The depositional environment of the sands of the cover formation is discussed. This study aims to determine the paleoenvironments of deposition of the sands of the cover formation in the Batéké Plateaus by s...The depositional environment of the sands of the cover formation is discussed. This study aims to determine the paleoenvironments of deposition of the sands of the cover formation in the Batéké Plateaus by studying sedimentary dynamics based on the description of lithological facies in the field and granulometric analyses in the laboratory. In the field, six (6) lithostratigraphic logs were surveyed and 42 sand samples were taken for laboratory analysis. In the laboratory, the samples underwent granulometric, sieving and sedimentometry analyses, after washing with running water using a 63 µm sieve. These analyses made it possible to determine the granulometric classes of the samples. The sieving results allowed to determine the granulometric parameters (mean, standard deviation, mode, median, skewness, flattening or kurtosis) using the method of moments with the software “Gradistat V.8”, granulometric parameters with which the granulometric facies, the mode of transport and the deposition environment were determined using the diagrams. Morphoscopy made it possible to determine the form and aspect of the surface of the quartz grains constituting these sands. Granulometric analyses show that these silty-clay or clayey-silty sands are fine sands and rarely medium sands, moderately to well sorted and rarely well sorted. The dominant granulometric facies is hyperbolic (sigmoid), with parabolic facies being rare. The primary mode of transport of these sands is saltation, which dominates rolling. The dispersion of points in the diagrams shows that these sands originate from two depositional environments: aeolian and fluvial. Morphoscopic analysis reveals the presence of clean rounded matt grains (RM), dirty rounded matt grains (RS), shiny blunt grains (EL) and shiny rounded grains (RL). The rounded matt grains exhibit several impact marks. The presence of dirty rounded grains with a ferruginous cement on their surface indicates that these sands have been reworked. These sands have undergone two types of transport, first by wind (aeolian environment) and then by water (fluvial environment).展开更多
Variation in the location of the South Asian High （SAH） in early boreal summer is strongly influenced by elevated surface heating from the Tibetan Plateau （TP） and the Iranian Plateau （IP）. Based on observationa...Variation in the location of the South Asian High （SAH） in early boreal summer is strongly influenced by elevated surface heating from the Tibetan Plateau （TP） and the Iranian Plateau （IP）. Based on observational and ERA-Interim data, diagnostic analyses reveal that the interannual northwestward-southeastwaxd （NW-SE） shift of the SAH in June is more closely correlated with the synergistic effect of concurrent surface thermal anomalies over the TP and IP than with each single surface thermal anomaly over either plateau from the preceding May. Concurrent surface thermal anomalies over these two plateaus in May are characterized by a negative correlation between sensible heat flux over most parts of the TP （TPSH） and IP （IPSH）. This anomaly pattern can persist till June and influences the NW-SE shift of the SAH in June through the release of latent heat （LH） over northeastern India. When the IPSH is stronger （weaker） and the TPSH is weaker （stronger） than normal in May, an anomalous cyclone （anticyclone） appears over northern India at 850 hPa, which is accompanied by the ascent （descent） of air and anomalous convergence （divergence） of moisture flux in May and June. Therefore, the LH release over northeastern India is strengthened （weakened） and the vertical gradient of apparent heat source is decreased （increased） in the upper troposphere, which is responsible for the northwestward （southeastward） shift of the SAH in June.展开更多
Oceanic plateaus are large igneous provinces in the oceans,created by massive underwater eruptions,but their late-stage volcanism is poorly understood.With the addition of recent high-quality bathymetric data to exist...Oceanic plateaus are large igneous provinces in the oceans,created by massive underwater eruptions,but their late-stage volcanism is poorly understood.With the addition of recent high-quality bathymetric data to existing data,286 secondary cones were discovered over Shatsky Rise oceanic plateau.These cones with steeper flank slopes(mean 6.1°±4.4°)and smaller sizes(102–1923 m in height)are morphologically distinct from the plateau,and they are thought to have formed after the main volcanic episodes.Cone height and characteristic height(420 m)are close to seamounts in the Pacific Ocean,whereas greater than those in the Atlantic Ocean.Mean flatness of Shatsky Rise’s cones(0.25±0.20)are similar to that of seamounts in both Pacific and Atlantic Oceans,but notably density in cone distribution(0.56 km^-3)and their mean slope are significantly lower than those of seamounts in the two oceans.Lower slopes of secondary cones within Shatsky Rise may be explained by higher effusion rates of remaining magma.Although cone formation was expected to have a link to rifting by seafloor spreading,weak relationship between cone orientation and magnetic anomaly pattern implies that the expectation is negative.Moreover,weak correlation between the cone height and depth indicates it is not true that volcanic cones grow taller when they occur closer to the massif summits with thicker oceanic crust,which was suggested as the increase in hydraulic pressure.Cone height and flatness are also not strongly related,implying that remaining magma supply was too limited to foster the cones to critical height.展开更多
Taking Niyang River Basin as an example, applying with the indices of landscape pattern, the indices of ecological risk of ecosystems are calculated in this paper, which takes the value of ecological loss of main ecos...Taking Niyang River Basin as an example, applying with the indices of landscape pattern, the indices of ecological risk of ecosystems are calculated in this paper, which takes the value of ecological loss of main ecosystem as the evaluation standard and takes into account the impacts of probability or the velocity of main hazards and event of the ecosystem. And the grades of ecological risk are assessed. According to the results of assessment, the ecological risk grades of the basin are divided into five classes. From the first grade risk to the fifth grade risk, the values of regional risk indices gradually reduce. The first grade risk areas mainly distribute in Niyang river and its branches downstream and the surrounding areas of main towns. And the basin area of non-valley region and the headstream regions of the branches are the fifth grades risk areas. This evaluation results provide the basis to the regional sustainable development.展开更多
As one of the main non-zonal factors,the mass elevation effect(MEE)has significant impacts on both regional climates and mountain ecological patterns.In recent years,with the development of quantitative techniques and...As one of the main non-zonal factors,the mass elevation effect(MEE)has significant impacts on both regional climates and mountain ecological patterns.In recent years,with the development of quantitative techniques and methods,quantitative studies on the MEE and its implication on mountain altitudinal belts have developed rapidly.However,some issues have not been solved yet,such as high errors in spatial temperature estimations and difficulties in the definition and extraction of intramountain base elevation.Moreover,there is still a lack of comparative studies on the MEE and its influence on treelines and snowlines as most studies were conducted on specific mountains or plateaus.To compare the MEE magnitudes of the Tibetan Plateau(TP)and the Bolivian Plateau(BP),we estimated the correspondent air temperatures and simulated the solar radiations based on MODIS surface temperature,station observation,and treeline data.Then,we analyzed the elevation of the 10℃isotherms on the two plateaus,the temperatures at the same elevation,and the solar radiations.According to the mechanism of the MEE and the relationship of solar radiation and treeline,we constructed treeline models for the two plateaus through a stepwise regression analysis by considering several influencing factors of the MEE(e.g.,air temperature and precipitation)and using solar radiation as its proxy.The results showed that:(1)the MEE magnitude on the TP is equivalent to that on the BP although the former is slightly higher than the latter;(2)the MEE strongly influences the highest treelines in the northern and southern hemispheres,which both occur on the two plateaus.Notably,the treeline distribution models based on solar radiation had higher accuracies than those models with parameters of temperature and precipitation(the adjusted R^(2)values were 0.76 for the TP and 0.936 for the BP),indicating that solar radiation can be used to quantify the MEE and its implications on treelines.Overall,the results of this study can serve as a basis for subsequent analyses on the MEE’s impact factors.展开更多
