Increasing the credibility of the twin birth instrument

Twin births are an important instrument for the endogenous fertility decision. However, twin births are not exogenous either as dizygotic twinning is correlated with maternal characteristics. Following the medical literature, we assume that monozygotic twins are exogenous, and construct a new instrument, which corrects for the selection although monozygotic twinning is usually unobserved in survey and administrative datasets. Using administrative data from Sweden, we show that the usual twin instrument is related to observed and unobserved determinants of economic outcomes, while our new instrument is not. In our applications we find that the classical twin instrument underestimates the negative effect of fertility on labor income. This finding is in line with the observation that high earners are more likely to delay childbearing and hence have a higher risk to get dizygotic twins.     

Longitudinal Plankton Dynamics in the Rivers Rhine and Elbe

We compared the longitudinal plankton development in the two large rivers Rhine and Elbe by means of four Lagrangian sampling campaigns performed within the time span 2009–2011. The campaigns revealed low chlorophyll concentrations in the Rhine along a long river stretch (Rhine‐km 170 to 854) with maximum values below 5 µg L^?1 in 2010. In contrast, the Elbe (Elbe‐km 4 to 582) showed high and longitudinally increasing chlorophyll concentrations with maximal values of 174 µg L^?1 in 2009 and 123 µg L^?1 in 2011. Additional samples of the benthic bivalves along the river stretches revealed high densities of the filter feeders in the Rhine that could potentially explain losses of plankton production. Their densities in the Elbe were significantly lower, making important losses to benthic filter feeders unlikely. However, strong phytoplankton growth was observed during the sampling campaign in 2011 in the Rhine coinciding with a low discharge event. This resulted in an exceptionally high chlorophyll value of up to 244 µg L^?1 in the lower river sections, a value that was not reached in the last two decades of continuous water quality monitoring in the Rhine. Even though we cannot fully explain this phenomenon, it shows that phytoplankton has a high growth potential in the Rhine but is usually controlled by other mechanisms. Tributaries represented an additional and important source of plankton biomass and suspended substances in the Rhine, whereas they primarily diluted the plankton concentrations in the Elbe. Copyright © 2015 John Wiley & Sons, Ltd.     

Gemeinsame österreichisch-ungarische Sedimentforschung im Rahmen des EFRE-Projektes SEDDON

The multiple uses of the Danube River for navigation, hydropower production and as a drinking water supply influence its ecological quality. Flow restrictions due to regulation as well as impacts on the sediment regime such as retention in the catchment area and interruption of the sediment continuum result in changes of the hydromorphological structures and can produce major problems in the context of sediment management. In light of these facts, cross-border investigations of sediment transport at the Danube River are called for. As there are no uniform research approaches shared by Austria and Hungary, the EU-funded project SEDDON (Sediment Research and Management at the Danube River) aims to compare different monitoring and modeling techniques used to determine sediment transport, and to develop mutual solutions. Further, the laboratory equipment currently used for hydraulic model experiments is evaluated and a research channel with a free flowing discharge of up to 10 m³/s without pumping will be constructed, allowing large-scale joint laboratory tests concerning sediment to be performed.     

Erstens: ignorieren, zweitens: diffamieren, drittens: umarmen?

Mass media are an essential factor for the success of small parties, for the media can act in a supporting or an inhibiting way towards these parties. This could be observed for the example of the German Green Party: As the Greens were becoming more and more important in the parliaments, the media changed their formerly very critical view of the party to a more factual and positive reporting. Is the party “Die Linke” now experiencing a similar process? The present study analyses the comments of three national German newspapers from 2005 to 2009, using a quantitative content analysis with the aim of bringing to light how the media acted towards “Die Linke”. The results show that commenting has hardly changed since earlier studies were published. Factual issues only play a marginal role, and the party is judged negatively in all newspapers, with the tageszeitung slightly distinct from the other two papers, though.     

Invasive species management in a spatially heterogeneous world: Effects of uniform policies

The spread of invasive species (IS) is an inherently spatial process, and management of invasive species occurs over spatially heterogeneous regions, but policy constraints can restrict management responses to be homogeneous across regions. Using a spatial bioeconomic model that includes a representation of invasive species ecology based on heterogeneous environments that are linked across space and time by human and ecological pathways, we compare optimal spatially heterogeneous policy to spatially uniform policy. We explore the magnitude and pattern of the policy differences with emphasis on the influence of different types of underlying heterogeneity across locations.     

Schmerzen erkennen

Schmerzeinsch?tzung im Alter und bei Demenz - Menschen mit Demenz k?nnen h?ufig keine Selbstauskunft über ihr Schmerzerleben geben. Sie sind darauf angewiesen, dass die Schmerzen von anderen erkannt werden. Welche pflegerischen Instrumente erleichtern die Fremdeinsch?tzung von Schmerzen?