2,177 research outputs found

    Sheep CRC Renewal Proposal: Economic Evaluation of the Proposed Scientific Themes

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    The Australian sheep industry and its associated research and development agencies have developed a proposal for the CRC for Sheep Industry Innovation. “Top-down” and “bottomup” procedures were used to assess the expected economic benefits from this proposal. Formal “with-CRC” and “without-CRC” scenarios were defined for each product and each research theme. Relevant costs were similarly defined. The requested investment by the Commonwealth and the Australian sheep industry in the CRC is assessed relative to a scenario where an alternative, lower cost research program into this industry is implemented. These extra resources have a discounted value of about 34millionoverthe25−yearperiodofthisevaluation.Theseresourcesaresufficienttoallowsomenewresearchcomponentstobeaddedtotheportfolio,someexistingcomponentstoproducebetteroutcomes,andamoretargetedapproachtodevelopmentandextensionthatspeedsupandincreasestheadoptionofthenewtechnologiesthataregeneratedbytheresearchprogram.Thebenefitfromthisextrainvestmentandconsequentresearcheffortisestimatedtobeworthabout34 million over the 25-year period of this evaluation. These resources are sufficient to allow some new research components to be added to the portfolio, some existing components to produce better outcomes, and a more targeted approach to development and extension that speeds up and increases the adoption of the new technologies that are generated by the research program. The benefit from this extra investment and consequent research effort is estimated to be worth about 518 million in present value terms, which is far in excess of the marginal investment. Thus every 1oftheseextraresourcesbroughtintotheAustraliansheepindustrythroughfundingtheproposedCRCisexpectedtoreturnaround1 of these extra resources brought into the Australian sheep industry through funding the proposed CRC is expected to return around 15.30 to the industry in present value terms.wool, sheep meat, research and development, economic, evaluation, Australia, Agribusiness, Livestock Production/Industries, Production Economics, Research and Development/Tech Change/Emerging Technologies, Q160,

    Economic benefits of public investment in weed management: the case of vulpia in south-eastern Australia’s temperate pasture areas

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    The present paper reports an economic evaluation of the long-term benefits to Australia of research by the Cooperative Research Centre for Weed Management Systems (CRC) into the improved management of vulpia , the major annual grass weed of temperate pastures in New South Wales and Victoria. Vulpia reduces livestock production by competition with more desirable pasture species, by the production of low quality feed at critical times of the grazing cycle, and by injury to animals. A 20-year stochastic benefit-cost analysis indicated that reducing the impacts of vulpia in these pastures produced a mean net present value of # A58.3 million and a mean benefit-cost ratio of 33:1. Temperate pasture zone wool producers would capture the largest shares of these benefits, Australian consumers would gain, but wool producers in the rest of Australia would suffer welfare losses from vulpia reductions in the temperate pasture zones.Agricultural and Food Policy, Farm Management,

    Dynamic finite-strain modelling of the human left ventricle in health and disease using an immersed boundary-finite element method

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    Detailed models of the biomechanics of the heart are important both for developing improved interventions for patients with heart disease and also for patient risk stratification and treatment planning. For instance, stress distributions in the heart affect cardiac remodelling, but such distributions are not presently accessible in patients. Biomechanical models of the heart offer detailed three-dimensional deformation, stress and strain fields that can supplement conventional clinical data. In this work, we introduce dynamic computational models of the human left ventricle (LV) that are derived from clinical imaging data obtained from a healthy subject and from a patient with a myocardial infarction (MI). Both models incorporate a detailed invariant-based orthotropic description of the passive elasticity of the ventricular myocardium along with a detailed biophysical model of active tension generation in the ventricular muscle. These constitutive models are employed within a dynamic simulation framework that accounts for the inertia of the ventricular muscle and the blood that is based on an immersed boundary (IB) method with a finite element description of the structural mechanics. The geometry of the models is based on data obtained non-invasively by cardiac magnetic resonance (CMR). CMR imaging data are also used to estimate the parameters of the passive and active constitutive models, which are determined so that the simulated end-diastolic and end-systolic volumes agree with the corresponding volumes determined from the CMR imaging studies. Using these models, we simulate LV dynamics from end-diastole to end-systole. The results of our simulations are shown to be in good agreement with subject-specific CMR-derived strain measurements and also with earlier clinical studies on human LV strain distributions

    Dynamic general equilibrium analysis of improved weed management in Australia's winter cropping systems

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    A recent analysis indicated that the direct financial cost of weeds to Australia’s winter grain sectorwas approximately A1.2bnin1998–1999.Costsofthismagnituderepresentalargerecurringproductivitylossinanagriculturalsectorthatissufficienttoimpactsignificantlyonregionaleconomies.Usingamulti−regionaldynamiccomputablegeneralequilibriummodel,wesimulatethegeneralequilibriumeffectsofahypotheticalsuccessfulcampaigntoreducetheeconomiccostsofweeds.WeassumethatanadditionalA1.2bn in 1998–1999. Costs of thismagnitude represent a large recurring productivity loss in an agricultural sector that is sufficient to impact significantly on regional economies.Using amulti-regional dynamic computable general equilibrium model, we simulate the general equilibrium effects of a hypothetical successful campaign to reduce the economic costs of weeds. We assume that an additional 50m of R&D spread over five years is targeted at reducing the additional costs and reduced yields arising from weeds in various broadacre crops. Following this R&D effort, one-tenth of the losses arising from weeds is temporarily eliminated, with a diminishing benefit in succeeding years. At the national level, there is a welfare increase of $700m in discounted net present value terms. The regions with relatively high concentrations of winter crops experience small temporary macroeconomic gains.CGE modelling, dynamics, weed management, Crop Production/Industries,

