An evaluation of the environmental and health effects of vehicle exhaust catalysts in the UK.

Since 1993, all new gasoline-engine automobiles in the United Kingdom have been supplied with three-way vehicle exhaust catalytic converters (VECs) containing platinum, palladium, and rhodium, to comply with European Commission Stage I limits on emissions of regulated pollutants: carbon monoxide, hydrocarbons, and oxides of nitrogen. We conducted a physical and economic evaluation of the environmental and health benefits from a reduction in emissions through this mandated environmental technology against the costs, with reference to urban areas in Great Britain. We made both an ex post assessment--based on available data to 1998--and an ex ante assessment--projected to 2005, the year when full penetration of VECs into the fleet is expected. Substantial health benefits in excess of the costs of VECs were indicated: By 1998 the estimated net societal health benefits were approximately 500 million British pounds, and by 2005 they were estimated to rise to as much as 2 billion British pounds. We also found through environmental surveys that although lead in road dust has fallen by 50% in urban areas, platinum accumulations near roads have risen significantly, up to 90-fold higher than natural background levels. This rapid accumulation of platinum suggests further monitoring is warranted, although as yet there is no evidence of adverse health effects

Stick or twist? Career decision-making during contractual uncertainty for NHS junior doctors

OBJECTIVES: To examine the extent, and nature, of impact on junior doctors' career decisions, of a proposed new contract and the uncertainty surrounding it. DESIGN: Mixed methods. Online survey exploring: doctors' future training intentions; their preferred specialty training (ST) programmes; whether they intended to proceed immediately to ST; and other plans. Linked qualitative interviews to explore more fully how and why decisions were affected. SETTING: Doctors (F2s) in second year of Foundation School (FS) Programmes in England. PARTICIPANTS: Invitations sent by FSs. Open to all F2s November 2015-February 2016. All FSs represented. Survey completed by 816 F2s. Sample characteristics broadly similar to national F2 cohort. MAIN OUTCOME MEASURES: Proportions of doctors intending to proceed to ST posts in the UK, to defer or to exit UK medicine. Proportion of doctors indicating changes in training and career plans as a result of the contract and/or resulting uncertainty. Distribution of changes across training programmes. Explanations of these intentions from interviews and free text comments. RESULTS: Among the responding junior doctors, 20% indicated that issues related to the contract had prompted them to switch specialty and a further 20% had become uncertain about switching specialty. Switching specialty choice was more prevalent among those now choosing a community-based, rather than hospital-based specialty. 30% selecting general practice had switched choice because of the new contract. Interview data suggests that doctors felt they had become less valued or appreciated in the National Health Service and in society more broadly. CONCLUSIONS: Doctors reported that contract-related issues have affected their career plans. The most notable effect is a move away from acute to community-based specialities, with the former perceived as more negatively affected by the proposed changes. It is concerning that young doctors feel undervalued, and this requires further investigation

Cerebellar-inspired algorithm for adaptive control of nonlinear dielectric elastomerbased artificial muscle

© 2016 The Author(s) Published by the Royal Society. All rights reserved. Electroactive polymer actuators are important for soft robotics, but can be difficult to control because of compliance, creep and nonlinearities. Because biological control mechanisms have evolved to deal with such problems, we investigated whether a control scheme based on the cerebellum would be useful for controlling a nonlinear dielectric elastomer actuator, a class of artificial muscle. The cerebellum was represented by the adaptive filter model, and acted in parallel with a brainstem, an approximate inverse plant model. The recurrent connections between the two allowed for direct use of sensory error to adjust motor commands. Accurate tracking of a displacement command in the actuator's nonlinear range was achieved by either semi-linear basis functions in the cerebellar model or semi-linear functions in the brainstem corresponding to recruitment in biological muscle. In addition, allowing transfer of training between cerebellum and brainstem as has been observed in the vestibulo-ocular reflex prevented the steady increase in cerebellar output otherwise required to deal with creep. The extensibility and relative simplicity of the cerebellar-based adaptive-inverse control scheme suggests that it is a plausible candidate for controlling this type of actuator. Moreover, its performance highlights important features of biological control, particularly nonlinear basis functions, recruitment and transfer of training

Visual-tactile sensory map calibration of a biomimetic whiskered robot

© 2016 IEEE. We present an adaptive filter model of cerebellar function applied to the calibration of a tactile sensory map to improve the accuracy of directed movements of a robotic manipulator. This is demonstrated using a platform called Bellabot that incorporates an array of biomimetic tactile whiskers, actuated using electro-active polymer artificial muscles, a camera to provide visual error feedback, and a standard industrial robotic manipulator. The algorithm learns to accommodate imperfections in the sensory map that may be as a result of poor manufacturing tolerances or damage to the sensory array. Such an ability is an important pre-requisite for robust tactile robotic systems operating in the real-world for extended periods of time. In this work the sensory maps have been purposely distorted in order to evaluate the performance of the algorithm

Development of a regional glycerol dialkyl glycerol tetraether (GDGT)-temperature calibration for Antarctic and sub-Antarctic lakes

