Along the Proterozoic stratigraphic sections of Jixian, Tianjin, the ??13C values of carbonates are mostly negative in the Changchengian (Changcheng System), varying approximately within a range of (0±1)‰ in the...Along the Proterozoic stratigraphic sections of Jixian, Tianjin, the ??13C values of carbonates are mostly negative in the Changchengian (Changcheng System), varying approximately within a range of (0±1)‰ in the Jixianian (Jixian System), and have commonly positive values of (2±2)‰ in the Qingbaikouan (Qingbaikou System). From Chuanlinggou Formation to Dahongyu Formation, i.e. from ca. 1700 Ma to 1600 Ma, the δ13C values of carbonates increase from about -3‰ to 0‰, but oscillate with large excursion in Dahongyu Formation. Two large excursions occur in the Jixianian, one in Yangzhuang Formation and the other in the third submember of Wumishan Formation overlaying. These integrated and continuous records of carbon isotope reflect secular variations of δ13C value in ancient seawater from ca. 1700 Ma to ca. 800 Ma. The increase and subsequent oscillation of seawater δ13C value occurring from the ages of ca. 1700 to ca. 1600 Ma and ＜1300 Ma may signify two correlative global tectonic events.展开更多
An investigation of the rock magnetic properties using stepwise isothermal remanence (IRM) acquisition, thermomagnetic analysis and temperature-dependent susceptibility history, identifies magnetite as the carrier of ...An investigation of the rock magnetic properties using stepwise isothermal remanence (IRM) acquisition, thermomagnetic analysis and temperature-dependent susceptibility history, identifies magnetite as the carrier of the main fraction of the remanence, associated with maghemite and hematite in Malan loess (L1), Holocene soil (S0) and last-glacial paleosol (S1). The presence of short-lived direction fluctuations indicates that no significant smoothing occurs in L1 when its remanence is locked, and thus L1 is capable of recording the geomagnetic secular variation (PSV), while the PSV has been severely smoothed or wiped out by pedogenic processes during S1 formation. It has been suggested that the Mono Lake and Laschamp excursions are two independent geomagnetic events based on this study.展开更多
Objective To analyze the change in Body Mass Index （BMI） distribution among Chinese children and adolescents for the development of more effective intervention for childhood obesity. Methods Data on the national stu...Objective To analyze the change in Body Mass Index （BMI） distribution among Chinese children and adolescents for the development of more effective intervention for childhood obesity. Methods Data on the national students＇ constitution and health survey between 1985 and 2010 was used for this study. Subjects were students aged 7-18 randomly selected from 30 provinces in China. BMI for-age curves were developed by LMS method, and the trend of BMI distribution was determined by comparing the upper BMI percentiles and analyzing the skew shift of distribution between 2985 and 2010. Results An overall positive swift trend of BMI between 1985 and 2010 was observed among the Chinese school-age children and adolescents. The average median of the BMI increased from 16.8 and 17.0 ks/m2 to 18.2 and 17.9 kg/m2 in 25 years, with increments 0.56 and 0.36 kg/m2 per decade for males and females, respectively. The more obvious increments were found at the high BMI. The total increments of BMI in this period were 4.03 and 2.20 kg/m2 at the 85th, 6.24 and 3.57 kg/m2 at the 95th, and 6.99 and 4.27 kg/m2 at the 97th percentiles, for males and females, respectively. Conclusion Obvious increments were observed at high BMI of the Chinese children and adolescents. More effective interventions should be taken for control and prevention of obesity and its health consequence for these subgroups. It is necessary to establish a risk-complex system consisting of the identification of BMI scope, the screen of the disease risk factors and the assessment of excessive adiposity.展开更多
The global long-term sea level trend is obtained from the analysis of tide gauge data and TOPEX/Poseidon data. The linear trend of global mean sea level is highly non-uniform spatially, with an average rate of 2.2 mmy...The global long-term sea level trend is obtained from the analysis of tide gauge data and TOPEX/Poseidon data. The linear trend of global mean sea level is highly non-uniform spatially, with an average rate of 2.2 mmyear^-1 in T/P sea-level rise from October 1992 to September 2002. Sea level change due to temperature variation （the thermosteric sea level） is discussed. The results are compared with TOPEX/Poseidon altimeter data in the same temporal span at different spatial scales. It is indicated that the thermal effect accounts for 86% and 73% of the observed seasonal variability in the northern and southern hemispheres, respectively. The TOPEX/Poseidon observed sea level lags behind the TSL by 2 months in the zonal band of 40%-60% in both the northern and southern hemispheres. Systematic differences of about 1-2 cm between TOPEX/Poseidon observations and thermosteric sea level data are obtained. The potential causes tbr these differences include water exchange among the atmosphere, land, and oceans, and some possible deviations in thermosteric contribution estimates and geophysical corrections to the TOPEX/Poseidon data.展开更多
Objective Research evidence shows a secular trend in Chinese physical growth in recent years.The aim of this study was to analyze and assess changes in stature of children and adolescents during the 25 years from 1985...Objective Research evidence shows a secular trend in Chinese physical growth in recent years.The aim of this study was to analyze and assess changes in stature of children and adolescents during the 25 years from 1985‐2010,using national data.Methods Data came from successive cycles of the Chinese National Survey on Students＇ Constitution and Health（CNSSCH）.Subjects were 7‐ to 18‐year‐old children and adolescents.Results An overall positive secular trend occurred in urban China during 1985‐2010.The overall average rates of increment were 2.4 and 1.7 cm/decade for boys and girls,respectively.Total increases in adult stature for boys and girls were 2.6 and 1.7 cm,yielding rates of 1.0 and 0.7 cm/decade,respectively.Cities with different socioeconomic levels had different characteristic trends.Mean stature increases in big cities were larger than those in moderate and small cities,and boys and girls in moderate and small cities showed greater potential for growth in stature.Conclusion An overall positive secular growth trend was associated with socioeconomic progress and differed with area socioeconomic levels.School policies and strategies should be developed based on increased stature,and should continue narrowing the inequity between different socioeconomic populations.展开更多
