Search Results (2,907)

Abies georgei var. smithii (Viguie & Gaussen) is a dominant conifer along the southeastern margin of the Qinghai–Tibet Plateau, where heart rot often develops covertly, complicating forest health monitoring and disease management. Fomitopsis subpinicola B.K. Cui, M.L. Han & Shun Liu is an important causal agent of heart rot affecting A. georgei var. smithii in this region, yet rapid, field-deployable molecular diagnostics of this pathogen remain limited. Here, we developed and evaluated two TEF1α-based isothermal platforms for specific detection of F. subpinicola: RAA and LAMP. To reduce potential cross-reactivity, TEF1α sequences from representative taxa within the F. pinicola species complex and closely related non-complex species were aligned for primer/probe design. Candidate RAA primers were screened by gel electrophoresis to select an optimal pair, and two LAMP primer sets were compared by specificity testing to identify the best-performing set. Both assays specifically detected F. subpinicola with no cross-amplification in the tested non-target fungi. Limits of detection were 9.97 copies/μL for fluorescent RAA (25 min), 9.97 × 10² copies/μL for RAA-LFD (15 min), and 9.97 × 10³ copies/μL for LAMP (35 min). In 30 increment core samples from A. georgei var. smithii, all methods consistently detected samples with obvious decay, while fluorescent RAA additionally yielded positives in some apparently asymptomatic samples, indicating promise for early or low-abundance screening. Together, these assays constitute a tiered and application-oriented detection system, enabling flexible selection of diagnostic approaches according to sensitivity requirements, operational conditions, and field surveillance needs for heart rot of A. georgei var. smithii. Full article

Deep learning has significantly improved landslide identification from remote sensing imagery, but accurately detecting multi-scale landslides under complex backgrounds remains challenging. This study proposes a lightweight YOLOv8-based model, namely YOLO-BEG, incorporating three improvements: a bidirectional feature pyramid network (BiFPN) for enhanced multi-scale feature fusion, an embedded Gaussian attention system (EGS) to improve discrimination under complex backgrounds, and a generalized intersection over union (GIoU) loss to optimize boundary localization. The model was evaluated on two datasets: a vegetation-covered Southwest landslide database and the Sichuan–Tibet Highway database. On the Southwest database, YOLO-BEG improved Precision, Recall, and F1-score by 16%, 13%, and 15% compared with YOLOv8, while using only one tenth of the parameters of Mask R-CNN. In the Sichuan–Tibet Highway database, which has more diverse background conditions, YOLO-BEG outperformed Mask R-CNN and Faster R-CNN by 32% and 13% in F1-score, respectively. These results demonstrate that YOLO-BEG is able to operate with fewer parameters and yield high-precision identification of landslides with different scales under complex backgrounds, making it a rapid and accurate tool for landslide identification. Full article

Wuweiganlu (WGL) is a traditional formulation widely applied in the treatment of rheumatoid arthritis (RA), yet the identity of its bioactive constituents remains inadequately defined. In this study, ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and untargeted serum metabolomics were employed to characterize the active components of WGL. Fraxin was identified as a principal compound from WGL. To investigate its therapeutic mechanism in RA, a series of in silico and experimental approaches were conducted. Network pharmacology analysis and RNA sequencing identified heat shock protein family member 8 (HSPA8) as a potential molecular target of Fraxin, which was further validated by molecular docking studies. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that Fraxin exerts its effects primarily by modulating cell apoptosis through the PI3K signaling pathway. In vitro experiments demonstrated that Fraxin significantly reduced inflammatory responses and downregulated HSPA8 expression in lipopolysaccharide (LPS)-stimulated fibroblast-like synoviocytes (FLs) and macrophages. In vivo, Fraxin administration markedly reduced paw swelling, alleviated bone deformities, and improved bone volume fraction (BV/TV) in male IL1RA-deficient mice exhibiting spontaneous arthritis. Histological analysis confirmed that Fraxin attenuated joint inflammation by modulating the inflammatory microenvironment. Additionally, Fraxin inhibited synovial hyperplasia by regulating mitochondrial membrane potential collapse in FLs. Functional assays revealed that this regulation occurred via the inhibition of HSPA8/PI3K/AKT signaling axis, thereby suppressing aberrant FLS proliferation and contributing to the attenuation of RA progression. Full article

