Working Paper 02-02 - The impacts of energy and carbon taxation in Belgium - Analysis of the impacts on the economy and on CO2 emissions

This working paper brings together three analyses that were carried out by the Federal Planning Bureau at the request of the Secretary of State for Energy and Sustainable Development and the Minister for Consumer Affairs, Public Health and the Environment. It looks at the harmonisation (increase) in energy levies up to the average level in our neighbouring countries and the introduction of a co2 levy. In the case of the co2 levy we analyse both the situation whereby all energy products are taxed and the case where the levy is only applicable to road transport. All policy variants are intended to reduce co2 emissions in Belgium within the context of the Kyoto Protocol. The analyses presented in this working paper were finalized in September 2001.

The influence of study characteristics on coordinate-based fMRI meta-analyses

1 Introduction The reproducibility of fMRI studies suffers from small sample sizes, an overly stringent focus on minimizing type I errors (at the cost of power) and topological instability (Durnez et al., 2014; Roels et al., 2015). It is therefore increasingly recognized that further progress in understanding brain function will require integration of data across studies using meta-analyses (Wager et al., 2007). Methods for coordinate-based meta-analyses are designed to determine locations of activity based on studies that only report peak voxels whose evidence survive a selected threshold. In this contribution, we study the impact of analysis choices made at the individual study level on the coordinate-based meta-analysis methods. More specifically, we focus on pooling of subjects in which we consider (1) fixed effects pooling (no between-subjects variability), (2) ordinary least squares or OLS (homogeneous within-subjects variances) and (3) mixed effects pooling (estimating both). We use a large database to set up a simulation study and implement 3 coordinate- based meta-analysis techniques: activation likelihood estimation (ALE, Turkeltaub et al., 2002) and two weighted average meta-analyses. ALE calculates the convergence of activation at a specific voxel. The weighted average meta-analysis is either implemented as a fixed effects meta-analysis (assumes no between study variability) or a random effects meta-analysis (seed based d-mapping, SBdM, Radua et al. (2012)). 2 Method The design of the study is depicted in figure 1. We use data of 1400 subjects from the processed math > language contrast of the IMAGEN project (Schumann et al., 2010). In one iteration, 200 subjects are sampled that go into a ‘ground truth’ for which activation is assessed through mixed effects pooling with the False Discovery Rate (FDR) controlled at level 0.001. The other 200 subjects go into a test condition and are then sampled as 10 separate studies. Within each study, we apply the three different pooling methods and we obtain peak locations (FDR control at level 0.05). These study results are then combined in meta-analyses. For ALE, images are either uncorrected for multiple testing or corrected through FDR control (‘pID’ assumes independent or positive de- pendent test statistics among voxels, ‘pID’ makes no assumption on the joint distribution of test statistics). All meta-analyses are thresholded to control the type I error rate or FDR at level 0.05. The meta-analytic results are compared with the ground truth (200 different subjects) and a benchmark (group analysis as in ground truth but using the same 200 subjects as in the meta-analyses). We calculate the overlap-of-activation, power and false positive rate, FPR (Maitra, 2010). In total, 30 iterations are performed. 3 Results Results are given in figure 2. At study level, the OLS pooling method shows consistently lower levels of overlap, power and FPR while the mixed effects pooling method has the highest levels of overlap, power and FPR. For the meta-analysis methods, the fixed and random effects analyses show higher levels of overlap and power compared to ALE though with a slight increase in FPR. 4 Conclusions With this study, we show how analytical choices at the individual study level impact results on the meta-analytical level. More specifically, OLS leads to more conservative results while fixed/mixed effects pooling is more liberal. The different performance of the meta-analysis methods requires further research. One possible explanation is the implemented kernel sizes to model local maxima that differ between the methods

Non-mammalian model organisms in epigenetic research : an overview

Recent advances in sequencing technology and genome editing tools had an indisputably enormous impact on our understanding of complex biological pathways and their genetic and epigenetic regulation. Unlike genetics, a study of phenotype development as a result of genotypic diversity, epigenetics studies the emergence of (possibly heritable) phenotypic assortment from one DNA sequence. Epigenetic modifications (i.e., DNA methylation, histone tail modifications, noncoding RNA interference, and many others) are diverse and can bring an additional layer of complexity to phenotype development and it's inheritance. Still, today, detailed mechanisms behind the development of epigenetic marks, their interaction, and their role in transgenerational inheritance of phenotypes are not fully understood. Therefore, chromatin biology and epigenetic research have a rich history of chasing discoveries in a variety of model organisms, including yeast, worms, flies, fish, and plants. Use of these models has opened numerous new avenues for investigation in the field. In the coming future, model organisms will continue to serve as an inseparable part of studies related to interpreting complex genomic and epigenomic data, gene–protein functional relationship, various diseases pathways, aging, and many others. Use of the model organism will provide insights not only into novel genetic players but also the profound impact of epigenetics on phenotype development. Here, we present a brief overview of the most commonly used nonmammalian model organism (i.e., fruit fly, nematode worm, zebrafish, and yeast) as potential experimental systems for epigenetic studies

Analytic properties of two-carousel systems

We present analytic results for warehouse systems involving pairs of carousels. Specifically, for various picking strategies, we show that the sojourn time of the picker satisfies an integral equation that is a contraction mapping. As a result, numerical approximations for performance measures such as the throughput of the system are extremely accurate and converge fast (e.g.\ within 5 iterations) to their real values. We present simulation results validating our results and examining more complicated strategies for pairs of carousels.Comment: 28 pages, 17 figure

Working Paper 09-11 - Impact of the EU Climate-Energy Package on the Belgian energy system and economy - Update 2010 Study commissioned by the Belgian federal authority

By the end of 2008, the Federal Planning Bureau published the Working Paper 21-08. This Working Paper described and analysed the impact of the EU Climate-Energy Package on the Belgian energy system and economy. Since then, however, a lot has changed: the macroeconomic projections altered radically further to the financial and economic crisis, recent developments in the field of oil and gas supply and demand made fossil fuel price projections to be revised upwards and a number of energy efficiency measures were agreed upon and put into law in the course of 2008 and 2009. All this made the 2008 study less relevant whilst only 2 years old. This study report then updates the analysis reported in the Working Paper 21-08 and dedicates special attention to the stepping up to -30% for the EU greenhouse gas reduction target. It is based on the new economic and policy context and benefits from recent analyses of the European Commission conducted at EU level.Climate policy, Economic efficiency, Energy policy, Greenhouse gas emissions, Long-term energy projections, Macroeconomic impact