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Search Results (147)

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Keywords = powerful goodness-of-fit test

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14 pages, 6959 KiB  
Article
Power–Cadence Relationships in Cycling: Building Models from a Limited Number of Data Points
by David M. Rouffet, Briar L. Rudsits, Michael W. Daniels, Temi Ariyo and Christophe A. Hautier
Signals 2025, 6(3), 32; https://doi.org/10.3390/signals6030032 - 10 Jul 2025
Viewed by 594
Abstract
Accurate modeling of the power–cadence relationship is essential for assessing maximal anaerobic power (Pmax) of the lower limbs. Experimental data points from Force–Velocity tests during cycling do not always reflect the maximal and cadence-specific power individuals can produce. The quality of the models [...] Read more.
Accurate modeling of the power–cadence relationship is essential for assessing maximal anaerobic power (Pmax) of the lower limbs. Experimental data points from Force–Velocity tests during cycling do not always reflect the maximal and cadence-specific power individuals can produce. The quality of the models and the accuracy of Pmax estimation is potentially compromised by the inclusion of non-maximal data points. This study evaluated a novel residual-based filtering method that selects five strategically located, maximal data points to improve model fit and Pmax prediction. Twenty-three recreationally active male participants (age: 26 ± 5 years; height: 178 ± 5 cm; body mass: 73 ± 11 kg) completed a Force–Velocity test consisting of multiple maximal cycling efforts on a stationary ergometer. Power and cadence data were used to generate third-order polynomial models: from all data points (High Number, HN), from the highest power value in each 5-RPM interval (Moderate Number, MN), and from five selected data points (Low Number, LN). The LN model yielded the best goodness of fit (R2 = 0.995 ± 0.008; SEE = 29 ± 15 W), the most accurate estimates of experimentally measured peak power (mean absolute percentage error = 1.45%), and the highest Pmax values (1220 ± 168 W). Selecting a limited number of maximal data points improves the modeling of individual power–cadence relationships and Pmax assessment. Full article
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19 pages, 1419 KiB  
Article
Revisiting the Relationship Between the Scale Factor (a(t)) and Cosmic Time (t) Using Numerical Analysis
by Artur Chudzik
Mathematics 2025, 13(14), 2233; https://doi.org/10.3390/math13142233 - 9 Jul 2025
Viewed by 392
Abstract
Background: Current cosmological fits typically assume a direct relation between cosmic time (t) and the scale factor (a(t)), yet this ansatz remains largely untested across diverse observations. Objectives: We (i) test whether a single power-law scaling [...] Read more.
Background: Current cosmological fits typically assume a direct relation between cosmic time (t) and the scale factor (a(t)), yet this ansatz remains largely untested across diverse observations. Objectives: We (i) test whether a single power-law scaling (a(t)tα) can reproduce late- and early-time cosmological data and (ii) explore whether a dynamically evolving (α(t)), modeled as a scalar–tensor field, naturally induces directional asymmetry in cosmic evolution. Methods: We fit a constant-α model to four independent datasets: 1701 Pantheon+SH0ES supernovae, 162 gamma-ray bursts, 32 cosmic chronometers, and the Planck 2018 TT spectrum (2507 points). The CMB angular spectrum is mapped onto a logarithmic distance-like scale (μ=log10D), allowing for unified likelihood analysis. Each dataset yields slightly different preferred values for H0 and α; therefore, we also perform a global combined fit. For scalar–tensor dynamics, we integrate α(t) under three potentials—quadratic, cosine, and parity breaking (α3sinα)—and quantify directionality via forward/backward evolution and Lyapunov exponents. Results: (1) The constant-α model achieves good fits across all datasets. In combined analysis, it yields H070kms1Mpc1 and α1.06, outperforming ΛCDM globally (ΔAIC401254), though ΛCDM remains favored for some low-redshift chronometer data. High-redshift GRB and CMB data drive the improved fit. Numerical likelihood evaluations are approximately three times faster than for ΛCDM. (2) Dynamical α(t) models exhibit time-directional behavior: under asymmetric potentials, forward evolution displays finite Lyapunov exponents (λL103), while backward trajectories remain confined (λL<0), realizing classical arrow-of-time emergence without entropy or quantum input. Limitations: This study addresses only homogeneous background evolution; perturbations and physical derivations of potentials remain open questions. Conclusions: The time-scaling approach offers a computationally efficient control scenario in cosmological model testing. Scalar–tensor extensions naturally introduce classical time asymmetry that is numerically accessible and observationally testable within current datasets. Code and full data are available. Full article
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20 pages, 23523 KiB  
Article
A Wrist Brace with Integrated Piezoelectric Sensors for Real-Time Biomechanical Monitoring in Weightlifting
by Sofia Garcia, Ethan Ortega, Mohammad Alghamaz, Alwathiqbellah Ibrahim and En-Tze Chong
Micromachines 2025, 16(7), 775; https://doi.org/10.3390/mi16070775 (registering DOI) - 30 Jun 2025
Viewed by 370
Abstract
This study presents a self-powered smart wrist brace integrated with a piezoelectric sensor for real-time biomechanical monitoring during weightlifting activities. The system was designed to quantify wrist flexion across multiple loading conditions (0 kg, 0.5 kg, and 1.0 kg), leveraging mechanical strain-induced voltage [...] Read more.
