The Agricultural Technology Improvement Project (ATIP) has been conducting on-farm research in Botswana with the goal of identifying improved arable production technologies. In an effort to increase the role of farmers in technology design and assessment, ATIP set up farmer groups that meet on a regular basis to discuss farming problems and on-farm trials. This article reviews and evaluates ATIP's experiences with farmer groups. A typology of technology development groups is proposed and group management issues are discussed.

This work describes the study of the surface reduction of ceria zirconia mixed oxides (CeZrO) as either thin films or powders, both with and without Pt present. XPS was used to measure the composition of the surface and the oxidation states of all metals contained within the material. The thin films of CeZrO showed little reactivity towards the reducing conditions used. Grazing incidence angle XRD showed the presence of Ce0.75Zr0.25O2. The thin films prepared with Pt showed that surface reduction of Ce4+ occurred under reducing conditions. The size of the Pt clusters was also determined from the data. The Pt was found to always exist in the metallic state. The Zr4+ was not seen to change during all treatments. For the powder samples the Ce4+ was readily reduced to approximately 60%. Pt was found to be initially oxidised with the % of metallic Pt increasing with reduction temperature. Again no change in the Zr was observed.

The observational evidence leading to the classification, following Oosterhoff, of globular clusters containing RR Lyrae stars into two distinct groups, is summarized and discussed in the light of results of stellar evolution theory and pulsation theory. The dichotomy is caused, at least in part, by a dichotomy in the ‘transition period’ between the type-ab and type-c stars which reflects a difference in effective temperature at the transition point. When this difference is accounted for, there remains a smaller average difference between the groups, though no longer a clear dichotomy, that is probably a mass and luminosity effect. If this remaining difference is interpreted as a luminosity effect the average difference in luminosity between the two Oosterhoff groups is at most 0.1 mag. It is suggested that Christy’s theoretical relationship between transition period and luminosity cannot be valid, at least not for clusters of different Oosterhoff groups. It is conjectured that the transition-temperature dichotomy may be a reflection of different predominant directions of evolution along the horizontal branch, accompanied by a hysteresis effect in the pulsations.

During the War of American Independence, the Treasury Board contracted for a wide range of army supplies. Opposition, both in parliament and the press, persistendy criticized the methods employed in the allocation of contracts. It was widely believed that contracts were awarded in the interests of ministerial influence, not public economy; contractors were the friends of government and enjoyed excessive profits. The most frequendy proposed alternative was to contract through public advertisement and accept the lowest tender received. This method was normally referred to as open contracting. Isaac Barre was the main opposition spokesman on matters relating to army supplies and it was his view, expressed in the House during April 1778, that ‘contracts ought to be open, and offered to the lowest bidder'. Government spokesmen and contractors sitting in the House regularly countered this argument with the assertion that open contracts’ would be prejudicial to the public service. Men inadequate to the accomplishment of the contracts, would at all times bid lower than men of ability and reputation, and they would do much more injury by serving the public badly, than the difference of expense. 'Although neither Lord North nor John Robinson, the Treasury Secretary mainly responsible for contract business, were fully satisfied with existing contract methods, they sought economies within those methods and even the Shelburne ministry, when it radically altered the contracting system for supplying the army in America in 1782, decided against the open contracts championed by friends of Shelburne when in opposition.