Search Results (9,787)

This study investigates the characteristics and causes of a low-level wind shear (LLWS) event induced by downward momentum transport at Xining Airport, China on 5 April 2023. By utilizing Doppler Wind Lidar (DWL), Automated Weather Observing System (AWOS), and ERA5 reanalysis data, the detailed structure and synoptic-scale mechanisms of the event were analyzed. The LLWS manifested as a non-convective, meso-γ scale (2–20 km) directional wind shear, characterized by horizontal variations in wind direction. The system moved from northwest to southeast and persisted for approximately three hours. The shear zone was characterized by westerly flow to the west and easterly flow to the east, with their convergence triggering upward motion. The Range Height Indicator (RHI) and Doppler Beam Swinging (DBS) modes of the DWL clearly revealed the features of westerly downward momentum transport. Diagnostic analysis of the synoptic-scale environment reveals that a developing 300-hPa trough steered the merging of the subtropical and polar front jets. This interaction provided a robust source of momentum. The secondary circulation excited in the jet entrance region promoted active vertical motion, facilitating the exchange of momentum and energy between levels. Simultaneously, the development of the upper-level trough led to the intrusion of high potential vorticity (PV) air from the upper levels (100–300 hPa) into the middle troposphere (approximately 500 hPa), which effectively transported high-momentum air downward and dynamically induced convergence in the low-level wind field. Furthermore, the establishment of a deep dry-adiabatic mixed layer in the afternoon provided a favorable thermodynamic environment for momentum transport. These factors collectively led to the occurrence of the LLWS. This study will further deepen the understanding of the formation mechanism of momentum-driven LLWS at plateau airports, and provide a scientific basis for improving the forecasting and warning of such hazardous aviation weather events. Full article

Fungal diversity has been well explored worldwide, but such knowledge in special environments remains limited. Here, we focus on the soil from Ngari Prefecture with high altitude in the northwestern part of Xizang, China. Among the 514 fungal strains isolated from the soil samples, two strains are newly described as Cymostachys pangongensis and Emericellopsis rutogensis in the Hypocreales on the basis of both morphological and phylogenetic evidence. Cymostachys pangongensis exhibits typical characteristics of Cymostachys, viz., irregularly cymosely branched conidiophores and olivaceous brown to dark brown, fabiform conidia. It represents the sixth known species of Cymostachys and the first species isolated from soils in this genus. Emericellopsis rutogensis has typical chlamydospores and conidia of Emericellopsis, although its sexual ascomata and ascospores were not observed. Notably, these two new species belong to interesting fungal genera, whose members are well known for rich medicinal natural products. In summary, this study enriches the knowledge of fungal diversity in special environments, and the isolated strains may provide important bioresources for future applications. Full article

To enhance desalination efficiency and reduce experimental costs, the development of advanced mathematical models for EMS is essential. In this study, we propose a novel hybrid approach that integrates neural networks with high-accuracy numerical simulations of electroconvection. Based on dimensionless similarity criteria (Reynolds, Péclet numbers, etc.), we establish functional relationships between critical parameters, such as the dimensionless electroconvective vortex diameter and the plateau length of current–voltage curves. Training datasets were generated through extensive numerical experiments using our in-house developed mathematical model, while multilayer feedforward neural networks with backpropagation optimization were employed for regression tasks. The resulting AI (artificial intelligence)-driven hybrid models enable rapid prediction and optimization of EMS design and operating parameters, reducing computational and experimental costs. This research is situated at the intersection of membrane science, artificial intelligence, and computational modeling, forming part of a broader foresight agenda aimed at developing next-generation intelligent membranes and adaptive control strategies for sustainable water treatment. The methodology provides a scalable framework for integrating physically based modeling and machine learning into the design of high-performance electromembrane systems. Full article

