Earth is moving through a period of extreme uncertainty as global climates change,natural disasters become more frequent and severe,and governments grapple with the difficulty these issues pose for managing natural re...Earth is moving through a period of extreme uncertainty as global climates change,natural disasters become more frequent and severe,and governments grapple with the difficulty these issues pose for managing natural resources and people.Nowhere are these challenges more pressing than across the world's drylands,where a combination of hotter drier climates challenge food security,sustainable food production and often fuel unrest and political instability.It is against this backdrop that Fu and Stafford Smith,two global leaders in dryland science draw on>80 years of collective wisdom on drylands to describe how humans and natural processes intersect in an era of global change(Fu and Stafford Smith,2024).展开更多
A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and...A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and development of the NMI model and then emphasize that the NMI model represents a new tool for identifying the basic physics of how climate change influences mid-to-high latitude weather extremes.The building of the NMI model took place over three main periods.In the 1990s,a nonlinear Schr?dinger(NLS)equation model was presented to describe atmospheric blocking as a wave packet;however,it could not depict the lifetime(10-20 days)of atmospheric blocking.In the 2000s,we proposed an NMI model of atmospheric blocking in a uniform basic flow by making a scale-separation assumption and deriving an eddyforced NLS equation.This model succeeded in describing the life cycle of atmospheric blocking.In the 2020s,the NMI model was extended to include the impact of a changing climate mainly by altering the basic zonal winds and the magnitude of the meridional background potential vorticity gradient(PVy).Model results show that when PVy is smaller,blocking has a weaker dispersion and a stronger nonlinearity,so blocking can be more persistent and have a larger zonal scale and weaker eastward movement,thus favoring stronger weather extremes.However,when PVy is much smaller and below a critical threshold under much stronger winter Arctic warming of global warming,atmospheric blocking becomes locally less persistent and shows a much stronger westward movement,which acts to inhibit local cold extremes.Such a case does not happen in summer under global warming because PVy fails to fall below the critical threshold.Thus,our theory indicates that global warming can render summer-blocking anticyclones and mid-to-high latitude heatwaves more persistent,intense,and widespread.展开更多
Making plans is a good idea,but every one's schedule looks differe nt.You may have to talk about your plans before you're able to make some.It could sound like this:You ask,"Do you have plans this Friday ...Making plans is a good idea,but every one's schedule looks differe nt.You may have to talk about your plans before you're able to make some.It could sound like this:You ask,"Do you have plans this Friday night?"If the person already has plans,they may say,"I do.But I'm free on Saturday."If that day doesn't work for you,you can say,"I'm not available that day.How about Sunday after no on?"After you figure out the day and time,mark it on your calendar.展开更多
Protecting rare,endemic,and endangered species requires careful habitat evaluation to set strategic plans for mitigating biodiversity loss and prioritizing conservation goals.The endangered Asian elephant(Elephas maxi...Protecting rare,endemic,and endangered species requires careful habitat evaluation to set strategic plans for mitigating biodiversity loss and prioritizing conservation goals.The endangered Asian elephant(Elephas maximus)exemplifies the urgent need for targeted conservation efforts,given its challenging habitat conditions.This study examines the impact of climate and land use changes on the suitable habitat distribution of Asian elephants.Utilizing ten predictor variables,including climatic,topographic,and land use data,and employing six ensemble Species Distribution Models(SDMs)alongside Coupled Model Intercomparison Project Phase 6 data,the study estimates spatial changes and potential habitat expansions for Asian elephants across Tropical Asia.Occurrence data were gathered from field surveys in Bangladesh and the Global Biodiversity Information Facility database for Sri Lanka,Myanmar,Bhutan,Cambodia,India,Laos,Nepal,Thailand,and Vietnam.To evaluate habitat suitability,the analysis considered two distinct socioeconomic pathways(SSP 245 and SSP 370)across two future periods(2041–2060 and 2061–2080).Results reveal a strong correlation between isothermality and habitat suitability,with higher isothermality enhancing the habitat conditions for Asian elephants.Among the SDMs,the random forest model demonstrated the highest performance.Projected scenarios indicate significant habitat fragmentation by 2061–2080,heightening the risk of species’vulnerability.Specifically,in SSP 245,the north zone is anticipated to experience a higher rate of habitat loss(588.443 km^(2)/year),whereas,in SSP 370,the west zone is expected to face a more severe rate of habitat loss(1,798.56 km^(2)/year).The eastern zone,which includes Cambodia,Vietnam,Laos,Thailand,and southern Myanmar,is notably at risk,with an estimated habitat loss of 14.8 million hectares.Anticipated changes in climate and land cover will impact the availability of essential resources such as food,water,and shelter,potentially driving the species to relocate to different elevation belts.The outcomes of the consensus map highlighting critical habitats and future fragmentation scenarios will support effective conservation and management strategies for the species.展开更多
This study,based on the theory of shifting essence and changing Qi in Inner Canon of Huangdi,deeply explores the theoretical basis,operation method of Conception Vessel Dredging Therapy and its influence on human heal...This study,based on the theory of shifting essence and changing Qi in Inner Canon of Huangdi,deeply explores the theoretical basis,operation method of Conception Vessel Dredging Therapy and its influence on human health.Through case analysis and the statistical analysis of medical records during the pandemic,it reveals the remarkable effects of this method in regulating the endocrine system,improving metabolism,and relieving physical and mental diseases.It provides a theoretical and practical basis for the application of traditional Chinese medicine anti-aging therapy in the modern health field,and helps to explore new ways to delay aging and improve physical and mental health.展开更多
