In order to reveal the complex network characteristics and evolution principle of China aviation network,the relationship between the node degree and the average path length of China aviation network in 1988,1994,2001...In order to reveal the complex network characteristics and evolution principle of China aviation network,the relationship between the node degree and the average path length of China aviation network in 1988,1994,2001,2008 and 2015 was studied.According to the theory and method of complex network,the network system was constructed with the city where the airport was located as the network node and the airline as the edge of the network.On the basis of the statistical data,the node average path length of China aviation network in 1988,1994,2001,2008 and 2015 was calculated.Through regression analysis,it was found that the node degree had a logarithmic relationship with the average length of node path,and the two parameters of the logarithmic relationship had linear evolutionary trace.Key word:China aviation network,complex network,node degree,average length of node path,logarithmic relationship,evolutionary trace.展开更多
In order to reveal the complex network characteristics and evolution principle of China aviation network,the relationship between the average degree and the average path length of edge vertices of China aviation netwo...In order to reveal the complex network characteristics and evolution principle of China aviation network,the relationship between the average degree and the average path length of edge vertices of China aviation network in 1988,1994,2001,2008 and 2015 was studied.According to the theory and method of complex network,the network system was constructed with the city where the airport was located as the network node and the airline as the edge of the network.On the basis of the statistical data,the average degree and average path length of edge vertices of China aviation network in 1988,1994,2001,2008 and 2015 were calculated.Through regression analysis,it was found that the average degree had a logarithmic relationship with the average path length of edge vertices and the two parameters of the logarithmic relationship had linear evolutionary trace.展开更多
Understanding the distribution,dispersal,and correlation of modern pollen with vegetation in mountainous regions is essential for establishing accurate modern analogs for fossil pollen records.This study,conducted in ...Understanding the distribution,dispersal,and correlation of modern pollen with vegetation in mountainous regions is essential for establishing accurate modern analogs for fossil pollen records.This study,conducted in Leigong Mountain on the YunnanGuizhou Plateau of southwestern China,involved the collection of 35 surface soil samples from diverse vegetation communities along an elevational gradient ranging from 1210 to 1875 meters.The results reveal a close correspondence between modern pollen assemblages and vegetation zones.Principal Component Analysis(PCA)results indicate that pollen assemblages can effectively distinguish between subtropical montane evergreen broad-leaved forest(SEBF)and subtropical montane deciduous broadleaved forest(SDBF).However,both SEBF and SDBF show significant overlap with subtropical montane evergreen-deciduous broad-leaved mixed forest(SEMF).Detrended Correspondence Analysis(DCA)results clearly distinguish the three vegetation zones,and the first axis of DCA shows a significant positive correlation with elevation(p<0.01,R=0.48).Discriminant Analysis(DA)successfully assigns 94.4%of the modern pollen samples to their respective vegetation zones.Pollen taxa such as Impatiens,Astertype,and Rosaceae exhibit significant indicative capabilities for the SEBF zone,effectively distinguishing this vegetation zone from others.Pinus and Alnus display overrepresentation in the Leigong Mountain region,while Quercus(D,deciduous-type)and Poaceae exhibit high representation in the SEBF zone.In the SEBF zone,both pollen diversity and richness are the lowest.Our study reveals the complex relationship between the richness and diversity of pollen and vegetation.The diversity and richness of tree and shrub pollen are found to be lower than those of the corresponding plants.The pollen-vegetation relationship elucidated in this study serves as a critical reference for reconstructing ancient environments from fossil pollen retrieved in this region.展开更多
To study the quantitative relationship between surface sedimentary diatoms and water depth,67 surface samples were collected for diatom analysis on eight profiles with water depth variation from the muddy intertidal z...To study the quantitative relationship between surface sedimentary diatoms and water depth,67 surface samples were collected for diatom analysis on eight profiles with water depth variation from the muddy intertidal zone to the shallow sea area in North-Central Bohai Bay,China.The results showed that the distribution of diatoms changed significantly in response to the change in water depth.Furthermore,the quantitative relationship between the distribution of dominant diatom species,their assemblages,and the water depth was established.The water depth optima for seven dominant species such as Cyclotella striata/stylorum,Paralia sulcata,and Coscinodiscus perforatus and the water depth indication range of seven diatom assemblages were obtained in the study area above the water depth(elevation)of-10 m.The quantitative relationship between surface sedimentary diatoms and water depth provides a proxy index for diatom-paleo-water depth reconstruction in the strata in Bohai Bay,China.展开更多
In order to reveal the complex network characteristics and evolution principle of China aviation network, the relationship between the node degree and the nearest neighbor average degree and its evolution trace of Chi...In order to reveal the complex network characteristics and evolution principle of China aviation network, the relationship between the node degree and the nearest neighbor average degree and its evolution trace of China aviation network in 1988, 1994, 2001, 2008 and 2015 were studied. According to the theory and method of complex network, the network system was constructed with the city where the airport was located as the network node and the airline as the edge of the network. According to the statistical data, the node nearest neighbor average degree of China aviation network in 1988, 1994, 2001, 2008 and 2015 was calculated. Through regression analysis, it was found that the node degree had a negative exponential relationship with the nearest neighbor average degree, and the two parameters of the negative exponential relationship had linear evolution trace.展开更多
