电离层F2层的临界频率(f_(o)F_(2))的平方与峰值电子密度(N_(m)F2)成正比,是影响GNSS性能的关键参数之一,提升电离层f_(o)F_(2)的预测精度对于优化GNSS广播电离层模型性能并提升GNSS的定位精度具有重要意义.本文基于中国及周边区域的18...电离层F2层的临界频率(f_(o)F_(2))的平方与峰值电子密度(N_(m)F2)成正比,是影响GNSS性能的关键参数之一,提升电离层f_(o)F_(2)的预测精度对于优化GNSS广播电离层模型性能并提升GNSS的定位精度具有重要意义.本文基于中国及周边区域的18个测高仪台站和COSMIC(constellation observing system for meteorology,ionosphere,and climate)掩星观测数据,综合考虑世界时、年积日、地理位置、太阳和地磁活动等多维特征,利用随机森林(random forest,RF)算法构建了电离层f_(o)F_(2)预测模型.通过与国际参考电离层(international reference ionosphere,IRI)-2020模型对比分析,验证了该模型的预测精度.研究结果表明,与IRI国际无线电咨询委员会(International Radio Consultative Committee,CCIR)和IRI国际无线电科学联盟(International Union of Radio Science,URSI)模型相比,RF模型的平均绝对误差(mean absolute error,MAE)分别降低了14.81%和17.11%,均方根误差(root mean squared error,RMSE)分别降低了11.21%和13.14%.此外,该模型在不同纬度、地方时、太阳活动和地磁活动条件下,均展现出优于IRI-2020的预测精度.本研究不仅有效提升了中国及周边区域电离层f_(o)F_(2)的预测精度,还为提高GNSS的准确性和可靠性奠定了重要基础.展开更多
BACKGROUND The association of single nucleotide polymorphism of KCNQ1 gene rs2237895 with type 2 diabetes mellitus(T2DM)is currently controversial.It is unknown whether this association can be gene realized across dif...BACKGROUND The association of single nucleotide polymorphism of KCNQ1 gene rs2237895 with type 2 diabetes mellitus(T2DM)is currently controversial.It is unknown whether this association can be gene realized across different populations.AIM To determine the association of KCNQ1 rs2237895 with T2DM and provide reliable evidence for genetic susceptibility to T2DM.METHODS We searched PubMed,Embase,Web of Science,Cochrane Library,Medline,Baidu Academic,China National Knowledge Infrastructure,China Biomedical Literature Database,and Wanfang to investigate the association between KCNQ1 gene rs2237895 and the risk of T2DM up to January 12,2022.Review Manager 5.4 was used to analyze the association of the KCNQ1 gene rs2237895 polymorphism with T2DM and to evaluate the publication bias of the selected literature.RESULTS Twelve case–control studies(including 11273 cases and 11654 controls)met our inclusion criteria.In the full population,allelic model[odds ratio(OR):1.19;95%confidence interval(95%CI):1.09–1.29;P<0.0001],recessive model(OR:1.20;95%CI:1.11–1.29;P<0.0001),dominant model(OR:1.27.95%CI:1.14–1.42;P<0.0001),and codominant model(OR:1.36;95%CI:1.15–1.60;P=0.0003)(OR:1.22;95%CI:1.10–1.36;P=0.0002)indicated that the KCNQ1 gene rs2237895 polymorphism was significantly correlated with susceptibility to T2DM.In stratified analysis,this association was confirmed in Asian populations:allelic model(OR:1.25;95%CI:1.13–1.37;P<0.0001),recessive model(OR:1.29;95%CI:1.11–1.49;P=0.0007),dominant model(OR:1.35;95%CI:1.20–1.52;P<0.0001),codominant model(OR:1.49;95%CI:1.22–1.81;P<0.0001)(OR:1.26;95%CI:1.16–1.36;P<0.0001).In non-Asian populations,this association was not significant:Allelic model(OR:1.06,95%CI:0.98–1.14;P=0.12),recessive model(OR:1.04;95%CI:0.75–1.42;P=0.83),dominant model(OR:1.06;95%CI:0.98–1.15;P=0.15),codominant model(OR:1.08;95%CI:0.82–1.42;P=0.60.OR:1.15;95%CI:0.95–1.39;P=0.14).CONCLUSION KCNQ1 gene rs2237895 was significantly associated with susceptibility to T2DM in an Asian population.Carriers of the C allele had a higher risk of T2DM.This association was not significant in non-Asian populations.展开更多