Accurate and efficient detection of building changes in remote sensing imagery is crucial for urban planning,disaster emergency response,and resource management.However,existing methods face challenges such as spectra...Accurate and efficient detection of building changes in remote sensing imagery is crucial for urban planning,disaster emergency response,and resource management.However,existing methods face challenges such as spectral similarity between buildings and backgrounds,sensor variations,and insufficient computational efficiency.To address these challenges,this paper proposes a novel Multi-scale Efficient Wavelet-based Change Detection Network(MewCDNet),which integrates the advantages of Convolutional Neural Networks and Transformers,balances computational costs,and achieves high-performance building change detection.The network employs EfficientNet-B4 as the backbone for hierarchical feature extraction,integrates multi-level feature maps through a multi-scale fusion strategy,and incorporates two key modules:Cross-temporal Difference Detection(CTDD)and Cross-scale Wavelet Refinement(CSWR).CTDD adopts a dual-branch architecture that combines pixel-wise differencing with semanticaware Euclidean distance weighting to enhance the distinction between true changes and background noise.CSWR integrates Haar-based Discrete Wavelet Transform with multi-head cross-attention mechanisms,enabling cross-scale feature fusion while significantly improving edge localization and suppressing spurious changes.Extensive experiments on four benchmark datasets demonstrate MewCDNet’s superiority over comparison methods:achieving F1 scores of 91.54%on LEVIR,93.70%on WHUCD,and 64.96%on S2Looking for building change detection.Furthermore,MewCDNet exhibits optimal performance on the multi-class⋅SYSU dataset(F1:82.71%),highlighting its exceptional generalization capability.展开更多
BACKGROUND Lumbar interbody fusion(LIF)is the primary treatment for lumbar degenerative diseases.Elderly patients are prone to anxiety and depression after undergoing surgery,which affects their postoperative recovery...BACKGROUND Lumbar interbody fusion(LIF)is the primary treatment for lumbar degenerative diseases.Elderly patients are prone to anxiety and depression after undergoing surgery,which affects their postoperative recovery speed and quality of life.Effective prevention of anxiety and depression in elderly patients has become an urgent problem.AIM To investigate the trajectory of anxiety and depression levels in elderly patients after LIF,and the influencing factors.METHODS Random sampling was used to select 239 elderly patients who underwent LIF from January 2020 to December 2024 in Shenzhen Pingle Orthopedic Hospital.General information and surgery-related indices were recorded,and participants completed measures of psychological status,lumbar spine dysfunction,and quality of life.A latent class growth model was used to analyze the post-LIF trajectory of anxiety and depression levels,and unordered multi-categorical logistic regression was used to analyze the influencing factors.RESULTS Three trajectories of change in anxiety level were identified:Increasing anxiety(n=26,10.88%),decreasing anxiety(n=27,11.30%),and stable anxiety(n=186,77.82%).Likewise,three trajectories of change in depression level were identified:Increasing depression(n=30,12.55%),decreasing depression(n=26,10.88%),and stable depression(n=183,76.57%).Regression analysis showed that having no partner,female sex,elevated Oswestry dysfunction index(ODI)scores,and reduced 36-Item Short Form Health Survey scores all contributed to increased anxiety levels,whereas female sex,postoperative opioid use,and elevated ODI scores all contributed to increased depression levels.CONCLUSION During clinical observation,combining factors to predict anxiety and depression in post-LIF elderly patients enables timely intervention,quickens recovery,and enhances quality of life.展开更多
This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis...This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis,and Sen's slope estimation methods,historical climate trends(1980-2100)were analyzed,while land cover changes represented human impacts.Future projections were simulated using the MIROC model with Shared Socioeconomic Pathways(SSPs)and the Tank model.Results show that during the past 40 years,air temperature significantly increased(Z=3.93^(***)),while precipitation(Z=-1.54^(*))and river flow(Z=-1.73^(*))both declined.The Khyargas Lake water level dropped markedly(Z=-5.57***).Land cover analysis reveals expanded cropland and impervious areas due to human activity.Under the SSP1.26 scenario,which assumes minimal climate change,air temperature is projected to rise by 2.0℃,precipitation by 21.8 mm,and river discharge by 1.61 m^(3)/s between 2000 and 2100.These findings indicate that both global warming and intensified land use have substantially altered hydrological and climatic processes in the basin,highlighting the vulnerability of western Mongolia's water resources to combined climatic and anthropogenic influence.展开更多
Global warming induced by increased CO_(2) has caused marked changes in the ocean.Previous estimates of ocean salinity change in response to global warming have considerable ambiguity,largely attributable to the diver...Global warming induced by increased CO_(2) has caused marked changes in the ocean.Previous estimates of ocean salinity change in response to global warming have considerable ambiguity,largely attributable to the diverse sensitivities of surface fluxes.This study utilizes data from the Flux-Anomaly-Forced Model Intercomparison Project to investigate how ocean salinity responds to perturbations of surface fluxes.The findings indicate the emergence of a sea surface salinity(SSS)dipole pattern predominantly in the North Atlantic and Pacific fresh pools,driven by surface flux perturbations.This results in an intensification of the“salty gets saltier and fresh gets fresher”SSS pattern across the global ocean.The spatial pattern amplification(PA)of SSS under global warming is estimated to be approximately 11.5%,with surface water flux perturbations being the most significant contributor to salinity PA,accounting for 8.1% of the change after 70 years in experiments since pre-industrial control(piControl).Notably,the zonal-depth distribution of salinity in the upper ocean exhibits lighter seawater above the denser water,with bowed isopycnals in the upper 400 m.This stable stratification inhibits vertical mixing of salinity and temperature.In response to the flux perturbations,there is a strong positive feedback due to consequent freshening.It is hypothesized that under global warming,an SSS amplification of 7.2%/℃ and a mixed-layer depth amplification of 12.5%/℃ will occur in the global ocean.It suggests that the salinity effect can exert a more stable ocean to hinder the downward transfer of heat,which provides positive feedback to future global warming.展开更多
