The contamination status of H5 avian influenza viruses and distribution of subtypes of H5N1 and H5N6 in poultry-related environment of Hubei areas were investigated.Urban and rural live poultry markets,poultry farms,i...The contamination status of H5 avian influenza viruses and distribution of subtypes of H5N1 and H5N6 in poultry-related environment of Hubei areas were investigated.Urban and rural live poultry markets,poultry farms,intensive livestock farms and other monitoring types of 103 counties in 17 cities were selected in Hubei.Wiping samples from cage surface,wiping samples from chopping board,fecal specimens and other environmental samples were collected and tested by real-time RT-PCR using primers and probes of influenza A,avian influenza of H5,N1 and N6 from December 2017 to March 2018.The avian influenza virus positive rate was compared among different monitoring sites,samples,time and regions.Totally,7132 environmental samples were collected in 1634 monitoring points with a positive rate of 2.24%.The positive rate of H5 avian influenza virus was the highest in urban and rural live poultry markets(3.44%,x^2=61.329,P<0.05)in 6 monitoring sites and wiping samples from chopping board(5.46%,x^2=67.072,P<0.05)in 6 sample types.H5N6 avian influenza viruses were detected more in eastern than western Hubei,and H5N6 avian influenza viruses were detected only in Xiangyang city of western Hubei.There were important high-risk places of human infection with H5 avian influenza virus in urban and rural live poultry markets and the poultry slaughtering plants.H5N6 has been the predominant subtype of H5 avian influenza viruses in the eastern and western Hubei and H5N6 avian influenza viruses were still present in a few areas of Hubei.Outbreaks of human H5N1 and H5N6 avian influenza remain at risk in Hubei province.展开更多
Ice flashover,lightning flashover and bird damage are the main reasons that cause transmission facility failure.The impact of these environmental factors on the operational risk levels of power systems should be taken...Ice flashover,lightning flashover and bird damage are the main reasons that cause transmission facility failure.The impact of these environmental factors on the operational risk levels of power systems should be taken into account in power system maintenance scheduling and operation planning.This paper studies the midshort-term risk assessment methodology considering the impact of the external environment.The relationship model between natural disasters and transmission lines is presented.The conditional outage rate model and the sampling technique are then proposed considering the correlated outage of multiple transmission lines when a disaster happens.The framework of the mid-short-term risk assessment model is outlined.A test case of Jiangxi provincial power grid validates the proposed model.The results show that the model can quantify the impact of disasters on the forced outage rate of transmission component and their outage correlation,and thus effectively revealing the mid-short-term risk of power systems.The model can facilitate a more strategic decision-making on maintenance scheduling and operation planning of power systems.展开更多
According to classical economic theory,external cost is the indirect,and uncompensated,social or environmental cost caused to an uninvolved third party that arises as an effect of another party’s activity.In light of...According to classical economic theory,external cost is the indirect,and uncompensated,social or environmental cost caused to an uninvolved third party that arises as an effect of another party’s activity.In light of this,the environmental cost caused by ballast water is considered as a negative externality.This paper aims to contribute by proposing that the environmental cost caused by ballast water can be determined through questionnaires,and that the imposition of a Pigouvian retributive tax is required to compensate for the environmental damage caused.The paper proceeds as follows.Firstly,ballast water management is discussed.Second,the environmental cost is discussed and it is asserted that it is important to have clear regulations and to update them frequently to prevent or minimize ballast water’s negative impact on the environment.Finally,it is suggested that the environmental cost caused by ballast water can be determined by questionnaires and,more specifically,by the WTP(Willingness to Pay)method,and that a special Pigouvian corrective taxation which can internalize this cost should be imposed.展开更多
Owing to a series of impacts of the "9·11 terrorist attack," the accounting scandals of big companies, Iraq War and the SARS crisis in the past two years, the world economy that might have rebounded for...Owing to a series of impacts of the "9·11 terrorist attack," the accounting scandals of big companies, Iraq War and the SARS crisis in the past two years, the world economy that might have rebounded forcefully has been on a wavering process of slow recovery.展开更多
Four Changes in World EconomyFirst,a new round of global economic growth is under way.In 2000,oil pricerose rapidly,stoek markets and exchange rates remained volatile and interestrates went up.All these disadvantages ...Four Changes in World EconomyFirst,a new round of global economic growth is under way.In 2000,oil pricerose rapidly,stoek markets and exchange rates remained volatile and interestrates went up.All these disadvantages did not undermine the foundations of worldeconomy,and the average growth rate of global gross domestic product(GDP)展开更多
