Investigation and analysis of the current status of farmers'livelihood capital and promptly discovering and solving problems in farmers'livelihood development are of great practical significance for optimizing...Investigation and analysis of the current status of farmers'livelihood capital and promptly discovering and solving problems in farmers'livelihood development are of great practical significance for optimizing farmers'livelihood strategies and enhancing farmers'livelihood sustainable development capability.Based on the framework of sustainable livelihood analysis,taking Yangshan County as an example,this paper uses field surveys,questionnaires and interviews to summarize and analyze the current status and characteristics and main problems of local farmers'livelihood capitals on the basis of the data of 628 farmer samples.It proposes countermeasures for future development of farmers'livelihoods.Implementing these strategies will be helpful for improving the livelihoods capital structure of farmers'and enhancing their sustainable development capability.展开更多
The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The...The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The most important result of the work is the revealed inverse relationship between grain yields and the temperature of the growing season:low-yielding years are associated with high temperatures and droughts,and high-yielding years are associated with lower temperatures and an optimal ratio of heat and moisture.The novelty of this study is the use of the method of hydrological and climatic calculations in identifying the nature of temperature variability and precipitation in the territory of Northern Kazakhstan for the modern period(1991–2020)compared with the base period(1961–1990).At all the studied meteorological stations,there is a tendency for the average annual temperature and the temperature of the growing season to increase:in the forest-steppe zone with an average warming intensity of 0.3–0.33℃ per decade;in the steppe zone by 0.2–0.43℃ per decade;and in the growing season by 0.2–0.7℃ per decade.The air temperature in the steppe zone is rising more intensively than in the forest-steppe zone,and precipitation in the forest-steppe zone has changed more than in the steppe zone.An increase in the average annual air temperature during the growing season(May–August),combined with a shortage of atmospheric moisture or a constant amount of it,led to an increase in the degree of aridization of the territory,an increase in the frequency of droughts in the steppe zone of Northern Kazakhstan.展开更多
The concentrations of V,Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Mo,Cd,and Pb were determined in Doulonggang River,Xinyanggang River,Huangshagang River,Sheyanghe River,Guangaizongqu River,and Linhonghe River at the North of Jiangsu Pr...The concentrations of V,Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Mo,Cd,and Pb were determined in Doulonggang River,Xinyanggang River,Huangshagang River,Sheyanghe River,Guangaizongqu River,and Linhonghe River at the North of Jiangsu Province in 2019.The annual average concentrations of V,Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Mo,Cd and Pb in the six rivers were 2.20,1.22,4.53,21.9,0.13,2.79,1.77,4.00,2.97,3.87,0.01,0.19μg L^(-1)respectively.The highest concentration of most trace metals were found in Guangaizongqu River and Linhonghe River,and the lowest concentration were found in Xinyanggang River and Huangshagang River.The principal component analysis(PCA)resulted of two factors together explained 91.2%of the variance with>1initial eigenvalue,indicating that both natural and anthropogenic activities were contributing factors as the source of metal abundance in rivers of northern Jiangsu Province.The first major component represented the influence of anthropogenic activities,including industry and agriculture,with a contribution rate of 54.1%,affected Cr,Fe,Cu,Zn,Mo,Cd and Pb.The second(such as V,Mn,Co,Ni,As)was a mixed source,including the natural processes such as precipitation,erosion and weathering and anthropogenic action like industry and agriculture,with a contribution rate of 37.1%.Seasonal variations in trace metal concentrations were influenced by temperature,salinity,water discharge,and input of external pollutants.The highest concentrations were found in wet season and were strongly influenced by rainfall and seasonal industrial and agricultural activities.展开更多
Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological el...Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological element trends were analyzed using theβ-z-h three-parameter indication method.The Mann-Kendall,Pettitt,moving T,and Yamamoto methods were used to test the mutation point of hydrological elements.The Budyko framework was used to quantitatively assess the impacts of climate change and multiple human activities on runoff reduction.The results showed that(1):Precipitation(PRE),potential evapotranspiration(E0),and temperature(TEM)showed increasing trends;runoff in the Huangfuchuan,Gushanchuan,Kuye River,Tuwei River,Wuding River,Qingjian River,and Yanhe River catchments showed decreasing trends(HFC,GSC,KYR,TWR,WDR,QJR,YR);whereas runoff in the Jialu River(JLR)catchment showed a“V-shaped”trend from 1980 to2020.(2)Runoff was positively correlated with PRE and negatively correlated with E0and the subsurface index(n),with the elasticity coefficients of PRE,E0,and n showing an increasing trend in the change period.(3)Human activities were a key factor in runoff reduction,although the impact of different human activities showed spatial variations.This study provides a scientific foundation for achieving the sustainable development of water resources in mining areas.展开更多
Owen McCafferty’s Quietly(2012),a two-hander set in an Irish pub,explores how the Troubles continue to shape everyday life in Northern Ireland-an aspect often overlooked in official narratives that celebrate the succ...Owen McCafferty’s Quietly(2012),a two-hander set in an Irish pub,explores how the Troubles continue to shape everyday life in Northern Ireland-an aspect often overlooked in official narratives that celebrate the success of the peace process.The presence of an immigrant character and modern communication devices in the traditional Irish pub setting signifies a new phase of Northern Irish society following the signing of the Good Friday Agreement.However,the tense and fragmented conversation between the protagonists,along with their sense of disorientation,reveals the persistence of sectarian divisions and the paralysis of everyday life,which,in turn,reinforce narrow conceptions of identity and lead to the ongoing cycle of violence.By bringing the two protagonists together to confront their past and jointly recount the most devastating day of their lives under the witness of a third party,McCafferty presents the possibility of transcending decades of division at the everyday level,suggesting that true peace requires not only political agreements but also open dialogue between opposing sides and a renewal of values through the enrichment of individual lived experiences.展开更多
This study explores the determinants of impact on ecology in Northern Tanzania.By examining key socio-economic,institutional,and structural factors influencing engagement the study provides insights in strengthening a...This study explores the determinants of impact on ecology in Northern Tanzania.By examining key socio-economic,institutional,and structural factors influencing engagement the study provides insights in strengthening agribusiness networks and improving livelihoods.Data was collected from 215 farmers and 320 traders through a multistage sampling procedure.Heckman AI sample selection model was used in data analysis whereby the findings showed key factors influencing farmers’decisions on ecology were gender and years of formal education at p<0.1,and access to finance and off-farm income at p<0.05.The degree of farmers participation in social groups was influenced by age,household size,off-farm income and business network at p<0.05,number of years in formal education and access to finance at p<0.01,and distance to the market at p<0.1.The decision of traders to impact on ecology was significantly influenced by age and trading experience at p<0.1.Meanwhile,the degree of their involvement in social groups was strongly affected by gender,formal education,and trust at p<0.01,as well as by access to finance and business networks at p<0.05.The study concluded that natural ecology is influenced by socio economic and structural factors but trust among group members determine the degree of participation.The study recommends that strategies to improve agribusiness networks should understand underlying causes of impact on ecology and strengthen available social groups to improve performance of farmers and traders.展开更多
Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemi...Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemic hotspot for DENV transmission in Vietnam[2,3].The largest outbreak occurred in 2017,with more than 36000 cases and 7 deaths reported,causing by all four serotypes with the predominance of DENV1,following by DENV2[4,5].During the following dengue season,we collected 390 blood and serum samples from 197 hospitalized patients in a national hospital in Hanoi city,Northern Vietnam to identify the circulating DENV serotypes responsible for the 2018-2019 outbreak.展开更多
The Erenhot-Huailai zone, as an important dust emission source area in northern China, affects the air quality of Beijing City, Tianjin City, and Hebei Province and human activities in this zone have a profound impact...The Erenhot-Huailai zone, as an important dust emission source area in northern China, affects the air quality of Beijing City, Tianjin City, and Hebei Province and human activities in this zone have a profound impact on surface dust emission. In order to explore the main source areas of surface dust emission and quantify the impacts of human activities on surface dust emission, we investigated the surface dust emission of different land types on the Erenhot-Huailai zone by model simulation, field observation, and comparative analysis. The results showed that the average annual inhalable atmospheric particles(PM_(10)) dust emission fluxes in arid grassland, Hunshandake Sandy Land, semi-arid grassland,semi-arid agro-pastoral area, dry sub-humid agro-pastoral area, and semi-humid agro-pastoral area were 4.41, 0.71, 3.64, 1.94, 0.24, and 0.14 t/hm^(2), respectively, and dust emission in these lands occurred mainly from April to May. Due to the influence of human activities on surface dust emission, dust emission fluxes from different land types were 1.66–4.41 times greater than those of their background areas, and dust emission fluxes from the main dust source areas were 1.66–3.89 times greater than those of their background areas. According to calculation, the amount of PM_(10) dust emission influenced by human disturbance accounted for up to 58.00% of the total dust emission in the study area. In addition, the comparative analysis of model simulation and field observation results showed that the simulated and observed dust emission fluxes were relatively close to each other, with differences ranging from 0.01 to 0.21 t/hm^(2) in different months, which indicated that the community land model version 4.5(CLM4.5) had a high accuracy. In conclusion, model simulation results have important reference significance for identifying dust source areas and quantifying the contribution of human activities to surface dust emission.展开更多
The snow density is a fundamental variable of the snow physical evolution processes,which can reflect the snowpack condition due to the thermal and gravitational compaction.Snow density is a bridge to transfer snow de...The snow density is a fundamental variable of the snow physical evolution processes,which can reflect the snowpack condition due to the thermal and gravitational compaction.Snow density is a bridge to transfer snow depth to snow water equivalent(SWE)for the snow water resources research.Therefore,it is important to understand the spatiotemporal distribution of snow density for the appropriate estimation of SWE.In this study,in situ snow densities from more than 6,000 stations in the Northern Hemisphere were used to analyze the spatial and temporal variations in snow density.The results displayed that snow density varied spatially and temporally in the Northern Hemisphere,with range of below 0.1 to over 0.4 g/cm^(3).The average snow densities in the mountainous regions of western North America,southeastern Canada,and Europe range from approximately 0.24 to 0.26 g/cm^(3),which is significantly greater than the values of 0.16–0.17 g/cm^(3)observed in Siberia,central Canada,the Great Plains of the United States,and China.The seasonal growth rates also present large spatial heterogeneity.The rates are over 0.024 g/cm^(3)per month in Southeastern Canada,the west mountain of North America and Europe,approximately 0.017 g/cm^(3)per month in Siberia,much larger than approximately 0.004 g/cm^(3)per month in other regions.Snow cover duration is a critical factor to determine the snow density.This study endorses the small snow density in China based on meteorological station observations,which results from that the meteorological stations are dominantly distributed in plain areas with relative short snow cover duration and shallow snow.展开更多
The aim of this study is to analyze the risk factors and clinical characteristics of pulmonary embolism in northern Shaanxi.In this study,162 patients with venous thrombosis admitted between June 2023 and June 2024 un...The aim of this study is to analyze the risk factors and clinical characteristics of pulmonary embolism in northern Shaanxi.In this study,162 patients with venous thrombosis admitted between June 2023 and June 2024 underwent CT pulmonary angiography to investigate the risk factors and clinical characteristics of pulmonary embolism(PE)in northern Shaanxi.The patients were divided into a control group(no PE,n=98)and a study group(PE,n=64)based on the presence or absence of PE.Data were collected using a Case Report Form,and statistical analyses were conducted to summarize clinical features and risk factors,followed by three months of targeted therapy.Significant differences were observed between the two groups in clinical manifestations such as pleural pain,dyspnea,and hemoptysis,as well as in past medical histories(including malignant tumor history and right ventricular dysfunction),physical signs like lung rales,and laboratory parameters such as hemoglobin,albumin,white blood cell count,D-dimer,blood oxygen saturation,total cholesterol,triglycerides,and high-density lipoprotein cholesterol(all P<0.05).Multivariate logistic regression analysis identified pleural pain,dyspnea,malignancy,right ventricular dysfunction,lung rales,D-dimer,white blood cell levels,and blood oxygen saturation as risk factors for PE in patients with venous thrombosis.Following targeted therapy,the proportions of patients with pleural pain,dyspnea,and lung rales decreased significantly,with concurrent reductions in right ventricular end-diastolic inner diameter(RVD),D-dimer,and white blood cell levels,and a significant increase in blood oxygen saturation.These findings suggest that early prevention and intervention based on these risk factors can effectively reduce the incidence of PE in northern Shaanxi.展开更多
The Shangla Complex ophiolite represents a relic of the Neo-Tethyan oceanic lithosphere along the Indus Suture Zone(also known as the Main Mantle Thrust)in northern Pakistan.This section,thrust onto the continental ma...The Shangla Complex ophiolite represents a relic of the Neo-Tethyan oceanic lithosphere along the Indus Suture Zone(also known as the Main Mantle Thrust)in northern Pakistan.This section,thrust onto the continental margin between the Indian and Karakoram(Asian)plates,is predominantly composed of depleted harzburgites,dunites and chromitites.In this study,we conducted a thorough analysis of mineralogy,whole-rock geochemistry(major oxides,trace elements,PGE),and integrated Re-Os isotopic data from mantle-derived peridotites to understand their petrogenesis and melt evolution.These peridotites exhibit a depleted nature,characterized by a low modal composition of clinopyroxene,a wide forsterite content range in olivine(86.5 to 95.2),and a large variation in Cr#values(25.1–91.4).Their diverse whole-rock geochemistry further suggests varying degrees of partial melting.The Cpx-harzburgites show high average Al_(2)O_(3)(1.83 wt.%),CaO(2.27 wt.%),ΣREE(12.9 ppb),and^(187)Os/^(188)Os values between 0.13095 and 0.12571.On the other hand,the depleted harzburgites and dunites exhibit lower average Al_(2)O_(3)(0.57 wt.%and 0.14 wt.%,respectively),CaO concentration(0.59 wt.%and 0.21 wt.%,respectively),and∑REE concentrations,measured at 12.7 ppb and 8.9 ppb,respectively.The^(187)Os/^(188)Os ratios in the depleted harzburgites and dunites range from 0.12643 to 0.11777,indicating they are less radiogenic compared to the Cpx-harzburgites.The spoon-shaped rare earth elements(REE)patterns suggest that the Cpx-harzburgites underwent low degrees of partial melting(∼10%–15%),whereas the depleted harzburgites and dunites indicate somewhat higher degrees of partial melting(additional melting of the Cpx-harzburgites).The PGE abundances in these depleted harzburgites and dunites are linked to the partial melting of Cpx-harzburgites,resulting in a boninitic-like melt.Their low degree of melting and melt extraction suggests that Cpx-harzburgites initially formed at a mid-ocean ridge(MOR)spreading center or a distal fore-arc basin.In contrast,the depleted harzburgites and dunites were formed during a second phase of melting,followed by refertilization,closely associated with a supra-subduction zone(SSZ)setting.The Re-Os isotopic systematics of the Shangla Complex peridotites reveal model age clusters of ca.250 Ma and ca.450 Ma,potentially corresponding to significant tectonic events in the geodynamic evolution of the Neo-Tethyan,Rheic,and Proto-Tethyan oceans.展开更多
