A conceptual approach for estimating resilience to fuel shocks

We examine a conceptual approach to the estimation of resilience of transport systems to fuel shocks, i.e. a severe and long lasting reduction in the availability of fuel for motorised transport. Adaptive capacity is an element of resilience and is defined in the paper. There is currently no indicator of adaptive capacity of individuals in small geographies sensitive to a variety of policy measures, such as those affecting fitness, obesity, bicycle availability and bicycle infrastructure, whose impacts (at least in the short term) are on a smaller scale than large-scale land use and urban morphology change. We propose a conceptual approach for designing a method to quantify this indicator. The indicator shows the proportion of the population of areas who would have the capacity to commute to work principally by bicycle or walking following the shock. It assesses capacity grounded in current data and avoids as far as possible the need for speculation about the future. We believe this makes progress towards producing a good indicator with relatively un-controversial, transparent simplifying assumptions. The indicator can compare the resilience of different areas and can be updated over time

Pathways to achieving radically different urban walking and cycling futures in the UK by 2030

This paper builds upon earlier work which was presented at Walk21 in 2009 and 2010 which outlined the development of a number of radically different visions for the role of walking and cycling in urban areas in the year 2030. These visions, which were developed through consultation with a wide range of stakeholders, present a 2030 where walking and cycling play a significantly greater role in urban transportation than is currently the case, accounting for as much as 80% of urban trips in the most extreme vision. Previous reported work had focussed on the kinds of measures, contextual background and lifestyle changes which would be required to support such visions, how urban areas may appear and the practicalities of daily life. Subsequent research (not yet reported in the public domain) has developed methods for constructing pathways to show how these visions might be reached. A pathway (in a specific city) to the successful occurrence of a vision is defined as being made up of a combination of developments on two separate levels: a Macro level , involving both developments external to the transport system and developments within the transport system but “out of control” of the local authority of the city concerned ; and a Micro level, involving developments within the control of the city’s local authority. The trajectory of developments on a particular level is referred to as a ‘storyline’, so that a distinction is made between Macro - storylines and Micro- storylines. Whilst generic macro - storylines have been developed which are relevant to all UK cities, micro - storylines can only be constructed ‘locally’ by those with sufficient knowledge of a particular city. The focus of the current paper is upon two workshops carried out in the summer of 2011 in the UK cities of Leeds and Norwich. The main purpose of these workshops was to explore how one of the visions could be mapped/adapted to their specific local circumstances and to develop pathways for achieving this vision, taking into account three alternative macro - storylines. The workshops aimed to attract relatively senior people from the local authorities in each area and representatives of stakeholder groups . The workshop size was between 10 - 15 people. The underlying aim of such exercises is to encourage city authorities and stakeholders to think in a more structured, systematic way about how the various potentially -conflicting issues concerning walking and cycling would play out in a long - term future, taking into account that the ‘external environment’ (e.g. the national economy) is highly unpredictable. The paper presents the results from the Leeds and Norwich workshops in terms of the local visions and pathways that they produced. Special attention is paid to results concerned with policies that directly facilitate walking, whilst recognising that a large number of factors (all urban transport modes, land use patterns, ‘society’) have impacts (direct or indirect) on walking. Various conclusions are presented, both with regard to transport policy and the methodology for constructing the visions/pathways and running the workshops

A cancer cell-line titration series for evaluating somatic classification.

BackgroundAccurate detection of somatic single nucleotide variants and small insertions and deletions from DNA sequencing experiments of tumour-normal pairs is a challenging task. Tumour samples are often contaminated with normal cells confounding the available evidence for the somatic variants. Furthermore, tumours are heterogeneous so sub-clonal variants are observed at reduced allele frequencies. We present here a cell-line titration series dataset that can be used to evaluate somatic variant calling pipelines with the goal of reliably calling true somatic mutations at low allele frequencies.ResultsCell-line DNA was mixed with matched normal DNA at 8 different ratios to generate samples with known tumour cellularities, and exome sequenced on Illumina HiSeq to depths of >300×. The data was processed with several different variant calling pipelines and verification experiments were performed to assay >1500 somatic variant candidates using Ion Torrent PGM as an orthogonal technology. By examining the variants called at varying cellularities and depths of coverage, we show that the best performing pipelines are able to maintain a high level of precision at any cellularity. In addition, we estimate the number of true somatic variants undetected as cellularity and coverage decrease.ConclusionsOur cell-line titration series dataset, along with the associated verification results, was effective for this evaluation and will serve as a valuable dataset for future somatic calling algorithm development. The data is available for further analysis at the European Genome-phenome Archive under accession number EGAS00001001016. Data access requires registration through the International Cancer Genome Consortium's Data Access Compliance Office (ICGC DACO)

