Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for t...Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for the IS in Beijing metropolitan region. However, most previous studies primarily considered the Beijing metropolitan region as a whole without considering the differences and heterogeneity among the function zones. In this study, the subpixel impervious surface results in Beijing within a time series(1991, 2001, 2005, 2011 and 2015) were extracted by means of the classification and regression tree(CART) model combined with change detection models. Then based on the method of standard deviation ellipse, Lorenz curve, contribution index(CI) and landscape metrics, the spatio-temporal dynamics and variations of IS(1991, 2001, 2011 and 2015) in different function zones and districts were analyzed. It is found that the total area of impervious surface in Beijing increased dramatically during the study period, increasing about 144.18%. The deflection angle of major axis of standard deviation ellipse decreased from 47.15° to 38.82°, indicating the major development axis in Beijing gradually moved from northeast-southwest to north-south. Moreover, the heterogeneity of impervious surface’s distribution among 16 districts weakened gradually, but the CI values and landscape metrics in four function zones differed greatly. The urban function extended zone(UFEZ), the main source of the growth of IS in Beijing, had the highest CI values. Its lowest CI value was 1.79 that is still much higher than the highest CI value in other function zones. The core function zone(CFZ), the traditional aggregation zone of impervious surface, had the highest contagion index(CONTAG) values, but it contributed less than UFEZ due to its small area. The CI value of the new urban developed zone(NUDZ) increased rapidly, and it increased from negative to positive and multiplied, becoming animportant contributor to the rise of urban impervious surface. However, the ecological conservation zone(ECZ) had a constant negative contribution all the time, and its CI value decreased gradually. Moreover, the landscape metrics and centroids of impervious surface in different density classes differed greatly. The high-density impervious surface had a more compact configuration and a greater impact on the eco-environment.展开更多
Urbanization significantly increases the risk of urban flooding. Therefore, quantitative study of urban rainfall-runoff processes can provide a scientific basis for urban planning and management. In this paper, the bu...Urbanization significantly increases the risk of urban flooding. Therefore, quantitative study of urban rainfall-runoff processes can provide a scientific basis for urban planning and management. In this paper, the built-up region within the Fifth Ring Road of Beijing was selected as the study area. The details of land cover and urban function zones(UFZs) were identified using GIS and RS methods. On this basis, the SCS-CN model was adopted to analyze the rainfall-runoff risk characteristics of the study area. The results showed that:(1) UFZs within different levels of runoff risk varied under different rainfall conditions. The area ratio of the UFZs with high runoff risk increased from 18.90%(for rainfall return period of 1 a) to 54.74%(for period of 100 a). Specifically, urban commercial areas tended to have the highest runoff risk, while urban greening spaces had the lowest.(2) The spatial characteristics of the runoff risks showed an obvious circular distribution. Spatial cluster areas with high runoff risk were mainly concentrated in the center of the study area, while those with low runoff risk were mainly distributed between the fourth and fifth ring roads. The results indicated that the spatial clustering characteristic of urban runoff risk and runoff heterogeneity among different UFZs should be fully considered during urban rainwater management.展开更多
The implementation of Ecological Function Protection Zone(EFPZ)policy is significant for the ecological restoration and conservation of soil and water in the territory space.This manuscript analyzed and quantified the...The implementation of Ecological Function Protection Zone(EFPZ)policy is significant for the ecological restoration and conservation of soil and water in the territory space.This manuscript analyzed and quantified the impact of EFPZ on the regional water conservation function,based on land use data from 2005,2008,2010,2015 and 2020,by conducting a counterfactual simulation along with the GeoSOS-FLUS model and the InVEST model.The results demonstrate that the delineation of EFPZ can significantly influence the water conservation.(1)From 2010 to 2020,as the EFPZ was implemented,the water conservation in the study area was increasing year by year,with a growth rate of 0.03×10^(8) m^(3)∙a^(-1).On the other hand,the simulated water conservation capacity without the implementation of EFPZ decreased year by year,with a decrease rate of 0.01×10^(8) m^(3)∙a^(-1).(2)The EFPZ accounts for only 23%of the total area,but the contribution rate of water conservation reaches 80%.The actual values of water conservation and average water yield per unit pixel in the EFPZ show an increasing trend both internally and externally,while the counterfactual simulation values exhibit a decreasing trend.(3)The water conservation is much higher within the EFPZ than without EFPZ.The implementation of EFPZ has a significant effect on the improvement of the water conservation capacity in Maqu EFPZ and Yellow River Source EFPZ.The protection effectiveness should be enhanced in Qilian Mountain EFPZ and afforestation activities need to be carefully considered in Loess Plateau EFPZ.展开更多