文摘电离层F2层的临界频率(f_(o)F_(2))的平方与峰值电子密度(N_(m)F2)成正比,是影响GNSS性能的关键参数之一,提升电离层f_(o)F_(2)的预测精度对于优化GNSS广播电离层模型性能并提升GNSS的定位精度具有重要意义.本文基于中国及周边区域的18个测高仪台站和COSMIC(constellation observing system for meteorology,ionosphere,and climate)掩星观测数据,综合考虑世界时、年积日、地理位置、太阳和地磁活动等多维特征,利用随机森林(random forest,RF)算法构建了电离层f_(o)F_(2)预测模型.通过与国际参考电离层(international reference ionosphere,IRI)-2020模型对比分析,验证了该模型的预测精度.研究结果表明,与IRI国际无线电咨询委员会(International Radio Consultative Committee,CCIR)和IRI国际无线电科学联盟(International Union of Radio Science,URSI)模型相比,RF模型的平均绝对误差(mean absolute error,MAE)分别降低了14.81%和17.11%,均方根误差(root mean squared error,RMSE)分别降低了11.21%和13.14%.此外,该模型在不同纬度、地方时、太阳活动和地磁活动条件下,均展现出优于IRI-2020的预测精度.本研究不仅有效提升了中国及周边区域电离层f_(o)F_(2)的预测精度,还为提高GNSS的准确性和可靠性奠定了重要基础.
基金Supported by the Natural Science Foundation for the Higher Education Institutions of Anhui Province of China,No.2023AH050561,No.2022AH051143,No.KJ2021A0266,and No.KJ2021A1228School-level offline courses,No.2021xjkc13.
文摘BACKGROUND The association of single nucleotide polymorphism of KCNQ1 gene rs2237895 with type 2 diabetes mellitus(T2DM)is currently controversial.It is unknown whether this association can be gene realized across different populations.AIM To determine the association of KCNQ1 rs2237895 with T2DM and provide reliable evidence for genetic susceptibility to T2DM.METHODS We searched PubMed,Embase,Web of Science,Cochrane Library,Medline,Baidu Academic,China National Knowledge Infrastructure,China Biomedical Literature Database,and Wanfang to investigate the association between KCNQ1 gene rs2237895 and the risk of T2DM up to January 12,2022.Review Manager 5.4 was used to analyze the association of the KCNQ1 gene rs2237895 polymorphism with T2DM and to evaluate the publication bias of the selected literature.RESULTS Twelve case–control studies(including 11273 cases and 11654 controls)met our inclusion criteria.In the full population,allelic model[odds ratio(OR):1.19;95%confidence interval(95%CI):1.09–1.29;P<0.0001],recessive model(OR:1.20;95%CI:1.11–1.29;P<0.0001),dominant model(OR:1.27.95%CI:1.14–1.42;P<0.0001),and codominant model(OR:1.36;95%CI:1.15–1.60;P=0.0003)(OR:1.22;95%CI:1.10–1.36;P=0.0002)indicated that the KCNQ1 gene rs2237895 polymorphism was significantly correlated with susceptibility to T2DM.In stratified analysis,this association was confirmed in Asian populations:allelic model(OR:1.25;95%CI:1.13–1.37;P<0.0001),recessive model(OR:1.29;95%CI:1.11–1.49;P=0.0007),dominant model(OR:1.35;95%CI:1.20–1.52;P<0.0001),codominant model(OR:1.49;95%CI:1.22–1.81;P<0.0001)(OR:1.26;95%CI:1.16–1.36;P<0.0001).In non-Asian populations,this association was not significant:Allelic model(OR:1.06,95%CI:0.98–1.14;P=0.12),recessive model(OR:1.04;95%CI:0.75–1.42;P=0.83),dominant model(OR:1.06;95%CI:0.98–1.15;P=0.15),codominant model(OR:1.08;95%CI:0.82–1.42;P=0.60.OR:1.15;95%CI:0.95–1.39;P=0.14).CONCLUSION KCNQ1 gene rs2237895 was significantly associated with susceptibility to T2DM in an Asian population.Carriers of the C allele had a higher risk of T2DM.This association was not significant in non-Asian populations.
