Traditionally,numerical trajectory integration for shooting equation calculation and iterations for shooting with randomly guessed initial solutions deteriorate the real-time performance of indirect methods for on-boa...Traditionally,numerical trajectory integration for shooting equation calculation and iterations for shooting with randomly guessed initial solutions deteriorate the real-time performance of indirect methods for on-board applications.In this study,the indirect method is improved to achieve real-time trajectory optimization of fuel-optimal powered planetary landings with the help of analytical shooting equation derivations and a practical homotopy technique.Specifically,the contributions of this paper are threefold.First,the analytical expressions for shooting equation calculation are derived to replace the traditional time-consuming trajectory integration.Consequently,the computational efficiency is significantly improved.Second,the original three-dimensional landing problem is connected with a simplified one-dimensional problem that only involves the vertical dynamics,and its analytical solution is obtained based on Pontryagin’s minimum principle.Third,starting with the analytical solution,the accurate solution of the original landing problem can be obtained through an adaptive homotopy process.Simulation results of Earth landing scenarios are given to substantiate the effectiveness of the proposed techniques and illustrate that the developed method can obtain a fuel-optimal landing trajectory in 5 ms with 100%success rate.展开更多
Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on es...Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on estimates of the mean trophic index （MTI） and Fishing in Balance index （FIB）, and on landing profile of the exploited marine community （49 species） during the period, 2002-2011. The total landings （Yt） （R=0.88, P〈0.001） increased gradually while the Y~ of carnivores has slightly declined, and the Yt of herbivores, detritivores and omnivores has increased. Consequently, the MTI significantly decreased （R=-0.69, P〈0.05） at a rate of 0.1 l during this decade. The MTI showed a decreasing trend, which indicates exploitation of marine resources. The FiB index also showed a downward trend and negative values from 2002 to 2009, which may be associated with unbalanced structure in the fisheries, but an upward trend from 2009 to 20ll. The time variation of the landing profile showed two periods with significant differences in their species composition （R=0.88; P=0.005）, and based on analysis of similarity, species have been identified as discriminator species, namely Thunnus albacores and Benthosema pterotum. Results indicate that changes in MTI reflected changes in the Hormuzgan landing structure. The examination of the MTI, FBI, and landing profile （LP） temporal pattern suggests that the status of fishery resources in Hormuzgan inshore waters is overexploited, and provides evidence of the probability that a fishing down process is occurring in this area, and that this trend may continue in the long-tenn. Therefore, environmental fisheries management and conservation programs should be prioritized for these valuable resources.展开更多
Purpose:To determine the effect of unanticipated mid-flight medial-lateral external perturbation of the upper or lower trunk on anterior cruciate ligament(ACL)loading variable s during jump-landings.Methods:Thirty-two...Purpose:To determine the effect of unanticipated mid-flight medial-lateral external perturbation of the upper or lower trunk on anterior cruciate ligament(ACL)loading variable s during jump-landings.Methods:Thirty-two participants performed double-leg vertical jump-landings while bilateral kinematics and kinetics were collected under 6conditions(upper or lower trunk perturbation locations;no,left,or right perturbation directions).Two customized catapult apparatuses were created to apply pushing perturbation to participants near the maximal jump height.Results:The ball contacted participants near the center of mass for the lower-trunk conditions and approximately 23 cm above the center of mass for the upper-trunk conditions.Under upper-trunk perturbation,the contralateral leg demonstrated significantly smaller knee flexion angles at initial contact and greater peak knee abduction angles,peak vertical ground reaction forces,peak knee extension moments,and peak knee adduction moments compared to other legs among all conditions.Under lower-trunk perturbation,the contralateral leg showed significantly smaller knee flexion angles at initial contact and increased peak vertical ground reaction forces and peak knee extension moments compared to legs in the no-perturbation conditions.Conclusion:Mid-flight external trunk pushing perturbation increased ACL loading variables for the leg contralateral to the perturbation.The uppertrunk perturbation resulted in greater changes in ACL loading variables compared to the lower-trunk perturbation,likely due to trunk and ipsilateral leg rotation and more laterally located center of mass relative to the contralateral leg.These findings may help us understand the mechanisms of indirect-contact ACL injuries and develop jump-landing training strategies under mid-flight trunk perturbation to better prevent ACL injury.展开更多
This investigation focuses on two mechanisms over the North Pacific connecting decadal regime shifts to regional ecosystem impacts. The physical conditions show the impacts of the atmospheric surface wind stress and t...This investigation focuses on two mechanisms over the North Pacific connecting decadal regime shifts to regional ecosystem impacts. The physical conditions show the impacts of the atmospheric surface wind stress and the sea surface temperature (SST) physical conditions on the fish landings along the west coast of California (WCC) from 1928-2008. The two mechanisms are identified by the two types of wind stress (e.g. westerly-easterly;or cyclonic-anticyclonic) anomaly over the central North Pacific which results in SST anomalies in the WCC. In both mechanism cases, the local warm (cold) SST anomaly leads to the number of fish species rising (falling) in the WCC region. In addition, the wind stress and SST anomaly pattern over the North Pacific is closely related to the intensity of the regime shifts as identified in the fish landings off the WCC.展开更多
英国作家立德夫人的民族志作品The Land of the Blue Gown有多个汉语无本回译译本。本文选取其中三个代表性译本,尝试从民族志翻译理论出发,通过对不同译本的语言风格传达和文化信息还原进行比较,总结各无本回译译本的翻译策略选择以及...英国作家立德夫人的民族志作品The Land of the Blue Gown有多个汉语无本回译译本。本文选取其中三个代表性译本,尝试从民族志翻译理论出发,通过对不同译本的语言风格传达和文化信息还原进行比较,总结各无本回译译本的翻译策略选择以及译者在各自翻译过程中扮演的不同角色,为民族志翻译相关研究作学理探讨。展开更多
