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Water constraints disturb and damage the growth and development of grassland vegetation mainly through both atmospheric and soil pathways. In the background of rapid climate change in the future, the impacts of water constraints on grasslands are expected to further deepen. However, current studies lack reports exploring the frequency, intensity, and area of land-atmospheric compound drought on carbon indicators in grassland ecosystems. In this study, we analyze the response of China grasslands to dual terrestrial-atmospheric water constraint events using ISIMIP gross primary productivity (GPP) data to reveal the carbon cycle-climate feedback relationships over the Chinese grassland. We found that the occurrence probability of compound drought events (i.e. land-atmospheric water constraint) was 3–4 times higher than that of random drought events, and the frequency, intensity, and affected area of compound droughts were significantly higher than that of single droughts. Compound droughts caused a decline of up to 20.27% in GPP of grassland ecosystems in China, while the decline of single atmospheric drought or soil drought was only 12.34% and 14.32%. Which is because vapor pressure deficit and soil moisture are a set of strongly coupled bivariate variables, and the continued strengthening of the land-atmospheric feedback causes a higher probability of occurrence of compound drought events and an increased impact on ecosystem GPP.

The acquisition of 2–50 Hz low-frequency vibration signals is of great significance for the monitoring researches on engineering seismology, bridges & dams, oil & gas exploration, etc. A multi-cantilever beam low-frequency FBG acceleration sensor is proposed against the low sensitivity that predominates in the low-frequency vibration measurement by FBG acceleration sensors. Structural parameters of the sensor is subjected to simulation analysis and optimization design using the ANSYS software; the real sensor is developed based on the simulation results in the following manner: Three rectangular of the cantilever beams are evenly arranged around the mass block at 120°to improve the sensitivity and alleviate the transverse crosstalk of sensor; in the end, a performance test is performed on the sensor. According to the research findings, the sensor, whose natural frequency is approximately 64 Hz, is applicable for monitoring the low-frequency vibration signals within the range 16–54 Hz. The sensor sensitivity is approximately 87.955 pm/m s - 2 , the linearity being greater than 99%, the transverse interference immunity being lower than 2.58%, and the dynamic range being up to 86 dB. The findings offer a reference for developing sensor of the same type and further improving the sensitivity of fiber optic acceleration sensor.

In drought studies, a standardized index has better applicability, and a distributed index can improve our ability to identify the spatial aspects of droughts. However, for socioeconomic drought, none of the existing indices is both spatially distributed and standardized. To fill this gap, this study proposes a novel index, Distributed Standardized SocioEconomic Drought Index (DSSEDI), to accurately identify socioeconomic drought over time and space. Moreover, a high-precision, long-term gridded water demand dataset is developed as the basis of establishing this index. For the East River basin, DSSEDI accurately detected significant socioeconomic droughts in 2002, 2004–2005, 2009, and 2011, mostly during autumn-winter-spring. The Pearl River Delta was found to have significant population and economic vulnerability to droughts, with economic exposure peaking at $4.66 billion near Shenzhen during severe events. As a standardized index, it can be adaptable to other regions. Overall, this study provides a new perspective on socioeconomic drought by increasing spatial resolution of water demand data and accounting for the impacts of water conservation measures on observations during the establishment process of DSSEDI.

Rockburst physical model test, as one of the important means to study deep tunnel engineering, reflects the main influencing factors of rockburst into the model test through similar theory, so as to reveal the formation mechanism, influencing factors and evolution law of different types of rockburst in deep tunnels. In order to study the mechanical properties of white sandstone in deeply buried tunnels at high ground temperatures, materials suitable for conducting rockburst physical and mechanical tests were developed on the basis of the Daqian Shi Ling tunnel project, and similar material ratios were preferentially selected on the basis of white sandstone. Judged by the rock burst propensity, similar materials with low strength and high brittle characteristics, can better simulate the characteristics of white sandstone, and all show a strong propensity to rock burst, is the ideal rock burst similar materials. Uniaxial compressive tests were conducted on similar materials and the original rock at different temperatures, and comparative analysis was performed. Through the study of stress, displacement and modulus of elasticity, it was concluded that the compressive strength of similar materials gradually increased with temperature in the range of 20–100°C, and the vertical displacement at peak strength decreased with increasing temperature. The damage forms of white sandstone and similar materials at different temperatures were comparatively analyzed, and it was obtained that the damage forms of white sandstone and similar materials were basically the same, with a few specimens showing tensile and shear damage, and most specimens showing the form of combined tensile and shear damage. The study of rock burst similar materials and the development of the failure characteristics of rock burst under the action of thermal coupling are of great significance to the mechanism of rock burst generation and prediction.

The genus Acer pseudosieboldianum , a cold-tolerant maple species native to northeastern China, exhibits remarkable adaptability to extreme winters and vibrant autumn foliage, yet the molecular mechanisms underlying these traits remain poorly characterized. Here, we conducted the first genome-wide identification and functional analysis of the R2R3-MYB transcription factor family in A. pseudosieboldianum to elucidate its roles in cold stress response and anthocyanin biosynthesis. Using a combination of bioinformatic approaches and transcriptomic profiling, we identified 95 ApseMYB genes, classified into 12 subfamilies with conserved motif architectures and structural features. Cis-regulatory element analysis identified 34 genes enriched in low-temperature response motifs, while transcriptomic and qPCR validation highlighted 22 cold-responsive and 14 leaf color-associated ApseMYB genes, including ApseMYB31 (28-fold induction at 4 °C) and ApseMYB16 (52-fold upregulation during leaf reddening). Subcellular localization analysis indicated that ApseMYB31 and ApseMYB16 predominantly localize to the nucleus, consistent with the canonical nuclear activity of R2R3-MYB transcription factors. This study revealed that members of the R2R3-MYB gene family in A. pseudosieboldianum play pivotal roles in mediating both low temperature resistance and leaf anthocyanin accumulation, providing new insights for molecular breeding of cold-tolerant ornamental trees.