In order to simulate changes in the water quality of the Miyun Reservoir dueto continuous descent of surface water level, a 3-D ecological hydrodynamic model was developedthrough coupling the water quality analysis si...In order to simulate changes in the water quality of the Miyun Reservoir dueto continuous descent of surface water level, a 3-D ecological hydrodynamic model was developedthrough coupling the water quality analysis simulation program (WASP) with the environmental fluiddynamics code (EFDC). The model was then calibrated and verified. Four scenarios (S1, S21, S22 andS23) were simulated using the model. Results show that the water quality of the Miyun Reservoirunder conditions of low surface water level is apparently affected by different amounts of inflowand different total phosphorus (TP) loadings. The chlorophyll-a concentration might exceed 10 μg/Lin many areas of the Miyun Reservoir (This limitative value is seen as a critical value ofeutrophication) when large loadings of TP enter due to the amount of inflow increasing. Results ofscenario S23 indicate that control of TP loadings can decrease chlorophyll-a concentrationeffectively, and the water quality of the Miyun Reservoir will improve or retain its status quo.展开更多
By introducing geological and natural conditions of Shuangtaizi Estuary Wetland,a national nature reserve,and borrowing Landsat5 TM wetland data of the year 1987 and 2005,the core area of Shuangtaizi Estuary Wetland i...By introducing geological and natural conditions of Shuangtaizi Estuary Wetland,a national nature reserve,and borrowing Landsat5 TM wetland data of the year 1987 and 2005,the core area of Shuangtaizi Estuary Wetland is studied,areas of its natural water,mudflat,seepweed beach,culture zone,reservoir and swag,reed field,rice field and non-wetland landscape are respectively analyzed,as well as the changes of wetland community,water quality,waterfowl quantity and species.It is found that the study area is suffering from serious fragmentation of wetland,reducing reed yield,degrading water quality,decreasing bird species and amount,which implies that the degraded wetland environment has imposed threats on the survival of some wetland species.Root causes of such a result are analyzed from the perspectives of regional climate changes and human interventions;while regional climate changes include obvious temperature increase and precipitation decrease,human interventions include oil exploration,reclamation of land from the lake,overuse of biotic resources,environment pollution.Due to the interactive influence of these two factors,ecosystem of Shuangtaizi Estuary Wetland has experienced drastic changes,which should be attached sufficient importance by relevant departments so as to enhance its protection and management.展开更多
By analyzing the target's motion pattern, in terms of the requirement for the performance indexes of the follow up system, the structure changing control and time optimal theory is proposed. The system's co...By analyzing the target's motion pattern, in terms of the requirement for the performance indexes of the follow up system, the structure changing control and time optimal theory is proposed. The system's control scheme from three different aspects(the dynamic response simulation, compound control simulation and dynamic tracking simulation) is also studied. And all the results proved the feasibility of the synthetical utilization of the open loop control, speed decreased control and position closed loop control.展开更多
To provide basic information for studying balancing mechanism of nutrition environment in aquaculture ponds, sediment samples were collected periodically during the breeding process of tilapia in ponds. Then various t...To provide basic information for studying balancing mechanism of nutrition environment in aquaculture ponds, sediment samples were collected periodically during the breeding process of tilapia in ponds. Then various types of nutrient content of the samples were detected and the changing rule was summarized. The results showed that dry weight of the sediment and content of TP, TN and TOC generally presented a trend of first increasing and then decreasing. The main production period of each nutrient was from July to September and the production percentage was close to 80% of the total production. The content of NH4^＋-N increased gradually and reached a peak in early August, then maintained at the peak level. NO2^--N content of the sediment in each pond was basically the same in the earlier aquaculture stage and decreased in middle stage with a big difference, then rose again in the later stage.展开更多
With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect o...With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect on runoff is the key to water safety, under climate warming and fast social-economic developing status. In this study, stable isotopic technology was utilized to analyze the snow meltwater effect on regional hydrological processes, and to declare the response of snow hydrology to climate change and snow cover regime, together with longterm meteorological and hydrological observations, in the headwater of Irtysh River, Chinese Altai Mountains during 1961-2015. The average δ^(18) O values of rainfall, snowfall, meltwater, groundwater and river water for 2014–2015 hydrological year were-10.9‰,-22.3‰,-21.7‰,-15.7‰ and-16.0‰, respectively.The results from stable isotopes, snow melting observation and remote sensing indicated that the meltwater effect on hydrological processes in Kayiertesi River Basin mainly occurred during snowmelt supplying period from April to June. The contribution of meltwater to runoff reached 58.1% during this period, but rainfall, meltwater and groundwater supplied 49.1%, 36.9% and 14.0% of water resource to annual runoff, respectively. With rising air temperature and increasing snowfall in cold season, the snow water equivalent(SWE) had an increasing trend but the snow cover duration declined by about one month including 13-day delay of the first day and 17-day advancement of the end day during 1961–2016. Increase in SWE provided more available water resource. However, variations in snow cover timing had resulted in redistribution of surface water resource, represented by an increase of discharge percentage in April and May, and a decline in Juneand July. This trend of snow hydrology will render a deficit of water resource in June and July when the water resource demand is high for agricultural irrigation and industrial manufacture.展开更多
Quantitative characterization of environmental characteristics of cropland(ECC)plays an important role in maintaining sustainable development of agricultural systems and ensuring regional food security. In this study,...Quantitative characterization of environmental characteristics of cropland(ECC)plays an important role in maintaining sustainable development of agricultural systems and ensuring regional food security. In this study, the changes in ECC over the Songnen Plain, a major grain crops production region in Northeast China, were investigated for the period 1990–2015. The results revealed significant changes in climate conditions, soil physical properties and cropland use patterns with socioeconomic activities. Trends in climate parameters showed increasing temperature(+0.49°C/decade, p < 0.05) and decreasing wind speed(–0.3 m/s/decade, p < 0.01) for the growing season, while sunshine hours and precipitation exhibited non-significant trends. Four topsoil parameters including soil organic carbon(SOC), clay, bulk density and pH, indicated deteriorating soil conditions across most of the croplands, although some do exhibited slight improvement. The changing amplitude for each of the four above parameters ranged within –0.052 to 0.029 kg C/kg, –0.38 to 0.30,–0.60 to 0.39 g/cm^3, –3.29 to 2.34, respectively. Crop production significantly increased(44.0 million tons) with increasing sown area of croplands(～2.5 million ha) and fertilizer application(～2.5 million tons). The study reveals the dynamics of ECC in the Songnen Plain with intensive cultivation from 1990 to 2015. Population growth, economic development, and policy reform are shown to strongly influence the spatiotemporal changes in cropland characteristics.The study potentially provides valuable scientific information to support sustainable agroecosystem management in the context of global climate change and national socioeconomic development.展开更多