Objective To analyze and assess secular change in stature in rural children and adolescents in China from 1985 to 2010. Methods Data were obtained from the 6 rounds of the Chinese National Survey on Student＇s Constit...Objective To analyze and assess secular change in stature in rural children and adolescents in China from 1985 to 2010. Methods Data were obtained from the 6 rounds of the Chinese National Survey on Student＇s Constitution and Health. The subjects enrolled in the study were children and adolescents aged 7-18 years in rural areas of provincial capitals. Results An overall positive secular trend in stature occurred in rural areas of provincial capitals in China from 1985 to 2010. The overall average increase rates were 3.1 and 2.4 cm/decade for boys and girls, respectively. The total body height increases for grown up boys and girls were 3.6 and 2.3 cm and the increase rates were 1.4 and 0.9 cm/decade, respectively. There were differences in body height increase among eastern, central and western regions. The average body height of the children or adolescents in eastern region was highest, followed by central region and western region. The overall increase rates in central region were highest among the three regions. The difference between eastern/central region and western region was obvious. 〈br〉 Conclusion Positive secular trend in stature of children or adolescents has occurred in rural area of China, and rural boys and girls showed a great potential for continuous growth. More attention should be paid to the differences in children＇s body height between western region and eastern/central region.展开更多
Objective: The objective of this study was to characterize secular trends in the sex-specific, age-standardized incidence of lung cancer by histological type in Beijing, China, from 2000 to 2016 based on data from a p...Objective: The objective of this study was to characterize secular trends in the sex-specific, age-standardized incidence of lung cancer by histological type in Beijing, China, from 2000 to 2016 based on data from a populationbased cancer registry.Methods: Data on the incidence of cancer from 2000 to 2016 were obtained from the Beijing Cancer Registry.We examined trends in the sex-specific, age-standardized incidence of lung cancer by histological type using a Joinpoint regression model.Results: A total of 117,409 cases of lung cancer were diagnosed from 2000 to 2016. Overall, 73,062(62.23%)patients were males. The most common histological type among both sexes was adenocarcinoma; however, the proportion of adenocarcinoma differed significantly between males and females(45.36% vs. 77.14%, respectively,P<0.0001). The age-standardized incidence of total lung cancer increased from 2000 to 2010 with an annual percent change(APC) of 2.2% [95% confidence interval(95% CI), 1.5% to 2.9%] and stabilized thereafter. Among males, the incidence of total lung cancer peaked in 2008 and then decreased slightly, with an APC of-1.1%(95%CI,-2.1% to-0.1%). Among females, the incidence increased continuously during the study period, with an APC of 1.4%(95% CI, 0.9% to 1.9%). The incidence of squamous cell carcinoma decreased significantly in recent years among both sexes, with APCs of-2.6%(95% CI,-4.5% to-0.6%) from 2007 to 2016 for males and-5.4%(95%CI,-7.2% to-3.6%) from 2004 to 2016 for females. In contrast, the incidence of adenocarcinoma increased continuously throughout the study period, by APCs of 4.0%(95% CI, 2.6% to 5.4%) for males and 6.2%(95% CI,4.8% to 7.6%) for females. The incidence of small cell carcinoma peaked in 2007 and stabilized thereafter among males, whereas it peaked in 2012 and then decreased with an APC of-14.7%(95% CI,-25.3% to-2.6%) among females. The incidence of large cell carcinoma and other specified malignant neoplasm did not change much,whereas the incidence of unspecified type decreased among both 展开更多
Due to global warming, the general circulation, underlying surfaces characteristics, and geophysical and meteorological elements all show evident secular trends. This paper points out that when calculating the correla...Due to global warming, the general circulation, underlying surfaces characteristics, and geophysical and meteorological elements all show evident secular trends. This paper points out that when calculating the correlation of two variables containing their own obvious secular trends, the interannual correlation characteristics between the two variables may be distorted （overestimated or underestimated）. Numerical experiments in this paper show that if two variables have opposite secular trends, the correlation coefficient between the two variables is reduced （the positive correlation is underestimated, or the negative correlation is overestimated）; and if the two variables have the same sign of secular trends, the correlation coefficient between the two variables is increased （the positive correlation is overestimated, or the negative correlation is underestimated）. Numerical experiments also suggest that the effect of secular trends on the interannual correlation of the two variables is interchangeable, that is to say, as long as the values of the two trends are not changed, the two variables interchange their positions, and the effect of the secular trends on the interannual correlation coefficient of the two variables remains the same. If the two variables have the same-（opposite-） sign trends, the effect of secular trends on the interannal correlation coefficient is more （less） distinctive. A meteorological example is given.展开更多
We have developed a structure of dynamic knowledge for non-inertial systems, the so-called Theory of Dynamic Interactions (TDI) as a part of non-inertial dynamic knowledge, which incorporates a causal demonstration of...We have developed a structure of dynamic knowledge for non-inertial systems, the so-called Theory of Dynamic Interactions (TDI) as a part of non-inertial dynamic knowledge, which incorporates a causal demonstration of phenomena accelerated by rotation, which would complement Classical Mechanics. We believe that the TDI mathematical model that we propose is of great conceptual importance. In addition, we think that it is not only necessary to understand the dynamics of rotating bodies, but also to understand the dynamics of the cosmos, with bodies that orbit and with constantly recurring movements, which make possible systems that have been in dynamic equilibrium for centuries and are not in a process of unlimited expansion. We even believe that this new dynamic theory allows us a better understanding of our universe, and the matter from which it is made.展开更多