Fish scaleδ^(15)N(δ^(15)N_(sca))records trophic information of the whole life history for marine fishes.Data from gut content and values calculated from white muscle tissue(WMT)are insufficient for assessing trophic...Fish scaleδ^(15)N(δ^(15)N_(sca))records trophic information of the whole life history for marine fishes.Data from gut content and values calculated from white muscle tissue(WMT)are insufficient for assessing trophic level(TL)of marine fishes as they only provide the information of several months or even several days.Stable isotope analysis(SIA)of nitrogen was carried out in fish scales and WMT of 16 species from a total of 28 individuals captured from the Yellow Sea and northern East China Sea in October and November of 2019,aiming at discovering the correlation betweenδ^(15)N_(sca) and fish WMTδ^(15)N(δ^(15)NWMT),so as to useδ^(15)N_(sca) for the characterization of TLs of marine fish.Scales were analyzed without prior carbonate dissolution as a pre-processing step.TL calculated fromδ^(15)N_(sca) was compared to traditional TL formula calculated withδ^(15)N_(WMT) to estimate the accuracy.We found that there was a highly significant and positive correlation(r=0.830,P<0.001)betweenδ^(15)N_(sca) andδ^(15)N_(WMT).TL calculation results using fish scale(TL_(sca))and WMT(TL_(WMT))showed congruence(r=0.773,P<0.001),and the regression coefficient betweenδ^(15)N_(sca) andδ^(15)NWMT was used for calculating TLsca.The conversion was conducted for the purpose of comparison with previousδ^(15)N_(WMT)-based calculation results of TL.TLsca calculation results were 81.25%within the TL range of±10%calculated withδ^(15)NWMT.The findings in the present study showed thatδ^(15)N_(sca) is a viable technique for the characterization of the TL of marine fish and can help to predict food web and support the study of marine ecosystem.展开更多
Passive-roof duplexes accommodate shortening at the mountain front of many fold-and-thrust belts worldwide.These structures typically manifest at the surface by hinterland-verging backthrusts that decouple thin-skinne...Passive-roof duplexes accommodate shortening at the mountain front of many fold-and-thrust belts worldwide.These structures typically manifest at the surface by hinterland-verging backthrusts that decouple thin-skinned thrust sheets from underlying foreland-verging duplexes.Although the main fac-tors controlling the development of passive-roof duplexes have mostly been identified,some of their intrinsic characteristics are still poorly defined.These relate to their spatio-temporal relationships to thrust faults located further inland in orogens,and their ability to transport younger rocks over older ones.This study explores these issues in the Casentino-Romagna axial sector of the Northern Apennines,which expose regional forethrusts and backthrusts.Detailed field mapping and analysis of superposed tectonic structures were integrated with apatite fission-track dating for constraining the tim-ing of rock exhumation and correlated tectonic events.Collectively,the results have allowed us to inter-pret the evolution of the study area in terms of two main deformation stages.Specifically,a first,long phase(D_(1))progressed from NE-directed,in-sequence thrusting(∼18 to∼10-9 Ma)to late out-of-sequence thrusting(∼8-5 Ma).A successive deformation phase,that we refer to as D_(2)(∼4-2 Ma),con-sisted of backthrusts and associated folds that were ubiquitous and systematically overprinted onto the foreland-verging D_(1)structures.Such retrovergent structures identify a late deformation phase dom-inated by the development of passive-roof duplexes that propagated hinterlandward into the orogen up to beyond the primary watershed ridge.Orogen-scale processes controlled the evolution of forelandward D_(1)-phase thrusts,although late erosion could have played a major role by bringing the Apennine thrust wedge toward an undercritical state.The latter conditions could have contributed to keeping the out-of-sequence thrusts active,and eventually promoted the development of the D_(2)passive-roof duplexes.展开更多
Due to global warming and diminishing ice cover in Arctic regions,the northern sea route(NSR)has attracted increasing attention in recent years.Extreme cold temperatures and high wind speeds in Arctic regions present ...Due to global warming and diminishing ice cover in Arctic regions,the northern sea route(NSR)has attracted increasing attention in recent years.Extreme cold temperatures and high wind speeds in Arctic regions present substantial risks to vessels operating along the NSR.Consequently,analyzing extreme temperature and wind speed values along the NSR is essential for ensuring maritime operational safety in the region.This study analyzes wind and temperature data spanning 40 years,from 1981 to 2020,at four representative sites along the NSR for extreme value analysis.The average conditional exceedance rate(ACER)method and the Gumbel method are employed to estimate extreme wind speed and air temperature at these sites.Comparative analysis reveals that the ACER method provides higher accuracy and lower uncertainty in estimations.The predicted extreme wind speed for a 100-year return period is 30.36 m/s,with a minimum temperature of-56.66°C,varying across the four sites.Furthermore,the study presents extreme values corresponding to each return period,providing temperature extremes as a basis for guiding steel thickness specifications.These findings provide valuable reference for designing polar vessels and offshore structures,contributing to enhanced engineering standards for Arctic conditions.展开更多
The Late Paleozoic-Early Mesozoic sedimentary system of the Luang Prabang Paleotethyan back-arc basin in northern Laos is important for investigating sedimentary provenance,paleogeographic patterns,and the tectonic ev...The Late Paleozoic-Early Mesozoic sedimentary system of the Luang Prabang Paleotethyan back-arc basin in northern Laos is important for investigating sedimentary provenance,paleogeographic patterns,and the tectonic evolution of the eastern Paleotethyan Ocean.This study presents systematic stratigraphy,petrology,geochemistry,and detrital zircon U-Pb-Hf isotopic analyses for the Late Carboniferous-Jurassic sedimentary strata on both sides of the Luang Prabang Basin.Based on distinct stratigraphic ages and provenance characteristics,the clastic rock samples can be divided into four groups.The Group 1 Late Carboniferous-Early Permian samples from the western part of the basin yield detrital zircon age-peaks of~348 and~1425 Ma,with correspondingεHf(t)values ranging from-2.0 to+15.5 and+1.5 to+14,respectively.The age spectrum of Group 2 Late Carboniferous-Early Permian samples from the eastern part of the basin shows major age-peaks of~287 and~1860 Ma,withεHf(t)values of-5.9--0.9 and-3.6-+4.2,respectively.Group 3 Late Permian-Triassic samples exhibit age-peaks of~242 and~1853 Ma,along withεHf(t)values of-0.7-+14.4 and-5.4--1.8,respectively.Group 4 Middle-Late Jurassic samples yield agepeaks of~237,~431,~813,~1833,and~2460 Ma,lacking Late Devonian(413-345 Ma)detrital zircons.All these data collectively suggest that the Group 1 sample primarily originated from the Sukhothai arc in western Indochina,Group 2 was from the Kontum and Truong Son in eastern Indochina,and Group 3 has a combined provenance of the Sukhothai,Kontum,and Truong Son.Regional comparisons suggest that the Jurassic provenance was mainly derived from South China,which was imported through the northern river system.Our data,combined with the regional angular unconformities between the Jurassic continental strata and pre-Jurassic marine strata,suggest that the Luang Prabang Basin transformed into a superimposed collisional retroforeland basin during the Jurassic,and the closure of the Luang Prabang BAB occurred before the Late Triassic.展开更多
