Search Results (66)

The carbon metabolism activity of rhizosphere soil microbial communities is an essential indicator for assessing soil ecosystem health, as it directly affects soil nutrient cycling and the stability of organic matter. However, there is a limited understanding of the carbon metabolism characteristics of rhizosphere soil microorganisms in alfalfa (Medicago sativa L.) of different ages and their relationships with soil physicochemical properties. This study used Biolog EcoPlates to evaluate the carbon metabolism activity, functional diversity, and carbon-source utilization preferences of rhizosphere soil microbial communities in 5-, 7-, and 9-year-old alfalfa grasslands on the semi-arid Loess Plateau of western China. We analyzed the relationships between soil physicochemical properties and microbial carbon metabolism characteristics, considering their potential covariation. The results showed that, with the extension of alfalfa planting years, the rhizosphere soil water content decreased significantly, pH decreased slightly, but soil organic carbon, total nitrogen, and total phosphorus contents increased significantly. The rhizosphere soil microbial community of 9-year-old alfalfa exhibited the highest carbon metabolism activity, Shannon diversity index, and carbon-source utilization. Rhizosphere soil microorganisms from different-aged alfalfa showed significantly different preferences for carbon-source utilization, with microorganisms from 9-year-old alfalfa preferentially utilizing carbon sources such as N-acetyl-D-glucosamine, D-mannitol, and D-cellobiose. Redundancy analysis revealed that soil water content was among the most important factors influencing the carbon metabolism activity of rhizosphere soil microbial communities while acknowledging that the relative contributions of soil water content, organic carbon, and nitrogen require careful interpretation, owing to their potential collinearity. This study demonstrates that, under rain-fed conditions in the semi-arid Loess Plateau, the continuous cultivation of alfalfa for nine years led to a significant decrease in soil water content but enhanced the rhizosphere soil nutrient status and microbial carbon metabolism activity, with no apparent signs of microbial functional degradation, although soil water depletion was observed. These findings highlight the complex interactions among multiple soil factors in influencing microbial carbon metabolism, providing valuable microbiological insights for understanding the sustainability of alfalfa grasslands and a theoretical basis for the scientific management of alfalfa grasslands in the semi-arid Loess Plateau region. Future research should consider longer planting periods to determine the critical age of alfalfa grassland degradation under semi-arid conditions and its associated microbial mechanisms. Full article

Soybean [Glycine max (L.) Merr.] is a globally significant crop that provides essential meal protein and vegetable oil for human consumption. The protein content in soybean seeds is a critical factor that affects nutrition regarding human dietary needs as well as livestock feed. Therefore, identifying the key genes that affect the soybean seed protein content is one of the major goals in soybean research. To identify candidate genes and related pathways involved in soybean seed storage protein during seed development, an RNA-seq analysis was conducted in two soybean varieties that differ in protein content. A series of pathways related to seed protein metabolism, including “Photosynthesis”, “TCA cycle”, and “Starch and sucrose metabolism” pathways, were identified through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Seven candidate genes exhibiting two different gene regulation patterns were identified, six of which are directly related to the seed storage protein pathway, and one of which is related to the carbon binding pathway. An integrated analysis of transcriptomic and candidate gene expression trend suggested that 40 days after flowering (DAF) might be a crucial period for seed protein accumulation in soybean. Through a Weighted Gene Co-expression Network Analysis (WGCNA), two modules and two novel hub genes were found, which may be highly correlated with seed protein development. These findings might be valuable for a complete understanding of the genetic basis of seed protein content and lay a theoretical foundation for future gene functional identification and breeding efforts in soybean. Full article

The application of rebar reinforced ultra-high-performance concrete (R-UHPC) has been increasingly adopted in engineering structures due to its exceptional mechanical performance and durability characteristics. Nevertheless, when subjected to combined saline and stray current conditions, R-UHPC remains vulnerable to severe corrosion degradation. This investigation examined the corrosion performance and tensile behavior evolution of R-UHPC containing 2.0 vol% copper-coated steel fiber content and HRB400 steel rebar with a reinforcement ratio of 3.1%. The accelerated corrosion process was induced through an impressed current method, followed by direct tensile tests at varying exposure periods. The findings revealed that the embedding of rebar in UHPC led to the formation of fiber-to-rebar (F-R) conductive pathways, generating radial cracks besides laminar cracks. The bonding between rebar and UHPC degraded as corrosion progressed, leading to the loss of characteristic multiple-cracking behavior of R-UHPC in tension. Meanwhile, R-UHPC load-bearing capacity, transitioning from gradual to accelerated deterioration phases with prolonged corrosion, aligns with steel fibers temporally. During the initial 4 days of corrosion, the specimens displayed surface-level corrosion features with negligible steel fiber loss, showing less than 4.0% reduction in ultimate bearing capacity. At 8 days of corrosion, the steel fiber decreased by 22.6%, accompanied by an 18.3% reduction in bearing capacity. By 16 days of corrosion, the steel fiber loss reached 41.5%, with a corresponding bearing capacity reduction of 29.1%. During the corrosion process, corrosion cracks and load-bearing degradation in R-UHPC could be indicated by the ultrasonic damage factor. Full article

