Now showing 1 - 10 of 498
  • Publication
    Strategic Management of Grazing Grassland Systems to Maintain and Increase Organic Carbon in Soils
    Understanding management-induced C sequestration potential in soils under agriculture, forestry, and other land use systems and their quantification to offset increasing greenhouse gases are of global concern. This chapter reviews management-induced changes in C storage in soils of grazing grassland systems, their impacts on ecosystem functions, and their adaptability and needs of protection across socio-economic and cultural settings. In general, improved management of grassland/pasture such as manuring/slurry application, liming and rotational grazing, and low to medium livestock units could sequester C more than under high intensity grazing conditions. Converting cultivated land to pasture, restoration of degraded land, and maximizing pasture phases in mixed-cropping, pasture with mixed-livestock, integrated forestry-pasturage of livestock (silvopastoral) and crop-forestry-pasturage of livestock (agro-silvopastoral) systems could also maintain and enhance soil organic C density (SOCρ). In areas receiving low precipitation and having high erodibility, grazing exclusion might restore degraded grasslands and increase SOCρ. Yet, optimizing C sequestration rates, sowing of more productive grass varieties, judicial inorganic and organic fertilization, rotational grazing, and other climate-resilient approaches could improve overall farm productivity and profitability and attain sustainability in livestock farming systems.
      779
  • Publication
    Recorded energy consumption of nZEB dwellings and corresponding interior temperatures: Initial results from the Irish nZEB101 project
    (University of A Coruña & Asoc. PLEA 2020 Planning Post Carbon Cities, 2020-09-03) ; ; ; ;
    Ireland is mandating the unprecedented mass market deployment of low-energy dwellings via the near Zero Energy Buildings (nZEB) standard, from 1 January 2021 due to the EU wide Energy Performance of Buildings Directive (EPBD). This is among the first academic papers to provide recorded energy and temperature data for nZEB compliant dwellings in Ireland. It reports on initial results of the www.nZEB101.ie Post Occupancy Evaluation project, the objective of which is to uncover key nZEB design and operations lessons, to aid the next iteration of the country's building regulations. This paper reports on the analysis of winter temperatures and the energy consumption of 17 nZEB compliant dwellings, each of which have been monitored for at least a 12 month period. While analysis of further properties is needed to further validate the findings, key findings to date include significantly higher than expected interior temperatures and energy consumption, and a usage profile which is significantly different from the assumptions in the DEAP National energy rating software.
      268
  • Publication
    A modelling framework for the prediction of the herd-level probability of infection from longitudinal data
    The collective control programmes (CPs) that exist for many infectious diseases of farm animals rely on the application of diagnostic testing at regular time intervals for the identification of infected animals or herds. The diversity of these CPs complicates the trade of animals between regions or countries because the definition of freedom from infection differs from one CP to another. In this paper, we describe a statistical model for the prediction of herd-level probabilities of infection from longitudinal data collected as part of CPs against infectious diseases of cattle. The model was applied to data collected as part of a CP against bovine viral diarrhoea virus (BVDV) infection in Loire-Atlantique, France. The model represents infection as a herd latent status with a monthly dynamics. This latent status determines test results through test sensitivity and test specificity. The probability of becoming status positive between consecutive months is modelled as a function of risk factors (when available) using logistic regression. Modelling is performed in a Bayesian framework, using either Stan or JAGS. Prior distributions need to be provided for the sensitivities and specificities of the different tests used, for the probability of remaining status positive between months as well as for the probability of becoming positive between months. When risk factors are available, prior distributions need to be provided for the coefficients of the logistic regression, replacing the prior for the probability of becoming positive. From these prior distributions and from the longitudinal data, the model returns posterior probability distributions for being status positive for all herds on the current month. Data from the previous months are used for parameter estimation. The impact of using different prior distributions and model implementations on parameter estimation was evaluated. The main advantage of this model is its ability to predict a probability of being status positive in a month from inputs that can vary in terms of nature of test, frequency of testing and risk factor availability/presence. The main challenge in applying the model to the BVDV CP data was in identifying prior distributions, especially for test characteristics, that corresponded to the latent status of interest, i.e. herds with at least one persistently infected (PI) animal. The model is available on Github as an R package (https://github.com/AurMad/STOCfree) and can be used to carry out output-based evaluation of disease CPs.