Atomic Scale Depth Profile of Space Weathering in an Itokawa Olivine Grain

No abstract available

Enhanced diffusion of Uranium and Thorium linked to crystal plasticity in zircon

The effects of crystal-plasticity on the U-Th-Pb system in zircon is studied by quantitative microstructural and microchemical analysis of a large zircon grain collected from pyroxenite of the Lewisian Complex, Scotland. Electron backscatter diffraction (EBSD) mapping reveals a c.18° variation in crystallographic orientation that comprises both a gradual change in orientation and a series of discrete low-angle (<4°) boundaries. These microstructural data are consistent with crystal-plastic deformation of zircon associated with the formation and migration of dislocations. A heterogeneous pattern of dark cathodoluminescence, with the darkest domains coinciding with low-angle boundaries, mimics the deformation microstructure identified by EBSD. Geochemical data collected using the Sensitive High Resolution Ion MicroProbe (SHRIMP) shows a positive correlation between concentrations of the elements U, Th and Pb (ranging from 20–60 ppm, 30–110 ppm, and 14–36 ppm, respectively) and Th/U ratio (1.13 – 1.8) with the deformation microstructure. The highest measured concentrations and Th/U coincide with low-angle boundaries. This enrichment is interpreted to reflect enhanced bulk diffusion of U and Th due to the formation and migration of high-diffusivity dislocations. (207)Pb/(206)Pb ages for individual analyses show no significant variation across the grain, and define a concordant, combined mean age of 2451 ± 14 Ma. This indicates that the grain was deformed shortly after initial crystallization, most probably during retrograde Inverian metamorphism at amphibolite facies conditions. The elevated Th over U and consistent (207)Pb/(206)Pb ages indicates that deformation most likely occurred in the presence of a late-stage magmatic fluid that drove an increase in the Th/U during deformation. The relative enrichment of Th over U implies that Th/U ratio may not always be a robust indicator of crystallization environment. This study provides the first evidence of deformation-related modification of the U-Th system in zircon and has fundamental implications for the application and interpretation of zircon trace element data

Energy-saving compression valve of the rock drill

The relevance of the research is due to the necessity to create pneumatic rock drills with low air consumption. The article analyzes the reasons for low efficiency of percussive machines. The authors state that applying a single distribution body in the percussive mechanism does not allow carrying out a low-energy operating cycle of the mechanism. Using the studied device as an example, it is substantiated that applying a compression valve with two distribution bodies separately operating the working chambers makes it possible to significantly reduce the airflow. The authors describe the construction of a core drill percussive mechanism and the operation of a compression valve. It is shown that in the new percussive mechanism working chambers are cut off the circuit by the time when exhaust windows are opened by the piston and air is not supplied into the cylinder up to 20% of the cycle time. The air flow rate of the new mechanism was 3.8 m3/min. In comparison with the drill PK-75, the overall noise level of the new machine is lower by 8-10 dB, while the percussive mechanism efficiency is 2.3 times higher

Exploring the relative contribution of mineralogy and CPO to the seismic velocity anisotropy of evaporites

