Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain unc...Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain uncertain in arid mountain ecosystems,where climosequences are quite different from other ecosystems.To address this gap,this study investigated the distribution determinants of microbial communities,C cycling-related genes,and SOC fractions along an elevational gradient(1707–3548 m),with a mean annual precipitation(MAP)range of 38 to 344 mm,on the north slope of the central part of the Kunlun Mountains,China using a metagenomic approach.The results showed that elevation significantly influenced the α-diversity(Shannon index)and composition of microbial communities as well as the C cycling-related genes.The α-diversities of microbial taxa and C cycling-related genes linearly increased with the increase in MAP along the elevational gradient.The elevational patterns of the genes encoding glycoside hydrolases and glycosyl transferases(GTs)were mainly driven by soil electrical conductivity(EC),mean annual temperature(MAT),MAP,and plant diversity.Furthermore,mineral-associated organic C(MAOC),particulate organic C(POC),and their sum generally increased with elevation.However,the MAOC/POC ratio followed a unimodal pattern,suggesting greater stability of the SOC pool in the mid-elevation regions.This unimodal pattern was likely influenced by the abundances of Actinobacteria and the genes encoding GTs and carbohydrate esterases and the threshold effects of soil EC and MAT.In summary,our findings indicate that the distribution patterns of microbial communities and C cycling-related genes along the elevational gradient in an arid ecosystem are distinct from those in the regions with higher MAP,facilitating the prediction of climate change effects on SOC metabolism under more arid conditions.Soil salinity,plant diversity,precipitation,and temperature are the main regulatory factors of microbial C metabolism processes,and they potentially play a central role in mediating SOC pool stability.展开更多
Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study,...Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.展开更多
Elevation is one of many components that influence agriculture, and this in turn affects the level of both inputs and outputs of farmers. This article focuses on the productivity and technical efficiency of 100 cocoa ...Elevation is one of many components that influence agriculture, and this in turn affects the level of both inputs and outputs of farmers. This article focuses on the productivity and technical efficiency of 100 cocoa farms using cross-sectional data from areas ranging from 190 to 1021 m above sea level which were classified as low, medium, and high elevation in Davao City, considered as the chocolate capital of the Philippines. Using stochastic frontier analysis, the results showed that the cost of inputs per ha and the number of cocoa trees per ha significantly increase yield. Farms at high elevations were less technically efficient, as this entails lower temperatures and increased rainfall, and cocoa farming in those areas and conditions can be more challenging, especially with changes in farming practices, terrain, and distance to markets. Other significant variables were age of cocoa farms, married farmers, and age of the farmers. Older farms may be more developed, farmers who are married benefit from their spouses being able to readily contribute as farm labor, and lastly, older farmers' inefficiency may likely stem from nonadaptation of newer farming practices. With an average technical efficiency of 0.61, 0.63, and 0.26 in low, medium, and high elevation areas, respectively, farmers therefore have an incentive to improve farm practices and consider topographical variations found in high elevation areas. Recommendations for the improvement of technical efficiency of cocoa farms are better connectivity to markets, enhancing farm practices, and continuation and improvement of government programs on cocoa with an added emphasis on research. For farmers in high elevation areas, mitigating solutions such as sustainable agriculture practices and ecolabelling are key to improving efficiency and minimizing the potential negative impact on upland farming systems. Moreover, such adaptation measures may also contribute to sustainability of cocoa farming in high elevation areas.展开更多
