The metabolic evolution model of transportation demand for comprehensive transportation systems is put forward on the basis of a metabolic theory of ecology. In the model, the growth rates or changing rates of transpo...The metabolic evolution model of transportation demand for comprehensive transportation systems is put forward on the basis of a metabolic theory of ecology. In the model, the growth rates or changing rates of transportation volumes for the various transportation modes of a city are determined not only by the GDP per capita which reflects the size of the city itself, but also by the relationship of competition and cooperation among transportation modes. The results of empirical analysis for Chinese cities show that the allometric growth exponent in the equation for the variation rate of passenger demand volume on rail is greater than the predicted value of 1/4 in metabolic ecology, whereas the allometric growth relationship is not so evident in the equation for the variation rate of passenger demand volume on road. The changing rate of road transportation is thus mainly affected by the relationship of competition and cooperation among transportation modes for Chinese cities.展开更多
The spleen could be considered a neglected organ.To date,it has been deemed an ancillary organ in portal hypertension or an organ localization in lymphoproliferative diseases,even though it has had significant attenti...The spleen could be considered a neglected organ.To date,it has been deemed an ancillary organ in portal hypertension or an organ localization in lymphoproliferative diseases,even though it has had significant attention in infectious diseases for some time.Now,it is thought to be central in regulating the immune system,a metabolic asset and involved in endocrine function with regard to nonalcoholic fatty liver disease.The main mechanisms involved in this complex network will be critically discussed in this article.展开更多
基金The Ph.D.Programs Foundation of Ministry of Education of China(No.20060286005)China Postdoctoral Science Foundation(No.20070411018)
文摘The metabolic evolution model of transportation demand for comprehensive transportation systems is put forward on the basis of a metabolic theory of ecology. In the model, the growth rates or changing rates of transportation volumes for the various transportation modes of a city are determined not only by the GDP per capita which reflects the size of the city itself, but also by the relationship of competition and cooperation among transportation modes. The results of empirical analysis for Chinese cities show that the allometric growth exponent in the equation for the variation rate of passenger demand volume on rail is greater than the predicted value of 1/4 in metabolic ecology, whereas the allometric growth relationship is not so evident in the equation for the variation rate of passenger demand volume on road. The changing rate of road transportation is thus mainly affected by the relationship of competition and cooperation among transportation modes for Chinese cities.
文摘The spleen could be considered a neglected organ.To date,it has been deemed an ancillary organ in portal hypertension or an organ localization in lymphoproliferative diseases,even though it has had significant attention in infectious diseases for some time.Now,it is thought to be central in regulating the immune system,a metabolic asset and involved in endocrine function with regard to nonalcoholic fatty liver disease.The main mechanisms involved in this complex network will be critically discussed in this article.
