Do Married Women Base Their Labour Supply Decisions on Gross or Marginal Wages?

In the face of complex budget constraints the assumption of rationally acting individuals having complete knowledge of the tax system is a theoretical borderline. The specific issues examined in this study are (i) to what extent do consumers (here married women) perceive their true marginal tax rate when they make their labour supply decisions?, and (ii) how does the perception of the marginal tax rate differ among various socio-economic groups?. Using different approaches and different data sets·we consistently find that (i) against conventional wisdom the assumption of complete knowledge of the tax system does not fit the data well, and that (ii) education appears to be the main determinant of a correct perception of the marginal tax rate. --

On the dynamics of process innovative activity: an empirical investigation using panel data

This paper addresses three major aspects of firms' process innovative activity: forward- looking behaviour, uncertainty w.r.t. returns of R&D investments, and oligopolistic competition on the product market. Assuming that R&D expenditures are cost-reducing investments, we derive an Euler equation for process innovations and discuss alternative panel econometric approaches suitable to the case where only qualitative information is available. Empirical results are based on an unbalanced panel of German manufacturing firms for 1984-1989 and suggest that the Schumpeterian causality from firm size to innovation activity might in fact be attributed, at least partly, to heterogeneity in the perception of process innovative success. --

Schätzung ökonometrischer Modelle auf der Grundlage anonymisierter Daten

Die Anonymisierung von sensiblen Individualdaten führt zu einem Konflikt zwischen dem Ziel der Minimierung des Reidentifikationsrisikos und der Qualität ökonometrischer Schätzungen. Der durch Anonymisierung bedingte Verlust an Effizienz und/oder der Konsistenz eines Schätzers wirft die grundsätzliche Frage auf, inwieweit anonymisierte Individualdaten überhaupt für die wissenschaftliche Nutzung geeignet sind. Deshalb gehen wir in dieser Arbeit der Frage nach, welchen Einfluss Anonymisierungsverfahren auf die Eigenschaften von ökonometrischen Schätzern haben. Zunächst untersuchen wir die Auswirkungen gängiger Anonymisierungsverfahren auf lineare ökonometrische Schätzer in endlichen Stichproben. Im zweiten Schritt untersuchen wir, inwieweit sich die Selektions-effekte durch Anonymisierung aufgrund von Data Blanking mit Hilfe von semiparametrischen Verfahren korrigieren lassen. Die quantitative Evidenz beruht auf Monte-Carlo Simulationen und einer illustrativen Anwendung für einen Querschnitt der Kostenstrukturerhebung.Mikroaggregation, stochastische Überlagerung, Data Blanking, IV-Schätzung, semiparametrisches Selektionsmodell

Superconducting undulator activities at the European X-ray Free-Electron Laser Facility

For more than 5 years, superconducting undulators (SCUs) have been successfully delivering X-rays in storage rings. The European X-Ray Free-Electron Laser Facility (XFEL) plans to demonstrate the operation of SCUs in X-ray free-electron lasers (FELs). For the same geometry, SCUs can reach a higher peak field on the axis with respect to all other available technologies, offering a larger photon energy tunability range. The application of short-period SCUs in a high electron beam energy FEL > 11 GeV will enable lasing at very hard X-rays > 40 keV. The large tunability range of SCUs will allow covering the complete photon energy range of the soft X-ray experiments at the European XFEL without changing electron beam energy, as currently needed with the installed permanent magnet undulators. For a possible continuous-wave (CW) upgrade under discussion at the European XFEL with a lower electron beam energy of approximately 7–8 GeV, SCUs can provide the same photon energy range as available at present with the permanent magnet undulators and electron energies. This paper will describe the potential of SCUs for X-ray FELs. In particular, it will focus on the different activities ongoing at the European XFEL and in collaboration with DESY to allow the implementation of SCUs in the European XFEL in the upcoming years

Tracking Virus-Specific CD4+ T Cells during and after Acute Hepatitis C Virus Infection

CD4+ T cell help is critical in maintaining antiviral immune responses and such help has been shown to be sustained in acute resolving hepatitis C. In contrast, in evolving chronic hepatitis C CD4+ T cell helper responses appear to be absent or short-lived, using functional assays. Here we used a novel HLA-DR1 tetramer containing a highly targeted CD4+ T cell epitope from the hepatitis C virus non-structural protein 4 to track number and phenotype of hepatitis C virus specific CD4+ T cells in a cohort of seven HLA-DR1 positive patients with acute hepatitis C in comparison to patients with chronic or resolved hepatitis C. We observed peptide-specific T cells in all seven patients with acute hepatitis C regardless of outcome at frequencies up to 0.65% of CD4+ T cells. Among patients who transiently controlled virus replication we observed loss of function, and/or physical deletion of tetramer+ CD4+ T cells before viral recrudescence. In some patients with chronic hepatitis C very low numbers of tetramer+ cells were detectable in peripheral blood, compared to robust responses detected in spontaneous resolvers. Importantly we did not observe escape mutations in this key CD4+ T cell epitope in patients with evolving chronic hepatitis C. During acute hepatitis C a CD4+ T cell response against this epitope is readily induced in most, if not all, HLA-DR1+ patients. This antiviral T cell population becomes functionally impaired or is deleted early in the course of disease in those where viremia persists

Dysfunctional CD8(+) T cells in hepatitis B and C are characterized by a lack of antigen-specific T-bet induction

The transcription factor T-bet regulates the production of interferon-γ and cytotoxic molecules in effector CD8 T cells, and its expression correlates with improved control of chronic viral infections. However, the role of T-bet in infections with differential outcome remains poorly defined. Here, we report that high expression of T-bet in virus-specific CD8 T cells during acute hepatitis B virus (HBV) and hepatitis C virus (HCV) infection was associated with spontaneous resolution, whereas T-bet deficiency was more characteristic of chronic evolving infection. T-bet strongly correlated with interferon-γ production and proliferation of virus-specific CD8 T cells, and its induction by antigen and IL-2 stimulation partially restored functionality in previously dysfunctional T-bet–deficient CD8 T cells. However, restoration of a strong interferon-γ response required additional stimulation with IL-12, which selectively induced the phosphorylation of STAT4 in T-bet(+) CD8 T cells. The observation that T-bet expression rendered CD8 T cells responsive to IL-12 suggests a stepwise mechanism of T cell activation in which T-bet facilitates the recruitment of additional transcription factors in the presence of key cytokines. These findings support a critical role of T-bet for viral clearance and suggest T-bet deficiency as an important mechanism behind chronic infection