Since the 1975 M_(S)7.3 Haicheng earthquake,spatio-temporal variations in the gravity field have attracted much attention as potential earthquake precursors.Recent technical advances in terrestrial gravity observation...Since the 1975 M_(S)7.3 Haicheng earthquake,spatio-temporal variations in the gravity field have attracted much attention as potential earthquake precursors.Recent technical advances in terrestrial gravity observation,along with the construction of a high-precision mobile gravity network covering Chinese mainland,have positioned temporal gravity variations(GVs)as an important tool for clarifying the signal characteristics and dynamic mechanisms of crustal sources.Reportedly,crustal mass transfer,which is affected by stress state and structural environment,alters the characteristics of the regional gravity field,thus serving as an indicator for locations of moderate to strong earthquakes and a seismology-independent predictor for regions at risk for strong earthquakes.Therefore,quantitatively tracking time-varying gravity is of paramount importance to enhance the effectiveness of earthquake prediction.In this study,we divided the areas effectively covered by the terrestrial mobile gravity network in the Sichuan-Yunnan region into small grids based on the latest observational data(since 2018)from the network.Next,we calculated the 1-and 3-year GVs and gravity gradient indicators(amplitude of analytic signal,AAS;total horizontal derivative,THD;and amplitude of vertical gradient,AVG)to quantitatively characterize variations in regional time-varying gravity field.Next,we assessed the effectiveness of gravity field variations in predicting earthquakes in the Sichuan-Yunnan region using Molchan diagrams constructed for gravity signals of 13 earthquakes(M≥5.0;occurred between 2021 and 2024)within the terrestrial mobile gravity network.The results reveal a certain correspondence between gravity field variations and the locations of moderate and strong earthquakes in the Sichuan-Yunnan region.Furthermore,the 3-year AAS and AVG outperform the 3-year THD in predicting subsequent seismic events.Notably,the AAS and AVG showed large probability gains prior to the M_(S)6.8 Luding earthquake,indicating their potential for earthquake prediction.展开更多
Most fish exhibit remarkable morphological diversity,which is often influenced by genetic variation and ecological pressures.Consequently,these are the outcomes of organisms’responses to their environment.Meanwhile,m...Most fish exhibit remarkable morphological diversity,which is often influenced by genetic variation and ecological pressures.Consequently,these are the outcomes of organisms’responses to their environment.Meanwhile,modern morphometrics can quantify shape variation within species of the same group.This study aims to determine the body shape variation of Glossogobius giuris from Lake Mainit,Agusan Del Norte,Philippines.60 adult,uniform-sized fish samples were collected and subjected to standardized laboratory procedures.Further,the samples were digitized for 16 homologous landmark points and loaded into Symmetry Asymmetry Geometric Data(SAGE)Software.Across the tested factors—individuals,sides,and individual x sides—result shows that shape variations among individuals were highly significant(F=2.1045,p<0.0001),along with among males(F=3.2711,p<0.0001).Females exhibited higher Fluctuating Asymmetry(FA)(F=18.99,p<0.0001)compared to males(F=7.0964,p<0.0001).It suggests morphological shape differences across the sexes,and the shape variation observed could be a response to environmental perturbations.Shape variations were associated with swimming,food hunting,and predator defense.Moreover,Principal Component Analysis(PCA)demonstrates higher scores of FA in females(81.96%)than in males(74.76%).It was noticed that females had a high fluctuating asymmetry.It might be due to various physiological and ecological pressures compared to males.The observed levels of directional and fluctuating asymmetry in males and females,respectively,may indicate sex-linked morphological and developmental processes,which are important to consider in ecological or evolutionary contexts.Thus,utilizing geometric morphometrics can depict subtle differences across the same populations.展开更多
Copy number variations(CNVs), which can affect the role of long non-coding RNAs(lncRNAs), are important genetic changes seen in some malignant tumors. We analyzed lncRNAs with CNV to explore the relationship between l...Copy number variations(CNVs), which can affect the role of long non-coding RNAs(lncRNAs), are important genetic changes seen in some malignant tumors. We analyzed lncRNAs with CNV to explore the relationship between lncRNAs and prognosis in bladder cancer(BLCA). Messenger RNA(mRNA) expression levels, DNA methylation, and DNA copy number data of 408 BLCA patients were subjected to integrative bioinformatics analysis. Cluster analysis was performed to obtain different subtypes and differently expressed lncRNAs and coding genes. Weighted gene co-expression network analysis(WGCNA) was performed to identify the co-expression gene and lncRNA modules. CNV-associated lncRNA data and their influence on cancer prognosis were assessed with Kaplan-Meier survival curve. Multi-omics integration analysis revealed five prognostic lncRNAs with CNV, namely NR2 F1-AS1, LINC01138, THUMPD3-AS1, LOC101928489, and TMEM147-AS1, and a risk-score signature related to overall survival in BLCA was identified. Moreover, validated results in another independent Gene Expression Omnibus(GEO) dataset, GSE31684, were consistent with these results. Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis revealed that the mitogen-activated protein kinase(MAPK) signaling pathway, focal adhesion pathway, and Janus kinase-signal transducers and activators of transcription(JAK-STAT) signaling pathway were enriched in a high-risk score pattern, suggesting that imbalance in these pathways is closely related to tumor development. We revealed the prognosis-related lncRNAs by analyzing the expression profiles of lncRNAs and CNVs, which can be used as prognostic biomarkers for BLCA.展开更多
Transcription, post-transcriptional modification, translation, post-translational modification, DNA replication, and signaling interaction of intra- and extra- cellular components are the relevant mechanisms in gene r...Transcription, post-transcriptional modification, translation, post-translational modification, DNA replication, and signaling interaction of intra- and extra- cellular components are the relevant mechanisms in gene regulation. Transcription is one of the most important mechanisms in the control of gene expression. Further, post-transcriptional modifications play a crucial role after transcription which determine whether the transcribed gene is coding or non-coding RNA (ncRNAs). Genome-wide analysis of RNAs provides information about the coding RNAs, whereas the status of ncRNAs are still at large and must be discussed in detail as variations in the ncRNAs can lead to different phenotypes. In this short article, we discuss the role of genetic variation in ncRNA genes and how this variation may play a crucial role in ncRNA biogenesis that eventually leads to phenotypic variation and thus speciation.展开更多
We investigated the seasonal and spatial ozone variations in China by using three-year surface ozone observation data from the six Chinese Global Atmosphere Watch(GAW)stations and tropospheric column ozone data from s...We investigated the seasonal and spatial ozone variations in China by using three-year surface ozone observation data from the six Chinese Global Atmosphere Watch(GAW)stations and tropospheric column ozone data from satellite retrieval over the period2010–2012. It is shown that the seasonal ozone variations at these GAW stations are rather different, particularly between the western and eastern locations. Compared with western China, eastern China has lower background ozone levels. However, the Asian summer monsoon(ASM) can transport photochemical pollutants from the southern to the northern areas in eastern China, leading to a northward gradual enhancement of background ozone levels at the eastern GAW stations. Over China, the tropospheric column ozone densities peak during spring and summer in the areas that are directly and/or indirectly affected by the ASM, and the peak time lags from the south to the north in eastern China. We also investigated the regional representativeness of seasonal variations of ozone at the six Chinese GAW stations using the yearly maximum tropospheric column month as indicator.The results show that the seasonal variation characteristics of ozone revealed by the Chinese GAW stations are typical, with each station having a considerable large surrounding area with the ozone maximum occurring at the same month. Ozone variations at the GAW stations are influenced by many complex factors and their regional representativeness needs to be investigated further in a broader sense.展开更多