Analysis of the International Geomagnetic Reference Field (IGRF) 1900-2000 showsthat the Earth’s main magnetic field has changed dramatically during the 20th century: its dipole moment has decreased by 6.5% since 190...Analysis of the International Geomagnetic Reference Field (IGRF) 1900-2000 showsthat the Earth’s main magnetic field has changed dramatically during the 20th century: its dipole moment has decreased by 6.5% since 1900, the strengths of its quadrupole and octupole have increased by 95% and 74%, respectively, four major planetary-scale magnetic anomalies on the Earth’s surface have enhanced by 21%-56%, and the magnetic center has shifted 200 km towards the Pacific Ocean. These time-variation features are similar to the behavior before a geomagnetic polarity reversal.展开更多
Low background gamma spectrometry was used to measure the radionuclides activity of <sup>238</sup>U, <sup>232</sup>Th, and <sup>235</sup>U series as well as <sup>40</sup>...Low background gamma spectrometry was used to measure the radionuclides activity of <sup>238</sup>U, <sup>232</sup>Th, and <sup>235</sup>U series as well as <sup>40</sup>K and <sup>137</sup>Cs in a sediment sample. The goal of the study was to measure the <sup>238</sup>U (63.3 keV peak of <sup>234</sup>Th;1001 keV peak of <sup>234m</sup>Pa) and <sup>235</sup>U (143.76 keV, 163.33 keV, and 205.31 keV peaks) activity by low background gamma spectrometry in sediment sample. <sup>235</sup>U activity in environmental samples is difficult to accurately measure by gamma spectrometry due to its low abundance in nature and low gamma line intensities at 143.76 keV, 163.33 keV, and 205.31 keV. We have shown that by using low background gamma spectrometry, it is possible to accurately measure the <sup>235</sup>U activity in sediment samples. The <sup>235</sup>U activity was measured without using the major peak of 185.7 keV (I<sub>γ</sub> = 57.2%) which requires interference correction from 186.21 keV of <sup>226</sup>Ra. <sup>226</sup>Ra activity was determined by measuring <sup>222</sup>Rn daughters (<sup>214</sup>Pb and <sup>214</sup>Bi). The precision and accuracy of the gamma activity measurement in the sediment sample were verified by using the HPGe detectors with Certified Reference Material (CRM) Irish Sea Sediment (IAEA-385). The results obtained for the 63.33 keV energy line of <sup>234</sup>Th are compared with the 1001 keV energy line of <sup>234m</sup>Pa. The values of <sup>238</sup>U and <sup>235</sup>U activities, as well as <sup>40</sup>K, <sup>137</sup>Cs, and <sup>226</sup>Ra, agreed with the certificate values of CRM. The results show that the <sup>238</sup>U is in equilibrium with its daughters (<sup>234</sup>Th, <sup>234m</sup>Pa, and <sup>210</sup>Pb). <sup>232</sup>Th is also in equilibrium with its daughters (<sup>228</sup>Ra, <sup>212</sup>Pb, <sup>212</sup>Bi and <sup>208</sup>Tl). <sup>235</sup>U/<sup>238</sup>U activity ratio of 0.046 ± 0.007 in the sediment is constant in nature but fluctuates 展开更多
Shale and greywacke compositions from the Archean to Phanerozoic record a secular change in the siliciclastic material that comprises much of Earth＇s continental margins, past and present. This study explores the met...Shale and greywacke compositions from the Archean to Phanerozoic record a secular change in the siliciclastic material that comprises much of Earth＇s continental margins, past and present. This study explores the metamorphic consequence of these compositional changes, by comparing phase equilibrium models constructed for average Archean, Proterozoic, and Phanerozoic shale and greywacke compositions equilibrated along two Barrovian-type geotherms： 1330℃/GPa（A） and 800 ℃/GPa（B）. Our models show that Archean siliciclastic rocks can retain up to 4 vol.% water at middle to lower crustal conditions, nearly twice that of Proterozoic and Phanerozoic compositions. The increased ferromagnesium content of Archean siliciclastic rocks stabilizes chlorite to higher temperatures and results in a biotite-rich assemblage at solidus temperatures. Accordingly, water-absent biotite dehydration melting is predicted to play a greater role in the generation of melt in the metamorphism of Archean aged units,and water-absent muscovite dehydration melting is of increasing importance through the Proterozoic and Phanerozoic. This secular variation in predicted mineral assemblages demonstrates the care with which metamorphic facies diagrams should be applied to Archean compositions. Moreover, secular changes in the composition of shale and greywacke is reflected in the evolution of anatectic melt towards an increasingly less viscous, Ca-rich, and Mg-poor monzogranite.展开更多
Objective To describe secular trends on physical growth of children in China during the year of 1985‐2005 and to analyze the urban‐suburban‐rural difference and its change. Methods The measurements of height, weigh...Objective To describe secular trends on physical growth of children in China during the year of 1985‐2005 and to analyze the urban‐suburban‐rural difference and its change. Methods The measurements of height, weight and chest circumference obtained from two serial national cross‐sectional surveys for children aged 0 to 7 years in China were used to analyze the secular trends, and the growth differences among urban, suburban and rural children were compared. Results The average weight and height for both boys and girls from urban, suburban and rural areas have significantly increased in most age groups during the past 20 years; The average chest circumference increased slightly, ranging from 0.0 to 2.0 cm. From 1985 to 2005, the urban‐suburban difference in height had become smaller, and that in weight showed similar trend for children under 3 years old but became larger after 3 years old; the suburban‐rural difference both in height and weight became larger after 6 months old. The increment per decade in height was the greatest in the suburban group while the greatest increment in weight was the urban group. Conclusion Positive secular trends were observed among urban, suburban and rural areas in Chinese children under 7 years old during the 1980s and the 2000s, reflecting a rapid socio‐economic development in China.展开更多
