Objective: Given the unique cultural background, way of life, and physical environment of the Tibetan Plateau, this study aims to investigate the effects of health education using problem-based learning (PBL) approach...Objective: Given the unique cultural background, way of life, and physical environment of the Tibetan Plateau, this study aims to investigate the effects of health education using problem-based learning (PBL) approaches on the knowledge, attitude, practice, and coping skills of women with high-risk pregnancies in this region. Methods: 76 high-risk pregnancy cases were enrolled at Tibet’s Linzhi People’s Hospital between September 2023 and April 2024. 30 patients admitted between September 2023 and December 2023 were selected as the control group and were performed with regular patient education. 46 patients admitted between January 2024 and April 2024 were selected as the observation group and were performed regular patient education with problem-based learning approaches. Two groups’ performance on their health knowledge, attitude, practice and coping skills before and after interventions were evaluated, and patient satisfaction were measured at the end of the study. Results: There was no statistical significance (P P P Conclusions: Health education with problem-based learning approaches is worth promoting as it can help high-risk pregnant women in plateau areas develop better health knowledge, attitude and practice and healthier coping skills. Also, it can improve patient sanctification.展开更多
Objective:To explore the value of using the venous-arterial carbon dioxide partial pressure difference and the arterial-venous oxygen content difference ratio(ΔP_(CO2)/Ca-v_(O2))as targets to guide early tissue hypop...Objective:To explore the value of using the venous-arterial carbon dioxide partial pressure difference and the arterial-venous oxygen content difference ratio(ΔP_(CO2)/Ca-v_(O2))as targets to guide early tissue hypoperfusion in sepsis in plateau areas.Methods:90 sepsis patients admitted to the Third People’s Hospital of Xining and Golmud People’s Hospital from June 2017 to December 2022 were selected as the research subjects,and they were divided into the Scv_(O2)(central venous oxygen saturation)group and theΔP_(CO2)/Ca-v_(O2)group,with 45 cases in each group.The two groups were treated with early shock resuscitation according to different protocols.The hemodynamic characteristics of the two groups of patients before and after resuscitation were observed,and the volume responsiveness was evaluated.The ROC(receiver operating characteristic)curve was used to analyze the significance ofΔP_(CO2)/Ca-v_(O2),Scv_(O2),lactate,lactate clearance,and urine output in evaluating patient prognosis and the correlation betweenΔP_(CO2)/Ca-v_(O2)and the above indicators was explored.Results:Compared with before resuscitation,after fluid resuscitation,the heart rate(HR),mean arterial pressure(MAP),central venous pressure(CVP),cardiac index(CI),lactate,lactate clearance rate,and urine output of the two groups of patients were significantly improved(P<0.05);in terms of therapeutic effect,the 28-day mortality rate,6-hour fluid balance,and lactic acid clearance of theΔP_(CO2)/Ca-v_(O2)group were better than the Scv_(O2)group.The ROC characteristic curve showed that theΔP_(CO2)/Ca-v_(O2)value can effectively predict the prognosis of patients(AUC=0.907,sensitivity was 97%,specificity was 72.4%,and critical value was 1.84).ΔP_(CO2)/Ca-v_(O2)significantly correlated with Scv_(O2),lactic acid,and lactic acid clearance rate.Conclusion:TheΔP_(CO2)/Ca-v_(O2)value can be used to guide fluid resuscitation in early hypoperfusion in sepsis in plateau areas,improve patients’hemodynamics,reduce lactate indicators,and increase urine output.ΔP_(CO2)/Ca-v_(O2)level>1.84 can effectively improve patient prognosis.展开更多
The applicability of statistics-based landslide susceptibility assessment methods is affected by the number of historical landslides.Previous studies have proposed support vector machine(SVM)as a small-sample learning...The applicability of statistics-based landslide susceptibility assessment methods is affected by the number of historical landslides.Previous studies have proposed support vector machine(SVM)as a small-sample learning method.However,those studies demonstrated that different parameters can affect model performance.We optimized the SVM and obtained models as 5-fold cross validation(5-CV)SVM,genetic algorithm(GA)SVM,and particle swarm optimization(PSO)SVM.This study compared the prediction performances of logistic regression(LR),5-CV SVM,GA SVM,and PSO SVM on landslide susceptibility mapping,to explore the spatial distribution of landslide susceptibility in the study area in Tibetan Plateau,China.A geospatial database was established based on 392 historical landslides and 392 non-landslides in the study area.We used 11 influencing factors of altitude,slope,aspect,curvature,lithology,normalized difference vegetation index(NDVI),distance to road,distance to river,distance to fault,peak ground acceleration(PGA),and rainfall to construct an influencing factor evaluation system.To evaluate the models,four susceptibility maps were compared via receiver operating characteristics(ROC)curve and the results showed that prediction rates for the models are 84%(LR),87%(5-CV SVM),85%(GA SVM),and 90%(PSO SVM).We also used precision,recall,F1-score and accuracy to assess the quality performance of these models.The results showed that the PSO SVM had greater potential for future implementation in the Tibetan Plateau area because of its superior performance in the landslide susceptibility assessment.展开更多
