Fast Movements Research Articles

The Balance Reaction Ability of Teenagers Based on the Evaluation Model of Unbalanced Sports Quotient.

Dynamic balance is particularly important for the maintenance, transformation, and restabilization of various postures of the human body. Combined with the characteristics of unbalanced sports events, although there is no physical contact in sports events, it has intense antagonism due to the constant change of body movement. Athletes need to have the ability of fast movement and continuous high-intensity multibeat confrontation. They need to adjust their body posture any time according to the situation, constantly move their body from one side to the other side in fast movement, and constantly change between being imbalanced and being stable to keep the center of gravity stable and adjust their body posture. Combining with the characteristics of unbalanced sports, this paper is aimed at the problem that young athletes have poor dynamic balance ability and cannot maintain the stability of their body's center of gravity in the process of fast multidirectional movement and braking. The supporting leg needs ankle dorsiflexion, knee flexion, and hip flexion during SEBT testing. Therefore, the lower limb needs sufficient range of motion, strength, proprioception, and neuromuscular control ability to achieve the optimal test results. A randomized controlled experiment was used to test whether there were significant differences in the test indicators between the experimental group and the control group before and after the experiment by using a paired test. The test indicators between the experimental group and the control group before and after the intervention were tested by independent sample test to explore the influence of core balance training on the dynamic balance ability of teenagers in unbalanced sports. Through analysis, it is proved that strengthening balance exercise can significantly improve the functional movements and physical fitness of adolescents, which is of great significance to the development of basic flexibility and stability of joints and the strengthening of weak chain muscles.

Analisis Kinematik Singularty Pada Manipulator 7 DOF Dengan Software Simulasi ROBOAnalyzer

Studies related to manipulators are still being carried out, along with the times and needs. Utilization in manufacturing and fabrication has led to the development of many manipulators. Smooth, fast, and accurate movement continue to be developed. In the case of the multi manipulator, 7 DOF (Degree of Freedom) is a type of manipulator that has special features in terms of joints. Inverse kinematic is a parameter used to control the orientation and movement of the manipulator. 7 DOF has three singularity wrist, elbow, and shoulder. In the simulation, each singularity produces an inverse kinematic matrix which is used to control the movement of the manipulator. The method used is to determine the angle of motion of the joint (continues joint angel) with simulation to produce calculations that are fast, precise, accurate, and stable. The target of each joint with the theta value that has been determined by the singularity was successfully carried out with an error of 0%.

Direct and remote induced actuation in artificial muscles based on electrospun fiber networks

The present work reports a new configuration of soft artificial muscle based on a web of metal covered nylon 6/6 micrometric fibers attached to a thin polydimethylsiloxane (PDMS) film. The preparation process is simple and implies the attachment of metalized fiber networks to a PDMS sheet substrate while heating and applying compression. The resulting composite is versatile and can be cut in different shapes as a function of the application sought. When an electric current passes through the metallic web, heat is produced, leading to local dilatation and to subsequent controlled deformation. Because of this, the artificial muscle displays a fast and ample movement (maximum displacement of 0.8 cm) when applying a relatively low voltage (2.2 V), a consequence of the contrast between the thermal expanse coefficients of the PDMS substrate and of the web-like electrode. It was shown that the electrical current producing this effect can originate from both direct electric contacts, and untethered configurations i.e. radio frequency induced. Usually, for thermal activated actuators the heating is produced by using metallic films or conductive carbon-based materials, while here a fast heating/cooling process is obtained by using microfiber-based heaters. This new approach for untethered devices is an interesting path to follow, opening a wide range of applications were autonomous actuation and remote transfer of energy are needed.

