Search Results (36,208)

This study examines the modelling and forecasting of South African macroeconomic and financial time series using a comparative framework based on Vector Autoregressive (VAR), Vector Autoregressive Moving Average (VARMA), and GARCH-type models. Quarterly data spanning 1970 to 2024 were analysed to determine GDP growth, exchange rates, interest rates, and household consumption expenditure. VAR and VARMA models were employed to capture conditional mean dynamics, while GARCH, EGARCH, and GJR-GARCH models, including ARMA-GARCH extensions, were used to model volatility behaviour. Optimal model specifications were selected using the Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), Hannan–Quinn Criterion (HQ), and the Extended Cross-Correlation Matrix (ECCM), resulting in the estimation of VAR (4) and VARMA (1,1) models. The results reveal strong dynamic interdependencies among the variables. However, diagnostic tests indicate that the VAR (4) and VARMA (1,1) models do not fully capture the underlying data-generating process, as evidenced by residual autocorrelation, heteroskedasticity, and non-normality. Although the VARMA (1,1) model improved forecasting performance relative to the VAR (4) model, important nonlinear and higher-order dynamics remained unexplained. Volatility modelling revealed substantial persistence and clustering, particularly in exchange rates and interest rates. Initial GARCH, EGARCH, and GJR-GARCH specifications exhibited residual autocorrelation and remaining ARCH effects, suggesting model misspecification. The incorporation of an ARMA (1,1) term into the asymmetric GARCH models significantly improved model adequacy by eliminating residual autocorrelation and heteroskedasticity. Limited evidence of asymmetric volatility effects was found. Overall, the findings demonstrate that GARCH-ARMA specifications provide a more robust framework for modelling South Africa’s macroeconomic and financial dynamics. This study recommends future research incorporating nonlinear, regime-switching, and exogenous-variable models to enhance forecasting accuracy and policy relevance. Full article

To investigate the influence of porosity defects and the strengthening effect of bonded iron-based shape memory alloy (Fe-SMA) plates, fatigue tests were conducted on defect-free, porosity-containing, and Fe-SMA-strengthened U-rib butt-welded specimens. A numerical model considering porosity defects and the bonded Fe-SMA plate was also established and validated against the experimental results. The results show that porosity defects significantly increased the local stress level near the crack. Under a load of 60 kN, the stress at the section 2 mm from the crack edge increased from 98 MPa to 139.5 MPa. Meanwhile, the fatigue life decreased from 260 × 10⁴ cycles to 127 × 10⁴ cycles. After Fe-SMA strengthening, the stress decreased to 75.59 MPa, and the fatigue life increased to 326 × 10⁴ cycles, which was 2.57 times that of the unreinforced defective specimen. The Fe-SMA plate did not change the fatigue crack propagation path but effectively slowed crack growth through local stiffness enhancement and activation-induced pre-compressive stress. Parametric analysis further showed that, among the investigated numerical cases, an activation temperature of 200 °C produced the largest predicted strengthening effect. Increasing the pore diameter from 0.5 mm to 2.0 mm reduced the reinforcement effect from 69.45% to 52.98%, and increasing the crack length from 10 mm to 50 mm reduced it from 65.41% to 35.53%. These results indicate that bonded Fe-SMA plates can effectively improve the fatigue performance of U-rib butt-welded joints with porosity defects, especially when applied before excessive crack growth occurs. Full article

This study examined whether adaptive humor styles, affiliative and self-enhancing, predict the five dimensions of post-traumatic growth (PTG) in a sample of South African undergraduate students who had experienced trauma. A cross-sectional SEM design was used with a criterion sample of 194 South African undergraduate students (72.7% female; M = 21.06 years, SD = 1.84) who had experienced a traumatic event between one and five years before participation. Self-enhancing humor was a significant positive predictor of all five PTG dimensions (Relating to Others, New Possibilities, Personal Strength, Spiritual Change, and Appreciation of Life), with standardized path coefficients ranging from β = 0.324 to β = 0.477. The measurement model demonstrated acceptable fit, though CFI (0.870) fell marginally below the conventional 0.90 threshold, likely due to model complexity. Affiliative humor did not independently predict any PTG dimension, with its zero-order correlations accounted for by shared variance with self-enhancing humor. These findings suggest that the emotion regulation and cognitive reappraisal functions of self-enhancing humor may facilitate growth across multiple domains following trauma, and have implications for therapeutic interventions aimed at promoting PTG. Full article

