Ball Placement Research Articles

Investigation on improving soldering reliability of large-scale LCCC devices with high-lead solder ball materials

Abstract Leadless Ceramic Chip Carrier (LCCC) is commonly used in high-density electronic packaging PCB boards. Due to the different thermal expansion of materials, the solder joints of LCCC devices are prone to stress and cracking after assembly, which leads to the failure of LCCC devices’ electrical performance. In this paper, the advantages and disadvantages of four solutions were analysed, and comprehensively considered the use of ball planting to alleviate thermal mismatch stress. After experimental verification, the thermal mismatch between the LCCC devices and PCB results in a lifespan of less than 200 cycles for direct assembly of the LCCC devices. Planting balls at the bottom of LCCC devices and soldering can effectively increase the lifespan of solder joints and improve product reliability. By analysing the SMT process, the bottom high-lead ball placement of LCCC devices was implemented, and environmental testing was conducted using temperature shock testing to demonstrate that bottom ball placement can extend solder joint life and improve reliability. This study provides a reliable soldering method for large-scale LCCC devices and provides a basis for improving LCCC reliability.

The effects of simulated monocular and binocular vision impairment on football penalty kick performance.

Sports performance is relatively robust under high levels of binocular blur. However, the limited research studies investigating monocular impairments has shown it has a larger impact on sport performance. This research study is relevant for classification in sports for athletes with vision impairment (VI), where visual acuity (VA) from the better eye is used during classification. Across two experiments, we aimed to establish the point at which binocular and monocular impairments affected performance in a football penalty kick (PK) through simulating varying severities of degraded VA and contrast sensitivity (CS) in active football players. In experiment one, 25 footballers performed PKs as VA and CS were systematically decreased in both eyes, and in one condition, visual field (VF) was reduced. The most severe VA/CS condition and reduced VF significantly impacted outcome, ball velocity and placement (ball kicked closer to the centre of the goal) (p<0.05). In experiment two, 29 different footballers performed PKs as VA and CS of only the dominant eye were systematically decreased and in one condition the dominant eye was occluded, and participants viewed their environment through the non-dominant eye (monocular viewing). No differences were observed when assessing monocular impairments influence on outcome, velocity and ball placement. PKs have a high resilience to VI, but binocular impairment has a more immediate effect, suggesting binocular measures should be used in classification processes in football.

Playing style of women and men elite table tennis players

ABSTRACT Background: Match and notational analysis are well-recognised methods to collect important information about technical-tactical indicators in racket sports (shot, footwork, ball placement, and outcome). The purpose of this study was to analyse the principal indicators, with a special focus on comparing the playing style of women and men high-level players. Methods: twenty matches played by 40 women, and twenty matches played by 40 men were analysed in slow motion by an expert coach. All the players were in the top 111(W) and 120 (M) positions of the ITTF world ranking; Results: women play more shots/rallies and shots/games compared to men. The most used shots are Top forehand and Serve for both groups. Women also prefer to play backhand block and drive. Conversely, men prefer to counterattack with forehand Top C Top. One step is often used by women, and they also prefer to hit the ball without performing any step. Conversely, men perform crossover and pivot footwork. Serves are generally directed to close-to-the-net areas, and the following shots are typically directed to the backhand corner during the rallies. Conclusions: Women showed a specific distribution of technical indicators with respect to men players, suggesting sex-specific training sessions.