This study presents a self-powered smart wrist brace integrated with a piezoelectric sensor for real-time biomechanical monitoring during weightlifting activities. The system was designed to quantify wrist flexion across multiple loading conditions (0 kg, 0.5 kg, and 1.0 kg), leveraging mechanical strain-induced voltage generation to capture angular displacement. A flexible PVDF film was embedded within a custom-fitted wrist brace and tested on male and female participants performing controlled wrist flexion. The resulting voltage signals were analyzed to extract root-mean-square (RMS) outputs, calibration curves, and sensitivity metrics. To interpret the experimental results analytically, a lumped-parameter cantilever beam model was developed, linking wrist flexion angles to piezoelectric voltage output based on mechanical deformation theory. The model assumed a linear relationship between wrist angle and induced strain, enabling theoretical voltage prediction through simplified material and geometric parameters. Model-predicted voltage responses were compared with experimental measurements, demonstrating a good agreement and validating the mechanical-electrical coupling approach. Experimental results revealed consistent voltage increases with both wrist angle and applied load, and regression analysis demonstrated strong linear or mildly nonlinear fits with high R2 values (up to 0.994) across all conditions. Furthermore, surface plots and strain sensitivity analyses highlighted the system’s responsiveness to simultaneous angular and loading changes. These findings validate the smart wrist brace as a reliable, low-power biomechanical monitoring tool, with promising applications in injury prevention, rehabilitation, and real-time athletic performance feedback. Full article
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28 pages, 8777 KiB  
Article
Exploring Carbon-Fiber UAV Structures as Communication Antennas for Adaptive Relay Applications
by Cristian Vidan, Andrei Avram, Lucian Grigorie, Grigore Cican and Mihai Nacu
Electronics 2025, 14(12), 2473; https://doi.org/10.3390/electronics14122473 - 18 Jun 2025
Viewed by 508
Abstract
This study investigates the electromagnetic performance of two carbon fiber monopole antennas integrated into a UAV copter frame, with emphasis on design adaptation, impedance matching, and propagation behavior. A comprehensive experimental campaign was conducted to characterize key parameters such as center frequency, bandwidth, [...] Read more.
