Functional responses can’t unify invasion ecology

Dick et al. (Biol Invasions, 2017) propose that the comparative functional response framework provides a unifying approach for the study of invasive species. We agree that functional responses are an important and powerful quantitative description of consumer effects on resources, and co-opting classical ecological theory to better predict invasive species impacts is a laudable move for invasion biology. However, we fear that the early successes of select examples of the comparative functional response (CFR) approach has led Dick et al. to exaggerate the generality of its utility, and about its ability to unify the field. Further, they fail to provide a convincing argument why CFR is better than existing tools such as invasion history or impact indices, even when considering emerging or potential invaders. In this response we provide details of three conceptual issues stemming from classical ecological theoretical frameworks and two practical problems that Dick et al. and other CFR proponents need to address

Development of a computationally efficient model for the control of Ziegler-Natta catalysed industrial production of high density polyethylene

High density polyethylene is commonly produced by the slurry phase co-polymerisation of ethylene and other alkenes, using heterogeneous titanium-based Ziegler-Natta catalysts. During grade transitions, when reactor conditions are manipulated to change polymer properties, significant quantities of off-specification product result. Implementing a model-predictive controller based on a dynamic reactor model may allow for minimising losses during unsteady-state operation. Such a model must be developed from a fundamental understanding of polymerisation reaction kinetics and the interaction of effects at various scales, including those of catalyst sites, catalyst/polymer particles and reactor hydrodynamics. The model must also be computationally efficient enough for application to real-time control. The recently-developed pseudo-sites model was used as a fundamental kinetic explanation of polymer property distributions and catalyst activity profiles, in contrast to empirical multi-site models. Laboratory polymerisation experiments were performed at industrially-relevant conditions. Kinetic parameters were fitted to the data, using a novel proposed regression procedure to extract meaningful kinetic parameters. A dynamic reactor model was developed, based on the Segregation Approach. Whereas the more common Population Balance Model must consider multivariate distributions of population members within a chosen volume and requires partial differential equation solution, the Segregation Approach can generate the moments of a distribution by evaluating the evolution of properties without requiring solution over the whole volume. The Segregation Approach and PBM were rigorously compared in the context of Particle Size Distributions, and the Segregation Approach shown to be an order of magnitude more computationally efficient. Steady-state industrial data was used to reconcile model predictions for laboratory and industrial polymerisation. This was the first application of the pseudo-sites model to laboratory data, and first extension to industrial scale. Unsteady-state data from three industrial grade transitions was used to validate the reactor model, which closely matched industrial reactor performance. The model simulated 30-40 hours of real time in 15-25 seconds of calculation time. The reactor model was used to propose improved grade transition strategies; transition duration and waste production were improved by 20-40%. The reactor model has been shown to accurately reproduce real-world results, and is computationally efficient enough to be applied to model-based control applications

Adoption of natural gas for residential heating. ESRI Research Bulletin, 2018/03

The focus of this research is the adoption of gas central heating in Ireland, in particular understanding the time-lag of adoption of more efficient heating methods, once available. Public policy interest in residential fuel choice centres on encouraging fuel switching away from carbon intensive fuels, such as peat and coal, to less carbon intensive fuels, such as gas or renewables. The residential sector accounts for approximately one-quarter of final energy consumption in Ireland, while within the residential sector space and water heating account for approximately 80% of energy use. Reducing the carbon intensity of residential energy is particularly important given Irish and EU targets for greenhouse gas emissions as a means of contributing to international efforts to limit global warming below 2°C

The Teaching Methods of Jesus

Jesus was the Master Teacher. This was recognized by the great leaders of His day, by His followers, and through the ages by Christians right up to today. If we recognize our calling to teaching, even though we might have been trained via methods courses or have come to our positions because of experience and years of study, what better way to gauge our teaching ability than by finding out how Jesus taught and carrying that over into our classrooms today? This paper will explore the methods Jesus used to get His message across to the people of His day and to teach His lessons to His disciples. This paper could lead to the development of a required course for student teachers on Jesus’ methods of teaching

Medium-Term Review: 1991-1996, No. 4 June 1991

Our medium-term forecast for the period 1991-96 is for a pattern of resumed, steady growth in GNP, after a temporary slow-down this year. The average rate of growth should be in the region of 3.5% per annum, a slower growth than was anticipated prior to the downward revisions of the prospects for the world economy made over the last two years. In particular, the rise in German interest rates, consequent on unification, has reduced the prospective Irish growth rate in the medium-term by 0.5%

Issues in Irish Energy Policy. ESRI Policy Series No. 20. December 1993

In the past public interest in energy policy has fluctuated with movements in energy prices; when prices were exceptionally high interest peaked. Since 1986, when energy prices fell precipitately, energy policy has attracted much less public attention or scrutiny both internationally and in Ireland. However, the cost of energy to the economy still remains substantial to both the household and the productive sector. As an important input to industry, movements in domestic energy prices can significantly affect Irish competitiveness. The Report of the lndustrial Policy Review Group (1992), among others, has highlighted this issue. In addition, technical change, the growing attention to the environmental consequences of burning fossil fuels, and developments in the EC are posing new challenges for policy requiring a re-examination of our traditional outlook