The‘human-land relationship’has long been a central topic in geography,ecology,and social sciences.And dynamic monit-oring of the land use/cover change(LUCC)and landscape pattern studies of land use provide essentia...The‘human-land relationship’has long been a central topic in geography,ecology,and social sciences.And dynamic monit-oring of the land use/cover change(LUCC)and landscape pattern studies of land use provide essential theoretical support for this field.On the basis of physicogeographical regionalization and landscape ecology theory,this study proposed a method for characterizing land-scape pattern by using the minmium natural complex as the basic evaluation unit,constructing a four-level classification framework that included natural area,landscape region,landscape subregion,and landscape group.The method was tested in the Songhua River Basin,China,and the results revealed that:(1)the landscape pattern characterization in the Songhua River Basin validated the feasibility of the proposed method,and the use of the minimum natural complex as the basic measurement unit for landscape pattern characterization be-nefited research in this field.(2)The multiscale landscape pattern characterization system,which was framed around natural area,land-scape region,landscape subregion,and landscape group,accurately reflected the spatial heterogeneity of the physical geographic envir-onment and the impact of human activities on the landscape pattern in the Songhua River Basin.The nature-dominated landscape region was mainly concentrated in high-altitude mountainous and hilly areas,the human-dominated landscape region was located on plains and platforms,and the human-land interaction landscape region exhibited a landscape pattern that is closely related to natural factors such as temperature,precipitation,and soil.(3)The proposed method not only revealed the complex interactions between the physical geograph-ic environment and human activities but also provided scientific support for land use planning and ecological environment management.Future research should incorporate higher-resolution data and socioeconomic factors to further explore the dynamic changes in land-scape patterns and their impacts on the regional ecological environment.展开更多
Dear Editor,The brain experiences ongoing changes across different ages to support brain development and functional reorganization.During the span of adulthood,although the brain has matured from a neurobiological per...Dear Editor,The brain experiences ongoing changes across different ages to support brain development and functional reorganization.During the span of adulthood,although the brain has matured from a neurobiological perspective,it is still continuously shaped by external factors such as habits,the family setting,socioeconomic status,and the work environment [1].In contrast to chronological age (CA),brain(or biological) age (BA) is conceptualized as an important index for characterizing the aging process and neuropsychological state,as well as individual cognitiveperformance.Growing evidence indicates that BA can be assessed by neuroimaging techniques,including MRI [2].展开更多
Pressure buildup testing can be used to analyze fracture network characteristics and conduct quantitative interpretation of relevant parameters for shale gas wells,thus providing bases for assessing the well productiv...Pressure buildup testing can be used to analyze fracture network characteristics and conduct quantitative interpretation of relevant parameters for shale gas wells,thus providing bases for assessing the well productivity and formulating proper development strategies.This study establishes a new well test interpretation model for fractured horizontal wells based on seepage mechanisms of shale reservoirs and proposes a method for identifying fracturing patterns based on the characteristic slopes of pressure buildup curves and curve combination patterns.The pressure buildup curve patterns are identified to represent three types of shale reservoirs in the Sichuan Basin,namely the moderately deep shale reservoirs with high pressure,deep shale reservoirs with ultra-high pressure,and moderately deep shale reservoirs with normal pressure.Based on this,the relationship between the typical pressure buildup curve patterns and the fracture network types are put forward.Fracturing effects of three types of shale gas reservoir are compared and analyzed.The results show that typical flow patterns of shale reservoirs include bilinear flow in primary and secondary fractures,linear flow in secondary fractures,bilinear flow in secondary fractures and matrix,and linear flow in matrix.The fracture network characteristics can be determined using the characteristic slopes of pressure buildup curves and curve combinations.The linear flow in early secondary fractures is increasingly distinct with an increase in primary fracture conductivity.Moreover,the bilinear flow in secondary fractures and matrix and the subsequent linear flow in the matrix occur as the propping and density of secondary fractures increase.The increase in the burial depth,in-situ stress,and stress difference corresponds to a decrease in the propping of primary fractures that expand along different directions in the shale gas wells in the Sichuan Basin.Four pressure buildup curve patterns exist in the Sichuan Basin and its periphery.The pattern of pressure buildup curves of shale reservoirs in the Yongchuan area can be described as 1/2/→1/4,indicating limited stimulated reservoir volume,poorly propped secondary fractures,and the forming of primary fractures that extend only to certain directions.The pressure buildup curves of shale reservoirs in the main block of the Fuling area show a pattern of 1/4/→1/2 or 1/2,indicating greater stimulated reservoir volume,well propped secondary fractures,and the forming of complex fracture networks.The pattern of pressure buildup curves of shale reservoirs in the Pingqiao area is 1/2/→1/4→/1/2,indicating a fracturing effect somewhere between that of the Fuling and Yongchuan areas.For reservoirs with normal pressure,it is difficult to determine fracture network characteristics from pressure buildup curves due to insufficient formation energy and limited liquid drainage.展开更多
