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Potassium isotopic signatures of modern offshore detrital sediments from different climatic regimes and the implications

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Science China Earth Sciences 2024年第2期67卷 405-419页

作者： Jun MU Tianyu CHEN Qian YU Shichao AN Jianfang CHEN Xuefa SHI Weiqiang LI State Key Laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing UniversityNanjing210023China Ministry of Education Key Laboratory for Coast and Island Development School of Geography and Ocean ScienceNanjing UniversityNanjing210023China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou310012China Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao266061China

Potassium isotopes are a novel tracer for continental *** K isotope studies on chemical weathering generally targeted weathering profiles under a particular climate region,yet the effects of chemical weathering on K isotopes under different climatic backgrounds remain ***,little is known about the K isotope signatures of modern unconsolidated detrital ***,we report K isotopic data of surficial seafloor sediments from continental shelves along the east coast of China(ECC),as well as those around the tropical Hainan island in the northern South China *** ECC sediments have a relatively narrow distribution ofδ^(41)K(with reference to NIST3141a)values,which range from(-0.40±0.01)‰to(-0.57±0.04)‰,with an average of(-0.51±0.09)‰.By contrast,δ^(41)K values of Hainan offshore sediments display a larger variation,ranging from(-0.28±0.07)‰to(-0.67±0.02)‰.Theδ^(41)K values of Hainan offshore sediments exhibit negative correlations with the chemical index of alteration(CIA),Al/K,Ti/K,and total iron(FeT),which underlines the control of chemical weathering on K isotopic signatures of detritus inputs into *** also measured Mg isotope compositions for the same samples;interestingly,the variability inδ^(26)Mg of the samples is small(~0.24‰)for all ECC and Hainan offshore sediments,andδ^(26)Mg values do not show clear correlations with indexes of chemical *** study demonstrates the link between K isotopic variability of detrital sediments and climatic conditions including rainfall intensity,which indicates that K isotopes of the detrital component of marine sediments could be applied to study Earth’s climate in deep ***δ^(41)K values of the offshore detrital sediments are significantly less variable than those of pelagic marine sediments,highlighting the importance of distinguishing the effects of diagenesis and neoformation of clay minerals from continental weathering in attempts to study deep-time climate-weathering

关键词： Potassium isotopes Magnesium isotopes Chemical weathering Detrital sediments Climatic regimes Mean annual precipitation

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Deep structure of the Southeast Asian curved subduction system and its dynamic process

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Journal of Oceanology and Limnology 2024年第3期42卷 701-704页

作者： Weiwei DING Key Laboratory of Submarine Geoscience&Second institute of Oceanography Ministry of Natural ResourcesHangzhou 310012China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200030China

The deep structure,material circulation,and dynamic processes in the Southeast Asia have long been an elusive scientific puzzle due to the lack of systematic scientific observations and recognized theoretical *** on the deep seismic tomography using long-period natural earthquake data,in this study,the deep structure and material circulation of the curved subduction system in Southeast Asia was studied,and the dynamic processes since 100 million years ago was *** is pointed out that challenges still exist in the precise reconstruction of deep mantle structures of the study area,the influence of multi-stage subduction on deep material exchange and shallow magma activity,as well as the spatiotemporal evolution and coupling mechanism of multi-plate *** work should focus on high-resolution land-sea joint 3-D seismic tomography imaging of the curved subduction system in the Southeast Asia,combined with geochemical analysis and geodynamic modelling works.

关键词： curved subduction system deep structure material recycling dynamic process Southeast Asia

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Exploring deep learning for landslide mapping:A comprehensive review

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China Geology 2024年第2期7卷 330-350页

作者： Zhi-qiang Yang Wen-wen Qi Chong Xu Xiao-yi Shao College of Surveying and Geo-Informatics Tongji UniversityShanghai 200092China National institute of natural Hazards Ministry of Emergency ManagementBeijing 100085China Key Laboratory of Compound and Chained natural Hazards Dynamics Ministry of Emergency Management of ChinaBeijing 100085China

