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Foam rolling and stretching do not provide superior acute flexibility and stiffness improvements compared to any other w.rm-up intervention: A systematic review.w.th meta-analysis

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Journal of Sport and Health Science 2024年第4期13卷 509-520页

作者： Konstantin w.rneke Gerit Plöschberger Lars H.Lohmann Eric Lichtenstein Daniel jochum Stanislav D.Siegel Astrid Zech David G.Behm Institute of Sport Science University of KlagenfurtKlagenfurt am Wörthersee 9020Austria Department of Human Motion Science and Exercise Physiology Friedrich Schiller UniversityJena 07749Germany Department Sport Exercise and HealthUniversity of BaselBasel 4052Switzerland Department of Health Sciences and Technology ETH ZurichZurich 8092Switzerland School of Human Kinetics and Recreation Memorial University of NewfoundlandSt.JohnsNL A1C 5S7Canada

Background:Acute improvement in range of motion(ROM)is a w.dely reported effect of stretching and foam rolling,w.ich is commonly explained by changes in pain threshold and/or musculotendinous ***,these effects w.re also reported in response to various other active and passive interventions that induce responses such as enhanced muscle ***,w. hypothesized that acute ROM enhancements could be induced by a w.de variety of interventions other than stretching or foam rolling that promote an increase in muscle ***:After a systematic search in PubMed,w.b of Science,and SPORTDiscus databases,38 studies comparing the effects of stretching and foam rolling w.th several other interventions on ROM and passive properties w.re *** studies had 1134 participants in total,and the data analysis resulted in 140 effect sizes(ESs).ES calculations w.re performed using robust variance estimation model w.th ***:Study quality of the included studies w.s classified as fair(PEDro score=4.58)w.th low.to moderate certainty of *** show.d no significant differences in ROM(ES=0.01,p=0.88),stiffness(ES=0.09,p=0.67),or passive peak torque(ES=-0.30,p=0.14)betw.en stretching or foam rolling and the other identified *** plots revealed no publication ***:Based on current literature,our results challenge the established view.on stretching and foam rolling as a recommended component of w.rm-up *** lack of significant difference betw.en interventions suggests there is no need to emphasize stretching or foam rolling to induce acute ROM,passive peak torque increases,or stiffness reductions.

关键词： Range of motion Passive properties Muscletendon unit Muscle tissue

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Application of ACP Nonlinear Math in Analyzing Arithmetic and Radiation Transmission Data (Application 1 & 2) [4-21-2024, 820P] (V)

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Journal of Applied Mathematics and Physics 2024年第6期12卷 2302-2319页

作者： Ralph w. Lai Melisa w. Lai-Becker Grace Cheng-Dodge 28 Cornerstone Ct. Doylestown PA USA Harvard Medical School Cambridge MA USA Independent Education Consultants West Hartford CT USA

In this study, w. explore the application of ACP (asymptotic curve based and proportionality oriented) Alpha Beta (αβ) Nonlinear Math to analyze arithmetic and radiation transmission data. Specifically, w. investigate the relationship betw.en tw. variables. The novel approach involves collecting elementary “y” data and subsequently analyzing the asymptotic cumulative or demulative (opposite of cumulative) Y data. In part I, w. examine the connection betw.en the common linear numbers and ideal nonlinear numbers. In part II, w. delve into the relationship betw.en X-ray energy and the radiation transmission for various thin film materials. The fundamental physical law.asserts that the nonlinear change in continuous variable Y is negatively proportional to the nonlinear change in continuous variable X, expressed mathematically as dα = −Kdβ. Here: dα {Y, Yu, Yb} represents the change in Y, w.th Yu and Yb denoting the upper and baseline asymptote of Y. dβ {X, Xu, Xb} represents the change in X, w.th Xu and Xb denoting the upper and baseline asymptote of X. K represents the proportionality constant or rate constant, w.ich varies based on equation arrangement. K is the key inferential factor for describing physical phenomena.

关键词： Asymptotic Concave and Convex Curve Upper and Baseline Asymptote Demulative vs. Cumulative Coefficient of Determination Proportionalityand Position Constant Skew.d Bell and Sigmoid Curve

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Characterization and Modeling of Mechanical Properties of Additively Manufactured Coconut Fiber-Reinforced Polypropylene Composites

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Advances in Materials Physics and Chemistry 2024年第6期14卷 95-112页

作者： George Mosi Bernard w. Ikua Samuel K. Kabini James w. Mw.ngi Department of Mechatronic Engineering Jomo Kenyatta University of Agriculture and Technology Juja Kenya

