Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rock...Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas.展开更多
With the continuous development of domestic highway construction,highway civil engineering and service level quality have attracted much attention.Good pavement quality and high-quality service make people feel comfor...With the continuous development of domestic highway construction,highway civil engineering and service level quality have attracted much attention.Good pavement quality and high-quality service make people feel comfortable and smooth when traveling.High-quality pavement can significantly reduce the probability of traffic accidents.At present,there is a direct relationship between pavement quality and pavement construction operations.Carrying out pavement construction operations in cold high-altitude areas requires a reasonable selection of construction equipment and methods.The application of warm-mix asphalt pavement construction technology can ensure pavement quality.Therefore,this paper analyzes the advantages of warm-mix technology,the environmental characteristics of cold high-altitude areas,and construction preparations,and discusses the construction technology of warm-mix asphalt pavement in cold high-altitude areas in detail,to improve the overall road quality of cold high-altitude areas.展开更多
China's infrastructure has gradually achieved large-scale development,and transportation construction has also shifted from east to west,transitioning from plains to mountainous areas.High-fill embankments of diff...China's infrastructure has gradually achieved large-scale development,and transportation construction has also shifted from east to west,transitioning from plains to mountainous areas.High-fill embankments of different sizes in mountainous areas are unavoidable,and the settlement of high-fill embankments is usually the most concerned issue in high-fill projects.According to the current research of highway projects,most of the high embankments in mountainous areas are soil-rock mixed embankments or rock-filled embankments,and their post-construction settlements are directly related to construction technology and the type of filler used.In this paper,the problems in the settlement control of earth-filled embankment and related factors are analyzed in detail.The settlement control technology of high-fill embankment in high-cold and high-altitude areas is also discussed,so as to ensure the overall quality of high-fill embankment.展开更多
In collaboration with 12 other institutions, the Meteorological Observation Center of the China Meteorological Administration undertook a comprehensive marine observation experiment in the South China Sea using the Yi...In collaboration with 12 other institutions, the Meteorological Observation Center of the China Meteorological Administration undertook a comprehensive marine observation experiment in the South China Sea using the Yilong-10 high-altitude large unmanned aerial vehicle(UAV). The Yilong-10 UAV carried a self-developed dropsonde system and a millimeter-wave cloud radar system. In addition, a solar-powered unmanned surface vessel and two drifting buoys were used. The experiment was further supported by an intelligent, reciprocating horizontal drifting radiosonde system that was deployed from the Sansha Meteorological Observing Station, with the intent of producing a stereoscopic observation over the South China Sea. Comprehensive three-dimensional observations were collected using the system from 31 July to2 August, 2020. This information was used to investigate the formation and development processes of Typhoon Sinlaku(2020). The data contain measurements of 21 oceanic and meteorological parameters acquired by the five devices, along with video footage from the UAV. The data proved very helpful in determining the actual location and intensity of Typhoon Sinlaku(2020). The experiment demonstrates the feasibility of using a high-altitude, large UAV to fill in the gaps between operational meteorological observations of marine areas and typhoons near China, and marks a milestone for the use of such data for analyzing the structure and impact of a typhoon in the South China Sea. It also demonstrates the potential for establishing operational UAV meteorological observing systems in the future, and the assimilation of such data into numerical weather prediction models.展开更多
Due to the severe restrictions of natural conditions and ecological environment,high-altitude mountainous areas usually become the " hard bones" in the battle against poverty. Xueshan Township,Luquan Yi and ...Due to the severe restrictions of natural conditions and ecological environment,high-altitude mountainous areas usually become the " hard bones" in the battle against poverty. Xueshan Township,Luquan Yi and Miao Autonomous County of Yunnan Province,located in the alpine valley of Jinsha River,is a major township with wide and deep poverty,and the incidence of poverty is up to 45. 00%. In recent years,Xueshan Township has insisted on the battle against poverty,made effort to develop the Codonopsis pilosula industry,and successfully developed a road to poverty alleviation through C. pilosula industry,and formed a unique industrial poverty alleviation model by the end of 2018,the incidence of poverty dropped to 0. 74%. Based on field survey and interview,this paper analyzes and summarizes the specific practices,main results,practical experience and promotion and application measures of the poverty alleviation model of C. pilosula planting industry in Xueshan Township,in the hope of providing certain reference for the targeted poverty alleviation in similar areas in Yunnan Province and other provinces of China.展开更多
Ice nucleating particle(INP) measurements were made at two high-altitude stations in India. Aerosols collected on filter paper at Girawali Observatory, Inter University Center for Astronomy & Astrophysics(IGO), an...Ice nucleating particle(INP) measurements were made at two high-altitude stations in India. Aerosols collected on filter paper at Girawali Observatory, Inter University Center for Astronomy & Astrophysics(IGO), and at the Radio Astronomy Center, Ooty(RAC), were activated in deposition mode using a thermal gradient diffusion chamber to determine the INP concentrations. The measurement campaigns at IGO were conducted during 2011, 2013 and 2014, and at RAC during 2013 and 2014. When the aerosol samples were exposed to an ice supersaturation of between 5% and 23% in the temperature range^(-1)7.6?C to-22?C, the maximum INP number concentration at IGO and RAC was 1.0 L^(-1) and 1.6 L^(-1), respectively.A maximum correlation coefficient of 0.76 was observed between the INP number concentration and ice supersaturation. The airmass trajectories analyzed for the measurement campaigns showed that the Arabian Desert and arid regions were the main INP contributors. Elemental analysis of particles showed the presence of Na, Cl, Si, Al, Fe, Cu, Co, Cd, S, Mn and K, as well as some rare-Earth elements like Mo, Ru, La, Ce, V and Zr. When aerosols in the size range 0.5–20 μm were considered, the fraction that acted as INPs was 1 : 10~4 to 1 : 10~6 at IGO, and 1 : 10~3 to 1 : 10~4 at RAC. The higher ratio of INPs to aerosols at RAC than IGO may be attributable to the presence of rare-Earth elements observed in the aerosol samples at RAC, which were absent at IGO.展开更多
