An Examination of the Interaction Between Modelling and Its Relationship with Construction Kits: Lessons from the Past and for the Future

Construction kits have played a significant part in nurturing the growth and development of the minds and manipulation-based skills of children (and adults) in formal and non-formal education settings. These kits have origins rooted in the representation of the built world and now have a diversity of form and function, including technical versions with moving parts. This article examines some of the historically based ideas that lie behind the role that kits may have in terms of physical modelling. The article traces the transformation of kits from simple bricks and blocks into more complicated pieces for space-filling and achieving the transfer of forces and motion. This transformation occurred during the Victorian era when the influence of the ideas of educationalists and, perhaps rather strangely, exponents of early aviation, played major roles in determining the diversity of forms of construction kit and modelled possibilities that are now to be seen in classrooms and homes. The article ends with a review of some of the lessons from the past and present that will need to be considered in relation to concrete modelling in schools for the future. This revised version was published online in July 2006 with corrections to the Cover Date.     

Asset market hangovers and economic growth: the OECD during 1984-93

Asses prices and investment were unusually weak throughout theindustrial world during the early 1990s. This paper highlightsthis stylized fact, and connects it with another: in most ofthe industrial world, asset markets boomed for several yearsbefore collapsing around 1989. The paper suggests that assetmarket bubbles during the late 1980s may have left the industrialworld with an 'asset market hangover' in the early 1990s, inthe form of sluggish asset markets and investment. Empiricalsupport for this hypothesis is provided based on cross-countrydata for equity and real estate markets in most industrial countries.We suggest that financial market developments not justifiedby fundamentals can substantially affect real activity.     

Trade, foreign firms and economic policy in Indonesian and Thai manufacturing

This paper first examines the rapid growth and changing composition of manufactured exports in Indonesia and Thailand, highlighting the rapid growth of office and computer machinery and electric machinery, somewhat slower growth of non-electric and transportation machinery, as well as the low growth of previously large exports of textiles apparel. Second, the important contributions of foreign multinational enterprises (MNEs) to export growth in the machinery industries, particularly in electric, office, and computing machinery, are documented. Third, the paper describes trade policies in all these industries in some detail, emphasizing how low protection was a key facilitator of rapid export growth in the MNEs that dominated the electric, office, and computing machinery industry, while high protection reduced incentives to export among MNEs in the transportation machinery industry.     

European Sugar Policy Reform and Agricultural Innovation

In July 2006, the European Union's (EU) Common Market Organization (CMO) for sugar underwent the first radical reform since its establishment in 1968. In this article, we study the incentives for adoption of new technologies before and after the policy reform. We build a stochastic partial equilibrium model and use it to analyze the effect of the policy reform on the adoption incentives of genetically modified herbicide tolerant sugar beet. Our findings show that the adoption incentives of high‐cost sugar beet farmers are significantly reduced under the new CMO. Medium‐cost producers, in contrast, have greater incentives to adopt new technologies, while low‐cost producers are largely left unaffected. The reduced adoption incentives of high‐cost farmers lead to lower flexibility and competitiveness of these farmers and therefore coincides with the goals of the reform to crowd out high‐cost producers and increase competitiveness of the European sugar market. En juillet 2006, l'Organisation commune du marché (OCM) du sucre a subi sa première réforme radicale depuis sa mise en place par l'UE en 1968. Dans la présente étude, nous avons examiné les incitatifs offerts pour l'adoption de nouvelles technologies, avant et après la réforme. Nous avons élaboré un modèle stochastique d'équilibre partiel et l'avons utilisé pour analyser les répercussions de la réforme sur les incitatifs offerts pour l'adoption de variétés de betteraves sucrières génétiquement modifiées résistantes aux herbicides. Selon nos résultats, les incitatifs offerts aux producteurs de betterave sucrière ayant des coûts marginaux élevés ont significativement diminué depuis la réforme de l'OCM du sucre. Par contre, les incitatifs offerts aux producteurs ayant des coûts marginaux moyens se sont accrus, tandis que ceux offerts aux producteurs ayant de faibles coûts marginaux n'ont pas changé. La diminution des incitatifs offerts aux producteurs ayant des coûts marginaux élevés entraîne une diminution de la souplesse et de la capacité concurrentielle de ces producteurs et, par conséquent, coïncide avec les objectifs de la réforme qui visent àévincer les producteurs ayant des coûts marginaux élevés et à accroître la capacité concurrentielle du marché européen du sucre.     

VAR,ERROR CORRECTION AND PRETEST FORECASTS AT LONG HORIZONS

This paper focuses on the construction of forecasts over long horizons where a typical long-horizon forecast might span four years using 20 to 40 years’ data. It is argued that the presence of persistence in the form of unit or near-unit autoregressive roots poses substantial difficulties for long-horizon interval and point forecasting. These difficulties may not be overcome even by efficient pre-testing or model-selection procedures and might, in general, lead to point forecasts with large asymptotic root mean squared errors and undesirably wide prediction intervals.