Search Results (4,256)

Oocyte quality determines fertilization success during the reproductive period of fish and is affected by a key intrinsic factor: the level of lipid deposition in the yolk. In this study, lipidomics was used to characterize lipid profiles of adipose tissue, liver, serum and ovary to clarify divergent hepatic lipid allocation to fat depots versus ovary in Sichuan taimen (Hucho bleekeri). The results showed that glycerophospholipids (GPs) constituted the most diverse lipid class across all four tissues, with phosphatidylcholine (PC) being the most abundant in each tissue. Relative to adipose tissue, liver, and serum, the ovary exhibited significant enrichment of PC and phosphatidylethanolamine (PE) and higher accumulation of docosahexaenoic acid (DHA)- and arachidonic acid (ARA)-containing GPs and triacylglycerols (TGs), as well as enrichment in TGs, diacylglycerols (DGs), and cardiolipin (CL), compared to adipose tissue. The expression levels of fads6, elovl2, elovl5, dgat1b, dgat2, pparα, nfyb, and fabp7 were higher in the liver, while lpcat1 was highly expressed specifically in the ovary. The results of this study demonstrate that long-chain polyunsaturated fatty acids (LC-PUFAs) exhibited selective enrichment in the ovary, which facilitates yolk lipid deposition and provides structural and energetic support for oocyte development and early embryonic development. From a lipidomic perspective, this study reveals the regulatory characteristics underlying ovarian yolk deposition in H. bleekeri, providing important evidence for understanding the mechanisms of egg quality formation as well as a theoretical basis for broodstock management, artificial propagation, and the improvement of egg and larval quality. Full article

Grain trade connects regions with different land endowments and can help relieve pressure on productive cultivated land. This study constructs a modified cultivated land pressure index incorporating a standardized land productivity coefficient to account for regional variations in land quality. Using provincial-level panel data for 30 regions in China from 2003 to 2020 and a two-way fixed-effects model, we investigate the association between grain import substitution and cultivated land pressure. (1) The virtual land calculations show that soybean had the highest virtual land content among the four major crops, with a national average of 0.554 ha/t, approximately three times that of rice. The virtual land content of soybean, wheat, rice, and maize declined by 20.25–25.76% during the study period, indicating continuous improvement in land-use efficiency. (2) From 2003 to 2020, cultivated land pressure showed clear regional disparities: the Northeast exhibited a gradual decline to moderate levels, and South China and the Middle–Lower Yangtze River regions increased from moderate to high pressure, while the Huang–Huai–Hai Region remained persistently high, and the Southwest remained at moderate levels. (3) Grain import substitution is significantly associated with lower cultivated land pressure, suggesting that imports may contribute to easing domestic land constraints; each additional 100,000 hectares of equivalent domestic cultivated land saved is associated with a reduction of 0.049 in the pressure index. The pressure-alleviating effect is stronger in northern regions and major grain-producing areas than in southern and non-major producing regions. (4) Spatial econometric analysis indicates positive spatial dependence, with increased grain import substitution in one region linked to lower cultivated land pressure in neighboring provinces. This study refines the conventional cultivated land pressure index and provides a framework for assessing both the direct and spillover effects of grain imports on domestic land resources. The findings underscore the potential of grain trade to support sustainable land use and regional resource allocation. Full article

Food security is a strategic national priority, yet the expansion of non-grain production of cultivated land (NGPC) poses a substantial threat to grain production capacity. This paper investigates whether agricultural new quality productive forces (ANQPFs)—as a potential high-quality solution to food security challenges—can effectively mitigate NGPC. Conceptually, while ANQPF may either promote or inhibit NGPC, its net effect remains indeterminate. Initially, an optimal decision-making model is developed to theoretically examine the influence of ANQPF on land-use strategies. Aligning with theoretical predictions, empirical estimates from two-way fixed effects models using Yangtze River Basin panel data (2013–2023) demonstrate that ANQPF significantly mitigates NGPC. These results are resilient to a battery of robustness and endogeneity tests. Mechanism analysis indicates that this effect operates through the substitution of traditional labor and the expansion of socialized services tailored to grain crops. This inhibitory effect is found to be more pronounced in major grain-producing regions and less developed areas. Notably, threshold regression reveals a non-linear relationship: the capacity of ANQPF to stabilize grain production diminishes as per capita GDP surpasses a critical threshold, exhibiting a pattern of diminishing marginal returns. The findings suggest that while ANQPF initially inhibits the shift toward non-grain production, its effectiveness is contingent and stage-dependent. This underscores the need for differentiated policy interventions that integrate technological innovation with institutional and economic support to safeguard food security. Full article

