森林生态系统是陆地生态系统的主体,量化森林生态系统总初级生产力(GrossPrimary Productivity,GPP)并分析其时空变化动态,有助于理解陆地碳动态发展及其对气候变化的响应机制,助力中国林业可持续发展。本研究采用敏感性分析法发现最大...森林生态系统是陆地生态系统的主体,量化森林生态系统总初级生产力(GrossPrimary Productivity,GPP)并分析其时空变化动态,有助于理解陆地碳动态发展及其对气候变化的响应机制,助力中国林业可持续发展。本研究采用敏感性分析法发现最大光能利用率--LUEmax是植被光合模型(VegetationPhotosynthesisMode;VPM)估算森林生态系统生产力的直接变量,敏感性高达100%。基于非线性最小二乘法,结合通量站点观测数据,优化VPM中最大光能利用率参数,并模拟了2000—2015年中国森林生态系统总初级生产力,进而分析了林区16年来GPP时空变化特征及其主要环境影响因子。结果表明:森林GPP年均值为1294.62 g C/m^(2)/year,以6.57 g C/m^(2)/year2(P<0.05)的速率显著上升,其环境因子光合有效辐射呈现增加趋势,而温度和降水量的年际变化不明显,森林GPP与光合有效辐射和温度呈显著正相关,与降水量呈负相关;在空间尺度上,在空间上超过80%区域的森林GPP年际变异由光合有效辐射和温度年际变异控制,光照和温度是我国森林生态系统GPP的主要影响因子。展开更多
The urban environmental quality remains currently difficult to be assessed because of overlapping of several natural and anthropogenic factors having socio-economic and environmental outstanding impacts. The fast deve...The urban environmental quality remains currently difficult to be assessed because of overlapping of several natural and anthropogenic factors having socio-economic and environmental outstanding impacts. The fast developing and uncontrolled urbanization is behind the development of some negative side effects on the urban environment. Many studies demonstrate the ability of remote sensing and GIS （geographic information system） to monitor urban environment quality. Casablanca, Morocco＇s economical capital is facing a fast growing demographic development amplified by a massive rural depopulation and all this in an anarchic way. This growth of increased urban activity comes often with the proliferation of informal settlement and shantytown to the detriment of farming areas and green spaces. This study is made possible by using a SPOT-5 image of Casablanca city, taken March 16, 2004 merged with 2.5 m spatial resolution and census data. Indicators were defined and listed in social, economic and environmental categories. An index of environmental quality in Casablanca city for the 17 urban municipalities was calculated after the standardization and weighting of indicators used. The results may be useful to city managers and planners who are concerned with urban environment quality issues and sustainable development.展开更多
Elucidation of the relationships between genetic polymorphisms and environmental exposures can provide insights into the pathways and mechanisms underlying complex traits. A new approach was used to detect G×E （...Elucidation of the relationships between genetic polymorphisms and environmental exposures can provide insights into the pathways and mechanisms underlying complex traits. A new approach was used to detect G×E （gene-environment） interactions involved in human skin pigmentation variation to better understand the adaptive evolution of skin pigmentation. Specifically, we used genetic engineering, remote UVR （ultraviolet radiation） sensing and GIS （geographic information systems） to integrate the analysis of genetic and environmental factors into a coherent biological framework. Since we expected to generate large datasets for this multidimensional analysis, we used PCA （principal components analysis） as a spatial statistical analysis technique for analyzing the G×E interactions. The results suggest that skin pigmentation may be affected by mutations induced by UVR and support the hypothesis that global variation in skin pigmentation may be the result of localized adaptation to different UVR conditions via natural selection. Analyzing the relationships between heterozygous frequencies for SNP （single nucleotide polymorphism） loci and seasonal UVR levels as the environment changes will help elucidate the selective mechanisms involved in the UVR-induced evolution of skin pigmentation. Skin pigmentation fulfills the criteria for a successful evolutionary G×E interactions model.展开更多
文摘森林生态系统是陆地生态系统的主体,量化森林生态系统总初级生产力(GrossPrimary Productivity,GPP)并分析其时空变化动态,有助于理解陆地碳动态发展及其对气候变化的响应机制,助力中国林业可持续发展。本研究采用敏感性分析法发现最大光能利用率--LUEmax是植被光合模型(VegetationPhotosynthesisMode;VPM)估算森林生态系统生产力的直接变量,敏感性高达100%。基于非线性最小二乘法,结合通量站点观测数据,优化VPM中最大光能利用率参数,并模拟了2000—2015年中国森林生态系统总初级生产力,进而分析了林区16年来GPP时空变化特征及其主要环境影响因子。结果表明:森林GPP年均值为1294.62 g C/m^(2)/year,以6.57 g C/m^(2)/year2(P<0.05)的速率显著上升,其环境因子光合有效辐射呈现增加趋势,而温度和降水量的年际变化不明显,森林GPP与光合有效辐射和温度呈显著正相关,与降水量呈负相关;在空间尺度上,在空间上超过80%区域的森林GPP年际变异由光合有效辐射和温度年际变异控制,光照和温度是我国森林生态系统GPP的主要影响因子。
文摘The urban environmental quality remains currently difficult to be assessed because of overlapping of several natural and anthropogenic factors having socio-economic and environmental outstanding impacts. The fast developing and uncontrolled urbanization is behind the development of some negative side effects on the urban environment. Many studies demonstrate the ability of remote sensing and GIS （geographic information system） to monitor urban environment quality. Casablanca, Morocco＇s economical capital is facing a fast growing demographic development amplified by a massive rural depopulation and all this in an anarchic way. This growth of increased urban activity comes often with the proliferation of informal settlement and shantytown to the detriment of farming areas and green spaces. This study is made possible by using a SPOT-5 image of Casablanca city, taken March 16, 2004 merged with 2.5 m spatial resolution and census data. Indicators were defined and listed in social, economic and environmental categories. An index of environmental quality in Casablanca city for the 17 urban municipalities was calculated after the standardization and weighting of indicators used. The results may be useful to city managers and planners who are concerned with urban environment quality issues and sustainable development.
文摘Elucidation of the relationships between genetic polymorphisms and environmental exposures can provide insights into the pathways and mechanisms underlying complex traits. A new approach was used to detect G×E （gene-environment） interactions involved in human skin pigmentation variation to better understand the adaptive evolution of skin pigmentation. Specifically, we used genetic engineering, remote UVR （ultraviolet radiation） sensing and GIS （geographic information systems） to integrate the analysis of genetic and environmental factors into a coherent biological framework. Since we expected to generate large datasets for this multidimensional analysis, we used PCA （principal components analysis） as a spatial statistical analysis technique for analyzing the G×E interactions. The results suggest that skin pigmentation may be affected by mutations induced by UVR and support the hypothesis that global variation in skin pigmentation may be the result of localized adaptation to different UVR conditions via natural selection. Analyzing the relationships between heterozygous frequencies for SNP （single nucleotide polymorphism） loci and seasonal UVR levels as the environment changes will help elucidate the selective mechanisms involved in the UVR-induced evolution of skin pigmentation. Skin pigmentation fulfills the criteria for a successful evolutionary G×E interactions model.
