Suchergebnisse

"In this paper we seek to produce forecasts of commodity price movements that can systematically improve on naive statistical benchmarks, and revisit the forecasting performance of changes in commodity currencies as efficient predictors of commodity prices, a view emphasized in the recent literature. In addition, we consider different types of factor-augmented models that use information from a large data set containing a variety of indicators of supply and demand conditions across major developed and developing countries. These factor-augmented models use either standard principal components or partial least squares (PLS) regression to extract dynamic factors from the data set. Our forecasting analysis considers ten alternative indices and sub-indices of spot prices for three different commodity classes across different periods. We find that the exchange rate-based model and especially the PLS factor-augmented model are more prone to outperform the naive statistical benchmarks. However, across our range of commodity price indices we are not able to generate out-of-sample forecasts that, on average, are systematically more accurate than predictions based on a random walk or autoregressive specifications"--National Bureau of Economic Research web site

Although the Netherlands is one of the most densely populated countries, two thirds of the land area are still under agricultural use. Major socio-economic changes are however expected for the agricultural sector. The increasing globalisation of economic relations in agriculture and the possible reduction of European price support to farmers are examples of such developments that may affect agricultural land use. At the same time other land use functions put increasing pressure on rural land in order to accommodate housing, employment, recreation and water storage. The present study takes a closer look at the expected spatial developments and simulates possible future land use patterns by using an economics based land use model. Two opposing scenarios of anticipated land use change are used to illustrate the possible extremes of future land use configurations. These scenarios vary both in their quantitative and qualitative description of the projected changes. The simulation of low-density residential areas in green areas will illustrate this approach. The development of these new rural living areas is currently a sensitive topic in the public debate on urbanisation. The simulated urbanisation patterns are evaluated in terms of their impact on spatial policy related issues through the application of newly developed indicators. For decades the Dutch government has strived for compact forms of urbanisation in order to preserve the remaining stretches of open space. The applied metrics of land use change will therefor focus on the concentration of urbanisation and the fragmentation of open space. The findings of this study may be especially interesting now Dutch spatial policy seems to be on the brink of loosening its traditional grip on spatial planning.

The Netherlands is one of the most densely populated countries in the world and urban functions are constantly claiming more space. This continuing urbanisation has lead to a growing concern for the preservation of open space. A loss of open space does not only mean a fragmentation of ecosystems or (potential) animal habitat but also affects the geographical, historical and cultural qualities of the landscape. The preservation of open space is an important theme in the spatial planning of the Netherlands. The Dutch government strives to keep the total volume of open space at a reasonable high level and tries to avoid the fragmentation of open space. The present research deals with the modelling of future land use and will focus more specifically on the fragmentation of open space. A GIS-oriented land use model will be used to study this subject. Assessing the impact of land use change on open space calls for a thorough definition of open space that takes into account the shape and size characteristics of various land use functions. This definition is strongly related to the policy context that introduces the concept of open space. In the Dutch, anthropocentric practice open space does not necessarily refer to large natural areas with high ecological values, but it rather relates to large areas with relatively few buildings. This might for example exclude wooded areas that do not offer panoramic views. Single objects (high voltage or television masts) can also severely affect the individual experience of open space. GIS-technology allows for a quantitative implementation of the concept of open space. It furthermore facilitates the spatial analysis of the impact of land use changes. Different simulations from land use models will be assessed both in terms of a total loss in the volume of open space and the localised impact in terms of fragmentation. To study the latter impact a methodology will be developed that will adopt experiences from spatial ecological research on habitat fragmentation.

OBJECTIVE: The aim of this study is to examine the experience of European surgeons on autologous fat transfer (AFT) and highlight differences between countries and levels of experience. BACKGROUND DATA: The popularity of AFT causes an increase in sophisticated scientific research and clinical implementation. While results from the former are well-documented, important aspects of the latter are far less recognized. METHODS: An international survey study about surgeon background, besides AFT familiarity, technique, and opinion, was distributed among surgeons from 10 European countries. The differences between countries and levels of experience were analyzed using a logistic regression model. RESULTS: The mean respondent age, out of the 358 completed questionnaires, was 46 years. Ninety-seven percent of the respondents were plastic surgeons, who practiced AFT mostly in breast surgery and considered themselves experienced with the technique. The thigh and abdomen were less favored harvest locations by the Belgium and French respondents, respectively, and both the French and Austrian respondents preferred manual aspiration over liposuction in harvesting the fat. Despite minor differences between countries and experience, the intraglandular space was injected in all subgroups. CONCLUSIONS: The expanding use of AFT in Europe will lead to more experience and heterogeneity regarding the technique. However, despite an obvious adherence to Coleman's method, deviations thereof become more apparent. An important example of such a deviation is the ongoing practice of intraglandular AFT despite being a contraindication in various European guidelines. These unsafe practices should be avoided until scientific clarification regarding oncological safety is obtained and should therefore be the focus of surgeon education in Europe.

Objective. The aim of this study is to examine the experience of European surgeons on autologous fat transfer (AFT) and highlight differences between countries and levels of experience. Background Data. The popularity of AFT causes an increase in sophisticated scientific research and clinical implementation. While results from the former are well-documented, important aspects of the latter are far less recognized. Methods. An international survey study about surgeon background, besides AFT familiarity, technique, and opinion, was distributed among surgeons from 10 European countries. The differences between countries and levels of experience were analyzed using a logistic regression model. Results. The mean respondent age, out of the 358 completed questionnaires, was 46 years. Ninety-seven percent of the respondents were plastic surgeons, who practiced AFT mostly in breast surgery and considered themselves experienced with the technique. The thigh and abdomen were less favored harvest locations by the Belgium and French respondents, respectively, and both the French and Austrian respondents preferred manual aspiration over liposuction in harvesting the fat. Despite minor differences between countries and experience, the intraglandular space was injected in all subgroups. Conclusions. The expanding use of AFT in Europe will lead to more experience and heterogeneity regarding the technique. However, despite an obvious adherence to Coleman's method, deviations thereof become more apparent. An important example of such a deviation is the ongoing practice of intraglandular AFT despite being a contraindication in various European guidelines. These unsafe practices should be avoided until scientific clarification regarding oncological safety is obtained and should therefore be the focus of surgeon education in Europe.