Evidence and Implications of Zipf’s Law for Integrated Economies

This paper considers the distribution of output and productive factors among members of a fully integrated economy (FIE). We demonstrate that each member’s shares of total output and of total factors will be equal. This implies that growth in shares is random. If output andfactor shares evolve as reflective geometric Brownian motion, then limiting distribution of these shares will exhibit Zipf’s law. Our empirics support Zipf’s law for U.S. states and for E.U. countries. These findings imply that models characterizing growth of members within an FIE should embody a key assumption: growth process of shares is random and homogeneous.growth, economic integration, factor price equalization, Zipf’s law

Factor Mobility and the Distribution of Economic Activity in Integrated Economies: Evidence and Implications

This study examines empirically factor mobility and distribution of economic activity under economic integration, with the result that the benchmark of the equal-share relationship holds strongly for US states and less so for EU countries, but does not hold for Developing Countries or the World. Recent research (Bowen, Munandar and Viaene, 2005) shows that for a country who is a member of a fully integrated economy, its shares of the integrated economy's total output and stocks of productive factors (i.e., physical and human capital) will be equal. They label this result the equal-share relationship. In this paper, we empirically examine for evidence of the equal-share relationship for alternative economic groups (i.e., US states, EU countries, Developing Countries and a World comprising 55 countries). Our findings indicate that the equal-share relationship holds strongly for US states, less so for EU countries, but does not hold for Developing Countries or the World.Distribution of products, economic growth, economic convergence, factor mobility, economic integration, factor mobility and the distribution of economic activity in integrated economies, evidence and implications

Morphological and molecular characterisation of Scutellonema species from yam (Dioscorea spp.) and a key to the species of the genus

The yam nematode, Scutellonema bradys, is a major threat to yam (Dioscorea spp.) production across yam-growing regions. In West Africa, this species cohabits with many morphologically similar congeners and, consequently, its accurate diagnosis is essential for control and for monitoring its movement. In the present study, 46 Scutellonema populations collected from yam rhizosphere and yam tubers in different agro-ecological zones in Ghana and Nigeria were characterised by their morphological features and by sequencing of the D2-D3 region of the 28S rDNA gene and the mitochondrial COI genes. Molecular phylogeny, molecular species delimitation and morphology revealed S. bradys, S. cavenessi, S. clathricaudatum and three undescribed species from yam rhizosphere. Only S. bradys was identified from yam tuber tissue, however. For barcoding and identifying Scutellonema spp., the most suitable marker used was the COI gene. Additionally, 99 new Scutellonema sequences were generated using populations obtained also from banana, carrot, maize and tomato, including the first for S. paralabiatum and S. clathricaudatum, enabling the development of a dichotomous key for identification of Scutellonema spp. The implications of these results are discussed

Datamanagement at Flanders Hydraulics Research

Flanders Hydraulics Research is a research centre of the Flemish Government. The centre provides consultancy services dealing with hydraulics, hydrology and nautical aspects to national and international public or private organisations. Within Flanders Hydraulics Research the Hydrological Information Centre (HIC) is a research group which provides scientific support for water level management on navigable waterways in Flanders. To achieve this, the HIC cooperates actively with the actual managers of these waterways and with other institutions involved in ground water, surface water and sediments. An efficient functioning of the HIC requires powerful tools to load, store and validate data and to make them accessible for all users. For these purposes an application named HYDRA was developed. This article focuses on the setup, the use and the planned evolution of the application