Kinematic Variables Research Articles

Head Kinematics Associated with Off-Field Head Injury Assessment (HIA1) Events in a Season of English Elite-Level Club Men's and Women's Rugby Union Matches.

The purpose of this study was to investigate head kinematic variables in elite men's and women's rugby union and their ability to predict player removal for an off-field (HIA1) head injury assessment. Instrumented mouthguard (iMG) data were collected for 250 men and 132 women from 1865 and 807 player-matches, respectively, and synchronised to video-coded match footage. Head peak resultant linear acceleration (PLA), peak resultant angular acceleration (PAA) and peak change in angular velocity (dPAV) were extracted from each head acceleration event (HAE). HAEs were linked to documented HIA1 events, with ten logistical regression models for men and women, using a random subset of non-case HAEs, calculated to identify kinematic variables associated with HIA1 events. Receiver operating characteristic curves (ROC) were used to describe thresholds for HIA1 removal. Increases in PLA and dPAV were significantly associated with an increasing likelihood of HIA1 removal in the men's game, with an OR ranging from 1.05-1.12 and 1.13-1.18, respectively. The optimal values to maximise for both sensitivity and specificity for detecting an HIA1 were 1.96krad⋅s-2, 24.29 g and 14.75 rad⋅s-1 for PAA, PLA and dPAV, respectively. Only one model had any significant variable associated with increasing the likelihood of a HIA1 removal in the women's game-PAA with an OR of 8.51 (1.23-58.66). The optimal values for sensitivity and specificity for women were 2.01 krad⋅s-2, 25.98 g and 15.38rad⋅s-1 for PAA, PLA and dPAV, respectively. PLA and dPAV were predictive of men's HIA1 events. Further HIA1 data are needed to understand the role of head kinematic variables in the women's game. The calculated spectrum of sensitivity and specificity of iMG alerts for HIA1 removals in men and women present a starting point for further discussion about using iMGs as an additional trigger in the existing HIA process.

Acute effects of different loading protocols upon performance and kinematics of 180 degrees change of direction

ABSTRACT This study examined the acute effects of different loading protocols on 180° change of direction (COD) performance in eleven male handball players. Participants performed a 10-0-5 COD test under seven conditions: without an external load, and with 3, 6, and 9 kg loads applied under two modes—assisted into the COD and resisted out of it and resisted into the COD and assisted out of it. While total COD time was not affected (p = 0.098; η2 = 0.16), significant phase effects were observed (p < 0.001; η2 ≥ 0.55). Loading protocols significantly influenced velocity, acceleration, and their distances from COD (p < 0.001; η2 ≥ 0.37). Significant phase effects were observed for all step kinematic variables (p ≤ 0.037; η2 ≥ 0.67), except contact time, and significant interaction (phase*condition) effects for all variables (p ≤ 0.004; η2 ≥ 0.08), except for step frequency. Assisted-resisted protocols increased deceleration demands through higher COD entry velocities, displaying fewer but longer steps in the acceleration phase and greater steps taken during the deceleration phase. Resisted-assisted protocols decreased deceleration demands due to lower COD entry velocities, displaying shorter, but more steps taken in the acceleration phase, and fewer steps taken in the deceleration phase. These findings suggest that assisted-resisted and resisted-assisted loading protocols can be used to selectively overload specific phases of COD performance.

