SPATIAL-TEMPORAL CHANGES AND TRENDS OF AGEING IN CHINA

This study focuses on the development stages of ageing and its regional differences in China based on examination of official statistics and documents. The development of ageing in China has experienced three major stages. Firstly, in the 1950s, low coefficient of elderly population （over 65 years） paced up to primary adult type. Secondly, there was a deeply drop of the elderly population because of natural disaster and political factors in the 1960s. Thirdly, from the 1970s to the end of 20th century, the constant increasing of elderly coefficient made China close to elderly society. With statistic data of population, Logistic model is used to simulate the future development of ageing, and two characteristics of development of ageing are presented. Firstly, as for ageing from 2005 to 2050, the elderly coefficient will grow up significantly from 8.48% to 16.30%. Secondly, after 2025, the increasing rate of elderly coefficient will slow down gradually. The regional differences of elderly population in China can be summarized as follows： 1） the eastern China possesses higher elderly coefficient and huger elder population than the western China; 2） about 47.4% of municipalities and provinces in the eastern China become elderly especially Shanghai, Zhejiang Province, Jiangsu Province, Beijing, Tianjin and Shandong Province; 3） ageing intensity is higher in rural area than urban area but getting close each other, and there are more elderly people in rural area than in urban area. Therefore, these will arose aged care problems, and it becomes important issue to establish the social security system in rural areas as soon as possible for elderly people.     

Change of Cultivated Land and Its Implications on Food Security in China

1 Introduction FAO defined food security not only in terms of access to and availability of food, but also in terms of resources distribution to produce food and the purchasing power on food where it is not produced (Shi et al., 1996; Ning, 2004). Obviously, to guarantee everyone adequate food is the primary aim and most important content of food security (Xie et al., 1999). Thus, to increase food supply is a precondition for food security by domestic food production and international food t…     

统筹发展内涵挖潜全面推进土地节约和集约利用

杭州人多地少,全市丘陵山地面积占总面积65%,人均耕地仅为0.46亩.随着我市社会经济快速发展,城市人口不断增加,人地矛盾更加突出.截止2003年底,2003年市区人均土地面积只有786平方米,均低于长三角主要城市.市区实际可供开发利用的土地资源仅为13.67万亩.近年来,市区平均每年建设用地占用耕地为1.82万亩.     

璀璨的东方之珠——香港节约集约利用土地资源见闻

香港素称“东方明珠”，总面积为1070平方公里，人口超过660万。香港分为4个部分——香港岛、新界、九龙和离岛。九龙是位于北边港口的半岛，尖沙嘴一带是游客聚集的地方。香港岛的面积为78平方公里，只占全香港陆地面积的7％，是主要的商业地区，观光旅馆和旅游景点众多。新界的面积约有980平方公里，占香港陆地面积的91％。     

土壤科学与环境保护

地球生物圈的重要组成部分——土壤，是对人类生计和生活都至关重要的动态生态系统。人类文明的崛起和衰败，无不与对土壤的合理利用和管理失当有关。据全球土壤分布地理及气候情况，适合农作物生长的土地并不多，然而全球人口的增长下世纪有可能达到１００亿。下个世纪，整个人类所面临的最大挑战将是如何在最贫困的国家中对付饥饿的幽灵、制止环境恶化以及人口的高速增长。本文力求阐明解决全球粮食需求、土壤对污水的处理和防止环境进一步恶化的方法。只有多学科的共同努力才能达到预期的目的。     

浅谈地质灾害的主要类型

地质灾害是指包括自然因素或者人为活动引发的危害人民生命和财产安全的山体崩塌、滑坡、泥石流、地面塌陷、地裂缝、地面沉降等与地质作用有关的灾害.我国幅员辽阔,人口众多,气候多变,地形地貌和地质条件非常复杂,是世界上地质灾害危害最严重的国家之一.