Search Results (180)

The anisotropic properties of wood make timber beams prone to developing longitudinal cracks. Notably, cracks occurring at the mid-height position are both highly common and critically detrimental to structural load-bearing capacity. This study focuses on the influence mechanisms of such cracks through four-point bending tests on 860 specimens, finite element simulations, and fracture morphology analyses. By introducing a horizontal crack location parameter called crack eccentricity (e), the influence of cracks at different horizontal positions on timber beam load-bearing capacity was investigated. The experimental results show that the horizontal position of the crack has a “critical eccentricity effect”: when e is below the critical value, cracks will not propagate and will have a minor impact on the load-bearing performance of timber beams; when e exceeds the critical value, cracks will propagate and their harmfulness will increase dramatically. As a special case, specimens with side-opening cracks (e = 1) exhibit “damage saturation” characteristics. That is, when the crack length exceeds the threshold (half of the beam span), regardless of further lengthening, the bearing capacity is unchanged and the damage evolution reaches a saturation plateau. The above analysis results suggest that the influence of cracks on the bearing capacity of timber beams may be counterintuitive. The calculation method for the “crack hazard coefficient” proposed in this study can provide a reference for crack hazard assessments. Full article

Background/Objectives: Inclusive nutrition services and data on children with disabilities living in low- and middle-income countries remain limited. We estimated the prevalence of undernutrition and described feeding practices and difficulties among children with disabilities ages birth to 10 years at a rehabilitation hospital in Uganda and identified barriers and opportunities for inclusive nutrition. Methods: This cross-sectional study enrolled 428 children. Data included demographics, weight, height, mid–upper arm circumference (MUAC), hemoglobin levels, risk for feeding difficulties, caregiver-reported feeding practices, and functional difficulties complemented by 32 caregiver and stakeholder interviews. Undernutrition was defined using WHO z-scores, MUAC, and anemia cutoffs. Associations were examined using Pearson’s chi-squared tests and adjusted odds ratios from logistic regression. Results: Over half of participants were boys (56.1%) and 65.9% were <24 months old. Common conditions included cleft lip/palate (55.4%) and cerebral palsy (38.6%). Undernutrition was prevalent: 45.2% were underweight, 38.3% stunted, 16.1% wasted (by MUAC), and 39.5% anemic. Being at risk for feeding difficulties (67.2% of children) increased the odds of underweight [AOR = 2.28 (1.23–4.24)], stunting [2.46 (1.26–4.79)], and wasting [2.43 (1.10–5.35)] after adjusting for covariates. Bottle-feeding increased the odds of stunting [3.09 (1.24–7.70)] in infants with cleft lip/palate < 12 months old. Poor access to services, food insecurity, and feeding challenges were key barriers to optimal nutrition. Most caregivers reported using practices that support responsive feeding. Conclusions: Reported barriers to services and high levels of undernutrition, strongly linked to feeding difficulties, underscore the need for targeted feeding interventions and better access to inclusive nutrition services in Uganda. Full article

Background/Objectives: Feeding difficulties are more common in children with autism spectrum disorder (ASD) or other developmental conditions and are associated with nutritional risk and caregiver stress. However, they may be overlooked as growth tends to be preserved. We aimed to identify clinical and behavioral features associated with feeding difficulties among children with developmental conditions. Methods: This cross-sectional study included caregiver–child dyads, with children aged 1–7 years with ASD and other developmental conditions. Caregivers completed the Repetitive Behavior Questionnaire, Second Edition (RBQ-2) to assess child restricted and repetitive behaviors (RRBs) and the Behavioral Pediatrics Feeding Assessment Scale (BPFAS) to assess feeding difficulties. Demographics, anthropometric measures and cognitive and adaptive scores were retrieved from medical records. Results: Of the 132 participants (mean age 41.8 months, range 15–67; 74.2% male) included, majority had normal weight (87.7%) and height (89.2%) z scores. Among participants, 54.5% had autism, 26.5% language delay and 18.9% other developmental diagnoses. Over half (53.0%) had elevated BPFAS scores. Children not enrolled in school showed significantly more feeding difficulties compared to those who were enrolled (32.6% vs. 16.7%, p < 0.05). The RBQ-2 total score positively correlated with the BPFAS total frequency score (r = 0.33, p = 0.01) after adjusting for gender, age and developmental diagnosis. Conclusions: Feeding difficulties were common in this sample. Higher RRBs and absence of formal schooling were associated with higher rates of feeding difficulties. Longitudinal studies are needed to ascertain the role of RRBs and school enrollment as clinical indicators associated with feeding difficulties. Full article