The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is av...The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is available on how the rainfall affect nutrient dynamics in subtropicalmontane rivers with complex land use.This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu,a montane reservoir of southeast China.The results showed that riverine total nitrogen(TN)and total phosphorus(TP)concentrations increased continuously with increasing rainfall intensity,while TN:TP decreased.The heavy rainfall and rainstorm drove more than 30%of the annual N and P loading in only 5.20%of the total rainfall period,indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs.NO_(3)^(−)-N is the primary nitrogen form lost,while particulate phosphorus(PP)dominated phosphorus loss.Themain source of N is cropland,and themain source of P is residential area.Spatially,forestedwatersheds have better drainage quality,while it is still a potential source of nonpoint pollution during rainfall events.TN and TP concentrations were significantly higher at sites dominated by cropland and residential area,indicating their substantial contributions to deteriorating river water quality.Temporally,TN and TP concentrations reached high values in May-August when rainfall was most intense,while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities.The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads,providing guidance for nutrient load reduction planning for Lake Qiandaohu.展开更多
Land use transformations in Sonipat District,Haryana,driven by urbanization,industrialization,and land acquisitions,have posed significant ecological and socio-economic challenges,particularly concerning food security...Land use transformations in Sonipat District,Haryana,driven by urbanization,industrialization,and land acquisitions,have posed significant ecological and socio-economic challenges,particularly concerning food security.This study investigates the interplay between these land use changes and their environmental implications at macro(district)and micro(village)levels,focusing on agricultural productivity and resource sustainability.The study employs a mixed-method approach,integrating secondary data from official datasets and primary data gathered through structured household surveys,focus group discussions,and visual analysis techniques.Data from 20 villages,selected based on predominant land use characteristics,were analysed using statistical and geospatial tools,including ArcGIS and STATA,to quantify food grain losses and evaluate environmental degradation.Findings of this study reveal a 19%reduction in agricultural land over two decades(2000-2024),correlating with increased residential and industrial areas.Groundwater resources face severe overexploitation,with pollution from industrial clusters further degrading water and soil quality.The study estimates a total food grain loss of 1.5 million kilograms across surveyed villages due to land acquisitions.A strong positive correlation(R^(2)=0.98)between land acquisition and food loss underscores the direct impact of urbanization on agricultural output.The research underscores the urgency of sustainable land management practices,including preserving agricultural lands,optimizing groundwater usage,and enhancing community involvement in planning.By addressing these challenges,the study advocates for balanced urban expansion and food security to ensure ecological and economic resilience in the region.展开更多
1.Introduction Changes in land use are key factors promoting global climate change,and the side effects of mining activity that destroy the soil,vegetation,and biodiversity lead to imbalanced carbon cycling in terrest...1.Introduction Changes in land use are key factors promoting global climate change,and the side effects of mining activity that destroy the soil,vegetation,and biodiversity lead to imbalanced carbon cycling in terrestrial ecosystems.展开更多
Northern China is a prominent “hotspot” for land–atmosphere interactions, with substantial gradients in both moisture and thermal conditions. Previous studies have identified a link between land–atmosphere couplin...Northern China is a prominent “hotspot” for land–atmosphere interactions, with substantial gradients in both moisture and thermal conditions. Previous studies have identified a link between land–atmosphere coupling and the individual roles of each factor, but the synergistic effect of the two factors remains unclear. This study considers the covariation of evapotranspiration and precipitation to assess evapotranspiration–precipitation(ET–P) coupling across northern China,exploring its spatial variations and their linkage to water and heat factors. Our findings reveal a transition from strongly positive coupling in the northwest to weakly negative coupling in the southeast, peaking in spring. These spatial variations are attributable to water(soil moisture) and heat(air temperature), which explain 39% and 25% of the variability,respectively. The aridity index(AI), a water–heat synergy factor, is the dominant factor, explaining 66% of the spatial variation in ET–P coupling. As the AI increases, ET–P coupling shifts from strongly positive to weakly negative, with an AI around 0.7. This shift is determined by a shift in the evapotranspiration–lifting condensation level(LCL) coupling under an AI change. Regions with an AI below 0.7 experience water-limited evapotranspiration, where increased soil moisture enhances evapotranspiration, reduces sensible heat(H), and lowers the LCL, resulting in a negative ET–LCL coupling.Conversely, regions with an AI above 0.7 experience energy-limited evapotranspiration, where the positive ET–LCL coupling reflects a positive H–LCL coupling or a positive impact of the LCL on evapotranspiration. This analysis advances our understanding of the intricate influences of multifactor surface interactions on the spatial variations of land–atmosphere coupling.展开更多
Accurate spatio-temporal land cover information in agricultural irrigation districts is crucial for effective agricultural management and crop production.Therefore,a spectralphenological-based land cover classificatio...Accurate spatio-temporal land cover information in agricultural irrigation districts is crucial for effective agricultural management and crop production.Therefore,a spectralphenological-based land cover classification(SPLC)method combined with a fusion model(flexible spatiotemporal data fusion,FSDAF)(abbreviated as SPLC-F)was proposed to map multi-year land cover and crop type(LC-CT)distribution in agricultural irrigated areas with complex landscapes and cropping system,using time series optical images(Landsat and MODIS).The SPLC-F method was well validated and applied in a super-large irrigated area(Hetao)of the upper Yellow River Basin(YRB).Results showed that the SPLC-F method had a satisfactory performance in producing long-term LC-CT maps in Hetao,without the requirement of field sampling.Then,the spatio-temporal variation and the driving factors of the cropping systems were further analyzed with the aid of detailed household surveys and statistics.We clarified that irrigation and salinity conditions were the main factors that had impacts on crop spatial distribution in the upper YRB.Investment costs,market demand,and crop price are the main driving factors in determining the temporal variations in cropping distribution.Overall,this study provided essential multi-year LC-CT maps for sustainable management of agriculture,eco-environments,and food security in the upper YRB.展开更多
