Tibetan Plateau

青藏高原
  • 文章类型: Journal Article
    偏远地区通常被认为是远距离运输污染物的受体。监测站是调查偏远地区大气环境的重要平台。然而,这些站点周围非常本地的来源的潜在贡献可能会对其大气环境产生重要影响,这仍然是很少研究。在这项研究中,在典型的远程站(NamCo站)和青藏高原(TP)附近的其他地点同时调查了主要的降水离子-世界上所谓的“第三极”。结果表明,尽管与其他偏远地区相比,数值较低,NamCo站降水中主要离子的浓度(例如,Ca2+:32.71μeq/L;[公式:见正文]:1.73μeq/L)显著高于在约2.2Km处的位置处的那些(Ca2+:11.47μeq/L;[公式:见正文]:0.64μeq/L)。这提供了直接证据,表明NamCo站的大气环境受到地表土壤排放的矿物粉尘和污染物以及站本身的人为污染物的显着影响。因此,站上报告的其他相关数据的数量受到影响。例如,应高估NamCo站报告的气溶胶浓度和一些人为污染物。同时,建议在远程站选择监测大气环境的地点时要谨慎,以减少本地来源的潜在影响。
    Remote region is normally considered a receptor of long-range transported pollutants. Monitoring stations are important platforms for investigating the atmospheric environment of remote regions. However, the potential contribution of very local sources around these stations may produce important influences on its atmospheric environment, which is still barely studied. In this study, major ions of precipitation were investigated simultaneously at a typical remote station (Nam Co station) and other sites nearby on the Tibetan Plateau (TP) - the so-called \"The Third Pole\" in the world. The results showed that despite low values compared to those of other remote regions, the concentrations of major ions in precipitation of Nam Co station (e.g., Ca2+: 32.71 μeq/L; [Formula: see text]: 1.73 μeq/L) were significantly higher than those at a site around 2.2 Km away (Ca2+: 11.47 μeq/L; [Formula: see text]: 0.64 μeq/L). This provides direct evidence that atmospheric environment at Nam Co station is significantly influenced by mineral dust and pollutants emitted from surface soil and anthropogenic pollutants of the station itself. Therefore, numbers of other related data reported on the station are influenced. For example, the aerosol concentration and some anthropogenic pollutants reported on Nam Co station should be overestimated. Meanwhile, it is suggested that it is cautious in selecting sites for monitoring the atmospheric environment at the remote station to reduce the potential influence from local sources.
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  • 文章类型: Journal Article
    商业脱氯加(DP)混合物中的两种主要结构异构体,反DP和syn-DP,在土壤中通常表现出不同的解吸和分配效率,这可能与他们不同的衰老速度有关。然而,尚未全面研究控制老化程度的分子参数及其对DP异构体发生的相关影响。在这项研究中,测量了抗DP的快速解吸浓度(Rrapid)的相对丰度,syn-DP,抗Cl11-DP,抗Cl10-DP,Dechlorane-604(Dec-604),和Dechlorane-602(Dec-602)位于青藏高原地理上孤立的垃圾填埋场。Rraid值被用作老化程度的指标,与去氯烷系列化合物的分子的三维构象密切相关。这一观察表明,平面分子可能更倾向于在有机物质的凝聚相中积累,并经历更快速的老化。发现抗DP的分数丰度和脱氯产物主要受DP异构体的老化程度控制。多元非线性回归模型表明,抗CP和syn-DP之间的老化差异主要由总解吸浓度和土壤有机质含量驱动。衰老在DP异构体的运输过程和代谢中起着重要作用,应考虑到对其环境行为的评估。
    Two major structural isomers in commercial dechlorane plus (DP) mixtures, anti-DP and syn-DP, generally displayed varied desorption and partitioning efficiencies in soils, which may be linked to their different aging rates. However, the molecular parameters that govern the degree of aging and its associated effects on the occurrence of DP isomers have not been comprehensively investigated. In this study, the relative abundance of rapid desorption concentration (Rrapid) was measured for anti-DP, syn-DP, anti-Cl11-DP, anti-Cl10-DP, Dechlorane-604 (Dec-604), and Dechlorane-602 (Dec-602) at a geographically isolated landfill area in the Tibetan Plateau. The Rrapid values were used as an indicator of aging degree, exhibiting a close correlation with the three-dimension conformation of the molecules for the dechlorane series compounds. This observation suggested that planar molecules may have a greater tendency to accumulate in the condensed phase of organic matter and undergo more rapid aging. The fractional abundances and dechlorinated products of anti-DP were found to be predominantly controlled by the aging degree of DP isomers. The multiple nonlinear regression model indicated that differences in aging between anti-CP and syn-DP were primarily driven by the total desorption concentration and soil organic matter content. Aging plays a significant role in both the transport processes and metabolism of DP isomers and should be taken into account to refine the assessment of their environmental behaviors.