In the face of the increased global campaign to minimize the emission of greenhouse gases and the need for sustainability in manufacturing, there is a great deal of research focusing on environmentally benign and renew.ble materials as a substitute for synthetic and petroleum-based products. Natural fiber-reinforced polymeric composites have recently been proposed as a viable alternative to synthetic materials. The current w.rk investigates the suitability of coconut fiber-reinforced polypropylene as a structural material. The coconut fiber-reinforced polypropylene composites w.re developed. Samples of coconut fiber/polypropylene (PP) composites w.re prepared using Fused Filament Fabrication (FFF). Tests w.re then conducted on the mechanical properties of the composites for different proportions of coconut fibers. The results obtained indicate that the composites loaded w.th 2 w.% exhibited the highest tensile and flexural strength, w.ile the ones loaded w.th 3 w.% had the highest compression strength. The ultimate tensile and flexural strength at 2 w.% w.re determined to be 34.13 MPa and 70.47 MPa respectively. The compression strength at 3 w.% w.s found to be 37.88 MPa. Compared to pure polypropylene, the addition of coconut fibers increased the tensile, flexural, and compression strength of the composite. In the study, an artificial neural netw.rk model w.s proposed to predict the mechanical properties of polymeric composites based on the proportion of fibers. The model w.s found to predict data w.th high accuracy.

关键词： Additive Manufacturing Artificial Neural Netw.rk Mechanical Properties Natural Fibers Polypropylene

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Sim-to-Real: A Performance Comparison of PPO, TD3, and SAC Reinforcement Learning Algorithms for Quadruped w.lking Gait Generation

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Journal of Intelligent Learning Systems and Applications 2024年第2期16卷 23-43页

作者： James w. Mock Suresh S. Muknahallipatna Department of Electrical Engineering and Computer Science University of Wyoming Laramie WY USA

The performance of the state-of-the-art Deep Reinforcement algorithms such as Proximal Policy Optimization, Tw.n Delayed Deep Deterministic Policy Gradient, and Soft Actor-Critic for generating a quadruped w.lking gait in a virtual environment w.s presented in previous research w.rk titled “A Comparison of PPO, TD3, and SAC Reinforcement Algorithms for Quadruped w.lking Gait Generation”. w. demonstrated that the Soft Actor-Critic Reinforcement algorithm had the best performance generating the w.lking gait for a quadruped in certain instances of sensor configurations in the virtual environment. In this w.rk, w. present the performance analysis of the state-of-the-art Deep Reinforcement algorithms above for quadruped w.lking gait generation in a physical environment. The performance is determined in the physical environment by transfer learning augmented by real-time reinforcement learning for gait generation on a physical quadruped. The performance is analyzed on a quadruped equipped w.th a range of sensors such as position tracking using a stereo camera, contact sensing of each of the robot legs through force resistive sensors, and proprioceptive information of the robot body and legs using nine inertial measurement units. The performance comparison is presented using the metrics associated w.th the w.lking gait: average forw.rd velocity (m/s), average forw.rd velocity variance, average lateral velocity (m/s), average lateral velocity variance, and quaternion root mean square deviation. The strengths and w.aknesses of each algorithm for the given task on the physical quadruped are discussed.

关键词： Reinforcement Learning Reality Gap Position Tracking Action Spaces Domain Randomization

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Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

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w.rld Journal of Engineering and Technology 2024年第1期12卷 117-140页

作者： Soham S. Bahulekar Alberto w. Mello Embry-Riddle Aeronautical University Daytona Beach Florida USA

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and w.ter, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research w.re simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in w.ter resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

关键词： Seaplane Spray Rails Hull Optimization Take-Off Performance

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综述杂豆酚类化合物多样性的影响因素

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中国食品学报 2024年第1期24卷 390-406页

作者：李昱昊宋萧萧聂少平 Cui Steve w. 谢明勇殷军艺南昌大学食品科学与资源挖掘全国重点实验室中国-加拿大食品科学与技术联合实验室(南昌)江西省生物活性多糖重点实验室南昌330047 加拿大农业与农业食品部圭尔夫食品研究中心加拿大安大略NIG5C9

杂豆酚类化合物种类繁多,并影响杂豆的外观、感官特征及营养特性。杂豆酚类化合物多样性是杂豆营养特性研究的重点。本文总结杂豆酚类化合物多样性的影响因素,发现合理的提取与分析方法有利于酚类化合物提取的完整性以及表征的正确性。... 详细信息

杂豆酚类化合物种类繁多,并影响杂豆的外观、感官特征及营养特性。杂豆酚类化合物多样性是杂豆营养特性研究的重点。本文总结杂豆酚类化合物多样性的影响因素,发现合理的提取与分析方法有利于酚类化合物提取的完整性以及表征的正确性。在此基础上,指出种属与产地、生长与贮藏及加工过程影响杂豆酚类化合物的合成、溶出与释放,并促使酚类化合物多样性的形成。最后介绍杂豆酚类化合物多样性的代谢组学技术在杂豆多样性研究方面的贡献与优势,提出今后工作的重点与挑战,以期为杂豆酚类化合物的变化机制、加工利用及育种等提供参考。

关键词：杂豆酚类化合物多样性提取方法定性与定量影响因素

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Gas Exchange Rates of Texas Persimmon (Diospyros texana) in Central Texas w.odlands

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American Journal of Plant Sciences 2024年第5期15卷 329-348页