Uncovering the structure and kinematics of the ionized core of M\,2-9 with ALMA

We present interferometric observations at 1 and 3\,mm with the Atacama Large Millimeter Array (ALMA) of the free-free continuum and millimeter(mm)-wavelength recombination line (mRRL) emission of the ionized core (within lsim 130\,au) of the young planetary nebula (PN) candidate M\,2-9. These inner regions are concealed in the vast majority of similar objects. A spectral index for the mm-to-centimeter(cm) continuum of sim 0.9 indicates predominantly free-free emission from an ionized wind, with a minor contribution from warm dust. The mm continuum emission in M\,2-9 reveals an elongated structure along the main symmetry axis of the large-scale bipolar nebula with a C-shaped curvature surrounded by a broad-waisted component. This structure is consistent with an ionized, bent jet and a perpendicular compact dusty disk. The presence of a compact equatorial disk (of radius sim 50\,au) is also supported by redshifted CO and absorption profiles observed from the base of the receding northern lobe against the compact background continuum. The redshift observed in the CO absorption profiles likely signifies gas infall movements from the disk toward a central source. The mRRLs exhibit velocity gradients along the axis, implying systematic expansion in the C-shaped bipolar outflow. The highest expansion velocities (sim 80\ are found in two diagonally opposed compact regions along the axis, referred to as the high-velocity spots or shells (HVSs), indicating either rapid wind acceleration or shocks at radial distances of sim 0 (sim 15-25\,au) from the center. A subtle velocity gradient perpendicular to the lobes is also found, suggesting rotation. Our ALMA observations detect increased brightness and broadness in the mRRLs compared to previously observed profiles, implying variations in wind kinematics and physical conditions on timescales of less than two years, which is in agreement with the extremely short kinematic ages (lsim 0.5-1\,yr) derived from observed velocity gradients in the compact ionized wind. Radiative transfer modeling indicates an average electron temperature of sim 15000\,K and reveals a nonuniform density structure within the ionized wind with electron densities ranging from to 10$^8$\ These results potentially reflect a complex bipolar structure resulting from the interaction of a tenuous companion-launched jet and the dense wind of the primary star.

3D limb dynamics of flyball dogs turning on different box angles.

There are no regulations for the flyball box angulation, which ranges from 45° to 89°. As such at present, the box turn is deemed to represent the greatest injury risk to competitors. The aim of this study was to understand the influence of box angle on kinematic variables during a flyball turn, by comparing dogs turning on three different angulations of flyball box (45°, 60° and 83°) to allow for recommendations to be made regarding the most appropriate box design in terms of limiting risk of injury across the sport, to increase both wellbeing and safety for competitors. Turning on a 45° box generates significantly more flexion in the forelimbs and carpus, whereas turning on an 83° box generates greater degrees of extension in the elbow, shoulder, hock and stifle. What our 3D analysis has shown is that the relationship between box angle and the physical demands placed on the dog are complex, and related mainly to asymmetrical nature of the sport, and as such no one angle may be more or less suitable for training and competition, but the 60° seems to be a mid-ground, whereas direction of turn may be fundamental in generating the potential for injury.

Pitching kinematics have direct and indirect effects on pitch location in NCAA baseball.

Kinematics and release parameters are important factors of throw location, yet an understanding of their relationship has yet to be achieved. This study sought to explore this relationship. Kinematic data were collected for seventy-seven collegiate pitchers. Fifty-seven kinematic parameters were included in path analyses for horizontal (HPL) and vertical plate locations (VPL). Release angles were set as mediating variables (MED) between independent (IV) and dependent (DV) variables. Eleven kinematic variables directly (13 indirectly) affected VPL, while 23 directly affected HPL (10 indirectly). Linear mixed models revealed that lateral trunk flexion at ball release (BR) (R2=.908, BIC=-598, ICC=.528) best explained VPL. Trunk flexion at foot contact (FC) (R2=.944, BIC=-607, ICC=.776), mediolateral centre of mass (COM) displacement at FC (R2=.974, BIC=-573, ICC=.918), and BR (R2=.967, BIC=-593, ICC=.865), and pelvis rotation at BR (R2=.965, BIC=-588, ICC=.895) models were identified for HPL. Results indicate the relationship between pitching kinematics, release conditions, and throw location is complex. Biomechanics can influence release parameters, which in turn impacts throw location. This work may serve to understand better how biomechanics influence performance.

