Search Results (797)

The latent class model has been proposed as a powerful tool in understanding human behavior for various fields such as social, psychological, behavioral, and biological sciences. However, one important limitation of the latent class model is that it is primarily applied to data with binary responses or categorical responses, making it fail to model real-world data with continuous or negative responses. In many applications, ignoring the weights throws out a lot of potentially valuable information contained in the weights. To address this limitation, we propose a novel generative model, the arbitrary-distribution latent class model (adLCM). Our model enables the generation of data’s response matrix from an arbitrary distribution with a latent class structure. When compared to the latent class model, our adLCM is both more realistic and general. To our knowledge, our adLCM is the first model for latent class analysis with any real-valued responses, including continuous, negative, and signed values, thereby extending the classical latent class model beyond its traditional limitation to binary or categorical outcomes. We investigate the identifiability of the model and propose an efficient algorithm for estimating the latent classes and other model parameters. We show that the proposed algorithm enjoys consistent estimation. The performance of our algorithm is evaluated using both computer-generated data and real-world personality test data. Full article

This study investigated the relationships between inspiratory performance (IP) and glenohumeral rotation in Division 1 Collegiate baseball players (D1CBP). Thirty D1CBP were recruited. The Test of Incremental Respiratory Endurance (TIRE) provides maximal inspiratory pressure (MIP), sustained maximal inspiratory pressure (SMIP), and inspiratory duration (ID). Right and left glenohumeral internal and external rotation (RGHIR, RGHER, LGHIR, and LGHER, respectively) were measured with the shoulder in 90 degrees(d) of abduction. Significant differences between position groups were observed. IP of the entire group was significantly correlated to height, weight, and negatively correlated to right total rotational motion (RTRM) (r = −0.41; p < 0.05). The IP of all pitchers was significantly negatively correlated to both RTRM and LTRM (r = −0.56 to −0.61; p < 0.05). IP of right-handed pitchers was significantly correlated negatively to RGHER (r = −0.83 to −0.93; p < 0.05). IP of left-handed pitchers was significantly correlated negatively to LGHER (r = −0.82; p = 0.04). GH motions are significantly related to the IP of D1CBP. This association may be explained by the involvement of overstretched internal rotators, which act as accessory inspiratory muscles. Full article

To address compacted soils with high power consumption and waterlogging risks in rice–rapeseed rotation areas of the Yangtze River, this study designed a ditching machine combining a stepped cutter head and trapezoidal cleaning blade, where the mechanical synergy between components minimizes energy loss during soil-cutting and -throwing processes. We mathematically modeled soil cutting–throwing dynamics and blade traction forces, integrating soil rheological properties to refine parameter interactions. Discrete Element Method (DEM) simulations and single-factor experiments analyzed impacts of the inner/outer blade widths, blade group distance, and blade opening on power consumption. Results indicated that increasing the inner/outer blade widths (200–300 mm) by expanding the direct cutting area significantly reduced the cutter torque by 32% and traction resistance by 48.6% from reduced soil-blockage drag; larger blade group distance (0–300 mm) initially decreased but later increased power consumption due to soil backflow interference, with peak efficiency at 200 mm spacing; the optimal blade opening (586 mm) minimized the soil accumulation-induced power loss, validated by DEM trajectory analysis showing continuous soil flow. Box–Behnken experiments and genetic algorithm optimization determined the optimal parameters: inner blade width: 200 mm; outer blade width: 300 mm; blade group distance: 200 mm; and blade opening: 586 mm, yielding a simulated power consumption of 27.07 kW. Field tests under typical 18.7% soil moisture conditions confirmed a <10% error between simulated and actual power consumption (28.73 kW), with a 17.3 ± 0.5% reduction versus controls. Stability coefficients for the ditch depth, top/bottom widths exceeded 90%, and the backfill rate was 4.5 ± 0.3%, ensuring effective drainage for rapeseed cultivation. This provides practical theoretical and technical support for efficient ditching equipment in rice–rapeseed rotations, enabling resource-saving design for clay loam soils. Full article