      54
  • Publication
    Early Medieval Dwellings and Settlements in Ireland, AD 400-1100: Vol. 1 Text.
    (The Early Medieval Archaeology Project (EMAP), 2010-12-01) ; ; ;
    Early medieval settlement archaeology utterly dominates the record of excavations in Ireland, including settlement enclosures, complexes, landscapes and ecclesiastical sites (O'Sullivan, McCormick, Kerr & Harney 2009). For this reason, the INSTAR-funded Early Medieval Archaeology Project (EMAP) focused its research in 2009-2010, on dwellings and settlements (having previously provided a review of all early medieval archaeological excavations in Ireland). In 2009, EMAP first prepared a gazetteer of what we would regard as Ireland’s key early medieval settlements and dwelling excavations, largely based on a detailed review of the original EMAP database, 1930-2004; amounting to a final gazetteer (see Vol II) of 241 early medieval settlements revealed through archaeological excavation, 1930-2009. The first draft of the Vol. II gazetteer was first completed in a five-month period between July and December 2009 (Kerr et. al 2009) and was edited and expanded in 2010. In 2010, EMAP built further on this achievement, to research and complete a vol. I interpretative text that would precede the Vol II gazetteer, thus providing a reflection and analysis of such themes as houses and buildings, the organisation of settlement enclosures, agricultural activity and crafts and industry. This two volume report, completed in December 2010, arguably represents the first compilation, analysis and discussion of early medieval settlement archaeology in Ireland, as revealed through excavations, 1930-2009.
      1709
  • Publication
    The contribution of rare species to a community's resilience
    (British Ecological Society, 2018-07-09) ; ; ;
    Theoretical results for generalised Lotke-Volterra systems that demonstrate the role of rare species in determining the characteristic return time of the system.
      117
  • Publication
    Bayesian Case-Exclusion and Explainable AI (XAI) for Sustainable Farming
    Smart agriculture (SmartAg) has emerged as a rich domain for AI-driven decision support systems (DSS); however, it is often challenged by user-adoption issues. This paper reports a case-based reasoning system, PBI-CBR, that predicts grass growth for dairy farmers, that combines predictive accuracy and explanations to improve user adoption. PBI-CBR’s key novelty is its use of Bayesian methods for case-base maintenance in a regression domain. Experiments report the tradeoff between predictive accuracy and explanatory capability for different variants of PBI-CBR, and how updating Bayesian priors each year improves performance.
      353
  • Publication
    Comparison of the confidence in freedom from infection based on different control programmes between EU member states: STOC free
    The STOC free project constructed a generic framework that allows a standardised and harmonised description of different control programmes (CP) for cattle diseases. The STOC free model can be used to determine the confidence of freedom from infection that has been achieved in disease CPs, in support of an ongoing assessment of progress towards output-based standards as outlined in the EU Animal Health Law. With this information, and as required, further CP actions can be taken to mitigate the risks of persistence and (re-)introduction on the probability of freedom from infection. Bovine viral diarrhoea virus (BVDV) was chosen as the case disease because of the diversity in CPs in the six participating countries. A Bayesian hidden Markov model was considered the best modelling method. Detailed BVDV CP information was collected in the participating countries and the key aspects for inclusion in the STOC free model were identified. A first version of STOC free model was developed and tested on simulated data. The risk factors for BVDV infection that needed to be included in the model were defined and default values for these risk factors were quantified. A data collection tool was finalised with which the data for the STOC free model was collected. Subsequently, the developed model was tested and validated using real BVDV CP data from partner countries. Based on the feedback, the model was finalised and the report and corresponding computer code were made publicly available. There were roughly three different BVDV situations that occurred in the partner countries: 1. Endemic situation with a CP operating at herd level, 2. Endemic situation with a CP operating at animal level and 3. BVD free situation. The STOC free model is able to include herd level data only and animal level data has to be aggregated to herd level before the model can be applied. The STOC free model is not applicable for a country that is completely BVDV free given that it needs some infections to estimate its parameters and converge. In the latter situation, a scenario tree model could be a better suited tool, and this was evaluated in the Swedish case study. Further work is needed for generalisation of the method to other diseases and expansion of the method to include socioeconomic aspects of CPs.