Associations between less knee kinematic variability and worse patient-reported outcomes following anterior cruciate ligament reconstruction

ABSTRACT Individuals with anterior cruciate ligament reconstruction (ACLR) exhibit less knee kinematic variability while walking than uninjured controls, associated with deleterious changes in cartilage composition linked to an increased risk for early knee osteoarthritis (KOA). It is unknown whether less knee kinematic variability is also associated with worse knee-related patient-reported outcomes (PROs) consistent with KOA development. This study examined associations between kinematic variability during gait and PROs in individuals post-ACLR. Gait kinematics and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were collected from 45 participants 6-months post-ACLR (67% Females; 21.45 ± 4.56 years). Overground gait biomechanics using 3D motion capture were collected, and knee kinematics were extracted for post-processing. Sample entropy (SampEn) was used to calculate knee kinematic variability. Pearson’s product-moment correlations were conducted to determine the associations between SampEn and KOOS sub-scores. Additionally, independent samples t-tests were performed to evaluate potential differences in SampEn outcomes between individuals with and without clinically relevant symptoms (defined in the introduction). Less sagittal plane kinematic variability is associated with greater pain (r = 0.37, p = 0.01) and symptoms (r = 0.32, p = 0.03). Symptomatic participants demonstrated less sagittal plane knee kinematic variability compared to asymptomatic participants (p = 0.01). The findings suggest less variable gait patterns 6-months post-ACLR may be linked to KOA-related symptoms.

Exploring Kinematic Variations in Clear Hip Circle to Handstand: A Case Study of Performance Styles on Uneven Bars

(1) Background: This case study analyzed the successful performances of female gymnasts in the finals of the 39th and 40th World Cup in Maribor (SLO). The aim was to identify variations in their execution of the Clear Hip Circle to Handstand (CHCH) on uneven bars based on kinematic parameters. (2) Methods: This study involved elite female gymnasts from the 39th (n = 5, age: 17 ± 6 months) and 40th (n = 8, age: 17.5 ± 6 months) World Cups, totaling 13 gymnasts. Kinematic analysis was performed on 15 successful routines using the Ariel Performance Analysis System (Ariel Dynamics Inc., San Diego, CA). The analysis focused on 16 anthropometric reference points and 8 body segments, including the body mass center of gravity (CG). The main reference points analyzed were the hip joint, the shoulder joint, and the CG along the xy-axes. Trajectory, velocity, angle, and angular velocity of the hips and shoulders were calculated. Pearson correlation analysis was employed to assess the relationships between the kinematic variables. (3) Results: High intercorrelations between the reference points along the xy-axes (0.81–0.99) and optimal movement velocity were found. Dispersed results were observed for kinematic parameters of angle (0.10–0.16) and angular velocity of the hip joints (0.60–1.00), with similar dispersions for shoulder joints (0.51–1.00). Three distinct techniques were identified: (1) stretched body with minimal hip joint flexion throughout; (2) extended body with a short, quick hip joint extension during shoulder movement; and (3) hyperextension in the hip joint. (4) Conclusions: The kinematic analysis revealed three different performance styles of the CHCH among finalists. These variations in technique do not affect the success of the performance. This research contributes to a better understanding of the technique but does not prefer one style over another.

Exploring healthy knee kinematic phenotypes obtained through dynamic CT imaging: A cluster analysis study

Dynamic Computed Tomography (CT) emerges as a pivotal imaging modality for the assessment of knee joint kinematics. However, integrating dynamic CT into clinical practice necessitates a thorough understanding of healthy knee kinematics, as large variation in kinematics has been described within healthy populations. Therefore, this study aims to identify and describe healthy phenotypes with homogenous knee kinematics using a clustering approach. A total of 120 healthy knees from 64 participants underwent dynamic CT scanning during knee extension and flexion. Eight tibiofemoral (TF) and patellofemoral kinematic parameters were extracted, after which K-means clustering was applied to identify homogenous kinematic clusters. Kinematic phenotypes were obtained by calculating the median and interquartile range (IQR) for all kinematic parameters per cluster. Two distinct clusters were found, comprising 53 (Cluster 1) and 67 (Cluster 2) knees. Statistically significant differences between the clusters were found in six out of eight kinematic parameters. The most notable differences were observed in TF rotations, with cluster 1 exhibiting a greater amount of internal and adduction rotation of the tibia compared to cluster 2. The two kinematic phenotypes provide new insights into the nuanced variation within a healthy cohort and can serve as reference for future studies evaluating pathological kinematic phenotypes using dynamic CT.