Objective To explore the influence of secular trends in body height and weight on the prevalence of overweight and obesity among Chinese children and adolescents. Methods The data were obtained from five cross-section...Objective To explore the influence of secular trends in body height and weight on the prevalence of overweight and obesity among Chinese children and adolescents. Methods The data were obtained from five cross-sectional Chinese National Surveys on Students＇ Constitution and Health. Overweight/obesity was defined as BMI-for-age Z-score of per the Wold Health Organization （WHO） reference values. Body height and weight for each sex and age were standardized to those reported in 1985 （standardized height＂ SHY, standardized weight： SWY） and for each sex and year at age 7 （standardized height： SHA; standardized weight： SWA） using the Z-score method. Results The prevalence of overweight/obesity in Chinese children was 20.2% among boys and 10.7% among girls in 2010 and increased continuously from 1985 to 2010. Among boys and girls of normal weight, SHY and SHA were significantly greater than SWY and SWA, respectively （P 〈 0.001）. Among boys and girls with overweight/obesity, SHY was significantly lower than SWY （P 〈 0.001）, and showed an obvious decreasing trend after age 12. SHA was lower than SWA among overweight boys aged 7-8 years and girls aged 7-9 years. SHY/SHW and SHA/SWA among normal-weight groups were greater than among overweight and obese groups （P 〈 0.001）. Conclusion The continuous increase in the prevalence of overweight/obesity among Chinese children may be related to a rapid increase in body weight before age 9 and lack of secular increase in body height after age 12.展开更多
Background:Few studies on spatial patterns or secular trends in human leishmanias have been conducted in Morocco.This study aimed to examine spatial patterns and trends associated with the human leishmaniasis incidenc...Background:Few studies on spatial patterns or secular trends in human leishmanias have been conducted in Morocco.This study aimed to examine spatial patterns and trends associated with the human leishmaniasis incidence rate(HLIR)at the province/prefecture level between 2003 and 2013 in Morocco.Methods:Only the available published country data on the HLIR between 2003 and 2013,from the open access files of the Ministry of Health,were used.Secular trends were examined using Kendall’s rank correlation.An exploratory spatial data analysis was also conducted to examine the spatial autocorrelation(Global Moran’s I and local indicator of spatial association[LISA]),and spatial diffusion at the province/prefecture level.The influence of various covariates(poverty rate,vulnerability rate,population density,and urbanization)on the HLIR was tested via spatial regression(ordinary least squares regression).Results:At the country level,no secular variation was observed.Poisson annual incidence rate estimates were 13 per 100000 population(95%CI=12.9–13.1)for cutaneous leishmaniasis(CL)and 0.4 per 100000 population(95%CI=0.4–0.5)for visceral leishmaniasis(VL).The available data on HLIR were based on combined CL and VL cases,however,as the CL cases totally outnumbered the VL ones,HLIR may be considered as CL incidence rate.At the provincial level,a secular increase in the incidence rate was observed in Al Hoceima(P=0.008),Taounate(P=0.04),Larache(P=0.002),Tétouan(P=0.0003),Khenifra(P=0.008),Meknes(P=0.03),and El Kelaa(P=0.0007),whereas a secular decrease was observed only in the Chichaoua province(P=0.006).Even though increased or decreased rate was evident in these provinces,none of them showed clustering of leishmaniasis incidence.Significant spatial clusters of high leishmaniasis incidence were located in the northeastern part of Morocco,while spatial clusters of low leishmaniasis incidence were seen in some northwestern and southern parts of Morocco;there was spatial randomness in the remaining parts of the country.Si展开更多
The Coupled Model Inter-comparison Project Phase 5 （CMIP5） contains a group of state-of-the-art climate models and represents the highest level of climate simulation thus far. However, these models significantly ove...The Coupled Model Inter-comparison Project Phase 5 （CMIP5） contains a group of state-of-the-art climate models and represents the highest level of climate simulation thus far. However, these models significantly overestimated global mean surface temperature （GMST） during 2006-2014. Based on the ensemble empirical mode decomposition （EEMD） method, the long term change of the observed GMST time series of HadCRUT4 records during 1850-2014 was analyzed, then the simulated GMST by 33 CMIP5 climate models was assessed. The possible reason that climate models failed to project the recent global warming hiatus was revealed. Results show that during 1850-2014 the GMST on a centennial timescale rose with fluctuation, dominated by the secular trend and the multi-decadal variability （MDV）. The secular trend was relatively steady beginning in the early 20th century, with an average warming rate of 0.0883℃/decade over the last 50 years. While the MDV （with a -65-year cycle） showed 2.5 multi-decadal waves during 1850-2014, which deepened and steepened with time, the alarming warming over the last quarter of the 20th century was a result of the concurrence of the secular wanning trend and the warming phase of the MDV, both of which accounted one third of the temperature increase during 1975-1998. Recently the slowdown of global warming emerged as the MDV approached its third peak, leading to a reduction in the warming rate. A comparative analysis between the GMST time series derived from HadCRUT4 records and 33 CMIP5 model outputs reveals that the GMSTs during the historical simulation period of 1850-2005 can be reproduced well by models, especially on the accelerated global warming over the last quarter of 20th century. However, the projected GMSTs and their linear trends during 2006-2014 under the RCP4.5 scenario were significantly higher than observed. This is because the CMIP5 models confused the MDV with secular trend underlying the GMST time series, which results in a fast secular trend and an imprope展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 49973008, 40172015) the Chinese Academy of Sciences (Grant No. KZCX2-116).