Differential fecundity in goats is a complex trait governed by coordinated molecular regulation across reproductive and endocrine tissues. In this study, we performed integrated metabolomic profiling of follicular fluid, serum, thyroid tissue, and uterine luminal fluid together with transcriptomic sequencing of follicular, thyroid, and uterine horn tissues from high-fecundity (HF) and low-fecundity (LF) Yangtze River Delta White goats. In addition, weighted gene co-expression network analysis (WGCNA) was conducted to elucidate the molecular mechanisms underlying differential litter size. High-fecundity goats exhibited enhanced follicular steroidogenesis, superior corpus luteum function, and more stable hypothalamic–pituitary–thyroid (HPT) axis activity, accompanied by increased uterine gland density and greater myometrial thickness. Metabolomic profiling identified 6640 metabolites displaying tissue-specific differential abundance patterns. Pathway enrichment analysis highlighted steroid hormone biosynthesis and energy metabolism in follicular fluid, PPAR signaling and tyrosine metabolism in thyroid tissue, and glycerophospholipid and one-carbon metabolism in uterine luminal fluid as major pathways associated with fecundity. Transcriptomic analysis identified 1596 differentially expressed genes (DEGs), including 20 genes shared across all examined tissues, constituting a systemic molecular signature associated with fecundity. WGCNA further revealed three functional tissue axes associated with follicular development (ELOVL4, INHA, NR5A2), thyroid endocrine regulation (GRHL2, NAPRT), and uterine receptivity (RSPO1, AGTR2, PTGER3). Low-fecundity-associated modules were predominantly concentrated in follicular and thyroid tissues, whereas the high-fecundity-specific module was mainly enriched in uterine horn. These findings provide a multi-tissue molecular framework underlying differential fecundity in goats and identify candidate hub genes and metabolites that may serve as candidate biomarkers for fecundity assessment and selective breeding programs. Full article

The accurate classification of seabed sediment and benthic covers in shallow-water environments remains a key challenge for marine activities and oceanographic research. However, coastal areas of shallow waters are influenced by complex dynamic environments, making it difficult to obtain authentic sediment and benthic-cover samples. Therefore, to address the problem of few-shot classification of seabed sediment and benthic covers, a few-shot classification algorithm of seabed sediment and benthic covers based on the fusion model of airborne LiDAR bathymetry (ALB) and multispectral images is proposed in this article. Based on the extracted features, a scale-invariant feature transform-progressive sample consensus (SIFT-PROSAC) algorithm and perspective transform model were constructed to achieve feature fusion. Then, multi-modal feature selection is realized using a formal concept analysis-Relief-F (FCA-Relief-F) algorithm. Finally, a graph attention network-prototype network (GAT-PN) model was established to classify five types of sediment and benthic cover (coral reef, stone, sand, vegetation, and coastal zone). To validate the effectiveness of the proposed method, experimental data from actual measurements at Ganquan Island in the Xisha Islands of China were used. Compared to other classical classifiers, the GAT-PN algorithm achieves a higher classification accuracy, with an overall accuracy (OA) and Kappa coefficient of 97.50% and 0.97, respectively. The findings of this study provide effective technical support for marine engineering and related fields. Full article

Promoting the coordinated development of urban resilience (Ur) and urban land use efficiency (Ulue) is key to solving regional sustainable development challenges. Based on panel data of relevant indicators from the Yangtze River Economic Belt (YREB) for the period 2011–2024, this study employs the coupling coordination degree model, kernel density estimation, and exploratory spatial analysis tools to analyze the spatiotemporal differentiation characteristics and spatial correlation of the coupling coordination degree between Ur and Ulue (Uucc). And the spatial patterns of Uucc driving factors are investigated using the Geographically Weighted Regression (GWR) method. The results indicate: (1) In terms of the temporal dimension, the Uucc in the YREB shows an upward trend, with its level continuously improving. The number of cities with higher Uucc levels gradually increases, exhibiting multi-center and multi-layered characteristics. (2) In the dimension of space, Uucc exhibits strong spatial correlation. LISA high-value clusters are concentrated in the downstream region of the YREB, while low-value clusters are found in the upstream and midstream regions. The spatial clustering presents a pattern of “large dispersion, small agglomeration”. (3) The driving factors of Uucc display significant spatial heterogeneity. Urbanization, government regulation capacity and technological innovation are the dominant drivers in the downstream region. Urbanization has a significantly positive effect on Uucc, while its impact gradually weakens from the downstream to the midstream and upstream regions. Urbanization and openness level are the dominant drivers in the midstream region. This study provides references for governments to formulate differentiated policy for different regions. Full article