This study investigates the causal impact of stock price crash risk on the cost of equity (COE) in China’s segmented A- and B-share markets with an emphasis on ownership structures and market regimes. Employing a bootstrap panel Granger causality framework, Markov-switching dynamic regression, and panel threshold regression models, the analysis reveals that heightened crash risk significantly increases COE, with the effects being more pronounced for A-shares because of domestic investors’ heightened risk sensitivity. This relationship further intensifies in bull markets, where investor optimism amplifies downside risk perceptions. Ownership segmentation plays a critical role, as foreign investors in B-shares exhibit weaker reliance on firm-level valuation metrics, favoring broader risk-diversification strategies. These findings offer actionable insights into corporate risk management, investor decision making, and policy formulation in segmented and emerging equity markets. Full article

The impact of urbanization on the spatial distribution of extreme precipitation has become a major topic in the field of urban hydrology. This study used an urban canopy model (UCM) coupled with a Weather Research and Forecasting model (WRF) to analyze two extreme precipitation events experienced by the Pearl River Delta on 12–13 June (monsoon rainstorm) and 16–17 September (typhoon rainstorm) in 2018. The results showed that both experiments, considering UCM and not considering UCM, can effectively simulate the spatial distribution of two precipitation events in Pearl River Delta urban agglomeration. The root mean square errors of simulation and observation data of the two precipitation events by the UCM scheme were 14.6 mm and 16.7 mm, respectively, indicating relatively high simulation accuracy. The simulated precipitation amounts for the two rainfall events were increased by 2.3 mm and 3.0 mm, respectively. The simulation results of the two precipitation events showed that compared to agricultural land, urban and built-up land have experienced temperature increases of approximately 0.7 °C and 1 °C, respectively. The air-specific humidity of the two precipitation events increased by approximately 0.5 g/kg and 1.2 g/kg, respectively. These differences between UCM and NON simulations confirm that the increase in near-surface air humidity and temperature significantly enhances the intensity of extreme precipitation in the Pearl River Delta urban agglomeration. Full article

Ovarian tissue is critical for goose reproduction. This study aimed to investigate gene regulation by DNA methylation in relation to the reproductive traits of geese. We performed whole-genome bisulfite sequencing (WGBS) on ovarian tissues from Sichuan white geese (high-laying-rate group: HLRG, ♀ = 3; low-laying-rate group: LLRG, ♀ = 3) during the laying period. The results showed a higher level of hypermethylated differentially methylated regions (DMRs) in the HLRG, indicating a higher overall methylation level compared to the LLRG. In total, we identified 2831 DMRs and 733 differentially methylated genes (DMGs), including 363 genes with upregulated methylation. These DMGs were significantly enriched in pathways related to microtubule function (GO:0005874; GO:0000226), GnRH secretion, thyroid hormone signaling, ECM-receptor interaction, and PI3K–Akt signaling. Integration with RNA-seq data identified eight overlapping genes between DMGs and differentially expressed genes (DEGs), with five genes (CUL9, MEGF6, EML6, SYNE2, AK1BA) exhibiting a correlation between hypomethylation and high expression. EML6, in particular, emerged as a promising candidate, potentially regulating follicle growth and development in Sichuan white geese. Future studies should focus on further verifying the role of the EML6 gene. In conclusion, this study provides important insights into the regulatory mechanisms of DNA methylation influencing reproductive traits in geese, offering novel candidate markers for future goose breeding programs. Full article