Dynamic</span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> urbanization of African cities has created development traj...Dynamic</span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> urbanization of African cities has created development trajectories that face systemic challenges in the provision of sustainable and ecologically resilient urban environments. The specific challenges include extensive unregulated growth with informal settlements reflecting poor service levels and high poverty indices, inadequacy in </span><span style="font-family:Verdana;">provision</span><span style="font-family:Verdana;"> of basic services in health, water, housing, transport </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> communication infrastructure, high reliance on biomass fuels, exposure to environmental stress </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> implausible climate change coping and mitigation mechanisms among others. </span><span style="font-family:Verdana;">Review</span><span style="font-family:Verdana;"> of extensive literature and synthesis of existing bodies of knowledge on the ecological and management perspectives of urban environments revealed many gaps and understanding of urban transformation processes. The purpose of this review was to contextualize credible pathways for optimization of both ecosystem goods and services from green urban landscapes (Green infrastructure) and non-green infrastructure to ensure sustainable and ecologically resilient urban environments. Attempts were made to rationalize and validate through discussions the benefits of managed urban ecosystems for African cities. </span><span style="font-family:Verdana;">On the basis of</span><span style="font-family:Verdana;"> the evidence from the literature, it is concluded that urban development trajectories that do not embrace multifaceted approaches that deliberately retain and maintain green infrastructure in the urban environment may not be cost-effective. It is recommended that systematic integration of urban forestry concepts in urban planning that involves communities, local and national governments, business entrepreneurs </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> public and private research institutions provides tenable frameworks for addressing current and future challenges of urbanization in Africa.展开更多
A high-grade green space environment will provide necessary environmental support to the outdoor activities of disadvantaged groups including the elderly and is thus helpful for promoting their physical activity level...A high-grade green space environment will provide necessary environmental support to the outdoor activities of disadvantaged groups including the elderly and is thus helpful for promoting their physical activity level and life quality.This paper takes the urban area of Dalian City as an example and divides the external environmental characteristics of a green space into three aspects including the diversity degree of facilities,the richness level of street functions,and the mixing degree of land use.Based on the data of a survey on activities by elderly in green space,the paper conducts an in-depth study on the statistical correlation between the external environmental characteristics of green space and the frequency of use by the elderly.The study shows that diversified facility types around a green space are conducive to a rise in the frequency of use of this space by the elderly,out of which the effect of functional facilities such as school and food market is the most significant.In addition,being adjacent to streets full of daily life or being mixed with residential land use will increase the frequency of use of the green space by the elderly.This paper puts forward certain environmental upgrading strategies for green space from the perspective of external environmental characteristics in order to help build up green space that is use-friendly to the elderly.展开更多
基金the Natural Science Foundation of Hubei Province,China(No.2017CFB710).
文摘The contamination status of H5 avian influenza viruses and distribution of subtypes of H5N1 and H5N6 in poultry-related environment of Hubei areas were investigated.Urban and rural live poultry markets,poultry farms,intensive livestock farms and other monitoring types of 103 counties in 17 cities were selected in Hubei.Wiping samples from cage surface,wiping samples from chopping board,fecal specimens and other environmental samples were collected and tested by real-time RT-PCR using primers and probes of influenza A,avian influenza of H5,N1 and N6 from December 2017 to March 2018.The avian influenza virus positive rate was compared among different monitoring sites,samples,time and regions.Totally,7132 environmental samples were collected in 1634 monitoring points with a positive rate of 2.24%.The positive rate of H5 avian influenza virus was the highest in urban and rural live poultry markets(3.44%,x^2=61.329,P<0.05)in 6 monitoring sites and wiping samples from chopping board(5.46%,x^2=67.072,P<0.05)in 6 sample types.H5N6 avian influenza viruses were detected more in eastern than western Hubei,and H5N6 avian influenza viruses were detected only in Xiangyang city of western Hubei.There were important high-risk places of human infection with H5 avian influenza virus in urban and rural live poultry markets and the poultry slaughtering plants.H5N6 has been the predominant subtype of H5 avian influenza viruses in the eastern and western Hubei and H5N6 avian influenza viruses were still present in a few areas of Hubei.Outbreaks of human H5N1 and H5N6 avian influenza remain at risk in Hubei province.
基金This work was supported by Jiangxi Electric Power Corporation Key Technical Project(No.201250601).
