Although about two-thirds of Nepalese families depend on agriculture as their major source of income, the agriculture is mostly rain-fed and it has been adversely affected by water hazards and the subsequent degradati...Although about two-thirds of Nepalese families depend on agriculture as their major source of income, the agriculture is mostly rain-fed and it has been adversely affected by water hazards and the subsequent degradation of resources. Based on case studies from three different geographical regions in Nepal, this research examines how environmental factors cause decreasing crop production and push people to abandon agriculture and accept emigration for employment. The research findings suggest a chain of push factors starting from drought or erratic rainfall causing water hazards, which impacts on depletion of crops and livestock, losses in income and employment and increased human mobility and emigration. The paper argues that the Government of Nepal and development partners can be more effective in enabling agrarian families to cope with the water hazards and shocks by formulating pro-poor mitigation and adaptation policies and strategies,focusing both on ‘rapid-onset' and ‘slow-onset' water hazards.展开更多
In this paper we analyze the characteristics of the so-called rare earth elements （REEs） and its industrial applications. We present the policy, or lack thereof, in the countries in the Pacific Rim for its mining an...In this paper we analyze the characteristics of the so-called rare earth elements （REEs） and its industrial applications. We present the policy, or lack thereof, in the countries in the Pacific Rim for its mining and commerce, and the current and future weight that rare earth minerals will have in international trade. The technological revolution experienced over the last 25 years, has brought the REEs to the public＇s attention for being instrumental in obtaining catalysts, lasers and optical fiber, luminescent substances and LEDs, superconductors, permanent magnets, batteries and ultra-capacitors. China＇s leading position as the supplier of these minerals worldwide, and its recent export restriction policy for domestic industrial activities have driven up international prices. Price increase for REEs is leading to the need for both recycling and its replacement. It has also led other countries in the Asia Pacific Rim to prospect new potential sites on their own territories, or even to restart operations in deposits that had been previously abandoned. Those strategies will likely gain greater importance as environmental pollution problems associated with the exploitation, processing, and recovery of REEs increase.展开更多
Various environmental factors affect net primary productivity （NPP） of grassland ecosystem. Extensive reports on the effects of environmental variables on NPP can be found in literature. However, the agreement on th...Various environmental factors affect net primary productivity （NPP） of grassland ecosystem. Extensive reports on the effects of environmental variables on NPP can be found in literature. However, the agreement on the relative importance of various factors in shaping the spatial pattern of grassland NPP has not yet been reached. Here a grassland in situ NPP database comprising 602 samples in northern China for 1980-1999 was developed based on a literature review of published biomass and forage yield field measurements. Correlation analyses and dominance analysis were used to quantify the separate and combined effects of environmental variables （climate topography and soil） on spatial variation in NPP separately. Grassland NPP ranged from 4.76 g C m-2a-1 to 975.94gCm-2a-1, showing significant variations in space. NPP increased with annual precipitation and declined with annual mean temperature significantly. Specifically, precipitation had the greatest impact on deserts, followed by steppes and meadows. Grassland NPP decreased with increasing altitude because of water limitation, and positively correlated with slope, but weakly correlated with aspect. Soil quality showed positive effects on NPP. Annual precipitation was the dominant factor affecting the spatial variability of net primary productivity, followed by elevation.展开更多
文摘Although about two-thirds of Nepalese families depend on agriculture as their major source of income, the agriculture is mostly rain-fed and it has been adversely affected by water hazards and the subsequent degradation of resources. Based on case studies from three different geographical regions in Nepal, this research examines how environmental factors cause decreasing crop production and push people to abandon agriculture and accept emigration for employment. The research findings suggest a chain of push factors starting from drought or erratic rainfall causing water hazards, which impacts on depletion of crops and livestock, losses in income and employment and increased human mobility and emigration. The paper argues that the Government of Nepal and development partners can be more effective in enabling agrarian families to cope with the water hazards and shocks by formulating pro-poor mitigation and adaptation policies and strategies,focusing both on ‘rapid-onset' and ‘slow-onset' water hazards.
文摘In this paper we analyze the characteristics of the so-called rare earth elements （REEs） and its industrial applications. We present the policy, or lack thereof, in the countries in the Pacific Rim for its mining and commerce, and the current and future weight that rare earth minerals will have in international trade. The technological revolution experienced over the last 25 years, has brought the REEs to the public＇s attention for being instrumental in obtaining catalysts, lasers and optical fiber, luminescent substances and LEDs, superconductors, permanent magnets, batteries and ultra-capacitors. China＇s leading position as the supplier of these minerals worldwide, and its recent export restriction policy for domestic industrial activities have driven up international prices. Price increase for REEs is leading to the need for both recycling and its replacement. It has also led other countries in the Asia Pacific Rim to prospect new potential sites on their own territories, or even to restart operations in deposits that had been previously abandoned. Those strategies will likely gain greater importance as environmental pollution problems associated with the exploitation, processing, and recovery of REEs increase.
基金"Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues" of the Chinese Academy of Sciences(Project Number XDA05090305)
文摘Various environmental factors affect net primary productivity （NPP） of grassland ecosystem. Extensive reports on the effects of environmental variables on NPP can be found in literature. However, the agreement on the relative importance of various factors in shaping the spatial pattern of grassland NPP has not yet been reached. Here a grassland in situ NPP database comprising 602 samples in northern China for 1980-1999 was developed based on a literature review of published biomass and forage yield field measurements. Correlation analyses and dominance analysis were used to quantify the separate and combined effects of environmental variables （climate topography and soil） on spatial variation in NPP separately. Grassland NPP ranged from 4.76 g C m-2a-1 to 975.94gCm-2a-1, showing significant variations in space. NPP increased with annual precipitation and declined with annual mean temperature significantly. Specifically, precipitation had the greatest impact on deserts, followed by steppes and meadows. Grassland NPP decreased with increasing altitude because of water limitation, and positively correlated with slope, but weakly correlated with aspect. Soil quality showed positive effects on NPP. Annual precipitation was the dominant factor affecting the spatial variability of net primary productivity, followed by elevation.
