Search Results (858)

This study investigates the short-run and long-run dynamics of the financial cycle in South Africa, focusing on its macroeconomic drivers and their asymmetric effects across different phases. It addresses the persistent challenge in emerging market economies of balancing financial development and stability amidst volatile conditions. Using monthly data from 2000 to 2024, the research employs a quantile autoregressive distributed lag (QARDL) model to capture the heterogeneity and persistence of macro-financial linkages across the financial cycle’s distribution. The use of the QARDL model in this study allows for capturing asymmetric and quantile-specific relationships that traditional linear models might overlook. Findings reveal that monetary policy, and the housing sector are key drivers of long-term financial development in South Africa, showing positive effects. Conversely, exchange rate movements, inflation, money supply, and macroprudential policy dampen financial development. Short-term financial booms are associated with GDP growth, credit, share, and housing prices. Money supply and inflation are more closely linked to burst phases. These results underscore the importance of policy coordination, particularly between monetary and macroprudential authorities, to balance promoting financial development and ensuring stability in emerging markets. This study contributes to the empirical literature and offers practical insights for policymakers. Full article

Improving the anaerobic digestion (AD) of swine manure is crucial for sustainable waste-to-energy systems, given its high organic load and process instability risks. This study examined the combined effects of substrate-to-inoculum ratio (SIR, 0.1–3.2) and magnetite-mediated direct interspecies electron transfer on biogas production, effluent quality, and microbial community dynamics. The highest methane yield (262 ± 10 mL CH₄/g COD) was obtained at SIR 0.1, while efficiency declined at higher SIRs due to acid and ammonia accumulation. Magnetite supplementation significantly improved methane yield (up to a 54.1% increase at SIR 0.2) and reduced the lag phase, particularly under moderate SIRs. Effluent characterization revealed that low SIRs induced elevated soluble COD (SCOD) levels, attributed to microbial autolysis and extracellular polymeric substance release. Furthermore, magnetite addition mitigated SCOD accumulation and shifted molecular weight distributions toward higher fractions (>15 kDa), indicating enhanced microbial activity and structural polymer formation. Microbial analysis revealed that magnetite-enriched Syntrophobacterium and Methanothrix promoted syntrophic cooperation and acetoclastic methanogenesis. Diversity indices and PCoA further showed that both SIR and magnetite significantly shaped microbial structure and function. Overall, an optimal SIR range of 0.2–0.4 under magnetite addition provided a balanced strategy for enhancing methane recovery, effluent quality, and microbial stability in swine manure AD. Full article

Recent progress in computer vision and embedded systems has facilitated real-time monitoring of bioprocesses; however, lightweight and scalable solutions for resource-constrained settings remain limited. This work presents a modular framework for monitoring Chlorella vulgaris growth by integrating RGB image processing with multimodal sensor fusion. The system incorporates a Logitech C920 camera and low-cost pH and temperature sensors within a compact photobioreactor. It extracts RGB channel statistics, luminance, and environmental data to generate a 10-dimensional feature vector. A feedforward artificial neural network (ANN) with ReLU activations, dropout layers, and SMOTE-based data balancing was trained to classify growth phases: lag, exponential, and stationary. The optimized model, quantized to 8 bits, was deployed on an ESP32 microcontroller, achieving 98.62% accuracy with 4.8 ms inference time and a 13.48 kB memory footprint. Robustness analysis confirmed tolerance to geometric transformations, though variable lighting reduced performance. Principal component analysis (PCA) retained 95% variance, supporting the discriminative power of the features. The proposed system outperformed previous vision-only methods, demonstrating the advantages of multimodal fusion for early detection. Limitations include sensitivity to lighting and validation limited to a single species. Future directions include incorporating active lighting control and extending the model to multi-species classification for broader applicability. Full article

This paper proposes an optimal-sliding-mode-based adaptive dynamic programming (ADP) master–slave synchronous control strategy for the actuator saturation and performance constraints that AUVs face in dynamic recovery. First, by introducing the sliding-mode function into the value function to optimize the state error and its derivative simultaneously, the convergence speed is significantly improved. Second, by designing the performance constraint function to directly map the sliding-mode function, the evolution trajectory of the sliding-mode function is constrained, ensuring the steady-state and transient characteristics. In addition, the hyperbolic tangent function (tanh) is introduced into the value function to project the control inputs into an unconstrained policy domain, thereby eliminating the phase lag inherent in conventional saturation compensation schemes. Finally, the requirement for initial stability is relaxed by constructing a single-critic network to approximate the optimal control policy. The simulation results show that the proposed method has significant advantages in terms of the position and attitude synchronization error convergence rate, steady-state accuracy, and control signal continuity compared with the conventional ADP method. Full article

