In this study,we systematically explored the environmental significance of stable isotope characteristics and the controlling factors of precipitation stable isotopes in the source region of the Three Rivers(SRTR),the...In this study,we systematically explored the environmental significance of stable isotope characteristics and the controlling factors of precipitation stable isotopes in the source region of the Three Rivers(SRTR),the transitional zone of the Qinghai-Tibet Plateau in China.A total of 862 precipitation samples were collected from six fixed-point sampling locations between 2019 and 2021 in the SRTR.In June,the values of hydrogen(δD)and oxygen(δ^(18)O)stable isotopes were most enriched.The deuterium-excess(d-excess)in atmospheric precipitation was>0 in the SRTR;however,the maximum value of d-excess occurred in October.Moreover,the slopes of the local meteoric water line(LMWL)for Dari,Zaduo,Maduo,Qumalai,and Tuotuohe sites were lower than those of the global met-eoric water line(GMWL).In contrast,the slope of the LMWL for Zhimenda was higher than that of the GMWL.The altitude effects of oxygen(δ^(18)O)and hydrogen(δD)isotopes of precipitation were 0.70‰/100 m and 5.22‰/100 m,respectively.When the temperature was≤5℃,there was a significant temperature effect on stable oxygen isotope of precipitation(0.24‰/℃,P<0.05).Furthermore,even a minor increase(1%)in the weight of raindrops after falling results in a 0.82%rise in the evaporation enrichment rate ofδ^(18)O.Success-ive precipitation events also had a substantial influence on precipitation in the transitional region of the Qinghai-Tibet Plateau.The res-ults of this study provide a theoretical basis for revealing the impact mechanism of precipitation in the transitional zone of the Qinghai-Tibet Plateau under a warming climate.展开更多
A thorough understanding of the source and infiltration mechanism of soil water is of great significance to the stable supply of regional water resources and the protection of ecological environment.To solve this cruc...A thorough understanding of the source and infiltration mechanism of soil water is of great significance to the stable supply of regional water resources and the protection of ecological environment.To solve this crucial scientific problem,a total of 1980 samples of various water bodies in Qilian Mountains were collected in early,heavy and end ablation period in 2012-2019 to determine the source of soil water with endmember mixing analysis.Double isotope mass balance was used to calculate the relative contribution of piston flow and preferred flow to groundwater.The results of the study show that precipitation dominated the soil water in the study region,and it contributes 78%,89%and 91%of soil water in early,heavy and end ablation periods,respectively.Ground ice meltwater is also an important source of soil water,its contribution was 16%,11%and 7%in early,heavy and end ablation period,respectively.Snowmelt contributed to soil water only during the early(6%)and late(2%)ablation periods.Groundwater is replenished through the combined effects of preferential flow and piston flow.According to double isotope mass balance,the contribution of priority flow to shallow groundwater is 34%,45%and 34%,respectively in early,heavy and end ablation periods.This study identified the sources of soil water and water transport mechanisms in the Qilian Mountains,providing scientific and technological support for water resource conservation and sustainable utilization in cold regions.展开更多
基金Under the auspices of the National Science Foundation for Distinguished Young Scholars(No.42425107)the Science and Technology Project of Gansu Province(No.24JRRA168,23ZDKA017)+1 种基金the Key Talent Project in Gansu Province(No.2025RCXM057)National Nature Science Foundation of China(No.42107063)。
文摘In this study,we systematically explored the environmental significance of stable isotope characteristics and the controlling factors of precipitation stable isotopes in the source region of the Three Rivers(SRTR),the transitional zone of the Qinghai-Tibet Plateau in China.A total of 862 precipitation samples were collected from six fixed-point sampling locations between 2019 and 2021 in the SRTR.In June,the values of hydrogen(δD)and oxygen(δ^(18)O)stable isotopes were most enriched.The deuterium-excess(d-excess)in atmospheric precipitation was>0 in the SRTR;however,the maximum value of d-excess occurred in October.Moreover,the slopes of the local meteoric water line(LMWL)for Dari,Zaduo,Maduo,Qumalai,and Tuotuohe sites were lower than those of the global met-eoric water line(GMWL).In contrast,the slope of the LMWL for Zhimenda was higher than that of the GMWL.The altitude effects of oxygen(δ^(18)O)and hydrogen(δD)isotopes of precipitation were 0.70‰/100 m and 5.22‰/100 m,respectively.When the temperature was≤5℃,there was a significant temperature effect on stable oxygen isotope of precipitation(0.24‰/℃,P<0.05).Furthermore,even a minor increase(1%)in the weight of raindrops after falling results in a 0.82%rise in the evaporation enrichment rate ofδ^(18)O.Success-ive precipitation events also had a substantial influence on precipitation in the transitional region of the Qinghai-Tibet Plateau.The res-ults of this study provide a theoretical basis for revealing the impact mechanism of precipitation in the transitional zone of the Qinghai-Tibet Plateau under a warming climate.