The early-maturing cotton planting area in northern Xinjiang is a significant high-quality cotton production region in China.The screening and identification of early-maturing cotton germplasm resources are essential ...The early-maturing cotton planting area in northern Xinjiang is a significant high-quality cotton production region in China.The screening and identification of early-maturing cotton germplasm resources are essential for the selection and breeding of early-maturing machine-picked cotton varieties,thereby facilitating the development of high-quality early-maturing machine-picked cotton materials.In this study,19 self-fertilized early-maturing materials were screened and identified.Among these,the varieties G15 and G9 were selected based on their superior overall traits.Notably,the G9 variety exhibited exceptional early-maturing characteristics,with a reproductive period of 116 d.展开更多
Regular quantitative assessments of regional ecological environment quality(EEQ)and driving force analyses are highly important for environmental protection and sustainable development.Northern China is a typical clim...Regular quantitative assessments of regional ecological environment quality(EEQ)and driving force analyses are highly important for environmental protection and sustainable development.Northern China is a typical climate-sensitive and ecologically vulnerable area,however,the changes in EEQ in this region and their underlying causes remain unclear.Traditional evaluations of EEQ rely primarily on the remote sensing ecological index(RSEI),which lacks assessments of indicators such as greenness(NDVI),humidity(WET),heat(LST),and dryness(NDBSI).To address these issues,this study employs the principal component analysis method and the Google Earth Engine to construct an RSEI suitable for long-term and large-scale applications and analyzes the spatio-temporal variations in the RSEI,NDVI,WET,NDBSI,and LST.Additionally,geographical detectors are utilized to analyze the driving factors affecting EEQ.The results indicate the following.(1)The RSEI shows a fluctuating upward trend,with an average value of 0.4566,indicating a gradual improvement in EEQ.The EEQ exhibited significant spatial heterogeneity,with a pattern of lower values in the west and higher values in the east.(2)The NDVI and WET exhibit fluctuating increasing trends,indicating improvements in both indices.The NDBSI shows a fluctuating decreasing trend,whereas the LST presents a fluctuating increasing trend,suggesting an improvement in the NDBSI and a slight deterioration in the LST.NDVI and WET demonstrate a spatial pattern characterized by low values in the west and high values in the east.NDBSI and LST demonstrate a spatial pattern characterized by low values in the east and high values in the west.(3)Land use types and precipitation are the primary driving factors influencing the spatial differentiation of the EEQ.The explanatory power of these driving factors significantly increases under their interactions,particularly the interaction between land use types and other driving factors.This study fills the gap in existing EEQ evaluations that analyze only the RSEI without considering the NDVI,WET,NDBSI,and LST.The findings provide new insights for EEQ assessments and serve as a scientific reference for environmental protection and sustainable development.展开更多
Previous studies have often focused on monitoring grassland growth as the primary target of remote sensing investigations on grassland ecological restoration in the northern Tibetan Plateau,overlooking the crucial rol...Previous studies have often focused on monitoring grassland growth as the primary target of remote sensing investigations on grassland ecological restoration in the northern Tibetan Plateau,overlooking the crucial role played by gravel in the ecological restoration of these grasslands.This study utilizes supervised classification and segmentation techniques based on machine learning to extract gravel morphology profiles from field-sampled plot images and calculate their characteristic parameters.Employing a multivariate linear approach combined with Principal Component Analysis(PCA),a model for inferring gravel characteristic parameters is constructed.Statistical features,particle size characteristics,and spatial distribution patterns of gravel are analyzed.Results reveal that gravel predominantly exhibit sub-rounded shapes,with 80%classified as fine gravel.The coefficients of determination(R2)between gravel particle size and coverage,perimeter,and area are 0.444,0.724,and 0.557,respectively,indicating linear relationships.The cumulative contribution rate of the top five remote sensing factors is 95.44%,with the first geological factor contributing 77.64%,collectively reflecting the primary information of the 20 factors used.Modeling shows that areas with larger gravel particle sizes correspond to increased perimeter and coverage.Gravels in the Nagqu Prefecture of northern Xizang have a particle size range of 4-8 mm,primarily comprising fine gravel which accounts for 94.61%.These findings provide a scientific basis for extracting gravel characteristic parameters and understanding their spatial distribution variations in the northern Tibetan Plateau.展开更多
The Zongwulong Shan-Qinghai Nanshan tectonic belt of the northern Xizang Plateau experienced a protracted tectonica history,including the openings and closures of the Proto-and Paleo-Tethyan Oceans.Although the tecton...The Zongwulong Shan-Qinghai Nanshan tectonic belt of the northern Xizang Plateau experienced a protracted tectonica history,including the openings and closures of the Proto-and Paleo-Tethyan Oceans.Although the tectonic belt has been extensively studied,details regarding the tectonic processes involved in its development remain controversial.To better constrain the tectonic processes of this tectonic belt,we conducted detailed field geological mapping,zircon U-Pb geochronology,and whole-rock geochemical and Sr-Nd isotopic analyses.Our results show that intrusive rocks in the tectonic belt crystallized in ca.292-233 Ma,perhaps in an arc/subduction setting.Geochemical and Sr-Nd isotopic data suggest that Early Permian-Late Triassic ultramaficintermediate intrusions were sourced from the enriched mantle,whereas intermediate-acidic rocks were sourced from mixed crust-mantle.We present the tectonic model that involves:(1)Early Devonian-Early Permian intracontinental extension occurred in the northern margin of the Qaidam continent(ca.416-292 Ma);(2)Early Permian-Late Triassic northward subduction of the Paleo-Tethyan Ocean resulted in arc magmatism(ca.292-233 Ma);and(3)subsequent Late Triassic intracontinental extension(ca.233-215 Ma).Our results suggest that the Late Paleozoic-Early Mesozoic development of the Zongwulong Shan-Qinghai Nanshan was related to the opening,subduction,and slab retreat of the Paleo-Tethyan Ocean,which has key implications for the tectonic evolution of the northern Tibetan Plateau.展开更多
The agro-pastoral ecotone in northern China (APENC) is an ecologically fragile region with a variable climate and unbalanced socioeconomic development.Identifying the spatial range and transitional dynamics of the APE...The agro-pastoral ecotone in northern China (APENC) is an ecologically fragile region with a variable climate and unbalanced socioeconomic development.Identifying the spatial range and transitional dynamics of the APENC is crucial for understanding the delicate balance between regional ecology,the economy,and society.The human-Earth system provides a comprehensive research framework in which human activities and the natural environment are viewed as interdependent and dynamically interactive.Guided by the principles of human-Earth system science,in this study,the boundaries of the APENC are identified by integrating core parameters,including water,land,climate,ecology,and human factors.Raster-based spatial data analysis is employed to examine the spatial and temporal evolution of the APENC from 1990 to 2020.The APENC extends from northeast to southwest along the central axis of northern China,displaying trends of contraction and fragmentation over time,with its centre of gravity shifting closer to the Hu Huanyong Line.The peripheral areas exhibit heightened sensitivity to environmental and ecological changes,highlighting the region’s vulnerability to external pressures.In this study,management strategies grounded in sustainable development principles are proposed,a framework for integrating ecological changes with socioeconomic strategies is established,and actionable guidance for policymakers to promote sustainable development in this fragile and dynamic region is provided.展开更多
基金Supported by Guangdong Province Philosophy and Social Science Planning Project(GD24CGL18&GD23CGL02).