[Objective] The aim was to study on resource utilization of indigenous plants in roads in order to solve resource shortage of indigenous plant in bioengi- neering. [Method] Based on northwestern loess plateau area, we...[Objective] The aim was to study on resource utilization of indigenous plants in roads in order to solve resource shortage of indigenous plant in bioengi- neering. [Method] Based on northwestern loess plateau area, we conducted research on selection of indigenous plants and survey on the species which could live in adverse condition, mainly by surveying, with frequent tests as a supplement, to make a comprehensive observation and evaluation on plant combinations which are to be extensively applied. [Result] The research indicated that in central dividing strips, four arbors, including Platycladus orientalis （Linn.）Franco, Sabina chinensis, Sabinachinen- sis（Linn.）Ant., and Ulmus purnila L., and nine frutices, including Lycium chinense, Tamarix austromongolica, Rosa xanthina Lindl., Forsythia suspense, Atriplex canescens, Amygdalus triloba, Hippophae rharnnoides Linn., Arnorpha fruticosa L., and Syzygium aromaticum could be planted. In addition, Gleditsia sinensis Lain, Robinia pseudoacacia L, Elaeagnus angustifolia L., Rhus typhina, Salix babylonica, Salixmatsudana and Fraxinus chinensis, tall and strong, are suitable to be planted as border trees, presenting a good vision. Frutices, limited by height, are usually with more branches, which will provide a good landscape if grown with tall plants. Prunus dacidiana and Ulmus pumila L., prone to be damaged by insects, should be planted with other species to stop the infestation in space. [Conclusion] The research laid foundation for selection of indigenous plants in roads, providing references for resource shortage of indigenous plant for bioengineedng.展开更多
As turbocharging diesel engines for vehicle application are applied in plateau area, the environmental adaptability of engines has drawn more attention. For the environmental adaptability problem of turbocharging dies...As turbocharging diesel engines for vehicle application are applied in plateau area, the environmental adaptability of engines has drawn more attention. For the environmental adaptability problem of turbocharging diesel engines for vehicle application, the present studies almost focus on the optimization of performance match between turbocharger and engine, and the reliability problem of turbocharger is almost ignored. The reliability problem of compressor impeller of turhocharger for vehicle application when diesel engines operate in plateau area is studied. Firstly, the rule that the rotational speed of turbocharger changes with the altitude height is presented, and the potential failure modes of compressor impeller are analyzed. Then, the failure behavior models of compressor impeller are built, and the reliability models of compressor impeller operating in plateau area are developed. Finally, the rule that the reliability of compressor impeller changes with the altitude height is studied, the measurements for improving the reliability of the compressor impellers of turbocharger operating in plateau area are given. The results indicate that when the operating speed of diesel engine is certain, the rotational speed of turbocharger increases with the increase of altitude height, and the failure risk of compressor impeller with the failure modes of hub fatigue and blade resonance increases. The reliability of compressor impeller decreases with the increase of altitude height, and it also decreases as the increase of number of the mission profile cycle of engine. The method proposed can not only be used to evaluating the reliability of compressor impeller when diesel engines operate in plateau area but also be applied to direct the structural optimization of compressor impeller.展开更多
A comprehensive analysis was conducted on the current situation as well as historic succession processor agriculture and ecological conditions in Northwest China, in particular in the Loess Plateau, by means of a inte...A comprehensive analysis was conducted on the current situation as well as historic succession processor agriculture and ecological conditions in Northwest China, in particular in the Loess Plateau, by means of a inter-disciplinary approach of ecology, agro-geohistory, and agronomy. It was concluded that the fundamental causes responsible for the ecological deterioration, signed by the poor agro-productivity and serious soil erosion, had been the extensive cropping system by ever-increasing reclamation on semi-drought slope land, where initiated a natural vegetation of brushy grasses with sparse trees, thus suitable only for animal husbandry. Based on an identification of specific actual status of China, several countermeasures of correctly dealing with the relationship between agricultural development and the ecological restoration and reconstruction were proposed, including to get breakthrough first in the transection area by means of the rational use of resources and the raising of agro-system productivity, to promoting 'water conservancy-type ecological agriculture' through the radical shift of traditional production pattern, and the adoption of a policy of proper degree of grain self-reliance, as well as to construct livestock industry base in Northwest China.展开更多
This paper presents a study on species diversity and its ecological service function in the plateau area in western Sichuan. The results show that species diversity in the plantations on the cutover land has a tendenc...This paper presents a study on species diversity and its ecological service function in the plateau area in western Sichuan. The results show that species diversity in the plantations on the cutover land has a tendency to increase and that its ecological service function is to be improved with stand age growing. The species diversity in forest communities is also gradually increased on different succession stage till reaching a climax level. But the species diversity in the climax community is slightly decreased before it reaches a relatively constant status. Ecological service function of diversity is gradually strengthened with the progress of succession. In addition, species diversity in a stand in a similar site and at a same age differs among forest types. Species diversity index within a coniferous and broad-leaved mixed forest is larger than that within a coniferous forest. Meanwhile, species diversity enriches as the tree density increases.展开更多