Understanding climatic effects on cropland water use efficiency at different elevations is imperative for managing agricultural water and production in response to ongoing climate change in climate-sensitive areas wit...Understanding climatic effects on cropland water use efficiency at different elevations is imperative for managing agricultural water and production in response to ongoing climate change in climate-sensitive areas with complex topography, such as southwestern China. We investigated climatic effects on cropland water use efficiency in southwestern China at each 100-m elevation bin during 2001–2017. The maximum water use efficiency was 1.71 gC kg^(–1) H_2O for the 1900–1999 m elevation bin under the growing season temperature and precipitation of 14.58±0.32℃ and 965.40±136.45 mm, respectively. The water use efficiency slopes were dominated by the evapotranspiration slopes at elevations below 1999 m but were controlled by the gross primary productivity slopes at elevations above 2000 m. This difference was caused by the substantial responses of evaporation to climate change at lower elevations and the increased climatic sensitivity of gross primary productivity at higher elevations. In comparison to those at other elevations, croplands at lower elevations were more vulnerable to extreme drought because of the dominant role fluctuating evapotranspiration played in water use efficiency. The findings will improve cropland water management in the study area.展开更多
Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter＇ s security and other performance capabilitie...Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter＇ s security and other performance capabilities. In testing, however, it has been difficult to measure the elevation when the rotor reaches high speeds. To get a simple, fast and highly accurate measurement system, photo electricity technology was applied to measuring the blade running elevation. Discussed is the measurement principle of blade running elevation, tire design of the measurement system and analysis of the measurement precision.展开更多
Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradient...Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.展开更多
Objectives:Meta-analysis was performed to evaluate the effect of staged revascularization with concomitant chronic total occlusion(CTO)in the non-infarct-associated artery(non-IRA)in patients with ST-segment elevation...Objectives:Meta-analysis was performed to evaluate the effect of staged revascularization with concomitant chronic total occlusion(CTO)in the non-infarct-associated artery(non-IRA)in patients with ST-segment elevation myocardial infarction(STEMI)treated with primary percutaneous coronary intervention(p-PCI).Methods:Various electronic databases were searched for studies published from inception to June,2021.The primary endpoint was all-cause death,and the secondary endpoint was a composite of major adverse cardiac events(MACEs).Odds ratios(ORs)were pooled with 95%confidence intervals(CIs)for dichotomous data.Results:Seven studies involving 1540 participants were included in thefinal analysis.Pooled analyses revealed that patients with successful staged revascularization for CTO in non-IRA with STEMI treated with p-PCI had overall lower all-cause death compared with the occluded CTO group(OR,0.46;95%CI,0.23–0.95),cardiac death(OR,0.43;95%CI,0.20–0.91),MACEs(OR,0.47;95%CI,0.32–0.69)and heart failure(OR,0.57;95%CI,0.37–0.89)com-pared with the occluded CTO group.No significant differences were observed between groups regarding myocardial infarction and repeated revascularization.Conclusions:Successful revascularization of CTO in the non-IRA was associated with better outcomes in patients with STEMI treated with p-PCI.展开更多
We have developed a web-based processing system that can simulate positive and negative sea level changes globally by selecting the best Digital Elevation Model (DEM) for a target region from multiple DEMs. A PNG elev...We have developed a web-based processing system that can simulate positive and negative sea level changes globally by selecting the best Digital Elevation Model (DEM) for a target region from multiple DEMs. A PNG elevation tile format is used as the DEM format, which reduces the DEM data size. The PNG tile format implements client-based processing, and the DEM data are provided from different websites. In addition, the smart tile architecture is adopted, which enables on-demand simulation by adding a tile conversion process (<em>i.e.</em>, a DEM selection process) during image drawing by using JavaScript. To demonstrate the system, we have employed three DEMs,<em> i.e.</em>, the Geospatial Information Authority of Japan (GSI) map (~10-m resolution), the ASTER Global Digital Elevation Models (ASTER GDEM version 3) as global land area (~30-m resolution), and the General Bathymetric Chart of the Oceans as bathymetric data (~1000-m resolution). The ASTER Global Water Bodies Database is also used in the data selection process. The GSI provides their DEM in a PNG elevation tile format, and the other data are provided by the Geological Survey of Japan in PNG elevation tile format. We assume the current DEM sea level as 0 m, and the sea level can be changed to an arbitrary integer value (<span style="white-space:nowrap;">−</span>10,000 to 10,000 m). Combining ASTER GDEM for land and GEBCO for sea makes it possible to target DEM of the whole earth. Moreover, it was shown that if a higher resolution DEM is available, it is possible to combine the higher resolution DEM in that area. The combining the PNG elevation tile format with the smart tile architecture demonstrates the possibilities of a client-based web processing service like that of the server-based OGC Web Processing Service.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
