食管鳞癌患者根治性放疗预后列线图模型的构建—泛京津冀多中心回顾分析(3JECROG R-03A)

目的:构建列线图(nomogram)模型以预测食管鳞癌患者的预后情况,指导个体化治疗。方法:回顾性分析2002年1月至2016年12月国内10家放疗中心(泛京津冀食管癌协作组-3JECROG)收治的2680例根治性放疗食管鳞癌患者资料,随机分为训练组和验证组,根据训练组的预后因素构建nomogram模型,并进行训练组内部和验证组外部验证。分别以nomogram模型与AJCC/UICC分期评估两组患者预后及临床获益。结果:全组1、3、5年生存率分别为69.0%、37.7%、31.0%。多因素分析肿瘤部位、TNM分期、原发肿瘤体积和是否同步化疗是影响食管癌的独立预后因素(均P<0.05)。在训练组和验证组中nomogram模型的一致性指数(C-index)、AUC值均高于AJCC/UICC分期(均P<0.001)。基于nomogram模型分为低、中、高风险亚组与AJCC/UICC分期比较,nomogram模型的生存曲线之间具有显著性差异(P<0.001),且1、3、5年的总生存临床决策曲线(decision curve analysis,DCA)下面积均具有显著性差异。结论:本研究构建的nomogram模型较AJCC/UICC分期具有更好的预测能力,有助于食管癌患者的预后判断及指导个体化治疗。

营养免疫炎性指标预测免疫联合放化疗二线治疗食管鳞癌患者预后的价值

目的:评估营养免疫炎性指标用于预测接受camrelizumab联合放(化)疗二线治疗复发和(或)转移转移食管鳞癌(relapsed or metastatic esophageal squamous cell carcinoma,R/M ESCC)患者预后的价值。方法:从2018年1月至2021年3月,从河北医科大学第四医院筛选出48例符合入组标准的R/M ESCC患者进行回顾性分析,根据受试者工作特征曲线(receiver operating characteristic curve,ROC)确定预后营养指数(prognostic nutritional index,PNI)、中性粒细胞淋巴细胞比(neutrophilic-tolymphocyte ratio,NLR)、血小板与淋巴细胞比(platelet-to-lymphocyte ratio,PLR)和全身免疫-炎症指数(systemic immune-inflammation index,SII)这4项指标预测患者预后的最佳临界值。应用SPSS 25.0版本软件进行单因素和多因素统计学分析。结果:全组患者二线免疫治疗后的1、2年生存(overall survival,OS)率和无进展生存(progression-free survival,PFS)率分别为42.9%、22.5%和29.0%、5.8%;中位OS和PFS分别为9.0个月(95%CI:6.4~11.7)和8.5个月(95%CI:1.5~5.6)。多因素分析结果显示免疫联合方式、近期疗效、PNI、NLR、PLR和SII为患者OS的独立影响因素(P=0.044、0.030、<0.001、0.040、0.044、0.036);免疫联合方式、使用免疫周期数、近期疗效、PNI、NLR、PLR和SII为患者PFS的独立影响因素(P=0.049、0.024、0.003、0.017、0.008、<0.001、0.009)。结论:低PNL,高NLR、PLR和SII值为接受camrelizumab联合放(化)疗二线治疗R/M ESCC预后较差的独立性预测指标。

肺大细胞神经内分泌癌的精准治疗

精准医学的发展正在改变癌症的诊疗方式,分子靶点的不断探索及新的药物和疗效数据涌现,为癌症患者带来生机。肺大细胞神经内分泌癌(large cell neuroendocrine carcinoma of the lung,LCNEC)是相对罕见的肿瘤,也在精准医学的蓬勃发展中迎来曙光。近年来,基因组和转录组分析揭示了LCNEC的不同亚型,为个性化的治疗带来希望。在靶向治疗方面,已有关于LCNEC携带EGFR、ALK、BRAF V600E突变位点的患者从靶向治疗中获益的报道,PI3K-AKT-MTOR通路、BDNF/TrkB信号通路的探索及抗体偶联物(antibody-drug conjugate,ADC)药物研究为LCNEC靶向治疗提供了新方向。免疫治疗方面,程序性死亡受体-1(programmed cell death protein-1,PD-1)及其配体(programmed cell death protein-ligand 1,PD-L1)抑制剂、PD-1/细胞毒性T淋巴细胞相关抗原(cytotoxic T lymphocyte antigen 4,CTLA-4)双抗在LCNEC中的应用已有研究,在后线缺乏治疗方案时,可考虑选择免疫治疗。尽管有关LCNEC患者应用免疫治疗及靶向治疗获得长期生存获益的病例被持续报道,但仍有待前瞻性及大样本研究确定其在LCNEC中的治疗价值。