A detailed and accurate inventory map of landslides is crucial for quantitative hazard assessment and land *** methods relying on change detection and object-oriented approaches have been criticized for their dependence on expert knowledge and subjective *** advancements in highresolution satellite imagery,coupled with the rapid development of artificial intelligence,particularly datadriven deep learning algorithms(DL)such as convolutional neural networks(CNN),have provided rich feature indicators for landslide mapping,overcoming previous *** this review paper,77representative DL-based landslide detection methods applied in various environments over the past seven years were *** study analyzed the structures of different DL networks,discussed five main application scenarios,and assessed both the advancements and limitations of DL in geological hazard *** results indicated that the increasing number of articles per year reflects growing interest in landslide mapping by artificial intelligence,with U-Net-based structures gaining prominence due to their flexibility in feature extraction and ***,we explored the hindrances of DL in landslide hazard research based on the above research *** such as black-box operations and sample dependence persist,warranting further theoretical research and future application of DL in landslide detection.

关键词： Landslide Mapping Quantitative hazard assessment Deep learning Artificial intelligence Neural network Big data Geological hazard survery engineering

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Research progress in assessment and strategies for sustainable food system within planetary boundaries

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Science China Earth Sciences 2024年第2期67卷 375-386页

作者： Minglei WANG Wenjiao SHI Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China

Meeting the increasing food demand in a manner that ensures both resources and environmental sustainability poses a global *** conceptual framework of planetary boundaries(PBs)has emerged as a crucial reference in the study of sustainable food system,with specific focuses on key dimensions such as land use change,freshwater use,nitrogen(N)and phosphorus(P)cycles,and greenhouse gas(GHG)*** this study,we summarized the threshold applications of PBs in sustainable food system research at both the global and national(China)*** on these thresholds,we evaluated the sustainability conditions of the food system,considering resources such as cropland,freshwater,N and P applications,as well as environmental impacts including N and P losses,and GHG *** addition,we explored the impacts of single or combined management strategies on sustainable food *** strategies included dietary changes,improvements in technologies and management,reductions in food loss and waste,and optimization in agricultural production ***,we outlined future research directions in sustainable food system,including enhancing research on the interaction mechanisms among PBs elements within food systems,conducting downscaling studies of PBs elements at national and regional levels,and ensuring the rationality of policy-making for sustainable food systems in *** study can provide a theoretical foundation and strategies guidance for sustainable food system and agricultural land use management in the future both globally and in China.

关键词： Food system Resource use Environmental impacts Sustainable strategy Planetary boundaries

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A four-band index for both liquid and solid water and its applications in the Aral Sea Basin

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Science China Earth Sciences 2024年第3期67卷 769-788页

作者： Bing YUE Xi CHEN Saibo LI Zhengping DU John WILSON Junhui YANG Yimen JIAO Shuangyan HUANG Chenghu ZHOU Xinjiang institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China institute of Geographical Sciences and natural Resources Research Chinese Academy of SciencesBeijing 100101China Spatial Sciences institute University of Southern CaliforniaLos AngelesCA 90089-0374USA

Various investigations have been conducted to analyze the water-coverage area of the Aral Sea and the Aral Sea Basin(ASB). However, the investigations incorporated considerable uncertainty and the used water indices had misclassification problem, which made different research groups present different results. Thus we first ascertain the boundaries of the ASB, the Syr and Amu river basins as well as their upper, middle and lower reaches. Then a four-band index for both liquid and solid water(ILSW) is proposed to address the misclassification problems of the classic water indices. ILSW is calculated by using the reflectance values of the green, red, near infrared, and thermal infrared bands, which combines the normalized difference water index(NDWI) and land surface temperature(LST) together. Validation results show that the ILSW water index has the highest accuracy by far in the Aral Sea Basin. Our results indicate that annual average decline of the water-coverage area was 963 km^(2) in the southern Aral Sea, whereas the northern Aral Sea has experienced little change. In the meanwhile, permanent ice and snow in upper reach of ASB has retreated considerably. Annual retreating rates of the permanent ice and snow were respectively 6233and 3841 km^(2) in upper reaches of Amu river basin(UARB) and Syr river basin(USRB). One of major reasons is that climate has become warmer in ASB. The climate change has caused serious water deficit problem. The water deficit had an increasing trend since the 1990s and its increasing rates was 3.778 billion m^(3) yearly on average. The total water deficit was 76.967 billion m^(3) on average in the whole area of ASB in the 2010s. However, up reaches of Syr river basin(USRB), a component area of ASB, had water surplus of 25.461 billion m^(3). These conclusions are useful for setting out a sustainable development strategy in ASB.

