Sectoral energy- and labour-productivity convergence

This paper provides an empirical analysis of convergence patterns for energy- and labour-productivity developments at a detailed sectoral level for 14 OECD countries, covering the period 1970-1997. Cross-country differences of energy-productivity levels are shown to be substantially larger than cross-country differences of labour-productivity levels at all levels of sectoral aggregation. A s-convergence analysis shows that the development of cross-country variation in productivity performance depends on the level of aggregation. Both patterns of international productivity convergence and divergence exist across sectors. Using a panel-data approach, we find in most sectors energy productivity to grow relatively fast in countries with relatively low initial productivity levels, while in several sectors this is also true for labour productivity. This evidence of ß-convergence supports the hypothesis that lagging countries tend to catch up with technological leaders, in particular in terms of energy productivity. Moreover, the results show that convergence is conditional rather than unconditional, meaning that productivity levels converge to country-specific steady states. Searching for the fundamentals determining cross-country productivity differentials reveals a positive productivity effect of energy prices and economies of scale in several sectors, while wages, investment share, openness and specialisation play only a very limited role in explaining (cross-country differences in) energy- and labour-productivity growth.

Energy-intensity developments for 19 OECD countries and 51 sectors

This paper presents stylized facts on energy-intensity developments for 19 OECD countries and 51 sectors over the period 1980âËâ2005. A principal aim of this paper is to introduce and discuss a new database that combines the recently launched ‘EU KLEMS Growth and Productivity Accounts’ with physical-energy data from the International Energy Agency (IEA). We do so by means of an empirical analysis consisting of the following components at various levels of sectoral detail. First, we document per country the growth rates of energy use, value added and energy intensity (i.e. the ratio of energy use to value added). Second, we compare levels of energy intensity across countries and analyze the evolution of the observed cross-country differences over time. Third, by means of a decomposition analysis we calculate for each country to what extent aggregate energy-intensity trends can be explained from, respectively, shifts in the underlying sectoral structure and efficiency improvements within individual sectors. Finally, we identify issues and areas of research within the field of energy economics where these data may be applied fruitfully.

Dutch Sectoral Energy Intensity Developments in International Perspective, 1987–2005

This paper makes use of a new dataset to investigate energy intensity developments in the Netherlands over the period 1987–2005, in comparison with 18 other OECD countries. A key feature of our analysis is that we combine this cross-country perspective with a high level of sector detail, covering 51 sectors. Particularly innovative is our evaluation of energy intensity developments in a wide range of Service sectors. We find that between 1987 and 2005 energy intensity in the Netherlands decreased on average with 0.9% points per year at the aggregate economy level and with 0.2% points at the aggregate manufacturing sector level, whereas it increased with 0.4% points at the aggregate Service sector level. This performance is considerably below the OECD average, and has been especially poor between 1987 and 1995. In terms of energy intensity levels, performance of the Netherlands is close to the OECD average at the aggregate economy level and in Manufacturing. In Services, the energy intensity level in the Netherlands was about 50% lower than the OECD average in 1987, but this lead has almost disappeared by 2005. Finally, we find that in the Manufacturing sector, between 1987 and 2005, about half of the energy efficiency improvements were undone by a shift towards a more energy-intensive industry structure, most notably through growth of the Chemical sector. In the Service sector, on the contrary, shifts in the underlying sector structure helped in slowing down energy intensity increase by about one-third between 1987 and 2005. �

Sectoral Energy- and Labour-Productivity Convergence

This paper provides an empirical analysis of energy- and labour-productivity convergence at a detailed sectoral level for 14 OECD countries, covering the period 1970-1997. A -convergence analysis shows that the development of cross-country variation in productivity performance depends on the level of aggregation. Both patterns of convergence as well as divergence are found. A -convergence analysis provides support for the hypothesis that in most sectors lagging countries tend to catch up with technological leaders, in particular in terms of energy productivity. Moreover, the results show that convergence is conditional rather than unconditional, meaning that productivity levels converge to country-specific steady states, and that cross-country differences of energy-productivity levels are substantially larger than of labour-productivity levels at all levels of sectoral aggregation. Finally, searching for the fundamentals determining cross-country productivity differentials reveals a positive productivity effect of energy prices and economies of scale in several sectors, while wages, investment share, openness and specialization play only a very limited role in explaining (cross-country differences in) energy- and labour-productivity growth. Keywords: energy productivity, labour productivity, convergence, sectoral analysis JEL codes: O13, O47, O5, Q43