Global environmental changes significantly alter ecosystem services (ESs), particularly in fragile regions like the Tibetan Plateau. While methodological advances have improved spatial assessment capabilities, understanding of how multiple drivers interact to shape ecosystem service heterogeneity remains limited to regional scales, especially across complex alpine landscapes. This study aims to clarify whether multi-factor interactions produce nonlinear enhancements in ES explanatory power and how these driver–response relationships vary across heterogeneous terrains. We quantified spatiotemporal patterns of four key ecosystem services—water yield (WY), soil conservation (SC), carbon sequestration (CS), and habitat quality (HQ)—across the southeastern Tibetan Plateau from 2000 to 2020 using multi-source remote sensing data and spatial econometric modeling. Our analysis reveals that SC increased by 0.43 t·hm⁻²·yr⁻¹, CS rose by 1.67 g·m⁻²·yr⁻¹, and HQ improved by 0.09 over this period, while WY decreased by 3.70 mm·yr⁻¹. ES variations are predominantly shaped by potent synergies, where interactive explanatory power consistently surpasses individual drivers. Hydrothermal coupling (precipitation ∩ potential evapotranspiration) reached 0.52 for WY and SC, while climate–vegetation synergy (precipitation ∩ normalized difference vegetation index) achieved 0.76 for CS. Such climate–restoration synergies now fundamentally shape the region’s ESs. Geographically weighted regression (GWR) further revealed distinct spatial dependencies, with southeastern regions experiencing strong negative effects of land use type and elevation on WY, while northwestern areas showed a positive elevation associated with WY but negative effects on SC and HQ. These findings highlight the critical importance of accounting for spatial non-stationarity in driver–ecosystem service relationships when designing conservation strategies for vulnerable alpine ecosystems. Full article

Over the past several centuries, many lakes in the Yunnan Plateau disappeared or are disappearing due to climate change and human activities; the developments of these lakes are thus crucial for understanding their evolutions and underlying causes. Here we present a near 260-year history of water area changes in Lake Zhehai, a disappearing lake in northeastern Yunnan of Southwest China, based on historical documents such as local and regional annals and gazetteers, water conservancy records, and old maps using GIS and remote sensing techniques, to identify the dominant drivers of the lake disappearing. Results show that the reconstructed water area of Lake Zhehai was ca. 1500, 710, 370, 340, and 110 ha in 1761, 1912, 1935, 1950, and 1975 AD; this indicates that Lake Zhehai experienced three-phase lake evolution over the past 260 years, i.e., large lake in 1761–1920 AD, shrinking lake in 1921–1980 AD, and disappearing lake since 1981. Significant changes in the water area of Lake Zhehai were mainly attributed to both climate change and human activities, especially human activities as dominant drivers during the last two phases of lake evolution. Our findings provide a reference for both understanding the driving mechanisms of large shallow lake evolution during historical times in Yunnan, as well as assessing strategies of lake environmental protection under global warming and increasing human activities. Full article

To evaluate the optimal substitution ratio of organic fertilizer for chemical nitrogen fertilizer and its underlying mechanisms, a pot experiment was conducted in the rhizosphere soil of oat (Avena sativa) on the Qinghai–Tibet Plateau. Five treatments were established: CK (control), T1 (chemical fertilizer alone), T2 (100% organic fertilizer substitution for chemical nitrogen fertilizer), T3 (30% organic fertilizer substitution for chemical nitrogen fertilizer), and T4 (60% organic fertilizer substitution for chemical nitrogen fertilizer). We analyzed soil carbon fractions, microbial community structure, carbon-cycling enzyme activities, and yield responses and applied partial least squares–structural equation modeling (PLS-SEM) to identify key regulatory pathways. The results showed that 30% organic substitution (T3) was associated with optimized soil carbon pools, improved microbial community composition, and enhanced carbon-cycling enzyme activities, while reducing the abundance of potentially harmful fungi. Structural equation modeling indicated that β-glucosidase activity and the relative abundance of Proteobacteria were the primary drivers of yield, together explaining 76% of its variation. The ecosystem multifunctionality index (EMF) was significantly and positively correlated with yield. In summary, under the conditions of this experiment, 30% organic fertilizer substitution achieved a favorable balance between soil ecological functions and crop yield, providing a valuable reference for sustainable nutrient management in oat production in high-altitude cold regions. Full article