Performance of Artificial Neural Network Compared to Multi-Linear Regression in Prediction of Countermovement Jump Height

Previous research has used primarily linear regression models to predict jump height and establish contributors of performance. The purpose of this study was to compare the performance of artificial neural network (ANN) and multi-linear regression (MLR) in prediction of countermovement jump (CMJ) height and investigating the contribution of kinematic variables to CMJ performance. Thirty-four healthy young male athletes performed a total of 204 CMJ while eight kinematic variables (the hip, knee, and ankle angles at the begging of the concentric phase of CMJ, the hip and knee take-off angles, and the shoulder, hip, and knee maximum angular velocities) were used as inputs to ANN and MLR to predict CMJ height. The correlation coefficients between the jump height and the predicted value by the developed models indicated that ANN predict CMJ height better than MLR (R2 = 0.68 compared to R2 = 0.44). Moreover, the root mean squared error of prediction showed better performance of the ANN rather than the MLR (4.8 cm compared to 5.3 cm). The shoulder and hip maximum angular velocities were the most important contributors, and then the hip and knee take-off angles contributed to CMJ height. In conclusion, implementing ANN to identify key variables of performance may also be relevant for other sport skills.

Breaststroke and butterfly intercycle kinematic variation according to different competitive levels with Statistical Parametric Mapping analysis

Breaststroke and butterfly are complex swimming techniques requiring refined motor skills to perform successfully, with coordinated and consistent interaction between propulsive and resistive forces being decisive when considering swimmers expertise. The current study analysed those techniques intercycle kinematic variation in two swimmers cohorts. Twenty elite and 15 national level swimmers performed one 25 m breaststroke and one 25 m butterfly sprints, with an underwater camera recording images at 120 Hz in the sagittal plane. Mean velocity, maximum and minimum velocities, stroke rate and length, intracycle velocity variation and phases relative duration were calculated for consecutive cycles (elite: five breaststroke/butterfly, national level: eight breaststroke/seven butterfly). The two highest peaks and the lower peak in between in breaststroke were also addressed. Intercycle and inter-groups analysis were performed using ANOVA, ANCOVA and Statistical Parametric Mapping. Elite and national level differed regarding breaststroke mean and maximum velocities, 1st and 2nd peaks and minimum between peaks (1.30 ± 0.02 vs 1.15 ± 0.02 m/s, 2.13 ± 0.05 vs 1.88 ± 0.06 m/s, 1.63 ± 0.05 vs 1.48 ± 0.05 m/s, 2.13 ± 0.05 vs 1.86 ± 0.05 m/s, 1.33 ± 0.04 vs 1.23 ± 0.04 m/s), and butterfly mean, maximum and minimum velocities, stroke rate and intracycle velocity variation, respectively (1.65 ± 0.01 vs 1.50 ± 0.01 m/s, 2.20 ± 0.04 vs 2.09 ± 0.04 m/s, 1.12 ± 0.04 vs 0.79 ± 0.04 m/s, (57.9 ± 0.9 vs 54.9 ± 1.0cycles/min, 18.4 ± 1.3 vs 23.7 ± 1.3 %). Elite and national level swimmers showed consistent breaststroke intercycle kinematic variation, but a butterfly mean velocity decay, with the upper limbs release and recovery, and the outsweep phases originating variability between butterfly cycles. Skill levels contrasted in technical and strategic features at sprint breaststroke and butterfly but showed similar velocity variability between consecutive swimming cycles.

Terra incognita of the uncontrolled manifold (UCM).

The review addresses the central concept of the uncontrolled manifold (UCM) hypothesis, which has become a major framework for analysis of performance-stabilizing motor synergies. The major goals are to summarize the status quo in the field and to ask new questions stimulating new studies. We focus on a few main questions: What is the UCM? What are the likely neural origins of the UCM? How is the UCM reflected in movement patterns? Are properties of the UCM similar in all directions? We contrast experience-based features of movements seen very soon after the movement initiation vs. those based on on-line sensory feedback signals. Further, we address a number of poorly explored issues such as the differences in characteristic times of processes within the UCM and orthogonal to the UCM space, the interplay between movement stability and optimality, the origin of preferred sharing patterns of performance variables across abundant sets of elements and of their inter-trial variability, problems with the UCM-based analysis in different spaces, and likely neurophysiological mechanisms contributing to the UCM formation. In particular, we focus on the UCM in spaces of hypothetical neural control variables, which we associate with the reciprocal and coactivation commands to the effectors. Analysis of performance-stabilizing synergies within the UCM framework in abundant spaces of kinetic, kinematic and electromyographic variables at the selected level of analysis may be practically useful. However, mapping findings in such studies onto neural control mechanisms has been challenging.

