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宁南旱区苜蓿草地土壤水分和根系动态分布拟合曲线特征 被引量:1
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作者 刘沛松 郝卫平 +1 位作者 李军 贾志宽 《河北农业大学学报》 CAS CSCD 北大核心 2011年第4期29-34,共6页
试验以宁南旱区3、4、6、7、10、12年生紫花苜蓿草地为研究对象,利用空间替代时间的方法,分别对紫花苜蓿的生长年限与土壤水分、根系深度和土壤干层厚度之间关系作出拟合曲线方程,以揭示土壤水分、根系和土壤干层随苜蓿生长年限变化的... 试验以宁南旱区3、4、6、7、10、12年生紫花苜蓿草地为研究对象,利用空间替代时间的方法,分别对紫花苜蓿的生长年限与土壤水分、根系深度和土壤干层厚度之间关系作出拟合曲线方程,以揭示土壤水分、根系和土壤干层随苜蓿生长年限变化的动态规律。结果表明:不同生长年限苜蓿土壤剖面含水率分布与土壤深度之间均呈二次曲线函数关系,且随生长年限变化,各函数曲线图呈有规律动态分布;苜蓿生长前10年,根系深度和土壤干层厚度分别以35.33 cm/年和91.43 cm/年的速度增加,10年后,苜蓿生长衰败,土壤干层厚度以20.77 cm/年的速度减小,干层形成速度是消退速度的4.40倍,因而苜蓿草地土壤干层一旦形成则很难恢复;第6年和第10年是苜蓿生长的两个关键年份,耗水高峰期大约在第6年,发生衰退期在第10年。建议苜蓿适宜利用年限约为6年,最迟不能超过10年。 展开更多
关键词 宁南旱区 紫花苜蓿 土壤水分 根系深度 干层厚度 拟合曲线特征
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Diagnostic value of optic disc retinal nerve fiber layer thickness for diabetic peripheral neuropathy
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作者 Xiao-hong WU Jing-wen FANG +4 位作者 Yin-qiong HUANG Xue-feng BAI Yong ZHUANG Xiao-yu CHEN Xia-hong LIN 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2020年第11期911-920,共10页
Objective:To investigate the value of optic disc retinal nerve fiber layer(RNFL)thickness in the diagnosis of diabetic peripheral neuropathy(DPN).Methods:Ninety patients with type 2 diabetes,including 60 patients with... Objective:To investigate the value of optic disc retinal nerve fiber layer(RNFL)thickness in the diagnosis of diabetic peripheral neuropathy(DPN).Methods:Ninety patients with type 2 diabetes,including 60 patients without DPN(NDPN group)and 30 patients with DPN(DPN group),and 30 healthy participants(normal group)were enrolled.Optical coherence tomography(OCT)was used to measure the four quadrants and the overall average RNFL thickness of the optic disc.The receiver operator characteristic curve was drawn and the area under the curve(AUC)was calculated to evaluate the diagnostic value of RNFL thickness in the optic disc area for DPN.Results:The RNFL thickness of the DPN group was thinner than those of the normal and NDPN groups in the overall average((101.07±12.40)μm vs.(111.07±6.99)μm and(109.25±6.90)μm),superior quadrant((123.00±19.04)μm vs.(138.93±14.16)μm and(134.47±14.34)μm),and inferior quadrant((129.37±17.50)μm vs.(143.60±12.22)μm and(144.48±14.10)μm),and the differences were statistically significant.The diagnostic efficiencies of the overall average,superior quadrant,and inferior quadrant RNFL thicknesses,and a combined index of superior and inferior quadrant RNFL thicknesses were similar,and the AUCs were 0.739(95%confidence interval(CI)0.635–0.826),0.683(95%CI 0.576–0.778),0.755(95%CI 0.652–0.840),and 0.773(95%CI 0.672–0.854),respectively.The diagnostic sensitivity of RNFL thickness in the superior quadrant reached 93.33%.Conclusions:The thickness of the RNFL in the optic disc can be used as a diagnostic method for DPN. 展开更多
关键词 Type 2 diabetes Peripheral neuropathy Retinal nerve fiber layer thickness Optical coherence tomography DIAGNOSIS
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