文摘Investigation and analysis of the current status of farmers'livelihood capital and promptly discovering and solving problems in farmers'livelihood development are of great practical significance for optimizing farmers'livelihood strategies and enhancing farmers'livelihood sustainable development capability.Based on the framework of sustainable livelihood analysis,taking Yangshan County as an example,this paper uses field surveys,questionnaires and interviews to summarize and analyze the current status and characteristics and main problems of local farmers'livelihood capitals on the basis of the data of 628 farmer samples.It proposes countermeasures for future development of farmers'livelihoods.Implementing these strategies will be helpful for improving the livelihoods capital structure of farmers'and enhancing their sustainable development capability.
文摘The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The most important result of the work is the revealed inverse relationship between grain yields and the temperature of the growing season:low-yielding years are associated with high temperatures and droughts,and high-yielding years are associated with lower temperatures and an optimal ratio of heat and moisture.The novelty of this study is the use of the method of hydrological and climatic calculations in identifying the nature of temperature variability and precipitation in the territory of Northern Kazakhstan for the modern period(1991–2020)compared with the base period(1961–1990).At all the studied meteorological stations,there is a tendency for the average annual temperature and the temperature of the growing season to increase:in the forest-steppe zone with an average warming intensity of 0.3–0.33℃ per decade;in the steppe zone by 0.2–0.43℃ per decade;and in the growing season by 0.2–0.7℃ per decade.The air temperature in the steppe zone is rising more intensively than in the forest-steppe zone,and precipitation in the forest-steppe zone has changed more than in the steppe zone.An increase in the average annual air temperature during the growing season(May–August),combined with a shortage of atmospheric moisture or a constant amount of it,led to an increase in the degree of aridization of the territory,an increase in the frequency of droughts in the steppe zone of Northern Kazakhstan.
基金funded by the National Natural Science Foundation of China(Nos.42130410)the Joint Fund between NSFC and Shandong Province(No.U1906210)。
文摘The concentrations of V,Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Mo,Cd,and Pb were determined in Doulonggang River,Xinyanggang River,Huangshagang River,Sheyanghe River,Guangaizongqu River,and Linhonghe River at the North of Jiangsu Province in 2019.The annual average concentrations of V,Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Mo,Cd and Pb in the six rivers were 2.20,1.22,4.53,21.9,0.13,2.79,1.77,4.00,2.97,3.87,0.01,0.19μg L^(-1)respectively.The highest concentration of most trace metals were found in Guangaizongqu River and Linhonghe River,and the lowest concentration were found in Xinyanggang River and Huangshagang River.The principal component analysis(PCA)resulted of two factors together explained 91.2%of the variance with>1initial eigenvalue,indicating that both natural and anthropogenic activities were contributing factors as the source of metal abundance in rivers of northern Jiangsu Province.The first major component represented the influence of anthropogenic activities,including industry and agriculture,with a contribution rate of 54.1%,affected Cr,Fe,Cu,Zn,Mo,Cd and Pb.The second(such as V,Mn,Co,Ni,As)was a mixed source,including the natural processes such as precipitation,erosion and weathering and anthropogenic action like industry and agriculture,with a contribution rate of 37.1%.Seasonal variations in trace metal concentrations were influenced by temperature,salinity,water discharge,and input of external pollutants.The highest concentrations were found in wet season and were strongly influenced by rainfall and seasonal industrial and agricultural activities.
基金Department of Water Resources of Shaanxi Province of China,No.2023slkj-8National Natural Science Foundation of China,No.51779209。
文摘Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological element trends were analyzed using theβ-z-h three-parameter indication method.The Mann-Kendall,Pettitt,moving T,and Yamamoto methods were used to test the mutation point of hydrological elements.The Budyko framework was used to quantitatively assess the impacts of climate change and multiple human activities on runoff reduction.The results showed that(1):Precipitation(PRE),potential evapotranspiration(E0),and temperature(TEM)showed increasing trends;runoff in the Huangfuchuan,Gushanchuan,Kuye River,Tuwei River,Wuding River,Qingjian River,and Yanhe River catchments showed decreasing trends(HFC,GSC,KYR,TWR,WDR,QJR,YR);whereas runoff in the Jialu River(JLR)catchment showed a“V-shaped”trend from 1980 to2020.(2)Runoff was positively correlated with PRE and negatively correlated with E0and the subsurface index(n),with the elasticity coefficients of PRE,E0,and n showing an increasing trend in the change period.(3)Human activities were a key factor in runoff reduction,although the impact of different human activities showed spatial variations.This study provides a scientific foundation for achieving the sustainable development of water resources in mining areas.
文摘Owen McCafferty’s Quietly(2012),a two-hander set in an Irish pub,explores how the Troubles continue to shape everyday life in Northern Ireland-an aspect often overlooked in official narratives that celebrate the success of the peace process.The presence of an immigrant character and modern communication devices in the traditional Irish pub setting signifies a new phase of Northern Irish society following the signing of the Good Friday Agreement.However,the tense and fragmented conversation between the protagonists,along with their sense of disorientation,reveals the persistence of sectarian divisions and the paralysis of everyday life,which,in turn,reinforce narrow conceptions of identity and lead to the ongoing cycle of violence.By bringing the two protagonists together to confront their past and jointly recount the most devastating day of their lives under the witness of a third party,McCafferty presents the possibility of transcending decades of division at the everyday level,suggesting that true peace requires not only political agreements but also open dialogue between opposing sides and a renewal of values through the enrichment of individual lived experiences.
基金financed as part of the project“Development of a methodology for instrumental base formation for analysis and modeling of the spatial socio-economic development of systems based on internal reserves in the context of digitalization”(FSEG-2023-0008).
文摘This study explores the determinants of impact on ecology in Northern Tanzania.By examining key socio-economic,institutional,and structural factors influencing engagement the study provides insights in strengthening agribusiness networks and improving livelihoods.Data was collected from 215 farmers and 320 traders through a multistage sampling procedure.Heckman AI sample selection model was used in data analysis whereby the findings showed key factors influencing farmers’decisions on ecology were gender and years of formal education at p<0.1,and access to finance and off-farm income at p<0.05.The degree of farmers participation in social groups was influenced by age,household size,off-farm income and business network at p<0.05,number of years in formal education and access to finance at p<0.01,and distance to the market at p<0.1.The decision of traders to impact on ecology was significantly influenced by age and trading experience at p<0.1.Meanwhile,the degree of their involvement in social groups was strongly affected by gender,formal education,and trust at p<0.01,as well as by access to finance and business networks at p<0.05.The study concluded that natural ecology is influenced by socio economic and structural factors but trust among group members determine the degree of participation.The study recommends that strategies to improve agribusiness networks should understand underlying causes of impact on ecology and strengthen available social groups to improve performance of farmers and traders.
基金the“Metropolitan Mosquitoes Project”funded by the Swedish Research Council for Environment,Agricultural Sciences and Spatial Planning(Formas,grant number 2016-00364).
文摘Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemic hotspot for DENV transmission in Vietnam[2,3].The largest outbreak occurred in 2017,with more than 36000 cases and 7 deaths reported,causing by all four serotypes with the predominance of DENV1,following by DENV2[4,5].During the following dengue season,we collected 390 blood and serum samples from 197 hospitalized patients in a national hospital in Hanoi city,Northern Vietnam to identify the circulating DENV serotypes responsible for the 2018-2019 outbreak.