文摘Ice flashover,lightning flashover and bird damage are the main reasons that cause transmission facility failure.The impact of these environmental factors on the operational risk levels of power systems should be taken into account in power system maintenance scheduling and operation planning.This paper studies the midshort-term risk assessment methodology considering the impact of the external environment.The relationship model between natural disasters and transmission lines is presented.The conditional outage rate model and the sampling technique are then proposed considering the correlated outage of multiple transmission lines when a disaster happens.The framework of the mid-short-term risk assessment model is outlined.A test case of Jiangxi provincial power grid validates the proposed model.The results show that the model can quantify the impact of disasters on the forced outage rate of transmission component and their outage correlation,and thus effectively revealing the mid-short-term risk of power systems.The model can facilitate a more strategic decision-making on maintenance scheduling and operation planning of power systems.
文摘According to classical economic theory,external cost is the indirect,and uncompensated,social or environmental cost caused to an uninvolved third party that arises as an effect of another party’s activity.In light of this,the environmental cost caused by ballast water is considered as a negative externality.This paper aims to contribute by proposing that the environmental cost caused by ballast water can be determined through questionnaires,and that the imposition of a Pigouvian retributive tax is required to compensate for the environmental damage caused.The paper proceeds as follows.Firstly,ballast water management is discussed.Second,the environmental cost is discussed and it is asserted that it is important to have clear regulations and to update them frequently to prevent or minimize ballast water’s negative impact on the environment.Finally,it is suggested that the environmental cost caused by ballast water can be determined by questionnaires and,more specifically,by the WTP(Willingness to Pay)method,and that a special Pigouvian corrective taxation which can internalize this cost should be imposed.
文摘Owing to a series of impacts of the "9·11 terrorist attack," the accounting scandals of big companies, Iraq War and the SARS crisis in the past two years, the world economy that might have rebounded forcefully has been on a wavering process of slow recovery.
文摘Four Changes in World EconomyFirst,a new round of global economic growth is under way.In 2000,oil pricerose rapidly,stoek markets and exchange rates remained volatile and interestrates went up.All these disadvantages did not undermine the foundations of worldeconomy,and the average growth rate of global gross domestic product(GDP)
文摘Dynamic</span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> urbanization of African cities has created development trajectories that face systemic challenges in the provision of sustainable and ecologically resilient urban environments. The specific challenges include extensive unregulated growth with informal settlements reflecting poor service levels and high poverty indices, inadequacy in </span><span style="font-family:Verdana;">provision</span><span style="font-family:Verdana;"> of basic services in health, water, housing, transport </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> communication infrastructure, high reliance on biomass fuels, exposure to environmental stress </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> implausible climate change coping and mitigation mechanisms among others. </span><span style="font-family:Verdana;">Review</span><span style="font-family:Verdana;"> of extensive literature and synthesis of existing bodies of knowledge on the ecological and management perspectives of urban environments revealed many gaps and understanding of urban transformation processes. The purpose of this review was to contextualize credible pathways for optimization of both ecosystem goods and services from green urban landscapes (Green infrastructure) and non-green infrastructure to ensure sustainable and ecologically resilient urban environments. Attempts were made to rationalize and validate through discussions the benefits of managed urban ecosystems for African cities. </span><span style="font-family:Verdana;">On the basis of</span><span style="font-family:Verdana;"> the evidence from the literature, it is concluded that urban development trajectories that do not embrace multifaceted approaches that deliberately retain and maintain green infrastructure in the urban environment may not be cost-effective. It is recommended that systematic integration of urban forestry concepts in urban planning that involves communities, local and national governments, business entrepreneurs </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> public and private research institutions provides tenable frameworks for addressing current and future challenges of urbanization in Africa.
基金supported by Open Projects Fund of Shanghai Key Laboratory of Urban Renewal and Spatial Optimization Technology(No.2019030214)National Natural Science Foundation of China(No.52078095)。
文摘A high-grade green space environment will provide necessary environmental support to the outdoor activities of disadvantaged groups including the elderly and is thus helpful for promoting their physical activity level and life quality.This paper takes the urban area of Dalian City as an example and divides the external environmental characteristics of a green space into three aspects including the diversity degree of facilities,the richness level of street functions,and the mixing degree of land use.Based on the data of a survey on activities by elderly in green space,the paper conducts an in-depth study on the statistical correlation between the external environmental characteristics of green space and the frequency of use by the elderly.The study shows that diversified facility types around a green space are conducive to a rise in the frequency of use of this space by the elderly,out of which the effect of functional facilities such as school and food market is the most significant.In addition,being adjacent to streets full of daily life or being mixed with residential land use will increase the frequency of use of the green space by the elderly.This paper puts forward certain environmental upgrading strategies for green space from the perspective of external environmental characteristics in order to help build up green space that is use-friendly to the elderly.