Depending on the analysis of the coeval sedimentary geometry and subsidence mechanism in the Longmen Shan foreland basin, three models about the coupling relationship between Longmen Shan uplift and foreland basin sub...Depending on the analysis of the coeval sedimentary geometry and subsidence mechanism in the Longmen Shan foreland basin, three models about the coupling relationship between Longmen Shan uplift and foreland basin subsidence since the Indosinian have been proposed:(1) crustal shortening and its related wide wedge-shaped foreland basin,(2) crustal isostatic rebound and its related tabular foreland basin, and(3) lower crustal flow and its related narrow wedge-shaped foreland basin. Based on the narrow wedge-shaped foreland basin developed since 4 Ma, it is believed that the narrow crustal shortening and tectonic load driven by lower crustal flow is a primary driver for the present Longmen Shan uplift and the Wenchuan(Ms 8.0) earthquake.展开更多
This study investigates the relationship between tropical cyclone-induced precipitation(P_(TC)) and summer monsoon-induced precipitation(P_(SM)) in southern China(SC) during June-August.The spatial patterns ...This study investigates the relationship between tropical cyclone-induced precipitation(P_(TC)) and summer monsoon-induced precipitation(P_(SM)) in southern China(SC) during June-August.The spatial patterns of the first interannual mode are uniform in sign over SC,with positive anomalies for P_(TC) and negative anomalies for P_(SM).The background of an increase in cyclonic vorticity,an increase in RH,and a decrease in vertical wind shear over the South China Sea(SCS)-western north Pacific(WNP) provides favorable conditions for more TC genesis.The positive equatorial central Pacific SST anomaly and negative North Indian Ocean SST anomaly contribute to the anomalous cyclone over the SCS-WNP,which causes decreasing P_(SM) in SC together with an anomalous anticyclone over eastern China-Japan.By contrast,whilst the spatial patterns of the first interdecadal mode are also uniform in sign over SC,there are positive anomalies for both P_(TC) and P_(SM).The first interdecadal principal component features significant positive correlation with the number of TCs forming in the SCS.There is a significant increase in P_(TC) and P_(SM) after early 1990 s.A positive tropical Indian Ocean(TIO) SST anomaly persists from the preceding winter to summer.During the preceding winter and spring after the early 1990 s,a positive western Pacific SST anomaly can result in TIO SST warming through vertical circulation.Then,the positive TIO SST anomaly triggers an anomalous WNP anticyclone and contributes to the interdecadal increase in SC P_(SM) in the succeeding summer.The persistent heating source over SC from May to summer related to an earlier onset of the SCS monsoon may strengthen the East Asian subtropical summer monsoon.展开更多
Quantile regression(QR) is proposed to examine the relationships between large-scale atmospheric variables and all parts of the distribution of daily precipitation amount at Beijing Station from 1960 to 2008. QR is ...Quantile regression(QR) is proposed to examine the relationships between large-scale atmospheric variables and all parts of the distribution of daily precipitation amount at Beijing Station from 1960 to 2008. QR is also applied to evaluate the relationship between large-scale predictors and extreme precipitation(90th quantile) at 238 stations in northern China.Finally, QR is used to fit observed daily precipitation amounts for wet days at four sample stations. Results show that meridional wind and specific humidity at both 850 h Pa and 500 h Pa(V850, SH850, V500, and SH500) strongly affect all parts of the Beijing precipitation distribution during the wet season(April–September). Meridional wind, zonal wind, and specific humidity at only 850 h Pa(V850, U850, SH850) are significantly related to the precipitation distribution in the dry season(October–March). Impacts of these large-scale predictors on the daily precipitation amount with higher quantile become stronger, whereas their impact on light precipitation is negligible. In addition, SH850 has a strong relationship with wet-season extreme precipitation across the entire region, whereas the impacts of V850, V500, and SH500 are mainly in semi-arid and semi-humid areas. For the dry season, both SH850 and V850 are the major predictors of extreme precipitation in the entire region. Moreover, QR can satisfactorily simulate the daily precipitation amount at each station and for each season, if an optimum distribution family is selected. Therefore, QR is valuable for detecting the relationship between the large-scale predictors and the daily precipitation amount.展开更多
Relationship between eating quality(EQ)andphysico-chemical properties of 78 high grainquality rice varieties,45 indica and 33 japoni-ca,were studied in 1995.The samples werecollected from different rice growing region...Relationship between eating quality(EQ)andphysico-chemical properties of 78 high grainquality rice varieties,45 indica and 33 japoni-ca,were studied in 1995.The samples werecollected from different rice growing regions in20 provinces.The physico-chemical proper-ties,including grain length(GL),length towidth ratio(L/W),chalky grain rate(CG),chalkiness(CH),translucency(TR),gela-tinization temperature(GT,measured by alka-li spreading value),gel consistency(CA2),amylase content(AC),and protein content(PC)were measured according to the standard展开更多
Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundat...Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes.展开更多
The paper deals mainly with the relationship between the microtexture types and the indices of physicomechanical properties of loess. The results of study demonstrate that the study of microtextures of loess is of imp...The paper deals mainly with the relationship between the microtexture types and the indices of physicomechanical properties of loess. The results of study demonstrate that the study of microtextures of loess is of importance in the prediction and preliminary evaluation of engineering geological properties of loess in a region.展开更多
Sino-US relations are complex relations with multi-aspects between the two bigcountries in the world. It has three levels: the global level, the Asia-Pacificlevel and the bilateral level. The critical relationship bet...Sino-US relations are complex relations with multi-aspects between the two bigcountries in the world. It has three levels: the global level, the Asia-Pacificlevel and the bilateral level. The critical relationship between China and the US isembodied in the regional and bilateral levels that are more specific and essential.Beyond the field of economy and trade, their relationship is mainly embodied in thestrategic and security field.展开更多