Wetlands offer important ecological functions and values.Wetland functional zoning provides a reference and basis for sustainable fulfilment and management.In this study,two coastal urban agglomerations in South China...Wetlands offer important ecological functions and values.Wetland functional zoning provides a reference and basis for sustainable fulfilment and management.In this study,two coastal urban agglomerations in South China were taken as study areas,namely,the Guangxi Beibu Gulf(GBG)and Guangdong-Hong Kong-Macao Greater Bay Area(GBA).Based on multisource information data,a wetland functional zoning system was constructed with the four levels of zoning concept,zoning principle,zoning basis,and zoning scheme.The functional zoning and dynamic analysis of wetlands from 1990 to 2020 were carried out from multiple perspectives of wetland ecological functions,wetland management and conservation functions.The results showed that:1)in terms of wetland ecological functions,the two coastal urban agglomerations were dominated by hydrological regulation and purification of environmental functional areas.The coastal region was largely characterized by the main functional areas of climate regulation and biodiversity maintenance.2)Regarding wetland management and conservation functions,two coastal urban agglomerations exhibited similar trends in terms of the sizes of their conservation and buffer zones from 1990 to 2020.Prevention and control zones were mainly located in core cities in a concentrated manner.Conservation zones largely comprised mountainous woodlands and important wetlands.3)The two coastal urban agglomerations could be divided into 21 wetland functional zones.The central river area has remained the main prevention and control zone for many years.Regarding conservation zones,ecological protection and restoration should be the main focus.Regarding buffer zones,the construction of wetlands and surrounding complex systems should be strengthened or enhanced.Regarding prevention and control zones,activities that do not affect wetland functions should be allowed,provided that they comply with existing laws and regulations.This study could provide technical support and practical application guidance for wetland regulation and management.展开更多
To adapt to national climate change strategies,understanding the thermal vulnerability of urban functional zones(UFZs)is critical for enhancing the livability and sustainable development of cities.We address the limit...To adapt to national climate change strategies,understanding the thermal vulnerability of urban functional zones(UFZs)is critical for enhancing the livability and sustainable development of cities.We address the limitations of existing thermal vulnerability assessments by incorporating human perception into the analysis.Specifically,we introduce the sky openness index to reflect human perception of the thermal environment and examine variations in thermal vulnerability across different UFZs.Using the Extreme Gradient Boosting(XGBoost)-SHapley Additive exPlanations(SHAP)model,we analyze the contributions of 2D and 3D urban form indicators to thermal vulnerability and link these contributions to the unique needs and vulnerability characteristics of UFZs of Foshan City,China in 2023.The results reveal that:1)high-value heat-fragile areas(1.74–2.00]constitute 10.42%of Foshan City;2)traffic zone and publiccommercial zone exhibit the highest levels of thermal vulnerability;and 3)building height and the normalized building index are the most influential factors,with contributions of|0.06|and|0.03|,respectively.We provide a scientific foundation for developing governance strategies to promote urban resilience.展开更多
Newest planning methods implemented by Chinese government are promoting a coordinated regional development and shaping an orderly spatial structure by applying the regulation of territorial function. This article anal...Newest planning methods implemented by Chinese government are promoting a coordinated regional development and shaping an orderly spatial structure by applying the regulation of territorial function. This article analyzes the problems of spatial planning and regional strategy caused by the wrongly-set primary goal of economic development; it states that the three-fold objective of competitiveness, sustainability, and welfare fairness shall be the principal for China to implement the spatial regulation in the new era; it discusses about theoretical thoughts and technology framework of conducting the ′Major Function Oriented Zone′ based on their different major functions that each region plays in urbanization and industrialization, ecological constructions, grain productions, and protection of natural and cultural heritages; it introduces the new concept of ′Major Function Oriented Zone′ that include the major functions category, the stereo regional equilibrium mode, the two-level zoning specification, and the territorial development intensity; it offers a zoning scheme that defines development-optimized and development-prioritized zones as regions with massive urbanization and industrialization, development-restricted zones as ecological constructing or grain producing regions, development-prohibited zones as natural and cultural heritage protecting regions; and finally it addresses the main obstacle for implementing ′Major Function Oriented Zone′, which is the institutional arrangement of the supreme goal of high GDP growth rate that is currently being implemented.展开更多
Research on the carbon budget and zoning for carbon compensation in major functional zones(MFZs)is important for formulating strategies for low-carbon development for each functional zone,promoting the collaborative g...Research on the carbon budget and zoning for carbon compensation in major functional zones(MFZs)is important for formulating strategies for low-carbon development for each functional zone,promoting the collaborative governance of the regional ecological environment,and achieving high-quality development.Such work can also contribute to achieving peak emissions and carbon neutrality.This paper constructs a theoretical framework for the carbon budget and carbon compensation from the perspective of the MFZ,uses 157 county-level units of the Beijing-Tianjin-Hebei urban agglomeration(BTHUA)as the study area,and introduces the concentration index,normalized revealed comparative advantage index,and Self Organizing Mapping-K-means(SOM-K-means)model to examine spatio-temporal variations in the carbon budget and carbon compensation zoning for the BTHUA from the perspective of MFZs.The authors propose a scheme for the spatial minimization of carbon emissions as oriented by low-carbon development.The results show that:(1)From 2000 to 2017,the carbon budget exhibited an upward trend of volatility,its centralization index was higher than the“warning line”of 0.4,and large regional differences in it were noted on the whole.(2)There were significant regional differences in the carbon budget,and carbon emissions exhibited a core-periphery spatial pattern,with a high-value center at Beijing-Tianjin-Tangshan that gradually decreased as it moved outward.However,the spatial pattern of carbon absorption tended to be stable,showing an inverted“U-shaped”pattern.It was high in the east,north,and west,and was low in the middle and the south.(3)The carbon budget was consistent with the strategic positioning of the MFZ,and the optimized development zone and key development zone were the main pressure-bearing areas for carbon emissions,while the key ecological functional zone was the dominant zone of carbon absorption.The difference in the centralization index of carbon absorption among the functional zones was smaller than that in the centralization index of carbon emissions.(4)There were 53 payment areas,64 balanced areas,and 40 obtaining areas in the study area.Nine types of carbon compensation zones were finally formed in light of the strategic objectives of the MFZ,and directions and strategies for low-carbon development are proposed for each type.(5)It is important to strengthen research on the carbon balance and horizontal carbon compensation at a microscopic scale,enrich the theoretical framework of regional carbon compensation,integrate it into the carbon trading market,and explore diversified paths for achieving peak emissions and carbon neutrality.展开更多
