•Developed a decomposition method for simulating layered vegetation coverage.•Simulated layered PAI and COVER continuity maps by combining SOFM and RF model.•In Jiangxi Province, more than 80% of ...forestland is under 20 m in height.•PAI and COVER both show an upward-then-downward trend with height, peaking at 5–10 m.
The spatially continuous mapping of vegetation structure parameters in forested areas serves as a crucial foundation for research in various fields, including ecosystem ecology, climate change, hydrology, and forest management and protection. However, there is a notable scarcity of regional scale data regarding vegetation structure parameters. Therefore, our objective was to fill this data gap by providing a methodology for mapping vegetation structure parameters in forested areas at regional-scale. Global Ecosystem Dynamics Investigation (GEDI) provides precise observational data on vegetation structure parameters across the world. Using GEDI vegetation structure parameter point data, we developed a vegetation state coefficient based on the ratio of plant area index (PAI) and vegetation coverage (COVER). Subsequently, we proposed a method for decomposing vegetation coverage to simulate layered vegetation coverage. Taking Jiangxi Province as a case study, we integrated machine learning models to generate a spatially continuous map of vegetation structure parameters in forested areas, including layered coverage and layered leaf area index, in 2020. The map has a spatial resolution of 30 m and a vertical resolution of 5 m. The model exhibits excellent performance. Among the 140 sets of models, approximately 63 % of them achieved an R2 surpassing 0.6, while 89 % of the models achieved a root mean square error (RMSE) below 0.3. This study can serve as a valuable reference for the decomposition of vegetation structure parameters at the regional scale and provide a more precise depiction of the spatial characteristics of vertical vegetation structure at the regional scale. It contributes by providing data support and methodological guidance for research related to forest structure analysis, resource management, and ecological process simulation at the regional scale.
•We analyzed the spatiotemporal dynamics of urban expansion in Northeast China from different scales.•The impact of urban expansion on cropland productivity showed significant spatial ...heterogeneity.•Urban expansion brought pressure to food security in the Northeast region.
Urban development inevitably comes with the loss of prime agricultural land, leading to a decline in cropland productivity. The Northeast region is an important grain-producing region in China, and agricultural land is of great significance in ensuring national food security. Here, land use and cover data and MODIS-NPP data were used to comprehensively understand the direct and adverse influence of urban land growth on cropland net primary productivity (NPP) in Northeast China. The results indicated that (1) in Northeast China, the urban land area increased by a total of 5230.00 km2 since 2000. The urban land growth phenomenon was particularly notable in the cities near the central transportation trunk line and along the southern coastal regions. (2) more than half of the newly added urban land patches originated from cropland. Between 2000 and 2020, urban expansion in Northeast China resulted in a 0. 85 Tg C loss of cropland NPP. (3) there was significant regional variation in cropland NPP loss. The low altitude and low slope regions experienced the most significant NPP loss. Meanwhile, large and developed cities caused more NPP losses, and cities with dispersed expansion had a broader impact on cropland productivity than cities with concentrated expansion. (4) when converting the loss of cropland NPP to crop yield, it revealed a reduction of 0.91 million tons in grain yield in Northeast China. These findings provide valuable insights for urban development and cropland protection strategies in Northeast China, offering crucial guidance for sustainable land use practices.
The Southwest China Karst, the largest continuous karst zone in the world, has suffered serious rock desertification due to the large population pressure in the area. Recent trend analyses have ...indicated general greening trends in this region. The region has experienced mild climate change, and yet significant land use changes, such as afforestation and reforestation. In addition, out-migration has occurred. Whether climate change or human-induced factors, i.e., ecological afforestation projects and out-migration have primarily promoted forest restoration in this region was investigated in this study, using Guizhou Province as the study area. Based on Moderate-Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data, we found general greening trends of the forest from 2000 to 2010. About 89% of the forests have experienced an increase in the annual NDVI, and among which, about 41% is statistically significant. For the summer season, more than 65% of the forests have increases in summer NDVI, and about 16% of the increases are significant. The strongest greening trends mainly occurred in the karst areas. Meanwhile, annual average and summer average temperature in this region have increased and the precipitation in most of the region has decreased, although most of these changes were not statistically significant (p > 0.1). A site-based regression analysis using 19 climate stations with minimum land use changes showed that a warming climate coupled with a decrease in precipitation explained some of the changes in the forest NDVI, but the results were not conclusive. The major changes were attributed to human-induced factors, especially in the karst areas. The implications of an ecological afforestation project and out-migration for forest restoration were also discussed, and the need for further investigations at the household level to better understand the out-migration-environment relationship was identified.