Muscular Endurance and Strength as Predominant Factors on Spike among Young Volleyball Athletes

Most of physiological investigation in volleyball studies only discussed which body part is dominant when someone doing spike. There are still few studies to explore in more detail on what muscle works and roles of muscle is so crucial. This study aims to determine which part of the muscle has a more specific effect during spike movements. This study uses a quantitative descriptive method, participants in this study were female and male adolescent athletes obtained 42 participants, divided into 20 males and 22 females. Data on muscle endurance and strength were obtained by measuring the leg and back dynamometer, while the spike hit results collected from The Volleyball Test Skills for Smasher and performance were obtained using observation using a range of points 1-4, which is based on five spike phases: Initial Attitude, Initial Motion, Contact Motion, Follow through Motion, and Ball Placement. Data analysis used ANOVA test and simple regression. The results showed that the performance was significantly increased by the strength of the back muscles (p = 0.005 &lt; 0.05) and abdominal muscles (p = 0.012 &lt; 0.05), while the other components were supportive but not significant. Likewise, the strength of the inner leg muscles (p = 0.010 &lt; 0.05) which has a very significant level of influence (p &lt; 0.01) on the spike results. Strengthening back muscle and abdominal muscle endurance need to be the focus of the training program for young volleyball athletes because they are needed during spike movement and inner leg muscle strength is needed to obtain maximum spike jumps. Keywords: spike; endurance; strength; muscle; young athletes; volleyball

Recovery of kicking kinematics and performance following repeated high-intensity running bouts in the heat: Can a rapid local cooling intervention help young soccer players?

ABSTRACT The effects of a cooling strategy following repeated high-intensity running (RHIR) on soccer kicking performance in a hot environment (>30ºC) were investigated in youth soccer players. Fifteen academy under-17 players participated. In Experiment 1, players completed an all-out RHIR protocol (10×30 m, with 30s intervals). In Experiment 2 (cross-over design), participants performed this running protocol under two conditions: (1) following RHIR 5 minutes of cooling where ice packs were applied to the quadriceps/hamstrings, (2) a control condition involving passive resting. Perceptual measures [ratings of perceived exertion (RPE), pain and recovery], thigh temperature and kick-derived video three-dimensional kinematics (lower limb) and performance (ball speed and two-dimensional placement indices) were collected at baseline, post-exercise and intervention. In Experiment 1, RHIR led to small-to-large impairments (p < 0.03;d = −0.42–-1.83) across perceptual, kinematic and performance measures. In experiment 2, RPE (p < 0.01; Kendall’s W = 0.30) and mean radial error (p = 0.057; η2 = 0.234) increased only post-control. Significant small declines in ball speed were also observed post-control (p < 0.05; d = 0.35). Post-intervention foot centre-of-mass velocity was moderately faster in the cooling compared to control condition (p = 0.04; d = 0.60). In youth soccer players, a short cooling period was beneficial in counteracting declines in kicking performance, in particular ball placement, following intense running activity in the heat.

Virtual Mouse by Means of Manual Gestures

The main aim to perform the mouse cursor operations and scrolling function and also move the cursor. A professional webcam, novel process of managing mouse click was developed. The integration of different efforts would include changing keypad elements, integrating more keys, or shifting the monitoring ball's placement. However, they recommend that the hardware design be altered. The proposed approach solves present inadequacies as well as utilized of a hardware mouse, but also numerous motions cause injury in the palms. It should be predicated on a visualization impact of motion, accompanied by artificial intelligence technology, image classification, and motion tracking, to regulate mouse tasks (left and right-clicking, double- clicking, and scrolling), as well as Machine Cognitive approach to obtain a greater virtual touchpad to the current systems. A camera should be used to capture palm motions.

A Longitudinal Study of Changes in the Shot Characteristics of Women Table Tennis Players: Analysis of the Olympic Semifinals and Finals of Women's Singles.

