Elevation patterns and assembly processes of soil microbial community structures are essential for understanding biogeo-chemical processes in mountain systems.Differences in soil properties caused by elevation gradien...Elevation patterns and assembly processes of soil microbial community structures are essential for understanding biogeo-chemical processes in mountain systems.Differences in soil properties caused by elevation gradients can regulate the spatial distribu-tion and network complexity of the community structure.To explore the variations in soil microbial community structures and their as-sembly mechanisms across different elevations of the Changbai Mountains,as well as their responses to environmental factors,we col-lected microbial samples along an elevational gradient(seven elevations containing four vegetation zones)on the western slope of the Changbai Mountains using the method of metagenomic sequencing.The results showed a significant difference(P<0.05)for the Chao1 index across different elevations,but no significant difference was observed for the Shannon and Simpson indices.With increasing elev-ation,the number of nodes and links in the microbial network gradually decreased.Acidobacteria were highly connected to many nodes.The microbial communities indicated a significant distance-decay relationship(P<0.001)and were affected more by stochastic pro-cesses along the elevation gradient.The results of the Structural Equation Model(SEM)showed that elevation had direct significant ef-fect on carbon(C,P<0.01),nitrogen(N,P<0.01),and phosphorus(P,P<0.05)and weak negative effect on their ecological stoi-chiometry.Elevation was one of the major variables contributing to microbial network topology.The contribution of C and N to micro-bial network complexity was higher than that of P.Our study provides valuable insights into the responses of soil microbial communit-ies to elevation variations.展开更多
The infrared channels of the FY-4B advanced geosynchronous radiation imagers(AGRI) play a crucial role in temperature and humidity analyses for mesoscale numerical weather prediction, particularly in enhancing the ini...The infrared channels of the FY-4B advanced geosynchronous radiation imagers(AGRI) play a crucial role in temperature and humidity analyses for mesoscale numerical weather prediction, particularly in enhancing the initial field quality and the forecasting accuracy of the model. This study assimilated FY-4B AGRI data into the CMA-MESO model and analyzed the bias characteristics and correction methods. Analysis of the AGRI data revealed a clear diurnal variation in the bias, which was positively correlated with the solar elevation angle. However, the diurnal variation in the bias lagged behind the solar elevation angle, likely owing to temperature changes and delayed instrument responses resulting from solar radiation. To address this issue, we propose a correction method that utilizes the solar elevation angle after an optimal time shift. Using the time-shifted solar elevation angle as a predictor effectively reduces the diurnal variation in bias and significantly improves the correction effect. This approach provides theoretical support for the assimilation of FY-4B AGRI data into mesoscale numerical weather predictions, thereby enhancing the reliability of the assimilation results.展开更多
Dear Editor,Mountain systems have long been refuges for many species,often viewed as"islands"that promote speciation due to geographic isolation(Rahbek et al.,2019).Their high environmental heterogeneity fos...Dear Editor,Mountain systems have long been refuges for many species,often viewed as"islands"that promote speciation due to geographic isolation(Rahbek et al.,2019).Their high environmental heterogeneity fosters centers of endemism,and they harbor over 85%of global species diversity(Zhao et al.,2022).Consequently,mountains are key systems for exploring biodiversity patterns along elevational gradients,where species richness often follows four recognized models:monotonic decrease,unimodal pattern(forward and backward peak patterns),and low plateau followed by a decrease along the elevational gradient(McCain et al.,2010).展开更多
Mountain ecosystems offer natural gradients for exploring biodiversity patterns;however,the elevational patterns of plant species and phylogenetic diversity in the eastern Pamir Plateau remain poorly understood.As a b...Mountain ecosystems offer natural gradients for exploring biodiversity patterns;however,the elevational patterns of plant species and phylogenetic diversity in the eastern Pamir Plateau remain poorly understood.As a biogeographical junction of the Central Asian mountain ranges,the eastern Pamir Plateau in China is geographically connected to the main part of the Pamir Plateau in Tajikistan,resulting in significant climatic and topographical heterogeneity and unique regional vegetation communities.In this study,we established 5 elevational transects and 91 plots (1500–4870 m) in the eastern Pamir Plateau to investigate the patterns and environmental drivers of plant diversity at both regional and local spatial scales.We examined diversity patterns and community composition using regression models and community structure analysis and quantified the relative importance of environmental factors using a random forest model.The results showed a distinct differentiation along elevation gradients,with overall plant diversity,herbaceous plant diversity,and phylogenetic diversity index increasing with elevation,whereas woody plant diversity declined.The phylogenetic structure indices (including net relatedness index and nearest taxon index) exhibited heterogeneous elevational responses,indicating that community assembly was jointly driven by environmental filtering and niche differentiation.Soil nutrients,water availability,and temperature were the primary environmental drivers,with soil factors predominantly influencing herbaceous plant diversity,while climatic variables dominated woody plant diversity.These findings demonstrate that plant diversity along elevational gradients of the eastern Pamir Plateau exhibits the characteristic patterns of a unique arid mountain ecosystem,where enhanced soil fertility and moderate moisture at higher elevations partly offset energy limitations,thereby maintaining plant diversity through functional convergence of closely related lineages.This pattern of biodiversity maintenance contrasts with the divergence-driven community assembly processes commonly observed in humid mountain systems.Overall,this study contributes to a better understanding of biodiversity maintenance in the eastern Pamir Plateau.Given its geographical continuity with the Pamir Plateau in Tajikistan,our findings can provide a basis for alpine conservation efforts across arid Central Asia.展开更多
Dear Editor,Understanding patterns of species diversity is a primary research focus in macroecology,with its distribution patterns having been described and theoretically validated on a global scale(Peters et al.,2016...Dear Editor,Understanding patterns of species diversity is a primary research focus in macroecology,with its distribution patterns having been described and theoretically validated on a global scale(Peters et al.,2016;Sonne et al.,2025).Numerous studies have found that species richness of different taxa tends to decrease with increasing elevation and is modulated by latitudinal gradients(Peters et al.,2016;Dolson et al.,2024).This principle provides a crucial scientific basis for regional conservation planning.However,it still exhibits significant variations across different mountain ranges and taxa.展开更多
Forests exert significant biogeophysical cooling effects(CE)through processes such as increased evapotranspiration,reduced albedo,and enhanced surface roughness.However,little is known about the extent to which elevat...Forests exert significant biogeophysical cooling effects(CE)through processes such as increased evapotranspiration,reduced albedo,and enhanced surface roughness.However,little is known about the extent to which elevation-induced temperature differences bias the observed CE and how this bias interacts with the underlying biogeophysical mechanisms.In this study,we integrated multisensor remote sensing products and Shuttle Radar Topography Mission(SRTM)elevation data on the Google Earth Engine(GEE)platform,and applied a spatial-temporal window regression approach to quantify and correct the sensitivity of land surface temperature(LST)to elevation for forest pixels across China from 2001 to 2022.First,we found that forest LST exhibited a significant negative relationship with elevation,leading to systematic CE overestimation by 0.61 K during the day and 0.60 K at night compared with altitudecorrected CE values.Second,after correction,the CE showed clear spatial heterogeneity,with stronger daytime cooling in tropical(-0.54 K)and temperate forests(-0.24 K),and warming in cold(+0.11 K)and arid regions(+0.53 K),while most regions experienced nighttime warming.Among forest types,evergreen needleleaf forests(ENF)exhibited the strongest daytime cooling(-0.36 K),whereas deciduous broadleaf(DBF)and open shrublands(OS)tended to warm.Third,mechanism analysis revealed that elevation correction strengthened the correlations of CE with leaf area index(LAI)and evapotranspiration,while maintaining a significant negative correlation with albedo,indicating that both radiative and non-radiative processes jointly shape the unbiased CE.These findings provide a more accurate quantification of forest CE by eliminating elevation-induced bias,which providing a more accurate assessment of the climate mitigation potential of forests,which is crucial for developing more effective forest management and ecological restoration strategies.展开更多
