Through the field survey, previous researches and interpretation of aerial photos, a landslide information database of Xiaojiang Valley, Yunnan Province was set up based on the remote sensing (RS) and geographic infor...Through the field survey, previous researches and interpretation of aerial photos, a landslide information database of Xiaojiang Valley, Yunnan Province was set up based on the remote sensing (RS) and geographic information system (GIS) technologies. In the paper, a quantitative model for the landslide hazard assessment and zoning was presented, in which the potential energy could be obtained on basis of thorough analysis of the potential sliding volume, distance and direction of the landslide body. Taking landslide potential energy as the index of the hazard severity zonation, the study area was divided into severe, heavy, medium and light hazard zones.展开更多
Developing effective strategies to prevent diarrhea and associated-gut disorders in mammals has gained great significance.Owing to the many health benefits provided by the commensal microbiota of the intestinal tract,...Developing effective strategies to prevent diarrhea and associated-gut disorders in mammals has gained great significance.Owing to the many health benefits provided by the commensal microbiota of the intestinal tract,such as against environmental perturbation,we explored the host phenotype-associated microbes and their probiotic potential.Based on the observations that the chronic heat stress-exposed weaned piglets present as heat stress-susceptible(HS-SUS)or heat stress-resistant(HS-RES)individuals,we confirmed the phenotypic difference between the two on growth performance(P<0.05),diarrhea index(P<0.001),intestinal heat shock protein 70(HSP70)regulation(P<0.01),and inflammatory responses(P<0.01).By comparing the gut microbiome using 16S rRNA gene sequencing and KEGG functional analysis,we found that Lactobacillus johnsonii exhibited significantly higher relative abundance in the HS-RES piglets than in the HS-SUS ones(P<0.05).Further experiments using a mouse model for chemical-induced inflammation and intestinal injury demonstrated that oral administration of a representative L.johnsonii N5(isolated from the HS-RES piglets)ameliorated the clinical and histological signs of colitis while suppressing intestinal pro-inflammatory cytokines TNF-a and IL-6 production(P<0.05).We found that N5 treatment enhanced tight junction proteins ZO-1 and occludin and cytoprotective HSP70 levels under physiological condition and restored their mucosal expressions in colitis(P<0.05).In support of the high production of the anti-inflammatory cytokine IL-10,N5 promoted the intestinal Peyer’s patches MHCⅡ+and CD103+dendritic cell populations(P<0.05),increased the regulatory T(Treg)cell numbers(P<0.05),and decreased the Th17 population and its IL-17a production under physiological condition and during colitis(P<0.01).Our results shed light on understanding the interaction between commensal Lactobacillus and the host health,and provide L.johnsonii N5 as an alternative to antibiotics for preventing diarrhea and intestinal diseases.展开更多
Tibet is located at the southwest boundary of China. It is the main body of the Qinghai-Tibet Plateau, the highest and the youngest plateau in the world. Owing to complicated geology, Neo-tectonic movements, geomorpho...Tibet is located at the southwest boundary of China. It is the main body of the Qinghai-Tibet Plateau, the highest and the youngest plateau in the world. Owing to complicated geology, Neo-tectonic movements, geomorphology, climate and plateau environment, various mountain hazards, such as debris flow, flash flood, landslide, collapse, snow avalanche and snow drifts, are widely distributed along the Jinsha River (the upper reaches of the Yangtze River), the Nu River and the Lancang River in the east, and the Yarlungzangbo River, the Pumqu River and the Poiqu River in the south and southeast of Tibet. The distribution area of mountain hazards in Tibet is about 589,000 km2, 49.3% of its total territory. In comparison to other mountain regions in China, mountain hazards in Tibet break out unexpectedly with tremendously large scale and endanger the traffic lines, cities and towns, farmland, grassland, mountain environment, and make more dangers to the neighboring countries, such as Nepal, India, Myanmar and Bhutan. To mitigate mountain hazards, some suggestions are proposed in this paper, such as strengthening scientific research, enhancing joint studies, hazards mitigation planning, hazards warning and forecasting, controlling the most disastrous hazards and forbidding unreasonable human exploring activities in mountain areas.展开更多
To reveal the gravitational erosion process in the headstream area of Jiangjia Ravine, continuous observation was conduced duing the rainy season. The observation and research show that the change of water content of ...To reveal the gravitational erosion process in the headstream area of Jiangjia Ravine, continuous observation was conduced duing the rainy season. The observation and research show that the change of water content of the bank slope lags the precipitation process, the infiltration water concentrates mainly in the shallow layer of the bank slope, also the bank slope was unsaturated, the floods and debris flows in the gully down cut the gully bed, and scour the foot of the bank slope. These results in many collapses, which is the main type of gravitational erosion process, and it provides large amounts of loose solid materials for the eruption of debris flows.展开更多
