Developing performance-portable molecular dynamics kernels in Open CL

This paper investigates the development of a molecular dynamics code that is highly portable between architectures. Using OpenCL, we develop an implementation of Sandia’s miniMD benchmark that achieves good levels of performance across a wide range of hardware: CPUs, discrete GPUs and integrated GPUs. We demonstrate that the performance bottlenecks of miniMD’s short-range force calculation kernel are the same across these architectures, and detail a number of platform- agnostic optimisations that improve its performance by at least 2x on all hardware considered. Our complete code is shown to be 1.7x faster than the original miniMD, and at most 2x slower than implementations individually hand-tuned for a specific architecture

Global Noise and Global Englishes

Global Noise: Rap and Hip-Hop Outside the USA, alluding to Tricia Rose’s US rap-music book, Black Noise, aims to do much more than merely extend the reach of the study of rap and hip-hop beyond the USA, as its subtitle might suggest. While acknowledging the importance of the work of both Rose and Potter, this collection’s editor, Tony Mitchell, contests their respective views that rap and hip-hop are essentially expressions of African-American culture, and that all forms of rap and hip-hop derive from these origins. He argues that these forms have become ‘a vehicle for global youth affiliations and a tool for reworking local iden- tity all over the world’

Principled polycentrism and resourceful speakers

©2014 Asian Association of Teachers of English as a Foreign Language.All rights reserved. A central goal of language education is the development of resourceful speakers, people who have both good access to a range of linguistic resources and are good at shifting between styles, discourses, registers and genres. Communication becomes possible not because we adhere to global or even regional norms, but because language users are able to bring their communication into alignment with each other. Drawing on a series of studies of both online and face-to-face interaction in different cities in Asia, this paper suggests that to understand communication in contexts of diversity, we need to focus less on a supposed shared code and more on the interactions among language resources, activities and space. This in turn suggests that in order to pursue intelligibility in multilingual contexts we need a model of principled polycentrism, not the polycentrism of a World Englishes focus, with its established norms of regional varieties of English, nor the reduced communicative domain of the English as a lingua franca framework, but a more fluid yet principled approach to the diversity of contemporary contexts of communication

The Carnegie Position on Enterprise

The Carnegie UK Trust has a 100 year history of empowering young people and supporting access to high-quality education and projects which help young people to develop their skills and improve their employability. The Trust's position paper on enterprise demonstrates how access to high-quality enterprise education and entrepreneurial learning has the potential to improve students' knowledge, skills and attitudes towards self-employment which can create economic activity and jobs, and highlights examples of good practice from across the UK and Ireland

The Formation and Stability of a Microbial Community

New communities form regularly in nature, as many species rush to colonise a freshly formed island, pool, or microbiome, but it is unclear what rules govern the arrangement of these founders into a smaller, stable community, or whether the process is predictable. I simultaneously inoculated a master mix of bacterial colonisers into 45 identical environments, and allowed them to compete and evolve for around three months. By the end of the experiment, the species compositions of these communities had split into two broad groups, defined mostly by the mutual exclusivity of two Pseudomonas species, which may represent the ecological equivalence of the two species. Due to this functional similarity, I propose that community formation may be predictable at an ecological level, if not a taxonomic level. I also explored one of the communities formed in this experiment in further detail, investigating the maintenance of its diversity and stability. The community was fairly stable, as every species was able to persist even when it began at a much lower population size than its competitors, and no diversity was lost after 4 weeks of culture. I grew the species from this community in monoculture, as well as in every possible pair, triplet, and quartet, to fully assess the network of interactions, and found evidence for many significant higher-order interactions, which have been shown to have a stabilising effect in theoretical models

Column ratio mapping: a processing technique for atomic resolution high angle annular dark field(HAADF) images

An image processing technique is presented for atomic resolution high-angle annular dark-field (HAADF) images that have been acquired using scanning transmission electron microscopy (STEM). This technique is termed column ratio mapping and involves the automated process of measuring atomic column intensity ratios in high-resolution HAADF images. This technique was developed to provide a fuller analysis of HAADF images than the usual method of drawing single intensity line profiles across a few areas of interest. For instance, column ratio mapping reveals the compositional distribution across the whole HAADF image and allows a statistical analysis and an estimation of errors. This has proven to be a very valuable technique as it can provide a more detailed assessment of the sharpness of interfacial structures from HAADF images. The technique of column ratio mapping is described in terms of a [1 1 0]-oriented zinc-blende structured AlAs/GaAs superlattice using the 1 Å-scale resolution capability of the aberration-corrected SuperSTEM 1 instrument

Reforming Ontario Teachers (1990-2010): The Role of the College of Teachers

This dissertation takes up the idea of the teacher as a professional and examines the period in Ontario between 1990 and 2010 when a change in teacher governance through the creation of the College of Teachers contributed to a refocusing of teacher evaluation policy and a redefining of what it means to be a professional teacher. Across a wide variety of settings, teachers are now viewed as central to successful education reform with the result that the requisite qualities of the professional teacher and how teachers are to be transformed to achieve these qualities have become the subjects of intense policy debate. The research uses Foucault’s conceptualizations of discourse, subjectivity, power, governmentality, and panopticism as a lens to analyze the data. Because of their importance for hiring, firing, and promotion purposes, teacher evaluation documents were chosen as representative examples of teacher professionalism, and the changes in these documents were traced over time between 1990 and 2010. In addition, this qualitative study draws on data from 25 semi-structured interviews with principals and teachers who were employed in Ontario public schools throughout this time period. These principals implemented the teacher evaluations, and the teachers experienced the evaluation process. Of interest was the meaning and influence these educators assigned to the practice of teacher evaluation. Despite the principals’ belief that they could offer useful advice about teaching, the research discovered that the evaluation process had little effect on teachers’ classroom practices. However, what did profoundly affect teachers’ practices with students was the disciplinary role assumed by the newly established College of Teachers and fears of being falsely accused of sexual misconduct. Although there is no category in the teacher evaluation forms that records the successful demonstration of safe practices such as never being alone with a student without supervision and using only appropriate touch with students, the safe teacher has become a new professional ideal. This sense of the teacher-as-potential-pedophile is a global phenomenon that marks the deep loss of trust in the teaching profession in Western neoliberal nations