Unruh Radiation, Holography and Boundary Cosmology

A uniformly acclerated observer in anti-deSitter space-time is known to detect thermal radiation when the acceleration exceeds a critical value. We investigate the holographic interpretation of this phenomenon. For uniformly accelerated trajectories transverse to the boundary of the AdS space, the hologram is a blob which expands along the boundary. Observers on the boundary co-moving with the hologram become observers in cosmological space-times. For supercritical accelerations one gets a Milne universe when the holographic screen is the boundary in Poincare coordinates, while for the boundary in hyperspherical coordinates one gets deSitter spacetimes. The presence or absence of thermality is then interpreted in terms of specific classes of observers in these cosmologies.Comment: LaTeX, 35 pages, 3 figures. A reference is added and typos are correcte

Using Large-Scale Assessment Datasets for Research in Science and Mathematics Education: Programme for International Student Assessment (PISA)

Large-scale assessments of student achievement provide a window into the broadly defined concepts of literacy and generate information about levels and types of student achievement in relation to some of the correlates of learning, such as student background, attitudes, and perceptions, and perhaps school and home characteristics. This paper provides an overview and outlines potential research opportunities of one such assessment—the Programme for International Student Assessment (PISA). In order to provide examples of the work that can be accomplished with these data, we describe and discuss the results generated from PISA 2000 and PISA 2003 in terms of international comparisons of achievement and the models of relational patterns of student, home, and school characteristics. We provide insight from the recent pilot testing conducted in Taiwan for PISA 2006, which has a focus on scientific literacy. This is followed by a discussion of the implications and potentials of the 2000 and 2003 datasets to facilitate research on scientific and mathematical literacy. The paper concludes with a look ahead to PISA 2006 and what researchers should be attending to in the research reports generated from the OECD and the research interests that they could follow given access to the datasets generated