Review of the environmental and organisational implications of cloud computing: final report.

Cloud computing – where elastic computing resources are delivered over the Internet by external service providers – is generating significant interest within HE and FE. In the cloud computing business model, organisations or individuals contract with a cloud computing service provider on a pay-per-use basis to access data centres, application software or web services from any location. This provides an elasticity of provision which the customer can scale up or down to meet demand. This form of utility computing potentially opens up a new paradigm in the provision of IT to support administrative and educational functions within HE and FE. Further, the economies of scale and increasingly energy efficient data centre technologies which underpin cloud services means that cloud solutions may also have a positive impact on carbon footprints. In response to the growing interest in cloud computing within UK HE and FE, JISC commissioned the University of Strathclyde to undertake a Review of the Environmental and Organisational Implications of Cloud Computing in Higher and Further Education [19]

An economical vent cover

Inexpensive formed-plastic vent cover has been developed that allows controlled purge of vent systems and also provides blowout protection. Cover can also be used in relief mode to allow normal system relief flows without disengaging from vent system. Cover consists of two parts made of plastics with varying densities to fit media used and desired pressures

Modelling the alumina abundance of oxygen-rich evolved stars in the Large Magellanic Cloud

In order to determine the composition of the dust in the circumstellar envelopes of oxygen-rich asymptotic giant branch (AGB) stars we have computed a grid of modust radiative-transfer models for a range of dust compositions, mass-loss rates, dust shell inner radii and stellar parameters. We compare the resulting colours with the observed oxygen-rich AGB stars from the SAGE-Spec Large Magellanic Cloud (LMC) sample, finding good overall agreement for stars with a mid-infrared excess. We use these models to fit a sample of 37 O-rich AGB stars in the LMC with optically thin circumstellar envelopes, for which 5$-$35-$\mu$m Spitzer infrared spectrograph (IRS) spectra and broadband photometry from the optical to the mid-infrared are available. From the modelling, we find mass-loss rates in the range $\sim 8\times10^{-8}$ to $5\times10^{-6}$ M$_{\odot}\ \mathrm{yr}^{-1}$, and we show that a grain mixture consisting primarily of amorphous silicates, with contributions from amorphous alumina and metallic iron provides a good fit to the observed spectra. Furthermore, we show from dust models that the AKARI [11]$-$[15] versus [3.2]$-$[7] colour-colour diagram, is able to determine the fractional abundance of alumina in O-rich AGB stars.Comment: 22 pages, 17 figures, accepted MNRA

Broken Symmetry as a Stabilizing Remnant

The Goldberger-Wise mechanism enables one to stabilize the length of the warped extra dimension employed in Randall-Sundrum models. In this work we generalize this mechanism to models with multiple warped throats sharing a common ultraviolet brane. For independent throats this generalization is straight forward. If the throats possess a discrete interchange symmetry like Z_n the stabilizing dynamics may respect the symmetry, resulting in equal throat lengths, or they may break it. In the latter case the ground state of an initially symmetric configuration is a stabilized asymmetric configuration in which the throat lengths differ. We focus on two- (three-) throat setups with a Z_2 (Z_3) interchange symmetry and present stabilization dynamics suitable for either breaking or maintaining the symmetry. Though admitting more general application, our results are relevant for existing models in the literature, including the two throat model with Kaluza-Klein parity and the three throat model of flavor based on a broken Z_3 symmetry.Comment: 23 pages; v2 minor cosmetic chang

Coupling Non-Gravitational Fields with Simplicial Spacetimes

The inclusion of source terms in discrete gravity is a long-standing problem. Providing a consistent coupling of source to the lattice in Regge Calculus (RC) yields a robust unstructured spacetime mesh applicable to both numerical relativity and quantum gravity. RC provides a particularly insightful approach to this problem with its purely geometric representation of spacetime. The simplicial building blocks of RC enable us to represent all matter and fields in a coordinate-free manner. We provide an interpretation of RC as a discrete exterior calculus framework into which non-gravitational fields naturally couple with the simplicial lattice. Using this approach we obtain a consistent mapping of the continuum action for non-gravitational fields to the Regge lattice. In this paper we apply this framework to scalar, vector and tensor fields. In particular we reconstruct the lattice action for (1) the scalar field, (2) Maxwell field tensor and (3) Dirac particles. The straightforward application of our discretization techniques to these three fields demonstrates a universal implementation of coupling source to the lattice in Regge calculus.Comment: 10 pages, no figures, Latex, fixed typos and minor corrections

Termination shock particle spectral features

Spectral features of energetic H ions accelerated at the termination shock may be evidence of two components. At low energies the energy spectrum is ~E^(–1.55), with break at ~0.4 MeV to E^(–2.2). A second component appears above ~1 MeV with a spectrum of E^(–1.27) with a break at ~3.2 MeV. Even though the intensities upstream are highly variable, the same spectral break energies are observed, suggesting that these are durable features of the source spectrum. The acceleration processes for the two components may differ, with the lower energy component serving as the injection source for diffusive shock acceleration of the higher energy component. Alternatively, the spectral features may result from the energy dependence of the diffusion tensor that affects the threshold for diffusive shock acceleration

Voyager observations of galactic and anomalous cosmic rays in the helioshealth

Anomalous cosmic rays display large temporal variations at the time and location where Voyager 1 (V1) crossed the heliospheric termination shock (2004.86) (94AU, 34°N). On a short time scale (3 months) there was a large decrease produced by a series of merged interaction regions (MIR), the first of which was associated with the intense Oct./Nov. 2003 solar events. On a longer time scale there is a remarkable correlation between changes in the galactic cosmic ray (GCR) intensity and those of 10–56 MeV/n ACR He and 30–56 MeV H extending over a 4.3 year period with the GCRs exhibiting their expected behavior over this part of the 11 and 22 year solar activity and heliomagnetic cycle. The relative changes in the ACR and GCR are the same for both the short term and long term variations. The comparative V1/V2 ACR and GCR spectra in the foreshock and heliosheath indicate that at this time most of the higher energy ACRs are not being accelerated near V1 but must have their source region elsewhere — possibly near the equatorial region of the TS as was suggested in our first paper on the TS crossing (1)