Understanding how and why assemblage dissimilarity changes along spatial gradient is a great challenge in ecology,because answers to these questions depend on the analytical types,dimensions,and components of beta div...Understanding how and why assemblage dissimilarity changes along spatial gradient is a great challenge in ecology,because answers to these questions depend on the analytical types,dimensions,and components of beta diversity we concerned.To obtain a comprehensive understanding of assemblage dissimilarity and its implications for biodiversity conservation in the Himalayas,we explored the elevational patterns and determinants of beta diversity and its turnover and nestedness components of pairwise and multiple types and taxonomic and phylogenetic dimensions simultaneously.Patterns of beta diversity and their components of different types and dimensions were calculated based on 96 sampling quadrats along an 1800-5400 m elevational gradient.We examined whether and how these patterns differed from random expectations using null models.Furthermore,we used random forest methods to quantify the role of environmental variables representing climate,topography,and human disturbance in determining these patterns.We found that beta diversity and its turnover component,regardless of its types and dimensions,shown a hump-shaped elevational patterns.Both pairwise and multiple phylogenetic beta diversity were remarkably lower than their taxonomic counterpart.These patterns were significantly less than random expectation and were mostly associated with climate variables.In summary,our results suggested that assemblage dissimilarity of seed plants was mostly originate from the replacement of closely related species determined by climate-driven environmental filtering.Accordingly,conservation efforts should better cover elevations with different climate types to maximalize biodiversity conservation,rather than only focus on elevations with highest species richness.Our study demonstrated that comparisons of beta diversity of different types,dimensions,and components could be conductive to consensus on the origin and mechanism of assemblage dissimilarity.展开更多
BACKGROUND The incidence of acute myocardial infarction(AMI)is rising,with cardiac rupture accounting for approximately 2%of deaths in patients with acute ST-segment elevation myocardial infarction(STEMI).Ventricular ...BACKGROUND The incidence of acute myocardial infarction(AMI)is rising,with cardiac rupture accounting for approximately 2%of deaths in patients with acute ST-segment elevation myocardial infarction(STEMI).Ventricular free wall rupture(FWR)occurs in approximately 2%of AMI patients and is notably rare in patients with non-STEMI.Types of cardiac rupture include left ventricular FWR,ventricular septal rupture,and papillary muscle rupture.The FWR usually leads to acute cardiac tamponade or electromechanical dissociation,where standard resuscitation efforts may not be effective.Ventricular septal rupture and papillary muscle rupture often result in refractory heart failure,with mortality rates over 50%,even with surgical or percutaneous repair options.CASE SUMMARY We present a rare case of an acute non-STEMI patient who suffered sudden FWR causing cardiac tamponade and loss of consciousness immediate before undergoing coronary angiography.Prompt resuscitation and emergency open-heart repair along with coronary artery bypass grafting resulted in successful patient recovery.CONCLUSION This case emphasizes the risks of AMI complications,shares a successful treatment scenario,and discusses measures to prevent such complications.展开更多
Allium stracheyi(Baker)is widely utilized as a culinary herb and is typically encountered in the higher elevations of the Himalayas.Consequently,it is of great significance to compare the ecological adaptability of th...Allium stracheyi(Baker)is widely utilized as a culinary herb and is typically encountered in the higher elevations of the Himalayas.Consequently,it is of great significance to compare the ecological adaptability of this indigenous species to alternative habitats and its introduction into new environments.This research aims to investigate and gain a comprehensive understanding of A.stracheyi,also known as faran,in Uttarakhand region.We aim to examine how this plant adapts morphologically,physiologically,biochemically,and anatomically to varying elevations,specifically at 550,2200,2460,and 3400 m above mean sea level(m AMSL).This plant demonstrated remarkable morphophysiological adjustments across various aspects of its development,encompassing modified growth patterns,alterations in leaf dimensions,leaf count,etc..Moreover,biochemical adaptations have been identified as pivotal in bolstering the plant resilience to the stress associated with higher elevation.Enzymes like superoxide dismutase(SOD)and peroxidase(POD)exhibited significant responsiveness to elevational variations,contributing to the plant's ability to confront the challenges posed by high-elevational conditions.In terms of anatomy,the plant manifested alterations in its leaf and vascular tissues along the elevational gradient.These modifications involve an increased density of stomata and a greater count of vascular bundles,optimizing gas exchange and adaptation to water stress in frequently encountered harsh environmental conditions at higher elevations.Understanding the adaptive mechanisms employed by A.stracheyi provides valuable insights,especially in forecasting how A.stracheyi might respond to global climate change,particularly in regions affected by habitat fragmentation.展开更多
Satellites in LEO (Low Earth Orbits) are closest to the Earth’s surface, having the smallest coverage area compared to other orbits, depending on altitude and elevation angle, and providing relatively too short visib...Satellites in LEO (Low Earth Orbits) are closest to the Earth’s surface, having the smallest coverage area compared to other orbits, depending on altitude and elevation angle, and providing relatively too short visibility and communication duration, in range of (2 - 15) minutes. Communication duration represents the key performance indicator for LEO satellite communication systems. For longer communication sessions, more satellites must be involved, and the signals must be handed over from one satellite to the next to provide uninterrupted real-time services to the appropriate user or ground station. This leads to the concept and structure of the satellites organized in the constellation. Communication window (visibility window) depends on the designed horizon plane width determined by licensed elevation angle. For the appropriate calculations, a satellite from the Starlink constellation at altitude of 550 km is considered, observed under licensed designed elevations of 40˚ and 25˚. Calculations under two designed elevation levels confirmed the wider horizon and consequently longer communication under the lower elevation.展开更多
