Gradient coil and radiofrequency induced heating of orthopaedic implants in MRI: influencing factors

Patients with implanted orthopaedic devices represent a growing number of subjects undergoing magnetic resonance imaging (MRI) scans each year. MRI safety labelling is required for all implants under the EU Medical Device Regulations to ensure regulatory compliance, with each device assessed through standardised testing procedures. In this paper, we employ parametric studies to assess a range of clinically relevant factors that cause tissue heating, performing simulations with both radiofrequency (RF) and gradient coil (GC) switching fields, the latter of which is often overlooked in the literature. A series of worst case scenarios for both types of excitation field are discussed. In the case of GC fields large volume implants and large plate areas with the field oriented perpendicular to the plane cause the highest heating levels, along with sequences with high rates of field switching. Implant heating from RF fields is driven primarily from the antenna effect, with thin, linear implants of resonant length resulting in the highest temperature rises. In this work, we show that simplifications may be made to the field sequence and device geometry without significantly comprising the accuracy of the simulation results, opening up the possibility for generic estimates of the implant heating for orthopaedic device manufacturers and opportunities to simplify the safety compliance process.

P046 More teaching, less sleeping: The impact of stressful periods of the school year on the sleep of Australian schoolteachers

Introduction There are approximately 270,00 schoolteachers in Australia and this population experience multiple stressors at work. This can lead to poor sleep quality and quantity and, consequently, adverse outcomes for both schoolteachers and students. While it is well-established that certain periods of the year may lead to increased stress for schoolteachers, the impact of this on sleep is unknown. The current study aimed to investigate the effect of stressful periods of the school year on the sleep of schoolteachers. Methods The Pittsburgh Sleep Quality Inventory (PSQI) and questions on stressful school periods (including report writing, standardised testing, school appraisal, and teacher performance) were completed online by 775 Australian primary and secondary schoolteachers (89.1% female, 29.9% 25–34 years). Pearson Chi-square analyses were performed. Results Scores on the PSQI indicated that 611 (79.0%) of participants were experiencing poor sleep quality. There were significant relationships between each of the stressful periods of the year and PSQI score, such that increased stress during periods of report writing (p<0.001), standardised testing (p<0.001), school appraisal (p<0.001), and teacher performance (p<0.001) was associated with poor sleep quality. Discussion Australian schoolteachers are at risk of poor sleep quality and quantity, and this is exacerbated by stressful periods of the school year. Given the vital role schoolteachers play in the community, organisations should be mindful of these periods of the year in order to improve the sleep of schoolteachers.

Repositioning teachers as assessors:

The global trend to emphasise assessment for learning brings up the issue of repositioning teachers in assessment. The contemporary curricular policy reforms encourage teachers to take an agentic role in assessment, but multiple dimensions of the environment affect its realisation. Drawing on an ecological approach to teacher agency, this empirical study investigated how Korean secondary English teachers (KSETs) perceive and enact their own teacher agency in assessment within the ecosystem of Korean education. The dataset for the study comprises semi-structured interviews with 15 KSETs. The interview questions involved the main themes such as personal experiences over the life course regarding assessment and professional practice in assessment. The findings from the thematic analysis indicate that past environment like the excessive emphasis on high-stakes standardised testing still affected teacher perception and teacher agency in the present assessment practices directed by a curricular reform, and the incongruence the teachers experienced between past and present environment significantly influenced the enactment of teacher agency. The findings suggest teachers aspire to enact teacher agency regarding assessment through the critical interpretation of their iterative experiences, present affordances, and projective orientation. Aspirations can be compromised, however, through negotiations with the environmental conditions in assessment practice, and teachers struggle to enact teacher agency leading to ecological transformation. This study concludes with practical implications to enhance teacher agency in assessment, theoretical implications regarding the conceptual expansion of the ecological perspective and suggestions for future research.

The Impact of IMPACT: How instruction in critical thinking has a beneficial impact on standardised test performance

Critical and creative thinking are fundamental 21st century skills and ‘general capabilities’ or ‘core competencies’ of many educational systems around the world, and yet there is much confusion and indeed some doubt about whether explicit instruction in critical thinking is either necessary or desirable. Standardised testing, meanwhile, is under fire for encouraging teachers to ‘teach to the test’ in a way that, for many teachers, undermines their capacity to create opportunities for students to engage in critical and creative learning. This study, based on an examination of standardised test (NAPLAN) performance data from students enrolled in courses dedicated to the teaching of critical thinking through the Queensland Government Department of Education’s IMPACT Centre shows that explicit instruction in critical thinking is correlated with significant relative gains when those students are compared with students whose exposure to critical thinking was secondary to domain-specific knowledge. This promises (a) to provide reasons for thinking that explicit instruction in critical thinking is beneficial for students in supporting the core areas of the curriculum measured within standardised tests, and (b) to provide an antidote to the idea that the existence of standardised testing militates against inquiry-based, critical thinking pedagogical practices.