Arctic sea ice has significant seasonal variability. Prior to the 2000 s, it retreated about 15% in summer and fully recovered in winter. However, by the year 2007, Arctic sea ice extent experienced a catastrophic dec...Arctic sea ice has significant seasonal variability. Prior to the 2000 s, it retreated about 15% in summer and fully recovered in winter. However, by the year 2007, Arctic sea ice extent experienced a catastrophic decline to about 4.28×10^6 km^2, which was 50% lower than conditions in the 1950 s to the 1970 s(Serreze et al., 2008). That was a record low over the course of the modern satellite record, since 1979(note that the year 2012 became the new record low). This astonishing event drew wide-ranging attention in 2007-2009 during the 4 th International Polar Year. The dramatic decline of sea ice attracts many scientists’ interest and has become the focus of intense research since then. Currently, sea ice retreat is not only appearing around the marginal ice zone, but also in the pack ice inside the central Arctic(Zhao et al., 2018). In fact, premonitory signs had already been seen through other evidence. Before the disintegration of the Soviet Union, US naval submarines had been conducting an extensive survey under the sea ice and taking measurements of sea ice thickness. Their measurements revealed a gradual decrease of ice thickness to 1.8 m during winter by the end of the 20 th century, in contrast to the climatological mean of 3.1 m(Rothrock et al., 1999). However, this alarming result did not draw much attention since the Arctic was still severely cold at that time.展开更多
Located in a monsoon domain,East Asia suffers devastating natural hazards induced by anomalous monsoon behaviors.East Asian monsoon(EAM)research has traditionally been a high priority for the Chinese climate community...Located in a monsoon domain,East Asia suffers devastating natural hazards induced by anomalous monsoon behaviors.East Asian monsoon(EAM)research has traditionally been a high priority for the Chinese climate community and is particularly challenging in a changing climate where the global mean temperature has been rising.Recent advances in studies of the variabilities and mechanisms of the EAM are reviewed in this paper,focusing on the interannual to interdecadal time scales.Some new results have been achieved in understanding the behaviors of the EAM,such as the evolution of the East Asian summer monsoon(EASM),including both its onset and withdrawal over the South China Sea,the changes in the northern boundary activity of the EASM,or the transitional climate zone in East Asia,and the cycle of the EASM and the East Asian winter monsoon and their linkages.In addition,understanding of the mechanism of the EAM variability has improved in several aspects,including the impacts of different types of ENSO on the EAM,the impacts from the Indian Ocean and Atlantic Ocean,and the roles of mid-to high-latitude processes.Finally,some scientific issues regarding our understanding of the EAM are proposed for future investigation.展开更多
The characteristics of ultralow permeability reservoirs changed after waterflooding. Thin- section analysis and scanning electron microscopy （SEM） of core samples from inspection wells indicated that calcite and bar...The characteristics of ultralow permeability reservoirs changed after waterflooding. Thin- section analysis and scanning electron microscopy （SEM） of core samples from inspection wells indicated that calcite and barite were formed in ultralow permeability reservoirs during waterflooding operations. Some asphaltene precipitates on the surface of formation rock would influence the reservoir porosity, permeability, wettability, and electrical properties. In this paper, the changes of physical, electrical, and fluid properties of ultralow permeability reservoirs during waterflooding operations were analyzed. This provides important information to improve waterflooding performance in ultralow permeability reservoirs.展开更多
Due to the deficiencies in the conventional multiple-receiver localization syste,.ns based on direction of arrival （DOA） such as system complexity of interferometer or array and ampli- tude/phase unbalance between m...Due to the deficiencies in the conventional multiple-receiver localization syste,.ns based on direction of arrival （DOA） such as system complexity of interferometer or array and ampli- tude/phase unbalance between multiple receiving channels and constraint on antenna configuration, a new radiated source localization method using the changing rate of phase difference （CRPD） measured by a long baseline interferometer （LBI） only is studied. To solve the strictly nonlinear problem, a two-stage closed-form solution is proposed. In the first stage, the DOA and its changing rate are estimated from the CRPD of each observer by the pseudolinear least square （PLS） method, and then in the second stage, the source position and velocity are found by another PLS minimiza- tion. The bias of the algorithm caused by the correlation between the measurement matrix and the noise in the second stage is analyzed. To reduce this bias, an instrumental variable （IV） method is derived. A weighted IV estimator is given in order to reduce the estimation variance. The proposed method does not need any initial guess and the computation is small. The Cramer-Rao lower bound （CRLB） and mean square error （MSE） are also analyzed. Simulation results show that the proposed method can be close to the CRLB with moderate Gaussian measurement noise.展开更多
文摘Earth is moving through a period of extreme uncertainty as global climates change,natural disasters become more frequent and severe,and governments grapple with the difficulty these issues pose for managing natural resources and people.Nowhere are these challenges more pressing than across the world's drylands,where a combination of hotter drier climates challenge food security,sustainable food production and often fuel unrest and political instability.It is against this backdrop that Fu and Stafford Smith,two global leaders in dryland science draw on>80 years of collective wisdom on drylands to describe how humans and natural processes intersect in an era of global change(Fu and Stafford Smith,2024).