The agricultural and land policies in China are always focused on protecting its food supply and security because of the country＇s large population and improved diets. The crop production guide ＇Take Grain as the Ke...The agricultural and land policies in China are always focused on protecting its food supply and security because of the country＇s large population and improved diets. The crop production guide ＇Take Grain as the Key Link prompted peasants to plant grain on most of the agricultural land, leading to the majority of fertilizer being used in grain crops for many years in China. This situation has changed dramatically in recent years. Based on data pertaining to provincial crops sown area and fertilizer use per unit area in 1998 and 2008, the temporal and spatial variations of China＇s fertilizer consumption by crops were analyzed at the provincial level, and the results are presented here. （1） Fertilizer consumption in China grew strongly in the last decade, while the growth was mainly attributable to the increase of fertilizer consumption by horticultural crops. The fertilizer consumption of grain crops dropped from 71.0% in 1998 to 57.8% in 2008. Thus, it is concluded that the emphasis of fertilizer consumption is shifting toward horticultural crops. （2） There were marked differences in the growth rates of fertilizer consumption from the regional point of view. The national average growth rate of fertilizer consumption was 31.9% during 1998-2008. The western and northeastern parts of the country came close to the national average, while the eastern part was lower, with an average of 13.0%, and central China was much higher （50.8%）. The increase of fertilizer consumption in central and west China was higher than the other zones, which already accounted for 77.9% of the national total. Thus, it is concluded that the consumption emphasis of chemical fertilizer shifts toward the central and western regions. （3） The decline of fertilizer consumption by grain crops was largely due to the decrease in sown area compared with the increase by vegetable crops attributable to the enlarging sown area; the increase by orchard crops was affected by both expanding the sown area and fertilizer use per unit area.展开更多
As one of the areas with numerous lakes on the Tibetan Plateau, the Hoh Xil region plays an extremely important role in the fragile plateau eco-environment. Based on topographic maps in the 1970s and Landsat TM/ETM＋ ...As one of the areas with numerous lakes on the Tibetan Plateau, the Hoh Xil region plays an extremely important role in the fragile plateau eco-environment. Based on topographic maps in the 1970s and Landsat TM/ETM＋ remote sensing images iin the 1990s and the period from 2000 to 2011, the data of 83 lakes with an area above 10 km2 each were obtained by digitization method and artificial visual interpretation technology, and the causes for lake variations were also analyzed. Some conclusions can be drawn as follows. （1） From the 1970s to 2011, the lakes in the Hoh Xil region firstly shrank and then expanded, in particular, the area of lakes generally decreased during the 1970s-1990s. Then the lakes expanded from the 1990s to 2000 and the area was slightly higher than that in the 1970s. The area of lakes dramatically increased after 2000. （2） From 2000 to 2011, the lakes with different area ranks in the Hoh Xil region showed an overall expansion trend. Meanwhile, some regional differences were also discovered. Most of the lakes expanded and were widely distributed in the northern, central and western parts of the region. Some lakes were merged together or overflowed due to their rapid expansion. A small number of lakes with the trend of area decrease or strong fluctuation were scattered in the central and southern parts of the study area. And their variations were related to their own supply conditions or hydraulic connection with the downstream lakes or rivers. （3） The increase in precipitation was the dominant factor resulting in the expansion of lakes in the Hoh Xil region. The secondary factor was the increase in meltwater from glaciers and frozen soil due to climate warming.展开更多
Analysis of spatial-temporal variations of desert vegetation under the background of climate changes can provide references for ecological restoration in arid and semi-arid areas. In this study, we used the Global Inv...Analysis of spatial-temporal variations of desert vegetation under the background of climate changes can provide references for ecological restoration in arid and semi-arid areas. In this study, we used the Global Inventory Modeling and Mapping Studies （GIMMS） NDVI data from 1982 to 2006 and Moderate Resolution Imaging Spectroradiometer （MODIS） NDVI data from 2000 to 2013 to reveal the dynamics of desert vegetation in Hexi region of Northwest China over the past three decades. We also used the annual temperature and precipitation data acquired from the Chinese meteorological stations to analyze the response of desert vegetation to climatic variations. The average value of NDVImax （the maximum NDVI during the growing season） for desert vegetation in Hexi region increased at the rate of 0.65x10-3/a （P〈0.05） from 1982 to 2013, and the significant increases of NDVImax mainly appeared in the typical desert vegetation areas. Vegetation was significantly improved in the lower reaches of Shule and Shiyang river basins, and the weighted mean center of desert vegetation mainly shifted toward the lower reaches of the two basins. Almost 95.32% of the total desert vegetation area showed positive correlation between NDVImax and annual precipitation, indicating that precipitation is the key factor for desert vegetation growth in the entire study area. Moreover, the areas with non-significant positive correlation between NDVImax and annual precipitation mainly located in the lower reaches of Shiyang and Shule river basins, this may be due to human activities. Only 7.64% of the desert vegetation showed significant positive correlation between NDVImax and annual precipitation in the Shule River Basin （an extremely arid area）, indicating that precipitation is not the most important factor for vegetation growth in this basin, and further studies are needed to investigate the mechanism for this phenomenon.展开更多
Runoff at the three time scales （non-flooding season, flooding season and annual period） was simulated and tested from 1958 to 2005 at Tangnaihai （Yellow River Source Region： YeSR）, Zhimenda （Yangtze River Sourc...Runoff at the three time scales （non-flooding season, flooding season and annual period） was simulated and tested from 1958 to 2005 at Tangnaihai （Yellow River Source Region： YeSR）, Zhimenda （Yangtze River Source Region： YaSR） and Changdu （Lancang River Source Region： LcSR） by hydrological modeling, trend detection and comparative analysis. Also, future runoff variations from 2010 to 2039 at the three outlets were analyzed in A1B and B1 scenarios of CSIRO and NCAR climate model and the impact of climate change was tested. The results showed that the annual and non-flooding season runoff decreased significantly in YeSR, which decreased the water discharge to the midstream and down- stream of the Yellow River, and intensified the water shortage in the Yellow River Basin, but the other two regions were not statistically significant in the last 48 years. Compared with the runoff in baseline （1990s）, the runoff in YeSR would decrease in the following 30 years （2010-2039）, especially in the non-flooding season. Thus the water shortage in the mid- stream and downstream of the Yellow River Basin would be serious continuously. The runoff in YaSR would increase, especially in the flooding season, thus the flood control situation would be severe. The runoff in LcSR would also be greater than the current runoff, and the annual and flooding season runoff would not change significantly, while the runoff variation in the non-flooding season is uncertain. It would increase significantly in the B1 scenario of CSIRO model but decrease significantly in B1 scenario of NCAR model. Furlhermore, the most sensitive region to climate change is YaSR, followed by YeSR and LcSR.展开更多