Foreign-funded overseas industrial parks(OIPs)are crucial for attracting foreign investment and promoting globalization in developing countries.However,large-scale land acquisition for these parks generates conflicts ...Foreign-funded overseas industrial parks(OIPs)are crucial for attracting foreign investment and promoting globalization in developing countries.However,large-scale land acquisition for these parks generates conflicts between developers and local stakeholders,increasing development costs.A qualitative multicase study was conducted in this study to analyze the land transaction trajectories of China's OIPs.Four OIPs were selected to reveal the underlying mechanisms from the perspectives of institutional arrangements,governance mechanisms,and enterprise heterogeneity.The findings indicate that in host countries with insufficient institutional development,local governments are more inclined to directly engage in OIP land acquisition.High-level intergovernmental mechanisms facilitate land acquisition processes,although their efficacy depends largely on administrative power allocation across parks in host countries.The results also indicate that enterprise characteristics significantly influence land acquisition,where microscale private enterprises lacking political connections often employ low-cost,bottom-up strategies by leveraging international experience.In summary,policy-makers in developing countries should prioritize enhancing OIP governance to mitigate transaction costs,promote diversified land supply,and optimize land allocation.By depicting China's OIP land acquisition processes,this study deepens the academic understanding of OIP governance in developing countries and related international land transactions,offering practical OIP management insights for governments in both host and parent countries.展开更多
Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimila...Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimilation is quite challenging.This is because there is limited knowledge about the cross-component background error covariance(BEC)between LST and atmospheric state variables.This study aims to clarify whether there is a relationship between the error of LST and atmospheric variables,and whether this relationship varies spatially and temporally.To this end,the BEC coupled with atmospheric variables and LST was constructed(LST-BEC),and its characteristics were analyzed based on the 2023 mei-yu season.The general characteristics of LST-BEC show that the LST is mainly correlated with the atmospheric temperature and the correlation decreases gradually with a rise in atmospheric height,and the error standard deviation of the LST is noticeably larger than that of the low-level atmospheric temperature.The spatiotemporal characteristics of LST-BEC on the heavy-rain day and light-rain day show that the error correlation and error standard deviation of LST and low-level atmospheric temperature and humidity are closely related to the weather background,and also have obvious diurnal variations.These results provide valuable information for strongly coupled land-atmosphere assimilation.展开更多
The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,c...The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,causing carbon storage exchanges.However,the relationship between carbon storage and land use change in the MRYR is not concerned,which results in the uncertainty in the simulation of carbon storage in this area.Land use changes directly affect the carbon storage capacity of ecosystems,and as an indicator reflecting the overall state of land use,land use degree has an important relationship with carbon storage.In this study,land use data and the integrated valuation of ecosystem services and trade-offs(InVEST)model were used to assess the trends in land use degree and carbon storage in the MRYR during 1980-2020.The potential impact index and the standard deviation ellipse(SDE)algorithm were applied to quantify and analyze the characteristics of the impact of land use changes on carbon storage.Subsequently,land use transitions that led to carbon storage variations and their spatial variations were determined.The results showed that:(1)the most significant periods of carbon storage changes and land use transitions were observed during 1990-1995 and 1995-2020,with the most changed areas locating in the east of Fenhe River and in northwestern Henan Province;(2)the positive impact of land use degree on carbon storage may be related to the environmental protection measures implemented along the Yellow River,while the negative impact may be associated with the expansion of construction land in plain areas;and(3)the conversion of other land use types to grassland was the primary factor affecting carbon storage changes during 1980-2020.In future land use planning,attention should be given to the direction of grassland conversion,and focus on reasonably limiting the development of construction land.To enhance carbon storage,it will be crucial to increase the area of high-carbon-density land types,such as forest land and grassland under the condition that the area of permanent farmland does not decrease.展开更多
Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and t...Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.展开更多
Clarifying the mechanisms through which coal mining affects groundwater storage(GWS)variations is crucial for water resource conservation and sustainable development.The Ordos Mining Region in China,a key energy base ...Clarifying the mechanisms through which coal mining affects groundwater storage(GWS)variations is crucial for water resource conservation and sustainable development.The Ordos Mining Region in China,a key energy base in China with significant strategic importance,has undergone intensive coal mining activities that have substantially disrupted regional groundwater circulation.This study integrated data from the Gravity Recovery and Climate Experiment Satellite(GRACE)and Famine Early Warning Systems Network(FEWS NET)Land Data Assimilation System(FLDAS)models,combined with weighted downscaling methodology and water balance principles,to reconstruct high-resolution(0.01°)terrestrial water storage(TWS)and GWS changes in the Ordos Mining Region,China from April 2002 to December 2021.The accuracy of GWS variations were validated through pumping test measurements.Subsequently,Geodetector analysis was implemented to quantify the contributions of natural and anthropogenic factors to groundwater storage dynamics.Key findings include:1)TWS in the study area showed a fluctuating but overall decreasing trend,with a total reduction of 8901.11 mm during study period.The most significant annual decrease occurred in 2021,reaching 1696.77 mm.2)GWS exhibited an accelerated decline,with an average annual change rate of 44.35 mm/yr,totaling a decrease of 887.05 mm.The lowest annual groundwater storage level was recorded in 2020,reaching 185.69 mm.3)Precipitation(PRE)contributed the most to GWS variation(q=0.52),followed by coal mining water consumption(MWS)(q=0.41).The interaction between PRE and MWS exhibited a nonlinear enhancement effect on GWS changes(0.54).The synergistic effect of natural hydrological factors has a great influence on the change of GWS,but coal mining water consumption will continue to reduce GWS.These findings provide critical references for the management and regulation of groundwater resource in mining regions.展开更多