In southern Asia,there are three large-scale wave-like mountains ranging from the Tibetan Plateau westward to the Iranian Plateau and the Armenian Plateau.On the southern side between plateaus,there are the Indian Pen...In southern Asia,there are three large-scale wave-like mountains ranging from the Tibetan Plateau westward to the Iranian Plateau and the Armenian Plateau.On the southern side between plateaus,there are the Indian Peninsula and the Arabian Peninsula.What dynamic mechanisms form the directional alignment of the three plateaus with the two peninsulas remains a mystery.In the early stages of the Earth’s geological evolution,the internal structure of the Earth was that the center was a solid core,and the outmost layer was a thin equatorial crust zone separated by two thick pristine continents in polar areas,while the middle part was a deep magma fluid layer.Within the magma fluid layer,thermal and dynamic differences triggered planetary-scale vertical magma cells and led to the core-magma angular momentum exchange.When the core loses angular momentum and the magma layer gains angular momentum,the movement of upper magma fluids to the east and the tropical convergence zone(TCZ)drives the split and drift of two thick pristine continents,eventually forming the current combination of these plateaus and peninsulas and their wave-like arrangement along the east-west direction.Among them,the horizontal orthogonal convergence(collision)of upper magma fluids from the two hemispheres excited the vertical shear stress along the magma TCZ,which is the dynamic mechanism of mountain uplifts on the north side and plate subductions on the south side.To confirm this mechanism,two examples of low-level winds are used to calculate the correspondence between cyclone/anticyclonic systems generated by the orthogonal collision of airflows along the atmospheric TCZ and satellite-observed cloud systems.Such comparison can help us revisit the geological history of continental drift and orogeny.展开更多
Cryogenic wedges developed due to very cold,rather arid conditions during the maximum of the last cold event when the drying up of the neighboring China Sea resulted in the failure of the East Asian Monsoon.As the cli...Cryogenic wedges developed due to very cold,rather arid conditions during the maximum of the last cold event when the drying up of the neighboring China Sea resulted in the failure of the East Asian Monsoon.As the climate ameliorated and the Monsoon rains reappeared,ice-wedges developed.Further warming permitted thawing of the ice infillings accompanied by replacement of the ice by sediments partly from the host ground as well as from the surface by wind or sheet wash.In cases of extreme surface water flow on slopes after 10 ka B.P.,small baydjarakhs typically c.50 cm high developed,only to have the resulting hollows infilled by sediments carried by wind and/or sheet wash.These shallow structures form a network on top of many of the cryogenic wedges.This complex history makes dating the ages of the wedges difficult using OSL methodology.Unfortunately,past field work ignored the problem of the angle of the cut face to the direction of the wedge infilling when sampling the contents of the narrow wedges,resulting in potential contamination of the samples with the host sediment.Sampling of the larger deposits should be alright,but the likelihood of contamination makes the interpretation of the resulting OSL dates from the narrow wedges questionable.Primary wedges consisting of primary mineral infillings should still have similar OSL dates with depth for a given wedge,but the distinction between ice-wedge infillings and soil wedges is difficult since both can exhibit older dates of the infillings with depth.The available data suggests that ice-wedges were significantly more common than sediment-filled primary wedges.A protocol to avoid having to obtain large numbers of OSL dates by more careful field sampling and the use of grain size determinations is provided in the Appendix.展开更多
The kagome lattice,with its unique geometric structure,has emerged as a leading platform for exploring quantum many-body physics,particularly in the study of quantum spin liquids(QSLs)and unconventional superconductiv...The kagome lattice,with its unique geometric structure,has emerged as a leading platform for exploring quantum many-body physics,particularly in the study of quantum spin liquids(QSLs)and unconventional superconductivity.This review highlights recent advancements in the investigations of QSLs,fractional magnetization plateau phases in kagome antiferromagnets,and unconventional superconductivity in vanadium-based kagome superconductors.We begin by examining the classical ground-state properties of the nearest-neighbor kagome antiferromagnetic Heisenberg model and introducing recent experimental progress in the study of QSLs and fractional magnetization plateau phases.Next,we discuss the fermionic description of the QSL states,along with related gauge theory and the variational Monte Carlo(VMC)method.We then focus on discussing the VMC studies of QSLs and magnetization plateau phases in kagome antiferromagnets.For superconductivity in kagome systems,we first analyze the characteristics of the electronic structure and the possible associated electronic instabilities.Finally,we review recent experimental advances in unconventional superconductivity in AV_(3)Sb_(5)(A=K,Rb,Cs),with a particular focus on chiral superconductivity and pairing density waves.展开更多
Osteoarthritis(OA)is a degenerative skeletal condition marked by the loss of articular cartilage and changes to subchondral bone homeostasis.Treatments for OA beyond full joint replacement are lacking primarily due to...Osteoarthritis(OA)is a degenerative skeletal condition marked by the loss of articular cartilage and changes to subchondral bone homeostasis.Treatments for OA beyond full joint replacement are lacking primarily due to gaps in molecular knowledge of the biological drivers of disease.Mass Spectrometry Imaging(MSI)enables molecular spatial mapping of the proteomic landscape of tissues.Histologic sections of human tibial plateaus from knees of human OA patients and cadaveric controls were treated with collagenase Ⅲ to target extracellular matrix(ECM)proteins prior to MS Imaging of bone and cartilage proteins.Spatial MS imaging of the knee identified distinct areas of joint damage to the subchondral bone underneath areas of lost cartilage.This damaged bone signature extended underneath remaining cartilage in OA joints,indicating subchondral bone remodeling could occur before full thickness cartilage loss in OA.Specific ECM peptide markers from OA-affected medial tibial plateaus were compared to their healthier lateral halves from the same patient,as well as to healthy,age-matched cadaveric knees.Overall,31 peptide candidates from ECM proteins,including Collagen alpha-1(Ⅰ),Collagen alpha-1(Ⅲ),and surprisingly,Collagen alpha-1(Ⅵ)and Collagen alpha-3(Ⅵ),exhibited significantly elevated abundance in diseased tissues.Additionally,highly specific hydroxyproline-containing collagen peptides,mainly from collagen typeⅠ,dominated OA subchondral bone directly under regions of lost cartilage but not areas where cartilage remained intact.A separate analysis of synovial fluid from a second cohort of OA patients found similar regulation of collagens and ECM proteins via LC-MS/MS demonstrating that markers of subchondral bone remodeling discovered by MALDI-MS may be detectable as biomarkers in biofluid samples.The identification of specific protein markers for subchondral bone remodeling in OA advances our molecular understanding of disease progression in OA and provides potential new biomarkers for OA detection and disease grading.展开更多
