996 research outputs found

    Developing modern multifunctional agroforestry systems for sustainable intensification

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    Agroforestry is a land-use system that integrates trees and shrubs with crops and/or livestock production. It has been identified by the International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD, 2008) as a ‘win-win’ approach that balances the production of commodities (food, feed, fuel, fibre, etc.) with non-commodity outputs such as environmental protection and cultural and landscape amenities. This paper will review the potential of agroforestry as part of a multifunctional working landscape in temperate regions, and will consider management and policy implications of widespread adoption of this form of land-use

    A participatory approach to variety trials for organic systems

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    A participatory research methodology was used to compare the performance of UK wheat varieties under organic conditions. Plots of three breadmaking winter wheat varieties (Hereward, Solstice and Xi19) and a mixture (1:1:1) of the varieties were grown at 19 UK farms in two seasons (2003/04 and 2004/05). Meas-urements were taken of growth habit, yield and grain quality. Grain yields in both seasons showed significant site by variety interactions, although the variation among sites was greater than among varieties in both instances. Wheat grown at Western sites was significantly shorter and higher-yielding than that grown at Eastern sites in 2003/04 but significantly taller in 2004/05. As with grain yield, greater variation among site than variety was found in the Hagberg Falling Number and protein concentra-tion results in both seasons. The results from the two years of trials illustrate the variability of organic systems and the difficulty in selecting a single variety suitable for organic farms

    Salience-based selection: attentional capture by distractors less salient than the target

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    Current accounts of attentional capture predict the most salient stimulus to be invariably selected first. However, existing salience and visual search models assume noise in the map computation or selection process. Consequently, they predict the first selection to be stochastically dependent on salience, implying that attention could even be captured first by the second most salient (instead of the most salient) stimulus in the field. Yet, capture by less salient distractors has not been reported and salience-based selection accounts claim that the distractor has to be more salient in order to capture attention. We tested this prediction using an empirical and modeling approach of the visual search distractor paradigm. For the empirical part, we manipulated salience of target and distractor parametrically and measured reaction time interference when a distractor was present compared to absent. Reaction time interference was strongly correlated with distractor salience relative to the target. Moreover, even distractors less salient than the target captured attention, as measured by reaction time interference and oculomotor capture. In the modeling part, we simulated first selection in the distractor paradigm using behavioral measures of salience and considering the time course of selection including noise. We were able to replicate the result pattern we obtained in the empirical part. We conclude that each salience value follows a specific selection time distribution and attentional capture occurs when the selection time distributions of target and distractor overlap. Hence, selection is stochastic in nature and attentional capture occurs with a certain probability depending on relative salience

    Modelling search for people in 900 scenes: A combined source model of eye guidance

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    How predictable are human eye movements during search in real world scenes? We recorded 14 observers’ eye movements as they performed a search task (person detection) in 912 outdoor scenes. Observers were highly consistent in the regions fixated during search, even when the target was absent from the scene. These eye movements were used to evaluate computational models of search guidance from three sources: Saliency, target features, and scene context. Each of these models independently outperformed a cross-image control in predicting human fixations. Models that combined sources of guidance ultimately predicted 94% of human agreement, with the scene context component providing the most explanatory power. None of the models, however, could reach the precision and fidelity of an attentional map defined by human fixations. This work puts forth a benchmark for computational models of search in real world scenes. Further improvements in modelling should capture mechanisms underlying the selectivity of observers’ fixations during search.National Eye Institute (Integrative Training Program in Vision grant T32 EY013935)Massachusetts Institute of Technology (Singleton Graduate Research Fellowship)National Science Foundation (U.S.) (Graduate Research Fellowship)National Science Foundation (U.S.) (CAREER Award (0546262))National Science Foundation (U.S.) (NSF contract (0705677))National Science Foundation (U.S.) (Career Award (0747120)

    Surface heat flux feedback controlled impurity seeding experiments with Alcator C-Mod’s high-Z vertical target plate divertor: performance, limitations and implications for fusion power reactors

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    The Alcator C-Mod team has recently developed a feedback system to measure and control surface heat flux in real-time. The system uses real-time measurements of surface heat flux from surface thermocouples and a pulse-width modulated piezo valve to inject low-Z impurities (typically N2) into the private flux region. It has been used in C-Mod to mitigate peak surface heat fluxes >40 MW m−2 down to 1. While the system works quite well under relatively steady conditions, use of it during transients has revealed important limitations on feedback control of impurity seeding in conventional vertical target plate divertors. In some cases, the system is unable to avoid plasma reattachment to the divertor plate or the formation of a confinement damaging x-point MARFE. This is due to the small operational window for mitigated heat flux in the parameters of incident plasma heat flux, plasma density, and impurity density as well as the relatively slow response of the impurity gas injection system compared to plasma transients. Given the severe consequences for failure of such a system to operate reliably in a reactor, there is substantial risk that the conventional vertical target plate divertor will not provide an adequately controllable system in reactor-class devices. These considerations motivate the need to develop passively stable, highly compliant divertor configurations and experimental facilities that can test such possible solutions

    Factors predicting pain and early discontinuation of tumour necrosis factor-α-inhibitors in people with rheumatoid arthritis: Results from the British Society for Rheumatology Biologics Register

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    Background: We examined pain levels in 2 cohorts assembled from the British Society for Rheumatology Biologics Register (BSRBR), and investigated which factors predicted Bodily Pain scores and discontinuation of TNFα-inhibitors. Method: Data were retrieved from BSRBR-RA databases for up to 1 year after commencing TNFα-inhibitors (n=11995) or being treated with non-biologic therapies (n=3632). Bodily Pain scores were derived from the Short Form-36 (SF36) questionnaire and norm-transformed to allow comparison with UK population averages. Discontinuation data were from physician reports. Other data, including 28-joint disease activity score (DAS28) measurements, were from clinical examination, interview, medical records and self-report questionnaires. DAS28-P was derived as the proportion of DAS28 attributed to patient-reported factors (tender joint count and visual analogue score). Missing baseline variables from both cohorts were imputed into 20 replicate datasets. Odds ratios (OR) and adjusted OR were calculated for higher than median pain within each cohort. Results: Participants reported moderate to severe pain at baseline, and pain scores remained >1SD worse than normal population standards at 1 year, even when disease activity responded to treatment. Baseline pain was associated with DAS28-P, worse physical function, worse mental health, and DAS28. After logistic regression, independent predictors of higher than median pain at follow up were baseline Bodily Pain score, higher DAS28-P, worse physical function or mental health and co-morbidities. Higher age, male gender, and higher BMI were additional independent predictors of higher pain in participants who received TNFα-inhibitors. Baseline pain was also one of the predictors of discontinuation of the first TNFα-inhibitor within 1 year, as were female gender, current smoking, co-morbidities, extra-articular manifestations and worse function. Conclusion: Pain persists in people with treated RA, even in those for whom inflammation responds to treatment. Worse pain outcomes are predicted by factors different to those typically found to predict inflammatory disease activity in other studies. Worse pain at baseline also predicts discontinuation of TNFα-inhibitors. Improved pain management should complement inflammatory disease suppression in RA
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