This study investigates the electromagnetic performance of two carbon fiber monopole antennas integrated into a UAV copter frame, with emphasis on design adaptation, impedance matching, and propagation behavior. A comprehensive experimental campaign was conducted to characterize key parameters such as center frequency, bandwidth, gain, VSWR, and S11. Both antennas exhibited dual-band resonance at approximately 381 MHz and 1.19 GHz, each achieving a 500 MHz bandwidth where VSWR ≤ 2. The modified antenna achieved a minimum reflection coefficient of –14.6 dB and a VSWR of 1.95 at 381.45 MHz, closely aligning with theoretical predictions. Gain deviations between measured (0.15–0.19 dBi) and calculated (0.19 dBi) values remained within 0.04 dB, while received power fluctuations did not exceed 1.3 dB under standard test conditions despite the composite material’s finite conductivity. Free-space link-budget tests at 0.5 m and 2 m of separation revealed received-power deviations of 0.9 dB and 1.3 dB, respectively, corroborating the Friis model. Radiation pattern measurements in both azimuth and elevation planes confirmed good directional behavior, with minor side lobe variations, where Antenna A displayed variations between 270° and 330° in azimuth, while Antenna B remained more uniform. A 90° polarization mismatch led to a 15 dBm signal drop, and environmental obstructions caused losses of 9.4 dB, 12.6 dB, and 18.3 dB, respectively, demonstrating the system’s sensitivity to alignment and surroundings. Additionally, signal strength changes observed in a Two-Ray propagation setup validated the importance of ground reflection effects. Small-scale fading analysis at 5 m LOS indicated a Rician-distributed envelope with mean attenuation of 53.96 dB, σdB = 5.57 dB, and a two-sigma interval spanning 42.82 dB to 65.11 dB; the fitted K-factor confirmed the dominance of the LOS component. The findings confirm that carbon fiber UAV frames can serve as effective directional antenna supports, providing proper alignment and tuning. These results support the future integration of lightweight, structure-embedded antennas in UAV systems, with potential benefits in communication efficiency, stealth, and design simplification. Full article
(This article belongs to the Special Issue Unmanned Aircraft Systems with Autonomous Navigation, 2nd Edition)
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11 pages, 484 KiB  
Article
Comparative Study in Physical Fitness in Recreative Young Padel Players
by Ana Pereira, Luis Leitão, Diogo L. Marques, Daniel A. Marinho and Henrique P. Neiva
J. Funct. Morphol. Kinesiol. 2025, 10(2), 214; https://doi.org/10.3390/jfmk10020214 - 5 Jun 2025
Viewed by 765
Abstract
Background: In recent years, padel-based interventions have been widely applied in junior and elite players of both genders concerning athletic performance, whereas evidence of their efficacy in trials that use simple randomization has not been well established. This study aimed to compare the [...] Read more.
Background: In recent years, padel-based interventions have been widely applied in junior and elite players of both genders concerning athletic performance, whereas evidence of their efficacy in trials that use simple randomization has not been well established. This study aimed to compare the effects of 8 weeks of padel training (PD) on the strength and power of untrained healthy children. Methods: Twenty-five children aged 11–15 years (12.36 ± 1.15 years) were randomly assigned into experimental (PD) (nine boys and five girls: 1.58 ± 0.04 m; 50.00 ± 6.75 kg; and 19.96 ± 1.95 kg/m2) and control (CT) (seven boys and four girls: 1.60 ± 0.05 m; 56.92 ± 2.75 kg; and 21.61 ± 1.02 kg/m2) groups. The PD group trained twice a week for 8 weeks, and the CT group did not follow any training program and did not participate in regular exercise or sports. Countermovement jump, medicine ball throw, handgrip, and 5 m sprint test results were measured at baseline and after the intervention in the padel sport group. Results: The results showed a significant interaction for training-induced responses in the sprint test (T5) (F = 10.55, p = 0.004, η2 = 0.31). No significant interactions were observed for handgrip strength (HG) (F = 3.90, p=0.06), the medicine ball throw (MBT) (F = 0.851, p = 0.37, η2 = 0.04), and the countermovement jump (F = 1.04, p =0.32, η2 = 0.04), with clear improvements from pre- to post-training in the PD group. After 8 weeks of training, the PD group showed increased performance in handgrip strength (p = 0.004), while the CT group had decreased velocity post-training (p = 0.011). Conclusions: The individual results in the PD group showed an improvement, which suggests that the practice of padel seems to be a good strategy for improving one’s fitness. It is suggested that 8 weeks of PD seem to be effective in improving strength- and power-related variables in healthy, untrained children. This could be considered an alternative to traditional sports to improve the body fitness of young children and should be applied in school-based programs and the sports club community. Also, more high-quality RCTs are needed in the future. Full article
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29 pages, 510 KiB  
Article
Statistical Inference and Goodness-of-Fit Assessment Using the AAP-X Probability Framework with Symmetric and Asymmetric Properties: Applications to Medical and Reliability Data
by Aadil Ahmad Mir, A. A. Bhat, S. P. Ahmad, Badr S. Alnssyan, Abdelaziz Alsubie and Yashpal Singh Raghav
Symmetry 2025, 17(6), 863; https://doi.org/10.3390/sym17060863 - 1 Jun 2025
Viewed by 463
Abstract
Probability models are instrumental in a wide range of applications by being able to accurately model real-world data. Over time, numerous probability models have been developed and applied in practical scenarios. This study introduces the AAP-X family of distributions—a novel, flexible framework for [...] Read more.
