Search Results (8,983)

Objective: To analyze associations between 24-hour movement behaviors (and guideline adherence) and anthropometric and body composition indicators in Ecuadorian preschoolers using data from the International Study of Movement Behaviors in the Early Years (SUNRISE) pilot study. Methods: This secondary analysis utilized data from the primary study conducted in 108 children aged 3–4 years (57.4% girls; 50.9% urban). Anthropometry (weight, height, and body mass index [BMI]) was assessed using standardized protocols during the pilot study, whereas body composition indicators (fat-free mass [FFM], fat mass [FM], and body fat percentage) were estimated using a validated anthropometric prediction equation. Movement behaviors were assessed via triaxial accelerometry (ActiGraph GT3X+ or GT3X-BT, Pensacola, FL, USA) over seven days, complemented by parent-reported questionnaires. Exploratory unadjusted correlation analyses were performed using Spearman’s rho (ρ) for continuous/ordinal variables, and Pearson’s correlations (r), mathematically equivalent to point-biserial correlations (r_pb), for dichotomous–continuous associations. Results: In exploratory unadjusted analyses, device-measured longer sleep duration showed small-to-moderate inverse associations with weight (ρ = −0.33, p = 0.001), BMI (ρ = −0.28, p = 0.006), and FFM (ρ = −0.37, p < 0.001). Higher moderate-to-vigorous physical activity showed moderate positive associations with height (ρ = 0.32, p = 0.002), weight (ρ = 0.40, p < 0.001), and FFM (ρ = 0.44, p < 0.001). In complementary multivariable models, the associations between device-measured sleep or moderate-to-vigorous physical activity (MVPA) and the pre-specified anthropometric and body composition outcomes were attenuated after adjustment for age, sex, area of residence, and, where applicable, height, and were generally not statistically significant. Conclusions: In this exploratory secondary analysis of the SUNRISE Pilot Study Ecuador, unadjusted analyses identified associations between specific 24-hour movement behaviors, particularly sleep duration and MVPA, and anthropometric and body composition indicators. However, these associations were attenuated after covariate adjustment. The findings should therefore be interpreted as hypothesis-generating and require confirmation in larger longitudinal studies. Full article

Electrochemical parameter identification is crucial for evaluating the electrochemical processes in proton exchange membrane water electrolysis (PEMWE). Conventional characterization techniques-including polarization-curve fitting, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and current interruption (CI)-face significant limitations for rapid diagnostics under high-current dynamic operation, arising from constraints in instrument current rating, measurement time, zero-current control, and noise amplification in numerical differentiation. In this study, we present a simple current step (CS) method to accurately identify key electrochemical parameters and perform overpotential breakdown by using a simplified equivalent circuit model with a current source. To address the numerical instability in derivative calculation caused by sampling noise during voltage transient analysis, a physics-informed neural network (PINN) is introduced to enhance signal smoothness while guaranteeing physical consist ency. Compared with standard characterization, the proposed CS-PINN method demonstrates high accuracy, with an error of less than 2% in overpotential breakdown, less than 5.3% in ohmic resistance, and 2.8% in the Tafel slope (at 5 A/cm²). These results confirm that the CS-PINN method provides a fast, accurate, and equipment-friendly route for rapid electrochemical parameter identification in PEMWE. Full article

This study investigates the influence of rainfall variability on runoff generation in the Upper Ing River Basin and inflow to the Mae Tum Reservoir in northern Thailand using the physically based Soil and Water Assessment Tool (SWAT) version 2012. In small mountainous watersheds, water supply reliability for irrigation and domestic use—particularly for unmonitored royal initiated projects like the Mae Tum Reservoir—has become a critical concern due to shifting climatic extremes. A SWAT model was developed using detailed spatial data on topography, land use, and soil characteristics together with long-term daily climate and streamflow records. The model performance at Station I.17 was evaluated through calibration and validation using the R², Nash–Sutcliffe Efficiency (NSE), and percent bias indices. Rainfall regimes were classified into dry, normal, and wet years based on the mean and standard deviation of 25-year gauge records to drive scenario simulations. The calibrated model reproduced seasonal runoff patterns satisfactorily (monthly NSE up to 0.685 and R² up to 0.712). The simulations demonstrated the strong sensitivity of both the runoff at Station I.17 and reservoir inflow to interannual rainfall differences, with the annual runoff ranging from 71.5 to 379.7 million m³ and the annual inflow to Mae Tum Reservoir ranging from 28.84 to 48.33 million m³. These findings demonstrate that physically based spatial modeling can effectively replace traditional empirical operating rules, providing a highly transferable framework for runoff forecasting, reservoir inflow assessment, and climate responsive water resources planning in data-scarce tropical mountainous basins. Full article