0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly ...0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly prominent.China has implemented and completed several largescale land infilling and excavation projects(Figure 1),which have become the main way to increase land resources and expand construction land.展开更多
Human-wildlife conflict(HWC)and its socioeconomic impacts are a pressing global issue.Accurately quantifying HWCs and their interaction with residential development is crucial for rural revitalization and biodiversity...Human-wildlife conflict(HWC)and its socioeconomic impacts are a pressing global issue.Accurately quantifying HWCs and their interaction with residential development is crucial for rural revitalization and biodiversity conservation efforts.This study investigates the interplay between rural residential expansion(RRE)with humanelephant conflict(HEC)in southern Yunnan Province using high-accuracy yearly land use/land cover data and Asian elephant accident data.A piecewise regression along with several metrics,including expansion intensity,rate of rural residential land,and residential density,were employed to analyze the spatial-temporal change characteristics of RRE.Then,a geographical detector and a bivariate spatial autocorrelation model were used to reveal the driving mechanisms of RRE,with particular emphasis on the spatial relations between RRE and HECs.The results indicate that HECs had a significant negative impact on RRE,exhibiting higher expansion intensity and rate of rural residential land in non-HEC areas than in HEC areas.High spatiotemporal consistency between accelerated RRE and intensified HECs occurred from 2010 onwards,which aligns with the year when the trend of settlement area expansion changed.RRE activities and ensuing land use conversions led to increased occurrences of HECs,which negatively affected the RRE.Compared to HECs,topography and locational factors exhibited a secondary effect on RRE activities.The findings underscore reciprocal feedback mechanisms between RRE and HECs and the elevated risk of adverse interactions between humans and elephants within the range of China’s wild elephants,providing theoretical support for coordinating conservation initiatives for Asian elephants with rural revitalization in the border areas of Southwest China.展开更多
The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.Thi...The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.This study assessed the land subsidence before and after urban expansion in five areas of Lanzhou by using slope spectrum construction method and gradient expansion intensity measurement that integrated with SBAS-InSAR technology.The results show that construction land on slopes over 20°increased significantly,accounting for 16%of new construction land.The average slope spectrum index was 4.02,with the upper slope limit rising by 8.2°.The land subsidence rate threshold increased by 10 mm/a,and the proportion of pixels experiencing subsidence greater than 5 mm/year rose from 3.63%to 5.24%.Increased construction intensity on slopes caused higher and faster subsidence,which diminished with greater distance from the expansion areas.Areas with slopes between 10°and 25°saw the greatest acceleration in subsidence.Geological composition,building density,groundwater exploitation,and cut-and-fill thickness collectively influence land subsidence rates.This study provides a scientific basis for mitigating geological disaster risks and promoting safe urban development in mountainous cities.展开更多
Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological component...Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological components of these watersheds has been altered by human activities,which directly impacts them through changes in land use.In Colombia,the lack of control over land-use in watersheds has affected the water regulation services of important tributaries,such as the Onzaga River,whose waters are mainly used for agricultural activities.For this reason,this study aims to evaluate how changes in land use in the basin affected the capacity of water regulation.For this,a statistical correlation analysis was conducted between the Water Regulation Index(WRI)and vegetation cover areas from 1985 to 2023.The study results indicate that the expansion of the anthropogenic vegetation covers,such as agriculture parches and grasslands,replacing different types of forests,and producing an adverse effect on the water regulation capacity for the basin.This demonstrated its decrease along with an increase in its variability,indicating that,in addition to its degradation,there is a greater irregularity in this ecosystem service.In conclusion,correlation analysis indicates that 93%of the change in water regulation regime is explained by the contraction of forest cover and the expansion of agricultural areas,degraded lands,and urban development.This study confirms the importance of preserving native vegetation cover in the watershed,especially in areas adjacent to watercourses with riparian forests.展开更多
China Completes First Manned Lunar Lander Landing and Takeoff Test China announced that it has successfully completed a comprehensive landing and takeoff test on August 7 for its manned lunar lander at a test site in ...China Completes First Manned Lunar Lander Landing and Takeoff Test China announced that it has successfully completed a comprehensive landing and takeoff test on August 7 for its manned lunar lander at a test site in Huailai County,north China's Hebei Province.The test which was completed on August 6 represents a key step in the development of China’s manned lunar exploration program,and also marks the first time that China has carried out a test of extraterrestrial landing and takeoff capabilities of a manned spacecraft,the China Manned Space Agency said.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11872223,11902174,11772167)。
文摘Traditionally,numerical trajectory integration for shooting equation calculation and iterations for shooting with randomly guessed initial solutions deteriorate the real-time performance of indirect methods for on-board applications.In this study,the indirect method is improved to achieve real-time trajectory optimization of fuel-optimal powered planetary landings with the help of analytical shooting equation derivations and a practical homotopy technique.Specifically,the contributions of this paper are threefold.First,the analytical expressions for shooting equation calculation are derived to replace the traditional time-consuming trajectory integration.Consequently,the computational efficiency is significantly improved.Second,the original three-dimensional landing problem is connected with a simplified one-dimensional problem that only involves the vertical dynamics,and its analytical solution is obtained based on Pontryagin’s minimum principle.Third,starting with the analytical solution,the accurate solution of the original landing problem can be obtained through an adaptive homotopy process.Simulation results of Earth landing scenarios are given to substantiate the effectiveness of the proposed techniques and illustrate that the developed method can obtain a fuel-optimal landing trajectory in 5 ms with 100%success rate.