The paper aims to study the impacts and countermeasures of climate change on animal husbandry in Qinghai plateau and its surrounding area,and evaluate the effect of countermeasures.Results showed that：First,the annua...The paper aims to study the impacts and countermeasures of climate change on animal husbandry in Qinghai plateau and its surrounding area,and evaluate the effect of countermeasures.Results showed that：First,the annual mean temperature,annual mean maximum temperature and annual mean minimum temperature showed an increasing trend in Qinghai plateau during the time from 1961 to 2008; the annual precipitation had not obvious change,but the obvious feature of seasonal change; wind speed and sunshine hours showed a decreasing trend during the time from 1961 to 2008.Secondly,under the current climate condition,grassland productivity showed a decreasing trend,and the grassland theoretical capacity affected by grassland productivity decreased too; warm winter was in favor of livestock overwintering safely,which resulted in a high level of the survival rate of young stock; temperature increasing and precipitation decreasing were beneficial to the fatness of livestock,but the meat yield of livestock was affected by some negative factors such as grassland degradation; livestock diseases had a close relationship with weather condition,and adverse weather condition may arose many diseases of livestock.Thirdly,in view of the current problems of livestock production,we took a series of countermeasures including grass industry construction,livestock improvement,developing new modes of animal husbandry,control and prevention of stockbreeding diseases and insect pests and recovery of meteorological disasters,which played a important role in promoting grassland productivity,solving the problem of the imbalances between livestock and forage,protecting the ecological environment and improving livestock performance.展开更多
The study area lies in the Dadu River drainage area in upstream Yangtze River.The spatial distribution of subalpine coniferous forests in 1989 and 2009 was extracted by means of a combined method of object orientation...The study area lies in the Dadu River drainage area in upstream Yangtze River.The spatial distribution of subalpine coniferous forests in 1989 and 2009 was extracted by means of a combined method of object orientation and visual interpretation,and then the overlaying analysis of these data was conducted.The type and spatial location of succession were discovered and served as the sample of dependant variable.Meanwhile,supported by GIS technology and based on DEM and thematic data,the eight variables including altitude,slope,sin and cosin of aspect,curvity of land surface,and distance to residential area,cultivated land and road were extracted served as the sample of spatial succession of subalpine coniferous forests to fit Logistic Regression,and then the contribution of each independent variable as well as the spatial property of the occurrence probability of succession was calculated.The results suggested that,during the succession of subalpine coniferous forests to meadow,the closer to the residential area and cultivated land,the greater the contribution to succession is.In particular,when the distance to the residential area decreases by one unit,the probability for its conversion to meadow will be increased by 1.15 times.During the succession of subalpine coniferous forests to deciduous-broadleaved shrubs,the sin of aspect and distance to residential area contribute more,and the probability of succession increases with increasing degree of northwardness,i.e.when the degree of northwardness increases by one unit,the probability will be increased by 1.2 times.The quantitative analysis of spatial succession property of subalpine coniferous forests will supply scientific basis to the protection and restoration of subalpine coniferous forests.展开更多
Based on the investigation and analysis of characteristics of precipitation, natural environment, socio-economic factors and soil erosion, this paper indicates that the precipitation is the main driving force for the ...Based on the investigation and analysis of characteristics of precipitation, natural environment, socio-economic factors and soil erosion, this paper indicates that the precipitation is the main driving force for the soil erosion in the sediment-rich area, its variability determines the characteristics of soil and water loss; the natural conditions such as the drainage systems, geological and topographic features, the composition of soil and land surface materials, vegetation and climate determine the seriousness of soil and water loss; irrational socio-economic activities of human beings usually accelerated soil and water loss; meanwhile, the low preservation rate and inferiority of soil and water conservation measures made it impossible to make rapid progress on soil and water loss control. Furthermore, the characteristics of erosion environment endowed this area with more sediment that is the main reason for the flooding disasters by the Yellow River. Therefore, more emphasis should be placed on the enhancement of soil and water conservation. The soil loss prediction models will provide scientific basis for the planning of soil and water conservation, the designing of soil and water conservation measures and the valuation of effects of soil and water loss control. According to the analysis of the previous studies on soil loss prediction, and the water-sediment variation features, it is thought that study on soil loss prediction under various rainfall conditions and soil-water conservation measures should be carried out.展开更多
With the rapid development of social economy and urban−rural integration,the phenomenon of farmland aban-donment worldwide has proved to be one of the main trends of land use and land cover change(LUCC),and profoundly...With the rapid development of social economy and urban−rural integration,the phenomenon of farmland aban-donment worldwide has proved to be one of the main trends of land use and land cover change(LUCC),and profoundly affected the rural landscape and regional ecological environment.Restricted by the natural environ-ment,economic development and backward agricultural technology,the phenomenon of farmland abandonment is also common in the Qingzang Plateau(QP).Therefore,this paper adopted the spatial autocorrelation method to analyze the spatial pattern of abandonment in the agricultural and pastoral areas of the Qingzang Plateau(APA−QP)in 2017,and the geographically weighted regression(GWR)model to explore the effects of geograph-ical resources,socio-economic development and location conditions on farmland abandonment.This study found