Search Results (2,095)

1-Deoxy-D-xylulose-5-phosphate synthase (DXS) serves as the initial rate-limiting enzyme in the methylerythritol phosphate (MEP) pathway, governing the biosynthesis of precursors for photosynthetic pigments and terpenoids. In this study, the LaDXS2-2 gene was cloned and functionally characterized in lavender (Lavandula angustifolia). The full-length coding sequence (CDS) of LaDXS2-2 spans 2178 base pairs, encoding a protein of 725 amino acids. Phylogenetic analysis revealed that LaDXS2-2 is most closely related to the DXS from Salvia miltiorrhiza. Expression profiling demonstrated that LaDXS2-2 was highly expressed in flower buds, and its transcript levels were significantly upregulated (p < 0.05) in response to ethephon, high light intensity, and low temperature, while exhibiting tissue-specific responses to gibberellin application. Subcellular localization assays confirmed LaDXS2-2 is targeted to the chloroplast. Heterologous overexpression of LaDXS2-2 in tobacco resulted in a marked increase in photosynthetic pigment content, enhanced the actual photochemical efficiency of photosystem II [Y(II)], and reduced non-photochemical quenching (NPQ). Integrated transcriptomic and metabolomic analyses further revealed that LaDXS2-2 overexpression activated the diterpenoid biosynthesis pathway and upregulated amino acid metabolism as well as the TCA cycle, while competitively suppressing phenylpropanoid and flavonoid biosynthesis pathways. These findings indicate that LaDXS2-2 not only enhances photosynthetic efficiency by promoting the synthesis of photosynthetic pigments but also suggests a potential role in influencing primary carbon and nitrogen metabolism, as inferred from transcriptomic and metabolomic data. This functionality may ultimately influence plant growth and metabolic homeostasis. Overall, this study provides a theoretical foundation for the synergistic improvement of photosynthetic efficiency and secondary metabolism in crops. Full article

Introduction: College student-athletes must often balance academic responsibilities with intensive training and competition, placing them under considerable pressure and potentially increasing their risk of mental health difficulties. Against this background, the present study focused on the link between mindfulness and psychological distress and examined whether cognitive reappraisal and subjective vitality were statistically involved in this association as indirect associations. Methods: Participants were 430 college student-athletes recruited from five universities in Hunan Province, China. Using a cross-sectional survey design, the hypothesized model was tested using structural equation modeling in AMOS 23.0, and indirect associations were examined with bootstrap analysis based on 5000 resamples. Results: Mindfulness was positively associated with both cognitive reappraisal and subjective vitality. Cognitive reappraisal was positively associated with subjective vitality but negatively associated with psychological distress. Subjective vitality also showed a negative association with distress. Moreover, mindfulness showed an indirect association with lower distress through cognitive reappraisal and subjective vitality. Discussion: The findings may contribute to a better understanding of the psychological correlates associated with mental health in college student-athletes. They also suggest that mindfulness-related psychological resources may be associated with lower distress and may help guide future longitudinal and intervention research in this group. Full article

Background and Objectives: Water polo (WP) is a high-intensity, intermittent aquatic team sport that has been extensively investigated within sports science. While contemporary literature has examined the body composition and morphological characteristics of elite and international WP players, this study aimed to define the general body composition profile of world-class WP players and determine position-specific differences. Methods: The study involved 72 national team players from Serbia, Croatia, Greece, and Italy who participated in the Olympic Games, World Championships, or European Championships. Participants’ body composition was measured using the InBody 720 multichannel bioimpedance method. Ten different variables were examined to assess body structure regarding contractile and ballast components. Results: MANOVA revealed statistically significant differences in body composition across playing positions (Wilks’ lambda = 0.239, p < 0.000, η²_p = 0.402). The variables that had the greatest impact on the difference were: body mass, body fat and body mass index with the 47.0, 44.4, and 43.7% of explained total variance of the impact on the differences (p = 0.000), respectively. Conclusions: world-class WP players assigned to different playing positions differ significantly in body composition. These positional profiles should be considered in talent identification, selection procedures, training, and nutritional strategies to optimize performance models, considering the future evolution of the game at the highest competitive level. Coaches could use this information to initially select players for different specific positions based on anthropometric and body composition criteria. Full article