Inflation is an indicator that signals emerging crises. The period of 2001–2024 witnessed numerous crises. Energy crises affect countries to varying degrees, making it important to identify those most sensitive to inflationary changes in energy prices. This study aims to assess the similarity in the dynamics of the annual inflation rates for the electricity, gas, and other fuels category (HICP—COICOP group 04.5) across Europe. In particular, we identify sub-periods and countries in which inflation indicators either led price changes in Poland or followed the inflation dynamics observed in Poland. This assessment of leading and lagging inflation dynamics is conducted using wavelet analysis, specifically analysis of the wavelet coherence with a phase difference, for Poland and 27 European countries. The analysis addresses two main questions. First, was there statistically significant coherence (correlation in the frequency domain over specific sub-periods) in energy price inflation processes between Poland and other countries? Second, which countries exhibited energy price inflation dynamics that led or lagged behind the pattern in Poland? For many countries, coherence with Poland was not significant in regard to short-term fluctuations (2–6 months) but became significant over longer time scales. Furthermore, at longer periodicities, Poland’s energy inflation dynamics were synchronous with those of many European countries, especially during the period of Russian aggression against Ukraine. This analysis identifies statistically significant coherence between Poland and the chosen European countries. Germany and Lithuania frequently led Polish energy price inflation, whereas other countries, such as Bulgaria and Spain, often lagged behind. These results reveal dynamic patterns in the time–frequency co-movements of energy inflation across Europe. Full article

The evolution of traditional rural settlements is a dynamic process. During urbanization, traditional rural settlements, as dual carriers of natural and cultural heritage, face the structural contradiction between preservation and development. The 2008 Wenchuan earthquake caused systemic damage to the Linpan settlements in western Sichuan. The post-seismic reconstruction (2008-) and rural revitalization (2017-) phases have offered a unique case for exploring sustainable cultural landscape patterns. This study innovatively devises a “preservation–development” dual-system evaluation framework. Using the coupling coordination degree model, it analyzes the characteristics of Linpan at different stages within a composite cultural–economic–social system. The study found that while tangible carriers can be quickly repaired through financial support, intangible culture is often at risk of losing its inheritors. Over 60% of Linpan depend on government support, exposing the fragility of “dependence-based development”, and few achieve high-quality “preservation–development” synergy (coupling coordination degree D > 0.8). Most remain in a “preservation lag–development obstruction” cycle (D < 0.5). This paper explores ways to balance Linpan preservation and development dynamically and suggests creating a self-cycling “resource empowerment–cultural identity–value transformation” development pattern. It provides a theoretical reference for cultural heritage preservation and disaster resilience building and contributes a unique solution for the revitalization of traditional settlements. Full article

In this study, we consider a fractional-order extension of the Jeffreys equation (also known as the dual-phase-lag equation) by introducing the Reimann–Liouville fractional integral, of order $0<\nu <1$, to the Jeffreys constitutive law, where for $\nu =1$ it corresponds to the conventional Jeffreys equation. The kinetical behaviors of the fractional equation such as non-negativity of the propagator, mean-squared displacement, and the temporal amplitude are investigated. The fractional Langevin equation, or the fractional damped oscillator, is a special case of the considered integrodifferential equation governing the temporal amplitude. When $\nu =0$ and $\nu =1$, the fractional differential equation governing the temporal amplitude has the mathematical structure of the classical linear damped oscillator with different coefficients. The existence of a real solution for the new temporal amplitude is proven by deriving this solution using the complex integration method. Two forms of conditional closed-form solutions for the temporal amplitude are derived in terms of the Mittag–Leffler function. It is found that the proposed generalized fractional damped oscillator equation results in underdamped oscillations in the case of $0<\nu <1$, under certain constraints derived from the non-fractional case. Although the nonfractional case has the form of classical linear damped oscillator, it is not necessary for its solution to have the three common types of oscillations (overdamped, underdamped, and critical damped), unless a certain condition is met on the coefficients. The obtained results could be helpful for analyzing thermal wave behavior in fractals, heterogeneous materials, or porous media since the fractional-order derivatives are related to the porosity of media. Full article

