173 research outputs found
Challenges in estimating soil water
[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
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
Impact of soil conditions on hydrology and water quality for a brown clay in the north-eastern cereal zone of Australia
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
Turning conceptual systems maps into dynamic simulation models: An Australian case study for diabetes in pregnancy
Background: System science approaches are increasingly used to explore complex public health problems. Quantitative methods, such as participatory dynamic simulation modelling, can mobilise knowledge to inform health policy decisions. However, the analytic and practical steps required to turn collaboratively developed, qualitative system maps into rigorous and policy relevant quantified dynamic simulation models are not well described. This paper reports on the processes, interactions and decisions that occurred at the interface between modellers and end-user participants in an applied health sector case study focusing on diabetes in pregnancy.
Methods: An analysis was conducted using qualitative data from a participatory dynamic simulation modelling case study in an Australian health policy setting. Recordings of participatory model development workshops and subsequent meetings were analysed and triangulated with field notes and other written records of discussions and decisions. Case study vignettes were collated to illustrate the deliberations and decisions made throughout the model development process.
Results: The key analytic objectives and decision-making processes included: defining the model scope; analysing and refining the model structure to maximise local relevance and utility; reviewing and incorporating evidence to inform model parameters and assumptions; focusing the model on priority policy questions; communicating results and applying the models to policy processes. These stages did not occur sequentially; the model development was cyclical and iterative with decisions being re-visited and refined throughout the process. Storytelling was an effective strategy to both communicate and resolve concerns about the model logic and structure, and to communicate the outputs of the model to a broader audience.
Conclusion: The in-depth analysis reported here examined the application of participatory modelling methods to move beyond qualitative conceptual mapping to the development of a rigorously quantified and policy relevant, complex dynamic simulation model. The analytic objectives and decision-making themes identified provide guidance for interpreting, understanding and reporting future participatory modelling projects and methods
Strong electronic correlations in superconducting organic charge transfer salts
We review the role of strong electronic correlations in
quasi--two-dimensional organic charge transfer salts such as (BEDT-TTF),
(BETS) and -[Pd(dmit)]. 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 Climate Challenge for Agriculture and the Value of Climate Services: Application to Coffee-Farming in Peru
The use of climate information in economic activities, typically provided by climate services, may serve as a possible adaptation strategy to changing climate conditions. The present paper analyzes the value of climate services aimed at improving agricultural productivity through a reduction in weather-associated risks. In the first part, we provide a theoretical foundation for estimating the value of climate services by proposing a stochastic life-cycle model of a rural household which faces uncertainty with respect to the timing and the size of an adverse weather shock. We subsequently calibrate the model to match the environment of coffee producers in the Cusco region of Peru and provide a range of estimates for the value of climate services for a single average household, the region, and the country as a whole. In the second part of the paper we use empirical data to verify the numerical estimates. We assess the value of climate services in the agricultural sector in Cusco based on a choice experiment approach. Data are analyzed using a standard as well as a random parameter logit model allowing for preference heterogeneity. Farmers show a significant willingness-to-pay for enhanced climate services which is particularly related to the service accuracy and geographic resolution. On average, the yearly value of a climate service in the coffee sector is found to be in the range 21.10 per hectare and 8.2 million for Peru as a whole
The clinical relevance of oliguria in the critically ill patient : Analysis of a large observational database
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
Surviving Sepsis Campaign: International guidelines for management of severe sepsis and septic shock: 2008
SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Pain distress : the negative emotion associated with procedures in ICU patients
The intensity of procedural pain in intensive care unit (ICU) patients is well documented. However, little is known about procedural pain distress, the psychological response to pain. Post hoc analysis of a multicenter, multinational study of procedural pain. Pain distress was measured before and during procedures (0-10 numeric rating scale). Factors that influenced procedural pain distress were identified by multivariable analyses using a hierarchical model with ICU and country as random effects. A total of 4812 procedures were recorded (3851 patients, 192 ICUs, 28 countries). Pain distress scores were highest for endotracheal suctioning (ETS) and tracheal suctioning, chest tube removal (CTR), and wound drain removal (median [IQRs] = 4 [1.6, 1.7]). Significant relative risks (RR) for a higher degree of pain distress included certain procedures: turning (RR = 1.18), ETS (RR = 1.45), tracheal suctioning (RR = 1.38), CTR (RR = 1.39), wound drain removal (RR = 1.56), and arterial line insertion (RR = 1.41); certain pain behaviors (RR = 1.19-1.28); pre-procedural pain intensity (RR = 1.15); and use of opioids (RR = 1.15-1.22). Patient-related variables that significantly increased the odds of patients having higher procedural pain distress than pain intensity were pre-procedural pain intensity (odds ratio [OR] = 1.05); pre-hospital anxiety (OR = 1.76); receiving pethidine/meperidine (OR = 4.11); or receiving haloperidol (OR = 1.77) prior to the procedure. Procedural pain has both sensory and emotional dimensions. We found that, although procedural pain intensity (the sensory dimension) and distress (the emotional dimension) may closely covary, there are certain factors than can preferentially influence each of the dimensions. Clinicians are encouraged to appreciate the multidimensionality of pain when they perform procedures and use this knowledge to minimize the patient's pain experience.Peer reviewe
- …