      253
  • Publication
    Validation of a Front-Tracking Model of the Columnar to Equiaxed Transition using Solidification Results from the Maxus 7 Microgravity Platform
    (The Japan Society of Microgravity Application, 2008-03) ; ; ; ;
    To study the columnar-to-equiaxed transition (CET) in alloy castings, three aluminum-silicon samples were solidified onboard the MAXUS 7 sounding rocket. Temperature measurements were made during the flight and the samples were retrieved and analyzed for their solidified macrostructure. Two of the samples produced a CET while the third sample produced a mixed structure with grains nucleating on the crucible walls. A novel front tracking model of solidification and a model of the MACE test apparatus are presented. Validation of the solidification code is carried out. Cooling curves from the experiments are predicted. A simulation of the solidified macrostructure is also given for each experiment. The CET positions are predicted in agreement with the experimental results.
      73
  • Publication
    Model Transformation from SimModel to Modelica for Building Energy Performance Simulation
    (International Building Performance Simulation Association (IBPSA), 2014-09-01) ; ; ;
    This paper demonstrates a model transformation tool between the Building Information Model (BIM) and Modelica schemas for Building Energy Performance Simulation (BEPS) purposes. Automated reuse of data in BIMs to accelerate BEPS model development is now a promising approach for engineers. However, using BEPS tools such as Modelica to generate building simulation models is currently difficult and time consuming due to the largely manual data input. The ability to import data of a BIM into Modelica-based BEPS tool would improve this process significantly. In order to address the challenge, this paper proposes a model transformation prototype to convert Industry Foundation Classes (IFC) based BIMs into object-oriented Modelica simulation models. The proposed approach uses SimModel data model as a placeholder for IFC. SimModel currently contains richer HVAC data definitions than IFC for the purposes of BEPS and can be easily extended to store the additional data required by Modelica. This prototype demonstrates the potential to reduce development time of Modelica models by reusing building information data stored in BIMs.
      166
  • Publication
    Managing legacy soil phosphorus in grassland soils for agricultural productivity and environmental quality: a review
    Phosphorus (P) is a lithophile element that tends to accumulate in the solid phase at the Earth’s surface and has a low water solubility. As P is a limiting nutrient for plant growth in most terrestrial systems, P in fertilizers has been a major factor underpinning global agricultural production in the 20th and early 21st centuries, including that from grassland. However, P is a costly farm input and it is also a finite mineral resource. Best agronomic practice is to maintain soil P levels at optimum over the medium-to-long term by managing P application and offtake. However, in some cases, soil P levels have been built up in excess of agronomic optimum due to P application driven by organic “waste disposal” or with the intention of building up a “bank” of soil P for future use. This has been associated with P losses to surface waters and impacts on water quality. Legislation, policy and best management practice advice in many countries has attempted to affect these legacy high P soils through a range of measures. In Ireland, for example, the Good Agricultural Practice measures, introduced in 2006 under the Irish Nitrates Action Plan, attempt to impose P deficits on soils with high P. National data shows that P fertilizer use declined by 55% on grassland soils between 2003 and 2008 and would suggest that soils with high soil P levels dropped from 30% in 2007 to 22% in 2011. This paper presents a review of the international literature on legacy excessive P in grassland soils, management practices and policy measures to manage them, and changes in soil P in response to such measures. Consideration is given to both agronomic and environmental concerns. There are a number of factors in grassland production systems, and particularly dairy production systems based on grazed grass, that differ from other agricultural production systems. For example, offtakes are typically lower than in tillage and the recycling of P, either by animal deposition or spreading of manures, gives less control to the farmer. Important questions addressed include: how quickly do grassland soil P levels decline under situations of negative P balance?; what fractions of P control soil P decline?; what grassland management practices are important in determining where and how fast soil P levels decline?; and what scale is appropriate to implement practice change and monitor effects?
      98