Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what exten...Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what extent CO_(2)fertilization affects vegetation changes in such regions remains unclear.In this study,we investigated the degree to which CO_(2)fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression analysis.Results showed that CO_(2)fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO_(2)fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau region.Previous studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these changes.The findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.展开更多
目的:探讨绝经后女性骨密度(bone mineral density,BMD)与腰椎间盘退变的相关性。方法:回顾性分析2023年1月至2023年8月因腰腿痛来院治疗的95例绝经期女性。收集患者的年龄、体重、身高、体质量指数(body mass index,BMI)(kg/m^(2))、...目的:探讨绝经后女性骨密度(bone mineral density,BMD)与腰椎间盘退变的相关性。方法:回顾性分析2023年1月至2023年8月因腰腿痛来院治疗的95例绝经期女性。收集患者的年龄、体重、身高、体质量指数(body mass index,BMI)(kg/m^(2))、绝经年龄、绝经年限、高血压和糖尿病史、骨密度T值、腰椎间盘退变(lumbar disc degeneration,LDD)分级等指标。根据T值将患者分为骨量正常组、减少组及疏松组,采用Pfirrmann分级系统评估L1/2、L2/3、L3/4、L4/5、L5/S1椎间盘退变程度,并分析骨密度与腰椎间盘退变程度的相关性。结果:从总骨密度来看,疏松组的BMI显著低于减少组,减少组及疏松组的年龄、绝经年限显著高于正常组,正常组LDDⅡ级显著多于其余两组,减少组及疏松组LDDⅢ级、Ⅳ级、Ⅴ级显著多于正常组,且疏松组LDDⅤ级显著多于减少组,疏松组糖尿病者显著少于正常组(P<0.05),其余数据三组间比较差异无统计学意义。基于总腰椎骨密度分组中,疏松组在L2/3、L3/4及L1~S1水平的LDD评分显著高于其余两组(P<0.05);基于髋部BMD分组中,疏松组在L3/4及L1~S1水平的LDD评分显著高于其余两组(P<0.05)。L2/3、L3/4评分与邻近上下椎体的BMD及L1-S1评分与总腰椎BMD均呈负相关,年龄、绝经年限与LDD评分呈正相关(P<0.05)。结论:绝经后女性骨密度越低,其腰椎退变程度越严重。展开更多
基金National Natural Science Foundation of China,No.41761003The Karst Science Research Center of Guizhou Province,No.U1812401。
文摘Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what extent CO_(2)fertilization affects vegetation changes in such regions remains unclear.In this study,we investigated the degree to which CO_(2)fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression analysis.Results showed that CO_(2)fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO_(2)fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau region.Previous studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these changes.The findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.
文摘目的:探讨绝经后女性骨密度(bone mineral density,BMD)与腰椎间盘退变的相关性。方法:回顾性分析2023年1月至2023年8月因腰腿痛来院治疗的95例绝经期女性。收集患者的年龄、体重、身高、体质量指数(body mass index,BMI)(kg/m^(2))、绝经年龄、绝经年限、高血压和糖尿病史、骨密度T值、腰椎间盘退变(lumbar disc degeneration,LDD)分级等指标。根据T值将患者分为骨量正常组、减少组及疏松组,采用Pfirrmann分级系统评估L1/2、L2/3、L3/4、L4/5、L5/S1椎间盘退变程度,并分析骨密度与腰椎间盘退变程度的相关性。结果:从总骨密度来看,疏松组的BMI显著低于减少组,减少组及疏松组的年龄、绝经年限显著高于正常组,正常组LDDⅡ级显著多于其余两组,减少组及疏松组LDDⅢ级、Ⅳ级、Ⅴ级显著多于正常组,且疏松组LDDⅤ级显著多于减少组,疏松组糖尿病者显著少于正常组(P<0.05),其余数据三组间比较差异无统计学意义。基于总腰椎骨密度分组中,疏松组在L2/3、L3/4及L1~S1水平的LDD评分显著高于其余两组(P<0.05);基于髋部BMD分组中,疏松组在L3/4及L1~S1水平的LDD评分显著高于其余两组(P<0.05)。L2/3、L3/4评分与邻近上下椎体的BMD及L1-S1评分与总腰椎BMD均呈负相关,年龄、绝经年限与LDD评分呈正相关(P<0.05)。结论:绝经后女性骨密度越低,其腰椎退变程度越严重。
