Tumbleweeds participate in a common seasonal biological process in temperate grasslands,creating hanging grass fences during the grass-withering season that result in distinct ecological phenomena.In this study,we add...Tumbleweeds participate in a common seasonal biological process in temperate grasslands,creating hanging grass fences during the grass-withering season that result in distinct ecological phenomena.In this study,we addressed the urgent need to understand and restore the degraded desert steppe in Central Mongolia,particularly considering the observed vegetation edge effects around hanging grass fences.Using field surveys conducted in 2019 and 2021 in the severely degraded desert steppe of Central Mongolia,we assessed vegetation parameters and soil physical and chemical properties influenced by hanging grass fences and identified the key environmental factors affecting vegetation changes.The results indicate that the edge effects of hanging grass fences led to changes in species distributions,resulting in significant differences in species composition between the desert steppe's interior and edge areas.Vegetation parameters and soil physical and chemical properties exhibited nonlinear responses to the edge effects of hanging grass fences,with changes in vegetation coverage,aboveground biomass,and soil sand content peaking at 26.5,16.5,and 6.5 m on the leeward side of hanging grass fences,respectively.In the absence of sand dune formation,the accumulation of soil organic carbon and available potassium were identified as crucial factors driving species composition and increasing vegetation coverage.Changes in species composition and plant density were primarily influenced by soil sand content,electrical conductivity,and sand accumulation thickness.These findings suggest that hanging grass fences have the potential to alter vegetation habitats,promote vegetation growth,and control soil erosion in the degraded desert steppe of Central Mongolia.Therefore,in the degraded desert steppe,the restoration potential of hanging grass fences during the enclosure process should be fully considered.展开更多
目的比较外科治疗大隐静脉曲张的高位结扎抽剥术(high ligation and stripping,HLS)与腔内射频消融术(radio frequency ablation,RFA)在西部地区县级医院医师培训的效果及其学习曲线。方法选取2018年8月—2020年8月西吉县人民医院普通...目的比较外科治疗大隐静脉曲张的高位结扎抽剥术(high ligation and stripping,HLS)与腔内射频消融术(radio frequency ablation,RFA)在西部地区县级医院医师培训的效果及其学习曲线。方法选取2018年8月—2020年8月西吉县人民医院普通外科收治的具有外科治疗指征并同意接受治疗的100例单侧大隐静脉曲张患者的资料。采用随机数字表法将患者分为RFA组和HLS组,每组各50例。选择西吉县人民医院普通外科的1名无静脉曲张手术经验、未进行过血管彩色多普勒超声(彩超)操作的主治医师,接受海军军医大学第二附属医院(上海长征医院)血管外科专家组培训,当培训对象在专家组全程帮带下可独立主刀完成HLS和RFA手术各1例时,可参与本研究。将每组50例患者按照时间顺序划分为5个阶段(phase,P):P1(第1~10例)、P2(第11~20例)、P3(第21~30例)、P4(第31~40例)、P5(第41~50例)。P1+P2代表前期,P3代表中期,P4+P5代表后期。选择手术总时间和大隐静脉主干剥离/闭合时间作为主要观察指标。其他指标包括术前培训课时、术中出血量、切口数目、切口总长度(所有切口长度之和)、住院天数、住院费用及术后并发症发生情况。术后3个月门诊随访,观察患者是否存在隐神经损伤、残留曲张静脉,并行下肢血管彩超复查大隐静脉主干是否复通。结果HLS组和RFA组手术总时间和大隐静脉主干剥离/闭合时间的学习曲线均呈现明显下降趋势,RFA组较HLS组的下降程度更为明显。在全期(即P1至P5),HLS组的手术总时间与RFA组的差异无统计学意义(P=0.495),而大隐静脉主干剥离/闭合时间显著长于RFA组(P=0.028)。在前期,RFA组的手术总时间和大隐静脉主干剥离/闭合时间均显著长于HLS组(P值均<0.05);在中期,两组间两个时间的差异均无统计学意义(P值均>0.05);在后期,RFA组的手术总时间和大隐静脉主干剥离/闭合时间均显著短于HLS组(P值均<0.05)。RFA组需要额外进行血管超声的理论知识与操作课程的培训,故其总课时为12课时,多于HLS组的6课时。RFA组的术中出血量、切口数目均显著少于HLS组,且切口总长度、住院天数显著短于HLS组(P值均<0.05)。RFA组医保报销前、后的住院费用均显著多于HLS组(P值均<0.05)。在术后并发症方面,RFA组皮下瘀斑的发生率显著低于HLS组(P<0.05),两组隐神经损伤、残留曲张静脉的差异比均无统计学意义(P值均>0.05)。结论尽管RFA前期培训课时较长,但与HLS相比,其具备学习曲线较短、安全、简捷、有效且医疗费用低的优势,适宜在技术受限和经济条件相对落后的西部地区的县级医院开展与推广。展开更多
基金supported by the Third Xinjiang Scientific Expedition and Research Program(2021xjkk0305)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA2003020201)the Key Intergovernmental Projects for International Scientific and Technological Innovation Cooperation of the National Key Research and Development Program of China(2017YFE0109200).