Background/Objectives: Advanced Practice Nurses (APNs) counsel patients regarding diet and exercise behaviors and serve as role models for health promotion and prevention of chronic disease. This study evaluated personal diet and exercise behaviors of APNs and their association with body mass index (BMI) as a biomarker of obesity and disease risk. Methods: APNs (N = 1268) self-reported height and weight, and answered four questions regarding personal diet and exercise. Based on BMI, they were grouped as normal weight (≤24.9 kg/m²) and overweight/obese (≥25.0 kg/m²). Results: The prevalence of overweight/obesity was 55%. The majority of APNs engaged in muscle strengthening exercises (53%) and consumed fruits and vegetables (62%), and protein foods and/or supplements (94%), while less than half engaged in moderate–vigorous physical activity (46%). Exercise behaviors (moderate–vigorous physical activity and muscle strengthening exercises) had a statistically significant impact on BMI. The predicted decrease in BMI due to participation in moderate–vigorous physical activity was 2.06 kg/m² and the predicted decrease due to muscle strengthening exercises was 1.35 kg/m². Diet behaviors (consumption of fruit, vegetables, and protein) were not found to have a significant impact on BMI. Conclusions: The prevalence of overweight/obesity among APNs in the United States is less than what is reported for the general adult population. Exercise behaviors, especially moderate–vigorous physical activity, significantly impact BMI and are associated with clinically meaningful differences. By comparison, healthy diet behaviors, including consumption of fruits, vegetables, and protein, are relatively widespread among advanced practice nurses but do not appear to significantly impact BMI. Full article

An unmanned aerial vehicle (UAV) multi-spectral system provides a monitoring platform to rapidly obtain crop spectral information that can reflect crop nitrogen status for the generation of dynamic variable-rate nitrogen (VRN). To improve the accuracy of VRN prescription maps, a method of generating VRN prescription maps on the basis of the vegetation index was proposed, and the effects of UAV flight time and altitude on VRN prescription maps were analyzed. The experimental site was located in Dacaozhuang, Hebei Province, China, and the experimental crop was winter wheat (Lunxuan 145). The flight altitudes of the UAV system were set to 50, 70 and 90 m. The flight times were set to 8:00 a.m., 11:00 a.m., 2:00 p.m. and 5:00 p.m. local time. The flight area was 1.18 ha with a 60° rotation angle under a three-span center pivot irrigation system with an overhang. UAV flight missions were executed during the jointing, heading, and grain filling phases of winter wheat. There were 90 management zones with pie shapes in total, which were composed of a 10° angle in the rotation direction and 4 sprinklers along the lateral direction. The vegetation indices (VIs) which are closely related to crop nutrient status were selected and used to generate distribution maps, which were superimposed with the management zones to generate VRN prescription maps. The results demonstrated that the red-edge soil adjusted vegetation index (RESAVI) was relatively more sensitive to the nitrogen status of winter wheat than the other VIs were. The RESAVI distributions were stable during periods with a solar elevation angle greater than 50° (11:00 a.m.–2:00 p.m. local time), and the VRN prescription maps were similar, with the overlap percentage of the same fertilization grade being greater than 80% and the relative error of the fertilization amount being less than 5%. Compared with that at 2:00 p.m., the overlap percentage of the same fertilization grade was 56.6% in both seasons at 8:00 a.m., whereas flights at 5:00 p.m. exhibited overlaps of 70.9% and 44.6% in the 2023 and 2024 seasons, respectively. Conversely, the flight altitude had little influence on the fertilizer amount and VRN prescription maps. The difference in the amount of fertilizer used was less than 3% at different flight altitudes. The required time is half of that for a 50 m flight when the flight altitude is 70 m and one third of that when the flight altitude is 90 m. Our study recommended operating the UAV multi-spectral system at solar elevation angles greater than 50° when generating VRN prescription maps of winter wheat, and the flight height can be adjusted according to the field area and the endurance time of the UAV. Full article