Dynamic gesture recognition based on YOLOv4 and deep-sort methodological research

The dynamic gesture trajectory recognition results are low accurate and poor real-time due to the problems of occlusion, complex background and fast gesture movement. In this paper, we take advantage of the advantages of machine vision to extract the video keyframes by the three-frame differential method and use the annotation software to produce the dataset. The you only look once 4 (YOLOv4) algorithm is improved to reduce the redundancy of the network structure and enhance the applicability of the feature map for hand gesture recognition. Combined with the Deep-sort real-time tracking feature, the hand motion trajectory is obtained by introducing the epiphenomenal features to effectively avoid the situation that the object is not tracked when it is obscured. To avoid the problem of gradient disappearance during deep network training, the DenseNet-BC-169 network is used to balance the recognition rate and training time for gesture trajectory classification. Compared with FLIXT, the winner of the dynamic gesture recognition challenge, the final results showed a 6.13% improvement in accuracy and video processing with the IsoGD dataset reached 31fps, validating the effectiveness of this method.

Low Gain Values of the Vestibulo-Ocular Reflex Can Optimize Retinal Image Slip.

The angular vestibulo-ocular reflex (aVOR) stabilizes retinal images by counter-rotating the eyes during head rotations. Perfect compensatory movements would thus rotate the eyes exactly opposite to the head, that is, eyes vs. head would exhibit a unity gain. However, in many species, but also in elderly humans or patients with a history of vestibular damage, the aVOR is far from compensatory with gains that are in part considerably lower than unity. The reason for this apparent suboptimality is unknown. Here, we propose that low VOR gain values reflect an optimal adaptation to sensory and motor signal variability. According to this hypothesis, gaze stabilization mechanisms that aim at minimizing the overall retinal image slip must consider the effects of (1) sensory and motor noise and (2) dynamic constraints of peripheral and central nervous processing. We demonstrate that a computational model for optimizing retinal image slip in the presence of such constraints of signal processing in fact predicts gain values smaller than unity. We further show specifically for tadpoles of the clawed toad, Xenopus laevis with particularly low gain values that previously reported VOR gains quantitatively correspond to the observed variability of eye movements and thus constitute an optimal adaptation mechanism. We thus hypothesize that lower VOR gain values in elderly human subjects or recovered patients with a history of vestibular damage may be the sign of an optimization given higher noise levels rather than a direct consequence of the damage, such as an inability of executing fast compensatory eye movements.

Conceptualizing business logistics as an ‘apparatus of security’ and its implications for management and organizational inquiry

Global commodity capitalism necessitates the fast and efficient movement of all manner of entities across the globe. Importantly, this commercial flow needs to be secured against the undocumented and unregulated flow of illegitimate people, finance and information, counterfeits, drugs, terror and other undesirables. The organizational practices of business logistics are central for achieving this objective. Yet they have received little attention in management and organization studies to date. We suggest a fruitful avenue is via Foucault’s notion of ‘biopower’ – particularly his less discussed concept (in management studies, at least) of an apparatus of security. This is useful for understanding the emergent organizational/management practices of security in the border spaces in which business logistics operate. If ‘Society Must Be Defended’, as Foucault ironically notes in his famous lecture series that introduces biopower, then so too must contemporary organizations and their net-like activities within the global economy.

An Effective Algorithm to Analyze the Optokinetic Nystagmus Waveforms from a Low-Cost Eye Tracker.

Objective: Most neurological diseases are usually accompanied by changes in the oculomotor nerve. Analysis of different types of eye movements will help provide important information in ophthalmology, neurology, and psychology. At present, many scholars use optokinetic nystagmus (OKN) to study the physiological phenomenon of eye movement. OKN is an involuntary eye movement induced by a large moving surrounding visual field. It consists of a slow pursuing eye movement, called “slow phase” (SP), and a fast re-fixating saccade eye movement, called “fast phase” (FP). Non-invasive video-oculography has been used increasingly in eye movement research. However, research-grade eye trackers are often expensive and less accessible to most researchers. Using a low-cost eye tracker to quantitatively measure OKN eye movement will facilitate the general application of eye movement research. Methods & Results: We design an analytical algorithm to quantitatively measure OKN eye movements on a low-cost eye tracker. Using simple conditional filtering, accurate FP positions can be obtained quickly. The high-precision FP recognition rate is of great help for the subsequent calculation of eye movement analysis parameters, such as mean slow phase velocity (MSPV), which is beneficial as a reference index for patients with strabismus and other eye diseases. Conclusions: Experimental results indicate that the proposed method achieves faster and better results than other approaches, and can provide an effective algorithm to calculate and analyze the FP position of OKN waveforms.