文摘Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on estimates of the mean trophic index （MTI） and Fishing in Balance index （FIB）, and on landing profile of the exploited marine community （49 species） during the period, 2002-2011. The total landings （Yt） （R=0.88, P〈0.001） increased gradually while the Y~ of carnivores has slightly declined, and the Yt of herbivores, detritivores and omnivores has increased. Consequently, the MTI significantly decreased （R=-0.69, P〈0.05） at a rate of 0.1 l during this decade. The MTI showed a decreasing trend, which indicates exploitation of marine resources. The FiB index also showed a downward trend and negative values from 2002 to 2009, which may be associated with unbalanced structure in the fisheries, but an upward trend from 2009 to 20ll. The time variation of the landing profile showed two periods with significant differences in their species composition （R=0.88; P=0.005）, and based on analysis of similarity, species have been identified as discriminator species, namely Thunnus albacores and Benthosema pterotum. Results indicate that changes in MTI reflected changes in the Hormuzgan landing structure. The examination of the MTI, FBI, and landing profile （LP） temporal pattern suggests that the status of fishery resources in Hormuzgan inshore waters is overexploited, and provides evidence of the probability that a fishing down process is occurring in this area, and that this trend may continue in the long-tenn. Therefore, environmental fisheries management and conservation programs should be prioritized for these valuable resources.
基金supported by the National Science Foundation(1933409)the China Scholarship Council+1 种基金a student research grant from the International Society of Biomechanics in Sportsthe Wyoming IDeA Networks for Biomedical Research Excellence,supported by the National Institutes of Health(P20GM103432)。
文摘Purpose:To determine the effect of unanticipated mid-flight medial-lateral external perturbation of the upper or lower trunk on anterior cruciate ligament(ACL)loading variable s during jump-landings.Methods:Thirty-two participants performed double-leg vertical jump-landings while bilateral kinematics and kinetics were collected under 6conditions(upper or lower trunk perturbation locations;no,left,or right perturbation directions).Two customized catapult apparatuses were created to apply pushing perturbation to participants near the maximal jump height.Results:The ball contacted participants near the center of mass for the lower-trunk conditions and approximately 23 cm above the center of mass for the upper-trunk conditions.Under upper-trunk perturbation,the contralateral leg demonstrated significantly smaller knee flexion angles at initial contact and greater peak knee abduction angles,peak vertical ground reaction forces,peak knee extension moments,and peak knee adduction moments compared to other legs among all conditions.Under lower-trunk perturbation,the contralateral leg showed significantly smaller knee flexion angles at initial contact and increased peak vertical ground reaction forces and peak knee extension moments compared to legs in the no-perturbation conditions.Conclusion:Mid-flight external trunk pushing perturbation increased ACL loading variables for the leg contralateral to the perturbation.The uppertrunk perturbation resulted in greater changes in ACL loading variables compared to the lower-trunk perturbation,likely due to trunk and ipsilateral leg rotation and more laterally located center of mass relative to the contralateral leg.These findings may help us understand the mechanisms of indirect-contact ACL injuries and develop jump-landing training strategies under mid-flight trunk perturbation to better prevent ACL injury.
文摘This investigation focuses on two mechanisms over the North Pacific connecting decadal regime shifts to regional ecosystem impacts. The physical conditions show the impacts of the atmospheric surface wind stress and the sea surface temperature (SST) physical conditions on the fish landings along the west coast of California (WCC) from 1928-2008. The two mechanisms are identified by the two types of wind stress (e.g. westerly-easterly;or cyclonic-anticyclonic) anomaly over the central North Pacific which results in SST anomalies in the WCC. In both mechanism cases, the local warm (cold) SST anomaly leads to the number of fish species rising (falling) in the WCC region. In addition, the wind stress and SST anomaly pattern over the North Pacific is closely related to the intensity of the regime shifts as identified in the fish landings off the WCC.
文摘英国作家立德夫人的民族志作品The Land of the Blue Gown有多个汉语无本回译译本。本文选取其中三个代表性译本,尝试从民族志翻译理论出发,通过对不同译本的语言风格传达和文化信息还原进行比较,总结各无本回译译本的翻译策略选择以及译者在各自翻译过程中扮演的不同角色,为民族志翻译相关研究作学理探讨。
基金supported by the National Natural Science Foundation of China(Nos.U2340209,and 42271126)the NIGLAS Foundation(No.NIGLAS2022GS03)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20220041)the US National Science Foundation Projects(Nos.1831096,1803697,and 2108917).