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  • 文章类型: Case Reports
    背景:可逆性后部脑病综合征(PRES)是一种可逆性血管源性脑水肿,伴有急性神经系统症状。这是一种罕见但严重的疾病,会影响中枢神经系统。PRES是急性链球菌性肾小球肾炎(APSGN)的罕见并发症。高海拔可以通过增加脑血流量(CBF)来加速血管源性脑水肿,损害大脑自动调节和促进血管炎症。我们报告了在高海拔环境下由急性链球菌性肾小球肾炎诱发的PRES病例。
    方法:一名14岁的藏族女孩出现进行性头痛伴血尿,面部肿胀,头晕和呕吐2周,以及多次发作的强直阵挛性癫痫发作14小时。根据实验室检查和临床症状,她被诊断为APSGN。脑磁共振成像(MRI)和计算机断层扫描(CT)显示双侧额叶,与PRES的放射学诊断相符的顶叶和枕骨病变。治疗包括抗生素(青霉素),一种抗癫痫药,高压氧(HBO)治疗。入院后1周获得的随访MRI和入院后4周和6周获得的CT显示脑部病变完全消退。
    结论:该病例说明了青藏高原一名14岁儿童在APSGN后罕见发生PRES。高海拔地区的低氧条件可能会降低大脑自动调节阈值并放大内皮炎症反应,从而在APSGN患者中诱导PRES。认识到PRES的临床和放射学特征很重要,在高海拔地区,HBO辅助治疗可以促进这种情况的快速恢复。
    BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a disorder of reversible vasogenic brain oedema with acute neurologic symptoms. It is a rare but serious disease that affects the central nervous system. PRES is a rare complication of acute post-streptococcal glomerulonephritis (APSGN). High altitude can accelerate vasogenic brain oedema by increasing cerebral blood flow (CBF), impairing cerebral autoregulation and promoting vascular inflammation. We report a case of PRES induced by acute post-streptococcal glomerulonephritis in a high-altitude environment.
    METHODS: A fourteen-year-old Tibetan girl presented with progressive headache with haematuria, facial swelling, dizziness and vomiting for 2 weeks as well as multiple episodes of tonic-clonic seizures for 14 h. She was diagnosed with APSGN based on laboratory tests and clinical symptoms. Brain magnetic resonance imaging (MRI) and computed tomography (CT) revealed bilateral frontal, parietal and occipital lesions that were compatible with the radiological diagnosis of PRES. The treatments included an antibiotic (penicillin), an antiepileptic drug, and hyperbaric oxygen (HBO) therapy. Follow-up MRI obtained 1 week after admission and CT obtained 4 weeks and 6 weeks after admission demonstrated complete resolution of the brain lesions.
    CONCLUSIONS: The case illustrates a rare occurrence of PRES following APSGN in a 14-year-old child in the Tibetan Plateau. The hypoxic conditions of a high-altitude setting might lower the cerebral autoregulation threshold and amplify the endothelial inflammatory reaction, thus inducing PRES in patients with APSGN. It is important to recognize the clinical and radiologic features of PRES, and adjuvant HBO therapy can promote rapid recovery from this condition in high-altitude areas.