Variational quantum algorithms(VQAs)with random structures have poor trainability due to the exponentially vanishing gradient as the circuit depth and the qubit number increase.This result leads to a general belief th...Variational quantum algorithms(VQAs)with random structures have poor trainability due to the exponentially vanishing gradient as the circuit depth and the qubit number increase.This result leads to a general belief that a deep circuit will not be feasible.In this work,we provide a viable solution to the vanishing gradient problem for deep VQAs with theoretical guarantees.Specifically,we prove that for quantum controlled-layer and quantum residual network(QResNet),architectures,the expectation of the gradient norm can be lower bounded by a value that is independent of the qubit number and the circuit depth.Our results follow from a careful analysis of the gradient behavior on parameter space consisting of rotation angles,as employed in almost all VQAs,instead of relying on impractical 2-design assumptions.We conduct several numerical experiments as verifications,where only our circuits are trainable and converge,while hardware-efficient and random circuits with similar number of parameters in comparison cannot converge.展开更多
This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian Ocean.We first calculated the relative distance between the So...This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian Ocean.We first calculated the relative distance between the Southwest Indian Ridge(SWIR)and relevant hotspots on the basis of models of plate reconstruction,and then calculated the corresponding excess magmatic anomalies of the hotspots on the basis of residual bathymetry and Airy isostasy.The results reveal that the activities of the Marion hotspot can be divided into three main phases:interaction with the paleo-Rodrigues triple junction(73.6-68.5 Ma),interaction with the SWIR(68.5-42.7 Ma),and intra-plate volcanism(42.7-0 Ma).These three phases correspond to the formation of the eastern,central,and western parts of the Del Cano Rise,respectively.The magnitude and apparent periodicity of the magmatic volume flux of the Marion hotspot appear to be dominated by the hotspot-ridge distance.The periodicity of the Marion hotspot is about 25 Ma,which is much longer than that of the Hawaii and Iceland hotspots(about 15 Ma).展开更多
Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that c...Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that confer cold and UV resistance on the crop also facilitate human adaptation to high-altitude stresses.Specifically,β-glucans regulate blood glucose primarily via short-chain fatty acids(SCFAs)produced through gut microbiota fermentation,which directly mediate glucose homeostasis.Phenolamides accumulate via the phenylpropanoid pathway,with chalcone isomerase(CHI)serving as a key enzyme in flavonoid biosynthesis and enhancing UV-B resistance.Under low temperatures,β-glucans improve frost tolerance by modulating osmotic balance and inhibiting ice-nucleating proteins,while lipids maintain membrane fluidity to sustain cellular function during cold stress.Importantly,we explore the hypothesis that these same metabolites,upon consumption,may facilitate human adaptation to high-altitude stresses.This hypothesis is supported by preliminary epidemiological associations between Qingke consumption and favorable health outcomes in high-altitude populations,as well as established bioactivities of the implicated metabolites in vitro and in animal models.However,direct causal evidence in humans and a comprehensive understanding of the underlying molecular mechanisms remain key knowledge gaps that warrant future investigation.Qingke as a unique resource at the interface of agricultural resilience and human nutrition.Understanding its metabolic blueprint will inform the development of functional foods and climate-resilient crops.展开更多
Eospalax,one of the only two extant genera within the Myospalacinae,has a high species richness.Each species is distinguished by unique cranial and dental morphologies,as well as variations in temporal and spatial dis...Eospalax,one of the only two extant genera within the Myospalacinae,has a high species richness.Each species is distinguished by unique cranial and dental morphologies,as well as variations in temporal and spatial distribution.Consequently,Eospalax serves as a reliable indicator for the biochronologic and paleoenvironmental studies of the Quaternary of East Asia.A recent discovery of a complete fossil skull in a conglomerate deposit,a part of the Lower Pleistocene Sanmen Formation,near Jianyucha Town,Zichang County,northern Shaanxi Province,has been subjected to a detailed analysis.The specimens were identified as Eospalax simplicidens,an extinct species of Eospalax,based on dental morphology.The recent discovery of E.simplicidens in Jianyucha offers significant insights into the species’cranial morphology and contributes to a more comprehensive understanding of its geographical distribution.The distinctive feature of the posterodorsal location of the external acoustic meatus indicates either a plesiomorphy or an evolutionary convergence among E.simplicidens,African root rats(Tachyoryctes),and bamboo rats(Rhizomyini).A skull(IVPP V5398.1)and four upper jaws(V5398.2)from Gongwangling in Lantian,Shaanxi,previously identified as Myospalax fontanieri,is transferred to the species E.lingtaiensis.A skull(IVPP RV35055)from Jingou,Xin’an,Henan,previously identified as E.simplicidens,is transferred to the species E.youngianus.In this study,body mass estimates are made for extinct Eospalax.Both E.lingtaiensis and E.simplicidens are small-sized zokors,with an estimated body mass of less than or approximately 300 g,respectively.展开更多
As a critical global ecosystem,grasslands rely on complex aboveground-belowground interactions that underpin multifunctionality,yet their mechanisms remain poorly understood.Our investigation employed the plateau pika...As a critical global ecosystem,grasslands rely on complex aboveground-belowground interactions that underpin multifunctionality,yet their mechanisms remain poorly understood.Our investigation employed the plateau pika(Ochotona curzoniae),a small herbivore widely distributed throughout the Qinghai-Tibetan Plateau,as a model organism to examine the consequences of disturbance on plant diversity,soil properties,microbial diversity,and multifunctionality of grassland ecosystems.We found that high pika burrow density significantly reduced plant diversity(Shannon-Wiener and Chao1 indices)and aboveground biomass.It also increased soil pH and reduced ammonium nitrogen content.The soil microbial diversity,encompassing both bacteria and fungi,was markedly decreased in areas characterized by a high concentration of burrows.Microbial interaction networks demonstrated greater complexity in areas with high burrow densities,as revealed by the network analysis.Conversely,in regions characterized by low burrow density,a significant negative correlation was observed between the intricacy of soil bacterial networks and the multifunctionality of grassland ecosystems.Structural equation modelling showed that pika disturbance indirectly affected multifunctionality via changes in plant biomass and soil properties-notably,nitrate nitrogen explained 40%of multifunctionality variation under high disturbance.This investigation advances our understanding of complex aboveground-belowground linkages in grassland ecosystems,revealing novel mechanisms through which biodiversity governs ecosystem multifunctionality.Our findings underscore the critical role of small herbivores in shaping grassland ecosystem functions and emphasize the importance of maintaining balanced disturbance regimes to sustain ecosystem multifunctionality.This has immediate implications for global conservation policies on the Qinghai-Tibetan Plateau and analogous ecosystems.展开更多