China has experienced greater and faster urbanization than any other country, and while coordinated regional development has been promoted, urbanization has also introduced various problems, such as ...an increased scarcity of land resources, uncontrolled demand for urban land, and disorderly development of urban fringes. Based on GIS, remote sensing data, and spatial statistics covering the period 1995–2015, this study identified the patterns, as well as spatial and temporal changes, with respect to urban land expansion in 367 mainland Chinese cities. Over this study period, the area of urban land in mainland China increased from 3.05 to 5.07 million km2, at an average annual growth rate of 2.56%. This urban land expansion typically occurred the fastest in medium-sized cities, followed by large cities, and then small cities, with megacities and megalopolises exhibiting the slowest expansion rates. Nearly 70% of the new urban land came from arable land, 11% from other built land, such as pre-existing rural settlements, and 15% from forests and grasslands. When considering marginal-, enclave-, and infill-type expansion patterns, growth in >80% of the 367 cities surveyed was dominated by marginal expansion patterns. Marginal and enclave expansion patterns were found to be becoming more prevalent, with infill-type expansion being seen less. The results of this study provide a theoretical basis and data support for urban spatial planning, the protection of farmland, and the promotion of urban land use efficiency, and can be used as guidance for regional urbanization planning.
Urban green space (UGS) can be regarded as an effective approach to mitigate urban heat island (UHI) effects. Many studies have investigated the impacts of composition and configuration of UGS on ...land surface temperature (LST), while little attention has been paid to the impacts among different urban blocks. Thus, taking 1835 urban blocks in Beijing as samples, including low-rise point (LRP), low-rise street (LRS), low-rise block (LRB), mid-rise point (MRP), mid-rise street (MRS), mid-rise block (MRB), high-rise point (HRP), high-rise street (HRS) and high-rise block (HRB), this study investigated the impacts of UGS on LST among different urban blocks. The results showed that UGS serves as cold islands among different urban blocks. Percentage of landscape (PLAND) of UGS in all types of urban blocks, edge density (ED) of UGS in MRS, area-weighted fractal dimension index (FRAC_AM) of UGS in HRS and HRB show significantly negative impacts on LST, while aggregation index (AI) of UGS in LRP shows significantly positive impacts. The findings suggest that both composition and configuration of UGS can affect LST among different urban blocks and rational allocation of UGS would be effective for mitigating UHI effects.
► The effect of ethylene oxide groups was studied. ► Both of GC16 (3) and GC20 (5) could reduce DIFT to low value. ► When the mass ratio of GC16 (3)/GC20 (5) was 9:1, the DIFT could reach ultralow ...value. ► The GC16 (3)/GC20 (5) compound system showed a certain temperature resistance.
In the surfactant flooding systems for enhanced oil recovery, interfacial tension between surfactant solution and crude oil should be decreased to ultralow value (<10−2mNm−1). Accordingly, in this paper, the dynamic interfacial tension behaviors between Guerbet betaine surfactants solution and Daqing crude oil were studied. The influence factors such as ethylene oxide groups, surfactant concentration, and the mass ratio of compound systems, sodium carbonate concentration and temperature were investigated. It was found that the prepared surfactants used alone cannot reduce the dynamic interfacial tension to ultralow value. In order to meet the demand, the compound systems were taken into account. The results showed that the effect of GC16 (3)/GC20 (5) compound system was better than GC16 (3)/GC18 (5) and GC20 (5)/GC18 (5). When the mass ratio of GC16 (3)/GC20 (5) was 9:1, the dynamic interfacial tension can reach ultralow value. Then the effect of sodium carbonate concentration and temperature were studied for this better compound system (GC16 (3)/GC20 (5)=9:1), the results showed that this compound system existed an optimum sodium carbonate concentration and exhibited good temperature resistance.
Rainfall and land use conversion are important factors influencing soil erosion. Differing from the stationary land use type, land use conversion is a process of dynamic change usually spanning ...several decades. Soil erosion modeling using historic land use data offers an opportunity to study the impacts of actual land use conversion on soil erosion. However, rainfall has been taken into account only in a few studies because its spatio-temporal distribution often varies greatly over a long period of time. In this article, the erosivity index was used to quantify the erosive force of rainfall. Based on entropy theory, erosivity distribution of study area during the 1988 to 2013 period was analyzed. Two extreme zones, Zone I and Zone II, with highest and lowest annual erosivity, respectively, were identified. The intensity of soil erosion among land use types are: farmland>orchard>grass/open forest>shrub>forest. Zone I has severer soil erosion than Zone II. The effectiveness of land use conversion for reducing soil erosion varies between different erosivity zones. Farmland–forest conversion is considered as the first choice to reduce soil erosion when land use conversion is implemented. The conversions of farmland–grassland and farmland–open forest can be used as important supplements to conversion of farmland–forest in low erosivity zone of the study area, although they do not perform well under higher erosivity situation.
•Entropy theory was used to assess the distribution of rainfall erosivity.•Two extreme rainfall erosivity zones were identified.•The effectiveness of land use conversion for reducing soil erosion varies between different zones.•Farmland–forest conversion is considered as the first choice to reduce soil erosion.•Entropy combinated with RUSLE can study the effect of rainfall and land use conversion on soil erosion.