Environmental taxation constitutes a key instrument of climate policy and plays an increasingly important role in decentralised governance systems. Using Spain as an empirical setting characterised by high fiscal decentralisation and pronounced territorial heterogeneity, we analyse the determinants of regional environmental taxation, accounting for both internal regional conditions and cross-regional policy interaction. Employing spatial panel econometric techniques, we provide robust evidence of spatial interaction and temporal persistence in regional environmental taxation at both the intensive and extensive margins. We also find that regional environmental taxation depends not only on domestic economic, institutional, and political characteristics, but also on those of neighbouring regions. These patterns are consistent with key theoretical mechanisms in fiscal federalism and public economics, including tax competition, yardstick competition, the double dividend hypothesis, NIMBY-type responses, and development–environment dynamics. Fur-ther analysis at the intensive margin reveals adjustment patterns consistent primarily with upward dynamics, although some evidence of downward responses is also found. In particular, upward adjustments appear to be more systematic, while downward responses are limited to regions with relatively lower environmental taxation. This asymmetry sug-gests that competitive pressures do not operate uniformly across jurisdictions. From a sustainability and governance perspective, the findings show that environmental tax policies in decentralised systems are shaped by strategic inter-regional interdependence, influencing the trajectories of regional sustainability transitions rather than reflecting isolated policy choices. Full article

Background: Football is an intermittent sport characterized by high physical and physiological demands, which may be influenced by the competitive level. Understanding differences in match load is fundamental for optimizing training planning, fatigue management, and athlete performance and injury prevention. This study aimed to evaluate and compare external and internal load in senior football players in Portugal across five distinct competitive levels. Methods: Wimu Pro^TM (Hudl, Lincoln, NE, USA) and Garmin Heart Rate bands (Garmin International Inc., Olathe, KS, USA) were used to quantify and evaluate the external and internal load of the players. A total of 96 athletes were assessed, with ages ranging from 19 to 36 years (mean: 24.28 ± 4.72), who were divided into five competition levels (1st Division (n = 19), 2nd Division (n = 21), 3rd Division (n = 14), 4th Division (n = 20), and Regional Division (n = 22). Results: Significant differences were observed between competitive levels across several external load variables (p > 0.001). The 3rd Division and 4th Division showed higher values in variables associated with reactive and high-intensity actions (p < 0.001; effect size: 0.287), whereas the 2nd Division exhibited a more controlled load profile. Regarding internal load, significant differences were only observed in average heart rate during the second half (p = 0.043; effect size: 0.085), indicating distinct capacities to maintain physiological intensity under fatigue. Conclusions: It can be concluded that competitive level influences load profiles in football, although the differences do not follow a linear pattern. External and internal loads demonstrate greater discriminatory capacity between competitive levels than internal load. Full article

Waste-to-energy (WtE) systems are frequently proposed as complementary waste-management strategies; however, their climate performance depends on the interaction between thermodynamic efficiency, material circularity, and electricity-system characteristics. Existing life-cycle assessments generally provide static comparisons between landfill and WtE but rarely identify the operating conditions under which WtE remains environmentally competitive. To address this gap, a parametric life cycle–energy framework was developed by integrating attributional LCA with an analytical energy model capable of evaluating critical efficiency thresholds under varying recovery rates and electricity-grid conditions. Four representative thermoplastics (PET, HDPE, PP, and LDPE) were evaluated using ReCiPe 2016 Midpoint (H) in SimaPro under Mexican electricity conditions ($E{F}_{\mathrm{grid}}=0.444$ kg CO₂eq/kWh). Results indicate that total life-cycle climate impacts are dominated by upstream polymer production, whereas end-of-life management contributes only marginally to overall GWP. Critical-efficiency analysis revealed strong sensitivity to both recovery rate and electricity-grid carbon intensity. For PET, the minimum efficiency required for WtE to outperform landfill increased from 13.1% to 73.5% across the evaluated scenarios, whereas HDPE remained competitive at efficiencies below 1.3%. Monte Carlo simulations (10,000 realizations) further demonstrated that avoided emissions decline systematically with increasing recovery rates, with LDPE exhibiting the highest mean avoided emissions (1735 kg CO₂eq) and PET the lowest (811 kg CO₂eq). These results demonstrate that WtE climate performance is governed primarily by residual waste availability and electricity-system evolution rather than thermodynamic efficiency alone. Consequently, WtE should be interpreted as a transitional residual-waste management strategy whose long-term climate relevance decreases as material circularity and electricity-grid decarbonization advance. Full article