To explore the impact of epigenetic modifications on egg-laying traits in geese, we employed genome-wide bisulfite sequencing (WGBS) to analyze DNA methylation patterns in pituitary tissues of high-(HYP) and low-yield (LYP) Sichuan White geese. We achieved high-quality sequencing data (mean 19.09 Gb raw reads, 15.49 Gb clean reads, 79.1% unique mapping rate) with a bisulfite conversion efficiency of 99.88%. Comparative analysis revealed 2394 differentially methylated regions (DMRs) and 422 differentially methylated genes (DMGs) between HYP and LYP groups. We identified five key differentially methylated candidate genes (BMPER, INHA, NMBR, NK3R, and DSG2) linked to egg-laying traits in Sichuan White geese. Integrated GO and KEGG enrichment analysis conducted to explore the role of regulatory networks of epigenetic modification on egg-laying traits in Sichuan White geese identified multiple metabolic pathways associated with egg-laying traits (promoting egg transport, ovulation, and yolk protein synthesis and secretion), thus providing a basis for subsequent functional verification. Full article

The petrology, geochemistry, and zircon U-Pb chronology of the Huoshaodian pluton in the Liuba area of the western part of the South Qinling tectonic belt are investigated in this study. The Huoshaodian pluton consists of gabbro, quartz diorite, and granodiorite, and the dominated rock type is quartz diorite. The results indicate that the Huoshaodian pluton belongs to the calc-alkaline series. In the chondrite-normalized REE, all of the samples showed similar patterns, with an enrichment of light REEs and depletion of heavy REEs, but they showed slight differences in the degrees of Eu anomalies. The primitive mantle-normalized trace element diagram reveals an enrichment of large-ion lithophile elements (LILEs) and light rare earth elements (LREEs), as well as depleted high field strength elements (HFSEs). The zircon U-Pb dating results reveal that the gabbro, quartz diorite, and granodiorite have crystallization ages of 214.9 ± 0.58 Ma, 215.0 ± 1.2 Ma, and 215.4 ± 1.9 Ma, respectively, indicating that the Huoshaodian pluton was emplaced during the late Triassic period (214.9–215.4 Ma). In terms of petrogenesis, the gabbro of the Huoshaodian pluton originates from a transitional lithospheric mantle that has undergone fluid metasomatism and partial melting. Specifically, it originated through 1%–2% garnet spinel peridotite undergoing partial melting. In addition, the gabbro underwent a slight degree of contamination by crustal materials during its ascent and intrusion, with some continental crust material being incorporated. The quartz diorite and granodiorite of the Huoshaodian pluton are formed through partial melting processes occurring within the normal lower crust. Combined with the previous studies on the early Mesozoic tectonic evolution of the South Qinling, this study proposes that the formation mechanism of the Huoshaodian pluton may be as follows: in the early Triassic, the Mianlue Ocean subducted northward beneath the Qinling microblock, resulting in a large-scale continental-continental collision between the North China Block and the Yangtze Block; when the oceanic crust subducted to a certain depth, the detachment of the subducting slab triggered the upwelling of mantle material. The heat from mantle-derived magma caused the partial melting of the mafic lower crust, while the mafic magma entered into the upper granitic magma chamber and began to mix. Due to the high viscosity contrast and temperature difference between the two end-member magmas, incomplete mixing led to the formation of a melt with distinct adakitic characteristics and a mafic melt representing mantle-derived material. Full article

The formation of early Mesozoic granitoid plutons in the Qinling Orogen is widely regarded as a result of the collision and accretion between the Yangtze Block and the South Qinling Block during the early Mesozoic, but the specific magmatic process, source composition, tectonic environment and deep dynamic background remain controversial. This study reports the petrology, zircon U–Pb geochronology, and whole-rock geochemistry of diorites from the Liuba and Qingyangyi plutons in the South Qinling, to provide new evidence for understanding the final collision tectonic evolution process of Qinling Orogenic belt. The Liuba and Qingyangyi plutons, located in the central part of the South Qinling region, are primarily composed of quartz diorite and quartz monzodiorite, respectively. The results indicate that the weighted mean crystallization ages of the quartz diorite in the Liuba pluton range from 216.1 ± 0.8 Ma to 217.1 ± 1.3 Ma, with the weighted mean crystallization ages of its MMEs being 215.4 ± 1.0 Ma. The crystallization ages of the quartz monzodiorite in the Qingyangyi pluton range from 214.6 ± 0.9 Ma to 215.4 ± 0.9 Ma, suggesting that both plutons were formed in the late Triassic. The investigated plutons are characterized as right-leaning and have weak negative Eu anomalies on the chondrite-normalized REE patterns diagram. The large ion lithophile elements (LILE) Rb, Ba, Th and K are relatively enriched, while high-field strength elements (HFSE) Nb, Ta, Ti and P are strongly depleted. The formation of numerous MMEs in the Liuba pluton is the product of magmatic mixing. The Liuba and Qingyangyi plutons are the results of crust thickening and partial melting of lower crust caused by the comprehensive late Triassic collision between the Yangtze Block and the North China Block (NCB), and are the manifestation of magmatic intrusion along the South Qinling tectonic belt in the late Triassic period. Full article

