OER Evidence Report 2013-2014

The Open Educational Resources Research Hub (OER Research Hub) provides a focus for research, designed to give answers to the overall question ‘What is the impact of OER on learning and teaching practices?’ and identify the particular influence of openness. We do this by working in collaboration with projects across four education sectors (K12, college, higher education and informal) extending a network of research with shared methods and shared results. The project combines: – Targeted research collaboration with high profile OER projects – A programme of international fellowship – Global networking and expertise in OER implementation and evaluation – A hub for research data and excellence in practice This report is an interim review of evidence recorded against the key hypotheses that focus the research of the OER Research Hub project

Theoretical modeling of two-color coherent anti-Stokes Raman spectroscopy spectra measured with a frequency-doubled, multimode pump laser

We have theoretically modeled coherent anti-Stokes Raman spectroscopy spectra of nitrogen measured with a frequency-doubled Nd:YAG pump laser. The fluctuations of the multimode pump field are modeled using a field variable having non-Gaussian statistics derived from a functional dependence on a Gaussian field. Both isolated and multiple, overlapping transitions are treated. The model qualitatively predicts the non-Gaussian effects observed in experiments but somewhat overemphasizes the magnitude of these features

Atomistic Molecular Dynamics Simulations of Shock Compressed Quartz

Atomistic non-equilibrium molecular dynamics (NEMD) simulations of shock wave compression of quartz have been performed using the so-called BKS semi-empirical potential of van Beest, Kramer and van Santen to construct the Hugoniot of quartz. Our scheme mimics the real world experimental set up by using a flyer-plate impactor to initiate the shock wave and is the first shock wave simulation that uses a geom- etry optimised system of a polar slab in a 3-dimensional system employing periodic boundary conditions. Our scheme also includes the relaxation of the surface dipole in the polar quartz slab which is an essential pre-requisite to a stable simulation. The original BKS potential is unsuited to shock wave calculations and so we propose a simple modification. With this modification, we find that our calculated Hugoniot is in good agreement with experimental shock wave data up to 25 GPa, but significantly diverges beyond this point. We conclude that our modified BKS potential is suitable for quartz under representative pressure conditions of the Earth core, but unsuitable for high-pressure shock wave simulations. We also find that the BKS potential incorrectly prefers the {\beta}-quartz phase over the {\alpha}-quartz phase at zero-temperature, and that there is a {\beta} \rightarrow {\alpha} phase-transition at 6 GPa.Comment: 19 pages, 13 figures, Accepted for publication in Journal of Chemical Physic

Bayes linear kinematics in the analysis of failure rates and failure time distributions

Collections of related Poisson or binomial counts arise, for example, from a number of different failures in similar machines or neighbouring time periods. A conventional Bayesian analysis requires a rather indirect prior specification and intensive numerical methods for posterior evaluations. An alternative approach using Bayes linear kinematics in which simple conjugate specifications for individual counts are linked through a Bayes linear belief structure is presented. Intensive numerical methods are not required. The use of transformations of the binomial and Poisson parameters is proposed. The approach is illustrated in two examples, one involving a Poisson count of failures, the other involving a binomial count in an analysis of failure times

Evaluation of elicitation methods to quantify Bayes linear models

The Bayes linear methodology allows decision makers to express their subjective beliefs and adjust these beliefs as observations are made. It is similar in spirit to probabilistic Bayesian approaches, but differs as it uses expectation as its primitive. While substantial work has been carried out in Bayes linear analysis, both in terms of theory development and application, there is little published material on the elicitation of structured expert judgement to quantify models. This paper investigates different methods that could be used by analysts when creating an elicitation process. The theoretical underpinnings of the elicitation methods developed are explored and an evaluation of their use is presented. This work was motivated by, and is a precursor to, an industrial application of Bayes linear modelling of the reliability of defence systems. An illustrative example demonstrates how the methods can be used in practice

The impact of COVID-19 on opioid use in those awaiting hip and knee arthroplasty : A retrospective cohort study

Peer reviewedPostprin

Reducing MCPA herbicide pollution at catchment scale using an agri-environmental scheme

Publication history: Accepted - 16 May 2022; Published online - 20 May 2022.In river catchments used as drinking water sources, high pesticide concentrations in abstracted waters require an expensive treatment step prior to supply. The acid herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) is particularly problematic as it is highly mobile in the soil-water environment following application. Here, an agri-environmental scheme (AES) was introduced to a large-scale catchment (384 km2) to potentially reduce the burden of pesticides in the water treatment process. The main measure offered was contractor application of glyphosate by weed wiping as a substitute for boom spraying of MCPA, supported by educational and advisory activities. A combined innovation applied in the assessment was, i) a full before-after-control-impact (BACI) framework over four peak application seasons (April to October 2018 to 2021) where a neighbouring catchment (386 km2) did not have an AES and, ii) an enhanced monitoring approach where river discharge and MCPA concentrations were measured synchronously in each catchment. During peak application periods the sample resolution was every 7 h, and daily during quiescent winter periods. This sampling approach enabled flow- and time-weighted concentrations to be established, and a detailed record of export loads. These loads were up to 0.242 kg km−2 yr−1, and over an order of magnitude higher than previously reported in the literature. Despite this, and accounting for inter-annual and seasonal variations in river discharges, the AES catchment indicated a reduction in both flow- and time-weighted MCPA concentration of up to 21% and 24%, respectively, compared to the control catchment. No pollution swapping was detected. Nevertheless, the percentage of MCPA occurrences above a 0.1 μg L−1 threshold did not reduce and so the need for treatment was not fully resolved. Although the work highlights the advantages of catchment management approaches for pollution reduction in source water catchments, it also indicates that maximising participation will be essential for future AES.This work was carried out as part of Source to Tap (IVA5018), a project supported by the European Union's INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPB)

Cross sections for ionization and excitation in the two-photon transitions of CO B-X(0,0)

High-resolution spectroscopy of CO B-X is being performed to measure cross sections for the processes of two-photon absorption and ionization that underlie two methods often used for sensitive detection of CO in flames, namely, two-photon LIF and 2+1 resonance-enhanced multiphoton ionization (REMPI) via B(v=0). The use of multiphoton excitation is, for even LIF diagnostics, a practical necessity since the allowed one-photon transitions from CO X(v=0) begin at 152 nm. Two 230-nm photons, however, promotes transitions within B{l_arrow}X(0,0); detection in LIF then proceeds by collecting blue to green fluorescence in the Angstrom bands (B{r_arrow}A). In 2+1 REMPI, the ions (or electrons) are monitored as produced by a third ionizing photon at 230 nm that connects B(v=0) to the continuum. The signals acquired with either technique depend on the two-photon excitation rate and also on the ionization rate - a gain in REMPI signal from increased ionization is a loss to LIF in the manner of quenching. The authors have found no direct measurement of the ionization cross section of CO-B in the literature, in that all reported cross sections are extracted from measured trends of REMPI or fluorescence signals versus laser. A rate-equation analysis of a multi-level system was the usual model, with cross sections for intensity, two-photon absorption and ionization varied for best match with the measured trends. Further, only one such study, that of Looney et al., has offered a cross section for the photo-ionization of CO-B at 230 nm