BACKGROUND Colon cancer is associated with a higher incidence among residents in highaltitude areas.Hypoxic environment at high altitudes inhibits the phagocytic and oxygen-dependent killing function of phagocytes,the...BACKGROUND Colon cancer is associated with a higher incidence among residents in highaltitude areas.Hypoxic environment at high altitudes inhibits the phagocytic and oxygen-dependent killing function of phagocytes,thereby increasing the inflammatory factors,inhibiting the body’s innate immunity and increasing the risk of colon cancer.AIM To examine the effect of minimally invasive surgery vs laparotomy in patients with colon cancer residing in high-altitude areas.METHODS Ninety-two patients with colon cancer in our hospital from January 2019 to February 2021 were selected and divided into the minimally invasive surgery and laparotomy groups using the random number table method,with 46 patients in each group.Minimally invasive surgery was performed in the minimally invasive group and laparotomy in the laparotomy group.Operative conditions,inflammatory index pre-and post-surgery,immune function index and complication probability were measured.RESULTS Operative duration was significantly longer and intraoperative blood loss and recovery time of gastrointestinal function were significantly less(all P<0.05)in the minimally invasive group than in the laparotomy group.The number of lymph nodes dissected was not significantly different.Before surgery,there were no significant differences in serum C-reactive protein,interleukin-6 and tumor necrosis factor-αlevels between the groups,whereas after surgery,the levels were significantly higher in the minimally invasive group(26.98±6.91 mg/L,146.38±11.23 ng/mL and 83.51±8.69 pg/mL vs 41.15±8.39 mg/L,186.79±15.36 ng/mL and 110.65±12.84 pg/mL,respectively,P<0.05).Furthermore,before surgery,there were no significant differences in CD3+,CD4+and CD4+/CD8+levels between the groups,whereas after surgery,the levels decreased in both groups,being significantly higher in the minimally invasive group(55.61%±4.39%,35.45%±3.67%and 1.30±0.35 vs 49.68%±5.33%,31.21%±3.25%and 1.13±0.30,respectively,P<0.05).Complication probability was significantly lower in the minimally invasive group(4.35%vs 17.39%,P<0.05).CONCLUSION Laparoscopic minimally invasive procedures reduce surgical trauma and alleviate the inflammatory response and immune dysfunction caused by invasive operation.It also shortens recovery time and reduces complication probability.展开更多
The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly...The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.展开更多
Diet and feeding behavior data are crucial to a deep understanding of the behavioral response and adaptation of primates to a high-altitude environment.From August 2019 to June 2021,we collected data on the feeding be...Diet and feeding behavior data are crucial to a deep understanding of the behavioral response and adaptation of primates to a high-altitude environment.From August 2019 to June 2021,we collected data on the feeding behavior of a high-altitude rhesus macaque Macaca mulatta group from Yajiang County,Western Sichuan Plateau,which has an altitude of over 3,500 m.The results showed that feeding(33.0±1.8%)and moving(28.3±2.6%)were the dominant behavior of rhesus macaques.Macaques ate 193 food items,comprising 11 food categories from 90 species.Our study found that plant roots(30.9±30.1%)and young leaves(28.0±33.1%)were the main foods eaten by macaques.The preferred foods of rhesus macaques were young leaves,fruits,and seeds,and the consumption of these items was positively correlated with its food availability.When the availability of preferred foods was low,macaques took plant roots,barks,and fallen leaves as fallback foods.In particular,roots were a dominant food item in winter,and this way of feeding became a key survival strategy.Our results suggest that,facing the relative scarcity and strong seasonal fluctuations of food resources in high-altitude habitat,macaques adopt active foraging strategies,relying on a variety of food species and adjusting flexibly their food choices based on food availability,which may help to maximize the energy efficiency of high-altitude macaques.展开更多
DNA methylation(DNAm)is one of the major epigenetic mechanisms in humans and is important in diverse cellular processes.The variation of DNAm in the human population is related to both genetic and environmental factor...DNA methylation(DNAm)is one of the major epigenetic mechanisms in humans and is important in diverse cellular processes.The variation of DNAm in the human population is related to both genetic and environmental factors.However,the DNAm profiles have not been investigated in the Chinese population of diverse ethnicities.Here,we performed double-strand bisulfite sequencing(DSBS)for 32 Chinese individuals representing four major ethnic groups including Han Chinese,Tibetan,Zhuang,and Mongolian.We identified a total of 604,649 SNPs and quantified DNAm at more than 14 million Cp Gs in the population.We found global DNAm-based epigenetic structure is different from the genetic structure of the population,and ethnic difference only partially explains the variation of DNAm.Surprisingly,non-ethnic-specific DNAm variations showed stronger correlation with the global genetic divergence than these ethnic-specific DNAm.Differentially methylated regions(DMRs)among these ethnic groups were found around genes in diverse biological processes.Especially,these DMR-genes between Tibetan and nonTibetans were enriched around high-altitude genes including EPAS1 and EGLN1,suggesting DNAm alteration plays an important role in high-altitude adaptation.Our results provide the first batch of epigenetic maps for Chinese populations and the first evidence of the association of epigenetic changes with Tibetans'high-altitude adaptation.展开更多