that:1)From 2015 to 2017,the abandoned farmland area in the APA−QP was approximately 18.23×10^(4)ha,with an overall abandonment rate of 15.18%.On the whole,it showed the distribution characteristics of“strong in the south and weak in the north,strong in the east and weak in the west”.2)There were positive spatial correlation between both abandoned area and abandonment rate in the APA−QP,showing“concave”and“convex”patterns,respectively,mainly concentrated in the Huang−shui Valley and the Southeast Tibet;while in the western and northern regions,the degree of abandonment was relatively low.3)Farmland abandonment in the APA−QP was mainly driven by the geographical environment changes and farmers’decision−making on farmland utilization.There was significant spatial heterogeneity on farmland abandonment associated with the impact of geographical resources,socio−economics and location conditions.The geographical resource factors had a positive impact on the abandonment,and were strongly constrained by natural geographic conditions such as altitude and slope.The farmland resources in the Qingzang Plateau are limited,but are of strategic significance for the sustainable development of agriculture in the whole Qingzang Plateau.In order to realize the rational distribution of agricul-ture and animal husbandry and the sustainable utilization of farmland resources in the plateau region,land use strategies should be implemented according to regional differences and regional advantages in order to ensure the ecological environment security of Qingzang Plateau.展开更多
On the basis of main contents of social construction and key points of construction,this paper analyzes features of conditions of northwest Sichuan plateau pastoral area.The social construction at current stage mainly...On the basis of main contents of social construction and key points of construction,this paper analyzes features of conditions of northwest Sichuan plateau pastoral area.The social construction at current stage mainly includes social cause in narrow sense,and social management at meso-level.The northwest Sichuan plateau pastoral area is faced with the best policy and development opportunity.However,there are still many weak aspects.Firstly,social structure is not coordinated with economic structure.Secondly,social construction ability of grass-roots government is weak.Thirdly,the ability to respond to public demands is low.Fourthly,there is a big gap in availability of basic public service.Finally,it presents path selection for social construction of northwest Sichuan plateau pastoral area:strengthen social construction ability of grass-roots government;promote social construction with livelihood projects as key projects;boost social construction taking advantage of ecological construction;develop basic public service with the aid of external forces;intensify evaluation system for supervision of social construction works.展开更多
Spodoptera frugiperda (J.E.Smmith) is one of the major migratory pests warned by the Food and Agriculture Organization (FAO).It has been successfully invaded sugarcane and corn in Jinggu,Longchuan,Gengma,Menghai,Yingj...Spodoptera frugiperda (J.E.Smmith) is one of the major migratory pests warned by the Food and Agriculture Organization (FAO).It has been successfully invaded sugarcane and corn in Jinggu,Longchuan,Gengma,Menghai,Yingjiang,Lancang of Yunan Province,China.In view of the great variety of hosts,wide range of habitats and strong migration ability,S.frugiperda has the potential of causing catastrophic threats to sugarcane production.In this paper,we made a systematic introduction to the morphological and biological characteristics of S.frugiperda,analyzed its occurrence situations and occurrence trends in Yunnan of China and other countries around the world,and proposed the control strategies and measures of ecological regulation and control,natural enemies protection and utilization,biological control,pesticide control and adults trapping based on the outbreak characteristics of S.frugiperda and the actual sugarcane production in low latitude plateau areas.展开更多
Objective The Cenozoic Indo-Asian collision caused significant crustal shortening and plateau uplift in the central Tibet. The extrusion tectonic model has been widely accepted to explain the strike-slip faults around...Objective The Cenozoic Indo-Asian collision caused significant crustal shortening and plateau uplift in the central Tibet. The extrusion tectonic model has been widely accepted to explain the strike-slip faults around the Tibetan Plateau. Previous studies indicate that the lower crust flow is the main drive force of the extrusion tectonics. Whether mantle extrusion process occurred during the Cenozoic uplift is a major problem to be addressed, which is significant for understanding the uplift mechanism and tectonic evolution of the Tibetan Plateau.展开更多
Aortic dissection is the deadliest disease of the cardiovascular system.Type B aortic dissection accounts for 30%-60%of aortic dissections and is mainly treated by endovascular repair of thoracic endovascular aneurysm...Aortic dissection is the deadliest disease of the cardiovascular system.Type B aortic dissection accounts for 30%-60%of aortic dissections and is mainly treated by endovascular repair of thoracic endovascular aneurysm repair(TEVAR).However,patients are prone to various complications after surgery,with central nervous system injury being the most common,which seriously affects their prognosis and increases the risk of disability and death.Therefore,exploring the risk factors of central nervous system injury after TEVAR can provide a basis for its prevention and control.AIM To investigate the risk factors for central nervous system injury after the repair of a thoracic endovascular aneurysm with type B aortic dissection.METHODS We enrolled 306 patients with type B aortic dissection who underwent TEVAR at our hospital between December 2019 and October 2022.The patients were categorized into injury(n=159)and non-injury(n=147)groups based on central nervous system injury following surgery.The risk factors for central nervous system injury after TEVAR for type B aortic dissection were screened by comparing the two groups.Multivariate logistic regression analysis was performed.RESULTS The Association between age,history of hypertension,blood pH value,surgery,mechanical ventilation,intensive care unit stay,postoperative recovery times on the first day after surgery,and arterial partial pressure of oxygen on the first day after surgery differed substantially(P<0.05).Multivariate logistic regression analysis indicated that age,surgery time,history of hypertension,duration of mechanical ventilation,and intensive care unit stay were independent risk factors for central nervous system injury after TEVAR of type B aortic dissection(P<0.05).CONCLUSION For high-risk patients with central nervous system injury after TEVAR of type B aortic dissection,early intervention measures should be implemented to lower the risk of neurological discomfort following surgery in high-risk patients with central nervous system injury after TEVAR for type B aortic dissection.展开更多