Background/Objectives: Mitochondrial dysfunction is a major cause of brain injury in patients with primary mitochondrial disease. New mitochondrial therapeutics and non-invasive tools for efficacy monitoring are urgently needed. To these ends, succinate prodrug NV354 (methyl 3-[(2-acetylaminoethylthio)carbonyl]propionate) and diffuse optical techniques are promising. In this proof-of-concept study, we characterize NV354’s effects on microdialysis metrics of cerebral metabolism in a swine model of mitochondrial dysfunction and assess the associations of diffuse optical metrics with mitochondrial dysfunction and metabolic improvement. Methods: One-month-old swine received a four-hour co-infusion of rotenone with either the succinate prodrug NV354 (n = 5) or placebo (n = 5). Rotenone is a mitochondrial complex I inhibitor. Before and during co-infusion, cerebral metabolism was probed with microdialysis and diffuse optics. Microdialysis acquired interstitial lactate and pyruvate levels invasively, while diffuse optics measured changes in oxygen extraction fraction (OEF) and oxidized cytochrome-c-oxidase concentration (oxCCO). Results: Interstitial lactate continually increased in the placebo group (p < 0.01), but lactate levels plateaued in the NV354 group (p = 0.90). oxCCO also increased in the placebo group (p = 0.05), but OEF remained constant (p = 0.80). In the NV354 group, oxCCO increased (p < 0.01) while OEF decreased (p < 0.01). Conclusions: Microdialysis results suggest that NV354 treatment can increase oxygen metabolism in large animals with mitochondrial dysfunction. The optical oxCCO metric was also sensitive to metabolic changes induced by rotenone and NV354 administration. Full article

Background and Clinical Significance: Breast hemangioma is an extremely rare benign vascular tumor of the breast. Its imaging findings are nonspecific, and differentiation from malignant tumors such as encapsulated papillary carcinoma, mucinous carcinoma or angiosarcoma is often difficult. We report a case of breast hemangioma that showed slow growth over an 11-year period. Case Presentation: A woman in her 50s presented with a well-defined 11 mm mass in the upper outer quadrant of the left breast detected by ultrasonography. A core needle biopsy revealed a benign lesion, and follow-up was recommended. Eleven years later, the mass had increased to 27 mm. Magnetic resonance imaging showed high signal intensity on T2-weighted images and a fast-plateau enhancement pattern extending from the periphery to the center. Although malignancy was suspected, vacuum-assisted biopsy revealed a hemangioma. Conclusions: Breast hemangioma can show slow enlargement over a long period. Recognition of a characteristic peripheral-to-central enhancement pattern may aid in distinguishing this benign vascular lesion from malignant tumors. Full article

Vegetation restoration is an effective strategy to improve the ecosystem function of the Loess Plateau. Soil microbiomes play a critical role in maintaining soil multifunctionality (SMF). However, the role of aggregate-scale microbial communities and interactions in regulating SMF during vegetation restoration remains poorly understood. Here, we selected six types of vegetation restoration measures in the Loess Plateau, including natural grassland (NL), Medicago sativa (MS), Hippophae rhamnoides (HR), Caragana korshinskii (CK), Armeniaca vulgaris (AV), and Populus alba (PA), and used abandoned land (AL) as a control to identify key microbial mechanisms driving SMF at the aggregate scale. The results show that vegetation restoration increased bacterial diversity, fungal network complexity, and SMF, especially in AV. In contrast, fungal diversity and bacterial network complexity exhibited asynchronous dynamics across different-sized aggregates. Soil microbial diversity peaked at micro-aggregates (0.053–0.25 mm), while fungal network complexity increased with decreasing aggregate size. The structural equation model confirmed that fungal community composition in large macro-aggregates (>2 mm) and fungal network complexity in <2 mm aggregates were the key drivers of SMF. Our results emphasize the divergent mechanisms by which microbial properties influence SMF across aggregate sizes, highlighting the importance of fungal communities in maintaining soil ecosystem functions. Full article