Based on a monthly dataset of precipitation time series （1961-2010） from 12 me- teorological stations across the Three-River Headwater Region （THRHR） of Qinghai Province China, the spatio-temporal variation and ab...Based on a monthly dataset of precipitation time series （1961-2010） from 12 me- teorological stations across the Three-River Headwater Region （THRHR） of Qinghai Province China, the spatio-temporal variation and abrupt change analysis of precipitation were exam- ined by using moving average, linear regression, spline interpolation, the Mann-Kendall test and so on. Major conclusions were as follows. （1） The long-term annual and seasonal pre- cipitation in the study area indicated an increasing trend with some oscillations during 1961-2010; however, the summer precipitation in the Lantsang （Lancang） River Headwater Region （LARHR）, and the autumn precipitation in the Yangtze River Headwater Region （YERHR） of the THRHR decreased in the same period. （2） The amount of annual precipita- tion in the THRHR and its three sub-headwater regions was greater in the 1980s and 2000s. The springs were fairly wet after the 1970s, while the summers were relatively wet in the 1960s, 1980s and 2000s. In addition, the amount of precipitation in the autumn was greater in the 1970s and 1980s, but it was relatively less for the winter precipitation, except in the 1990s （3） The normal values of spring, summer, winter and annual precipitation in the THRHR and its three sub-headwater regions all increased, but the normal value of summer precipitation in the LARHR had a negative trend and the normal value of winter precipitation declined in general. （4） The spring and winter precipitation increased in most of the THRHR. The summer autumn and annual precipitation increased mainly in the marginal area of the west and north and decreased in the regions of Yushu, Zaduo, Jiuzhi and Banma. （5） The spring and winter precipitation in the THRHR and its three sub-headwater regions showed an abrupt change, except for the spring precipitation in the YARHR. The abrupt changes of spring precipitation were mainly in the late 1980s and early 1990s, while the abrupt changes of winter precipita- tion were primary in the mid- to late 1970s. This research would be helpful for further under- standing the trends and periodicity of precipitation and for watershed-based water resource management in the THRHR.展开更多
In this study, a monthly dataset of temperature time series （1961-2010） from 12 meteorological stations across the Three-River Headwater Region of Qinghai Province （THRHR） was used to analyze the climate change. T...In this study, a monthly dataset of temperature time series （1961-2010） from 12 meteorological stations across the Three-River Headwater Region of Qinghai Province （THRHR） was used to analyze the climate change. The temperature variation and abrupt change analysis were examined by using moving average, linear regression, Spline interpolation, Mann-Kendall test and so on. Some important conclusions were obtained from this research, which mainly contained four aspects as follows. （1） There were several cold and warm fluctuations for the annual and seasonal average temperature in the THRHR and its three sub-headwater regions, but the temperature in these regions all had an obviously rising trend at the statistical significance level, especially after 2001. The spring, summer, autumn and annual average temperature increased evidently after the 1990s, and the winter average temperature exhibited an obvious upward trend after entering the 21st century. Except the standard value of spring temperature, the annual and seasonal temperature standard value in the THRHR and its three sub-headwater regions increased gradually, and the upward trend for the standard value of winter average temperature indicated significantly. （2） The tendency rate of annual average temperature in the THRHR was 0.36℃ 10a^-1, while the tendency rates in the Yellow River Headwater Region （YERHR）, Lancangjiang River Headwater Region （LARHR） and Yangtze River Headwater Region （YARHR） were 0.37℃ 10a^-1, 0.37℃ 10a^-1 and 0.34℃10a^-1 respectively. The temperature increased significantly in the south of Yushu County and the north of Nangqian County. The rising trends of temperature in winter and autumn were higher than the upward trends in spring and summer. （3） The abrupt changes of annual, summer, autumn and winter average temperature were found in the THRHR, LARHR and YARHR, and were detected for the summer and autumn average temperature in the YERHR. The abrupt changes of annual and summer average temperatures were mainly in the late 1990s, while the abrupt changes of autumn and winter average temperatures appeared primarily in the early 1990s and the early 21st century respectively. （4） With the global warming, the diversities of altitude and underlying surface in different parts of the Tibetan Plateau were possibly the main reasons for the high increasing rate of temperature in the THRHR.展开更多
In this work, the National Center for Environmental Prediction/ National Center for Atmospheic Research (NCEP/ NCAR) global daily–mean reanalysis data are used to diagnose the features of the local circulation variat...In this work, the National Center for Environmental Prediction/ National Center for Atmospheic Research (NCEP/ NCAR) global daily–mean reanalysis data are used to diagnose the features of the local circulation variation during the South China Sea (SCS) monsoon in 1998. It is found that by taking the appearance of southwest wind in lower layers and east wind in upper layers as the sign of the monsoon onset, the SCS monsoon starts on May 25 in 1998, which is later than that in normal years. The formation of the SCS monsoon is not a simple propagation of southwest monsoon in the north—south direction, but a process in which the southwest wind starts first over the north of the SCS, withdraws southward, and then propagates from south to north again. During this process, both meteorological elements and circulation fields change significantly. The outbreak of the SCS monsoon is the result of the seasonal variation of the height in lower and upper layers. The air rounding the Tibetan Plateau might be one of the dynamic reasons that make the summer monsoon start over the SCS at first. At the different stages of the monsoon, the vertical circulations as well as the lower and the upper layer divergence fields undergo evident temporal and regional changes. The SCS monsoon has the 60–day, 20–30–day and 8–15–day low frequency oscillations (LFOs), and dominant scale changes at the different stages of monsoon. The monsoon onset is related to the superimposition of the amplitudes of LFOs with different scales. Key words SCS monsoon - Circulation variation - Regional climate - LFO Sponsored by the National Key Project of Fundamental Research SCSMEX展开更多
Pneumoconiosis is a restrictive lung disease mostly caused by occupational exposure to dust,including silica dust,asbestos,and other fibers.Inhalable particles smaller than 10μm can enter the bronchioles,injure lung ...Pneumoconiosis is a restrictive lung disease mostly caused by occupational exposure to dust,including silica dust,asbestos,and other fibers.Inhalable particles smaller than 10μm can enter the bronchioles,injure lung cells,and induce lung fibrosis.This hard-to-cure disease places a substantial burden on patients and society[1].展开更多
The concentrations of heavy metals Ba, Pb, Cu, Zn and Co in snow pit collected in September, 2005 from the accumulation area of the East Rongbuk Glacier （6523 m a.s.l.）, which lies on the northern slope of Mt. Qomol...The concentrations of heavy metals Ba, Pb, Cu, Zn and Co in snow pit collected in September, 2005 from the accumulation area of the East Rongbuk Glacier （6523 m a.s.l.）, which lies on the northern slope of Mt. Qomolangma, were determined by inductively coupled plasma mass spectrometry （ICP-MS）. Concentrations （pg/ml） of heavy metals are Ba2-227, Co2.8-15.7, Cu10-120, Zn29-4948 and Pb14-142, respectively. The 5180 was determined by MAT-252. The time period of the snow pit spans from autumn 2005 to summer 2004. Seasonal variations of the concentrations and δ^18O are observed, of which Pb, Cu, Zn and Co are much lower in summer monsoon season than that in non summer monsoon season, suggesting that different sources of heavy metals contributed to the site. EFc （crustal enrichment factors） is Co3.6, Cu27, Pb33 and Zn180, respectively. Higher EFo values of Pb, Cu and Zn suggest that Pb, Cu especially Zn are mainly contributed by anthropogenic sources.展开更多
Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced b...Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced by meteorological variables, it is necessary to investigate the extent to which different meteorological variables affect the potential evaporation. The aim of this study was to explore the variation trends of different meteorological variables, and their impacts on the potential evaporation. This study selected the Hailar Meteorological Station of the Hailar region, which is situated in a cold, semi-arid, and sub-humid region, as a case study site. Based on observed daily meteorological data from 1951 to 2009, the potential evaporation was calculated with the Penman formula, and the variations of meteorological variables were investigated with the nonparametric Mann-Kendall test. The correlation between the potential evaporation and each meteorological variable at annual and seasonal scales was also analyzed. The results show that the annual and seasonal potential evaporation and air temperature present increasing trends, whereas the wind speed, sunshine duration, and relative humidity present decreasing trends. Among the meteorological variables, the air temperature and relative humidity are the key factors that affect potential evaporation at different time scales, and the impacts of other meteorological variables on the potential evaporation are not significant and vary with time scales.展开更多
Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application ...Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.展开更多
The wind field plays a decisive role in haze generation and dissipation processes over the Beijing- Tianjin-Hebei （BTH） region. Although geographically the BTH region is under the influence of the East Asian winter ...The wind field plays a decisive role in haze generation and dissipation processes over the Beijing- Tianjin-Hebei （BTH） region. Although geographically the BTH region is under the influence of the East Asian winter monsoon （EAWM）, this study finds that common indices of the EAWM cannot adequately describe the actual wind speed changes in the BTH region.Thus, observational data are used to analyze the interannual variations of the winter wind field over the BTH region. The results show that the average winter wind speed is 2.0 m s-1, with a slight rate of decline of 0.01 m s-1 yr-1. In most cases, strong-wind years correspond to negative sea surface temperature （SST） anomalies over the tropical Pacific, whereas weak-wind years correspond to positive SST anomalies. Moreover, correlation and composite analyses show that the interannual variability is affected by multiple factors, including the following： （1） the pressure gradient in the high and middle latitudes of the Northern Hemisphere, as in strong-wind years the pressure gradient helps cold air move from high latitudes to middle latitudes; （2） the skin temperature in Eurasia, as low skin temperature in Eurasia in strong-wind years is conducive to the accumulation of cold air; and （3） the SST of the tropical Pacific east of the Philippines, as in strong-wind years the high temperature of this area affects the BTH region through anticyclonic activity and associated tropical circulation systems.展开更多
BACKGROUND Incidence and severity variations of inflammatory bowel disease(IBD)have been reported from Western populations between continents and regions of the same countries.However,no data were available from other...BACKGROUND Incidence and severity variations of inflammatory bowel disease(IBD)have been reported from Western populations between continents and regions of the same countries.However,no data were available from other countries.AIM To investigate the regional differences in the IBD profiles of pediatric patients from the Kingdom of Saudi Arabia.METHODS Data from a national multicenter IBD study were used.The incidence,time trend,and clinical presentation of Crohn’s disease(CD)and ulcerative colitis(UC)in the Central region(CR),Western region(WR),and Eastern region(ER)were analyzed and compared.Statistical analysis included Poisson regression analysis for incidence variation and Chi-square test for demographic and clinical parameters.A P<0.05 was considered significant.RESULTS The prevalence of positive family history was lower in children with CD from the ER than the CR or the WR.Consanguinity rate was higher in children with CD and UC from the CR and the ER,respectively.The incidences and time trends of CD and UC were not significantly different between regions.In the ER,a significantly higher percentage of children with CD presented with abdominal pain(P<0.001),blood in stools(P=0.048),stricturing or penetrating disease(P=0.029),higher erythrocyte sedimentation rate(P<0.001),higher C-reactive protein(P<0.001),higher anemia(P=0.017),and lower albumin level(P=0.014).For children with UC from the ER,a significantly higher percentage presented with anemia(P=0.006)and a lower percentage with pancolitis(P<0.001).CONCLUSION The most important finding is the identification of significantly more severe presentation of CD in the ER of the Kingdom of Saudi Arabia.Prospective studies are needed to explain such variations.展开更多
The West Development Policy being implemented in China is causing significant land use and land cover （LULC） changes in West China. With the up-to-date satellite database of the Global Land Cover Characteristics Dat...The West Development Policy being implemented in China is causing significant land use and land cover （LULC） changes in West China. With the up-to-date satellite database of the Global Land Cover Characteristics Database （GLCCD） that characterizes the lower boundary conditions, the regional climate model RIEMS-TEA is used to simulate possible impacts of the significant LULC variation. The model was run for five continuous three-month periods from 1 June to 1 September of 1993, 1994, 1995, 1996, and 1997, and the results of the five groups are examined by means of a student t-test to identify the statistical significance of regional climate variation. The main results are： （1） The regional climate is affected by the LULC variation because the equilibrium of water and heat transfer in the air-vegetation interface is changed. （2） The integrated impact of the LULC variation on regional climate is not only limited to West China where the LULC varies, but also to some areas in the model domain where the LULC does not vary at all. （3） The East Asian monsoon system and its vertical structure are adjusted by the large scale LULC variation in western China, where the consequences are the enhancement of the westward water vapor transfer from the east oast and the relevant increase of wet-hydrostatic energy in the middle-upper atmospheric layers. （4） The ecological engineering in West China affects significantly the regional climate in Northwest China, North China and the middle-lower reaches of the Yangtze River; there are obvious effects in South, Northeast, and Southwest China, but minor effects in Tibet.展开更多
A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotrans...A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotranspiration(PET) was predicted using a modified Penman-Monteith(P-M) model. The region's ratio of precipitation to evapotranspiration was calculated as the humidity index(HI). The data obtained was used to analyze climatic responses to land cover conversions from the perspectives of evapotranspiration and humidity variations. The results show that, from 1997 to 2009, the average annual PET increased in the early years and decreased later. In terms of overall spatial distribution, a significant reciprocal relationship appeared between annual PET and annual HI. In 1997,the annual PET was higher in the lower reaches than in the upper reaches of the TGRR, but the areas with high PET shifted substantially westward by 2003. The annual PET continued to increase in 2006, but the areas with high PET shrank by 2009. In contrast, the annual HI showed varying degrees of localized spatial variability. Over the three periods, the dominantforms of land cover conversions occurred from evergreen cover to seasonal green cover, from seasonal green cover to evergreen cover, and from seasonal green cover to seasonally inundated areas, respectively. These accounted for 48.0%, 38.4%, and 23.8% of the total areas of converted land covers in the three periods, respectively. During the period between 1997 and 2003, the main forms of land cover conversions resulted in both positive and negative growths in the average annual PET, while all of them pushed down the average annual HI. From 2003 to 2006, the reservoir region experienced neither a decrease in the annual PET nor an increase in the annual HI. The period between 2006 and 2009 saw a consistent downward trend in the annual PET and a consistent upward trend in the annual HI.展开更多
基金funded by the National Key R&D Program of China(Nos.2023YFE0101800 and 2023YFC 3007305)National Natural Science Foundation of China(Nos.42004069 and 42204093)Special Fund of the Institute of Geophysics,China Earthquake Administration(No.DQJB24X24).