With the rapid growth of electric vehicles (EVs) and renewable energy generation, Vehicle-to-Grid (V2G) technology has emerged as a promising approach for transforming EVs from passive charging loads into flexible distributed energy storage resources. By enabling bidirectional power exchange between EV batteries and the power grid, V2G can support renewable energy accommodation, peak shaving, demand response, ancillary services, and local grid balancing. This review provides a systematic synthesis of recent advances in V2G systems for renewable energy integration, with particular emphasis on coordinated scheduling, economic mechanisms, battery degradation, and user engagement. First, the technical foundations of V2G are introduced, including Vehicle-to-Everything operating modes, bidirectional charging architecture, aggregation mechanisms, grid-support services, and renewable accommodation pathways. Second, major scheduling strategies are reviewed, including price-based, load-based, renewable-forecast-driven, centralized, distributed, and hybrid approaches. Third, the economic feasibility of V2G is examined from the perspectives of revenue streams, pricing mechanisms, business models, battery aging costs, and compensation schemes. In addition, user participation barriers, such as range anxiety, battery lifetime concerns, loss of control, uncertain financial returns, and data privacy, are discussed. Key challenges related to communication standards, interoperability, cybersecurity, market access, policy design, and pilot-scale validation are also summarized. Finally, future development directions are identified, including AI-based scheduling, aggregator platforms, fleet-scale V2G, degradation-aware optimization, carbon-aware electricity markets, and user-centered participation mechanisms. This review highlights that large-scale V2G deployment requires the integrated coordination of technical scheduling, economic incentives, battery health protection, and user acceptance in renewable-rich power systems. Full article

In modern livestock production, a reliable supply of high-quality forage is essential for sustaining animal productivity and product quality. Although nitrogen (N) fertilization can promote forage growth, excessive N inputs often result in low agronomic nitrogen use efficiency (NAUE) and increased environmental risks. Biochar, owing to its porous structure, high specific surface area, and physicochemical stability, can improve soil physical properties, enhance water and nutrient retention, and regulate soil N availability. However, the mechanisms by which biochar combined with reduced N rate fertilization affects NAUE in artificial grasslands remain insufficiently quantified. A two-year field experiment was conducted at the Grassland Science Experimental Station of Xinjiang Agricultural University on the northern slope of the Tianshan Mountains, Xinjiang, China. Eight treatments were established using a factorial design with two biochar rates (0 and 20 t·ha⁻¹; B0 and B20) and four N application rates (0, 75, 150, and 225 kg·ha⁻¹; N0, N75, N150, and N225). Results showed that biochar application significantly decreased soil bulk density and increased soil water content and electrical conductivity. It also elevated soil total carbon, total nitrogen, total phosphorus, NH₄⁺–N, and NO₃⁻–N concentrations, with B20N150 exhibiting the highest overall nutrient status. Plant community diversity indices did not differ significantly among treatments (p > 0.05), though B20 slightly enhanced Shannon–Wiener and Simpson indices under N0 and N75. Moderate N application significantly increased hay yield, whereas the highest N rate (225 kg·ha⁻¹) did not further improve yield and reduced NAUE. Biochar combined with N75 or N150 improved NAUE, and B20N150 achieved the best balance of high hay yield and high NAUE. Structural equation modeling revealed that soil water content (path coefficient = 0.45), NH₄⁺–N (0.27), and plant community diversity (0.20) were key positive drivers of NAUE, with biochar exerting indirect effects primarily via improving soil water and available N. Collectively, applying 20 t·ha⁻¹ biochar with 150 kg·ha⁻¹ N (B20N150) is recommended as an optimal strategy for N rate reduction and NAUE enhancement in artificial grasslands of arid and semiarid regions. Full article

After EU accession, Croatia has leveraged the advantages of EU membership, such as access to a large market and EU funds, to accelerate economic growth and reduce the development gap in comparison to advanced EU economies. Although EU membership has stimulated economic growth, it has also brought negative effects, such as labor emigration to more developed EU economies with higher wages and increased inflation due to price convergence and the adoption of the Euro. The weak growth of labor productivity in Croatia is a consequence of the slow transformation towards technology-intensive industries, the dominance of traditional labor-intensive sectors such as construction and hospitality, and the rapid growth of employment in the public sector. The novelty of the research lies in applying an input–output model to estimate direct and indirect labor requirements in Croatia, an example of a small, service-oriented economy that, after joining the EU, witnessed a significant increase in final demand. Research is based on the Eurostat FIGARO database. The increase in gross value added across industries during 2015–2024 is separated into price and real growth effects. Analysis indicates that the current Croatian growth model is unsustainable because of high labor requirements and slow productivity growth. Results imply that European Union membership brings many advantages, but if not coupled with an adequate industrial development strategy, economic growth based exclusively on increasing final demand could reach its limits. Labor constraints and continued demand growth without substantial structural changes could result in rising wages and prices rather than real GDP growth. Full article