Probability models are instrumental in a wide range of applications by being able to accurately model real-world data. Over time, numerous probability models have been developed and applied in practical scenarios. This study introduces the AAP-X family of distributions—a novel, flexible framework for continuous data analysis named after authors Aadil Ajaz and Parvaiz. The proposed family effectively accommodates both symmetric and asymmetric characteristics through its shape-controlling parameter, an essential feature for capturing diverse data patterns. A specific subclass of this family, termed the “AAP Exponential” (AAPEx) model is designed to address the inflexibility of classical exponential distributions by accommodating versatile hazard rate patterns, including increasing, decreasing and bathtub-shaped patterns. Several fundamental mathematical characteristics of the introduced family are derived. The model parameters are estimated using six frequentist estimation approaches, including maximum likelihood, Cramer–von Mises, maximum product of spacing, ordinary least squares, weighted least squares and Anderson–Darling estimation. Monte Carlo simulations demonstrate the finite-sample performance of these estimators, revealing that maximum likelihood estimation and maximum product of spacing estimation exhibit superior accuracy, with bias and mean squared error decreasing systematically as the sample sizes increases. The practical utility and symmetric–asymmetric adaptability of the AAPEx model are validated through five real-world applications, with special emphasis on cancer survival times, COVID-19 mortality rates and reliability data. The findings indicate that the AAPEx model outperforms established competitors based on goodness-of-fit metrics such as the Akaike Information Criteria (AIC), Schwartz Information Criteria (SIC), Akaike Information Criteria Corrected (AICC), Hannan–Quinn Information Criteria (HQIC), Anderson–Darling (A*) test statistic, Cramer–von Mises (W*) test statistic and the Kolmogorov–Smirnov (KS) test statistic and its associated p-value. These results highlight the relevance of symmetry in real-life data modeling and establish the AAPEx family as a powerful tool for analyzing complex data structures in public health, engineering and epidemiology. Full article
(This article belongs to the Section Mathematics)
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28 pages, 3803 KiB  
Article
Comparative Analysis of Five Numerical Methods and the Whale Optimization Algorithm for Wind Potential Assessment: A Case Study in Whittlesea, Eastern Cape, South Africa
by Ngwarai Shambira, Lwando Luvatsha and Patrick Mukumba
Processes 2025, 13(5), 1344; https://doi.org/10.3390/pr13051344 - 27 Apr 2025
Viewed by 492
Abstract
This study explores the potential of wind energy to address electricity shortages in South Africa, focusing on the Ekuphumleni community in Whittlesea. Given the challenges of expanding the national grid to these areas, wind energy is considered to be a feasible alternative to [...] Read more.
This study explores the potential of wind energy to address electricity shortages in South Africa, focusing on the Ekuphumleni community in Whittlesea. Given the challenges of expanding the national grid to these areas, wind energy is considered to be a feasible alternative to provide clean, renewable energy and reduce fossil fuel dependence in this community. This research evaluates wind potential utilizing the two-parameter Weibull distribution, with scale and shape parameters estimated by five traditional numerical methods and one metaheuristic optimization technique: whale optimization algorithm (WOA). Goodness-of-fit tests, such as the coefficient of determination (R2) and wind power density error (WPDE), were utilized to determine the best method for accurately estimating Weibull scale and shape parameters. Furthermore, net fitness, which combines R2 and WPDE, was employed to provide a holistic assessment of overall performance. Whittlesea showed moderate wind speeds, averaging 3.88 m/s at 10 m above ground level (AGL), with the highest speeds in winter (4.87 m/s) and optimum in July. The WOA method outperformed all five numerical methods in this study in accurately estimating Weibull distribution parameters. Interestingly, the openwind method (OWM), a numerical technique based on iterative methods, and the Brent method showed comparable performance to WOA. The wind power density was 67.29 W/m2, categorizing Whittlesea’s potential as poor and suitable for small-scale wind turbines. The east wind patterns favor efficient turbine placement. The study recommends using augmented wind turbines for the site to maximize energy capture at moderate speeds. Full article
(This article belongs to the Special Issue Advanced Technologies of Renewable Energy Sources (RESs))
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15 pages, 15656 KiB  
Article
Oxidation of the Alloy Based on the Intermetallic Phase FeAl in the Temperature Range of 700–1000 °C in Air and Possibilities of Practical Application
by Janusz Cebulski, Dorota Pasek, Maria Sozańska, Magdalena Popczyk, Jadwiga Gabor and Andrzej Swinarew
Materials 2025, 18(8), 1835; https://doi.org/10.3390/ma18081835 - 16 Apr 2025
Viewed by 456
Abstract
The paper presents the results of oxidation tests on the alloy based on the intermetallic phase, Fe40Al5Cr0.2TiB, in the air at 700–1000 °C temperature. The kinetics of corrosion processes were determined, the surface condition after oxidation was assessed, and the type and morphology [...] Read more.
