Measuring the Average Peak Timing of Kinematic Variables in Youth and Adolescent Baseball Pitchers.

Background: Previous studies have examined the timing of peak kinematic variables during the pitching cycle in high school, collegiate, and professional pitchers. These same variables have been studied less in younger populations. Purpose: To determine whether youth and adolescent baseball pitchers will experience peaks in certain kinematic variables at different times throughout the pitching cycle compared to professional/collegiate pitchers. Study Design: Cross-sectional, descriptive study. Methods: Twenty-four participants were recruited for testing consisting of five recorded pitches using 3-Dimensional VICON® motion analysis system. The maximum values and timing of the peak kinematic variables were averaged across all trials using VICON Polygon® data analysis software. These values were recorded as percentages of the pitching cycle, defined from foot contact (0%) to ball release (100%). The following variables were examined: shoulder external rotation range of motion, shoulder internal rotation velocity, trunk rotation range of motion, trunk rotation velocity, pelvic rotation velocity, and stride length. Descriptive outcomes were calculated and results were compared to previous studies examining the same variables in collegiate and professional pitchers. Results: Twenty-four male participants (mean age 12.75 years, SD ± 2.02) were included in the study. Mean and standard deviations were identified for peak kinematic variables of shoulder external rotation ROM (158.71°, ±9.32), shoulder internal rotation velocity (92.26 rad/sec, ±19.29), trunk rotation velocity (15.94 rad/sec, ±1.68), trunk rotation ROM (23.57°, ±8.14), and average stride length (81.97% height ±4.57). Additionally, mean and standard deviations of peak kinematic variables were expressed as percentages to reflect when they occurred in the pitching cycle and included trunk rotation ROM (8.45%, ±12.72), pelvic rotation velocity (33.26%, ±16.42), trunk rotation velocity (41.59%, ±9.27), shoulder external rotation ROM (71.34%, ±6.61), and shoulder internal rotation velocity (86.93%, ±6.45). Conclusion: The sequential order of each variable was similar in youth and adolescents in comparison to collegiate and professional pitchers. However, the timing of each variable within the pitching cycle occurred approximately 10% earlier in the younger pitchers. The findings suggest differences in pitching mechanics exist between younger and more experienced populations. Level of Evidence: Level 3.

A lightweight transformer for faster and robust EBSD data collection.

Three dimensional electron back-scattered diffraction (EBSD) microscopy is a critical tool in many applications in materials science, yet its data quality can fluctuate greatly during the arduous collection process, particularly via serial-sectioning. Fortunately, 3D EBSD data is inherently sequential, opening up the opportunity to use transformers, state-of-the-art deep learning architectures that have made breakthroughs in a plethora of domains, for data processing and recovery. To be more robust to errors and accelerate this 3D EBSD data collection, we introduce a two step method that recovers missing slices in an 3D EBSD volume, using an efficient transformer model and a projection algorithm to process the transformer's outputs. Overcoming the computational and practical hurdles of deep learning with scarce high dimensional data, we train this model using only synthetic 3D EBSD data with self-supervision and obtain superior recovery accuracy on real 3D EBSD data, compared to existing methods.

Dynamical-statistical seasonal forecasts of winter and summer precipitation for the Island of Ireland.

Seasonal precipitation forecasting is highly challenging for the northwest fringes of Europe due to complex dynamical drivers. Hybrid dynamical-statistical approaches offer potential to improve forecast skill. Here, hindcasts of mean sea level pressure (MSLP) from two dynamical systems (GloSea5 and SEAS5) are used to derive two distinct sets of indices for forecasting winter (DJF) and summer (JJA) precipitation over lead-times of 1-4 months. These indices provide predictors of seasonal precipitation via a multiple linear regression model (MLR) and an artificial neural network (ANN) applied to four Irish rainfall regions and the Island of Ireland. Forecast skill for each model, lead time, and region was evaluated using the correlation coefficient (r) and mean absolute error (MAE), benchmarked against (a) climatology, (b) bias corrected precipitation hindcasts from both GloSea5 and SEAS5, and (c) a zero-order forecast based on rainfall persistence. The MLR and ANN models produced skilful precipitation forecasts with leads of up to 4 months. In all tests, our hybrid method based on MSLP indices outperformed the three benchmarks (i.e., climatology, bias corrected, and persistence). With correlation coefficients ranging between 0.38 and 0.81 in winter, and between 0.24 and 0.78 in summer, the ANN model outperformed MLR in both seasons in most regions and lead-times. Forecast skill for summer was comparable to that in winter and for some regions/lead times even superior. Our results also show that climatology and persistence performed better than direct use of bias corrected dynamical outputs in most regions and lead-times in terms of MAE. We conclude that the hybrid dynamical-statistical approach developed here-by leveraging useful information about MSLP from dynamical systems-enables more skilful seasonal precipitation forecasts for Ireland, and possibly other locations in western Europe, in both winter and summer.