基金supported by the National Basic Research Program of China (2016YFA0601901)Basic Scientific Research of Henan Academy of Sciences (240601083)Joint Fund of Henan Province Science and Technology Research and Development Program (225200810047)。
文摘The Erenhot-Huailai zone, as an important dust emission source area in northern China, affects the air quality of Beijing City, Tianjin City, and Hebei Province and human activities in this zone have a profound impact on surface dust emission. In order to explore the main source areas of surface dust emission and quantify the impacts of human activities on surface dust emission, we investigated the surface dust emission of different land types on the Erenhot-Huailai zone by model simulation, field observation, and comparative analysis. The results showed that the average annual inhalable atmospheric particles(PM_(10)) dust emission fluxes in arid grassland, Hunshandake Sandy Land, semi-arid grassland,semi-arid agro-pastoral area, dry sub-humid agro-pastoral area, and semi-humid agro-pastoral area were 4.41, 0.71, 3.64, 1.94, 0.24, and 0.14 t/hm^(2), respectively, and dust emission in these lands occurred mainly from April to May. Due to the influence of human activities on surface dust emission, dust emission fluxes from different land types were 1.66–4.41 times greater than those of their background areas, and dust emission fluxes from the main dust source areas were 1.66–3.89 times greater than those of their background areas. According to calculation, the amount of PM_(10) dust emission influenced by human disturbance accounted for up to 58.00% of the total dust emission in the study area. In addition, the comparative analysis of model simulation and field observation results showed that the simulated and observed dust emission fluxes were relatively close to each other, with differences ranging from 0.01 to 0.21 t/hm^(2) in different months, which indicated that the community land model version 4.5(CLM4.5) had a high accuracy. In conclusion, model simulation results have important reference significance for identifying dust source areas and quantifying the contribution of human activities to surface dust emission.
基金funded by the National Natural Science Foundation of China(Grant Nos:42125604&42171143)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0201)。
文摘The snow density is a fundamental variable of the snow physical evolution processes,which can reflect the snowpack condition due to the thermal and gravitational compaction.Snow density is a bridge to transfer snow depth to snow water equivalent(SWE)for the snow water resources research.Therefore,it is important to understand the spatiotemporal distribution of snow density for the appropriate estimation of SWE.In this study,in situ snow densities from more than 6,000 stations in the Northern Hemisphere were used to analyze the spatial and temporal variations in snow density.The results displayed that snow density varied spatially and temporally in the Northern Hemisphere,with range of below 0.1 to over 0.4 g/cm^(3).The average snow densities in the mountainous regions of western North America,southeastern Canada,and Europe range from approximately 0.24 to 0.26 g/cm^(3),which is significantly greater than the values of 0.16–0.17 g/cm^(3)observed in Siberia,central Canada,the Great Plains of the United States,and China.The seasonal growth rates also present large spatial heterogeneity.The rates are over 0.024 g/cm^(3)per month in Southeastern Canada,the west mountain of North America and Europe,approximately 0.017 g/cm^(3)per month in Siberia,much larger than approximately 0.004 g/cm^(3)per month in other regions.Snow cover duration is a critical factor to determine the snow density.This study endorses the small snow density in China based on meteorological station observations,which results from that the meteorological stations are dominantly distributed in plain areas with relative short snow cover duration and shallow snow.
文摘The aim of this study is to analyze the risk factors and clinical characteristics of pulmonary embolism in northern Shaanxi.In this study,162 patients with venous thrombosis admitted between June 2023 and June 2024 underwent CT pulmonary angiography to investigate the risk factors and clinical characteristics of pulmonary embolism(PE)in northern Shaanxi.The patients were divided into a control group(no PE,n=98)and a study group(PE,n=64)based on the presence or absence of PE.Data were collected using a Case Report Form,and statistical analyses were conducted to summarize clinical features and risk factors,followed by three months of targeted therapy.Significant differences were observed between the two groups in clinical manifestations such as pleural pain,dyspnea,and hemoptysis,as well as in past medical histories(including malignant tumor history and right ventricular dysfunction),physical signs like lung rales,and laboratory parameters such as hemoglobin,albumin,white blood cell count,D-dimer,blood oxygen saturation,total cholesterol,triglycerides,and high-density lipoprotein cholesterol(all P<0.05).Multivariate logistic regression analysis identified pleural pain,dyspnea,malignancy,right ventricular dysfunction,lung rales,D-dimer,white blood cell levels,and blood oxygen saturation as risk factors for PE in patients with venous thrombosis.Following targeted therapy,the proportions of patients with pleural pain,dyspnea,and lung rales decreased significantly,with concurrent reductions in right ventricular end-diastolic inner diameter(RVD),D-dimer,and white blood cell levels,and a significant increase in blood oxygen saturation.These findings suggest that early prevention and intervention based on these risk factors can effectively reduce the incidence of PE in northern Shaanxi.
基金supported by a grant from the Science and Technology Innovation Program of Hunan Province(Grant No.2021RC4055)Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,during the Postdoctoral research of the first author(Zaheen Ullah,Assistant Professor,University of Swat,Pakistan)at the Central South University,Changsha,China.
文摘The Shangla Complex ophiolite represents a relic of the Neo-Tethyan oceanic lithosphere along the Indus Suture Zone(also known as the Main Mantle Thrust)in northern Pakistan.This section,thrust onto the continental margin between the Indian and Karakoram(Asian)plates,is predominantly composed of depleted harzburgites,dunites and chromitites.In this study,we conducted a thorough analysis of mineralogy,whole-rock geochemistry(major oxides,trace elements,PGE),and integrated Re-Os isotopic data from mantle-derived peridotites to understand their petrogenesis and melt evolution.These peridotites exhibit a depleted nature,characterized by a low modal composition of clinopyroxene,a wide forsterite content range in olivine(86.5 to 95.2),and a large variation in Cr#values(25.1–91.4).Their diverse whole-rock geochemistry further suggests varying degrees of partial melting.The Cpx-harzburgites show high average Al_(2)O_(3)(1.83 wt.%),CaO(2.27 wt.%),ΣREE(12.9 ppb),and^(187)Os/^(188)Os values between 0.13095 and 0.12571.On the other hand,the depleted harzburgites and dunites exhibit lower average Al_(2)O_(3)(0.57 wt.%and 0.14 wt.%,respectively),CaO concentration(0.59 wt.%and 0.21 wt.%,respectively),and∑REE concentrations,measured at 12.7 ppb and 8.9 ppb,respectively.The^(187)Os/^(188)Os ratios in the depleted harzburgites and dunites range from 0.12643 to 0.11777,indicating they are less radiogenic compared to the Cpx-harzburgites.The spoon-shaped rare earth elements(REE)patterns suggest that the Cpx-harzburgites underwent low degrees of partial melting(∼10%–15%),whereas the depleted harzburgites and dunites indicate somewhat higher degrees of partial melting(additional melting of the Cpx-harzburgites).The PGE abundances in these depleted harzburgites and dunites are linked to the partial melting of Cpx-harzburgites,resulting in a boninitic-like melt.Their low degree of melting and melt extraction suggests that Cpx-harzburgites initially formed at a mid-ocean ridge(MOR)spreading center or a distal fore-arc basin.In contrast,the depleted harzburgites and dunites were formed during a second phase of melting,followed by refertilization,closely associated with a supra-subduction zone(SSZ)setting.The Re-Os isotopic systematics of the Shangla Complex peridotites reveal model age clusters of ca.250 Ma and ca.450 Ma,potentially corresponding to significant tectonic events in the geodynamic evolution of the Neo-Tethyan,Rheic,and Proto-Tethyan oceans.