International comparison of sectoral energy- and labour-productivity performance; stylised facts and decomposition of trends

This paper simultaneously explores trends in energy- and labour productivity for 14 OECD countries and 13 sectors over the period 1970-1997. A principal aim of this paper is to trace back macroeconomic productivity developments to developments at the level of individual sectors, in order to correct trends in technology-driven productivity improvements for the impact of structural effects. First, we document trends in macroeconomic energy- and labour productivity performance, examining the role of the Manufacturing, Services, Transport and Agricultural sector. Second, we take a closer look at the role of 10 Manufacturing sectors in driving aggregate Manufacturing energy- and labour-productivity performance. A cross-country decomposition analysis reveals that in some countries structural changes contributed considerably to aggregate energy-productivity growth while in other countries they partly offset energy-efficiency improvements. In contrast, structural changes only play a minor role in explaining aggregate labour-productivity developments. We identify for each country the percentage contribution of each sector to aggregate structural and efficiency changes. Furthermore, we find labour productivity growth to be higher on average than energy productivity growth. Over time, this bias towards labour productivity growth is increasing in the Transport, Agriculture and aggregate Manufacturing sectors, while it is decreasing in Services and most Manufacturing sectors.

Comorbidity in childhood asthma

Dit proefschrift heeft als focus comorbiditeit bij kinderen met astma en de impact hiervan op de astma. Comorbiditeiten in kinderen met astma zijn allergische rhinitis(AR), dysfunctioneel ademen(DA) en depressieve aandoeningen. De prevalentie van AR in kinderen met astma is 76.2%. AR was vastgesteld in maar 56.1%. Ongecontroleerd astma komt vaker voor bij kinderen met AR. De invloed op de astma controle verdwijnt wanner er behandeld wordt met intra-nasale steroïden. DA in kinderen met astma werd in 5.3% vastgesteld met de Nijmegen vragenlijst. DA heeft een associatie met minder astma controle. Er werden geen verschillen gevonden in de totale scores voor angst, depressie of in zelfbeeld tussen kinderen met of zonder astma. Het risico op angst of depressie stijgt met slechtere astma controle. Een oorzaak voor ongecontroleerd astma werd gevonden in 97.2%. De oorzaken waren: slechte therapietrouw(37%), persisterende blootstelling aan omgevingsprikkels(28%), comorbiditeiten(20%), (AR en DA zijn de meest voorkomende). Incorrecte inhalatie techniek(8%). Bij zes(4.2%) was er een andere diagnose dan astma. De prevalentie van therapie resistent astma was 2.8%. De conclusies zijn dat therapie resistent astma zeldzaam is. Comorbiditeiten hebben een belangrijke rol als oorzaak. AR is vaak onderkent maar is belangrijk en goed te behandelen. DA komt minder vaak voor, maar heeft invloed op de astma controle. In goed gecontroleerd astma zijn psychologische comorbiditeiten zeldzaam. Bij minder astma controle is er een associatie met een verhoogd risico op psychologische comorbiditeiten

A new approach to (quasi) periodic boundary conditions in micromagnetics: the macrogeometry

We present a new method to simulate repetitive ferromagnetic structures. This macro geometry approach combines treatment of short-range interactions (i.e. the exchange field) as for periodic boundary conditions with a specification of the arrangement of copies of the primary simulation cell in order to correctly include effects of the demagnetizing field. This method (i) solves a consistency problem that prevents the naive application of 3d periodic boundary conditions in micromagnetism and (ii) is well suited for the efficient simulation of repetitive systems of any size

Metal-catalyst-free growth of silica nanowires and carbon nanotubes using Ge nanostructures

The use of Ge nanostructures is investigated for the metal-catalyst-free growth of silica nanowires and carbon nanotubes (CNTs). Silica nanowires with diameters of 10-50 nm and lengths of ? 1 ?m were grown from SiGe islands, Ge dots, and Ge nanoparticles. High-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS) reveal that the nanowires grow from oxide nanoparticles on the sample surface. We propose that the growth mechanism is thermal diffusion of oxide through the GeO2 nanostructures. CNTs with diameters 0.6-2.5 nm and lengths of less than a few ?m were similarly grown by chemical vapor deposition from different types of Ge nanostructures. Raman measurements show the presence of radial breathing mode peaks and the absence of the disorder induced D-band, indicating single walled CNTs with a low defect density. HRTEM images reveal that the CNTs also grow from oxide nanoparticles, comprising a mixture of GeO2 and SiO2