AIM:To investigate the size of functional optical zone(FOZ)after small incision lenticule extraction(SMILE)versus femtosecond laser assisted excimer laser keratomileusis(FS-LASIK)for myopia correction and potential as...AIM:To investigate the size of functional optical zone(FOZ)after small incision lenticule extraction(SMILE)versus femtosecond laser assisted excimer laser keratomileusis(FS-LASIK)for myopia correction and potential associated factors for FOZ.METHODS:A total of 133 patients who received corneal refractive surgery in our hospital between November 2018 and July 2021 were retrospectively enrolled.There were 63 patients(123 eyes)in SMILE group and 70patients(139 eyes)in FS-LASIK group.The size of FOZ was measured using Pentacam 3-dementional anterior segment analyzer before and 3mo after surgery,so as to analyze postoperative achieved functional optical zone(AFOZ)and its contributing parameters.RESULTS:When planned functional optical zone(PFOZ)was 6.5 mm for both groups,AFOZ was 1.45±0.27 and 1.67±0.25 mm smaller than preoperative FOZ in SMILE group and FS-LASIK group 3mo after surgery.AFOZ in SMILE group was significantly larger than that in FS-LASIK group(P<0.001).Variation of FOZ was negatively correlated with preoperative spherical equivalent(SE)and positively correlated with variation of mean keratometry value(△Km),variation of spherical aberration(△SA),and variation of Q-value(△Q,all P<0.001)in both groups.Multiple variable linear regression equations were△FOZ=1.354-0.1×pre-SE+0.336×△Q+1.462×△SA in SMILE group and△FOZ=1.512+0.137×△Q+0.468×△SA in FS-LASIK group.CONCLUSION:AFOZ is significantly smaller than preoperative FOZ in both SMILE and FS-LASIK groups.With the same PFOZ,larger AFOZ is achieved in SMILE group than in FS-LASIK group.展开更多
Ecological shelter zones reconstruction is an ecosystem restoration and conservation project aimed to the ecological safety of nations, regions and basins. Reconstruction of ecological shelter zones of the upper reach...Ecological shelter zones reconstruction is an ecosystem restoration and conservation project aimed to the ecological safety of nations, regions and basins. Reconstruction of ecological shelter zones of the upper reaches of the Yangtze River became one of the most important tasks of Western Development strategy. This article, taking Zhaotong as an example, studies the functional regionalization of ecological shelter zones. The study supplies a case for functional regionalization of small and medium regions whose main tasks are environment reservation. With the guidance of theories of functional regionalization, and based on the analysis of Zhaotong＇s natural, ecological and socioeconomic factors, the paper suggests five principles for factors selection. These principles include： （1） reversing order evaluation; （2） selecting main factors; （3） keeping the integrality of administrative regions of towns; and （4） making the products acceptable by local government. To analyze spatial status of selected factors, LUCC data in 2002, 1：50,000 relief maps and town-unit socioeconomic statistical data in 2004 are used. RS and GIS tools are also applied to melt traditional and modern geographical methods. This would be useful to functional regionalization research in mountainous areas. As a conclusion, the leading functional regions of ecological conservation or economic development are suggested, respectively. Zhaotong city is divided into two-level functional regions. The first-level includes three leading functional regions and they will lead developing direction of sub-regions. The second-level includes eight sub-regions, which are policy implemented regions, and will supply guidance to Zhaotong＇s ecological shelter zones reconstruction.展开更多
China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteri...China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China＇s MFOZs using a China＇ s Land Use Database （CLUD） derived from high-resolution remotely sensed images in the periods of 2000-2010 and 2010-2013. To sum up： （1） The percentage of built-up area in each of the MFOZs was significantly different, revealing the gradient feature of national land development based on the distribution of the main functions. （2） Annual growth in built-up area in optimal development zones （ODZs） decreased signifi- cantly during 2010-2013 compared with the period 2000-2010, while annual growth in built-up area in key development zones （KDZs）, agricultural production zones （APZs） and key ecological function zones （KEFZs） increased significantly. （3） In ODZs, the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions; the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions; average annual area growth of built-up area in APZs in the northeast, central and western regions was twice as high as the previous decade on average; the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region. （4） The spatial pattern and charac- teristics of built-up area expansions in the period 2010-2013 reflected the gradient feature of the plan for MFOZs. But the rate of increase locally in built-up area in ODZs, APZs and KEFZs is fast, so the effective measures must be adopted in the implementation of national and regional policies. The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.展开更多