文摘The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is available on how the rainfall affect nutrient dynamics in subtropicalmontane rivers with complex land use.This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu,a montane reservoir of southeast China.The results showed that riverine total nitrogen(TN)and total phosphorus(TP)concentrations increased continuously with increasing rainfall intensity,while TN:TP decreased.The heavy rainfall and rainstorm drove more than 30%of the annual N and P loading in only 5.20%of the total rainfall period,indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs.NO_(3)^(−)-N is the primary nitrogen form lost,while particulate phosphorus(PP)dominated phosphorus loss.Themain source of N is cropland,and themain source of P is residential area.Spatially,forestedwatersheds have better drainage quality,while it is still a potential source of nonpoint pollution during rainfall events.TN and TP concentrations were significantly higher at sites dominated by cropland and residential area,indicating their substantial contributions to deteriorating river water quality.Temporally,TN and TP concentrations reached high values in May-August when rainfall was most intense,while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities.The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads,providing guidance for nutrient load reduction planning for Lake Qiandaohu.
文摘Land use transformations in Sonipat District,Haryana,driven by urbanization,industrialization,and land acquisitions,have posed significant ecological and socio-economic challenges,particularly concerning food security.This study investigates the interplay between these land use changes and their environmental implications at macro(district)and micro(village)levels,focusing on agricultural productivity and resource sustainability.The study employs a mixed-method approach,integrating secondary data from official datasets and primary data gathered through structured household surveys,focus group discussions,and visual analysis techniques.Data from 20 villages,selected based on predominant land use characteristics,were analysed using statistical and geospatial tools,including ArcGIS and STATA,to quantify food grain losses and evaluate environmental degradation.Findings of this study reveal a 19%reduction in agricultural land over two decades(2000-2024),correlating with increased residential and industrial areas.Groundwater resources face severe overexploitation,with pollution from industrial clusters further degrading water and soil quality.The study estimates a total food grain loss of 1.5 million kilograms across surveyed villages due to land acquisitions.A strong positive correlation(R^(2)=0.98)between land acquisition and food loss underscores the direct impact of urbanization on agricultural output.The research underscores the urgency of sustainable land management practices,including preserving agricultural lands,optimizing groundwater usage,and enhancing community involvement in planning.By addressing these challenges,the study advocates for balanced urban expansion and food security to ensure ecological and economic resilience in the region.
基金supported by the National Natural Science Foun dation of China(52374170 and 51974313)the National Key Research and Development Plan Project(2022YFF1303300).
文摘1.Introduction Changes in land use are key factors promoting global climate change,and the side effects of mining activity that destroy the soil,vegetation,and biodiversity lead to imbalanced carbon cycling in terrestrial ecosystems.
基金jointly supported by the National Science Foundation of China (Grant No.42230611)the Meteorological Joint Fund (Grant No.U2142208)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (grant no.2019QZKK0102)the National Science Foundation of China (Grant No.42005071)the Gansu Province Key Talent Project (Grant No.2023RCXM37)。
文摘Northern China is a prominent “hotspot” for land–atmosphere interactions, with substantial gradients in both moisture and thermal conditions. Previous studies have identified a link between land–atmosphere coupling and the individual roles of each factor, but the synergistic effect of the two factors remains unclear. This study considers the covariation of evapotranspiration and precipitation to assess evapotranspiration–precipitation(ET–P) coupling across northern China,exploring its spatial variations and their linkage to water and heat factors. Our findings reveal a transition from strongly positive coupling in the northwest to weakly negative coupling in the southeast, peaking in spring. These spatial variations are attributable to water(soil moisture) and heat(air temperature), which explain 39% and 25% of the variability,respectively. The aridity index(AI), a water–heat synergy factor, is the dominant factor, explaining 66% of the spatial variation in ET–P coupling. As the AI increases, ET–P coupling shifts from strongly positive to weakly negative, with an AI around 0.7. This shift is determined by a shift in the evapotranspiration–lifting condensation level(LCL) coupling under an AI change. Regions with an AI below 0.7 experience water-limited evapotranspiration, where increased soil moisture enhances evapotranspiration, reduces sensible heat(H), and lowers the LCL, resulting in a negative ET–LCL coupling.Conversely, regions with an AI above 0.7 experience energy-limited evapotranspiration, where the positive ET–LCL coupling reflects a positive H–LCL coupling or a positive impact of the LCL on evapotranspiration. This analysis advances our understanding of the intricate influences of multifactor surface interactions on the spatial variations of land–atmosphere coupling.
基金National Natural Science Foundation of China,No.52379053,No.52022108The Key Research Project of Science and Technology in Inner Mongolia Autonomous Region of China,No.NMKJXM202208,No.NMKJXM202301The Project Funded by the Water Resources Department of Inner Mongolia Autonomous Region of China,No.NSK202103。
文摘Accurate spatio-temporal land cover information in agricultural irrigation districts is crucial for effective agricultural management and crop production.Therefore,a spectralphenological-based land cover classification(SPLC)method combined with a fusion model(flexible spatiotemporal data fusion,FSDAF)(abbreviated as SPLC-F)was proposed to map multi-year land cover and crop type(LC-CT)distribution in agricultural irrigated areas with complex landscapes and cropping system,using time series optical images(Landsat and MODIS).The SPLC-F method was well validated and applied in a super-large irrigated area(Hetao)of the upper Yellow River Basin(YRB).Results showed that the SPLC-F method had a satisfactory performance in producing long-term LC-CT maps in Hetao,without the requirement of field sampling.Then,the spatio-temporal variation and the driving factors of the cropping systems were further analyzed with the aid of detailed household surveys and statistics.We clarified that irrigation and salinity conditions were the main factors that had impacts on crop spatial distribution in the upper YRB.Investment costs,market demand,and crop price are the main driving factors in determining the temporal variations in cropping distribution.Overall,this study provided essential multi-year LC-CT maps for sustainable management of agriculture,eco-environments,and food security in the upper YRB.