The research on the grid size suitability is important to provide improvement in accuracies of gridded population distribution. It contributes to reveal the actual spatial distribution of population. ...However, currently little research has been done in this area. Many well-modeled gridded population dataset are basically built at a single grid scale. If the grid cell size is not appropriate, it will result in spatial information loss or data redundancy. Therefore, in order to capture the desired spatial variation of population within the area of interest, it is necessary to conduct research on grid size suitability. This study summarized three expressed levels to analyze grid size suitability, which include location expressed level, numeric information expressed level, and spatial relationship expressed level. This study elaborated the reasons for choosing the five indexes to explore expression suitability. These five indexes are consistency measure, shape index rate, standard deviation of population density, patches diversity index, and the average local variance. The suitable grid size was determined by constructing grid size-indicator value curves and suitable grid size scheme. Results revealed that the three expressed levels on 10m grid scale are satisfying. And the population distribution raster data with 10m grid size provide excellent accuracy without loss. The 10m grid size is recommended as the appropriate scale for generating a high-quality gridded population distribution in our study area. Based on this preliminary study, it indicates the five indexes are coordinated with each other and reasonable and effective to assess grid size suitability. We also suggest choosing these five indexes in three perspectives of expressed level to carry out the research on grid size suitability of gridded population distribution.
•Winter streamflow increases were 1.7–5.2 times greater than annual streamflow.•Discharge in late winter is the lowest but is most sensitive to temperature.•The early winter streamflow reflects the ...changes in late summer precipitation.•Permafrost thawing gradually increases the winter streamflow.
The increasing winter streamflow of major Arctic rivers has been well documented. However, the contribution of climate change to winter streamflow and associated mechanisms of streamflow generation during early, mid- and late winter are not fully understood. Among the Arctic rivers, we selected four rivers with relatively few dam effects (Lena, Kolyma, Yukon and Mackenzie rivers) and analysed their climate change-related responses in streamflow during early, mid-, and late winter. Our results showed that the winter streamflow (Qwin) of the Lena, Kolyma, Yukon and Mackenzie rivers increased from 1980 to 2019 by approximately 43%, 72%, 16% and 16% (1.7–5.2 times greater than increases in annual streamflow), respectively. In general, the rate of streamflow increase was the greatest in early winter, followed by mid- and late winter. The streamflow in late winter was particularly sensitive to air temperature changes, and permafrost degradation due to rising temperatures is likely a major factor driving late winter streamflow increases. In contrast to late winter streamflow, the larger rate of increase in early winter streamflow can be mainly attributed to the additional influence of increased late summer precipitation on streamflow generation. The different change rates in winter streamflow among the four river basins are highly determined by permafrost degradation and related baseflow discharge processes. Under warming climate conditions, winter streamflow generation is strongly associated with the enhanced hydrological cycle that is apparent in both the surface (e.g., precipitation and river ice) and the subsurface (the active layer and groundwater discharge).
Acute ST-segment elevation myocardial infarction (STEMI) remains a serious life threatening event with a poor prognosis due to myocardial ischemia/reperfusion injury despite coronary ...revascularization. Extracorporeal cardiac shock wave (ECSW) is a safe, effective and non-invasive new method for the treatment of cardiovascular diseases. The current results show that extracorporeal cardiac shock wave provides a new treatment option for patients with severe and advanced coronary heart disease. However, there are relatively few clinical studies on the application of in vitro cardiac shock waves in patients with myocardial ischemia-reperfusion injury. We hypothesized that extracorporeal cardiac shock therapy would also be effective in reducing clinical endpoints in patients with STEMI reperfusion.
This study is order to provide a new therapeutic method for patients with myocardial ischemia-reperfusion injury and reveal the possible mechanism of ECSW for ischemia-reperfusion injury.
CEECSWIIRI is a single-center, prospective randomized controlled trial that plans to enroll 102 eligible patients with acute ST-segment elevation myocardial infarction reperfusion. Eligible patients with STEMI reperfusion will be randomly divided into external cardiac shock therapy (ECSW) trial group and blank control group. The blank control group will receive optimal drug therapy, and the experimental group will receive optimal drug therapy combined with ECSW. The shock wave treatment plan will be 3-month therapy, specifically 1 week of treatment per month, 3 weeks of rest, 3 times of ECSW in each treatment week, respectively on the first day, the third day and the fifth day of the treatment week, lasting for 3 months and follow-up for 2 years. The primary endpoint will be to assess the 2-year improvement in all-cause death, re-hospitalization due to cardiovascular disease, major unintentional cerebrovascular events, including cardiogenic death, myocardial infarction, heart failure, arrhythmia, emergency coronary revascularization, and stroke in patients with STEMI reperfusion. Secondary endpoints will include improvements in angina pectoris, quality of life, cardiac structure and function, coronary microcirculation, and endothelial progenitor cell-derived miR-140-3p in relation to survival outcomes.
ClinicalTrial.gov.org PRS:NCT05624203; Date of registration: November 12, 2022.
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