We present the influence of mineralogy and microstructure on the seismic velocity anisotropy ofevaporites. Bulk elastic properties and seismic velocities are calculated for a suite of 20 natural evaporate samples, which consist mainly of halite, anhydrite, and gypsum. They exhibit strong fabrics as a result of tectonic and diagenetic processes. Sample mineralogy and crystallographic preferred orientation (CPO) were obtained with the electron backscatter diffraction (EBSD) technique and the data used for seismic velocity calculations. Bulk seismic properties for polymineralic evaporites were evaluated with a rock recipe approach. Ultrasonic velocity measurements were also taken on cube shaped samples to assess the contribution of grain-scale shape preferred orientation (SPO) to the total seismic anisotropy. The sample results suggest that CPO is responsible for a significant fraction of the bulk seismic properties, in agreement with observations from previous studies. Results from the rock recipe indicate that increasing modal proportion of anhydrite grains can lead to a greater seismic anisotropy of a halite-dominated rock.Conversely, it can lead to a smaller seismic anisotropy degree of a gypsum-dominated rock until anestimated threshold proportion after which anisotropy increases again. The difference between thepredicted anisotropy due to CPO and the anisotropy measured with ultrasonic velocities is attributed to the SPO and grain boundary effects in these evaporites

Rapid hydration and weakening of anhydrite under stress: implications for natural hydration in the Earth's crust and mantle

Mineral hydration is an important geological process that influences the rheology and geochemistry of rocks and the fluid budget of the Earth's crust and mantle. Constant-stress differential compaction (CSDC) tests, dry and "wet"tests under confining pressure, and axial-stress tests were conducted for the first time to investigate the influence of triaxial stress on hydration in anhydrite-gypsum aggregates. Characterization of the samples before and after triaxial experiments was performed with optical and scanning electron microscopy, including energy-dispersive spectroscopy and electron backscatter diffraction mapping. Stress-strain data reveal that samples that underwent constant-stress differential compaction in the presence of fluids are g1/4g14g% to g1/4g41g% weaker than samples deformed under wet conditions. The microstructural analysis shows that there is a strong temporal and spatial connection between the geometry, distribution, and evolution of fractures and hydration products. The increasing reaction surface area in combination with pre-existing gypsum in a gypsum-bearing anhydrite rock led to rapid gypsification. The crystallographic orientations of newly formed vein gypsum have a systematic preferred orientation for long distances along veins, beyond the grain boundaries of wall-rock anhydrite. Gypsum crystallographic orientations in {100} and {010} are systematically and preferentially aligned parallel to the direction of maximum shear stress (45g to σ1). Gypsum is also not always topotactically linked to the wall-rock anhydrite in the immediate vicinity. This study proposes that the selective inheritance of crystal orientations from favourably oriented wall-rock anhydrite grains for the minimization of free energy for nucleation under stress leads to the systematic preferred orientation of large, new gypsum grains. A sequence is suggested for hydration under stress that requires the development of fractures accompanied by localized hydration. Hydration along fractures with a range of apertures up to 120gμm occurred in under 6gh. Once formed, gypsum-filled veins represent weak surfaces and are the locations of further shear fracturing, brecciation, and eventual brittle failure. These findings imply that non-hydrostatic stress has a significant influence on hydration rates and subsequent mechanical strength of rocks. This phenomenon is applicable across a wide range of geological environments in the Earth's crust and upper mantle

Atomic kinetic energy, momentum distribution and structure of solid neon at zero-temperature

We report on the calculation of the ground-state atomic kinetic energy, $E_{k}$, and momentum distribution of solid Ne by means of the diffusion Monte Carlo method and Aziz HFD-B pair potential. This approach is shown to perform notably for this crystal since we obtain very good agreement with respect to experimental thermodynamic data. Additionally, we study the structural properties of solid Ne at densities near the equilibrium by estimating the radial pair-distribution function, Lindemann's ratio and atomic density profile around the positions of the perfect crystalline lattice. Our value for $E_{k}$ at the equilibrium density is $41.51(6)$ K, which agrees perfectly with the recent prediction made by Timms {\it et al.}, $41(2)$ K, based on their deep-inelastic neutron scattering experiments carried out over the temperature range $4 - 20$ K, and also with previous path integral Monte Carlo results obtained with the Lennard-Jones and Aziz HFD-C2 atomic pairwise interactions. The one-body density function of solid Ne is calculated accurately and found to fit perfectly, within statistical uncertainty, to a Gaussian curve. Furthermore, we analyze the degree of anharmonicity of solid Ne by calculating some of its microscopic ground-state properties within traditional harmonic approaches. We provide insightful comparison to solid $^4$He in terms of the Debye model, in order to size the relevance of anharmonic effects in Ne.Comment: 20 pages, 7 figures. To be published in Physical Review