Alternative syntheses of linear polyurethanes using masked isocyanate monomers

A range of linear polyurethanes featuring aliphatic, aromatic and ether residues have been prepared by co-polymerisation of novel 'masked' isocyanate A(2)-type monomers and diols. The reactive isocyanate monomers were generated in situ via the triphenylphosphine mediated decomposition of the heterocyclic disulfide, 1,2,4-dithiazolidine-3,5-dione. Two different synthetic approaches were examined and assessed for the construction of the novel A(2)-type monomers, which involved either coupling two 1,2,4-dithiazolidine-3,5-diones together through a spacer group or construction of 1,2,4-dithiazolidine-3,5-diones directly from diamines. The resulting polyurethanes were purified via solvent extraction and analysed using GPC, NMR and IR spectroscopic analyses. Molecular weight data were obtained and compared from both GPC and H-1 NMR (via end-group analysis) spectroscopic analysis. The thermal properties of the polyurethanes were determined using DSC and their solubility in common aprotic organic solvents was also assessed and related to their structural composition. (c) 2006 Elsevier B.V. All rights reserved.

Economic assessment of bovine tuberculosis and alternative policies

Break-even analyses of the costs and benefits of six alternative bovine tuberculosis (bTB) control strategies were undertaken. The results show that some strategies, such as zoning, would require relatively small reductions in bTB incidence as a result to be cost effective, whilst for others, such as proactive badger removal, the costs would require a substantial and relatively rapid reduction in bTB incidence to be worthwhile.

The CAP and EU enlargement: Prospects for an alternative strategy to avoid the lock-in of CAP support

The integration of the central and east European countries (CEECs) into the Common Agricultural Policy (CAP) could become a major problem. At the Copenhagen European summit in December 2002, the EU agreed a transitional period with a gradual phasing in of direct payments. However, this strategy will not solve the problems of the CAP: budgetary limits remain problematic, the policy ignores possible developments in the World Trade Organization (WTO), and the extension of direct payments to the CEECs will further capitalize, and hence lock-in, agricultural support. The latter makes future reform even more difficult and, to overcome these problems, we suggest an alternative strategy to integrate the CEECs into the CAP. The EU should phase out direct payments by applying a bond scheme. Finally, we consider whether this option is politically viable.

Estimating technical efficiency of Australian dairy farms using alternative frontier methodologies

Technical efficiency is estimated and examined for a cross-section of Australian dairy farms using various frontier methodologies; Bayesian and Classical stochastic frontiers, and Data Envelopment Analysis. The results indicate technical inefficiency is present in the sample data. Also identified are statistical differences between the point estimates of technical efficiency generated by the various methodologies. However, the rank of farm level technical efficiency is statistically invariant to the estimation technique employed. Finally, when confidence/credible intervals of technical efficiency are compared significant overlap is found for many of the farms' intervals for all frontier methods employed. The results indicate that the choice of estimation methodology may matter, but the explanatory power of all frontier methods is significantly weaker when interval estimate of technical efficiency is examined.

Are alternative livelihood projects alleviating poverty in mining communities? Experiences from Ghana

This paper critiques the approach being taken in Ghana to implement Alternative Livelihood (AL) projects in mining communities. The rapid insurgence of illegal artisanal gold mining has forced policymakers to think more creatively about ways in which to deal with mounting unemployment in the country's rural areas. Most of the economic activities being promoted, however, have proved highly unpopular with target groups. The adopted policy approaches reflect how little in tune the organisations championing AL activities are with the mindsets and ambitions of rural populations.