One important MN-puzzle problem is to find a sequence of up-down and right-left movements of the empty-cell so that a goal-pattern can be achieved from a given initial-pattern.The second problem is to characterize the...One important MN-puzzle problem is to find a sequence of up-down and right-left movements of the empty-cell so that a goal-pattern can be achieved from a given initial-pattern.The second problem is to characterize the totality of the goal-pattern from a given initial-pattern.The third problem is finding the fewest movements to achieve it.In this paper,these problems will be completely solved.展开更多
Introduction:Leptospirosis has historically been a severe public health concern across multiple Chinese provinces.Despite an overall decline in incidence in recent years,the disease continues to exhibit fluctuations a...Introduction:Leptospirosis has historically been a severe public health concern across multiple Chinese provinces.Despite an overall decline in incidence in recent years,the disease continues to exhibit fluctuations and occasionally triggers localized outbreaks.This study aimed to characterize the demographic and spatiotemporal patterns of leptospirosis in Anhui Province—a historically significant epidemic region—from 2004 to 2023,to investigate potential climatic and environmental risk factors,and to identify critical targets for disease prevention and control.Methods:Spatiotemporal cluster analysis was conducted using SaTScan software.Spearman correlation analysis was performed using SPSS to examine the short-term lagged effects of rainfall,temperature,and normalized difference vegetation index(NDVI)on leptospirosis incidence in the highrisk counties of Huaiyuan and Jingde.Results:A total of 458 leptospirosis cases were reported across Anhui Province during the 20-year study period.Middle-aged individuals(40–59 years),males,and agricultural workers constituted the primary high-risk populations.Spatiotemporal scanning identified nine adjacent hotspots in southern Anhui during 2004–2012,with a subsequent shift to Huaiyuan County in the northern Huaihe River Basin during 2016–2021.Significant associations were observed between leptospirosis cases and temperature,rainfall,and NDVI in both Huaiyuan and Jingde counties.Conclusion:This study revealed significant spatial heterogeneity,distinct spatiotemporal clustering patterns,and potential climatic and environmental risk factors for leptospirosis in Anhui Province during 2004–2023.These findings provide critical information regarding target regions,high-risk populations,and climatic and environmental factors to inform early warning systems and enhance prevention and control strategies for leptospirosis.展开更多
基金Under the auspices of Strategic Priority Research Program(A)of the Chinese Academy of Sciences(No.XDA28080503)National Natural Science Foundation of China(No.42071025)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2023240)。
文摘The‘human-land relationship’has long been a central topic in geography,ecology,and social sciences.And dynamic monit-oring of the land use/cover change(LUCC)and landscape pattern studies of land use provide essential theoretical support for this field.On the basis of physicogeographical regionalization and landscape ecology theory,this study proposed a method for characterizing land-scape pattern by using the minmium natural complex as the basic evaluation unit,constructing a four-level classification framework that included natural area,landscape region,landscape subregion,and landscape group.The method was tested in the Songhua River Basin,China,and the results revealed that:(1)the landscape pattern characterization in the Songhua River Basin validated the feasibility of the proposed method,and the use of the minimum natural complex as the basic measurement unit for landscape pattern characterization be-nefited research in this field.(2)The multiscale landscape pattern characterization system,which was framed around natural area,land-scape region,landscape subregion,and landscape group,accurately reflected the spatial heterogeneity of the physical geographic envir-onment and the impact of human activities on the landscape pattern in the Songhua River Basin.The nature-dominated landscape region was mainly concentrated in high-altitude mountainous and hilly areas,the human-dominated landscape region was located on plains and platforms,and the human-land interaction landscape region exhibited a landscape pattern that is closely related to natural factors such as temperature,precipitation,and soil.(3)The proposed method not only revealed the complex interactions between the physical geograph-ic environment and human activities but also provided scientific support for land use planning and ecological environment management.Future research should incorporate higher-resolution data and socioeconomic factors to further explore the dynamic changes in land-scape patterns and their impacts on the regional ecological environment.
基金supported by the National Natural Science Foundation of China(61971420)the Beijing Brain Initiative of the Beijing Municipal Science and Technology Commission(Z181100001518003)+1 种基金Special Projects of Brain Science of the Beijing Municipal Science and Technology Commission(Z161100000216139 and Z171100000117002)the International Cooperation and Exchange of the National Natural Science Foundation of China(31620103905)。
文摘Dear Editor,The brain experiences ongoing changes across different ages to support brain development and functional reorganization.During the span of adulthood,although the brain has matured from a neurobiological perspective,it is still continuously shaped by external factors such as habits,the family setting,socioeconomic status,and the work environment [1].In contrast to chronological age (CA),brain(or biological) age (BA) is conceptualized as an important index for characterizing the aging process and neuropsychological state,as well as individual cognitiveperformance.Growing evidence indicates that BA can be assessed by neuroimaging techniques,including MRI [2].