作者： Matthew.B. Grunstra Oscar w. Van Auken Department of Integrative Biology University of Texas at San Antonio San Antonio TX USA

Diospyros texana (Texas persimmon) is a secondary species in most Juniperus ashei/Quercus fusiformis w.odlands in central Texas. It has high density, but plants are mostly in the community understory. Light response curves at ambient and elevated levels of CO2 and temperature w.re measured for D. texana. The Anet (photosynthetic rate) increased significantly as both light level and CO2 levels increased but not temperature. The Amax (maximum photosynthetic rate) of D. texana in full sun at elevated levels of CO2 w.s increased for all treatments. Stomatal conductance increased w.th levels of CO2 but only if the interaction w.s removed from the model. Intercellular levels of CO2 increased w.th both temperature and CO2 treatments as did w.ter use efficiency (w.E). Furthermore, light saturation (Lsat) increased w.th CO2 treatments and light compensation (Lcp) increased w.th temperature. The dark respiration (Rd) increased w.th both temperature and CO2 treatments. Markov population models suggested D. texana populations w.uld remain ecologically similar in the future. How.ver, sub-canopy light levels and herbivory should be considered w.en examining population projections. For example, Juniperus ashei juveniles are not recruited into any canopy unless there are high light levels. Herbivory reduces the success of Quercus juveniles from reaching the canopy. These factors do not seem to be a problem for D. texana juveniles w.ich w.uld allow.them to reach the canopy w.thout need of a high light gap and are not prevented by herbivory. Thus, Juniperus/Quercus w.odlands w.ll change in the future to w.odlands w.th D. texana a more common species.

关键词： Replacement Dynamics Ecological Succession CO2 Concentrations Temperature Levels Photosynthetic Rates Drought Tolerance Herbivory Species Replacement Encroachment Juniper

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教育的未来:从“学会成长”到“新的社会契约”∗———访UNESCO《一起重新构想我们的未来》报告起草者诺亚·w.索贝教授

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全球教育展望 2024年第7期53卷 3-12页

作者：于金申诺亚·w.索贝华东师范大学教育学部教育学系上海200062 芝加哥洛约拉大学历史学系芝加哥60660

作为联合国教科文组织《一起重新构想我们的未来:为教育打造新的社会契约》报告的重要起草者之一,诺亚·w.索贝教授基于其学术研究和参与报告起草的经历,分享了自己的独特见解。他认为,这份报告建立在三地平线框架、变化理论、未来素养... 详细信息

作为联合国教科文组织《一起重新构想我们的未来:为教育打造新的社会契约》报告的重要起草者之一,诺亚·w.索贝教授基于其学术研究和参与报告起草的经历,分享了自己的独特见解。他认为,这份报告建立在三地平线框架、变化理论、未来素养、渴望能力、涌现思想等坚实的学理基础之上。在报告的内容层面,“新的社会契约”理念体现了民主参与式的教育转型思路,其实现过程需要因地制宜、灵活应变,并需不断地迭代与完善。未来学校将呈现复数形态,成为新兴的、充满创造力的、开放式的代际交流场所。就当前的学术争论而言,该报告展现了一种修复未来的政治立场,但在如何凸显教育的“弱”、展现教与学的不确定性特质,以及探索国际教育合作的具体路径方面,仍存在一定的提升空间。

关键词：联合国教科文组织教育社会契约学会成长未来教育未来学校

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Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong S.w.Lee w.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)w.th a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,w.re examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy w.s achieved by employing high-ratio differential speed *** best superplasticity w.s achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),w.ere tensile elongations of 550±600%w.re *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size w.s observed at temperatures above 573 ***,it w.s important to consider this effect w.en analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow.at low.strain rates w.s governed by lattice diffusion-controlled grain boundary sliding,w.ile at high strain rates,lattice diffusion-controlled dislocation climb creep w.s the rate-controlling deformation *** w.s concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it w.s observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps w.re constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain grow.h

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The Effects of the Longitudinal Axis of Loading upon Bending, Shear and Torsion of a Thin-w.lled Cantilever Channel Beam

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w.rld Journal of Mechanics 2024年第5期14卷 73-96页

作者： David w. A. Rees Abdelraouf M. Sami Alsheikh College of Engineering and Design Brunel University Uxbridge UK

Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers w.th x-axis symmetry. The flexural bending and shear that arise w.th applied axial torsion are each considered theoretically and numerically in terms of tw. longitudinal axes of loading not coincident w.th the shear centre. In particular, the w.rping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its w.b centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam w.en loading is referred to a flexural axis through the shear centre. w.thin the net stress analysis is, it is show. how.the constraint to free w.rping presented by the end fixing modifies the axial stress. The latter can be identified w.th the action of a ‘bimoment’ upon each thin-w.lled section.

关键词： Thin-Aluminium Channels Cantilever Beam Bending Shear Torsion w.rping Bimoment Flexural Axis Centre of Tw.st Centroid Shear Centre Torsional Stiffness Constrained Stress

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