The excessive expansion of urbanized areas has resulted in haphazard land utili- zation, immoderate consumption of superior agricultural land and water resources, significant fragmentation of agricultural landscape, a...The excessive expansion of urbanized areas has resulted in haphazard land utili- zation, immoderate consumption of superior agricultural land and water resources, significant fragmentation of agricultural landscape, and gradual deterioration of the agro-ecological en- vironment. Combined, these factors cause poor land use efficiency. Under these circum- stances, comprehensively assessing land use efficiency for urban agriculture is a key issue in land use research. Currently, evaluation methods for agricultural land use efficiency narrowly concentrate on aspects of economic input and output. However, urban agro-ecosystems can provide diverse economic, social, and ecological services and functions. In particular, the social and ecological services and functions originating from agricultural land, which have a higher value than economic services, play a significant role in ensuring regional social, eco- logical, and environmental security. However, recent research has rarely taken these benefits into consideration. Therefore, land use value has been greatly underestimated, which has resulted in mishandled and poor land use policies. In this study, we apply Landsat imagery and social and economic statistical data for the Xi＇an metropolitan zone （XMZ） to investigate agricultural multi-functionality. We develop an evaluation framework for urban agricultural land use efficiency and identify agro-ecosystem services and functions as important outputs from agricultural land. The land use efficiency of urban agriculture is then evaluated using ecosystem services models, providing a mechanism for assessing spatial-temporal changes in land use efficiency in the XMZ from 1999 to 2015. Four important conclusions are reached from this analysis. First, the rapid urbanization and agricultural transformation from traditional cereal cultivation to modern urban agriculture has resulted in steadily increasing costs, out- puts, and land use efficiency of urban agriculture. The total output value increased 41% and land use efficiency per hectare increased by 33.13% on average. Second, the spatial patterns of comprehensive output and land use efficiency were dominated by economic outputs from agricultural land. Areas near cities, which are dominated by orchard and arable land, provide more economic functions. These areas support and regulate services due to the transforma- tion from extensive cereal production to intensive modern urban agriculture; therefore, they have higher output value and land use efficiency. In contrast, areas distant from cities, towns, and high traffic roads, namely, remote rural areas, provide more support and regulating ser- vices, but have relatively lower economic function due to inaccessibility tO urban markets and slow agricultural transformation. Therefore, these areas have lower output value and land use efficiency. The spatial change in agricultural output and land use efficiency in urban areas is strongly dependent on the degree of urbanization and agricultural transformation. Third, the total output value and land use efficiency of urban agriculture measured with our approach are much higher than evaluations using traditional methods. However, the spatial patterns measured using the two approaches are in agreement. The evaluation framework integrates ecological services and economic and social functions into a comprehensive output from agricultural land. This approach is more methodical and accurate for evaluating the compre- hensive efficiency of land use based on quantities and spatial scale because they are at the pixel scale. Finally, the evaluation results have important implications for enhancing current agricultural subsidies and even implementing ecological payment policies in China. Most importantly, they can be directly applied to agricultural transformation regulations, decision-making, and guidance for rational land utilization.展开更多
Sensitive smell discrimination is based on structural plasticity of the olfactory bulb,which depends on migration and integration of newborn neurons from the subventricular zone.In this study,we examined the relations...Sensitive smell discrimination is based on structural plasticity of the olfactory bulb,which depends on migration and integration of newborn neurons from the subventricular zone.In this study,we examined the relationship between neural stem cell status in the subventricular zone and olfactory function in rats with diabetes mellitus.Streptozotocin was injected through the femoral vein to induce type 1 diabetes mellitus in Sprague-Dawley rats.Two months after injection,olfactory sensitivity was decreased in diabetic rats.Meanwhile,the number of Brd U-positive and Brd U＋/DCX＋double-labeled cells was lower in the subventricular zone of diabetic rats compared with agematched normal rats.Western blot results revealed downregulated expression of insulin receptorβ,phosphorylated glycogen synthase kinase 3β,and β-catenin in the subventricular zone of diabetic rats.Altogether,these results indicate that diabetes mellitus causes insulin deficiency,which negatively regulates glycogen synthase kinase 3β and enhances β-catenin degradation,with these changes inhibiting neural stem cell proliferation.Further,these signaling pathways affect proliferation and differentiation of neural stem cells in the subventricular zone.Dysfunction of subventricular zone neural stem cells causes a decline in olfactory bulb structural plasticity and impairs olfactory sensitivity in diabetic rats.展开更多
To solve some unreasonable problems in the acceptance process of the delimitation project of grain production functional zones,the acceptance results of grain production functional zones in Fangzi District,Weifang Cit...To solve some unreasonable problems in the acceptance process of the delimitation project of grain production functional zones,the acceptance results of grain production functional zones in Fangzi District,Weifang City were elaborated from the aspects of the third party organization,inspectors,expert group,acceptance criteria,acceptance method,acceptance contents,etc.,and the overall performance of the project was reviewed.The problems that need to be rectified during the implementation of the project were put forward,and the irrationality of the acceptance and the places that need to be improved were pointed out,which would provide a better guiding value for the delimitation of grain production functional zone and the acceptance and performance evaluation of similar projects.展开更多
