特高高原藏族农牧民HBsAg阳性率调查

目的评估生活在特高高原(海拔4 500米以上)极限环境的藏族农牧民的HBsAg携带状况。方法回顾性分析2014年至2015年岗巴县接受免费体检的藏族农牧民体检手册和县医院检验科患者登记册,调取HBV血清标志物(HBV-M)或单项HBsAg的检测结果,进行统计分析。结果岗巴县5个乡镇的自愿接受体检的904名藏族农牧民中,HBsAg阳性率为20.0%(95%CI:17.4%~22.6%),5个乡镇HBsAg阳性率从14.1%到30.0%。县医院299例门诊患者的HBsAg阳性率为24.7%(95%CI:22.3%~32.5%),而299例住院患者HBsAg阳性率为26.4%(95%CI:21.4%~31.4%)。在县医院进行过HBV-M检测的181例患者中,58.6%(95%CI:51.4%~65.8%)显示为HBV-M全阴性。结论岗巴藏族农牧民HBsAg携带率高,且乙型肝炎疫苗保护率低下,提示对特高高原农牧民这一特殊人群的HBV感染状况需要关注。

特高高原低氧环境短期暴露对电网建设人员血常规、肝功能、肾功能等指标变化影响的研究报告

本研究旨在探讨电网建设人员在特高高原低氧环境中的生理变化情况,并分析血常规、肝功能、肾功能等指标的变化。研究采用横断面研究设计,选取2019年8月至2020年7月在海拔4500米以上特高高原执行短期电网建设任务的200名工人为观察组,并随机选择200名常驻平原地区的人群作为对照组。观察组根据年龄分为A组(18-29岁)、B组(30-39岁)、C组(40-49岁)和D组(≥50岁),对照组分别为I组(18-29岁)、II组(30-39岁)、III组(40-49岁)和IV组(≥50岁)。研究人员采集并检测了参与者的血常规、肝功能、肾功能等指标。研究结果表明,电网建设人员在特高高原低氧环境中的生理指标发生了显著变化,这些变化与在高原作业时间和海拔高度呈正相关关系。血常规指标中,红细胞计数、血红蛋白、红细胞压积等增加,血小板计数也明显增加。肝功能指标中,谷丙转氨酶、谷草转氨酶等增加。肾功能指标中,血尿酸也有显著变化。这些变化可能是机体对高原环境的低氧适应反应所致。因此,特高高原低氧环境对电网建设人员的健康产生了重要影响,需要采取相应的预防和保健措施。

海拔5000米以上高原驻训官兵疾病谱临床分析

通过分析驻海拔5000~5500米某部官兵的常见疾病谱,为搞好特高高原驻训的卫生防病工作提供参考。方法 收集2020年6月1日~8月31日,驻海拔5000~5500米某部官兵所发1845例次的病例,回顾性分析疾病构成。结果 疾病系统构成排名前5位的分别是呼吸系统疾病、急性高原病、消化系统疾病、运动系统疾病、神经与感觉器官疾病;常见疾病发生率排名前10位的分别是急性上呼吸道感染、急性气管支气管炎、急性高原反应、高原肺水肿、急性腹泻、软组织损伤、日光性皮炎、牙周炎、眼干燥症、高血压病。结论 呼吸系统疾病、消化系统疾病仍是海拔5000米以上特高高原卫生防病的重点,急性高原病防控也不容小觑,高原病防治常识仍需进一步普及,另外,眼、耳鼻喉、口腔、皮肤病等小专业疾病也比较常见,需要积极防治。

Mapping the vegetation distribution of the permafrost zone on the Qinghai-Tibet Plateau

In this paper, an updated vegetation map of the permafrost zone in the Qinghai-Tibet Plateau （QTP） was delineated. The vegetation map model was extracted from vegetation sampling with remote sensing （RS） datasets by decision tree method. The spatial resolution of the map is 1 km×1 kin, and in it the alpine swamp meadow is firstly distinguished in the high-altitude areas. The results showed that the total vegetated area in the permafrost zone of the QTP is 1,201,751 km2. In the vegetated region, 50,260 km2 is the areas of alpine swamp meadow, 583,909 km2 for alpine meadow, 332,754 km2 for alpine steppe, and 234,828 km2 for alpine desert. This updated vegetation map in permafrost zone of QTP could provide more details about the distribution of alpine vegetation types for studying the vegetation mechanisms in the land surface processes of highaltitude areas.

A Method for Alpine Wetland Delineation and Features of Border: Zoigê Plateau, China

Accurate wetland delineation is the basis of wetland definition and mapping, and is of great importance for wetland management and research. The Zoige Plateau on the Qinghai-Tibet Plateau was used as a research site for research on alpine wetland delineation. Several studies have analyzed the spatiotemporal pattern and dynamics of these alpine wetlands, but none have addressed the issues of wetland boundaries. The objective of this work was to discriminate the upper boundaries of alpine wetlands by coupling ecological methods and satellite observations. The combination of Landsat 8 images and supervised classification was an effective method for rapid identification of alpine wetlands in the Zoig6 Plateau. Wet meadow was relatively stable compared with hydric soils and wetland hydrology and could be used as a primary indicator for discriminating the upper boundaries of alpine wetlands. A slope of less than 4.5° could be used as the threshold value for wetland delineation. The normalized difference vegetation index （NDVI） in 434 field sites showed that a threshold value of 0.3 could distinguish grasslands from emergent marsh and wet meadow in September. The median normalized difference water index （NDWI） of emergent marsh remained more stable than that of wet meadow and grasslands during the period from September until July of the following year. The index of mean density in wet meadow zones was higher than the emergent and upland zones. Over twice the number of species occurred in the wet meadow zone compared with the emergent zone, and close to the value of upland zone. Alpine wetlands in the three reserves in 2014 covered 1175.19 kin2 with a classification accuracy of 75.6%. The combination of ecological methods and remote sensing technology will play an important role in wetland delineation at medium and small scales. The correct differentiation between wet meadow and grasslands is the key to improving the accuracy of future wetland delineation.