The paper presents the results of oxidation tests on the alloy based on the intermetallic phase, Fe40Al5Cr0.2TiB, in the air at 700–1000 °C temperature. The kinetics of corrosion processes were determined, the surface condition after oxidation was assessed, and the type and morphology of the oxides formed were determined. In addition, the paper presents the possibility of applying the technology of surfacing Fe40Al5Cr0.2TiB alloy on the surface of steel grade S235JR as a protective coating that is resistant to high temperatures. The process was carried out using the TIG method by direct current (DC). After the surfacing, the structure of the surfacing weld made of the tested material on the base of structural steel grade S235JR was determined. It was found that a protective Al2O3 oxide layer is formed on the surface of the oxidized alloy based on the intermetallic phase from the FeAl system, and the oxidation kinetics have a parabolic course. Moreover, it was found that the morphology of the oxides formed on the surface varies depending on the oxidation temperature, which clearly indicates a different mechanism of oxide layer formation. The formation of a stable α-Al2O3 oxide variety on the surface of the Fe40Al5Cr0.2TiB alloy protects the material from further corrosion, which favors the application of this alloy on structures and fittings operating at elevated temperatures. The aim of the research was to use the Fe40Al5Cr0.2TiB alloy with very good oxidation resistance as a layer overlay on ordinary quality S235JR steel. In this way, conditions were created that fundamentally changed the surface condition (structure and physicochemical properties) of the system: steel as a substrate—intermetallic phase Fe40Al5Cr0.2TiB as a surfacing layer, in order to increase resistance to high-temperature corrosion and erosion (in the environment of gases and solid impurities in gases) often occurring in corrosive environments, especially in the power industry (boilers, pipes, installation elbows) and the chemical industry (fittings). At the same time, the surfacing method used is one of the cheapest methods of changing the surface properties of the material and regenerating or repairing the native material with a material with better properties, especially for applications in high-temperature corrosion conditions. Full article
(This article belongs to the Special Issue Achievements in Foundry Materials and Technologies)
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21 pages, 2029 KiB  
Article
Comparing Frequentist and Bayesian Methods for Factorial Invariance with Latent Distribution Heterogeneity
by Xinya Liang, Ji Li, Mauricio Garnier-Villarreal and Jihong Zhang
Behav. Sci. 2025, 15(4), 482; https://doi.org/10.3390/bs15040482 - 7 Apr 2025
Viewed by 561
Abstract
Factorial invariance is critical for ensuring consistent relationships between measured variables and latent constructs across groups or time, enabling valid comparisons in social science research. Detecting factorial invariance becomes challenging when varying degrees of heterogeneity are present in the distribution of latent factors. [...] Read more.
Factorial invariance is critical for ensuring consistent relationships between measured variables and latent constructs across groups or time, enabling valid comparisons in social science research. Detecting factorial invariance becomes challenging when varying degrees of heterogeneity are present in the distribution of latent factors. This simulation study examined how changes in latent means and variances between groups influence the detection of noninvariance, comparing Bayesian and maximum likelihood fit measures. The design factors included sample size, noninvariance levels, and latent factor distributions. Results indicated that differences in factor variance have a stronger impact on measurement invariance than differences in factor means, with heterogeneity in latent variances more strongly affecting scalar invariance testing than metric invariance testing. Among model selection methods, goodness-of-fit indices generally exhibited lower power compared to likelihood ratio tests (LRTs), information criteria (ICs; except BIC), and leave-one-out cross-validation (LOO), which achieved a good balance between false and true positive rates. Full article
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17 pages, 15781 KiB  
Article
A Non-Parametric Test for a Two-Way Analysis of Variance
by Stefano Bonnini, Michela Borghesi, Gianfranco Piscopo and Massimiliano Giacalone
Mathematics 2025, 13(7), 1131; https://doi.org/10.3390/math13071131 - 29 Mar 2025
Viewed by 472
Abstract
The methodology carried out in this work is based on non-parametric inference. The problem is framed as a regression analysis, and the solution is derived using the permutation approach. The proposed test does not rely on the assumption that the distribution of the [...] Read more.
