让自然参与设计：一种基于自然演替的 城市自生群落改良设计途径

城市自生群落具有重要的生态服务功能与潜力，但因其外貌不被公众所接受而难以在城市公共空间中应用。将群落生态学和设计学相结合，探索一种介入栽培植物对城市自生群落进行改良，最终形成具有一定美学价值的植物群落的途径。实验以植物群落设计美学原理和种间竞争原理为依据，向已经演替1年的城市自生群落中引入63种栽培植物，按照分层的方式对群落进行改良。3年的观测结果表明，有61.9%的栽培植物可以在城市自生群落中定居并建立优势，能对76.7%的自生植物起到抑制作用，使55.8%的自生植物消失。相比城市自生群落，改良后的群落美观度提高29.4%，公众接受度提高24%，群落的物种丰富度提高至2.29倍。相比一般的人工植物群落，改良后的群落可以节约58.2%的建植成本，降低83.9%的浇水成本和67.8%的除草成本。实验证明改良设计是一种可行的群落设计途径，能有效提高群落的物种丰富度和美学价值，同时让自然参与群落设计过程，实现人与自然的合作。     

从有效需求看政府在提高居民购房能力中的作用

随着我国住房制度改革的推进,我国住房市场出现了城镇中等收入居民有强烈的购房欲望,然而又因为收入偏低而没有实际支付能力,即有效需求不足的局面。凯恩斯的消费函数具有普遍意义,就当前来说,居民对住房的消费尚属于其引致消费的一部分,政府应该通过增加中等收入居民的可支配收入来提高他们对住房的消费能力。而可支配收入的提高又有赖于税收杠杆,政府对国内居民发行公债和参与保险可以增加政府的转移支付能力,从而提高中等收入居民的可支配收入。     

Educational Development in South Sudan: Conscious Design or Spontaneous Order?

Educational development is key to the future prosperity of South Sudan. Officially the situation appears bleak with up to 50 per cent of primary‐aged children out of school, high reported dropout rates and poor attainment. Those involved in the development of education, government departments, international agencies, individuals and communities are each following one of two different approaches as they seek to extend the reach of education. The article suggests that these different approaches arise because those involved hold to either a conscious‐design or a spontaneous‐order model for educational development. The article looks at the recent development of schools in Juba, the capital of South Sudan, in the light of these two theories and finds, despite the rhetoric of the official reports, that most growth is organic and that most recent educational development is emerging spontaneously.     

Defining Capitalism

This article aims to incorporate the essential features of capitalism in an operational definition that identifies capitalism per se (pure laissez‐faire capitalism), and clearly excludes variations such as welfare capitalism and crony capitalism. By concisely highlighting the fundamental structures and mechanisms of capitalism, this essential definition facilitates defences of it that are more robust than those ordinarily offered. It also clarifies the relation between capitalism and phenomena with which it is frequently associated, and suggests a straightforward way of identifying and measuring the extent of capitalism in mixed economies.     

Anthropogenic and topographic correlates of natural vegetation cover within agricultural landscape mosaics in Turkey

Natural vegetation enhances the value of agricultural landscapes for people and wildlife. However, the role of anthropogenic versus topographic factors in driving the extent of natural vegetation cover within agricultural lands at large spatial scales remains unexplored. I assessed the influence of anthropogenic and topographic variables on the extent of agricultural mosaics with high natural vegetation cover in the country of Turkey where a large extent of natural and semi-natural vegetation is maintained by traditional agriculture. GIS layers depicting human land use, elevation, slope, roads and population data were obtained and summarized at two spatial scales, within provinces and for 100 km² grid cells covering the country’s entire agricultural land area. Average farm size was also obtained at province level. Hierarchical Partitioning was conducted to determine the independent effect of anthropogenic and topographic variables on the variation in agriculture with high natural vegetation. Slope had the largest independent effect on the variation in the proportion of agricultural mosaic with high natural vegetation cover. The extent of agricultural and settlement area also explained much of the variation in natural vegetation across both grid cells and provinces. The proportion of natural vegetation increased as human population and road density decreased across grid cells and as average farm size decreased across provinces. These results suggest that while topography is the primary driver of natural vegetation cover within agricultural mosaics in Turkey, the pressures associated with urban development and agricultural industrialization may also influence the cultural and wildlife value of agricultural landscapes.     