This study investigated the effects of a single-night sleep extension protocol on physical performance and cognitive function in physically active university students across different times of day. Using a within-subjects, counterbalanced crossover design, 24 physically active university students (17 males, 7 females; age: 22.7 ± 1.6 years) completed performance assessments under normal-sleep and sleep-extension conditions. Participants’ sleep was monitored via wrist actigraphy, and a comprehensive assessment battery comprising vertical jumps, Y-Balance tests, medicine-ball throws, 5 m shuttle-run tests, reaction-time tests, and digit-cancellation tests was administered at baseline (8 PM), morning (8 AM), and afternoon (4 PM). Sleep extension increased total sleep time by approximately 55 min (531.3 ± 56.8 min vs. 476.5 ± 64.2 min; p < 0.001, d = 0.91). Significant improvements were observed in 5 m shuttle-run performance at 8 AM (best distance: 102.8 ± 11.9 m vs. 93.3 ± 8.5 m, p < 0.001, d = 0.93; fatigue index: 13.1 ± 8.3% vs. 21.2 ± 9.5%, p < 0.001, d = 0.90), squat-jump heights (28.2 ± 8.0 cm vs. 26.3 ± 7.2 cm, p = 0.005, d = 0.25), simple reaction time (252.8 ± 55.3 ms vs. 296.4 ± 75.2 ms, p < 0.001, d = 0.66), and digit-cancellation performance (67.6 ± 12.6 vs. 63.0 ± 10.0 targets, p = 0.006, d = 0.40). Sleep extension significantly enhances both physical and cognitive performance in physically active individuals, with effects more pronounced during morning hours, partially attenuating typical circadian performance decline and establishing sleep extension as an effective, non-pharmacological strategy for optimizing performance capabilities. Full article

Farmers commonly throw away tomato leaves when they harvest tomatoes, although they are a good source of vital biomolecules. ZnO nanoparticles (ZnO NPs) enhance plant growth by regulating abiotic stress and scavenging reactive oxygen species. In the current article, the activities of five antioxidant enzymes—glutathione reductase (GR), peroxidase (POX), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT)—were determined spectrophotometrically to study the interaction between foliar fertilization of ZnO NPs and salt stress in tomato plants. We employed the next-generation sequencing (NGS) technique to investigate the gene expression. It was also used to generate a de novo supertranscript and then determine the sequences modulated by treatments. Differential expression analysis was used to identify increased and reduced gene clusters, and gene enrichment analysis was used to identify over- and under-expressed genes under the treatment. Gene Ontology (GO) was used to identify the functions and regulatory pathways of the differentially expressed genes (DEGs). It was found that ZnO nanoparticles had the capability to overcome the reduction in antioxidant enzyme production levels in the case of the salinity-stressed treatments and enhance the secretion of those enzymes in the non-stressed but sprayed treatments. The ZnO NPs also enhanced the reduction in stress-responsive genes associated with salt stress resistance. The results revealed the impact of ZnO nanoparticles on alleviating the salinity stress reductive effects in antioxidative enzymes and regulating the mechanism by which metabolically relevant genes adaptively respond to salt stress in tomato plants. So, spraying tomato plants (stressed or not) with ZnO NPs is a promising agricultural technique in improving different metabolic pathways that are responsible for plants’ resistance. Full article

Objectives: The primary objective of this study was to determine whether motor disorders are significantly more prevalent in children with Autism Spectrum Disorder (ASD) without co-occurring genetic or neurological conditions compared to neurotypical children. Another aim was to explore the applicability of the MABC-2 test for assessing motor skills in a Polish cohort of children with ASD. Additionally, this study sought to develop a basic framework for motor skill assessment in children with autism. Methods: This study included 166 Caucasian children, both sexes, aged 5–12 years, without intellectual disability (IQ ≥ 70), without concomitant genetic or neurological disorders, particularly epilepsy or cerebral palsy. The study group consisted of children with ASD (n = 71), and the control group consisted of neurotypical children (n = 95). The participants were assessed with the Movement Assessment Battery for Children–second edition (MABC-2), MABC-2 checklist and the Developmental Coordination Disorder Questionnaire (DCDQ), used as a reference point. Results: The children with ASD obtained significantly lower MABC-2 test results in all subtests in comparison with the control group. The children with suspected or diagnosed coordination disorders were characterized by a significantly greater number of co-occurring non-motor factors than the other participants of this study. MABC-2 test showed greater consistency with DCDQ than with the MABC-2 questionnaire. Conclusions: Children with ASD present a lower level of manual dexterity and balance and greater difficulties in performing tasks, including throwing and catching, in comparison with neurotypical children. The MABC-2 test with the MABC-2 checklist and DCDQ questionnaire constitute a complementary diagnostic tool. Full article

