Kinematic Variables Research Articles

Force-Velocity Profile in Middle- and Long-Distance Athletes: Sex Effect and Impact on Endurance Performance Determinants

Background: Muscle strength plays a critical role in the performance of middle- and long-distance athletes. However, the vertical force–velocity (F–V) profile has not been studied in this population. The objectives of this study were twofold: (i) to characterize the F–V profile in middle- and long-distance athletes and (ii) to explore its relationship with physiological and biomechanical performance variables. Methods: Thirty-nine highly trained athletes (13 middle-distance and 26 long-distance athletes), comprising men (18) and women (21), participated in this study. Each athlete performed a squat-jump to determine their F–V profile, followed by two 5 min bouts of low-intensity running and a graded exercise test to assess physiological and kinematic parameters. Results: Significant differences (p ≤ 0.05) were observed in maximal estimated power (Pmax) and jump height between middle- and long-distance female athletes (21.20 ± 4.78 W·kg−1 vs. 15.80 ± 2.83 W·kg−1; 26.00 ± 0.05 cm vs. 19.50 ± 0.03 cm), and between male and female long-distance athletes (19.70 ± 2.87 W·kg−1; 24.10 ± 0.02 cm). Stride length during low intensity running showed significant correlations with Pmax (r = 0.340) and jump height (r = 0.374). Pmax was positively associated with running economy (RE) (r = 0.396) and VO2max (r = 0.346), and negatively correlated with F–V imbalance (FVimb) (r = −0.531). Conclusions: Middle- and long-distance athletes demonstrate similar F–V profiles; however, middle-distance athletes exhibit a rightward shift, resulting in higher Pmax and jump height, particularly among women. Nevertheless, F–V profile characteristics display only weak associations with physiological and kinematic variables which directly influence performance.

Exploring the Feasibility of Head-Tracking Data for Cybersickness Prediction in Virtual Reality

Cybersickness remains a significant barrier to the widespread adoption of virtual reality (VR) technology. Traditional methods for predicting cybersickness rely on self-reported questionnaires or physiological signals from specialized sensors, which have their limitations. This study explores the potential of using real-time, easily acquired head-tracking data (HTD) from standard VR headsets as a scalable alternative for estimating cybersickness. Twelve participants engaged in a VR session using an Oculus Quest 2 headset while their HTD were recorded. Kinematic metrics such as linear and angular velocity, acceleration, and jerk were computed from the HTD, including positional and angular parameters. Participants’ cybersickness levels were assessed using the Virtual Reality Sickness Questionnaire. While exploratory data analysis revealed no significant direct correlation between individual kinematic variables and cybersickness scores, machine learning models were employed to identify predictive patterns. Subsequently, four regression models, including Random Forest, Gradient Boosting, K-Nearest Neighbors, and Support Vector Machines, were trained and evaluated using the computed kinematic features to predict the cybersickness score. Among these, the Gradient Boosting model demonstrated superior performance, accurately predicting cybersickness scores with normalized differences less than 3.08% on unseen data. This approach offers a scalable and practical solution for real-time cybersickness prediction in VR applications and compliments other techniques that rely on physiological sensors, hardware, or user profiles.

Factors Relating to Sprint Swimming Performance: A Systematic Review.

Swimming performance depends on a wide variety of factors; however, the interaction between these factors and their importance varies between events. In sprint events, the characterized pacing underlines its specific development, as swimmers must achieve the highest possible speed while sustaining it to the greatest extent possible. The aim of this review was to identify the key factors underlying sprint swimming performance and to provide in-depth and practical evidence-based information to optimize performance. The review protocol was not registered. PubMed, Web of Science and Scopus databases were searched up to October 31, 2023. Studies involving competitive swimmers and investigating sprint swimming performance were included, while studies conducted with young or masters' swimmers, triathletes or waterpolo players or not investigating sprint swimming performance were excluded. The Downs and Black Quality Assessment Checklist was performed on the included articles to assess the methodological quality. After applying the PICOS framework, 39 of the 1330 articles initially identified were included according to the PRISMA guidelines. The included records focused mainly on dry-land strength and in-water forces of both upper and lower limbs. A wide range of kinematic variables were also examined, together with the importance of anthropometric and various physiological parameters. This review highlights the importance of developing muscular strength and effectively transferring it to performance in the water. The evidence suggests that muscular development should prioritize enhancing velocity and effective displacement, rather than merely increasing force and performance in loaded tests. However, further research is needed to confirm this. While in-water forces have been well studied, there is a notable lack of analysis regarding drag. The optimal balance between stroke rate and stroke length should be determined individually, with a primary focus on achieving a high stroke length from a high stroke rate. Although anthropometry may play an important role in performance, the interaction of these traits appears to be complex, suggesting that other factors may be more important in determining performance outcomes. From a physiological perspective, the results indicate that the lactate peak and rate of accumulation should be thoroughly developed. Notwithstanding, this review shows the lack of a solid body of knowledge on the importance of anaerobic and especially aerobic factors. Finally, the absence of a list of potential confounders, together with the lack of high-quality studies involving elite swimmers (level 1 and 2), complicates the interpretation of the results.