Evaluation of ASTER GDEM in the northeastern margin of Tibetan Plateau in gravity reduction

In this paper, we first transferred the normal height of ASTER GDEM v2 to GPS ellipsoidal height based on the EGM96, and analyzed the precision of this digital elevation model in the northeastern margin of Tibetan Plateau （NETP） combining with 89 ground GPS measurements. The results demonstrate that the standard deviation of the difference between ASTER GDEM and GPS results is 9.3 m, and the precision of ASTER GDEM in this region is approximately 10 m. We also calculated the free-air gravity anomalies using the relative gravity data and DEM model in NETP. The results show that the gravity anomalies are generally negative with local positive values, ranging from -156 to 43 reGal （10-5 m/s2）. At last, we compared the EGM2008 free-air gravity anomalies （FGAs） with the ground gravity measurements, and their spatial patterns are similar. While the point-to-point difference between the modeling and measuring results shows great discrepancy. The free-air gravity anomalies of EGM2008 in this region range from -154 to 96 mGal, and the difference between EGM2008 and the ground measurements ranges from -102 to 50 regal. The mean difference is -17.34 mGal, and the standard deviation is 46.69 mGal, which demonstrates that the EGM2008 has poor precision in the northeastern margin of Tibet Plateau.

不同照射野对达完全缓解食管鳞癌患者失败模式影响的分析

目的:探讨食管鳞癌患者接受不同照射野治疗后的失败模式,尤其是经治疗后达完全缓解(complete remission,CR)患者的复发及进展情况。方法:收集2011年1月至2014年12月于河北医科大学第四医院接受根治性放(化)疗的食管鳞癌患者701例,对符合入组条件的食管鳞癌患者进行回顾性分析,首先分析全组患者的总生存率和复发率;其次分析接受选择性淋巴结照射(elective nodal irradiation,ENI)和累及野照射(involved-field irradiation,IFI)这两组患者的复发情况及其复发部位的差异;接着分析不同治疗疗效患者复发情况及ENI和IFI两组治疗后达CR患者复发部位的差异;同时对影响全组患者出现复发的独立性因素进行多因素分析;最后对ENI和IFI两组患者的构成比进行倾向得分匹配(propensity score matching,PSM)分析,并进一步比较PSM后两组患者的复发的差异,且分析影响PSM后患者发的独立性因素。采用SPSS19.0统计软件进行统计分析。结果:患者1、3、5年复发率分别为27.6%、52.2%和59.4%,中位复发时间为11.6个月。IFI和ENI组复发率分别为47.3%和49.2%,差异无统计学意义(χ^(2)=0.182,P=0.670)。IFI与ENI两组患者复发部位有显著性差异(χ^(2)=10.372,P=0.006)。IFI与ENI两组患者近期疗效有显著性差异(χ^(2)=13.385,P=0.001);ENI和IFI中达CR患者的总体复发率(31.7%vs.45.2%)差异无统计学意义(χ^(2)=3.167,P=0.075)、复发部位差异亦无统计学意义(χ^(2)=3.457,P=0.178)。PSM分析后每组均为172例患者,两组患者总体复发率差异无统计学意义(χ^(2)=0.570,P=0.450),但复发部位有显著性差异(χ^(2)=110.513,P=0.005);IFI与ENI两组患者近期疗效有显著性差异(χ^(2)=7.226,P=0.027),PSM后与ENI组CR患者相比,IFI组CR患者的复发率(53.3%vs.对29.5%)显著性升高(χ^(2)=6.145,P=0.013),且两组患者复发部位亦有显著性差异(χ^(2)=7.467,P=0.024);近期疗效和食管癌病变部位为影响PSM后患者出现复发的独立性因素(P=0.014,0.018)。结论:ENI与IFI患者的总治疗失败率无显著性差异,但其复发部位存在显著性差异,与IFI组治疗后CR患者相比,ENI组患者的照射野外复发率显著性下降,但野内复发率较高。最终结论需要精心设计的、更大的多中心前瞻性试验结果来证实。

Impact and Analysis of Prognostic Factors in Patients with Non-Metastatic Esophageal Squamous Cell Carcinoma: A Retrospective Single Institution Study