The integration of Unmanned Aerial Vehicles(UAVs)and Uncrewed Surface Vehicles(USVs)has revolutionized topographic and bathymetricmapping,significantly enhancing the accuracy and efficiency of geospatial data acquisit...The integration of Unmanned Aerial Vehicles(UAVs)and Uncrewed Surface Vehicles(USVs)has revolutionized topographic and bathymetricmapping,significantly enhancing the accuracy and efficiency of geospatial data acquisition processes.This innovative approach synergistically combines terrestrial data collected by UAVs with underwater data obtained through USVs,culminating in the creation of unified high-resolution Digital Elevation Models(DEMs)of the river basin region represents a vital step toward understanding the dynamic interactions between land and water bodies.Hence,the seamless Topo-Bathymetric Elevation Model offers a detailed perspective of the river system,supporting informed decision-making in addressing sediment transport,erosion,and river morphology.This manuscript provides a comprehensive review examines the advanced methodologies for creating seamlessmultisource Topo-Bathymetry ElevationModels(TBEMs)in river basin contexts,emphasising critical factors such as cost-effectiveness,operational efficiency,and data precision.In particular,UAVs deliver high-resolution(1-3 cm)topographic mapping with 5-10 km operational ranges,while USVs provide complementary bathymetric data(1 m resolution)across 3-5 km.This synergy enables seamless land-water surveys,achieving superior precision(±8 cmterrestrial,±3 cmunderwater)and efficiency over traditional methods.By analysing the benefits and limitations inherent in these technologies,this review elucidates the potential of UAV-USV synergy to improve the accuracy and reliability of geospatial data,thereby supporting well-versed decision-making processes in environmental management and conservation efforts.Furthermore,the findings underscore the broader implications of this integrated approach for riverine and coastal studies,advocating for its wider adoption in various applications,including habitat monitoring,flood risk assessment,and sustainable resource management.The synthesis of terrestrial and aquatic data through UAV-USV collaboration not only advances the field of geospatial science but also fosters a deeper understanding of the interdependencies between land and water systems,ultimately contributing to more effective environmental stewardship.展开更多
Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier...Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier stability.The Ross Ice Shelf(RIS),the largest body of floating ice on Earth,plays an essential role in any changes in the mass balance of the Antarctic Ice Sheet.The long-term elevation change trend of RIS has been calculated with multiple satellite altimetry in previous studies.However,the seasonal variations were less revealed.Based on crossover analysis and indirect observation adjustments,this study proposed a new method for constructing seasonal records for surface elevation changes in the RIS using ICESat laser altimetry data from 2003 to 2009.The results showed that surface elevation changes exhibited seasonal variations with fluctuations over 20 cm,and the seasonal change characteristics were closely related to the temperature.Interannual variations in RIS surface elevation decreased from 2003 to2009 at a rate of 2 cm/yr.From March 2003 to April 2007,the surface elevation decreased at 3.7 cm/yr;however,after April 2007,the surface elevation increased at 5.5 cm/yr.The more recent stages of surface elevation growth have been influenced by reductions in the summer basal melt,which is related to the decreases in ocean heat content.展开更多
Climate warming causes mountainous species to shift their distributions towards higher elevations.How elevation influences growth-climate relationship in mountain regions has been intensively investigated.However,how ...Climate warming causes mountainous species to shift their distributions towards higher elevations.How elevation influences growth-climate relationship in mountain regions has been intensively investigated.However,how microtopography shapes tree growth and its drought resistance along the elevation gradient remains poorly understood.We used a network of Larix principis-rupprechtii tree-ring data comprising 1,918 trees from different age classes and mountain slopes,along an elevation gradient ranging from 970 to 1,869 m,to investigate how slope gradients mediate the growth and drought resilience of larch trees along an elevation gradient in North China.Growing season drought and temperature were the major limiting climatic factors for larch trees across the study region.Larch trees younger than 40 years exhibited a stronger positive correlation between basal area increment(BAI)and elevation on steep slopes(10°-35°)than on flat(0°-5°)or gentle(5°-10°)slopes.At low-elevation steep slopes,the growth of larch trees younger than 40 years showed a stronger correlation with the Palmer drought severity index(PDSI).Both resistance and resilience were found to increase along the elevation gradient on steep slopes for young larch trees but not for old larch trees.No significant differences were observed in the drought recovery ability of larch trees across all age groups at increasing elevation.Our results highlight that drought events may particularly affect the growth of young larch trees on low-elevation steep slopes,with potential repercussions on mortality rates.展开更多
Although the Vietnamese Mekong Delta(VMD) is recognised as one of the world's most vulnerable deltas, scholars have yet to provide an integrated diagnosis linking locally driven pressures to actionable pathways fo...Although the Vietnamese Mekong Delta(VMD) is recognised as one of the world's most vulnerable deltas, scholars have yet to provide an integrated diagnosis linking locally driven pressures to actionable pathways for halting its rapid elevation loss. The VMD-39,000 km^(2) that feeds 18 million people-is sinking because four pressures act in concert: upstream dams have already cut sediment delivery by 70 %–83 %(projected 96 % if all planned projects proceed), mean sea level is rising 1.5–2 cm/yr, river-bed sand mining now removes about 3 Mm^(3)/yr and deepens channels by up to 15 cm/yr, and groundwater withdrawals of approximately 2.5 Mm^(3)/day have accelerated landsurface subsidence from smaller than 3 cm/yr in 2006–2010 to peaks of 5–6 cm/yr today. Scenario modelling shows that halving pumping would stabilize aquifer heads and cut subsidence by about 50 % within a decade,while provincial sand-quota cuts of 30 %–50 % would slow bed incision and ease salinity intrusion, reducing the irrigation deficits that drive further pumping. While the large-scale causes of subsidence(dams, sea level rise, sand mining, groundwater extraction) are well recognized, actionable, local-level management solutions to immediately slow subsidence and salinity intrusion-independent of slow international negotiations-have been underexplored and under-implemented. Because dam and climate remedies rely on slow transboundary negotiations, we target the more practical local pressures-sand mining and groundwater extraction-by first tightening sand-mining licenses, enforcing tiered groundwater tariffs, and scaling up rain-and surface-water alternatives, buying time for longer-term basin and climate agreements. These locally actionable measures can significantly reduce subsidence and provide a scalable model for sustaining deltas around the world.展开更多
Land subsidence significantly impacts the accuracy of the National Elevation Datum in China.In order to solve this issue,a dynamic and economical way was proposed to update the National Elevation Datum with the assist...Land subsidence significantly impacts the accuracy of the National Elevation Datum in China.In order to solve this issue,a dynamic and economical way was proposed to update the National Elevation Datum with the assistance of InSAR in the North China Plain,which served as the research area.Moreover,the GNSS result was used to correct the InSAR result for the vertical deformation field,which has a relatively unified deformation reference.By integrating the vertical deformation field with the national elevation control point,an analysis and evaluation of changes in the National Elevation Datum were conducted.In addition,a regional remeasurement scheme was formulated to achieve dynamic updates and mainte-nance of the National Elevation Datum on a regional scale.Through data acquisition and processing,we successfully improved reliability within the main subsidence areas for future use.As a result,updating the elevation values utilize a regional update method,and a dynamic and economical technical process to update the National Elevation Datum is shown in the study.展开更多