Interdependence patterns of multi-frequency oscillations predict visuomotor behavior

Abstract We show that sensorimotor behavior can be reliably predicted from single-trial EEG oscillations fluctuating in a coordinated manner across brain regions, frequency bands and movement time epochs. We define high-dimensional oscillatory portraits to capture the interdependence between basic oscillatory elements, quantifying oscillations occurring in single-trials at specific frequencies, locations and time epochs. We find that the general structure of the element-interdependence networks (effective connectivity) remains stable across task conditions, reflecting an intrinsic coordination architecture and responds to changes in task constraints by subtle but consistently distinct topological reorganizations. Trial categories are reliably and significantly better separated using oscillatory portraits, than from the information contained in individual oscillatory elements, suggesting an inter-element coordination-based encoding. Furthermore, single-trial oscillatory portrait fluctuations are predictive of fine trial-to-trial variations in movement kinematics. Remarkably, movement accuracy appears to be reflected in the capacity of the oscillatory coordination architecture to flexibly update as an effect of movement-error integration.

Analytical solutions for the stability analysis of coupled shear walls: Three-field CTB beam

To date, no closed-form analytical solutions have been proposed for calculating the global critical buckling load of symmetric and asymmetric coupled shear walls using a novel Three-field CTB continuous model. In this model, the coupled shear wall is represented as a three-field continuous system, formed by the parallel coupling of a Timoshenko beam with axial extensibility (representing the two shear walls) and a pure shear beam (representing the coupling beams), connected by rigid links. This continuous model, developed using a displacement-based approach and energy equivalence, effectively captures the three typical behaviors of a coupled shear wall: global bending, global shear, and local bending. Additionally, it accounts for a recently identified behavior arising from the local shear deformation of the walls, which has been largely overlooked in existing literature. Due to the complexity of its equilibrium equations, characterized by strong couplings among the three kinematic variables, solutions have been limited to static and dynamic analyses, restricting its application to stability analysis. To address this limitation, this study proposes, for the first time, three analytical solutions for the stability analysis of coupled shear walls subjected to arbitrary vertical loads. The first solution is an approximate yet accurate method that decouples the original model into two independent subsystems. The second provides an exact solution to the differential equation, while the third introduces an additional reduction factor to the exact solution. These proposed solutions offer varying levels of accuracy, all within acceptable engineering tolerances, enabling engineers and researchers to choose the appropriate method based on the required precision.

Effect of Post-Activation Potentiation on Weightlifting Performance and Endocrinological Responses

Purpose: This study examined the acute performance-enhancing effects and endocrinological responses of a supramaximal clean pull performed at 120% of clean and jerk, one repetition maximum, on clean performance. Methods: Eight (n = 8) ranked collegiate level weightlifters attended two days of testing in a randomised order. A control session was used to identify a baseline measure of kinetic and kinematic clean performance and endocrinological status following three cleans interspersed with one-minute recovery between repetitions. The experimental condition required participants to perform a single clean pull at 120% of clean and jerk, one repetition maximum, followed by three minutes recovery, prior to executing three cleans with one-minute recovery between repetitions. All cleans were performed on a dual force plate set up, synchronised with a 3D motion capture system to simultaneously record barbell and ground reaction force data. All endocrinological data were measured prior to the participant warming up and also following each testing protocol. Results: The results indicated that no significant differences were found between the control and PAP condition (p = 0.140–0.902); however, effect sizes from group analysis identified moderately negative to trivial effects across kinetic, kinematic and endocrinological variables (d = −0.30–0.14). Further analysis on an individual level demonstrated values, both negative and positive, ranging from extremely large (d = −4.10) to trivial (d = 0.04). Conclusions: The findings suggest a potentially negative affect of PAP on kinetic and kinematic measures of clean performance. However, individual responses varied, and thus some weightlifters may find this useful.