Objective: To investigate the impact of local tumor factors on the prognosis of non-metastatic esophageal squamous cell carcinoma patients. Methods: We performed a retrospective analysis of data from 278 consecutive esophageal squamous cell carcinoma patients between January 2009 and December 2016. The prognosis factors such as the GTV volume, GTV maximum diameter, and GTV length were analyzed. Results: The results of ROC curve analysis showed that prognosis critical values of the GTV volume, GTV maximum diameter, and GTV length were 27.98 cm3, 1.80 and 5.85 cm, respectively. The result of the univariate analysis showed that the GTV volume (P = 0.0184), GTV maximum diameter (P = 0.0246), and GTV length (P = 0.0035) were the prognostic factors for overall survival;the barium meal length (P = 0.0149) was the prognostic factor for local control. The multivariate analysis showed that the barium meal length (P = 0.0013), GTV maximum diameter (P = 0.0047), and GTV length (P = 0.0032) as the independent prognostic factors associated with overall survival;the barium meal length (P = 0.0037) was the only independent prognostic factors for local control. Conclusion: The esophageal lesion length was the main prognosis factor for patients with non-metastatic esophageal squamous cell carcinoma. Therefore, we suggest that the physician must give enough attention to these patients in clinical practice, and give active treatment.

Surface seasonal mass changes and vertical crustal deformation in North China from GPS and GRACE measurements

The Earth is an elastic body,and the surface mass loading changes will lead to elastic loading deformation on the surface of the Earth.In this study,we investigated the surface seasonal mass changes and vertical crustal deformation in North China using the data obtained by the techniques of the Global Positioning System(GPS),Gravity Recovery and Climate Experiment(GRACE)and Surface Loading Models(SLMs).The seasonal annual signal and semi-annual signal obtained by the three techniques show strong correlations.The average value of the weighted root-mean-square(WRMS)of the all 30 sites is 58%after deducting the GRACE-obtained vertical deformation from the GPS-derived vertical deformation.However,the consistency of results between GPS and SLMs is not so good,with a 31%mean WRMS reduction,due to the fact that the global SLMs perform not well in North China.The GRACEmeasured long-term trend is deducted from the GPS-obtained vertical rates to reveal the crustal displacement caused by the underground factors such as tectonic movement and groundwater in North China.The results show that the rates of stations HECX and TJBH are very large,more than 10 mm/yr,which suggests that the surface subsidence is caused by excessive exploitation of groundwater.

Detection of different-time-scale signals in the length of day variation based on EEMD analysis technique

Scientists pay great attention to different-time-scale signals in the lengllh of day （LOD） variations △LOD, which provide signatures of the Earth＇s interior structure, couplings among different layers, and potential excitations of ocean and atmosphere. In this study, based on the ensemble empirical mode decomposition （EEMD）, we analyzed the latest time series of △LOD data spanning from January 1962 to March 2015. We observed the signals with periods and amplitudes of about 0.5 month and 0.19 ms, 1.0 month and 0.19 ms, 0.5 yr and 0.22 ms, 1.0 yr and 0.18 ms, 2.28 yr and 0.03 ms, 5.48 yr and 0.05 ms, respectively, in coincidence with the results of predecessors. In addition, some signals that were previously not definitely observed by predecessors were detected in this study, with periods and amplitudes of 9.13 d and 0.12 ms, 13.69 yr and 0.10 ms, respectively. The mechanisms of the LOD fluctuations of these two signals are still open.

Determination of the geopotential and orthometric height based on frequency shift equation

The orthometric height (OH) system plays a key role in geodesy, and it has broad applications in various fields and activities. Based on general relativity theory (GRT), on an arbitrary equi-geo- potential surface, there does not exist the gravity frequency shift of an electromagnetic wave signal. However, between arbitrary two different equi-geopotential surfaces, there exists the gra- vity frequency shift of the signal. The relationship between the geopotential difference and the gravity frequency shift between arbitrary two points P and Q is referred to as the gravity frequency shift equation. Based on this equation, one can determine the geopotential difference as well as the OH difference between two separated points P and Q either by using electromagnetic wave signals propagated between P and Q, or by using the Global Positioning System (GPS) satellite signals received simultaneously by receivers at P and Q. Suppose an emitter at P emits a signal with frequency f towards a receiver at Q, and the received frequency of the signal at Q is , or suppose an emitter on board a flying GPS satellite emits signals with frequency f towards two receivers at P and Q on ground, and the received frequencies of the signals at P and Q are and , respectively, then, the geopoten-tial dif- ference between these two points can be determined based on the geopotential frequen- cy shift equation, using either the gravity frequency shift ? f or ? , and the corresponding OH difference is further determined based on the Bruns’ formula. Besides, using this approach a unified world height datum system might be realized, because P and Q could be chosen quite arbitrarily, e.g., they are located on two separated continents or islands.

