The gap between the projected urban areas in the current trend(UAC)and those in the sustainable scenario(UAS)is a critical factor in understanding whether cities can fulfill the requirements of sustainable development...The gap between the projected urban areas in the current trend(UAC)and those in the sustainable scenario(UAS)is a critical factor in understanding whether cities can fulfill the requirements of sustainable development.However,there is a paucity of knowledge on this cutting-edge topic.Given the extensive and rapid urbanization in the United States(U.S.)over the past two centuries,accurately measuring this gap between UAS and UAC is of critical importance for advancing future sustainable urban development,as well as having significant global implications.This study finds that although the 740 U.S.cities have a large UAC in 2100,these cities will encom pass a significant gap from UAC to UAS(approximately 165,000 km2),accounting for 30%UAC at that time.The study also reveals the spatio-temporal heterogeneity of the gap.The gap initially increases before reaching a inflection point in 2090,and it disparates greatly from−100%to 240%at city level.While cities in the Northwestern U.S.maintain UAC that exceeds UAS from 2020 to 2100,cities in other regions shift from UAC that exceeds UAS to UAC that falls short of UAS.Filling the gap without additional urban growth planning could lead to a reduction of crop production ranging from 0.3%to 3%and a 0.68%loss of biomass.Hence,dynamic and forward-looking urban planning is essential for addressing the challenges of sustainable development posed by urbanization,both within the U.S.and globally.展开更多
Yin-mountain Hilly Area is one of the ideal regions for potato （Solanum tuberosum） production in China. However, potato yield is severely limited as a result of rain-fed crop mode due to water deficiency, as well as...Yin-mountain Hilly Area is one of the ideal regions for potato （Solanum tuberosum） production in China. However, potato yield is severely limited as a result of rain-fed crop mode due to water deficiency, as well as an inadequate farming practices. In this study, yield gaps were determined by using attainable yield （Ya） as a benchmark under optimized management practices, i.e., micro-ridge and side planting with plastic-mulching （MS）, and flat planting with plastic-mulching （PM）. The yields under MS and PM modes are defined as Yal and Ya2, respectively. Under the same field with MS and PM modes but different densities and fertilizer usages and so on, it was defined as simulated farmers＇ practices. The yield of simulated farmers＇ practices （Yfl） reached 57.3 and 69.6% of Yal and Ya2, respectively, while the average yield of 298 randomly surveyed farmers （Yf2） reached only 37.0 and 47.8% of Yal and Ya2 for rain-fed potato, respectively. The gaps of water use efficiency exhibited similar pattern. Further analysis shows that improper measures in rainwater conservation and accumulation, and other management practices contributed to 18.5, 18.2, and 42.6% of yield gap between Yal and Yf2. Improper nutrition management, including overuse of nitrogen and the deficiency of phosphorus andpotassium supplication, was one of the important reasons of yield gap. The results indicate the possibilities of increasing rain-fed potato yields by optimized water and fertilizermanagements in the Yin-mountain Hilly Area.展开更多
The increasingly widening income gap between urban and rural areas is affected by many factors. Using the stepwise regression analysis,we find that urbanization level,socio-economic development,education level,financi...The increasingly widening income gap between urban and rural areas is affected by many factors. Using the stepwise regression analysis,we find that urbanization level,socio-economic development,education level,financial development scale and financial development efficiency have the greatest impact on the income gap between urban and rural areas. By cointegration test,it is found that there is a long-term equilibrium relationship between these five variables and the income gap between urban and rural areas. We build the state-space model to research the dynamic impact of these factors on the income gap between urban and rural areas. The results show that by improving the level of urbanization,we can effectively narrow the income gap between urban and rural areas,while socio-economic development,the improvement of education level,expansion of financial development scale and financial development efficiency all significantly expand the income gap between urban and rural areas.展开更多
This paper investigates the effect of launching multiple weapons against an area target of normally distributed elements. We provide an analytical form of the average damage fraction and then apply it to obtain optima...This paper investigates the effect of launching multiple weapons against an area target of normally distributed elements. We provide an analytical form of the average damage fraction and then apply it to obtain optimal aimpoints. To facilitate the computational efforts in practice, we also consider optimizations over given constrained patterns of aimpoints. Finally, we derive scaling laws for optimal aimpoints and optimal damage fraction with respect to the radius of the area target.展开更多