Kinematic and muscle co-activation patterns in the dominant arm across forehand stroke phases in wheelchair tennis.

This study investigated upper limb kinematics and muscle co-activation in wheelchair tennis players during the forehand stroke. By analyzing linear and angular kinematic variables alongside muscle co-activation patterns, the study aimed to provide insights into the biomechanical mechanisms supporting forehand stroke performance. Fifteen professional male wheelchair tennis players (height: 163.9 ± 2.05cm; mass: 64.1 ± 3.07kg; age: 32.2 ± 7.97years) participated in this study. Electromyographic data from six muscles around the dominant arm joints were recorded using the Myon system. Four fixed GoPro Hero 8 cameras (120Hz) captured 3D video, and kinematic analyses were performed using the APAS system. The forehand stroke was analyzed across three phases: (1) backswing, (2) forwardswing, and (3) follow-through. The results showed significant phase-specific changes in muscle co-activation for the shoulder (p < 0.001), elbow (p < 0.005), and wrist (p < 0.01). Muscle co-activation was highest during the backswing phase, decreased during the forwardswing, and increased again during the follow-through phase. This pattern reflects the need for joint stability and control, particularly when changing stroke direction and slowing the arm after impact. These findings provide novel insights into the kinematic and neuromuscular mechanisms underlying the forehand stroke in wheelchair tennis. The data provide hypotheses about potential training and rehabilitation strategies that should be tested by prospective studies. The results also highlight the unique demands of wheelchair tennis, contributing to inclusive, evidence-based approaches to enhancing performance and safety in disability sports.

Relationship of Age and Running Biomechanics in Female Recreational Runners.

Middle-age and older runners demonstrate differences in running biomechanics compared with younger runners. Female runners demonstrate differences in running biomechanics compared with males, and females experience hormonal changes during menopause that may also affect age-related changes in running biomechanics. The purpose of this study was to determine the relationship between age and running biomechanics in healthy female recreational runners. Fifty-two participants (ages 27-65y) ran on an instrumented treadmill at 2 different self-selected speeds: easy pace and 5km race pace. Lower-extremity kinematic and kinetic variables were calculated from 14 consecutive strides. Linear regression was used to determine the relationship between age and lower-extremity running biomechanics, controlling for self-selected running speed. There was a negative relationship between age and easy pace (R = -.49, P < .001) and age and 5km race pace (R = -.43, P = .001). After controlling for self-selected running speed, there were no significant relationships between age and running biomechanics for either running speed. Several biomechanical variables were moderately to strongly correlated with running speed. Running speed should be considered when investigating age-related differences in running biomechanics.

Exploring Sex-Based Variations in Head Kinematics During Soccer Heading.

While studies indicate that females experience a higher concussion risk and more severe outcomes in soccer heading compared to males, comprehensive data on the underlying factors contributing to these sex-based differences are lacking. This study investigates the sex differences in the head-to-ball impact kinematics among college-aged soccer headers in a laboratory-controlled setting. Forty subjects (20 females, 20 males) performed ten headers, and impact kinematics, including peak angular acceleration and velocity (PAA, PAV) and peak linear acceleration (PLA), were measured using mouthguards. Video recordings verified impacts and impact locations. Participants' head mass was estimated from their weights. The relationship between head mass and kinematic parameters was analyzed using Pearson correlation. The effects of head mass, sex, and impact location on kinematic parameters were assessed using MANOVA with and without head mass as a covariate. Results showed that head mass, larger in males than females, significantly affects PAA and PLA, the greater the head mass, the lower PAA and PLA. However, head mass has no effect on PAV. Females showed significantly higher PAA and PLA components but no significant differences in PAV. Impact location significantly influenced PAV, showing higher magnitudes for frontal impacts compared to top-front impacts, with no significant effects on PAA and PLA. Our results agree with epidemiological evidence that female soccer players face greater concussion risks than males, which can be attributed to their higher header-induced PAA. Future research could consider interventions like changing ball pressure, using protective headgear, and improving heading techniques to reduce high-magnitude accelerations in females.