The surrounding rock needs shotcrete support after drilling and blasting excavation in the tunnel;the high concentration of dust generated in the process will endanger workers'occupational health.Therefore,to ensu...The surrounding rock needs shotcrete support after drilling and blasting excavation in the tunnel;the high concentration of dust generated in the process will endanger workers'occupational health.Therefore,to ensure the cleanness and safety of the tunnel construction process,a full-scale model of the tunnel was established based on field data of a high-altitude tunnel of the Sichuan-Tibet railway.The dust production mechanism is summarized by combing the whole process of shotcrete.The Computa-tional Fluid Dynamics(CFD)method was used to study the diffusion and transport of dust under different conditions.The grey relational analysis was applied to investigate the correlation values of the influ-encing factors on dust diffusion in the shotcrete operation area.The results show that the dust gener-ation mechanism of shotcrete includes the sudden change of particle velocity in the jet area leading to escape and particle impact dust generation,where fine dust is easily dispersed in the tunnel.During continuous dust production,the dust concentration is higher near the wet spraying machine and on the backflow side of the working face.Increasing the air supply volume and shortening the distance between the air duct and the working face is conducive to diluting the dust concentration in the tunnel.In the high-altitude environment,the dust concentration in the tunnel decreases,the diffusion distance be-comes smaller,the settlement proportion of dust particles increases,and the risk of secondary pollution increases.The simulation results and the field measurement data are consistent,which can provide theoretical support for the construction site dust control.展开更多
The Tibetan Partridge(Perdix hodgsoniae)is an endemic species distributed in high-altitude areas of 3600–5600 m on the Qinghai–Tibet Plateau.To explore how the species is adapted to the high elevation environment,we...The Tibetan Partridge(Perdix hodgsoniae)is an endemic species distributed in high-altitude areas of 3600–5600 m on the Qinghai–Tibet Plateau.To explore how the species is adapted to the high elevation environment,we as-sembled a draft genome based on both the Illumina and PacBio sequencing platforms with its population genetics and genomics analysis.In total,134.74 Gb short reads and 30.81 Gb long reads raw data were generated.The 1.05-Gb assembled genome had a contig N50 of 4.56 Mb,with 91.94%complete BUSCOs.The 17457 genes were annotated,and 11.35%of the genome was composed of repeat sequences.The phylogenetic tree showed that P.hodgsoniae was located at the basal position of the clade,including Golden Pheasant(Chrysolophus pictus),Common Pheasant(Phasianus colchicus),and Mikado Pheasant(Syrmaticus mikado).We found that 1014,2595,and 2732 of the 6641 one-to-one orthologous genes were under positive selection in P.hodgsoniae,detected using PAML,BUSTED,and aBSREL programs,respectively,of which 965 genes were common under positive selec-tion with 3 different programs.Several positively selected genes and immunity pathways relevant to high-altitude adaptation were detected.Gene family evolution showed that 99 gene families experienced significant expansion events,while 6 gene families were under contraction.The total number of olfactory receptor genes was relatively low in P.hodgsoniae.Genomic data provide an important resource for a further study on the evolutionary history of P.hodgsoniae,which provides a new insight into its high-altitude adaptation mechanisms.展开更多
High altitude brings a great physiological change in human beings,both during short-term exposure and in lifelong residents,especially in the cardiovascular system.Hypoxia notably induces pulmonary vasoconstriction,th...High altitude brings a great physiological change in human beings,both during short-term exposure and in lifelong residents,especially in the cardiovascular system.Hypoxia notably induces pulmonary vasoconstriction,thus resulting in a moderate increase in pulmonary arterial pressure.Acclimatized inhabitants exhibit lower pulmonary pressure and better exercise capacity than lowlanders during short-term high-altitude exposure.Rapid ascent to high altitude without adequate acclimatization can cause high-altitude pulmonary edema in susceptible individuals,with a rapid increase in pulmonary pressure.Cardiac output increases initially following acute high-altitude exposure and returns to normal as at sea level after a few days of acclimatization.Ventricular volumes at high altitude change consistently with decreases in plasma volume.Left ventricular systolic function is enhanced after acute high-altitude exposure and during chronic acclimatization.However,there are controversies on whether right ventricular systolic function is preserved or decreases after high-altitude exposure,probably due to variable hypoxic pulmonary vasoconstriction.High altitude induces altered ventricular diastolic patterns.Recently,a new perspective has emerged,whereby ventricular intrinsic relaxation is not impaired,as assessed by untwisting through speckle-tracking imaging.Persistent hypoxic pulmonary hypertension probably induced right ventricular dilation and hypertrophy,and even right heart failure,described as high-altitude heart diseases.Descent to lower altitude should be the best treatment for them,and potential pharmacological agents majorly focus on the inhabitation of pulmonary vasoconstriction,such as phosphodiesterase-5 inhibitors and endothelin receptor antagonists.Evidence on the risks of high-altitude exposure for patients with previous cardiovascular diseases is limited,and thus they should be prudent when ascending to high altitude.Further randomized large-scale studies are needed to explore cardiac performance at high altitudes and provide more evidence for the prevention and clinical management of medical complications at high altitude.展开更多
As an invisible“endocrine organ”,gut microbiota is widely involved in the regulation of nervous system,endocrine system,circulatory system,and digestive system.It is also closely related to host health and the occur...As an invisible“endocrine organ”,gut microbiota is widely involved in the regulation of nervous system,endocrine system,circulatory system,and digestive system.It is also closely related to host health and the occurrence of many chronic diseases.Relevant literature shows that high temperature,low temperature,and highaltitude hypoxia may have negative effects on commensal microorganisms.The stimulation of exercise may aggravate this reaction,which is related to the occurrence of exercise-induced fever and gastrointestinal and respiratory diseases.The intervention of probiotics can alleviate the above problems to a certain extent.Therefore,this paper takes exercise in a special environment as the starting point,deeply analyses the intervention effect and potential mechanism of probiotics,and provides the theoretical basis and reference for follow-up research and application of probiotics in sports science.展开更多