The development of a territory always followed by population growth and increasing the life necessities of the society. This condition makes increasing transportation activity that causes environmental pollution. Poll...The development of a territory always followed by population growth and increasing the life necessities of the society. This condition makes increasing transportation activity that causes environmental pollution. Pollutants that are released by vehicle such as CO （carbon monoxide）, SO2 （sulfur oxides）, NO, （nitrogen oxides） are very harmful for public health. Indonesia is a country which has the high level of air pollution from transportation. One way to deal with the air pollution is to build green area （Ruang Terbuka Hijau） around the highway. Planning of open green area must be done comprehensively. There is an appropriate way to plan green area on the road by counting the number of AADV （annual average daily vehicles） （Lalu lintas harian rata rata） and estimated the amount of pollutantt that produced by vehicles. Calculation against the ability of plants in reducing pollutants and reached a unique relation between quantities of AADV by the number of plants that are necessary for reducing pollutants resulted by the traffic. The selection of plantation based on the shape of the tree canopy that provides the capacity of a pollutants reduction. After calculations the surface area of the tree leaves, the design of green area for highway can be reached so created an environmentally friendly and safe highway.展开更多
Taking northern Jiangsu area as an example,economic disparity between urban and rural areas is described according to the data in 2000-2009 Jiangsu Statistical Yearbook.Result shows that there are significant differen...Taking northern Jiangsu area as an example,economic disparity between urban and rural areas is described according to the data in 2000-2009 Jiangsu Statistical Yearbook.Result shows that there are significant differences in the rural and urban economic development in less developed areas,which are mainly reflected in the differences in per capita income,living standard,and Engel coefficient.Reasons for urban and rural economic disparity in less developed areas are analyzed.The asymmetry and immobility of rural and urban resources have objectively caused the income gap between urban and rural residents;urban industrial development,which is faster than agricultural development,has widened the income gap between urban and rural residents;and the differences in comparative labor productivity in rural and urban areas have enlarged their income gap.Countermeasures to minimize the urban and rural economic development gap are put forward,such as deepening the reform,realizing the free flow of economic resources between urban and rural areas,developing rural areas through urban development,exerting the function of urban areas in the coordinated development of urban and rural areas,paying attention to the agriculture and rural areas,and improving the comparative labor productivity of agriculture.展开更多
Nowadays, the development of quality education has always been attached great importance in China, of which the music education has been an important part. However, serious polarization of the urban and rural basic mu...Nowadays, the development of quality education has always been attached great importance in China, of which the music education has been an important part. However, serious polarization of the urban and rural basic music education leads to all sorts of differences, thus seriously affecting the overall improvement of quality of all people. To find out the problems and the reasons of the backward in rural basic music education, this paper makes an analysis of the differences between urban and rural basic education development through a survey and a study of basic situation in music education of urban and rural elementary school in Gaocheng, Hebei province, and then puts forward thinkings and suggestions about narrowing the urban-rural music education gap on the basis of the analysis of internal and extemal problems.展开更多
The geological structure is complex in the Hohhot-Baotou area.Several earthquakes with MS≥6.0 have occurred in the area in history.This article selected the Hohhot-Baotou area as the study region and divided it into ...The geological structure is complex in the Hohhot-Baotou area.Several earthquakes with MS≥6.0 have occurred in the area in history.This article selected the Hohhot-Baotou area as the study region and divided it into 2 sub-regions,each with a spatial scope of 3°×2°,according to the spatial distribution of ML≥1.0 earthquakes occurring between January 2001 and April 2010,and the layout of the seismic network in the study region.Average velocity ratios of respective sub-regions were calculated,and comparative analysis was made on their temporal and spatial variations.Results show that there are slight differences between sub-regions in the variation amplitude of average velocity ratio curves over time,which mostly remains between 2.5% to 2.584%.In the Hohhot area,the average velocity ratio is 1.722,significantly lower than the average velocity ratio of 1.733 in the Baotou area.We preliminarily concluded that this was related to the distribution of fault structures and properties of underground media in the Hohhot area.展开更多
A substantial proportion of those affected by visceral leishmaniasis(VL)in endemic regions are children-a vulnerable group at higher risk of severe outcomes,morbidity,and mortality.It is estimated that children accoun...A substantial proportion of those affected by visceral leishmaniasis(VL)in endemic regions are children-a vulnerable group at higher risk of severe outcomes,morbidity,and mortality.It is estimated that children account for around 50%of all VL cases[1],with a similar proportion seen in high-burden areas like Eastern Africa,where half of the cases occur in those under 15 years[2],highlighting the disproportionate impact on children and economically disadvantaged populations.Afflicted children are vulnerable to malnutrition,stunting,impaired cognitive development,school absenteeism and premature death.展开更多
为加强对南海西沙海域气候变化的认识,基于采用2018—2022年南海西沙群岛地面与高空气温资料,分析了南海西沙区域气温从地面至高空垂直变化和空间分布特征,并探讨了赵述岛和永兴岛气温差异的成因。结果表明:南海西沙群岛各海岛自动气象...为加强对南海西沙海域气候变化的认识,基于采用2018—2022年南海西沙群岛地面与高空气温资料,分析了南海西沙区域气温从地面至高空垂直变化和空间分布特征,并探讨了赵述岛和永兴岛气温差异的成因。结果表明:南海西沙群岛各海岛自动气象站5年平均气温无显著差异,均为27.6℃。地面至850 h Pa的最高与最低月平均气温和西沙海域各岛礁的变化具有较好的一致性;中高层(700~300 h Pa)的最高与最低月平均气温均滞后约1个月。925 h Pa气温变化最大,500 h Pa气温变化最小。各岛礁的高温日数差异显著,其中赵述岛高温日数达317 d,永兴岛未出现过≥35℃的高温天气。永兴岛午间时段风速达到最大,午间偏大的风速促进了空气的流动,进而导致气温偏低。展开更多
基金supported by the National Natural Science Foun-dation of China(Grants No.42330103,42271469)the Ningbo Science and Technology Bureau(Grant No.2022Z081).