Polyethylene microplastics (PE-MPs) are ubiquitous constituents of waste activated sludge (WAS), acting as a major land-based source threatening coastal environmental integrity. However, how particle size and dose govern the methanogenic outcome during WAS digestion remains poorly defined. This study evaluated two particle sizes (50 vs. 300 µm) and doses (100 vs. 200 particles/gTS) to elucidate the differential effects of PE-MPs on methane yield and the underlying biological mechanisms. The results show that, while low-dose treatments either slightly inhibited methane yield (RS1) or had no significant effect (RL1), high-dose treatments (RS2 and RL2) achieved a net positive effect, with significant increases of 10.2% (p < 0.05) and 9.0% (p < 0.05) relative to the control, respectively. Nevertheless, RS2 and RL2 achieved methanogenic enhancement via distinctly different biological pathways. RS2 harnessed the stress of reactive oxygen species (ROS) (110.5% of the control) to drive community restructuring and biomass accrual (positive correlation between ROS intensity and total VS, Pearson’s r = 0.99). Key syntrophic and electrogenic taxa (e.g., Syntrophales, Bacteroidetes vadinHA17) exhibited a fully interconnected, decentralized network, thereby achieving tight coupling between hydrolysis and methanogenesis. RL2 leveraged the physical carrier effect to promote granulation and biomass growth, enriching Syntrophobacter to enhance propionate degradation. This culminated in a highly modular, sparse network characterized by localized competitive interactions. Together, dosage governs the net methanogenic effect of PE MPs, whereas particle size dictates the mechanistic routes of action. This work offers a mechanistic framework to optimize energy recovery from PE-MP-contaminated sludge while mitigating secondary environmental risks, providing a science-based strategy for the sustainable management of plastic-laden sludge that reconciles renewable energy recovery with pollution control. Full article

Urban vitality is regarded as a cornerstone of sustainable urban development. While land use mix (LUM) is widely acknowledged for fostering vitality, most empirical evidence relies on mean-effect models, neglecting the heterogeneous impacts across different vitality levels. This overlooks the complex, context-dependent nature of LUM and risks perpetuating one-size-fits-all planning. Based on a theoretical framework that links LUM analysis with contemporary urban revitalization, public governance, and smart city development discussions, this study leverages a Spatial Durbin Quantile Regression (SDQR) framework with multi-source geospatial data from 511 blocks in Ningbo, China, to systematically investigate the distributional heterogeneity of LUM’s effects on urban vitality. We decompose LUM into “diversity”, “proximity”, and “coordination” dimensions, revealing three distinct mechanisms across the vitality spectrum. Results show “coordination” acts as a fundamental “ignite” mechanism, consistently driving vitality across all quantiles, especially in new towns and low-vitality areas. “Diversity” primarily serves as a “boost” mechanism, enhancing vitality in medium-to-high vitality areas, demonstrating a non-linear, conditional effect. Crucially, “proximity” exhibits a novel “cap & siphon” mechanism: its direct effect is often insignificant or negative in low-vitality areas (suggesting structural mismatch), while its significant negative spatial spillover effect (siphon effect) across all quantiles, particularly in low-vitality zones, highlights intense inter-area competition. Furthermore, LUM’s direct effects tend to diminish in high-vitality areas, indicating a saturation or “cap” effect. By revealing these heterogeneous impacts and spatial spillover dynamics, this research refines the boundary conditions of classic mixed-use propositions and provides a differentiated planning paradigm, moving from universal zoning to context-specific, stage-calibrated interventions that address areas based on their current vitality levels, spatial interactions and governance contexts. Full article

