2,560 research outputs found

    Drivers of Demand for Imported Horticultural Commodities: A Cross-Country Comparison

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    International trade of horticultural commodities is increasingly important in many regions of the world, yet relatively little research has studied import patterns of key horticultural crops. Using data between 1991 and 2005, we find that import demand for horticultural commodities in developed countries has been driven primarily by prices and the level of trade openness while income and diet considerations were more important in emerging countries. Furthermore, our results show that the determinants of import demand differed across the selected crops, and therefore information can be lost if data for horticultural commodities are aggregated.Emerging markets, Horticultural commodities, Import demand, International trade, International Relations/Trade, Marketing, Q10, Q13, Q17,

    Import Demand for Horticultural Commodities in Developed and Emerging Countries

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    International trade of horticultural commodities is increasingly important in many regions of the world, yet import patterns of key horticultural crops are understudied in the agricultural economics literature. Using data between 1991 and 2005, we estimate the drivers of per capita import demand for six of the most highly traded horticultural commodities. The own price elasticity estimates were negative in all import demand models and, in most cases, the effects were statistically stronger for importers in emerging countries. Import demand for horticultural commodities in developed countries has been driven primarily by prices and the level of trade openness while income and diet considerations were more important in emerging countries. Furthermore, our results show that the determinants of import demand differed across the six models, and therefore, information can be lost when data for horticultural commodities are aggregated.Emerging markets, Horticultural commodities, Import demand, International trade, Agricultural and Food Policy, International Relations/Trade, Q17,

    A low-metallicity massive contact binary undergoing slow Case A mass transfer: A detailed spectroscopic and orbital analysis of SSN 7 in NGC 346 in the SMC

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    Most massive stars are believed to be born in close binary systems where they can exchange mass, which impacts the evolution of both binary components. Their evolution is of great interest in the search for the progenitors of gravitational waves. However, there are unknowns in the physics of mass transfer as observational examples are rare, especially at low metallicity. Nearby low-metallicity environments are particularly interesting hunting grounds for interacting systems as they act as the closest proxy for the early universe where we can resolve individual stars. Using multi-epoch spectroscopic data, we complete a consistent spectral and orbital analysis of the early-type massive binary SSN 7 hosting a ON If^\ast+O5.5 V((f)) star. Using these detailed results, we constrain an evolutionary scenario that can help us to understand binary evolution in low metallicity. We were able to derive reliable radial velocities of the two components from the multi-epoch data, which were used to constrain the orbital parameters. The spectroscopic data covers the UV, optical, and near-IR, allowing a consistent analysis with the stellar atmosphere code, PoWR. Given the stellar and orbital parameters, we interpreted the results using binary evolutionary models. The two stars in the system have comparable luminosities of log(L1/L)=5.75{\log (L_1/L_{\odot}) = 5.75} and log(L2/L)=5.78{\log (L_2/L_{\odot}) = 5.78} for the primary and secondary, respectively, but have different temperatures (T1=43.6kK{T_1=43.6\,\mathrm{kK}} and T2=38.7kK{T_2=38.7\,\mathrm{kK}}). The primary (32M32\,M_{\odot}) is less massive than the secondary (55M55\,M_{\odot}), suggesting mass exchange. The mass estimates are confirmed by the orbital analysis. The revisited orbital period is 3d3\,\mathrm{d}. Our evolutionary models also predict mass exchange. Currently, the system is a contact binary undergoing a slow Case A phase, making it the most massive [Abridged]Comment: 20 page

