Neuromechanical Patterns Underlying Chronic Ankle Instability

Lateral ankle sprain is one of the most common musculoskeletal injuries among physically active populations. Chronic ankle instability (CAI) can develop following a substantial ankle sprain and has a high prevalence rate. CAI is a complex and multifactorial condition arising from a range of neuromechanical impairments. However, the contributing factors to the development of CAI are poorly understood due to conflicting results of the previous research influenced by the variations in movement tasks and definitions of the CAI condition, and limited evidence on the dynamic interaction between lower limb neuromechanical parameters during functional activities. This thesis aimed to identify lower limb biomechanical alterations during dynamic tasks and to explore the neuromuscular components of peroneal muscles in individuals with CAI compared to a healthy control group. Three experimental studies with thirty-two participants (17 CAI and 15 controls) were conducted to identify lower limb biomechanical alterations associated with CAI. Sagittal and frontal plane ankle and hip joint angles and moments, and mediolateral foot balance (MLFB) were calculated during walking, running and lateral jump-landing tasks. In addition, a systematic review with meta-analysis has been carried out to synthesise research on neuromuscular characteristics of peroneal muscles, including corticospinal excitability, strength, proprioception (force sense) and electromyographic measures in individuals with CAI compared to healthy controls. During the walking task, no significant between-group differences were observed for the research variables including ankle kinematics, ankle and hip moments, and MLFB. During the running, the individuals with CAI exhibited a significantly greater peak plantar flexion angle (p = 0.022) during early stance, lower plantar flexor moment (p < 0.001) including a reduced peak plantar flexor moment (p = 0.002), as well as more laterally deviated MLFB (p = 0.014) than the control group throughout the midstance phase. Hip moments were not significantly different between the groups during the running task. In the jump-landing, the CAI group demonstrated a greater peak hip adduction angle (p = 0.039) and greater hip extensor moment (p = 0.008) in the early phase of the ground contact compared to the control group. No intergroup differences were found in ankle joint kinematics or moments, or in MLFB during the jump-landing task. Among 13,670 studies retrieved, 42 were included in the systematic review, with 25 eligible for meta-analysis, revealing significantly less isometric evertor force sense accuracy and prolonged peroneus longus latency during single leg landing inversion perturbation test under unexpected conditions in individuals with CAI than the control group. These findings may suggest potential neuromechanical dysfunctions in the sensorimotor system underlying the mechanisms that characterise CAI, providing insight into the complexity and multifaceted nature of the issue and helping to inform the optimisation of future intervention designs

High-order harmonic generation from Rydberg states at fixed Keldysh parameter

Because the commonly adopted viewpoint that the Keldysh parameter $\gamma$ determines the dynamical regime in strong field physics has long been demonstrated to be misleading, one can ask what happens as relevant physical parameters, such as laser intensity and frequency, are varied while $\gamma$ is kept fixed. We present results from our one- and fully three-dimensional quantum simulations of high-order harmonic generation (HHG) from various bound states of hydrogen with $n$ up to 40, where the laser intensities and the frequencies are scaled from those for $n=1$ in order to maintain a fixed Keldysh parameter $\gamma$$< 1$ for all $n$. We find that as we increase $n$ while keeping $\gamma$ fixed, the position of the cut-off scales in well defined manner. Moreover, a secondary plateau forms with a new cut-off, splitting the HHG plateau into two regions. First of these sub-plateaus is composed of lower harmonics, and has a higher yield than the second one. The latter extends up to the semiclassical $I_p+3.17U_p$ cut-off. We find that this structure is universal, and the HHG spectra look the same for all $n\gtrsim 10$ when plotted as a function of the scaled harmonic order. We investigate the $n$-, $l$- and momentum distributions to elucidate the physical mechanism leading to this universal structure

Phase-dependent interference fringes in the wavelength scaling of harmonic efficiency

We describe phase-dependent wavelength scaling of high-order harmonic generation efficiency driven by ultra-short laser fields in the mid-infrared. We employ both numerical solution of the time-dependent Schr\"{o}dinger equation and the Strong Field Approximation to analyze the fine-scale oscillations in the harmonic yield in the context of channel-closing effects. We show, by varying the carrier-envelope phase, that the amplitude of these oscillations depend strongly on the number of returning electron trajectories. Furthermore, the peak positions of the oscillations vary significantly as a function of the carrier-envelope phase. Owing to its practical applications, we also study the wavelength dependence of harmonic yield in the "single-cycle" limit, and observe a smooth variation in the wavelength scaling originating from the vanishing fine-scale oscillations.Comment: 5 pages, 4 figure