Accurate prediction of embankment settlement and evaluation of its serviceability in permafrost regions are significantly challenged by scarce monitoring data and dynamic, non-stationary settlement processes. To address this, an integrated framework combining change-point detection with a novel dynamic prediction model is proposed. Analysis of long-term monitoring data from the Qinghai–Tibet Railway using the Pettitt test revealed a key change point around 2015, indicating a transition towards stabilization. Subsequently, an SAA-GRU-LSTM hybrid model, employing a dynamic compensation prediction strategy, was developed. The model successfully utilized only early-stage data to forecast future settlement trends, demonstrating robust performance in adapting to the identified abrupt change. Furthermore, by applying established engineering serviceability criteria to both historical and predicted data, the framework enables a dynamic and prospective serviceability assessment. This methodology provides a practical tool for the maintenance and risk management of infrastructure in permafrost environments under conditions of data scarcity and process uncertainty. Full article

Grain-scale heterogeneity strongly influences hydraulic fracture initiation and trajectory in crystalline rocks, yet its contributions to non-planar growth and the interaction of multiple nearby cracks remain insufficiently quantified. To address this gap, we perform numerical experiments on a model containing two parallel pre-existing cracks using a hydro-mechanical phase-field framework, systematically quantifying how mineral distribution and axial compression govern non-planar hydraulic fracture growth and inter-fracture competition. The results demonstrate that mineral distribution is the primary driver of fracture complexity. Even within the same Voronoi tessellation, redistributing minerals alone yields markedly different trajectories, deflections, branching patterns, and final morphologies. Furthermore, non-planar growth follows a stepwise, energy-threshold-driven mechanism. When cracks penetrate strong grains or undergo large-angle deflections, propagation is impeded, and injection pressure builds up. Once a critical energy threshold is reached, accumulated energy is rapidly released along the path of minimum incremental energy, manifested as abrupt pressure drops and rapid crack advance. Additionally, the two nearby fractures exhibit strong mechanical competition. Despite negligible hydraulic interference in low-permeability granite, early growth of one fracture redistributes stresses and suppresses the driving force of the other, resulting in asymmetric development. Finally, axial compression primarily governs the overall propagation orientation and influences local failure modes but has a limited effect on peak pressure relative to mineral distribution. Full article

The Qinghai–Tibet Plateau is undergoing rapid warming and humidification, with altered precipitation regimes increasingly affecting soil nitrogen cycling and N₂O emissions. Denitrification—a key nitrogen transformation pathway—is particularly sensitive to these hydrological changes. Here, we investigated the response of nirK-type denitrifying microbial communities to altered precipitation in an alpine wetland on the northern shore of Qinghai Lake. Using a long-term precipitation manipulation platform with five gradients (ambient, ±25%, and ±50%), we integrated high-throughput sequencing with bioinformatics to systematically assess community shifts. Short-term precipitation treatments did not significantly alter alpha diversity, but markedly restructured community composition. Extreme wetting (+50%) increased within-group heterogeneity. At the phylum level, Proteobacteria remained dominant across all treatments, whereas extreme drought (−50%) suppressed Planctomycetes. At the genus level, Ochrobactrum was enriched under reduced precipitation, while Rhodopseudomonas increased under increased precipitation. Functional predictions indicated that reduced precipitation enhanced nitrogen fixation potential, whereas increased precipitation favored nitrate respiration. Soil pH and carbon fractions were the key environmental filters driving community variation. Ecological process analysis revealed that community assembly was entirely governed by deterministic processes, specifically variable selection. Together, these findings elucidate how precipitation shifts reconfigure the structure and functional potential of denitrifying microbial communities in alpine wetlands, primarily via changes in soil pH and moisture under variable selection. This work provides critical insights into microbial regulation of the nitrogen cycle on the Tibetan Plateau under ongoing climate change. Full article

