Stable isotopic studies of H,C,N,O and S in samples of Martian origin

The present day geochemical cycles of volatile elements through the various reservoirs on Earth are largely understood within the context of the planet's standing as a geologically and biologically evolved body. In terrestrial studies stable isotope measurements of light elements (H, C, N, O and S) can be utilized to obtain insight into the conditions prevailing during formation of rocks of various types. Perhaps the most important problem which could be addressed by light element studies of the sorts of specimen likely to be available from remote automatic sampling, would be the role of volatiles during evolution. Of fundamental importance here is the question of whether Mars was volatile rich or volatile poor. The only way to fully comprehend the effects of volatile cycling through the mantle crust and regolith atmosphere polar cap system of Mars, is by analyses of appropriate returned samples. In order to interpret the record of geological activity in Martian samples it will be necessary to understand how the past, or present, surface environment may have acted to disturb the primary characteristics of the rocks

RadBench : benchmarking image interpretation skills

Purpose: The key aim of this research was to develop an objective, accurate assessment tool with which to provide regular measurement and monitoring of image interpretation performance. The tool was a specially developed software program (RadBench) by which to objectively measure image interpretation performance en masse and identify development needs. Method: Two test banks were generated (Test 1 & Test 2), each containing twenty appendicular musculoskeletal images, half were normal, half contained fractures. All images were double reported by radiologists and anonymised. A study (n ¼ 42) was carried out within one calendar month to test the method and analysis approach. The participants included general radiographers (34), reporting radiographers (3), radiologists (2) (all from one UK NHS Trust) and medical imaging academics (3). Results: The RadBench software generated calculations of sensitivity, specificity, and accuracy in addition to a decision making map for each respondent. Early findings highlighted a 5% mean difference between image banks, confirming that benchmarking must be related to a specific test. The benchmarking option within the software enabled the user to compare their score with the highest, lowest and mean score of others who had taken the same test. Reporting radiographers and radiologists all scored 95% or above accuracy in both tests. The general radiographer population scored between 60 and 95%. Conclusions: The evidence from this research indicates that the Radbench tool is capable of providing benchmark measures of image interpretation accuracy, with the potential for comparison across populations

Using visualization for visualization : an ecological interface design approach to inputting data

Visualization is experiencing growing use by a diverse community, with continuing improvements in the availability and usability of systems. In spite of these developments the problem of how first to get the data in has received scant attention: the established approach of pre-defined readers and programming aids has changed little in the last two decades. This paper proposes a novel way of inputting data for scientific visualization that employs rapid interaction and visual feedback in order to understand how the data is stored. The approach draws on ideas from the discipline of ecological interface design to extract and control important parameters describing the data, at the same time harnessing our innate human ability to recognize patterns. Crucially, the emphasis is on file format discovery rather than file format description, so the method can therefore still work when nothing is known initially of how the file was originally written, as is often the case with legacy binary data. © 2013 Elsevier Ltd

Global dimensions for the recognition of prototypical urban roads in large-scale vector topographic maps

CISRG discussion paper ; 1

Structural, vibrational and thermal properties of densified silicates : insights from Molecular Dynamics

Structural, vibrational and thermal properties of densified sodium silicate (NS2) are investigated with classical molecular dynamics simulations of the glass and the liquid state. A systematic investigation of the glass structure with respect to density was performed. We observe a repolymerization of the network manifested by a transition from a tetrahedral to an octahedral silicon environment, the decrease of the amount of non-bridging oxygen atoms and the appearance of three-fold coordinated oxygen atoms (triclusters). Anomalous changes in the medium range order are observed, the first sharp diffraction peak showing a minimum of its full-width at half maximum according to density. The previously reported vibrational trends in densified glasses are observed, such as the shift of the Boson peak intensity to higher frequencies and the decrease of its intensity. Finally, we show that the thermal behavior of the liquid can be reproduced by the Birch-Murnaghan equation of states, thus allowing us to compute the isothermal compressibility

A comparison of the excess mass around CFHTLenS galaxy-pairs to predictions from a semi-analytic model using galaxy-galaxy-galaxy lensing

The matter environment of galaxies is connected to the physics of galaxy formation and evolution. Utilising galaxy-galaxy-galaxy lensing as a direct probe, we map out the distribution of correlated surface mass-density around galaxy pairs for different lens separations in the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). We compare, for the first time, these so-called excess mass maps to predictions provided by a recent semi-analytic model, which is implanted within the dark-matter Millennium Simulation. We analyse galaxies with stellar masses between $10^9-10^{11}\,{\rm M}_\odot$ in two photometric redshift bins, for lens redshifts $z\lesssim0.6$, focusing on pairs inside groups and clusters. To allow us a better interpretation of the maps, we discuss the impact of chance pairs, i.e., galaxy pairs that appear close to each other in projection only. Our tests with synthetic data demonstrate that the patterns observed in the maps are essentially produced by correlated pairs that are close in redshift ($\Delta z\lesssim5\times10^{-3}$). We also verify the excellent accuracy of the map estimators. In an application to the galaxy samples in the CFHTLenS, we obtain a $3\sigma-6\sigma$ significant detection of the excess mass and an overall good agreement with the galaxy model predictions. There are, however, a few localised spots in the maps where the observational data disagrees with the model predictions on a $\approx3.5\sigma$ confidence level. Although we have no strong indications for systematic errors in the maps, this disagreement may be related to the residual B-mode pattern observed in the average of all maps. Alternatively, misaligned galaxy pairs inside dark matter halos or lensing by a misaligned distribution of the intra-cluster gas might also cause the unanticipated bulge in the distribution of the excess mass between lens pairs.Comment: 21 pages, 12 figures; abridged abstract; revised version for A&A after addressing all comments by the refere