The Kinetic and Kinematic Efficacy of Posterior Leaf Spring Ankle-foot Orthosis in Patients with Drop foot

Background: Dorsi flexor weakness is one of the common consequences of stroke with a negative impact on normal walking. Posterior leaf spring (PLS) Ankle Foot Orthosis (AFO) is the most frequent prescription to assist foot clearance and leg propulsion in these patients. However, the real efficacy of this AFO needs more attention. This study aimed to investigate the efficacy of PLS AFO on gait outcomes as the most common AFO in drop foot post-stroke patients. Methods: The study design was a pre–post-test experiments in which twenty drop foot patients with a mean age of 65 years with a mean age of 58.45 (±5.23) years who were 4/5 years post-stroke. They walked at self-selected walking speed on a 10 meters walk away in two conditions of with their own shoes and PLS AFO. The 3D motion capture gait analysis system including 6 vicon cameras and a Kistler force plate were used in order to measure gait kinetic and kinematic variables. For each trial, each joints (ankle, knee and hip) angle, moment and power were averaged over one-minute walking. Results: Walking with PLS showed a statistically significant improve kinetic and kinematic variables in hip, knee and ankle joints included power, moments and angles at entire gait cycle. P&lt;0.05. Conclusions: In our study of stroke patients who were fitted with a PLS AFO, immediate significant improvements occurred in most kinetic and kinematic than shoes only in sacrifice some others.

Potential Effects of Soccer Ball Characteristics on Ball-to-Head Contact: A Systematic Review

Background: The aim of this study was to systematically review research on the effect of soccer ball characteristics on ball-to-head contact. Methods: This systematic review was conducted using electronic databases, which included PubMed, Cochrane, and Web of Science. The search strategy combined keywords related to soccer, the ball and its characteristics, heading, and kinematics variables. Studies analyzing the impact of soccer ball characteristics on heading biomechanics were included. The review included studies using mathematical models, simulations, and human subjects. Results: A total of nine studies were included, highlighting the lack of evidence on this topic. The following ball characteristics were investigated: inflation pressure (n = 7), mass (n = 4), structure/material properties (n = 3), size/diameter (n = 3), and stiffness (n = 3). Most studies used non-human subjects, such as mathematical, simulated, or head-form models. Key findings were as follows: (a) reducing inflation pressure may decrease impact magnitude; (b) ball size may not directly relate to impact magnitude, but one study found that a smaller size resulted in a shorter impact time; (c) lower impact observed with decreasing ball mass; (d) lowering stiffness showed a tendency to lower impact; (e) two studies on water absorption found that wet balls were heavier and had greater impact forces than dry balls; and (f) ball structure and cover material directly influenced impulsive forces. Conclusions: Modifying soccer ball characteristics may reduce heading forces, but the available research has limitations. More controlled studies are needed to determine optimal ball properties for mitigating injury risk during soccer heading. Standardized testing methods can further clarify the biomechanics of heading, supporting ongoing innovations to enhance player experience.

Determination of the mechanical properties of the sacroiliac joint of a dog by imaging measurement methods and model update in a multi‐body model

AbstractThe sacroiliac joint (SIJ) is the articulated connection between the sacrum and the ilium and is a tight, combined, and only slightly mobile joint. In many dogs, the joint becomes stiff with age. As a result, the animal experiences pain while moving. Too little information is known about the degree of stiffening and the physiological range of motion for therapy. Consequently, recording the range of motion of different individuals (healthy and diseased) is a step toward a better understanding of the SIJ syndrome. For the basic investigation of the mechanical properties of the SIJ, post‐mortem examinations are performed on different individuals. To determine the mobility of the joint, the sacrum is fixed and a movement is forced on the ilium using actuators and recording the required forces. In addition, the spatial movement of the ilium and sacrum is measured. The kinematic and dynamic variables can be used to determine the translational and rotational stiffness of the SIJ. As it is not possible to apply directed loads to the ilium, the measurement data is used to determine the elastic parameters of the joint ligaments using heuristic methods. The multi‐body model includes the ilium, the ligaments, and the actuators of the test rig with their spatial orientation.