Background: Myocardial scar segmentation from late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) images plays an important role in cardiac disease assessment and prognosis evaluation. However, accurate scar annotation is labor-intensive and requires substantial clinical expertise because scar regions are typically small, irregularly shaped, and characterized by ambiguous boundaries. Although scribble supervision provides a more practical alternative to dense annotation by substantially reducing labeling costs, the extreme sparsity of scribbles and the high similarity between scar tissue and surrounding myocardium make accurate weakly supervised segmentation challenging. Methods: To address these challenges, we propose SSMSNet, a novel scribble-supervised framework for myocardial scar segmentation. Specifically, a weakly supervised anatomical segmentation network is first employed to provide reliable myocardial structural priors and suppress irrelevant background interference. Subsequently, a local distance prior map is dynamically generated from scribble annotations, and a corresponding loss is introduced to enhance structural awareness and improve training stability. Meanwhile, by leveraging the spatial correlation between the myocardium and scar regions, teacher–student consistency supervision progressively recovers more complete scar structures from sparse annotations. Furthermore, a detail-aware feature enhancement module strengthens low-level representations through contextual interactions and attention mechanisms, improving the perception of scars with ambiguous boundaries. Results: Extensive experiments conducted on two public cardiac pathology datasets demonstrate that the proposed framework consistently outperforms state-of-the-art scribble-supervised methods and achieves competitive performance compared with fully supervised methods. Conclusions: The proposed SSMSNet effectively alleviates the limitations imposed by scribble annotations by integrating anatomical guidance, local distance priors, and consistency learning. These findings suggest that the framework provides an effective and annotation-efficient solution for myocardial scar segmentation in LGE CMR images. Full article

LiDAR-based place recognition is critical for long-term autonomous navigation in Global Navigation Satellite System (GNSS)-denied environments, yet existing methods struggle to balance accuracy and efficiency under substantial yaw rotations. This paper proposes a robust framework based on a multi-channel polar bird’s-eye-view (BEV) representation. Under yaw-dominated revisits, the polar BEV image transforms yaw rotation into cyclic column shifts, providing a useful structural prior for rotation-equivariant feature extraction. Raw point clouds are projected onto polar BEV grids encoding density, height, and intensity. A rotation-equivariant feature extractor comprising a Radial Compression Module and a rotation-equivariant Transformer module captures long-range azimuthal dependencies via Conditional Positional Encoding and Circular Relative-Position Bias. The equivariant features are aggregated by NetVLAD into a compact global descriptor, trained end-to-end with a hard-example mining triplet loss. Extensive experiments on the public KITTI and NCLT datasets, as well as our self-constructed LiDAR Place Recognition Revisit (LPRR) dataset, demonstrate competitive performance on KITTI and superior performance on NCLT and LPRR among the compared methods. The proposed framework achieves a favorable trade-off between performance and computational cost, and shows promising cross-dataset generalization on the evaluated NCLT and LPRR datasets without fine-tuning. Full article

This paper considers a multi-period two-sided asymmetric information model with infinitely long-lived sellers and short-lived buyers. I assume that two exogenously given qualities are offered in the market. Each period, a consumer, who is uncertain about the quality of the offered product, observes her pairwise matched seller’s price and a noisy signal of quality that cannot be manipulated by the seller. Prices are fixed and it is common knowledge that consumers are not willing to pay a high price for the low-quality product. A matched seller with a low-quality good can choose to be either honest (by charging the lower market price) or dishonest (by charging the higher price). Sellers’ incentives to misrepresent quality depend on how current trade outcomes affect future access to consumer traffic. I show that the strength of the informational role of prices is non-decreasing in the intensity of competition for future consumer traffic in equilibrium and that consumers do not benefit from more intense competition. Full article

Ammonia is an essential high-volume chemical for fertilizer production and other industrial applications, and it is increasingly considered a potential energy carrier; however, its conventional manufacture remains highly energy- and carbon-intensive because it relies predominantly on fossil-based Haber–Bosch (HB) synthesis. This review compares sustainable ammonia-production pathways through the linked dimensions of technology readiness, environmental performance, and economic plausibility across renewable-H${}_2$ HB, biomass- and waste-derived HB routes, electrochemical pathways, photocatalytic and photoelectrochemical systems, plasma-assisted synthesis, biological routes, and chemical looping ammonia synthesis. The analysis reveals a clear divide between pathways that benefit from established industrial infrastructure and those that still depend on unresolved catalytic, materials, or systems-level advances. Renewable-H${}_2$ Haber–Bosch emerges as the most broadly scalable near-term option for large-scale ammonia decarbonization because it combines the highest maturity among low-carbon routes with the strongest techno-economic and life-cycle evidence base. Biomass- and waste-derived Haber–Bosch pathways may become cost-competitive regional complements when low-cost local residues, organic waste, or biomethane is available, feedstock logistics are favorable, and carbon, waste-treatment, or negative-emission credits are included. Overall, sustainable ammonia production is likely to advance through a portfolio of pathways, with near-term progress led by renewable-H${}_2$ HB and longer-term development dependent on improved reactor integration, harmonized assessment methods, and scalable validation. Full article

