This paper introduces a new type of contraceptive device— Utero-Tubal Elastic Deviee (UTED). The distinguishing feature of this device is that it obstructs both fallopian tube openings at the uterine cornua. In addit...This paper introduces a new type of contraceptive device— Utero-Tubal Elastic Deviee (UTED). The distinguishing feature of this device is that it obstructs both fallopian tube openings at the uterine cornua. In addition, the device performs the action of a copper containing intrauterine device. From December 1984 to August 1988, 1061 women received UTED for a total of 18950.5 women months. 95.5% of them were followed up. The longest time of follow-up was 45 months. The net cumulative pregnaney rate was nil. The net cumulative expulsion rate was lower, and the net cumulative continuation rate was higher than that of the ordinary IUDs. The net rate of removal due to presence of symptoms approximates to the other copper containing devices. The main side effects were pain and bleeding, their occurrenee rate however, was not as high as that of other copper containing devices.展开更多
世界时与协调世界时差值(difference between universal time and coordinated universal time,UT1-UTC)是地球定向参数(Earth orientation parameters,EOP)的重要组成部分,其高精度和快速预测对全球卫星导航系统气象学、人造卫星精密...世界时与协调世界时差值(difference between universal time and coordinated universal time,UT1-UTC)是地球定向参数(Earth orientation parameters,EOP)的重要组成部分,其高精度和快速预测对全球卫星导航系统气象学、人造卫星精密轨道确定等实时应用领域至关重要。传统UT1-UTC预报方法在中长期预测中精度衰减明显,难以满足北斗导航系统及战争环境的精确制导等高精度需求。提出了一种融合地球流体有效角动量(effective angular momentum,EAM)信息的轴向分量χ_(3)数据与EOP14 C04序列的卷积长短期记忆神经网络(convolutional long short-term memory,ConvLSTM)模型预报UT1-UTC的新方法。实测数据分析结果发现,EAM轴向分量χ^(3)和经跳秒与潮汐改正后的UT1-UTC数据具有强相关性,其振幅和相位具有一致的频谱特性,说明EAM轴向分量χ^(3)是UT1-UTC的主要激发源。与参与第二届EOP预报比赛的各家精度进行对比,在90~360 d的中长期预报跨度中,ConvLSTM模型预报精度最优,改善幅度为30.27%~92.44%。对比公报A,时间跨度为60 d、180 d和360 d的中长期预报精度分别提升41.46%、70.07%和59.43%,证实了ConvLSTM能够显著改善UT1-UTC的中长期预报精度。展开更多
Universal time(UT)1 is an alternative description of the Earth’s rotation angle and is one of the spatial parameters representing the Earth’s orientation that reflects subtle changes in its rotational speed.While ve...Universal time(UT)1 is an alternative description of the Earth’s rotation angle and is one of the spatial parameters representing the Earth’s orientation that reflects subtle changes in its rotational speed.While very long baseline interferometry(VLBI)has recently achieved high-precision measurements of UT1,its prohibitively high equipment costs and complex data processes make it difficult to meet the requirements of users in fields with stringent real-time data requirements,such as astronomical measurement and celestial navigation.Currently,the digital zenith telescope is one of the most accurate ground-based optical astronomical measurement instruments available.This study briefly introduces the digital zenith telescope measurement system and the basic principles of UT1 measurement and data processing.On the basis of more than 400 UT1 measurement experiments conducted at Luonan,Lijiang,and Delingha,the accuracy of UT1 measurements based on the digital zenith telescope is analyzed.The experimental results show that the internal consistency accuracy within 20 min can reach 10 ms and that the internal consistency accuracy of single-day observations can reach 0.05″.Compared with IERS 14C04,the mean absolute error of the UT1 measurements is approximately 3 ms.This indicates that optical astronomical observations based on the digital zenith telescope can be used as an effective regional autonomous monitoring method to supplement VLBI by providing highfrequency UT1,functioning in particular as an emergency backup when satellite navigation fails.展开更多
目的通过对膝关节骨性关节炎(KOA)患者起病时和起病2年内的临床资料进行分析,旨在发现KOA早期诊断的方法及提高诊断正确率。方法对300例KOA患者的临床资料进行回顾性分析,观察患者起病时及起病2年内的主要临床症状及体征,并分析其中37...目的通过对膝关节骨性关节炎(KOA)患者起病时和起病2年内的临床资料进行分析,旨在发现KOA早期诊断的方法及提高诊断正确率。方法对300例KOA患者的临床资料进行回顾性分析,观察患者起病时及起病2年内的主要临床症状及体征,并分析其中37例行膝关节镜手术的资料。术前均行膝关节1.5 T MRI常规扫描及3.0 T MRI UTE成像检查,按分级标准分别对KOA进行分级,以关节镜下诊断为标准,对比分析2种MRI检查的诊断符合率。结果 300例KOA中,245例首发症状为膝关节冷痛,阳性率81.7%;231例关节弹响,阳性率77.0%;82例晨僵,阳性率27.3%。在膝关节体格检查中,挺髌试验阳性者143例,阳性率47.7%;髌股研磨试验阳性者125例,阳性率41.7%;膝内翻者74例,阳性率24.7%。行膝关节手术的37例关节镜分级:0级5例,Ⅰ级20例,Ⅱ级12例。以关节镜下诊断为标准,3.0 T MRI UTE成像检查与关节镜的Ⅰ级(χ2=4.497,P=0.034)、Ⅱ级(χ2=5.196,P=0.014)诊断符合率均高于1.5 T MRI常规扫描,差异有统计学意义(P<0.05)。结论早期KOA多数以膝关节冷痛为首发症状,关节弹响及晨僵也是确诊KOA的重要线索;体格检查中主要以挺髌试验及髌股研磨试验为主,同时应检查膝内翻情况;辅助检查主要依靠膝关节MRI,且运用3.0 T MRI UTE序列关节软骨成像可提高对KOA的早期确诊率。展开更多
文摘This paper introduces a new type of contraceptive device— Utero-Tubal Elastic Deviee (UTED). The distinguishing feature of this device is that it obstructs both fallopian tube openings at the uterine cornua. In addition, the device performs the action of a copper containing intrauterine device. From December 1984 to August 1988, 1061 women received UTED for a total of 18950.5 women months. 95.5% of them were followed up. The longest time of follow-up was 45 months. The net cumulative pregnaney rate was nil. The net cumulative expulsion rate was lower, and the net cumulative continuation rate was higher than that of the ordinary IUDs. The net rate of removal due to presence of symptoms approximates to the other copper containing devices. The main side effects were pain and bleeding, their occurrenee rate however, was not as high as that of other copper containing devices.
