Elastic precursor of the transformation from glycolipid-nanotube to -vesicle

By the combination of optical tweezer manipulation and digital video microscopy, the flexural rigidity of single glycolipid "nano" tubes has been measured below the transition temperature at which the lipid tubules are transformed into vesicles. Consequently, we have found a clear reduction of the rigidity obviously before the transition as temperature increasing. Further experiments of infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) have suggested a microscopic change of the tube walls, synchronizing with the precursory softening of the nanotubes.Comment: 9 pages, 6 figure

Cassiopeia A: dust factory revealed via submillimetre polarimetry

If Type-II supernovae - the evolutionary end points of short-lived, massive stars - produce a significant quantity of dust (>0.1 M_sun) then they can explain the rest-frame far-infrared emission seen in galaxies and quasars in the first Gyr of the Universe. Submillimetre observations of the Galactic supernova remnant, Cas A, provided the first observational evidence for the formation of significant quantities of dust in Type-II supernovae. In this paper we present new data which show that the submm emission from Cas A is polarised at a level significantly higher than that of its synchrotron emission. The orientation is consistent with that of the magnetic field in Cas A, implying that the polarised submm emission is associated with the remnant. No known mechanism would vary the synchrotron polarisation in this way and so we attribute the excess polarised submm flux to cold dust within the remnant, providing fresh evidence that cosmic dust can form rapidly. This is supported by the presence of both polarised and unpolarised dust emission in the north of the remnant, where there is no contamination from foreground molecular clouds. The inferred dust polarisation fraction is unprecedented (f_pol ~ 30%) which, coupled with the brief timescale available for grain alignment (<300 yr), suggests that supernova dust differs from that seen in other Galactic sources (where f_pol=2-7%), or that a highly efficient grain alignment process must operate in the environment of a supernova remnant.Comment: In press at MNRAS, 10 pages, print in colou

Combining high conductivity with complete optical transparency: A band-structure approach

A comparison of the structural, optical and electronic properties of the recently discovered transparent conducting oxide (TCO), nanoporous Ca12Al14O33, with those of the conventional TCO's (such as Sc-doped CdO) indicates that this material belongs conceptually to a new class of transparent conductors. For this class of materials, we formulate criteria for the successful combination of high electrical conductivity with complete transparency in the visible range. Our analysis suggests that this set of requirements can be met for a group of novel materials called electrides.Comment: 3 pages, 3 figures, submitted for publicatio

On Invariant Notions of Segre Varieties in Binary Projective Spaces

Invariant notions of a class of Segre varieties \Segrem(2) of PG(2^m - 1, 2) that are direct products of $m$ copies of PG(1, 2), $m$ being any positive integer, are established and studied. We first demonstrate that there exists a hyperbolic quadric that contains \Segrem(2) and is invariant under its projective stabiliser group \Stab{m}{2}. By embedding PG(2^m - 1, 2) into \PG(2^m - 1, 4), a basis of the latter space is constructed that is invariant under \Stab{m}{2} as well. Such a basis can be split into two subsets whose spans are either real or complex-conjugate subspaces according as $m$ is even or odd. In the latter case, these spans can, in addition, be viewed as indicator sets of a \Stab{m}{2}-invariant geometric spread of lines of PG(2^m - 1, 2). This spread is also related with a \Stab{m}{2}-invariant non-singular Hermitian variety. The case $m=3$ is examined in detail to illustrate the theory. Here, the lines of the invariant spread are found to fall into four distinct orbits under \Stab{3}{2}, while the points of PG(7, 2) form five orbits.Comment: 18 pages, 1 figure; v2 - version accepted in Designs, Codes and Cryptograph

Sea temperature effects on depth use and habitat selection in a marine fish community

Understanding the responses of aquatic animals to temperature variability is essential to predict impacts of future climate change and to inform conservation and management. Most ectotherms such as fish are expected to adjust their behaviour to avoid extreme temperatures and minimize acute changes in body temperature. In coastal Skagerrak, Norway, sea surface temperature (SST) ranges seasonally from 0 to over 20°C, representing a challenge to the fish community which includes cold-, cool- and warm-water affinity species.publishedVersio

Nanomechanics of microtubules

We have determined the mechanical anisotropy of a single microtubule by simultaneously measuring the Young's and the shear moduli in vitro. This was achieved by elastically deforming the microtubule deposited on a substrate tailored by electron-beam lithography with a tip of an atomic force microscope. The shear modulus is 2 orders of magnitude lower than the Young's, giving rise to a length-dependent flexural rigidity of microtubules. The temperature dependence of the microtubule's bending stiffness in the (5-40) degreesC range shows a strong variation upon cooling coming from the increasing interaction between the protofilaments

A review of climate change and the implementation of marine biodiversity legislation in the United Kingdom

1. Marine legislation, the key means by which the conservation of marine biodiversity is achieved, has been developing since the 1960s. In recent decades, an increasing focus on ‘holistic’ policy development is evident, compared with earlier ‘piecemeal’ sectoral approaches. Important marine legislative tools being used in the United Kingdom, and internationally, include the designation of marine protected areas and the Marine Strategy Framework Directive (MSFD) with its aim of meeting ‘Good Environmental Status’ (GES) for European seas by 2020. 2. There is growing evidence of climate change impacts on marine biodiversity, which may compromise the effectiveness of any legislation intended to promote sustainable marine resource management. 3. A review of key marine biodiversity legislation relevant to the UK shows climate change was not considered in the drafting of much early legislation. Despite the huge increase in knowledge of climate change impacts in recent decades, legislation is still limited in how it takes these impacts into account. There is scope, however, to account for climate change in implementing much of the legislation through (a) existing references to environmental variability; (b) review cycles; and (c) secondary legislation and complementary policy development. 4. For legislation relating to marine protected areas (e.g. the EC Habitats and Birds Directives), climate change has generally not been considered in the site-designation process, or for ongoing management, with the exception of the Marine (Scotland) Act. Given that changing environmental conditions (e.g. rising temperatures and ocean acidification) directly affect the habitats and species that sites are designated for, how this legislation is used to protect marine biodiversity in a changing climate requires further consideration. 5. Accounting for climate change impacts on marine biodiversity in the development and implementation of legislation is vital to enable timely, adaptive management responses. Marine modelling can play an important role in informing management decisions