“Human-elephant conflict(HEC)”,the alarming issue,in present day context has attracted the attention of environmentalists and policy makers.The rising conflict between human beings and wild elephants is common in Bu...“Human-elephant conflict(HEC)”,the alarming issue,in present day context has attracted the attention of environmentalists and policy makers.The rising conflict between human beings and wild elephants is common in Buxa Tiger Reserve(BTR)and its adjoining area in West Bengal State,India,making the area volatile.People’s attitudes towards elephant conservation activity are very crucial to get rid of HEC,because people’s proximity with wild elephants’habitat can trigger the occurrence of HEC.The aim of this study is to conduct an in-depth investigation about the association of people’s attitudes towards HEC with their locational,demographic,and socio-economic characteristics in BTR and its adjoining area by using Pearson’s bivariate chi-square test and binary logistic regression analysis.BTR is one of the constituent parts of Eastern Doors Elephant Reserve(EDER).We interviewed 500 respondents to understand their perceptions to HEC and investigated their locational,demographic,and socio-economic characteristics including location of village,gender,age,ethnicity,religion,caste,poverty level,education level,primary occupation,secondary occupation,household type,and source of firewood.The results indicate that respondents who are living in enclave forest villages(EFVs),peripheral forest villages(PFVs),corridor village(CVs),or forest and corridor villages(FCVs),mainly males,at the age of 18–48 years old,engaged with agriculture occupation,and living in kancha and mixed houses,have more likelihood to witness HEC.Besides,respondents who are illiterate or at primary education level are more likely to regard elephant as a main problematic animal around their villages and refuse to participate in elephant conservation activity.For the sake of a sustainable environment for both human beings and wildlife,people’s attitudes towards elephants must be friendly in a more prudent way,so that the two communities can live in harmony.展开更多
As a typical inland wetland, Yangguan nature reserve wetland in Dunhuang is one of the important stops of migratory route for birds, which is vulnerable and particular. Study on the community characteristics and speci...As a typical inland wetland, Yangguan nature reserve wetland in Dunhuang is one of the important stops of migratory route for birds, which is vulnerable and particular. Study on the community characteristics and species diversity of wetland has great signifi cance for biodiversity protection. Based on the fi eld investigation, the fl oristic composition, geographical elements and species diversity of wetland plants were studied in Yangguan reserve of Dunhuang. The results showed that 26 families, 56 genera and 74 species were recorded in the study area. The largest families were the Gramineae and Chenopodiaceae, accounting for 29.73% of the total. Herbs were the most abundant life-form, accounting for 77.03% of the total. The fl oral geographical elements of the plants were mainly composed of temperate zone distribution type. By using two way indicator species analysis(TWINSPAN), the vegetation in 36 sampling plots could be classifi ed into 8 communities. The species diversity indexes of communities were relatively low, but had large differences among each other. According to the importance value, the Margalef richness index(Rm) ranged from 0 to 4.200. Simpson diversity index(D) was between 0 and 0.512; Shannon diversity index(H) ranged from 0 to 1.400, and Pielou evenness index(J) was within the range of 0.538 to 1.000. The results indicated that the plant species were relatively rare and simple in general, the species diversity of communities was low, and the ecological environment was fragile in Yangguan nature reserve of Dunhuang.展开更多
This paper considers the use of the inherent structural characteristics of power system networks for improving the reactive power reserve margins for both topologically weak and strong networks. The inherent structura...This paper considers the use of the inherent structural characteristics of power system networks for improving the reactive power reserve margins for both topologically weak and strong networks. The inherent structural characteristics of the network are derived from the Schur complement of the partitioned Y-admittance matrix using circuit theory representations. Results show that topologically strong networks, operating close to the upper voltage limit could be made to increase their loadability margin by locating reactive power compensators close to generator sources, whereas topologically weak (ill conditioned) networks could be made to operate within the feasible operating limits by locating reactive power compensators on buses farther from generator sources.展开更多
The purpose of this study was to evaluate the effects of Broussonetia papyrifera(paper mulberry)invasion and land use on the floristic composition of a dry semideciduous forest in Ghana.Forty-five plots(25 m×25 m...The purpose of this study was to evaluate the effects of Broussonetia papyrifera(paper mulberry)invasion and land use on the floristic composition of a dry semideciduous forest in Ghana.Forty-five plots(25 m×25 m each),distributed among three land uses-selectively logged(SL);abandoned farmlands(AF);and an undisturbed reference(RF)-were surveyed.Results showed lower tree species richness(S),diversity(H’),evenness(S)and basal area(BA)in the SL(46,0.78,0.32 and 269.12 m2 ha-1,respectively)and AF(40,0.53,0.45,and 131.16 m^2 ha^-1)sites compared to the RF site(79,2.66,0.87,963.72 m^2 ha^-1).Similar patterns were found at the shrub layer,but no differences were observed at the herb layer.Non-metric multidimensional scaling ordination revealed distinct species composition among the land uses.The two disturbed habitats,SL and AF,were associated with increased B.papyrifera invasion particularly in the overstory,with importance value index and mean relative density of 45 and 65.03%,and 42 and 53.29%,correspondingly.However,the species was only sparsely represented in the RF site.Tree density of B.papyrifera correlated negatively with H’,S,E,BA,and native tree density and richness.These findings highlight the strong link between human land use(i.e.,logging and slash-andburn farming),invasion,and vegetation characteristics,and suggest the need to limit these disturbances to conserve biodiversity within tropical forest ecosystems.展开更多