Maximal and explosive strength—defined as the ability to rapidly generate high levels of force—are widely recognized as critical for performance in strength–power sports such as track and field throwing. However, their interrelationship remains insufficiently examined, particularly in the upper body of elite athletes. This study examined the relationship between early force production (≤250 ms, subdivided into early phase: 0–100 ms; late phase: 100–250 ms) and peak isometric upper-body push and pull force in elite Swedish track and field throwers. A total of 30 athletes (17 females, 13 males; aged 18–34 years), all competing nationally or internationally in discus, hammer, shot put, or javelin, participated in a cross-sectional assessment. Isometric force was measured during bench press (push) and supine bench row (pull) using a custom-built device. Force output was recorded at 50, 100, 150, 200, and 250 ms, along with peak force. The results showed a progressive increase in the correlation between force at early time points and peak force. Associations were weak to moderate at 50–100 ms (r = 0.07–0.55) and became strong to very strong at 150–250 ms (r = 0.64–0.92). These patterns were consistent across sexes and test types. The findings suggest that maximal strength becomes increasingly important as force production time extends beyond 100 ms. Coaches may benefit from assessing both early and peak force characteristics to inform strength profiling and guide training focus, though further research is needed to determine their impact on performance. Full article

Extensive attention has been given to children’s play spaces in public environments. Still, there exists a research need to devise a more comprehensive and structured design framework for space design addressing more comprehensive and structured activity modeling capabilities. The Context-Based Activity Modeling (CBAM) has been proposed as a framework for service design where activities are represented by elements like action verb, actors, object, tool, and contexts, where context is further represented by goal, relevant structure, physical, and psychological contexts. In this paper, children’s play activities such as throw, run, chase, hide, seek, and seize as observed in a community courtyard setting have been represented and interrogated using the CBAM method. Then, six specific design strategies have been derived for enhancing children’s play space design. As demonstrated in this way, CBAM is proposed as a framework for activity-centered space design for child playground. Experiential sustainability of children’s play activities are supported by play space design fully addressing detailed context elements of CBAM. Full article

Olympic women’s judo has increased in complexity and competitiveness, demanding detailed tactical analysis. This observational study aimed to examine the relationship between the results of combats (Wazari [half point] vs. Ippon [full point]) and the techniques used in women’s judo combats in the Rio 2016 and Tokyo 2020 Olympic Games. A significant association was found between technique type and contest outcome (χ² = 40.004, df = 6, p < 0.001): Nage Waza (throwing techniques) produced 92.3% of Wazari, whereas Katame Waza (groundwork techniques) accounted for 61.1% of Ippon. Subgroup analysis confirmed these relationships (χ² = 17.217, df = 6, p = 0.009; Cramer’s V = 0.745), with Ashiwaza (foot/leg techniques) dominating Wazari. Uchimata was the most frequently used technique in the repechage (20%), bronze medal (22.6%), and final (23.1%) matches. In lightweights, Katame Waza dominated Ippon in finals (53.8%, χ² = 4.000, p = 0.046), while Nage Waza secured all Wazari. Middleweights also showed strong associations (χ² = 14.745, df = 1, p < 0.001; 93.9% of Wazari by Nage Waza). Although no significant association was found for heavyweights (χ² = 7.535, df = 1, p = 0.095), Katame Waza prevailed in Ippon (69.2%). These findings provide a tactical framework for tailoring technique-specific training by weight category and tournament phase to optimize outcomes in elite female judo. Full article

