Spatial Analysis of Market Linkages in North Carolina Using Threshold Autoregression Models with Variable Transaction Costs

In North Carolina, where soybeans and corn are the two primary crops, the recent increase in the demand for U.S. corn has triggered a shift of farm acreage from soybeans to corn, leading to a rapid rise in prices of both commodities. However, the rate of the price changes, as well as the price level, is significantly different in markets that are located in different parts of the state. This study extends the literature that examines linkages between spatially separated markets by using a threshold autoregressive model with a less restrictive assumption for estimating the transaction cost neutral band -- the band within which trade is not profitable. This generalization allows the neutral band of transactions costs to change according to various external factors, including fuel costs and seasonality. The estimation results indicate that for longer time series data, variable thresholds models statistically outperform the constant thresholds specification, and may provide a better representation of corn and soybean price data. Additionally, impulse response functions that use the asymmetric variable threshold model parameters indicate that the magnitude of the shock as well as the time-to-price-parity-equilibrium in the linked markets may be underestimated if a constant thresholds specification is implemented.threshold autoregression, spatially separated markets, impulse response, neutral band, Demand and Price Analysis, Marketing, Q11, Q13,

Surgeons see anatomical structures faster and more accurately compared to novices: Development of a pattern recognition skill assessment platform

Background This study aimed to identify differences in pattern recognition skill among individuals with varying surgical experience. Methods Participants reviewed laparoscopic cholecystectomy videos of various difficulty, and paused them when the cystic duct or artery was identified to outline each structure on the monitor. Time taken to identify each structure, accuracy and work load, which was assessed using the NASA-Task Load Index (TLX), were compared among the three groups. Results Ten students, ten residents and eight attendings participated in the study. Attendings identified the cystic duct and artery significantly faster and more accurately than students, and identified the cystic artery faster than residents. The NASA-TLX score of attendings was significantly lower than that of students and residents. Conclusions Attendings identified anatomical structures faster, more accurately, and with less effort than students or residents. This platform may be valuable for the assessment and teaching of pattern recognition skill to novice surgeons. Short summary Accurate anatomical recognition is paramount to proceeding safely in surgery. The assessment platform used in this study differentiated recognition skill among individuals with varing surgical experience

Association between Medical Student Grit and United States Medical Licensing Examination Performance

Presented as Themed Oral Presentation at the 2020 IUSM Education Da

Application of Mental Skills Training in Surgery: A Review of Its Effectiveness and Proposed Next Steps

Introduction: Mental skills training, which refers to the teaching of performance enhancement and stress management psychological strategies, may benefit surgeons. Our objective was to review the application of mental skills training in surgery and contrast it to other domains, examine the effectiveness of this approach in enhancing surgical performance and reducing stress, and provide future directions for mental skills training in surgery. Materials and Methods: A systematic literature search of MEDLINE, PubMed, PsycINFO, and ClinicalKey was performed between 1996 and 2016. Keywords included were mental readiness, mental competency, mental skill, mental practice, imagery, mental imagery, mental rehearsal, stress management training, stress coping, mental training, performance enhancement, and surgery. Reviews of mental skills interventions in sport and well-regarded sport psychology textbooks were also reviewed. Primary outcome of interest was the effect of mental skills on surgical performance in the simulated or clinical environment. Results: Of 490 identified abstracts, 28 articles met inclusion criteria and were reviewed. The majority of the literature provides evidence that mental imagery and stress management training programs are effective at enhancing surgical performance and reducing stress. Studies from other disciplines suggest that comprehensive mental skills programs may be more effective than imagery and stress management techniques alone. Conclusions: Given the demonstrated efficacy of mental imagery and stress management training in surgery and the incremental value of comprehensive mental skills curricula used in other domains, a concerted effort should be made to apply comprehensive mental skills curricula during surgical training

A video anchored rating scale leads to high inter-rater reliability of inexperienced and expert raters in the absence of rater training

Background Our objective was to assess the impact of incorporating videos in a behaviorally anchored performance rating scale on the inter-rater reliability (IRR) of expert, intermediate and novice raters. Methods The Intra-corporeal Suturing Assessment Tool (ISAT) was modified to include short video clips demonstrating poor, average, and expert performances. Blinded raters used this tool to assess videos of trainees performing suturing on a porcine model. Three attending surgeons, 4 residents, and 4 novice raters participated; no rater training was provided. The IRR was then compared among rater groups. Results The IRR using the modified ISAT was high at 0.80 (p < 0.001). Ratings were significantly correlated with trainee objective suturing scores for all rater groups (experts: R = 0.84, residents: R = 0.81, and novices: R = 0.69; p < 0.001). Conclusions Incorporating video anchors (to define performance) in the ISAT led to high IRR and enabled novices to achieve similar consistency in their ratings as experts

Effectiveness of a comprehensive mental skills curriculum in enhancing surgical performance: Results of a randomized controlled trial