The development of urbanization has led to an increase in the number and scale of construction projects and the types of building construction engineering are getting advance and diverse due to the rapid development o...The development of urbanization has led to an increase in the number and scale of construction projects and the types of building construction engineering are getting advance and diverse due to the rapid development of technology.One of them is the static pressure prestressed pipe pile which is the most commonly used technology in modern building construction work.It is mainly used for pile foundation in construction work,and it has the advantages in less pollution,low noise,and high efficiency compared to the traditional pile foundation.Study on the characteristics of static pressure prestressed pipe pile must be carried out and strengthened the research to increase the effectiveness and quality of static pressure prestressed pipe pile on construction works.This paper is mainly to analyzed the characteristic and construction technology of static pressure prestressed pipe piles on building construction work.展开更多
Floodwater and debris flow caused by glacial lake burst is an important land process and a serious mountain disaster in glacial area of Xizang (Tibet) Autonomous Region, and the overflow burst is mainly caused by glac...Floodwater and debris flow caused by glacial lake burst is an important land process and a serious mountain disaster in glacial area of Xizang (Tibet) Autonomous Region, and the overflow burst is mainly caused by glacial landslide falling into moraine lake. On the premise that moraine lake is full, instantaneous burst in part of the lake bank happens, as flow velocity at burst mouth caused by overflow head is higher than threshold flow velocity of glacial till. Under some supposes, d(90) and d(10) of the glacial till in the hank were used as the threshold sizes of coarse and fine grains respectively. Thus, the formula of calculating threshold flow velocity of uniform sand was simplified, and threshold flow velocity of glacial till was calculated with the formula. Then, with synthesis formula calculating flow velocity of instantaneous part burst, flow velocity at overflow burst mouth was calculated, and calculation formula of critical height (H(0)) of overflow head was derived. Overflow head was caused by volume and surge of glacial landslide falling into moraine lake, calculation formulas of ascendant height (H(1)) of lake water surface and surge height (H(2)) on burst mouth caused by glacial landslide falling into moraine lake were derived. To sum up, critical hydrologic conditions of moraine lake burst with overflow form are: the burst is inevitable as H(1) > H(0); the burst is possible as H(1) < H(0) and (H(1)+H(2)) > H(0); the burst is impossible as (H(1)+H(2)) < H(0). In the factors influencing the burst critical conditions, it is advantageous for the burst that scale of the lake is 10(5)m(2) range; terminal glacial till is more fine and is even more uniform; the width of overflow mouth is even smaller than the length of the bank; the landslide has large scale and steep slip surface; and glacial end is close to the lake. With burst of Guangxiecuo Lake in Midui Valley of the Polongzangbu River in Xizang as an example, the burst critical conditions were tested.展开更多
Debris flow is one of the most destructive phenomena of natural hazards. Recently, major natural hazard, claiming human lives and assets, is due to debris flow in the world. Several practical methods for forecasting d...Debris flow is one of the most destructive phenomena of natural hazards. Recently, major natural hazard, claiming human lives and assets, is due to debris flow in the world. Several practical methods for forecasting debris flow have been proposed, however, the accuracy of these methods is not high enough for practical use because of the stochastic and non-linear characteristics of debris flow. Artificial neural network has proven to be feasible and useful in developing models for nonlinear systems. On the other hand, predicting the future behavior based on a time series of collected historical data is also an important tool in many scientific applications. In this study we present a three-layer feed-forward neural network model to forecast surge of debris flow according to the time series data collected in the Jiangjia Ravine, situated in north part of Yunnan Province of China. The simulation and prediction of debris flow using the proposed approach shows this model is feasible, however, further studies are needed.展开更多
