Tax Incentives and Household Portfolios: A Panel Data Analysis

This paper investigates the responsiveness of household portfolios to tax incentives by exploiting a substantial tax reform that altered after-tax returns and cost of debt for a large number of households. An extraordinary panel data set that covers two years before and after the reform is used for the analysis. Our empirical findings suggest that households reshuffle their balance sheets in the case of a partial deductibility phase-out. In particular, heavily taxed, interest-bearing assets are used to pay off mortgage debt. Furthermore, we find that taxes have a significant impact on the structure of household portfolios even after controlling for unobserved heterogeneity.Household portfolios, taxation, panel data, natural experiment

Strong-field approximation for Coulomb explosion of H_2^+ by short intense laser pulses

We present a simple quantum mechanical model to describe Coulomb explosion of H$_2^+$ by short, intense, infrared laser pulses. The model is based on the length gauge version of the molecular strong-field approximation and is valid for pulses shorter than 50 fs where the process of dissociation prior to ionization is negligible. The results are compared with recent experimental results for the proton energy spectrum [I. Ben-Itzhak et al., Phys. Rev. Lett. 95, 073002 (2005), B. D. Esry et al., Phys. Rev. Lett. 97, 013003 (2006)]. The predictions of the model reproduce the profile of the spectrum although the peak energy is slightly lower than the observations. For comparison, we also present results obtained by two different tunneling models for this process.Comment: 8 pages, 4 figure

Approximate polynomial structure in additively large sets

We show that any subset of the natural numbers with positive logarithmic Banach density contains a set that is within a factor of two of a geometric progression, improving the bound on a previous result of the authors. Density conditions on subsets of the natural numbers that imply the existence of approximate powers of arithmetic progressions are developed and explore

Grammatikkens rolle i fremmedsprogsundervisning på gymnasiet og universitetet

Denne artikel har til formål at diskutere tilrettelæggelsen af grammatikundervisningen i fremmedsprogene på gymnasie- og universitetsniveau. På baggrund af resultater fra to empiriskeundersøgelser, som fokuserer på elevers/studerendes og underviseres antagelser om grammatik, påpeger vi nødvendigheden af et forstærket fokus på fagdidaktik og en gentænkning afgrammatikkens rolle i sprogundervisningen