基金supported by the National Natural Science Foundation of China(Grant Nos.42150204 and 2288101)supported by the China National Postdoctoral Program for Innovative Talents(BX20230045)the China Postdoctoral Science Foundation(2023M730279)。
文摘A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and development of the NMI model and then emphasize that the NMI model represents a new tool for identifying the basic physics of how climate change influences mid-to-high latitude weather extremes.The building of the NMI model took place over three main periods.In the 1990s,a nonlinear Schr?dinger(NLS)equation model was presented to describe atmospheric blocking as a wave packet;however,it could not depict the lifetime(10-20 days)of atmospheric blocking.In the 2000s,we proposed an NMI model of atmospheric blocking in a uniform basic flow by making a scale-separation assumption and deriving an eddyforced NLS equation.This model succeeded in describing the life cycle of atmospheric blocking.In the 2020s,the NMI model was extended to include the impact of a changing climate mainly by altering the basic zonal winds and the magnitude of the meridional background potential vorticity gradient(PVy).Model results show that when PVy is smaller,blocking has a weaker dispersion and a stronger nonlinearity,so blocking can be more persistent and have a larger zonal scale and weaker eastward movement,thus favoring stronger weather extremes.However,when PVy is much smaller and below a critical threshold under much stronger winter Arctic warming of global warming,atmospheric blocking becomes locally less persistent and shows a much stronger westward movement,which acts to inhibit local cold extremes.Such a case does not happen in summer under global warming because PVy fails to fall below the critical threshold.Thus,our theory indicates that global warming can render summer-blocking anticyclones and mid-to-high latitude heatwaves more persistent,intense,and widespread.
文摘Making plans is a good idea,but every one's schedule looks differe nt.You may have to talk about your plans before you're able to make some.It could sound like this:You ask,"Do you have plans this Friday night?"If the person already has plans,they may say,"I do.But I'm free on Saturday."If that day doesn't work for you,you can say,"I'm not available that day.How about Sunday after no on?"After you figure out the day and time,mark it on your calendar.
基金funded by USAID’s Community Partnerships to Strengthen Sustainable Development(Compass)Program implemented by U.S.Forest Service International Programs(Grant No.Compass-SA-2023-073).
文摘Protecting rare,endemic,and endangered species requires careful habitat evaluation to set strategic plans for mitigating biodiversity loss and prioritizing conservation goals.The endangered Asian elephant(Elephas maximus)exemplifies the urgent need for targeted conservation efforts,given its challenging habitat conditions.This study examines the impact of climate and land use changes on the suitable habitat distribution of Asian elephants.Utilizing ten predictor variables,including climatic,topographic,and land use data,and employing six ensemble Species Distribution Models(SDMs)alongside Coupled Model Intercomparison Project Phase 6 data,the study estimates spatial changes and potential habitat expansions for Asian elephants across Tropical Asia.Occurrence data were gathered from field surveys in Bangladesh and the Global Biodiversity Information Facility database for Sri Lanka,Myanmar,Bhutan,Cambodia,India,Laos,Nepal,Thailand,and Vietnam.To evaluate habitat suitability,the analysis considered two distinct socioeconomic pathways(SSP 245 and SSP 370)across two future periods(2041–2060 and 2061–2080).Results reveal a strong correlation between isothermality and habitat suitability,with higher isothermality enhancing the habitat conditions for Asian elephants.Among the SDMs,the random forest model demonstrated the highest performance.Projected scenarios indicate significant habitat fragmentation by 2061–2080,heightening the risk of species’vulnerability.Specifically,in SSP 245,the north zone is anticipated to experience a higher rate of habitat loss(588.443 km^(2)/year),whereas,in SSP 370,the west zone is expected to face a more severe rate of habitat loss(1,798.56 km^(2)/year).The eastern zone,which includes Cambodia,Vietnam,Laos,Thailand,and southern Myanmar,is notably at risk,with an estimated habitat loss of 14.8 million hectares.Anticipated changes in climate and land cover will impact the availability of essential resources such as food,water,and shelter,potentially driving the species to relocate to different elevation belts.The outcomes of the consensus map highlighting critical habitats and future fragmentation scenarios will support effective conservation and management strategies for the species.
基金Supported by Natural Science Foundation of China,Taoist Qi Healing the World Project(Project No.:71971359).
文摘This study,based on the theory of shifting essence and changing Qi in Inner Canon of Huangdi,deeply explores the theoretical basis,operation method of Conception Vessel Dredging Therapy and its influence on human health.Through case analysis and the statistical analysis of medical records during the pandemic,it reveals the remarkable effects of this method in regulating the endocrine system,improving metabolism,and relieving physical and mental diseases.It provides a theoretical and practical basis for the application of traditional Chinese medicine anti-aging therapy in the modern health field,and helps to explore new ways to delay aging and improve physical and mental health.