The goal of this paper is to study the behavior of non-ferrous metal futures’ volatilities in Chinese future market by applying a multifractal perspective. In particular, in order to obtain key indicators that describe the characterization of non-ferrous metal futures’ volatility behavior, we uses noise-removed EMD-MF-DFA and original MF-DFA methods to conduct a comparative analysis on the return time series of four non-ferrous metal futures, which are Aluminum future, Copper future, Zinc future and Lead future traded on the Shanghai Futures Exchange. This numerical study shows that the indicator established in characterizing the volatility of four non-ferrous metal futures is robust. In addition, we have the following four conclusions: First, there are obvious multifractal phenomena of non-ferrous metal futures in Chinese market, and it shows that Aluminum future has the largest degree of multifractality, and Copper future has the smallest degree of multifractality, which indicates that Aluminum future has the highest volatility complexity, and Copper future has the smallest volatility complexity. Second, it is found that the volatility complexity of these four non-ferrous metal futures is caused by long-range correlation. Third, this study also supports the current judgment that “Copper future has the greatest investment opportunity”. Finally, combined with analysis results, we also give suggestions to investors, producers, and regulators body for non-ferrous metal futures market in China. Full article

The green peach aphid, Myzus persicae, is a notorious pest worldwide. We collected a field population of the pest (FZQ-F) that exhibited high resistance to neonicotinoids. Exposure to neonicotinoids can induce oxidative damage in animals; however, it remains unclear whether antioxidant enzymes contribute to the innate immune response of neonicotinoid-resistant pests against high doses of insecticides. Treatment with sublethal doses of thiacloprid (LC₁₀ and LC₂₅) for 3, 6, 12, 24, 48, and 72 h resulted in significantly increased reactive oxygen species (ROS), including H₂O₂ content, in FZQ-F adults, indicating insecticide-induced oxidative stress. Additionally, the peroxidase activity in FZQ-F adults increased after thiacloprid exposure. Using comparative genomics, we identified 31 heme peroxidases in M. persicae with a typical “2Cys” structure, and phylogenetic analyses divided them into five groups. Comparative transcriptomes revealed that MpPxd2 and MpPxd4 were significantly upregulated in thiacloprid-treated aphids. Thiacloprid exposure significantly induced MpPxd2 and MpPxd4 expression levels, consistent with high H₂O₂ content and peroxidase activity. The knockdown of MpPxd2 or MpPxd4 in FZQ-F increased their susceptibility to imidacloprid, thiacloprid, and thiamethoxam, verifying the protective role of the heme peroxidases against neonicotinoids in aphids. The knockdown of MpPxd2 or MpPxd4 also led to shorter longevity and a low fecundity of adult aphids at 31 °C compared to controls. The results show that MpPxd2 or MpPxd4 is important in how cells respond to oxidative stress and may help resistant M. persicae pests to handle neonicotinoids. Full article

Neonicotinoid resistance is increasingly prevalent in the agricultural pest Myzus persicae. Lipids play a critical role in insect defense systems, but their contribution to insect neonicotinoid resistance is disregarded. We conducted metabolomics and transcriptomics studies on M. persicae thiacloprid-resistant (THG-R) and -susceptible (FFJ-S) populations. A total of 149 lipid metabolites were identified, with 90 upregulated and 59 downregulated in THG-R compared to in FFJ-S. Metabolites in the arachidonic acid (AA) pathway substantially varied between THG-R and FFJ-S. For example, arachidonic acid, (±)11-HETE, and prostaglandin B1 were significantly upregulated, while prostaglandin A1, tetranor-PGDM, 8,15-diHETE, and (±)11(12)-EET were significantly decreased in THG-R. Transcriptomics profiles and qPCR indicated that lipid metabolic enzymes, including fatty acid synthase (FAS), the elongase of very-long-chain fatty acids (ELO), fatty acid desaturase (FAD), and phospholipase (PL) genes, were not overexpressed in THG-R. Among the twelve thioesterase genes, only MpTHEM6a was significantly upregulated in THG-R. Knocking down the expression of MpTHEM6a in THG-R significantly increased the toxicity of the three neonicotinoids, reduced the lifespan of adults, and decreased the number of nonviable nymphs produced by female adults. The metabolites AA, (±)11-HETE, and prostaglandin B1 are potential biomarkers in neonicotinoid-resistant M. persicae. MpTHEM6a may become a potential target for combating neonicotinoid-resistant M. persicae. Full article

