Empirical Agent-Based Modelling for exploring Intergroup Contact in a Segregated Society

Agent-based modelling has a long history of application in the study of segregation, but is rarely deployed beyond the examination of residential segregation. This study leverages multiple datasets: including census, survey, PGIS and GPS traces; in order to create an empirical agent-based model for the exploration of mobility practices between segregated communities in Belfast (Northern Ireland). In doing so, we are able to conduct novel examinations into the impact of day-to-day mobility choices upon intergroup attitudes and activity-space segregation; with policy implications for understanding and combatting segregation in cities around the world

Ammonia reduction by trees (ART). Summary report

The aim of Ammonia Reduction by Trees (ART) project was to provide new scientific evidence on tree planting for reducing the impact of ammonia emissions from farming to inform better advice, guidance and incentives for farmers on ammonia mitigation through treebelt planting

Counting the cost of the Niger Delta's largest oil spills:Satellite remote sensing reveals extensive environmental damage with >1million people in the impact zone

The Niger Delta has a long history of oil and gas exploration and production, but this has come with a heavy environmental cost arising from oil spills and other pollution events. Two oil spills in Ogoniland in 2008/9 were by far the largest in terms of both duration (149 days combined) and magnitude (82,939,170 l combined), but little is understood about the extent of impact of these events because traditional field-based surveys are virtually impossible in this region. In this study, the normalised difference vegetation index, a technique used for measuring plant health, was applied to multi-temporal satellite images to delineate an extensive area of 393 km2 that has experienced vegetation mortality resulting from the oil pollution. These effects persist to present and are exacerbated by continuing subsequent spill events. Independently collected field samples confirmed the high concentrations of hydrocarbon pollutants in the impact area. The extensive tidal river network and mangrove swamps have facilitated the spread of oil, with the delta becoming a sink for the oil that is dispersed but not removed. Over 1 million people live within the area contaminated by oil and have potentially been exposed to pollution through direct and indirect pathways over a prolonged period. The population in the impact area is particularly vulnerable to chronic illness due to its young age structure and pre-existing very low life expectancy. Hence, there is an urgent need to mitigate the impacts of the pollution on environmental and human health. The novelty of this work is that satellite remote sensing allows the impacts of pollution to be monitored across large areas in a geographically remote and challenging environment. The outputs from this study could be used to guide the future spatial targeting of the limited remediation resources that are available, to achieve positive outcomes. © 2021 Elsevier B.V

Development and application of a model for calculating the risk of stem and root lodging in maize

Lodging is a major constraint to increasing the global productivity of maize (Zea Maize L.). The objectives of this paper are to: i) describe a model for stem and root lodging in maize, ii) calibrate the anchorage strength component of the model, iii) evaluate the model's applicability by assessing its capacity to explain effects of crop husbandry on lodging risk and iv) investigate the potential to further develop the lodging model to predict lodging risk at an early enough growth stage for tactical agronomic action to minimise lodging risk. The study involved a multidisciplinary collaboration between crop scientists, wind engineers and geospatial scientists in the UK and China. Three field experiments with plant population density and nitrogen (N) fertiliser rate treatments were conducted in the UK and China to develop and test the lodging model. Plant characteristics associated with lodging were measured in the experiments after flowering. An existing model of cereal anchorage strength that uses the spread of the root plate as its primary input was demonstrated to be applicable for maize and calibrated for this crop species. The lodging model's predictions of the effects of plant population and N fertiliser on lodging risk were consistent with published observations. The lodging model calculated that increasing the plant population significantly reduced the anchorage and stem failure wind speeds in all experiments, thus increasing the risk of lodging. This effect was primarily due to increased plant population reducing the spread of the root plate and the stem strength. Changes in N fertiliser had a smaller effect on the lodging associated plant characters. A sensitivity analysis showed that stem failure wind speed was influenced most by variation in stem strength and root failure wind speed was influenced most by variation in the spread of the root plate. This study has shown that the leaf area index measured at leaf 4, 6 or 8 stages is a good indicator of a crop's future risk of lodging, which demonstrates the potential to develop the model into a practical tool for predicting lodging risk in time for tactical agronomic decisions to be made during the crop's growing period. © 2020 Elsevier B.V

Urban form strongly mediates the allometric scaling of airshed pollution concentrations

Data supporting the paper "Urban form strongly mediates the allometric scaling of airshed pollution concentrations" by A. R. MacKenzie, J. D. Whyatt, M. J. Barnes, G. Davies, and C. N. Hewit

Urban form strongly mediates the allometric scaling of airshed pollution concentrations

Data supporting the paper "Urban form strongly mediates the allometric scaling of airshed pollution concentrations" by A. R. MacKenzie, J. D. Whyatt, M. J. Barnes, G. Davies, and C. N. Hewit

Directional passive ambient air monitoring of ammonia for fugitive source attribution:a field trial with wind tunnel characteristics

Atmospheric ammonia is a precursor for secondary particulate matter formation, which harms human health and contributes to acidification and eutrophication. Under the 2012 Gothenburg Protocol, 2005 emissions must be cut by 6% by 2020. In the UK, 83% of total emissions originate from agricultural practices such as fertiliser use and rearing of livestock, with emissions that are spatially extensive and variable in nature. Such fugitive emissions make resolving and tracking of individual site performance challenging. The Directional Passive Air quality Sampler (DPAS) was trialled at Whim Bog, an experimental site with a wind-controlled artificial release of ammonia, in combination with CEH-developed ammonia samplers. Whilst saturation issues were identified, two DPAS-MANDE (Mini Annular Denuder) systems, when deployed in parallel, displayed an average relative deviation of 15% (2–54%) across all 12 directions, with the directions exposed to the ammonia source showing ∼5% difference. The DPAS-MANDE has shown great potential for directional discrimination and can contribute to the understanding and management of fugitive ammonia sources from intensive agriculture sites

Determination of crop dynamic and aerodynamic parameters for lodging prediction

This paper considers a process through which the wind costs the agricultural industry hundreds of millions of pounds per year - crop lodging. Lodging is the displacement of crops by wind (and rain) that can result in either stem breakage or uprooting. In particular this paper builds upon recent work to develop a generalised model of the lodging process and presents the results of several experimental campaigns to identify dynamic and aerodynamic parameters that are required as inputs to the model in order to estimate lodging wind speeds. These experiments were carried out at various sites in the UK and the Republic of Ireland to determine the natural frequencies, damping ratios and drag areas of maize, oats and oil seed rape. The experimental methodology, which was based upon the tracking of plant displacements, was shown to be robust, and consistent values of the parameters were obtained, albeit with much larger experimental uncertainties than would normally be expected in wind engineering applications. The values of these parameters were also consistent with those of earlier measurements for wheat. The generalised model was then used to determine lodging wind speeds for the three crops, and an assessment was made of the effect of experimental uncertainties in dynamic, aerodynamic and agronomic variables on the predicted values. In broad terms the generalised lodging model was shown to well describe the crop behaviour for isolated crops, and it was shown that it could be used in a simplified form for interlocked crop canopies. It was also shown that uncertainties in the aerodynamic parameters resulted in uncertainties of around an order of magnitude in lodging risk, whilst typical variations between plants in some crop parameters (notably stem strength and radius) could result in lodging risk uncertainties of two orders of magnitude