The validation of a swimming turn wall-contact-time measurement system: a touchpad application reliability study

The effectiveness of the swimming turn is highly influential to overall performance in competitive swimming. The push-off or wall contact, within the turn phase, is directly involved in determining the speed the swimmer leaves the wall. Therefore, it is paramount to develop reliable methods to measure the wall-contact-time during the turn phase for training and research purposes. The aim of this study was to determine the concurrent validity and reliability of the Pool Pad App to measure wall-contact-time during the freestyle and backstroke tumble turn. The wall-contact-times of nine elite and sub-elite participants were recorded during their regular training sessions. Concurrent validity statistics included the standardised typical error estimate, linear analysis and effect sizes while the intraclass correlating coefficient (ICC) was used for the reliability statistics. The standardised typical error estimate resulted in a moderate Cohen’s d effect size with an R² value of 0.80 and the ICC between the Pool Pad and 2D video footage was 0.89. Despite these measurement differences, the results from this concurrent validity and reliability analyses demonstrated that the Pool Pad is suitable for measuring wall-contact-time during the freestyle and backstroke tumble turn within a training environment.     

中国煤炭需求弹性估算:时间波动与区际差异

需求弹性是经济学中的基础概念,也是我国煤炭市场化进程中的重要研究对象.不同于以往的宽泛研究,本文分别从国家维度、时间维度和区域维度对1995-2010年间的我国煤炭需求弹性展开系统化研究.基于面板数据模型的研究发现全国煤炭需求的价格弹性为0.59,煤炭在所考察期间总体呈现出刚性需求现象,但基于截面数据的回归结果显示各考察年份的煤炭需求弹性为负值且存在着较大的时间波动,而各区域时间序列的回归结果表明煤炭需求弹性的区际差异: 煤炭主产地其值为负,消费地其值为正.分析发现以国家维度和时间维度的研究结论相互矛盾,而以区域维度的研究结果更加科学合理,具有更为可靠的理论和现实指导意义.     

The Addition Property of Expectation – An Example to Convince

This article describes an example that is designed to convince students of the addition property of expectation.     

First-Year Non-STEM Majors’ Use of Definitions to Solve Calculus Tasks: Benefits of Using Concept Image over Concept Definition?

Six US first-year university students in humanities or social science degree programmes were interviewed while solving 4 tasks on continuity and asymptotes in a required mathematics course. The focus was on how the students referred to the definitions or to the concept images when solving the tasks and if partial understandings appeared. Partial understanding denotes when the definition or the concept image has correct parts but essential parts are missing or incoherencies occur. Some students confused continuity with differentiability or perceived it as a graph not having holes, which is also reported by other studies. Another misconception that emerged is to perceive points on the x-axis as non-continuous. The partial understandings of asymptotes were related to the vertical asymptote as it was confused with a function property. Some students referred to the definitions when correctly solving some of the tasks and some students with coherent concept images were successful solving some of the tasks even when they did not refer to the definitions.     

Governmental innovation support in Norway: Micro- and macro-level effects

The present article focuses on a government supported program in Norway. “The Innovation Plan”, aiming at overcoming the critical lack of innovation now facing industry. A framework based on the well known structure-conduct-performance paradigm serves as the theoretical point of departure. Both secondary and primary data are applied to assess micro- and macro-level effects.In this piece of research governmental R&D support was found to exert an impact on the level of R&D activities, as well as on the willingness to direct R&D resources towards projects representing solutions high in novelty. Various types of positive outcomes such as increased technical competence and spin-offs, as well as various types of economic effects could also be traced for the supported projects. Implications of the findings are highlighted.     

Can international elite sport success trickle down to mass sport participation? Evidence from Danish team handball

Many scholars do not find evidence of a trickle-down effect from elite sport success to mass sport participation. Contrary to what is assumed by the trickle-down effect “theorem”, successful elite sportspeople do not seem to inspire amateurs to take up sport themselves. However, recent studies present evidence that elite sport can have an influence. In this article, we apply regression models on time series data from one of the most successful Danish sports, team handball. Our findings are mixed, but lean towards supporting scholars who argue that trickle-down effects are not necessarily an inherent part of international sporting success. Further studies should examine more sports to identify where trickle-down effects occur and why.