A local version of the Pawlucki-Plesniak extension operator

Cataloged from PDF version of article.Using local interpolation of Whitney functions, we generalize the Pawłucki and Pleśniak approach to construct a continuous linear extension operator. We show the continuity of the modified operator in the case of generalized Cantor-type sets without Markov's Property. © 2004 Elsevier Inc. All rights reserved

Dielectronic Recombination of Fe XV forming Fe XIV: Laboratory Measurements and Theoretical Calculations

We have measured resonance strengths and energies for dielectronic recombination (DR) of Mg-like Fe XV forming Al-like Fe XIV via N=3 -> N' = 3 core excitations in the electron-ion collision energy range 0-45 eV. All measurements were carried out using the heavy-ion Test Storage Ring at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We have also carried out new multiconfiguration Breit-Pauli (MCBP) calculations using the AUTOSTRUCTURE code. For electron-ion collision energies < 25 eV we find poor agreement between our experimental and theoretical resonance energies and strengths. From 25 to 42 eV we find good agreement between the two for resonance energies. But in this energy range the theoretical resonance strengths are ~ 31% larger than the experimental results. This is larger than our estimated total experimental uncertainty in this energy range of +/- 26% (at a 90% confidence level). Above 42 eV the difference in the shape between the calculated and measured 3s3p(^1P_1)nl DR series limit we attribute partly to the nl dependence of the detection probabilities of high Rydberg states in the experiment. We have used our measurements, supplemented by our AUTOSTRUCTURE calculations, to produce a Maxwellian-averaged 3 -> 3 DR rate coefficient for Fe XV forming Fe XIV. The resulting rate coefficient is estimated to be accurate to better than +/- 29% (at a 90% confidence level) for k_BT_e > 1 eV. At temperatures of k_BT_e ~ 2.5-15 eV, where Fe XV is predicted to form in photoionized plasmas, significant discrepancies are found between our experimentally-derived rate coefficient and previously published theoretical results. Our new MCBP plasma rate coefficient is 19-28% smaller than our experimental results over this temperature range

Aggregation operators of complex fuzzy Z-number sets and their applications in multi-criteria decision making

Fuzzy sets (FSs) are a flexible and powerful tool for reasoning about uncertain situations that cannot be adequately expressed by classical sets. However, these sets fall short in two areas. The first is the reliability of this tool. Z-numbers are an extension of fuzzy numbers that improve the representation of uncertainty by combining two important components: restriction and reliability. The second is the problems that need to be solved simultaneously. Complex fuzzy sets (CFSs) overcome this problem by adding a second dimension to fuzzy numbers and simultaneously adding connected elements to the solution. However, they are insufficient when it comes to problems involving these two areas. We cannot express real-life problems that need to be solved at the same time and require the reliability of the information given with any set approach given in the literature. Therefore, in this study, we propose the complex fuzzy Z-number set (CFZNS), a generalization of Z-numbers and CFS, which fills this gap. We provide the operational laws of CFZNS along with some properties. Additionally, we define two essential aggregation operators called complex fuzzy Z-number weighted averaging (CFZNWA) and complex fuzzy Z-number weighted geometric (CFZNWG) operators. Then, we present an illustrative example to demonstrate the proficiency and superiority of the proposed approach. Thus, we process multiple fuzzy expressions simultaneously and take into account the reliability of these fuzzy expressions in applications. Furthermore, we compare the results with the existing set operations to confirm the advantages and demonstrate the efficiency of the proposed approach. Considering the simultaneous expression of fuzzy statements, this study can serve as a foundation for new aggregation operators and decision-making problems and can be extended to many new applications such as pattern recognition and clustering

A fixed point theorem for multi-maps satisfying an implicit relation on metrically convex metric spaces

In this paper, we give a fixed point theorem for multi-valued mapping satisfying an implicit relation on metrically convex metric spaces. This result extends and generalizes some fixed point theorem in the literature

Improved chemotaxis differential evolution optimization algorithm

The social foraging behavior of Escherichia coli has recently received great attention and it has been employed to solve complex search optimization problems.This paper presents a modified bacterial foraging optimization BFO algorithm, ICDEOA (Improved Chemotaxis Differential Evolution Optimization Algorithm), to cope with premature convergence of reproduction operator.In ICDEOA, reproduction operator of BFOA is replaced with probabilistic reposition operator to enhance the intensification and the diversification of the search space.ICDEOA was compared with state-of-the-art DE and non-DE variants on 7 numerical functions of the 2014 Congress on Evolutionary Computation (CEC 2014). Simulation results of CEC 2014 benchmark functions reveal that ICDEOA performs better than that of competitors in terms of the quality of the final solution for high dimensional problems