Aiming at the problem that the whole row of reciprocating seedling picking mechanism is prone to inertial impacts during operation due to its excessive mass, causing seedling damage and positioning errors, this study builds a motion control system with a PLC controller as the core and proposes a composite motion control strategy based on planned S-curve acceleration and deceleration and fuzzy PID to achieve rapid response, precise positioning, and smooth operation of the seedling picking mechanism. By establishing the objective function and constraint conditions and taking into account the dynamic change of the seedling picking displacement, the S-curve acceleration and deceleration control algorithm is planned in six and seven stages to meet the requirements of a smooth transition of the speed and continuous change of the acceleration curve of the seedling picking mechanism during movement. A fuzzy PID positioning control system is designed, the control system transfer function is constructed, and fuzzy rules are formulated to dynamically compensate for the error and its rate of change to meet the requirements of fast response and no overshoot oscillation of the positioning control system. The speed and acceleration of the seedling picking mechanism under the six-segment and seven-segment S-curve acceleration and deceleration motion control conditions were simulated using MATLAB2024a simulation software and compared with the trapezoidal acceleration and deceleration motion control. The planned S-curve acceleration and deceleration control algorithm has a more stable control effect on the seedling picking mechanism when it operates under the conditions of the dynamic change of the displacement, and it meets the design requirements of seedling picking efficiency. The positioning control system was modeled and simulated using the Simulink simulation platform. When KP = 15, KI = 3, and KD = 1, the whole-row seedling picking control system ran stably, responded quickly, and had no overshoot. Compared with the PID control system with fixed parameters, the fuzzy PID control system reduced the time consumption in the rising stage by 24.5% and shortened the overall stabilization process by 17.6%. The zero overshoot characteristic was ensured, and the response speed was faster. When a disturbance signal is added, the overshoot of the fuzzy PID control system is reduced by 2.4%, and the response speed is increased by 6.8% compared with the fixed-parameter PID control system. The dynamic response rate and anti-disturbance performance are better than those of the fixed-parameter PID control system. A bench comparison test was carried out. The results showed that the S-curve acceleration and deceleration motion control algorithm reduced the average mass loss rate of seedlings by 46.19% compared with the trapezoidal acceleration and deceleration motion control algorithm, and the seedling picking efficiency met the design requirements. Fuzzy PID positioning control was used, and the maximum displacement error of the end effector during seedling picking was −1.4 mm, and the average relative error rate was 0.22%, which met the positioning accuracy requirements of the end effector in the X-axis direction and verified the stability and accuracy of the designed control system. The designed control system was tested in the field, and the average comprehensive success rate of seedling picking and throwing reached 96.2%, which verified the feasibility and practicality of the control system. Full article

This study investigated the effect of the angle between the blade and the inclined disc on particle trajectory correction during ejection from an organic fertilizer side-throwing device. Using the inclined disc device as the test subject, a blade-based coordinate system was established to model the complex relative particle motion under combined disc and blade inclination. Particle dynamics and blade forces were analyzed quadrantally, enabling the development of a mechanical model and the derivation of displacement equations. Numerical simulation, virtual simulation, and experimental testing yielded the following results: Under the current device parameters, the relative velocity between particles and the blade reaches its maximum when the angle between the blade and the inclined disc is 80°. Within the angle range from 65° to 85°, as the angle increases, the scattering angle of single-sided discs monotonically decreases, while that of dual-sided discs monotonously increases. At an angle of 65°, the trajectories of the dual-sided disc flows tend to converge. At 80°, the flow is at the critical point between convergence and divergence. The effective throwing distance first increases and then decreases, reaching a maximum at an angle of 80°. This study clarifies the relationship between the angle correction of blade–disc inclination and particle velocity and trajectory on the blade, providing a reliable mathematical model and simulation method for similar studies in the field of inclined disc centrifugal material ejection. Full article

Tests assessing physical qualities are regularly used in youth rugby league teams for various functions. However, the utility of such tests is under-explored in this population. In this way, tests are commonly examined in terms of how well they can differentiate performances between groups that are expected to differ and how they relate to outcomes in actual competitive contexts. Therefore, the purpose of this exploratory study was to investigate the discriminative validity and relationships to match performance metrics of frequently used tests to assess physical qualities in male, adolescent rugby league players. Anthropometric (standing height and body mass) and fitness-related (20 m linear sprint, 505-Agility Test, L-run Test, medicine ball throw, countermovement jump, one-repetition maximum back squat, bench press, and prone row tests, and Multistage Fitness Test) physical qualities were measured using common tests in 42 players (16.1 ± 1.3 years). Test outcomes were compared between players in different age and positional groups for discriminative validity analyses. Relationships between test outcomes and match performance metrics gathered via global positioning system and video analysis were also determined. Compared to younger players (14–15 years), older players (16–18 years) had significantly better fitness-related physical qualities (p < 0.05, d = −1.78–1.66), but similar anthropometric qualities (p > 0.05, d = −0.45–0.20). Significant, moderate correlations (p < 0.05, r = 0.56–0.70) were found between (1) one-repetition maximum (1-RM) back squat and relative (per min) high-speed running distance and maximum velocity in matches; (2) 20-m sprint time and relative total distance; (3) 505-Agility Test time and relative line breaks; and (4) height and relative unsuccessful tackles. Consequently, commonly used fitness-related tests demonstrate discriminative validity in detecting differences between age groups, with standing height and the 1-RM back squat showing promising utility given their associations with key match metrics in adolescent rugby league players. Full article