Background and Objectives: Osteoporotic vertebral compression fractures (OVCFs) are a common cause of morbidity in the elderly, often resulting in pain, reduced mobility, and diminished quality of life. Treatment options include conservative management, vertebroplasty (VP), and kyphoplasty (KP). This study aimed to compare the clinical outcomes and complication rates of patients treated with kyphoplasty/vertebroplasty versus conservative methods and identify risk factors associated with the development of new fractures. Materials and Methods: This retrospective cohort study included patients diagnosed with OVCFs who were treated either surgically (KP/VP) or conservatively between January 2020 and January 2025. Inclusion criteria encompassed vertebral height loss on CT, STIR hyperintensity on MRI, and a T-score below −2.5. Patients were followed for at least one year. Clinical evaluations included pain scores (VAS), functional status (ODI), and quality of life assessments. Complications and new fracture rates were recorded. Logistic regression analysis was performed to identify risk factors influencing fracture recurrence. Results: A total of 132 patients were analyzed: 65 in the KP/VP group and 67 in the conservative treatment group. The KP/VP group achieved better postoperative pain results (3.2 ± 1.0 vs. 4.0 ± 1.2) with a significant difference of −0.8 (95% CI: −1.2 to −0.4, p = 0.032) and better mobility results (ODI: 4.5 ± 0.8 vs. 3.9 ± 0.9) with a significant difference of 0.6 (95% CI: 0.3–0.9, p = 0.047) and improved quality of life scores (6.7 ± 1.1 vs. 5.9 ± 1.3) with a significant difference of 0.8 (95% CI: 0.4–1.2, p = 0.041). The incidence of new fractures was similar between groups (15.4% vs. 17.9%, p = 0.678). Overall complication rates were 7.7% in the KP/VP group versus 11.9% in the conservative group (p = 0.435). The results from logistic regression analysis showed that age (adjusted OR: 2.48, 95% CI: 1.20–5.13), low bone mineral density (adjusted OR: 0.31, 95% CI: 0.15–0.63), and cement leakage (adjusted OR: 3.10, 95% CI: 1.21–7.99) were identified as risk factors for new fractures. The study found that outdoor activity (adjusted OR: 0.38, 95% CI: 0.20–0.73) and anti-osteoporosis treatment (adjusted OR: 0.17, 95% CI: 0.04–0.79) acted as protective factors against new fractures. The KP/VP group required half the time to recover from their injuries because they used their braces for 3.0 ± 0.5 months instead of 6.0 ± 1.0 months (p < 0.001). Conclusions: Kyphoplasty and vertebroplasty were more effective than conservative treatment in improving pain, mobility, and quality of life in patients with OVCFs. Although the incidence of new fractures did not differ significantly between groups, surgical treatment demonstrated lower complication rates and significantly faster recovery, as evidenced by reduced brace use duration. These findings support the use of KP/VP as a viable option for managing OVCFs in appropriately selected patients. Full article

