Asymptotic Giant Branch Variables in the Galaxy and the Local Group

AGB variables, particularly the large amplitude Mira type, are a vital step on the distance scale ladder. They will prove particularly important in the era of space telescopes and extremely large ground-based telescopes with adaptive optics, which will be optimized for infrared observing. Our current understanding of the distances to these stars is reviewed with particular emphasis on improvements that came from Hipparcos as well as on recent work on Local Group galaxies. In addition to providing the essential calibration for extragalactic distances Gaia may also provide unprecedented insight into the poorly understood mass-loss process itself.Comment: Accepted for publication in Astrophysics and Space Science. From a presentation at the conference "The Fundamental Cosmic Distance Scale: State of the Art and Gaia Perspective, Naples May 2011. 8 Pages, 9 Figure

Diamond like carbon coatings for potential application in biological implants – a review

Production of wear debris has been linked to the failure of numerous hip implants. With the current focus on increasing the implant longevity, thus wear and corrosion resistance is important. Hard coatings have the potential to reduce the wear and corrosion. Diamond like Carbon (DLC) coatings exhibit properties that could make them viable for implants. This paper critically reviews previously published research into usage of DLC coatings for implants. Overall DLCs seem to be an effective coating for implants but with the variance in results, further testing is required for clarification of us

Sub-wavelength diffraction-free imaging with low-loss metal-dielectric multilayers

We demonstrate numerically the diffraction-free propagation of sub-wavelength sized optical beams through simple elements built of metal-dielectric multilayers. The proposed metamaterial consists of silver and a high refractive index dielectric, and is designed using the effective medium theory as strongly anisotropic and impedance matched to air. Further it is characterised with the transfer matrix method, and investigated with FDTD. The diffraction-free behaviour is verified by the analysis of FWHM of PSF in the function of the number of periods. Small reflections, small attenuation, and reduced Fabry Perot resonances make it a flexible diffraction-free material for arbitrarily shaped optical planar elements with sizes of the order of one wavelength.Comment: 5 pages, 4 figure

A learning development team: three developers, one pedagogy

With the inception of Centres for Excellence in Teaching and Learning (CETLs), the demand for learning developers has increased in many institutions across the UK. Operating largely in small teams, yet within the remit of facilitating large-scale institutional change, CETLs often find themselves outside established institutional structures, with developers fulfilling newly defined roles and responsibilities. This short paper focuses on the way learning development support has been integrated in one particular CETL, in order to explore issues, challenges and experiences that are part of the role

Inquiry based assessment of statistical methods in psychology

This book is essential reading for anyone involved in teaching statistics at tertiary level or interested in statistical education research

Metal-rich carbon stars in the Sagittarius dwarf spheroidal galaxy

‘The definitive version is available at: www3.interscience.wiley.com '. Copyright Blackwell / Royal Astronomical Society. DOI: 10.1111/j.1365-2966.2009.14736.xWe present spectroscopic observations from the Spitzer Space Telescope of six carbon-rich asymptotic giant branch (AGB) stars in the Sagittarius dwarf spheroidal galaxy (Sgr dSph) and two foreground Galactic carbon stars. The band strengths of the observed C2H2 and SiC features are very similar to those observed in Galactic AGB stars. The metallicities are estimated from an empirical relation between the acetylene optical depth and the strength of the SiC feature. The metallicities are higher than those of the Large Magellanic Cloud, and close to Galactic values. While the high metallicity could imply an age of around 1 Gyr, for the dusty AGB stars, the pulsation periods suggest ages in excess of 2 or 3 Gyr. We fit the spectra of the observed stars using the dusty radiative transfer model and determine their dust mass-loss rates to be in the range 1.0–3.3 × 10−8 M⊙ yr−1 . The two Galactic foreground carbon-rich AGB stars are located at the far side of the solar circle, beyond the Galactic Centre. One of these two stars shows the strongest SiC feature in our present Local Group sample.Peer reviewe

Analysis of travelling waves associated with the modelling of aerosolised skin grafts

A previous model developed by the authors investigates the growth patterns of keratinocyte cell colonies after they have been applied to a burn site using a spray technique. In this paper, we investigate a simplified one-dimensional version of the model. This model yields travelling wave solutions and we analyse the behaviour of the travelling waves. Approximations for the rate of healing and maximum values for both the active healing and the healed cell densities are obtained

Targeted classification of metal–organic frameworks in the Cambridge structural database (CSD)

Large-scale targeted exploration of metal–organic frameworks (MOFs) with characteristics such as specific surface chemistry or metal-cluster family has not been investigated so far. These definitions are particularly important because they can define the way MOFs interact with specific molecules (e.g. their hydrophilic/phobic character) or their physicochemical stability. We report here the development of algorithms to break down the overarching family of MOFs into a number of subgroups according to some of their key chemical and physical features. Available within the Cambridge Crystallographic Data Centre's (CCDC) software, we introduce new approaches to allow researchers to browse and efficiently look for targeted MOF families based on some of the most well-known secondary building units. We then classify them in terms of their crystalline properties: metal-cluster, network and pore dimensionality, surface chemistry (i.e. functional groups) and chirality. This dynamic database and family of algorithms allow experimentalists and computational users to benefit from the developed criteria to look for specific classes of MOFs but also enable users – and encourage them – to develop additional MOF queries based on desired chemistries. These tools are backed-up by an interactive web-based data explorer containing all the data obtained. We also demonstrate the usefulness of these tools with a high-throughput screening for hydrogen storage at room temperature. This toolbox, integrated in the CCDC software, will guide future exploration of MOFs and similar materials, as well as their design and development for an ever-increasing range of potential applications