The Relationship Between Vegetation Characteristics and Altitudes in Transitional Permafrost Zone in Xidatan, Qinghai-Tibetan Plateau

Many studies showed that permafrost has profound influence on alpine ecosystem. However, former researches were mainly focused on typical points by temporal scales. There were few studies about the correlation between vegetation characteristics and different altitudes covering a large region in spatial pattern, especially in transitional permafrost(TP). There were continuous permafrost(CP) discontinuous permafrost(DCP) and seasonal frozen ground(SFG) in this study region. The types of permafrost changed from SFG to DCP, and finally become CP as the altitudes of Xidatan increase. In this paper, 112 845 points interpreted by HJ1-B(environment and disaster monitoring and prediction small satellite constellation), vegetation investigation points, thawing layer thickness research sites, ground temperature and water content observation plots were used to examine the spatial pattern of vegetation which were located in different altitudes in Xidatan, a typical TP region, in Qinghai-Tibetan Plateau. Vegetation characteristics, soil moisture content(SMC) and thaw depths were collected in 15 August to 25 August2012. Characteristics of vegetation were mainly represented by fractional vegetation cover(FVC) derived from the normalized difference vegetation index(NDVI), as well as above ground biomass(AGB). In this paper, we analyzed that the distinction of vegetation characteristics in each range through statistics data. These ranges were divided by varied altitudes. For examples, the ranges were divided into 50 m or 100 m. In this study we use a large area plots method to further discuss the relationship between the features of vegetation and the different regions of permafrost based on altitudes shifts in Xidatan. A diagram described the vegetation characteristics variability with rising altitudes in transitional permafrost region was drawn in this paper. Our results illustrated the FVCs first increased in SFG region and then decreased in DCP zone slowly, and in CP region FVCs soared then dropped dramatically. With the altitudes increased, the curve of FVCs indicated a parabolic distribution except a little difference in the first 200 m range.

Research on Crustal Flow and Its Dynamic Characteristics in Sichuan and Its Adjacent Area

Using the broadband seismic data of the regional stations in the Sichuan Digital Seismic Network and the mobile seismic stations in this region,the receiver function inversion method was adopted to study the characteristics of crustal flow and dynamic effects in Sichuan and adjacent areas. The results show that: Velocity in the crust and upper mantle of the Sichuan basin is significantly higher than that beneath the eastern margin of the Qinghai-Tibetan plateau. The velocity v_S is from 3. 6 to 3. 8km / s in the crust and4. 5- 4. 8km / s in the upper mantle beneath the basin,and there is no low-velocity layer in the crust. The lithology shows a hard block. The v_S velocity in the eastern margin of the Qinghai-Tibetan plateau is lower,with average v_Sof 3. 0- 3. 4km / s in the mid crust and4. 0- 4. 5km / s in the upper mantle. Low-velocity layers are distributed widely in the crust,most of which are in the mid crust at a depth of 20km- 40 km,and there are also a few low-velocity layers appearing in the upper crust at depths of 10km- 20 km and the lower crust at depths of 40km- 60 km. Affected by the northward pushing of the Indian plate,the eastward movement of the eastern margin of the Qinghai-Tibetan plateau is blocked by the hard Sichuan basin,producing a southward and southeastward component.Such movement process is produced by the complicated forces acting in this area. Just under the action of these forces, the eastern margin of the Qinghai-Tibetan plateau becomes a region with complicated geology and intensive earthquake activity. Obstructed by the hard Sichuan basin,the low-velocity crustal flow is delaminated and split into two or three upward and downward tributaries. The upward flow intruded into the upper crust,causing uplift of the earths urface,forming mountain crests; the downward flow intruded into the lower crust and upper mantle,resulting in thickening of the crust and depression of the Moho. The crustal flow in the eastern margin of the Qinghai-Tibetan plateau is mainly distributed along the active faults. The crustal flow flows out from the Qiangtang block in the middle part of the eastern margin of the Qinghai-Tibetan plateau,the mainstream flows along the NW-SE trending Xianshuihe fault zone,then turns NS and flows to the south along the Anninghe and Xiaojiang faults. There is another crustal flow in the north of the study area,flowing in the NE and E-W directions to the Longmenshan faults.

Thermokarst lake changes between 1969 and 2010 in the Beilu River Basin, Qinghai–Tibet Plateau, China

This work presents changes of thermokarst lakes from Beilu River Basin on the Qinghai-Tibet Plateau over the past four decades （1969-2010） using aerial and satellite image interpretation. The results indicated that thermokarst lake activity had generally increased rapidly between 1969 and 2010. The number of thermokarst lakes had increased by approximately 534, and their coverage expanded by about 410 ha. The two main changes observed were an increase in the number of small lakes and the expansion of larger lakes. These changes are likely the result of persistent climate warming and a gradually increasing imbalance between precipitation and evapotranspiration （PET）. However, some non-climatic factors, such as the lake-bottom substrate and local engineering activities, have also influenced the lake changes. If air temperature and P-ET continue to rise, the number of thermokarst lakes and the area they cover may continue to increase in the future.