Background: The study evaluated the acute effect of dryland maximum strength (MS) training on water polo performance. Methods: Twelve female players (20.3 ± 1.4 years) underwent initial assessments, including a head-out 20 m swim and a one-repetition maximum (1RM) strength test in three exercises: bench press, seated pull row, and half squat. These exercises were used as the experimental (EXP) condition. During the main testing sessions, participants completed the EXP and a control (CON) condition. In the EXP, players completed MS training (three sets of six repetitions at 80% 1RM), followed 15 min later by in-water testing. In the CON, only the in-water tests were performed. These included a 10 s tethered swim to measure force, a 20 m head-out swim at maximum intensity to measure performance time, ten goal-targeted throws to reach the highest accuracy and throwing velocity, and three in-water vertical jumps as high as possible. Results: The performance time in the head-out 20 m swim (EXP: 14.21 ± 0.4, CON: 14.18 ± 0.5 s), tethered swimming force (EXP: 86.85 ± 14.82, CON: 89.58 ± 15.92 N), shooting velocity (EXP: 14.67 ± 1.19, CON: 14.91 ± 0.32 m·s⁻¹), shooting accuracy (EXP: 16.5 ± 5.4, CON: 19.0 ± 5.1 points), and in-water vertical jump height (EXP: 51.7 ± 5.6, CON: 52.9 ± 4.2 cm) were no different between conditions (p > 0.05). Conclusions: Dryland maximum strength training performed with high loads (80% 1RM) does not impair subsequent performance during sport-specific testing in female water polo players. These findings suggest that such MS training can be safely implemented 15 min prior to in-water training sessions. Full article

Mixed cell heights pose significant challenges to placement in large-scale integrated circuits. In particular, the heterogeneity of cells remarkably complicates the legalization of mixed-cell-height cells. To preserve the global placement results as much as possible, we propose to directly optimize the total displacement through $l_1$-norm minimization. For illegal cells that extend beyond the chip boundaries, the netlist information of cells is taken into account and a mixed-integer programming model is employed to determine the optimal placement that minimizes the half-perimeter wirelength (HPWL) variation. This joint optimization strikes a balance between minimizing geometric displacement and HPWL, ensuring that the legalization process remains compact to achieve better placement performance. Experimental evaluations on mixed-cell-height benchmarks demonstrate that the proposed approach achieves smaller total displacement and notably lower HPWL variation within practical time limits compared with state-of-the-art legalization methods. Moreover, this work provides a scalable foundation for future extensions to three-dimensional (3D) IC placement legalization. Full article

Background: Change-of-direction (CoD) ability is critical in karate, yet sport-specific assessment tools are limited. This study aimed to evaluate the reliability and validity of a newly developed karate-specific CoD test for male and female athletes and to examine its relationships with other motor performance measures. Methods: Thirty-six experienced karatekas (20 men: age 20.8 ± 1.8 years, height 1.79 ± 0.05 m, body mass 73.1 ± 10.6 kg; 16 women: age 21.2 ± 1.7 years, height 1.67 ± 0.04 m, body mass 63.5 ± 8.9 kg), all national squad members, participated. Athletes performed the karate CoD test twice to assess test–retest reliability, and completed additional CoD tests (Y CoD, T-half), linear sprint tests, standing long jump, and Y-balance tests to evaluate criterion validity and associations with other motor abilities. Results: The karate CoD test demonstrated excellent reliability (ICC = 0.996), with similar consistency in men and women. Criterion validity was supported by a meaningful correlation with the Y CoD test, but not with the T-half test. Associations with linear sprinting and lower-limb power (standing long jump) were weak or inconsistent, indicating that karate-specific CoD performance is distinct from general physical capacities. Conclusions: The karate CoD test shows good reliability and validity for assessing planned change-of-direction ability in elite karate athletes. Its use should be limited to pre-planned movements and complemented with other tests (e.g., reactive agility, sprinting, jumping, strength) for a fuller performance assessment. Full article

Pure Loss of Stability is one of the five typical stability failure modes identified in the Second-Generation Intact Stability Criteria by the IMO. This study investigates the influence of hull line variations on the vulnerability of a saury fishing vessel to pure loss of stability. Hull forms were parametrically modified using the Free-Form Deformation method, and an in-house code was developed to evaluate stability performance. The numerical framework was validated against the commercial ICS-HydroSTAB software (Version 1.0), demonstrating high computational accuracy and engineering applicability. Parametric sensitivity analysis was then conducted to examine the effects of geometric characteristics under both calm-water and wave-induced conditions. The results indicate that vulnerability in calm water is primarily governed by the maximum sectional area curve and the bow portion of the DWL half-breadth curve, while in waves it is influenced by both the maximum sectional area curve and the fore and aft portions of the DWL half-breadth curve. The half angle of entrance (E = 0.08) exhibits a comparatively minor effect, but its increase reduces the initial metacentric height and significantly elevates the risk of capsizing in waves. These findings provide useful references for hull form optimization and stability design. Full article