The relationship between human beings and nature influences the expressions and manifestations of literature. Literature can spy on the nature exploration of human society and ideological values in the thinking and be...The relationship between human beings and nature influences the expressions and manifestations of literature. Literature can spy on the nature exploration of human society and ideological values in the thinking and behavior patterns,expressing the relationship between human beings and nature. Through expressions of literature in China and the West,we draw lessons from W estern literary expressions in the developing relationship between man and nature,and get inspiration for the development of Chinese literature.展开更多
Atmospheric nitrogen(N)deposition has experienced significant change because of anthropogenic emissions,thereby exert-ing a pronounced impact on global ecosystem services.With the rapid development of industry and agr...Atmospheric nitrogen(N)deposition has experienced significant change because of anthropogenic emissions,thereby exert-ing a pronounced impact on global ecosystem services.With the rapid development of industry and agriculture and the swift expansion of urban areas in China since the 1980s,reactive nitrogen(Nr)emissions and N deposition have substantially increased.In pursuit of im-proving air quality,China has implemented a series of environmental protection policies and undertaken diverse measures to reduce pol-lutant emissions.This paper is a review of multivariate data sources of atmospheric N deposition based on the results of literature from 1980 to 2023,and the original data from 1980 to 2020 are summarized,counted and calculated.The main findings are as follows:1)the annual average atmospheric N deposition ranged from approximately 20-40 kg/(ha·yr),with the variability primarily linked to different assessment methods;2)regional disparities were evident in the spatial distribution of N deposition,with elevated values concentrated in areas with intense Nr emissions;3)atmospheric N deposition significantly declined after 2010,particularly the deposition of oxidized N,while reduced N deposition remained stable.These results reflect the effects of China's serious control policies on nitrogen oxide(NO.)emissions and strengthen the importance of agricultural NH3 emission mitigation.This study contributes to a comprehensive understand-ing of the N dynamics in the emission-deposition process,and provides a scientific foundation for the research of environmental protec-tion,climate change,and sustainable development.展开更多
One specimen belonging to the family Comatellinae was collected from the Zhenbei Seamount(332.5–478.2 m)in the South China Sea in July 2022.Based on the morphological characters,the specimen was identified as Palaeoc...One specimen belonging to the family Comatellinae was collected from the Zhenbei Seamount(332.5–478.2 m)in the South China Sea in July 2022.Based on the morphological characters,the specimen was identified as Palaeocomatella hiwia McKnight,1977.It is first recorded from China Sea and redescribed in detail.This specimen differs from the original description from New Zealand for never showing syzygy at br4+5 or br5+6 on interior and br1+2 on exterior arms.However,it is much conform to the redescription to specimens from Indonesia,with only differences in position of the second syzygy and distalmost pinnule comb.Specimen is deposited in the Institute of Oceanology,Chinese Academy of Sciences.Phylogenetic analyses based on the mitochondrial c oxidase subunit I(COI)and 16S rRNA genes indicated that P.hiwia was nested within the tribe Phanogeniini and clustered with Aphanocomaster pulcher.Furthermore,P.hiwia showed same morphological features in terms of mouth placement,comb location,and number of comb teeth rows as other genera of Phanogeniini.Therefore,we suggest that the genus Palaeocomatella should be put in the tribe Phanogeniini.展开更多
Background: The Air Force Health Study collected reproductive outcomes for live-born children of male Air Force veterans of the Vietnam War. Methods: Dioxin values for participants were obtained from blood samples. An...Background: The Air Force Health Study collected reproductive outcomes for live-born children of male Air Force veterans of the Vietnam War. Methods: Dioxin values for participants were obtained from blood samples. Analyses were conducted of occurrence of 16 specific categories of birth defects and developmental disabilities. Children were categorized as conceived before and after the start of participants’ Vietnam War service. Children conceived before the start of Vietnam War service were treated as being conceived when their fathers had unquantifiable dioxin values. Children conceived after the start of Vietnam War service for participants with missing dioxin values were excluded from primary analyses, but were used to assess the impact of their exclusion on conclusions. Correlation between values for specific categories for multiple children fathered by the same participant was accounted for. The dose-response relationship was treated as a step function increasing for dioxin values larger than adaptively identified individual thresholds changing with the specific category. Results: For 15 of 16 specific categories, the probability of occurrence increased substantially for a sufficiently high dioxin level above identified thresholds. Exclusion of children due to missing dioxin likely did not affect these results. Conclusions: Results supported the conclusion of substantial adverse effects on a wide variety of specific categories of birth defects and developmental disabilities due to sufficiently high exposures to dioxin, a toxic contaminant of Agent Orange used for herbicide spraying in the Vietnam War. Results may hold more generally, but might also have been affected by a variety of limitations.展开更多
By means of ERA-40, JRA-25, NCEP/NCAR and NCEP/DOE reanalysis data, empirical relations between precipitable water and surface vapor pressure in spatial and temporal scale were calculated. The reliabilities of precipi...By means of ERA-40, JRA-25, NCEP/NCAR and NCEP/DOE reanalysis data, empirical relations between precipitable water and surface vapor pressure in spatial and temporal scale were calculated. The reliabilities of precipitable water from reanalysis data were validated based on comparing different W-e empirical relations of various reanalysis data, in order to provide basis and reference for reasonable application. The results showed that W-e empirical relation of ERA-40 was closest to that of sounding data in China, and precipitable water from ERA-40 was the most credible. The worldwide comparison among W-e empirical relations of four reanalysis data showed that there was little difference in annual mean W-e empirical relations in the middle latitudes and great differences in low and high latitudes. Seasonal mean W-e empirical relations in the middle latitudes of the northern Hemisphere had little difference in spring, autumn and winter, but great difference in summer. Therefore, the reliabilities of precipitable water from reanalysis data in spring, autumn and winter in the middle latitudes of the northern hemisphere were higher than other areas and seasons. W-e empirical relations of NCEP/NCAR and NCEP/DOE had good stability in different years, while there was poor stability in ERA-40 and JRA-25.展开更多