Smartphone GNSS metadata remains an underexplored source for evaluating navigation-signal integrity in real-world conditions. We investigated GPS behavior recorded by a Samsung Galaxy A72 smartphone across two European flights (EXP03: Rome–Bucharest, n = 377; EXP10: Bucharest–Lisbon, n = 78) and 275 terrestrial reference photographs (Cabo da Roca, Portugal). A total of 730 photographs were analyzed using a seven-indicator taxonomy, conceptually inspired by Receiver Autonomous Integrity Monitoring (RAIM) principles, covering anti-spoofing, anti-sniffing, and anti-tampering checks. GPS capture rates reached 100% (Timestamp Camera) and 83.3% (native camera) up to 11,439 m WGS84, among the highest EXIF altitude profiles reported to date. Velocity spikes (1560–1875 km/h), one at cruise altitude and one during landing, were indistinguishable from GPS spoofing at the EXIF level, and their physical origin is undetermined. Phantom geolocation was absent in flight (0/442) versus 37.3% on the ground, consistent with GPS constellation visibility as the primary factor. In total, 88% (n = 920) of JPEG files lacked the standard EOI marker, generating false positives in integrity validators. Findings are device-specific, derived from non-independent observations, and require replication before generalizing to other GNSS receivers or latitudes. The framework offers a methodological basis for EXIF integrity analysis relevant to EU AI Act Article 10(3) data quality and UAV precision-agriculture georeferencing. Full article

Sudden tailings dam breaches trigger large-scale heavy metal compound pollution in coupled surface water–groundwater systems, requiring systematic full-cycle ecological damage quantification tools applicable to diverse contamination types. This study constructs an integrated full-cycle ecological damage assessment framework for sudden water pollution accidents, integrating three core modules: multi-model pollutant migration prediction, multi-scale aquatic biological damage diagnosis, and three-dimensional ecological-economic loss accounting. The framework adopts a modular design that can potentially accommodate heavy metals (Cd, Cr, As, Pb) and organic pollutants such as polycyclic aromatic hydrocarbons (PAHs), with standardized molecular, individual, and population-level biological endpoints and corresponding pollutant dose–response templates reserved as reference calculation modules. However, applicability beyond this case has not been validated and requires case-specific calibration. To verify the operability and accuracy of the proposed integrated system, a typical tailings dam leakage incident dominated by hexavalent chromium (Cr(VI)) and arsenic (As) pollution was selected as the practical validation case; all field monitoring, pollutant simulation, and final economic loss quantification in this case exclusively rely on on-site measured Cr(VI) and As data, while Cd and PAH-related biological response curves and remediation cost formulas retained in the manuscript only serve as illustrative universal template components of the framework rather than case-measured results. For the Cr(VI)/As pollution case, the advection–diffusion model simulation revealed that the Cr(VI) contamination plume horizontally spread 250 m within 48 h and extended to 560 m after seven days, and anaerobic groundwater environments drove the transformation of toxic mobile trivalent arsenic (As(III)) from primary pentavalent arsenic. The calibrated SWAT model achieved Nash–Sutcliffe efficiency (NSE) coefficients of 0.75 for dissolved Cr(VI) and 0.68 for particulate As. The graph theory-based rapid prediction model cut computation duration down to minutes; when validated against independent field monitoring data, it yielded an average relative error of 14.2%, and its consistency with the SWAT model reached 10.5% relative deviation, satisfying the accuracy requirement for emergency early warning. Field biological monitoring demonstrated substantial ecological impairment: metallothionein (MT) expression in fish tissues was markedly elevated (the reported 6.2-fold induction value derives from standard Cd exposure template tests within the framework, with analogous MT upregulation also observed for field Cr(VI)/As co-stress), and benthic community Shannon diversity declined by over 50% in polluted river reaches. The standardized Ecological Damage Index (EDI) of the case was calculated as 480.2, indicating severe aquatic ecosystem damage, with total comprehensive ecological and economic losses reaching 17.25 million CNY. This study innovatively couples high-precision physical transport models with fast emergency prediction algorithms and establishes a complete multi-tier biological indicator chain linking molecular biomarkers to community integrity metrics; the three-dimensional loss accounting system integrating ecosystem service impairment, restoration expenditure, and post-pollution recovery loss realizes closed-loop full-cycle damage evaluation. The proposed framework, demonstrated for Cr(VI) and As pollution, has a modular design that may potentially be extended to other pollutants such as Cd and PAHs by adjusting model parameters, providing a quantitative reference for emergency disposal, pollution remediation, and ecological compensation of water contamination accidents, although further validation across different pollutants and hydrological settings is required. Full article