基金SINOPEC's Scientific and Technological Research Project:Research on effective production strategies of Jurassic continental shale oil and gas(No.P21078-5).
文摘Pressure buildup testing can be used to analyze fracture network characteristics and conduct quantitative interpretation of relevant parameters for shale gas wells,thus providing bases for assessing the well productivity and formulating proper development strategies.This study establishes a new well test interpretation model for fractured horizontal wells based on seepage mechanisms of shale reservoirs and proposes a method for identifying fracturing patterns based on the characteristic slopes of pressure buildup curves and curve combination patterns.The pressure buildup curve patterns are identified to represent three types of shale reservoirs in the Sichuan Basin,namely the moderately deep shale reservoirs with high pressure,deep shale reservoirs with ultra-high pressure,and moderately deep shale reservoirs with normal pressure.Based on this,the relationship between the typical pressure buildup curve patterns and the fracture network types are put forward.Fracturing effects of three types of shale gas reservoir are compared and analyzed.The results show that typical flow patterns of shale reservoirs include bilinear flow in primary and secondary fractures,linear flow in secondary fractures,bilinear flow in secondary fractures and matrix,and linear flow in matrix.The fracture network characteristics can be determined using the characteristic slopes of pressure buildup curves and curve combinations.The linear flow in early secondary fractures is increasingly distinct with an increase in primary fracture conductivity.Moreover,the bilinear flow in secondary fractures and matrix and the subsequent linear flow in the matrix occur as the propping and density of secondary fractures increase.The increase in the burial depth,in-situ stress,and stress difference corresponds to a decrease in the propping of primary fractures that expand along different directions in the shale gas wells in the Sichuan Basin.Four pressure buildup curve patterns exist in the Sichuan Basin and its periphery.The pattern of pressure buildup curves of shale reservoirs in the Yongchuan area can be described as 1/2/→1/4,indicating limited stimulated reservoir volume,poorly propped secondary fractures,and the forming of primary fractures that extend only to certain directions.The pressure buildup curves of shale reservoirs in the main block of the Fuling area show a pattern of 1/4/→1/2 or 1/2,indicating greater stimulated reservoir volume,well propped secondary fractures,and the forming of complex fracture networks.The pattern of pressure buildup curves of shale reservoirs in the Pingqiao area is 1/2/→1/4→/1/2,indicating a fracturing effect somewhere between that of the Fuling and Yongchuan areas.For reservoirs with normal pressure,it is difficult to determine fracture network characteristics from pressure buildup curves due to insufficient formation energy and limited liquid drainage.
文摘One important MN-puzzle problem is to find a sequence of up-down and right-left movements of the empty-cell so that a goal-pattern can be achieved from a given initial-pattern.The second problem is to characterize the totality of the goal-pattern from a given initial-pattern.The third problem is finding the fewest movements to achieve it.In this paper,these problems will be completely solved.
基金Supported by the National Key Research and Development Program of China(No.2022YFC2305304)the Special Financial Fund of China(No.102393220020020000029).
文摘Introduction:Leptospirosis has historically been a severe public health concern across multiple Chinese provinces.Despite an overall decline in incidence in recent years,the disease continues to exhibit fluctuations and occasionally triggers localized outbreaks.This study aimed to characterize the demographic and spatiotemporal patterns of leptospirosis in Anhui Province—a historically significant epidemic region—from 2004 to 2023,to investigate potential climatic and environmental risk factors,and to identify critical targets for disease prevention and control.Methods:Spatiotemporal cluster analysis was conducted using SaTScan software.Spearman correlation analysis was performed using SPSS to examine the short-term lagged effects of rainfall,temperature,and normalized difference vegetation index(NDVI)on leptospirosis incidence in the highrisk counties of Huaiyuan and Jingde.Results:A total of 458 leptospirosis cases were reported across Anhui Province during the 20-year study period.Middle-aged individuals(40–59 years),males,and agricultural workers constituted the primary high-risk populations.Spatiotemporal scanning identified nine adjacent hotspots in southern Anhui during 2004–2012,with a subsequent shift to Huaiyuan County in the northern Huaihe River Basin during 2016–2021.Significant associations were observed between leptospirosis cases and temperature,rainfall,and NDVI in both Huaiyuan and Jingde counties.Conclusion:This study revealed significant spatial heterogeneity,distinct spatiotemporal clustering patterns,and potential climatic and environmental risk factors for leptospirosis in Anhui Province during 2004–2023.These findings provide critical information regarding target regions,high-risk populations,and climatic and environmental factors to inform early warning systems and enhance prevention and control strategies for leptospirosis.