Recent studies have suggested that rapid warming over the Mongolian Plateau(MP)may intensify extreme heat events(EHEs).However,the characteristics and mechanisms driving summer EHEs over the MP(MP-EHEs)remain unclear....Recent studies have suggested that rapid warming over the Mongolian Plateau(MP)may intensify extreme heat events(EHEs).However,the characteristics and mechanisms driving summer EHEs over the MP(MP-EHEs)remain unclear.This study explores the interannual variations in summer MP-EHEs and their relationship with the summer soil moisture over the Inner Tibetan Plateau(TP-SM).The results reveal that changes in the MP-EHEs are linked to descending atmospheric motion induced by a local high-pressure system over the MP region.Descending motion further results in decreased mid-tolow-level cloud cover and increased shortwave radiation,thereby warming the surface and triggering summer MP-EHEs.Further analysis indicates that increased TP-SM results in a greater latent heat flux,triggering a local secondary circulation that reinforces the local high-pressure system over the MP region,thus serving to promote the occurrence of summer MPEHEs.Additionally,model results from the linear baroclinic model(LBM)and CMIP6 further confirm that variations in summer TP-SM contribute to the occurrence of the MP-EHEs.展开更多
Understanding the hydrochemical dynamics of alpine arid basins is essential for ensuring sustainable water resources on the Tibetan Plateau.The Nianchu River,a typical alpine and arid basin on the Tibetan Plateau,is t...Understanding the hydrochemical dynamics of alpine arid basins is essential for ensuring sustainable water resources on the Tibetan Plateau.The Nianchu River,a typical alpine and arid basin on the Tibetan Plateau,is the focal area of the“One River,Two Tributaries”Comprehensive Development Project in Xizang Autonomous Region of China.However,no systematic studies on hydrochemistry in this basin have been conducted.This study investigated the spatio-temporal variations and controlling mechanisms of water chemistry in the Nianchu River basin with a focus on the understudied influence of widely distributed geothermal springs.During the dry and wet seasons,44 river water and 13 geothermal water samples were collected and analyzed for major ions.Results showed that the river water was weakly alkaline,with total dissolved solids and major ion concentrations(e.g.,Ca^(2+),HCO₃^(-),SO_(4)^(2-))significantly higher in the dry season(mean EC:372μS/cm)than in the wet season(mean EC:236μS/cm),and peaking in the midstream tributary of the Longma River.In contrast,the geothermal springs were moderately acidic and exhibited markedly higher mineralization(mean EC:1,936μS/cm),with Na^(+),K^(+),and Cl^(-)concentrations being 20.8,22.5,and 44.8 times those in river water,respectively.The direct discharge of geothermal water was identified as a key driver that significantly elevated Na^(+),K^(+),and Cl^(-)levels and altered the hydrochemical facies of the river in affected reaches.The main conclusions are that:(1)the hydrochemical evolution of the Nianchu River is predominantly governed by carbonate and silicate weathering,while geothermal water chemistry is controlled by evaporation-crystallization and deep water-rock interactions;and(2)sulfuric acid participates in carbonate weathering alongside carbonic acid,particularly in the mid-lower reaches,enhances the release of Ca^(2+),Mg^(2+),and SO_(4)^(2-).This study provides a holistic understanding of hydrogeochemical controls in a typical alpine basin and underscores the critical role of geothermal fluids,offering a scientific basis for protecting water resources under climate and anthropogenic pressures.展开更多
Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance com...Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance components have advanced,persistent biases remain due to the independent development of datasets,impacting basin scale water budget balance.In this research,we analyzed the mathematical origin of the bias between water budget components and developed a new basin-scale water balance calibration method that redistributes errors across components while enforcing water balance constraints.Validation confirms systematic improvements,with reduced RMSE(Precipitation:-2.29 mm/month;ET:-1.34 mm/month)and increased R2 against in situ observations.Applied to the Jinghe River Basin(2000−2019),the calibrated data reveal declining precipitation(-1.70 mm/year)and evapotranspiration(-1.84 mm/year)alongside slightly increasing runoff(0.20 mm/year in basin depth),signaling a drying trend.Land cover changes—marked by cropland loss(-3,497 km^(2))and forest(+720 km^(2))and grassland(+2,776 km^(2))expansion—reflect improved water consumption requirements by ecosystem,raising concerns for water retention and ecosystem stability.The method is particularly effective for ungauged basins with sparse ground data and underscores the need for integrated land-water management to enhance long-term resilience.展开更多
With the advancement of the Belt and Road Initiative and increasing activity in high-altitude regions,the incidence of high-altitude-related diseases has steadily increased.Notably,the prevention and treatment of high...With the advancement of the Belt and Road Initiative and increasing activity in high-altitude regions,the incidence of high-altitude-related diseases has steadily increased.Notably,the prevention and treatment of high-altitude brain injuries remain particularly challenging,making them a key focus of current medical research.The low-pressure and low-oxygen environments at high altitudes significantly increase the risk of hypoxic brain injury.Consequently,understanding the mechanisms that drive these injuries and developing targeted treatments are crucial for maintaining the health of individuals who rapidly ascend to high altitudes.This review examines the mechanisms underlying high-altitude brain injury,outlines the development and evaluation of commonly used animal models for altitude stress,and explores potential therapeutic approaches to support effective prevention and treatment strategies for these conditions.展开更多
文摘The depositional environment of the sands of the cover formation is discussed. This study aims to determine the paleoenvironments of deposition of the sands of the cover formation in the Batéké Plateaus by studying sedimentary dynamics based on the description of lithological facies in the field and granulometric analyses in the laboratory. In the field, six (6) lithostratigraphic logs were surveyed and 42 sand samples were taken for laboratory analysis. In the laboratory, the samples underwent granulometric, sieving and sedimentometry analyses, after washing with running water using a 63 µm sieve. These analyses made it possible to determine the granulometric classes of the samples. The sieving results allowed to determine the granulometric parameters (mean, standard deviation, mode, median, skewness, flattening or kurtosis) using the method of moments with the software “Gradistat V.8”, granulometric parameters with which the granulometric facies, the mode of transport and the deposition environment were determined using the diagrams. Morphoscopy made it possible to determine the form and aspect of the surface of the quartz grains constituting these sands. Granulometric analyses show that these silty-clay or clayey-silty sands are fine sands and rarely medium sands, moderately to well sorted and rarely well sorted. The dominant granulometric facies is hyperbolic (sigmoid), with parabolic facies being rare. The primary mode of transport of these sands is saltation, which dominates rolling. The dispersion of points in the diagrams shows that these sands originate from two depositional environments: aeolian and fluvial. Morphoscopic analysis reveals the presence of clean rounded matt grains (RM), dirty rounded matt grains (RS), shiny blunt grains (EL) and shiny rounded grains (RL). The rounded matt grains exhibit several impact marks. The presence of dirty rounded grains with a ferruginous cement on their surface indicates that these sands have been reworked. These sands have undergone two types of transport, first by wind (aeolian environment) and then by water (fluvial environment).