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
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
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
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
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
Climate change in High Mountain Asia(HMA)is characterized by elevation dependence,which results in vertical zoning of vegetation distribution.However,few studies have been conducted on the distribution patterns of veg...Climate change in High Mountain Asia(HMA)is characterized by elevation dependence,which results in vertical zoning of vegetation distribution.However,few studies have been conducted on the distribution patterns of vegetation,the response of vegetation to climate change,and the key climatic control factors of vegetation along the elevation gradient in this region.In this study,based on the Normalized Difference Vegetation index(NDVI),we investigated the evolution pattern of vegetation in HMA during 2001-2020 using linear trend and Bayesian Estimator of Abrupt change,Seasonality,and Trend(BEAST)methods.Pearson correlation analysis and partial correlation analysis were used to explore the response relationship between vegetation and climatic factors along the elevation gradient.Path analysis was employed to quantitatively reveal the dominant climatic factors affecting vegetation distribution along the elevation gradient.The results showed that NDVI in HMA increased at a rate of 0.011/10a from 2001 to 2020,and the rate of increase abruptly slowed down after 2017.NDVI showed a fluctuating increase at elevation zones 1-2(<2500 m)and then decreased at elevation zones 3-9(2500-6000 m)with the increase of elevation.NDVI was most sensitive to precipitation and temperature at a 1-month lag.With the increase of elevation,the positive response relationship of NDVI with precipitation gradually weakened,while that of NDVI with temperature was the opposite.The total effect coefficient of precipitation(0.95)on vegetation was larger than that of temperature(0.87),indicating that precipitation is the dominant control factor affecting vegetation growth.Spacially,vegetation growth is jointly influenced by precipitation and temperature,but the influence of precipitation on vegetation growth is dominant at each elevation zone.The results of this study contribute to understanding how the elevation gradient effect influences the response of vegetation to climate change in alpine ecosystems.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sponsored by the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China(No.2022D01B213)the Key Scientific and Technological Research Projects in the Xinjiang Production and Construction Corps,China(No.2023AB017-02)+1 种基金the West Light Foundation for Young Scholar of Chinese Academy of Sciences(No.2021-XBQNXZ-018)the National Key Research and Development Program of China(No.2022YFF1302504)。
文摘Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain uncertain in arid mountain ecosystems,where climosequences are quite different from other ecosystems.To address this gap,this study investigated the distribution determinants of microbial communities,C cycling-related genes,and SOC fractions along an elevational gradient(1707–3548 m),with a mean annual precipitation(MAP)range of 38 to 344 mm,on the north slope of the central part of the Kunlun Mountains,China using a metagenomic approach.The results showed that elevation significantly influenced the α-diversity(Shannon index)and composition of microbial communities as well as the C cycling-related genes.The α-diversities of microbial taxa and C cycling-related genes linearly increased with the increase in MAP along the elevational gradient.The elevational patterns of the genes encoding glycoside hydrolases and glycosyl transferases(GTs)were mainly driven by soil electrical conductivity(EC),mean annual temperature(MAT),MAP,and plant diversity.Furthermore,mineral-associated organic C(MAOC),particulate organic C(POC),and their sum generally increased with elevation.However,the MAOC/POC ratio followed a unimodal pattern,suggesting greater stability of the SOC pool in the mid-elevation regions.This unimodal pattern was likely influenced by the abundances of Actinobacteria and the genes encoding GTs and carbohydrate esterases and the threshold effects of soil EC and MAT.In summary,our findings indicate that the distribution patterns of microbial communities and C cycling-related genes along the elevational gradient in an arid ecosystem are distinct from those in the regions with higher MAP,facilitating the prediction of climate change effects on SOC metabolism under more arid conditions.Soil salinity,plant diversity,precipitation,and temperature are the main regulatory factors of microbial C metabolism processes,and they potentially play a central role in mediating SOC pool stability.
基金funded by the Korea Green Promotion Agency, Korea Forest Service
文摘Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.
