Static and dynamic accuracy of a magnetic-inertial measurement unit used to provide racket swing kinematics

Magnetic-inertial measurement units (MIMUs) are becoming more prevalent in sports biomechanics and may be a viable tool to evaluate kinematic parameters. This study examined the accuracy of a MIMU to estimate orientation angles under static conditions and dynamically from a squash racket during a forehand drive shot. A MIMU was mounted onto a goniometer and moved through 0–90°, with static data collected at 10° increments during 10 repetitions of all three axes. Typical error analyses showed the MIMU to be very reliable (TE ≤ 0.03°). MIMU accuracy was determined via intraclass correlation coefficients (ICC) (r > 0.999, p < 0.001). An ordinary least products regression showed no proportional bias and minimal fixed bias for all axes. Dynamic accuracy was assessed by comparing MIMU and optical motion capture data of squash racket swing kinematics. A MIMU was fixed onto a racket and 10 participants each hit 10 forehand shots. Mean orientation angle error at ball impact was <0.50° and ICC showed very high correlations (r ≥ 0.988, p < 0.001) for all orientations. Swing phase root mean squared errors were ≤2.20°. These results indicate that a MIMU could be used to accurately and reliably estimate selected racket swing kinematics.     

JournalGuide: bringing authors and journals together

• As a result of the considerable (and growing) number of scholarly journals, it is difficult for authors to find the best place for their research, even as many journals face challenges in finding new submissions.
• JournalGuide ( www.journalguide.com ) is a free tool that matches user‐inputted keywords or text to article metadata and returns journals that have recently published similar work.
• Users can then compare information about these journals and make an informed decision about where to submit.

     

Empowerment or impediment? School governance in the school-based management era in Hong Kong

Following the international trend in education towards democracy and decentralization, the Hong Kong government introduced a school-based management (SBM) system about two decades ago. It is widely recognized in the literature that decentralization, empowering school level management and marginalizing the influence of the intermediate level of governance, can result in better deployment of school resources and better meet the demands of various stakeholders. However, in the unique historical and cultural context of Hong Kong, the advantages of decentralization claimed in the literature have yet to be fully realized. This paper discusses the contextual factors affecting the implementation of SBM in Hong Kong, and examines their impact on four major stakeholders, namely the government, the principals, the teachers, and the parents in the wake of reform.     

Libraries and Spatial Literacy: Toward Next-Generation Education

The role of the library is to assist citizens in skills development critical to national interest and empowerment as literacy ambassadors, in general. Specifically, the work by the Federal Geographic Data Committee (1994) indicates that spatial literacy is for every citizen and not just a set of workforce specialists. Hence, the use of maps in decision making and problem solving will become fundamental to all professions, including library professionals. Thus, a spatial literacy awareness and rationale for such as standard job ability is discussed as a future librarian workforce proficiency and knowledge transfer medium.     

The negative effect of school-average ability on science self-concept in the UK,the UK countries and the world: the Big-Fish-Little-Pond-Effect for PISA 2006

Research on the relation between students’ achievement (ACH) and their academic self-concept (ASC) has consistently shown a Big-Fish-Little-Pond-Effect (BFLPE); ASC is positively affected by individual ACH, but negatively affected by school-average ACH. Surprisingly, however, there are few good UK studies of the BFLPE and few anywhere in the world based on science self-concept (S-ASC). Addressing this substantive limitation in existing research with data from PISA 2006, we extend new multigroup doubly-latent multilevel structural equation models – a substantive-methodological synergy. BFLPE predictions for S-ASC are supported for: the total international sample; the total UK sample; each of the four UK countries considered separately. The BFLPE was marginally larger in the UK than the international sample. However, consistent with the selective nature of school systems in the UK, the BFLPE was larger in Northern Ireland and, to a lesser extent, England than in Scotland or Wales.     

Random Permutation Testing Applied to Measurement Invariance Testing with Ordered-Categorical Indicators

We describe and evaluate a random permutation test of measurement invariance with ordered-categorical data. To calculate a p-value for the observed (?)χ², an empirical reference distribution is built by repeatedly shuffling the grouping variable, then saving the χ² from a configural model, or the ?χ² between configural and scalar-invariance models, fitted to each permuted dataset. The current gold standard in this context is a robust mean- and variance-adjusted ?χ² test proposed by Satorra (2000), which yields inflated Type I errors, particularly when thresholds are asymmetric, unless samples sizes are quite large (Bandalos, 2014; Sass et al., 2014). In a Monte Carlo simulation, we compare permutation to three implementations of Satorra’s robust χ² across a variety of conditions evaluating configural and scalar invariance. Results suggest permutation can better control Type I error rates while providing comparable power under conditions that the standard robust test yields inflated errors.     

Instructional leadership practices in Singapore

This paper presents a review of the literature on principal instructional leadership in Singapore. The authors investigated the dimensions of instructional leadership in the practices of Singapore principals and highlighted the strategies these leaders adopt to enact their instructional roles. Singapore principals were found to play an active role in defining the school vision and promoting the school climate. However, in the areas of curriculum implementation and classroom instruction, the middle management team in the school played more active roles as compared to principals. Five broad conclusions were discussed to provide perspectives on instructional leadership practices in Singapore. This paper also highlighted limitations on current instructional leadership research in Singapore and pointed to areas of future research.     

College Costs and Credit Cards: How Student Credit Card Use Influences College Degree Attainment

Research in Higher Education - Since the turn of the twenty-first century, going to college has become increasingly financially difficult in the United States. Tuition prices continued to rise,...