文摘Since the 1975 M_(S)7.3 Haicheng earthquake,spatio-temporal variations in the gravity field have attracted much attention as potential earthquake precursors.Recent technical advances in terrestrial gravity observation,along with the construction of a high-precision mobile gravity network covering Chinese mainland,have positioned temporal gravity variations(GVs)as an important tool for clarifying the signal characteristics and dynamic mechanisms of crustal sources.Reportedly,crustal mass transfer,which is affected by stress state and structural environment,alters the characteristics of the regional gravity field,thus serving as an indicator for locations of moderate to strong earthquakes and a seismology-independent predictor for regions at risk for strong earthquakes.Therefore,quantitatively tracking time-varying gravity is of paramount importance to enhance the effectiveness of earthquake prediction.In this study,we divided the areas effectively covered by the terrestrial mobile gravity network in the Sichuan-Yunnan region into small grids based on the latest observational data(since 2018)from the network.Next,we calculated the 1-and 3-year GVs and gravity gradient indicators(amplitude of analytic signal,AAS;total horizontal derivative,THD;and amplitude of vertical gradient,AVG)to quantitatively characterize variations in regional time-varying gravity field.Next,we assessed the effectiveness of gravity field variations in predicting earthquakes in the Sichuan-Yunnan region using Molchan diagrams constructed for gravity signals of 13 earthquakes(M≥5.0;occurred between 2021 and 2024)within the terrestrial mobile gravity network.The results reveal a certain correspondence between gravity field variations and the locations of moderate and strong earthquakes in the Sichuan-Yunnan region.Furthermore,the 3-year AAS and AVG outperform the 3-year THD in predicting subsequent seismic events.Notably,the AAS and AVG showed large probability gains prior to the M_(S)6.8 Luding earthquake,indicating their potential for earthquake prediction.
文摘Most fish exhibit remarkable morphological diversity,which is often influenced by genetic variation and ecological pressures.Consequently,these are the outcomes of organisms’responses to their environment.Meanwhile,modern morphometrics can quantify shape variation within species of the same group.This study aims to determine the body shape variation of Glossogobius giuris from Lake Mainit,Agusan Del Norte,Philippines.60 adult,uniform-sized fish samples were collected and subjected to standardized laboratory procedures.Further,the samples were digitized for 16 homologous landmark points and loaded into Symmetry Asymmetry Geometric Data(SAGE)Software.Across the tested factors—individuals,sides,and individual x sides—result shows that shape variations among individuals were highly significant(F=2.1045,p<0.0001),along with among males(F=3.2711,p<0.0001).Females exhibited higher Fluctuating Asymmetry(FA)(F=18.99,p<0.0001)compared to males(F=7.0964,p<0.0001).It suggests morphological shape differences across the sexes,and the shape variation observed could be a response to environmental perturbations.Shape variations were associated with swimming,food hunting,and predator defense.Moreover,Principal Component Analysis(PCA)demonstrates higher scores of FA in females(81.96%)than in males(74.76%).It was noticed that females had a high fluctuating asymmetry.It might be due to various physiological and ecological pressures compared to males.The observed levels of directional and fluctuating asymmetry in males and females,respectively,may indicate sex-linked morphological and developmental processes,which are important to consider in ecological or evolutionary contexts.Thus,utilizing geometric morphometrics can depict subtle differences across the same populations.
基金supported by the Natural Science Foundation of Guangdong Province (No. 2017A030313898)the Guangzhou Science and Technology Plan Projects (No. 201707010113), China。
文摘Copy number variations(CNVs), which can affect the role of long non-coding RNAs(lncRNAs), are important genetic changes seen in some malignant tumors. We analyzed lncRNAs with CNV to explore the relationship between lncRNAs and prognosis in bladder cancer(BLCA). Messenger RNA(mRNA) expression levels, DNA methylation, and DNA copy number data of 408 BLCA patients were subjected to integrative bioinformatics analysis. Cluster analysis was performed to obtain different subtypes and differently expressed lncRNAs and coding genes. Weighted gene co-expression network analysis(WGCNA) was performed to identify the co-expression gene and lncRNA modules. CNV-associated lncRNA data and their influence on cancer prognosis were assessed with Kaplan-Meier survival curve. Multi-omics integration analysis revealed five prognostic lncRNAs with CNV, namely NR2 F1-AS1, LINC01138, THUMPD3-AS1, LOC101928489, and TMEM147-AS1, and a risk-score signature related to overall survival in BLCA was identified. Moreover, validated results in another independent Gene Expression Omnibus(GEO) dataset, GSE31684, were consistent with these results. Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis revealed that the mitogen-activated protein kinase(MAPK) signaling pathway, focal adhesion pathway, and Janus kinase-signal transducers and activators of transcription(JAK-STAT) signaling pathway were enriched in a high-risk score pattern, suggesting that imbalance in these pathways is closely related to tumor development. We revealed the prognosis-related lncRNAs by analyzing the expression profiles of lncRNAs and CNVs, which can be used as prognostic biomarkers for BLCA.
文摘Transcription, post-transcriptional modification, translation, post-translational modification, DNA replication, and signaling interaction of intra- and extra- cellular components are the relevant mechanisms in gene regulation. Transcription is one of the most important mechanisms in the control of gene expression. Further, post-transcriptional modifications play a crucial role after transcription which determine whether the transcribed gene is coding or non-coding RNA (ncRNAs). Genome-wide analysis of RNAs provides information about the coding RNAs, whereas the status of ncRNAs are still at large and must be discussed in detail as variations in the ncRNAs can lead to different phenotypes. In this short article, we discuss the role of genetic variation in ncRNA genes and how this variation may play a crucial role in ncRNA biogenesis that eventually leads to phenotypic variation and thus speciation.
基金supported by the LAC/CMA(No.2017B02)the National Natural Science Foundation of China(No.41330422)the Special Fund for Meteorological Research in the Public Interest(No.GYHY201206015)
文摘We investigated the seasonal and spatial ozone variations in China by using three-year surface ozone observation data from the six Chinese Global Atmosphere Watch(GAW)stations and tropospheric column ozone data from satellite retrieval over the period2010–2012. It is shown that the seasonal ozone variations at these GAW stations are rather different, particularly between the western and eastern locations. Compared with western China, eastern China has lower background ozone levels. However, the Asian summer monsoon(ASM) can transport photochemical pollutants from the southern to the northern areas in eastern China, leading to a northward gradual enhancement of background ozone levels at the eastern GAW stations. Over China, the tropospheric column ozone densities peak during spring and summer in the areas that are directly and/or indirectly affected by the ASM, and the peak time lags from the south to the north in eastern China. We also investigated the regional representativeness of seasonal variations of ozone at the six Chinese GAW stations using the yearly maximum tropospheric column month as indicator.The results show that the seasonal variation characteristics of ozone revealed by the Chinese GAW stations are typical, with each station having a considerable large surrounding area with the ozone maximum occurring at the same month. Ozone variations at the GAW stations are influenced by many complex factors and their regional representativeness needs to be investigated further in a broader sense.