基金supported by the Henan Province Key R&D Project under Grant 241111210400the Henan Provincial Science and Technology Research Project under Grants 252102211047,252102211062,252102211055 and 232102210069+2 种基金the Jiangsu Provincial Scheme Double Initiative Plan JSS-CBS20230474,the XJTLU RDF-21-02-008the Science and Technology Innovation Project of Zhengzhou University of Light Industry under Grant 23XNKJTD0205the Higher Education Teaching Reform Research and Practice Project of Henan Province under Grant 2024SJGLX0126。
文摘Accurate and efficient detection of building changes in remote sensing imagery is crucial for urban planning,disaster emergency response,and resource management.However,existing methods face challenges such as spectral similarity between buildings and backgrounds,sensor variations,and insufficient computational efficiency.To address these challenges,this paper proposes a novel Multi-scale Efficient Wavelet-based Change Detection Network(MewCDNet),which integrates the advantages of Convolutional Neural Networks and Transformers,balances computational costs,and achieves high-performance building change detection.The network employs EfficientNet-B4 as the backbone for hierarchical feature extraction,integrates multi-level feature maps through a multi-scale fusion strategy,and incorporates two key modules:Cross-temporal Difference Detection(CTDD)and Cross-scale Wavelet Refinement(CSWR).CTDD adopts a dual-branch architecture that combines pixel-wise differencing with semanticaware Euclidean distance weighting to enhance the distinction between true changes and background noise.CSWR integrates Haar-based Discrete Wavelet Transform with multi-head cross-attention mechanisms,enabling cross-scale feature fusion while significantly improving edge localization and suppressing spurious changes.Extensive experiments on four benchmark datasets demonstrate MewCDNet’s superiority over comparison methods:achieving F1 scores of 91.54%on LEVIR,93.70%on WHUCD,and 64.96%on S2Looking for building change detection.Furthermore,MewCDNet exhibits optimal performance on the multi-class⋅SYSU dataset(F1:82.71%),highlighting its exceptional generalization capability.
基金Supported by the Scientific Research Projects of the Health System in Pingshan District,No.2023122.
文摘BACKGROUND Lumbar interbody fusion(LIF)is the primary treatment for lumbar degenerative diseases.Elderly patients are prone to anxiety and depression after undergoing surgery,which affects their postoperative recovery speed and quality of life.Effective prevention of anxiety and depression in elderly patients has become an urgent problem.AIM To investigate the trajectory of anxiety and depression levels in elderly patients after LIF,and the influencing factors.METHODS Random sampling was used to select 239 elderly patients who underwent LIF from January 2020 to December 2024 in Shenzhen Pingle Orthopedic Hospital.General information and surgery-related indices were recorded,and participants completed measures of psychological status,lumbar spine dysfunction,and quality of life.A latent class growth model was used to analyze the post-LIF trajectory of anxiety and depression levels,and unordered multi-categorical logistic regression was used to analyze the influencing factors.RESULTS Three trajectories of change in anxiety level were identified:Increasing anxiety(n=26,10.88%),decreasing anxiety(n=27,11.30%),and stable anxiety(n=186,77.82%).Likewise,three trajectories of change in depression level were identified:Increasing depression(n=30,12.55%),decreasing depression(n=26,10.88%),and stable depression(n=183,76.57%).Regression analysis showed that having no partner,female sex,elevated Oswestry dysfunction index(ODI)scores,and reduced 36-Item Short Form Health Survey scores all contributed to increased anxiety levels,whereas female sex,postoperative opioid use,and elevated ODI scores all contributed to increased depression levels.CONCLUSION During clinical observation,combining factors to predict anxiety and depression in post-LIF elderly patients enables timely intervention,quickens recovery,and enhances quality of life.
基金The National University of Mongolia,No.P2024-4814The Mongolian Science and Technology Foundation,No.CHN-2022/274The‘Chey Institute for Advanced Studies’International Scholar Exchange Fellowship for the Academic Year of 2025-2026。
文摘This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis,and Sen's slope estimation methods,historical climate trends(1980-2100)were analyzed,while land cover changes represented human impacts.Future projections were simulated using the MIROC model with Shared Socioeconomic Pathways(SSPs)and the Tank model.Results show that during the past 40 years,air temperature significantly increased(Z=3.93^(***)),while precipitation(Z=-1.54^(*))and river flow(Z=-1.73^(*))both declined.The Khyargas Lake water level dropped markedly(Z=-5.57***).Land cover analysis reveals expanded cropland and impervious areas due to human activity.Under the SSP1.26 scenario,which assumes minimal climate change,air temperature is projected to rise by 2.0℃,precipitation by 21.8 mm,and river discharge by 1.61 m^(3)/s between 2000 and 2100.These findings indicate that both global warming and intensified land use have substantially altered hydrological and climatic processes in the basin,highlighting the vulnerability of western Mongolia's water resources to combined climatic and anthropogenic influence.
基金supported by the Laoshan Laboratory[grant number LSKJ202202403]the National Natural Science Foundation of China[grant number 42030410]+1 种基金additionally supported by the Startup Foundation for Introducing Talent of NUISTJiangsu Innovation Research Group[grant number JSSCTD202346]。
文摘Global warming induced by increased CO_(2) has caused marked changes in the ocean.Previous estimates of ocean salinity change in response to global warming have considerable ambiguity,largely attributable to the diverse sensitivities of surface fluxes.This study utilizes data from the Flux-Anomaly-Forced Model Intercomparison Project to investigate how ocean salinity responds to perturbations of surface fluxes.The findings indicate the emergence of a sea surface salinity(SSS)dipole pattern predominantly in the North Atlantic and Pacific fresh pools,driven by surface flux perturbations.This results in an intensification of the“salty gets saltier and fresh gets fresher”SSS pattern across the global ocean.The spatial pattern amplification(PA)of SSS under global warming is estimated to be approximately 11.5%,with surface water flux perturbations being the most significant contributor to salinity PA,accounting for 8.1% of the change after 70 years in experiments since pre-industrial control(piControl).Notably,the zonal-depth distribution of salinity in the upper ocean exhibits lighter seawater above the denser water,with bowed isopycnals in the upper 400 m.This stable stratification inhibits vertical mixing of salinity and temperature.In response to the flux perturbations,there is a strong positive feedback due to consequent freshening.It is hypothesized that under global warming,an SSS amplification of 7.2%/℃ and a mixed-layer depth amplification of 12.5%/℃ will occur in the global ocean.It suggests that the salinity effect can exert a more stable ocean to hinder the downward transfer of heat,which provides positive feedback to future global warming.
