6,194 research outputs found

    Validating the use of intrinsic markers in body feathers to identify inter-individual differences in non-breeding areas of northern fulmars

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    Acknowledgments We thank Claire Deacon, Gareth Norton and Andrea Raab for help with laboratory work at the University of Aberdeen, and Barry Thornton and Gillian Martin for running stable isotope analysis at the James Hutton Institute. Thanks to all involved in the collection and processing of dead fulmars through the North Sea plastic pollution project at IMARES, with special thanks to Jens-Kjeld Jensen, Bergur Olsen and Elisa Bravo Rebolledo for samples from the Faroe Islands and Susanne KĆ¼hn for those from Iceland. Thanks to Orkney Islands Council for access to Eynhallow and to all the fieldworkers involved in deployment and recovery of the GLS tags. All ringing work was carried out under permit from the BTO, and feather sampling was carried out under licence from the Home Office. We are grateful to James Fox of Migrate Technologies for recovering data from GLS loggers which would not download, and Richard Phillips and Janet Silk of BAS for advice on GLS analysis. We thank Deborah Dawson of the NERC Biomolecular Analysis Facility, University of Sheffield and Stuart Piertney of University of Aberdeen for molecular sexing of the fulmars. Lucy Quinn was supported by a NERC Studentship and additional funding to support fieldwork was gratefully received from Talisman Energy (UK) Ltd. We thank Yves Cherel and two anonymous reviewers for their constructive comments on the manuscript.Peer reviewedPublisher PD

    The applicability of self-regulation theories in sport : goal adjustment capacities, stress appraisals, coping and well-being among athletes

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    Objectives: We examined a model, informed by self-regulation theories, which included goal adjustment capacities, appraisals of challenge and threat, coping, and well-being. Design: Prospective. Methods: Two hundred and twelve athletes from the United Kingdom (n = 147) or Australia (n = 65), who played team (n = 135) or individual sports (n = 77), and competed at international (n = 7), national (n = 11), county (n = 67), club (n = 84), or beginner (n = 43) levels participated in this study. Participants completed measures of goal adjustment capacities and stress appraisals two days before competing. Athletes also completed questions on coping and well-being within three hours of their competition ending. Results: The way an athlete responds to an unattainable goal is associated with his or her well-being in the period leading up to and including the competition. Goal reengagement positively predicted well-being, whereas goal disengagement negatively predicted well-being. Further, goal reengagement was positively associated with challenge appraisals, which in turn was linked to task-oriented coping, and task-oriented coping positively associated with well-being. Conclusion: When highly-valued goals become unattainable, consultants could encourage athletes to seek out alternative approaches to achieve the same goal or help them develop a completely new goal

    Lagrangian pathways of upwelling in the Southern Ocean

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    The spatial and temporal variability of upwelling into the mixed layer in the Southern Ocean is studied using a 1/10Ā° ocean general circulation model. Virtual drifters are released in a regularly-spaced pattern across the Southern Ocean at depths of 250, 500, and 1000 m during both summer and winter months. The drifters are advected along isopycnals for a period of four years, unless they outcrop into the mixed layer, where lateral advection and a parameterization of vertical mixing is applied. The focus of this study is on the discrete exchange between the model mixed layer and the interior. Localization of interior-mixed layer exchange occurs downstream of major topographic features across the Indian and Pacific basins, creating ā€œhotspotsā€ of outcropping. Minimal outcropping occurs in the Atlantic basin, while 59% of drifters outcrop in the Pacific sector and in Drake Passage (the region from 140Ā° W to 40Ā° W), a disproportionately large amount even when considering the relative basin sizes. Due to spatial and temporal variations in mixed layer depth, the Lagrangian trajectories provide a statistical measure of mixed layer residence times. For each exchange into the mixed layer, the residence time has a Rayleigh distribution with a mean of 30 days; the cumulative residence time of the drifters is 261ā€‰Ā±ā€‰194 days, over a period of four years. These results suggest that certain oceanic gas concentrations, such as CO_2 and ^(14)C, will likely not reach equilibrium with the atmosphere before being re-subducted

    The rotation and Galactic kinematics of mid M dwarfs in the Solar Neighborhood

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    Rotation is a directly-observable stellar property, and drives magnetic field generation and activity through a magnetic dynamo. Main sequence stars with masses below approximately 0.35Msun (mid-to-late M dwarfs) are fully-convective, and are expected to have a different type of dynamo mechanism than solar-type stars. Measurements of their rotation rates provide insights into these mechanisms, but few rotation periods are available for these stars at field ages. Using photometry from the MEarth transit survey, we measure rotation periods for 387 nearby, mid-to-late M dwarfs in the Northern hemisphere, finding periods from 0.1 to 140 days. The typical detected rotator has stable, sinusoidal photometric modulations at a semi-amplitude of 0.5 to 1%. We find no period-amplitude relation for stars below 0.25Msun and an anti-correlation between period and amplitude for higher-mass M dwarfs. We highlight the existence of older, slowly-rotating stars without H{\alpha} emission that nevertheless have strong photometric variability. The Galactic kinematics of our sample is consistent with the local population of G and K dwarfs, and rotators have metallicities characteristic of the Solar Neighborhood. We use the W space velocities and established age-velocity relations to estimate that stars with P<10 days are on average <2 Gyrs, and that those with P>70 days are about 5 Gyrs. The period distribution is mass dependent: as the mass decreases, the slowest rotators at a given mass have longer periods, and the fastest rotators have shorter periods. We find a lack of stars with intermediate rotation periods. [Abridged]Comment: Accepted to ApJ. Machine readable tables and additional figures are available in the published article or on reques