Oysters, as sessile organisms, are highly influenced by environmental conditions affecting their growth and reproduction. Therefore, unfavorable conditions can directly compromise the effectiveness of oyster reef restoration efforts. The study applied the dynamic energy budget (DEB) theory to model the growth of the Suminoe oyster (Crassostrea ariakensis) and estimated the model’s main parameters through linear and nonlinear regression methods. Meanwhile, the parameters of the existing DEB models for the Pacific oyster (Crassostrea gigas) and the Portuguese oyster (Crassostrea angulata) were optimized to improve the model performance. Model accuracy was confirmed by comparing the simulated and observed values of shell height and wet weight for three oyster species. The validated models were subsequently applied to three distinct habitats: Qianhu Bay, the Yangtze River Estuary, and Jiaozhou Bay, to simulate the individual dynamic growth and survival processes of the three oyster species. The simulations of shell height and wet weight for the three oyster species showed strong agreement with observations, with a mean coefficient of determination (R²) of 0.98. The mean NRMSE value of the three models was 0.16, indicating low model-prediction error. The simulation of various habitat scenarios suggested that C. ariakensis exhibited faster growth in the Yangtze River Estuary and Qianhu Bay, and C. gigas in the Yangtze River Estuary. Additionally, C. angulata experienced mortality in the Yangtze River Estuary (February) and Jiaozhou Bay (January). The findings of this study can provide scientific guidance on selecting species for oyster reefs across various marine environments to effectively enhance their ecological restoration outcomes. Full article

Visual perception is an important component of close-range maritime situational awareness, particularly when conventional sources such as AIS and radar are delayed, incomplete, or unavailable. Ship wakes provide motion-related visual cues, but their segmentation remains difficult because wake regions are elongated, weakly textured, and frequently mixed with water-surface clutter. This study develops Shipwake-YOLO, a wake-oriented adaptation of YOLOv9-Seg for ship and wake instance segmentation in inland-waterway images. The task is formulated as visual navigational-state cue extraction rather than validated future manoeuvre prediction. The model segments hull and wake instances and provides mask-derived spatial cues for possible downstream state interpretation. The architecture introduces iAFF into cross-scale feature fusion, adapts the high-level SPPELAN aggregation block with SAConv-enhanced convolution, replaces selected downsampling paths with iSACADown, and adopts MPD-IoU as the bounding-box regression loss. On a 2100-image dataset collected from the Wuhu Channel of the Yangtze River, Shipwake-YOLO improves Box-mAP@50 from 77.7% to 84.6% and Mask-mAP@50 from 67.6% to 79.8% relative to the YOLOv9-Seg baseline. Under stricter IoU thresholds, the model reaches 48.9 in Box-mAP@[0.50:0.95] and 46.2 in Mask-mAP@[0.50:0.95]. The parameter count is reduced by 7.5%, and GFLOPs decrease from 144.2 to 137.1. These results indicate that the proposed adaptation improves ship-wake perception within the collected inland-waterway setting and provides a visual basis for downstream navigational-state estimation. Full article

The Tibetan Plateau sustains major Asian rivers through extensive cryospheric resources. However, hydrological associations of frozen ground degradation on downstream water availability remain insufficiently quantified. This study presents a preliminary assessment of thermal dynamics of frozen ground in the Yangtze–Yellow River source regions and their hydrological associations with the western Sichuan basins during 1961–2017. Using the near-surface ground freezing index (GFI) as a proxy indicator, we quantified contrasting streamflow responses between the Yangtze River source region (YaSR) and Yellow River source region (YeSR), and their connections with four major rivers in the western Sichuan basins. Results reveal divergent streamflow responses across four rivers, with predominantly positive anomalies despite widespread precipitation decline since the 2000s. As a permafrost-dominated basin, the YaSR exhibits enhanced streamflow generation, with contributions increasing from 6.63% to 31.31% as degradation intensifies. Conversely, the YeSR, mainly occupied by seasonally frozen ground, shows immediate streamflow attenuation that diminishes from 65.71% to 13.86% as degradation advances. The YaSR exhibits statistically significant positive associations with Jinsha and Yalong streamflows, while the YeSR develops significant statistical associations with Min River variability despite limited physical connectivity. These findings highlight the importance of frozen ground dynamics in regional water resource assessments under continued climate change. Full article