文摘In order to simulate changes in the water quality of the Miyun Reservoir dueto continuous descent of surface water level, a 3-D ecological hydrodynamic model was developedthrough coupling the water quality analysis simulation program (WASP) with the environmental fluiddynamics code (EFDC). The model was then calibrated and verified. Four scenarios (S1, S21, S22 andS23) were simulated using the model. Results show that the water quality of the Miyun Reservoirunder conditions of low surface water level is apparently affected by different amounts of inflowand different total phosphorus (TP) loadings. The chlorophyll-a concentration might exceed 10 μg/Lin many areas of the Miyun Reservoir (This limitative value is seen as a critical value ofeutrophication) when large loadings of TP enter due to the amount of inflow increasing. Results ofscenario S23 indicate that control of TP loadings can decrease chlorophyll-a concentrationeffectively, and the water quality of the Miyun Reservoir will improve or retain its status quo.
基金Supported by National Natural Science Foundation(40871259)~~
文摘By introducing geological and natural conditions of Shuangtaizi Estuary Wetland,a national nature reserve,and borrowing Landsat5 TM wetland data of the year 1987 and 2005,the core area of Shuangtaizi Estuary Wetland is studied,areas of its natural water,mudflat,seepweed beach,culture zone,reservoir and swag,reed field,rice field and non-wetland landscape are respectively analyzed,as well as the changes of wetland community,water quality,waterfowl quantity and species.It is found that the study area is suffering from serious fragmentation of wetland,reducing reed yield,degrading water quality,decreasing bird species and amount,which implies that the degraded wetland environment has imposed threats on the survival of some wetland species.Root causes of such a result are analyzed from the perspectives of regional climate changes and human interventions;while regional climate changes include obvious temperature increase and precipitation decrease,human interventions include oil exploration,reclamation of land from the lake,overuse of biotic resources,environment pollution.Due to the interactive influence of these two factors,ecosystem of Shuangtaizi Estuary Wetland has experienced drastic changes,which should be attached sufficient importance by relevant departments so as to enhance its protection and management.
文摘By analyzing the target's motion pattern, in terms of the requirement for the performance indexes of the follow up system, the structure changing control and time optimal theory is proposed. The system's control scheme from three different aspects(the dynamic response simulation, compound control simulation and dynamic tracking simulation) is also studied. And all the results proved the feasibility of the synthetical utilization of the open loop control, speed decreased control and position closed loop control.
基金Supported by Fundamental Research Funds in Central Public Welfare Research Institutes(2015JBFM28)National Agriculture Industrial Technology(CARS-49)~~
文摘To provide basic information for studying balancing mechanism of nutrition environment in aquaculture ponds, sediment samples were collected periodically during the breeding process of tilapia in ponds. Then various types of nutrient content of the samples were detected and the changing rule was summarized. The results showed that dry weight of the sediment and content of TP, TN and TOC generally presented a trend of first increasing and then decreasing. The main production period of each nutrient was from July to September and the production percentage was close to 80% of the total production. The content of NH4^＋-N increased gradually and reached a peak in early August, then maintained at the peak level. NO2^--N content of the sediment in each pond was basically the same in the earlier aquaculture stage and decreased in middle stage with a big difference, then rose again in the later stage.
基金funded by the Chinese Academy of Sciences (KJZD-EW-G03-04, QYZDJSSW-DQC039)the National Science Foundation of China (NSFC 41630754, 41690144, 41421061)the Foundation of the State Key Laboratory of Cryospheric Sciences (SKLCS) at Northwest Institute of Eco-Environment and Resources (NIEER), CAS (SKLCS-OP-2017-10, SKLCS-ZZ2016)
文摘With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect on runoff is the key to water safety, under climate warming and fast social-economic developing status. In this study, stable isotopic technology was utilized to analyze the snow meltwater effect on regional hydrological processes, and to declare the response of snow hydrology to climate change and snow cover regime, together with longterm meteorological and hydrological observations, in the headwater of Irtysh River, Chinese Altai Mountains during 1961-2015. The average δ^(18) O values of rainfall, snowfall, meltwater, groundwater and river water for 2014–2015 hydrological year were-10.9‰,-22.3‰,-21.7‰,-15.7‰ and-16.0‰, respectively.The results from stable isotopes, snow melting observation and remote sensing indicated that the meltwater effect on hydrological processes in Kayiertesi River Basin mainly occurred during snowmelt supplying period from April to June. The contribution of meltwater to runoff reached 58.1% during this period, but rainfall, meltwater and groundwater supplied 49.1%, 36.9% and 14.0% of water resource to annual runoff, respectively. With rising air temperature and increasing snowfall in cold season, the snow water equivalent(SWE) had an increasing trend but the snow cover duration declined by about one month including 13-day delay of the first day and 17-day advancement of the end day during 1961–2016. Increase in SWE provided more available water resource. However, variations in snow cover timing had resulted in redistribution of surface water resource, represented by an increase of discharge percentage in April and May, and a decline in Juneand July. This trend of snow hydrology will render a deficit of water resource in June and July when the water resource demand is high for agricultural irrigation and industrial manufacture.