Influence of video instruction on soccer kick velocity in young players

Soccer is a sport that necessitates proficiency in motor control and cognitive abilities, with kicking serving as a fundamental action. Improving kicking performance is vital for player advancement, leading to the inquiry: “How can video instruction promptly optimize kicking technique in young players?”. This research aimed to investigate the immediate effects of an instructional video on the kinematic variables of kicking to induce an acute alteration in the movement pattern. A cohort of 26 male youths, aged between 10 and 15 years, partook in the study and were segregated into an instruction group (IG) and a control group (CG). The IG received exposure to a video containing specific kicking instructions, while the CG viewed a video lacking such guidance. Both groups were recorded performing penalty kicks before and after viewing the video. Kinematic analysis was carried out utilizing the OpenPose artificial intelligence neural network for pose detection and subsequent 3D reconstruction. The primary discovery was that the length of the last stride (LS) notably increased in the IG following the instructional video. This outcome indicates that video instructions hold promise in promptly enhancing particular aspects of kicking technique in young soccer players.

MTN is all you need: Production of multiple semi-invisible resonances at hadron colliders

The stransverse mass variable [Formula: see text] was originally proposed for the study of hadron collider events in which [Formula: see text] parent particles are produced and then decay semi-invisibly. Here we consider the generalization to the case of [Formula: see text] semi-invisibly decaying parent particles. We introduce the corresponding class of kinematic variables [Formula: see text] and illustrate their mathematical properties. Many of the celebrated features of the [Formula: see text] kinematic endpoint are retained in this more general case, including the ability to measure the mass of the invisible daughter particle from the stransverse mass kink. We describe and validate a numerical procedure for computing [Formula: see text] in practice. We also identify the configurations of visible momenta which result in nontrivial ([Formula: see text]) values, and derive a pure phase-space estimate for the fraction of such events for any N.

Kinematic characterization of backhand stroke accuracy in squash based on kinematic variables between two different skill levels-a preliminary cross-sectional study.

The aim of this study was to compare differences in shot placement and accuracy between national and international level squash players. Squash is a technically demanding sport and understanding the biomechanical characteristics of athletes at different levels is important for developing effective training strategies. The study used a three-dimensional motion analysis system, a high-speed video camera, and a professional tee for biomechanical testing. Participants included national and international level squash players. The kinematic characteristics of the shoulder, elbow, and wrist joints of the upper extremity for backhand strokes, as well as the accuracy of the strokes, were analyzed to compare the differences between the two groups of athletes in terms of stroke posture and accuracy. The kinematic analysis of the backward backhand stroke revealed that national squash players showed significant differences compared to international players in several key parameters. Specifically, national players had significantly greater trunk flexion (P=0.018) and less shoulder medial rotation (P=0.027). They also had lower racket velocity in the X-direction (P=0.043). However, there were no significant differences in trunk lateral flexion (P=0.487), trunk rotation (P=0.293), shoulder extension/flexion (P=0.396), elbow flexion/extension (P=0.818), wrist flexion/extension (P=0.177), wrist rotation (P=0.476), racket pitch (P=0.112), racket velocity in the Y-direction (P=0.587), or racket velocity in the Z-direction (P=0.327). Additionally, data for racket yaw, racket roll, and racket Vx were not provided with significant values, indicating that these parameters do not show significant differences. International level players outperformed national level players in squash stroke accuracy and control. Key kinematic factors influencing accuracy include trunk forward flexion, shoulder abduction, shoulder internal rotation, and racket angles. The study recommends that coaches design training to enhance technical details and positional control to improve squash performance.

Speaking to a metronome reduces kinematic variability in typical speakers and people who stutter.