文摘Along the Proterozoic stratigraphic sections of Jixian, Tianjin, the ??13C values of carbonates are mostly negative in the Changchengian (Changcheng System), varying approximately within a range of (0±1)‰ in the Jixianian (Jixian System), and have commonly positive values of (2±2)‰ in the Qingbaikouan (Qingbaikou System). From Chuanlinggou Formation to Dahongyu Formation, i.e. from ca. 1700 Ma to 1600 Ma, the δ13C values of carbonates increase from about -3‰ to 0‰, but oscillate with large excursion in Dahongyu Formation. Two large excursions occur in the Jixianian, one in Yangzhuang Formation and the other in the third submember of Wumishan Formation overlaying. These integrated and continuous records of carbon isotope reflect secular variations of δ13C value in ancient seawater from ca. 1700 Ma to ca. 800 Ma. The increase and subsequent oscillation of seawater δ13C value occurring from the ages of ca. 1700 to ca. 1600 Ma and ＜1300 Ma may signify two correlative global tectonic events.
文摘An investigation of the rock magnetic properties using stepwise isothermal remanence (IRM) acquisition, thermomagnetic analysis and temperature-dependent susceptibility history, identifies magnetite as the carrier of the main fraction of the remanence, associated with maghemite and hematite in Malan loess (L1), Holocene soil (S0) and last-glacial paleosol (S1). The presence of short-lived direction fluctuations indicates that no significant smoothing occurs in L1 when its remanence is locked, and thus L1 is capable of recording the geomagnetic secular variation (PSV), while the PSV has been severely smoothed or wiped out by pedogenic processes during S1 formation. It has been suggested that the Mono Lake and Laschamp excursions are two independent geomagnetic events based on this study.
基金supported by National Natural Science Foundation of China(30972495,81001249)
文摘Objective To analyze the change in Body Mass Index （BMI） distribution among Chinese children and adolescents for the development of more effective intervention for childhood obesity. Methods Data on the national students＇ constitution and health survey between 1985 and 2010 was used for this study. Subjects were students aged 7-18 randomly selected from 30 provinces in China. BMI for-age curves were developed by LMS method, and the trend of BMI distribution was determined by comparing the upper BMI percentiles and analyzing the skew shift of distribution between 2985 and 2010. Results An overall positive swift trend of BMI between 1985 and 2010 was observed among the Chinese school-age children and adolescents. The average median of the BMI increased from 16.8 and 17.0 ks/m2 to 18.2 and 17.9 kg/m2 in 25 years, with increments 0.56 and 0.36 kg/m2 per decade for males and females, respectively. The more obvious increments were found at the high BMI. The total increments of BMI in this period were 4.03 and 2.20 kg/m2 at the 85th, 6.24 and 3.57 kg/m2 at the 95th, and 6.99 and 4.27 kg/m2 at the 97th percentiles, for males and females, respectively. Conclusion Obvious increments were observed at high BMI of the Chinese children and adolescents. More effective interventions should be taken for control and prevention of obesity and its health consequence for these subgroups. It is necessary to establish a risk-complex system consisting of the identification of BMI scope, the screen of the disease risk factors and the assessment of excessive adiposity.
基金supported by the NSFC projects (Nos. 40376005, 40676013, 40506006 and 40676015)the SRFDP project (No. 20060423014)+1 种基金NCET-04-0646 Key Scientific Research Program (No. 2007CB411807)National Key Technology R&D Program (No. 2007BAC- 03A06-06)
文摘The global long-term sea level trend is obtained from the analysis of tide gauge data and TOPEX/Poseidon data. The linear trend of global mean sea level is highly non-uniform spatially, with an average rate of 2.2 mmyear^-1 in T/P sea-level rise from October 1992 to September 2002. Sea level change due to temperature variation （the thermosteric sea level） is discussed. The results are compared with TOPEX/Poseidon altimeter data in the same temporal span at different spatial scales. It is indicated that the thermal effect accounts for 86% and 73% of the observed seasonal variability in the northern and southern hemispheres, respectively. The TOPEX/Poseidon observed sea level lags behind the TSL by 2 months in the zonal band of 40%-60% in both the northern and southern hemispheres. Systematic differences of about 1-2 cm between TOPEX/Poseidon observations and thermosteric sea level data are obtained. The potential causes tbr these differences include water exchange among the atmosphere, land, and oceans, and some possible deviations in thermosteric contribution estimates and geophysical corrections to the TOPEX/Poseidon data.