Based on four kinds of methods—numerical weather prediction model, cloud image of stationary meteorological satellite, echo image of meteorological radar and telemetric rain gauge, multi space-time scale precipitatio...Based on four kinds of methods—numerical weather prediction model, cloud image of stationary meteorological satellite, echo image of meteorological radar and telemetric rain gauge, multi space-time scale precipitation prediction products have been achieved, and multi-layer project of debris flow forecast is established with different space-time scale to get different forecast precision. The forecast system has the advantages in combination of regions and ravines, rational compounding of time and space scale. The project, which has debris flow forecast models of Sichuan province, Liangshan district and single ravine, can forecast debris flow in 3 layers and meets the demand of hazard mitigation in corresponding layer.展开更多
基金Supported by the Special Project of Chinese Academy of sciences for Mountain Hazards: Debris Flow and Landslide and Oriented Project of Knowledge Innovation of Chinese Academy of sciences(KZCX2-SW-319)
文摘Through the field survey, previous researches and interpretation of aerial photos, a landslide information database of Xiaojiang Valley, Yunnan Province was set up based on the remote sensing (RS) and geographic information system (GIS) technologies. In the paper, a quantitative model for the landslide hazard assessment and zoning was presented, in which the potential energy could be obtained on basis of thorough analysis of the potential sliding volume, distance and direction of the landslide body. Taking landslide potential energy as the index of the hazard severity zonation, the study area was divided into severe, heavy, medium and light hazard zones.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20200932,BK20220582)the National Natural Science Foundation of China(32002243)+1 种基金the Postgraduate Research and Practice Innovation Program of Yangzhou University(X20211025)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Developing effective strategies to prevent diarrhea and associated-gut disorders in mammals has gained great significance.Owing to the many health benefits provided by the commensal microbiota of the intestinal tract,such as against environmental perturbation,we explored the host phenotype-associated microbes and their probiotic potential.Based on the observations that the chronic heat stress-exposed weaned piglets present as heat stress-susceptible(HS-SUS)or heat stress-resistant(HS-RES)individuals,we confirmed the phenotypic difference between the two on growth performance(P<0.05),diarrhea index(P<0.001),intestinal heat shock protein 70(HSP70)regulation(P<0.01),and inflammatory responses(P<0.01).By comparing the gut microbiome using 16S rRNA gene sequencing and KEGG functional analysis,we found that Lactobacillus johnsonii exhibited significantly higher relative abundance in the HS-RES piglets than in the HS-SUS ones(P<0.05).Further experiments using a mouse model for chemical-induced inflammation and intestinal injury demonstrated that oral administration of a representative L.johnsonii N5(isolated from the HS-RES piglets)ameliorated the clinical and histological signs of colitis while suppressing intestinal pro-inflammatory cytokines TNF-a and IL-6 production(P<0.05).We found that N5 treatment enhanced tight junction proteins ZO-1 and occludin and cytoprotective HSP70 levels under physiological condition and restored their mucosal expressions in colitis(P<0.05).In support of the high production of the anti-inflammatory cytokine IL-10,N5 promoted the intestinal Peyer’s patches MHCⅡ+and CD103+dendritic cell populations(P<0.05),increased the regulatory T(Treg)cell numbers(P<0.05),and decreased the Th17 population and its IL-17a production under physiological condition and during colitis(P<0.01).Our results shed light on understanding the interaction between commensal Lactobacillus and the host health,and provide L.johnsonii N5 as an alternative to antibiotics for preventing diarrhea and intestinal diseases.
基金This research is supported by the West Key Research Project of the National Natural Science Foundation of China(No.90202007)the Researcher Introduced Project of Chengdu Institute of Mountain Hazards and Environment,the Chinese Academy of Sciences&Ministry of Water Conservancy(Y1006).
文摘Tibet is located at the southwest boundary of China. It is the main body of the Qinghai-Tibet Plateau, the highest and the youngest plateau in the world. Owing to complicated geology, Neo-tectonic movements, geomorphology, climate and plateau environment, various mountain hazards, such as debris flow, flash flood, landslide, collapse, snow avalanche and snow drifts, are widely distributed along the Jinsha River (the upper reaches of the Yangtze River), the Nu River and the Lancang River in the east, and the Yarlungzangbo River, the Pumqu River and the Poiqu River in the south and southeast of Tibet. The distribution area of mountain hazards in Tibet is about 589,000 km2, 49.3% of its total territory. In comparison to other mountain regions in China, mountain hazards in Tibet break out unexpectedly with tremendously large scale and endanger the traffic lines, cities and towns, farmland, grassland, mountain environment, and make more dangers to the neighboring countries, such as Nepal, India, Myanmar and Bhutan. To mitigate mountain hazards, some suggestions are proposed in this paper, such as strengthening scientific research, enhancing joint studies, hazards mitigation planning, hazards warning and forecasting, controlling the most disastrous hazards and forbidding unreasonable human exploring activities in mountain areas.