基金supported by the National Natural Science Foundation of China (Grant Nos.91437219,41275075 and 41175005)the National Basic Research Program of China (Grant No.2013CB430203)
文摘Variation in the location of the South Asian High （SAH） in early boreal summer is strongly influenced by elevated surface heating from the Tibetan Plateau （TP） and the Iranian Plateau （IP）. Based on observational and ERA-Interim data, diagnostic analyses reveal that the interannual northwestward-southeastwaxd （NW-SE） shift of the SAH in June is more closely correlated with the synergistic effect of concurrent surface thermal anomalies over the TP and IP than with each single surface thermal anomaly over either plateau from the preceding May. Concurrent surface thermal anomalies over these two plateaus in May are characterized by a negative correlation between sensible heat flux over most parts of the TP （TPSH） and IP （IPSH）. This anomaly pattern can persist till June and influences the NW-SE shift of the SAH in June through the release of latent heat （LH） over northeastern India. When the IPSH is stronger （weaker） and the TPSH is weaker （stronger） than normal in May, an anomalous cyclone （anticyclone） appears over northern India at 850 hPa, which is accompanied by the ascent （descent） of air and anomalous convergence （divergence） of moisture flux in May and June. Therefore, the LH release over northeastern India is strengthened （weakened） and the vertical gradient of apparent heat source is decreased （increased） in the upper troposphere, which is responsible for the northwestward （southeastward） shift of the SAH in June.
基金supported by the National Key R&D Program of China (No. 2018YFC0309800)the National Natural Science Foundation of China (Nos. 91628301, U1606401, 41606069, 41776058)+2 种基金the Natural Science Foundation of Guangdong Province in China (No. 2017A030313243)the Chinese Academy of Sciences (Nos. Y4SL021001, QYZDY-SSWDQC005)the China Association of Marine Affairs (No. CAMAZD201714)
文摘Oceanic plateaus are large igneous provinces in the oceans,created by massive underwater eruptions,but their late-stage volcanism is poorly understood.With the addition of recent high-quality bathymetric data to existing data,286 secondary cones were discovered over Shatsky Rise oceanic plateau.These cones with steeper flank slopes(mean 6.1°±4.4°)and smaller sizes(102–1923 m in height)are morphologically distinct from the plateau,and they are thought to have formed after the main volcanic episodes.Cone height and characteristic height(420 m)are close to seamounts in the Pacific Ocean,whereas greater than those in the Atlantic Ocean.Mean flatness of Shatsky Rise’s cones(0.25±0.20)are similar to that of seamounts in both Pacific and Atlantic Oceans,but notably density in cone distribution(0.56 km^-3)and their mean slope are significantly lower than those of seamounts in the two oceans.Lower slopes of secondary cones within Shatsky Rise may be explained by higher effusion rates of remaining magma.Although cone formation was expected to have a link to rifting by seafloor spreading,weak relationship between cone orientation and magnetic anomaly pattern implies that the expectation is negative.Moreover,weak correlation between the cone height and depth indicates it is not true that volcanic cones grow taller when they occur closer to the massif summits with thicker oceanic crust,which was suggested as the increase in hydraulic pressure.Cone height and flatness are also not strongly related,implying that remaining magma supply was too limited to foster the cones to critical height.
文摘Taking Niyang River Basin as an example, applying with the indices of landscape pattern, the indices of ecological risk of ecosystems are calculated in this paper, which takes the value of ecological loss of main ecosystem as the evaluation standard and takes into account the impacts of probability or the velocity of main hazards and event of the ecosystem. And the grades of ecological risk are assessed. According to the results of assessment, the ecological risk grades of the basin are divided into five classes. From the first grade risk to the fifth grade risk, the values of regional risk indices gradually reduce. The first grade risk areas mainly distribute in Niyang river and its branches downstream and the surrounding areas of main towns. And the basin area of non-valley region and the headstream regions of the branches are the fifth grades risk areas. This evaluation results provide the basis to the regional sustainable development.