基金Foundation： National Natural Science Foundation of China, No. 40971062 National Basic Research Program of China, No.2010CB950902+1 种基金 National Natural Science Foundation of China, No.41101085 No.41171079
文摘The agricultural and land policies in China are always focused on protecting its food supply and security because of the country＇s large population and improved diets. The crop production guide ＇Take Grain as the Key Link prompted peasants to plant grain on most of the agricultural land, leading to the majority of fertilizer being used in grain crops for many years in China. This situation has changed dramatically in recent years. Based on data pertaining to provincial crops sown area and fertilizer use per unit area in 1998 and 2008, the temporal and spatial variations of China＇s fertilizer consumption by crops were analyzed at the provincial level, and the results are presented here. （1） Fertilizer consumption in China grew strongly in the last decade, while the growth was mainly attributable to the increase of fertilizer consumption by horticultural crops. The fertilizer consumption of grain crops dropped from 71.0% in 1998 to 57.8% in 2008. Thus, it is concluded that the emphasis of fertilizer consumption is shifting toward horticultural crops. （2） There were marked differences in the growth rates of fertilizer consumption from the regional point of view. The national average growth rate of fertilizer consumption was 31.9% during 1998-2008. The western and northeastern parts of the country came close to the national average, while the eastern part was lower, with an average of 13.0%, and central China was much higher （50.8%）. The increase of fertilizer consumption in central and west China was higher than the other zones, which already accounted for 77.9% of the national total. Thus, it is concluded that the consumption emphasis of chemical fertilizer shifts toward the central and western regions. （3） The decline of fertilizer consumption by grain crops was largely due to the decrease in sown area compared with the increase by vegetable crops attributable to the enlarging sown area; the increase by orchard crops was affected by both expanding the sown area and fertilizer use per unit area.
基金National Science-technology Support Plan Project, No.2012BAC 19B07 National Natural Science Foundation of China, No.41071044+2 种基金 No.41261016 No.41190084 Youth Teacher Scientific Capability Promoting Project of Northwest Normal University, No.NWNU-LKQN- 10-35
文摘As one of the areas with numerous lakes on the Tibetan Plateau, the Hoh Xil region plays an extremely important role in the fragile plateau eco-environment. Based on topographic maps in the 1970s and Landsat TM/ETM＋ remote sensing images iin the 1990s and the period from 2000 to 2011, the data of 83 lakes with an area above 10 km2 each were obtained by digitization method and artificial visual interpretation technology, and the causes for lake variations were also analyzed. Some conclusions can be drawn as follows. （1） From the 1970s to 2011, the lakes in the Hoh Xil region firstly shrank and then expanded, in particular, the area of lakes generally decreased during the 1970s-1990s. Then the lakes expanded from the 1990s to 2000 and the area was slightly higher than that in the 1970s. The area of lakes dramatically increased after 2000. （2） From 2000 to 2011, the lakes with different area ranks in the Hoh Xil region showed an overall expansion trend. Meanwhile, some regional differences were also discovered. Most of the lakes expanded and were widely distributed in the northern, central and western parts of the region. Some lakes were merged together or overflowed due to their rapid expansion. A small number of lakes with the trend of area decrease or strong fluctuation were scattered in the central and southern parts of the study area. And their variations were related to their own supply conditions or hydraulic connection with the downstream lakes or rivers. （3） The increase in precipitation was the dominant factor resulting in the expansion of lakes in the Hoh Xil region. The secondary factor was the increase in meltwater from glaciers and frozen soil due to climate warming.
基金supported by the Opening Foundation of the State Key Laboratory Breeding Base of Desertification and Aeolian Sand Disaster Combating,Gansu Desert Control Research Institute (GSDC201503)the National Natural Science Foundation of China (41271024,31260129,31360204)+1 种基金the Program for Innovative Research Group of Gansu Province,China (1506RJIA155)Lanzhou University for providing Arc GIS technical support in the data processing
文摘Analysis of spatial-temporal variations of desert vegetation under the background of climate changes can provide references for ecological restoration in arid and semi-arid areas. In this study, we used the Global Inventory Modeling and Mapping Studies （GIMMS） NDVI data from 1982 to 2006 and Moderate Resolution Imaging Spectroradiometer （MODIS） NDVI data from 2000 to 2013 to reveal the dynamics of desert vegetation in Hexi region of Northwest China over the past three decades. We also used the annual temperature and precipitation data acquired from the Chinese meteorological stations to analyze the response of desert vegetation to climatic variations. The average value of NDVImax （the maximum NDVI during the growing season） for desert vegetation in Hexi region increased at the rate of 0.65x10-3/a （P〈0.05） from 1982 to 2013, and the significant increases of NDVImax mainly appeared in the typical desert vegetation areas. Vegetation was significantly improved in the lower reaches of Shule and Shiyang river basins, and the weighted mean center of desert vegetation mainly shifted toward the lower reaches of the two basins. Almost 95.32% of the total desert vegetation area showed positive correlation between NDVImax and annual precipitation, indicating that precipitation is the key factor for desert vegetation growth in the entire study area. Moreover, the areas with non-significant positive correlation between NDVImax and annual precipitation mainly located in the lower reaches of Shiyang and Shule river basins, this may be due to human activities. Only 7.64% of the desert vegetation showed significant positive correlation between NDVImax and annual precipitation in the Shule River Basin （an extremely arid area）, indicating that precipitation is not the most important factor for vegetation growth in this basin, and further studies are needed to investigate the mechanism for this phenomenon.
基金The National Basic Research Program of China(973 Program),No.2012CB955304No.2009CB421403
文摘Runoff at the three time scales （non-flooding season, flooding season and annual period） was simulated and tested from 1958 to 2005 at Tangnaihai （Yellow River Source Region： YeSR）, Zhimenda （Yangtze River Source Region： YaSR） and Changdu （Lancang River Source Region： LcSR） by hydrological modeling, trend detection and comparative analysis. Also, future runoff variations from 2010 to 2039 at the three outlets were analyzed in A1B and B1 scenarios of CSIRO and NCAR climate model and the impact of climate change was tested. The results showed that the annual and non-flooding season runoff decreased significantly in YeSR, which decreased the water discharge to the midstream and down- stream of the Yellow River, and intensified the water shortage in the Yellow River Basin, but the other two regions were not statistically significant in the last 48 years. Compared with the runoff in baseline （1990s）, the runoff in YeSR would decrease in the following 30 years （2010-2039）, especially in the non-flooding season. Thus the water shortage in the mid- stream and downstream of the Yellow River Basin would be serious continuously. The runoff in YaSR would increase, especially in the flooding season, thus the flood control situation would be severe. The runoff in LcSR would also be greater than the current runoff, and the annual and flooding season runoff would not change significantly, while the runoff variation in the non-flooding season is uncertain. It would increase significantly in the B1 scenario of CSIRO model but decrease significantly in B1 scenario of NCAR model. Furlhermore, the most sensitive region to climate change is YaSR, followed by YeSR and LcSR.
