In order to put forward countermeasures and suggestions of reform and innovation on the supply system of preschool education in China,the current change process of China’s preschool education supply system is analyze...In order to put forward countermeasures and suggestions of reform and innovation on the supply system of preschool education in China,the current change process of China’s preschool education supply system is analyzed using the historical analysis method.It is believed that there are still some outstanding problems in the supply system of the preschool education in China at present.According to the theory of supply and demand balance of economics and institutional change theory of new institutional economics,the future trend of China’s preschool education supply system is also analyzed.展开更多
植被净初级生产力(Net Primary Productivity,NPP)是反映陆地生态系统碳封存能力和环境变化的直接指标,受气候变化与人类活动的共同影响,且在不同地形上有分异性。然而,人类活动及地形对秦巴山区植被NPP变化的影响研究尚且不足。采用CAS...植被净初级生产力(Net Primary Productivity,NPP)是反映陆地生态系统碳封存能力和环境变化的直接指标,受气候变化与人类活动的共同影响,且在不同地形上有分异性。然而,人类活动及地形对秦巴山区植被NPP变化的影响研究尚且不足。采用CASA模型,综合利用线性趋势分析、转移矩阵和残差分析等方法研究了秦巴山区2001—2022年长时序NPP时空动态和地形效应,并进一步探讨了气候变化和人类活动对NPP变化的相对贡献率,主要结论如下:①秦巴山区2001—2022年的NPP空间分布表现为中间高,四周低,均值为585.11g C/m^(2),并以4.30g C m^(-2)a^(-1)的速度增加。②林地有最高的年NPP均值,而退耕还林区域具有最高的NPP增长速率(8.17g C m^(-2)a^(-1)),表明退耕还林是秦巴山区NPP增长的有效措施;③NPP随海拔和坡度变化具有明显的分异性。在海拔3400m以下,植被NPP随着高程的增加而增加,而当高程超过3400m时,植被NPP显著减少,坡度在10°—40°范围内植被NPP的多年均值和变化趋势较高;④秦巴山区NPP变化是气候变化和人类活动共同作用的结果,二者对NPP变化的相对贡献率分别为37.81%和62.19%,其中人类活动导致陇南等生态脆弱区NPP显著提高。展开更多
文摘In order to put forward countermeasures and suggestions of reform and innovation on the supply system of preschool education in China,the current change process of China’s preschool education supply system is analyzed using the historical analysis method.It is believed that there are still some outstanding problems in the supply system of the preschool education in China at present.According to the theory of supply and demand balance of economics and institutional change theory of new institutional economics,the future trend of China’s preschool education supply system is also analyzed.
文摘植被净初级生产力(Net Primary Productivity,NPP)是反映陆地生态系统碳封存能力和环境变化的直接指标,受气候变化与人类活动的共同影响,且在不同地形上有分异性。然而,人类活动及地形对秦巴山区植被NPP变化的影响研究尚且不足。采用CASA模型,综合利用线性趋势分析、转移矩阵和残差分析等方法研究了秦巴山区2001—2022年长时序NPP时空动态和地形效应,并进一步探讨了气候变化和人类活动对NPP变化的相对贡献率,主要结论如下:①秦巴山区2001—2022年的NPP空间分布表现为中间高,四周低,均值为585.11g C/m^(2),并以4.30g C m^(-2)a^(-1)的速度增加。②林地有最高的年NPP均值,而退耕还林区域具有最高的NPP增长速率(8.17g C m^(-2)a^(-1)),表明退耕还林是秦巴山区NPP增长的有效措施;③NPP随海拔和坡度变化具有明显的分异性。在海拔3400m以下,植被NPP随着高程的增加而增加,而当高程超过3400m时,植被NPP显著减少,坡度在10°—40°范围内植被NPP的多年均值和变化趋势较高;④秦巴山区NPP变化是气候变化和人类活动共同作用的结果,二者对NPP变化的相对贡献率分别为37.81%和62.19%,其中人类活动导致陇南等生态脆弱区NPP显著提高。