文摘Objective: Given the unique cultural background, way of life, and physical environment of the Tibetan Plateau, this study aims to investigate the effects of health education using problem-based learning (PBL) approaches on the knowledge, attitude, practice, and coping skills of women with high-risk pregnancies in this region. Methods: 76 high-risk pregnancy cases were enrolled at Tibet’s Linzhi People’s Hospital between September 2023 and April 2024. 30 patients admitted between September 2023 and December 2023 were selected as the control group and were performed with regular patient education. 46 patients admitted between January 2024 and April 2024 were selected as the observation group and were performed regular patient education with problem-based learning approaches. Two groups’ performance on their health knowledge, attitude, practice and coping skills before and after interventions were evaluated, and patient satisfaction were measured at the end of the study. Results: There was no statistical significance (P P P Conclusions: Health education with problem-based learning approaches is worth promoting as it can help high-risk pregnant women in plateau areas develop better health knowledge, attitude and practice and healthier coping skills. Also, it can improve patient sanctification.
基金2017 Xining Citizens’Biotechnology Plan Project(Project number:2017-K-15)。
文摘Objective:To explore the value of using the venous-arterial carbon dioxide partial pressure difference and the arterial-venous oxygen content difference ratio(ΔP_(CO2)/Ca-v_(O2))as targets to guide early tissue hypoperfusion in sepsis in plateau areas.Methods:90 sepsis patients admitted to the Third People’s Hospital of Xining and Golmud People’s Hospital from June 2017 to December 2022 were selected as the research subjects,and they were divided into the Scv_(O2)(central venous oxygen saturation)group and theΔP_(CO2)/Ca-v_(O2)group,with 45 cases in each group.The two groups were treated with early shock resuscitation according to different protocols.The hemodynamic characteristics of the two groups of patients before and after resuscitation were observed,and the volume responsiveness was evaluated.The ROC(receiver operating characteristic)curve was used to analyze the significance ofΔP_(CO2)/Ca-v_(O2),Scv_(O2),lactate,lactate clearance,and urine output in evaluating patient prognosis and the correlation betweenΔP_(CO2)/Ca-v_(O2)and the above indicators was explored.Results:Compared with before resuscitation,after fluid resuscitation,the heart rate(HR),mean arterial pressure(MAP),central venous pressure(CVP),cardiac index(CI),lactate,lactate clearance rate,and urine output of the two groups of patients were significantly improved(P<0.05);in terms of therapeutic effect,the 28-day mortality rate,6-hour fluid balance,and lactic acid clearance of theΔP_(CO2)/Ca-v_(O2)group were better than the Scv_(O2)group.The ROC characteristic curve showed that theΔP_(CO2)/Ca-v_(O2)value can effectively predict the prognosis of patients(AUC=0.907,sensitivity was 97%,specificity was 72.4%,and critical value was 1.84).ΔP_(CO2)/Ca-v_(O2)significantly correlated with Scv_(O2),lactic acid,and lactic acid clearance rate.Conclusion:TheΔP_(CO2)/Ca-v_(O2)value can be used to guide fluid resuscitation in early hypoperfusion in sepsis in plateau areas,improve patients’hemodynamics,reduce lactate indicators,and increase urine output.ΔP_(CO2)/Ca-v_(O2)level>1.84 can effectively improve patient prognosis.
基金financially supported by the National Natural Science Foundation of China(41977213)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0906)+3 种基金Science and Technology Department of Sichuan Province(2021YJ0032)Sichuan Transportation Science and Technology Project(2021-A-03)Sichuan Science and Technology Program(2022NSFSC0425)CREC Sichuan Eco-City Investment Co,Ltd.(R110121H01092)。
文摘The applicability of statistics-based landslide susceptibility assessment methods is affected by the number of historical landslides.Previous studies have proposed support vector machine(SVM)as a small-sample learning method.However,those studies demonstrated that different parameters can affect model performance.We optimized the SVM and obtained models as 5-fold cross validation(5-CV)SVM,genetic algorithm(GA)SVM,and particle swarm optimization(PSO)SVM.This study compared the prediction performances of logistic regression(LR),5-CV SVM,GA SVM,and PSO SVM on landslide susceptibility mapping,to explore the spatial distribution of landslide susceptibility in the study area in Tibetan Plateau,China.A geospatial database was established based on 392 historical landslides and 392 non-landslides in the study area.We used 11 influencing factors of altitude,slope,aspect,curvature,lithology,normalized difference vegetation index(NDVI),distance to road,distance to river,distance to fault,peak ground acceleration(PGA),and rainfall to construct an influencing factor evaluation system.To evaluate the models,four susceptibility maps were compared via receiver operating characteristics(ROC)curve and the results showed that prediction rates for the models are 84%(LR),87%(5-CV SVM),85%(GA SVM),and 90%(PSO SVM).We also used precision,recall,F1-score and accuracy to assess the quality performance of these models.The results showed that the PSO SVM had greater potential for future implementation in the Tibetan Plateau area because of its superior performance in the landslide susceptibility assessment.