Transcranial motor-evoked potentials for prediction of postoperative neurologic and motor deficit following surgery for thoracolumbar scoliosis.

Transcranial motor-evoked potentials (TcMEPs) are used to monitor the descending motor pathway during scoliosis surgery. By comparing potentials before and after correction, surgeons may prevent postoperative functional loss in distal muscles. There is currently no consensus as to which muscles should be monitored. The purpose of this study is to determine the least invasive monitoring protocol with the best localization of potential neurologic deficit. A retrospective review of 125 patients with TcMEP monitoring during surgery for thoracolumbar scoliosis between 2008 and 2015 was conducted. 18 patients had postoperative neurologic consult due to deficit. The remaining 107 patients were a consecutive cohort without postoperative neurologic consult. TcMEPs were recorded from vastus lateralis (VL), tibialis anterior (TA), peroneus longus (PL), adductor hallucis (AH) and abductor pollicis brevis (APB) bilaterally. The effectiveness of each muscle combination was evaluated independently and then compared to other combinations using Akaike Information Criterion (AIC). Monitoring of VL, TA, PL, and AH yielded sensitivity of 77.8% and specificity of 92.5% (AIC=66.7). Monitoring of TA, PL and AH yielded sensitivity of 77.8% and specificity of 94.4% (AIC=62.4). Monitoring of VL, TA and PL yielded sensitivity of 72.2% and specificity of 93.5% (AIC=70.1). Monitoring of TA and PL yielded sensitivity of 72.2% and specificity of 96.3% (AIC=63.9). TcMEP monitoring of TA, PL, and AH provided the highest sensitivity and specificity and best predictive power for postoperative lower extremity weakness.

A randomized crossover study of the effects of lidocaine on motor- and sensory-evoked potentials during spinal surgery.

BACKGROUND CONTEXT: Lidocaine has emerged as a useful adjuvant anesthetic agent for cases requiring intraoperative monitoring of motor-evoked potentials (MEPs) and somatosensory-evoked potentials (SSEPs). A previous retrospective study suggested that lidocaine could be used as a component of propofol-based intravenous anesthesia without adversely affecting MEP or SSEP monitoring, but did not address the effect of the addition of lidocaine on the MEP and SSEP signals of individual patients. PURPOSE: The purpose of this study was to examine the intrapatient effects of the addition of lidocaine to balanced anesthesia on MEPs and SSEPs during multilevel posterior spinal fusion. STUDY DESIGN: This is a prospective, two-treatment, two-period crossover randomized controlled trial with a blinded primary outcome assessment. PATIENT SAMPLE: Forty patients undergoing multilevel posterior spinal fusion were studied. OUTCOME MEASURES: The primary outcome measures were MEP voltage thresholds and SSEP amplitudes. Secondary outcome measures included isoflurane concentrations and hemodynamic parameters. METHODS: Each participant received two anesthetic treatments (propofol 50 mcg/kg/h and propofol 25 mcg/kg/h+lidocaine 1 mg/kg/h) along with isoflurane, ketamine, and diazepam. In this manner, each patient served as his or her own control. The order of administration of the two treatments was determined randomly. RESULTS: There were no significant within-patient differences between MEP threshold voltages or SSEP amplitudes during the two anesthetic treatments. CONCLUSIONS: Lidocaine may be used as a component of balanced anesthesia during multilevel spinal fusions without adversely affecting the monitoring of SSEPs or MEPs in individual patients.