Length-scale-dependent phase transition in BSCCO single crystals

Electrical transport measurements using a multiterminal configuration are presented, which prove that in BSCCO single crystals near the transition temperature in zero external magnetic field the secondary voltage is induced by thermally activated vortex loop unbinding. The phase transition between the bound and unbound states of the vortex loops was found to be below the temperature where the phase coherence of the superconducting order parameter extends over the whole volume of the sample. We show experimentally that 3D/2D phase transition in vortex dimensionality is a length-scale-dependent layer decoupling process and takes place simultaneously with the 3D/2D phase transition in superconductivity at the same temperature.Comment: 14 pages, 4 figures, to be published in Philos. Ma

Exploring music with a probabilistic projection interface

We present the design and evaluation of an in- teractive tool for music exploration, with musi- cal mood and genre inferred directly from tracks. It uses probabilistic representations of multivari- able predictions of subjective characteristics of the music to give users subtle, nuanced visuali- sations of the 2D map. These explicitly repre- sent the uncertainty and overlap among features and support music exploration and casual playlist generation. A longitudinal trial in users’ homes showed that probabilistic highlighting of subjec- tive features led to more focused exploration in mouse activity logs, and 6 of 8 users preferred the probabilistic highlighting

Soaking up the oil: Biological impacts of dispersants and crude oil on the sponge Halichondria panicea

Used during an oil spill to minimise the formation of an oil slick, dispersants have negative biological effects on marine model organisms. However, no study has investigated the impacts of dispersants on adult sponge individuals. Here, we examine the effects of water accommodated oil fraction (WAF - oil in seawater), chemically enhanced WAF (CEWAF - oil and dispersant in seawater) and Benzo[A]Pyrene on sponge Halichondria panicea at physiological and molecular levels. Sponge clearance rate decreased sharply when exposed to WAF and CEWAF but the oil loading at which the clearance rate was reduced by 50% (ED50) was 39-fold lower in CEWAF than in WAF. Transcriptomic analysis revealed a homogenous molecular response with the greatest number of differentially expressed genes identified in CEWAF samples (1,461 genes). Specifically, genes involved in stress responses were up-regulated. This study presents evidence that the use of dispersants should be considered carefully in areas where sponges are present

Potential and current distribution in strongly anisotropic Bi(2)Sr(2) CaCu(2)O(8) single crystals at current breakdown

Experiments on potential differences in the low-temperature vortex solid phase of monocrystalline platelets of superconducting Bi(2)Sr(2)CaCu(2)O(8) (BSCCO) subjected to currents driven either through an "ab" surface or from one such surface to another show evidence of a resistive/nonresistive front moving progressively out from the current contacts as the current increases. The depth of the resistive region has been measured by a novel in-depth voltage probe contact. The position of the front associated with an injection point appears to depend only on the current magnitude and not on its withdrawal point. It is argued that enhanced nonresistive superconducting anisotropy limits current penetration to less than the London length and results in a flat rectangular resistive region with simultaneous "ab" and "c" current breakdown which moves progressively out from the injection point with increasing current. Measurements in "ab" or "c" configurations are seen to give the same information, involving both ab-plane and c-axis conduction properties.Comment: 9 pages, 13 figures, typo error corrected, last section was refine

Benthic foraminiferal assemblages and test accumulation in coastal microhabitats on San Salvador, Bahamas

Benthic foraminiferal populations were studied in a shallow bay of San Salvador Island, the Bahamas. Surface sediments and marine macrophytes were collected from 14 sample sites along a 500&thinsp;m transect at Grahams Harbour to investigate the foraminiferal assemblage in each microhabitat and to test the link between dead foraminiferal test accumulation patterns and living epiphytic and sedimentary foraminiferal assemblages, macrophyte distribution, and environmental gradients. The analyses include grain size measurements, macrophyte biomass quantification, and qualitative and quantitative studies of benthic foraminifera. The foraminifera found attached to macrophytes differed between macrophyte habitats. However, a correlation between these living communities and the dead assemblages in the sediments at the same sites could not be observed. Principal component analysis (PCA) and redundancy analysis (RDA) suggest that the presence of the macroalgae Halimeda explains 16&thinsp;% of the residual faunal variation in the dead foraminiferal assemblage after the effects of sorting according to fall speed are partialled out. The RDA also reflects a positive correlation between foraminifera larger than 1.0&thinsp;mm in diameter and the 0.25–0.5&thinsp;mm sediment grain size, indicating sedimentological processes as the main factor controlling the sedimentary epiphytic foraminiferal assemblages. These sedimentary processes overprint most effects of ecological features or macrophyte-specific association.</p