430 research outputs found

    The euro – more than just a currency. Bertelsmann Impulse #2015/01

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    Working together is worthwhile; growing together even more so. After more than 20 years of the single market and 15 years of monetary union, the members of the European Union – once referred to as the European Community – are interwoven. Indeed, they are very closely interconnected. Despite this, in the face of heated debates arising once again over a looming sovereign default by Greece, there is once again an uneasy feeling about having to pay up for the debts of other member states. In Germany, the largest contributor country, the willingness to act in solidarity is steadily decreasing. And this is despite the fact that Germany profits from the euro in many ways. Even in the country with the strongest economy, many are asking themselves whether this is the beginning of the end for the euro zone

    Evaluation of hydropower upgrade projects - a real options approach

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    When evaluating whether to refurbish existing hydropower plants or invest in a new power plant, there are two important aspects to take into consideration. These are the capacity chosen for the production facilities and the timing of the investment. This paper presents an investment decision support framework for hydropower producers with production facilities due for restoration. The producer can choose between refurbishing existing power plants and investing in a new production facility. A real options framework is proposed to support the investment decision. Using a case from Norsk Hydro ASA, a Norwegian hydropower producer, we employ the framework to evaluate the investment opportunities. Our main contribution is an approach that combines hydropower scheduling and real options valuation, and the results from our analysis suggest feasible investment strategies for Norsk Hydro ASA.Electricity price uncertainty; reservoir management; hydroelectric scheduling; investment under uncertainty; electricity markets

    Source regions of some persistent organic pollutants measured in the atmosphere at Birkenes, Norway

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    A key feature of POPs (Persistent Organic Pollutants) is their potential for long-range atmospheric transport. In order to better understand and predict atmospheric source-receptor relationships of POPs, we have modified an existing Lagrangian transport model (FLEXPART) to include some of the key processes that control the atmospheric fate of POPs. We also present four years (2004–2007) of new atmospheric measurement data for polychlorinated biphenyls (PCBs) and hexachlorocyclohexanes (HCHs) obtained at Birkenes, an EMEP (European Monitoring and Evaluation Programme) site in southern Norway. The model overestimates measured PCB-28 and g-HCH concentrations by factors of 2 and 8, respectively, which is most likely because the emissions used as input to the model are overestimated. FLEXPART captures the temporal variability in the measurements very well and, depending on season, explains 31–67% (14–62%) of the variance of measured PCB-28 (g-HCH) concentrations. FLEXPART, run in a time-reversed (adjoint) mode, was used to identify the source regions responsible for the POP loading at the Birkenes station. Emissions in Central Europe and Eastern Europe contributed 32% and 24%, respectively, to PCB-28 at Birkenes, while Western Europe was found to be the dominant source (50%) for g-HCH. Intercontinental transport from North America contributed 13% for g-HCH. While FLEXPART has no treatment of the partitioning of POPs between different surface media, it was found a very useful tool for studying atmospheric source-receptor relationships for POPs and POP-like chemicals that do not sorb strongly to atmospheric particles and whose atmospheric levels are believed to be mainly controlled by primary sources

    Anisotropic Superexchange for nearest and next nearest coppers in chain, ladder and lamellar cuprates

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    We present a detailed calculation of the magnetic couplings between nearest-neighbor and next-nearest-neighbor coppers in the edge-sharing geometry, ubiquitous in many cuprates. In this geometry, the interaction between nearest neighbor coppers is mediated via two oxygens, and the Cu-O-Cu angle is close to 90 degrees. The derivation is based on a perturbation expansion of a general Hubbard Hamiltonian, and produces numerical estimates for the various magnetic energies. In particular we find the dependence of the anisotropy energies on the angular deviation away from the 90 degrees geometry of the Cu-O-Cu bonds. Our results are required for the correct analysis of the magnetic structure of various chain, ladder and lamellar cuprates.Comment: 13 pages, Latex, 7 figure

    Nährstoffbilanzen ökologischer Gemüsebaubetriebe in Süd-West-Deutschland

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    Der Öko-Gemüsebau zeichnet sich durch ein anspruchsvolles Nährstoffmanagement aus mit hohem Nährstoffbedarf des Gemüses und vergleichsweise kurzen Wachstumsperioden. Der Ansatz der Hoftorbilanzierung zielt darauf ab, den Status quo des Düngemanagements für N, P und K auf Gemüsebetrieben aufzuzeigen
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