Appearance of Saturn's F ring azimuthal channels for the anti-alignment configuration between the ring and Prometheus

In this article we explore the aspect of the F ring with respect to the anti-alignment configuration between the ring and Prometheus. We focus our attention on the shape of the F ring's azimuthal channels which were first reported by Porco et al. (2005) and numerically explored by Murray et al. (2005), who found excellent agreement between Cassini's ISS reprojected images and their numerical model via a direct comparison. We find that for anti-alignment the channels are wider and go deeper inside the ring material. From our numerical model we find a new feature, an island in the middle of the channel. This island is made up of the particles that have been perturbed the most by Prometheus and only appears when this satellite is close to apoapsis. In addition, plots of the anti-alignment configuration for different orbital stages of Prometheus are obtained and discussed here.Comment: Number of pages: 12, number of tables: 1, number of figures:

Dear Jacques ... Lecoq in the twenty first century

This essay considers Jacques Lecoq's influence almost 20 years after his death. Arguing that Lecoq's pedagogy is largely as relevant today as it was when he was still alive, the author speculates whether Lecoq would have welcomed developments in the use of digital technology within live performance. The essay proposes that much of Lecoq's teaching with its emphasis on play, complicite, invention, imagination and the creative actor remains relevant to contemporary developments in site-specific, immersive and postdramatic theatre. The essay is constructed in the form of a posthumous letter to Jacques Lecoq

Book review: nuclear energy: what everyone needs to know

Reviewing nuclear energy and disentangling myth from reality is essential to informing public opinion and policy making, and this accessible text provides a useful basis for assessing the risks, costs and benefits, finds Murray Collins

Writing Center as Contact Zone: Resources for Mediation

When ESL writers write, they are attempting to be heard in an academic community. One of the academy’s shortcomings is its disinclination to hear from writers who struggle with academic discourse. In a contact zone, such as a university that includes accomplished and novice academics, communication becomes a casualty (particularly with novices whose first language is not English). If writing centers and their staffs are the cultural mediators of this contact zone, then we must first be afforded the tools to do our work: a good text, skilled teachers, sufficient funding, and an un-marginalized place on the campus. Irrespective of these resources, however, writing consultants can provide ESL writers with knowledge of contrastive rhetorics and how a failure to acculturate to demands for standard American academic writing may limit their success at the university level.University Writing Cente

Existence, mixing and approximation of invariant densities for expanding maps on Rr

This paper generalises Gora and Boyarsky’s bounded variation(BV) approach to the ergodic properties of expanding transformations, and analysies the convergence of Ulam’s method for the numerical approximation of absolutely continuous invariant measures. We first prove an existence theorem for BV invariant densities for piecewise expanding maps on subsets of Rr; the maps must be C2, but may have infinitely many branches and need not be Markov. Under and additional “onto” assumption, explicit bounds on the spectral gap in the associated Perron-Frobenius operator are proved. The corresponding contraction rates are in the BV norm, rather than a projective metric. With this quantitative information, we are then able to prove convergence and explicit upper bounds on the approximation error in Ulam’s method for approximating invariant measures. Because the BV approach is rather concete, the methods of this paper can be applied in practice; this is illustrated by an application of the main results to the Jacobi-Perron transformation on R2

Overview of Deeply Virtual Compton Scattering at HERMES

Deeply Virtual Compton Scattering represents the best experimental channel through which to understand Generalised Parton Distributions. The HERMES experiment measured the most diverse set of DVCS results of any experiment; this talk discusses the most recent sets of DVCS results released by HERMES and the unique experimental conditions found at HERMES that facilitated the measurements. We also examine the various ways in which the HERMES experimental measurements are being used to constrain GPDs and how future experiments can learn from the HERMES program.Comment: 4 pages, 2 figures, prepared for DIS201