Impacts of socio-economic factors on sediment yield in the Upper Yangtze River

In recent years, the role of human activities in changing sediment yield has become more apparent for the construction of hydraulic engineering and water conservation projections in the Upper Yangtze River, but it has not been evaluated at the macro scale. Taking Sichuan Province and Chongqing City as an example, this paper studies the relationship between socio-economic factors and sediment yield in the Upper Yangtze River based on section data in 1989 and 2007. The results show that sediment yield is significantly correlated with population density and cultivated area, in which the former appears to be more closely related to sediment yield. Moreover, in the relation of sediment yield vs. population density, a critical value of population density exists, below which the sediment yield increases with the increase of population density and over which the sediment yield increases with the decrease of population density. The phenomenon essentially reflects the influence of natural factors, such as topography, precipitation and soil property, and some human activities on sediment yield. The region with a higher population density than critical value is located in the east of the study area and is characterized by plains, hills and low mountains, whereas the opposite is located in the west and characterized by middle and high mountains. In the eastern region, more people live on the lands with a low slope where regional soil erosion is slight; therefore, sediment yield is negatively related with population density. In contrast, in the western region, the population tends to aggregate in the areas with abundant soil and water resources which usually lead to a higher intensity of natural erosion, and in turn, high-intensity agricultural practices in these areas may further strengthen local soil erosion. It is also found that population tends to move from the areas with bad environment and high sediment yield to the areas with more comfortable environment and less sediment yield. The natural factors have greater influence on sediment yield of western region than that of eastern region. Generally, the natural factors play a dominant role on sediment yield in the Upper Yangtze River.

Industrial development and land use/cover change and their effects on local environment: a case study of Changshu in eastern coastal China

The interactions among industrial development, land use/cover change (LUCC), and environmental effects in Changshu in the eastern coastal China were analyzed using high-resolution Landsat TM data in 1990, 1995, 2000, and 2006, socio-economic data and water environmental quality monitoring data from research institutes and governmental departments. Three phases of industrial development in Changshu were examined (i.e., the three periods of 1990 to 1995, 1995 to 2000, and 2000 to 2006). Besides industrial development and rapid urbanization, land use/cover in Changshu had changed drastically from 1990 to 2006. This change was characterized by major replacements of farmland by urban and rural settlements, artificial ponds, forested and constructed land. Industrialization, urbanization, agricultural structure adjustment, and rural housing construction were the major socio-economic driving forces of LUCC in Changshu. In addition, the annual value of ecosystem services in Changshu decreased slightly during 1990-2000, but increased significantly during 2000-2006. Nevertheless, the local environmental quality in Changshu, especially in rural areas, has not yet been improved significantly. Thus, this paper suggests an increased attention to fully realize the role of land supply in adjustment of environment-friendly industrial structure and urban-rural spatial restructuring, and translating the land management and environmental protection policies into an optimized industrial distribution and land-use pattern.

A coupling model for terrestrial processes in arid areas and its application

In this paper, the importance of investigation on terrestrical processes in arid areas for mankind's living environment protection and local economy development as well as its present state of the art are elucidated. A coupling model, which evaluates heat, mass, momentum and radiative fluxes in the SPAC system, is developed for simulating microclimate over plant and bare soil. Especially, it is focussed on the details of turbulence transfer. For illustration, numerical simulation of the water-heat exchange processes at Shapotou Observatory, GAS, Ninxia Province are conducted, and the computational results show that the laws of land-surface processes are rather typical in the arid areas.

Studies on terrestrial interface processes in arid areas, China

In the present paper, we have elucidated the importance of energy and water cycling in arid areas to investigate global climate and local economics. Then, we were concerned with the physical arguments as how to stratify the soil, and the stability of the numerical scheme in the mathematical model for predicting temperature variation and water motion. Furthermore, we discuss the methods to estimate evaporation in arid areas. Numerical simulation of energy and water cycling at the Acsu Observatory, CAS, Xinjiang province and Shapuotou Observatory, CAS, Ningxia Province are conducted as case studies. The results show that the laws of terrestrial processes are rather typical in these arid areas. Planting drought-endurable trees can alleviate unfavourable conditions to a certain extent. (C) 1997 Academic Press Limited.

Acute rejection is associated with antibodies to non-Gal antigens in baboons using Gal-knockout pig kidneys

We transplanted kidneys from alpha 1,3-galactosyltransferase knockout (GalT-KO) pigs into six baboons using two different immunosuppressive regimens, but most of the baboons died from severe acute humoral xenograft rejection. Circulating induced antibodies to non-Gal antigens were markedly elevated at rejection, which mediated strong complement-dependent cytotoxicity against GaIT-KO porcine target cells. These data suggest that antibodies to non-Gal antigens will present an additional barrier to transplantation of organs from GaIT-KO pigs to humans.