文摘世界时与协调世界时差值(difference between universal time and coordinated universal time,UT1-UTC)是地球定向参数(Earth orientation parameters,EOP)的重要组成部分,其高精度和快速预测对全球卫星导航系统气象学、人造卫星精密轨道确定等实时应用领域至关重要。传统UT1-UTC预报方法在中长期预测中精度衰减明显,难以满足北斗导航系统及战争环境的精确制导等高精度需求。提出了一种融合地球流体有效角动量(effective angular momentum,EAM)信息的轴向分量χ_(3)数据与EOP14 C04序列的卷积长短期记忆神经网络(convolutional long short-term memory,ConvLSTM)模型预报UT1-UTC的新方法。实测数据分析结果发现,EAM轴向分量χ^(3)和经跳秒与潮汐改正后的UT1-UTC数据具有强相关性,其振幅和相位具有一致的频谱特性,说明EAM轴向分量χ^(3)是UT1-UTC的主要激发源。与参与第二届EOP预报比赛的各家精度进行对比,在90~360 d的中长期预报跨度中,ConvLSTM模型预报精度最优,改善幅度为30.27%~92.44%。对比公报A,时间跨度为60 d、180 d和360 d的中长期预报精度分别提升41.46%、70.07%和59.43%,证实了ConvLSTM能够显著改善UT1-UTC的中长期预报精度。
基金supported by the National Natural Science Foundation of China(41704006,42204041,and 42374011)the Natural Science Foundation Outstanding Youth Fund Program of Henan Province(242300421150)the Key Laboratory of Smart Earth(SYS-ZX06-2024-01).
文摘Universal time(UT)1 is an alternative description of the Earth’s rotation angle and is one of the spatial parameters representing the Earth’s orientation that reflects subtle changes in its rotational speed.While very long baseline interferometry(VLBI)has recently achieved high-precision measurements of UT1,its prohibitively high equipment costs and complex data processes make it difficult to meet the requirements of users in fields with stringent real-time data requirements,such as astronomical measurement and celestial navigation.Currently,the digital zenith telescope is one of the most accurate ground-based optical astronomical measurement instruments available.This study briefly introduces the digital zenith telescope measurement system and the basic principles of UT1 measurement and data processing.On the basis of more than 400 UT1 measurement experiments conducted at Luonan,Lijiang,and Delingha,the accuracy of UT1 measurements based on the digital zenith telescope is analyzed.The experimental results show that the internal consistency accuracy within 20 min can reach 10 ms and that the internal consistency accuracy of single-day observations can reach 0.05″.Compared with IERS 14C04,the mean absolute error of the UT1 measurements is approximately 3 ms.This indicates that optical astronomical observations based on the digital zenith telescope can be used as an effective regional autonomous monitoring method to supplement VLBI by providing highfrequency UT1,functioning in particular as an emergency backup when satellite navigation fails.
文摘目的通过对膝关节骨性关节炎(KOA)患者起病时和起病2年内的临床资料进行分析,旨在发现KOA早期诊断的方法及提高诊断正确率。方法对300例KOA患者的临床资料进行回顾性分析,观察患者起病时及起病2年内的主要临床症状及体征,并分析其中37例行膝关节镜手术的资料。术前均行膝关节1.5 T MRI常规扫描及3.0 T MRI UTE成像检查,按分级标准分别对KOA进行分级,以关节镜下诊断为标准,对比分析2种MRI检查的诊断符合率。结果 300例KOA中,245例首发症状为膝关节冷痛,阳性率81.7%;231例关节弹响,阳性率77.0%;82例晨僵,阳性率27.3%。在膝关节体格检查中,挺髌试验阳性者143例,阳性率47.7%;髌股研磨试验阳性者125例,阳性率41.7%;膝内翻者74例,阳性率24.7%。行膝关节手术的37例关节镜分级:0级5例,Ⅰ级20例,Ⅱ级12例。以关节镜下诊断为标准,3.0 T MRI UTE成像检查与关节镜的Ⅰ级(χ2=4.497,P=0.034)、Ⅱ级(χ2=5.196,P=0.014)诊断符合率均高于1.5 T MRI常规扫描,差异有统计学意义(P<0.05)。结论早期KOA多数以膝关节冷痛为首发症状,关节弹响及晨僵也是确诊KOA的重要线索;体格检查中主要以挺髌试验及髌股研磨试验为主,同时应检查膝内翻情况;辅助检查主要依靠膝关节MRI,且运用3.0 T MRI UTE序列关节软骨成像可提高对KOA的早期确诊率。