Purpose-Following the regional restructuring,the number of joint-venture railway companies in which the Group participates has significantly increased.This paper aims to explore the challenges faced by China Railway G...Purpose-Following the regional restructuring,the number of joint-venture railway companies in which the Group participates has significantly increased.This paper aims to explore the challenges faced by China Railway Group in managing participation in joint-venture railway companies.The study seeks to propose specific approaches to ensure the effective management of these companies,thereby maximizing the benefits of the regional restructuring and supporting the development of a strong transportation country and a modern infrastructure system.Design/methodology/approach-Based on the change in the shareholding relationship between China Railway Group and the joint-venture railway companies,and considering the current situation of the regional restructuring of these companies,as well as the insights from existing literature and typical case studies,this paper proposes some specific paths for effective management of joint-stock railway companies which China Railway Group participated in.Findings-The problems in participation management are the unclear dual leadership role of the party committee,the lack of discourse power,the lack of synergy between shareholders,the increasing risk of sustainable operation of the loss-making companies and the role of dispatched personnel is not fully played.Based on the theories,combined with the existing research and practical cases,the paper proposed specific approaches,such as perfecting top-level system design,maintaining the discourse power,carrying out differentiated management,arranging personnel rationally,arranging shareholders synergy,and innovating methods to provide references for China Railway Group’s subsequent management of joint venture railway companies.Originality/value-This paper contributes to the existing literature by providing a comprehensive analysis of the challenges faced by China Railway Group in managing participation in joint-venture railway companies following the regional restructuring.The study offers novel insights and practical recommendations for addressing these challenges.The findings can serve as valuable references for China Railway Group’s subsequent management of joint-venture railway companies which participated in,as well as for other stateowned enterprises facing similar challenges in managing their joint ventures.展开更多
In the post-pandemic era,the global economic and security landscapes are fraught with complexities and uncertainties.Among them,four risk flashpoints merit attention:Certain countries are raising interest rates to sub...In the post-pandemic era,the global economic and security landscapes are fraught with complexities and uncertainties.Among them,four risk flashpoints merit attention:Certain countries are raising interest rates to subdue inflation,despite their already high levels of debt;the bulk commodities market is experiencing volatility,leading to global turbulence and change;trade protectionism is at the forefront of major-power rivalry in political and economic spheres;and regional security crises are compounding international tensions.Behind those flashpoints are contradictions that obstruct world peace and progress,including development imbalances,governance gaps,and structural tensions in global security.In the face of uncertainties,it is crucial for China to seize strategic opportunities and transform crises into favorable situations.China has launched the Global Development Initiative(GDI)and the Global Security Initiative(GSI)to contribute to global prosperity and security.The two initiatives demonstrate China’s commitment to addressing global deficits in peace,development,security,and governance.展开更多
The orderly transfer of the manufacturing industry is a major action in China’s industrial restructuring.From the perspective of industrial transfer,we used the concentration ratio to depict the trend of the industri...The orderly transfer of the manufacturing industry is a major action in China’s industrial restructuring.From the perspective of industrial transfer,we used the concentration ratio to depict the trend of the industrial transfer of energy-intensive manufacturing in the eastern,central,and western regions since the policy of large-scale development of western China was implemented.We measured the total factor productivity(TFP)of western China using the DEAMalmquist index method.We conducted a regression analysis to measure the effect of western China’s undertaking of the transfer of the energy-intensive manufacturing industry.The findings of this study show that during 2000–2019,eleven provinces(as well as autonomous regions and municipalities)in western China undertook the transfer of the energy-intensive manufacturing industry from the eastern and central regions to varying degrees,exhibiting significant phase features regarding the rate and scale of transfers.Further investigation also demonstrated that the transfer of energy-intensive manufacturing industries has a U-shaped enabling effect on TFP in western China with the scale effect greater than the technology effect.Therefore,it is necessary to transition from“extensive industrial transfer”at the cost of the labor force,land,and resources to“modern industrial transfer”featured by technology and efficiency improvements to contribute to industrial restructuring in western China effectively.展开更多
文摘In order to reveal the complex network characteristics and evolution principle of China aviation network,the relationship between the node degree and the average path length of China aviation network in 1988,1994,2001,2008 and 2015 was studied.According to the theory and method of complex network,the network system was constructed with the city where the airport was located as the network node and the airline as the edge of the network.On the basis of the statistical data,the node average path length of China aviation network in 1988,1994,2001,2008 and 2015 was calculated.Through regression analysis,it was found that the node degree had a logarithmic relationship with the average length of node path,and the two parameters of the logarithmic relationship had linear evolutionary trace.Key word:China aviation network,complex network,node degree,average length of node path,logarithmic relationship,evolutionary trace.