    Magnetic Flux Braiding: Force-Free Equilibria and Current Sheets

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    We use a numerical nonlinear multigrid magnetic relaxation technique to investigate the generation of current sheets in three-dimensional magnetic flux braiding experiments. We are able to catalogue the relaxed nonlinear force-free equilibria resulting from the application of deformations to an initially undisturbed region of plasma containing a uniform, vertical magnetic field. The deformations are manifested by imposing motions on the bounding planes to which the magnetic field is anchored. Once imposed the new distribution of magnetic footpoints are then taken to be fixed, so that the rest of the plasma must then relax to a new equilibrium configuration. For the class of footpoint motions we have examined, we find that singular and nonsingular equilibria can be generated. By singular we mean that within the limits imposed by numerical resolution we find that there is no convergence to a well-defined equilibrium as the number of grid points in the numerical domain is increased. These singular equilibria contain current "sheets" of ever-increasing current intensity and decreasing width; they occur when the footpoint motions exceed a certain threshold, and must include both twist and shear to be effective. On the basis of these results we contend that flux braiding will indeed result in significant current generation. We discuss the implications of our results for coronal heating.Comment: 13 pages, 12 figure

    Import Demand for Horticultural Commodities in Developed and Emerging Countries

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    WP 2008-24 December 2008JEL Classification Codes: Q17International trade of horticultural commodities is increasingly important in many regions of the world, yet import patterns of key horticultural crops are understudied in the agricultural economics literature. Using data between 1991 and 2005, we estimate the drivers of per capita import demand for six of the most highly traded horticultural commodities. The own price elasticity estimates were negative in all import demand models and, in most cases, the effects were statistically stronger for importers in emerging countries. Import demand for horticultural commodities in developed countries has been driven primarily by prices and the level of trade openness while income and diet considerations were more important in emerging countries. Furthermore, our results show that the determinants of import demand differed across the six models, and therefore, information can be lost when data for horticultural commodities are aggregated

    The atmospheric impacts of monoterpene ozonolysis on global stabilised Criegee intermediate budgets and SO2 oxidation : experiment, theory and modelling

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    The gas-phase reaction of alkenes with ozone is known to produce stabilised Criegee intermediates (SCIs). These biradical/zwitterionic species have the potential to act as atmospheric oxidants for trace pollutants such as SO<sub>2</sub>, enhancing the formation of sulfate aerosol with impacts on air quality and health, radiative transfer and climate. However, the importance of this chemistry is uncertain as a consequence of limited understanding of the abundance and atmospheric fate of SCIs. In this work we apply experimental, theoretical and numerical modelling methods to quantify the atmospheric impacts, abundance and fate of the structurally diverse SCIs derived from the ozonolysis of monoterpenes, the second most abundant group of unsaturated hydrocarbons in the atmosphere. We have investigated the removal of SO<sub>2</sub> by SCIs formed from the ozonolysis of three atmospherically important monoterpenes (<i>α</i>-pinene, <i>β</i>-pinene and limonene) in the presence of varying amounts of water vapour in large-scale simulation chamber experiments that are representative of boundary layer conditions. The SO<sub>2</sub> removal displays a clear dependence on water vapour concentration, but this dependence is not linear across the range of [H<sub>2</sub>O] explored. At low [H<sub>2</sub>O] a strong dependence of SO<sub>2</sub> removal on [H<sub>2</sub>O] is observed, while at higher [H<sub>2</sub>O] this dependence becomes much weaker. This is interpreted as being caused by the production of a variety of structurally (and hence chemically) different SCIs in each of the systems studied, which displayed different rates of reaction with water and of unimolecular rearrangement or decomposition. The determined rate constants, <i>k</i>(SCI+H<sub>2</sub>O), for those SCIs that react primarily with H<sub>2</sub>O range from 4 to 310  ×  10<sup>−15</sup> cm<sup>3</sup> s<sup>−1</sup>. For those SCIs that predominantly react unimolecularly, determined rates range from 130 to 240 s<sup>−1</sup>. These values are in line with previous results for the (analogous) stereo-specific SCI system of <i>syn</i>-/<i>anti</i>-CH<sub>3</sub>CHOO. The experimental results are interpreted through theoretical studies of the SCI unimolecular reactions and bimolecular reactions with H<sub>2</sub>O, characterised for <i>α</i>-pinene and <i>β</i>-pinene at the M06-2X/aug-cc-pVTZ level of theory. The theoretically derived rates agree with the experimental results within the uncertainties. A global modelling study, applying the experimental results within the GEOS-Chem chemical transport model, suggests that &gt; 97 % of the total monoterpene-derived global SCI burden is comprised of SCIs with a structure that determines that they react slowly with water and that their atmospheric fate is dominated by unimolecular reactions. Seasonally averaged boundary layer concentrations of monoterpene-derived SCIs reach up to 1.4  ×  10<sup>4</sup> cm<sup>−3</sup> in regions of elevated monoterpene emissions in the tropics. Reactions of monoterpene-derived SCIs with SO<sub>2</sub> account for &lt; 1 % globally but may account for up to 60 % of the gas-phase SO<sub>2</sub> removal over areas of tropical forests, with significant localised impacts on the formation of sulfate aerosol and hence the lifetime and distribution of SO<sub>2</sub>