Dense simultaneous localization and mapping (SLAM) via 3D Gaussian splatting (3DGS) faces memory bottlenecks due to the explosive growth of primitives during long-sequence mapping. We propose SATA-SLAM, a framework featuring spatial-aware truncation and adaptive anti-hallucination. The online front-end maintains a constant memory footprint via a spatial-aware pruning module (SAPM), which employs a survival scoring function that couples primitive opacity with view-frustum projection coverage and a temporal protection window. Subsequently, an anti-hallucination generative refinement module (AGRM) utilizes texture priors from pretrained diffusion models for offline inpainting of residual regions. In addition, an adaptive gating mechanism to verify and suppress AIGC-induced hallucinations caused by pose drift, ensuring multiview consistency. Experiments on the public Replica dataset show that SATA-SLAM improves rendering quality from 12.5 dB to 37.44 dB (averaged over the Replica room0 and office0 scenes) while using only 26% of the original memory, outperforming the unconstrained baseline. This study provides a pathway toward low-power, high-fidelity environmental perception for mobile robots. Full article

Banks must balance deposit stability, loan expansion, and regulatory compliance while operating under liquidity constraints and financial risks. This study presents a mathematical model to examine the dynamics of bank deposits and loans under the influence of liquidity mechanisms and regulatory policies. The model proceeds in three stages: a deterministic nonlinear model, a dynamic optimal control model, and a stochastic model. Under the deterministic model, deposit withdrawals are liquidity-dependent, leading to a feedback mechanism in which liquidity improves deposit stability while financing loan growth. The theoretical results demonstrate the model’s positive and bounded solutions and show the existence and local stability of equilibria. Several parameters are based on regulatory policies or calibrated from Indonesian banking data, while the unknown parameters are estimated using the particle swarm optimization (PSO) algorithm. The results show that the proposed model is capable of fitting and predicting the data and has slightly lower mean absolute percentage errors for in-sample and out-of-sample compared with the benchmark model, and achieves comparable directional forecasting performance based on the index of directionality. Sensitivity analysis shows that the capital adequacy ratio supports lending, whereas an increased reserve requirement limits lending. An optimal control approach is developed by considering the reserve and capital requirements as time-varying policy variables. By applying Pontryagin’s maximum principle, we establish the necessary conditions for optimality. Numerical experiments demonstrate that the optimal control regulation enhances financial ratios, particularly the loan-to-deposit and liquidity ratios, at a reasonable cost. Finally, the stochastic model accounts for random variations in withdrawals and credit risks. Simulation-based observations reveal that although the system becomes more volatile, the mean dynamics are close to the deterministic case. Our framework offers a data-based and analytically tractable approach for studying the dynamics of banking variables and the effects of regulatory policies. The proposed model provides a mathematical tool for assessing the long-term effects of regulatory policies on banking performance and can assist bank managers and regulators in designing strategies that balance lending activity and liquidity resilience. Full article

Understanding the spatiotemporal relationship between agricultural inputs and crop production is essential for sustainable agricultural management. Using provincial panel data from China from 2000 to 2022, this study integrates spatiotemporal analysis with the XGBoost-SHAP model to examine the nonlinear effects of agricultural machinery, fertilizers, pesticides, and plastic films on soybean, cereal, and tuber yields. The results show that China’s agricultural input system shifted around 2015 from input-intensive growth toward green transformation, with fertilizer, pesticide, and plastic-film use declining after this inflection point. Spatially, agricultural inputs and crop production show clear agglomeration and path dependence: machinery is concentrated in northern China, fertilizers and pesticides in eastern intensive farming regions, and plastic-film use in arid and cold regions, while soybean, cereal, and tuber production are mainly concentrated in Northeast China, the Northeast-Huang-Huai-Hai region, and Southwest China, respectively. The SHAP results reveal distinct crop-specific importance rankings and nonlinear threshold patterns. For soybean yield prediction, agricultural plastic film use contributes most strongly to the model output, followed by fertilizer application, pesticide use, and machinery power; its SHAP contribution turns negative beyond approximately 112.4 thousand tons. For cereal yield prediction, machinery power ranks first, followed by fertilizer application, pesticide use, and plastic-film use; its contribution becomes positive beyond approximately 28.34 million kW and then gradually levels off. For tuber yield prediction, fertilizer application is the dominant predictor, followed by pesticide use, machinery power, and plastic-film use; its contribution turns negative beyond approximately 1.35 million tons. These findings indicate that agricultural inputs have crop-specific nonlinear effects, and that input regulation should prioritize the most influential factors for each crop while considering their threshold ranges. The study provides a scientific basis for differentiated, crop-specific, and regionally adaptive agricultural input management. Full article

