1,149 research outputs found
Quantitative value chain analysis : an application to Malawi
The Government of Malawi has since 2005 been pursuing a growth strategy mainly based on increasing the volume of agricultural exports. This entails that Malawi should endeavor to improve the competitiveness of its agricultural commodities so as to gain an increasing share of the regional and international markets. This paper analyzes the competitiveness of the country's key agricultural commodities -- tobacco, maize, cotton, and rice -- using prices that prevailed in the 2007/08 agricultural season. The paper employs a quantitative value chain methodology to assess the country's prospects for competitiveness and suggest weak links along the value chain that require attention in order to improve trade competitiveness. The results indicate that Malawi has some competitive advantage in the production and exportation of tobacco and cotton, and that this mostly derives from its low labor cost advantage. However, the results indicate that based on 2007/08 prices and costs, Malawi does not have competitive edge in maize and rice production for export. As such, Malawi would better pursue an import substitution strategy in these cereals, and perhaps only aim at the export market when regional market opportunities arise. Key factors that underpin Malawi's narrow competitiveness include the high cost of inorganic fertilizer and other inputs, low productivity, and the higher trader margins and intermediation costs along the value chains. Furthermore, farm gate prices in Malawi are higher than in other countries, and this undercuts its trade competitiveness.Transport Economics Policy&Planning,Crops&Crop Management Systems,Economic Theory&Research,Markets and Market Access,Climate Change and Agriculture
Nondecaying Hydrodynamic Interactions along Narrow Channels.
Particle-particle interactions are of paramount importance in every multibody system as they determine the collective behavior and coupling strength. Many well-known interactions such as electrostatic, van der Waals, or screened Coulomb interactions, decay exponentially or with negative powers of the particle spacing r. Similarly, hydrodynamic interactions between particles undergoing Brownian motion decay as 1/r in bulk, and are assumed to decay in small channels. Such interactions are ubiquitous in biological and technological systems. Here we confine two particles undergoing Brownian motion in narrow, microfluidic channels and study their coupling through hydrodynamic interactions. Our experiments show that the hydrodynamic particle-particle interactions are distance independent in these channels. This finding is of fundamental importance for the interpretation of experiments where dense mixtures of particles or molecules diffuse through finite length, water-filled channels or pore networks.U.F.K. was supported by an ERC starting grant (PassMembrane 261101). S.P. acknowledges funding from a Leverhulme Early Career Fellowship. K.M. was supported by a grant from the EPSRC. E.L. was supported by Marie Curie CIG grant from EU.This is the author accepted manuscript. The final version is available from APS via http://dx.doi.org/10.1103/PhysRevLett.115.03830
Insecticidal effects of deltamethrin in laboratory and field populations of Culicoides species: how effective are host-contact reduction methods in India?
BACKGROUND: Bluetongue virus (BTV) is transmitted by Culicoides biting midges and causes bluetongue (BT), a clinical disease observed primarily in sheep. BT has a detrimental effect on subsistence farmers in India, where hyperendemic outbreaks impact on smallholdings in the southern states of the country. In this study, we establish a reliable method for testing the toxic effects of deltamethrin on Culicoides and then compare deltamethrin with traditional control methods used by farmers in India. RESULTS: Effects of deltamethrin were initially tested using a colonised strain of Culicoides nubeculosus Meigen and a modified World Health Organisation exposure assay. This method was then applied to field populations of Culicoides spp. in India. The field population of C. oxystoma in India had a greater LC50 (0.012 ± 0.009%) for deltamethrin than laboratory-reared C.nubeculosus (0.0013 ± 0.0002%). Exposure of C. nubeculosus to deltamethrin at higher ambient temperatures resulted in greater rates of knockdown but a lower mortality rate at 24 h post-exposure. Behavioural assays with C. nubeculosus in WHO tubes provided evidence for contact irritancy and spatial repellence caused by deltamethrin. The field experiments in India, however, provided no evidence for repellent or toxic effects of deltamethrin. Traditional methods such as the application of neem oil and burning of neem leaves also provided no protection. CONCLUSIONS: Our study demonstrates that field-collected Culicoides in India are less susceptible to deltamethrin exposure than laboratory-bred C. nubeculosus and traditional methods of insect control do not provide protection to sheep. These low levels of susceptibility to deltamethrin have not been recorded before in field populations of Culicoides and suggest resistance to synthetic pyrethrioids. Alternative insect control methods, in addition to vaccination, may be needed to protect Indian livestock from BTV transmission
Redbird Buzz Episode 17: Tom Keyser, Feburary 6, 2023
Interview with Tom Keyser, the founding dean for Illinois State University\u27s College of Engineering. The interview was conducted by John Twork from University Marketing and Communications on February 6, 2023, for the Illinois State University Redbird Buzz podcast
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