基金National Natural Science Foundation of China,No.41571410,No.41571199,No.41401589
文摘Quantitative characterization of environmental characteristics of cropland(ECC)plays an important role in maintaining sustainable development of agricultural systems and ensuring regional food security. In this study, the changes in ECC over the Songnen Plain, a major grain crops production region in Northeast China, were investigated for the period 1990–2015. The results revealed significant changes in climate conditions, soil physical properties and cropland use patterns with socioeconomic activities. Trends in climate parameters showed increasing temperature(+0.49°C/decade, p < 0.05) and decreasing wind speed(–0.3 m/s/decade, p < 0.01) for the growing season, while sunshine hours and precipitation exhibited non-significant trends. Four topsoil parameters including soil organic carbon(SOC), clay, bulk density and pH, indicated deteriorating soil conditions across most of the croplands, although some do exhibited slight improvement. The changing amplitude for each of the four above parameters ranged within –0.052 to 0.029 kg C/kg, –0.38 to 0.30,–0.60 to 0.39 g/cm^3, –3.29 to 2.34, respectively. Crop production significantly increased(44.0 million tons) with increasing sown area of croplands(～2.5 million ha) and fertilizer application(～2.5 million tons). The study reveals the dynamics of ECC in the Songnen Plain with intensive cultivation from 1990 to 2015. Population growth, economic development, and policy reform are shown to strongly influence the spatiotemporal changes in cropland characteristics.The study potentially provides valuable scientific information to support sustainable agroecosystem management in the context of global climate change and national socioeconomic development.
基金Funding was provided by Global Change Research Program of China (No. 2015CB953900)the Key Project of the National Natural Science Foundation of China (No. 41330960)
文摘Arctic sea ice has significant seasonal variability. Prior to the 2000 s, it retreated about 15% in summer and fully recovered in winter. However, by the year 2007, Arctic sea ice extent experienced a catastrophic decline to about 4.28×10^6 km^2, which was 50% lower than conditions in the 1950 s to the 1970 s(Serreze et al., 2008). That was a record low over the course of the modern satellite record, since 1979(note that the year 2012 became the new record low). This astonishing event drew wide-ranging attention in 2007-2009 during the 4 th International Polar Year. The dramatic decline of sea ice attracts many scientists’ interest and has become the focus of intense research since then. Currently, sea ice retreat is not only appearing around the marginal ice zone, but also in the pack ice inside the central Arctic(Zhao et al., 2018). In fact, premonitory signs had already been seen through other evidence. Before the disintegration of the Soviet Union, US naval submarines had been conducting an extensive survey under the sea ice and taking measurements of sea ice thickness. Their measurements revealed a gradual decrease of ice thickness to 1.8 m during winter by the end of the 20 th century, in contrast to the climatological mean of 3.1 m(Rothrock et al., 1999). However, this alarming result did not draw much attention since the Arctic was still severely cold at that time.
基金supported jointly by the National Key Research and Development Program(Grant No.2016YFA0600604)the National Natural Science Foundation of China(Grant No.41721004)+1 种基金the Chinese Academy of Sciences Key Research Program of Frontier Sciences(Grant No.QYZDY-SSW-DQC024)the Jiangsu Collaborative Innovation Center for Climate Change
文摘Located in a monsoon domain,East Asia suffers devastating natural hazards induced by anomalous monsoon behaviors.East Asian monsoon(EAM)research has traditionally been a high priority for the Chinese climate community and is particularly challenging in a changing climate where the global mean temperature has been rising.Recent advances in studies of the variabilities and mechanisms of the EAM are reviewed in this paper,focusing on the interannual to interdecadal time scales.Some new results have been achieved in understanding the behaviors of the EAM,such as the evolution of the East Asian summer monsoon(EASM),including both its onset and withdrawal over the South China Sea,the changes in the northern boundary activity of the EASM,or the transitional climate zone in East Asia,and the cycle of the EASM and the East Asian winter monsoon and their linkages.In addition,understanding of the mechanism of the EAM variability has improved in several aspects,including the impacts of different types of ENSO on the EAM,the impacts from the Indian Ocean and Atlantic Ocean,and the roles of mid-to high-latitude processes.Finally,some scientific issues regarding our understanding of the EAM are proposed for future investigation.
基金the financial support from the major science and technology project of Petrochina(Key Technology Study of Stable Production and Enhanced Oil Recovery in the Changqing Oil field.No.2011E-1305)
文摘The characteristics of ultralow permeability reservoirs changed after waterflooding. Thin- section analysis and scanning electron microscopy （SEM） of core samples from inspection wells indicated that calcite and barite were formed in ultralow permeability reservoirs during waterflooding operations. Some asphaltene precipitates on the surface of formation rock would influence the reservoir porosity, permeability, wettability, and electrical properties. In this paper, the changes of physical, electrical, and fluid properties of ultralow permeability reservoirs during waterflooding operations were analyzed. This provides important information to improve waterflooding performance in ultralow permeability reservoirs.
基金co-supported by the Foundation of National Defense Key Laboratory of China (No. 9140C860304)the National High Technology Research and Development Program of China (No. 2011AA7072048)
文摘Due to the deficiencies in the conventional multiple-receiver localization syste,.ns based on direction of arrival （DOA） such as system complexity of interferometer or array and ampli- tude/phase unbalance between multiple receiving channels and constraint on antenna configuration, a new radiated source localization method using the changing rate of phase difference （CRPD） measured by a long baseline interferometer （LBI） only is studied. To solve the strictly nonlinear problem, a two-stage closed-form solution is proposed. In the first stage, the DOA and its changing rate are estimated from the CRPD of each observer by the pseudolinear least square （PLS） method, and then in the second stage, the source position and velocity are found by another PLS minimiza- tion. The bias of the algorithm caused by the correlation between the measurement matrix and the noise in the second stage is analyzed. To reduce this bias, an instrumental variable （IV） method is derived. A weighted IV estimator is given in order to reduce the estimation variance. The proposed method does not need any initial guess and the computation is small. The Cramer-Rao lower bound （CRLB） and mean square error （MSE） are also analyzed. Simulation results show that the proposed method can be close to the CRLB with moderate Gaussian measurement noise.