The methodology carried out in this work is based on non-parametric inference. The problem is framed as a regression analysis, and the solution is derived using the permutation approach. The proposed test does not rely on the assumption that the distribution of the response follows a specific family of probability laws, unlike other parametric approaches. This makes the test powerful, particularly when the typical assumptions of parametric approaches, such as the normality of data, are not satisfied and parametric tests are not reliable. Furthermore, this method is more flexible and robust with respect to parametric tests. A permutation test on the goodness-of-fit of a multiple regression model is applied. Hence, proposed solution consists of the application of permutation tests on the significance of the single coefficients and then a combined permutation test (CPT) to solve the overall goodness-of-fit testing problem. Furthermore, a Monte Carlo simulation study was performed to evaluate the power of the previously mentioned permutation approach, comparing it with the conventional parametric F-test for ANOVA and the bootstrap combined test, both commonly discussed in the literature on this statistical problem. Finally, the proposed non-parametric test was applied to real-world data to investigate the impact of age and smoking habits on medical insurance costs in the USA. The findings suggest that smoking and being at least 50 years old significantly contribute to increased medical insurance costs. Full article
(This article belongs to the Section D1: Probability and Statistics)
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16 pages, 1506 KiB  
Article
Estimation of Maximum Obtainable RBE ‘Turnover-Points’ (LETU) for Accelerated Ions Based on a Nuclear Charge Radius Hypothesis to Obtain Iso-Effective LET and RBE Values
by Bleddyn Jones
Biophysica 2025, 5(1), 6; https://doi.org/10.3390/biophysica5010006 - 25 Feb 2025
Viewed by 912
Abstract
Purpose: The purpose of this study is to analyze the relationship between nuclear charge (Z), atomic mass (A), LET (linear energy transfer for maximal relative biological effectiveness (RBE)) for accelerated ions based on the hypothesis that for each ion, LETU is related [...] Read more.
Purpose: The purpose of this study is to analyze the relationship between nuclear charge (Z), atomic mass (A), LET (linear energy transfer for maximal relative biological effectiveness (RBE)) for accelerated ions based on the hypothesis that for each ion, LETU is related to their nuclear radius. Methods: Published LETU data for proton, helium, carbon, neon, silicon, argon, and iron ions and their Z and A numbers are fitted by a power law function (PLF) and compared with PLF based on atomic cross-sections and nuclear dimensions for spherical or spheroidal atomic nuclei. The PLF allows for isoeffective RBE estimations for different ions at any value of LET based on the LETU estimations. For any two ions, A and B, and a specified bioeffect obtained at LETA, the equivalent isoeffective LETB, is estimated using LETB=LETA.LETU[B]LETU[A]. Results: The data-fitting program provided the following results: LETU=78.1.A0.26, and LETU=86.6.Z0.29, where 78.1 and 86.6 keV.μm−1 are the proton LETU values (i.e., without proton cellular range limit considerations). Goodness-of-fit tests are similar for each model, but the proton estimations differ. These exponents are lower than 0.66 and 0.33 (those for nuclear cross-sections and spherical nuclear radii, respectively), but suggest prolate nuclear shapes in most of the ions studied. Worked examples of estimating isoeffective LET values for two different ions are provided. Conclusions: The fitted power law relationships between LETU and Z or A are broadly equivalent and compatible with prolate nuclear shapes. These models may offer a more rational basis for future ion-beam radiobiology research. Full article
(This article belongs to the Collection Feature Papers in Biophysics)
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34 pages, 37538 KiB  
Article
Beyond Correlation to Causation in Hunter–Gatherer Ritual Landscapes: Testing an Ontological Model of Site Locations in the Mojave Desert, California
by David S. Whitley, JD Lancaster and Andrea Catacora
Arts 2025, 14(1), 20; https://doi.org/10.3390/arts14010020 - 18 Feb 2025
Cited by 3 | Viewed by 1721
Abstract
Why are rock art sites found in certain places and not others? Can locational or environmental variables inform an understanding of the function and meaning of the art? How can we move beyond observed patterning in spatial associations to a credible explanation of [...] Read more.