Teleseismic events recorded by stations located in the Adamawa Plateau have been treated using the inversion method of receiver functions. These six stations are part of a network of 32 large strip seismic stations in...Teleseismic events recorded by stations located in the Adamawa Plateau have been treated using the inversion method of receiver functions. These six stations are part of a network of 32 large strip seismic stations installed in Cameroon between 2005 and 2007. This method allowed us to investigate the lithospheric mantle in that region. The results obtained from the velocity model have been compared to some existing results in this region. These results show the existence of a thick crust having an average thickness of about 35.2 km and a corresponding S wave velocity of 3.7 km/s. For an average S wave velocity of 4.4 km/s the lithospheric mantle appears to be thin in nature and has a thickness that varies from 39 km and 49.6 km. Beyond the lower lithospheric mantle, there exists a low velocity zone, whose thickness varies between 20 km and 43.9 km. The variation of the low velocity zone leads to variation of the lower boundary of the lithospheric mantle boundary at the depths ranging from 73.8 km and 85 km.展开更多
基金National Basic Research Program of China,No.2015CB953603National Natural Science Foundation of China,No.41671339State Key Laboratory of Earth Surface Processes and Resource Ecology,No.2017-FX-01(1)
文摘Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for the IS in Beijing metropolitan region. However, most previous studies primarily considered the Beijing metropolitan region as a whole without considering the differences and heterogeneity among the function zones. In this study, the subpixel impervious surface results in Beijing within a time series(1991, 2001, 2005, 2011 and 2015) were extracted by means of the classification and regression tree(CART) model combined with change detection models. Then based on the method of standard deviation ellipse, Lorenz curve, contribution index(CI) and landscape metrics, the spatio-temporal dynamics and variations of IS(1991, 2001, 2011 and 2015) in different function zones and districts were analyzed. It is found that the total area of impervious surface in Beijing increased dramatically during the study period, increasing about 144.18%. The deflection angle of major axis of standard deviation ellipse decreased from 47.15° to 38.82°, indicating the major development axis in Beijing gradually moved from northeast-southwest to north-south. Moreover, the heterogeneity of impervious surface’s distribution among 16 districts weakened gradually, but the CI values and landscape metrics in four function zones differed greatly. The urban function extended zone(UFEZ), the main source of the growth of IS in Beijing, had the highest CI values. Its lowest CI value was 1.79 that is still much higher than the highest CI value in other function zones. The core function zone(CFZ), the traditional aggregation zone of impervious surface, had the highest contagion index(CONTAG) values, but it contributed less than UFEZ due to its small area. The CI value of the new urban developed zone(NUDZ) increased rapidly, and it increased from negative to positive and multiplied, becoming animportant contributor to the rise of urban impervious surface. However, the ecological conservation zone(ECZ) had a constant negative contribution all the time, and its CI value decreased gradually. Moreover, the landscape metrics and centroids of impervious surface in different density classes differed greatly. The high-density impervious surface had a more compact configuration and a greater impact on the eco-environment.
基金Major Program of National Natural Science Foundation of China,No.41590841Key Project for National Natural Science Foundation of China,No.41230633
文摘Urbanization significantly increases the risk of urban flooding. Therefore, quantitative study of urban rainfall-runoff processes can provide a scientific basis for urban planning and management. In this paper, the built-up region within the Fifth Ring Road of Beijing was selected as the study area. The details of land cover and urban function zones(UFZs) were identified using GIS and RS methods. On this basis, the SCS-CN model was adopted to analyze the rainfall-runoff risk characteristics of the study area. The results showed that:(1) UFZs within different levels of runoff risk varied under different rainfall conditions. The area ratio of the UFZs with high runoff risk increased from 18.90%(for rainfall return period of 1 a) to 54.74%(for period of 100 a). Specifically, urban commercial areas tended to have the highest runoff risk, while urban greening spaces had the lowest.(2) The spatial characteristics of the runoff risks showed an obvious circular distribution. Spatial cluster areas with high runoff risk were mainly concentrated in the center of the study area, while those with low runoff risk were mainly distributed between the fourth and fifth ring roads. The results indicated that the spatial clustering characteristic of urban runoff risk and runoff heterogeneity among different UFZs should be fully considered during urban rainwater management.
基金funded by the National Science Foundation of China(Grant No.42161043)the improvement plan of scientific research ability in Northwest Normal University(NWNU-LKQN2020-16).
文摘The implementation of Ecological Function Protection Zone(EFPZ)policy is significant for the ecological restoration and conservation of soil and water in the territory space.This manuscript analyzed and quantified the impact of EFPZ on the regional water conservation function,based on land use data from 2005,2008,2010,2015 and 2020,by conducting a counterfactual simulation along with the GeoSOS-FLUS model and the InVEST model.The results demonstrate that the delineation of EFPZ can significantly influence the water conservation.(1)From 2010 to 2020,as the EFPZ was implemented,the water conservation in the study area was increasing year by year,with a growth rate of 0.03×10^(8) m^(3)∙a^(-1).On the other hand,the simulated water conservation capacity without the implementation of EFPZ decreased year by year,with a decrease rate of 0.01×10^(8) m^(3)∙a^(-1).(2)The EFPZ accounts for only 23%of the total area,but the contribution rate of water conservation reaches 80%.The actual values of water conservation and average water yield per unit pixel in the EFPZ show an increasing trend both internally and externally,while the counterfactual simulation values exhibit a decreasing trend.(3)The water conservation is much higher within the EFPZ than without EFPZ.The implementation of EFPZ has a significant effect on the improvement of the water conservation capacity in Maqu EFPZ and Yellow River Source EFPZ.The protection effectiveness should be enhanced in Qilian Mountain EFPZ and afforestation activities need to be carefully considered in Loess Plateau EFPZ.