文摘In order to reveal the complex network characteristics and evolution principle of China aviation network,the relationship between the average degree and the average path length of edge vertices of China aviation network in 1988,1994,2001,2008 and 2015 was studied.According to the theory and method of complex network,the network system was constructed with the city where the airport was located as the network node and the airline as the edge of the network.On the basis of the statistical data,the average degree and average path length of edge vertices of China aviation network in 1988,1994,2001,2008 and 2015 were calculated.Through regression analysis,it was found that the average degree had a logarithmic relationship with the average path length of edge vertices and the two parameters of the logarithmic relationship had linear evolutionary trace.
基金supported by the National Natural Science Foundation of China(grant numbers 42171157,42107475 and 41907379)College Students'Innovation and Entrepreneurship Program of Nantong University,and Foundation of Hunan Province(2023JJ40099 and 23B0678)。
文摘Understanding the distribution,dispersal,and correlation of modern pollen with vegetation in mountainous regions is essential for establishing accurate modern analogs for fossil pollen records.This study,conducted in Leigong Mountain on the YunnanGuizhou Plateau of southwestern China,involved the collection of 35 surface soil samples from diverse vegetation communities along an elevational gradient ranging from 1210 to 1875 meters.The results reveal a close correspondence between modern pollen assemblages and vegetation zones.Principal Component Analysis(PCA)results indicate that pollen assemblages can effectively distinguish between subtropical montane evergreen broad-leaved forest(SEBF)and subtropical montane deciduous broadleaved forest(SDBF).However,both SEBF and SDBF show significant overlap with subtropical montane evergreen-deciduous broad-leaved mixed forest(SEMF).Detrended Correspondence Analysis(DCA)results clearly distinguish the three vegetation zones,and the first axis of DCA shows a significant positive correlation with elevation(p<0.01,R=0.48).Discriminant Analysis(DA)successfully assigns 94.4%of the modern pollen samples to their respective vegetation zones.Pollen taxa such as Impatiens,Astertype,and Rosaceae exhibit significant indicative capabilities for the SEBF zone,effectively distinguishing this vegetation zone from others.Pinus and Alnus display overrepresentation in the Leigong Mountain region,while Quercus(D,deciduous-type)and Poaceae exhibit high representation in the SEBF zone.In the SEBF zone,both pollen diversity and richness are the lowest.Our study reveals the complex relationship between the richness and diversity of pollen and vegetation.The diversity and richness of tree and shrub pollen are found to be lower than those of the corresponding plants.The pollen-vegetation relationship elucidated in this study serves as a critical reference for reconstructing ancient environments from fossil pollen retrieved in this region.
基金supported by the National Natural Science Foundation of China Youth Fund(41806109)the project of the China Geological Survey(DD20189506)。
文摘To study the quantitative relationship between surface sedimentary diatoms and water depth,67 surface samples were collected for diatom analysis on eight profiles with water depth variation from the muddy intertidal zone to the shallow sea area in North-Central Bohai Bay,China.The results showed that the distribution of diatoms changed significantly in response to the change in water depth.Furthermore,the quantitative relationship between the distribution of dominant diatom species,their assemblages,and the water depth was established.The water depth optima for seven dominant species such as Cyclotella striata/stylorum,Paralia sulcata,and Coscinodiscus perforatus and the water depth indication range of seven diatom assemblages were obtained in the study area above the water depth(elevation)of-10 m.The quantitative relationship between surface sedimentary diatoms and water depth provides a proxy index for diatom-paleo-water depth reconstruction in the strata in Bohai Bay,China.
文摘In order to reveal the complex network characteristics and evolution principle of China aviation network, the relationship between the node degree and the nearest neighbor average degree and its evolution trace of China aviation network in 1988, 1994, 2001, 2008 and 2015 were studied. According to the theory and method of complex network, the network system was constructed with the city where the airport was located as the network node and the airline as the edge of the network. According to the statistical data, the node nearest neighbor average degree of China aviation network in 1988, 1994, 2001, 2008 and 2015 was calculated. Through regression analysis, it was found that the node degree had a negative exponential relationship with the nearest neighbor average degree, and the two parameters of the negative exponential relationship had linear evolution trace.