Accurate estimation of the forest canopy height is crucial in monitoring the global carbon cycle and evaluating progress toward carbon neutrality goals. The Global Ecosystem Dynamics Investigation (GEDI) mission provides an important data source for canopy height estimation at a global scale. However, the non-zero half-width of the transmitted laser pulses (NHWTLP) and the influence of terrain slope can cause waveform broadening and overlap between canopy returns and ground returns in GEDI waveforms, thereby reducing the estimation accuracy. To address these limitations, we propose a canopy height retrieval method that combines the deconvolution of GEDI’s transmitted waveforms with terrain slope constraints on the ground response function. The method consists of two main components. The first is performing deconvolution on GEDI’s effective return waveforms using their corresponding transmitted waveforms to obtain the true ground response function within each GEDI footprint, thereby mitigating waveform broadening and overlap induced by NHWTLP. This process includes constructing a convolution convergence function for GEDI waveforms, denoising GEDI waveform data, transforming one-dimensional ground response functions into two dimensions, and applying amplitude difference regularization between the convolved and observed waveforms. The second is incorporating terrain slope parameters derived from a digital terrain model (DTM) as constraints in the canopy height estimation model to alleviate waveform broadening and overlap in ground response functions caused by topographic effects. The proposed approach enhances the precision of forest canopy height estimation from GEDI data, particularly in areas with complex terrain. The results demonstrate that, under various conditions—including GEDI full-power beams and coverage beams, different terrain slopes, varying canopy closures, and multiple study areas—the retrieved height (rh) model constructed from ground response functions derived via the inverse deconvolution of the transmitted waveforms (IDTW) outperforms the RH (the official height from GEDI L2A) model constructed using RH parameters from GEDI L2A data files in forest canopy height estimation. Specifically, without incorporating terrain slope, the rh model for canopy height estimation using full-power beams achieved a coefficient of determination (R²) of 0.58 and a root mean square error (RMSE) of 5.23 m, compared to the RH model, which had an R² of 0.58 and an RMSE of 5.54 m. After incorporating terrain slope, the rh_g model for full-power beams in canopy height estimation yielded an R² of 0.61 and an RMSE of 5.21 m, while the RH_g model attained an R² of 0.60 and an RMSE of 5.45 m. These findings indicate that the proposed method effectively mitigates waveform broadening and overlap in GEDI waveforms, thereby enhancing the precision of forest canopy height estimation, particularly in areas with complex terrain. This approach provides robust technical support for global-scale forest resource assessment and contributes to the accurate monitoring of carbon dynamics. Full article

Conducting a safety simulation assessment of gas release from the vent mast during the design stage holds significant importance for ship design and system operation safety on LNG-powered vessels. Based on a large-scale practical LNG-powered vessel, this paper employs the CFD method to carry out a safety assessment of the natural gas dispersion, and proposes an optimization design method to address the issue where the vent mast height of large-scale LNG-powered vessels fails to meet specifications. The influencing factors of gas dispersion are discussed. The simulation results indicate that the vent mast height, wind direction, and wind velocity significantly affect the gas dispersion behavior. A lower vent mast height results in a greater risk of flammable gas clouds accumulating on the deck surface. Hazards analysis of the 6 m vent mast condition with windless suggests that a cryogenic explosion hazard zone is formed on the deck centered around the mast position, with the maximum gas concentration reaching 30% and the minimum temperature below −55 °C. The gas cloud spreads along the wind direction, and the extension distance is positively correlated with wind speed. With the increase in wind velocity, the height and volume of flammable gas clouds decrease. When the wind speed is 15 m/s, the volume of the flammable gas cloud is less than half of that at 5 m/s and less than one-tenth of that at 0 m/s. Higher wind velocity can notably promote gas diffusion. Full article