Two models are used to simulate the high-altitude permafrost distribution on the Qinghai-Xizang Plateau. The two models are the 'altitude model', a Gaussian distribution function used to describe the latitudin...Two models are used to simulate the high-altitude permafrost distribution on the Qinghai-Xizang Plateau. The two models are the 'altitude model', a Gaussian distribution function used to describe the latitudinal zonation of permafrost based on the three-dimensional rules of high-altitude permafrost, and the 'frost number model', a dimensionless ratio defined by manipulation of freezing and thawing degree-day sums. The results show that the 'altitude model' can simulate the high-altitude permafrost distribution under present climate conditions accurately. Given the essential hypotheses and using the GCM scenarios from HADCM2, the 'altitude model' is used for predicting the permafrost distribution change on the Qinghai-Xizang Plateau. The results show that the permafrost on the plateau will not change significantly during 20—50 a, the percentage of the total disappeared area will not be over 19%. However, by the year 2099, if the air temperature increases by an average of 2.91℃ on the plateau, the展开更多
Arabidopsis thaliana(A.thaliana)has long been a model species for dicotyledon study,and was the first flowering plant to get its genome completed sequenced[1].Although most wild A.thaliana are collected in Europe,seve...Arabidopsis thaliana(A.thaliana)has long been a model species for dicotyledon study,and was the first flowering plant to get its genome completed sequenced[1].Although most wild A.thaliana are collected in Europe,several studies have found a rapid A.thaliana west-east expansion from Central Asia[2].The Qinghai-Tibet Plateau(QTP)is close to Central Asia and known for its high alti-展开更多
High-altitude cerebral edema(HACE)is a potentially fatal encephalopathy associated with a time-dependent exposure to the hypobaric hypoxia of altitude.The formation of HACE is affected by both vasogenic and cytotoxic ...High-altitude cerebral edema(HACE)is a potentially fatal encephalopathy associated with a time-dependent exposure to the hypobaric hypoxia of altitude.The formation of HACE is affected by both vasogenic and cytotoxic edema.The over-activated microglia potentiate the damage of blood-brain barrier(BBB)and exacerbate cytotoxic edema.In light with the activation of microglia in HACE,we aimed to investigate whether the over-activated microglia were the key turning point of acute mountain sickness to HACE.In in vivo experiments,by exposing mice to hypobaric hypoxia(7000 m above sea level)to induce HACE model,we found that microglia were activated and migrated to blood vessels.Microglia depletion by PLX5622 obviously relieved brain edema.In in vitro experiments,we found that hypoxia induced cultured microglial activation,leading to the destruction of endothelial tight junction and astrocyte swelling.Up-regulated nuclear respiratory factor 1(NRF1)accelerated pro-inflammatory factors through transcriptional regulation on nuclearfactorkappa B p65(NF-kB p65)and mitochondrial transcription factorA(TFAM)in activated microglia under hypoxia.NRF1 also up-regulated phagocytosis by transcriptional regulation on caveolin-1(CAV-1)and adaptorrelated protein complex 2 subunit beta(AP2B1).The present study reveals a new mechanism in HACE:hypoxia over-activates microglia through up-regulation of NRF1,which both induces inflammatory response through transcriptionally activating NF-kB p65 and TFAM,and enhances phagocytic function through up-regulation of CAV-1 and AP2B1;hypoxia-activatedmicroglia destroy the integrity of BBB and release pro-inflammatory factors that eventually induce HACE.展开更多
This letter presents a systematic approach to estimate the annual energy production(AEP) of variable-speed wind turbines erected at high-altitude sites. Compared with the existing empirical-model based approaches, the...This letter presents a systematic approach to estimate the annual energy production(AEP) of variable-speed wind turbines erected at high-altitude sites. Compared with the existing empirical-model based approaches, the proposed approach models the influence of the air density on the power production while employing the theoretical power curve. Consequently, the proposed approach provides a precise estimation of AEP, which can serve as a foundation of the optimum turbinesite matching design at different-altitude sites.展开更多
Can a planned merger bring two loss-making Shanghai air carriers back to life?By pursuing a merger with Shanghai Airlines Corp. Ltd., the struggling air travel giant China Eastern Airlines Corp. Ltd. is injecting some...Can a planned merger bring two loss-making Shanghai air carriers back to life?By pursuing a merger with Shanghai Airlines Corp. Ltd., the struggling air travel giant China Eastern Airlines Corp. Ltd. is injecting some steam into what looks to be a languid season.展开更多
In this study,we investigated the motion,shape,and delayed radiation intensity of a radioactive cloud by establishing a volume-source model of delayed radiation after high-altitude nuclear explosions.Then,the spatial ...In this study,we investigated the motion,shape,and delayed radiation intensity of a radioactive cloud by establishing a volume-source model of delayed radiation after high-altitude nuclear explosions.Then,the spatial distribution of electron number density at different moments on the north side of the explosion point generated by delayed γ-rays and delayed β-rays from the radioactive cloud under the influence of the geomagnetic field was calculated by solving chemical reaction kinetics equations.The impact of radio communication in the different frequency bands on the process of atmospheric ionization was also studied.The numerical results of the high-altitude nuclear explosion (120 km high and with a 1 megaton equivalent at 40°N latitude) indicated that the peak of electron number density ionized delayed γ-rays is located at a height of approximately 100 km and that of electron number density ionized delayed β-rays is about 90 km high.After 1 min of explosion,the radio communication in the medium frequency (MF) and high-frequency (HF)bands was completely interrupted,and the energy attenuation of the radio wave in the very high-frequency (VHF)band was extremely high.Five minutes later,the VHF radio communication was basically restored,but the energy attenuation in the HF band was still high.After 30 min,theVHF radio communication returned to normal,but its influence on the HF and MF radio communication continued.展开更多
基金This work was financially supported by National Natural Science Foundation of China(Grant Nos.U2244226,U2244227 and 42177172).