    A randomised crossover trial investigating actual and perceived changes in peak knee extensor torque following Kinesio Tape® application.

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    Also presented by E. Walsh as a "Rapid 5" presentation at the conferenceAbstract: Background: The application and use of Kinesio tape® (KT) has become increasingly popular over the last decade. Previous studies investigating the effect of KT on strength at the knee have provided inconclusive results, and have highlighted the potential for KT to have a placebo effect. Aim: The primary aim investigated the correlation between actual and perceived change in peak knee extensor torque following KT application. The secondary aim sought to determine the extent to which KT improves peak knee extensor torque. Methods: A randomised crossover, placebo controlled design was used. A convenience sample of 36 healthy adults between 18-30 years of age were recruited via email. The three conditions investigated included no tape, acting as a baseline measure, followed by KT and sham tape in a randomised order. Outcome measures included the isokinetic dynamometer to measure peak knee extensor torque at 180°/s and the Global Rating of Change Scale (GRCS) to measure participants’ perception of strength. Results/Findings: No significant correlation was identified between actual and perceived peak knee extensor torque following KT application (P = 0.408). The majority of participants (56%) perceived their strength to have improved following KT. The secondary aim found a significant decrease in peak knee extensor torque after KT compared to no tape (P = 0.005), with no statistical difference when KT was compared to sham tape (P = 0.975). Conclusion: The findings of this study indicate that there is no relationship between participants’ actual strength and their perception of strength following the application of KT. The results of this study do not support the use of KT to improve peak knee extensor torque

    Examining consumer response to commodity-specific and broad-based promotion programs for fruits and vegetables using experimental economics

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    WP 2010-12 July 2010JEL Classification Codes: M37; Q13Generic promotion and advertising activities have traditionally been used to promote individual agricultural commodities. However, there is renewed interest in implementing a mandatory ?broad-based? promotion program for all fruits and vegetables, and this idea is highly controversial among those in the horticultural industry. Here we use data from an experiment that introduces subjects to various promotional efforts for fruits and vegetables to estimate the direct and indirect effects of advertising. Econometric results indicate that commodity-specific promotional efforts may be less effective at increasing demand for fruits and vegetables than earlier studies have suggested, yet such campaigns do appear to have a significant clockwise rotational effect on the demand for fruits and vegetables. Broad-based advertising does have a direct effect on the demand for fruits and vegetables, and after controlling for various demographic differences between treatments our results show that average willingness-to-pay for fruits and vegetables was 41% higher among subjects in the broad-based group compared to the control group

    Exploring the Global Health and Defence Engagement Interface

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    Militaries have an important and inevitable role in global health and will interface with existing health systems on deployments. Whilst the primary concern of militaries is not global health, there are clear, and increasingly frequent, circumstances when global health activities align with the interests of defence. Recognising this link between global health and security warrants thoughtful consideration and action where concerns affecting both intersect. In addition to providing medical support to military personnel on operations, advantageous effects can be achieved directly from military medical activities as part of Defence Engagement. Whilst there are limitations and ethical boundaries to the role of militaries in global health, further training, research and conceptual development are warranted to optimise military medical activity at the intersection of security and global health to deliver advantageous effects. This paper forms part of a special issue of BMJ Military Health dedicated to Defence Engagement
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