Thermophilic cyanobacteria successfully colonize thermal gradients within hot springs, implying evolved mechanisms to cope with temperature-induced oxidative stress. Although polyphosphate (polyP) is known to contribute to oxidative stress resistance, its specific role in thermophilic cyanobacteria remains poorly understood. To address this, this study established a temperature gradient (30–70 °C) and used phloretin (polyP synthesis inhibitor) plus exogenous polyP to investigate polyP metabolism, redox homeostasis, photosynthetic function, and growth of Thermosynechococcus sp. FJSJ-1 from hot spring. The results show that temperature fluctuations specifically induce polyP accumulation, whereas inhibiting polyP synthesis sharply elevates reactive oxygen species (ROS) and overloads intrinsic defenses including superoxide dismutase, catalase, glutathione, and heat shock proteins. Crucially, exogenous polyP rescued phloretin-induced oxidative damage and growth inhibition. PolyP mitigates oxidative damage not by direct ROS scavenging but by integrating and reinforcing endogenous antioxidant network. This protective effect in turn safeguards photosystem II from oxidative attack, thereby preserving photosynthetic pigment stability, phycobiliprotein content, and electron transport efficiency. Taken together, polyP contributes to temperature adaptability in Thermosynechococcus sp. FJSJ-1 by coordinating antioxidant defense. This study elucidates a key molecular strategy for thriving across temperature ranges in geothermal ecosystems, advancing microbial adaptation knowledge and providing a theoretical basis for engineering thermotolerant strains for bioremediation and biofuel production. Full article

Achieving the coordinated development of the digital economy (DE), the tourism industry (TI) and the ecological environment (EE) is of great significance for regional sustainable development. This paper constructs a comprehensive evaluation index system for the digital economy–tourism industry–ecological environment (DTE) complex system. Indicator weights are determined via the entropy method, and the comprehensive development levels of the three subsystems in the Yangtze River Delta (YRD) region from 2010 to 2023 are systematically assessed. Based on this, the coupling coordination degree model is applied to measure the coordination of the DTE system, and the obstacle degree model is employed to identify the key factors restricting its coupling coordinated development. The results show the following: (1) From 2010 to 2023, the overall level of comprehensive development of the DE and EE in the YRD showed an upward trend, while the TI declined significantly during 2020–2022 due to the COVID-19 pandemic. (2) In terms of temporal evolution, the coupling coordination degree rose from 0.434 to 0.676 between 2010 and 2019, steadily improving from near disorder to primary coordination; although there were fluctuations between 2020 and 2023, it remained stable at a primary coordination level. Spatially, the region exhibited a “higher in the east, lower in the west” pattern. (3) From 2010 to 2019, the primary bottleneck in coordinated development stemmed from the DE subsystem; after 2020, the degree of constraints in the TI rose rapidly, creating a dual-system constraint pattern where the DE and the TI coexist. This study provides theoretical insights and practical recommendations for fostering positive DTE interactions in the YRD and offers valuable experience for other regions. This study has limitations regarding its research scale and indicator system, and it does not account for external influencing factors. Future research could adopt municipal or county-level analyses, apply causal inference methods such as panel Granger causality and system GMM, refine the evaluation index system, integrate internal and external factors, and thoroughly analyze the underlying mechanisms governing interactions within the DTE system. Full article

Enhancing urban carbon productivity (UCP) is crucial for achieving the dual carbon goals in China. This study investigates the spatiotemporal patterns and underlying drivers of UCP in the Yangtze River Economic Belt (YREB) from 2010 and 2020. Utilizing a comprehensive dataset of 110 cities, we employ kernel density estimation, spatial autocorrelation analysis, and the Spatial Durbin Model (SDM). The results reveal a significant overall improvement in UCP alongside intensified internal disparities and a fundamental spatial restructuring—from a monocentric eastern-led pattern to a multipolar network driven by the Yangtze River Delta, middle Yangtze, and Chengdu-Chongqing agglomerations. The SDM decomposition reveals a shift in core drivers towards green technological innovation and advanced industrial structure, while energy consumption remains the primary constraint. Crucially, complex spatial spillover effects are identified: factors like advanced industrial structure and digital governance are associated with positive synergistic spillovers, whereas government intervention (government public budget expenditure) and urban sprawl exhibit negative competitive spillovers, collectively corresponding to the polarized regional pattern. Furthermore, urban form shows strong spatial externalities: urban compactness is linked to a “local-neighborhood” double dividend, while urban sprawl is associated with a “local-neighborhood” double curse. The influence of digital factors appears to evolve from early widespread spillovers to later localized deepening. The findings suggest the necessity of implementing spatially differentiated policies, strengthening regional collaborative governance to manage spatial externalities, and promoting compact regional spatial planning to foster synergistic and equitable low-carbon transitions across the YREB. Full article

