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This study investigates eastward-moving summer heavy rainfall events in the lower reaches of the Yangtze River (LRYR), which are associated with the Tibetan Plateau (TP) vortices. On the basis of rainfall data from gauges and additional atmospheric data from ERA-Interim, the dynamic and thermodynamic effects of moisture transport and diabatic heating are estimated to determine the physical mechanisms that support the eastward-moving heavy rainfall events. As the rainband moves eastward, it is accompanied by anomalous cyclonic circulation in the upper and middle troposphere and enhanced vertical motion throughout the troposphere. In particular, the rainfall region is located in the fore of the upperlevel trough, which is ideal for baroclinic organization of the convective system and further development of the eastwardmoving vortex. The large atmospheric apparent heat source (Q1) also contributes for lifting the lower-level air into the upper atmosphere and for enhancing the low-level convective motion and convergence during the heavy rainfall process. Piecewise potential vorticity inversion further verifies the crucial role that the diabatic heating played in developing the anomalous geopotential height favorable for the enhanced rainfall. The combined action of the dynamic and thermodynamic processes, as well as the rich moisture supply from the seas, synergistically sustained and enhanced the eastwardmoving rainfall. [ABSTRACT FROM AUTHOR]

The Upper Weihe River (UP‐WHR) basin is located along the northeastern Tibetan Plateau. With the northeastward expansion of the Tibetan Plateau since the late Cenozoic, it has involved foreland propagation and undergone obvious surface uplift. In order to determine the latest differential rock uplift and river incision, longitudinal profiles for 12 major tributaries of the UP‐WHR were extracted. Among them, 11 tributaries display uneven profiles with “slope‐break” knickpoints, suggesting that they are in a transient state and that the change in base level caused by tectonic forces may respond to the channel evolution. In addition, channel steepness index (ksn) was calculated to detect the spatial variations of the rock uplift rate. The results show that the north margin of West Qinling (WQL) and the south Liupan Shan (LPS) areas have a high uplift rate. Reconstruction of the paleochannel indicates that the Weihe River has an average incision of 354 ± 130 m since it formed, and the south tributaries have a higher incision of 144 ± 25 m than the north. An average river erosion rate of 0.25–0.3 m/ka was estimated, the WQL has a higher erosion rate of 0.1–0.12 m/ka than Longzhong Basin and the south LPS. This uplift and river incision can be correlated to the northeastward growth of the Tibetan Plateau since the late Cenozoic. [ABSTRACT FROM AUTHOR]

Mutational changes in p53 correlate well with tumorigenesis. Remarkably, however, relatively little is known about the role that p53 variations may play in environmental adaptation. Here we report that codon asparagine-104 (104N) and glutamic acid-104 (104E), respectively, of the p53 gene in the wild zokor (Myospalax baileyi) and root vole (Microtus oeconomus) are adaptively variable, meeting the environmental stresses of the Tibetan plateau. They differ from serine-104 (104S) seen in other rodents, including the lowland subterranean zokor Myospalax cansus, and from serine 106 (106S) in humans. Based on site-directed mutational analysis in human cell lines, the codon 104N variation in M. baileyi is responsible for the adaptive balance of the transactivation of apoptotic genes under hypoxia, cold, and acidic stresses. The 104E p53 variant in Microtus oeconomus suppresses apoptotic gene transactivation and cell apoptosis. Neither 104N nor 104E affects the cell-cycle genes. We propose that these variations in p53 codon 104 are an outcome of environmental adaptation and evolutionary selection that enhance cellular strategies for surviving the environmental stresses of hypoxia and cold (in M. baileyi and M. oeconomus) and hypercapnia (in M. baileyi) in the stressful environments of the Qinghai-Tibet plateau. [ABSTRACT FROM AUTHOR]

Background and aims: The warming of the planet in recent decades has caused rapid, widespread permafrost degradation on the Qinghai-Tibet Plateau. These changes may significantly affect soil moisture content and nutrient supply, thereby affecting ecosystem structure and function. This study aimed to describe the dynamic changes in thaw depth, assess the relationship between thaw depth and soil moisture content, and analyze the changes in species composition and water-use efficiency in response to permafrost degradation. Methods: We surveyed species composition, thaw depth, ground temperature, soil moisture, nutrient content, and foliar stable carbon isotope compositions to gain insights into the response of alpine grassland ecosystems to permafrost degradation on the Qinghai-Tibet Plateau. Results: Moisture content of the surface layer decreased with increasing thaw depth. The correlation between thaw depth and surface soil moisture content was strongest in June and decreased in July and August. The strongest correlation occurred at a depth of 20 cm to 30 cm. The dominant species shifted from Cyperaceae in alpine meadow to mesoxerophytes in alpine steppe before finally shifting to xerophytes in alpine desert steppe. Thaw depth correlation was significantly negative with organic C content ( r = −0.49, P < 0.05) and with total N content ( r = −0.62, P < 0.01). The leaf δC of Carex moorcroftii increased with increasing thaw depth and followed a linear relationship ( R = 0.85, P = 0.008). Conclusions: Permafrost degradation decreases surface soil moisture and soil nutrient supply capacity. Increasing permafrost degradation decreases the number of plant families and species, with hygrophytes and mesophytes gradually replaced by mesoxerophytes and xerophytes. The water-use efficiency of plants improved in response to increasing water stress as surface layers dried during permafrost degradation. Permafrost on the Qinghai-Tibetan Plateau is expected to further degrade as global warming worsens. Therefore, more attention should be dedicated to the response of alpine ecosystems during permafrost degradation. [ABSTRACT FROM AUTHOR]