INTRODUCTION: We hypothesized that the implementation of a novel mental skills curriculum (MSC) during laparoscopic simulator training would improve mental skills and performance, and decrease stress. METHODS: Sixty volunteer novices were randomized into intervention and control groups. All participants received FLS training while the intervention group also participated in the MSC. Skill transfer and retention were assessed on a live porcine model after training and 2 months later, respectively. Performance was assessed using the Test of Performance Strategies-2 (TOPS-2) for mental skills, FLS metrics for laparoscopic performance, and the State Trait Anxiety Inventory (STAI-6) and heart rate (HR) for stress. RESULTS: Fifty-five participants (92%) completed training and the transfer test, and 46 (77%) the retention test. There were no significant differences between groups at baseline. Compared to controls the intervention group significantly improved their mental skill use, demonstrated higher laparoscopic skill improvement during retention, and reported less stress during the transfer test. CONCLUSIONS: The MSC implemented in this study effectively enhanced participants' mental skill use, reduced cognitive stress in the operating room with a small impact on laparoscopic performance

Attentional selectivity, automaticity, and self-efficacy predict simulator-acquired skill transfer to the clinical environment

Introduction Several studies demonstrated that simulator-acquired skill transfer to the operating room is incomplete. Our objective was to identify trainee characteristics that predict the transfer of simulator-acquired skill to the operating room. Methods Trainees completed baseline assessments including intracorporeal suturing (IS) performance, attentional selectivity, self-reported use of mental skills, and self-reported prior clinical and simulated laparoscopic experience and confidence. Residents then followed proficiency-based laparoscopic skills training, and their skill transfer was assessed on a live-anesthetized porcine model. Predictive characteristics for transfer test performance were assessed using multiple linear regression. Results Thirty-eight residents completed the study. Automaticity, attentional selectivity, resident perceived ability with laparoscopy and simulators, and post-training IS performance were predictive of IS performance during the transfer test. Conclusions Promoting automaticity, self-efficacy, and attention selectivity may help improve the transfer of simulator-acquired skill. Mental skills training and training to automaticity may therefore be valuable interventions to achieve this goal

Mental Skills Training Limits the Decay in Operative Technical Skill under Stressful Conditions: Results of a Multisite, Randomized Controlled Study

Background Overwhelming stress in the operating room can lead to decay in operative performance, particularly for residents who lack experience. Mental skills training can minimize deterioration in performance during challenging situations. We hypothesized that residents trained on mental skills would outperform controls under increased stress conditions in the simulated operating room. Methods Residents from Indiana University enrolled voluntarily in this institutional review board–approved study. Residents were stratified according to baseline characteristics and randomized into a mental skills and control group. Both groups trained to proficiency in laparoscopic suturing, but only the mental skills group received mental skills training. After training, technical skill transfer was assessed under regular and stressful conditions on a porcine model. Performance was assessed using an objective suturing score. The Test of Performance Strategies was used to assess the use of mental skills. Data were combined and compared with data that had been collected at Carolinas Healthcare System because residents underwent the same protocol. Results A total of 38 residents completed all study elements. There were no differences in the effects observed between sites. We observed no group differences at baseline. The groups achieved similar technical performance at baseline, posttest, and transfer test under low-stress conditions, but the mental skills group outperformed the control group during the transfer test under high-stress conditions. Conclusion Our comprehensive mental skills curriculum implemented with surgery residents at two institutions was effective at minimizing the deterioration of resident technical performance under stressful conditions compared with controls. These results provide further evidence for the effectiveness of mental skills training to optimize surgery trainees’ technical performance during challenging clinical situations

Architecture and Membrane Interactions of the EGF Receptor

SummaryDimerization-driven activation of the intracellular kinase domains of the epidermal growth factor receptor (EGFR) upon extracellular ligand binding is crucial to cellular pathways regulating proliferation, migration, and differentiation. Inactive EGFR can exist as both monomers and dimers, suggesting that the mechanism regulating EGFR activity may be subtle. The membrane itself may play a role but creates substantial difficulties for structural studies. Our molecular dynamics simulations of membrane-embedded EGFR suggest that, in ligand-bound dimers, the extracellular domains assume conformations favoring dimerization of the transmembrane helices near their N termini, dimerization of the juxtamembrane segments, and formation of asymmetric (active) kinase dimers. In ligand-free dimers, by holding apart the N termini of the transmembrane helices, the extracellular domains instead favor C-terminal dimerization of the transmembrane helices, juxtamembrane segment dissociation and membrane burial, and formation of symmetric (inactive) kinase dimers. Electrostatic interactions of EGFR’s intracellular module with the membrane are critical in maintaining this coupling

Mastering Stress: Mental Skills and Emotional Regulation for Surgical Performance and Life

Mental skills and emotional regulation training are gaining acceptance in surgical education as vital elements of surgeon development. These skills can effectively enhance technical skill development, improve well-being, and promote career longevity. There is evidence emerging in the surgical education literature to support the incorporation of mental skills and emotional regulation training curricula in residency training. In this study, we present the existing evidence supporting the use of this training with high performers to reduce stress and optimize well-being and performance. We also consider the recent research emerging in surgical education that offers validity evidence for use of mental skills training with surgeons. Finally, we provide a framework to guide the incorporation of these skills throughout the career of a surgeon and suggest methods to promote the development of mental skills training efforts nationally