Background: Non-communicable diseases (NCDs) have become a major threat to global public health, with the disease burden particularly severe in developing countries, China being one of them. The preventive and control effects of traditional treatment methods on NCDs are limited, and innovative strategies are urgently needed. In recent years, vaccine technology has expanded from the field of infectious diseases to non-communicable diseases (NCDs). Therapeutic vaccines have shown the potential to intervene in chronic diseases through immunomodulation, but their research and development (R & D), as well as promotion, still face multiple challenges. Methods: This article systematically reviews the current development status of NCD vaccines worldwide and points out the imbalance in their matching with disease burden: current research focuses on the field of cancer, while there is a lack of targeted vaccines for high-burden diseases such as hypertension and chronic kidney disease; the progress of independent R & D in China lags behind, and there are implementation obstacles such as uneven distribution of medical resources between urban and rural areas and low public willingness to be vaccinated. Results: By analyzing the biological mechanisms of NCD vaccines and non-biological challenges, phased solutions are proposed: In the short term, focus on target discovery and improvement of vaccine accessibility. In the medium term, strengthen multi-center clinical trials and international technology sharing. In the long term, build a digital health monitoring system and a public–private partnership financing model. Conclusions: The breakthrough of NCD vaccines requires interdisciplinary collaboration and systematic policy support. Their successful application will reshape the paradigm of chronic disease prevention and control, providing a new path for global health equity. Full article

This paper addresses stability issues in modern power grids arising from extensive integration of power electronic converters, which introduce complex multi-time-scale interactions. A symbolic simplification method is proposed to accurately model grid-connected converter dynamics, significantly reducing computational complexity through transfer function approximations and yielding efficient reduced-order models. An impedance-based approach utilizing impedance ratio (IR) is developed for stability assessment under active-reactive (PQ) and active power-AC voltage (PV) control strategies. The impacts of Phase-Locked Loop (PLL) and proportional-integral (PI) controllers on system stability are analysed, with a particular focus on quantifying remote converter interactions and delineating stability boundaries across varying network strengths and configurations. Furthermore, time-scale separation effectively simplifies Multi-Voltage Source Converter (MVSC) systems by minimizing inner-loop dynamics. Validation is conducted through frequency response evaluations, IR characterizations, and eigenvalue analyses, demonstrating enhanced accuracy, particularly with the application of lead–lag compensators within the critical 50–250 Hz frequency band. Time-domain simulations further illustrate the adaptability of the proposed models and reduction methodology, providing an effective and computationally efficient tool for stability assessment in converter-dominated power networks. Full article

Understanding precipitation variability is essential for assessing climate dynamics and their impacts on agriculture, water resources, and infrastructure. This study analyzes subseasonal precipitation patterns in Rio Grande do Sul, Brazil, using 45-day accumulated intervals over a 17-year period (2006–2022), a timescale critical for understanding drivers of extreme events like the catastrophic floods of 2024. A total of 138 precipitation fields were generated from 670 spatial points. Spatial analysis revealed median precipitation values ranging from 130 to 329 mm/45 days, with the northeast showing the highest accumulations and the southwest showing the driest conditions. Temporal variability was marked by abrupt anomalies, with median peaks up to 462 mm and minima of 33 mm. Significant temporal autocorrelation (lag-1, 45 days) was identified in the central and northern regions, while lag-2 (90 days) showed inverse patterns in the south (correlation coefficient ≈ −0.45). Principal component analysis (KMO = 0.909; Bartlett’s χ² = 187,990.945; p < 0.05) identified seven dominant modes, with PC1 explaining 26% of total variance and highlighting extremely wet anomalies (e.g., SPI > 2.0). Correlation with the Oceanic Niño Index revealed heterogeneous responses to ENSO phases, with strong El Niño episodes (2009, 2015–2016) associated with precipitation peaks up to 966 mm/45 days. These results underscore the importance of subseasonal scales for understanding climate anomalies and support the development of regional forecast strategies and water management policies under increasing climate variability. Full article

Climate change poses significant challenges for viticulture, particularly in regions known for producing high-quality wines. Wine quality results from a complex interaction between climatic factors, regional characteristics, and viticultural practices. Methods: This study integrates statistical analysis, machine learning (ML) algorithms, and systems thinking to assess the extent to which wine quality can be predicted using monthly weather data and regional classification. The dataset includes average wine scores, monthly temperatures and precipitation, and categorical region data for Slovenia between 2011 and 2021. Predictive models tested include Random Forest, Support Vector Machine, Decision Tree, and linear regression. In addition, Causal Loop Diagrams (CLDs) were constructed to explore feedback mechanisms and systemic dynamics. Results: The Random Forest model showed the highest prediction accuracy (R² = 0.779). Regional classification emerged as the most influential variable, followed by temperatures in September and April. Precipitation did not have a statistically significant effect on wine ratings. CLD models revealed time delays in the effects of adaptation measures and highlighted the role of perceptual lags in growers’ responses to climate signals. Conclusions: The combined use of ML, statistical methods, and CLDs enhances understanding of how climate variability influences wine quality. This integrated approach offers practical insights for winegrowers, policymakers, and regional planners aiming to develop climate-resilient viticultural strategies. Future research should include phenological phase modeling and dynamic simulation to further improve predictive accuracy and system-level understanding. Full article

