vigor.Here,we conducted microarray assays to analyze miRNA e...Micro RNAs(miRNAs)are key regulators of gene expression in many important biological processes of plants.However,few miRNAs have been shown to regulate seed vigor.Here,we conducted microarray assays to analyze miRNA expression levels in seeds of the rice(Oryza sativa L.)cultivar ZR02.Results showed significant differences in the expression of 11 miRNAs between artificially aged and untreated control seeds.Among these,osa-miR164c was transcriptionally upregulated,while osamiR168 a was downregulated in artificially aged seeds;this was verified by quantitative real-time PCR analysis.Under the same aging condition,osa-miR164c overexpression in OE164c transgenic seeds and osa-miR168a silencing in MIM168a transgenic seeds of the rice cultivar Kasalath led to lower germination rates,whereas osa-miR164c silencing Rin MIM164c and osa-miR168a overexpression in OE168a resulted in higher seed germination rates compared with wild-type seeds.Meanwhile,changes in cytomembrane permeability of seeds and in the expression level of osa-miR164c target genes(OsPM27 and OsPSK5)and osamiR168a target genes(OsAGO1 and OsPTR2)under aging conditions coincided with changes in seed vigor induced by osa-miR164c and osa-miR168 a.Thus,genetic manipulation of miRNAs has important implications in the development of crop cultivars with high vigor and extended life span of seeds.展开更多
The ecological environment of the Tibetan Plateau,known as the“Third Pole of the Earth”,is extremely sensitive and fragile.With rapid societal development,environmental problems on the Tibetan Plateau have become pr...The ecological environment of the Tibetan Plateau,known as the“Third Pole of the Earth”,is extremely sensitive and fragile.With rapid societal development,environmental problems on the Tibetan Plateau have become prominent,as it is downwind of the emission sources from densely populated areas in the Middle East and South Asia,and the plateau has become one of the regions significantly affected by transboundary pollutant transmission(including black carbon,BC).The Tibetan Plateau has a long history of life and religious sacrifices,including aromatic plant-burning,which were recorded in the geologic record;therefore,BC can be used as a potential indicator to study the changes in religious activities.In this study,BC analysis was carried out based on the plausible dating framework tested by the AMS14C and137Cs methods on successive sediment cores from Lake Dalzong,an alpine lake in the Gannan Tibetan Autonomous Prefecture,northeast of the Tibetan Plateau.It was found that the BC in the lake sediments mainly accumulated through proximity wet deposition,and its content changes reflected the prevalence of surrounding religious activities.The study results indicate that the area of Lake Dalzong has experienced three periods of enhanced religious activities in the last millennium:1490-1565 CE(mid-Ming Dynasty),1810-1890 CE(late Qing Dynasty),and 1920 CE to the present(since the founding of the Republic of China),and the increase in religious activities on this centennial time scale is a response to concurrent social development.This study is the first to extract information on the variation in religious activities from lake sediments on the Tibetan Plateau,which will help advance the study of the historical context of the Anthropocene on the Tibetan Plateau.展开更多
Reconstructing Holocene temperature evolution is important for understanding present temperature variations and for predicting future climate change,in the context of global warming.The evolution of Holocene global te...Reconstructing Holocene temperature evolution is important for understanding present temperature variations and for predicting future climate change,in the context of global warming.The evolution of Holocene global temperature remains disputed,due to differences between proxy reconstructions and model simulations,a discrepancy known as the῾Holocene temperature conundrum᾽.More reliable and quantitative terrestrial temperature records are needed to resolve the spatial heterogeneity of existing records.In this study,based on the analysis of branched glycerol dialkyl glycerol tetraethers(brGDGTs)from a loess-paleosol sequence from the Ganjia Basin in the north-eastern Tibetan Plateau(NETP),we quantitatively reconstructed the mean annual air temperature(MAAT)over the past 12 ka.The MAAT reconstruction shows that the temperature remained low during the early Holocene(12−8 ka),followed by a rapid warming at around 8 ka.From 8 to 4 ka,the MAAT record reached its highest level,followed by a cooling trend from the late Holocene(4−0 ka).The variability of the reconstructed MAAT is consistent with trends of annual temperature records from the Tibetan Plateau(TP)during the Holocene.We attribute the relatively low temperatures during the early Holocene to the existence of ice sheets at high-latitude regions in the Northern Hemisphere and the weaker annual mean insolation at 35°N.During the mid to late Holocene,the long-term cooling trend in the annual temperature record was primarily driven by declining summer insolation.This study provides key geological evidence for clarifying Holocene temperature change in the TP.展开更多
1Introduction.The Tibetan Plateau(TP)is the largest and highest terrain on the Earth,comprising more than 80%of continents higher than 4000 m above sea level.The extremely high elevation resulted in cold and arid clim...1Introduction.The Tibetan Plateau(TP)is the largest and highest terrain on the Earth,comprising more than 80%of continents higher than 4000 m above sea level.The extremely high elevation resulted in cold and arid climate,sparse vegetation,limited available water resources,thin oxygen on TP,as well as desolated landscape,which makes it one of the most unfriendly habitable places on the Earth.However,ancient humans lived on TP as early as 200 thousand years ago(Chen et al.,2019;Zhang et al.,2020),and developed ancient civilizations,including the Tibetan Empire,Guge Kingdom in historical periods.展开更多
Erratum to:Front.Earth Sci.DOI 10.1007/s11707-023-1094-6 The original version of this article unfortunately contained a mistake.The presentation of was incorrect.The corrected figure is given below.