BACKGROUND Primary percutaneous coronary intervention(PCI)is the preferred treatment for ST-segment elevation myocardial infarction(STEMI).However,in patients with high thrombus burden,immediate stenting during PCI ca...BACKGROUND Primary percutaneous coronary intervention(PCI)is the preferred treatment for ST-segment elevation myocardial infarction(STEMI).However,in patients with high thrombus burden,immediate stenting during PCI can lead to poor outcomes due to the risk of thrombus migration and subsequent microvascular occlusion,resulting in no-reflow phenomena.Deferred stenting offers a potential advantage by allowing for the reduction of thrombus load,which may help to minimize the incidence of slow-flow and no-reflow complications.This study explores the effectiveness of a deferred stenting strategy in improving outcomes for STEMI patients.AIM To evaluate the effectiveness and safety of deferred PCI in a real-world setting in acute STEMI patients.METHODS RESULTS Anterior wall myocardial infarction was the predominant type of STEMI in 62%of the selected 55 patients(mean age:54 years;70%males),and diabetes mellitus was the most common risk factor(18.2%),followed by hypertension(16.2%).On the second angiogram of these patients measures of thrombus grade,thrombolysis in myocardial infarction flow grade,myocardial blush grade,and severity of stenosis of culprit lesion were consid-erably improved compared to the first angiogram,and the average culprit artery diameter had increased by 7.8%.Most patients(60%)had an uneventful hospital stay during the second angiogram and an uneventful intrapro-cedural course(85.19%),with slow-flow/no-reflow occurring only in 7.4%of the patients;these patients recovered after taking vasodilator drugs.In 29.3%of patients,the culprit artery was recanalized,preventing unnecessary stent deployment.CONCLUSION Deferred PCI strategy is safe and reduces the thrombus burden,improves thrombolysis in myocardial infarction(TIMI)flow,improves myocardial blush grade,and prevents unwarranted stent deployment.展开更多
Background Although the age,creatinine,and ejection fraction(ACEF)score effectively predicts risk in general populations with ST segment elevation myocardial infarction(STEMI),its performance specifically in elderly p...Background Although the age,creatinine,and ejection fraction(ACEF)score effectively predicts risk in general populations with ST segment elevation myocardial infarction(STEMI),its performance specifically in elderly patients-who are often underrepresented in validation studies and present with unique pathophysiology-is not well established.This study was designed to directly evaluate and compare the predictive value of the ACEF score for short-term mortality in elderly versus non-elderly STEMI patients,addressing a critical gap in its clinical application.Methods We enrolled 934 consecutive STEMI patients undergoing percutaneous coronary intervention,categorized into a non elderly group(<65 years,n=534)and an elderly group(≥65 years,n=400).The ACEF score was calculated as age/left ventricular ejection fraction+1(if serum creatinine>2 mg/dL).Its predictive ability for in hospital and one year mortality was assessed.Results Overall,in hospital and one year mortality rates were 4.4%and 8.2%,respectively.Elderly patients had significantly worse in hospital outcomes,including higher all cause mortality(6.5%vs.2.8%,P=0.006)and major adverse cardiovascular events(16.0%vs.9.2%,P=0.002).The predictive performance of the ACEF score for in hospital mortality was lower in the elderly group than in the non elderly group(area under the curve:0.753 vs.0.828,P=0.047).The optimal cut off value for ACEF was 1.65 in both groups.In multivariate analysis,an ACEF score>1.65 independently predicted in hospital mortality[adjusted odds ratio(OR):11.58,P=0.001]and one year mortality[adjusted hazard ratio(HR):7.12,P<0.001]in non elderly patients.Similar associations were observed in elderly patients(in hospital mortality:adjusted OR:3.26,P=0.027;one year mortality:adjusted HR:2.79,P=0.003).Conclusions Despite a relatively lower discriminatory ability for short-term mortality in elderly STEMI patients,the ACEF score still demonstrated significant predictive value and might serve as a practical,initial tool for identifying high-risk individuals in clinical settings.展开更多
Elevation change monitoring of the Antarctic ice sheet has been a key issue in global change research.Satellite altimetry has been proven to be effective in detecting ice sheet variations. With the development of ICES...Elevation change monitoring of the Antarctic ice sheet has been a key issue in global change research.Satellite altimetry has been proven to be effective in detecting ice sheet variations. With the development of ICESat-2, many elevation observations can be used to derive elevation changes. However, the large amount of multitemporal data may include anomalous data points, increasing the uncertainty of the results. In this work, we improved the traditional repeat track method by introducing the Institute of Geodesy and Geophysics Ⅲ(IGGⅢ) method to obtain high-accuracy estimates of elevation change. The improved method was applied to analyze elevation changes along the transect from Zhongshan Station to Dome A in East Antarctica via ICESat-2 satellite altimetry data. The results show that the improved and traditional methods yield consistent numerical and spatial elevation change distributions. The elevation change calculated via the traditional method is 0.033 ± 0.131 m/yr, whereas the elevation change estimated via the IGGⅢ robust estimation method is 0.033 ± 0.109 m/yr from March 2019 to December 2021.In terms of spatial distribution, elevation changes in inland areas remain close to equilibrium, whereas regions with steeper ice sheet margins exhibit positive accumulation trends in elevation changes. The improved method reduces the standard error of the adjustment function from 0.975 to 0.691 m/yr. The improvement is particularly remarkable in the area between 72°S and 77°S. The results demonstrate that the IGGⅢ method effectively reduces errors caused by the inclusion of anomalous data and maintains the high data utilization rate of repeat-orbit methods.展开更多
Extreme weather events pose an ever-greater threat to people,infrastructure,and nature.Forest ecosystems are highly sensitive to extreme cold events that can disrupt ecosystem functions,especially in montane regions.I...Extreme weather events pose an ever-greater threat to people,infrastructure,and nature.Forest ecosystems are highly sensitive to extreme cold events that can disrupt ecosystem functions,especially in montane regions.Ice storms can be particularly destructive,with rapid ice accretion causing tree branches to break,even snapping or uprooting entire trees.In March 2022,the Shennongjia forest in central China experienced severe ice storm conditions that severely damaged over 230,300ha.We utilized this opportunity to assess the vulnerability of different tree types(coniferous,deciduous,and evergreen broad-leaved)and stand compositions to damage resulting from ice glaze along an elevation gradient from 1,200 to 2,400m a.s.l.Among the 7,144 trees surveyed,10.1%suffered some extent of damage,which was most prolific in the middle elevation zone.While 96.8%of all damage occurred to deciduous broadleaved trees that dominated the forest community,the most severe damage(uprooting and lower trunk breakage)occurred to coniferous trees.The extent and severity of tree damage were moderated by forest composition,with secondary effects of forest structure and slope.Abiotic factors predominantly affected coniferous trees.We emphasize that more research and monitoring are needed to better understand the full impact of extreme weather events on forests,especially as the frequency and intensity of these events increases due to climate change.展开更多
基金Under the auspices of the National Natural Science Foundation of China(No.42430511,U20A2083)the National Key Research and Development Program of China(No.2022YFF1300900)the Science and Technology Development Program of Jilin Province(No.20210509037RQ,20230101348JC)。
文摘Elevation patterns and assembly processes of soil microbial community structures are essential for understanding biogeo-chemical processes in mountain systems.Differences in soil properties caused by elevation gradients can regulate the spatial distribu-tion and network complexity of the community structure.To explore the variations in soil microbial community structures and their as-sembly mechanisms across different elevations of the Changbai Mountains,as well as their responses to environmental factors,we col-lected microbial samples along an elevational gradient(seven elevations containing four vegetation zones)on the western slope of the Changbai Mountains using the method of metagenomic sequencing.The results showed a significant difference(P<0.05)for the Chao1 index across different elevations,but no significant difference was observed for the Shannon and Simpson indices.With increasing elev-ation,the number of nodes and links in the microbial network gradually decreased.Acidobacteria were highly connected to many nodes.The microbial communities indicated a significant distance-decay relationship(P<0.001)and were affected more by stochastic pro-cesses along the elevation gradient.The results of the Structural Equation Model(SEM)showed that elevation had direct significant ef-fect on carbon(C,P<0.01),nitrogen(N,P<0.01),and phosphorus(P,P<0.05)and weak negative effect on their ecological stoi-chiometry.Elevation was one of the major variables contributing to microbial network topology.The contribution of C and N to micro-bial network complexity was higher than that of P.Our study provides valuable insights into the responses of soil microbial communit-ies to elevation variations.