This study explores how artificial intelligence (AI) can support the evaluation of assistive technology outcomes in adaptive sports, focusing on elite boccia athletes with disabilities. Using a multi-stage motion analysis framework, we integrated OpenPose, ViTPose, and Lifting to estimate seated joint kinematics with greater precision. Match footage from 12 athletes at the 2018 Asia-Pacific Boccia Open was analyzed across five biomechanical phases: preparation, acceleration, peak, release, and follow-through. AI-enhanced 2D and 3D pose estimation methods were applied to assess throwing strategies and motor variability. ViTPose outperformed OpenPose in joint detection accuracy (F1-score: 85% vs. 79.5%), while Lifting improved 3D estimation by reducing joint position error by 16%. Principal Component Analysis revealed greater movement consistency in overhand throws compared to underhand techniques. The proposed pipeline provides an interpretable and scalable method for measuring performance, motor control, and strategy-specific movement outcomes in boccia, offering practical applications for evidence-based coaching, athlete classification, and the design of inclusive assistive sport technologies. Full article

Quinoa is renowned for its high nutritional value, which not only meets the nutritional needs of the human body but also makes it a suitable option for individuals with diabetes and celiac disease due to its low sugar and gluten-free characteristics. In China, the primary cultivation regions of quinoa are the Tibetan Plateau, the Yunnan–Guizhou Plateau, and Northwest China, which are predominantly characterized by hilly and mountainous terrain, resulting in the gradual development of mechanized harvesting processes. The efficacy of the mechanized harvesting process in these regions is suboptimal, exhibiting poor clearance and efficiency. In this paper, the design and MBD-EDEM coupling analysis of the quinoa combine harvester’s cleaning and screening mechanism is carried out to simulate the cleaning process of quinoa threshing materials. The results show that the vibrating screen can complete the forward sliding and dispersed throwing up of the materials and effectively avoid the accumulation of the threshing materials. The coupling results of the permeability of each material in the cleaning and screening mechanism, as well as the vibrating screen movement condition, indicate that when the herringbone screen opening degree is set in the range of 15° to 30°, the cleaning and screening device can achieve a high cleaning efficiency while maintaining a low impurity rate. Field trial data further confirm that within this opening range, the cleaning effect and efficiency both exhibit significant advantages. Full article

Compact, broadband, multi-channel RF chips with low loss and high integration are required for high-performance phased-array systems. Presented in this paper is a four-channel, multifunction RF chip operating in the 5–18 GHz frequency range that integrates broadband phase shifting, amplitude control, power amplification, and switching functions. The chip is designed to have flip-chip bonding and stacked gold bumps to enable the compact 3D integration of the GaAs pHEMT and Si-CMOS. To ensure high-density interconnects with minimal parasitic effects, a fan-in redistribution process is implemented. The RF front-end part of this chip, fabricated through a 0.15 µm GaAs pHEMT process, integrates 6-bit digital phase shifters, 6-bit digital attenuators, low-noise amplifiers (LNAs), power amplifiers (PAs), and single-pole double-throw (SPDT) switches. To enhance multi-channel isolation and reduce crosstalk between RF chips and digital circuits, high isolation techniques, including a ground-coupled shield layer in the fan-in process and on-chip shield cavities, are utilized, which achieve isolation levels greater than 41 dB between adjacent RF channels. The measurement results demonstrate a reception gain of 0 dB with ±0.6 dB flatness, an NF below 11 dB, and transmit gain of more than 10 dB, with a VSWR of below 1.6 over the entire 5–18 GHz frequency band. The 6-bit phase shifter achieves a root mean square (RMS) phase error below 2.5° with an amplitude variation of less than 0.8 dB, while the 6-bit attenuator exhibits an RMS attenuation error of below 0.5 dB and a phase variation of less than 7°. The RF and digital chips are heterogeneously integrated using flip-chip and fan-in technology, resulting in a compact chip size of 6.2 × 6.2 × 0.33 mm³. These results validate that this is a compact, high-performance solution for advanced phased-array radar applications. Full article