Commensurability oscillations due to pinned and drifting orbits in a two-dimensional lateral surface superlattice

We have simulated conduction in a two-dimensional electron gas subject to a weak two-dimensional periodic potential, $V_x \cos(2\pi x/a) + V_y \cos(2\pi y/a)$. The usual commensurability oscillations in $\rho_{xx}(B)$ are seen with $V_x$ alone. An increase of $V_y$ suppresses these oscillations, rather than introducing the additional oscillations in $\rho_{yy}(B)$ expected from previous perturbation theories. We show that this behavior arises from drift of the guiding center of cyclotron motion along contours of an effective potential. Periodic modulation in the magnetic field can be treated in the same way.Comment: 3 pages text, 4 eps figures, revte

Modelling and Refinement in CODA

This paper provides an overview of the CODA framework for modelling and refinement of component-based embedded systems. CODA is an extension of Event-B and UML-B and is supported by a plug-in for the Rodin toolset. CODA augments Event-B with constructs for component-based modelling including components, communications ports, port connectors, timed communications and timing triggers. Component behaviour is specified through a combination of UML-B state machines and Event-B. CODA communications and timing are given an Event-B semantics through translation rules. Refinement is based on Event-B refinement and allows layered construction of CODA models in a consistent way.Comment: In Proceedings Refine 2013, arXiv:1305.563

Weekly vitamin D₃ supplementation improves aerobic performance in combat sport athletes

Vitamin D3 supplementation can affect the strength and power of an athlete, however the effect on endurance performance remains unclear. Twenty-seven recreational male combat athletes with at least 12 months experience within combat sports were recruited (age: 24 ± 4 years, stature: 176 ± 6 cm, weight: 77 ± 14 kg). Participants completed baseline testing for blood haemoglobin and haematocrit, upper and lower body VO2peak and upper and lower body Wingate. Following testing participants were stratified to 50000IU (D1), 80000IU (D2) or 110000IU (D3) of vitamin D3 per week. They then completed a 6-week placebo period followed by a 6-week supplementation period. Retesting was carried out after the placebo and supplementation period. There was a significant effect for time for haemoglobin and haematocrit, upper and lower body VO2peak and upper body Wingate power (p<0.01) but no effect for dose of vitamin D given. Performance data was normalised to vitamin D intake and there was a moderate effect size between D1 and D2 for lower body VO2peak (d=0.6), upper body VO2peak (d=0.13) and upper body average power (d=0.75), with a large effect size between D1 and D2 for haemoglobin (d=1.19), haematocrit (d=0.93) and upper body peak power (d=0.95). There was a large effect size for D1 compared to D3 for all variables (d>0.8). Therefore, there is no additional benefit to increasing dose above 500000IU vitamin D per week. Given the endurance adaptations from vitamin D supplementation and the importance of endurance for combat performance, recreational combat athletes should supplement at 50000IU per week for six weeks

Kinetics of reduction of a Resazurin-based photocatalytic activity ink

The kinetics of reduction of a Resazurin, Rz,-based photocatalyst activity indicator ink, paii, on a commercial sample of self-cleaning glass, Activ™ is examined; the latter has ca. a 15nm compact coating of anatase TiO2 which serves as the active photocatalyst layer. The rate of dye reduction is reduced significantly by the presence of ambient O2. In the absence of O2, the measured change in film absorbance due to Rz, d Δ Abs/dt, was found to be independent of both [Rz] and film thickness, b. It is shown that this translates to the rate of dye reduction, d[Rz]/dt, being independent of the concentration of the Rz in the ink film, [Rz], and inversely proportional to film thickness, b. The observed kinetics are rationalised in terms of a kinetic model in which the rate determining step is the reduction of photocatalyst surface-adsorbed Rz by photo-generated surface electrons, with all photocatalyst surface sites occupied by Rz. Further work suggests that, if the kinetics of the photocatalysed reduction of the Rz paii were diffusion-controlled, then the decay in [Rz] would be first order and dependent upon b-2

Quantifying methane and nitrous oxide emissions from the UK and Ireland using a national-scale monitoring network

