National Fund for Scientific Research

About: National Fund for Scientific Research is a nonprofit organization based out in Brussels, Belgium. It is known for research contribution in the topics: Population & Alexithymia. The organization has 578 authors who have published 958 publications receiving 43376 citations.

The European Soil Erosion Model (EUROSEM): A dynamic approach for predicting sediment transport from fields and small catchments.

Abstract: The European Soil Erosion Model (EUROSEM) is a dynamic distributed model, able to simulate sediment transport, erosion and deposition over the land surface by rill and interill processes in single storms for both individual fields and small catchments. Model output includes total runoff, total soil loss, the storm hydrograph and storm sediment graph. Compared with other erosion models, EUROSEM has explicit simulation of interill and rill flow; plant cover effects on interception and rainfall energy; rock fragment (stoniness) effects on infiltration, flow velocity and splash erosion; and changes in the shape and size of rill channels as a result of erosion and deposition. The transport capacity of runoff is modelled using relationships based on over 500 experimental observations of shallow surface flows. EUROSEM can be applied to smooth slope planes without rills, rilled surfaces and surfaces with furrows. Examples are given of model output and of the unique capabilities of dynamic erosion modelling in general. © 1998 John Wiley & Sons, Ltd.

The Economics of Migrants' Remittances

Abstract: This chapter reviews the recent theoretical and empirical economic literature on migrants' remittances. It is divided between a microeconomic section on the determinants of remittances and a macroeconomic section on their growth effects. At the micro level we first present in a fully harmonized framework the various motivations to remit described so far in the literature. We show that models based on different motives share many common predictions, making it difficult to implement truly discriminative tests in the absence of sufficiently detailed data on migrants and receiving households' characteristics and on the timing of remittances. The results from selected empirical studies show that a mixture of individualistic (e.g., altruism, exchange) and familial (e.g., investment, insurance) motives explain the likelihood and size of remittances; some studies also find evidence of moral hazard on the recipients' side and of the use of inheritance prospects to monitor the migrants' behavior. At the macro level we first briefly review the standard (Keynesian) and the trade-theoretic literature on the short-run impact of remittances. We then use an endogenous growth framework to describe the growth potential of remittances and present the evidence for different growth channels. There is considerable evidence that remittances (in the form of savings repatriated by return migrants) promote access to self-employment and raise investment in small businesses, and there is also evidence that remittances contribute to raise educational attainments of children in households with migrant members. Investigation of the effects of remittances on outcomes such as children's education and health raise identification issues, however, as we explain below. Finally, the relationship between remittances and inequality appears to be non-monotonic: remittances seem to decrease economic inequality in communities with a long migration tradition but to increase inequality within communities at the beginning of the migration process. This is consistent with different theoretical arguments regarding the role of migration networks and/or the dynamics of wealth transmission between successive generations.

Exact and approximate rebinning algorithms for 3-D PET data

Abstract: This paper presents two new rebinning algorithms for the reconstruction of three-dimensional (3-D) positron emission tomography (PET) data. A rebinning algorithm is one that first sorts the 3-D data into an ordinary two-dimensional (2-D) data set containing one sinogram for each transaxial slice to be reconstructed; the 3-D image is then recovered by applying to each slice a 2-D reconstruction method such as filtered-backprojection. This approach allows a significant speedup of 3-D reconstruction, which is particularly useful for applications involving dynamic acquisitions or whole-body imaging. The first new algorithm is obtained by discretizing an exact analytical inversion formula. The second algorithm, called the Fourier rebinning algorithm (FORE), is approximate but allows an efficient implementation based on taking 2-D Fourier transforms of the data. This second algorithm was implemented and applied to data acquired with the new generation of PET systems and also to simulated data for a scanner with an 18/spl deg/ axial aperture. The reconstructed images were compared to those obtained with the 3-D reprojection algorithm (3DRP) which is the standard "exact" 3-D filtered-backprojection method. Results demonstrate that FORE provides a reliable alternative to 3DRP, while at the same time achieving an order of magnitude reduction in processing time.

Precarious Employment: Understanding an Emerging Social Determinant of Health

Abstract: Employment precariousness is a social determinant that affects the health of workers, families, and communities. Its recent popularity has been spearheaded by three main developments: the surge in “flexible employment” and its associated erosion of workers' employment and working conditions since the mid-1970s; the growing interest in social determinants of health, including employment conditions; and the availability of new data and information systems. This article identifies the historical, economic, and political factors that link precarious employment to health and health equity; reviews concepts, models, instruments, and findings on precarious employment and health inequalities; summarizes the strengths and weaknesses of this literature; and highlights substantive and methodological challenges that need to be addressed. We identify two crucial future aims: to provide a compelling research program that expands our understanding of employment precariousness and to develop and evaluate policy programs ...