Analysing head and trunk motion in the judo osoto-gari technique: relationship to sweeping-leg velocity.

Osoto-gari is a leg throw technique that primarily relies on the hip extension to initiate the sweeping motion of the leg. A high sweep contact velocity is a crucial factor in efficiently executing this technique. While some literature emphasises whole-body coordination in the leg-sweeping action, the roles of trunk and head motion remain unclear. This study investigates head and trunk movements (including the pelvic and upper torso) contributing to higher leg-sweep velocities when executing the judo osoto-gari. Kinematic data were collected from 17 male black-belt judokas using a motion capture system (250 Hz). Pearson product-moment correlation and stepwise linear regression were used to identify kinematic variables linked to the sweeping-leg velocity at sweep contact (SC). Six out of twenty-four variables correlated with sweeping-leg velocity at SC. A stepwise regression model (adjusted R2 = 0.53, p = 0.009) predicted sweeping-leg velocity based on head-tilt angle at maximum sweeping-leg height (MSH) and SC, head-tilt angular velocity at MSH, and trunk-tilt angular velocity at MSH. The findings of this study indicate that (1) increasing the forward angle of the head aids the visual system in rapidly processing spatial information about the target position, thus facilitating the execution of the leg sweep, and (2) a greater forward-tilt rotation of the head, which leads to rapid trunk rotation, is conducive to enhancing sweeping-leg velocity.

Difference in movement coordination and variability during Five-Repetition Sit-to-Stand between people with and without Chronic Low back pain.

Chronic low back pain (CLBP) affects people's activities of daily living, including sitting down and standing up. Movement pattern analyses during five-repetition sit-to-stand (5RSTS) may allow CLBP status differentiation. 44 CLBP and 22 asymptomatic participants performed 5RSTS in this study, with their trunk and lower limb movements recorded using 3-dimensional motion capture system. Joint active range of motion, joint maximal velocity, joint and segment continuous relative phase (CRP) were analyzed. Mean absolute relative phase (MARP) and deviation phase (DP) variables were calculated in CRP analysis. Between-group kinematic variables were compared using One-way Multivariate Analysis of Covariance (MANCOVA). Significant variables from different methods were compared using binomial logistic regression to assess accuracy for CLBP status. Results showed that segmental CRP is the most sensitive method for CLBP assessment, with the CLBP group femur-to-pelvis and lumbar-to-pelvis movement coordination was more in-phase MARP (F(8,56)=7.127, p<0.001, Wilks'Λ=0.441, ηp2=0.559) and stable DP (F(8,56)=4.585, p<0.001, Wilks'Λ=0.551, ηp2=0.449) during both standing up and sitting down. Utilizing CRP variables yielded Nagelkerke R2=0.708 and overall correct classification of 93% for CLBP status. Individuals with CLBP exhibited distinct movement coordination and stability, which should be considered in CLBP assessments and intervention. Variable combination from the segment analysis was found to be the most predictive to CLBP status, and significantly different to the results obtained from joint analysis, highlighting the necessity for CRP method standardization in future studies.

In vivo kinematics during step ascent: Changes to the knee associated with osteoarthritis

BackgroundStair climbing is a kinematically demanding activity, essential for maintaining independence and quality of life, yet is often impaired in patients with knee osteoarthritis (OA). The purpose of this study was to examine differences in kinematics of a step-up movement between participants with osteoarthritis and asymptomatic controls. MethodsThirty participants with end-stage OA awaiting total knee arthroplasty (TKA) and twenty-eight sex and age-similar asymptomatic participants were recruited. Participants performed a step-up task which was imaged via single-plane fluoroscopy. 3-dimensional prosthesis computer-aided design models were registered to the fluoroscopy, yielding in-vivo kinematic data. Kinematic variables of position, displacement, and rate-of-change in six degrees of freedom were compared between the two groups. ResultsOA knees exhibited significantly different kinematics to asymptomatic knees during step-up. Knees with OA demonstrated a reduced terminal extension angle, inferior translation and increased internal rotation throughout the movement compared to asymptomatic. OA participants exhibited more variability in kinematic parameters compared to asymptomatic controls, reflecting the heterogeneity within OA pathology. ConclusionThe findings of this study indicate that knee kinematics, particularly rotation, differ significantly between OA and asymptomatic knees during step-up. Optimising rotational profiles in OA knee management could help optimise patient function and inform rehabilitation and surgical protocols.