Why are rock art sites found in certain places and not others? Can locational or environmental variables inform an understanding of the function and meaning of the art? How can we move beyond observed patterning in spatial associations to a credible explanation of such meanings and ensure that we are not confusing correlation with causation? And what variables were most relevant in influencing site locational choices? These and related problems, whether recognized or not, are the subtext of the last three decades of rock art site distributional and landscape studies. They are now especially important to resolve given the need for accurate predictive modeling due to the rapid transformation of certain regions from undeveloped rural areas into rural industrial landscapes. Partly with this problem in mind, Whitley developed a descriptive model that provides an explanation for the location of Native Californian rock art in the Mojave Desert. It identifies the variables most relevant to site locations based on ethnographic Indigenous ontological beliefs about the landscape. These concern the geographical distribution of supernatural power and its association with certain landforms, natural phenomena and cultural features. His analysis further demonstrated that this model can account for two unusually large concentrations of sites and motifs: the Coso Range petroglyphs and the Carrizo Plain pictographs. But unanswered was the question of whether the model is applicable more widely, especially to smaller sites and localities made by different cultural groups. We documented and analyzed three petroglyph localities with seven small petroglyph sites in the southern Mojave Desert, California, to test this model. These sites are attributed to the Takic-speaking Cahuilla and Serrano tribes. Our study revealed a good fit between the expected natural and cultural variables associated with rock art site locations, with the number of such variables present at any given locale potentially correlated with the size of the individual sites. In addition to the research value of these results, this suggests that the model may be useful in the predictive modeling of rock art site locations for heritage management purposes. Full article
(This article belongs to the Special Issue Advances in Rock Art Studies)
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13 pages, 1621 KiB  
Article
Development and Validation of a Quantitative Score for the Criteria Clinical Control in Stable COPD Proposed in the Spanish COPD Guidelines (GesEPOC): Results of the EPOCONSUL Audit
by Myriam Calle Rubio, Juan José Soler Cataluña, Marc Miravitlles, Bernardino Alcázar Navarrete, José Luis López-Campos, Manuel E. Fuentes Ferrer and Juan Luis Rodríguez Hermosa
J. Clin. Med. 2025, 14(3), 707; https://doi.org/10.3390/jcm14030707 - 22 Jan 2025
Cited by 1 | Viewed by 1129
Abstract
Introduction/Objective: the concept of clinical control of COPD is a measure proposed in the Spanish COPD Guidelines (GesEPOC), which aims to help clinicians assess the clinical status in order to adapt the treatment plan at follow-up. However, studies that have evaluated clinical [...] Read more.
Introduction/Objective: the concept of clinical control of COPD is a measure proposed in the Spanish COPD Guidelines (GesEPOC), which aims to help clinicians assess the clinical status in order to adapt the treatment plan at follow-up. However, studies that have evaluated clinical practice reveal that the degree of control of COPD is not always assessed, which underlines the need to promote its assessment through a scoring system. To develop a scoring system that quantitatively assesses the validated criteria defining the degree of COPD control. Methods: this study used data from the EPOCONSUL audit in respiratory clinics across Spain. We included in this analysis all patients with a COPD clinical control grade estimated and reported by the physician at the visit, who had registered the criteria necessary to define the degree of clinical control validated and established in GesEPOC. Patients were randomly assigned to either the development or validation cohorts. The development cohort included 485 patients and the validation cohort included 341 patients. Score modelling was conducted using a multivariate logistic regression model, and calibration of the model and score was assessed using the Hosmer-Lemeshow goodness-of-fit test and GiViTi Calibration belts. The model and generated score’s discrimination capacity were analyzed by calculating the Area Under the Curve (AUC). Results: the scoring system was developed using four criteria as predictors of poor clinical control of COPD reported by the treating physician:adjusted dyspnoea severity, use of rescue inhaler more than three times per week, walking less than 30 min per day, and COPD exacerbations in the last three months. The scoring system attributed scores from 0 to 8. Calibration was satisfactory in both development and validation cohorts, and the score’s discrimination power, as indicated by the AUC, was 0.892. Conclusions: this scoring system provides an easy-to-use quantitative assessment of clinical control of COPD that we believe will help to measure COPD control and its evolution during patient follow-up. Future research will be needed to prospectively evaluate this score as a predictor of outcome. Full article
(This article belongs to the Section Respiratory Medicine)
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30 pages, 775 KiB  
Article
Goodness-of-Fit Test for the Bivariate Negative Binomial Distribution
by Francisco Novoa-Muñoz and Juan Pablo Aguirre-González
Axioms 2025, 14(1), 54; https://doi.org/10.3390/axioms14010054 - 12 Jan 2025
Viewed by 795
Abstract
When modeling real-world data, we face the challenge of determining which probability distribution best represents the data. To address this intricate problem, we rely on goodness-of-fit tests. However, when the data come from a bivariate negative binomial distribution, the literature reveals no existing [...] Read more.