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  • 文章类型: Journal Article
    Dust aerosol, one of the important light-absorbing impurities in snow and ice sheets in the Tibet Plateau (TP), can significantly affect the magnitude and timing of snow melting and glacier recession by altering the surface albedo. It is thus of great importance to understand the potential source and transport mechanism of the dust aerosol over the TP. A typical dust storm case, erupted from the Thar Desert (ThD) in South Asia on 1 to 4 May 2018, was selected to understand synoptic causes and a transport mechanism to the TP using the latest Second Modern-Era Retrospective analysis for Research and Applications (MERRA-2) reanalysis data. Comparing with active/passive satellite-based and AERONET-based observations, the MERRA-2 data provide both the spatio-temporal distribution and evolution process of the dust aerosol more accurately. This study also found that the entire Indian-Gangetic Plain (IGP), Southern India, the Bay of Bengal, and even the TP were influenced by the dust event. The synoptic analysis showed that the dust storm was caused jointly by an upper-level jet stream (ULJS), an upper trough and the subtropical high. A typical south-north secondary circulation adjacent its exit zone, mainly triggered by the ULJS, promoted much stronger and higher vertical uplift of the dust aerosols over the ThD. Consequently, those uplifted dust particles were easily transported to the TP across the majestic Himalayas by the southerly airflows in front of the low-pressure trough over Afghanistan and the southern branch trough over the Bengal Bay. These results indicate that dust aerosol and anthropogenic pollutions constrained and driven by the typical atmospheric circulation condition from South Asia are likely to be transported to the TP. Therefore, it is necessary to further pay attention to the influence of dust aerosols from South Asia on the weather and climate in the TP and its downstream areas.
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  • 文章类型: Journal Article
    在鱼道入口处吸引鱼类对于确保鱼类通行效率至关重要,这就需要考虑鱼的游泳特性。本案例研究的目的是提出青藏高原大坝下游的优化水流条件,以吸引鱼类进入鱼道。Cyprinidae的六种当地特有物种:Schizothoracinae被认为是保护目标。然而,高原上大多数特有鱼类的游泳能力尚不清楚,在这方面没有以前的项目可以作为参考。因此,首先根据三个指标测试目标物种的游泳性能,感应速度,临界游泳速度和爆裂游泳速度,根据测试结果,通过不同的流速阈值对六个行为区进行了分类。然后采用经过验证的3D水动力模型对四种典型水库运行场景下大坝下游的流场进行了模拟。通过将模拟的流场与不同的行为区域相匹配,评估所有方案的目标鱼类的通过性,结果表明,在每种情况下都会有不同的潜在迁移路线。对于鱼类通道季节最常见的情况,建议对称使用涡轮机T1和T6,以便与当前状态相比,鱼道入口附近的流速较低,湍流强度较低。此外,建议在具有高潜力的迁徙路线上增加新的入口,以增加鱼类进入的机会。除了为这种具体情况提供解决方案之外,这项研究丰富了有关青藏高原特有鱼类游泳特征的知识。此外,这项研究提供了一种可能的技术方法,在确定类似鱼类通道项目中的吸引流量时,将鱼类行为特征和水力指标相结合。
    Attracting fish at fishway entrances is vital for ensuring fish passage efficiency, which requires consideration of the swimming characteristics of fish. The objective of this case study was to propose optimized flow conditions downstream of a dam on the Tibetan Plateau to attract fish into fishways. Six local endemic species of Cyprinidae: Schizothoracinae were considered as protection targets. However, the swimming abilities of most endemic fishes on the plateau remain unclear, and no previous projects in this area could serve as a reference. Thus, the swimming performances of the target species were first tested based on three indexes, induction velocity, critical swimming speed and bursting swimming speed, and six behavior zones were classified by different flow velocity thresholds based on the test results. A verified 3D hydrodynamic model was then adopted to simulate the flow field downstream of the dam under four typical reservoir operation scenarios. By matching the simulated flow fields to the different behavior zones, all scenarios were assessed for the passability of the target fishes, and the results showed that there would be different potential migration routes under each scenario. For the most common scenario during the fish passage season, symmetrical use of turbines T1 and T6 was recommended so that the flow would be lower velocity and the turbulence would be less intense near the fishway entrances than the current regime. Moreover, the addition of a new entrance was suggested on the migration routes with high potential use to increase the chance that fish would enter. Beyond providing a solution for this specific case, this study enriches knowledge about the swimming features of endemic fishes on the Tibetan Plateau. Furthermore, this research provides a possible technical methodology that combines fish behavioral characteristics and hydraulic indexes when determining attraction flows in similar fish passage projects.