This study aims to evaluate the changes in shot characteristics of elite women table tennis players through the longitudinal analysis of women's singles finals and semifinals from 2004 to 2021 Olympic Games. A total of 13 games were selected, and the stroke position, stroke type, ball placement, and stroke efficacy of 5,877 shots were analyzed using the notational analysis method. A chi-square test was used to test whether the shot characteristics had changed between game years, and the adjusted residual was calculated to judge these changes. In the four dimensions, namely, stroke position, stroke type, ball placement, and stroke efficacy, the shot characteristics of women table tennis players have changed with the year of the Olympic Games. The backhand stroke position has an upward trend from 55.0 to 58.1%, and the type of flip stroke has a downward trend from 7.6 to 2.1%. The ball placements of forehand and middle long have two fluctuations first rising from 11.2 to 12.7% and 20.3 to 23.7% and then falling from 12.7 to 5.3% and 23.7 to 16.0%. Moreover, backhand long is being increasingly used. In the year of equipment change, the proportion of neutral stroke increases from 40.0 to 61.5%. Once the players have become adapted to the equipment, the proportion of neutral stroke decreases from 61.5 to 48.5%. The development trend of women table tennis players is that the extreme stroke will be further increasingly used. Results suggest that elite women table tennis coaches and players should focus on the technical training in the forehand and backhand positions, strengthen the practice of topspin and block, and pay attention to the backhand long landing area. Women's table tennis coaches and players also need to pay close attention to the possible impact of changes in rules and equipment and carry out targeted training in advance to minimize the impact on the stroke efficacy of players.

Low sleep quality and morningness-eveningness scale score may impair ball placement but not kicking velocity in youth academy soccer players

ABSTRACT Purpose: The current study examined the possible relationships between one-off single night sleep metrics and subsequent kicking performance in a youth soccer context. Methods: Twenty-eight under-17 academy players (15.9 ± 0.8 years-old) completed a kick testing protocol consisting in 20 attempts, 18 m from the goal and against a goalkeeper. Four digital video cameras (240 Hz) allowed to determine 3-D approach run, lower limb and ball velocities. Two additional cameras (60 Hz) were used to calculate 2-D mean radial error, bivariate variable error and accuracy. Over 24 h prior to testing, players were monitored by wrist actigraphy to determine their sleep indices. Self-reported sleep quality, sleepiness and chronotype scale scores (Horne and Östberg morningness-eveningness questionnaire) were also collected immediately before kicking experiment. Results: Multiple linear regressions indicated that wake up time and chronotype contributed to 40% of mean radial error. Self-reported sleep quality influenced respectively on 19% and 24% of accuracy and bivariate variable error variances. Taken together self-reported sleep quality and wake up time explained 33% of accuracy (all p < 0.05). Indicators of kicking velocity were non-significantly correlated with sleep (r = −0.30–0.29; p > 0.05). Conclusion: One-off sleep measures showed some sensitivity to acutely detect inter-individual oscillations in kicking performance. Low perceived sleep quality, later wake up time and a chronotype toward evening preference seem either related to immediately subsequent worst ability of ball placement when kicking. Monitoring sleep-wake transition and perceived sleep quality may be important to help prevent acute performance declines in targeting the goal during kick attempts from the edge of penalty area.

Utilizing deep neural networks and electroencephalogram for objective evaluation of surgeon’s distraction during robot-assisted surgery

ObjectiveTo develop an algorithm for objective evaluation of distraction of surgeons during robot-assisted surgery (RAS). Materials and methodsElectroencephalogram (EEG) of 22 medical students was recorded while performing five key tasks on the robotic surgical simulator: Instrument Control, Ball Placement, Spatial Control II, Fourth Arm Tissue Retraction, and Hands-on Surgical Training Tasks. All students completed the Surgery Task Load Index (SURG-TLX), which includes one domain for subjective assessment of distraction (scale: 1–20). Scores were divided into low (score 1–6, subjective label: 1), intermediate (score 7–12, subjective label: 2), and high distraction (score 13–20, subjective label: 3). These cut-off values were arbitrarily considered based on a verbal assessment of participants and experienced surgeons. A Deep Convolutional Neural Network (CNN) algorithm was trained utilizing EEG recordings from the medical students and used to classify their distraction levels. The accuracy of our method was determined by comparing the subjective distraction scores on SURG-TLX and the results from the proposed classification algorithm. Also, Pearson correlation was utilized to assess the relationship between performance scores (generated by the simulator) and distraction (Subjective assessment scores). ResultsThe proposed end-to-end model classified distraction into low, intermediate, and high with 94%, 89%, and 95% accuracy, respectively. We found a significant negative correlation (r = -0.21; p = 0.003) between performance and SURG-TLX distraction scores. ConclusionsHerein we report, to our knowledge, the first objective method to assess and quantify distraction while performing robotic surgical tasks on the robotic simulator, which may improve patient safety. Validation in the clinical setting is required.