Objectives: This study evaluated how different distributions of isometric conditioning activity (ICA) durations affect countermovement jump (CMJ) performance in highly trained male volleyball players compared to a control condition (CTRL). Methods: Twelve participants performed CTRL and three ICA protocols in a half-back squat: 9 s (3 × 1 × 3 s), 27 s (3 × 3 × 3 s), and 45 s (3 × 5 × 3 s). CMJ height was measured before and at 3, 6, 9, and 12 min post ICA. Results: A two-way repeated measures ANOVA showed significant main effects of time (F = 3.820; p = 0.009) and condition (F = 6.451; p = 0.001), with no significant interaction (F = 1.484; p = 0.138). Post hoc analysis indicated significant CMJ height increases at 9 min [mean difference (MD) = 5.1 ± 0.6 cm; p = 0.045] and 12 min (MD = 6.0 ± 1.4 cm; p = 0.010) post ICA. Moreover, CMJ height was significantly greater in the 27 s (MD = 10.0 ± 0.6 cm; p = 0.002) and 45 s (MD = 7.3 ± 2.0 cm; p = 0.035) conditions compared to the 9 s protocol. Conclusions: Incorporating ICAs of 9 s or 45 s into warm-up routines can enhance CMJ performance, although these durations may elicit different neuromuscular adaptations and movement strategies. Full article

Accurate path-loss characterization in the upper mid-band is critical for 5G/6G outdoor planning, yet classical deterministic expressions lose fidelity at 18 GHz, and purely data-driven regressors offer limited physical insight. We present a physics-guided residual learner that couples a calibrated two-ray model with an XGBoost regressor trained on the deterministic residuals. To enlarge the feature space without promoting overfitting, synthetic samples obtained by perturbing antenna height and ground permittivity within realistic bounds are introduced with a weight of $w=0.3$. The methodology is validated with narrowband measurements collected along two straight 25 m corridors. Under cross-corridor transfer, the hybrid predictor attains $0.59$–$0.62$ dB RMSE and $R^2\ge 0.996$, reducing the error of a pure-ML baseline by half and surpassing deterministic formulas by a factor of four. Small-scale analysis yields decorrelation lengths of 0.23 m and 0.41 m; a cross-correlation peak of unity at $\Delta =0.10$ m confirms the physical coherence of both corridors. We achieve <1 dB error using a small set of field measurements plus simple synthetic data. The method keeps a clear mathematical core and can be extended to other priors, NLOS cases, and semi-open hotspots. Full article

Background: In recent years, the use of compression garments has expanded into sports contexts to enhance performance and optimize post-exercise recovery. One of the most investigated physiological variables for evaluating their effectiveness has been peripheral muscle oxygenation, a crucial indicator of physical performance. However, studies regarding the effects of compression on the upper limbs remain limited and the topic is insufficiently explored. Therefore, the aim of this study was to analyze the effects of compression garments on muscle oxygen saturation (SmO₂) recovery in the biceps brachii after brief maximal isometric contractions. Specifically, physiological responses were compared between two conditions (with and without compression garments), hypothesizing that compression would promote faster and more efficient muscle reoxygenation compared to traditional clothing. Methods: Fourteen male participants (mean age: 24.4 years; mean height: 176.75 cm; mean body mass: 73 kg) performed three 10 s isometric contractions separated by 180 s passive recovery periods under compression (CG) and non-compression (noCG) conditions. SmO₂ was monitored using near-infrared spectroscopy (NIRS), assessing Half-Recovery Time (HRT), Overshoot Amplitude, Initial Slope, and the time constant τ. Results: The compression garment significantly reduced HRT (CG 8.52 s vs. noCG 10.21 s; p = 0.035), significantly increased Overshoot Amplitude (CG 21.40% vs. noCG 7.92%; p = 0.0014), resulted in a greater Initial Slope (CG 2.43%/s vs. noCG 2.09%/s; p = 0.027), and significantly reduced the time constant τ (CG 11.68 s vs. noCG 21.04 s; p < 0.001). Conclusions: The use of compression garments demonstrated significant improvements in post-exercise muscle oxygen saturation, suggesting potential advantages for muscle recovery and positive implications for athletic performance. Full article