基金National Key Research and Development Program of China (2022YFC3004004)National Natural Science Foundation of China (42075155,12241104)National Natural Science Foundation of China Joint Fund (U2342213)。
文摘The infrared channels of the FY-4B advanced geosynchronous radiation imagers(AGRI) play a crucial role in temperature and humidity analyses for mesoscale numerical weather prediction, particularly in enhancing the initial field quality and the forecasting accuracy of the model. This study assimilated FY-4B AGRI data into the CMA-MESO model and analyzed the bias characteristics and correction methods. Analysis of the AGRI data revealed a clear diurnal variation in the bias, which was positively correlated with the solar elevation angle. However, the diurnal variation in the bias lagged behind the solar elevation angle, likely owing to temperature changes and delayed instrument responses resulting from solar radiation. To address this issue, we propose a correction method that utilizes the solar elevation angle after an optimal time shift. Using the time-shifted solar elevation angle as a predictor effectively reduces the diurnal variation in bias and significantly improves the correction effect. This approach provides theoretical support for the assimilation of FY-4B AGRI data into mesoscale numerical weather predictions, thereby enhancing the reliability of the assimilation results.
基金supported by grants from the National Natural Science Foundation of China(Grant No.32360333)the Guizhou Provincial Science and Technology Projects(Grant Nos.ZK[2022]540 and[2023]099)+1 种基金the Survey of Amphibian and Reptile Resources in Leigongshan National Nature Reserve and Literature Publishing Services(P5226002023000019)the Guizhou Provincial Science and Technology Innovation Talent Team Construction Project 2024[Qian Ke He Talent CXTD(2025)053].
文摘Dear Editor,Mountain systems have long been refuges for many species,often viewed as"islands"that promote speciation due to geographic isolation(Rahbek et al.,2019).Their high environmental heterogeneity fosters centers of endemism,and they harbor over 85%of global species diversity(Zhao et al.,2022).Consequently,mountains are key systems for exploring biodiversity patterns along elevational gradients,where species richness often follows four recognized models:monotonic decrease,unimodal pattern(forward and backward peak patterns),and low plateau followed by a decrease along the elevational gradient(McCain et al.,2010).
基金supported by the National Key Research and Development Program of China (2024YFE0214200)the National Natural Science Foundation of China (42201072)。
文摘Mountain ecosystems offer natural gradients for exploring biodiversity patterns;however,the elevational patterns of plant species and phylogenetic diversity in the eastern Pamir Plateau remain poorly understood.As a biogeographical junction of the Central Asian mountain ranges,the eastern Pamir Plateau in China is geographically connected to the main part of the Pamir Plateau in Tajikistan,resulting in significant climatic and topographical heterogeneity and unique regional vegetation communities.In this study,we established 5 elevational transects and 91 plots (1500–4870 m) in the eastern Pamir Plateau to investigate the patterns and environmental drivers of plant diversity at both regional and local spatial scales.We examined diversity patterns and community composition using regression models and community structure analysis and quantified the relative importance of environmental factors using a random forest model.The results showed a distinct differentiation along elevation gradients,with overall plant diversity,herbaceous plant diversity,and phylogenetic diversity index increasing with elevation,whereas woody plant diversity declined.The phylogenetic structure indices (including net relatedness index and nearest taxon index) exhibited heterogeneous elevational responses,indicating that community assembly was jointly driven by environmental filtering and niche differentiation.Soil nutrients,water availability,and temperature were the primary environmental drivers,with soil factors predominantly influencing herbaceous plant diversity,while climatic variables dominated woody plant diversity.These findings demonstrate that plant diversity along elevational gradients of the eastern Pamir Plateau exhibits the characteristic patterns of a unique arid mountain ecosystem,where enhanced soil fertility and moderate moisture at higher elevations partly offset energy limitations,thereby maintaining plant diversity through functional convergence of closely related lineages.This pattern of biodiversity maintenance contrasts with the divergence-driven community assembly processes commonly observed in humid mountain systems.Overall,this study contributes to a better understanding of biodiversity maintenance in the eastern Pamir Plateau.Given its geographical continuity with the Pamir Plateau in Tajikistan,our findings can provide a basis for alpine conservation efforts across arid Central Asia.
基金supported by the Guizhou Provincial Science and Technology Projects(Grant Nos.ZK[2022]540 and[2023]099)the Survey of Amphibian and Reptile Resources in Leigongshan Nature Reserve and Literature Publishing Services(P5226002023000019).
文摘Dear Editor,Understanding patterns of species diversity is a primary research focus in macroecology,with its distribution patterns having been described and theoretically validated on a global scale(Peters et al.,2016;Sonne et al.,2025).Numerous studies have found that species richness of different taxa tends to decrease with increasing elevation and is modulated by latitudinal gradients(Peters et al.,2016;Dolson et al.,2024).This principle provides a crucial scientific basis for regional conservation planning.However,it still exhibits significant variations across different mountain ranges and taxa.
基金Under the auspices of National Social Sciences Foundation of China(No.21BJY114)。
文摘Forests exert significant biogeophysical cooling effects(CE)through processes such as increased evapotranspiration,reduced albedo,and enhanced surface roughness.However,little is known about the extent to which elevation-induced temperature differences bias the observed CE and how this bias interacts with the underlying biogeophysical mechanisms.In this study,we integrated multisensor remote sensing products and Shuttle Radar Topography Mission(SRTM)elevation data on the Google Earth Engine(GEE)platform,and applied a spatial-temporal window regression approach to quantify and correct the sensitivity of land surface temperature(LST)to elevation for forest pixels across China from 2001 to 2022.First,we found that forest LST exhibited a significant negative relationship with elevation,leading to systematic CE overestimation by 0.61 K during the day and 0.60 K at night compared with altitudecorrected CE values.Second,after correction,the CE showed clear spatial heterogeneity,with stronger daytime cooling in tropical(-0.54 K)and temperate forests(-0.24 K),and warming in cold(+0.11 K)and arid regions(+0.53 K),while most regions experienced nighttime warming.Among forest types,evergreen needleleaf forests(ENF)exhibited the strongest daytime cooling(-0.36 K),whereas deciduous broadleaf(DBF)and open shrublands(OS)tended to warm.Third,mechanism analysis revealed that elevation correction strengthened the correlations of CE with leaf area index(LAI)and evapotranspiration,while maintaining a significant negative correlation with albedo,indicating that both radiative and non-radiative processes jointly shape the unbiased CE.These findings provide a more accurate quantification of forest CE by eliminating elevation-induced bias,which providing a more accurate assessment of the climate mitigation potential of forests,which is crucial for developing more effective forest management and ecological restoration strategies.
