Gold in Devono-Carboniferous red beds of northern Britain

We are grateful to D. Craw and an anonymous reviewer for comments that helped to clarify the paper. Research was funded by NERC grants NE/L001764/1 and NE/M010953/1.Peer reviewedPublisher PD

Imaging starspot evolution on Kepler target KIC 5110407 using light curve inversion

The Kepler target KIC 5110407, a K-type star, shows strong quasi-periodic light curve fluctuations likely arising from the formation and decay of spots on the stellar surface rotating with a period of 3.4693 days. Using an established light-curve inversion algorithm, we study the evolution of the surface features based on Kepler space telescope light curves over a period of two years (with a gap of .25 years). At virtually all epochs, we detect at least one large spot group on the surface causing a 1-10% flux modulation in the Kepler passband. By identifying and tracking spot groups over a range of inferred latitudes, we measured the surface differential rotation to be much smaller than that found for the Sun. We also searched for a correlation between the seventeen stellar flares that occurred during our observations and the orientation of the dominant surface spot at the time of each flare. No statistically-significant correlation was found except perhaps for the very brightest flares, suggesting most flares are associated with regions devoid of spots or spots too small to be clearly discerned using our reconstruction technique. While we may see hints of long-term changes in the spot characteristics and flare statistics within our current dataset, a longer baseline of observation will be needed to detect the existence of a magnetic cycle in KIC 5110407.Comment: 32 pages, 15 figures, accepted to Ap

Niobium mineralization of sedimentary carbonates, Lewisian Complex, UK

Funding This work was supported by the NERC under Grant NE/M010953/1. Acknowledgements Skilled technical support was provided by J. Johnston and J. Bowie. We are very grateful to three reviewers whose comments helped to focus the manuscript. Conceptualization, J.P.; Formal Analysis, J.S., E.H. and J.P.; Investigation, R.M., E.H., J.S. and J.P.; Data Curation, J.S.; Writing, Review & Editing, J.P., E.H. and R.M.; Project Administration, J.P.; Funding Acquisition, J.P. Open access via T&F agreementPeer reviewedPublisher PD

Examining the Influence of Saliency in Mobile Interface Displays

Designers spend more resources to develop better mobile experiences today than ever before. Researchers commonly use visual search efficiency as a usability measure to determine the time or effort it takes someone to perform a task. Previous research has shown that a computational visual saliency model can predict attentional deployment in stationary desktop displays. Designers can use this salience awareness to co-locate important task information with higher salience regions. Research has shown that placing targets in higher salience regions in this way improves interface efficiency. However, researchers have not tested the model in key mobile technology design dimensions such as small displays and touch screens. In two studies, we examined the influence of saliency in a mobile application interface. In the first study, we explored a saliency model’s ability to predict fixations in small mobile interfaces at three different display sizes under free-viewing conditions. In the second study, we examined the influence that visual saliency had on search efficiency while participants completed a directed search for either an interface element associated with high or low salience. We recorded reaction time to touch the targeted element on the tablet. We experimentally blocked high and low saliency interactions and subjectively measured cognitive workload. We found that a saliency model predicted fixations. In the search task, participants found highly salient targets about 900 milliseconds faster than low salient targets. Interestingly, participants did not perceive a lighter cognitive workload associated with the increase in search efficiency

Selenium and tellurium resources in Kisgruva Proterozoic volcanogenic massive sulphide deposit (Norway)

The authors are extremely grateful to Kåre Kullerud of the Norsk Bergverksmuseum (Kongsberg) for sharing his wealth of knowledge of the Kisgruva site and assisting in accessibility. The authors also wish to thank Abbie Mclaughlin (University of Aberdeen) for her assistance with XRD analysis. The authors thank the anonymous reviewers for their careful reading and corrections of the manuscript. Funding This work was supported by the UK Natural Environment Research Council (NERC); Minerals Security of Supply (SoS) Grant NE/M010953/1, Tellurium and Selenium Cycling and Supply (TeaSe).Peer reviewedPublisher PD

FUSE Observations of a Full Orbit of Hercules X-1: Signatures of Disk, Star, and Wind

We observed an entire 1.7 day orbit of the X-ray binary Hercules X-1 with the Far Ultraviolet Spectroscopic Explorer (FUSE). Changes in the O VI 1032,1037 line profiles through eclipse ingress and egress indicate a Keplerian accretion disk spinning prograde with the orbit. These observations may show the first double-peaked accretion disk line profile to be seen in the Hercules X-1 system. Doppler tomograms of the emission lines show a bright spot offset from the Roche lobe of the companion star HZ Her, but no obvious signs of the accretion disk. Simulations show that the bright spot is too far offset from the Roche lobe to result from uneven X-ray heating of its surface. The absence of disk signatures in the tomogram can be reproduced in simulations which include absorption from a stellar wind. We attempt to diagnose the state of the emitting gas from the C III 977, C III 1175, and N III 991 emission lines. The latter may be enhanced through Bowen fluorescence.Comment: Accepted for publication in The Astrophysical Journa

Accelerator performance analysis of the Fermilab Muon Campus

Fermilab is dedicated to hosting world-class experiments in search of new physics that will operate in the coming years. The Muon g-2 Experiment is one such experiment that will determine with unprecedented precision the muon anomalous magnetic moment, which offers an important test of the Standard Model. We describe in this study the accelerator facility that will deliver a muon beam to this experiment. We first present the lattice design that allows for efficient capture, transport, and delivery of polarized muon beams. We then numerically examine its performance by simulating pion production in the target, muon collection by the downstream beam line optics, as well as transport of muon polarization. We finally establish the conditions required for the safe removal of unwanted secondary particles that minimizes contamination of the final beam.Comment: 10 p

Kepler Observations of V447 Lyr: An Eclipsing U Gem Cataclysmic Variable

We present the results of an analysis of data covering 1.5 years of the dwarf nova V447 Lyr. We detect eclipses of the accretion disk by the mass donating secondary star every 3.74 hrs which is the binary orbital period. V447 Lyr is therefore the first dwarf nova in the Kepler field to show eclipses. We also detect five long outbursts and six short outbursts showing V447 Lyr is a U Gem type dwarf nova. We show that the orbital phase of the mid-eclipse occurs earlier during outbursts compared to quiescence and that the width of the eclipse is greater during outburst. This suggests that the bright spot is more prominent during quiescence and that the disk is larger during outburst than quiescence. This is consistent with an expansion of the outer disk radius due to the presence of high viscosity material associated with the outburst, followed by a contraction in quiescence due to the accretion of low angular momentum material. We note that the long outbursts appear to be triggered by a short outburst, which is also observed in the super-outbursts of SU UMa dwarf novae as observed using Kepler.Comment: Accepted by MNRA

Information engine in a nonequilibrium bath

Information engines can convert thermal fluctuations of a bath at temperature $T$ into work at rates of order $k_\mathrm{B}T$ per relaxation time of the system. We show experimentally that such engines, when in contact with a bath that is out of equilibrium, can extract much more work. We place a heavy, micron-scale bead in a harmonic potential that ratchets up to capture favorable fluctuations. Adding a fluctuating electric field increases work extraction up to ten times, limited only by the strength of applied field. Our results connect Maxwell's demon with energy harvesting and an estimate of efficiency shows that information engines in nonequilibrium baths can greatly outperform conventional engines.Comment: 14 pages, 9 figure