Nanoscale Magnetic Domains in Mesoscopic Magnets

The basic magnetic properties of three-dimensional nanostructured materials can be drastically different from those of a continuous film. High-resolution magnetic force microscopy studies of magnetic submicrometer-sized cobalt dots with geometrical dimensions comparable to the width of magnetic domains reveal a variety of intricate domain patterns controlled by the details of the dot geometry. By changing the thickness of the dots, the width of the geometrically constrained magnetic domains can be tuned. Concentric rings and spirals with vortex configurations have been stabilized, with particular incidence in the magnetization reversal process as observed in the ensemble-averaged hysteresis loops.     

Costing the ex situ conservation of plant genetic resources at AVRDC – The World Vegetable Center

AVRDC – The World Vegetable Center maintains the world’s largest international public collection of vegetable genetic resources at its headquarters in Taiwan. The ex situ conservation and dissemination of germplasm to researchers and breeders worldwide contributes to global food and nutrition security but also carries considerable costs. The objective of this study is to quantify these costs for the 12-month period from September 2011 to August 2012 using the Decision Support Tool developed by the International Food Policy Research Institute. The results show that the present value of capital assets is USD 1.99 million for the facilities and USD 0.48 million for the equipment. The total annual cost is USD 0.684 million, of which 74 % are labor costs. The average conservation and dissemination cost per accession is USD 10.08 per year. Seed regeneration, seed processing, characterization, and seed dissemination are the four most costly operations of the genebank. The storage itself only contributes 17 % of the cost. In comparison, the average cost per accession is USD 5.15 at ICARDA, USD 6.84 at CIMMYT, USD 8.62 at ICRISAT, USD 9.19 at IRRI, and USD 22.52 at CIAT (in 2012 US dollar values). High labor costs in Taiwan increase AVRDC’s average cost, but the fact that more vegetable species are self-pollinating and thus less labor intensive to regenerate than cross-pollinating species keeps the average costs in check. These results are important benchmarks for other genebanks.