文摘Elevation is one of many components that influence agriculture, and this in turn affects the level of both inputs and outputs of farmers. This article focuses on the productivity and technical efficiency of 100 cocoa farms using cross-sectional data from areas ranging from 190 to 1021 m above sea level which were classified as low, medium, and high elevation in Davao City, considered as the chocolate capital of the Philippines. Using stochastic frontier analysis, the results showed that the cost of inputs per ha and the number of cocoa trees per ha significantly increase yield. Farms at high elevations were less technically efficient, as this entails lower temperatures and increased rainfall, and cocoa farming in those areas and conditions can be more challenging, especially with changes in farming practices, terrain, and distance to markets. Other significant variables were age of cocoa farms, married farmers, and age of the farmers. Older farms may be more developed, farmers who are married benefit from their spouses being able to readily contribute as farm labor, and lastly, older farmers' inefficiency may likely stem from nonadaptation of newer farming practices. With an average technical efficiency of 0.61, 0.63, and 0.26 in low, medium, and high elevation areas, respectively, farmers therefore have an incentive to improve farm practices and consider topographical variations found in high elevation areas. Recommendations for the improvement of technical efficiency of cocoa farms are better connectivity to markets, enhancing farm practices, and continuation and improvement of government programs on cocoa with an added emphasis on research. For farmers in high elevation areas, mitigating solutions such as sustainable agriculture practices and ecolabelling are key to improving efficiency and minimizing the potential negative impact on upland farming systems. Moreover, such adaptation measures may also contribute to sustainability of cocoa farming in high elevation areas.
基金National Natural Science Foundation of China,No.41501054Scientific Research Foundation of Shandong Technology and Business University,No.BS201735Key Research Program of Frontier Sciences of the Chinese Academy of Sciences,No.QYZDB-SSW-DQC005。
文摘Understanding climatic effects on cropland water use efficiency at different elevations is imperative for managing agricultural water and production in response to ongoing climate change in climate-sensitive areas with complex topography, such as southwestern China. We investigated climatic effects on cropland water use efficiency in southwestern China at each 100-m elevation bin during 2001–2017. The maximum water use efficiency was 1.71 gC kg^(–1) H_2O for the 1900–1999 m elevation bin under the growing season temperature and precipitation of 14.58±0.32℃ and 965.40±136.45 mm, respectively. The water use efficiency slopes were dominated by the evapotranspiration slopes at elevations below 1999 m but were controlled by the gross primary productivity slopes at elevations above 2000 m. This difference was caused by the substantial responses of evaporation to climate change at lower elevations and the increased climatic sensitivity of gross primary productivity at higher elevations. In comparison to those at other elevations, croplands at lower elevations were more vulnerable to extreme drought because of the dominant role fluctuating evapotranspiration played in water use efficiency. The findings will improve cropland water management in the study area.
文摘Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter＇ s security and other performance capabilities. In testing, however, it has been difficult to measure the elevation when the rotor reaches high speeds. To get a simple, fast and highly accurate measurement system, photo electricity technology was applied to measuring the blade running elevation. Discussed is the measurement principle of blade running elevation, tire design of the measurement system and analysis of the measurement precision.
基金carried out in the framework of the 1331 Project of Cultural Ecology Collaborative Innovation Center in Wutai Mountain (00000342)co-financed by Program for the Philosophy and Social Sciences Research of Higher Learning Institutions of Shanxi (2022J027)+1 种基金Applied Basic Research Project of Shanxi Province (202203021221225)Basic Research Project of Xinzhou Science and Technology Bureau (20230501)。
文摘Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.
基金supported by the Beijing Tsinghua Changgung Hospital Fund(grant No.12019C1009).
文摘Objectives:Meta-analysis was performed to evaluate the effect of staged revascularization with concomitant chronic total occlusion(CTO)in the non-infarct-associated artery(non-IRA)in patients with ST-segment elevation myocardial infarction(STEMI)treated with primary percutaneous coronary intervention(p-PCI).Methods:Various electronic databases were searched for studies published from inception to June,2021.The primary endpoint was all-cause death,and the secondary endpoint was a composite of major adverse cardiac events(MACEs).Odds ratios(ORs)were pooled with 95%confidence intervals(CIs)for dichotomous data.Results:Seven studies involving 1540 participants were included in thefinal analysis.Pooled analyses revealed that patients with successful staged revascularization for CTO in non-IRA with STEMI treated with p-PCI had overall lower all-cause death compared with the occluded CTO group(OR,0.46;95%CI,0.23–0.95),cardiac death(OR,0.43;95%CI,0.20–0.91),MACEs(OR,0.47;95%CI,0.32–0.69)and heart failure(OR,0.57;95%CI,0.37–0.89)com-pared with the occluded CTO group.No significant differences were observed between groups regarding myocardial infarction and repeated revascularization.Conclusions:Successful revascularization of CTO in the non-IRA was associated with better outcomes in patients with STEMI treated with p-PCI.