基金funded by China National Natural Science Foundation(No:41372114,41502116,41340005,40841010,40972083,41172162,and 41402159)geological survey from China Geological Survey(No:121201010000150004–08 and 12120115004501–01)the project of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(No:SK–0801)
文摘Depending on the analysis of the coeval sedimentary geometry and subsidence mechanism in the Longmen Shan foreland basin, three models about the coupling relationship between Longmen Shan uplift and foreland basin subsidence since the Indosinian have been proposed:(1) crustal shortening and its related wide wedge-shaped foreland basin,(2) crustal isostatic rebound and its related tabular foreland basin, and(3) lower crustal flow and its related narrow wedge-shaped foreland basin. Based on the narrow wedge-shaped foreland basin developed since 4 Ma, it is believed that the narrow crustal shortening and tectonic load driven by lower crustal flow is a primary driver for the present Longmen Shan uplift and the Wenchuan(Ms 8.0) earthquake.
基金jointly supported by the National Department Public Benefit Research Foundation[grant number GYHY201406003]the Guangdong Natural Science Foundation[grant numbers 2016A030310113,2016A030310015]+2 种基金the National Natural Science Foundation of China[grant numbers41506004,41506003]support from the National Natural Science Foundation of China to Zhi-Ping Wen[grant number 41530530]the Young Scientist Support Program2012,sponsored by the APEC Climate Center
文摘This study investigates the relationship between tropical cyclone-induced precipitation(P_(TC)) and summer monsoon-induced precipitation(P_(SM)) in southern China(SC) during June-August.The spatial patterns of the first interannual mode are uniform in sign over SC,with positive anomalies for P_(TC) and negative anomalies for P_(SM).The background of an increase in cyclonic vorticity,an increase in RH,and a decrease in vertical wind shear over the South China Sea(SCS)-western north Pacific(WNP) provides favorable conditions for more TC genesis.The positive equatorial central Pacific SST anomaly and negative North Indian Ocean SST anomaly contribute to the anomalous cyclone over the SCS-WNP,which causes decreasing P_(SM) in SC together with an anomalous anticyclone over eastern China-Japan.By contrast,whilst the spatial patterns of the first interdecadal mode are also uniform in sign over SC,there are positive anomalies for both P_(TC) and P_(SM).The first interdecadal principal component features significant positive correlation with the number of TCs forming in the SCS.There is a significant increase in P_(TC) and P_(SM) after early 1990 s.A positive tropical Indian Ocean(TIO) SST anomaly persists from the preceding winter to summer.During the preceding winter and spring after the early 1990 s,a positive western Pacific SST anomaly can result in TIO SST warming through vertical circulation.Then,the positive TIO SST anomaly triggers an anomalous WNP anticyclone and contributes to the interdecadal increase in SC P_(SM) in the succeeding summer.The persistent heating source over SC from May to summer related to an earlier onset of the SCS monsoon may strengthen the East Asian subtropical summer monsoon.
基金jointly sponsored by the National Basic Research Program of China "973" Program (Grant No. 2012CB956203)the Knowledge Innovation Project (Grant No. KZCX2-EW-202)the National Natural Science Foundation of China (Grant Nos. 91325108 and 51339004)
文摘Quantile regression(QR) is proposed to examine the relationships between large-scale atmospheric variables and all parts of the distribution of daily precipitation amount at Beijing Station from 1960 to 2008. QR is also applied to evaluate the relationship between large-scale predictors and extreme precipitation(90th quantile) at 238 stations in northern China.Finally, QR is used to fit observed daily precipitation amounts for wet days at four sample stations. Results show that meridional wind and specific humidity at both 850 h Pa and 500 h Pa(V850, SH850, V500, and SH500) strongly affect all parts of the Beijing precipitation distribution during the wet season(April–September). Meridional wind, zonal wind, and specific humidity at only 850 h Pa(V850, U850, SH850) are significantly related to the precipitation distribution in the dry season(October–March). Impacts of these large-scale predictors on the daily precipitation amount with higher quantile become stronger, whereas their impact on light precipitation is negligible. In addition, SH850 has a strong relationship with wet-season extreme precipitation across the entire region, whereas the impacts of V850, V500, and SH500 are mainly in semi-arid and semi-humid areas. For the dry season, both SH850 and V850 are the major predictors of extreme precipitation in the entire region. Moreover, QR can satisfactorily simulate the daily precipitation amount at each station and for each season, if an optimum distribution family is selected. Therefore, QR is valuable for detecting the relationship between the large-scale predictors and the daily precipitation amount.
文摘Relationship between eating quality(EQ)andphysico-chemical properties of 78 high grainquality rice varieties,45 indica and 33 japoni-ca,were studied in 1995.The samples werecollected from different rice growing regions in20 provinces.The physico-chemical proper-ties,including grain length(GL),length towidth ratio(L/W),chalky grain rate(CG),chalkiness(CH),translucency(TR),gela-tinization temperature(GT,measured by alka-li spreading value),gel consistency(CA2),amylase content(AC),and protein content(PC)were measured according to the standard
文摘Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes.