关键词： Aral Sea Basin Syr river basin Amu river basin Water indices Water-coverage area Water deficit Climate change

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Automated machine learning for rainfall-induced landslide hazard mapping in Luhe County of Guangdong Province,China

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China Geology 2024年第2期7卷 315-329页

作者： Tao Li Chen-chen Xie Chong Xu Wen-wen Qi Yuan-dong Huang Lei Li National institute of natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Key Laboratory of Compound and Chained natural Hazards Dynamics Ministry of Emergency Management of ChinaBeijing 100085China institute of Disaster Prevention Sanhe 065201China School of Emergency Management Science and Engineering University of Chinese Academy of SciencesBeijing 100049China

Landslide hazard mapping is essential for regional landslide hazard *** main objective of this study is to construct a rainfall-induced landslide hazard map of Luhe County,China based on an automated machine learning framework(AutoGluon).A total of 2241 landslides were identified from satellite images before and after the rainfall event,and 10 impact factors including elevation,slope,aspect,normalized difference vegetation index(NDVI),topographic wetness index(TWI),lithology,land cover,distance to roads,distance to rivers,and rainfall were selected as *** WeightedEnsemble model,which is an ensemble of 13 basic machine learning models weighted together,was used to output the landslide hazard assessment *** results indicate that landslides mainly occurred in the central part of the study area,especially in Hetian and *** 102.44 s were spent to train all the models,and the ensemble model WeightedEnsemble has an Area Under the Curve(AUC)value of92.36%in the test *** addition,14.95%of the study area was determined to be at very high hazard,with a landslide density of 12.02 per square *** study serves as a significant reference for the prevention and mitigation of geological hazards and land use planning in Luhe County.

关键词： Landslide hazard Heavy rainfall Harzard mapping Hazard assessment Automated machine learning Shallow landslide Visual interpretation Luhe County Geological hazards survey engineering

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Isotopic insights on quantitative assessments of interaction of eco-hydrological processes in multi-scale karst watersheds

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International Soil and Water Conservation Research 2024年第1期12卷 156-170页

作者： Zhuo Hao Yang Gao Qingwen Zhang Wen Wen Agricultural Clean Watershed Research Group Institute of Environment and Sustainable Development in AgricultureCAASBeijing100081China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing100101China School of Humanities and Social Sciences Beijing Institute of TechnologyBeijing100081China

The dynamics of hydrological processes and the storage mechanisms of karst water resources are the most important issues in karst *** impact of environmental changes on water quantity,and the evaluation and quantification of eco-hydrological processes remain poorly *** this study,high-frequency continuous monitoring in multi-scale karst watersheds in Southwest China combined the approaches of water isotopes and the hybrid single-particle lagrangian integrated trajectory(HYSPLIT)model to identify the recharge mechanisms between atmospheric vapor,rainfall,surface water,and groundwater,and to reveal the interaction of eco-hydrological *** dominant moisture sources in Puding(PD)County were the Indian Ocean(43-69%)and local moisture(24-33%).Theδ^(18)O and deuterium excess(d-excess)values showed a positive correlation indicating that secondary or sub-cloud evaporation was prominent in the wet *** water line-conditioned excess(lc-excess)indicated that karst water interacted with recent precipitation,groundwater,and evaporation across *** to its specific hydrogeological structure,surface water and rainwater have a higher contribution rate to groundwater *** Chenqi stream replenished the Houzhai River mainly in the form of groundwater,with percentages ranging from 38.1 to 93.5%in the wet season,and 47.8-80.1%in the dry *** the Houzhai outlet,surface water and groundwater interconverted frequently with a percentage of 45.6-49.1%.We believe this is the first systematic study to quantify the supply relationship between water vapor transport,rainfall,surface water and groundwater in the Chinese karst zone,making a significant move forward in the field of karst hydrological processes and improving the efficiency of water resource evaluation and management.