基金supported by the National Natural Science Foundation of China(30972495,81001249)
文摘Objective Research evidence shows a secular trend in Chinese physical growth in recent years.The aim of this study was to analyze and assess changes in stature of children and adolescents during the 25 years from 1985‐2010,using national data.Methods Data came from successive cycles of the Chinese National Survey on Students＇ Constitution and Health（CNSSCH）.Subjects were 7‐ to 18‐year‐old children and adolescents.Results An overall positive secular trend occurred in urban China during 1985‐2010.The overall average rates of increment were 2.4 and 1.7 cm/decade for boys and girls,respectively.Total increases in adult stature for boys and girls were 2.6 and 1.7 cm,yielding rates of 1.0 and 0.7 cm/decade,respectively.Cities with different socioeconomic levels had different characteristic trends.Mean stature increases in big cities were larger than those in moderate and small cities,and boys and girls in moderate and small cities showed greater potential for growth in stature.Conclusion An overall positive secular growth trend was associated with socioeconomic progress and differed with area socioeconomic levels.School policies and strategies should be developed based on increased stature,and should continue narrowing the inequity between different socioeconomic populations.
基金supported by the National Natural Science Foundation of China(81001249,30972495)
文摘Objective To analyze and assess secular change in stature in rural children and adolescents in China from 1985 to 2010. Methods Data were obtained from the 6 rounds of the Chinese National Survey on Student＇s Constitution and Health. The subjects enrolled in the study were children and adolescents aged 7-18 years in rural areas of provincial capitals. Results An overall positive secular trend in stature occurred in rural areas of provincial capitals in China from 1985 to 2010. The overall average increase rates were 3.1 and 2.4 cm/decade for boys and girls, respectively. The total body height increases for grown up boys and girls were 3.6 and 2.3 cm and the increase rates were 1.4 and 0.9 cm/decade, respectively. There were differences in body height increase among eastern, central and western regions. The average body height of the children or adolescents in eastern region was highest, followed by central region and western region. The overall increase rates in central region were highest among the three regions. The difference between eastern/central region and western region was obvious. 〈br〉 Conclusion Positive secular trend in stature of children or adolescents has occurred in rural area of China, and rural boys and girls showed a great potential for continuous growth. More attention should be paid to the differences in children＇s body height between western region and eastern/central region.
基金supported by the Beijing Young Talent Program (No. 20160000 21469G189)
文摘Objective: The objective of this study was to characterize secular trends in the sex-specific, age-standardized incidence of lung cancer by histological type in Beijing, China, from 2000 to 2016 based on data from a populationbased cancer registry.Methods: Data on the incidence of cancer from 2000 to 2016 were obtained from the Beijing Cancer Registry.We examined trends in the sex-specific, age-standardized incidence of lung cancer by histological type using a Joinpoint regression model.Results: A total of 117,409 cases of lung cancer were diagnosed from 2000 to 2016. Overall, 73,062(62.23%)patients were males. The most common histological type among both sexes was adenocarcinoma; however, the proportion of adenocarcinoma differed significantly between males and females(45.36% vs. 77.14%, respectively,P<0.0001). The age-standardized incidence of total lung cancer increased from 2000 to 2010 with an annual percent change(APC) of 2.2% [95% confidence interval(95% CI), 1.5% to 2.9%] and stabilized thereafter. Among males, the incidence of total lung cancer peaked in 2008 and then decreased slightly, with an APC of-1.1%(95%CI,-2.1% to-0.1%). Among females, the incidence increased continuously during the study period, with an APC of 1.4%(95% CI, 0.9% to 1.9%). The incidence of squamous cell carcinoma decreased significantly in recent years among both sexes, with APCs of-2.6%(95% CI,-4.5% to-0.6%) from 2007 to 2016 for males and-5.4%(95%CI,-7.2% to-3.6%) from 2004 to 2016 for females. In contrast, the incidence of adenocarcinoma increased continuously throughout the study period, by APCs of 4.0%(95% CI, 2.6% to 5.4%) for males and 6.2%(95% CI,4.8% to 7.6%) for females. The incidence of small cell carcinoma peaked in 2007 and stabilized thereafter among males, whereas it peaked in 2012 and then decreased with an APC of-14.7%(95% CI,-25.3% to-2.6%) among females. The incidence of large cell carcinoma and other specified malignant neoplasm did not change much,whereas the incidence of unspecified type decreased among both
文摘Due to global warming, the general circulation, underlying surfaces characteristics, and geophysical and meteorological elements all show evident secular trends. This paper points out that when calculating the correlation of two variables containing their own obvious secular trends, the interannual correlation characteristics between the two variables may be distorted （overestimated or underestimated）. Numerical experiments in this paper show that if two variables have opposite secular trends, the correlation coefficient between the two variables is reduced （the positive correlation is underestimated, or the negative correlation is overestimated）; and if the two variables have the same sign of secular trends, the correlation coefficient between the two variables is increased （the positive correlation is overestimated, or the negative correlation is underestimated）. Numerical experiments also suggest that the effect of secular trends on the interannual correlation of the two variables is interchangeable, that is to say, as long as the values of the two trends are not changed, the two variables interchange their positions, and the effect of the secular trends on the interannual correlation coefficient of the two variables remains the same. If the two variables have the same-（opposite-） sign trends, the effect of secular trends on the interannal correlation coefficient is more （less） distinctive. A meteorological example is given.