Lipoxygenases (LOXs) are a family of metalloenzymes that oxidize polyunsaturated fatty acids producing cell-signaling hydroperoxides. Fungal LOXs have drawn interest because of their roles in plant and animal pathogenesis. A new subfamily of annotated fungal LOXs has been predicted. One of its unique structural features is the presence of a cysteine amino acid encoded at the invariant leucine clamp. Herein, we isolate three representatives of this LOX subfamily from recombinant expressions in both yeast and bacterial cultures. Metal analysis indicates that the proteins accommodate a mononuclear manganese ion center, similar to other eukaryotic LOXs, but have nominal LOX activity. The functional consequence of the non-conservative mutation is further explored using a Leu-to-Cys (L546C) variant of soybean lipoxygenase, a model plant orthologue. While this L546C variant has comparable structural integrity and metal content to the native enzyme, the variant is associated with a 50-fold decrease in the first-order rate constant. The presence of cysteine at 546, compared to leucine, alanine, or serine, also results in a distinctive kinetic lag phase and product inhibition. The collective data highlight that Cys encoded at the Leu clamp is detrimental to LOX activity. Potential biological functions of these annotated fungal LOXs are discussed. Full article

Waste activated sludge (WAS), a byproduct of livestock wastewater treatment, poses significant disposal challenges due to its low biodegradability and potential environmental impact. Anaerobic digestion (AD) offers a sustainable approach for methane recovery and sludge stabilization. This study evaluates the biomethane potential (BMP) of WAS and its co-digestion with swine slurry (SS), water lily (Nymphaea spp.), and lotus (Nelumbo nucifera) shoot biomass to enhance methane yield. Batch BMP assays were conducted at substrate-to-inoculum (S/I) ratios of 1.0 and 0.5, with methane production kinetics analyzed using the modified Gompertz model. Mono-digestion of WAS yielded 259.35–460.88 NmL CH₄/g VS_added, while co-digestion with SS, water lily, and lotus increased yields by 14.89%, 10.97%, and 16.89%, respectively, surpassing 500 NmL CH₄/g VS_added. All co-digestion combinations exhibited synergistic effects (α > 1), enhancing methane production beyond individual substrate contributions. Lower S/I ratios improved methane yields and biodegradability, highlighting the role of inoculum availability. Co-digestion reduced the lag phase limitations of WAS and plant biomass, improving process efficiency. These findings demonstrate that co-digesting WAS with nutrient-rich co-substrates optimizes biogas production, supporting sustainable sludge management and renewable energy recovery in livestock wastewater treatment systems. Full article

The hydrogen/deuterium permeation behavior of X52MS pipeline steel with three thicknesses was investigated using the gas/liquid phase permeation method by changing the current density and regulating the surface roughness. The permeation curves under different conditions were obtained, the hydrogen/deuterium diffusion coefficients and related important parameters were calculated, and the surface morphology of the hydrogen-filled side was observed using scanning electron microscopy. It is found that the hydrogen diffusion coefficient and diffusion flux increase gradually with an increase in the hydrogen charging current density, while the hydrogen infiltration lag time gradually decreases. With the increase in surface roughness of the specimen, the corrosion degree of the surface after hydrogen penetration decreases, the hydrogen diffusion coefficient gradually decreases, and the penetration time, lag time, and hydrogen concentration on the cathode side gradually increase. Full article

The kinetics of insulin aggregation and fibril formation were studied in vitro using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. Our investigation centered on the protein’s morphological and structural changes to better understand the transient molecular configurations that occur during the lag phase. SEM images showed that, already at early incubation stages, a network of disordered pseudo-filaments, ranging in length between 200 and 500 nanometers, develops on the surface of large aggregates. At later stages, fibrils catalyzed by protein aggregates were observed. Principal Component Analysis (PCA) of the FTIR data identified signatures of intramolecular β-sheet secondary structures forming during the lag phase and at the onset of the exponential growth phase. These absorption bands are linked to secondary nucleation mechanisms due to their transient nature. This interpretation is further supported by a chemical equilibrium model, which yielded a reliable secondary nucleation rate constant, K₂, on the order of 10⁴ M⁻² s⁻¹. Full article