Antenna movements as a function of odorants’ biological value in honeybees (Apis mellifera L.)

In honeybees, the antennae are highly mobile sensory organs that express scanning movements in various behavioral contexts and toward many stimuli, especially odorants. The rules underlying these movements are still unclear. Using a motion-capture system, we analyzed bees’ antennal responses to a panel of pheromonal and other biologically relevant odorants. We observed clear differences in bees’ antennal responses, with opposite movements to stimuli related to opposite contexts: slow backward movements were expressed in response to alarm pheromones, while fast forward movements were elicited by food related cues as well as brood and queen related pheromones. These responses are reproducible, as a similar pattern of odor-specific responses was observed in bees from different colonies, on different years. We then tested whether odorants’ attractiveness for bees, measured using an original olfactory orientation setup, may predict antenna movements. This simple measure of odorants’ valence did however not correlate with either antennal position or velocity measures, showing that more complex rules than simple hedonics underlie bees’ antennal responses to odorants. Lastly, we show that newly-emerged bees express only limited antennal responses compared to older bees, suggesting that a significant part of the observed responses are acquired during bees’ behavioral development.

VALIDNOST I POUZDANOST TESTA ZA PROCENU VREMENA REAKCIJE I BRZINE KRETANJA U ODBRAMBENOM KOŠARKAŠKOM STAVU

The aim of the present study was to examine the content validity and reliability of the newly developed Reaction Time and Defensive Slide Test (RTADST). Thirty-six female basketball players were recruited from three professional State Basketball league of Bosnia and Herzegovina clubs (age: 18.81 ± 2.58 years) who completed three separate trials of the RTADST with each trial consisting of fast shuffling movements left and right. Each athlete performed the test 3 times in one day, and repeated testing was conducted the following day at evening basketball sessions. The RTADST relative reliability was evaluated by Cronbach’s alpha and ICC. Cronbach’s alpha coefficient was 0.81 which indicates good reliability. When recommendations from Bucheit et al. (2011) were taken into account, the value of ICC <0.69 indicated poor reliability. Absolute reliability of RTADST was assessed by CV, and its value was 5.3%, which is somewhat above the 5%, or the limit of acceptable reliability. Parameters of relative and absolute reliability after the exclusion of the first trial (familiarization with the test task), were more acceptable. Cronbach’s alpha coefficient was 0.90 and ICC = 0.82 compared to the one from all three trials. Considering absolute reliability, it could be concluded that the test is reliable since the CV value is below 5% (3.9%). Reliability between two days was assessed by ICC, and its value was 0.74, which confirms good reliability. Finally, the RTADST can be considered as a valid test that discriminates female basketball perimeter players and post players in reaction time and basketball defensive slide speed, while conditioning programs for the development of these abilities need to be carried out with a tool such is RTADST for the initial and final evaluation of these abilities.

Sitan Kale Fortress - Bansko City

Located in the area Kalyata, only about 5 km. southwest of the resort town of Bansko, "Sitan Kale" (also known as "Kalyata", "Stana", "Satan Kale", "Sitan Kalesi") is a late ancient fortress, which is one of the largest fortresses discovered in this region. The fortress is late antique and according to experts it was built to guard the Razlog valley and more precisely the Roman road that passed through the valley of Mesta through Pirin and reached the valley of the river Struma. The first information about Sitan Calais came to us thanks to the Byzantine chronicler George Kedrin, who described it as a "remarkable city", which archaeologists say speaks of its great importance and the important role it played in protecting the "caravan route". The fortification is located in a strategic place, which allows for fast movement, wide surveillance and extremely good security. It is built on a hill surrounded by steep, inaccessible slopes and is in the shape of an irregular rectangle. The report analyzes the relationship between legends and folk songs with the latest archaeological discoveries and perspectives that are opening up for new research.