基金partially supported by Chinese National Research Fund(NSFC)No.62172189 and 61772235Natural Science Foundation of Guangdong Province No.2020A1515010771Science and Technology Program of Guangzhou No.202002030372.
文摘Traffic Engineering(TE)enables management of traffic in a manner that optimizes utilization of network resources in an efficient and balanced manner.However,existing TE solutions face issues relating to scalability and complexity.In recent years,Segment Routing(SR)has emerged as a promising source routing paradigm.As one of the most important applications of SR,Segment Routing Traffic Engineering(SR-TE),which enables a headend to steer traffic along specific paths represented as ordered lists of instructions called segment lists,has the capability to overcome the above challenges due to its flexibility and scalability.In this paper,we conduct a comprehensive survey on SR-TE.A thorough review of SR-TE architecture is provided in the first place,reviewing the core components and implementation of SR-TE such as SR Policy,Flexible Algorithm and SR-native algorithm.Strengths of SR-TE are also discussed,as well as its major challenges.Next,we dwell on the recent SR-TE researches on routing optimization with various intents,e.g.,optimization on link utilization,throughput,QoE(Quality of Experience)and energy consumption.Afterwards,node management for SR-TE are investigated,including SR node deployment and candidate node selection.Finally,we discuss the existing challenges of current research activities and propose several research directions worth of future exploration.
基金supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(32171970)the Chongqing Outstanding Scientists Project(cstc2022ycjh-bgzxm0073)the Natural Science Foundation of Chongqing,China(cstc2021jcyj-cxttX0004)。
文摘Anther dehiscence controls optimal interaction between pollen and stigma,thereby determining the successful sexual reproduction.The regulators or mechanisms of this process remain elusive.Here,two CRISPR/Cas9 mutants of a rice exocyst subunit gene SEC3A,sec3a-1 and sec3a-2,showed anther indehiscence at anthesis and male sterility at maturity.Pollen viability and germination in the mutants were partly defective,whereas their female gametes undergone a normal development.Hybrid or self-pollinated seeds could be produced by artificial pollination,suggesting potential use of a weak sec3a mutant as a female line during hybrid breeding.SEC3A is widely expressed in various tissues,including anther walls.Further results showed an excessive IAA accumulation and no endothecium lignification in sec3a-1/2 anthers.Our findings suggest that SEC3A appears to regulate anther dehiscence by modulating auxin signaling,providing insights into regulation of anther dehiscence and function of exocyst in plants.
基金supported by the National Key R&D Program of China(2021YFC1523600)Major Project of National Social Science Foundation of China(21&ZD285).
