2,560 research outputs found
Drivers of Demand for Imported Horticultural Commodities: A Cross-Country Comparison
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
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
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+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 and for the primary and secondary, respectively, but have
different temperatures ( and
). The primary () is less massive than
the secondary (), suggesting mass exchange. The mass estimates
are confirmed by the orbital analysis. The revisited orbital period is
. 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
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
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
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 > 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 < 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.
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
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
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
- …