基金The National Science and Technology Support Plan, No.2009BAC61B01
文摘Based on a monthly dataset of precipitation time series （1961-2010） from 12 me- teorological stations across the Three-River Headwater Region （THRHR） of Qinghai Province China, the spatio-temporal variation and abrupt change analysis of precipitation were exam- ined by using moving average, linear regression, spline interpolation, the Mann-Kendall test and so on. Major conclusions were as follows. （1） The long-term annual and seasonal pre- cipitation in the study area indicated an increasing trend with some oscillations during 1961-2010; however, the summer precipitation in the Lantsang （Lancang） River Headwater Region （LARHR）, and the autumn precipitation in the Yangtze River Headwater Region （YERHR） of the THRHR decreased in the same period. （2） The amount of annual precipita- tion in the THRHR and its three sub-headwater regions was greater in the 1980s and 2000s. The springs were fairly wet after the 1970s, while the summers were relatively wet in the 1960s, 1980s and 2000s. In addition, the amount of precipitation in the autumn was greater in the 1970s and 1980s, but it was relatively less for the winter precipitation, except in the 1990s （3） The normal values of spring, summer, winter and annual precipitation in the THRHR and its three sub-headwater regions all increased, but the normal value of summer precipitation in the LARHR had a negative trend and the normal value of winter precipitation declined in general. （4） The spring and winter precipitation increased in most of the THRHR. The summer autumn and annual precipitation increased mainly in the marginal area of the west and north and decreased in the regions of Yushu, Zaduo, Jiuzhi and Banma. （5） The spring and winter precipitation in the THRHR and its three sub-headwater regions showed an abrupt change, except for the spring precipitation in the YARHR. The abrupt changes of spring precipitation were mainly in the late 1980s and early 1990s, while the abrupt changes of winter precipita- tion were primary in the mid- to late 1970s. This research would be helpful for further under- standing the trends and periodicity of precipitation and for watershed-based water resource management in the THRHR.
基金The National Science and Technology Support Plan, No.2009BAC61B01
文摘In this study, a monthly dataset of temperature time series （1961-2010） from 12 meteorological stations across the Three-River Headwater Region of Qinghai Province （THRHR） was used to analyze the climate change. The temperature variation and abrupt change analysis were examined by using moving average, linear regression, Spline interpolation, Mann-Kendall test and so on. Some important conclusions were obtained from this research, which mainly contained four aspects as follows. （1） There were several cold and warm fluctuations for the annual and seasonal average temperature in the THRHR and its three sub-headwater regions, but the temperature in these regions all had an obviously rising trend at the statistical significance level, especially after 2001. The spring, summer, autumn and annual average temperature increased evidently after the 1990s, and the winter average temperature exhibited an obvious upward trend after entering the 21st century. Except the standard value of spring temperature, the annual and seasonal temperature standard value in the THRHR and its three sub-headwater regions increased gradually, and the upward trend for the standard value of winter average temperature indicated significantly. （2） The tendency rate of annual average temperature in the THRHR was 0.36℃ 10a^-1, while the tendency rates in the Yellow River Headwater Region （YERHR）, Lancangjiang River Headwater Region （LARHR） and Yangtze River Headwater Region （YARHR） were 0.37℃ 10a^-1, 0.37℃ 10a^-1 and 0.34℃10a^-1 respectively. The temperature increased significantly in the south of Yushu County and the north of Nangqian County. The rising trends of temperature in winter and autumn were higher than the upward trends in spring and summer. （3） The abrupt changes of annual, summer, autumn and winter average temperature were found in the THRHR, LARHR and YARHR, and were detected for the summer and autumn average temperature in the YERHR. The abrupt changes of annual and summer average temperatures were mainly in the late 1990s, while the abrupt changes of autumn and winter average temperatures appeared primarily in the early 1990s and the early 21st century respectively. （4） With the global warming, the diversities of altitude and underlying surface in different parts of the Tibetan Plateau were possibly the main reasons for the high increasing rate of temperature in the THRHR.
基金National Key Project of Fundamental Research SCSMEX.
文摘In this work, the National Center for Environmental Prediction/ National Center for Atmospheic Research (NCEP/ NCAR) global daily–mean reanalysis data are used to diagnose the features of the local circulation variation during the South China Sea (SCS) monsoon in 1998. It is found that by taking the appearance of southwest wind in lower layers and east wind in upper layers as the sign of the monsoon onset, the SCS monsoon starts on May 25 in 1998, which is later than that in normal years. The formation of the SCS monsoon is not a simple propagation of southwest monsoon in the north—south direction, but a process in which the southwest wind starts first over the north of the SCS, withdraws southward, and then propagates from south to north again. During this process, both meteorological elements and circulation fields change significantly. The outbreak of the SCS monsoon is the result of the seasonal variation of the height in lower and upper layers. The air rounding the Tibetan Plateau might be one of the dynamic reasons that make the summer monsoon start over the SCS at first. At the different stages of the monsoon, the vertical circulations as well as the lower and the upper layer divergence fields undergo evident temporal and regional changes. The SCS monsoon has the 60–day, 20–30–day and 8–15–day low frequency oscillations (LFOs), and dominant scale changes at the different stages of monsoon. The monsoon onset is related to the superimposition of the amplitudes of LFOs with different scales. Key words SCS monsoon - Circulation variation - Regional climate - LFO Sponsored by the National Key Project of Fundamental Research SCSMEX
基金supported by Guangdong Provincial Science and Technology Plan Provincial International Cooperation Project[No.2011B050700001].
文摘Pneumoconiosis is a restrictive lung disease mostly caused by occupational exposure to dust,including silica dust,asbestos,and other fibers.Inhalable particles smaller than 10μm can enter the bronchioles,injure lung cells,and induce lung fibrosis.This hard-to-cure disease places a substantial burden on patients and society[1].
基金National Natural Science Foundation of China, No.40501014 No.40871058
文摘The concentrations of heavy metals Ba, Pb, Cu, Zn and Co in snow pit collected in September, 2005 from the accumulation area of the East Rongbuk Glacier （6523 m a.s.l.）, which lies on the northern slope of Mt. Qomolangma, were determined by inductively coupled plasma mass spectrometry （ICP-MS）. Concentrations （pg/ml） of heavy metals are Ba2-227, Co2.8-15.7, Cu10-120, Zn29-4948 and Pb14-142, respectively. The 5180 was determined by MAT-252. The time period of the snow pit spans from autumn 2005 to summer 2004. Seasonal variations of the concentrations and δ^18O are observed, of which Pb, Cu, Zn and Co are much lower in summer monsoon season than that in non summer monsoon season, suggesting that different sources of heavy metals contributed to the site. EFc （crustal enrichment factors） is Co3.6, Cu27, Pb33 and Zn180, respectively. Higher EFo values of Pb, Cu and Zn suggest that Pb, Cu especially Zn are mainly contributed by anthropogenic sources.