基金supported by the National Natural Science Foundation of China(Grant Nos.41871350,41571099)the Scientific and Technological Basic Resources Survey Project(Grant No.2017FY100900)。
文摘As one of the main non-zonal factors,the mass elevation effect(MEE)has significant impacts on both regional climates and mountain ecological patterns.In recent years,with the development of quantitative techniques and methods,quantitative studies on the MEE and its implication on mountain altitudinal belts have developed rapidly.However,some issues have not been solved yet,such as high errors in spatial temperature estimations and difficulties in the definition and extraction of intramountain base elevation.Moreover,there is still a lack of comparative studies on the MEE and its influence on treelines and snowlines as most studies were conducted on specific mountains or plateaus.To compare the MEE magnitudes of the Tibetan Plateau(TP)and the Bolivian Plateau(BP),we estimated the correspondent air temperatures and simulated the solar radiations based on MODIS surface temperature,station observation,and treeline data.Then,we analyzed the elevation of the 10℃isotherms on the two plateaus,the temperatures at the same elevation,and the solar radiations.According to the mechanism of the MEE and the relationship of solar radiation and treeline,we constructed treeline models for the two plateaus through a stepwise regression analysis by considering several influencing factors of the MEE(e.g.,air temperature and precipitation)and using solar radiation as its proxy.The results showed that:(1)the MEE magnitude on the TP is equivalent to that on the BP although the former is slightly higher than the latter;(2)the MEE strongly influences the highest treelines in the northern and southern hemispheres,which both occur on the two plateaus.Notably,the treeline distribution models based on solar radiation had higher accuracies than those models with parameters of temperature and precipitation(the adjusted R^(2)values were 0.76 for the TP and 0.936 for the BP),indicating that solar radiation can be used to quantify the MEE and its implications on treelines.Overall,the results of this study can serve as a basis for subsequent analyses on the MEE’s impact factors.
文摘In southern Asia,there are three large-scale wave-like mountains ranging from the Tibetan Plateau westward to the Iranian Plateau and the Armenian Plateau.On the southern side between plateaus,there are the Indian Peninsula and the Arabian Peninsula.What dynamic mechanisms form the directional alignment of the three plateaus with the two peninsulas remains a mystery.In the early stages of the Earth’s geological evolution,the internal structure of the Earth was that the center was a solid core,and the outmost layer was a thin equatorial crust zone separated by two thick pristine continents in polar areas,while the middle part was a deep magma fluid layer.Within the magma fluid layer,thermal and dynamic differences triggered planetary-scale vertical magma cells and led to the core-magma angular momentum exchange.When the core loses angular momentum and the magma layer gains angular momentum,the movement of upper magma fluids to the east and the tropical convergence zone(TCZ)drives the split and drift of two thick pristine continents,eventually forming the current combination of these plateaus and peninsulas and their wave-like arrangement along the east-west direction.Among them,the horizontal orthogonal convergence(collision)of upper magma fluids from the two hemispheres excited the vertical shear stress along the magma TCZ,which is the dynamic mechanism of mountain uplifts on the north side and plate subductions on the south side.To confirm this mechanism,two examples of low-level winds are used to calculate the correspondence between cyclone/anticyclonic systems generated by the orthogonal collision of airflows along the atmospheric TCZ and satellite-observed cloud systems.Such comparison can help us revisit the geological history of continental drift and orogeny.
文摘Cryogenic wedges developed due to very cold,rather arid conditions during the maximum of the last cold event when the drying up of the neighboring China Sea resulted in the failure of the East Asian Monsoon.As the climate ameliorated and the Monsoon rains reappeared,ice-wedges developed.Further warming permitted thawing of the ice infillings accompanied by replacement of the ice by sediments partly from the host ground as well as from the surface by wind or sheet wash.In cases of extreme surface water flow on slopes after 10 ka B.P.,small baydjarakhs typically c.50 cm high developed,only to have the resulting hollows infilled by sediments carried by wind and/or sheet wash.These shallow structures form a network on top of many of the cryogenic wedges.This complex history makes dating the ages of the wedges difficult using OSL methodology.Unfortunately,past field work ignored the problem of the angle of the cut face to the direction of the wedge infilling when sampling the contents of the narrow wedges,resulting in potential contamination of the samples with the host sediment.Sampling of the larger deposits should be alright,but the likelihood of contamination makes the interpretation of the resulting OSL dates from the narrow wedges questionable.Primary wedges consisting of primary mineral infillings should still have similar OSL dates with depth for a given wedge,but the distinction between ice-wedge infillings and soil wedges is difficult since both can exhibit older dates of the infillings with depth.The available data suggests that ice-wedges were significantly more common than sediment-filled primary wedges.A protocol to avoid having to obtain large numbers of OSL dates by more careful field sampling and the use of grain size determinations is provided in the Appendix.
基金supported by National Key Projects for Research and Development of China(No.2021YFA1400400 and No.2024YFA1408104)the National Natural Science Foundation of China(No.12374137,No.12434005,No.92165205,and No.12074175).
文摘The kagome lattice,with its unique geometric structure,has emerged as a leading platform for exploring quantum many-body physics,particularly in the study of quantum spin liquids(QSLs)and unconventional superconductivity.This review highlights recent advancements in the investigations of QSLs,fractional magnetization plateau phases in kagome antiferromagnets,and unconventional superconductivity in vanadium-based kagome superconductors.We begin by examining the classical ground-state properties of the nearest-neighbor kagome antiferromagnetic Heisenberg model and introducing recent experimental progress in the study of QSLs and fractional magnetization plateau phases.Next,we discuss the fermionic description of the QSL states,along with related gauge theory and the variational Monte Carlo(VMC)method.We then focus on discussing the VMC studies of QSLs and magnetization plateau phases in kagome antiferromagnets.For superconductivity in kagome systems,we first analyze the characteristics of the electronic structure and the possible associated electronic instabilities.Finally,we review recent experimental advances in unconventional superconductivity in AV_(3)Sb_(5)(A=K,Rb,Cs),with a particular focus on chiral superconductivity and pairing density waves.
文摘Osteoarthritis(OA)is a degenerative skeletal condition marked by the loss of articular cartilage and changes to subchondral bone homeostasis.Treatments for OA beyond full joint replacement are lacking primarily due to gaps in molecular knowledge of the biological drivers of disease.Mass Spectrometry Imaging(MSI)enables molecular spatial mapping of the proteomic landscape of tissues.Histologic sections of human tibial plateaus from knees of human OA patients and cadaveric controls were treated with collagenase Ⅲ to target extracellular matrix(ECM)proteins prior to MS Imaging of bone and cartilage proteins.Spatial MS imaging of the knee identified distinct areas of joint damage to the subchondral bone underneath areas of lost cartilage.This damaged bone signature extended underneath remaining cartilage in OA joints,indicating subchondral bone remodeling could occur before full thickness cartilage loss in OA.Specific ECM peptide markers from OA-affected medial tibial plateaus were compared to their healthier lateral halves from the same patient,as well as to healthy,age-matched cadaveric knees.Overall,31 peptide candidates from ECM proteins,including Collagen alpha-1(Ⅰ),Collagen alpha-1(Ⅲ),and surprisingly,Collagen alpha-1(Ⅵ)and Collagen alpha-3(Ⅵ),exhibited significantly elevated abundance in diseased tissues.Additionally,highly specific hydroxyproline-containing collagen peptides,mainly from collagen typeⅠ,dominated OA subchondral bone directly under regions of lost cartilage but not areas where cartilage remained intact.A separate analysis of synovial fluid from a second cohort of OA patients found similar regulation of collagens and ECM proteins via LC-MS/MS demonstrating that markers of subchondral bone remodeling discovered by MALDI-MS may be detectable as biomarkers in biofluid samples.The identification of specific protein markers for subchondral bone remodeling in OA advances our molecular understanding of disease progression in OA and provides potential new biomarkers for OA detection and disease grading.