基金supported by the National Natural Science Foundation of China(grant number 31901109)Guangdong Basic and Applied Basic Research Foundation(grant number 2021A1515110744).
文摘Understanding how and why assemblage dissimilarity changes along spatial gradient is a great challenge in ecology,because answers to these questions depend on the analytical types,dimensions,and components of beta diversity we concerned.To obtain a comprehensive understanding of assemblage dissimilarity and its implications for biodiversity conservation in the Himalayas,we explored the elevational patterns and determinants of beta diversity and its turnover and nestedness components of pairwise and multiple types and taxonomic and phylogenetic dimensions simultaneously.Patterns of beta diversity and their components of different types and dimensions were calculated based on 96 sampling quadrats along an 1800-5400 m elevational gradient.We examined whether and how these patterns differed from random expectations using null models.Furthermore,we used random forest methods to quantify the role of environmental variables representing climate,topography,and human disturbance in determining these patterns.We found that beta diversity and its turnover component,regardless of its types and dimensions,shown a hump-shaped elevational patterns.Both pairwise and multiple phylogenetic beta diversity were remarkably lower than their taxonomic counterpart.These patterns were significantly less than random expectation and were mostly associated with climate variables.In summary,our results suggested that assemblage dissimilarity of seed plants was mostly originate from the replacement of closely related species determined by climate-driven environmental filtering.Accordingly,conservation efforts should better cover elevations with different climate types to maximalize biodiversity conservation,rather than only focus on elevations with highest species richness.Our study demonstrated that comparisons of beta diversity of different types,dimensions,and components could be conductive to consensus on the origin and mechanism of assemblage dissimilarity.
文摘BACKGROUND The incidence of acute myocardial infarction(AMI)is rising,with cardiac rupture accounting for approximately 2%of deaths in patients with acute ST-segment elevation myocardial infarction(STEMI).Ventricular free wall rupture(FWR)occurs in approximately 2%of AMI patients and is notably rare in patients with non-STEMI.Types of cardiac rupture include left ventricular FWR,ventricular septal rupture,and papillary muscle rupture.The FWR usually leads to acute cardiac tamponade or electromechanical dissociation,where standard resuscitation efforts may not be effective.Ventricular septal rupture and papillary muscle rupture often result in refractory heart failure,with mortality rates over 50%,even with surgical or percutaneous repair options.CASE SUMMARY We present a rare case of an acute non-STEMI patient who suffered sudden FWR causing cardiac tamponade and loss of consciousness immediate before undergoing coronary angiography.Prompt resuscitation and emergency open-heart repair along with coronary artery bypass grafting resulted in successful patient recovery.CONCLUSION This case emphasizes the risks of AMI complications,shares a successful treatment scenario,and discusses measures to prevent such complications.
基金supported by Uttarakhand Council for Biotechnology(grant number UCB/R&D PROJECT/2022/20 dated 06.05.2022).
文摘Allium stracheyi(Baker)is widely utilized as a culinary herb and is typically encountered in the higher elevations of the Himalayas.Consequently,it is of great significance to compare the ecological adaptability of this indigenous species to alternative habitats and its introduction into new environments.This research aims to investigate and gain a comprehensive understanding of A.stracheyi,also known as faran,in Uttarakhand region.We aim to examine how this plant adapts morphologically,physiologically,biochemically,and anatomically to varying elevations,specifically at 550,2200,2460,and 3400 m above mean sea level(m AMSL).This plant demonstrated remarkable morphophysiological adjustments across various aspects of its development,encompassing modified growth patterns,alterations in leaf dimensions,leaf count,etc..Moreover,biochemical adaptations have been identified as pivotal in bolstering the plant resilience to the stress associated with higher elevation.Enzymes like superoxide dismutase(SOD)and peroxidase(POD)exhibited significant responsiveness to elevational variations,contributing to the plant's ability to confront the challenges posed by high-elevational conditions.In terms of anatomy,the plant manifested alterations in its leaf and vascular tissues along the elevational gradient.These modifications involve an increased density of stomata and a greater count of vascular bundles,optimizing gas exchange and adaptation to water stress in frequently encountered harsh environmental conditions at higher elevations.Understanding the adaptive mechanisms employed by A.stracheyi provides valuable insights,especially in forecasting how A.stracheyi might respond to global climate change,particularly in regions affected by habitat fragmentation.
文摘Satellites in LEO (Low Earth Orbits) are closest to the Earth’s surface, having the smallest coverage area compared to other orbits, depending on altitude and elevation angle, and providing relatively too short visibility and communication duration, in range of (2 - 15) minutes. Communication duration represents the key performance indicator for LEO satellite communication systems. For longer communication sessions, more satellites must be involved, and the signals must be handed over from one satellite to the next to provide uninterrupted real-time services to the appropriate user or ground station. This leads to the concept and structure of the satellites organized in the constellation. Communication window (visibility window) depends on the designed horizon plane width determined by licensed elevation angle. For the appropriate calculations, a satellite from the Starlink constellation at altitude of 550 km is considered, observed under licensed designed elevations of 40˚ and 25˚. Calculations under two designed elevation levels confirmed the wider horizon and consequently longer communication under the lower elevation.
基金financed by Universiti Teknologi Malaysia Encouragement Research Grant(Vot Q.J130000.3852.42J12)to provide incentives and financial support for UTM academic staff to lead research projects that contribute to the university’s research Key Performance Indicators(KPIs)and foster the development of high-quality,competitive research proposals.