RSOB Shorting Defect Resolution through Looping Optimization and Ball Placement at Wirebond Process

Wirebonding process is one of the most challenging assembly manufacturing process in semiconductor packaging industry. This paper discussed the wirebonding challenge and the solution to resolve the wire to die shorting on reverse stitch on ball (RSOB) and prevent irregular looping height for the substrate land grid array (LGA) device. Comprehensive parameter optimization was done particularly on the wirebond looping to ensure that no wire depression and no capillary hitting would occur wirebonding setup. Ultimately, the optimized wirebonding parameter prevented the occurrence of looping issues during the lot process. For future works, the configuration and technique could be applied on packages with similar situation.

The potential impact from glenohumeral internal rotation deficit to the knee kinematics in baseball pitchers: A case-control study.

A recent study suggested that baseball pitchers with glenohumeral internal rotation deficit (GIRD) may tend to use trunk rotation as compensation to adjust ball placement, which may lead to subsequent counter movement at the knee of the leading leg.This study aims to investigate the kinematic characteristics of the counter movements between the femur and the tibia (knee torsion), from the landing of the leading leg until the follow-through phase, during throwing between pitchers with and without GIRD at the dominant arm.This is a case-control study. Twenty-one senior high school baseball pitchers were recruited in this study. The glenohumeral internal and external rotation, hip internal and external rotation of all participants were measured. Eight pitchers without GIRD and 13 pitchers with GIRD were enrolled into the control group and experiment group, respectively. The maximal angular movement between the femur and the tibia (knee torsion) of the leading leg was measured, using The Zebris 3D (Zebris Medizintechnik GmbH, Isny, Germany) motion analysis system, in the interval from the landing until the follow-through phase during pitching a fastball to the bottom-outside corner with their dominant arm.The results showed that the maximal knee torsion of the leading leg in the experimental group (13.67 ± 0.9 degrees) was significantly greater than the control group (4.25 ± 1.369 degrees) (P < .05).Pitchers with GIRD had greater counter movement in the knee joint than pitchers without GIRD.

Medical student experience with robot-assisted surgery after limited laparoscopy exposure

The purpose of the study was to evaluate the objective and subjective experience of medical students completing robotic surgery tasks after limited laparoscopy exposure. Twenty-three medical students without previous laparoscopy and robotic surgery experience self-enrolled into 0 min (n = 11), 20 min (n = 6), and 40 min (n = 6) laparoscopy training groups. Subjects completed rope passing and ball placement tasks on a laparoscopy trainer before repeating similar tasks on the Senhance Surgical System, a robot-assisted digital laparoscopy device. Videos were recorded to evaluate objective measures including time, completion rate, clutch use, out of view instruments, ball drops, and manual adjustments. The NASA-TLX survey was administered to assess subjective experience using workload and task demand measures. There were no statistically significant differences in objective performance between the groups (p > 0.05). Subjects who completed laparoscopy training reported higher workloads, but these differences were not statistically significant (p > 0.05). NASA-TLX workload was correlated with time performance on Pearson and Spearman tests (r = 0.623, rho = 0.681, p < 0.01). Initial experience of medical students with robot-assisted surgery did not differ significantly after limited laparoscopy exposure.