    Open-Path Fourier Transform Infrared Studies of Large-Scale Laboratory Biomass Fires

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    A series of nine large-scale, open fires was conducted in the Intermountain Fire Sciences Laboratory (IFSL) controlled-environment combustion facility. The fuels were pure pine needles or sagebrush or mixed fuels simulating forest-floor, ground fires; crown fires; broadcast burns; and slash pile burns. Mid-infrared spectra of the smoke were recorded throughout each fire by open path Fourier transform infrared (FTIR) spectroscopy at 0.12 cm−1 resolution over a 3 m cross-stack pathlength and analyzed to provide pseudocontinuous, simultaneous concentrations of up to 16 compounds. Simultaneous measurements were made of fuel mass loss, stack gas temperature, and total mass flow up the stack. The products detected are classified by the type of process that dominates in producing them. Carbon dioxide is the dominant emission of (and primarily produced by) flaming combustion, from which we also measure nitric oxide, nitrogen dioxide, sulfur dioxide, and most of the water vapor from combustion and fuel moisture. Carbon monoxide is the dominant emission formed primarily by smoldering combustion from which we also measure carbon dioxide, methane, ammonia, and ethane. A significant fraction of the total emissions is unoxidized pyrolysis products; examples are methanol, formaldehyde, acetic and formic acid, ethene (ethylene), ethyne (acetylene), and hydrogen cyanide. Relatively few previous data exist for many of these compounds and they are likely to have an important but as yet poorly understood role in plume chemistry. Large differences in emissions occur from different fire and fuel types, and the observed temporal behavior of the emissions is found to depend strongly on the fuel bed and product type

    Fully quantum mechanical dynamic analysis of single-photon transport in a single-mode waveguide coupled to a traveling-wave resonator

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    We analyze the dynamics of single photon transport in a single-mode waveguide coupled to a micro-optical resonator using a fully quantum mechanical model. We examine the propagation of a single-photon Gaussian packet through the system under various coupling conditions. We review the theory of single photon transport phenomena as applied to the system and we develop a discussion on the numerical technique we used to solve for dynamical behavior of the quantized field. To demonstrate our method and to establish robust single photon results, we study the process of adiabatically lowering or raising the energy of a single photon trapped in an optical resonator under active tuning of the resonator. We show that our fully quantum mechanical approach reproduces the semi-classical result in the appropriate limit and that the adiabatic invariant has the same form in each case. Finally, we explore the trapping of a single photon in a system of dynamically tuned, coupled optical cavities.Comment: 24 pages, 10 figure

    Moran Eigenvector Filtering of Multi-year Yield Data with Application to Zone Development

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    A time‐series of yield monitor data may be used to identify field areas of consistently low or high yield to serve as productivity zones for site‐specific crop management. However, transient factors that affect yield in 1 yr, but not every year, detract from this approach. The objective of this study was to illustrate Moran eigenvector spatial filtering (MESF) with results from analysis of multi‐year crop yield data from two farm fields in the United States. The MESF method accounts for temporal autocorrelation within a common factor map representing the correlation across years and partitions stochastic geographic variation into spatially structured and unstructured components. Crop rotation data were utilized from a dryland field in east‐central South Dakota and an irrigated field in southwestern Georgia. A random effects (RE) model was estimated that utilized eigenfunctions of a geographic connectivity matrix to account for spatially structured random effects (SSRE) and unstructured random effects (SURE) in standardized z scores of multi‐year crop yield. The MESF method was evaluated with conventional averaging of unfiltered yield data as a reference for comparison. In South Dakota, the SSRE accounted for 26% of the yield variance shared across years. Distinct patterns appeared to be related to changes in soil type and landscape position. The Georgia field yielded similar results. The MESF is effective for revealing structured variation in a time series of yield monitor data and may be useful for defining productivity zones within fields

    An Immersed Boundary method with divergence-free velocity interpolation and force spreading

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    The Immersed Boundary (IB) method is a mathematical framework for constructing robust numerical methods to study fluid-structure interaction in problems involving an elastic structure immersed in a viscous fluid. The IB formulation uses an Eulerian representation of the fluid and a Lagrangian representation of the structure. The Lagrangian and Eulerian frames are coupled by integral transforms with delta function kernels. The discretized IB equations use approximations to these transforms with regularized delta function kernels to interpolate the fluid velocity to the structure, and to spread structural forces to the fluid. It is well-known that the conventional IB method can suffer from poor volume conservation since the interpolated Lagrangian velocity field is not generally divergence-free, and so this can cause spurious volume changes. In practice, the lack of volume conservation is especially pronounced for cases where there are large pressure differences across thin structural boundaries. The aim of this paper is to greatly reduce the volume error of the IB method by introducing velocity-interpolation and force-spreading schemes with the properties that the interpolated velocity field in which the structure moves is at least C1 and satisfies a continuous divergence-free condition, and that the force-spreading operator is the adjoint of the velocity-interpolation operator. We confirm through numerical experiments in two and three spatial dimensions that this new IB method is able to achieve substantial improvement in volume conservation compared to other existing IB methods, at the expense of a modest increase in the computational cost. Further, the new method provides smoother Lagrangian forces (tractions) than traditional IB methods. The method presented here is restricted to periodic computational domains. Its generalization to non-periodic domains is important future work.Comment: 49 pages, 13 figure
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