文摘It is widely accepted that Holocene climatic and environmental changes had major impacts on socioeconomic development and the evolution of civilization.The eastern margin of the Tibetan plateau(TP)has been an important passageway for south‒north migration of agricultural groups since the late Neolithic.Prehistoric farmers began to occupy the northeastern Tibetan plateau(NETP)and the area of modern Yunnan Province(YNP),on the southeastern margin of the TP,from∼5200 BP and∼4600 BP,respectively.This occupation was potentially closely linked to climatic and environmental changes;however,the spatiotemporal pattern of moisture variations between these two regions,and its possible impact on human settlement and the migration of farming communities along the eastern margin of the TP during the late Neolithic and Bronze Age,are unclear.In the present study,well-dated sedimentary records with unambiguous indicators of humidity variations from the NETP and YNP were integrated,along with radiocarbon dates from human and animal bones and the remains of crop plants from archaeological sites in this region.The results indicate a long-term,out-of-phase relationship of moisture variations between the NETP and YNP during the middle to late Holocene.A mid-late Holocene increase in humidity on the NETP facilitated the development of agropastoral societies during the period of∼5200‒2200 BP.However,pronounced cooling from∼5000 BP forced the southward dispersal of millet farming groups along the eastern margin of the TP during the fifth millennium BP.Decreasing moisture in YNP promoted the expansion of an open landscape,which affected the development of agriculture during the period of∼4600‒2200 BP.Our results suggest that changes in moisture affected the development of prehistoric agriculture in the northeastern and southeastern marginal areas of the TP in different ways,implying that the development of prehistoric human society largely depended on the regional climatic conditions.
基金funded by National Natural Science Foundation of China(grant No.51368015)for the project“Study on the Viscosity Reduction Mechanism and Road Performance of Red Mud-Modified Asphalt Mixture Based on Electronic Theory”Science and Technology Project of the Department of Education of Jiangxi Province(grant No.GJJ201902).
文摘Red mud,a highly alkaline industrial solid waste generated during the production of alumina,is characterized by its fine particle size and residual heavy metals.Its massive accumulation poses a serious threat to the environment and ecosystems.This paper provided a systematic review of the current research on red mud in building materials and its potential for carbon reduction.It examined the physicochemical properties of red mud and its applications in cement-based materials,road construction,building blocks,ceramics,and composite materials.Researches indicated that utilizing red mud in building materials could significantly increase its utilization while simultaneously reducing carbon emissions during production.For instance,red mud can be employed in the production of low-clinker composite cement,used to improve the water damage resistance of asphalt mixtures,and integrated to enhance the mechanical properties and durability of unfired bricks and ceramic products.Moreover,its carbon sequestration capacity offered substantial support for developing carbon-reducing building materials.Nonetheless,the large-scale application of red mud remains constrained by critical technical challenges,including high pre-treatment costs,limited performance optimization,and insufficient environmental safety assessments.This paper outlined future research directions and proposes strategies to promote the extensive utilization of red mud for carbon reduction,thereby providing a theoretical framework and technical support for the green transformation of the aluminum industry.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFC1523600)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0601)。
文摘The evolution of the human living environment on the Tibetan Plateau(TP)and its influence on human activities is a major scientific issue of multidisciplinary interest.Based on published research on past environmental changes on the TP,we synthesize changes in landscape and other environmental components,including temperature,moisture,vegetation,and aeolian activity,on the glacial-interglacial and the Holocene suborbital timescales.This synthesis elucidates the processes,patterns,and mechanisms of environmental changes on the TP,on multiple timescales.We also explore the possible impacts of environmental changes on prehistoric human activities by combining chronological data from archaeological sites since the Paleolithic with the latest advances in archaeology,genetics,linguistics,and archaeobotany.Our findings indicate the following:(1)On a glacialinterglacial timescale,the environmental evolution of the TP exhibits a high spatiotemporal consistency,characterized by cold and dry conditions with sparse vegetation during glacial periods,and warm and humid conditions with flourishing vegetation during interglacial periods.(2)On the Holocene suborbital timescale,summer temperatures on the TP generally show a Holocene thermal maximum.However,reconstructions of mean annual temperature changes vary,likely due to factors including seasonal biases and regional differences in mean annual temperature proxies.In terms of moisture,the northern TP(especially the northeastern TP),which is influenced by both the summer monsoon and the westerly circulation,shows increased moisture since the early Holocene,in contrast to decreasing moisture in the southern monsoon-dominated parts.This constitutes a northsouth dipolar pattern of Holocene moisture changes.Furthermore,a series of abrupt climate events occurred on the TP during the Holocene,while there were pronounced regional differences in the environmental response to North Atlantic cooling events.Regarding terrestrial ecosystems,pollen assemblages reveal that vegetation succession on the TP generally responded to summer monsoon changes,with forest vegetation retreating and steppe/meadow vegetation expanding during the Holocene.Records of aeolian activity and paleosol development indicate that the northeastern TP experienced the most intensive aeolian activity in the early Holocene,while paleosol development was the most active during the middle-late Holocene.However,the spatiotemporal patterns of aeolian activity on the southern TP remain unclear.