文摘[Objective] The aim was to study on resource utilization of indigenous plants in roads in order to solve resource shortage of indigenous plant in bioengi- neering. [Method] Based on northwestern loess plateau area, we conducted research on selection of indigenous plants and survey on the species which could live in adverse condition, mainly by surveying, with frequent tests as a supplement, to make a comprehensive observation and evaluation on plant combinations which are to be extensively applied. [Result] The research indicated that in central dividing strips, four arbors, including Platycladus orientalis （Linn.）Franco, Sabina chinensis, Sabinachinen- sis（Linn.）Ant., and Ulmus purnila L., and nine frutices, including Lycium chinense, Tamarix austromongolica, Rosa xanthina Lindl., Forsythia suspense, Atriplex canescens, Amygdalus triloba, Hippophae rharnnoides Linn., Arnorpha fruticosa L., and Syzygium aromaticum could be planted. In addition, Gleditsia sinensis Lain, Robinia pseudoacacia L, Elaeagnus angustifolia L., Rhus typhina, Salix babylonica, Salixmatsudana and Fraxinus chinensis, tall and strong, are suitable to be planted as border trees, presenting a good vision. Frutices, limited by height, are usually with more branches, which will provide a good landscape if grown with tall plants. Prunus dacidiana and Ulmus pumila L., prone to be damaged by insects, should be planted with other species to stop the infestation in space. [Conclusion] The research laid foundation for selection of indigenous plants in roads, providing references for resource shortage of indigenous plant for bioengineedng.
基金Supported by National Natural Science Foundation of Chin(Grant No.51375465)
文摘As turbocharging diesel engines for vehicle application are applied in plateau area, the environmental adaptability of engines has drawn more attention. For the environmental adaptability problem of turbocharging diesel engines for vehicle application, the present studies almost focus on the optimization of performance match between turbocharger and engine, and the reliability problem of turbocharger is almost ignored. The reliability problem of compressor impeller of turhocharger for vehicle application when diesel engines operate in plateau area is studied. Firstly, the rule that the rotational speed of turbocharger changes with the altitude height is presented, and the potential failure modes of compressor impeller are analyzed. Then, the failure behavior models of compressor impeller are built, and the reliability models of compressor impeller operating in plateau area are developed. Finally, the rule that the reliability of compressor impeller changes with the altitude height is studied, the measurements for improving the reliability of the compressor impellers of turbocharger operating in plateau area are given. The results indicate that when the operating speed of diesel engine is certain, the rotational speed of turbocharger increases with the increase of altitude height, and the failure risk of compressor impeller with the failure modes of hub fatigue and blade resonance increases. The reliability of compressor impeller decreases with the increase of altitude height, and it also decreases as the increase of number of the mission profile cycle of engine. The method proposed can not only be used to evaluating the reliability of compressor impeller when diesel engines operate in plateau area but also be applied to direct the structural optimization of compressor impeller.
基金the Chinese Ministry of Science and Technology(No.2000018600).
文摘A comprehensive analysis was conducted on the current situation as well as historic succession processor agriculture and ecological conditions in Northwest China, in particular in the Loess Plateau, by means of a inter-disciplinary approach of ecology, agro-geohistory, and agronomy. It was concluded that the fundamental causes responsible for the ecological deterioration, signed by the poor agro-productivity and serious soil erosion, had been the extensive cropping system by ever-increasing reclamation on semi-drought slope land, where initiated a natural vegetation of brushy grasses with sparse trees, thus suitable only for animal husbandry. Based on an identification of specific actual status of China, several countermeasures of correctly dealing with the relationship between agricultural development and the ecological restoration and reconstruction were proposed, including to get breakthrough first in the transection area by means of the rational use of resources and the raising of agro-system productivity, to promoting 'water conservancy-type ecological agriculture' through the radical shift of traditional production pattern, and the adoption of a policy of proper degree of grain self-reliance, as well as to construct livestock industry base in Northwest China.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Scicnces(KZCX2-SW-319-4)
文摘This paper presents a study on species diversity and its ecological service function in the plateau area in western Sichuan. The results show that species diversity in the plantations on the cutover land has a tendency to increase and that its ecological service function is to be improved with stand age growing. The species diversity in forest communities is also gradually increased on different succession stage till reaching a climax level. But the species diversity in the climax community is slightly decreased before it reaches a relatively constant status. Ecological service function of diversity is gradually strengthened with the progress of succession. In addition, species diversity in a stand in a similar site and at a same age differs among forest types. Species diversity index within a coniferous and broad-leaved mixed forest is larger than that within a coniferous forest. Meanwhile, species diversity enriches as the tree density increases.