As a significant inducement during the development of oil and gas,the role of remaining recoverable reserves is more observable especially in the later phase of development of oilfield.Depended on the production decli...As a significant inducement during the development of oil and gas,the role of remaining recoverable reserves is more observable especially in the later phase of development of oilfield.Depended on the production decline method in petroleum reservoir engineering,a new model of predicting recoverable and remaining recoverable reserves has been展开更多
The Dongsha fault- uplifted massif (for convenience . Dongsha massif from here on) is located in the northern continental shelf-slope of the South China Sea, where the water depth is 100-400m. The massif is considered...The Dongsha fault- uplifted massif (for convenience . Dongsha massif from here on) is located in the northern continental shelf-slope of the South China Sea, where the water depth is 100-400m. The massif is considered to be a part of the large-scale fault-uplifted zone directed NE and separating the Pearl River Mouth Basin into northern and southern graben areas. The sedimentary cover of the Pearl River Mouth Graben consists mainly of a 7000-10000m thick Tertiary system. A large-scale uplift occurred in the Dongsha fault-uplifted zone during Paleocene-Eocene when the lower structural layer (lower Tertiary) existed only in the small depressions of the fault-uplifted zone. The formation and evolution of the Dongsha fault-uplifted zone could be divided into: 1) the basement formation stage (J2-K1); 2) the slowly uplifted stage (K2-E22); 3) the weathering and erosion stage (E23-E31); 4) the integrated subsidence stage (E32-N12) and 5) the last uplifted stage (N13-Q). The formation of the oil and gas pools展开更多
文摘“Human-elephant conflict(HEC)”,the alarming issue,in present day context has attracted the attention of environmentalists and policy makers.The rising conflict between human beings and wild elephants is common in Buxa Tiger Reserve(BTR)and its adjoining area in West Bengal State,India,making the area volatile.People’s attitudes towards elephant conservation activity are very crucial to get rid of HEC,because people’s proximity with wild elephants’habitat can trigger the occurrence of HEC.The aim of this study is to conduct an in-depth investigation about the association of people’s attitudes towards HEC with their locational,demographic,and socio-economic characteristics in BTR and its adjoining area by using Pearson’s bivariate chi-square test and binary logistic regression analysis.BTR is one of the constituent parts of Eastern Doors Elephant Reserve(EDER).We interviewed 500 respondents to understand their perceptions to HEC and investigated their locational,demographic,and socio-economic characteristics including location of village,gender,age,ethnicity,religion,caste,poverty level,education level,primary occupation,secondary occupation,household type,and source of firewood.The results indicate that respondents who are living in enclave forest villages(EFVs),peripheral forest villages(PFVs),corridor village(CVs),or forest and corridor villages(FCVs),mainly males,at the age of 18–48 years old,engaged with agriculture occupation,and living in kancha and mixed houses,have more likelihood to witness HEC.Besides,respondents who are illiterate or at primary education level are more likely to regard elephant as a main problematic animal around their villages and refuse to participate in elephant conservation activity.For the sake of a sustainable environment for both human beings and wildlife,people’s attitudes towards elephants must be friendly in a more prudent way,so that the two communities can live in harmony.
基金Sponsored by Global Change Special Funded Project of National Key Scientifi c Research Program(2013CB956000)
文摘As a typical inland wetland, Yangguan nature reserve wetland in Dunhuang is one of the important stops of migratory route for birds, which is vulnerable and particular. Study on the community characteristics and species diversity of wetland has great signifi cance for biodiversity protection. Based on the fi eld investigation, the fl oristic composition, geographical elements and species diversity of wetland plants were studied in Yangguan reserve of Dunhuang. The results showed that 26 families, 56 genera and 74 species were recorded in the study area. The largest families were the Gramineae and Chenopodiaceae, accounting for 29.73% of the total. Herbs were the most abundant life-form, accounting for 77.03% of the total. The fl oral geographical elements of the plants were mainly composed of temperate zone distribution type. By using two way indicator species analysis(TWINSPAN), the vegetation in 36 sampling plots could be classifi ed into 8 communities. The species diversity indexes of communities were relatively low, but had large differences among each other. According to the importance value, the Margalef richness index(Rm) ranged from 0 to 4.200. Simpson diversity index(D) was between 0 and 0.512; Shannon diversity index(H) ranged from 0 to 1.400, and Pielou evenness index(J) was within the range of 0.538 to 1.000. The results indicated that the plant species were relatively rare and simple in general, the species diversity of communities was low, and the ecological environment was fragile in Yangguan nature reserve of Dunhuang.