Magnesium phosphate cement (MPC) holds great potential for rapid repairs, yet its practical application is limited by its intense hydration exotherm. While many existing studies confirm paraffin (PA)’s ability to regulate hydration heat in other cement-based materials, the comparison of hydration heat regulation efficacy among PAs with different phase change temperatures and the accompanying performance trade-offs in MPC systems remain insufficiently explored. This study comprehensively evaluates the effects of three PAs with distinct phase change characteristics (n-C18, n-C20, n-C22) and their contents on the hydration heat regulation and performance of MPC. Direct incorporation of PAs was adopted to assess its practical feasibility, considering construction cost-effectiveness. Investigations were conducted using hydration heat release tests, temperature rise monitoring, DSC, mechanical tests, XRD, and SEM. Results show that all PAs significantly retarded heat release and suppressed temperature rise, with efficacy increasing with phase change temperature; a maximum exothermic peak reduction of 64% was achieved with 4% n-C22. PAs also introduced distinct temperature plateaus near their phase change temperature, further enhancing temperature regulation. As a key trade-off, compressive strength decreased with increasing PA content, but mixtures with n-C18 ≤ 8%, n-C22 ≤ 4%, and n-C20 = 2% still met the standard strength requirement for rapid repair, 3 h compressive strength ≥ 20 MPa. Microstructural analysis reveals that while regulating hydration heat, PA also hindered the hydration product formation and crystallization, underpinning the observed performance trade-offs. This study establishes a clear performance correlation between PAs with different phase change temperatures and MPC, clarifies the intrinsic trade-offs between heat regulation and mechanical properties, and offers actionable guidance for engineering applications—facilitating the development of high-performance PA/MPC composites with controllable heat release for rapid repair scenarios. Full article

Understanding residents’ perceptions of ecosystem services (ES) and ecosystem disservices (EDS) is crucial for protected areas governance. This study, conducted in China’s Three-River-Source National Park (TNP), employed participatory rural appraisal and household questionnaires to examine local cognitive patterns of ES and EDS, along with their socio-spatial heterogeneity and perceived synergies and trade-offs among them. The key findings are as follows: (1) Cultural services received the highest scores, followed by regulating services, whereas provisioning services, especially food provisioning, were rated as relatively inadequate. Safety threats were considered the most severe EDS. Overall, a Matthew Effect emerged: services with high current perception scores showed an improving trend, while those with low scores deteriorated. (2) Spatially, ES/EDS evaluation scores exhibited a “core zone < general control zone < peripheral zone” gradient. Socio-demographic and economic factors also influenced residents’ perceptions; women and the elderly were especially more concerned about food and energy supply shortages and safety issues. (3) The relationships among the various ES and EDS are primarily synergistic rather than trade-offs. Specifically, gains in regulating services were associated with enhanced cultural services, while declines in provisioning services and intensified safety threats coincided with the deterioration of material EDS. These findings offer a scientific basis for managing protected areas in high-altitude, ecologically fragile regions and provide practical insights for balancing ecological conservation with community development. Full article

Fractional Vegetation Cover (FVC) dynamics on the Qinghai–Tibetan Plateau (QTP) are critical indicators for assessing ecosystem condition. However, uncertainties persist in the accuracy of existing FVC products over the QTP due to retrieval differences, scale effects, and limited validation data. This study utilized the Google Earth Engine platform to integrate unmanned aerial vehicle (UAV) observations, Sentinel-2, MODIS, climate, and topography datasets, and proposed a comprehensive framework incorporating dual-index screening, machine learning optimization, and multidimensional validation to systematically assess the accuracy of GEOV3, GLASS, and MuSyQ FVC products in the alpine grasslands. The dual-index screening reduced validation uncertainty by improving the spatial representativeness of ground data. To build a high-precision evaluation dataset with limited inter-class coverage, recursive feature elimination and grid search were applied to optimize five ML models, and CatBoost achieved the superior performance (R² = 0.880, RMSE = 0.122), followed by XGBoost, GBM, LightGBM, and RF models. Four validation scenarios were implemented, including direct validation using 250 m UAV plot FVC and multi-scale validation using a 10 m FVC reference aggregated to product grids. Results show that GEOV3 (R² = 0.909–0.925, RMSE = 0.082–0.103) outperformed GLASS (R² = 0.742–0.771, RMSE = 0.138–0.175) and MuSyQ (R² = 0.739–0.746, RMSE = 0.138–0.181), both of which exhibited systematic underestimation. This framework significantly enhances FVC product validation reliability, providing a robust solution for remote sensing product validation in alpine grassland ecosystems. Full article

