Taking the GY8HC well in the Gulong Sag of the Songliao Basin,NE China,as an example,this study utilized high-precision zircon U-Pb ages from volcanic ashes and AstroBayes method to estimate sedimentation rates.Throug...Taking the GY8HC well in the Gulong Sag of the Songliao Basin,NE China,as an example,this study utilized high-precision zircon U-Pb ages from volcanic ashes and AstroBayes method to estimate sedimentation rates.Through spectral analysis of high-resolution total organic carbon content(TOC),laboratory-measured free hydrocarbons(S_(1)),hydrocarbons formed during pyrolysis(S_(2)),and mineral contents,the enrichment characteristics and controlling factors of shale oil in an overmature area were investigated.The results indicate that:(1)TOC,S_(1),and S_(2)associated with shale oil enrichment exhibit a significant 173×10^(3)a obliquity amplitude modulation cycle;(2)Quartz and illite/smectite mixed-layer contents related to lithological composition show a significant 405×10^(3)a long eccentricity cycle;(3)Comparative studies with the high-maturity GY3HC well and moderate-maturity ZY1 well reveal distinct in-situ enrichment characteristics of shale oil in the overmature Qingshankou Formation,with a significant positive correlation to TOC,indicating that high TOC is a key factor for shale oil enrichment in overmature areas;(4)The sedimentary thickness of 12-13 m corresponding to the 173×10^(3)a cycle can serve as the sweet spot interval height for shale oil development in the study area,falling within the optimal fracture height range(10-15 m)generated during hydraulic fracturing of the Qingshankou shale.Orbitally forced climate changes not only controlled the sedimentary rhythms of organic carbon burial and lithological composition in the Songliao Basin but also influenced the enrichment characteristics and sweet spot distribution of Gulong shale oil.展开更多
目的:探讨骨小梁评分(trabecular bone score,TBS)联合腰椎骨密度对骨质疏松性椎体骨折的预测价值。方法:收集2023年11月至2024年5月采用双能X线吸收法行腰椎骨密度检查的1213例就诊者的病例资料进行分析。根据是否发生骨质疏松性椎体骨...目的:探讨骨小梁评分(trabecular bone score,TBS)联合腰椎骨密度对骨质疏松性椎体骨折的预测价值。方法:收集2023年11月至2024年5月采用双能X线吸收法行腰椎骨密度检查的1213例就诊者的病例资料进行分析。根据是否发生骨质疏松性椎体骨折,将受试者分为骨折组和未骨折组。采用受试者操作特征(receiver operating characteristic,ROC)曲线分析TBS和腰椎骨密度预测骨质疏松性椎体骨折的价值。结果:①分组和一般情况组间对比结果。1213例受试者中,761例表现为骨微结构受损或部分受损(TBS<1.310)、347例诊断为骨质疏松症。389例发生骨质疏松性椎体骨折(骨折组),其余824例未发生骨质疏松性椎体骨折(未骨折组)。骨折组的女性比例高于未骨折组(χ^(2)=93.584,P=0.000),年龄大于未骨折组(t=-10.186,P=0.000),体质量指数、TBS、腰椎骨密度均低于未骨折组(t=7.764,P=0.000;t=18.768,P=0.000;t=29.738,P=0.000)。②TBS和腰椎骨密度预测骨质疏松性椎体骨折价值的分析结果。ROC曲线分析结果显示,TBS、腰椎骨密度及二者联合预测骨质疏松性椎体骨折的曲线下面积分别为0.796、0.922、0.923;TBS预测骨质疏松性椎体骨折的曲线下面积小于腰椎骨密度及联合预测(Z=10.266,P=0.000;Z=-10.878,P=0.000),腰椎骨密度与联合预测骨质疏松性椎体骨折的曲线下面积的差异无统计学意义(Z=-0.970,P=0.332)。结论:TBS联合腰椎骨密度对于骨质疏松性椎体骨折具有一定的预测价值,且预测价值高于单纯应用TBS预测,但与单纯应用腰椎骨密度预测相比并无明显增益价值。展开更多
Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon de...Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon development.This study used the Theil-Sen trend analysis,Mann-Kendall trend test,coefficient of variation,Hurst index,and machine learning method(eXtreme Gradient Boosting and SHapley Additive exPlanations(XGBoost-SHAP))to analyze the spatiotemporal variation of NPP in the GPUA from 2001 to 2020 and reveal its response to climate change and human activities.The results found that during 2001-2020,the averageNPP in the GPUA showed a significant upward trend,with an annual growth rate of 10.84 g C/(m^(2)•a).The multi-year average NPP in the GPUA was 484.83 g C/(m^(2)•a),with higher values in the southwestern Qinling Mountains and lower values in the central and northeastern cropland and built-up areas.The average coefficient of variation of NPP in the GPUA was 0.14,indicating a relatively stable state overall,but 72.72%of the study area showed weak anti-persistence,suggesting that NPP in most areas may have declined in the short term.According to XGBoost-SHAP analyses,elevation,land use type and precipitation were identified as the main driving factors of NPP.Appropriate precipitation and higher temperatures promote NPP growth,whereas extreme climates,high population density,and nighttime lighting inhibit NPP.This study has important theoretical and practical significance for achieving regional sustainable development,offers a scientific basis for formulating effective ecological protection and restoration strategies,and promotes green,coordinated,and sustainable development in the GPUA.展开更多
基金Supported by the National Natural Science Foundation of China(42372162,4244205C)Project of"Solving Problems by Listing Talents"in Heilongjiang Province(2022-JS-1740,2022-JS-1853)Project on the Theory of Oil and Gas Enrichment from the Interaction of Earth's Multiple Spheres(THEMSIE04010103).
