Probleme bei sozialen Experimenten: Lehren aus US-amerikanischen Arbeitsmarktprogrammen

When evaluating a pilot or demonstration program, there are risks from drawing inferences from a single test. This paper reviews the experiences of replication efforts from demonstrations using randomized controlled trials in the initial evaluation and the replications. Although replications of promising programs are primarily gathered to increase sample size, replications are also used to learn if the intervention is successful for other target groups and geographic locations, and to vary some of the intervention's features. In many cases, replications fail to achieve the same success as the original evaluation, and the paper reviews reasons that have been suggested for such failures. The paper reviews what has been learned from replications where random assignment was used in six instances: income maintenance experiments, unemployment insurance bonus experiments, the Center for Employment Training program, job clubs, job search experiments, and the Quantum Opportunity Program. The paper concludes by summarizing lessons learned from the review and areas where more research is needed

A note on separability and intra-household resource allocation in a collective household model

Published in Review of Economics of the Household https://doi.org/10.1007/s11150-012-9155-8</p

Natural-Resource or Market-Seeking FDI in Russia? An Empirical Study of Locational Factors Affecting the Regional Distribution of FDI Entries

This paper conducts an empirical study of the factors that affect the spatial distribution of foreign direct investment (FDI) across regions in Russia; in particular, this paper is concerned with those regions that are endowed with natural resources and marketrelated benefits. Our analysis employs data on Russian firms with a foreign investor during the 2000-2009 period and linked regional statistics in the conditional logit model. The main findings are threefold. First, we conclude that one theory alone is not able to explain the geographical pattern of foreign investments in Russia. A combination of determinants is at work; market-related factors and the availability of natural resources are important factors in attracting FDI. The relative importance of natural resources seems to grow over time, despite shocks associated with events such as the Yukos trial. Second, existing agglomeration economies encourage foreign investors by means of forces generated simultaneously by sector-specific and inter-sectoral externalities. Third, the findings imply that service-oriented FDI co-locates with extraction industries in resource-endowed regions. The results are robust when Moscow is excluded and for subsamples including only Greenfield investments or both Greenfield investments and mergers and acquisitions (M&A).Dieses Arbeitspapier ist eine empirische Studie der Faktoren, die auf den räumlichen Verteilungsprozess von Auslandsdirektinvestitionen (FDI) in den russischen Regionen wirken. Insbesondere befasst sich die Studie dabei mit den Regionen, die mit natürlichen Ressourcen und umfassenden Märkten ausgestattet sind. In unserer Analyse kombinieren wir umfangreiche Regionaldaten mit Firmendaten russischer Unternehmen, in die mindestens ein ausländischer Investor im Zeitraum zwischen 2000 und 2009 investiert hat. Die Analyse nach den Standortfaktoren wird in einem Conditional Logit Modell untersucht. Die grundlegenden Ergebnisse der Studie sind dreifach zu differenzieren. Erstens kann festgestellt werden, dass eine Theorie alleine nicht ausreicht, um das geographische Muster von FDI in Russland zu erklären. Vielmehr kann eine Kombination der Determinanten festgestellt werden; marktbedingte Faktoren und die Zugänglichkeit von natürlichen Ressourcen stellen sich als wichtige Komponenten für die Ansiedlung ausländischer Investoren dar. Der Einfluss natürlicher Ressourcen ist dabei stetig über die Zeit gewachsen, ungeachtet von exogenen Schocks wie beispielsweise dem Yukos-Prozess. Zweitens wirken Agglomerationseffekte auf die Standwortwahl ausländischer Investoren sowohl durch sektorspezifische als auch durch intersektorale Externalitäten. Drittens zeigen die Ergebnisse, dass der Zugang zu natürlichen Ressourcen FDI in Dienstleistungssektoren nach sich zieht. Auch wenn Investitionen in Moskau ausgegrenzt bzw. M&A (Mergers & Acquistions) Investitionen hinzugenommen werden, bleiben die Regressionsergebnisse stabil

Origin, diversification and substrate specificity in the family of NCS1/FUR transporters

NCS1 proteins are H+/Na+ symporters specific for the uptake of purines, pyrimidines and related metabolites. In this article, we study the origin, diversification and substrate specificity of fungal NCS1 transporters. We show that the two fungal NCS1 sub-families, Fur and Fcy, and plant homologues originate through independent horizontal transfers from prokaryotes and that expansion by gene duplication led to the functional diversification of fungal NCS1. We characterised all Fur proteins of the model fungus Aspergillus nidulans and discovered novel functions and specificities. Homology modelling, substrate docking, molecular dynamics and systematic mutational analysis in three Fur transporters with distinct specificities identified residues critical for function and specificity, located within a major substrate binding site, in transmembrane segments TMS1, TMS3, TMS6 and TMS8. Most importantly, we predict and confirm that residues determining substrate specificity are located not only in the major substrate binding site, but also in a putative outward-facing selective gate. Our evolutionary and structure-function analysis contributes in the understanding of the molecular mechanisms underlying the functional diversification of eukaryotic NCS1 transporters, and in particular, forward the concept that selective channel-like gates might contribute to substrate specificity. •NCS1 proteins are H+/Na+ symporters specific for the uptake of purines, pyrimidines and related metabolites. •NCS1 subfamilies, Fur and Fcy, originate through independent horizontal transfers from prokaryotes and expand in Fungi (A). •Modelling, substrate docking, molecular dynamics define the substrate binding site of Fur transporters (B) •Mutational analysis confirms the identity of the substrate binding (C) •An outward-facing selective gate contributes to substrate specificity in FurD (D). © 2015 John Wiley &amp; Sons Ltd