On the energy functional on Finsler manifolds and applications to stationary spacetimes

In this paper we first study some global properties of the energy functional on a non-reversible Finsler manifold. In particular we present a fully detailed proof of the Palais--Smale condition under the completeness of the Finsler metric. Moreover we define a Finsler metric of Randers type, which we call Fermat metric, associated to a conformally standard stationary spacetime. We shall study the influence of the Fermat metric on the causal properties of the spacetime, mainly the global hyperbolicity. Moreover we study the relations between the energy functional of the Fermat metric and the Fermat principle for the light rays in the spacetime. This allows us to obtain existence and multiplicity results for light rays, using the Finsler theory. Finally the case of timelike geodesics with fixed energy is considered.Comment: 23 pages, AMSLaTeX. v4 matches the published versio

Lecturers' vs. students' perceptions of the accessibility of instructional materials

The goal of this study was to examine the differences between lecturers and students’ perceptions of the accessibility of instructional materials. The perceptions of 12 mature computing distance education students and 12 computing lecturers were examined using the knowledge elicitation techniques of card sorting and laddering. The study showed that lecturers had pedagogical views while students tended to concentrate on surface attributes such as appearance. Students perceived instructional materials containing visual representations as most accessible. This has two implications for the professional development of computing lecturers designing instructional materials. First, lecturers need to appreciate the differences between expert and novice views of accessibility and how students will engage with the materials. Second, lecturers need to understand that learners perceive instructional materials containing visual representations as more accessible compared to ‘text only’ versions. Hence greater use of these may enable students to engage more readily in learning. Given that print is the ubiquitous teaching medium this is likely to have implications for students and lecturers in other disciplines