关键词： Stable isotope Moisture sources Water cycle Karst watersheds

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Efficient fidelity estimation: alternative derivation and related applications

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Communications in Theoretical Physics 2024年第9期76卷 18-22页

作者： Diego S Starke Marcos L W Basso Jonas Maziero Physics Department Center for Natural and Exact Sciences Federal University of Santa Maria Center for natural and Human Sciences Federal University of ABC Avenue of the States

In[***.A 107 012427 (2023)],Baldwin and Jones prove that Uhlmann–Jozsa’s fidelity between two quantum statesρandσ,i.e.,■,can be written in a simplified form as ■.In this article,we give an alternative proof of this result,using a function power series expansion and the properties of the trace *** approach not only reinforces the validity of the simplified expression but also facilitates the exploration of novel dissimilarity functions for quantum states and more complex trace functions of density operators.

关键词： Chebyshev polynomials efficient fidelity estimation Rényi entropy Ulhmann-Jozsa fidelity

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Development of an active-site titrant for SARS-CoV-2 main protease as an indispensable tool for evaluating enzyme kinetics

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Acta Pharmaceutica Sinica B 2024年第5期14卷 2349-2357页

作者： Rabea Voget Julian Breidenbach Tobias Claff Alexandra Hingst Katharina Sylvester Christian Steinebach Lan Phuong Vu Renato H.Weiße Ulrike Bartz Norbert Sträter Christa E.Müller Michael Gütschow Pharmaceutical institute Pharmaceutical&Medicinal ChemistryUniversity of BonnBonn 53121Germany institute of Bioanalytical Chemistry Center for Biotechnology and BiomedicineLeipzig UniversityLeipzig 04103Germany Department of natural Sciences University of Applied Sciences Bonn-Rhein-SiegRheinbach 53359Germany

A titrant for the SARS-CoV-2 main protease(M^(pro))was developed that enables,for the first time,the exact determination of the concentration of the enzymatically active M^(pro) by active-site *** covalent binding mode of the tetrapeptidic titrant was elucidated by the determination of the crystal structure of the enzyme–titrant *** fluorogenic substrates of M^(pro),including a prototypical,internally quenched Dabcyl-EDANS peptide,were compared in terms of solubility under typical assay *** exploiting the new titrant,key kinetic parameters for the M^(pro)-catalyzed cleavage of these substrates were determined.

关键词： COVID-19 SARS-CoV-2 Main protease Peptide nitriles Fluorogenic substrates Active-site titration X-ray crystallography Inner filter effect

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Observation of Arctic surface currents using data from a surface drifting buoy

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Acta Oceanologica Sinica 2024年第1期43卷 70-79页

作者： Hongxia Chen Lina Lin Long Fan Wangxiao Yang Yinke Dou Bingrui Li Yan He Bin Kong Guangyu Zuo Na Liu First institute of Oceanography Ministry of Natural ResourcesQingdao 266061China Laboratory for Regional Oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Key Laboratory of Marine Science and Numerical Modeling Ministry of Natural ResourcesQingdao 266061China Naval Research Academy Tianjin 300061China College of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan 030024China Polar Research institute of China Shanghai 443005China

During the 10th Chinese Arctic scientific expedition carried out in the summer of 2019,the surface current in the high-latitude areas of the Arctic Ocean was observed using a self-developed surface drifting buoy,which was initially deployed in the Chukchi *** buoy traversed the Chukchi Sea,Chukchi Abyssal Plain,Mendeleev Ridge,Makarov Basin,and Canada Basin over a period of 632 *** returning to the Mendeleev Ridge,it continued to drift toward the ***,the track of the buoy reflected the characteristics of the transpolar drift and Chukchi Slope Current,as well as the inertial flow,cross-ridge surface flow,and even the surface disorganized flow for some time *** results showed that:(1)the transpolar drift mainly occurs in the Chukchi Abyssal Plain,Mendeleev Ridge,and western Canada Basin to the east of the ridge where sea ice concentration is high,and the average northward flow velocity in the region between 79.41°N and 86.32°N was 5.1 cm/s;(2)the average surface velocity of the Chukchi Slope Current was 13.5 cm/s,and while this current moves westward along the continental slope,it also extends northwestward across the continental slope and flows to the deep sea;and(3)when sea ice concentration was less than 50%,the inertial flow was more significant(the maximum observed inertial flow was 26 cm/s,and the radius of the inertia circle was 3.6 km).

关键词： Chinese National Arctic Research Expedition(CHINARE) surface drifting buoy transpolar drift Chukchi Slope Current inertial flow

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