Vibration-Damping technology in tennis racquets: Effects on vibration transfer to the arm, muscle fatigue and tennis performance

High vibration transfer from a tennis racquet to the player may cause discomfort, and is hypothesized to influence performance and the onset of muscle fatigue. This study examined a racquet with a novel vibration damping technology (VDT) designed to mitigate frame vibration. Racquet vibration, post-impact vibration transfer to the player, arm electromyographic activity and tennis performance were compared to a non-VDT racquet. Nineteen young adult, competitive tennis players hit forehands and serves until near exhaustion on two days; using one of the two racquets each day. Tri-axial accelerometers mounted to racquet shaft, hand and forearm recorded vibration behaviour. Surface electromyography recorded activity of five arm muscles. In comparison to the non-VDT racquet, the VDT design showed: 1) A significantly lower mean normalised acceleration signal energy at the racquet during unfatigued play (−40%) and at near exhaustion (−34%), which corresponded to a 20–25% lower signal energy at the hand. 2) Reduced signs of arm muscle fatigue at near exhaustion, which was most pronounced in biceps and wrist extensors. 3) Players hit 11% more forehands and placed 40% more hits in the target area at near exhaustion. Conclusion: VDT effectively reduces racquet vibration. Initial evidence indicates that it may delay muscle fatigue, which was associated with increased ball placement accuracy.

Self-Control in Aiming Supports Coping With Psychological Pressure in Soccer Penalty Kicks

This study addressed the question whether coaches better allow athletes to self-control their decisions when under pressure or whether to impose a decision upon them. To this end, an experiment was conducted that manipulated the soccer kickers’ degree of control in decision-making. Two groups of elite under-19 soccer players (n = 18) took penalty kicks in a self-controlled (i.e., kickers themselves decided to which side to direct the ball) and an externally controlled condition (i.e., the decision to which side to direct the ball was imposed upon the kickers). One group performed the penalty kick under psychological pressure (i.e., the present coaching staff assessed their performance), while the second group performed without pressure. Just before and after performing the kicks, CSAI-2 was used to measure cognitive and somatic anxiety and self-confidence. Further, the number of goals scored, ball placement and speed, and the duration of preparatory and performatory behaviors were determined. The results verified increased levels of cognitive and somatic anxiety after performing the kicks in the pressured group compared to the no-pressure group. In addition, degree of self-control affected the participants’ performance, particularly in the pressured group. They scored more goals and placed the kicks higher in the self-controlled than in the externally-controlled condition. Participants also took more time preparing and performing the run-up in the self-controlled condition. Findings indicate that increased self-control helps coping with the debilitating effects of pressure and can counter performance deteriorations. The findings are discussed within the framework of self-control theories, and recommendations for practitioners and athletes are made.

In Vivo Protocol of Controlled Subconcussive Head Impacts for the Validation of Field Study Data.

Subconcussive hits pose a threat to neuronal health as they have shown to induce neuronal structural damage and functional impairment without causing outward symptomology and appear to be a key contributor to an irreversible neurodegenerative disease, chronic traumatic encephalopathy (CTE). In addition, athletes can incur more than 1,000 of these hits per season. The subconcussive soccer heading model (SSHM) is a relevant, reproducible, and leading method of isolating and examining the effects of these subconcussive head impacts. By controlling variables such as ball traveling speed, the frequency of impacts, interval, ball placement to the head, as well as by measuring head impact magnitude, the SSHM provides the scientific community with a superior avenue of investigating the acute subconcussive effects on neuronal health. In this paper, we demonstrate the utility of SSHM in studying a time-course expression of neurofilament-light polypeptide (NF-L) in plasma in a repeated measures fashion. NF-L is an axonal injury marker that has previously been shown to be elevated in boxers and football players following subconcussive head trauma. Thirty-four adult aged soccer players were recruited and randomly assigned to either a soccer heading (n = 18) or kicking (n = 16) group. The heading group executed 10 headers with soccer balls projected at a velocity of 25 mph over 10 min. The kicking group followed the same protocol with 10 kicks. Plasma samples were obtained before and at 0 h, 2 h, and 24 h after heading/kicking and assessed for NF-L expressions. The heading group showed a gradual increase in plasma NF-L expression and peaked at 24 h after the heading protocol, whereas the kicking group remained consistent across the time points. These results confirmed the NF-L data from clinical field studies, encouraging the use of SSHM to validate clinical subconcussion data.