Classification of static plane symmetric spacetime according to their self similar vector fields

Abstract This article discusses the use of self-similar symmetry to analyze static plane symmetric spacetime. A computer algorithm is employed to convert the symmetry equations, resulting in a tree structure known as a Riff tree, which is utilized for analyzing the aforementioned symmetry within the specified spacetime. The tree comprises several pivots and branches, with the pivots being subject to specific differential conditions on the metric functions. Furthermore, explicit formulas for the metrics and their corresponding self-similar vector fields (SSVFs) are derived by solving the set of equations using these constraints. Additionally, this work investigates the bounds for certain energy conditions as well as the kinematic variables.

Analytical study of some kinematics variables for the last steps in the javelin event and their relationship with performance

Kinematics is one of the branches of biomechanics used in the field of sports, and it is one of the important tools that aid in the diagnosis of faults and virtues of the technical performance of the movement. javelin. This effectively goes through multiple stages the require continuous biomechanical evaluation in order to accomplish advance achievement. This study's primary objective was to determine the values of some kinematic variables of the last three steps of the javelin throw by senior throwers from Erbil provence clubs. The the research population consists of senior throwers in Erbil governarate clubs who participated in the Erbil competition numbered (12) individuals, furthermore, the sample of (5) players intentionally selected from population. The results show that there is a correlation between the length of the second-to-last and last step in addition to correlation between vertical velocity in the third step with javalin achievement. The researchers concluded that the optimal extrusion angle (45 degrees) is not optimal for all events; although the javelin is a projectile, a 45-degree angle is not commonly used in the javelin (angle younger had a correlation with the best achievement of the angle 45).

High resolution kinematic approach for quantifying impaired mobility of dystrophic zebrafish larvae.

Dystrophin-deficient zebrafish larvae are a small, genetically tractable vertebrate model of Duchenne muscular dystrophy well suited for early stage therapeutic development. However, current approaches for evaluating their impaired mobility, a physiologically relevant therapeutic target, are characterized by low resolution and high variability. To address this, we used high speed videography and deep learning-based markerless motion capture to develop linked-segment models of larval escape response (ER) swimming. Kinematic models provided repeatable, high precision estimates of larval ER performance. Effect sizes for ER peak instantaneous acceleration and speed, final displacement, and ER distance were 2 to 3.5 standard deviations less for dystrophin-deficient mutants vs. wild-types. Further analysis revealed that mutants swam slower because of a reduction in their tail stroke frequency with little change in tail stroke amplitude. Kinematic variables were highly predictive of the dystrophic phenotype with ≤ 3% of larvae misclassified by random forest and support vector machine models. Tail kinematics also performed as well as in vitro assessments of tail muscle contractility in classifying larvae as mutants or wild-type, suggesting that ER kinematics could serve as a non-lethal proxy for direct measurements of muscle function. In summary, ER kinematics can be used as precise, physiologically relevant, non-lethal biomarkers of the dystrophic phenotype. The open-source approach described here may have applications not only for studies of skeletal muscle disease but for other disciplines that use larval mobility as an experimental outcome.

Evolution of non-static fluid for irreversible gravitational radiation in Palatini [formula omitted] gravity

In this manuscript, we focus on a comprehensive investigation of non-static axially symmetric fluid distributions in the background of Palatini F(R) gravity. To do so, a general framework is established to examine the irreversible nature of gravitational radiation. To begin with, modified Einstein field equations (EFE), kinematical variables, and transport equations are derived using connection symbols which help understand the thermodynamic characteristics of considered compact systems. Afterwards, we analyze the Tolman criteria for the thermodynamic equilibrium of a non-static axially symmetric fluid distribution and deduce that non-static fluids do not arise from the emission of gravitational radiation in Palatini F(R) gravitational theory. This result highlights that irreversibility is linked to gravitational wave emission and supports Bondi’s conjecture. Subsequently, we explore the notable results that arise from this hypothesis in the Palatini F(R) formalism.

