3D hydrodynamic simulations of carbon burning in massive stars

We present the first detailed 3D hydrodynamic implicit large eddy simulations of turbulent convection of carbon burning in massive stars. Simulations begin with radial profiles mapped from a carbon-burning shell within a 15 M⊙ 1D stellar evolution model. We consider models with 1283, 2563, 5123, and 10243 zones. The turbulent flow properties of these carbon-burning simulations are very similar to the oxygen-burning case. We performed a mean field analysis of the kinetic energy budgets within the Reynolds-averaged Navier–Stokes framework. For the upper convective boundary region, we find that the numerical dissipation is insensitive to resolution for linear mesh resolutions above 512 grid points. For the stiffer, more stratified lower boundary, our highest resolution model still shows signs of decreasing sub-grid dissipation suggesting it is not yet numerically converged. We find that the widths of the upper and lower boundaries are roughly 30 per cent and 10 per cent of the local pressure scaleheights, respectively. The shape of the boundaries is significantly different from those used in stellar evolution models. As in past oxygen-shell-burning simulations, we observe entrainment at both boundaries in our carbon-shell-burning simulations. In the large Péclet number regime found in the advanced phases, the entrainment rate is roughly inversely proportional to the bulk Richardson number, RiB (∝RiB−α, 0.5 ≲ α ≲ 1.0). We thus suggest the use of RiB as a means to take into account the results of 3D hydrodynamics simulations in new 1D prescriptions of convective boundary mixing

Developing a Pedagogical Framework for Designing a Multisensory Serious Gaming Environment

The importance of multisensory interaction for learning has increased with improved understanding of children’s sensory development, and a flourishing interest in embodied cognition. The potential to foster new forms of multisensory interaction through various sensor, mobile and haptic technologies is promising in providing new ways for young children to engage with key mathematical concepts. However, designing effective learning environments for real world classrooms is challenging, and requires a pedagogically, rather than technologically, driven approach to design. This paper describes initial work underpinning the development of a pedagogical framework, intended to inform the design of a multisensory serious gaming environment. It identifies the theoretical basis of the framework, illustrates how this informs teaching strategies, and outlines key technology research driven perspectives and considerations important for informing design. An initial table mapping mathematical concepts to design, a framework of considerations for design, and a process model of how the framework will continue to be developed across the design process are provided

Dependence of convective boundary mixing on boundary properties and turbulence strength

Convective boundary mixing is one of the major uncertainties in stellar evolution. In order to study its dependence on boundary properties and turbulence strength in a controlled way, we computed a series of 3D hydrodynamical simulations of stellar convection during carbon burning with a varying boosting factor of the driving luminosity. Our 3D implicit large eddy simulations were computed with the prompi code. We performed a mean field analysis of the simulations within the Reynolds-averaged Navier–Stokes framework. Both the vertical rms velocity within the convective region and the bulk Richardson number of the boundaries are found to scale with the driving luminosity as expected from theory: $v$ ∝ L1/3 and RiB ∝ L−2/3, respectively. The positions of the convective boundaries were estimated through the composition profiles across them, and the strength of convective boundary mixing was determined by analysing the boundaries within the framework of the entrainment law. We find that the entrainment is approximately inversely proportional to the bulk Richardson number, RiB (\propto \textrmRi_\textrmB^-α , α \sim 0.75). Although the entrainment law does not encompass all the processes occurring at boundaries, our results support the use of the entrainment law to describe convective boundary mixing in 1D models, at least for the advanced phases. The next steps and challenges ahead are also discussed

From witness to web sleuth: Does citizen enquiry using social media affect formal eyewitness identification procedures?

Eyewitnesses to crimes may seek the perpetrator on social media prior to participating in a formal identification procedure, but the effect of this citizen enquiry on the accuracy of eyewitness identification is unclear. The current study used a between-participants design to address this question. Participants viewed a crime video, and after a 1-2 day delay were either exposed to social media including the perpetrator, exposed to social media that substituted an innocent suspect for the perpetrator, or not exposed to social media. Seven days after viewing the crime video, all participants made an identification from a video lineup. It was predicted that exposure to social media that did not contain the guilty suspect would reduce the accuracy of subsequent identifications. Analysis revealed no association between social media exposure and lineup response for target present lineups. For target absent lineups there was a significant association between social media exposure and lineup response, but this was driven by a higher number of correct rejections for participants who saw the guilty suspect on social media. The results suggest that, at least in some circumstances, witnesses searching social media does not have a negative effect on formal ID procedures

Reciprocal elucidation: a student-led pedagogy in multidisciplinary undergraduate research conferences

© 2016 HERDSA. There is no previous study of the benefits of attending a national multidisciplinary conference dedicated to undergraduate researchers, despite the growing number of such conferences internationally. This paper addresses the gap in knowledge of the learning gains from these conferences, and reveals a student driven learning process, a multidisciplinary signature pedagogy. It presents the results of 90 in-depth interviews with student conference participants conducted over three consecutive years of a multidisciplinary National Conference of Undergraduate Research (2012–2014). This paper uniquely captures the student voice on their perceived learning gains from this experience. The results reveal that some students co-create a pedagogy of Foucauldian reciprocal elucidation, through a sense of ‘unfinishedness’, allowing them to reflect on their own learning in the light of divergent perspectives, questions and frames of reference. Bidirectional exchange of ideas and insights enabled students to ask and answer questions that transformed each other’s thinking, allowing them to arrive at understandings they could not have achieved by themselves. The opportunity to present research in an authentic setting beyond disciplinary and institutional contexts developed students’ skills and confidence, giving additional value over and above the recognised benefits of engaging in research. The undergraduate research conference is framed as a threshold experience for the development of self-authorship. Significant implications for practice include supporting constructive dialogues between students and the creation of authentic and professional multidisciplinary contexts for sharing research

Hybrid content-specific and generic approaches to lesson observation: Possibilities and practicalities

This paper considers various approaches to classroom observation that combine generic and mathematics content-specific dimensions of instructional quality. Using results from previous research in which three research teams each analysed the same three mathematics lessons (from fourth-grade mathematics classrooms in the USA) using different frameworks, we compare features of the frameworks and assess the extent to which these lead to convergent, divergent or complementary assessments of instructional quality. These findings inform reflections on how a synthesis of existing conceptualisations of instructional quality captures shared aspects of different frameworks but may be differentially useful than individual frameworks depending upon the purposes of observations. Specifically, single frameworks may be particularly useful within specific contexts and for professional development and accountability, but a synthesis of frameworks can foster more coherent cross-cultural understandings of instructional quality. We argue that establishing international networks of scholars can facilitate collaborations aiming to investigate and understand instructional quality