Reproducibility and Validity of a Stroke Effectiveness Test in Table Tennis Based on the Temporal Game Structure.

Purpose: This study aimed to develop a stroke effectiveness test in table tennis based on the temporal game structure to assess the ball speed and ball placement of the players, with a purpose to analyze its reproducibility and validity.Methods: Nineteen male table tennis players participated in this study. The test was performed twice during the first session and once during the second session to assess the intrasession and intersession reproducibility, respectively. Moreover, the test was examined on its ability to discriminate between regional (n = 10) and local performance-level (n = 9) players and on the relationship between the test results and the table tennis performance to assess the discriminant and concurrent validity, respectively. In general, the test consisted of 11 simulated rallies of 2–5 balls with the effort and rest ratio of 0.5, and focused on attack with offensive strokes at defensive balls delivered by a robot randomly between the left and right positions on the table.Results: Ball speed, ball placement, and ball speed-ball placement index showed satisfactory reliability (ICC range 0.78–0.96, P < 0.05) and agreement (CV range 2.7–16.2%) outcomes. Additionally, the Bland–Altman plots show the systematic error of the analyses closer to 0, and that most values were within the limits of agreements. Concerning validity analyses, regional players had higher scores of ball placement (+51.3%; P = 0.01, ES = 1.33) and ball speed-ball placement index (+56.1%; P = 0.0009, ES = 1.87) as well as made fewer errors (-25.4%; P = 0.017, ES = 1.20) than local players. Moreover, ball placement (r = -0.79, P = 0.04), ball speed-ball placement index (r = -0.78, P = 0.04), and percentage error (r = 0.88, P = 0.01) presented a strong and significant correlation with table tennis performance. However, ball speed was slightly different between the regional than local players (+1.7%; P = 0.78, ES = 0.13) and this variable was not related to table tennis performance (r = 0.32, P = 0.49).Conclusion: Our findings show evidences that the test is reproducible. Moreover, discriminant and concurrent validity are confirmed for ball placement and ball speed-ball placement index.

Using improved simulated anneal arithmetic to improve semiconductor packaging ball placement process capability

This study used improved simulated annealing arithmetic to improve the semiconductor packaging ball placement process capability. The simulated annealing computing process was combined with an artificial neural network, Metropolis algorithm, and sequential Gaussian simulation. Grey relation analysis was used as the target value, which is intended to obtain the optimum parameter design of process capability. The results showed that the substrate design-Pad Open is 0.30 mm ball size, 0.275 mm Pad open, Profile type B, maximum temperature 236 (°C), solder melting time 53 (s), preheating temperature 176 (°C), and a solder ball component, as SAC405 can result in a parameter design for optimal solder ball shear strength of Cpk = 2.38 and [Formula: see text]. This optimum parameter design process is better than other methods, and it reduces the cost waste of extra defectives.

Effective strategies at the ruck in men’s and women’s World Rugby Sevens Series

Despite the growth of research on rugby sevens since its inclusion into the 2016 Olympic Games, some performance aspects of the game remain in their infancy. The ruck is one such area that has had little examination. The aim of this research was to examine the relationships between ruck actions and ruck success. A series of men’s (N = 2521) and women’s (N = 1474) rucks were coded from a sample of men’s (N = 117) and women’s games (N = 65) played within the World Rugby Sevens Series in 2014. Both attacking and defensive ruck actions were analysed. Variables included player numbers in the ruck, the actions of the first players to the ruck, ball placement from the tackled player, the body height, weight distribution and position of the attacking player in the ruck. Chi squared analysis identified that one versus one rucks were most commonly formed. If an attacking player arrived first, then there was a greater chance of maintaining possession compared with the first arrival being from the defensive side (p <...

