Vertical distribution changes in land cover between 1990 and 2015 within the Koshi River Basin,Centr

来源 :地理学报(英文版) | 被引量 : 0次 | 上传用户:sendan
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The study of mountain vertical natural belts is an important component in the study of regional differentiation.These areas are especially sensitive to climate change and have indicative function,which is the core of three-dimensional zonality research.Thus,based on high precision land cover and digital elevation model (DEM) data,and supported by MATLAB and ArcGIS analyses,this paper aimed to study the present situation and changes of the land cover vertical belts between 1990 and 2015 on the northern and southern slopes of the Koshi River Basin (KRB).Results showed that the vertical belts on both slopes were markedly dif-ferent from one another.The vertical belts on the southern slope were mainly dominated by cropland,forest,bare land,and glacier and snow cover.In contrast,grassland,bare land,sparse vegetation,glacier and snow cover dominated the northern slope.Study found that the main vertical belts across the KRB within this region have not changed substantially over the past 25 years.In contrast,on the southern slope,the upper limits of cropland and bare land have moved to higher elevation,while the lower limits of forest and glacier and snow cover have moved to higher elevation.The upper limit of alpine grassland on the northern slope retreated and moved to higher elevation,while the lower limits of glacier and snow cover and vegetation moved northward to higher elevations.Changes in the vertical belt were influenced by climate change and human activities over time.Cropland was mainly controlled by human activities and climate warming,and the reduced precipitation also led to the abandonment of cropland,at least to a certain extent.Changes in grassland and forest ecosystems were predominantly influenced by both human activities and climate change.At the same time,glacier and snow cover far away from human activities was also mainly influenced by climate warming.
其他文献
目的:观察利妥昔单抗(RTX)对激素依赖型肾病综合征(SDNS)患儿T淋巴细胞亚群和尿CD80水平的影响.方法:选取2016年3月至2019年10月在本院儿科肾脏病科首次接受RTX治疗的28例SDNS患儿作为研究对象(SDNS组),另外选择28例健康儿童作为对照组.SDNS患儿在糖皮质激素诱导缓解期进行1~2次RTX输注(375 mg·m-2,间隔1周).在治疗前和RTX治疗后1个月、复发时(复发亚组)或随访12个月(缓解亚组)采集外周血和尿液,采用多色流式细胞术分析外周血T、B细胞亚群;ELISA法检测
目的:分析泰州市姜堰区艾滋病的流行特征及规律,探讨相应的防治对策.方法:结合艾滋病防治基本信息系统和Excel数据库对姜堰区2001—2020年报告的HIV/AIDS病例进行统计分析.结果:姜堰区累计发现HIV/AIDS 220例,死亡27例,发病率呈逐年增长趋势(χ2=101.43,P<0.01),人群感染率为3.18/万.男性高于女性,男女比为5.29:1;已婚占72.8%;农民占50.91%;50岁及以上老年HIV/AIDS病例从2008年的16.5%上升至2020年的36.82%;样本来源于临床就
目的:分析新型冠状病毒肺炎(COVID-19)患者的咽拭子病毒载量与其血清特异性抗体水平的相关性.方法:选取2020年1月至3月在南京市第二医院汤山分院收治的19例COVID-19患者,包括7例重症感染者和12例轻症感染者.通过实时荧光逆转录聚合酶链反应动态监测其咽拭子SARS-CoV-2核酸病毒载量.利用新型冠状病毒的4种蛋白(S1、ECD、RBD和NP)作为包被抗原,ELISA方法检测患者体内针对NP、S1、RBD、ECD蛋白的特异性IgM和IgG抗体水平,并分析病毒载量与抗体之间的动态变化模式.结果
目的:建立抗早颗粒的质量标准.方法:采用薄层色谱法(TLC)对知母、枳壳、夏枯草进行定性鉴别.用高效液相色谱法(HPLC)测定盐酸小檗碱的含量.色谱柱为Phenomenex C18柱(250 mm×4.6 mm,5μm),流动相为乙腈-0.1%磷酸溶液(体积比45:55,每100 ml加十二烷基磺酸钠0.1 g),流速为1.0 ml·min-1,检测波长为265 nm,柱温为30℃.结果:TLC斑点清晰,分离好,阴性无干扰.盐酸小檗碱质量浓度在2.764~88.435μg·ml-1范围内,与峰面积线性关系
孕妇的营养摄入情况将影响子女成年后患各种慢性疾病的风险,如骨质疏松症[1-2]。研究指出,子宫内营养物质的供应将直接影响胎儿的发育,影响其生物可塑性,并可能带来长期的健康后果[3]。研究表明,孕期不良的母亲饮食方式会减少儿童的骨量,继而增加后代的骨折风险[4]。
Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This study aims to elucidate this impact and re
目的:介绍居民健康素养监测数据管理的主要内容以及利用SAS宏与Excel结合实现自动化的过程.方法:以2020年无锡市居民健康素养调查实际数据为例,利用SAS宏调用Excel参数表以实现标准操作.结果:通过将宏参数写入Excel参数表并在运行过程中利用X命令对其进行赋值,生成用于统计分析的标准化数据库.结论:本研究编写的SAS宏为健康素养监测数据管理规范操作提供了可能,也大幅提高了实际工作中数据处理的效率.
目的:探讨miR-223抑制β-淀粉样蛋白1-42(Aβ1-42)诱导海马神经元凋亡的分子机制.方法:体外培养新生SD大鼠的海马神经元,随机分为空白组(不作任何转染处理)、阴性组(转染miR-NC)、miR-223-m组(转染miR-223 mimics)、miR-223-m+LV组(转染miR-223 mimics+慢病毒骨架)、miR-223-m+LV-RhoB组(转染miR-223 mimics+RhoB过表达载体).qRT-PCR和Western blotting检测Aβ1-42诱导的海马神经元中
目的:探讨支气管哮喘患儿肺泡灌洗液(BALF)中miR-98-5p及靶蛋白STAT3表达水平与气道炎症的相关性.方法:选取2017年1月至2020年5月于重庆市涪陵区妇幼保健院就诊的120例支气管哮喘患儿作为哮喘组,包含72例急性发作期患儿(BA-E组)和48例缓解期患儿(BA-R组);纳入20例无支气管哮喘患儿为对照组.收集BALF,用实时荧光定量PCR法检测其中miR-98-5p相对表达量,采用酶联免疫吸附法检测STAT3和气道炎症因子(IL-6、IL-10、IL-13、TNF-α、总IgE),另外检
The glacier is a crucial freshwater resource in arid and semiarid regions, and the vulnerability of the glacier change is intimately linked to regional ecological services and socio-economic sustainab