The factors affecting the diffusion properties of hydrogen in palladium copper alloys: Ab initio study

The experiments showed that the addition of copper (Cu) in palladium (Pd) membrane reduces the permeability of hydrogen (H) in Pd, and the permeability of H in body-centered cubic (BCC) PdCu alloy is larger than that in face-centered cubic (FCC) PdCu alloy. The underlying reasons are still not well understood. In the present work, systematical ab initio calculations are carried out to investigate the factors affecting the diffusion properties of H in PdCu alloys. It is found that the lowest diffusion barrier of H with zero-point energy correction in BCC PdCu alloy (0.016 eV) is relatively low than that in FCC PdCu alloy (0.346 eV). The interactions among interstitial H atoms are significantly repulsive in BCC PdCu alloy, while it is attractive in FCC PdCu alloy. The results suggest that it is energetically favorable to form interstitial H cluster in FCC PdCu alloy rather than that in BCC PdCu alloy. The formation of interstitial H clusters impedes the fast movement of H in FCC PdCu alloy. The presence of intrinsic vacancy in FCC PdCu alloy further hinders the migration of H. It is found that the binding strength of vacancy with H in FCC PdCu alloy is much larger than that in BCC PdCu. The stronger the combination of H and vacancy, the greater the obstacle to the movement of H in PdCu alloy. All these results elucidate the experimental phenomena why H penetration ability in FCC PdCu alloy is weaker than that in BCC PdCu alloy.

Effects of rhythmic auditory stimulation on upper-limb movements in patients with Parkinson's disease

IntroductionRhythmic auditory stimulation (RAS) is an effective technique extensively used to alleviate lower-limb bradykinesia in patients with Parkinson's disease (PD). However, RAS effects on upper-limb bradykinesia have not been well studied. This study investigated immediate effects of RAS on upper-limb movements in PD patients and healthy people. MethodsPD patients (n = 23) and age- and gender-matched healthy controls (n = 23) executed left-hand, right-hand, and both-hand movement tasks of the Purdue Pegboard Test when listening to the beats of RAS, including 100%, 110%, and 120% of the baseline tempo, which was fastest movement performance of each participant without the aid of RAS. Sequence of RAS and tasks was randomized for each participant. ResultsPD patients had slower upper-limb movements than did health controls. An interaction was found between RAS and tasks. In both patients and controls and for all task conditions, 120%RAS induced higher scores than did 110% RAS, and the latter induced higher scores than did 100%RAS. In both patients and controls and for all RAS conditions, the right-hand condition induced higher scores than did the left-hand condition, and the latter induced higher scores than did the both-hand condition. ConclusionsRAS was effective in regulating upper-limb movements in PD patients, which may be explained by rich neural connections between auditory and motor cortical areas in humans. Clinical practitioners should consider using RAS in clinical therapy. Future neuroimaging studies are needed to explore neural mechanisms of RAS in PD patients.

Commentary: Is There an "Acquired Idiopathic Head-Shaking Nystagmus?": A Discussion of Mechanisms and Clinical Implications Based on a Case Report.

A commentary on 'Is There an "Acquired Idiopathic Head-Shaking Nystagmus"?-AWe read the paper by Filippopulos FM and his colleagues with great interest. 1 This report described a patient with recurrent episodes of vertigo prompted by fast head movement. As the authors noted, we previously reported a group of patients with recurrent spontaneous vertigo with interictal HSN (BRV-HSN) in the absence of peripheral vestibulopathy as was documented by caloric, head-impulse, or rotatory chair tests. Even though we could not assess HSN in those patients with BRV-HSN during the attacks, the only difference between the BRV-HSN and aiHSN appears to be the absent HSN between the attacks in aiHSN. Given the 1) increased time constants of the HSN and rotatory nystagmus, 2) emergence of the HSN even with a short duration of head-shaking, and 3) good responses to baclofen, we proposed that unstable and asymmetric VSM may be the cause for vertigo and BRV-HSN. 2 Apparently, the characteristics of HSN observed in the patient reported by Filippopulos FM, et al. 1 do not seem to differ from those observed in our patients with BRV-HSN. Thus, the BRV-HSN and aiHSN may lie on the same spectral line due to a common pathomechanism (unstable and asymmetric VSM), rather than distinct disease entities. In addition, the clinical presentation does not escape from the umbrella term of BRV.

