235 research outputs found

    Challenges in estimating soil water

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    [Introduction]: Most of Australia’s dryland cropping is characterised by unreliable rainfall with frequent long gaps between falls. Stored soil water is therefore essential to support crop growth during the growing season while water stored during fallows has varying importance, depending on soil type and rainfall patterns in relation to cropping periods. For example, a winter crop at Walpeup in Victoria derives 10% of its water supply from soil water at planting while a winter crop at Emerald will access 80% of its water supply from stored soil water (Thomas et al 2007). Even when dependence on stored water is small, extra water can make a valuable difference to crop yield and profitability, especially in typical dry-finish seasons (Kirkegaard et al 2014). An understanding of available water before a crop is planted can influence management decisions (area planted, fertilizer rates). Estimating plant available water (PAW) also requires an estimate of a soils ability to store water, its plant available water capacity (PAWC). This paper presents some observations of soil water from a 17-year study comparing water balances (runoff, evaporation and deep drainage) for a set of small contour bay catchments near Roma in southern Queensland. Our aim is to demonstrate some of the challenges associated with field measurement of both PAWC and PAW. This analysis is an extension of a detailed description of the development of SoilWaterApp (Freebairn et al. 2018)

    Impact of soil conditions on hydrology and water quality for a brown clay in the north-eastern cereal zone of Australia

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    Hydrology and water quality impacts of alternative land management practices are poorly quantified for semi-arid environments in the northern Australia cropping zone, yet wide-scale changes in tillage practices and land use were being recommended based on experience from other environments. The objective of this study was to explore changes in soil profile and catchment hydrology and water quality associated with different soil surface conditions created by different tillage and grazing practices. Soil water, runoff, and suspended sediment concentrations were monitored on 4 contour bay catchments over an 18-year period. Soil conditions were described by soil moisture, soil cover, and surface roughness in order to explore functional relationships between management, hydrology, and water quality. The site was chosen to represent the drier margins of cropping in southern Queensland where clay soils with high water-holding capacity, in conjunction with fallowing to store water for later crop growth, are an essential risk management tool. Accumulation of soil water in fallows was inefficient, with fallow efficiencies ranging from 7 to 40% due to high evaporation and runoff losses. Runoff amount was determined by soil water content, which was strongly influenced by antecedent rainfall, water use, and evaporation patterns. Surface cover and roughness had subtle influences on runoff, and a greater effect on suspended sediment concentration. Runoff and suspended sediment losses were considerably lower under pasture than cropping. A participative approach between farmers and scientists was demonstrated to be an efficient method to carry out an extensive and long-term catchment study at a remote location. This study provides benchmark data for future hydrologic and water quality investigations. © CSIRO 2009

    Presenting a comprehensive multi-scale evaluation framework for participatory modelling programs: a scoping review

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    INTRODUCTION: Systems modelling and simulation can improve understanding of complex systems to support decision making, better managing system challenges. Advances in technology have facilitated accessibility of modelling by diverse stakeholders, allowing them to engage with and contribute to the development of systems models (participatory modelling). However, despite its increasing applications across a range of disciplines, there is a growing need to improve evaluation efforts to effectively report on the quality, importance, and value of participatory modelling. This paper aims to identify and assess evaluation frameworks, criteria, and/or processes, as well as to synthesize the findings into a comprehensive multi-scale framework for participatory modelling programs. MATERIALS AND METHODS: A scoping review approach was utilized, which involved a systematic literature search via Scopus in consultation with experts to identify and appraise records that described an evaluation framework, criteria, and/or process in the context of participatory modelling. This scoping review is registered with the Open Science Framework. RESULTS: The review identified 11 studies, which varied in evaluation purposes, terminologies, levels of examination, and time points. The review of studies highlighted areas of overlap and opportunities for further development, which prompted the development of a comprehensive multi-scale evaluation framework to assess participatory modelling programs across disciplines and systems modelling methods. The framework consists of four categories (Feasibility, Value, Change/Action, Sustainability) with 30 evaluation criteria, broken down across project-, individual-, group- and system-level impacts. DISCUSSION & CONCLUSION: The presented novel framework brings together a significant knowledge base into a flexible, cross-sectoral evaluation effort that considers the whole participatory modelling process. Developed through the rigorous synthesis of multidisciplinary expertise from existing studies, the application of the framework can provide the opportunity to understand practical future implications such as which aspects are particularly important for policy decisions, community learning, and the ongoing improvement of participatory modelling methods