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 ≲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 ~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 ~50 au) is also supported by redshifted CO and 13CO 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 (~80 km s−1) 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 ~0.″02–0.″04 (~ 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 (≲0.5–1 yr) derived from observed velocity gradients in the compact ionized wind. Radiative transfer modeling indicates an average electron temperature of ~15 000 K and reveals a nonuniform density structure within the ionized wind, with electron densities ranging from ne≈106 to 108 cm−3. 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.

Comparison of In-Game Trunk and Upper Extremity Kinematics Between Fastballs, Breaking Balls, and Changeups in NCAA Division I Collegiate Baseball Pitchers.

Previous biomechanical analyses of baseball pitching report similar kinematics between pitch types. However, prior studies were conducted in a controlled laboratory environment. This study aimed to compare in-game trunk and upper extremity kinematics between fastballs, breaking balls, and changeups to determine whether there are kinematic differences that may affect performance as well as to provide new insights into potential risk factors for injury. It was hypothesized that there would be kinematic differences between pitch types. Descriptive laboratory study. A retrospective analysis was conducted of markerless motion capture data collected during National Collegiate Athletic Association Division I baseball games. Included were 34 pitchers who pitched at least 3 pitches of each type (fastball, breaking ball, changeup) during competition. A 1-way repeated-measures multivariate analysis of variance (MANOVA) was used to test differences between pitch types, and Bonferroni post hoc tests were used to test pairwise comparisons. The MANOVA revealed a significant effect of pitch type (P < .001), and follow-up univariate tests found a significant main effect of pitch type for 12 of the 15 kinematic variables analyzed. Post hoc Bonferroni tests revealed that maximum shoulder external rotation was significantly greater during fastballs than breaking balls. At foot contact, significantly less shoulder external rotation was seen during changeups compared with fastballs and breaking balls. At the time of ball release, changeups had significantly less trunk lean and less trunk flexion than fastballs and breaking balls, and fastballs had a significantly smaller arm slot angle than breaking balls and changeups. Collegiate baseball pitchers displayed numerous kinematic differences between pitch types during competitive play, some of which are known influencers of pitching kinetics. This study offers a novel perspective regarding kinematic differences between different pitch types during competition. These results are comparable to the findings of laboratory studies and provide valuable insights into potential injury mechanisms.

Fusing photons into nothing, a new search for invisible ALPs and Dark Matter at Belle II

We consider an axion-like particle coupled to the Standard Model photons and decaying invisibly at Belle II. We propose a new search in the e+e− + invisible channel that we compare against the standard γ + invisible channel. We find that the e+e− + invisible channel has the potential to ameliorate the reach for the whole ALP mass range. This search leverages dedicated kinematic variables which significantly suppress the Standard Model background. We explore the implications of our expected reach for Dark Matter freeze-out through ALP-mediated annihilations.

Sericin-Enriched Rabbit Semen Preservation: Implications for Short-Term Storage Quality and Fertility at 4 or 15 °C.

The influence of sericin supplementation and chilling temperatures (4 and 15 °C) on the short-term storage quality and fertility of rabbit semen was assessed over 72 h of storage. In experiment 1, pooled semen (five replications) was diluted to a concentration of 50 M mL-1, and assigned to control, 0.1%, and 0.5% sericin groups, stored at 4 or 15 °C. Sperm motility, sperm kinematics, viability, and membrane and acrosome integrity were assessed at 0, 24, 48, and 72 h of storage. Experiments 2 and 3 were conducted to observe the effect of sericin on bacterial growth and in vivo fertility. The results of experiment 1 showed that sericin treatment, storage temperature, and storage duration influenced progressive and total sperm motility. The storage duration affected all sperm kinematics variables, whereas VCL, VSL, VAP, and BCF sperm kinematics altered in response to sericin treatment and storage temperature. Similarly, significant effects of sericin treatment, storage temperature, and storage duration were observed for acrosome integrity, sperm membrane integrity, and sperm viability. The results of experiment 2 indicated the antimicrobial effects of sericin when sperm were stored at 15 °C for 72 h. While promising pregnancy outcomes were observed with sericin-treated sperm for 72 h, these results were not significantly different. This study conclusively demonstrates that sericin treatment enhances the quality of rabbit semen when stored at lower temperatures for longer durations. The antimicrobial effects of sericin could be a contributing factor to the improved in vitro and in vivo fertility of rabbit sperm.