The rapid growth of the pet-humanisation trend has generated a distinct segment of tourists who regard pets as family members and seek travel experiences that accommodate both human and animal needs. This study examines the causal relationships among service quality, destination image, perceived value, and travel intention among Thai pet-humanising tourists. Using a quantitative approach, data were collected from 280 Thai respondents with experience or interest in pet-friendly tourism and analyzed via Structural Equation Modelling (SEM). The findings indicate that service quality and destination image significantly enhance perceived value, which subsequently exerts the strongest positive effect on travel intention. While service quality directly increases travel intention, destination image demonstrates a significant negative direct effect but a positive indirect effect through perceived value, highlighting a competitive mediation mechanism. By extending value-based behavioural models to this emerging segment, the study suggests that tourism and hospitality operators should prioritise tangible pet-friendly infrastructure and value-enhancing experiences over mere destination image, supporting the strategic development of inclusive pet-friendly destinations. Full article

Optimizing nutrient management is essential for improving the productivity and profitability of perennial bioenergy crops on marginal soils. This study evaluated the effects of mineral fertilization, a humic-based biostimulant, and a titanium-containing micronutrient preparation on the growth, biomass yield, and economic performance of Miscanthus × giganteus grown on acidic low-fertility soil in Western Ukraine from 2022 to 2025. A repeated-measures mixed-model analysis showed significant effects of treatment, year, and treatment × year interaction for the main growth and productivity parameters, indicating a year-dependent fertilization response. Integrated fertilization improved plant height, shoot formation, dry biomass yield, and biofuel output compared with the unfertilized control. The highest mean dry biomass yield was obtained with N₃₀P₃₀K₃₀ + Black Jack, reaching 16.43 t ha⁻¹ and exceeding the control by approximately 40%, while N₃₀P₃₀K₃₀ + Intermag Titan also showed high productivity. Dry biomass yield was strongly associated with plant height, confirming the role of structural development in biomass formation. Economic assessment indicated the highest long-term profitability for N₃₀P₃₀K₃₀ + Black Jack. These findings indicate that integrated fertilization is an effective strategy for sustainable miscanthus biomass production on marginal soils. Full article

Highway corridors are increasingly being discussed not only as zones of ecological disturbance but also as components of regional green infrastructure with potential carbon sequestration functions, yet their long-term evolutionary characteristics and multi-scale associated factors remain insufficiently understood. Using multi-source time-series data from 2000 to 2023, we developed an analytical framework integrating the CASA model, Random Forest, and geographically weighted regression (GWR). To ensure methodological rigor, we implemented a Spatial K-fold Cross-Validation strategy and incorporated Partial Dependence Analysis (PDA) to identify non-linear thresholds. The results indicate that: (1) Vegetation carbon sequestration within Shandong’s highway corridors increased significantly, with total sequestration rising from 5.54 × 10⁶ t in 2000 to 1.55 × 10⁷ t in 2023, representing an average annual growth rate of approximately 5.0%. This growth transitioned from a relatively stable phase to a more rapid growth phase. (2) A clear distance-related ecological pattern was observed. Statistical tests (Kruskal–Wallis H test) confirmed that vegetation carbon sequestration exhibited a significant non-monotonic gradient ($p<0.05$), with a stable peak zone observed 50–100 m from the roadbed. This peak zone is associated with a spatial “trade-off” pattern between the attenuation of traffic-related stressors and roadside ecological management. (3) The observed spatial pattern was associated with a nonlinear coupling of natural background conditions and human disturbance. Precipitation and temperature were the dominant associated factors, while PDA further identified a critical precipitation threshold (~750 mm) and localized tipping points for human interference, with a distinct road-disturbance-sensitive zone evident within 200–500 m. The results suggest that high-standard ecological design and active restoration measures are associated with lower ecological disturbance and higher vegetation carbon sequestration performance in some highway corridors. However, these relationships should be interpreted cautiously, as they may also be influenced by differences in climate background, topography, land-use context, and road construction history. These findings provide empirical evidence to inform differentiated ecological restoration and low-carbon management of traffic corridors. Full article