(3)On the glacial-interglacial timescale,prehistoric humans tended to spread from adjacent areas onto the TP during the relatively warm and biologically rich interglacials,while the harsh living environment during glacial periods restricted further exploration of the TP.(4)Promoted by the warmer and wetter climate and the expansion of millet agriculture in the Yellow River Basin,human activity on the northeastern TP intensified significantly during the early-middle Holocene.During 6.0–5.0 ka,the favorable climatic conditions promoted millet agriculture which resulted in the intensification of human activity on the northeastern TP.However,the gradual cooling after~5.0 ka forced prehistoric human groups to migrate southward.During~4.2–3.6 ka,significant cooling events led to reduced human activity and the transformation of subsistence strategies.The establishment of a mixed arable-pastoral economy became the primary driver for the rapid expansion of the spatial range of human settlement and the intensity of human activity since~3.6 ka.Additionally,since 3.6 ka,increasing moisture on the northeastern TP and decreasing moisture on the southern TP promoted the development of agriculture and pastoralism in different ways in these regions,suggesting that the development of prehistoric human societies remained heavily dependent on regional climatic conditions.This study has important implications for understanding the relationship between environmental changes and human activities on the TP,and it helps address the challenges posed by future climate change,as well as contributing to China's“Belt and Road”initiative.
基金supported in part by the National Natural Science Foundation of China(Nos.92270124,92472207 and 52073169)National Key Research and Development Program of China(No.2021YFB3802101).
文摘Machine learning(ML)is widely applied to accelerate materials design and discovery due to its outperforming capability of data analysis and information extraction.However,experimental and computational errors typically lead to emerging data anomalies,harming the performance of ML models.Most currently used anomaly detection methods are purely data-driven,which has limited capability of learning complicated factors in materials data.Here,we propose a domain knowledge-assisted data anomaly detection(DKA-DAD)workflow,where materials domain knowledge is encoded as symbolic rules.Three detection models are designed for evaluating the correctness of individual descriptor value,correlation between descriptors,and similarity between samples,respectively,and one modification model is constructed for comprehensive governance.We construct 180 synthetic datasets by injecting noise into 60 structured materials datasets collected from materials ML studies,to validate its potential utility and applications.DKA-DAD achieves a 12%F1-score improvement in anomaly detection accuracy on synthetic datasets compared to purely data-driven approach and the ML models trained on materials datasets processed through DKA exhibit an average 9.6%improvement in R^(2)for the property prediction.Our work provides a data anomaly detecting approach under the guidance of materials domain knowledge towards accelerating materials design and discovery based on ML.
基金supported by the National Natural Science Foundation of China (Grant No. 41842050)
文摘The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.
基金funded by the National Natural Science Foundation of China(31270348,31671773,31500200,and 31470285)Special R&D Program for Constructing Shanxi Agriculture Valley(SXNGJSKYZX201702)+2 种基金Hunan Provincial Construct Program of the Key Discipline in Ecology(0713)Hunan Provincial Cooperative Innovation Center of Engineering and New Products for Developmental Biology(20134486)Natural Science Foundation of Shanxi Province(2014011004-1)。
文摘Micro RNAs(miRNAs)are key regulators of gene expression in many important biological processes of plants.However,few miRNAs have been shown to regulate seed vigor.Here,we conducted microarray assays to analyze miRNA expression levels in seeds of the rice(Oryza sativa L.)cultivar ZR02.Results showed significant differences in the expression of 11 miRNAs between artificially aged and untreated control seeds.Among these,osa-miR164c was transcriptionally upregulated,while osamiR168 a was downregulated in artificially aged seeds;this was verified by quantitative real-time PCR analysis.Under the same aging condition,osa-miR164c overexpression in OE164c transgenic seeds and osa-miR168a silencing in MIM168a transgenic seeds of the rice cultivar Kasalath led to lower germination rates,whereas osa-miR164c silencing Rin MIM164c and osa-miR168a overexpression in OE168a resulted in higher seed germination rates compared with wild-type seeds.Meanwhile,changes in cytomembrane permeability of seeds and in the expression level of osa-miR164c target genes(OsPM27 and OsPSK5)and osamiR168a target genes(OsAGO1 and OsPTR2)under aging conditions coincided with changes in seed vigor induced by osa-miR164c and osa-miR168 a.Thus,genetic manipulation of miRNAs has important implications in the development of crop cultivars with high vigor and extended life span of seeds.
