A material-dialogic perspective on powerful knowledge and matter within a science classroom

“Powerful” disciplinary knowledge has the potential to enrich students’ lives by providing access to understanding beyond everyday experience (Young 2011). Learning science or any other school subject requires understanding of the core body of content within an academic discipline. However, contemporary discussion of disciplinary knowledge remains at the sociological level, offering little clarity around how such knowledge manifests in the complex and unique contexts in which people learn. The framing of powerful knowledge inherits a dualist philosophical assumption that a curriculum concept is a universal phenomenon, acquired through a myriad of activities and applied in new situations, but nevertheless something which is acquired (or not) (Hardman, 2019). The question then becomes how these universal concepts are acquired through the unique context of a specific classroom. Gericke et al. (2018) begin to address this question by highlighting the transformations made as disciplinary knowledge is taught in schools. These transformations occur at the societal, institutional and classroom levels. The term ‘transformation’ is an umbrella term reflected in both the tradition of didactics, for example, ‘didactic transposition’ (Chevallard 2007), ‘omstilling’ (Ongstad 2006) and ‘reconstruction’ (Duit 2013), as well as within the curriculum tradition in Bernstein’s (1973) notion of ‘re-contextualization’. As well as considering transformations, the term epistemic quality moves us towards conceptualizing how classroom activities have differing qualities in conveying the epistemology of disciplines (Hudson, 2018). In this chapter, we focus on the classroom, and seek to address the overarching question of: How can the transformation processes related to powerful knowledge and epistemic quality be described? Our contention is that the notions of transformation and epistemic quality hold the potential to frame the ways in which disciplinary knowledge and epistemology manifest in the classroom. However, as these notions are being developed, in this book and elsewhere, we wish to guard against any simplistic framing whereby idealised disciplinary understandings are in some way represented in classrooms. In our view, a learner does not receive a reduced, simplified form of some universal understanding. Understanding of a subject discipline, in terms of both knowledge and the epistemology of the discipline, emerge from the dynamic, messy and material contexts of classrooms. In this chapter, we consider how a material-dialogic frame (Hetherington et al. 2018; Hetherington and Wegerif, 2018) might contribute to this discussion. We first briefly lay out the material-dialogic frame and our reasons for proposing it. After that, we use a case study of a science classroom to support the usefulness of the frame in considering transformations of disciplinary knowledge in classrooms

The effectiveness of a social media intervention for reducing portion sizes in young adults and adolescents

open access journalAbstract Objective: Adolescents and young adults select larger portions of energy-dense food than recommended. The majority of young people have a social media profile, and peer influence on social media may moderate the size of portions selected. Methods: Two pilot-interventions examined whether exposure to images of peers’ portions of high-energy-dense (HED) snacks and sugar-sweetened-beverages (SSBs) on social media (Instagram) would influence reported desired portions selected on a survey. Confederate peers posted ‘their’ portions of HED snacks and SSBs on Instagram. At baseline and intervention end participants completed surveys that assessed desired portion sizes. Results: In intervention 1, Undergraduate students (N=20, Mean age=19.0y, SD=0.65y) participated in a two-week intervention in a within-subjects design. Participants reported smaller desired portions of HED snacks and SSBs following the intervention, and smaller desired portions of HED snacks for their peers. In intervention 2, adolescents (N=44, Mean age=14.4y, SD=1.06y) participated in a four-week intervention (n=23) or control condition (n=21) in a between-subjects design. Intervention 2 did not influence adolescents to reduce their desired reported portion sizes of HED snacks or SSBs relative to control. Conclusions: These preliminary studies demonstrated that social media is a feasible way to communicate with young people. However, while the intervention influenced young adults’ reported desired portions and social norms regarding their peers’ portions, no significant impact on desired reported portion sizes was found for HED snacks and SSBs in adolescents. Desired portion sizes of some foods and beverages may be resistant to change via a social media intervention in this age group

A Caching Scheme to Accelerate Kinetic Monte Carlo Simulations of Catalytic Reactions

Kinetic Monte Carlo (KMC) simulations have been instrumental in advancing our fundamental understanding of heterogeneously catalyzed reactions, with particular emphasis on structure sensitivity, ensemble effects, and the interplay between adlayer structure and adsorbate-adsorbate lateral interactions in shaping the observed kinetics. Yet, the computational cost of KMC remains high, thereby motivating the development of acceleration schemes that would improve the simulation effciency. We present an exact such scheme, which implements a caching algorithm along with shared-memory parallelization to improve the computational performance of simulations incorporating long-range adsorbate-adsorbate lateral interactions. This scheme is based on caching information about the energetic interaction patterns associated with the products of each possible lattice process (adsorption, desorption, reaction etc). Thus, every time a reaction occurs ("ongoing reaction") it enables fast updates of the rate constants of "affected reactions", i.e. possible reactions in the region of influence of the "ongoing reaction". Benchmarks on KMC simulations of NOx oxidation/reduction, yield acceleration factors of up to 20× when comparing single-thread runs without caching to runs on 16 threads with caching, for simulations with a cluster expansion Hamiltonian that incorporates up to 8th nearest-neighbor interactions

CMakeCatchTemplate: A C++ template project

CMakeCatchTemplate (https://github.com/MattClarkson/CMakeCatchTemplate) is a project to provide a starting structure for C++ projects configured with CMake, that can be customised to work in a variety of scenarios, allowing developers to deploy new algorithms to users in a shorter timeframe. Main features include a SuperBuild to build optional dependencies; unit tests using Catch; support for CUDA, OpenMP and MPI; examples of command line and GUI applications; Doxygen integration; Continuous Integration templates and support for building/deploying Python modules

Characterization of the glass transition in vitreous silica by temperature scanning small-angle X-ray scattering

The temperature dependence of the x-ray scattering in the region below the first sharp diffraction peak was measured for silica glasses with low and high OH content (GE-124 and Corning 7980). Data were obtained upon scanning the temperature at 10, 40 and 80 K/min between 400 K and 1820 K. The measurements resolve, for the first time, the hysteresis between heating and cooling through the glass transition for silica glass, and the data have a better signal to noise ratio than previous light scattering and differential thermal analysis data. For the glass with the higher hydroxyl concentration the glass transition is broader and at a lower temperature. Fits of the data to the Adam-Gibbs-Fulcher equation provide updated kinetic parameters for this very strong glass. The temperature derivative of the observed X-ray scattering matches that of light scattering to within 14%.Comment: EurophysicsLetters, in pres

Surveyor batteries Final engineering report

Design and performance of Surveyor spacecraft silver-zinc main batter