Referees and assistant referees play a central role in enforcing the Laws of the Game during matches. The main referee holds ultimate responsibility, while assistant referees monitor offside situations, signal fouls outside the referee’s line of sight, and assist with decisions on corner kicks, free kicks, and other restarts. Throughout the match, assistant referees use short flags to communicate standardized signals to the referee, making effective coordination essential for accurate match management. This study used a crossover design to examine the effect of flag use on repeated-sprint performance among 37 soccer assistant referees (19 Premier League and 18 National League) in Israel, assessed using a modified change-of-direction (CODA) protocol. The evaluated measures included total sprint time (TST), ideal time, percentage decrement in performance (PD), average heart rate, and subjective rating of perceived exertion (RPE). Statistical analysis revealed significant differences between conditions. Performance was better without the flag in both total sprint time (p < 0.05, d = 0.55) and ideal time (p < 0.05, d = 0.62). The percentage decrement was higher in the no-flag condition (p < 0.05). Higher heart rate (p < 0.05, d = 1.49) and higher RPE (p < 0.01) were also recorded. These findings suggest that flag carriage may constrain sprint performance during repeated change-of-direction tasks and should be considered in the physical testing and preparation of soccer assistant referees. Full article

The increasing penetration of renewable energy has significantly intensified the demand for flexible operation of thermal power plants, making dynamic simulation an essential tool for understanding transient behaviors and developing advanced operational strategies for circulating fluidized bed (CFB) power plants. This review critically examines the existing dynamic modeling approaches for industrial-scale CFB power plants, with particular emphasis on their applicability to flexibility studies. Existing CFB flue-gas side models are systematically classified into three categories: 3D physics-based CFD models, behavioral/data-driven models, and semi-empirical mechanistic models. Their characteristics are critically compared in terms of spatial and temporal scales, empirical dependence, model generality, computational and implementation burden, and applicability to CFB flexibility studies. Dynamic modeling of the steam–water cycle is also reviewed, showing that it has reached a relatively mature stage owing to well-established thermo-hydraulic theories and standardized modeling platforms. The current research bottleneck is therefore identified as the dynamic coupling between the flue-gas side and the steam–water cycle for integrated CFB whole-plant simulation. Based on the comparative analysis, semi-empirical mechanistic models are identified as a particularly suitable framework for industrial-scale CFB flexibility studies requiring minute-to-hour transient simulation, physical interpretability, and whole-plant coupling. Finally, future research directions are discussed, highlighting how integrated dynamic models can support CFB flexibility-enhancement technologies and the development of new-generation coal-fired power plants. Full article