文摘The paper aims to study the impacts and countermeasures of climate change on animal husbandry in Qinghai plateau and its surrounding area,and evaluate the effect of countermeasures.Results showed that：First,the annual mean temperature,annual mean maximum temperature and annual mean minimum temperature showed an increasing trend in Qinghai plateau during the time from 1961 to 2008; the annual precipitation had not obvious change,but the obvious feature of seasonal change; wind speed and sunshine hours showed a decreasing trend during the time from 1961 to 2008.Secondly,under the current climate condition,grassland productivity showed a decreasing trend,and the grassland theoretical capacity affected by grassland productivity decreased too; warm winter was in favor of livestock overwintering safely,which resulted in a high level of the survival rate of young stock; temperature increasing and precipitation decreasing were beneficial to the fatness of livestock,but the meat yield of livestock was affected by some negative factors such as grassland degradation; livestock diseases had a close relationship with weather condition,and adverse weather condition may arose many diseases of livestock.Thirdly,in view of the current problems of livestock production,we took a series of countermeasures including grass industry construction,livestock improvement,developing new modes of animal husbandry,control and prevention of stockbreeding diseases and insect pests and recovery of meteorological disasters,which played a important role in promoting grassland productivity,solving the problem of the imbalances between livestock and forage,protecting the ecological environment and improving livestock performance.
基金Supported by National Natural Science Foundation of China(40901057)Key Project of Chinese National Programs for Fundamental Research and Development(2010CB951704)~~
文摘The study area lies in the Dadu River drainage area in upstream Yangtze River.The spatial distribution of subalpine coniferous forests in 1989 and 2009 was extracted by means of a combined method of object orientation and visual interpretation,and then the overlaying analysis of these data was conducted.The type and spatial location of succession were discovered and served as the sample of dependant variable.Meanwhile,supported by GIS technology and based on DEM and thematic data,the eight variables including altitude,slope,sin and cosin of aspect,curvity of land surface,and distance to residential area,cultivated land and road were extracted served as the sample of spatial succession of subalpine coniferous forests to fit Logistic Regression,and then the contribution of each independent variable as well as the spatial property of the occurrence probability of succession was calculated.The results suggested that,during the succession of subalpine coniferous forests to meadow,the closer to the residential area and cultivated land,the greater the contribution to succession is.In particular,when the distance to the residential area decreases by one unit,the probability for its conversion to meadow will be increased by 1.15 times.During the succession of subalpine coniferous forests to deciduous-broadleaved shrubs,the sin of aspect and distance to residential area contribute more,and the probability of succession increases with increasing degree of northwardness,i.e.when the degree of northwardness increases by one unit,the probability will be increased by 1.2 times.The quantitative analysis of spatial succession property of subalpine coniferous forests will supply scientific basis to the protection and restoration of subalpine coniferous forests.
基金Knowledge Innovation Project of CAS, No. KZCX1-10-04
文摘Based on the investigation and analysis of characteristics of precipitation, natural environment, socio-economic factors and soil erosion, this paper indicates that the precipitation is the main driving force for the soil erosion in the sediment-rich area, its variability determines the characteristics of soil and water loss; the natural conditions such as the drainage systems, geological and topographic features, the composition of soil and land surface materials, vegetation and climate determine the seriousness of soil and water loss; irrational socio-economic activities of human beings usually accelerated soil and water loss; meanwhile, the low preservation rate and inferiority of soil and water conservation measures made it impossible to make rapid progress on soil and water loss control. Furthermore, the characteristics of erosion environment endowed this area with more sediment that is the main reason for the flooding disasters by the Yellow River. Therefore, more emphasis should be placed on the enhancement of soil and water conservation. The soil loss prediction models will provide scientific basis for the planning of soil and water conservation, the designing of soil and water conservation measures and the valuation of effects of soil and water loss control. According to the analysis of the previous studies on soil loss prediction, and the water-sediment variation features, it is thought that study on soil loss prediction under various rainfall conditions and soil-water conservation measures should be carried out.
基金This research was supported by the National Social Science Fund of China(Grant No.20&ZD090)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0405)the Na-tional Natural Science Foundation of China(Grant No.42071249,Grant No.42001199).
文摘With the rapid development of social economy and urban−rural integration,the phenomenon of farmland aban-donment worldwide has proved to be one of the main trends of land use and land cover change(LUCC),and profoundly affected the rural landscape and regional ecological environment.Restricted by the natural environ-ment,economic development and backward agricultural technology,the phenomenon of farmland abandonment is also common in the Qingzang Plateau(QP).Therefore,this paper adopted the spatial autocorrelation method to analyze the spatial pattern of abandonment in the agricultural and pastoral areas of the Qingzang Plateau(APA−QP)in 2017,and the geographically weighted regression(GWR)model to explore the effects of geograph-ical resources,socio-economic development and location conditions on farmland abandonment.This study found that:1)From 2015 to 2017,the abandoned farmland area in the APA−QP was approximately 18.23×10^(4)ha,with an overall abandonment rate of 15.18%.On the whole,it showed the distribution characteristics of“strong in the south and weak in the north,strong in the east and weak in the west”.2)There were positive spatial correlation between both abandoned area and abandonment rate in the APA−QP,showing“concave”and“convex”patterns,respectively,mainly concentrated in the Huang−shui Valley and the Southeast Tibet;while in the western and northern regions,the degree of abandonment was relatively low.3)Farmland abandonment in the APA−QP was mainly driven by the geographical environment changes and farmers’decision−making on farmland utilization.There was significant spatial heterogeneity on farmland abandonment associated with the impact of geographical resources,socio−economics and location conditions.The geographical resource factors had a positive impact on the abandonment,and were strongly constrained by natural geographic conditions such as altitude and slope.The farmland resources in the Qingzang Plateau are limited,but are of strategic significance for the sustainable development of agriculture in the whole Qingzang Plateau.In order to realize the rational distribution of agricul-ture and animal husbandry and the sustainable utilization of farmland resources in the plateau region,land use strategies should be implemented according to regional differences and regional advantages in order to ensure the ecological environment security of Qingzang Plateau.