When modeling real-world data, we face the challenge of determining which probability distribution best represents the data. To address this intricate problem, we rely on goodness-of-fit tests. However, when the data come from a bivariate negative binomial distribution, the literature reveals no existing goodness-of-fit test for this distribution. For this reason, in this article, we propose and study a computationally convenient goodness-of-fit test for the bivariate negative binomial distribution. This test is based on a bootstrap approximation and a parallelization strategy. To this end, we use a reparameterization technique based on the probability generating function and a Cramér-von Mises-type statistic. From the simulation studies, we conclude that the results converge to the established nominal levels as the sample size increases, and in all cases considered, the parametric bootstrap method provides an accurate approximation of the null distribution of the statistic we propose. Additionally, we verify the power of the proposed test, as well as its application to five real datasets. To accelerate the massive computational work, we employ the parallelization strategy that, according to Novoa-Muñoz (2024), was the most efficient among the techniques he analyzed. Full article
(This article belongs to the Special Issue Advances in Statistical Simulation and Computing)
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14 pages, 11430 KiB  
Article
Testing the Validity of the Montgomery–Koyama–Smith Equation for Calculating the Total Petal Area per Flower Using Two Rosaceae Species
by Chuanlong Zhao, Jinfeng Wang, Youying Mu, Weihao Yao, Hui Wang and Peijian Shi
Plants 2024, 13(24), 3499; https://doi.org/10.3390/plants13243499 - 15 Dec 2024
Cited by 3 | Viewed by 841
Abstract
The size of floral organs is closely related to the successful reproduction of plants, and corolla size is, to some extent, indicative of the size of floral organs. Petals are considered to be homologous to leaves, so we also attempted to estimate the [...] Read more.
The size of floral organs is closely related to the successful reproduction of plants, and corolla size is, to some extent, indicative of the size of floral organs. Petals are considered to be homologous to leaves, so we also attempted to estimate the area of a single petal using the method that is typically employed for estimating single leaf area (i.e., the Montgomery equation). Additionally, we estimated the total petal area per flower (AT; i.e., the whole corolla area) using the method designed for estimating the total leaf area per shoot (i.e., the Montgomery–Koyama–Smith equation). The Montgomery equation (ME) estimates the leaf area by assuming that the leaf area is proportional to the product of leaf length and width. The Montgomery–Koyama–Smith equation (MKSE) assumes that the total leaf area per shoot is proportional to the product of the sum of individual leaf widths and the maximum individual leaf length. To test the validity of the ME for predicting petal area, a total of 1005 petals from 123 flowers of two Rosaceae species, which exhibit a certain variation in petal shape, were used to fit the relationship between the petal area (A) and the product of petal length (L) and width (W). Two equations, including the MKSE and a power-law equation (PLE), were used to describe the relationship between the total petal area per flower and the product of the sum of individual petal widths and the maximum individual petal length. The root-mean-square error (RMSE) and the Akaike information criterion (AIC) were used to measure the goodness of fit and the trade-off between the goodness of fit and model’s structural complexity for each equation. The results show that the ME has a low RMSE value and a high correlation coefficient when fitting the relationship between A and LW for either of the two species. Additionally, the MKSE and the PLE exhibit low RMSEs and AICs for estimating the AT of both Rosaceae species. These results indicate that the ME, MKSE, and PLE are effective in predicting individual petal area and total corolla area, respectively. Full article
(This article belongs to the Section Plant Modeling)
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