As oil and gas exploration extends into ultra-deep land and sea environments, developing accurate and efficient hydraulic computation models is essential for improving safe and effective drilling techniques. This paper presents a non-isothermal transient hydraulic computational model developed in MATLAB, which integrates the wellbore temperature and flow fields to simulate temperature, pressure, and phase distributions during gas-liquid-solid three-phase flow in deep wells with large annular ratios. Through example calculations, we examine the effects of the annular ratio and convective heat transfer coefficient on wellbore flow. Results indicate that increasing the annular ratio decreases bottom-hole temperature and pressure; specifically, increasing the annular ratio from 1.5 to 3.5 results in approximately a 10% reduction in pressure and a temperature drop of over 50 K. Additionally, when considering convective heat transfer in the drilling fluid, wellbore temperature increases gradually with depth, peaking at about 1/8 of the total well depth. These findings provide theoretical guidance for designing drilling programs and selecting well control strategies for ultra-deep wells. Full article

The genetic regulation of goose meat quality traits remains relatively unexplored, and the underlying mechanisms are yet to be elucidated. This study aims to employ single nucleotide polymorphism (SNP) genotyping in conjunction with genome-wide association studies (GWAS) to investigate critical candidate regions and genes associated with the pH trait of meat in Sichuan white geese. A cohort of 203 healthy male Sichuan white geese was randomly selected and slaughtered at 70 days of age. Measurements were taken of meat pH, growth parameters, body dimensions, and post-slaughter traits. High-throughput sequencing on the Illumina HiSeq X Ten platform facilitated gene resequencing and SNP evaluation, and GWAS was employed to detect key genes within quantitative trait loci (QTL) intervals. The sequencing of 203 individuals yielded a total of 2601.19 Gb of genomic data, with an average sequencing depth of 10.89×. Through GWAS analysis, a total of 30 SNPs associated with pH were identified. These SNPs were identified on multiple chromosomes, including on chromosome 17 (chr: 23.57–23.68 Mb) and chromosome 13 (chr13: 31.52–31.61 Mb). By annotating these associated SNPs, nine candidate genes (including C19L2, AMFR, POL, RERGL, ZN484, GMDS, WAC) associated with the pH of goose meat were identified. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) genotyping of 10 SNPs centered on these nine candidate genes was confirmed. GO enrichment analysis revealed that genes within 1 Mb of the associated SNPs are significantly enriched in pathways involved in lymphocyte activation, in response to hydrogen peroxide, Salmonella infection, and other metabolic processes. This study explores the gene regulatory pathways influencing pH traits in goose meat and provides molecular markers for enhancing meat quality. These findings are expected to facilitate the advancement of molecular breeding programs in geese. Full article

Accurate estimation of gross primary production (GPP) of paddy rice fields is essential for understanding cropland carbon cycles, yet remains challenging due to spatial heterogeneity. In this study, we integrated high-resolution unmanned aerial vehicle (UAV) imagery into a leaf biochemical properties-based model for improving GPP estimation. The key parameter, maximum carboxylation rate at the top of the canopy ($V_{cmax,0}^{25}$), was quantified using various spatial information representation methods, including mean (μ_ref) and standard deviation (σ_ref) of reflectance, gray-level co-occurrence matrix (GLCM)-based features, local binary pattern histogram (LBPH), and convolutional neural networks (CNNs). Our models were evaluated using a two-year eddy covariance (EC) system and UAV measurements. The result shows that incorporating spatial information can vastly improve the accuracy of $V_{cmax,0}^{25}$ and GPP estimation. CNN methods achieved the best $V_{cmax,0}^{25}$ estimation, with an R of 0.94, an RMSE of 19.44 μmol m⁻² s⁻¹, and an MdAPE of 11%, and further produced highly accurate GPP estimates, with an R of 0.92, an RMSE of 6.5 μmol m⁻² s⁻¹, and an MdAPE of 23%. The μ_ref-GLCM texture features and μ_ref-LBPH joint-driven models also gave promising results. However, σ_ref contributed less to $V_{cmax,0}^{25}$ estimation. The Shapley value analysis revealed that the contribution of input features varied considerably across different models. The CNN model focused on nir and red-edge bands and paid much attention to the subregion with high spatial heterogeneity. The μ_ref-LBPH joint-driven model mainly prioritized reflectance information. The μ_ref-GLCM-based features joint-driven model emphasized the role of GLCM texture indices. As the first study to leverage the spatial information from high-resolution UAV imagery for GPP estimation, our work underscores the critical role of spatial information and provides new insight into monitoring the carbon cycle. Full article