The UK is one of several countries around the world that has enacted legislation to reduce its greenhouse gas emissions. In this study, we present top-down emissions of methane (CH4) and nitrous oxide (N2O) for the UK and Ireland over the period August 2012 to August 2014. These emissions were inferred using measurements from a network of four sites around the two countries. We used a hierarchical Bayesian inverse framework to infer fluxes as well as a set of covariance parameters that describe uncertainties in the system. We inferred average UK total emissions of 2.09 (1.65–2.67) Tg yr−1 CH4 and 0.101 (0.068–0.150) Tg yr−1 N2O and found our derived UK estimates to be generally lower than the a priori emissions, which consisted primarily of anthropogenic sources and with a smaller contribution from natural sources. We used sectoral distributions from the UK National Atmospheric Emissions Inventory (NAEI) to determine whether these discrepancies can be attributed to specific source sectors. Because of the distinct distributions of the two dominant CH4 emissions sectors in the UK, agriculture and waste, we found that the inventory may be overestimated in agricultural CH4 emissions. We found that annual mean N2O emissions were consistent with both the prior and the anthropogenic inventory but we derived a significant seasonal cycle in emissions. This seasonality is likely due to seasonality in fertilizer application and in environmental drivers such as temperature and rainfall, which are not reflected in the annual resolution inventory. Through the hierarchical Bayesian inverse framework, we quantified uncertainty covariance parameters and emphasized their importance for high-resolution emissions estimation. We inferred average model errors of approximately 20 and 0.4 ppb and correlation timescales of 1.0 (0.72–1.43) and 2.6 (1.9–20 3.9) days for CH4 and N2O, respectively. These errors are a combination of transport model errors as well as errors due to unresolved emissions processes in the inventory. We found the largest CH4 errors at the Tacolneston station in eastern England, which may be due to sporadic emissions from landfills and offshore gas in the North Sea

Weaber Plain aquifer test results

As a part of the environmental planning and approvals process, the state government was required to prepare Groundwater Management and Hydrodynamic Plans. These plans are to address potential issues of salinity and water quality that could result from the development of irrigated agriculture on the Weaber Plain. The Weaber Plain groundwater modelling report (KBR 2010a) identified several options to manage watertables and salinity Production bores 10WP35PB and 10WP36PB were drilled in the palaeochannel on sites selected from the interpretation of airborne geophysics

The social management of biomedical novelty : Facilitating translation in regenerative medicine

Regenerative medicine (RM) is championed as a potential source of curative treatments for a variety of illnesses, and as a generator of economic wealth and prosperity. Alongside this optimism, however, is a sense of concern that the translation of basic science into useful RM therapies will be laboriously slow due to a range of challenges relating to live tissue handling and manufacturing, regulation, reimbursement and commissioning, and clinical adoption. This paper explores the attempts of stakeholders to overcome these innovation challenges and thus facilitate the emergence of useful RM therapies. The paper uses the notion of innovation niches as an analytical frame. Innovation niches are collectively constructed socio-technical spaces in which a novel technology can be tested and further developed, with the intention of enabling wider adoption. Drawing on primary and secondary data, we explore the motivation for, and the attempted construction of, niches in three domains which are central to the adoption of innovative technologies: the regulatory, the health economic, and the clinical. We illustrate that these niches are collectively constructed via both formal and informal initiatives, and we argue that they reflect wider socio-political trends in the social management of biomedical novelty

Aligning technology and institutional readiness: the adoption of innovation

This paper explores and develops the concept of ‘readiness’ as it relates to the adoption of innovation. In particular, the paper discusses readiness in regard to the notion of ‘technology readiness’ levels, widely used today by both producers and users to monitor and manage emergent innovation. The paper argues that, while useful, this notion needs to be informed by and subsumed within a broader concept of ‘institutional readiness’. The latter is especially important in conceptualising how new technologies are actually adopted in organisational settings. The paper develops a model of institutional readiness that recognises the saliency of technology readiness but which embeds it within a broader sociotechnical framework. This is illustrated with reference to the emerging field of regenerative medici