文摘Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas.
文摘With the continuous development of domestic highway construction,highway civil engineering and service level quality have attracted much attention.Good pavement quality and high-quality service make people feel comfortable and smooth when traveling.High-quality pavement can significantly reduce the probability of traffic accidents.At present,there is a direct relationship between pavement quality and pavement construction operations.Carrying out pavement construction operations in cold high-altitude areas requires a reasonable selection of construction equipment and methods.The application of warm-mix asphalt pavement construction technology can ensure pavement quality.Therefore,this paper analyzes the advantages of warm-mix technology,the environmental characteristics of cold high-altitude areas,and construction preparations,and discusses the construction technology of warm-mix asphalt pavement in cold high-altitude areas in detail,to improve the overall road quality of cold high-altitude areas.
文摘China's infrastructure has gradually achieved large-scale development,and transportation construction has also shifted from east to west,transitioning from plains to mountainous areas.High-fill embankments of different sizes in mountainous areas are unavoidable,and the settlement of high-fill embankments is usually the most concerned issue in high-fill projects.According to the current research of highway projects,most of the high embankments in mountainous areas are soil-rock mixed embankments or rock-filled embankments,and their post-construction settlements are directly related to construction technology and the type of filler used.In this paper,the problems in the settlement control of earth-filled embankment and related factors are analyzed in detail.The settlement control technology of high-fill embankment in high-cold and high-altitude areas is also discussed,so as to ensure the overall quality of high-fill embankment.
基金supported by the Petrel Meteorological Observation Experiment Project of the China Meteorological Administration and the “Adaptive Improvement of New Observation Platform for Typhoon Observation (2018YFC1506401)” of the Ministry of Science and Technology。
文摘In collaboration with 12 other institutions, the Meteorological Observation Center of the China Meteorological Administration undertook a comprehensive marine observation experiment in the South China Sea using the Yilong-10 high-altitude large unmanned aerial vehicle(UAV). The Yilong-10 UAV carried a self-developed dropsonde system and a millimeter-wave cloud radar system. In addition, a solar-powered unmanned surface vessel and two drifting buoys were used. The experiment was further supported by an intelligent, reciprocating horizontal drifting radiosonde system that was deployed from the Sansha Meteorological Observing Station, with the intent of producing a stereoscopic observation over the South China Sea. Comprehensive three-dimensional observations were collected using the system from 31 July to2 August, 2020. This information was used to investigate the formation and development processes of Typhoon Sinlaku(2020). The data contain measurements of 21 oceanic and meteorological parameters acquired by the five devices, along with video footage from the UAV. The data proved very helpful in determining the actual location and intensity of Typhoon Sinlaku(2020). The experiment demonstrates the feasibility of using a high-altitude, large UAV to fill in the gaps between operational meteorological observations of marine areas and typhoons near China, and marks a milestone for the use of such data for analyzing the structure and impact of a typhoon in the South China Sea. It also demonstrates the potential for establishing operational UAV meteorological observing systems in the future, and the assimilation of such data into numerical weather prediction models.
基金Commissioned Project of Office of Rural Work Leading Group of Kunming Municipal Committee of the Communist Party of China "Study on the Poverty Alleviation Model of Kunming City in the Context of World Poverty Reduction"Construction Project of Party Branch Secretary’s Studio of "Double Leader" Teachers in Colleges and Universities of the Ministry of Education of China
文摘Due to the severe restrictions of natural conditions and ecological environment,high-altitude mountainous areas usually become the " hard bones" in the battle against poverty. Xueshan Township,Luquan Yi and Miao Autonomous County of Yunnan Province,located in the alpine valley of Jinsha River,is a major township with wide and deep poverty,and the incidence of poverty is up to 45. 00%. In recent years,Xueshan Township has insisted on the battle against poverty,made effort to develop the Codonopsis pilosula industry,and successfully developed a road to poverty alleviation through C. pilosula industry,and formed a unique industrial poverty alleviation model by the end of 2018,the incidence of poverty dropped to 0. 74%. Based on field survey and interview,this paper analyzes and summarizes the specific practices,main results,practical experience and promotion and application measures of the poverty alleviation model of C. pilosula planting industry in Xueshan Township,in the hope of providing certain reference for the targeted poverty alleviation in similar areas in Yunnan Province and other provinces of China.
文摘Ice nucleating particle(INP) measurements were made at two high-altitude stations in India. Aerosols collected on filter paper at Girawali Observatory, Inter University Center for Astronomy & Astrophysics(IGO), and at the Radio Astronomy Center, Ooty(RAC), were activated in deposition mode using a thermal gradient diffusion chamber to determine the INP concentrations. The measurement campaigns at IGO were conducted during 2011, 2013 and 2014, and at RAC during 2013 and 2014. When the aerosol samples were exposed to an ice supersaturation of between 5% and 23% in the temperature range^(-1)7.6?C to-22?C, the maximum INP number concentration at IGO and RAC was 1.0 L^(-1) and 1.6 L^(-1), respectively.A maximum correlation coefficient of 0.76 was observed between the INP number concentration and ice supersaturation. The airmass trajectories analyzed for the measurement campaigns showed that the Arabian Desert and arid regions were the main INP contributors. Elemental analysis of particles showed the presence of Na, Cl, Si, Al, Fe, Cu, Co, Cd, S, Mn and K, as well as some rare-Earth elements like Mo, Ru, La, Ce, V and Zr. When aerosols in the size range 0.5–20 μm were considered, the fraction that acted as INPs was 1 : 10~4 to 1 : 10~6 at IGO, and 1 : 10~3 to 1 : 10~4 at RAC. The higher ratio of INPs to aerosols at RAC than IGO may be attributable to the presence of rare-Earth elements observed in the aerosol samples at RAC, which were absent at IGO.