文摘Taking the GY8HC well in the Gulong Sag of the Songliao Basin,NE China,as an example,this study utilized high-precision zircon U-Pb ages from volcanic ashes and AstroBayes method to estimate sedimentation rates.Through spectral analysis of high-resolution total organic carbon content(TOC),laboratory-measured free hydrocarbons(S_(1)),hydrocarbons formed during pyrolysis(S_(2)),and mineral contents,the enrichment characteristics and controlling factors of shale oil in an overmature area were investigated.The results indicate that:(1)TOC,S_(1),and S_(2)associated with shale oil enrichment exhibit a significant 173×10^(3)a obliquity amplitude modulation cycle;(2)Quartz and illite/smectite mixed-layer contents related to lithological composition show a significant 405×10^(3)a long eccentricity cycle;(3)Comparative studies with the high-maturity GY3HC well and moderate-maturity ZY1 well reveal distinct in-situ enrichment characteristics of shale oil in the overmature Qingshankou Formation,with a significant positive correlation to TOC,indicating that high TOC is a key factor for shale oil enrichment in overmature areas;(4)The sedimentary thickness of 12-13 m corresponding to the 173×10^(3)a cycle can serve as the sweet spot interval height for shale oil development in the study area,falling within the optimal fracture height range(10-15 m)generated during hydraulic fracturing of the Qingshankou shale.Orbitally forced climate changes not only controlled the sedimentary rhythms of organic carbon burial and lithological composition in the Songliao Basin but also influenced the enrichment characteristics and sweet spot distribution of Gulong shale oil.
文摘目的:探讨骨小梁评分(trabecular bone score,TBS)联合腰椎骨密度对骨质疏松性椎体骨折的预测价值。方法:收集2023年11月至2024年5月采用双能X线吸收法行腰椎骨密度检查的1213例就诊者的病例资料进行分析。根据是否发生骨质疏松性椎体骨折,将受试者分为骨折组和未骨折组。采用受试者操作特征(receiver operating characteristic,ROC)曲线分析TBS和腰椎骨密度预测骨质疏松性椎体骨折的价值。结果:①分组和一般情况组间对比结果。1213例受试者中,761例表现为骨微结构受损或部分受损(TBS<1.310)、347例诊断为骨质疏松症。389例发生骨质疏松性椎体骨折(骨折组),其余824例未发生骨质疏松性椎体骨折(未骨折组)。骨折组的女性比例高于未骨折组(χ^(2)=93.584,P=0.000),年龄大于未骨折组(t=-10.186,P=0.000),体质量指数、TBS、腰椎骨密度均低于未骨折组(t=7.764,P=0.000;t=18.768,P=0.000;t=29.738,P=0.000)。②TBS和腰椎骨密度预测骨质疏松性椎体骨折价值的分析结果。ROC曲线分析结果显示,TBS、腰椎骨密度及二者联合预测骨质疏松性椎体骨折的曲线下面积分别为0.796、0.922、0.923;TBS预测骨质疏松性椎体骨折的曲线下面积小于腰椎骨密度及联合预测(Z=10.266,P=0.000;Z=-10.878,P=0.000),腰椎骨密度与联合预测骨质疏松性椎体骨折的曲线下面积的差异无统计学意义(Z=-0.970,P=0.332)。结论:TBS联合腰椎骨密度对于骨质疏松性椎体骨折具有一定的预测价值,且预测价值高于单纯应用TBS预测,但与单纯应用腰椎骨密度预测相比并无明显增益价值。
基金funded by the Xi'an Social Science Fund(24QL38).
文摘Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon development.This study used the Theil-Sen trend analysis,Mann-Kendall trend test,coefficient of variation,Hurst index,and machine learning method(eXtreme Gradient Boosting and SHapley Additive exPlanations(XGBoost-SHAP))to analyze the spatiotemporal variation of NPP in the GPUA from 2001 to 2020 and reveal its response to climate change and human activities.The results found that during 2001-2020,the averageNPP in the GPUA showed a significant upward trend,with an annual growth rate of 10.84 g C/(m^(2)•a).The multi-year average NPP in the GPUA was 484.83 g C/(m^(2)•a),with higher values in the southwestern Qinling Mountains and lower values in the central and northeastern cropland and built-up areas.The average coefficient of variation of NPP in the GPUA was 0.14,indicating a relatively stable state overall,but 72.72%of the study area showed weak anti-persistence,suggesting that NPP in most areas may have declined in the short term.According to XGBoost-SHAP analyses,elevation,land use type and precipitation were identified as the main driving factors of NPP.Appropriate precipitation and higher temperatures promote NPP growth,whereas extreme climates,high population density,and nighttime lighting inhibit NPP.This study has important theoretical and practical significance for achieving regional sustainable development,offers a scientific basis for formulating effective ecological protection and restoration strategies,and promotes green,coordinated,and sustainable development in the GPUA.