基金The national research foundation of Singapore(NRF-P2024-001).
文摘Variational quantum algorithms(VQAs)with random structures have poor trainability due to the exponentially vanishing gradient as the circuit depth and the qubit number increase.This result leads to a general belief that a deep circuit will not be feasible.In this work,we provide a viable solution to the vanishing gradient problem for deep VQAs with theoretical guarantees.Specifically,we prove that for quantum controlled-layer and quantum residual network(QResNet),architectures,the expectation of the gradient norm can be lower bounded by a value that is independent of the qubit number and the circuit depth.Our results follow from a careful analysis of the gradient behavior on parameter space consisting of rotation angles,as employed in almost all VQAs,instead of relying on impractical 2-design assumptions.We conduct several numerical experiments as verifications,where only our circuits are trainable and converge,while hardware-efficient and random circuits with similar number of parameters in comparison cannot converge.
基金supported by SOA Funds for Young Scientists(Grant Nos.1084-10)Special Funding for the Basic Scientific Research(Grant Nos.JG0706and JG0716)
文摘This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian Ocean.We first calculated the relative distance between the Southwest Indian Ridge(SWIR)and relevant hotspots on the basis of models of plate reconstruction,and then calculated the corresponding excess magmatic anomalies of the hotspots on the basis of residual bathymetry and Airy isostasy.The results reveal that the activities of the Marion hotspot can be divided into three main phases:interaction with the paleo-Rodrigues triple junction(73.6-68.5 Ma),interaction with the SWIR(68.5-42.7 Ma),and intra-plate volcanism(42.7-0 Ma).These three phases correspond to the formation of the eastern,central,and western parts of the Del Cano Rise,respectively.The magnitude and apparent periodicity of the magmatic volume flux of the Marion hotspot appear to be dominated by the hotspot-ridge distance.The periodicity of the Marion hotspot is about 25 Ma,which is much longer than that of the Hawaii and Iceland hotspots(about 15 Ma).
基金supported by the Financial Special Fund,grant number XZ202401JD0027National Barley Industry Technology System(CARS-05-01A-08)+3 种基金the Xizang Agri-Tech Innovation Project(XZNKY-2025-CXGC-T01)the Joint Funds of the National Natural Science Foundation of China(No.U20A2026)the Financial Special Fund,grant number(32401784,2017CZZX001/2,XZNKY-2018-C-021 and NYSTC202401)the China Agriculture Research System of Barley(CARS-05).
文摘Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that confer cold and UV resistance on the crop also facilitate human adaptation to high-altitude stresses.Specifically,β-glucans regulate blood glucose primarily via short-chain fatty acids(SCFAs)produced through gut microbiota fermentation,which directly mediate glucose homeostasis.Phenolamides accumulate via the phenylpropanoid pathway,with chalcone isomerase(CHI)serving as a key enzyme in flavonoid biosynthesis and enhancing UV-B resistance.Under low temperatures,β-glucans improve frost tolerance by modulating osmotic balance and inhibiting ice-nucleating proteins,while lipids maintain membrane fluidity to sustain cellular function during cold stress.Importantly,we explore the hypothesis that these same metabolites,upon consumption,may facilitate human adaptation to high-altitude stresses.This hypothesis is supported by preliminary epidemiological associations between Qingke consumption and favorable health outcomes in high-altitude populations,as well as established bioactivities of the implicated metabolites in vitro and in animal models.However,direct causal evidence in humans and a comprehensive understanding of the underlying molecular mechanisms remain key knowledge gaps that warrant future investigation.Qingke as a unique resource at the interface of agricultural resilience and human nutrition.Understanding its metabolic blueprint will inform the development of functional foods and climate-resilient crops.
文摘Eospalax,one of the only two extant genera within the Myospalacinae,has a high species richness.Each species is distinguished by unique cranial and dental morphologies,as well as variations in temporal and spatial distribution.Consequently,Eospalax serves as a reliable indicator for the biochronologic and paleoenvironmental studies of the Quaternary of East Asia.A recent discovery of a complete fossil skull in a conglomerate deposit,a part of the Lower Pleistocene Sanmen Formation,near Jianyucha Town,Zichang County,northern Shaanxi Province,has been subjected to a detailed analysis.The specimens were identified as Eospalax simplicidens,an extinct species of Eospalax,based on dental morphology.The recent discovery of E.simplicidens in Jianyucha offers significant insights into the species’cranial morphology and contributes to a more comprehensive understanding of its geographical distribution.The distinctive feature of the posterodorsal location of the external acoustic meatus indicates either a plesiomorphy or an evolutionary convergence among E.simplicidens,African root rats(Tachyoryctes),and bamboo rats(Rhizomyini).A skull(IVPP V5398.1)and four upper jaws(V5398.2)from Gongwangling in Lantian,Shaanxi,previously identified as Myospalax fontanieri,is transferred to the species E.lingtaiensis.A skull(IVPP RV35055)from Jingou,Xin’an,Henan,previously identified as E.simplicidens,is transferred to the species E.youngianus.In this study,body mass estimates are made for extinct Eospalax.Both E.lingtaiensis and E.simplicidens are small-sized zokors,with an estimated body mass of less than or approximately 300 g,respectively.
基金supported by the National Natural Science Foundation of China(32471603)Science and Technology Commissioner Special Project of Qinghai Province(2025-NK-P42)+2 种基金Central Financial Funds for Forestry and Grassland Reform and Development in 2024(2024-TG16)Hainan Tibetan Autonomous Prefecture Science and Technology Program Project(2025-KH01-B)the leading Kunlun talents in Qinghai Province.