文摘This paper considers the use of the inherent structural characteristics of power system networks for improving the reactive power reserve margins for both topologically weak and strong networks. The inherent structural characteristics of the network are derived from the Schur complement of the partitioned Y-admittance matrix using circuit theory representations. Results show that topologically strong networks, operating close to the upper voltage limit could be made to increase their loadability margin by locating reactive power compensators close to generator sources, whereas topologically weak (ill conditioned) networks could be made to operate within the feasible operating limits by locating reactive power compensators on buses farther from generator sources.
基金supported by the Institute for Environmental and Sanitation Studies,University Ghana,Legon,Accra,Ghana
文摘The purpose of this study was to evaluate the effects of Broussonetia papyrifera(paper mulberry)invasion and land use on the floristic composition of a dry semideciduous forest in Ghana.Forty-five plots(25 m×25 m each),distributed among three land uses-selectively logged(SL);abandoned farmlands(AF);and an undisturbed reference(RF)-were surveyed.Results showed lower tree species richness(S),diversity(H’),evenness(S)and basal area(BA)in the SL(46,0.78,0.32 and 269.12 m2 ha-1,respectively)and AF(40,0.53,0.45,and 131.16 m^2 ha^-1)sites compared to the RF site(79,2.66,0.87,963.72 m^2 ha^-1).Similar patterns were found at the shrub layer,but no differences were observed at the herb layer.Non-metric multidimensional scaling ordination revealed distinct species composition among the land uses.The two disturbed habitats,SL and AF,were associated with increased B.papyrifera invasion particularly in the overstory,with importance value index and mean relative density of 45 and 65.03%,and 42 and 53.29%,correspondingly.However,the species was only sparsely represented in the RF site.Tree density of B.papyrifera correlated negatively with H’,S,E,BA,and native tree density and richness.These findings highlight the strong link between human land use(i.e.,logging and slash-andburn farming),invasion,and vegetation characteristics,and suggest the need to limit these disturbances to conserve biodiversity within tropical forest ecosystems.
文摘As a significant inducement during the development of oil and gas,the role of remaining recoverable reserves is more observable especially in the later phase of development of oilfield.Depended on the production decline method in petroleum reservoir engineering,a new model of predicting recoverable and remaining recoverable reserves has been
文摘The Dongsha fault- uplifted massif (for convenience . Dongsha massif from here on) is located in the northern continental shelf-slope of the South China Sea, where the water depth is 100-400m. The massif is considered to be a part of the large-scale fault-uplifted zone directed NE and separating the Pearl River Mouth Basin into northern and southern graben areas. The sedimentary cover of the Pearl River Mouth Graben consists mainly of a 7000-10000m thick Tertiary system. A large-scale uplift occurred in the Dongsha fault-uplifted zone during Paleocene-Eocene when the lower structural layer (lower Tertiary) existed only in the small depressions of the fault-uplifted zone. The formation and evolution of the Dongsha fault-uplifted zone could be divided into: 1) the basement formation stage (J2-K1); 2) the slowly uplifted stage (K2-E22); 3) the weathering and erosion stage (E23-E31); 4) the integrated subsidence stage (E32-N12) and 5) the last uplifted stage (N13-Q). The formation of the oil and gas pools
文摘针对静止同步补偿器(static synchronous compensator,STATCOM)在无功补偿以及抑制电压频繁波动等场景下的优良特性,对STATCOM的V-I输出特性进行详细分析,说明其参与电压控制的原理以及和容抗器相比具有的优越性。为了增大STATCOM的无功裕度,使之有足够的能力应对电力系统可能出现的各种扰动,提出STATCOM接入系统的各种控制模式,以及在稳态电压控制模式下的无功置换策略和远方自动电压控制(automatic voltage control,AVC)模式下的无功置换优化方法。在远方AVC模式下,以STATCOM无功置换后出力最小和容抗器动作次数最少为目标函数,将容抗器投切次数作为罚函数引入到目标函数中,并讨论罚函数系数的确定方法和合理性。结果表明,该无功置换优化模型可以满足调压的同时最大限度地提升STATCOM的无功裕度,同时可以使容抗器的动作次数最少。