基金supported by The National Science Foundation For Distinguished Young Scholars(42425107)Self-financed science and technology projects of Qinghai 906 Engineering Survey and Design Institute Co.Ltd(2024-KJ-04)+2 种基金Gansu Province Young Talent Program(2025QNGR53)Gansu Science and Technology Program(25JRRA537)the Top Talent Project of Gansu province,Chinese Academy of Sciences Young Crossover Team Project(JCTD-2022-18).
文摘A thorough understanding of the source and infiltration mechanism of soil water is of great significance to the stable supply of regional water resources and the protection of ecological environment.To solve this crucial scientific problem,a total of 1980 samples of various water bodies in Qilian Mountains were collected in early,heavy and end ablation period in 2012-2019 to determine the source of soil water with endmember mixing analysis.Double isotope mass balance was used to calculate the relative contribution of piston flow and preferred flow to groundwater.The results of the study show that precipitation dominated the soil water in the study region,and it contributes 78%,89%and 91%of soil water in early,heavy and end ablation periods,respectively.Ground ice meltwater is also an important source of soil water,its contribution was 16%,11%and 7%in early,heavy and end ablation period,respectively.Snowmelt contributed to soil water only during the early(6%)and late(2%)ablation periods.Groundwater is replenished through the combined effects of preferential flow and piston flow.According to double isotope mass balance,the contribution of priority flow to shallow groundwater is 34%,45%and 34%,respectively in early,heavy and end ablation periods.This study identified the sources of soil water and water transport mechanisms in the Qilian Mountains,providing scientific and technological support for water resource conservation and sustainable utilization in cold regions.
文摘目的 比较高孕激素状态促排卵(PPOS)方案与GnRH拮抗剂方案(GnRH-ant)在高龄患者促排卵中应用的效果。 方法 回顾性分析2017年1月至2018年10月在我院生殖医学中心行IVF/ICSI助孕的高龄女性(>35岁)临床资料,包括GnRH-ant组70例与PPOS方案组230例,比较两种方案促排卵治疗前后情况。 结果 两组患者年龄、不孕年限、BMI、AFC、基础E 2 、基础FSH、基础LH等基本资料均无明显统计学差异( P >0.05)。两组患者GnRH-ant组的HCG日E 2 水平、Gn总量和天数、胚胎数、2PN数、早发LH峰发生率及优胚率均无统计学差异( P >0.05)。GnRH拮抗剂的获卵数[(5.32±3.71)vs.(4.20±2.75)]、卵裂数[(3.69±2.95)vs.(2.95±2.33)]、优胚数[(2.32±2.05)vs.(1.80±1.67)]均显著多于PPOS组( P <0.05);GnRH-ant组的HCG日孕酮水平[(2.24±1.93)vs.(3.77±3.42)nmol/L]显著小于PPOS组( P <0.01)。 结论 本研究发现在高龄(>35岁)患者行IVF/ICSI助孕的患者中,GnRH-ant方案和PPOS方案相比较,两者在抑制早发LH峰发生率上没有明显的差异,但是GnRH-ant方案可以获得较多的优质胚胎,因此患者可能有更好的助孕结局。