Earth rotation deceleration/acceleration due to semidiurnal oceanic/atmospheric tides:Revisited with new calculation

The global oceanic/atmospheric tides exert decelerating/accelerating secular torques on the Earth rotation. We developed new formulations to accurately calculate amounts of two kinds of secular tidal torques. After Melchior, we found that an additional factor 1+k-l = 1.216, which has been formerly neglected, must be multiplied unto the tidal torque integral. By using our refined formulations and the recent oceanic/atmospheric global tide models, we found that:(i) semidiurnal oceanic lunar/solar tides exert decelerating torques of about-4.462 × 10^(16)/-0.676 × 10^(16) Nm respectively and(ii) atmospheric S_2 tide exerts accelerating torque of 1.55 × 10^(15) Nm. Former estimates of the atmospheric S_2 tidal torque were twice as large as our estimate due to improper consideration of loading effect. We took the load Love number for atmospheric loading effect from Guo et al.(2004). For atmospheric loading of spherical harmonic degree two, the value of k′=-0.6031 is different from that for ocean loading as k′ =-0.3052,while the latter is currently used for both cases-ocean/atmospheric loading-without distinction. We discuss(i) the amount of solid Earth tidal dissipation(which has been left most uncertain) and(ii) secular changes of the dynamical state of the Earth-Moon-Sun system. Our estimate of the solid Earth tidal torque is-4.94×10^(15) Nm.

The effect of large reservoirs impoundment to the spatial and temporal variations of regional crustal deformation in Hubei Province, China

The total capacity of Three Gorges Reservoir（TGR） and Danjiangkou Reservoir（DJR） is large and has significant seasonal fluctuations, which give rise to crustal instability. In this research, we focus on studying the temporal and spatial variation of crustal deformation in Hubei Province caused by reservoir impoundment of TGR and DJR.The Digital Elevation Model, historical hydrological information, GPS monitoring data and load-induced deformation model are combined to monitor the crustal deformation. The modeled results indicate that in the trapezoidal area between the TGR and DJR, the average vertical deformations at different latitudes have different variation tendencies. The vertical deformation modulus and fluctuation amplitude are larger at the latitude of 33 N/32.5 N from 2003 to 2006 and at the latitude of 31 N/32.5 N from 2008 to 2014, while the latter are much larger than the former. Moreover, from2008 to 2014, the frequency and the intensity of seismic activities are all enhanced significantly in this region. The modeled results at the GPS sites are consistent with the vertical displacement of GPS monitoring results in trends and the waveform. It can be inferred that the seasonal deformation is elastic. The horizontal deformation components have the same variation trends with that at each GPS monitoring station,which demonstrates that the whole region is moving toward the southeast. The spatial variation of crustal deformation demonstrates that the impoundment of TGR in2003 causes significant vertical displacements, with the maximum modulus of 32 mm downward located in Xiangjiang River＇s estuary. When the water storage increases, the maximum value will become larger, and the location will move toward the upstream.Besides, the earthquakes occurred more frequently in the region with maximum deformation modulus.

Multichannel singular spectrum analysis of the axial atmospheric angular momentum

Earth＇s variable rotation is mainly produced by the variability of the AAM（atmospheric angular momentum）. In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in the Earth＇s rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD（length of day） were described. We applied MSSA（Multichannel Singular Spectrum Analysis） jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-mo nth, quasi-biennial, 5-year, and low-frequency oscillations. PCs（Principal components） strongly related to ENSO（El Nino southern oscillation） were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.