文摘The paper deals mainly with the relationship between the microtexture types and the indices of physicomechanical properties of loess. The results of study demonstrate that the study of microtextures of loess is of importance in the prediction and preliminary evaluation of engineering geological properties of loess in a region.
文摘Sino-US relations are complex relations with multi-aspects between the two bigcountries in the world. It has three levels: the global level, the Asia-Pacificlevel and the bilateral level. The critical relationship between China and the US isembodied in the regional and bilateral levels that are more specific and essential.Beyond the field of economy and trade, their relationship is mainly embodied in thestrategic and security field.
文摘The relationship between human beings and nature influences the expressions and manifestations of literature. Literature can spy on the nature exploration of human society and ideological values in the thinking and behavior patterns,expressing the relationship between human beings and nature. Through expressions of literature in China and the West,we draw lessons from W estern literary expressions in the developing relationship between man and nature,and get inspiration for the development of Chinese literature.
基金Under the auspices of the National Natural Science Foundation of China(No.42277097,41425007)the High-level Team Project of China Agricultural University,Chongqing Technology Innovation and Application Development Project(cstc2021jscx-cylh0024)the Deutsche Forschungsgeminschaft(DFG)-328017493/GRK 2366(No.Sino-German IRTG AMAIZE-P)。
文摘Atmospheric nitrogen(N)deposition has experienced significant change because of anthropogenic emissions,thereby exert-ing a pronounced impact on global ecosystem services.With the rapid development of industry and agriculture and the swift expansion of urban areas in China since the 1980s,reactive nitrogen(Nr)emissions and N deposition have substantially increased.In pursuit of im-proving air quality,China has implemented a series of environmental protection policies and undertaken diverse measures to reduce pol-lutant emissions.This paper is a review of multivariate data sources of atmospheric N deposition based on the results of literature from 1980 to 2023,and the original data from 1980 to 2020 are summarized,counted and calculated.The main findings are as follows:1)the annual average atmospheric N deposition ranged from approximately 20-40 kg/(ha·yr),with the variability primarily linked to different assessment methods;2)regional disparities were evident in the spatial distribution of N deposition,with elevated values concentrated in areas with intense Nr emissions;3)atmospheric N deposition significantly declined after 2010,particularly the deposition of oxidized N,while reduced N deposition remained stable.These results reflect the effects of China's serious control policies on nitrogen oxide(NO.)emissions and strengthen the importance of agricultural NH3 emission mitigation.This study contributes to a comprehensive understand-ing of the N dynamics in the emission-deposition process,and provides a scientific foundation for the research of environmental protec-tion,climate change,and sustainable development.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42000000)the Key Program of National Natural Science Foundation of China(No.41930533)+1 种基金the Chinese Academy of Sciences Pioneer Hundred Talents Program(to Nansheng CHEN)the Taishan Scholar Project Special Fund(to Nansheng CHEN)。
文摘One specimen belonging to the family Comatellinae was collected from the Zhenbei Seamount(332.5–478.2 m)in the South China Sea in July 2022.Based on the morphological characters,the specimen was identified as Palaeocomatella hiwia McKnight,1977.It is first recorded from China Sea and redescribed in detail.This specimen differs from the original description from New Zealand for never showing syzygy at br4+5 or br5+6 on interior and br1+2 on exterior arms.However,it is much conform to the redescription to specimens from Indonesia,with only differences in position of the second syzygy and distalmost pinnule comb.Specimen is deposited in the Institute of Oceanology,Chinese Academy of Sciences.Phylogenetic analyses based on the mitochondrial c oxidase subunit I(COI)and 16S rRNA genes indicated that P.hiwia was nested within the tribe Phanogeniini and clustered with Aphanocomaster pulcher.Furthermore,P.hiwia showed same morphological features in terms of mouth placement,comb location,and number of comb teeth rows as other genera of Phanogeniini.Therefore,we suggest that the genus Palaeocomatella should be put in the tribe Phanogeniini.
文摘Background: The Air Force Health Study collected reproductive outcomes for live-born children of male Air Force veterans of the Vietnam War. Methods: Dioxin values for participants were obtained from blood samples. Analyses were conducted of occurrence of 16 specific categories of birth defects and developmental disabilities. Children were categorized as conceived before and after the start of participants’ Vietnam War service. Children conceived before the start of Vietnam War service were treated as being conceived when their fathers had unquantifiable dioxin values. Children conceived after the start of Vietnam War service for participants with missing dioxin values were excluded from primary analyses, but were used to assess the impact of their exclusion on conclusions. Correlation between values for specific categories for multiple children fathered by the same participant was accounted for. The dose-response relationship was treated as a step function increasing for dioxin values larger than adaptively identified individual thresholds changing with the specific category. Results: For 15 of 16 specific categories, the probability of occurrence increased substantially for a sufficiently high dioxin level above identified thresholds. Exclusion of children due to missing dioxin likely did not affect these results. Conclusions: Results supported the conclusion of substantial adverse effects on a wide variety of specific categories of birth defects and developmental disabilities due to sufficiently high exposures to dioxin, a toxic contaminant of Agent Orange used for herbicide spraying in the Vietnam War. Results may hold more generally, but might also have been affected by a variety of limitations.