Using panel data from 282 prefecture-level and above cities in China, this study employs a difference-in-differences (DID) model to examine the impact of the National Sustainable Development Plan for Resource-Based Cities on carbon emission efficiency, as well as its underlying mechanisms and heterogeneous effects. The results indicate that the implementation of the Plan significantly improves carbon emission efficiency. This conclusion remains robust after a series of robustness tests, including the propensity score matching difference-in-differences (PSM-DID) approach. Mechanism analysis further reveals that technological innovation, industrial upgrading, and reductions in energy consumption constitute the primary channels through which the Plan enhances carbon emission efficiency. In addition, economic growth pressure and the degree of marketization exert negative and positive moderating effects, respectively, on the relationship between the Plan and carbon emission efficiency. Heterogeneity analysis shows that the positive effect of the Plan is significant only in resource-based cities located in eastern China, southern China, or southeast of the Hu Huanyong Line. In terms of city size, the positive effect is observed only in medium-sized cities and Type II large cities. Full article

The aquafeed industry is seeking sustainable alternatives to fishmeal, and insect meals are promising candidates. However, quantitative syntheses of their effects on non-fish aquatic animals like shrimp, crabs, turtles, and frogs are limited. This meta-analysis evaluated five insect meals—black soldier fly, Coleoptera, housefly, silkworm, and Orthoptera—on specific growth rate (SGR), weight gain rate (WGR), and feed conversion ratio (FCR). A total of 69 studies (2004–2025) were included. Hedges’ g was pooled using random-effects models, and meta-regressions examined dose–response relationships. Among all categories, only silkworm meal improved or maintained growth, showing no significant negative dose–response relationship. In contrast, black soldier fly and Coleoptera meals impaired growth, with a negative linear dose–response. Subgroup analyses revealed species-specific responses; shrimp, particularly Litopenaeus vannamei, exhibited growth depression, whereas some crab species, including Scylla paramamosain and Eriocheir sinensis, showed tolerance or improved performance. Housefly and Orthoptera meals were evaluated in fewer studies, precluding firm conclusions. Thus, the efficacy of insect meal substitution is jointly determined by insect type and host physiology. Silkworm pupae meal is a favourable fishmeal alternative, while black soldier fly and Coleoptera meals require conservative inclusion limits, especially for shrimp. Full article

The replacement of fishmeal with plant-based ingredients in aquafeeds, while economically and environmentally advantageous, can impair lipid metabolism and liver function in fish due to the lack of specific bioactive compounds such as bile acids (BAs). BAs are amphipathic steroid molecules that facilitate lipid digestion and act as signaling hormones, yet their optimal inclusion levels in conventional, balanced diets for Nile tilapia (Oreochromis niloticus) remain undefined. This study evaluated the effects of dietary BA inclusion on growth performance, feed efficiency, body composition, and serum biochemical parameters of juvenile Nile tilapia (GIFT strain, initial weight 18.04 ± 3.67 g) and estimated the optimal inclusion level. Six isoproteic (320 g kg⁻¹) and isoenergetic (3300 kcal kg⁻¹) plant-based diets were formulated with increasing BAs levels (0, 50, 100, 200, 400, and 600 mg kg⁻¹) and fed to quadruplicate groups for 45 days. Only the Linear Response Plateau (LRP) model converged for weight gain data, estimating the optimal BA level at 479.70 mg kg⁻¹, with a plateau weight gain of 76.60 g. Inclusion of the 50–600 mg kg⁻¹ BAs significantly improved specific growth rate (up to 4.53%), crude protein retention efficiency (up to 81.11%), and whole-body crude protein content (up to 50.52%) compared to the control (p < 0.05). Fish fed 200 mg kg⁻¹ BAs exhibited the highest protein retention and lowest ether extract deposition, indicating a protein sparing effect. Serum lipase activity increased proportionally with BAs levels, while alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were reduced at 400 mg kg⁻¹ BAs, reflecting improved liver health. No mortality was recorded. In conclusion, dietary BAs inclusion enhances growth, protein utilization, and hepatic function in juvenile Nile tilapia fed plant-based diets. The recommended optimal level is 479.70 mg kg⁻¹ (dry matter basis), although significant benefits already occur from 50 mg kg⁻¹. These findings support the strategic use of BAs to improve the sustainability and efficiency of tilapia production. Full article