基金supported by the Scientific Research Foundation of Hainan Tropical Ocean University(No.RHDRC202312)the Major Science and Technology Project of Yazhou Bay Innovation Institute of Hainan Tropical Ocean University:Research on Hainan Coastal Marine Ecological Environment and Carbon Sink(No.2022CXYZD002).
文摘Fish scaleδ^(15)N(δ^(15)N_(sca))records trophic information of the whole life history for marine fishes.Data from gut content and values calculated from white muscle tissue(WMT)are insufficient for assessing trophic level(TL)of marine fishes as they only provide the information of several months or even several days.Stable isotope analysis(SIA)of nitrogen was carried out in fish scales and WMT of 16 species from a total of 28 individuals captured from the Yellow Sea and northern East China Sea in October and November of 2019,aiming at discovering the correlation betweenδ^(15)N_(sca) and fish WMTδ^(15)N(δ^(15)NWMT),so as to useδ^(15)N_(sca) for the characterization of TLs of marine fish.Scales were analyzed without prior carbonate dissolution as a pre-processing step.TL calculated fromδ^(15)N_(sca) was compared to traditional TL formula calculated withδ^(15)N_(WMT) to estimate the accuracy.We found that there was a highly significant and positive correlation(r=0.830,P<0.001)betweenδ^(15)N_(sca) andδ^(15)N_(WMT).TL calculation results using fish scale(TL_(sca))and WMT(TL_(WMT))showed congruence(r=0.773,P<0.001),and the regression coefficient betweenδ^(15)N_(sca) andδ^(15)NWMT was used for calculating TLsca.The conversion was conducted for the purpose of comparison with previousδ^(15)N_(WMT)-based calculation results of TL.TLsca calculation results were 81.25%within the TL range of±10%calculated withδ^(15)NWMT.The findings in the present study showed thatδ^(15)N_(sca) is a viable technique for the characterization of the TL of marine fish and can help to predict food web and support the study of marine ecosystem.
文摘Passive-roof duplexes accommodate shortening at the mountain front of many fold-and-thrust belts worldwide.These structures typically manifest at the surface by hinterland-verging backthrusts that decouple thin-skinned thrust sheets from underlying foreland-verging duplexes.Although the main fac-tors controlling the development of passive-roof duplexes have mostly been identified,some of their intrinsic characteristics are still poorly defined.These relate to their spatio-temporal relationships to thrust faults located further inland in orogens,and their ability to transport younger rocks over older ones.This study explores these issues in the Casentino-Romagna axial sector of the Northern Apennines,which expose regional forethrusts and backthrusts.Detailed field mapping and analysis of superposed tectonic structures were integrated with apatite fission-track dating for constraining the tim-ing of rock exhumation and correlated tectonic events.Collectively,the results have allowed us to inter-pret the evolution of the study area in terms of two main deformation stages.Specifically,a first,long phase(D_(1))progressed from NE-directed,in-sequence thrusting(∼18 to∼10-9 Ma)to late out-of-sequence thrusting(∼8-5 Ma).A successive deformation phase,that we refer to as D_(2)(∼4-2 Ma),con-sisted of backthrusts and associated folds that were ubiquitous and systematically overprinted onto the foreland-verging D_(1)structures.Such retrovergent structures identify a late deformation phase dom-inated by the development of passive-roof duplexes that propagated hinterlandward into the orogen up to beyond the primary watershed ridge.Orogen-scale processes controlled the evolution of forelandward D_(1)-phase thrusts,although late erosion could have played a major role by bringing the Apennine thrust wedge toward an undercritical state.The latter conditions could have contributed to keeping the out-of-sequence thrusts active,and eventually promoted the development of the D_(2)passive-roof duplexes.
基金supported by the National Natural Science Foundation of China(Grant No.52201379)the Fundamental Research Funds for the Central Universities(Grant No.WUT:3120622898)+2 种基金State Key Laboratory of Structural Analysis,Optimization and CAE Software for Industrial Equipment,Dalian University of Technology(Grant No.GZ 231088)Shanghai Key Laboratory of Naval Architecture Engineering(Grant No.SE202305)funded by European Research Council project under the European Union’s Horizon 2020 research and innovation program(Grant No.TRUST CoG 2019864724).
文摘Due to global warming and diminishing ice cover in Arctic regions,the northern sea route(NSR)has attracted increasing attention in recent years.Extreme cold temperatures and high wind speeds in Arctic regions present substantial risks to vessels operating along the NSR.Consequently,analyzing extreme temperature and wind speed values along the NSR is essential for ensuring maritime operational safety in the region.This study analyzes wind and temperature data spanning 40 years,from 1981 to 2020,at four representative sites along the NSR for extreme value analysis.The average conditional exceedance rate(ACER)method and the Gumbel method are employed to estimate extreme wind speed and air temperature at these sites.Comparative analysis reveals that the ACER method provides higher accuracy and lower uncertainty in estimations.The predicted extreme wind speed for a 100-year return period is 30.36 m/s,with a minimum temperature of-56.66°C,varying across the four sites.Furthermore,the study presents extreme values corresponding to each return period,providing temperature extremes as a basis for guiding steel thickness specifications.These findings provide valuable reference for designing polar vessels and offshore structures,contributing to enhanced engineering standards for Arctic conditions.
基金supported by the National Key Research and Development Program of China(No.2023YFF0803701)the National Natural Science Foundation of China(Nos.42330302 and 42472265)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2023SP239)。
文摘The Late Paleozoic-Early Mesozoic sedimentary system of the Luang Prabang Paleotethyan back-arc basin in northern Laos is important for investigating sedimentary provenance,paleogeographic patterns,and the tectonic evolution of the eastern Paleotethyan Ocean.This study presents systematic stratigraphy,petrology,geochemistry,and detrital zircon U-Pb-Hf isotopic analyses for the Late Carboniferous-Jurassic sedimentary strata on both sides of the Luang Prabang Basin.Based on distinct stratigraphic ages and provenance characteristics,the clastic rock samples can be divided into four groups.The Group 1 Late Carboniferous-Early Permian samples from the western part of the basin yield detrital zircon age-peaks of~348 and~1425 Ma,with correspondingεHf(t)values ranging from-2.0 to+15.5 and+1.5 to+14,respectively.The age spectrum of Group 2 Late Carboniferous-Early Permian samples from the eastern part of the basin shows major age-peaks of~287 and~1860 Ma,withεHf(t)values of-5.9--0.9 and-3.6-+4.2,respectively.Group 3 Late Permian-Triassic samples exhibit age-peaks of~242 and~1853 Ma,along withεHf(t)values of-0.7-+14.4 and-5.4--1.8,respectively.Group 4 Middle-Late Jurassic samples yield agepeaks of~237,~431,~813,~1833,and~2460 Ma,lacking Late Devonian(413-345 Ma)detrital zircons.All these data collectively suggest that the Group 1 sample primarily originated from the Sukhothai arc in western Indochina,Group 2 was from the Kontum and Truong Son in eastern Indochina,and Group 3 has a combined provenance of the Sukhothai,Kontum,and Truong Son.Regional comparisons suggest that the Jurassic provenance was mainly derived from South China,which was imported through the northern river system.Our data,combined with the regional angular unconformities between the Jurassic continental strata and pre-Jurassic marine strata,suggest that the Luang Prabang Basin transformed into a superimposed collisional retroforeland basin during the Jurassic,and the closure of the Luang Prabang BAB occurred before the Late Triassic.