Persistent droughts pose a threat to agricultural production, and the changing environment worsens the risk of drought exposure. Understanding the propagation of drought in changing environments and assessing possible impact factors can help in the early detection of drought, guiding agricultural production practices. The current study cannot reflect the propagation status of drought to the total terrestrial hydrological drought, so this work creatively investigated the atmospheric to hydrological drought propagation time in the Yangtze River Basin under the dynamic and static perspectives based on the Standardized Precipitation Evapotranspiration Index and the Terrestrial Water Storage Anomalous Drought Index, fine-tuned the time scale to the seasonal scale, and explored the contributing capacity of the variable interactions. The results show that: (1) under the dynamic perspective, while the propagation time is decreasing in the annual scale, the spring season shows the opposite trend; and (2) large variability exists in the timing of drought propagation at spatial scales, with elevation playing the most important influential role, and bivariate interactions contributing stronger explanations compared to single variables. This study highlights the importance of considering the impact of variable interactions and contributes to our understanding of the response of secondary droughts to upper-level droughts, providing valuable insights into the propagation of droughts to total terrestrial hydrologic drought.

Water inflow analysis is critical for subsea tunnel construction. However, existing studies largely concentrate on the inflow issues pertaining to single-hole tunnels. To address current practical engineering problems, a three-hole parallel configuration is common for subsea tunnels, which may alter water inflow patterns due to the influence of their seepage fields. Herein, numerical simulations are conducted to investigate the water inflow characteristics of a three-hole parallel subsea tunnel. Specifically, the impact of various factors on the water inflow phenomenon, including the permeability coefficient of the surrounding rock, the depth of the seawater, the depth of the tunnel, the spacing between tunnels, and the relative size of the tunnels, are comprehensively studied. Furthermore, based on the principles of the analytic hierarchy process and fuzzy mathematics, an exhaustive assessment framework is developed to evaluate the water inflow of three-hole parallel subsea tunnels. The results indicate that there is a mutual influence between the three parallel tunnels, differing from the predicted water inflow, which is overestimated in a single-hole tunnel model. Therefore, the water inflow assessment for a three-hole parallel subsea tunnel system should account for the inter-tunnel influences. The findings of this study offer valuable insights for the design of waterproofing and drainage systems in three-hole subsea tunnels.

Shaft structures in high-rise buildings may increase fire coverage due to chimney effects. However, few previous studies have considered the motion of the flue gas under the combined effect of the chimney effect and thermal buoyancy. So, we set a continuous gradient differential pressure opening based on the characteristics of the chimney effect in winter. The CFD method is used to simulate 12 operating conditions with different fire source locations and rates of heat release from the ignition source. We compare and analyze the temperature rise, the flue gas rise law and the variation of the thermal pressure difference between the inner and outer shafts for different fire source powers. The results show that, in the case of low-floor fires, the range of temperature appreciation and fluctuation at the local measurement point increases with the fire power and the distribution of temperature appreciation decreases with the height. The relationship between the dimensionless time and the dimensionless height of the flue gas layer is exponential for different fire position conditions. The fire causes the neutral surface to shift, and below the original neutral surface, the higher the position of the fire source, the more pronounced the shift of the neutral surface.

The red color formation of Acer mandshuricum leaves is caused by the accumulation of anthocyanins primarily, but the molecular mechanism researches which underlie anthocyanin biosynthesis in A. mandshuricum were still lacking. Therefore, we combined the transcriptome and metabolome and analyzed the regulatory mechanism and accumulation pattern of anthocyanins in three different leaf color states. In our results, 26 anthocyanins were identified. Notably, the metabolite cyanidin 3-O-glucoside was found that significantly correlated with the color formation, was the predominant metabolite in anthocyanin biosynthesis of A. mandshuricum . By the way, two key structural genes ANS ( Cluster-20561.86285 ) and BZ1 ( Cluster-20561.99238 ) in anthocyanidin biosynthesis pathway were significantly up-regulated in RL, suggesting that they might enhance accumulation of cyanidin 3-O-glucoside which is their downstream metabolite, and contributed the red formation of A. mandshuricum leaves. Additionally, most TFs (e.g., MYBs, bZIPs and bHLHs) were detected differentially expressed in three leaf color stages that could participate in anthocyanin accumulation. This study sheds light on the anthocyanin molecular regulation of anthocyanidin biosynthesis and accumulation underlying the different leaf color change periods in A. mandshuricum , and it could provide basic theory and new insight for the leaf color related genetic improvement of A. mandshuricum .

The high-precision prediction of near-space atmospheric temperature holds significant importance for aerospace, national defense security, and climate change research. To address the deficiencies of extracting features in conventional convolutional neural networks, this paper designs a ConvLSTM hybrid model that combines the spatiotemporal feature extraction capability of 3D convolution with a residual attention mechanism, effectively capturing the dynamic evolution patterns of the near-space temperature field. The comparative analysis with various models, including GRU, shows that the proposed model demonstrates superior performance, achieving an RMSE of 2.433 K, a correlation coefficient R of 0.993, and an MRE of 0.76% on the test set. Seasonal error analysis reveals that the prediction stability is better in winter than in summer, with errors in the mesosphere primarily stemming from the complexity of atmospheric processes and limitations in data resolution. Compared to traditional CNNs and single time-series models, the proposed method significantly enhances prediction accuracy, providing a new technical approach for near-space environmental modeling.