基金supported by the National Natural Science Foundation of China(Grant Nos.42171150,42130502)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0601)。
文摘The ecological environment of the Tibetan Plateau,known as the“Third Pole of the Earth”,is extremely sensitive and fragile.With rapid societal development,environmental problems on the Tibetan Plateau have become prominent,as it is downwind of the emission sources from densely populated areas in the Middle East and South Asia,and the plateau has become one of the regions significantly affected by transboundary pollutant transmission(including black carbon,BC).The Tibetan Plateau has a long history of life and religious sacrifices,including aromatic plant-burning,which were recorded in the geologic record;therefore,BC can be used as a potential indicator to study the changes in religious activities.In this study,BC analysis was carried out based on the plausible dating framework tested by the AMS14C and137Cs methods on successive sediment cores from Lake Dalzong,an alpine lake in the Gannan Tibetan Autonomous Prefecture,northeast of the Tibetan Plateau.It was found that the BC in the lake sediments mainly accumulated through proximity wet deposition,and its content changes reflected the prevalence of surrounding religious activities.The study results indicate that the area of Lake Dalzong has experienced three periods of enhanced religious activities in the last millennium:1490-1565 CE(mid-Ming Dynasty),1810-1890 CE(late Qing Dynasty),and 1920 CE to the present(since the founding of the Republic of China),and the increase in religious activities on this centennial time scale is a response to concurrent social development.This study is the first to extract information on the variation in religious activities from lake sediments on the Tibetan Plateau,which will help advance the study of the historical context of the Anthropocene on the Tibetan Plateau.
基金supported by the National Natural Science Foundation of China(Grant Nos.42171150 and 42130502)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0601).
文摘Reconstructing Holocene temperature evolution is important for understanding present temperature variations and for predicting future climate change,in the context of global warming.The evolution of Holocene global temperature remains disputed,due to differences between proxy reconstructions and model simulations,a discrepancy known as the῾Holocene temperature conundrum᾽.More reliable and quantitative terrestrial temperature records are needed to resolve the spatial heterogeneity of existing records.In this study,based on the analysis of branched glycerol dialkyl glycerol tetraethers(brGDGTs)from a loess-paleosol sequence from the Ganjia Basin in the north-eastern Tibetan Plateau(NETP),we quantitatively reconstructed the mean annual air temperature(MAAT)over the past 12 ka.The MAAT reconstruction shows that the temperature remained low during the early Holocene(12−8 ka),followed by a rapid warming at around 8 ka.From 8 to 4 ka,the MAAT record reached its highest level,followed by a cooling trend from the late Holocene(4−0 ka).The variability of the reconstructed MAAT is consistent with trends of annual temperature records from the Tibetan Plateau(TP)during the Holocene.We attribute the relatively low temperatures during the early Holocene to the existence of ice sheets at high-latitude regions in the Northern Hemisphere and the weaker annual mean insolation at 35°N.During the mid to late Holocene,the long-term cooling trend in the annual temperature record was primarily driven by declining summer insolation.This study provides key geological evidence for clarifying Holocene temperature change in the TP.
文摘1Introduction.The Tibetan Plateau(TP)is the largest and highest terrain on the Earth,comprising more than 80%of continents higher than 4000 m above sea level.The extremely high elevation resulted in cold and arid climate,sparse vegetation,limited available water resources,thin oxygen on TP,as well as desolated landscape,which makes it one of the most unfriendly habitable places on the Earth.However,ancient humans lived on TP as early as 200 thousand years ago(Chen et al.,2019;Zhang et al.,2020),and developed ancient civilizations,including the Tibetan Empire,Guge Kingdom in historical periods.
文摘Erratum to:Front.Earth Sci.DOI 10.1007/s11707-023-1094-6 The original version of this article unfortunately contained a mistake.The presentation of was incorrect.The corrected figure is given below.