文摘We have developed a web-based processing system that can simulate positive and negative sea level changes globally by selecting the best Digital Elevation Model (DEM) for a target region from multiple DEMs. A PNG elevation tile format is used as the DEM format, which reduces the DEM data size. The PNG tile format implements client-based processing, and the DEM data are provided from different websites. In addition, the smart tile architecture is adopted, which enables on-demand simulation by adding a tile conversion process (<em>i.e.</em>, a DEM selection process) during image drawing by using JavaScript. To demonstrate the system, we have employed three DEMs,<em> i.e.</em>, the Geospatial Information Authority of Japan (GSI) map (~10-m resolution), the ASTER Global Digital Elevation Models (ASTER GDEM version 3) as global land area (~30-m resolution), and the General Bathymetric Chart of the Oceans as bathymetric data (~1000-m resolution). The ASTER Global Water Bodies Database is also used in the data selection process. The GSI provides their DEM in a PNG elevation tile format, and the other data are provided by the Geological Survey of Japan in PNG elevation tile format. We assume the current DEM sea level as 0 m, and the sea level can be changed to an arbitrary integer value (<span style="white-space:nowrap;">−</span>10,000 to 10,000 m). Combining ASTER GDEM for land and GEBCO for sea makes it possible to target DEM of the whole earth. Moreover, it was shown that if a higher resolution DEM is available, it is possible to combine the higher resolution DEM in that area. The combining the PNG elevation tile format with the smart tile architecture demonstrates the possibilities of a client-based web processing service like that of the server-based OGC Web Processing Service.
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.
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.
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 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.
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 Xinjiang Uygur Autonomous Region Major Scientific and Technological Special Project Research and Demonstration on the Development Model of Ecological Agriculture and Efficient Utilization of Soil and Water Resources in Modern Irrigation Areas(2023A02002-1).
文摘Climate change in High Mountain Asia(HMA)is characterized by elevation dependence,which results in vertical zoning of vegetation distribution.However,few studies have been conducted on the distribution patterns of vegetation,the response of vegetation to climate change,and the key climatic control factors of vegetation along the elevation gradient in this region.In this study,based on the Normalized Difference Vegetation index(NDVI),we investigated the evolution pattern of vegetation in HMA during 2001-2020 using linear trend and Bayesian Estimator of Abrupt change,Seasonality,and Trend(BEAST)methods.Pearson correlation analysis and partial correlation analysis were used to explore the response relationship between vegetation and climatic factors along the elevation gradient.Path analysis was employed to quantitatively reveal the dominant climatic factors affecting vegetation distribution along the elevation gradient.The results showed that NDVI in HMA increased at a rate of 0.011/10a from 2001 to 2020,and the rate of increase abruptly slowed down after 2017.NDVI showed a fluctuating increase at elevation zones 1-2(<2500 m)and then decreased at elevation zones 3-9(2500-6000 m)with the increase of elevation.NDVI was most sensitive to precipitation and temperature at a 1-month lag.With the increase of elevation,the positive response relationship of NDVI with precipitation gradually weakened,while that of NDVI with temperature was the opposite.The total effect coefficient of precipitation(0.95)on vegetation was larger than that of temperature(0.87),indicating that precipitation is the dominant control factor affecting vegetation growth.Spacially,vegetation growth is jointly influenced by precipitation and temperature,but the influence of precipitation on vegetation growth is dominant at each elevation zone.The results of this study contribute to understanding how the elevation gradient effect influences the response of vegetation to climate change in alpine ecosystems.
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.