文摘The integration of Unmanned Aerial Vehicles(UAVs)and Uncrewed Surface Vehicles(USVs)has revolutionized topographic and bathymetricmapping,significantly enhancing the accuracy and efficiency of geospatial data acquisition processes.This innovative approach synergistically combines terrestrial data collected by UAVs with underwater data obtained through USVs,culminating in the creation of unified high-resolution Digital Elevation Models(DEMs)of the river basin region represents a vital step toward understanding the dynamic interactions between land and water bodies.Hence,the seamless Topo-Bathymetric Elevation Model offers a detailed perspective of the river system,supporting informed decision-making in addressing sediment transport,erosion,and river morphology.This manuscript provides a comprehensive review examines the advanced methodologies for creating seamlessmultisource Topo-Bathymetry ElevationModels(TBEMs)in river basin contexts,emphasising critical factors such as cost-effectiveness,operational efficiency,and data precision.In particular,UAVs deliver high-resolution(1-3 cm)topographic mapping with 5-10 km operational ranges,while USVs provide complementary bathymetric data(1 m resolution)across 3-5 km.This synergy enables seamless land-water surveys,achieving superior precision(±8 cmterrestrial,±3 cmunderwater)and efficiency over traditional methods.By analysing the benefits and limitations inherent in these technologies,this review elucidates the potential of UAV-USV synergy to improve the accuracy and reliability of geospatial data,thereby supporting well-versed decision-making processes in environmental management and conservation efforts.Furthermore,the findings underscore the broader implications of this integrated approach for riverine and coastal studies,advocating for its wider adoption in various applications,including habitat monitoring,flood risk assessment,and sustainable resource management.The synthesis of terrestrial and aquatic data through UAV-USV collaboration not only advances the field of geospatial science but also fosters a deeper understanding of the interdependencies between land and water systems,ultimately contributing to more effective environmental stewardship.
基金supported by the National Key Research and Development Program of China under grant numbers 2023YFC2809103 and 2024YFC2813505the National Natural Science Foundation of China under the grant number 41706216+2 种基金the Fundamental Research Funds for the Central Universities under grant numbers 2042022kf1204,2042022kf1069,2042023gf0012,2042022dx0001the Hubei Provincial Natural Science Foundation of China under grant number 2022CFB081the State Key Laboratory of Geodesy and Earth's Dynamics,Innovation Academy for Precision Measurement Science and Technology under grant number SKLGED2023-2-6。
文摘Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier stability.The Ross Ice Shelf(RIS),the largest body of floating ice on Earth,plays an essential role in any changes in the mass balance of the Antarctic Ice Sheet.The long-term elevation change trend of RIS has been calculated with multiple satellite altimetry in previous studies.However,the seasonal variations were less revealed.Based on crossover analysis and indirect observation adjustments,this study proposed a new method for constructing seasonal records for surface elevation changes in the RIS using ICESat laser altimetry data from 2003 to 2009.The results showed that surface elevation changes exhibited seasonal variations with fluctuations over 20 cm,and the seasonal change characteristics were closely related to the temperature.Interannual variations in RIS surface elevation decreased from 2003 to2009 at a rate of 2 cm/yr.From March 2003 to April 2007,the surface elevation decreased at 3.7 cm/yr;however,after April 2007,the surface elevation increased at 5.5 cm/yr.The more recent stages of surface elevation growth have been influenced by reductions in the summer basal melt,which is related to the decreases in ocean heat content.
基金funded by the National Natural Science Foundation of China(No.U24A20353)the S&T Program of Hebei(Nos.226Z6801G,C2021204002,and 20210365)+1 种基金the Talent Introduction Program in Hebei Agricultural University(No.YJ201918)supported by the SERI-funded ERC Starting Grant,project MB23.00011.
文摘Climate warming causes mountainous species to shift their distributions towards higher elevations.How elevation influences growth-climate relationship in mountain regions has been intensively investigated.However,how microtopography shapes tree growth and its drought resistance along the elevation gradient remains poorly understood.We used a network of Larix principis-rupprechtii tree-ring data comprising 1,918 trees from different age classes and mountain slopes,along an elevation gradient ranging from 970 to 1,869 m,to investigate how slope gradients mediate the growth and drought resilience of larch trees along an elevation gradient in North China.Growing season drought and temperature were the major limiting climatic factors for larch trees across the study region.Larch trees younger than 40 years exhibited a stronger positive correlation between basal area increment(BAI)and elevation on steep slopes(10°-35°)than on flat(0°-5°)or gentle(5°-10°)slopes.At low-elevation steep slopes,the growth of larch trees younger than 40 years showed a stronger correlation with the Palmer drought severity index(PDSI).Both resistance and resilience were found to increase along the elevation gradient on steep slopes for young larch trees but not for old larch trees.No significant differences were observed in the drought recovery ability of larch trees across all age groups at increasing elevation.Our results highlight that drought events may particularly affect the growth of young larch trees on low-elevation steep slopes,with potential repercussions on mortality rates.
基金supported by various grants from the Ministry of Education,Singapore,under its Academic Research#Tier 1[RG 142/22],#Tier 2[MOE-T2EP50222-0007],#Tier 3 Climate Transformation Programme[MOET32022-0006],NIE AcRF-RI 10/22 EP,NIE AcRF-RI 9/24 EPthe Earth Observatory of Singapore(EOS)via its funding from the National Research Foundation Singapore and the Singapore Ministry of Education under the Research Centres of Excellence initiative+1 种基金comprises EOS Contribution number 660supported by the Netherlands Science Foundation(NWO)Drowning Deltas project(NWO-Veni-TTW-2022 No 20231).
文摘Although the Vietnamese Mekong Delta(VMD) is recognised as one of the world's most vulnerable deltas, scholars have yet to provide an integrated diagnosis linking locally driven pressures to actionable pathways for halting its rapid elevation loss. The VMD-39,000 km^(2) that feeds 18 million people-is sinking because four pressures act in concert: upstream dams have already cut sediment delivery by 70 %–83 %(projected 96 % if all planned projects proceed), mean sea level is rising 1.5–2 cm/yr, river-bed sand mining now removes about 3 Mm^(3)/yr and deepens channels by up to 15 cm/yr, and groundwater withdrawals of approximately 2.5 Mm^(3)/day have accelerated landsurface subsidence from smaller than 3 cm/yr in 2006–2010 to peaks of 5–6 cm/yr today. Scenario modelling shows that halving pumping would stabilize aquifer heads and cut subsidence by about 50 % within a decade,while provincial sand-quota cuts of 30 %–50 % would slow bed incision and ease salinity intrusion, reducing the irrigation deficits that drive further pumping. While the large-scale causes of subsidence(dams, sea level rise, sand mining, groundwater extraction) are well recognized, actionable, local-level management solutions to immediately slow subsidence and salinity intrusion-independent of slow international negotiations-have been underexplored and under-implemented. Because dam and climate remedies rely on slow transboundary negotiations, we target the more practical local pressures-sand mining and groundwater extraction-by first tightening sand-mining licenses, enforcing tiered groundwater tariffs, and scaling up rain-and surface-water alternatives, buying time for longer-term basin and climate agreements. These locally actionable measures can significantly reduce subsidence and provide a scalable model for sustaining deltas around the world.
基金supported by the Scientific and Technological Innovation Project of SHASG(SCK2022-01)National Key Research and Development Program of China(2016YFC0803109)。
文摘Land subsidence significantly impacts the accuracy of the National Elevation Datum in China.In order to solve this issue,a dynamic and economical way was proposed to update the National Elevation Datum with the assistance of InSAR in the North China Plain,which served as the research area.Moreover,the GNSS result was used to correct the InSAR result for the vertical deformation field,which has a relatively unified deformation reference.By integrating the vertical deformation field with the national elevation control point,an analysis and evaluation of changes in the National Elevation Datum were conducted.In addition,a regional remeasurement scheme was formulated to achieve dynamic updates and mainte-nance of the National Elevation Datum on a regional scale.Through data acquisition and processing,we successfully improved reliability within the main subsidence areas for future use.As a result,updating the elevation values utilize a regional update method,and a dynamic and economical technical process to update the National Elevation Datum is shown in the study.
