Modified delphi investigation of exercise science in physical education teacher education

As physical education teacher educators experiment with alternative pedagogical approaches to bridge the gap between subdisciplinary theory and professional practice, the need for enhanced multi-disciplinary research and communication continues. The purpose of this study was to determine the critical exercise science competencies, and associated instructional methods, that are recommended for inclusion in the physical education teacher education undergraduate curriculum. An initial list of theoretical and applied exercise science competencies was constructed using the knowledge, skills, and abilities recommended by the American College of Sports Medicine for individuals working in the field of exercise science. The two-round, modified Delphi procedure involved the repeated circulation of this questionnaire to a small panel of content experts. Experts in the field of physical education, including exercise science specialists, physical education teacher educators, and physical education teachers, were sampled to determine which theoretical and applied exercise science competencies are critical for the preparation of prospective physical educators. The Delphi panel members were required to rate each questionnaire item in terms of its theoretical importance and pedagogical relevance using a five-point Likert scale. The data collected during the second round of questioning were employed to provide a final measure of consensus regarding the critical strength of each exercise science competency. An item had to meet the following criteria in order to be considered of both critical importance and relevance: (a) the item received a mean rating of at least four or higher in the areas of importance and relevance; and (b) the item received at least 75% of all individual ratings at the four level or higher. Any item that failed to meet these criteria was considered to be non-critical. The Delphi panel members were also asked to complete an addendum survey concerning their recommendations regarding the four most effective instructional methods for the delivery of exercise science to prospective physical education teachers. The results of this scholarly process, which includes a final list of recommended exercise science competencies and instructional methods, have provided a conceptual framework upon which physical education teacher educators can make future curricular decisions in the area of exercise science

Rare case of gastropericardial fistula after Roux-en-Y gastric bypass

Abstract"Roux-en-Y gastric bypass (RYGB) is a widely used surgery in the management of obesity. Common late complications of RYGB include: Anastomotic stricture, small bowel obstruction, internal hernia, dumping syndrome, cholelithiasis, malnutrition, marginal ulceration, gastro-gastric fistula. Gastropericardial fistulas are an extremely rare but lifethreatening late complication. [less than] 70 cases in modern literature from review in 2016. Mean time of presentation 84 months after surgery (median 60 months). Prior operative risk factors include open or laparoscopic Nissen fundoplication, esophagectomy, hiatal hernia repair, laparoscopic gastric banding and RYGB."--Introduction

Dust masses of disks around 8 Brown Dwarfs and Very Low-Mass Stars in Upper Sco OB1 and Ophiuchus

We present the results of ALMA band 7 observations of dust and CO gas in the disks around 7 objects with spectral types ranging between M5.5 and M7.5 in Upper Scorpius OB1, and one M3 star in Ophiuchus. We detect unresolved continuum emission in all but one source, and the $^{12}$CO J=3-2 line in two sources. We constrain the dust and gas content of these systems using a grid of models calculated with the radiative transfer code MCFOST, and find disk dust masses between 0.1 and 1 M$_\oplus$, suggesting that the stellar mass / disk mass correlation can be extrapolated for brown dwarfs with masses as low as 0.05 M$_\odot$. The one disk in Upper Sco in which we detect CO emission, 2MASS J15555600, is also the disk with warmest inner disk as traced by its H - [4.5] photometric color. Using our radiative transfer grid, we extend the correlation between stellar luminosity and mass-averaged disk dust temperature originally derived for stellar mass objects to the brown dwarf regime to $\langle T_{dust} \rangle \approx 22 (L_{*} /L_{\odot})^{0.16} K$, applicable to spectral types of M5 and later. This is slightly shallower than the relation for earlier spectral type objects and yields warmer low-mass disks. The two prescriptions cross at 0.27 L$_\odot$, corresponding to masses between 0.1 and 0.2 M$_\odot$ depending on age.Comment: 9 pages,6 figures, accepted to ApJ on 26/01/201

Player retention in league of legends: A study using survival analysis

© 2018 ACM. Multi-player online esports games are designed for extended durations of play, requiring substantial experience to master. Furthermore, esports game revenues are increasingly driven by in-game purchases. For esports companies, the trends in players leaving their games therefore not only provide information about potential problems in the user experience, but also impacts revenue. Being able to predict when players are about to leave the game-churn prediction-is therefore an important solution for companies in the rapidly growing esports sector, as this allows them to take action to remedy churn problems. The objective of the work presented here is to understand the impact of specific behavioral characteristics on the likelihood of a player continuing to play the esports title League of Legends. Here, a solution to the problem is presented based on the application of survival analysis, using Mixed Effects Cox Regression, to predict player churn. Survival Analysis forms a useful approach for the churn prediction problem as it provides rates as well as an assessment of the characteristics of players who are at risk of leaving the game. Hazard rates are also presented for the leading indicators, with results showing that duration between matches played is a strong indicator of potential churn

Cross-Entropy Method for Design and Optimization of Pixelated Metasurfaces

© 2013 IEEE. Electromagnetic metasurfaces are planar two-dimensional metamaterials, typically of subwavelength thickness. Unit cell elements of different shapes have been widely explored, including electric and magnetic dipoles, patches, arbitrary geometries and pixelated surfaces. Although pixelated metasurfaces have a great advantage of geometric versatility, their design and analysis requires algorithmic approach. One of the techniques for their design is via evolutionary simulation-driven optimization. Since full-wave electromagnetic simulations are time-consuming, optimization methods with fast convergence properties are preferable. In this article, we demonstrate the application of the cross-entropy optimization method to design of artificial magnetic conductors (AMCs) and thin printed phase shifters. Single-frequency AMCs at 10 GHz (X band) and dual-frequency AMCs at 8 and 12 GHz (X and Ku band) were produced that are more manufacturing-friendly, and thus cost effective, than previously reported AMCs. We also show that phase-shifting unit cells with transmission magnitudes over 0.9 (linear) can be designed using the proposed optimization technique. Other potential applications of these unit cells are in phase-correcting and beam-steering metasurfaces

Two-photon quantum walks in an elliptical direct-write waveguide array

Integrated optics provides an ideal test bed for the emulation of quantum systems via continuous-time quantum walks. Here we study the evolution of two-photon states in an elliptic array of waveguides. We characterise the photonic chip via coherent-light tomography and use the results to predict distinct differences between temporally indistinguishable and distinguishable two-photon inputs which we then compare with experimental observations. Our work highlights the feasibility for emulation of coherent quantum phenomena in three-dimensional waveguide structures.Comment: 8 pages, 7 figure