A preliminary experiment of determining the geopotential difference using two hydrogen atomic clocks and TWSTFT technique

General relativity theory(GRT)concludes that a precise clock ticks at different running rates if it is under the influence of different geopotentials.Therefore,by comparing the running rates of clocks at arbitrary two stations,the geopotential difference between them can be determined.In this study,with the help of two hydrogen atomic clocks(noted as H-masers),using the two-way satellite time and frequency transfer(TWSTFT)technique,we carried out experiments of the geopotential difference determination at the China Aerospace Science&Industry Corporation(CASIC),Beijing.Here the ensemble empirical mode decomposition(EEMD)method is adopted to remove periodic signals included in the original observations.Finally,the clock-comparison-determined geopotential difference in the experiments is determined.Results show that the difference between the geopotential difference determined by GRT and that determined by measuring tape is about 1316.1±931.0 m2s-2,which is equivalent to 134.3±95.0 m in height,and in consistence with the stability of the H-masers applied in the experiments(at the level of10-15/day).With the rapid improvement of atomic clocks’accuracy,the geopotential determination by accurate clocks is prospective,and it is promising to realize the unification of the world vertical height system(WVHS).

Atmospheric acceleration and Earth-expansion deceleration of the Earth rotation

Previous studies suggest that tidal friction gives rise to the secular deceleration of the Earth rotation by a quantity of about 2.25 ms/cy. Here we just consider additional contributions to the secular Earth rotation deceleration. Atmospheric solar semi-diurnal tide has a small amplitude and certain amount of phase lead. This periodic global air-mass excess distribution exerts a quasi-constant torque to accelerate the Earth＇s spin rotation. Using an updated atmospheric tide model, we re-estimate the amounts of this atmospheric acceleration torque and corresponding energy input, of which the associated change rate in LOD（length of day） is-0.1 ms/cy. In another aspect, evidences from space-geodesy and sea level rise observations suggest that Earth expands at a rate of 0.35 mm/yr in recent decades, which gives rise to the increase of LOD at rate of 1.0 ms/cy. Hence, if the previous estimate due to the tidal friction is correct, the secular Earth rotation deceleration due to tidal friction and Earth expansion should be 3.15 ms/cy.

Numerical solutions of rotational normal modes of a triaxial two-layered anelastic Earth

The Earth's rotational normal modes depend on Earth model used, including the layer structures,principal inertia moments of different layers and the compliances. This study focuses on providing numerical solution of the rotational normal modes of a triaxial two-layered anelastic Earth model without external forces but with considering the complex forms of compliances and the electromagnetic coupling between the core and mantle. Based on the present knowledge of the Chandler wobble(CW) and Free Core Nutation(FCN), we provide a set of complete compliances which could be used for reference in further investigations. There are eight rotational normal mode solutions, four of which might exist in nature. However, in reality only two of these four solutions correspond to the present motion status of the prograde CW and the retrograde FCN. On one hand, our numerical calculations show that the periods and quality factors(Qs) of CW and FCN are respectively 434.90 and 429.86 mean solar days(d) and 76.56 and 23988.47 under frequency-dependent assumption, and the triaxiality prolongs CW about 0.01 d and has hardly effect on FCN. On the other hand, we analyze the sensibility of compliances and electromagnetic coupling parameter on the periods and Qs of CW and FCN and find the sensitive parameters with respect to them.

Influencing factors on the accuracy of local geoid model

Different modification methods and software programs were developed to obtain accurate local geoid models in the past two decades.The quantitative effect of the main factors on the accuracy of local geoid modeling is still ambiguous and has not been clearly diagnosed yet.This study presents efforts to find the most influential factors on the accuracy of the local geoid model,as well as the amount of each factor’s effect quantitatively.The methodology covers extracting the quantitative characteristics of 16 articles regarding local geoid models of different countries.The Statistical Package of Social Sciences(SPSS)software formulated a strong multiple regression model of correlation coefficient r = 0.999 with a high significance coefficient of determination R^2 = 0.997 and adjusted R^2 = 0,98 for the required effective factors.Then,factor analysis is utilized to extract the dominant factors which include:accuracy of gravity data(40%),the density of gravity data(25%)(total gravity factors is 65%),the Digital Elevation Model(DEM)resolution(16%),the accuracy of GPS/leveling points(10%)and the area of the terrain of the country/state under the study(9%).These results of this study will assist in developing more accurate local geoid models.