基于高光谱曲线的马铃薯与其他主要作物光谱差异性分析

[目的]文章以马铃薯关键生长期——结薯期为测量时点,以马铃薯和玉米、大豆、水稻为研究对象,开展高光谱曲线特征差异性研究。[方法]为更好地描述马铃薯与其他作物的光谱差异,创建高光谱反射率差异性指数、高光谱一阶导数差异性指数、高光谱红边幅值差异性指数、高光谱曲率差异性指数及高光谱植被指数差异性指数。[结果](1)马铃薯与玉米、大豆、水稻3种作物光谱曲线具有明显差异,马铃薯与玉米的反射率值在480nm附近蓝色波段位置差异最显著,差异性指数值为67.866%,与大豆、水稻的最大差异性指数值分别为49.068%、57.559%,均位于550nm附近绿色波峰位置;(2)作物光谱曲线经一阶导数变换运算,马铃薯与其他作物间的光谱差异被显著放大,在近红外波段放大程度最显著;(3)马铃薯与玉米、大豆、水稻高光谱曲率差异性指数最大值均位于波长750nm附近,差异性指数值分别为78.365%、63.471%、80.882%;(4)常用植被指数中,比值植被指数、增强型植被指数可显著区分马铃薯与玉米、大豆、水稻。[结论]差异性分析结果为农作物空间分布遥感识别提供了技术支撑。     

基于光能利用率模型的河南省冬小麦单产估算研究

[目的]快速、准确估算空间尺度上作物产量,对于评价农田生态系统对气候变化的响应、制定科学合理的粮食政策、对外粮食贸易等具有重要意义。河南省冬小麦产量占全国1/4,准确估算河南省冬小麦产量对维护国家粮食安全具有重要作用。单产估算作为农作物估产中的关键技术,也是作物估产的难点之一。[方法]文章首先利用VPM(Vegetation Photosynthesis Model)估算冬小麦NPP(Net Primary Product),结合收获指数、冬小麦收获部分的含水量、含碳量、NPP分配到地上或地下部分比例等一系列符合该研究区的经验指数,进行河南省冬小麦单产估算研究,并分析了引起模拟误差的原因。[结果]模拟单产较实测单产低估4.4%(实测单产为6 810kg/hm~2,模拟单产为6 519kg/hm~2),但两者之间存在显著相关关系,两者相关系数的平方R2=0.70(n=50,p0.01)。通过与MODIS-GPP产品获得的冬小麦单产数据比较,基于VPM模型的模拟结果优于MODIS-GPP产品。[结论]基于VPM可快速、准确估算河南省空间尺度冬小麦单产,该方法具有较好的适用性。     

Mapping changes in land use/land cover and prediction of future extension of bowé in Benin,West Africa

Desertification and land degradation are worldwide problems affecting soil, vegetation and the livelihoods of rural populations. Bowal (plural bowé) is a particular form of degraded land that occurs in tropical regions and leads to the exposure of ferricretes, which are unsuitable for farming. Bowé are more common on farmland and degraded savanna. Changes in land use/land cover were used to map a region of 6.7 million ha in northern Benin, West Africa in 1975, 1990 and 2010. The changes observed during these periods (1975–1990, 1990–2010 and 1975–2010) were used to predict the occurrence of bowé in the period up to 2050 using Markovian chain analysis. The results showed a considerable change in land use/land cover during the three periods. The types of land on which bowé occur (farmland and degraded savanna) increased in northern Benin by 5.4% per year during the period 1975–1990 and 9.5% per year during the periods 1990–2010, while the natural vegetation (forest, woodland and tree savanna) decreased by the same amount. The future scenarios also predicted the same trend. In the period 1975–1990, 1.28 million ha (26%) of natural vegetation was converted to degraded savanna and farmland while 2.23 million ha (53%) of natural vegetation was converted to degraded savanna and farmland in the period 1990–2010. Based on the dynamics recorded during the period 1975–1990 and 1990–2010 respectively, a total of 1.28 million ha (26% of the natural vegetation that was present in 1975) and 1.29 million ha (31% of the natural vegetation that was present in 1990) will be converted to farmland and degraded savanna in the study area by 2050.Thus bowalization will persist and increase in the period up to 2050. The natural vegetation could disappear if protection and restoration measures are not taken. It is thus important to take measures to stop the degradation and to implement programs to restore soils on bowé based on the soil and water conservation techniques used on highly degraded West African soils, such as zaï pit and stone rows with grass strips. Some native plants species adapted to bowalization and resistant to climate change in northern Benin (e.g. Asparagus africanus, Andropogon pseudapricus and Combretum nigricans) should be used in association with soil and water conservation techniques on bowé.     

1983-2006年南四湖湿地植被动态变化研究

采用实地调查和实验分析,结合遥感和地理信息系统技术,研究南四湖湿地在1983-2006年浮游植物和水生维管束植物的种类、分布和生物量变化.结果表明,1983-2006年,南四湖湿地植被生物量整体呈下降趋势,反映了人类的围垦、养殖等活动造成湿地初级生产力的降低,并且这种影响由湖泊外围向湖心弱化,对外围湿地的影响最大.     

宝鸡市自发性群众体育组织发展研究

随着自发性群众体育组织的产生、发展和逐渐成熟,这种体育形式的运动在基层体育组织中的地位越来越显重要,本文通过对我市自发性群众体育组织现状的调查研究,以及通过文献资料法对我国群众体育的发展现状进行概述,可以看出自发性群众体育组织很切合我国现阶段国情,能有效促进群众体育发展,并大胆预测自发性群众体育组织将成为我国群众体育发展的领头羊。