基金the People’s Hospital of Tibet Autonomous Region Institutional Review Board(Approval No.METBHP-21-KJ-025).
文摘BACKGROUND Colon cancer is associated with a higher incidence among residents in highaltitude areas.Hypoxic environment at high altitudes inhibits the phagocytic and oxygen-dependent killing function of phagocytes,thereby increasing the inflammatory factors,inhibiting the body’s innate immunity and increasing the risk of colon cancer.AIM To examine the effect of minimally invasive surgery vs laparotomy in patients with colon cancer residing in high-altitude areas.METHODS Ninety-two patients with colon cancer in our hospital from January 2019 to February 2021 were selected and divided into the minimally invasive surgery and laparotomy groups using the random number table method,with 46 patients in each group.Minimally invasive surgery was performed in the minimally invasive group and laparotomy in the laparotomy group.Operative conditions,inflammatory index pre-and post-surgery,immune function index and complication probability were measured.RESULTS Operative duration was significantly longer and intraoperative blood loss and recovery time of gastrointestinal function were significantly less(all P<0.05)in the minimally invasive group than in the laparotomy group.The number of lymph nodes dissected was not significantly different.Before surgery,there were no significant differences in serum C-reactive protein,interleukin-6 and tumor necrosis factor-αlevels between the groups,whereas after surgery,the levels were significantly higher in the minimally invasive group(26.98±6.91 mg/L,146.38±11.23 ng/mL and 83.51±8.69 pg/mL vs 41.15±8.39 mg/L,186.79±15.36 ng/mL and 110.65±12.84 pg/mL,respectively,P<0.05).Furthermore,before surgery,there were no significant differences in CD3+,CD4+and CD4+/CD8+levels between the groups,whereas after surgery,the levels decreased in both groups,being significantly higher in the minimally invasive group(55.61%±4.39%,35.45%±3.67%and 1.30±0.35 vs 49.68%±5.33%,31.21%±3.25%and 1.13±0.30,respectively,P<0.05).Complication probability was significantly lower in the minimally invasive group(4.35%vs 17.39%,P<0.05).CONCLUSION Laparoscopic minimally invasive procedures reduce surgical trauma and alleviate the inflammatory response and immune dysfunction caused by invasive operation.It also shortens recovery time and reduces complication probability.
基金supported by the National Natural Science Foundation of China(Grant Nos.41888101,41977380 and 42072033)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB26000000 and XDA2004010102)+3 种基金the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0601)the National Social Science Foundation of China(Grant No.21@WTK001)supported by the Chinese Academy of Sciences President’s International Fellowship Initiative Award(Grant No.2018VCA0016)the Je Tsongkhapa Endowment for Central and Inner Asian Archaeology at the University of Arizona。
文摘The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.
基金This study was supported by the National Natural Science Foundation of China(31870355,31960106).
文摘Diet and feeding behavior data are crucial to a deep understanding of the behavioral response and adaptation of primates to a high-altitude environment.From August 2019 to June 2021,we collected data on the feeding behavior of a high-altitude rhesus macaque Macaca mulatta group from Yajiang County,Western Sichuan Plateau,which has an altitude of over 3,500 m.The results showed that feeding(33.0±1.8%)and moving(28.3±2.6%)were the dominant behavior of rhesus macaques.Macaques ate 193 food items,comprising 11 food categories from 90 species.Our study found that plant roots(30.9±30.1%)and young leaves(28.0±33.1%)were the main foods eaten by macaques.The preferred foods of rhesus macaques were young leaves,fruits,and seeds,and the consumption of these items was positively correlated with its food availability.When the availability of preferred foods was low,macaques took plant roots,barks,and fallen leaves as fallback foods.In particular,roots were a dominant food item in winter,and this way of feeding became a key survival strategy.Our results suggest that,facing the relative scarcity and strong seasonal fluctuations of food resources in high-altitude habitat,macaques adopt active foraging strategies,relying on a variety of food species and adjusting flexibly their food choices based on food availability,which may help to maximize the energy efficiency of high-altitude macaques.
基金the National Key Research and Development Program of China(2016YFC0900402)the Basic Science Center Program(32288101)+1 种基金the National Natural Science Foundation of China(32030020 and 31961130380)the Shanghai Municipal Science and Technology Major Project(2017SHZDZX01)。
文摘DNA methylation(DNAm)is one of the major epigenetic mechanisms in humans and is important in diverse cellular processes.The variation of DNAm in the human population is related to both genetic and environmental factors.However,the DNAm profiles have not been investigated in the Chinese population of diverse ethnicities.Here,we performed double-strand bisulfite sequencing(DSBS)for 32 Chinese individuals representing four major ethnic groups including Han Chinese,Tibetan,Zhuang,and Mongolian.We identified a total of 604,649 SNPs and quantified DNAm at more than 14 million Cp Gs in the population.We found global DNAm-based epigenetic structure is different from the genetic structure of the population,and ethnic difference only partially explains the variation of DNAm.Surprisingly,non-ethnic-specific DNAm variations showed stronger correlation with the global genetic divergence than these ethnic-specific DNAm.Differentially methylated regions(DMRs)among these ethnic groups were found around genes in diverse biological processes.Especially,these DMR-genes between Tibetan and nonTibetans were enriched around high-altitude genes including EPAS1 and EGLN1,suggesting DNAm alteration plays an important role in high-altitude adaptation.Our results provide the first batch of epigenetic maps for Chinese populations and the first evidence of the association of epigenetic changes with Tibetans'high-altitude adaptation.