基金Supported by the Ford Foundation " Policy Research on Development of Plateau Pastoral Areas at Upstream Yangtze River"(1095-0787)
文摘On the basis of main contents of social construction and key points of construction,this paper analyzes features of conditions of northwest Sichuan plateau pastoral area.The social construction at current stage mainly includes social cause in narrow sense,and social management at meso-level.The northwest Sichuan plateau pastoral area is faced with the best policy and development opportunity.However,there are still many weak aspects.Firstly,social structure is not coordinated with economic structure.Secondly,social construction ability of grass-roots government is weak.Thirdly,the ability to respond to public demands is low.Fourthly,there is a big gap in availability of basic public service.Finally,it presents path selection for social construction of northwest Sichuan plateau pastoral area:strengthen social construction ability of grass-roots government;promote social construction with livelihood projects as key projects;boost social construction taking advantage of ecological construction;develop basic public service with the aid of external forces;intensify evaluation system for supervision of social construction works.
基金Supported by the Sugar Crop Research System(CARS-170303)the Training Project of Yunling Industry and Technology Leading Talents(2018LJRC56)the Special Fund of Agricultural Industry Research System in Yunnan Province
文摘Spodoptera frugiperda (J.E.Smmith) is one of the major migratory pests warned by the Food and Agriculture Organization (FAO).It has been successfully invaded sugarcane and corn in Jinggu,Longchuan,Gengma,Menghai,Yingjiang,Lancang of Yunan Province,China.In view of the great variety of hosts,wide range of habitats and strong migration ability,S.frugiperda has the potential of causing catastrophic threats to sugarcane production.In this paper,we made a systematic introduction to the morphological and biological characteristics of S.frugiperda,analyzed its occurrence situations and occurrence trends in Yunnan of China and other countries around the world,and proposed the control strategies and measures of ecological regulation and control,natural enemies protection and utilization,biological control,pesticide control and adults trapping based on the outbreak characteristics of S.frugiperda and the actual sugarcane production in low latitude plateau areas.
基金supported by the National Natural Science Foundation of China (grant No.41072052)
文摘Objective The Cenozoic Indo-Asian collision caused significant crustal shortening and plateau uplift in the central Tibet. The extrusion tectonic model has been widely accepted to explain the strike-slip faults around the Tibetan Plateau. Previous studies indicate that the lower crust flow is the main drive force of the extrusion tectonics. Whether mantle extrusion process occurred during the Cenozoic uplift is a major problem to be addressed, which is significant for understanding the uplift mechanism and tectonic evolution of the Tibetan Plateau.
文摘Aortic dissection is the deadliest disease of the cardiovascular system.Type B aortic dissection accounts for 30%-60%of aortic dissections and is mainly treated by endovascular repair of thoracic endovascular aneurysm repair(TEVAR).However,patients are prone to various complications after surgery,with central nervous system injury being the most common,which seriously affects their prognosis and increases the risk of disability and death.Therefore,exploring the risk factors of central nervous system injury after TEVAR can provide a basis for its prevention and control.AIM To investigate the risk factors for central nervous system injury after the repair of a thoracic endovascular aneurysm with type B aortic dissection.METHODS We enrolled 306 patients with type B aortic dissection who underwent TEVAR at our hospital between December 2019 and October 2022.The patients were categorized into injury(n=159)and non-injury(n=147)groups based on central nervous system injury following surgery.The risk factors for central nervous system injury after TEVAR for type B aortic dissection were screened by comparing the two groups.Multivariate logistic regression analysis was performed.RESULTS The Association between age,history of hypertension,blood pH value,surgery,mechanical ventilation,intensive care unit stay,postoperative recovery times on the first day after surgery,and arterial partial pressure of oxygen on the first day after surgery differed substantially(P<0.05).Multivariate logistic regression analysis indicated that age,surgery time,history of hypertension,duration of mechanical ventilation,and intensive care unit stay were independent risk factors for central nervous system injury after TEVAR of type B aortic dissection(P<0.05).CONCLUSION For high-risk patients with central nervous system injury after TEVAR of type B aortic dissection,early intervention measures should be implemented to lower the risk of neurological discomfort following surgery in high-risk patients with central nervous system injury after TEVAR for type B aortic dissection.
