The eco-environmental frangibility is studied by choosing the factors of land use class change and vegetation cover rate, and the equation of eco-environmental frangibility and its evaluation system are established ba...The eco-environmental frangibility is studied by choosing the factors of land use class change and vegetation cover rate, and the equation of eco-environmental frangibility and its evaluation system are established based on remote sensing （RS） and geographic information system technology （GIS）. Four different years of TM images are selected to calculate land use change grads and vegetation cover rate, and the relationship between the two factors and eco-environment frangibility index are build, taking Fuzhou as an example. The character of times change and space distribution of eco-environment frangibility are described. The result indicates the area of eco-environment frangibility increased 2.6% in Fuzhou during twelve years, and expands from the region between infield and forest land to forest land in space distribution.展开更多
Anatomical details are given in this article, which is performed by investigating the relationship between through the frangibility of mountain eco-environment and the status of irrational land-use in typical region o...Anatomical details are given in this article, which is performed by investigating the relationship between through the frangibility of mountain eco-environment and the status of irrational land-use in typical region of debris flow in Dongchuan district, Kunming city, yunnan Province. This analysis is extended to the relationship between vicissitude of mountain disasters and the frangibility of mountain environment. The relatively coupling action of a vicious circle is a evolving characteristic by debris flow sand-gravel there. The eco-security is being faced with serious challenge. The tactics of eco-security has been constructed since 1980s. Thus, the eco-environrnent can gradually be repaired and optimized to achieve a fine circle.展开更多
By analyzing current situation of the Caihai Wetland, combining with "3S" technology, theory of ecosystem health, landscape ecology theory, applying the model of Pressure–State–Response, this paper assesse...By analyzing current situation of the Caihai Wetland, combining with "3S" technology, theory of ecosystem health, landscape ecology theory, applying the model of Pressure–State–Response, this paper assessed dynamic changes of ecological frangibility of the Caohai Wetland in Guizhou in 1992, 2000 and 2013. The results showed that the wetland ecosystem had sound principal functions, but also witnessed different degrees of degradation. The ratio of basic complete ecosystem landscape area in the Caohai Wetland reduced from 70.56% in 1992 to 66.26% in 2013, and the ratio of destructed landscape area increased from 12.11% in 1992 to 13.38% in 2013.展开更多
Background We investigated differences in intracranial embolus distribution through communicating arteries in relation to supra-aortic vessel(SAV)patency.Methods For this experimental analysis,we created a silicone mo...Background We investigated differences in intracranial embolus distribution through communicating arteries in relation to supra-aortic vessel(SAV)patency.Methods For this experimental analysis,we created a silicone model of the extracranial and intracranial circulations using a blood-mimicking fluid under physiological pulsatile flow.We examined the sequence of embolus lodgment on injecting 104 frangible clot analogues(406 emboli)through the right internal carotid artery(CA)as SAV patency changed:(a)all SAV patent(baseline),(b)emboli from a CA occlusion,(c)emboli contralateral to a CA occlusion and(d)occlusion of the posterior circulation.The statistical analysis included a descriptive analysis of thrombi location after occlusion(absolute and relative frequencies).Sequences of occlusions were displayed in Sankey flow charts for the four SAV conditions.Associations between SAV conditions and occlusion location were tested by Fisher’s exact test.Two-sided p values were compared with a significance level of 0.05.Results The total number of emboli was 406(median fragments/clot:4(IQR:3-5)).Embolus lodgment was dependent on SAV patency(p<0.0001).In all scenarios,embolism lodging in the anterior cerebral artery(ACA)occurred after a previous middle cerebral artery(MCA)embolism(MCA first lodge:96%,100/104).The rate of ipsilateral ACA embolism was 28.9%(28/97)at baseline,decreasing significantly when emboli originated from an occluded CA(16%,14/88).There were more bihemispheric embolisations in cases of contralateral CA occlusion(37%,45/122),with bilateral ACA embolisms preceding contralateral MCA embolism in 56%of cases(14/25 opposite MCA and ACA embolism).Conclusions All emboli in the ACA occurred after a previous ipsilateral MCA embolism.Bihemispheric embolisms were rare,except when there was a coexisting occlusion in either CA,particularly in cases of a contralateral CA occlusion.展开更多
The west Jilin Province is a typical area in the ecotone between agriculture and animal husbandry,with a frangible eco-environment.With respect to the three aspects of water resource,natural disasters and land degrada...The west Jilin Province is a typical area in the ecotone between agriculture and animal husbandry,with a frangible eco-environment.With respect to the three aspects of water resource,natural disasters and land degradation,10 indices were selected to establish a matter-element model for the assessment of eco-environmental frangibility in the west Jilin Province.The results indicate that during 1985–2000,Qian’an,Fuyu,and Changling had the least frangibility(level Ⅰ),followed by Da’an and Qianguo(level Ⅱ),and Taobei,Zhenlai,Taonan,and Tongyu had the highest frangibility(level Ⅲ).On the whole,the counties in Songyuan city were less frangible than those in Baicheng city.Different counties had different frangibilities to environmental factors,e.g.,Da’an and Tongyu were frangible in water resource conditions;Taobei,Zhenlai,Taonan,Tongyu and Qian’an suffered most from natural disasters;while Taobei,Taonan and Qianguo were threatened by severe land degradation.展开更多
基金the Department of Science and Technology of Fujian Province (2003I015)Open Foundation of State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing (WCL (02)0104)
文摘The eco-environmental frangibility is studied by choosing the factors of land use class change and vegetation cover rate, and the equation of eco-environmental frangibility and its evaluation system are established based on remote sensing （RS） and geographic information system technology （GIS）. Four different years of TM images are selected to calculate land use change grads and vegetation cover rate, and the relationship between the two factors and eco-environment frangibility index are build, taking Fuzhou as an example. The character of times change and space distribution of eco-environment frangibility are described. The result indicates the area of eco-environment frangibility increased 2.6% in Fuzhou during twelve years, and expands from the region between infield and forest land to forest land in space distribution.