文摘As a critical global ecosystem,grasslands rely on complex aboveground-belowground interactions that underpin multifunctionality,yet their mechanisms remain poorly understood.Our investigation employed the plateau pika(Ochotona curzoniae),a small herbivore widely distributed throughout the Qinghai-Tibetan Plateau,as a model organism to examine the consequences of disturbance on plant diversity,soil properties,microbial diversity,and multifunctionality of grassland ecosystems.We found that high pika burrow density significantly reduced plant diversity(Shannon-Wiener and Chao1 indices)and aboveground biomass.It also increased soil pH and reduced ammonium nitrogen content.The soil microbial diversity,encompassing both bacteria and fungi,was markedly decreased in areas characterized by a high concentration of burrows.Microbial interaction networks demonstrated greater complexity in areas with high burrow densities,as revealed by the network analysis.Conversely,in regions characterized by low burrow density,a significant negative correlation was observed between the intricacy of soil bacterial networks and the multifunctionality of grassland ecosystems.Structural equation modelling showed that pika disturbance indirectly affected multifunctionality via changes in plant biomass and soil properties-notably,nitrate nitrogen explained 40%of multifunctionality variation under high disturbance.This investigation advances our understanding of complex aboveground-belowground linkages in grassland ecosystems,revealing novel mechanisms through which biodiversity governs ecosystem multifunctionality.Our findings underscore the critical role of small herbivores in shaping grassland ecosystem functions and emphasize the importance of maintaining balanced disturbance regimes to sustain ecosystem multifunctionality.This has immediate implications for global conservation policies on the Qinghai-Tibetan Plateau and analogous ecosystems.
基金supported by the National Natural Science Foundation of China(Grant No.42288101)the Young Scientists Fund of the National Natural Science Foundation of China(Grand No.42505018)the Shanghai“Science and Technology Innovation Action Plan”Venus Project(Grant No.23YF1437300)。
文摘Recent studies have suggested that rapid warming over the Mongolian Plateau(MP)may intensify extreme heat events(EHEs).However,the characteristics and mechanisms driving summer EHEs over the MP(MP-EHEs)remain unclear.This study explores the interannual variations in summer MP-EHEs and their relationship with the summer soil moisture over the Inner Tibetan Plateau(TP-SM).The results reveal that changes in the MP-EHEs are linked to descending atmospheric motion induced by a local high-pressure system over the MP region.Descending motion further results in decreased mid-tolow-level cloud cover and increased shortwave radiation,thereby warming the surface and triggering summer MP-EHEs.Further analysis indicates that increased TP-SM results in a greater latent heat flux,triggering a local secondary circulation that reinforces the local high-pressure system over the MP region,thus serving to promote the occurrence of summer MPEHEs.Additionally,model results from the linear baroclinic model(LBM)and CMIP6 further confirm that variations in summer TP-SM contribute to the occurrence of the MP-EHEs.
基金jointly funded by the School Scientific Research Development Fund project(2022LFR091)。
文摘Understanding the hydrochemical dynamics of alpine arid basins is essential for ensuring sustainable water resources on the Tibetan Plateau.The Nianchu River,a typical alpine and arid basin on the Tibetan Plateau,is the focal area of the“One River,Two Tributaries”Comprehensive Development Project in Xizang Autonomous Region of China.However,no systematic studies on hydrochemistry in this basin have been conducted.This study investigated the spatio-temporal variations and controlling mechanisms of water chemistry in the Nianchu River basin with a focus on the understudied influence of widely distributed geothermal springs.During the dry and wet seasons,44 river water and 13 geothermal water samples were collected and analyzed for major ions.Results showed that the river water was weakly alkaline,with total dissolved solids and major ion concentrations(e.g.,Ca^(2+),HCO₃^(-),SO_(4)^(2-))significantly higher in the dry season(mean EC:372μS/cm)than in the wet season(mean EC:236μS/cm),and peaking in the midstream tributary of the Longma River.In contrast,the geothermal springs were moderately acidic and exhibited markedly higher mineralization(mean EC:1,936μS/cm),with Na^(+),K^(+),and Cl^(-)concentrations being 20.8,22.5,and 44.8 times those in river water,respectively.The direct discharge of geothermal water was identified as a key driver that significantly elevated Na^(+),K^(+),and Cl^(-)levels and altered the hydrochemical facies of the river in affected reaches.The main conclusions are that:(1)the hydrochemical evolution of the Nianchu River is predominantly governed by carbonate and silicate weathering,while geothermal water chemistry is controlled by evaporation-crystallization and deep water-rock interactions;and(2)sulfuric acid participates in carbonate weathering alongside carbonic acid,particularly in the mid-lower reaches,enhances the release of Ca^(2+),Mg^(2+),and SO_(4)^(2-).This study provides a holistic understanding of hydrogeochemical controls in a typical alpine basin and underscores the critical role of geothermal fluids,offering a scientific basis for protecting water resources under climate and anthropogenic pressures.
基金supported by the National Key Research and Development Program of China(Grants No.2024YFF0810500 and 2022YFD1900802)the National Natural Scientific Foundations of China(Grants No.41991232,42301016 and 42571034)the Hainan Provincial Natural Science Foundation of China(Grant No.424QN354).
文摘Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance components have advanced,persistent biases remain due to the independent development of datasets,impacting basin scale water budget balance.In this research,we analyzed the mathematical origin of the bias between water budget components and developed a new basin-scale water balance calibration method that redistributes errors across components while enforcing water balance constraints.Validation confirms systematic improvements,with reduced RMSE(Precipitation:-2.29 mm/month;ET:-1.34 mm/month)and increased R2 against in situ observations.Applied to the Jinghe River Basin(2000−2019),the calibrated data reveal declining precipitation(-1.70 mm/year)and evapotranspiration(-1.84 mm/year)alongside slightly increasing runoff(0.20 mm/year in basin depth),signaling a drying trend.Land cover changes—marked by cropland loss(-3,497 km^(2))and forest(+720 km^(2))and grassland(+2,776 km^(2))expansion—reflect improved water consumption requirements by ecosystem,raising concerns for water retention and ecosystem stability.The method is particularly effective for ungauged basins with sparse ground data and underscores the need for integrated land-water management to enhance long-term resilience.
基金financially supported by Beijing Natural Science Foundation(L232085,L222126).
文摘With the advancement of the Belt and Road Initiative and increasing activity in high-altitude regions,the incidence of high-altitude-related diseases has steadily increased.Notably,the prevention and treatment of high-altitude brain injuries remain particularly challenging,making them a key focus of current medical research.The low-pressure and low-oxygen environments at high altitudes significantly increase the risk of hypoxic brain injury.Consequently,understanding the mechanisms that drive these injuries and developing targeted treatments are crucial for maintaining the health of individuals who rapidly ascend to high altitudes.This review examines the mechanisms underlying high-altitude brain injury,outlines the development and evaluation of commonly used animal models for altitude stress,and explores potential therapeutic approaches to support effective prevention and treatment strategies for these conditions.