Bodyweight, locomotion, and behavioral responses of the naked mole rat (Heterocephalus glaber) to lipopolysaccharide administration

The naked mole rat has unique biologic characteristics that include atypical inflammatory responses. Lipopolysaccharide induces inflammation which triggers brain centers controlling feeding, and behavior to result in “sick animal behavior”. We characterized the bodyweight, locomotor, and other behavioral responses of this rodent to lipopolysaccharide administration. Lipopolysaccharide caused weight losses, which were not prevented by TAK 242. In the open field test, lipopolysaccharide did not depress locomotion, while urination, defecation, and activity freezing were rare. The animals exhibited walling but not rearing and fast backward movements that were unaffected by lipopolysaccharide. Failure to depress locomotion suggests either a unique immunity-brain crosstalk or motor responses/centers that tolerate depressive effects of inflammation. The absence of activity freezing and rarity of urination and defecation suggests that novel environments or lipopolysaccharide do not induce anxiety, or that anxiety is expressed differently in the animal. The absence of rearing could be due to the design of the animal’s locomotor apparatus while fast backward movement could be a mechanism for quick escape from threats in the tunnels of their habitat. Our results elucidate the unique biology of this rodent, which elicits interest in the animal as a model for inflammatory research, although the findings require mechanistic corroborations.

Moving towards intelligent telemedicine: Computer vision measurement of human movement

Background:Telemedicine video consultations are rapidly increasing globally, accelerated by the COVID-19 pandemic. This presents opportunities to use computer vision technologies to augment clinician visual judgement because video cameras are so ubiquitous in personal devices and new techniques, such as DeepLabCut (DLC) can precisely measure human movement from smartphone videos. However, the accuracy of DLC to track human movements in videos obtained from laptop cameras, which have a much lower FPS, has never been investigated; this is a critical gap because patients use laptops for most telemedicine consultations. Objectives:To determine the validity and reliability of DLC applied to laptop videos to measure finger tapping, a validated test of human movement. Method:Sixteen adults completed finger-tapping tests at 0.5 Hz, 1 Hz, 2 Hz, 3 Hz and at maximal speed. Hand movements were recorded simultaneously by a laptop camera at 30 frames per second (FPS) and by Optotrak, a 3D motion analysis system at 250 FPS. Eight DLC neural network architectures (ResNet50, ResNet101, ResNet152, MobileNetV1, MobileNetV2, EfficientNetB0, EfficientNetB3, EfficientNetB6) were applied to the laptop video and extracted movement features were compared to the ground truth Optotrak motion tracking. Results:Over 96% (529/552) of DLC measures were within +/−0.5 Hz of the Optotrak measures. At tapping frequencies >4 Hz, there was progressive decline in accuracy, attributed to motion blur associated with the laptop camera’s low FPS. Computer vision methods hold potential for moving us towards intelligent telemedicine by providing human movement analysis during consultations. However, further developments are required to accurately measure the fastest movements.

Development of Low‐Gain Avalanche Detectors in the Frame of the Acceptor Removal Phenomenon

Low‐gain avalanche detectors (LGAD) suffer from an acceptor removal phenomenon due to irradiation. This acceptor removal phenomenon is investigated in boron, gallium, and indium implanted samples by 4‐point‐probe (4pp) measurements, low‐temperature photoluminescence spectroscopy (LTPL), and secondary ion mass spectrometry (SIMS) before and after irradiation with electrons and protons. Different co‐implantation species are evaluated with respect to their ability to reduce the acceptor removal phenomenon. In case of boron, the beneficial effect is found to be most pronounced for the low‐dose fluorine and high‐dose nitrogen co‐implantation. In case of gallium, the low‐dose implantations of carbon and oxygen are found to be beneficial. For indium, the different co‐implantation species have no beneficial effect. SIMS boron concentration depth profiles measured before and after irradiation show no indication of a fast movement of boron at room temperature. Hence, the discussed BSi–Sii‐defect explanation approach of the acceptor removal phenomenon seems to be more likely than the other discussed Bi–Oi‐defect explanation approach.