Groundwater is a strategic resource for maintaining ecological balance and supporting human development in arid inland basins. However, under the dual pressures of climate change and human activities, it faces threats in both quantity and quality. This study selects the Chahan Usu River watershed in the eastern Qaidam Basin, a typical arid inland basin on the Tibetan Plateau, to assess the current quality of groundwater resources and reveal the formation mechanisms and material sources of its hydrochemistry. The results show that the groundwater in the watershed is generally weakly alkaline, with some areas exhibiting high salinity. The dominant cations and anions are Na⁺ and Cl⁻, respectively. The hydrochemical type is mainly Cl-Na, with a minority being mixed Cl-Mg·Ca. Overall, the groundwater in the watershed is suitable for domestic use. However, in the middle and lower reaches of the Chahan Usu River, nitrate and ammonia nitrogen contamination reduce its suitability. Meanwhile, although long-term use of this groundwater would not lead to soil degradation, its widespread high salinity and high sodium content make it unsuitable for irrigation. Water–rock interactions with evaporites and silicate rocks are the main mechanisms controlling groundwater chemistry in the watershed. Among them, halite minerals contribute most of the Na⁺ and Cl⁻, while sulfate minerals provide Ca²⁺ and SO₄²⁻. In addition, cation exchange is widespread. This study provides a reference for ensuring the security and sustainable development of groundwater resources on the plateau. Full article

Despite the essential role of soil microbial communities in driving nutrient cycling within alpine meadows, their distribution patterns along elevational gradients and their responses to environmental changes remain largely unexplored. To investigate this, soil samples were collected from five elevations (3300–4500 m) in the northeastern Qinghai–Tibet Plateau to analyze bacterial community composition and diversity, as well as their associations with soil physicochemical properties and enzyme activities. The results showed significant variation in bacterial community composition and diversity across elevations. Actinomycetota, Pseudomonadota, and Acidobacteriota were the dominant phyla at all sampling sites. Community diversity, measured by the Shannon index, generally increased with elevation, peaking at 4500 m and lowest at 3300 m. Pearson correlation analysis and redundancy analysis (RDA) indicated that soil bacterial community structure was significantly correlated with both soil nutrient factors and enzyme activities. Among these variables, total potassium, available phosphorus, catalase, and urease were strongly correlated with bacterial community differentiation. In addition, PERMANOVA results showed that elevation was the primary factor driving community variation, explaining a substantial proportion of the variation in community composition at a statistically significant level. Overall, this study highlights the distribution of bacterial communities in alpine meadow soils along an elevational gradient and their environmental associations, providing foundational data for understanding microbial community responses to environmental changes in alpine ecosystems. Full article

Against the backdrop of ongoing climate change, the Qinghai–Tibet Plateau, a region highly sensitive to climatic variation, exhibits intricate spatiotemporal patterns in reference crop evapotranspiration (ET_O), with significant implications for regional water-resource planning. This study selected four agro-climatic zones across the plateau region (TSA, TSH, TAZ, and WCH). Long-term daily observations from 28 meteorological stations were used to estimate ET_O via the FAO 56 Penman–Monteith equation. This extensive dataset enabled robust trend analysis using the Mann–Kendall test, alongside a cloud-model framework, and analyses of sensitivity and contributions to evaluate ET_O’s spatiotemporal evolution, its distributional uncertainty, and the underlying drivers. Results reveal pronounced regional heterogeneity in the interannual variability of ET_O. Annual ET_O declined in TSH and TSA (trend rates of −1.12 and −6.58 mm·10a⁻¹, respectively) and increased in TAZ and WCH (15.76 and 10.74 mm·10a⁻¹, respectively). At monthly and seasonal timescales, ET_O exhibited an unimodal pattern, with the greatest stability in winter and spring and lower stability in summer and autumn. The cloud-model parameter He indicates that ET_O stability is greatest in TSH and weakest in WCH, with He values of 7.15 and 12.29 mm, respectively. Contribution-rate analyses identify T_max and T_mean as the principal determinants of rising ET_O across all study zones, reflecting the largest individual contributions. Temperature-related factors together account for the majority of ET_O variability across the regions, with their absolute contributions ranging from 5.61% to 8.63%, well above those of aerodynamic factors (0.62–1.78%). Stability assessments indicate that ET_O is generally more unstable than its meteorological drivers, with substantial regional disparities, implying that ET_O evolution cannot be explained by a single controlling factor. Overall, the study characterizes the uncertainty in ET_O variations under complex terrain, highlights the value of the cloud model for refined hydrological assessments, and provides a scientific basis for adaptive agricultural water-resource management in the region. Full article