A regional network of quantitative reconstructions of past climate variability is required to test climate models. In recent studies, temperature calibration models based on the relative abundances of sedimentary glycerol dialkyl glycerol tetraethers (GDGTs) have enabled past temperature reconstructions in both marine and terrestrial environments. Nevertheless, to date these methods have not been widely applied in high latitude environments due to poor performance of the GDGT–temperature calibrations at lower temperatures. To address this we studied 32 lakes from Antarctica, the sub-Antarctic Islands and Southern Chile to: 1) quantify their GDGT composition and investigate the environmental controls on GDGT composition; and 2) develop a GDGT–temperature calibration model for inferring past temperatures from Antarctic and sub-Antarctic lakes. GDGTs were found in all 32 lakes studied and in 31 lakes branched GDGTs (brGDGTs) were the dominant compounds. Statistical analyses of brGDGT composition in relation to temperature, pH, conductivity and water depth showed that the composition of brGDGTs is strongly correlated with mean summer air temperature (MSAT). This enabled the development of the first regional brGDGT–temperature calibration for use in Antarctic and sub-Antarctic lakes using four brGDGT compounds (GDGT-Ib, GDGT-II, GDGT-III and GDGT-IIIb). A key discovery was that GDGT-IIIb is of particular importance in cold lacustrine environments. The addition of this compound significantly improved the model's performance from r2=0.67r2=0.67, RMSEP-LOO (leave-one-out) = 2.23 °C, RMSEP-H (h-block) = 2.37 °C when applying the re-calibrated global GDGT–temperature calibration to our Antarctic dataset to r2=0.83r2=0.83, RMSEP-LOO = 1.68 °C, RMSEP-H = 1.65 °C for our new Antarctic calibration. This shows that Antarctic and sub-Antarctic, and possibly other high latitude, palaeotemperature reconstructions should be based on a regional GDGT–temperature calibration where specific compounds can be identified and included to improve model performance. Finally, downcore temperature reconstructions using the new Antarctic brGDGT–temperature calibration were tested in sub-Antarctic Fan Lake from South Georgia providing a proof of concept for the new calibration model in the Southern Hemisphere

Low dose influenza virus challenge in the ferret leads to increased virus shedding and greater sensitivity to oseltamivir

Ferrets are widely used to study human influenza virus infection. Their airway physiology and cell receptor distribution makes them ideal for the analysis of pathogenesis and virus transmission, and for testing the efficacy of anti-influenza interventions and vaccines. The 2009 pandemic influenza virus (H1N1pdm09) induces mild to moderate respiratory disease in infected ferrets, following inoculation with 106 plaque-forming units (pfu) of virus. We have demonstrated that reducing the challenge dose to 102 pfu delays the onset of clinical signs by 1 day, and results in a modest reduction in clinical signs, and a less rapid nasal cavity innate immune response. There was also a delay in virus production in the upper respiratory tract, this was up to 9-fold greater and virus shedding was prolonged. Progression of infection to the lower respiratory tract was not noticeably delayed by the reduction in virus challenge. A dose of 104 pfu gave an infection that was intermediate between those of the 106 pfu and 102 pfu doses. To address the hypothesis that using a more authentic low challenge dose would facilitate a more sensitive model for antiviral efficacy, we used the well-known neuraminidase inhibitor, oseltamivir. Oseltamivir-treated and untreated ferrets were challenged with high (106 pfu) and low (102 pfu) doses of influenza H1N1pdm09 virus. The low dose treated ferrets showed significant delays in innate immune response and virus shedding, delayed onset of pathological changes in the nasal cavity, and reduced pathological changes and viral RNA load in the lung, relative to untreated ferrets. Importantly, these observations were not seen in treated animals when the high dose challenge was used. In summary, low dose challenge gives a disease that more closely parallels the disease parameters of human influenza infection, and provides an improved pre-clinical model for the assessment of influenza therapeutics, and potentially, influenza vaccines

Biohybrid control of general linear systems using the adaptive filter model of cerebellum

© 2015 Wilson, Assaf, Pearson, Rossiter, Dean, Anderson and Porrill. The adaptive filter model of the cerebellar microcircuit has been successfully applied to biological motor control problems, such as the vestibulo-ocular reflex (VOR), and to sensory processing problems, such as the adaptive cancelation of reafferent noise. It has also been successfully applied to problems in robotics, such as adaptive camera stabilization and sensor noise cancelation. In previous applications to inverse control problems, the algorithm was applied to the velocity control of a plant dominated by viscous and elastic elements. Naive application of the adaptive filter model to the displacement (as opposed to velocity) control of this plant results in unstable learning and control. To be more generally useful in engineering problems, it is essential to remove this restriction to enable the stable control of plants of any order. We address this problem here by developing a biohybrid model reference adaptive control (MRAC) scheme, which stabilizes the control algorithm for strictly proper plants. We evaluate the performance of this novel cerebellar-inspired algorithm with MRAC scheme in the experimental control of a dielectric electroactive polymer, a class of artificial muscle. The results show that the augmented cerebellar algorithm is able to accurately control the displacement response of the artificial muscle. The proposed solution not only greatly extends the practical applicability of the cerebellar-inspired algorithm, but may also shed light on cerebellar involvement in a wider range of biological control tasks