文摘BACKGROUND Primary percutaneous coronary intervention(PCI)is the preferred treatment for ST-segment elevation myocardial infarction(STEMI).However,in patients with high thrombus burden,immediate stenting during PCI can lead to poor outcomes due to the risk of thrombus migration and subsequent microvascular occlusion,resulting in no-reflow phenomena.Deferred stenting offers a potential advantage by allowing for the reduction of thrombus load,which may help to minimize the incidence of slow-flow and no-reflow complications.This study explores the effectiveness of a deferred stenting strategy in improving outcomes for STEMI patients.AIM To evaluate the effectiveness and safety of deferred PCI in a real-world setting in acute STEMI patients.METHODS RESULTS Anterior wall myocardial infarction was the predominant type of STEMI in 62%of the selected 55 patients(mean age:54 years;70%males),and diabetes mellitus was the most common risk factor(18.2%),followed by hypertension(16.2%).On the second angiogram of these patients measures of thrombus grade,thrombolysis in myocardial infarction flow grade,myocardial blush grade,and severity of stenosis of culprit lesion were consid-erably improved compared to the first angiogram,and the average culprit artery diameter had increased by 7.8%.Most patients(60%)had an uneventful hospital stay during the second angiogram and an uneventful intrapro-cedural course(85.19%),with slow-flow/no-reflow occurring only in 7.4%of the patients;these patients recovered after taking vasodilator drugs.In 29.3%of patients,the culprit artery was recanalized,preventing unnecessary stent deployment.CONCLUSION Deferred PCI strategy is safe and reduces the thrombus burden,improves thrombolysis in myocardial infarction(TIMI)flow,improves myocardial blush grade,and prevents unwarranted stent deployment.
文摘Background Although the age,creatinine,and ejection fraction(ACEF)score effectively predicts risk in general populations with ST segment elevation myocardial infarction(STEMI),its performance specifically in elderly patients-who are often underrepresented in validation studies and present with unique pathophysiology-is not well established.This study was designed to directly evaluate and compare the predictive value of the ACEF score for short-term mortality in elderly versus non-elderly STEMI patients,addressing a critical gap in its clinical application.Methods We enrolled 934 consecutive STEMI patients undergoing percutaneous coronary intervention,categorized into a non elderly group(<65 years,n=534)and an elderly group(≥65 years,n=400).The ACEF score was calculated as age/left ventricular ejection fraction+1(if serum creatinine>2 mg/dL).Its predictive ability for in hospital and one year mortality was assessed.Results Overall,in hospital and one year mortality rates were 4.4%and 8.2%,respectively.Elderly patients had significantly worse in hospital outcomes,including higher all cause mortality(6.5%vs.2.8%,P=0.006)and major adverse cardiovascular events(16.0%vs.9.2%,P=0.002).The predictive performance of the ACEF score for in hospital mortality was lower in the elderly group than in the non elderly group(area under the curve:0.753 vs.0.828,P=0.047).The optimal cut off value for ACEF was 1.65 in both groups.In multivariate analysis,an ACEF score>1.65 independently predicted in hospital mortality[adjusted odds ratio(OR):11.58,P=0.001]and one year mortality[adjusted hazard ratio(HR):7.12,P<0.001]in non elderly patients.Similar associations were observed in elderly patients(in hospital mortality:adjusted OR:3.26,P=0.027;one year mortality:adjusted HR:2.79,P=0.003).Conclusions Despite a relatively lower discriminatory ability for short-term mortality in elderly STEMI patients,the ACEF score still demonstrated significant predictive value and might serve as a practical,initial tool for identifying high-risk individuals in clinical settings.
基金supported by the National Key Research and Development Program of China under grant number 2023YFC2809103the Fundamental Research Funds for the Central Universities under grant numbers 2042022kf1204, 2042022kf1069, 2042023gf0012, 2042022dx0001+1 种基金the Hubei Provincial Natural Science Foundation of China under grant number 2022CFB081the State Key Laboratory of Geodesy and Earth's Dynamics, Innovation Academy for Precision Measurement Science and Technology under grant number SKLGED2023-2-6
文摘Elevation change monitoring of the Antarctic ice sheet has been a key issue in global change research.Satellite altimetry has been proven to be effective in detecting ice sheet variations. With the development of ICESat-2, many elevation observations can be used to derive elevation changes. However, the large amount of multitemporal data may include anomalous data points, increasing the uncertainty of the results. In this work, we improved the traditional repeat track method by introducing the Institute of Geodesy and Geophysics Ⅲ(IGGⅢ) method to obtain high-accuracy estimates of elevation change. The improved method was applied to analyze elevation changes along the transect from Zhongshan Station to Dome A in East Antarctica via ICESat-2 satellite altimetry data. The results show that the improved and traditional methods yield consistent numerical and spatial elevation change distributions. The elevation change calculated via the traditional method is 0.033 ± 0.131 m/yr, whereas the elevation change estimated via the IGGⅢ robust estimation method is 0.033 ± 0.109 m/yr from March 2019 to December 2021.In terms of spatial distribution, elevation changes in inland areas remain close to equilibrium, whereas regions with steeper ice sheet margins exhibit positive accumulation trends in elevation changes. The improved method reduces the standard error of the adjustment function from 0.975 to 0.691 m/yr. The improvement is particularly remarkable in the area between 72°S and 77°S. The results demonstrate that the IGGⅢ method effectively reduces errors caused by the inclusion of anomalous data and maintains the high data utilization rate of repeat-orbit methods.
基金supported by the National Natural Science Foundation of China(Nos.31971541 and 32201545).
文摘Extreme weather events pose an ever-greater threat to people,infrastructure,and nature.Forest ecosystems are highly sensitive to extreme cold events that can disrupt ecosystem functions,especially in montane regions.Ice storms can be particularly destructive,with rapid ice accretion causing tree branches to break,even snapping or uprooting entire trees.In March 2022,the Shennongjia forest in central China experienced severe ice storm conditions that severely damaged over 230,300ha.We utilized this opportunity to assess the vulnerability of different tree types(coniferous,deciduous,and evergreen broad-leaved)and stand compositions to damage resulting from ice glaze along an elevation gradient from 1,200 to 2,400m a.s.l.Among the 7,144 trees surveyed,10.1%suffered some extent of damage,which was most prolific in the middle elevation zone.While 96.8%of all damage occurred to deciduous broadleaved trees that dominated the forest community,the most severe damage(uprooting and lower trunk breakage)occurred to coniferous trees.The extent and severity of tree damage were moderated by forest composition,with secondary effects of forest structure and slope.Abiotic factors predominantly affected coniferous trees.We emphasize that more research and monitoring are needed to better understand the full impact of extreme weather events on forests,especially as the frequency and intensity of these events increases due to climate change.