Several studies indicate that people who stutter show greater variability in speech movements than people who do not stutter, even when the speech produced is perceptibly fluent. Speaking to the beat of a metronome reliably increases fluency in people who stutter, regardless of the severity of stuttering. Here, we aimed to test whether metronome-timed speech reduces articulatory variability. We analysed vocal tract MRI data from 24 people who stutter and 16 controls. Participants repeated sentences with and without a metronome. Midsagittal images of the vocal tract from lips to larynx were reconstructed at 33.3 frames per second. Any utterances containing dysfluencies or non-speech movements (e.g. swallowing) were excluded. For each participant, we measured the variability of movements (coefficient of variation) from the alveolar, palatal and velar regions of the vocal tract. People who stutter had more variability than control speakers when speaking without a metronome, which was then reduced to the same level as controls when speaking with the metronome. The velar region contained more variability than the alveolar and palatal regions, which were similar. These results demonstrate that kinematic variability during perceptibly fluent speech is increased in people who stutter compared with controls when repeating naturalistic sentences without any alteration or disruption to the speech. This extends our previous findings of greater variability in the movements of people who stutter when producing perceptibly fluent nonwords compared with controls. These results also show, that in addition to increasing fluency in people who stutter, metronome-timed speech also reduces articulatory variability to the same level as that seen in control speakers.

Asymmetries in invisible dark matter mediator production associated with tt¯ final states

In this paper, we propose two sets of different CP-sensitive observables inspired by the Higgs production in association with the top quark. We employ a dark matter simplified model that couples a scalar mediator with top quarks. The reconstruction of the kinematic variables is presented at next to leading order (NLO) accuracy for events associated with this massive scalar particle, which is assumed to be vanishing to invisible decays in a detector such as ATLAS. We build these observables by taking advantage of the similarity between the scalar coupling with the top quark and the factorization theorem in the total scattering amplitude, in order to represent the basis in which the phase space is parametrized. A twofold approach employs the direct implementation of the four-momentum phase space measure in building CP sensitive observables such as b2 for the Higgs, and the spin polarization of the top-quark decays in the narrow width approximation for the employed model. We studied the asymmetries of these distributions to test for any improvement in increasing the exclusion region for the gu33S−gu33P parameters associated with this vanishing scalar particle. We have found no significant effect in the exclusion limits by using the forward-backward asymmetry distributions and the full-shaped ones. Considering the case of an invisible mediator with mass of 10−2 GeV for a luminosity of 300 fb−1 expected at the end of Run 3, the best limits for gu33S and gu33P at NLO accuracy were obtained using the variables b˜2y^ and b2 respectively, with corresponding limits set to [−0.0425,0.0425] and [−0.83,0.83] at 68% CL. Published by the American Physical Society 2024

Galerkin’s Method and Multivariate Newton’s Method for the Nonlinear Deformation of the Magneto-Electro-Elastic Bi-Layered Laminates

In this paper, mathematical modelling for the large deformation of a magneto-electro-elastic rectangular bi-layered laminate with general boundary conditions is presented. Constitutive equations involving the magneto-electro-elastic (MEE) material properties are introduced, Maxwell equations accounts for the electric and magnetic effects are also utilized. First-order shear deformation theory (FSDT) considering the von Karman nonlinear strain is adopted, and the plain strain/stress assumption applicable for thin plate analysis is used. A rather compact set of governing equations related to kinematical variables, electric/magnetic potentials and the Airy stress function is obtained as a consequence of the preliminary condensation for the electro-magnetic state to the plate kinematics. Semi-analytic solution for a bi-layered BaTiO3-CoFe2O4 laminate with specified boundary conditions subjected to various external applied loads is performed. By employing the Bubnov-Galerkin method, the set of nonlinear partial differential equations is transformed to a set of third-order nonlinear algebraic equations for the static deformation due to applied load. Numerical results are carried out by using the multivariate Newton's method with respect to various volume fractions indicating the volume ratio between piezoelectric BaTiO3 layer and piezomagnetic CoFe2O4. From the result, the nonlinearity of the von Karman strain appears to enhance system rigidity as smaller deformations will be detected when external load is applied. Also, some other interesting results are obtained which could be useful to future analysis and design of multiphase composite plates.