Repeated non-equidistant unmanned aerial vehicle (UAV) inspections of slope-road cracks require measurements from different distances, poses, and image scales to remain comparable and sufficiently precise for engineering-state decisions. Existing studies rarely integrate cross-view physical conversion, measurement uncertainty, and a project-defined minimum detectable change. We develop an engineering-detectability framework that defines cross-period criteria for crack width and displacement and derives equivalent widths for ideal, representative non-standard, and arbitrary viewpoints. First-order error propagation and reliability allocation convert the minimum detectable change into accuracy requirements for range, field of view, and normalized image coordinates. Crack-boundary coordinates and localization uncertainties provide a common interface for interchangeable detection and photogrammetric modules. Validation combines a controlled fixed-camera sequence with a close-range field-camera multiview test of seven physical openings under local coplanarity. All six determinate stages in the controlled sequence agreed with the digital image correlation (DIC) comparison, while one borderline stage required review. Across the seven openings, the four-view means gave a mean absolute error (MAE) of 0.196 mm and a root mean square error (RMSE) of 0.270 mm, with cross-view coefficients of variation (CVs) of 0.33–4.93%. An illustrative error budget demonstrates reverse screening of system configurations from project thresholds. The framework therefore connects viewpoint-equivalent measurements, uncertainty constraints, and engineering-state decisions in an auditable chain. Full article

Objective: To examine the reliability, construct validity, and discriminative capacity of the Spanish version of the Economic Living Standards Index Short Form (ELSI_SF) in a sample of older adults in Spain. Methods: This analysis was conducted using baseline data from 133 participants (mean age = 66.2 years, SD = 5.6; 53.8% women) recruited from community health and social centers in the provinces of Cuenca, Albacete, and Toledo within the PEPE cohort. Participants completed the ELSI_SF (25 items), sociodemographic measures, the SF-12 Health Survey, and the International Fitness Scale (IFIS). Internal consistency was assessed using Cronbach’s alpha. Convergent validity was examined through correlations between ELSI_SF scores and education, occupation, physical and mental health, and perceived fitness. Discriminative ability for health-related variables was analyzed using ANOVA and partial η². The internal structure was explored using exploratory factor analysis (EFA) and subsequently examined against the original four-factor theoretical model using confirmatory factor analysis (CFA), based on polychoric correlations and estimation methods appropriate for ordinal data. Results: The mean ELSI_SF score was 23.0 ± 3.9, with most participants classified as having comfortable or good living standards. Internal consistency was acceptable for the total scale (α = 0.779), whereas the ownership restrictions (α = 0.441) and self-rating (α = 0.319) subscales showed low reliability. Significant associations were observed between the ELSI_SF total score and selected socioeconomic and health-related measures. Factor-analytic findings provided only partial support for the original four-domain structure. Although CFA showed favorable CFI, TLI, and RMSEA values, the elevated SRMR and instability of the self-rating factor warrant cautious interpretation of the factorial solution. Conclusions: The Spanish ELSI_SF provides preliminary psychometric evidence supporting the use of its total score among relatively socioeconomically advantaged older adults. However, limitations in subscale reliability, factorial stability, and the restricted socioeconomic variability of the sample preclude definitive validation across the full spectrum of material living standards. Further evaluation in larger, independent, and more socioeconomically heterogeneous samples, particularly including older adults experiencing material deprivation, is required. Full article

Physics-informed neural networks (PINNs) approximate partial differential equations (PDEs) by enforcing governing equations and boundary conditions during training, but their accuracy depends on how collocation points are distributed and updated. We propose spatiotemporal compositional active sampling (STCAS), a reference-assisted offline configuration procedure that uses an analytic or high-accuracy numerical solution to rank complete three-stage sampling plans. It screens eight fixed rules, forms a task-specific shortlist, and evaluates bounded fixed, switched, and locally blended plans with independent selection sets and a composition guard. A safety-anchor decision retains the standard PINN unless the selected candidate is at least 5% better. Across five evaluations on 18 analytically specified two-dimensional Poisson tasks, this protocol improves 16 task means and ties two, reducing aggregate relative-$L_2$ error by 12.8% (hierarchical-bootstrap 95% interval $[6.78\%,19.32\%]$; one-sided paired Wilcoxon $p=2.19\times {10}^{-4}$). Against the confirmed fixed plan, aggregate error decreases by 8.2%. In comparison experiments designed for two transfer tasks and matched for main PINN training budgets, STCAS achieves the lowest aggregate mean reported error among the compared methods for both a steady convection–diffusion equation and a nonlinear time-dependent Burgers equation; its offline search cost is additional. Full article