Fine-scale evidence remains scarce regarding where ecological quality has improved or deteriorated in the Yangtze River Delta (YRD) and which landscape conditions are associated with these trajectories. We developed a 1 km² hexagon-based diagnostic framework integrating the Remote Sensing Ecological Index (RSEI), Sen–Mann–Kendall trend analysis, Local Moran’s I clustering, recurrence-based ecological stress typology, and XGBoost–SHAP interpretation for 2000–2025. Annual RSEI was standardized by year to capture relative trajectories of ecological quality rather than absolute change under a fixed loading system. The regional mean RSEI fluctuated markedly and declined only slightly, from 0.639 in 2000 to 0.632 in 2025, suggesting that long-term ecological change was nonlinear. At the hexagon scale, 64.77% of valid units showed positive RSEI trends, with significant improvement covering 15.08% of units and significant degradation covering 5.47%. Local Moran’s I identified distinct High–High and Low–Low clusters; persistent low-quality clusters and stable high-quality areas accounted for 10.0% and 7.8% of valid hexagons, respectively. XGBoost–SHAP results indicated statistical associations between RSEI trends and soil moisture, elevation, impervious surface change, and nighttime light change, rather than direct causal effects. This framework provides a spatially explicit basis for identifying priority monitoring areas, ecological stress zones, and differentiated land management units across rapidly urbanizing megaregions. Full article

Promoting the coordinated development of digitalization and greening has become an important pathway for firms to achieve high-quality growth. Using panel data for A-share listed firms in China’s Yangtze River Basin from 2010 to 2022, this study examines the effect of supply chain innovation policy on firms’ digital–green development. We measure the synergy between digitalization and greening using a composite system synergy approach and identify the policy effect through a quasi-natural experiment based on the supply chain innovation policy, combined with a synthetic difference-in-differences model. The results show that the policy significantly improves the coordinated development of firm digitalization and greening, and the findings remain robust across a series of tests. Mechanism analysis indicates that this effect operates through three channels: easing financing constraints, increasing supply chain diversification, and promoting industrial chain modernization. Moderating effect tests further show that supply chain efficiency, supply chain resilience, and entrepreneurship strengthen the policy’s positive effect on digital–green development. Heterogeneity analysis suggests that the policy effect varies systematically with firm size, market competitiveness, and information asymmetry. This study provides micro-level evidence on how supply chain innovation policy can promote firms’ digital–green transformation and offers useful implications for policies aimed at improving firm competitiveness and supporting sustainable development. Full article

The Houpoea officinalis flower (HOF) represents an underutilized sustainable bio-resource. This study systematically evaluated its potential using an ethanol-based green extraction process optimized by Response Surface Methodology, with the optimal conditions consisting of approximately 50% ethanol, a solvent-to-solid ratio of 54 mL/g, and an extraction time of 31 min. Chemical profiling across four developmental stages—S1 (Bud), S2 (Bud swelling), S3 (Initial flowering), and S4 (Full bloom)—suggested magnolol and honokiol as the major phenolic compounds, showing a trend of decline during early development followed by an increase at the S4 stage. A significant positive correlation was observed between total phenolic content and antioxidant activity, and the S1 stage extract displayed the strongest antioxidant capacity in multiple in vitro assays. Network pharmacology analysis predicted oxidative stress-related targets and pathways, with TP53, AKT1, IL6, BCL2, and CASP3 recognized as key hub genes. Molecular docking further predicted favorable binding interactions between major HOF phenolics and these target proteins. Collectively, these findings reveal the multi-target antioxidant potential of HOF and provide evidence supporting its potential role in antioxidant-related traditional applications based on predicted mechanisms. Moreover, HOF, particularly at the S1 developmental stage, shows promise as a sustainable source of natural antioxidants and functional ingredients, promoting the high-value utilization of agricultural by-products. Full article