基金supported by the Special Fund for Public Welfare Industry of Ministry of Water Resources of China(Grant No200901045)the Program for Changjiang Scholars and Innovative Research Team in University(Grant NoIRT0717)the 111 Project(Grant NoB08048)
文摘Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced by meteorological variables, it is necessary to investigate the extent to which different meteorological variables affect the potential evaporation. The aim of this study was to explore the variation trends of different meteorological variables, and their impacts on the potential evaporation. This study selected the Hailar Meteorological Station of the Hailar region, which is situated in a cold, semi-arid, and sub-humid region, as a case study site. Based on observed daily meteorological data from 1951 to 2009, the potential evaporation was calculated with the Penman formula, and the variations of meteorological variables were investigated with the nonparametric Mann-Kendall test. The correlation between the potential evaporation and each meteorological variable at annual and seasonal scales was also analyzed. The results show that the annual and seasonal potential evaporation and air temperature present increasing trends, whereas the wind speed, sunshine duration, and relative humidity present decreasing trends. Among the meteorological variables, the air temperature and relative humidity are the key factors that affect potential evaporation at different time scales, and the impacts of other meteorological variables on the potential evaporation are not significant and vary with time scales.
基金National 973 Program for Basic Research No.G1999043506
文摘Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.
基金supported by the National Natural Science Foundation of China[grant number 41176014]
文摘The wind field plays a decisive role in haze generation and dissipation processes over the Beijing- Tianjin-Hebei （BTH） region. Although geographically the BTH region is under the influence of the East Asian winter monsoon （EAWM）, this study finds that common indices of the EAWM cannot adequately describe the actual wind speed changes in the BTH region.Thus, observational data are used to analyze the interannual variations of the winter wind field over the BTH region. The results show that the average winter wind speed is 2.0 m s-1, with a slight rate of decline of 0.01 m s-1 yr-1. In most cases, strong-wind years correspond to negative sea surface temperature （SST） anomalies over the tropical Pacific, whereas weak-wind years correspond to positive SST anomalies. Moreover, correlation and composite analyses show that the interannual variability is affected by multiple factors, including the following： （1） the pressure gradient in the high and middle latitudes of the Northern Hemisphere, as in strong-wind years the pressure gradient helps cold air move from high latitudes to middle latitudes; （2） the skin temperature in Eurasia, as low skin temperature in Eurasia in strong-wind years is conducive to the accumulation of cold air; and （3） the SST of the tropical Pacific east of the Philippines, as in strong-wind years the high temperature of this area affects the BTH region through anticyclonic activity and associated tropical circulation systems.
基金Supported by the Deanship for Scientific Research,King Saud University,Riyadh,Kingdom of Saudi Arabia,No.RGP-1436-007
文摘BACKGROUND Incidence and severity variations of inflammatory bowel disease(IBD)have been reported from Western populations between continents and regions of the same countries.However,no data were available from other countries.AIM To investigate the regional differences in the IBD profiles of pediatric patients from the Kingdom of Saudi Arabia.METHODS Data from a national multicenter IBD study were used.The incidence,time trend,and clinical presentation of Crohn’s disease(CD)and ulcerative colitis(UC)in the Central region(CR),Western region(WR),and Eastern region(ER)were analyzed and compared.Statistical analysis included Poisson regression analysis for incidence variation and Chi-square test for demographic and clinical parameters.A P<0.05 was considered significant.RESULTS The prevalence of positive family history was lower in children with CD from the ER than the CR or the WR.Consanguinity rate was higher in children with CD and UC from the CR and the ER,respectively.The incidences and time trends of CD and UC were not significantly different between regions.In the ER,a significantly higher percentage of children with CD presented with abdominal pain(P<0.001),blood in stools(P=0.048),stricturing or penetrating disease(P=0.029),higher erythrocyte sedimentation rate(P<0.001),higher C-reactive protein(P<0.001),higher anemia(P=0.017),and lower albumin level(P=0.014).For children with UC from the ER,a significantly higher percentage presented with anemia(P=0.006)and a lower percentage with pancolitis(P<0.001).CONCLUSION The most important finding is the identification of significantly more severe presentation of CD in the ER of the Kingdom of Saudi Arabia.Prospective studies are needed to explain such variations.
文摘The West Development Policy being implemented in China is causing significant land use and land cover （LULC） changes in West China. With the up-to-date satellite database of the Global Land Cover Characteristics Database （GLCCD） that characterizes the lower boundary conditions, the regional climate model RIEMS-TEA is used to simulate possible impacts of the significant LULC variation. The model was run for five continuous three-month periods from 1 June to 1 September of 1993, 1994, 1995, 1996, and 1997, and the results of the five groups are examined by means of a student t-test to identify the statistical significance of regional climate variation. The main results are： （1） The regional climate is affected by the LULC variation because the equilibrium of water and heat transfer in the air-vegetation interface is changed. （2） The integrated impact of the LULC variation on regional climate is not only limited to West China where the LULC varies, but also to some areas in the model domain where the LULC does not vary at all. （3） The East Asian monsoon system and its vertical structure are adjusted by the large scale LULC variation in western China, where the consequences are the enhancement of the westward water vapor transfer from the east oast and the relevant increase of wet-hydrostatic energy in the middle-upper atmospheric layers. （4） The ecological engineering in West China affects significantly the regional climate in Northwest China, North China and the middle-lower reaches of the Yangtze River; there are obvious effects in South, Northeast, and Southwest China, but minor effects in Tibet.
基金partially supported and funded by Chongqing Research Program of Basic Research and Frontier Technology (Grant No. cstc2017jcyj B0317)Chongqing University Innovation Team Building Plan (Grant No. CXTDX201601017)Science and Technology Project of Chongqing Municipal Education Commission (Grant No. KJ1738462)
文摘A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotranspiration(PET) was predicted using a modified Penman-Monteith(P-M) model. The region's ratio of precipitation to evapotranspiration was calculated as the humidity index(HI). The data obtained was used to analyze climatic responses to land cover conversions from the perspectives of evapotranspiration and humidity variations. The results show that, from 1997 to 2009, the average annual PET increased in the early years and decreased later. In terms of overall spatial distribution, a significant reciprocal relationship appeared between annual PET and annual HI. In 1997,the annual PET was higher in the lower reaches than in the upper reaches of the TGRR, but the areas with high PET shifted substantially westward by 2003. The annual PET continued to increase in 2006, but the areas with high PET shrank by 2009. In contrast, the annual HI showed varying degrees of localized spatial variability. Over the three periods, the dominantforms of land cover conversions occurred from evergreen cover to seasonal green cover, from seasonal green cover to evergreen cover, and from seasonal green cover to seasonally inundated areas, respectively. These accounted for 48.0%, 38.4%, and 23.8% of the total areas of converted land covers in the three periods, respectively. During the period between 1997 and 2003, the main forms of land cover conversions resulted in both positive and negative growths in the average annual PET, while all of them pushed down the average annual HI. From 2003 to 2006, the reservoir region experienced neither a decrease in the annual PET nor an increase in the annual HI. The period between 2006 and 2009 saw a consistent downward trend in the annual PET and a consistent upward trend in the annual HI.