文摘Tumbleweeds participate in a common seasonal biological process in temperate grasslands,creating hanging grass fences during the grass-withering season that result in distinct ecological phenomena.In this study,we addressed the urgent need to understand and restore the degraded desert steppe in Central Mongolia,particularly considering the observed vegetation edge effects around hanging grass fences.Using field surveys conducted in 2019 and 2021 in the severely degraded desert steppe of Central Mongolia,we assessed vegetation parameters and soil physical and chemical properties influenced by hanging grass fences and identified the key environmental factors affecting vegetation changes.The results indicate that the edge effects of hanging grass fences led to changes in species distributions,resulting in significant differences in species composition between the desert steppe's interior and edge areas.Vegetation parameters and soil physical and chemical properties exhibited nonlinear responses to the edge effects of hanging grass fences,with changes in vegetation coverage,aboveground biomass,and soil sand content peaking at 26.5,16.5,and 6.5 m on the leeward side of hanging grass fences,respectively.In the absence of sand dune formation,the accumulation of soil organic carbon and available potassium were identified as crucial factors driving species composition and increasing vegetation coverage.Changes in species composition and plant density were primarily influenced by soil sand content,electrical conductivity,and sand accumulation thickness.These findings suggest that hanging grass fences have the potential to alter vegetation habitats,promote vegetation growth,and control soil erosion in the degraded desert steppe of Central Mongolia.Therefore,in the degraded desert steppe,the restoration potential of hanging grass fences during the enclosure process should be fully considered.
文摘目的比较外科治疗大隐静脉曲张的高位结扎抽剥术(high ligation and stripping,HLS)与腔内射频消融术(radio frequency ablation,RFA)在西部地区县级医院医师培训的效果及其学习曲线。方法选取2018年8月—2020年8月西吉县人民医院普通外科收治的具有外科治疗指征并同意接受治疗的100例单侧大隐静脉曲张患者的资料。采用随机数字表法将患者分为RFA组和HLS组,每组各50例。选择西吉县人民医院普通外科的1名无静脉曲张手术经验、未进行过血管彩色多普勒超声(彩超)操作的主治医师,接受海军军医大学第二附属医院(上海长征医院)血管外科专家组培训,当培训对象在专家组全程帮带下可独立主刀完成HLS和RFA手术各1例时,可参与本研究。将每组50例患者按照时间顺序划分为5个阶段(phase,P):P1(第1~10例)、P2(第11~20例)、P3(第21~30例)、P4(第31~40例)、P5(第41~50例)。P1+P2代表前期,P3代表中期,P4+P5代表后期。选择手术总时间和大隐静脉主干剥离/闭合时间作为主要观察指标。其他指标包括术前培训课时、术中出血量、切口数目、切口总长度(所有切口长度之和)、住院天数、住院费用及术后并发症发生情况。术后3个月门诊随访,观察患者是否存在隐神经损伤、残留曲张静脉,并行下肢血管彩超复查大隐静脉主干是否复通。结果HLS组和RFA组手术总时间和大隐静脉主干剥离/闭合时间的学习曲线均呈现明显下降趋势,RFA组较HLS组的下降程度更为明显。在全期(即P1至P5),HLS组的手术总时间与RFA组的差异无统计学意义(P=0.495),而大隐静脉主干剥离/闭合时间显著长于RFA组(P=0.028)。在前期,RFA组的手术总时间和大隐静脉主干剥离/闭合时间均显著长于HLS组(P值均<0.05);在中期,两组间两个时间的差异均无统计学意义(P值均>0.05);在后期,RFA组的手术总时间和大隐静脉主干剥离/闭合时间均显著短于HLS组(P值均<0.05)。RFA组需要额外进行血管超声的理论知识与操作课程的培训,故其总课时为12课时,多于HLS组的6课时。RFA组的术中出血量、切口数目均显著少于HLS组,且切口总长度、住院天数显著短于HLS组(P值均<0.05)。RFA组医保报销前、后的住院费用均显著多于HLS组(P值均<0.05)。在术后并发症方面,RFA组皮下瘀斑的发生率显著低于HLS组(P<0.05),两组隐神经损伤、残留曲张静脉的差异比均无统计学意义(P值均>0.05)。结论尽管RFA前期培训课时较长,但与HLS相比,其具备学习曲线较短、安全、简捷、有效且医疗费用低的优势,适宜在技术受限和经济条件相对落后的西部地区的县级医院开展与推广。