基金Philosophy and Social Science Planning Projects in Yunnan Province,No.QN202428China Postdoctoral Science Foundation,No.2024M752918。
文摘Foreign-funded overseas industrial parks(OIPs)are crucial for attracting foreign investment and promoting globalization in developing countries.However,large-scale land acquisition for these parks generates conflicts between developers and local stakeholders,increasing development costs.A qualitative multicase study was conducted in this study to analyze the land transaction trajectories of China's OIPs.Four OIPs were selected to reveal the underlying mechanisms from the perspectives of institutional arrangements,governance mechanisms,and enterprise heterogeneity.The findings indicate that in host countries with insufficient institutional development,local governments are more inclined to directly engage in OIP land acquisition.High-level intergovernmental mechanisms facilitate land acquisition processes,although their efficacy depends largely on administrative power allocation across parks in host countries.The results also indicate that enterprise characteristics significantly influence land acquisition,where microscale private enterprises lacking political connections often employ low-cost,bottom-up strategies by leveraging international experience.In summary,policy-makers in developing countries should prioritize enhancing OIP governance to mitigate transaction costs,promote diversified land supply,and optimize land allocation.By depicting China's OIP land acquisition processes,this study deepens the academic understanding of OIP governance in developing countries and related international land transactions,offering practical OIP management insights for governments in both host and parent countries.
基金sponsored by the National Natural Science Foundation of China[grant number U2442218]。
文摘Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimilation is quite challenging.This is because there is limited knowledge about the cross-component background error covariance(BEC)between LST and atmospheric state variables.This study aims to clarify whether there is a relationship between the error of LST and atmospheric variables,and whether this relationship varies spatially and temporally.To this end,the BEC coupled with atmospheric variables and LST was constructed(LST-BEC),and its characteristics were analyzed based on the 2023 mei-yu season.The general characteristics of LST-BEC show that the LST is mainly correlated with the atmospheric temperature and the correlation decreases gradually with a rise in atmospheric height,and the error standard deviation of the LST is noticeably larger than that of the low-level atmospheric temperature.The spatiotemporal characteristics of LST-BEC on the heavy-rain day and light-rain day show that the error correlation and error standard deviation of LST and low-level atmospheric temperature and humidity are closely related to the weather background,and also have obvious diurnal variations.These results provide valuable information for strongly coupled land-atmosphere assimilation.
基金funded by the National Natural Science Foundation of China(52079103)the Outstanding Youth Science Fund of Xi'an University of Science and Technology(2024YQ2-02).
文摘The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,causing carbon storage exchanges.However,the relationship between carbon storage and land use change in the MRYR is not concerned,which results in the uncertainty in the simulation of carbon storage in this area.Land use changes directly affect the carbon storage capacity of ecosystems,and as an indicator reflecting the overall state of land use,land use degree has an important relationship with carbon storage.In this study,land use data and the integrated valuation of ecosystem services and trade-offs(InVEST)model were used to assess the trends in land use degree and carbon storage in the MRYR during 1980-2020.The potential impact index and the standard deviation ellipse(SDE)algorithm were applied to quantify and analyze the characteristics of the impact of land use changes on carbon storage.Subsequently,land use transitions that led to carbon storage variations and their spatial variations were determined.The results showed that:(1)the most significant periods of carbon storage changes and land use transitions were observed during 1990-1995 and 1995-2020,with the most changed areas locating in the east of Fenhe River and in northwestern Henan Province;(2)the positive impact of land use degree on carbon storage may be related to the environmental protection measures implemented along the Yellow River,while the negative impact may be associated with the expansion of construction land in plain areas;and(3)the conversion of other land use types to grassland was the primary factor affecting carbon storage changes during 1980-2020.In future land use planning,attention should be given to the direction of grassland conversion,and focus on reasonably limiting the development of construction land.To enhance carbon storage,it will be crucial to increase the area of high-carbon-density land types,such as forest land and grassland under the condition that the area of permanent farmland does not decrease.
基金supported by the Science Fund for the Gansu Provincial Natural Science Foundation Project(22JR5RA339).
文摘Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.
基金Under the National Key R&D Program Key Project(No.2021YFC3201201)National Natural Science Foundation of China(No.52360032)+2 种基金Basic Scientific Research Business Fee Project of Colleges And Universities Directly Under the Inner Mongolia Autonomous Region(No.JBYYWF2022001)Development Plan of Innovation Team of Colleges And Universities in Inner Mongolia Autonomous Region(No.NMGIRT2313)the Innovation Team of‘Grassland Talents’。
文摘Clarifying the mechanisms through which coal mining affects groundwater storage(GWS)variations is crucial for water resource conservation and sustainable development.The Ordos Mining Region in China,a key energy base in China with significant strategic importance,has undergone intensive coal mining activities that have substantially disrupted regional groundwater circulation.This study integrated data from the Gravity Recovery and Climate Experiment Satellite(GRACE)and Famine Early Warning Systems Network(FEWS NET)Land Data Assimilation System(FLDAS)models,combined with weighted downscaling methodology and water balance principles,to reconstruct high-resolution(0.01°)terrestrial water storage(TWS)and GWS changes in the Ordos Mining Region,China from April 2002 to December 2021.The accuracy of GWS variations were validated through pumping test measurements.Subsequently,Geodetector analysis was implemented to quantify the contributions of natural and anthropogenic factors to groundwater storage dynamics.Key findings include:1)TWS in the study area showed a fluctuating but overall decreasing trend,with a total reduction of 8901.11 mm during study period.The most significant annual decrease occurred in 2021,reaching 1696.77 mm.2)GWS exhibited an accelerated decline,with an average annual change rate of 44.35 mm/yr,totaling a decrease of 887.05 mm.The lowest annual groundwater storage level was recorded in 2020,reaching 185.69 mm.3)Precipitation(PRE)contributed the most to GWS variation(q=0.52),followed by coal mining water consumption(MWS)(q=0.41).The interaction between PRE and MWS exhibited a nonlinear enhancement effect on GWS changes(0.54).The synergistic effect of natural hydrological factors has a great influence on the change of GWS,but coal mining water consumption will continue to reduce GWS.These findings provide critical references for the management and regulation of groundwater resource in mining regions.