文摘The gap between the projected urban areas in the current trend(UAC)and those in the sustainable scenario(UAS)is a critical factor in understanding whether cities can fulfill the requirements of sustainable development.However,there is a paucity of knowledge on this cutting-edge topic.Given the extensive and rapid urbanization in the United States(U.S.)over the past two centuries,accurately measuring this gap between UAS and UAC is of critical importance for advancing future sustainable urban development,as well as having significant global implications.This study finds that although the 740 U.S.cities have a large UAC in 2100,these cities will encom pass a significant gap from UAC to UAS(approximately 165,000 km2),accounting for 30%UAC at that time.The study also reveals the spatio-temporal heterogeneity of the gap.The gap initially increases before reaching a inflection point in 2090,and it disparates greatly from−100%to 240%at city level.While cities in the Northwestern U.S.maintain UAC that exceeds UAS from 2020 to 2100,cities in other regions shift from UAC that exceeds UAS to UAC that falls short of UAS.Filling the gap without additional urban growth planning could lead to a reduction of crop production ranging from 0.3%to 3%and a 0.68%loss of biomass.Hence,dynamic and forward-looking urban planning is essential for addressing the challenges of sustainable development posed by urbanization,both within the U.S.and globally.
基金supported by the Special Industry Foundation of Ministry of Agriculture of China (201303104)the National Natural Science Foundation of China (31360502)the China Postdoctoral Science Foundation (2015M572633XB)
文摘Yin-mountain Hilly Area is one of the ideal regions for potato （Solanum tuberosum） production in China. However, potato yield is severely limited as a result of rain-fed crop mode due to water deficiency, as well as an inadequate farming practices. In this study, yield gaps were determined by using attainable yield （Ya） as a benchmark under optimized management practices, i.e., micro-ridge and side planting with plastic-mulching （MS）, and flat planting with plastic-mulching （PM）. The yields under MS and PM modes are defined as Yal and Ya2, respectively. Under the same field with MS and PM modes but different densities and fertilizer usages and so on, it was defined as simulated farmers＇ practices. The yield of simulated farmers＇ practices （Yfl） reached 57.3 and 69.6% of Yal and Ya2, respectively, while the average yield of 298 randomly surveyed farmers （Yf2） reached only 37.0 and 47.8% of Yal and Ya2 for rain-fed potato, respectively. The gaps of water use efficiency exhibited similar pattern. Further analysis shows that improper measures in rainwater conservation and accumulation, and other management practices contributed to 18.5, 18.2, and 42.6% of yield gap between Yal and Yf2. Improper nutrition management, including overuse of nitrogen and the deficiency of phosphorus andpotassium supplication, was one of the important reasons of yield gap. The results indicate the possibilities of increasing rain-fed potato yields by optimized water and fertilizermanagements in the Yin-mountain Hilly Area.
基金Supported by Humanities and Social Sciences Project of the Ministry of Education(10YJC790111)
文摘The increasingly widening income gap between urban and rural areas is affected by many factors. Using the stepwise regression analysis,we find that urbanization level,socio-economic development,education level,financial development scale and financial development efficiency have the greatest impact on the income gap between urban and rural areas. By cointegration test,it is found that there is a long-term equilibrium relationship between these five variables and the income gap between urban and rural areas. We build the state-space model to research the dynamic impact of these factors on the income gap between urban and rural areas. The results show that by improving the level of urbanization,we can effectively narrow the income gap between urban and rural areas,while socio-economic development,the improvement of education level,expansion of financial development scale and financial development efficiency all significantly expand the income gap between urban and rural areas.
文摘This paper investigates the effect of launching multiple weapons against an area target of normally distributed elements. We provide an analytical form of the average damage fraction and then apply it to obtain optimal aimpoints. To facilitate the computational efforts in practice, we also consider optimizations over given constrained patterns of aimpoints. Finally, we derive scaling laws for optimal aimpoints and optimal damage fraction with respect to the radius of the area target.
