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.     

数据管理:电子商务数据的存储问题

许多情况说明，用于组织中数据存储的消费已经成爆炸状态。产生这种情况的主要因素是电子邮件和电子商务对数据的质量和数量的要求提高了，并且这种数据大部分是分散的、非结构性的，这就增加了对组织中数据管理的要求。本文是在澳大利亚进行的一次调查的基础上做出的，该调查是关于组织中如何处理数据增长和由于数据增长所带来的问题。调查的结果显示人们对该问题表现出高度的关注，同时显示出一种乐观的趋势，即技术将对未来出现的各种各样的问题提供解决方案。     

The Impact of the Implementation of Technology Education on In-Service Teacher Education in South Africa (Impact of Technology Education in the RSA)

In this article the impact of technology education, as a new learning area (subject) in the curriculum, on in-service teacher education in South Africa is described in order to ascertain the extent of the impact. The research on which this article is based draws on a variety of experiences and observations in the field at grassroots level (in particular an outreach project in rural communities). The envisaged impact of technology education on South African schools, communities, teacher educators and teachers, the range of in-service teacher education that is required, and the impacts in urban and rural areas are discussed. Finally a number of concluding remarks are made about the extent of the impact of the inclusion of technology education in the new National Curriculum Statement and whether the situation has changed since the implementation of a pilot technology education project in 1998. This revised version was published online in July 2006 with corrections to the Cover Date.     

DURATION MOMENTS AND YIELD CURVE MOVEMENTS

In this paper we will analyze the relationship between the value and duration moments of a cash flow and movements in the yield curve. We will show that for changes in the yield curve which can be related to tⁿ , the 1st order changes in the net present value of a cash flow are linearly dependent on the n + lth duration moments, and that the 2nd order changes are dependent on the sum of duration moments of order 2 n + 1 and 2 n + 2. We will use this relationship to tilt tracking portfolios so as to protect them against specific changes in the yield curve.     

Labour-market reforms in transition economies

Several lessons can be drawn from the natural experiments ofcentral and eastern European countries with labour-market policies.Two of them are particularly relevant also for OECD countries.First, it is not wise to reduce the duration of unemploymentbenefits when the length of unemployment spells are on the rise,unless (I) unemployment is still low and there is the administrativecapacity to implement active labour-market policies on a widescale or (ii) there are income support schemes of the last resortin place and an administration capable of cost-effectively enforcingwork-tests for those falling off unemployment benefit compensationrolls. The second and perhaps more positive lesson in the lightof the above is that it is possible to transform institutionand create an efficient policy delivery mechanism within a shorttime span.     

Reform of European Merger Policy

The paper highlights the main drivers for merger policy reform in the European Union, including the consequences of the recent appeal court reverses. It discusses some of the substantive and procedural issues that the reform package should address, and outlines the reforms in progress. The author concludes that much of the reform package will be beneficial, but some important opportunities have been missed in this inevitably patchwork process.     

Disentangling the Dividend Information in Splits: A Decomposition Using Conditional Event-Study Methods

While folklore in finance holds that split valuation effectsare due to dividend increases associated with splits, littleis known about magnitudes of dividend and nondividend componentsof split announcement effects. We find that splits and dividendsare indeed informational substitutes, a notion we characterizemore precisely, but a significant portion of split valuationeffects, 46% according to our estimates, cannot be attributedto dividend information in splits. Our techniques extend theliterature on conditional event-study methods and we illustratetheir practical value in testing hypotheses and analyzing datanot amenable to analysis by standard procedures.