Volatile fatty acids (VFAs), the primary end-products of microbial fermentation in the ruminant forestomach, supply approximately 70% of the host’s energy requirements and play a pivotal role in maintaining energy homeostasis. While the mechanisms governing ruminal VFA production, absorption, and metabolism are well-characterized in common ruminants like dairy and beef cattle, a systematic integration of these processes in yaks, an iconic species long-adapted to the extreme Qinghai–Tibet Plateau, remains incomplete. This review synthesizes current knowledge on the entire VFA pathway in the yak rumen, from production to tissue metabolism. We detail the critical roles of functional microbes, including fibrolytic bacteria and Prevotella, in VFA synthesis and how their activity is dynamically regulated by dietary composition and seasonal shifts. Building on the unique structural features of the yak rumen epithelium, the review analyzes VFA absorption mechanisms involving both passive diffusion and carrier-mediated transport. Furthermore, we systematically outline the metabolic fates and energy partitioning strategies of VFAs across the rumen epithelium, liver, and peripheral tissues. This synthesis aims to elucidate the highly efficient and adaptive physiological basis of VFA metabolism that underpins the yak’s exceptional ability to utilize energy under the low-energy conditions of the high-altitude environment. Ultimately, this work seeks to provide a theoretical foundation for understanding plateau-adapted energy efficiency and to inform precision nutritional strategies for ruminants in alpine regions. Full article

To prepare high-temperature-resistant dielectric composite films, a novel three-dimensional nanofiller was fabricated using carboxylated polyarylene ether nitrile as a bridge, which tightly loads BaTiO₃ nanoparticles onto WS₂ nanosheets (WS₂@BT) via in situ chemical bonding. Afterward, the WS₂@BT nanofiller was introduced into the polyarylene ether nitrile (PEN) matrix, and high-temperature heat treatment was performed to form a crosslinked network, yielding CPEN/WS₂@BT nanocomposites. Notably, the modified WS₂@BT effectively improves the compatibility between the nanoparticles and the PEN matrix, which is superior to the compatibility of unmodified nanofillers with the matrix. Moreover, after crosslinking, CPEN/WS₂@BT exhibits excellent comprehensive performance: when the filler content is 30 wt%, its glass transition temperature (T_g) reaches 257.83 °C, significantly higher than that of PEN/WS₂@BT, and its dielectric constant is 193% higher than that of pure CPEN. In addition, the dielectric temperature coefficient remains below 1 × 10⁻³ °C⁻¹ in the range of 25–220 °C. Overall, this work provides an effective and reliable strategy for preparing high-performance, high-temperature-resistant composite dielectric films. Full article

Semen quality and fecal microbial composition were compared between native Oula rams reared on the Qinghai–Tibet Plateau and Hu sheep rams introduced from lowland regions. Semen quality was analyzed in eight adult Oula rams and eight Hu rams, and fecal microbial composition was assessed via 16S rRNA sequencing. Results indicated that sperm acrosome integrity was significantly higher in Hu sheep than in Oula sheep (p < 0.001); other semen parameters showed no significant differences. Significant differences were also observed in fecal microbial communities between the two breeds. Compared with Hu sheep, Oula sheep exhibited higher microbial abundance and diversity at the phylum level, particularly Campylobacterota, Euryarchaeota, Planctomycetota, Verrucomicrobiota, Myxococcota, and Deferibacterota (p < 0.05). At the genus level, Oula sheep had significantly higher abundances of Treponema, Campylobacter, Methanobrevibacter, UCG-009, Family_XIII_AD3011_group, [Eubacterium]nodatum group, Candidatus Soleaferrea, Akkermansia, and unidentified_Ruminococcaceae (p < 0.05). Correlation analysis indicated associations between sheep semen quality and the top 30 abundant fecal microbial genera. Six genera showed significant positive correlations with acrosome integrity rate, and eight genera exhibited significant negative correlations (p < 0.05). Two genera were correlated positively with plasma membrane integrity rate (p < 0.05). Prevotellaceae_UCG-004 was positively correlated with sperm motility and Progressive Motility spermatozoa proportion (p < 0.05); Ruminococcus showed a significant positive correlation with sperm linear motility and a significant negative correlation with acrosome integrity rate (p < 0.05). These findings indicate that the microbial groups enriched in Oula sheep fecal samples and exhibiting negative correlations with acrosome integrity—including Ruminococcus, Treponema, Akkermansia, and Euryarchaeota—are associated with sperm quality through physiological adaptation mechanisms specific to high-altitude environments. Full article