基金funded by the Key Research and Development Program of Shaanxi Province(No.2024SFYBXM-669)the National Natural Science Foundation of China(No.42271078)。
文摘0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly prominent.China has implemented and completed several largescale land infilling and excavation projects(Figure 1),which have become the main way to increase land resources and expand construction land.
基金supported by the National Natural Science Foundation of China(Grant No.41971239)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0402)+1 种基金Lancang-Mekong Cooperation Project on China-Laos Cross-border Asian Elephant Habitat Quality Assessment(Grant No.102169221100000009022)the Graduate Research Innovation Project of Yunnan University(Grant No.2021Y368).
文摘Human-wildlife conflict(HWC)and its socioeconomic impacts are a pressing global issue.Accurately quantifying HWCs and their interaction with residential development is crucial for rural revitalization and biodiversity conservation efforts.This study investigates the interplay between rural residential expansion(RRE)with humanelephant conflict(HEC)in southern Yunnan Province using high-accuracy yearly land use/land cover data and Asian elephant accident data.A piecewise regression along with several metrics,including expansion intensity,rate of rural residential land,and residential density,were employed to analyze the spatial-temporal change characteristics of RRE.Then,a geographical detector and a bivariate spatial autocorrelation model were used to reveal the driving mechanisms of RRE,with particular emphasis on the spatial relations between RRE and HECs.The results indicate that HECs had a significant negative impact on RRE,exhibiting higher expansion intensity and rate of rural residential land in non-HEC areas than in HEC areas.High spatiotemporal consistency between accelerated RRE and intensified HECs occurred from 2010 onwards,which aligns with the year when the trend of settlement area expansion changed.RRE activities and ensuing land use conversions led to increased occurrences of HECs,which negatively affected the RRE.Compared to HECs,topography and locational factors exhibited a secondary effect on RRE activities.The findings underscore reciprocal feedback mechanisms between RRE and HECs and the elevated risk of adverse interactions between humans and elephants within the range of China’s wild elephants,providing theoretical support for coordinating conservation initiatives for Asian elephants with rural revitalization in the border areas of Southwest China.
基金National Natural Science Foundation of China(Grant No.42271214)National Key R&D Program of China(Grant No.2022YFC3800700)+1 种基金Key Research Program of Gansu Province(Grant No.23ZDKA0004)Natural Science Foundation of Gansu Province(Grant No.21JR7RA281).
文摘The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.This study assessed the land subsidence before and after urban expansion in five areas of Lanzhou by using slope spectrum construction method and gradient expansion intensity measurement that integrated with SBAS-InSAR technology.The results show that construction land on slopes over 20°increased significantly,accounting for 16%of new construction land.The average slope spectrum index was 4.02,with the upper slope limit rising by 8.2°.The land subsidence rate threshold increased by 10 mm/a,and the proportion of pixels experiencing subsidence greater than 5 mm/year rose from 3.63%to 5.24%.Increased construction intensity on slopes caused higher and faster subsidence,which diminished with greater distance from the expansion areas.Areas with slopes between 10°and 25°saw the greatest acceleration in subsidence.Geological composition,building density,groundwater exploitation,and cut-and-fill thickness collectively influence land subsidence rates.This study provides a scientific basis for mitigating geological disaster risks and promoting safe urban development in mountainous cities.
基金The authors would like to thank the Vice-chancellor of Research at the Universidad Militar Nueva Granada for the opportunity to develop project INV-ING-3966.
文摘Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological components of these watersheds has been altered by human activities,which directly impacts them through changes in land use.In Colombia,the lack of control over land-use in watersheds has affected the water regulation services of important tributaries,such as the Onzaga River,whose waters are mainly used for agricultural activities.For this reason,this study aims to evaluate how changes in land use in the basin affected the capacity of water regulation.For this,a statistical correlation analysis was conducted between the Water Regulation Index(WRI)and vegetation cover areas from 1985 to 2023.The study results indicate that the expansion of the anthropogenic vegetation covers,such as agriculture parches and grasslands,replacing different types of forests,and producing an adverse effect on the water regulation capacity for the basin.This demonstrated its decrease along with an increase in its variability,indicating that,in addition to its degradation,there is a greater irregularity in this ecosystem service.In conclusion,correlation analysis indicates that 93%of the change in water regulation regime is explained by the contraction of forest cover and the expansion of agricultural areas,degraded lands,and urban development.This study confirms the importance of preserving native vegetation cover in the watershed,especially in areas adjacent to watercourses with riparian forests.
文摘China Completes First Manned Lunar Lander Landing and Takeoff Test China announced that it has successfully completed a comprehensive landing and takeoff test on August 7 for its manned lunar lander at a test site in Huailai County,north China's Hebei Province.The test which was completed on August 6 represents a key step in the development of China’s manned lunar exploration program,and also marks the first time that China has carried out a test of extraterrestrial landing and takeoff capabilities of a manned spacecraft,the China Manned Space Agency said.