基金Under the auspices of National Natural Science Foundation of China(No.U21A2022,U1901219,42101369)National Key Research and Development Program of China(No.2023YFF0807204)。
文摘Wetlands offer important ecological functions and values.Wetland functional zoning provides a reference and basis for sustainable fulfilment and management.In this study,two coastal urban agglomerations in South China were taken as study areas,namely,the Guangxi Beibu Gulf(GBG)and Guangdong-Hong Kong-Macao Greater Bay Area(GBA).Based on multisource information data,a wetland functional zoning system was constructed with the four levels of zoning concept,zoning principle,zoning basis,and zoning scheme.The functional zoning and dynamic analysis of wetlands from 1990 to 2020 were carried out from multiple perspectives of wetland ecological functions,wetland management and conservation functions.The results showed that:1)in terms of wetland ecological functions,the two coastal urban agglomerations were dominated by hydrological regulation and purification of environmental functional areas.The coastal region was largely characterized by the main functional areas of climate regulation and biodiversity maintenance.2)Regarding wetland management and conservation functions,two coastal urban agglomerations exhibited similar trends in terms of the sizes of their conservation and buffer zones from 1990 to 2020.Prevention and control zones were mainly located in core cities in a concentrated manner.Conservation zones largely comprised mountainous woodlands and important wetlands.3)The two coastal urban agglomerations could be divided into 21 wetland functional zones.The central river area has remained the main prevention and control zone for many years.Regarding conservation zones,ecological protection and restoration should be the main focus.Regarding buffer zones,the construction of wetlands and surrounding complex systems should be strengthened or enhanced.Regarding prevention and control zones,activities that do not affect wetland functions should be allowed,provided that they comply with existing laws and regulations.This study could provide technical support and practical application guidance for wetland regulation and management.
基金Under the auspices of Liaoning Revitalization Talents Program(No.XLYC2202024)Basic Scientific Research Project(Key Project)of the Education Department of Liaoning Province(No.LJ212410165084)the Fundamental Research Funds for the Central Universities(No.N2111003,N2411001)。
文摘To adapt to national climate change strategies,understanding the thermal vulnerability of urban functional zones(UFZs)is critical for enhancing the livability and sustainable development of cities.We address the limitations of existing thermal vulnerability assessments by incorporating human perception into the analysis.Specifically,we introduce the sky openness index to reflect human perception of the thermal environment and examine variations in thermal vulnerability across different UFZs.Using the Extreme Gradient Boosting(XGBoost)-SHapley Additive exPlanations(SHAP)model,we analyze the contributions of 2D and 3D urban form indicators to thermal vulnerability and link these contributions to the unique needs and vulnerability characteristics of UFZs of Foshan City,China in 2023.The results reveal that:1)high-value heat-fragile areas(1.74–2.00]constitute 10.42%of Foshan City;2)traffic zone and publiccommercial zone exhibit the highest levels of thermal vulnerability;and 3)building height and the normalized building index are the most influential factors,with contributions of|0.06|and|0.03|,respectively.We provide a scientific foundation for developing governance strategies to promote urban resilience.
基金Under the auspices of Key Project of National Natural Science Foundation of China (No. 40830741)National Key Technology R&D Program (No. 2008BAH31B01)
文摘Newest planning methods implemented by Chinese government are promoting a coordinated regional development and shaping an orderly spatial structure by applying the regulation of territorial function. This article analyzes the problems of spatial planning and regional strategy caused by the wrongly-set primary goal of economic development; it states that the three-fold objective of competitiveness, sustainability, and welfare fairness shall be the principal for China to implement the spatial regulation in the new era; it discusses about theoretical thoughts and technology framework of conducting the ′Major Function Oriented Zone′ based on their different major functions that each region plays in urbanization and industrialization, ecological constructions, grain productions, and protection of natural and cultural heritages; it introduces the new concept of ′Major Function Oriented Zone′ that include the major functions category, the stereo regional equilibrium mode, the two-level zoning specification, and the territorial development intensity; it offers a zoning scheme that defines development-optimized and development-prioritized zones as regions with massive urbanization and industrialization, development-restricted zones as ecological constructing or grain producing regions, development-prohibited zones as natural and cultural heritage protecting regions; and finally it addresses the main obstacle for implementing ′Major Function Oriented Zone′, which is the institutional arrangement of the supreme goal of high GDP growth rate that is currently being implemented.
基金National Natural Science Foundation of China(42121001)National Natural Science Foundation of China(42130712)+1 种基金National Natural Science Foundation of China(42022007)Youth Innovation Promotion Association,CAS(2018069)。
文摘Research on the carbon budget and zoning for carbon compensation in major functional zones(MFZs)is important for formulating strategies for low-carbon development for each functional zone,promoting the collaborative governance of the regional ecological environment,and achieving high-quality development.Such work can also contribute to achieving peak emissions and carbon neutrality.This paper constructs a theoretical framework for the carbon budget and carbon compensation from the perspective of the MFZ,uses 157 county-level units of the Beijing-Tianjin-Hebei urban agglomeration(BTHUA)as the study area,and introduces the concentration index,normalized revealed comparative advantage index,and Self Organizing Mapping-K-means(SOM-K-means)model to examine spatio-temporal variations in the carbon budget and carbon compensation zoning for the BTHUA from the perspective of MFZs.The authors propose a scheme for the spatial minimization of carbon emissions as oriented by low-carbon development.The results show that:(1)From 2000 to 2017,the carbon budget exhibited an upward trend of volatility,its centralization index was higher than the“warning line”of 0.4,and large regional differences in it were noted on the whole.(2)There were significant regional differences in the carbon budget,and carbon emissions exhibited a core-periphery spatial pattern,with a high-value center at Beijing-Tianjin-Tangshan that gradually decreased as it moved outward.However,the spatial pattern of carbon absorption tended to be stable,showing an inverted“U-shaped”pattern.It was high in the east,north,and west,and was low in the middle and the south.(3)The carbon budget was consistent with the strategic positioning of the MFZ,and the optimized development zone and key development zone were the main pressure-bearing areas for carbon emissions,while the key ecological functional zone was the dominant zone of carbon absorption.The difference in the centralization index of carbon absorption among the functional zones was smaller than that in the centralization index of carbon emissions.(4)There were 53 payment areas,64 balanced areas,and 40 obtaining areas in the study area.Nine types of carbon compensation zones were finally formed in light of the strategic objectives of the MFZ,and directions and strategies for low-carbon development are proposed for each type.(5)It is important to strengthen research on the carbon balance and horizontal carbon compensation at a microscopic scale,enrich the theoretical framework of regional carbon compensation,integrate it into the carbon trading market,and explore diversified paths for achieving peak emissions and carbon neutrality.