Understory vegetation communities in chestnut (Castanea sativa L.) forests feature unique biodiversity patterns and high conservation value, yet the complex drivers of these communities remain poorly quantified. This study investigates the combined effects of structural, microclimatic, and topographic parameters on understory biodiversity in the mountainous region of Chalkidiki, Northern Greece. Using a nested plot design (n = 30), we integrated analytical in situ microclimatic monitoring with hemispherical photography (HemiView canopy image analysis system) to accurately quantify canopy architecture (canopy cover and solar radiation parameters), while a detailed vegetation inventory of vascular plants was performed to determine plant community structure and composition. Generalized Additive Models (GAMs) were employed to model Shannon Diversity (H’) and a weighted rarity index (RSR) representing complementary aspects of understory biodiversity. Our results reveal that the tree slenderness of the dominant stand serves as a robust proxy for stand competition and compactness. Lower slenderness values, reflecting reduced overstory competition, were significantly associated with enhanced light availability and potentially with microclimatic stability, which in turn supported higher levels of species diversity and rarity. Distinct ecological trends were observed between diversity and rarity. Shannon diversity was highest in closed forest environments characterized by lower temperatures, low stand slenderness values, southern aspects, and lower elevations, with the final model explaining 66.1% of the variance (n = 27). In contrast, species rarity was primarily driven by stand slenderness and low disturbance levels (explaining 54.6% of the variance), with the majority of rare species occurring in undisturbed stands (n = 30). These findings suggest that targeted, low-intensity management for competition promotes structurally stable stands and microclimatic buffering, facilitating the preservation of understory biodiversity. Full article

Traditional olive groves are widely recognised as providers of landscape, environmental and cultural public goods in Mediterranean rural areas, but their long-term economic viability remains uncertain. This study assesses the income gap between traditional, intensive and super-high-density (SHD) olive-growing systems in a representative hill olive-growing area in Tuscany (central Italy), characterised by physical and structural conditions typical of traditional Mediterranean systems. Using a discounted cash-flow framework, the analysis compares long-term financial performance through standard investment appraisal indicators and uses the Equivalent Annual Value (EAV) as a policy-relevant benchmark for calibrating support. The results reveal a clear structural divergence: while intensive and SHD systems achieve higher profitability and faster capital recovery, the traditional system exhibits a persistent income disadvantage under market conditions. The estimated EAV gap amounts to approximately 950 €/ha relative to the intensive system and 3104 €/ha relative to the SHD system—values that represent the additional annual support required to preserve traditional olive groves and prevent abandonment. These values can also be interpreted as the annual private opportunity cost of maintaining traditional olive landscapes rather than converting them to more financially competitive systems. Break-even analysis further shows that the traditional system requires an oil price of at least 9.6 €/kg to achieve economic viability without public support, compared to 6.97 €/kg and 4.13 €/kg for the intensive and SHD systems, respectively. The findings highlight a structural misalignment between private profitability and social value, suggesting that the conservation of traditional olive landscapes cannot rely on market mechanisms alone and requires targeted, evidence-based policy instruments. Full article

The significant growth in e-commerce has brought intense competition to the business sector. Businesses seeking to stand out in this competition are evaluated by customers not only by the quality of the products they sell, but also by their performance on digital platforms. To measure this evaluation, this study analyzed the website performance of 25 e-commerce companies in Türkiye using Multi-Criteria Decision Making (MCDM) methods with eleven technical and user-oriented performance criteria. MAXC (Maximum Criterion) and Skewness Impact Through Distributional Evaluation (SITDE) methods were used to determine the criterion weights of the websites, while CORASO (COmpromise Ranking from Alternative SOlutions) was used to rank the alternatives. According to the results, “total number of visitors” had the highest weight, while “bounce rate” had the lowest weight. According to the CORASO method, the top three performing e-commerce sites were EC1, EC2, and EC3, while the bottom three performing sites were EC11, EC14, and EC20. Full article