基金the National Natural Science Foundation of China(grant No.51874016).
文摘The surrounding rock needs shotcrete support after drilling and blasting excavation in the tunnel;the high concentration of dust generated in the process will endanger workers'occupational health.Therefore,to ensure the cleanness and safety of the tunnel construction process,a full-scale model of the tunnel was established based on field data of a high-altitude tunnel of the Sichuan-Tibet railway.The dust production mechanism is summarized by combing the whole process of shotcrete.The Computa-tional Fluid Dynamics(CFD)method was used to study the diffusion and transport of dust under different conditions.The grey relational analysis was applied to investigate the correlation values of the influ-encing factors on dust diffusion in the shotcrete operation area.The results show that the dust gener-ation mechanism of shotcrete includes the sudden change of particle velocity in the jet area leading to escape and particle impact dust generation,where fine dust is easily dispersed in the tunnel.During continuous dust production,the dust concentration is higher near the wet spraying machine and on the backflow side of the working face.Increasing the air supply volume and shortening the distance between the air duct and the working face is conducive to diluting the dust concentration in the tunnel.In the high-altitude environment,the dust concentration in the tunnel decreases,the diffusion distance be-comes smaller,the settlement proportion of dust particles increases,and the risk of secondary pollution increases.The simulation results and the field measurement data are consistent,which can provide theoretical support for the construction site dust control.
基金The National Center for Biotechnology Information(NCBI)BioProject and BioSample accession numbers of Perdix hodgsoniae are PRJNA760267 and SAMN21212221,respectivelyThe raw reads have been deposited in the NCBI SRA database with the accession numbers SRR15900414(Illumina),SRR15900412,and SRR15900413(PacBio).
文摘The Tibetan Partridge(Perdix hodgsoniae)is an endemic species distributed in high-altitude areas of 3600–5600 m on the Qinghai–Tibet Plateau.To explore how the species is adapted to the high elevation environment,we as-sembled a draft genome based on both the Illumina and PacBio sequencing platforms with its population genetics and genomics analysis.In total,134.74 Gb short reads and 30.81 Gb long reads raw data were generated.The 1.05-Gb assembled genome had a contig N50 of 4.56 Mb,with 91.94%complete BUSCOs.The 17457 genes were annotated,and 11.35%of the genome was composed of repeat sequences.The phylogenetic tree showed that P.hodgsoniae was located at the basal position of the clade,including Golden Pheasant(Chrysolophus pictus),Common Pheasant(Phasianus colchicus),and Mikado Pheasant(Syrmaticus mikado).We found that 1014,2595,and 2732 of the 6641 one-to-one orthologous genes were under positive selection in P.hodgsoniae,detected using PAML,BUSTED,and aBSREL programs,respectively,of which 965 genes were common under positive selec-tion with 3 different programs.Several positively selected genes and immunity pathways relevant to high-altitude adaptation were detected.Gene family evolution showed that 99 gene families experienced significant expansion events,while 6 gene families were under contraction.The total number of olfactory receptor genes was relatively low in P.hodgsoniae.Genomic data provide an important resource for a further study on the evolutionary history of P.hodgsoniae,which provides a new insight into its high-altitude adaptation mechanisms.
基金the National Natural Science Foundation of China(81730054)Military Logistics Research Project,PLA(BLJ18J007)。
文摘High altitude brings a great physiological change in human beings,both during short-term exposure and in lifelong residents,especially in the cardiovascular system.Hypoxia notably induces pulmonary vasoconstriction,thus resulting in a moderate increase in pulmonary arterial pressure.Acclimatized inhabitants exhibit lower pulmonary pressure and better exercise capacity than lowlanders during short-term high-altitude exposure.Rapid ascent to high altitude without adequate acclimatization can cause high-altitude pulmonary edema in susceptible individuals,with a rapid increase in pulmonary pressure.Cardiac output increases initially following acute high-altitude exposure and returns to normal as at sea level after a few days of acclimatization.Ventricular volumes at high altitude change consistently with decreases in plasma volume.Left ventricular systolic function is enhanced after acute high-altitude exposure and during chronic acclimatization.However,there are controversies on whether right ventricular systolic function is preserved or decreases after high-altitude exposure,probably due to variable hypoxic pulmonary vasoconstriction.High altitude induces altered ventricular diastolic patterns.Recently,a new perspective has emerged,whereby ventricular intrinsic relaxation is not impaired,as assessed by untwisting through speckle-tracking imaging.Persistent hypoxic pulmonary hypertension probably induced right ventricular dilation and hypertrophy,and even right heart failure,described as high-altitude heart diseases.Descent to lower altitude should be the best treatment for them,and potential pharmacological agents majorly focus on the inhabitation of pulmonary vasoconstriction,such as phosphodiesterase-5 inhibitors and endothelin receptor antagonists.Evidence on the risks of high-altitude exposure for patients with previous cardiovascular diseases is limited,and thus they should be prudent when ascending to high altitude.Further randomized large-scale studies are needed to explore cardiac performance at high altitudes and provide more evidence for the prevention and clinical management of medical complications at high altitude.
基金National Natural Science Foundation of China(11775059)National Key Technology R&D Program of China(2019YFF0301600).