Application of Correlation Filter Tracking Algorithm Based on Multiple Color Features in Basketball Motion Capture System

The application of motion capture system in basketball game can intercept the highlights of the game and improve the viewing effect. In order to improve the tracking performance of target tracking algorithm and the efficiency of traditional basketball tracking system, a correlation filtering algorithm combining multiple color features is adopted in this study. A dhcf as algorithm based on multicolor feature is established. The adaptability of traditional KCF algorithm in scene attributes such as rapid target change and illumination change is mainly studied. The success rate of multicolor tracking algorithm can reach 78.2%. At the same time, based on the traditional kernel correlation filter, the algorithm combines the discriminant color descriptor and the direction gradient histogram. The results show that the success rate and accuracy of the algorithm in otb50 are 84.2% and 82.5%, respectively. In addition, excellent tracking performance is reflected in various scene attributes. Therefore, the algorithm can improve the target tracking performance of the traditional kernel correlation filter, especially solving the adaptability of the traditional algorithm in the scene of light change, fast target movement, and so on.

The Sunburst illusion

We report a new visual illusion. When a Mackay Ray figure is observed in paracentral vision or near peripheral vision, a fast but smooth pursuit eye movement produces an impression of bursting of a dazzling light in the center of the figure. We call this effect the Sunburst illusion. We have included movies demonstrating the effects of changing the speed and path of smooth eye movement, saccades, luminance contrast, and color combinations.

From thinking fast to moving fast: motor control of fast limb movements in healthy individuals.

The ability to produce high movement speeds is a crucial factor in human motor performance, from the skilled athlete to someone avoiding a fall. Despite this relevance, there remains a lack of both an integrative brain-to-behavior analysis of these movements and applied studies linking the known dependence on open-loop, central control mechanisms of these movements to their real-world implications, whether in the sports, performance arts, or occupational setting. In this review, we cover factors associated with the planning and performance of fast limb movements, from the generation of the motor command in the brain to the observed motor output. At each level (supraspinal, peripheral, and motor output), the influencing factors are presented and the changes brought by training and fatigue are discussed. The existing evidence of more applied studies relevant to practical aspects of human performance is also discussed. Inconsistencies in the existing literature both in the definitions and findings are highlighted, along with suggestions for further studies on the topic of fast limb movement control. The current heterogeneity in what is considered a fast movement and in experimental protocols makes it difficult to compare findings in the existing literature. We identified the role of the cerebellum in movement prediction and of surround inhibition in motor slowing, as well as the effects of fatigue and training on central motor control, as possible avenues for further research, especially in performance-driven populations.

Relationship between body mass index and postural balance among student of the martial arts club malikussaleh university

Relationship between body mass index and postural balance among student of the martial arts club malikussaleh university. Postural balance is an important component in martial arts. Every player martial art needs fast and strong movements so that the body must be well controlled. Disturbances such as body mass index (BMI) that are not ideal can affect postural stability. The height and shortness or the weight and lightness of a person will affect the location of the center of gravity that later will affect the balance. The purpose of this study is to find out the relationship between body mass index and postural balance among students of the Martial Arts Club Malikussaleh University. This study used a cross-sectional design which was conducted in March 2021 at the Bukit Indah Campus, Malikussaleh University. The sample of this study used total sampling with 49 respondents. Data collection was carried out by measuring body weight, height, static balance with a standing stork test and dynamic balance with a modified bass test of dynamic balance. The results of this study obtained BMI with the highest proportion is normal category, with 31 people (63.3%), while the static balance commonly found in the very good category with 11 people (22.4%), and dynamic balance commonly found in the balanced category with 29 people (59.2 %). The results of the chi-square analysis showed that there was a relationship between BMI with static balance (p = 0.019) and dynamic balance (p = 0.012). This study concludes that there is a relationship between BMI and postural balance among students of Martial Arts Club Malikussaleh University.