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  • 文章类型: Case Reports
    A 54 years old male patient with chronic leg ulcers was admitted in our hospital in November 2017. He was diagnosed as pyoderma gangrenosum by the pathological examination. Then the wound was treated with simple vacuum sealing drainage combined with irrigation of oxygen loaded fluid. This therapy overcame the shortage of hypoxia in the Tibetan Plateau on wound healing, resulting in a better wound healing. The patient was eventually cured and discharged from hospital.
    笔者单位于2017年11月收治1例54岁男性下肢慢性溃疡患者,入院经病理检查确诊为坏疽性脓皮病。采用简易负压封闭引流联合含氧液冲洗治疗创面,克服高原低气压缺氧对创面愈合带来的不利影响,促进创面愈合,患者最终痊愈出院。.
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  • 文章类型: Journal Article
    如今,山区的重力数据空白通常由机载重力测量的数据填充。由于机载重力仪传感器造成的误差,由于恶劣的飞行条件,这种错误不能完全消除。机载重力法产生的重力干扰的精度约为3-5mgal。使用机载重力分析法的主要障碍是由向下延续引起的误差。为了提高外部高精度重力信息的结果,例如,从表面数据可用于高频校正,而卫星信息可以应用于低频校正。表面数据可用于减少系统误差,而正则化方法可以减少向下延续的随机误差。空中重力测量有时在山区进行,世界上这种类型的测量最极端的地区是青藏高原。由于该区域没有高精度的表面重力数据,不能使用上述涉及外部重力数据的误差最小化方法。我们提出了一种结合正则化的半参数向下延拓方法来抑制青藏高原的系统误差效应和随机误差效应;即无需使用外部高精度重力数据。我们使用美国国家海洋和大气管理局(NOAA)的路易斯安那州空中重力数据集证明了新方法的有效性。此外,对于青藏高原,我们表明也使用合成地球重力模型2008(EGM08)衍生的重力数据成功进行了数值实验。该方法产生的估计系统误差接近模拟值。此外,我们研究了向下延续高度与误差效应之间的关系。分析结果表明,所提出的半参数方法与正则化相结合可以有效地解决此类建模问题。
    Gravity data gaps in mountainous areas are nowadays often filled in with the data from airborne gravity surveys. Because of the errors caused by the airborne gravimeter sensors, and because of rough flight conditions, such errors cannot be completely eliminated. The precision of the gravity disturbances generated by the airborne gravimetry is around 3-5 mgal. A major obstacle in using airborne gravimetry are the errors caused by the downward continuation. In order to improve the results the external high-accuracy gravity information e.g., from the surface data can be used for high frequency correction, while satellite information can be applying for low frequency correction. Surface data may be used to reduce the systematic errors, while regularization methods can reduce the random errors in downward continuation. Airborne gravity surveys are sometimes conducted in mountainous areas and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic errors generated by the method are close to the simulated values. In addition, we study the relationship between the downward continuation altitudes and the error effect. The analysis results show that the proposed semi-parametric method combined with regularization is efficient to address such modelling problems.
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