    Participatory systems modelling for youth mental health: an evaluation study applying a comprehensive multi-scale framework

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    The youth mental health sector is persistently challenged by issues such as service fragmentation and inefficient resource allocation. Systems modelling and simulation, particularly utilizing participatory approaches, is offering promise in supporting evidence-informed decision making with limited resources by testing alternative strategies in safe virtual environments before implementing them in the real world. However, improved evaluation efforts are needed to understand the critical elements involved in and to improve methods for implementing participatory modelling for youth mental health system and service delivery. An evaluation protocol is described to evaluate the feasibility, value, impact, and sustainability of participatory systems modelling in delivering advanced decision support capabilities for youth mental health. This study applies a comprehensive multi-scale evaluation framework, drawing on participatory action research principles as well as formative, summative, process, and outcome evaluation techniques. Novel data collection procedures are presented, including online surveys that incorporate gamification to enable social network analysis and patient journey mapping. The evaluation approach also explores the experiences of diverse stakeholders, including young people with lived (or living) experience of mental illness. Social and technical opportunities will be uncovered, as well as challenges implementing these interdisciplinary methods in complex settings to improve youth mental health policy, planning, and outcomes. This study protocol can also be adapted for broader international applications, disciplines, and contexts

    Strong electronic correlations in superconducting organic charge transfer salts

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    We review the role of strong electronic correlations in quasi--two-dimensional organic charge transfer salts such as (BEDT-TTF)2X_2X, (BETS)2Y_2Y and β\beta'-[Pd(dmit)2_2]2Z_2Z. We begin by defining minimal models for these materials. It is necessary to identify two classes of material: the first class is strongly dimerised and is described by a half-filled Hubbard model; the second class is not strongly dimerised and is described by a quarter filled extended Hubbard model. We argue that these models capture the essential physics of these materials. We explore the phase diagram of the half-filled quasi--two-dimensional organic charge transfer salts, focusing on the metallic and superconducting phases. We review work showing that the metallic phase, which has both Fermi liquid and `bad metal' regimes, is described both quantitatively and qualitatively by dynamical mean field theory (DMFT). The phenomenology of the superconducting state is still a matter of contention. We critically review the experimental situation, focusing on the key experimental results that may distinguish between rival theories of superconductivity, particularly probes of the pairing symmetry and measurements of the superfluid stiffness. We then discuss some strongly correlated theories of superconductivity, in particular, the resonating valence bond (RVB) theory of superconductivity. We conclude by discussing some of the major challenges currently facing the field.Comment: A review: 52 pages; 10 fig

    The clinical relevance of oliguria in the critically ill patient : Analysis of a large observational database

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    Funding Information: Marc Leone reports receiving consulting fees from Amomed and Aguettant; lecture fees from MSD, Pfizer, Octapharma, 3 M, Aspen, Orion; travel support from LFB; and grant support from PHRC IR and his institution. JLV is the Editor-in-Chief of Critical Care. The other authors declare that they have no relevant financial interests. Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Urine output is widely used as one of the criteria for the diagnosis and staging of acute renal failure, but few studies have specifically assessed the role of oliguria as a marker of acute renal failure or outcomes in general intensive care unit (ICU) patients. Using a large multinational database, we therefore evaluated the occurrence of oliguria (defined as a urine output 16 years) patients in the ICON audit who had a urine output measurement on the day of admission were included. To investigate the association between oliguria and mortality, we used a multilevel analysis. Results: Of the 8292 patients included, 2050 (24.7%) were oliguric during the first 24 h of admission. Patients with oliguria on admission who had at least one additional 24-h urine output recorded during their ICU stay (n = 1349) were divided into three groups: transient - oliguria resolved within 48 h after the admission day (n = 390 [28.9%]), prolonged - oliguria resolved > 48 h after the admission day (n = 141 [10.5%]), and permanent - oliguria persisting for the whole ICU stay or again present at the end of the ICU stay (n = 818 [60.6%]). ICU and hospital mortality rates were higher in patients with oliguria than in those without, except for patients with transient oliguria who had significantly lower mortality rates than non-oliguric patients. In multilevel analysis, the need for RRT was associated with a significantly higher risk of death (OR = 1.51 [95% CI 1.19-1.91], p = 0.001), but the presence of oliguria on admission was not (OR = 1.14 [95% CI 0.97-1.34], p = 0.103). Conclusions: Oliguria is common in ICU patients and may have a relatively benign nature if only transient. The duration of oliguria and need for RRT are associated with worse outcome.publishersversionPeer reviewe
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