D1 and D5-brane giant gravitons on AdS3×S3×S3×S1AdS_3 \times S^3 \times S^3 \times S^1

We construct various examples of 1/4-BPS giant gravitons embedded into the type IIB supergravity background $AdS_{3} \times S^{3}_{+} \times S^{3}_{-} \times S^{1}$ with pure R-R flux: two D1-brane giants wrapping 1-cycles in $AdS_{3}$ and $S^{3}_{+} \times S^{3}_{-}$, and one D5-brane giant wrapping a 4-cycle in $S^{3}_{+} \times S^{3}_{-}$ and the $S^{1}$. These D-branes are supported by angular momenta $\alpha$ P on one 3-sphere and $(1-\alpha)$ P on the other. We then construct a general class of 1/8-BPS D5-brane giant gravitons wrapping 4-cycles $\Sigma$ in $S^{3}_{+} \times S^{3}_{-}$ and the $S^{1}$. Here $\Sigma$ is the intersection of a holomorphic surface $\mathcal{C}$ in $\mathbb{C}^{2}_{+} \times \mathbb{C}^{2}_{-}$ with the $S^{3}_{+} \times S^{3}_{-}$ submanifold. The holomorphic surface $\mathcal{C}$ is defined by $f(y_{1}z_{1},y_{1}z_{2},y_{2}z_{1},y_{2}z_{2}) = 0$, with $y_{a}$ and $z_{a}$ the $\mathbb{C}^{2}_{\pm}$ complex coordinates. There is supersymmetry enhancement to 1/4-BPS in the special case $f(y_{1}z_{1}) = 0$ of which our original D5-brane giant graviton is an example.Comment: 30 pages, 4 figures. reference and figure added, minor change

Building the Learning Analytics Curriculum: Should we Teach (a Code of) Ethics?

This brief chapter explores the feasibility of teaching (a code of) ethics against a background which examines our views around data scientists, data analysis, data and, in particular, student data. It touches upon different approaches to ethics and asks whether teaching ethics would make any difference

Student perspectives on the use of their data: between intrusion, surveillance and care

The Open University (OU) is a large, open distance learning institution with more than 200,000 students. In common with many other higher education institutions (HEIs), the University is looking more closely at its use of learning analytics. Learning analytics has been defined as the collection and analysis of data generated during the learning process in order to improve the quality of learning and teaching (Siemens, Dawson, & Lynch, 2013). In the context of the Open University, learning analytics is the use of raw and analysed student data to, inter alia, proactively identify interventions which aim to support students in completing their study goals. Such interventions may be designed to support students as individuals as well as at a cohort level. The use of a learning analytics approach to inform and provide direction to student support within the Open University is relatively new and, as such, existing policies relating and referring to potential uses of student data have required fresh scrutiny to ensure their continued relevance and completeness (Prinsloo & Slade, 2013). In response, The Open University made the decision to address a range of ethical issues relating to the University’s approach to learning analytics via the implementation of new policy. In order to formulate a clear policy which reflected the University’s mission and key principles, it was considered essential to consult with a wide range of stakeholders, including students

Stemming the flow: improving retention for distance learning students

Though concern about student attrition and failure is not a new phenomenon, higher education institutions (HEIs) have struggled to significantly reduce the revolving door syndrome. Open distance learning higher education is particularly susceptible to high student attrition. Despite a great deal of research into the student journey and factors impacting on likely success, we are not necessarily closer to understanding and being able to mitigate against student attrition. Learning analytics as emerging discipline and practice promises to help penetrate the fog… This case study describes work undertaken at the Open University in the UK to investigate how a learning analytics approach allows the University to provide timely and appropriate student support in a cost-effective manner. It includes a summary of the establishment of curriculum-based student support teams and a framework which defines more standardised student support informed by both student data and an enhanced knowledge of the curriculum. The primary aim of student support teams is to proactively support students through their study journey and to optimise their chances of reaching their declared study goals. Higher education institutions (HEIs) are making increasing use of learning analytics to support delivery of timely and relevant student support. The Open University in the UK, like other HEIs, knows a great deal about its students before they start to study and is able to track student behaviours once study has begun. Until recently, the university has not taken full advantage of the additional insight offered by such information. This paper describes the framework of support interventions established for all student support teams and describes the learning analytics approach used to support that framework

Integrable open spin-chains in AdS3/CFT2 correspondences

We study integrable open boundary conditions for d(2,1;\alpha)^2 and psu(1,1|2)^2 spin-chains. Magnon excitations of these open spin-chains are mapped to massive excitations of type IIB open superstrings ending on D-branes in the AdS_3 x S^3 x S^3 x S^1 and AdS_3 x S^3 x T^4 supergravity geometries with pure R-R flux. We derive reflection matrix solutions of the boundary Yang-Baxter equation which intertwine representations of a variety of boundary coideal subalgebras of the bulk Hopf superalgebra. Many of these integrable boundaries are matched to D1- and D5-brane maximal giant gravitons.Comment: v1: 61 pages, 6 figures; v2: minor changes and reference added; v3: minor changes, 60 pages, version accepted to journa

In the eye of the storm: preliminary evidence on the use of online learning diaries

The surprising lack of pressure and speed in the centre of the vortex of a storm are in stark contrast to the force and destruction often experienced at its periphery. Many spectators watching a developing storm will be caught between fear and a desire to escape. The metaphor of a storm has been applied here to the emotions experienced by many students enrolling in online learning courses. Not only do the requirements of studying online collide with personal and professional commitments, the experience of learning online (often in groups) results in many students feeling displaced, scared or out of control. Learning diaries, especially in an online environment, present students with an opportunity to reach the centre of the vortex, though this may not be as quiet and safe as we may have presumed. This paper reports on students’ reflections in their learning diaries as a prescriptive part of the Professional Certificate in Management offered by the Open University. The research focused on the unstructured learning diary entries of 12 students from one tutor group over an 18 day period of a short compulsory online course. This phenomenographic study used grounded theory as methodology to analyse and describe students’ use of their learning diaries. The research found ample evidence that online learning diaries provide students with a safe space to reflect on the vortex around them. Without a quiet and reflective centre, students may be overwhelmed by the wider forces impacting on them. Students’ postings provided rich descriptions of the vortex of studying online and the function of having a centre to which to withdraw. There is, however, also evidence that posting reflections in learning diaries can itself be a dislocating and uncomfortable experience for some learners, while others question its usefulness. The work provides practical and useful information for managers of online learning experiences, instructional designers and curriculum developer

A giant graviton genealogy

In this article we extend the construction of giant gravitons from holomorphic surfaces [arXiv:hep-th/0010206] to the ABJM correspondence. We construct a new class of 1/6-BPS M5-branes wrapping 5-manifolds in S^7/Z_k and supported by a large angular momentum in the orbifold space. These orbifold giant gravitons undergo a supersymmetry enhancement to 1/3-BPS and 1/2-BPS configurations in special cases. The compactification of M-theory on AdS_4 x S^7/Z_k to type IIA superstring theory on AdS_4 x CP^3 then gives rise to another new class of 1/6-BPS D4 and NS5-branes wrapping 4 and 5-manifolds in CP^3. The D4-branes carry a combination of D0-brane charge and angular momentum in the complex projective space, while the NS5-branes are supported only by D0-brane charge. Finally, we present a detailed analysis of a one-parameter family of 1/2-BPS M5-brane orbifold giant gravitons, and their D4 and NS5-brane CP^3 descendants.Comment: 34 pages; 1 figure; minor revisions; references adde