基金Supported by Major Project of Agricultural Biological Breeding(2024AB001)Germplasm Resource Innovation of Early-maturing Machine-picked Cotton in the Northern Xinjiang(2023RC04)New Germplasm Creation and Variety Selection and Application of Early-maturing and Anti-stress Machine-picked Cotton(2021NY01).
文摘The early-maturing cotton planting area in northern Xinjiang is a significant high-quality cotton production region in China.The screening and identification of early-maturing cotton germplasm resources are essential for the selection and breeding of early-maturing machine-picked cotton varieties,thereby facilitating the development of high-quality early-maturing machine-picked cotton materials.In this study,19 self-fertilized early-maturing materials were screened and identified.Among these,the varieties G15 and G9 were selected based on their superior overall traits.Notably,the G9 variety exhibited exceptional early-maturing characteristics,with a reproductive period of 116 d.
基金National Natural Science Foundation of China,No.41971268。
文摘Regular quantitative assessments of regional ecological environment quality(EEQ)and driving force analyses are highly important for environmental protection and sustainable development.Northern China is a typical climate-sensitive and ecologically vulnerable area,however,the changes in EEQ in this region and their underlying causes remain unclear.Traditional evaluations of EEQ rely primarily on the remote sensing ecological index(RSEI),which lacks assessments of indicators such as greenness(NDVI),humidity(WET),heat(LST),and dryness(NDBSI).To address these issues,this study employs the principal component analysis method and the Google Earth Engine to construct an RSEI suitable for long-term and large-scale applications and analyzes the spatio-temporal variations in the RSEI,NDVI,WET,NDBSI,and LST.Additionally,geographical detectors are utilized to analyze the driving factors affecting EEQ.The results indicate the following.(1)The RSEI shows a fluctuating upward trend,with an average value of 0.4566,indicating a gradual improvement in EEQ.The EEQ exhibited significant spatial heterogeneity,with a pattern of lower values in the west and higher values in the east.(2)The NDVI and WET exhibit fluctuating increasing trends,indicating improvements in both indices.The NDBSI shows a fluctuating decreasing trend,whereas the LST presents a fluctuating increasing trend,suggesting an improvement in the NDBSI and a slight deterioration in the LST.NDVI and WET demonstrate a spatial pattern characterized by low values in the west and high values in the east.NDBSI and LST demonstrate a spatial pattern characterized by low values in the east and high values in the west.(3)Land use types and precipitation are the primary driving factors influencing the spatial differentiation of the EEQ.The explanatory power of these driving factors significantly increases under their interactions,particularly the interaction between land use types and other driving factors.This study fills the gap in existing EEQ evaluations that analyze only the RSEI without considering the NDVI,WET,NDBSI,and LST.The findings provide new insights for EEQ assessments and serve as a scientific reference for environmental protection and sustainable development.
基金funded by the Major R&D and Achievement Transformation Projects of Xizang(CGZH2024000416)Science and Technology Program of Xizang(XZ202402ZD0001)Major R&D and Achievement Transformation Projects of Qinghai(2022-QY-224)。
文摘Previous studies have often focused on monitoring grassland growth as the primary target of remote sensing investigations on grassland ecological restoration in the northern Tibetan Plateau,overlooking the crucial role played by gravel in the ecological restoration of these grasslands.This study utilizes supervised classification and segmentation techniques based on machine learning to extract gravel morphology profiles from field-sampled plot images and calculate their characteristic parameters.Employing a multivariate linear approach combined with Principal Component Analysis(PCA),a model for inferring gravel characteristic parameters is constructed.Statistical features,particle size characteristics,and spatial distribution patterns of gravel are analyzed.Results reveal that gravel predominantly exhibit sub-rounded shapes,with 80%classified as fine gravel.The coefficients of determination(R2)between gravel particle size and coverage,perimeter,and area are 0.444,0.724,and 0.557,respectively,indicating linear relationships.The cumulative contribution rate of the top five remote sensing factors is 95.44%,with the first geological factor contributing 77.64%,collectively reflecting the primary information of the 20 factors used.Modeling shows that areas with larger gravel particle sizes correspond to increased perimeter and coverage.Gravels in the Nagqu Prefecture of northern Xizang have a particle size range of 4-8 mm,primarily comprising fine gravel which accounts for 94.61%.These findings provide a scientific basis for extracting gravel characteristic parameters and understanding their spatial distribution variations in the northern Tibetan Plateau.
基金supported by the National Natural Science Foundation of China(No.42372256)the Basic Science Center for Tibetan Plateau Earth System(No.41988101)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0708)。
文摘The Zongwulong Shan-Qinghai Nanshan tectonic belt of the northern Xizang Plateau experienced a protracted tectonica history,including the openings and closures of the Proto-and Paleo-Tethyan Oceans.Although the tectonic belt has been extensively studied,details regarding the tectonic processes involved in its development remain controversial.To better constrain the tectonic processes of this tectonic belt,we conducted detailed field geological mapping,zircon U-Pb geochronology,and whole-rock geochemical and Sr-Nd isotopic analyses.Our results show that intrusive rocks in the tectonic belt crystallized in ca.292-233 Ma,perhaps in an arc/subduction setting.Geochemical and Sr-Nd isotopic data suggest that Early Permian-Late Triassic ultramaficintermediate intrusions were sourced from the enriched mantle,whereas intermediate-acidic rocks were sourced from mixed crust-mantle.We present the tectonic model that involves:(1)Early Devonian-Early Permian intracontinental extension occurred in the northern margin of the Qaidam continent(ca.416-292 Ma);(2)Early Permian-Late Triassic northward subduction of the Paleo-Tethyan Ocean resulted in arc magmatism(ca.292-233 Ma);and(3)subsequent Late Triassic intracontinental extension(ca.233-215 Ma).Our results suggest that the Late Paleozoic-Early Mesozoic development of the Zongwulong Shan-Qinghai Nanshan was related to the opening,subduction,and slab retreat of the Paleo-Tethyan Ocean,which has key implications for the tectonic evolution of the northern Tibetan Plateau.
基金National Natural Science Foundation of China,No.42293271,No.42401321,No.42371210Fundamental Research Funds for the Central Universities,CHD,No.300102354101。
文摘The agro-pastoral ecotone in northern China (APENC) is an ecologically fragile region with a variable climate and unbalanced socioeconomic development.Identifying the spatial range and transitional dynamics of the APENC is crucial for understanding the delicate balance between regional ecology,the economy,and society.The human-Earth system provides a comprehensive research framework in which human activities and the natural environment are viewed as interdependent and dynamically interactive.Guided by the principles of human-Earth system science,in this study,the boundaries of the APENC are identified by integrating core parameters,including water,land,climate,ecology,and human factors.Raster-based spatial data analysis is employed to examine the spatial and temporal evolution of the APENC from 1990 to 2020.The APENC extends from northeast to southwest along the central axis of northern China,displaying trends of contraction and fragmentation over time,with its centre of gravity shifting closer to the Hu Huanyong Line.The peripheral areas exhibit heightened sensitivity to environmental and ecological changes,highlighting the region’s vulnerability to external pressures.In this study,management strategies grounded in sustainable development principles are proposed,a framework for integrating ecological changes with socioeconomic strategies is established,and actionable guidance for policymakers to promote sustainable development in this fragile and dynamic region is provided.
