Changes in lake levels, as an indicator of climate change, are crucial for understanding water resources.Satellite altimetry has proven to be an effective technique for monitoring water level changes in inland lakes. ...Changes in lake levels, as an indicator of climate change, are crucial for understanding water resources.Satellite altimetry has proven to be an effective technique for monitoring water level changes in inland lakes. However, high-altitude and high-latitude lakes undergo seasonal freezing and melting, affecting satellite altimetry accuracy. This paper evaluates the accuracy of lake level height observations by the CryoSat-2, which uses synthetic aperture radar(SAR) across seasons. First, we used lake boundary based on optical remote sensing data to extract the footprints of CryoSat-2 that fall on Namco and Zhari Namco.After elevation conversion and anomaly identification, we obtained the time series of lake levels. These data were compared and verified against lake levels from in-situ measurements to assess the accuracy of CryoSat-2. The results show that CryoSat-2 can monitor lake level height with an accuracy of about 10-13 cm. The correlation coefficient between CryoSat-2 observations and in-situ measurements over Namco is 0.80(p < 0.01), with a Root Mean Square Error(RMSE) of 13 cm. For Zhari Namco, the correlation coefficient is 0.91, with an RMSE of 10 cm, indicating a better match. At the seasonal scale, the seasonal correlation coefficients between CryoSat-2 and in-situ measurement in Namco are 0.47(spring),0.79(summer), and 0.91(fall) with no observations available for winter. The lower correlation in spring may be due to incomplete ice melting. For Zhari Namco, the seasonal correlation coefficients are 0.89(spring), 0.93(summer), 0.89(fall), and 0.87(winter). The results show that CryoSat-2 accuracy is higher in summer and fall, while slightly lower in spring and winter, indicating that ice formation affects accuracy. Even during winter, the altimetry results do not significantly exceed the in-situ lake water level observations.展开更多
BACKGROUND Diabetic kidney disease(DKD)has become the leading cause of end-stage renal disease.The disease characteristics,morbidity,and renal function progression rate of patients with DKD are all related to sex.This...BACKGROUND Diabetic kidney disease(DKD)has become the leading cause of end-stage renal disease.The disease characteristics,morbidity,and renal function progression rate of patients with DKD are all related to sex.This suggests that sex hormones may play an important role in changing renal function in patients with diabetes.There have been only a few studies on the correlation between sex hormones and DKD,which have contradictory conclusions.AIM To investigate the relationship between circulating sex hormone levels and DKD in men and postmenopausal women with type 2 diabetes mellitus(T2DM).METHODS This retrospective cross-sectional study included 356 patients with T2DM.Pearson or Spearman rank correlation analyses assessed the relationships between sex hormone levels and renal function indices.By adjusting for age,body mass index,systolic blood pressure,diastolic blood pressure,duration of diabetes,use of sodium-glucose cotrasporter-2 inhibitor,use of glucagon-like peptide-1 receptor agonist,hypertension,use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker/angiotensin receptor-neprilysin inhibitor,diabetic retinopathy,diabetic peripheral vascular disease,triglyceride,uric acid,and hemoglobin A1c,multiple linear regression and logistic regression analyses were conducted to identify factors influencing the urinary albumin/creatinine ratio(UACR)and DKD.RESULTS In men,dehydroepiandrosterone sulfate levels were inversely associated with log-transformed UACR after adjustment for covariate factors[regression coefficient(β)=-0.691,95%confidence interval(CI):-1.241 to-0.141 for quartile 4 vs quartile 1;P=0.006 for trend].Elevated levels of estradiol were positively associated with DKD[odds ratio(OR)=3.097,95%CI:1.083-8.856 for quartile 4 vs quartile 1;P=0.041 for trend],and higher luteinizing hormone(LH)levels were similarly associated with DKD(OR=4.164,95%CI:1.30-13.330 for quartile 4 vs quartile 1;P=0.048 for trend).In postmenopausal women,LH levels were positively correlated with log-transformed UACR and DKD(β=1.039,95%CI:0.284-1.794 for quartile 4 vs quartile 1;P=0.006 for trend and OR=15.117,95%CI:2.191-104.326 for quartile 4 vs quartile 1;P=0.004 for trend).Follicle-stimulating hormone(FSH)levels were also positively associated with DKD(OR=9.588,95%CI:1.680-54.709 for quartile 4 vs quartile 1;P=0.014 for trend).CONCLUSION In men with T2DM,elevated levels of estradiol and LH levels were positively associated with increased risk of DKD.In postmenopausal women with T2DM,high FSH and LH levels were positively associated with increased risk of DKD.展开更多
Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJ...Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJTCs(heated junction thermocouples)are widely used for this purpose due to their ability to withstand extreme temperatures and radiation conditions.This article explores the role of HJTCs in reactor water level measurement and compares the performance of 2-wire and 3-wire connections.While the 2-wire connection is simple and cost-effective,it can introduce measurement inaccuracies due to wire resistance.In contrast,the 3-wire connection compensates for lead resistance,offering more precise and reliable measurements,particularly in long-distance applications.This paper discusses the operational considerations of these wiring configurations in the context of nuclear reactors and highlights the importance of choosing the appropriate connection type to optimize safety and measurement accuracy in PWR and BWR reactors.展开更多
目的:分析格列吡嗪与二甲双胍联用治疗新发初诊2型糖尿病患者的应用价值。方法:研究对象选取2024年4月至2025年4月在本院收治的102例初诊2型糖尿病患者,以信封法随机分为联合组和二甲双胍组,两组均51例,二甲双胍组予以二甲双胍治疗,联...目的:分析格列吡嗪与二甲双胍联用治疗新发初诊2型糖尿病患者的应用价值。方法:研究对象选取2024年4月至2025年4月在本院收治的102例初诊2型糖尿病患者,以信封法随机分为联合组和二甲双胍组,两组均51例,二甲双胍组予以二甲双胍治疗,联合组予以格列吡嗪联合二甲双胍治疗,两组患者均干预3 m。比较两组血糖水平、空腹C肽、餐后2 h C肽、胰岛β细胞功能指数(Homeostasis model assessment-β,HOMA-β)、胰岛抵抗指数(Homeostasis model assessment-IR,HOMA-IR),统计不良反应。结果:治疗后,联合组在降低糖化血红蛋白、空腹血糖、餐后2 h血糖方面均优于二甲双胍组(P<0.05),两组空腹及餐后2 h C肽均较治疗前有显著升高(P<0.05),且联合组空腹及餐后2 h C肽均高于二甲双胍组(P<0.05),联合组HOMA-β高于二甲双胍组(P<0.05),HOMA-IR低于二甲双胍组(P<0.05),两组不良反应比较无明显差异(P>0.05)。结论:格列吡嗪与二甲双胍联合治疗新发2型糖尿病具有协同降糖效果,能有效改善胰岛β细胞功能,安全性良好。展开更多
欧洲空间局的ENVISAT ASAR level 2算法是从合成孔径雷达(SAR)单视复图像反演涌浪方向谱的算法。该算法假设双峰海浪谱的SAR图像交叉谱是涌浪的图像交叉谱和风浪的图像交叉谱之和。实际上双峰海浪谱的SAR图像交叉谱中还有一个混合项,正...欧洲空间局的ENVISAT ASAR level 2算法是从合成孔径雷达(SAR)单视复图像反演涌浪方向谱的算法。该算法假设双峰海浪谱的SAR图像交叉谱是涌浪的图像交叉谱和风浪的图像交叉谱之和。实际上双峰海浪谱的SAR图像交叉谱中还有一个混合项,正是该混合项导致ENVI-SAT ASAR level 2算法有固有误差。利用遥感仿真的方法分析了不同海况条件下该算法的这一固有误差,结果表明,只有在有效波高较小、或风浪的成分较少、或双峰海浪的传播方向较靠近SAR距离向、或波长较长时固有误差才较小,ENVISAT ASAR level 2算法对海浪谱的反演才较为适用。展开更多
基金financial supported by National Natural Science Foundation of China (42104010, 42174097, 41974093, and 41774088)the Fundamental Research Funds for the Central Universities
文摘Changes in lake levels, as an indicator of climate change, are crucial for understanding water resources.Satellite altimetry has proven to be an effective technique for monitoring water level changes in inland lakes. However, high-altitude and high-latitude lakes undergo seasonal freezing and melting, affecting satellite altimetry accuracy. This paper evaluates the accuracy of lake level height observations by the CryoSat-2, which uses synthetic aperture radar(SAR) across seasons. First, we used lake boundary based on optical remote sensing data to extract the footprints of CryoSat-2 that fall on Namco and Zhari Namco.After elevation conversion and anomaly identification, we obtained the time series of lake levels. These data were compared and verified against lake levels from in-situ measurements to assess the accuracy of CryoSat-2. The results show that CryoSat-2 can monitor lake level height with an accuracy of about 10-13 cm. The correlation coefficient between CryoSat-2 observations and in-situ measurements over Namco is 0.80(p < 0.01), with a Root Mean Square Error(RMSE) of 13 cm. For Zhari Namco, the correlation coefficient is 0.91, with an RMSE of 10 cm, indicating a better match. At the seasonal scale, the seasonal correlation coefficients between CryoSat-2 and in-situ measurement in Namco are 0.47(spring),0.79(summer), and 0.91(fall) with no observations available for winter. The lower correlation in spring may be due to incomplete ice melting. For Zhari Namco, the seasonal correlation coefficients are 0.89(spring), 0.93(summer), 0.89(fall), and 0.87(winter). The results show that CryoSat-2 accuracy is higher in summer and fall, while slightly lower in spring and winter, indicating that ice formation affects accuracy. Even during winter, the altimetry results do not significantly exceed the in-situ lake water level observations.
基金Supported by the National Natural Science Foundation of China,No.82270942.
