First year student experience

The application was made on behalf of the undergraduate courses team who sought to enhance the first year experience by engaging students in the practice of business. The intention was to develop and signpost enterprising qualities and characteristics in first year learners and develop confidence as well as competence. The undergraduate review for FBL commenced in September 2009. This offered an opportunity to innovate and build good practice in enterprise learning as a pilot to inform the undergraduate review. The team sought to provide a coherent and relevant set of learning experiences that could be achieved outside structured curriculum that would enable learning through live projects

Screening effects in the electron-optical phonon interaction

We show that recently reported unusual hardening of optical phonons renormalized by the electron-phonon interaction is due to the neglect of screening effects. When the electron-ion interaction is properly screened optical phonons soften in three dimension. It is important that for short-wavelength optical phonons screening is static while for long-wavelength optical phonons screening is dynamic. In two-dimensional and one-dimensional cases due to crossing of the nonperturbed optical mode with gapless plasmons the spectrum of renormalized optical phonon-plasmon mode shows split momentum dependence.Comment: 7 page

Site of action of a halogenated 4-hydroxypyridine on ferredoxin-catalysed cyclic photophosphorylation

AbstractTetrabromo-4-hydroxypyridine (J820) inhibited ferredoxin-catalysed cyclic photophosphorylation at micromolar concentrations but did not inhibit or uncouple the AQS-catalysed system. At 2 μM it did not abolish the slow phase of the electrochromic shift or affect the turnover of cytochromes b-563 and f. At higher concentrations (10 μM) it decreased the rate of re-reduction of cytochrome f, whilst inhibiting the reduction of cytochrome b-563. It is concluded that tetrabromo-4-hydroxpyridine does not bind to the quinone reduction site of the cytochrome bf complex, but inhibits the putative ferredoxin-plastoquinone reductase

Sub-linear radiation power dependence of photo-excited resistance oscillations in two-dimensional electron systems

We find that the amplitude of the $R_{xx}$ radiation-induced magnetoresistance oscillations in GaAs/AlGaAs system grows nonlinearly as $A \propto P^{\alpha}$ where $A$ is the amplitude and the exponent $\alpha < 1$. %, with $\alpha \rightarrow 1/2$ in %the low temperature limit. This striking result can be explained with the radiation-driven electron orbits model, which suggests that the amplitude of resistance oscillations depends linearly on the radiation electric field, and therefore on the square root of the power, $P$. We also study how this sub-linear power law varies with lattice temperature and radiation frequency.Comment: 5 pages, 3 figure

Retrospective Cost Optimization for Adaptive State Estimation, Input Estimation, and Model Refinement

AbstractRetrospective cost optimization was originally developed for adaptive control. In this paper, we show how this technique is applicable to three distinct but related problems, namely, state estimation, input estimation, and model refinement. To illustrate these techniques, we give two examples. In the first example, retrospective cost model refinement is used with synthetic data to estimate the cooling dynamics that are missing from a model of the ionosphere-thermosphere. In the second example, retrospective cost adaptive state estimation is used with data from a satellite to estimate a solar driver in the ionosphere- thermosphere, with performance gauged by using data from a second satellite

Introductory Editorial: Evolutionary Genomics

This supplement is intended to focus on evolutionary genomics. Evolutionary Bioinformatics aims to provide researchers working in this complex, quickly developing field with online, open access to highly relevant scholarly articles by leading international researchers. In a field where the literature is ever-expanding, researchers increasingly need access to up-to-date, high quality scholarly articles on areas of specific contemporary interest. This supplement aims to address this by presenting high-quality articles that allow readers to distinguish the signal from the noise. The editor in chief hopes that through this effort, practitioners and researchers will be aided in finding answers to some of the most complex and pressing issues of our time

A dynamical mechanism for the origin of nuclear rings

We develop a dynamical theory for the origin of nuclear rings in barred galaxies. In analogy with the standard theory of accretion discs, our theory is based on shear viscous forces among nested annuli of gas. However, the fact that gas follows non circular orbits in an external barred potential has profound consequences: it creates a region of reverse shear in which it is energetically favourable to form a stable ring which does not spread despite dissipation. Our theory allows us to approximately predict the size of the ring given the underlying gravitational potential. The size of the ring is loosely related to the location of the Inner Lindblad Resonance in the epicyclic approximation, but the predicted location is more accurate and is also valid for strongly barred potentials. By comparing analytical predictions with the results of hydrodynamical simulations, we find that our theory provides a viable mechanism for ring formation if the effective sound speed of the gas is low (\cs\lesssim1\kms), but that nuclear spirals/shocks created by pressure destroy the ring when the sound speed is high (\cs\simeq10\kms). We conclude that whether this mechanism for ring formation is relevant for real galaxies ultimately depends on the effective equation of state of the ISM. Promising confirmation comes from simulations in which the ISM is modelled using state-of-the-art cooling functions coupled to live chemical networks, but more tests are needed regarding the role of turbulence driven by stellar feedback. If the mechanism is relevant in real galaxies, it could provide a powerful tool to constrain the gravitational potential, in particular the bar pattern speed.Comment: Accepted for publication in MNRA

Minimum Thermal Conductivity of Superlattices

The phonon thermal conductivity of a multilayer is calculated for transport perpendicular to the layers. There is a cross over between particle transport for thick layers to wave transport for thin layers. The calculations shows that the conductivity has a minimum value for a layer thickness somewhat smaller then the mean free path of the phonons.Comment: new results added, to appear in PR