Group A streptococcus （GAS） causes a wide range of diseases in the human population. GAS diseases are more common in children than in adults, with clinical manifestations ranging from pharyngitis and impetigo to inv...Group A streptococcus （GAS） causes a wide range of diseases in the human population. GAS diseases are more common in children than in adults, with clinical manifestations ranging from pharyngitis and impetigo to invasive infections and post streptococcal sequelae, such as acute rheumatic fever and acute post-streptococcal glomerulonephritis[1]. GAS harbors a host of virulence factors that contribute to its complex pathogenicity and differences in the disease severity and frequency. M protein, one of the major virulence factors, is encoded by the emm gene induces a type of specific host immune response and confers antiphagocytic properties.展开更多
China is in the process of rapid urbanization,and wise land use is critical to the long-term sustainability of Chinese cities.Promotion of a compact city is typically believed to be helpful for sustainable land use ma...China is in the process of rapid urbanization,and wise land use is critical to the long-term sustainability of Chinese cities.Promotion of a compact city is typically believed to be helpful for sustainable land use management.However,given the fact that Chinese cities are characterized by high population densities,the applicability of a more compact solution to expand cities in China remains questionable;there is little evidence to support the many claims in its favor.In seeking to provide empirical data to explore the application of compact city theory in China,one of the key problems researchers face is the task of measuring the urban compactness,in order to objectively investigate the current characteristics of urban compactness.To meet this need,indices were developed for measuring the urban land use compactness,by which the spatial distribution characteristics of urban land use compactness were identified and applied to the Chaoyang District of Beijing.The conclusions can be made as follows:(1) comprehensive land use compactness in Chaoyang District has increased during the period of 2001-2007,especially the population density;(2) the spatial distribution of land use compactness has the characteristics of a ring structure,which shows a decreasing trend with its distance to the city center;(3) there is a strong positive correlation between urban land use compactness and location.The better the location is,the higher the land use compactness is.展开更多
Beijing's green belt policy is three-fold:fi rstly to protect farmers' interests during urbanization, secondly to control the urban expansion, and thirdly to improve the ecological environment. The planning of...Beijing's green belt policy is three-fold:fi rstly to protect farmers' interests during urbanization, secondly to control the urban expansion, and thirdly to improve the ecological environment. The planning of industrial land for green belts has thus emerged as a way to help achieve these goals during Beijing's urban growth from morphological, social, and economic perspectives. First of all, this paper introduces the implementation mechanisms of the planning of industrial land for green belts, from which it abstracts a model of land adjustment and urban-rural cooperation. Secondly, the paper analyzes the effects and current dilemmas during the implementation of the planning of industrial land for green belts. Thirdly, results are compared with other spontaneously developed industries in the rural-urban fringe area to illustrate the changes brought about by the planning. Finally, the paper proposes three measures for future improvement, including balancing the industrial land use quotas between different townships, conducting cooperative land adjustment, and encouraging spontaneously developed industrial projects.展开更多
文摘Group A streptococcus （GAS） causes a wide range of diseases in the human population. GAS diseases are more common in children than in adults, with clinical manifestations ranging from pharyngitis and impetigo to invasive infections and post streptococcal sequelae, such as acute rheumatic fever and acute post-streptococcal glomerulonephritis[1]. GAS harbors a host of virulence factors that contribute to its complex pathogenicity and differences in the disease severity and frequency. M protein, one of the major virulence factors, is encoded by the emm gene induces a type of specific host immune response and confers antiphagocytic properties.
基金financed by the National Natural Science Foundation of China(Grant nos.40635026and40901068)Special Fund from the Science and Technology Department of Beijing Municipality(Grant no.zz0922)the Postdoctoral Science Foundation of China(Grant no.200902133)
文摘China is in the process of rapid urbanization,and wise land use is critical to the long-term sustainability of Chinese cities.Promotion of a compact city is typically believed to be helpful for sustainable land use management.However,given the fact that Chinese cities are characterized by high population densities,the applicability of a more compact solution to expand cities in China remains questionable;there is little evidence to support the many claims in its favor.In seeking to provide empirical data to explore the application of compact city theory in China,one of the key problems researchers face is the task of measuring the urban compactness,in order to objectively investigate the current characteristics of urban compactness.To meet this need,indices were developed for measuring the urban land use compactness,by which the spatial distribution characteristics of urban land use compactness were identified and applied to the Chaoyang District of Beijing.The conclusions can be made as follows:(1) comprehensive land use compactness in Chaoyang District has increased during the period of 2001-2007,especially the population density;(2) the spatial distribution of land use compactness has the characteristics of a ring structure,which shows a decreasing trend with its distance to the city center;(3) there is a strong positive correlation between urban land use compactness and location.The better the location is,the higher the land use compactness is.
文摘Beijing's green belt policy is three-fold:fi rstly to protect farmers' interests during urbanization, secondly to control the urban expansion, and thirdly to improve the ecological environment. The planning of industrial land for green belts has thus emerged as a way to help achieve these goals during Beijing's urban growth from morphological, social, and economic perspectives. First of all, this paper introduces the implementation mechanisms of the planning of industrial land for green belts, from which it abstracts a model of land adjustment and urban-rural cooperation. Secondly, the paper analyzes the effects and current dilemmas during the implementation of the planning of industrial land for green belts. Thirdly, results are compared with other spontaneously developed industries in the rural-urban fringe area to illustrate the changes brought about by the planning. Finally, the paper proposes three measures for future improvement, including balancing the industrial land use quotas between different townships, conducting cooperative land adjustment, and encouraging spontaneously developed industrial projects.