Parents and Teachers’ Perceptions of the Tone and Emotional Impact of Education News Coverage

This study examines Australian teachers (n = 268) and parents’ (n = 206) self-reported perceptions of education news coverage and how the coverage affects them. Overall, the participants reported a perception that news coverage of teachers, schools, the education system and standardised testing was generally negative in tone. Participants reported typically feeling demoralised by negative stories and inspired by positive stories. A high importance was placed upon the public perception of education by participants. However, trust in the media reporting of educational issues was low. An exception to this general pattern of findings was that participants did not place as much importance upon the public perception of standardised testing and reported being less affected by negative or positive stories on that topic compared to the other education aspects. This research is one of the few studies to investigate the potential emotional impact that news coverage of education can have on media consumers.

Accompanied versus unaccompanied walking for continuous oxygen saturation measurement during 6-min walk test in COPD: a randomised cross-over study

Study questionIs there i a difference in the 6-Min Walk Test (6 MWT) distance when the assessor accompanies the patient to continuously measure oxygen saturation (SpO2) compared to the patient walking unaccompanied?MethodsWe conducted a prospective randomised cross-over study to evaluate the impact of the assessor walking with the patient during 6 MWT (6 MWTwith) versus patient walking alone (6 MWTwithout). At the end of a pulmonary rehabilitation programme, each patient performed two 6 MWTs in random order and separated by 30 min rest.Results49 COPD patients (GOLD II-IV) were included. In a regression model adjusting for period and subject, accompanying the patient resulted in a lower walking distance (mean difference −9.1 m, [95%CI, −13.9 to −4.3], p=0.0004). Notably, six patients walked more than 30 m further (minimal important difference, MID) in one of the two conditions (6 MWTwith: n=1, 6 MWTwithout: n=5). There were no between-sequence-group differences in heart rate, dyspnoea and leg-fatigue, and SpO2. The median (interquartile range) number and duration of SpO2 signal artefacts were high but not different between the experimental conditions (6 MWTwith: 17 [4, 24], 34 s [7, 113], 6 MWTwithout: 11 [3, 26], 24 s [4, 62]).Answer to the questionOn a study population level, we observed a statistically significant difference in 6 MWT distance between the two experimental conditions, however, the magnitude of difference is small and may not be considered clinically relevant. Nevertheless, in a clinical setting, unaccompanied walking resulted in a substantially higher walking distance pointing towards strictly standardised testing methodology, in particular in pre-post study designs.

In search of the margin spaces

Virtual and Distance Learning are certainly not disruptive technologies, but rather a trend in contemporary education. However, the potential of new mobile technologies, and the openness to new pedagogies associated with them, is enabling teaching professionals to design learning instances that could truly disrupt traditional schooling (Agarwal, 2013). Societal changes such as the rise of the knowledge society and disintermediation of education (Prince, 2014) demand a learning ecosystem where learners can create their own opportunities to develop life-skills and problem solve (Hannon, Patton & Temperley, 2011). This means that learners should be given the opportunity to be their own agents of learning and build collaborative networks with both instructors and peers. However, secondary school education is still organised around students’ attainment and standardised testing, where curriculum normalisation demands supersede student-centeredness (Leadbeater, 2005). This paradigm-clash together with some limitations on teachers’ digital capabilities or/and the organizational constraints on the adoption of technology challenges the full implementation of ICT as a neural network that could enable full-personalisation and, therefore, a deep learning ecosystem. Digital technologies can no longer be considered a simple tool to access, organise and communicate information. At its lowest denomination, technology becomes a constitutive structure “which partly constitutes the things to which is applied” (Van der Hoven, 2006, p68), and acts as a medium that both impacts on the way we explore reality and mediates its understanding (Carr, 2011; Cardinali et. al; 2009; Doidge, 2007; Kurtweil, 2005, quoted by White, 2011). At its highest denomination, technology can be understood from the perspective of sociomateriality, where material means are “constitutive of both activities and identities” (Orlikowski & Scott, 2008, p 455). From the perspective of the Extended Mind Theory (Clark & Chalmers, 1998) humans and tools can work together as a functional organ, blurring the boundaries between human and technology (Hannon, 2018). Technologies are not the only medium capable of enabling deep learning, since “learning is not only the development of the fundamental competencies [but] also developing the personal, interpersonal and cognitive capabilities that allow one to diagnose what is going on in the complex, constantly shifting human and technical context of real-world practice and then match an appropriate response.” (Fullan & Scott, 2014, p4.). However, it would be naive to disregard the impact that emerging technologies are having not only on pedagogy, but also, on the economic and political pressures being transferred into secondary schools (Bolstad et al.,2012. p1). The aim of my research is to inquire into the tools that high-achieving senior secondary school learners are using to interact with digital texts in order to (a) structure their learning [organising]; (b) articulating the "external mind" [signposting] and (c) representing mental processes [synthesising] and its intersection with Biesta’s (2010) notion of the dimensions of Education from the perspective of Complexity and ANT (actor-network) theory.