Determination of the height of Mount Everest using the shallow layer method

Shallow layer method(SLM)based on the definition of the geoid can determine the gravity field inside the shallow layer.In this study,the orthometric height of Mount Everest(HME)is calculated based on SLM,in which the key is to construct the shallow layer model.The top and bottom boundaries of the shallow layer model are the natural surface of the Earth and the surface at a certain depth below the reference geoid,respectively.The model-combined strategies to determine the geoid undulation(N)based on SLM are applied to calculate the HME by two approaches:(1)direct calculation by combining N and geodetic height(h);(2)calculation by the segment summation approach(SSA)using the gravity field inside the shallow layer.On December 8,2020,the Chinese and Nepalese governments announced an authoritative value of 8848.86 m,which is referred to a geoid determined by the International Height Reference System(IHRS)(i.e.,the geopotential is 62636853.4 m^(2) s^(-2)).Here,our results(combined strategies(1)EGM2008 and CRUST1.0,(2)EGM2008 and CRUST2.0,(3)EIGEN-6 C4 and CRUST1.0,and(4)EIGEN-6 C4 and CRUST2.0)are referred to the geoid defined by WGS84(i.e.,the geopotential is 62636851.7 m^(2) s^(-2)).The differences between our results and the authoritative value(8848.86 m)are 0.448 m,-0.009 m,-0.295 m,and -0.741 m by the first approach,and 0.539 m,0.083 m,-0.214 m,and -0.647 m by the second approach.When the reference surface WGS84 geoid is converted to the IHRS geoid,the differences are 0.620 m,0.163 m,-0.123 m,and -0.569 m by the first approach,and0.711 m,0.225 m,-0.042 m,and -0.475 m by the second approach.

New estimation of triaxial three-layered Earth’s inertia tensor and solutions of Earth rotation normal modes

Until now, the calculation of the principal inertia moment of the triaxial three-layered Earth mainly adopts the scaling method. This method assumes that the corresponding principal inertia axes of the layers coincide each other, but this is not the case. In this paper, a rigorous tensor transformation rule is adopted to calculate the principal inertia moments(PIMs) of different layers. Appling the new estimated PIMs to the triaxial three-layered Earth rotation theory with considering various couplings, the numerical calculations show that the periods of the Chandler Wobble(CW), Free Core Nutation(FCN), Free Inner Core Nutation(FICN) and Inner Core Wobble(ICW) are respectively 433.0, 430.8, 943.9 and 2735.9 mean solar days, which are well comparable with the corresponding values accepted at present in geoscience community. Better estimates of the PIMs of different layers may provide better constrains on relevant physical parameters of the Earth’s interior.

Investigations of anomalous gravity signals prior to 71 large earthquakes based on a 4-years long superconducting gravimeter records

Using continuous 1-Hz sampling time-series recorded by a SC （superconducting gravimeter） at Hsinchu station, Taiwan of China, we investigate the anomalous gravity signals prior to 71 large earthquakes with moment magnitude larger than 7.0 （Mw7.0） occurred between 1 Jan 2008 and 31 Dec 2011. We firstly evaluate the noise level of the SC records at Hsinchu （HS） station in microseismic bands from 0.05 Hz to 0.1 Hz by computing the PSD （power spectral density） of seismically quiet days selected based on the RMS of records. Based on the analysis of the noise level and the spectral features of the seismically quiet SC records at I-IS station, we detect ACSs （anomalous gravity signals） prior to large earthquakes. We apply HHT （Hilbert-Huang transformation） to establish the TFEP （time-frequency-energy paradigms） and MS （marginal spectra） of the SC data before the large earthquakes, and the characteristics of TFEP and MS of the SCs data during the typhoon event are also analyzed. By comparing the spectral characteristics of the SCs data during seismically quiet period, three types of ACSs are found; and the occurrence rate of ACSs before 71 earthquakes is given in terms of the cases with different epicenter distance and different focal depth. The statistical results show that 56.3% of all the examined large earthquakes were preceded by AGSs; and if we constrain the epicenter distance to be smaller than 3500 km and focal depth less than 300 kin, 75.3% of the examined large earthquakes can be associated with the ACSs. Especially, we note that for all the large earthquakes occurred in the Eurasian plate in recent four years, the precursory AGSs can always be found in the SC data recorded at HS station. Our investigations suggest that the AGSs prior to large earthquakes may be related to focal depth, epicentre distance and location.

Decadal length-of-day and geomagnetic changes imply more complex Earth’s core motions

Since the 1950s,the length-of-day variations(DLOD)of the Earth’s rotation have received extensive attention and research in various fields,including geodynamics,geomagnetism,geodesy,seismology,geology,marine science,environmental science,and even biology and physics.Despite the abundance of related studies and notable advancements,the underlying mechanism behind the decadal changes in DLOD remains a persistent unresolved question.An essential aspect of investigating this issue lies in its potential to unveil the Earth’s core motions[1,2].Despite the presence of various hypothesized and constructed models about the Earth’s core motions,these models typically exhibit simplicity.