文摘The development of a territory always followed by population growth and increasing the life necessities of the society. This condition makes increasing transportation activity that causes environmental pollution. Pollutants that are released by vehicle such as CO （carbon monoxide）, SO2 （sulfur oxides）, NO, （nitrogen oxides） are very harmful for public health. Indonesia is a country which has the high level of air pollution from transportation. One way to deal with the air pollution is to build green area （Ruang Terbuka Hijau） around the highway. Planning of open green area must be done comprehensively. There is an appropriate way to plan green area on the road by counting the number of AADV （annual average daily vehicles） （Lalu lintas harian rata rata） and estimated the amount of pollutantt that produced by vehicles. Calculation against the ability of plants in reducing pollutants and reached a unique relation between quantities of AADV by the number of plants that are necessary for reducing pollutants resulted by the traffic. The selection of plantation based on the shape of the tree canopy that provides the capacity of a pollutants reduction. After calculations the surface area of the tree leaves, the design of green area for highway can be reached so created an environmentally friendly and safe highway.
文摘Taking northern Jiangsu area as an example,economic disparity between urban and rural areas is described according to the data in 2000-2009 Jiangsu Statistical Yearbook.Result shows that there are significant differences in the rural and urban economic development in less developed areas,which are mainly reflected in the differences in per capita income,living standard,and Engel coefficient.Reasons for urban and rural economic disparity in less developed areas are analyzed.The asymmetry and immobility of rural and urban resources have objectively caused the income gap between urban and rural residents;urban industrial development,which is faster than agricultural development,has widened the income gap between urban and rural residents;and the differences in comparative labor productivity in rural and urban areas have enlarged their income gap.Countermeasures to minimize the urban and rural economic development gap are put forward,such as deepening the reform,realizing the free flow of economic resources between urban and rural areas,developing rural areas through urban development,exerting the function of urban areas in the coordinated development of urban and rural areas,paying attention to the agriculture and rural areas,and improving the comparative labor productivity of agriculture.
文摘Nowadays, the development of quality education has always been attached great importance in China, of which the music education has been an important part. However, serious polarization of the urban and rural basic music education leads to all sorts of differences, thus seriously affecting the overall improvement of quality of all people. To find out the problems and the reasons of the backward in rural basic music education, this paper makes an analysis of the differences between urban and rural basic education development through a survey and a study of basic situation in music education of urban and rural elementary school in Gaocheng, Hebei province, and then puts forward thinkings and suggestions about narrowing the urban-rural music education gap on the basis of the analysis of internal and extemal problems.
基金sponsored by the Earthquare Science and Technology Spark Plan(Project No.XH12010Y)
文摘The geological structure is complex in the Hohhot-Baotou area.Several earthquakes with MS≥6.0 have occurred in the area in history.This article selected the Hohhot-Baotou area as the study region and divided it into 2 sub-regions,each with a spatial scope of 3°×2°,according to the spatial distribution of ML≥1.0 earthquakes occurring between January 2001 and April 2010,and the layout of the seismic network in the study region.Average velocity ratios of respective sub-regions were calculated,and comparative analysis was made on their temporal and spatial variations.Results show that there are slight differences between sub-regions in the variation amplitude of average velocity ratio curves over time,which mostly remains between 2.5% to 2.584%.In the Hohhot area,the average velocity ratio is 1.722,significantly lower than the average velocity ratio of 1.733 in the Baotou area.We preliminarily concluded that this was related to the distribution of fault structures and properties of underground media in the Hohhot area.
文摘A substantial proportion of those affected by visceral leishmaniasis(VL)in endemic regions are children-a vulnerable group at higher risk of severe outcomes,morbidity,and mortality.It is estimated that children account for around 50%of all VL cases[1],with a similar proportion seen in high-burden areas like Eastern Africa,where half of the cases occur in those under 15 years[2],highlighting the disproportionate impact on children and economically disadvantaged populations.Afflicted children are vulnerable to malnutrition,stunting,impaired cognitive development,school absenteeism and premature death.
文摘为加强对南海西沙海域气候变化的认识,基于采用2018—2022年南海西沙群岛地面与高空气温资料,分析了南海西沙区域气温从地面至高空垂直变化和空间分布特征,并探讨了赵述岛和永兴岛气温差异的成因。结果表明:南海西沙群岛各海岛自动气象站5年平均气温无显著差异,均为27.6℃。地面至850 h Pa的最高与最低月平均气温和西沙海域各岛礁的变化具有较好的一致性;中高层(700~300 h Pa)的最高与最低月平均气温均滞后约1个月。925 h Pa气温变化最大,500 h Pa气温变化最小。各岛礁的高温日数差异显著,其中赵述岛高温日数达317 d,永兴岛未出现过≥35℃的高温天气。永兴岛午间时段风速达到最大,午间偏大的风速促进了空气的流动,进而导致气温偏低。