Well spacing and reinjection rate are two critical parameters controlling the efficiency and sustainability of hot dry rock geothermal development. Taking the Yangbajing geothermal field in Tibet as the geological setting, permeability experiments were conducted on fractured rock masses under multiple operating conditions, and a three-dimensional fully coupled thermo-hydro-mechanical numerical model was established to systematically evaluate the effects of different well spacing–reinjection rate combinations on heat extraction performance. The experimental results show that axial stress is the dominant factor governing specimen deformation and seepage characteristics. Permeability decreases with increasing axial stress, exhibiting an initial sharp decline followed by a gradual reduction. The effect of temperature varies with axial stress level. Under low to moderate axial stress, permeability decreases monotonically with increasing temperature, whereas under high axial stress, it first decreases and then increases. The simulation results indicate that the production temperature remains relatively stable during the early stage of exploitation and subsequently declines, with the rate of decline increasing significantly as the reinjection rate increases or the well spacing decreases. In addition, an exponential positive relationship is identified between well spacing and the optimal reinjection rate. When a 10% decline in production temperature is adopted as the shutdown criterion, the optimal reinjection rate increases from 60 m³/h to 150 m³/h as the well spacing increases from 500 m to 800 m. Based on the simulation results, the theoretical installed capacity of the first deep reservoir in the Yangbajing geothermal field is preliminarily estimated to reach 31.8 MW. Full article

Amid the dual pressures of ecological conservation and livelihood sustainability on the Qinghai–Tibet Plateau, investigating the economic effects of herders’ adaptation strategies holds practical relevance. Focusing on grass-based livestock husbandry, this study examines 327 pastoral households in Xinghai County, Qinghai Province, using endogenous switching regression models to empirically analyze the determinants, economic effects, and underlying mechanisms of herders’ production transformation. The main contribution is providing new empirical evidence for understanding herders’ adaptive strategies and informing policy design. The findings reveal that: (1) Transformation decisions are rational choices shaped by household resource endowments. Households with more labor and larger pasture areas are more likely to transform, while non-pastoral employment partially substitutes for such transformation. (2) Production transformation significantly increases herders’ pastoral income. Under the counterfactual framework, the income enhancement effect amounts to 21,509.08 Yuan for the transformed group and 741.30 Yuan for the non-transformed group. Income growth in the transformed group mainly stems from specialized livestock production, whereas the non-transformed group relies more on gradual improvements and policy compensation. (3) Production transformation promotes large-scale breeding without affecting livestock mortality rates. Efficiency gains from transformation are significant only for the transformed group; forcing non-transformers to adopt transformation under current endowments may lead to efficiency losses. These findings suggest that the government should prioritize supporting herders with both the capacity and willingness to transform, address barriers faced by vulnerable groups, and emphasize productivity enhancement and moderate-scale operations to facilitate sustainable income growth. Full article

Fungal endophytes are microorganisms that inhabit plant tissues without causing disease and emerge as critical mediators of plant stress tolerance, nutrient acquisition, and ecosystem resilience under diverse climate change scenarios. Their unique position within the host allows them to modulate physiological responses more closely than external microbiota. This review explores how endophytic fungi contribute to plant adaptation under climate-induced stresses such as heat, salinity, drought, pollution, and nutrient limitation, with a focus on molecular crosstalk, functional trait modules, and metabolic trade-offs. Key findings emphasize multilayered signaling systems, including MAMP/DAMP recognition, phytohormone regulation, immune tuning, ROS dynamics, and effector deployment, while emerging mechanisms such as cross-kingdom RNA and extracellular vesicle (EV)-mediated exchange are discussed as promising but currently limited in empirical validation within many endophytic systems. Endophytes also enhance nutrient exchange through conditional carbon-for-benefit trade and may shape rhizosphere microbiota and soil activities through plant-mediated inputs. Integrative multi-omics approaches provide predominantly correlational insights into the mechanistic basis of these effects, linking molecular function to ecosystem and community outcomes. These insights have potential applications in climate-resilient agriculture, phytoremediation, and ecosystem restoration; however, their large-scale implementation requires further field-based validation and context-specific assessment. Future priorities should focus on trait-based selection, ecological modeling, and biosafety evaluation to translate microbial functions into reliable field-level strategies that support sustainable crop performance under accelerating environmental stress. Full article