基金Supported by Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2022L201)。
文摘AIM:To investigate the size of functional optical zone(FOZ)after small incision lenticule extraction(SMILE)versus femtosecond laser assisted excimer laser keratomileusis(FS-LASIK)for myopia correction and potential associated factors for FOZ.METHODS:A total of 133 patients who received corneal refractive surgery in our hospital between November 2018 and July 2021 were retrospectively enrolled.There were 63 patients(123 eyes)in SMILE group and 70patients(139 eyes)in FS-LASIK group.The size of FOZ was measured using Pentacam 3-dementional anterior segment analyzer before and 3mo after surgery,so as to analyze postoperative achieved functional optical zone(AFOZ)and its contributing parameters.RESULTS:When planned functional optical zone(PFOZ)was 6.5 mm for both groups,AFOZ was 1.45±0.27 and 1.67±0.25 mm smaller than preoperative FOZ in SMILE group and FS-LASIK group 3mo after surgery.AFOZ in SMILE group was significantly larger than that in FS-LASIK group(P<0.001).Variation of FOZ was negatively correlated with preoperative spherical equivalent(SE)and positively correlated with variation of mean keratometry value(△Km),variation of spherical aberration(△SA),and variation of Q-value(△Q,all P<0.001)in both groups.Multiple variable linear regression equations were△FOZ=1.354-0.1×pre-SE+0.336×△Q+1.462×△SA in SMILE group and△FOZ=1.512+0.137×△Q+0.468×△SA in FS-LASIK group.CONCLUSION:AFOZ is significantly smaller than preoperative FOZ in both SMILE and FS-LASIK groups.With the same PFOZ,larger AFOZ is achieved in SMILE group than in FS-LASIK group.
基金National Natural＇Science Foundation of China, No.40401016
文摘Ecological shelter zones reconstruction is an ecosystem restoration and conservation project aimed to the ecological safety of nations, regions and basins. Reconstruction of ecological shelter zones of the upper reaches of the Yangtze River became one of the most important tasks of Western Development strategy. This article, taking Zhaotong as an example, studies the functional regionalization of ecological shelter zones. The study supplies a case for functional regionalization of small and medium regions whose main tasks are environment reservation. With the guidance of theories of functional regionalization, and based on the analysis of Zhaotong＇s natural, ecological and socioeconomic factors, the paper suggests five principles for factors selection. These principles include： （1） reversing order evaluation; （2） selecting main factors; （3） keeping the integrality of administrative regions of towns; and （4） making the products acceptable by local government. To analyze spatial status of selected factors, LUCC data in 2002, 1：50,000 relief maps and town-unit socioeconomic statistical data in 2004 are used. RS and GIS tools are also applied to melt traditional and modern geographical methods. This would be useful to functional regionalization research in mountainous areas. As a conclusion, the leading functional regions of ecological conservation or economic development are suggested, respectively. Zhaotong city is divided into two-level functional regions. The first-level includes three leading functional regions and they will lead developing direction of sub-regions. The second-level includes eight sub-regions, which are policy implemented regions, and will supply guidance to Zhaotong＇s ecological shelter zones reconstruction.
基金Key Project of National Natural Science Foundation of China, No.41371409 National Key Technology R＆D Program, No.2013BAC03B00
文摘China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China＇s MFOZs using a China＇ s Land Use Database （CLUD） derived from high-resolution remotely sensed images in the periods of 2000-2010 and 2010-2013. To sum up： （1） The percentage of built-up area in each of the MFOZs was significantly different, revealing the gradient feature of national land development based on the distribution of the main functions. （2） Annual growth in built-up area in optimal development zones （ODZs） decreased signifi- cantly during 2010-2013 compared with the period 2000-2010, while annual growth in built-up area in key development zones （KDZs）, agricultural production zones （APZs） and key ecological function zones （KEFZs） increased significantly. （3） In ODZs, the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions; the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions; average annual area growth of built-up area in APZs in the northeast, central and western regions was twice as high as the previous decade on average; the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region. （4） The spatial pattern and charac- teristics of built-up area expansions in the period 2010-2013 reflected the gradient feature of the plan for MFOZs. But the rate of increase locally in built-up area in ODZs, APZs and KEFZs is fast, so the effective measures must be adopted in the implementation of national and regional policies. The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.