文摘We have developed a structure of dynamic knowledge for non-inertial systems, the so-called Theory of Dynamic Interactions (TDI) as a part of non-inertial dynamic knowledge, which incorporates a causal demonstration of phenomena accelerated by rotation, which would complement Classical Mechanics. We believe that the TDI mathematical model that we propose is of great conceptual importance. In addition, we think that it is not only necessary to understand the dynamics of rotating bodies, but also to understand the dynamics of the cosmos, with bodies that orbit and with constantly recurring movements, which make possible systems that have been in dynamic equilibrium for centuries and are not in a process of unlimited expansion. We even believe that this new dynamic theory allows us a better understanding of our universe, and the matter from which it is made.
文摘Analysis of the International Geomagnetic Reference Field (IGRF) 1900-2000 showsthat the Earth’s main magnetic field has changed dramatically during the 20th century: its dipole moment has decreased by 6.5% since 1900, the strengths of its quadrupole and octupole have increased by 95% and 74%, respectively, four major planetary-scale magnetic anomalies on the Earth’s surface have enhanced by 21%-56%, and the magnetic center has shifted 200 km towards the Pacific Ocean. These time-variation features are similar to the behavior before a geomagnetic polarity reversal.
文摘Low background gamma spectrometry was used to measure the radionuclides activity of <sup>238</sup>U, <sup>232</sup>Th, and <sup>235</sup>U series as well as <sup>40</sup>K and <sup>137</sup>Cs in a sediment sample. The goal of the study was to measure the <sup>238</sup>U (63.3 keV peak of <sup>234</sup>Th;1001 keV peak of <sup>234m</sup>Pa) and <sup>235</sup>U (143.76 keV, 163.33 keV, and 205.31 keV peaks) activity by low background gamma spectrometry in sediment sample. <sup>235</sup>U activity in environmental samples is difficult to accurately measure by gamma spectrometry due to its low abundance in nature and low gamma line intensities at 143.76 keV, 163.33 keV, and 205.31 keV. We have shown that by using low background gamma spectrometry, it is possible to accurately measure the <sup>235</sup>U activity in sediment samples. The <sup>235</sup>U activity was measured without using the major peak of 185.7 keV (I<sub>γ</sub> = 57.2%) which requires interference correction from 186.21 keV of <sup>226</sup>Ra. <sup>226</sup>Ra activity was determined by measuring <sup>222</sup>Rn daughters (<sup>214</sup>Pb and <sup>214</sup>Bi). The precision and accuracy of the gamma activity measurement in the sediment sample were verified by using the HPGe detectors with Certified Reference Material (CRM) Irish Sea Sediment (IAEA-385). The results obtained for the 63.33 keV energy line of <sup>234</sup>Th are compared with the 1001 keV energy line of <sup>234m</sup>Pa. The values of <sup>238</sup>U and <sup>235</sup>U activities, as well as <sup>40</sup>K, <sup>137</sup>Cs, and <sup>226</sup>Ra, agreed with the certificate values of CRM. The results show that the <sup>238</sup>U is in equilibrium with its daughters (<sup>234</sup>Th, <sup>234m</sup>Pa, and <sup>210</sup>Pb). <sup>232</sup>Th is also in equilibrium with its daughters (<sup>228</sup>Ra, <sup>212</sup>Pb, <sup>212</sup>Bi and <sup>208</sup>Tl). <sup>235</sup>U/<sup>238</sup>U activity ratio of 0.046 ± 0.007 in the sediment is constant in nature but fluctuates
文摘Shale and greywacke compositions from the Archean to Phanerozoic record a secular change in the siliciclastic material that comprises much of Earth＇s continental margins, past and present. This study explores the metamorphic consequence of these compositional changes, by comparing phase equilibrium models constructed for average Archean, Proterozoic, and Phanerozoic shale and greywacke compositions equilibrated along two Barrovian-type geotherms： 1330℃/GPa（A） and 800 ℃/GPa（B）. Our models show that Archean siliciclastic rocks can retain up to 4 vol.% water at middle to lower crustal conditions, nearly twice that of Proterozoic and Phanerozoic compositions. The increased ferromagnesium content of Archean siliciclastic rocks stabilizes chlorite to higher temperatures and results in a biotite-rich assemblage at solidus temperatures. Accordingly, water-absent biotite dehydration melting is predicted to play a greater role in the generation of melt in the metamorphism of Archean aged units,and water-absent muscovite dehydration melting is of increasing importance through the Proterozoic and Phanerozoic. This secular variation in predicted mineral assemblages demonstrates the care with which metamorphic facies diagrams should be applied to Archean compositions. Moreover, secular changes in the composition of shale and greywacke is reflected in the evolution of anatectic melt towards an increasingly less viscous, Ca-rich, and Mg-poor monzogranite.
基金supported by the Ministry of Health of the People's Republic of China(No.2005‐41)
文摘Objective To describe secular trends on physical growth of children in China during the year of 1985‐2005 and to analyze the urban‐suburban‐rural difference and its change. Methods The measurements of height, weight and chest circumference obtained from two serial national cross‐sectional surveys for children aged 0 to 7 years in China were used to analyze the secular trends, and the growth differences among urban, suburban and rural children were compared. Results The average weight and height for both boys and girls from urban, suburban and rural areas have significantly increased in most age groups during the past 20 years; The average chest circumference increased slightly, ranging from 0.0 to 2.0 cm. From 1985 to 2005, the urban‐suburban difference in height had become smaller, and that in weight showed similar trend for children under 3 years old but became larger after 3 years old; the suburban‐rural difference both in height and weight became larger after 6 months old. The increment per decade in height was the greatest in the suburban group while the greatest increment in weight was the urban group. Conclusion Positive secular trends were observed among urban, suburban and rural areas in Chinese children under 7 years old during the 1980s and the 2000s, reflecting a rapid socio‐economic development in China.