文摘BACKGROUND Diabetic kidney disease(DKD)has become the leading cause of end-stage renal disease.The disease characteristics,morbidity,and renal function progression rate of patients with DKD are all related to sex.This suggests that sex hormones may play an important role in changing renal function in patients with diabetes.There have been only a few studies on the correlation between sex hormones and DKD,which have contradictory conclusions.AIM To investigate the relationship between circulating sex hormone levels and DKD in men and postmenopausal women with type 2 diabetes mellitus(T2DM).METHODS This retrospective cross-sectional study included 356 patients with T2DM.Pearson or Spearman rank correlation analyses assessed the relationships between sex hormone levels and renal function indices.By adjusting for age,body mass index,systolic blood pressure,diastolic blood pressure,duration of diabetes,use of sodium-glucose cotrasporter-2 inhibitor,use of glucagon-like peptide-1 receptor agonist,hypertension,use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker/angiotensin receptor-neprilysin inhibitor,diabetic retinopathy,diabetic peripheral vascular disease,triglyceride,uric acid,and hemoglobin A1c,multiple linear regression and logistic regression analyses were conducted to identify factors influencing the urinary albumin/creatinine ratio(UACR)and DKD.RESULTS In men,dehydroepiandrosterone sulfate levels were inversely associated with log-transformed UACR after adjustment for covariate factors[regression coefficient(β)=-0.691,95%confidence interval(CI):-1.241 to-0.141 for quartile 4 vs quartile 1;P=0.006 for trend].Elevated levels of estradiol were positively associated with DKD[odds ratio(OR)=3.097,95%CI:1.083-8.856 for quartile 4 vs quartile 1;P=0.041 for trend],and higher luteinizing hormone(LH)levels were similarly associated with DKD(OR=4.164,95%CI:1.30-13.330 for quartile 4 vs quartile 1;P=0.048 for trend).In postmenopausal women,LH levels were positively correlated with log-transformed UACR and DKD(β=1.039,95%CI:0.284-1.794 for quartile 4 vs quartile 1;P=0.006 for trend and OR=15.117,95%CI:2.191-104.326 for quartile 4 vs quartile 1;P=0.004 for trend).Follicle-stimulating hormone(FSH)levels were also positively associated with DKD(OR=9.588,95%CI:1.680-54.709 for quartile 4 vs quartile 1;P=0.014 for trend).CONCLUSION In men with T2DM,elevated levels of estradiol and LH levels were positively associated with increased risk of DKD.In postmenopausal women with T2DM,high FSH and LH levels were positively associated with increased risk of DKD.
文摘Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJTCs(heated junction thermocouples)are widely used for this purpose due to their ability to withstand extreme temperatures and radiation conditions.This article explores the role of HJTCs in reactor water level measurement and compares the performance of 2-wire and 3-wire connections.While the 2-wire connection is simple and cost-effective,it can introduce measurement inaccuracies due to wire resistance.In contrast,the 3-wire connection compensates for lead resistance,offering more precise and reliable measurements,particularly in long-distance applications.This paper discusses the operational considerations of these wiring configurations in the context of nuclear reactors and highlights the importance of choosing the appropriate connection type to optimize safety and measurement accuracy in PWR and BWR reactors.
文摘目的:分析格列吡嗪与二甲双胍联用治疗新发初诊2型糖尿病患者的应用价值。方法:研究对象选取2024年4月至2025年4月在本院收治的102例初诊2型糖尿病患者,以信封法随机分为联合组和二甲双胍组,两组均51例,二甲双胍组予以二甲双胍治疗,联合组予以格列吡嗪联合二甲双胍治疗,两组患者均干预3 m。比较两组血糖水平、空腹C肽、餐后2 h C肽、胰岛β细胞功能指数(Homeostasis model assessment-β,HOMA-β)、胰岛抵抗指数(Homeostasis model assessment-IR,HOMA-IR),统计不良反应。结果:治疗后,联合组在降低糖化血红蛋白、空腹血糖、餐后2 h血糖方面均优于二甲双胍组(P<0.05),两组空腹及餐后2 h C肽均较治疗前有显著升高(P<0.05),且联合组空腹及餐后2 h C肽均高于二甲双胍组(P<0.05),联合组HOMA-β高于二甲双胍组(P<0.05),HOMA-IR低于二甲双胍组(P<0.05),两组不良反应比较无明显差异(P>0.05)。结论:格列吡嗪与二甲双胍联合治疗新发2型糖尿病具有协同降糖效果,能有效改善胰岛β细胞功能,安全性良好。
文摘欧洲空间局的ENVISAT ASAR level 2算法是从合成孔径雷达(SAR)单视复图像反演涌浪方向谱的算法。该算法假设双峰海浪谱的SAR图像交叉谱是涌浪的图像交叉谱和风浪的图像交叉谱之和。实际上双峰海浪谱的SAR图像交叉谱中还有一个混合项,正是该混合项导致ENVI-SAT ASAR level 2算法有固有误差。利用遥感仿真的方法分析了不同海况条件下该算法的这一固有误差,结果表明,只有在有效波高较小、或风浪的成分较少、或双峰海浪的传播方向较靠近SAR距离向、或波长较长时固有误差才较小,ENVISAT ASAR level 2算法对海浪谱的反演才较为适用。