PD41-08 SKILL ACQUISITION AND ITS RETENTION AFTER SIMULATION-BASED PRACTICE DURING ROBOT-ASSISTED SURGERY: CAN FUNCTIONAL BRAIN STATES HELP US FORGE FORWARD?

You have accessJournal of UrologySurgical Technology & Simulation: Training & Skills Assessment II1 Apr 2017PD41-08 SKILL ACQUISITION AND ITS RETENTION AFTER SIMULATION-BASED PRACTICE DURING ROBOT-ASSISTED SURGERY: CAN FUNCTIONAL BRAIN STATES HELP US FORGE FORWARD? Somayeh Shafiei, Thomas Fiorica, Ahmed Hussein, Youssef Ahmed, Sarah Muldoon, and Khurshid Guru Somayeh ShafieiSomayeh Shafiei More articles by this author , Thomas FioricaThomas Fiorica More articles by this author , Ahmed HusseinAhmed Hussein More articles by this author , Youssef AhmedYoussef Ahmed More articles by this author , Sarah MuldoonSarah Muldoon More articles by this author , and Khurshid GuruKhurshid Guru More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.1887AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Patient safety is fundamental to surgical practice and it is critical to ensure surgical training and competence. Little has been published on brain cognitive states during learning and retention of basic Robot-Assisted Surgical skills. We sought to evaluate the feasibility of utilizing a novel brain functional states to evaluate surgical competency. METHODS 27 medical students were evaluated while performing four key tasks of the validated Fundamental Skills of Robot Surgery (FSRS) Curriculum and one advanced surgical module - the Hands-on Surgical Training (HoST) over six sessions, utilizing the robotic Surgery Simulator (RoSS). The four FSRS tasks evaluated were - Instrument Control Task, Ball Placement Task, Spatial Control II Task, Threading string through a series of hoops and 4th Arm Tissue Retraction. Tool -based metrics were assessed and recorded by RoSS. Brain states are extracted using the pairwise phase synchronization between EEG channels and are presented as functional brain networks. The functional brain networks are then quantified using network statistics, and spectral density of signals for all channels (mental workload). RESULTS The average mental workload initially increases before significantly decreasing across sessions(Fig 1). This trend is also observed in functional brain states during the four tool-based metrics, as integration and segregation features increase at the beginning of learning and later decrease (Fig 2). We observed significant correlations between brain state and tool-based metrics (RoSS), while performing HOST task, where brain states do not correlate. CONCLUSIONS We report to our knowledge, the first study that evaluates brain states during skill acquisition and learning after simulation-based training. Various brain areas are functionally activated and integrated while acquiring new skills but these interactions decrease after preliminary learning. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e810 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Somayeh Shafiei More articles by this author Thomas Fiorica More articles by this author Ahmed Hussein More articles by this author Youssef Ahmed More articles by this author Sarah Muldoon More articles by this author Khurshid Guru More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Assessment of Accuracy of Marker Ball Placement in Pre-operative Templating for Total Hip Arthroplasty

We report the accuracy of positioning of the calibration ball in the process of pre-operative templating for total hip arthroplasty (THA). The ball should be placed in the coronal plane of the hip to provide suitable accuracy. We reviewed 112 post-operative THA radiographs where a calibration ball had been placed. We templated the femoral head size of the implant after calibrating the templating system from the ball. The calibrated femoral head diameter was compared to the known prosthetic head size. A percentage error was calculated. Overall, incorrect placement of the calibration ball resulted in a mean percentage error in templating of 6.8% (median 5.7%; range 0–26%). Such error carries implications with the templating process and may result in incorrect component sizes, leg lengths and offset.