4,150 research outputs found
Colin Humphris
No full text"Colin Humphris 2 Sqdrn. RAAF. 1941 - 1942 Author of - 'Trapped on Timor' (as a result of bombing of Darwin Feb. 19, 1942)".Colin Humphris. 2 Squadron, Royal Australian Air Force 1941 - 1942. Author of - 'Trapped on Timor' (as a result of bombing of Darwin February 19, 1942)
Morning: Juliet Ellis
No full textA short documentary profile of Juliet Ellis, the Writer and Director of the feature film, Morning. Exploring the development of the film and the beginnings of her collaboration with the Producer, Colin Pons
A stratigraphical basis for the Anthropocene?
No full textRecognition of intimate feedback mechanisms linking changes across the atmosphere, biosphere, geosphere and hydrosphere demonstrates the pervasive nature of humankind's influence, perhaps to the point that we have fashioned a new geological epoch, the Anthropocene. To what extent will these changes be evident as long-lasting signatures in the geological record?
To establish the Anthropocene as a formal chronostratigraphical unit it is necessary to consider a spectrum of indicators of anthropogenically induced environmental change, and to determine how these show as stratigraphic signals that can be used to characterize an Anthropocene unit and to recognize its base. It is important to consider these signals against a context of Holocene and earlier stratigraphic patterns. Here we review the parameters used by stratigraphers to identify chronostratigraphical units and how these could apply to the definition of the Anthropocene. The onset of the range of signatures is diachronous, although many show maximum signatures which post-date1945, leading to the suggestion that this date may be a suitable age for the start of the Anthropocene
Colin Fraser
No full textPhotograph - Colin Fraser (third from right) in a loaded scow leaving for Fort Chipewyan from Athabasca, Alberta. A group of men are also standing on the pie
Ribozyme catalysis with a twist: active state of the twister ribozyme in solution predicted from molecular simulation
No full textWe present results from molecular dynamics simulations and free energy calculations of the twister ribozyme at different stages along the reaction path to gain insight into its mechanism. The results, together with recent biochemical experiments, provide support for a mechanism involving general-acid catalysis by a conserved adenine residue in the active site. Although adenine has been previously implicated as a general acid acting through the N1 position in other ribozymes such as the hairpin and VS ribozymes, in the twister ribozyme there may be a twist. Biochemical experiments suggest that general acid catalysis may occur through the N3 position, which has never before been implicated in this role; however, currently, there is a lack of a detailed structural model for the active state of the twister ribozyme in solution that is consistent with these and other experiments. Simulations in a crystalline environment reported here are consistent with X-ray crystallographic data, and suggest that crystal packing contacts trap the RNA in an inactive conformation with U-1 in an extruded state that is incompatible with an in-line attack to the scissile phosphate. Simulations in solution, on the other hand, reveal this region to be dynamic and able to adopt a conformation where U-1 is stacked with G33. In this state, the nucleophile is in line with the scissile phosphate, and the N1 position of G33 and N3 position of A1 are poised to act as a general base and acid, respectively, as supported by mutational experiments. Free energy calculations further predict the electrostatic environment causes a shift of the microscopic pKa at the N3 position of A1 toward neutrality by approximately 5 pKa units. These results offer a unified interpretation of a broad range of currently available experimental data that points to a novel mode of general acid catalysis through the N3 position of an adenine nucleobase, thus expanding the repertoire of known mechanistic strategies employed by small nucleolytic ribozymes.Peer reviewe
Spatially Continuous Depletion Algorithm for Monte Carlo Simulations
No full textTo correctly predict reactor behavior during cycle operations, the evolution of nuclide number densities throughout the core must be accurately modeled. The time-varying spatial distribution of nuclide number densities is typically resolved by discretizing the Monte Carlo geometry into smaller cells over which number densities are assumed to be spatially invariant.
The nuclide number densities in these smaller cells are integrated through time using reaction rate tallies on the same discretized geometry. However, detailed distributions of nuclide number densities in a full three dimensional simulation can require a prohibitive amount of tallies, and the spatial
discretization of the base geometry makes coupling to external multiphysics tools difficult. In this paper a method for solving for spatially continuous number density distributions during depletion calculations
will be described. The spatially continuous number densities can be used in the transport method proposed by Brown and Martin which allows for transporting neutrons through a material with continuously varying properties such as temperature and nuclide number densities. Coupled with the ability of Functional Expansion Tallies (FETs) [2] to represent tallied quantities as continuous functions, it is possible to both solve for and make use of spatially continuous nuclide number densities. The need for this capability was alluded to by Brown et. al., but no solution has yet been proposed. With a continuous depletion method, recent work which utilized
FETs and continuous material tracking to incorporate multiphysics
feedback in Monte Carlo simulations can be extended to simulations that include depletion analysis.United States. Department of Energy (Nuclear Energy University Programs Graduate Fellowship
Orbit design for future SpaceChip swarm missions in a planetary atmosphere
No full textThe effect of solar radiation pressure and atmospheric drag on the orbital dynamics of satellites-on-a-chip (SpaceChips) is exploited to design equatorial long-lived orbits about the oblate Earth. The orbit energy gain due to asymmetric solar radiation pressure, considering the Earth's shadow, is used to balance the energy loss due to atmospheric drag. Future missions for a swarm of SpaceChips are proposed, where a number of small devices are released from a conventional spacecraft to perform spatially distributed measurements of the conditions in the ionosphere and exosphere. It is shown that the orbit lifetime can be extended and indeed selected through solar radiation pressure and the end-of-life re-entry of the swarm can be ensured, by exploiting atmospheric drag
Supplemental_Material - Cerebrospinal Fluid in Posterior Reversible Encephalopathy Syndrome: Implications of Elevated Protein and Pleocytosis
No full textSupplemental_Material for Cerebrospinal Fluid in Posterior Reversible Encephalopathy Syndrome: Implications of Elevated Protein and Pleocytosis by Colin A. Ellis, Andrew C. McClelland, Suyash Mohan, Emory Kuo, Scott E. Kasner, Cen Zhang, Pouya Khankhanian, and Ramani Balu in The Neurohospitalist</p
Morning: A Producers POV
No full textA documentary about the making of Morning, written and Directed by Juliet Ellis, a feature film shot in Sheffield in the Summer of 2017. Made by Christopher Hall and Colin Pons the documentary uniquely charts the production from the Producers perspective.
Both the feature and the documentary involved collaboration with MA Filmmaking students in various roles.
This version of the documentary was produced for RAISE 2018
Inside which circle? A reply to Colin Bundy
No full textThe author contests Colin Bundy's recent characterisation of the inapplicability of colonialism of a special type theory to South Africa
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