基金Supported by National Natural Science Foundation of China (40775048)Major State Basic Research Development Program (2006CB400504)National Key Technology R & D Program (2007BAC294)
文摘By means of ERA-40, JRA-25, NCEP/NCAR and NCEP/DOE reanalysis data, empirical relations between precipitable water and surface vapor pressure in spatial and temporal scale were calculated. The reliabilities of precipitable water from reanalysis data were validated based on comparing different W-e empirical relations of various reanalysis data, in order to provide basis and reference for reasonable application. The results showed that W-e empirical relation of ERA-40 was closest to that of sounding data in China, and precipitable water from ERA-40 was the most credible. The worldwide comparison among W-e empirical relations of four reanalysis data showed that there was little difference in annual mean W-e empirical relations in the middle latitudes and great differences in low and high latitudes. Seasonal mean W-e empirical relations in the middle latitudes of the northern Hemisphere had little difference in spring, autumn and winter, but great difference in summer. Therefore, the reliabilities of precipitable water from reanalysis data in spring, autumn and winter in the middle latitudes of the northern hemisphere were higher than other areas and seasons. W-e empirical relations of NCEP/NCAR and NCEP/DOE had good stability in different years, while there was poor stability in ERA-40 and JRA-25.
基金China State Railway Group Co.,Ltd.has supported this work as a critical project(Grant No.:N2022Z020).
文摘Purpose-Following the regional restructuring,the number of joint-venture railway companies in which the Group participates has significantly increased.This paper aims to explore the challenges faced by China Railway Group in managing participation in joint-venture railway companies.The study seeks to propose specific approaches to ensure the effective management of these companies,thereby maximizing the benefits of the regional restructuring and supporting the development of a strong transportation country and a modern infrastructure system.Design/methodology/approach-Based on the change in the shareholding relationship between China Railway Group and the joint-venture railway companies,and considering the current situation of the regional restructuring of these companies,as well as the insights from existing literature and typical case studies,this paper proposes some specific paths for effective management of joint-stock railway companies which China Railway Group participated in.Findings-The problems in participation management are the unclear dual leadership role of the party committee,the lack of discourse power,the lack of synergy between shareholders,the increasing risk of sustainable operation of the loss-making companies and the role of dispatched personnel is not fully played.Based on the theories,combined with the existing research and practical cases,the paper proposed specific approaches,such as perfecting top-level system design,maintaining the discourse power,carrying out differentiated management,arranging personnel rationally,arranging shareholders synergy,and innovating methods to provide references for China Railway Group’s subsequent management of joint venture railway companies.Originality/value-This paper contributes to the existing literature by providing a comprehensive analysis of the challenges faced by China Railway Group in managing participation in joint-venture railway companies following the regional restructuring.The study offers novel insights and practical recommendations for addressing these challenges.The findings can serve as valuable references for China Railway Group’s subsequent management of joint-venture railway companies which participated in,as well as for other stateowned enterprises facing similar challenges in managing their joint ventures.
基金supported by the key project of the National Social Science Fund of China(NSSFC):“Study on China-Russia Strategic Partnership for the New Era”(Grant No.20AGJ012).
文摘In the post-pandemic era,the global economic and security landscapes are fraught with complexities and uncertainties.Among them,four risk flashpoints merit attention:Certain countries are raising interest rates to subdue inflation,despite their already high levels of debt;the bulk commodities market is experiencing volatility,leading to global turbulence and change;trade protectionism is at the forefront of major-power rivalry in political and economic spheres;and regional security crises are compounding international tensions.Behind those flashpoints are contradictions that obstruct world peace and progress,including development imbalances,governance gaps,and structural tensions in global security.In the face of uncertainties,it is crucial for China to seize strategic opportunities and transform crises into favorable situations.China has launched the Global Development Initiative(GDI)and the Global Security Initiative(GSI)to contribute to global prosperity and security.The two initiatives demonstrate China’s commitment to addressing global deficits in peace,development,security,and governance.
文摘The orderly transfer of the manufacturing industry is a major action in China’s industrial restructuring.From the perspective of industrial transfer,we used the concentration ratio to depict the trend of the industrial transfer of energy-intensive manufacturing in the eastern,central,and western regions since the policy of large-scale development of western China was implemented.We measured the total factor productivity(TFP)of western China using the DEAMalmquist index method.We conducted a regression analysis to measure the effect of western China’s undertaking of the transfer of the energy-intensive manufacturing industry.The findings of this study show that during 2000–2019,eleven provinces(as well as autonomous regions and municipalities)in western China undertook the transfer of the energy-intensive manufacturing industry from the eastern and central regions to varying degrees,exhibiting significant phase features regarding the rate and scale of transfers.Further investigation also demonstrated that the transfer of energy-intensive manufacturing industries has a U-shaped enabling effect on TFP in western China with the scale effect greater than the technology effect.Therefore,it is necessary to transition from“extensive industrial transfer”at the cost of the labor force,land,and resources to“modern industrial transfer”featured by technology and efficiency improvements to contribute to industrial restructuring in western China effectively.