Objectives: To characterize the learning curve of endoscopic transsphenoidal pituitary adenoma surgery performed by a single neurosurgeon, assess how operative time, resection rates, and clinical outcomes evolved with experience, and identify tumor-related factors influencing surgical performance. Methods: This retrospective study included 123 consecutive endoscopic transsphenoidal pituitary adenoma resections performed between 2018 and 2025. Cases were divided into quartiles according to chronological order. Clinical, radiological, endocrinological, and operative variables were analyzed. Gross total resection (GTR), biochemical remission, postoperative complications, and visual and cranial nerve outcomes were compared between quartiles. A segmented linear regression model was applied to identify changepoints in the operative-time learning curve. Statistical significance was set at p < 0.05. Results: The mean operative time decreased by 31.8%, from 160.8 min in Quartile 1 to 109.7 min in Quartile 4. Segmented regression revealed two changepoints at cases 47 and 85, defining three learning phases: a steep improvement phase, a consolidation phase, and a plateau. GTR was achieved in 51.2% of patients and did not significantly differ across quartiles. For Knosp 0–2 tumors, GTR was 76.1% overall; for Knosp 3–4 tumors, 30%. Tumor diameter, Knosp grade, and sphenoid sinus invasion were strongly associated with lower GTR rates (all p < 0.05). Biochemical remission was achieved in 74.2% of patients with functional adenomas. New or worsened postoperative pituitary insufficiency significantly decreased across quartiles (p < 0.001). Rates of postoperative diabetes insipidus (30.8%) and CSF leak (6.5%) were comparable with published literature and showed no consistent temporal trend. Conclusions: A clear learning curve exists in endoscopic pituitary surgery, with operative proficiency achieved after approximately 50 cases and an experienced plateau after ~90 cases. Surgical experience significantly reduced operative time and postoperative pituitary insufficiency but did not influence GTR rates, likely due to a high and increasing proportion of large tumors with cavernous sinus invasion. Tumor size, Knosp grade, and sphenoid sinus invasion were identified as major determinants of surgical complexity and should be accounted for when evaluating learning curves and surgical outcomes. Full article

Understanding the genetic basis of agronomic traits in quinoa adapted to the Qinghai–Tibet Plateau is essential for developing high-yield cultivars, as conventional breeding is constrained by limited molecular tools. In this study, 300 cultivated accessions were evaluated for five quantitative traits, and whole-genome resequencing generated 3.69 million high-quality SNPs. Population structure analysis and genome-wide association study (GWAS) were conducted, with integration of seed developmental transcriptomes to refine trait-associated loci. A highly admixed genetic background (K = 7) was revealed, and 11 significant QTLs across seven chromosomes were identified, involving genes related to metabolism, transport, and cell-wall formation. Among these, CesA4 (CQ042210) showed a strong association with thousand grain weight (TGW) and a distinct expression maximum at the early seed-filling stage. These results provide a genomic framework for understanding trait variation in plateau-adapted quinoa and highlight promising targets for marker-assisted breeding. Full article

This paper presents a compact and accurate readout circuit for remote two-wire resistive sensors, based on an inverting operational amplifier with a fixed bias voltage, diode steering, and unidirectional square-wave excitation generated by a microcontroller. The proposed method determines the sensor resistance by directly sampling two steady-state voltage plateaus at the op-amp output during alternating excitation phases. This approach enables fast, lead-wire-insensitive measurements without the need for analog filtering or precise PWM duty-cycle control. The architecture supports sensor array multiplexing via analog switches, allowing scalable, low-power implementation. Experimental results demonstrate a maximum relative error of 0.23% across a wide resistance range (0.5–3.5 kΩ), confirming the method’s suitability for low-cost, embedded, and remote sensing applications. Full article