Time-of-flight magnetic resonance angiography (TOF-MRA) is widely used for noninvasive visualization of arterial anatomy, but extracting hemodynamics like blood velocity typically requires supplementary phase-contrast scans, tagging or multi-TE images. This study proposes a novel, physics-informed computational framework to extract variable fluid velocity directly from standard TOF-MRA signal profiles. We analytically expand the approach-to-steady-state Bloch equations to include convective flow, establishing a mathematical relationship between the spatial decay of longitudinal magnetization and fluid velocity. The velocity derivation was further extended to pointwise estimation over a 1-D centerline, overcoming the limitations of constant-velocity assumptions. To validate and solve this problem, a MATLAB (R2025b) simulation framework was developed to model fluid flow in two variable-geometry flowing tube cases, i.e., continuous narrowing and focal stenosis, under synthetic scanner noise. A global inverse optimization approach utilizing Dual-Tikhonov regularization was applied to stably invert the ill-posed transit time integral, actively penalizing high-frequency numerical ringing while preserving structural curves. The computational simulations successfully recovered ground-truth point-wise velocities, tracking gradual hemodynamic accelerations and sharp stenotic jets. This theoretical framework and the example centerline TOF-MRA signal intensity provide a robust mathematical proof-of-concept that quantitative, localized functional hemodynamic metrics can be extracted from standard structural MRA imaging, establishing a foundation for advanced flow quantification without requiring additional scan time. Full article

In recent years, hydrogen-fueled internal combustion engines offer significant potential for achieving high efficiency and near-zero carbon emissions. However, stable combustion remains challenging due to the limited time available for fuel–air mixing, particularly in direct-injection concepts. This study investigates the influence of injector orientation on in-cylinder charge preparation in a heavy-duty spark-ignition engine operating with a side-mounted hydrogen direct-injection strategy. Three-dimensional computational fluid dynamics (CFD) simulations are performed to evaluate the effects of injector blow-cap inclination and azimuthal alignment on hydrogen jet evolution, flow-field development, and mixture formation. Under high-pressure injection conditions, hydrogen enters the cylinder as a highly under-expanded jet with strong momentum, resulting in significant interaction with the in-cylinder flow field. The results show that injector inclination influences jet impingement behavior, wall-guided flow development, and subsequent vortex evolution, while injector rotation modifies the interaction between the jet trajectory and in-cylinder swirl motion, affecting aerodynamic shear and flow-field complexity. The resulting mixture formation is evaluated through local air–fuel ratio distribution together with flow-field analysis and streamline evolution, demonstrating strong sensitivity to injector orientation and its coupling with in-cylinder aerodynamic structures. Quantitatively, injector orientation produces significant changes in the local air–fuel ratio distribution, with up to 25% reduction in the standard deviation of local air–fuel ratio for inclination variations and up to 35% for azimuthal variations between the extreme configurations, indicating improved mixture uniformity. Configurations promoting earlier jet disruption and enhanced spatial dispersion achieve more homogeneous charge preparation, whereas stronger wall-guided jet attachment results in localized fuel-rich regions. The findings provide physical insight into the role of jet–wall interaction, aerodynamic shear, and vortex restructuring in governing hydrogen mixing processes. The simulation framework captures the relevant in-cylinder flow physics and provides trends consistent with available experimental observations in the literature, which report improved efficiency and reduced NOx emissions under enhanced mixture homogeneity conditions. Full article