基金the National Natural Science Foundation of China (40671026)
文摘Anatomical details are given in this article, which is performed by investigating the relationship between through the frangibility of mountain eco-environment and the status of irrational land-use in typical region of debris flow in Dongchuan district, Kunming city, yunnan Province. This analysis is extended to the relationship between vicissitude of mountain disasters and the frangibility of mountain environment. The relatively coupling action of a vicious circle is a evolving characteristic by debris flow sand-gravel there. The eco-security is being faced with serious challenge. The tactics of eco-security has been constructed since 1980s. Thus, the eco-environrnent can gradually be repaired and optimized to achieve a fine circle.
基金Sponsored by National Natural Science Foundation of China(41161002)Guizhou Province Governor Foundation(2011No.46)Guizhou Project of Ministry of Environmental Protection"RS Survey and Assessment of the Decadal Change of Ecological Environment"
文摘By analyzing current situation of the Caihai Wetland, combining with "3S" technology, theory of ecosystem health, landscape ecology theory, applying the model of Pressure–State–Response, this paper assessed dynamic changes of ecological frangibility of the Caohai Wetland in Guizhou in 1992, 2000 and 2013. The results showed that the wetland ecosystem had sound principal functions, but also witnessed different degrees of degradation. The ratio of basic complete ecosystem landscape area in the Caohai Wetland reduced from 70.56% in 1992 to 66.26% in 2013, and the ratio of destructed landscape area increased from 12.11% in 1992 to 13.38% in 2013.
文摘Background We investigated differences in intracranial embolus distribution through communicating arteries in relation to supra-aortic vessel(SAV)patency.Methods For this experimental analysis,we created a silicone model of the extracranial and intracranial circulations using a blood-mimicking fluid under physiological pulsatile flow.We examined the sequence of embolus lodgment on injecting 104 frangible clot analogues(406 emboli)through the right internal carotid artery(CA)as SAV patency changed:(a)all SAV patent(baseline),(b)emboli from a CA occlusion,(c)emboli contralateral to a CA occlusion and(d)occlusion of the posterior circulation.The statistical analysis included a descriptive analysis of thrombi location after occlusion(absolute and relative frequencies).Sequences of occlusions were displayed in Sankey flow charts for the four SAV conditions.Associations between SAV conditions and occlusion location were tested by Fisher’s exact test.Two-sided p values were compared with a significance level of 0.05.Results The total number of emboli was 406(median fragments/clot:4(IQR:3-5)).Embolus lodgment was dependent on SAV patency(p<0.0001).In all scenarios,embolism lodging in the anterior cerebral artery(ACA)occurred after a previous middle cerebral artery(MCA)embolism(MCA first lodge:96%,100/104).The rate of ipsilateral ACA embolism was 28.9%(28/97)at baseline,decreasing significantly when emboli originated from an occluded CA(16%,14/88).There were more bihemispheric embolisations in cases of contralateral CA occlusion(37%,45/122),with bilateral ACA embolisms preceding contralateral MCA embolism in 56%of cases(14/25 opposite MCA and ACA embolism).Conclusions All emboli in the ACA occurred after a previous ipsilateral MCA embolism.Bihemispheric embolisms were rare,except when there was a coexisting occlusion in either CA,particularly in cases of a contralateral CA occlusion.
基金The project was supported by the National Basic Research Priorities Program(973 Program)(No.2004CB418507).
文摘The west Jilin Province is a typical area in the ecotone between agriculture and animal husbandry,with a frangible eco-environment.With respect to the three aspects of water resource,natural disasters and land degradation,10 indices were selected to establish a matter-element model for the assessment of eco-environmental frangibility in the west Jilin Province.The results indicate that during 1985–2000,Qian’an,Fuyu,and Changling had the least frangibility(level Ⅰ),followed by Da’an and Qianguo(level Ⅱ),and Taobei,Zhenlai,Taonan,and Tongyu had the highest frangibility(level Ⅲ).On the whole,the counties in Songyuan city were less frangible than those in Baicheng city.Different counties had different frangibilities to environmental factors,e.g.,Da’an and Tongyu were frangible in water resource conditions;Taobei,Zhenlai,Taonan,Tongyu and Qian’an suffered most from natural disasters;while Taobei,Taonan and Qianguo were threatened by severe land degradation.
