4,563 research outputs found

    Seed aid for seed security: advice for practitioners

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    Analysis of bean seed channels in the Great Lakes region : South Kivu, Zaire, Southern Rwanda, and select bean-growing zones of Burundi

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    Emergency seed aid in Kenya: some case study insights on lessons learned during the 1990s

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    This article reviews the effectiveness of seed–aid distributions in Kenya during the 1990s. It analyses the internal process and effects, i.e. the performance of the aid itself as well as the external process and effects, i.e. how seed–aid intervention affected farmers’ broader agricultural management strategies. During the drought emergency of 1997, Kenyan farmers favourably judged many of the immediate seed–aid features such as crop and variety appropriateness and seed quality — even through the overarching goals of the seed assistance were muddled, ranging from assistance to the poor, to generalised gift–giving to stimulating progressive farming practice. However, the longer term analyses, drawn from recollections of a decade of relief activity, showed no concrete evidence that seed aid, per se, had strengthened their farming systems, nor that those who have received it once were less likely to receive it again. Thus, while seed aid has been promoted to lessen the effects of an ‘acute’ stress, drought, Kenyan farmers, in practice, have been experiencing much wider, ‘chronic’ seed system problems. This article ends by exploring this distinction between acute and chronic seed system stress and suggests a range of interventions appropriate to each

    Bridging the gap: rewritable electronics using real-time light-induced dielectrophoresis on lithium niobate

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    In the context of micro-electronics, the real-time manipulation and placement of components using optics alone promises a route towards increasingly dynamic systems, where the geometry and function of the device is not fixed at the point of fabrication. Here, we demonstrate physically reconfigurable circuitry through light-induced dielectrophoresis on lithium niobate. Using virtual electrodes, patterned by light, to trap, move, and chain individual micro-solder-beads in real-time via dielectrophoresis, we demonstrate rewritable electrical contacts which can make electrical connections between surface-bound components. The completed micro-solder-bead bridges were found to have relatively low resistances that were not solely dominated by the number of interfaces, or the number of discrete beads, in the connection. Significantly, these connections are formed without any melting/fusing of the beads, a key feature of this technique that enables reconfigurability. Requiring only a low-power (~3.5 mW) laser source to activate, and without the need for external power supply or signal generation, the all-optical simplicity of virtual-electrodes may prove significant for the future development of reconfigurable electronic systems

    Purine metabolism in cultured endothelial cells

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    Understanding and strengthening informal seed markets

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    Informal markets receive little attention from governments and researchers, despite their centrality to farmers' seed security. This paper documents the importance of informal markets for supplying seed and restocking critical plant genetic resources in normal and stress periods. It analyses farmers' rationales for using such markets and their strategic actions in selecting out seed from grain. Conceptual aids for differentiating among market goods - grain, 'implicit seed' and seed - are presented, including tracing of agro-ecological seed sources, traders' seed management behaviour and seed/grain price patterns. Ethiopian case material gives rare insight into how different scales of traders manage the seed/grain divide. Better understanding of informal markets is an important precursor to strengthening them as such markets have unrealized potential to deliver more and higher quality seed, and a greater range of modern and local varieties. Support for informal seed markets could usefully feature in rural livelihood and social protection programmes, but this will require basic shifts in interventions and further refinements in market analysis

    Understanding seed systems and strengthening seed security

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    This paper provides background information on seed systems and seed relief interventions for participants at the Workshop on Effective and Sustainable Seed Relief Activities, Rome, 26–28 May 2003. In this paper we review the rationale for and goals of seed aid (section II) and provide an overview of seed systems, with particular attention to the “local” or “informal” seed system that provides most farmers with seeds most of the time (section III). In section IV, the parameters of seed security are discussed, including the distinctions between availability, access, and utilization (or quality) attributes. Acute and chronic emergency situations are also described. In section V, lessons learned from experience in the field, particularly in Africa, are summarized and discussed, and in section VI, current response options are described and compared, focusing in particular on direct seed distribution and seed fairs and vouchers. Finally, some major challenges for moving ahead are considered in section VII

    Seed systems smallholder farmers use

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    Seed can be an important entry point for promoting productivity, nutrition and resilience among smallholder farmers. While investments have primarily focused on strengthening the formal sector, this article documents the degree to which the informal sector remains the core for seed acquisition, especially in Africa. Conclusions drawn from a uniquely comprehensive data set, 9660 observations across six countries and covering 40 crops, show that farmers access 90.2 % of their seed from informal systems with 50.9 % of that deriving from local markets. Further, 55 % of seed is paid for by cash, indicating that smallholders are already making important investments in this arena. Targeted interventions are proposed for rendering formal and informal seed sector more smallholder-responsive and for scaling up positive impacts

    Technical and institutional issues in participatory plant breeding-done from a perspective of farmer plant breeding

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