    Growth and kinetic Monte Carlo simulation of InAs quantum wires on vicinal substrates

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    AbstractSelf-assembled quantum structures have been successfully grown for some time now but control over their uniformity has proven difficult due to the stochastic nature of surface diffusion. We have investigated the effect of vicinal InP(001) substrates on the uniformity of InAs quantum wires grown on InGaAlAs lattice-matched to InP using molecular beam epitaxy. Dense quantum wires were grown on both nominally flat and vicinal substrates off-cut by 0.9Ā° toward the [110] direction for comparison. The off-cut angle was chosen to provide terraces which match the orientation and spacing of wires grown on nominally flat substrates. A modest but statistically significant improvement in the size distribution of the wires was observed on vicinal substrates through the analysis of ultrahigh resolution scanning electron micrographs. The interface between the wires and the off-cut substrate was studied using cross-sectional high resolution scanning transmission electron microscopy. In addition, a kinetic Monte Carlo model of epitaxial growth including full strain calculations was developed to further investigate the nucleation process. Using an anisotropic bond model to account for the surface energy of different crystallographic facets, our simulations produced wires similar to those observed experimentally while demonstrating the importance of anisotropic bonding compared to anisotropic diffusion. Growth on vicinal substrates is also simulated here and indicates that off-cut substrates should indeed improve the size distribution of quantum wires under proper growth conditions

    Extreme asteroids in the Pan-STARRS 1 Survey

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    Using the first 18 months of the Pan-STARRS 1 survey we have identified 33 candidate high-amplitude objects for follow-up observations and carried out observations of 22 asteroids. 4 of the observed objects were found to have observed amplitude Aobsā‰„1.0A_{obs}\geq 1.0 mag. We find that these high amplitude objects are most simply explained by single rubble pile objects with some density-dependent internal strength, allowing them to resist mass shedding even at their highly elongated shapes. 3 further objects although below the cut-off for 'high-amplitude' had a combination of elongation and rotation period which also may require internal cohesive strength, depending on the density of the body. We find that none of the 'high-amplitude asteroids' identified here require any unusual cohesive strengths to resist rotational fission. 3 asteroids were sufficiently observed to allow for shape and spin pole models to be determined through light curve inversion. 45864 was determined to have retrograde rotation with spin pole axes Ī»=218Ā±10āˆ˜,Ī²=āˆ’82Ā±5āˆ˜\lambda=218\pm 10^{\circ}, \beta=-82\pm 5^{\circ} and asteroid 206167 was found to have best fit spin pole axes Ī»=57Ā±5āˆ˜\lambda= 57 \pm 5^{\circ}, Ī²=āˆ’67Ā±5āˆ˜\beta=-67 \pm 5^{\circ}. An additional object not initially measured with Aobs>1.0A_{obs}>1.0 mag, 49257, was determined to have a shape model which does suggest a high-amplitude object. Its spin pole axes were best fit for values Ī»=112Ā±6āˆ˜,Ī²=6Ā±5āˆ˜\lambda=112\pm 6^{\circ}, \beta=6\pm 5^{\circ}. In the course of this project to date no large super-fast rotators (Prot<2.2P_{rot} < 2.2 h) have been identified.Comment: 31 pages; accepted by A

    Onion gene expression in response to ethylene and 1-MCP

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    Onion is regarded as a non-climacteric vegetable. In onions, however, ethylene can suppress sprouting while the ethylene binding inhibitor, 1-MCP (1- methylcyclopropene) can also suppress sprout growth yet, it is unknown how ethylene and 1-MCP elicit the same response. In this study, onions were treated with 10 Ī¼L L-1 ethylene or 1 Ī¼L L-1 1-MCP individually or in combination for 24 h at 20Ā°C before or after curing (six weeks) at 20 or 28Ā°C then stored at 1Ā°C. Following curing, a subset of these same onions was stored separately under continuous air or ethylene (10 Ī¼L L- 1) at 1Ā°C Onions treated with ethylene and 1-MCP in combination after curing for 24 h had reduced sprout growth as compared with the control 25 weeks after harvest. Sprout growth following storage beyond 25 weeks was only reduced through continuous ethylene treatment. This observation was supported by a higher proportion of down-regulated genes characterised as being involved in photosynthesis measured using a newly developed onion microarray. Physiological and biochemical data suggested that ethylene was being perceived in the presence of 1-MCP since sprout growth was reduced in onions treated with 1-MCP and ethylene applied in combination but not when applied individually. A cluster of probes representing transcripts up-regulated by 1-MCP alone but down-regulated by ethylene alone or in the presence of 1-MCP support this suggestion. Ethylene and 1-MCP both down52 regulated a probe tentatively annotated as an ethylene receptor as well as EIN3, suggesting that both treatments down-regulate the perception and signalling events of ethylene
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