The thermoelastic martensite transformation in copper-aluminium-nickel alloys

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'Bach's Organ Works': The Passacaglia and Fugue in C Minor

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A physical approach to modelling large-scale galactic magnetic fields

A convenient representation of the structure of the large-scale galactic magnetic field is required for the interpretation of polarization data in the sub-mm and radio ranges, in both the Milky Way and external galaxies. We develop a simple and flexible approach to construct parametrised models of the large-scale magnetic field of the Milky Way and other disc galaxies, based on physically justifiable models of magnetic field structure. The resulting models are designed to be optimised against available observational data. Representations for the large-scale magnetic fields in the flared disc and spherical halo of a disc galaxy were obtained in the form of series expansions whose coefficients can be calculated from observable or theoretically known galactic properties. The functional basis for the expansions is derived as eigenfunctions of the mean-field dynamo equation or of the vectorial magnetic diffusion equation. The solutions presented are axially symmetric but the approach can be extended straightforwardly to non-axisymmetric cases. The magnetic fields are solenoidal by construction, can be helical, and are parametrised in terms of observable properties of the host object, such as the rotation curve and the shape of the gaseous disc. The magnetic field in the disc can have a prescribed number of field reversals at any specified radii. Both the disc and halo magnetic fields can separately have either dipolar or quadrupolar symmetry. The model is implemented as a publicly available software package GalMag which allows, in particular, the computation of the synchrotron emission and Faraday rotation produced by the model's magnetic field. The model can be used in interpretations of observations of magnetic fields in the Milky Way and other spiral galaxies, in particular as a prior in Bayesian analyses. (Abridged.)Comment: 20 pages, 14 figures. Accepted for publication in A&

Potential for Forecasting UK Summer Grass Growth from the North Atlantic Oscillation

The North Atlantic Oscillation (NAO) is a large-scale atmospheric circulation pattern which is well-known to influence the UK winter climate (Wilby et al., 1997). Recently, it has been shown that the winter NAO also affects summer rainfall in the UK (Kettlewell et al., 2003). Since water supply is an important limitation to summer grass growth in many parts of the UK, the winter NAO may influence summer growth. The objective of this study was to test the hypothesis that there is a relationship between the winter NAO and summer grass growth using data from reference plots at North Wyke in Devon

Using trace element and halide isotopes to understand salinization mechanisms of groundwaters from an arid aquifer

Saline groundwaters are common to inland Australia, yet many aspects of their hydrochemical evolution remain uncertain. The saline groundwaters in the alluvial aquifers of the Darling River have previously been found to exhibit broad similarity in traditional hydrochemical and isotopic tracers. By contrast, trace element isotopes (δ7Li, δ11B and 87Sr/86Sr) and halide isotopes (δ37Cl and δ81Br) provide evidence of more complex hydrogeochemical processes.Hydrochemical evolution was found to be dependent on proximity to theDarling River and depth even though all groundwaters from this aquifer were found to be saline. The differing signatures highlighted the discovery of adeeper palaeo-groundwater system containing heavier trace element and halide isotope values. The measurement of these isotopes has permitted delineation of groundwater end-members and salinization mechanisms that would have otherwise not been identified

Distinct freshwater migratory pathways in Arctic char (Salvelinus alpinus) coincide with separate patterns of marine spatial habitat-use across a large coastal landscape

Understanding variability in distributions and habitat-use among populations of anadromous salmonids is essential for their sustainable management. Arctic char (Salvelinus alpinus) is an important cultural and socioeconomic species; however, knowledge of their spatiotemporal habitat-use during the marine phase is limited. Here, a large-scale acoustic telemetry array was used to determine intraspecific variation in Arctic char summer marine habitat-use tied to overwintering lake occurrence in the Amundsen Gulf. Arctic char tagged in the ocean migrated to two main overwintering lakes, corresponding to distinct migration corridors and separate patterns of marine habitat-use, with one individual exhibiting among the longest recorded char marine migration to date (∼330 km). Arctic char that undertook longer migration distances initiated travel in the ocean towards fresh water 11 days earlier than those completing shorter migration distances; mean departure days (±SD) 2 August (±8.1 days) and 13 August (±6.8 days), corresponding to migration distances of 252 and 131 km, respectively. These findings identify that Arctic char from different populations can occupy distinct marine foraging grounds within a region, with consequences for variable interactions with fisheries