文摘As an invisible“endocrine organ”,gut microbiota is widely involved in the regulation of nervous system,endocrine system,circulatory system,and digestive system.It is also closely related to host health and the occurrence of many chronic diseases.Relevant literature shows that high temperature,low temperature,and highaltitude hypoxia may have negative effects on commensal microorganisms.The stimulation of exercise may aggravate this reaction,which is related to the occurrence of exercise-induced fever and gastrointestinal and respiratory diseases.The intervention of probiotics can alleviate the above problems to a certain extent.Therefore,this paper takes exercise in a special environment as the starting point,deeply analyses the intervention effect and potential mechanism of probiotics,and provides the theoretical basis and reference for follow-up research and application of probiotics in sports science.
基金Project "Fundamental Research of Cryosphere" supported by the Chinese Academy of Sciences.
文摘Two models are used to simulate the high-altitude permafrost distribution on the Qinghai-Xizang Plateau. The two models are the 'altitude model', a Gaussian distribution function used to describe the latitudinal zonation of permafrost based on the three-dimensional rules of high-altitude permafrost, and the 'frost number model', a dimensionless ratio defined by manipulation of freezing and thawing degree-day sums. The results show that the 'altitude model' can simulate the high-altitude permafrost distribution under present climate conditions accurately. Given the essential hypotheses and using the GCM scenarios from HADCM2, the 'altitude model' is used for predicting the permafrost distribution change on the Qinghai-Xizang Plateau. The results show that the permafrost on the plateau will not change significantly during 20—50 a, the percentage of the total disappeared area will not be over 19%. However, by the year 2099, if the air temperature increases by an average of 2.91℃ on the plateau, the
基金supported by the National Natural Science Foundation of China (91131901)the specimen platform of China (teaching specimens sub-platform) and PSCIRT project
文摘Arabidopsis thaliana(A.thaliana)has long been a model species for dicotyledon study,and was the first flowering plant to get its genome completed sequenced[1].Although most wild A.thaliana are collected in Europe,several studies have found a rapid A.thaliana west-east expansion from Central Asia[2].The Qinghai-Tibet Plateau(QTP)is close to Central Asia and known for its high alti-
基金The study was supported by grants from the National Natural Science Foundation of China(31671206 and 81873924)Key Laboratory of Extreme Environmental Medicine,the Ministry of Education(KL2019GY011).
文摘High-altitude cerebral edema(HACE)is a potentially fatal encephalopathy associated with a time-dependent exposure to the hypobaric hypoxia of altitude.The formation of HACE is affected by both vasogenic and cytotoxic edema.The over-activated microglia potentiate the damage of blood-brain barrier(BBB)and exacerbate cytotoxic edema.In light with the activation of microglia in HACE,we aimed to investigate whether the over-activated microglia were the key turning point of acute mountain sickness to HACE.In in vivo experiments,by exposing mice to hypobaric hypoxia(7000 m above sea level)to induce HACE model,we found that microglia were activated and migrated to blood vessels.Microglia depletion by PLX5622 obviously relieved brain edema.In in vitro experiments,we found that hypoxia induced cultured microglial activation,leading to the destruction of endothelial tight junction and astrocyte swelling.Up-regulated nuclear respiratory factor 1(NRF1)accelerated pro-inflammatory factors through transcriptional regulation on nuclearfactorkappa B p65(NF-kB p65)and mitochondrial transcription factorA(TFAM)in activated microglia under hypoxia.NRF1 also up-regulated phagocytosis by transcriptional regulation on caveolin-1(CAV-1)and adaptorrelated protein complex 2 subunit beta(AP2B1).The present study reveals a new mechanism in HACE:hypoxia over-activates microglia through up-regulation of NRF1,which both induces inflammatory response through transcriptionally activating NF-kB p65 and TFAM,and enhances phagocytic function through up-regulation of CAV-1 and AP2B1;hypoxia-activatedmicroglia destroy the integrity of BBB and release pro-inflammatory factors that eventually induce HACE.
基金This work was supported by the National Natural Science Foundation of China(No.61803393)the Natural Science Foundation of Hunan Province(No.2020JJ4751)the Basic Science Research Program through the National Research Foundation(NRF)of Korea funded by the Ministry of Education(No.NRF-2016R1A6A1A03013567).
文摘This letter presents a systematic approach to estimate the annual energy production(AEP) of variable-speed wind turbines erected at high-altitude sites. Compared with the existing empirical-model based approaches, the proposed approach models the influence of the air density on the power production while employing the theoretical power curve. Consequently, the proposed approach provides a precise estimation of AEP, which can serve as a foundation of the optimum turbinesite matching design at different-altitude sites.
文摘Can a planned merger bring two loss-making Shanghai air carriers back to life?By pursuing a merger with Shanghai Airlines Corp. Ltd., the struggling air travel giant China Eastern Airlines Corp. Ltd. is injecting some steam into what looks to be a languid season.
文摘In this study,we investigated the motion,shape,and delayed radiation intensity of a radioactive cloud by establishing a volume-source model of delayed radiation after high-altitude nuclear explosions.Then,the spatial distribution of electron number density at different moments on the north side of the explosion point generated by delayed γ-rays and delayed β-rays from the radioactive cloud under the influence of the geomagnetic field was calculated by solving chemical reaction kinetics equations.The impact of radio communication in the different frequency bands on the process of atmospheric ionization was also studied.The numerical results of the high-altitude nuclear explosion (120 km high and with a 1 megaton equivalent at 40°N latitude) indicated that the peak of electron number density ionized delayed γ-rays is located at a height of approximately 100 km and that of electron number density ionized delayed β-rays is about 90 km high.After 1 min of explosion,the radio communication in the medium frequency (MF) and high-frequency (HF)bands was completely interrupted,and the energy attenuation of the radio wave in the very high-frequency (VHF)band was extremely high.Five minutes later,the VHF radio communication was basically restored,but the energy attenuation in the HF band was still high.After 30 min,theVHF radio communication returned to normal,but its influence on the HF and MF radio communication continued.