Accurate crack width measurement is essential for the condition assessment of reinforced concrete (RC) bridges, yet most unmanned aerial vehicle (UAV) inspections remain limited to pixel-level observations that cannot be converted into reliable metric units without an external scale reference. This paper presents a lightweight, drone-agnostic UAV-mounted metrology system that enables standards-aligned metric crack width measurement directly from inspection imagery. The payload integrates a focusable diffractive optical element (DOE) red laser that projects a cross pattern of known angular geometry, three TF-Luna time-of-flight (ToF) distance sensors, and an ESP-WROOM-32 microcontroller that provides dual-rate sampling, Bluetooth Low Energy (BLE) streaming, and on-board logging. A two-stage calibration links the synchronized distance measurements to the physical length of the projected cross, yielding an image-specific pixel-to-millimeter scale that is applied to pixel-level crack widths obtained from a vision-based segmentation pipeline. The system is field-deployed on the Puente Huamani Bridge in Pisco, Peru, where measurements of 39 cracks classified under AASHTO MBEI condition states are compared against independent manual measurements by six inspectors. The proposed system reduces measurement variability across all condition states (CS), lowering the average coefficient of variation from 0.36 to 0.10 for fine CS1 cracks, from 0.27 to 0.11 for CS2, and from 0.22 to 0.07 for CS3. Cross-platform adaptability is demonstrated through an additional deployment on a DJI Matrice 350 RTK at the Low Level Bridge in Edmonton, Canada. The results indicate that the system provides a practical, low-cost, and scalable solution for repeatable, standards-aligned UAV-based bridge crack assessment. Full article

The dipole antenna is one of the oldest and most widely used devices in electromagnetic engineering, yet the behavior of its near-field during emission remains only partially captured by classical models. In the source-free region surrounding the arms, the vacuum Maxwell–Heaviside equations provide an insufficient number of configurations to describe the transient through which a bound signal becomes a freely propagating wave. We revisit the model equations, introducing an extended formulation in which an auxiliary velocity field complements the electromagnetic fields. Similarly to plasma physics, the outgoing signal is treated as an electromagnetic fluid carrying a charge density. As the far field is concerned, the resulting system admits an exact family of spherical free-wave solutions that follow the rules of geometrical optics. The near-to-far field transition also acquires a concrete dynamical description, thanks to the introduction of the pseudocharge, which is a charge-like density identified with the divergence of the electric field. In addition, a pressure-like potential, vanishing in the far field, tracks the conversion between bound and radiating energy. The approach is illustrated on a standard dipole antenna through direct numerical simulation of the full coupled system. The results suggest a unified analytical and computational pathway for antenna modeling, with natural extensions to more complex geometries and other radiating devices. Full article

N-acetylcysteine (NAC) is a thiol-containing molecule with antioxidant, anti-inflammatory, antimicrobial, and cytoprotective properties that has increasingly been incorporated into hydrogel-based biomaterials. This systematic review evaluates the strategies used to integrate NAC into hydrogels and examines their effects on material properties, controlled release, biocompatibility, and therapeutic activity. The review was conducted according to the PRISMA guidelines using Scopus, PubMed, Web of Science, and SciFinder to identify English-language articles published between 2000 and 2025. Seventy-three studies met the eligibility criteria of this review. NAC has been employed as a physically loaded therapeutic agent, covalently conjugated polymer modifier, contributor to hydrogel crosslinking, metal-coordination ligand, and compound incorporated into nano- and microparticulate carriers dispersed in hydrogel. These approaches enable the modulation of gelation, swelling, adhesion, degradation, and drug-release kinetics. NAC-containing hydrogels have demonstrated robust antioxidant, antimicrobial, antibiofilm, anti-inflammatory, angiogenic, and tissue-regenerative properties in various in vitro and in vivo models, underscoring their potential for advanced biomaterial applications. Release profiles varied from rapid stimulus-responsive delivery to sustained release over several days, depending on the network architecture and the NAC–matrix interactions. However, comparisons among studies were limited by the heterogeneous formulations, release conditions, biological models, and outcome measures. Standardized physicochemical characterization, NAC stability assessment, dose–response evaluation, and rigorous preclinical validation are required to support the translation of NAC-based hydrogels into biomedical applications. We hope that this review will help scientists and innovation centers understand the potential of the NAC-containing hydrogel biomaterials discussed in this study, as well as the opportunities and demands for additional research in this field. Full article