基金National Natural Science Foundation of China, No.41271550 Humanities and Social Sciences Project of Ministry of Education in the West and the Frontier Areas, No. 12XJC790003
文摘The excessive expansion of urbanized areas has resulted in haphazard land utili- zation, immoderate consumption of superior agricultural land and water resources, significant fragmentation of agricultural landscape, and gradual deterioration of the agro-ecological en- vironment. Combined, these factors cause poor land use efficiency. Under these circum- stances, comprehensively assessing land use efficiency for urban agriculture is a key issue in land use research. Currently, evaluation methods for agricultural land use efficiency narrowly concentrate on aspects of economic input and output. However, urban agro-ecosystems can provide diverse economic, social, and ecological services and functions. In particular, the social and ecological services and functions originating from agricultural land, which have a higher value than economic services, play a significant role in ensuring regional social, eco- logical, and environmental security. However, recent research has rarely taken these benefits into consideration. Therefore, land use value has been greatly underestimated, which has resulted in mishandled and poor land use policies. In this study, we apply Landsat imagery and social and economic statistical data for the Xi＇an metropolitan zone （XMZ） to investigate agricultural multi-functionality. We develop an evaluation framework for urban agricultural land use efficiency and identify agro-ecosystem services and functions as important outputs from agricultural land. The land use efficiency of urban agriculture is then evaluated using ecosystem services models, providing a mechanism for assessing spatial-temporal changes in land use efficiency in the XMZ from 1999 to 2015. Four important conclusions are reached from this analysis. First, the rapid urbanization and agricultural transformation from traditional cereal cultivation to modern urban agriculture has resulted in steadily increasing costs, out- puts, and land use efficiency of urban agriculture. The total output value increased 41% and land use efficiency per hectare increased by 33.13% on average. Second, the spatial patterns of comprehensive output and land use efficiency were dominated by economic outputs from agricultural land. Areas near cities, which are dominated by orchard and arable land, provide more economic functions. These areas support and regulate services due to the transforma- tion from extensive cereal production to intensive modern urban agriculture; therefore, they have higher output value and land use efficiency. In contrast, areas distant from cities, towns, and high traffic roads, namely, remote rural areas, provide more support and regulating ser- vices, but have relatively lower economic function due to inaccessibility tO urban markets and slow agricultural transformation. Therefore, these areas have lower output value and land use efficiency. The spatial change in agricultural output and land use efficiency in urban areas is strongly dependent on the degree of urbanization and agricultural transformation. Third, the total output value and land use efficiency of urban agriculture measured with our approach are much higher than evaluations using traditional methods. However, the spatial patterns measured using the two approaches are in agreement. The evaluation framework integrates ecological services and economic and social functions into a comprehensive output from agricultural land. This approach is more methodical and accurate for evaluating the compre- hensive efficiency of land use based on quantities and spatial scale because they are at the pixel scale. Finally, the evaluation results have important implications for enhancing current agricultural subsidies and even implementing ecological payment policies in China. Most importantly, they can be directly applied to agricultural transformation regulations, decision-making, and guidance for rational land utilization.
基金partly supported by the National Natural Science Foundation of China,No.81370448,81570725
文摘Sensitive smell discrimination is based on structural plasticity of the olfactory bulb,which depends on migration and integration of newborn neurons from the subventricular zone.In this study,we examined the relationship between neural stem cell status in the subventricular zone and olfactory function in rats with diabetes mellitus.Streptozotocin was injected through the femoral vein to induce type 1 diabetes mellitus in Sprague-Dawley rats.Two months after injection,olfactory sensitivity was decreased in diabetic rats.Meanwhile,the number of Brd U-positive and Brd U＋/DCX＋double-labeled cells was lower in the subventricular zone of diabetic rats compared with agematched normal rats.Western blot results revealed downregulated expression of insulin receptorβ,phosphorylated glycogen synthase kinase 3β,and β-catenin in the subventricular zone of diabetic rats.Altogether,these results indicate that diabetes mellitus causes insulin deficiency,which negatively regulates glycogen synthase kinase 3β and enhances β-catenin degradation,with these changes inhibiting neural stem cell proliferation.Further,these signaling pathways affect proliferation and differentiation of neural stem cells in the subventricular zone.Dysfunction of subventricular zone neural stem cells causes a decline in olfactory bulb structural plasticity and impairs olfactory sensitivity in diabetic rats.
文摘To solve some unreasonable problems in the acceptance process of the delimitation project of grain production functional zones,the acceptance results of grain production functional zones in Fangzi District,Weifang City were elaborated from the aspects of the third party organization,inspectors,expert group,acceptance criteria,acceptance method,acceptance contents,etc.,and the overall performance of the project was reviewed.The problems that need to be rectified during the implementation of the project were put forward,and the irrationality of the acceptance and the places that need to be improved were pointed out,which would provide a better guiding value for the delimitation of grain production functional zone and the acceptance and performance evaluation of similar projects.
文摘Teleseismic events recorded by stations located in the Adamawa Plateau have been treated using the inversion method of receiver functions. These six stations are part of a network of 32 large strip seismic stations installed in Cameroon between 2005 and 2007. This method allowed us to investigate the lithospheric mantle in that region. The results obtained from the velocity model have been compared to some existing results in this region. These results show the existence of a thick crust having an average thickness of about 35.2 km and a corresponding S wave velocity of 3.7 km/s. For an average S wave velocity of 4.4 km/s the lithospheric mantle appears to be thin in nature and has a thickness that varies from 39 km and 49.6 km. Beyond the lower lithospheric mantle, there exists a low velocity zone, whose thickness varies between 20 km and 43.9 km. The variation of the low velocity zone leads to variation of the lower boundary of the lithospheric mantle boundary at the depths ranging from 73.8 km and 85 km.