基金supported by the National Natural Science Foundation of China(81502823)
文摘Objective To explore the influence of secular trends in body height and weight on the prevalence of overweight and obesity among Chinese children and adolescents. Methods The data were obtained from five cross-sectional Chinese National Surveys on Students＇ Constitution and Health. Overweight/obesity was defined as BMI-for-age Z-score of per the Wold Health Organization （WHO） reference values. Body height and weight for each sex and age were standardized to those reported in 1985 （standardized height＂ SHY, standardized weight： SWY） and for each sex and year at age 7 （standardized height： SHA; standardized weight： SWA） using the Z-score method. Results The prevalence of overweight/obesity in Chinese children was 20.2% among boys and 10.7% among girls in 2010 and increased continuously from 1985 to 2010. Among boys and girls of normal weight, SHY and SHA were significantly greater than SWY and SWA, respectively （P 〈 0.001）. Among boys and girls with overweight/obesity, SHY was significantly lower than SWY （P 〈 0.001）, and showed an obvious decreasing trend after age 12. SHA was lower than SWA among overweight boys aged 7-8 years and girls aged 7-9 years. SHY/SHW and SHA/SWA among normal-weight groups were greater than among overweight and obese groups （P 〈 0.001）. Conclusion The continuous increase in the prevalence of overweight/obesity among Chinese children may be related to a rapid increase in body weight before age 9 and lack of secular increase in body height after age 12.
文摘Background:Few studies on spatial patterns or secular trends in human leishmanias have been conducted in Morocco.This study aimed to examine spatial patterns and trends associated with the human leishmaniasis incidence rate(HLIR)at the province/prefecture level between 2003 and 2013 in Morocco.Methods:Only the available published country data on the HLIR between 2003 and 2013,from the open access files of the Ministry of Health,were used.Secular trends were examined using Kendall’s rank correlation.An exploratory spatial data analysis was also conducted to examine the spatial autocorrelation(Global Moran’s I and local indicator of spatial association[LISA]),and spatial diffusion at the province/prefecture level.The influence of various covariates(poverty rate,vulnerability rate,population density,and urbanization)on the HLIR was tested via spatial regression(ordinary least squares regression).Results:At the country level,no secular variation was observed.Poisson annual incidence rate estimates were 13 per 100000 population(95%CI=12.9–13.1)for cutaneous leishmaniasis(CL)and 0.4 per 100000 population(95%CI=0.4–0.5)for visceral leishmaniasis(VL).The available data on HLIR were based on combined CL and VL cases,however,as the CL cases totally outnumbered the VL ones,HLIR may be considered as CL incidence rate.At the provincial level,a secular increase in the incidence rate was observed in Al Hoceima(P=0.008),Taounate(P=0.04),Larache(P=0.002),Tétouan(P=0.0003),Khenifra(P=0.008),Meknes(P=0.03),and El Kelaa(P=0.0007),whereas a secular decrease was observed only in the Chichaoua province(P=0.006).Even though increased or decreased rate was evident in these provinces,none of them showed clustering of leishmaniasis incidence.Significant spatial clusters of high leishmaniasis incidence were located in the northeastern part of Morocco,while spatial clusters of low leishmaniasis incidence were seen in some northwestern and southern parts of Morocco;there was spatial randomness in the remaining parts of the country.Si
基金supported by the National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers(Grant No.U1406404)the Transparent Ocean Project (Grant No.2015ASKJ01)the corresponding author is also supported by Ao-Shan Talent Program
文摘The Coupled Model Inter-comparison Project Phase 5 （CMIP5） contains a group of state-of-the-art climate models and represents the highest level of climate simulation thus far. However, these models significantly overestimated global mean surface temperature （GMST） during 2006-2014. Based on the ensemble empirical mode decomposition （EEMD） method, the long term change of the observed GMST time series of HadCRUT4 records during 1850-2014 was analyzed, then the simulated GMST by 33 CMIP5 climate models was assessed. The possible reason that climate models failed to project the recent global warming hiatus was revealed. Results show that during 1850-2014 the GMST on a centennial timescale rose with fluctuation, dominated by the secular trend and the multi-decadal variability （MDV）. The secular trend was relatively steady beginning in the early 20th century, with an average warming rate of 0.0883℃/decade over the last 50 years. While the MDV （with a -65-year cycle） showed 2.5 multi-decadal waves during 1850-2014, which deepened and steepened with time, the alarming warming over the last quarter of the 20th century was a result of the concurrence of the secular wanning trend and the warming phase of the MDV, both of which accounted one third of the temperature increase during 1975-1998. Recently the slowdown of global warming emerged as the MDV approached its third peak, leading to a reduction in the warming rate. A comparative analysis between the GMST time series derived from HadCRUT4 records and 33 CMIP5 model outputs reveals that the GMSTs during the historical simulation period of 1850-2005 can be reproduced well by models, especially on the accelerated global warming over the last quarter of 20th century. However, the projected GMSTs and their linear trends during 2006-2014 under the RCP4.5 scenario were significantly higher than observed. This is because the CMIP5 models confused the MDV with secular trend underlying the GMST time series, which results in a fast secular trend and an imprope