文摘To reveal the gravitational erosion process in the headstream area of Jiangjia Ravine, continuous observation was conduced duing the rainy season. The observation and research show that the change of water content of the bank slope lags the precipitation process, the infiltration water concentrates mainly in the shallow layer of the bank slope, also the bank slope was unsaturated, the floods and debris flows in the gully down cut the gully bed, and scour the foot of the bank slope. These results in many collapses, which is the main type of gravitational erosion process, and it provides large amounts of loose solid materials for the eruption of debris flows.
文摘The development of urbanization has led to an increase in the number and scale of construction projects and the types of building construction engineering are getting advance and diverse due to the rapid development of technology.One of them is the static pressure prestressed pipe pile which is the most commonly used technology in modern building construction work.It is mainly used for pile foundation in construction work,and it has the advantages in less pollution,low noise,and high efficiency compared to the traditional pile foundation.Study on the characteristics of static pressure prestressed pipe pile must be carried out and strengthened the research to increase the effectiveness and quality of static pressure prestressed pipe pile on construction works.This paper is mainly to analyzed the characteristic and construction technology of static pressure prestressed pipe piles on building construction work.
基金Foundation term: Under the auspices of the Knowledge Innovation Program of Chinese Academy of Sciences(KZCX2-306)
文摘Floodwater and debris flow caused by glacial lake burst is an important land process and a serious mountain disaster in glacial area of Xizang (Tibet) Autonomous Region, and the overflow burst is mainly caused by glacial landslide falling into moraine lake. On the premise that moraine lake is full, instantaneous burst in part of the lake bank happens, as flow velocity at burst mouth caused by overflow head is higher than threshold flow velocity of glacial till. Under some supposes, d(90) and d(10) of the glacial till in the hank were used as the threshold sizes of coarse and fine grains respectively. Thus, the formula of calculating threshold flow velocity of uniform sand was simplified, and threshold flow velocity of glacial till was calculated with the formula. Then, with synthesis formula calculating flow velocity of instantaneous part burst, flow velocity at overflow burst mouth was calculated, and calculation formula of critical height (H(0)) of overflow head was derived. Overflow head was caused by volume and surge of glacial landslide falling into moraine lake, calculation formulas of ascendant height (H(1)) of lake water surface and surge height (H(2)) on burst mouth caused by glacial landslide falling into moraine lake were derived. To sum up, critical hydrologic conditions of moraine lake burst with overflow form are: the burst is inevitable as H(1) > H(0); the burst is possible as H(1) < H(0) and (H(1)+H(2)) > H(0); the burst is impossible as (H(1)+H(2)) < H(0). In the factors influencing the burst critical conditions, it is advantageous for the burst that scale of the lake is 10(5)m(2) range; terminal glacial till is more fine and is even more uniform; the width of overflow mouth is even smaller than the length of the bank; the landslide has large scale and steep slip surface; and glacial end is close to the lake. With burst of Guangxiecuo Lake in Midui Valley of the Polongzangbu River in Xizang as an example, the burst critical conditions were tested.
文摘Debris flow is one of the most destructive phenomena of natural hazards. Recently, major natural hazard, claiming human lives and assets, is due to debris flow in the world. Several practical methods for forecasting debris flow have been proposed, however, the accuracy of these methods is not high enough for practical use because of the stochastic and non-linear characteristics of debris flow. Artificial neural network has proven to be feasible and useful in developing models for nonlinear systems. On the other hand, predicting the future behavior based on a time series of collected historical data is also an important tool in many scientific applications. In this study we present a three-layer feed-forward neural network model to forecast surge of debris flow according to the time series data collected in the Jiangjia Ravine, situated in north part of Yunnan Province of China. The simulation and prediction of debris flow using the proposed approach shows this model is feasible, however, further studies are needed.
文摘Based on four kinds of methods—numerical weather prediction model, cloud image of stationary meteorological satellite, echo image of meteorological radar and telemetric rain gauge, multi space-time scale precipitation prediction products have been achieved, and multi-layer project of debris flow forecast is established with different space-time scale to get different forecast precision. The forecast system has the advantages in combination of regions and ravines, rational compounding of time and space scale. The project, which has debris flow forecast models of Sichuan province, Liangshan district and single ravine, can forecast debris flow in 3 layers and meets the demand of hazard mitigation in corresponding layer.
