Greenhouse gas exchange of organic soils in Northwest Germany : effects of organic soil cultivation, agricultural land use and restoration

To date, there is still a lack of reliable data about fluxes of greenhouse gases and global warming potentials for organic soils to determine the climatic relevance and supply the National Inventory Report for the German Greenhouse Gas Inventory. In this study, flux rates of carbon dioxide, nitrous oxide and methane and global warming potentials for different organic soils in Northern Germany were achieved. The gas exchange was measured roughly monthly year-round with a closed chamber technique. Transparent and opaque closed chambers were used, to separate ecosystem respiration and gross primary production, and to include the vegetation in the measurements, to factor the influence of the plants into the gas exchange. The CO2 exchange was modelled at high resolution with site parameters with the measured and modelled values fitting very well together. A recommended measure is to achieve a water level of a few centimetres below ground surface. A high intensity land use should be avoided. Because of inter-annual variation, measurements over several years are necessary

Towards a new ITU-T recommendation for subjective methods evaluating gaming QoE

This paper reports on activities in Study Group 12 of the International Telecommunication Union (ITU-T SG12) to define a new Recommendation on subjective evaluation methods for gaming Quality of Experience (QoE). It first resumes the structure and content of the current draft which has been proposed to ITU-T SG12 in September 2014 and then critically discusses potential gaming content and evaluation methods for inclusion into the upcoming Recommendation. The aim is to start a discussion amongst experts on potential evaluation methods and their limitations, before finalizing a Recommendation. Such a recommendation might in the end be applied by non -expert users, hence wrong decisions in the evaluation design could negatively affect gaming QoE throughout the evaluation

The Multiple Impacts of the Exchange Rate on Export Diversification

There is evidence that suggests that one of the channels through which the exchange rate could have an impact on growth is export product diversification. I distinguish between the variety and concentration dimensions of export diversification and review the theoretical and empirical literature relating these two dimensions to the level and the volatility of the exchange rate. Using disaggregated trade data for a long panel of countries, I investigate these relationships employing an econometric methodology that allows for heterogeneity of coefficients across countries, and discuss two sources of bias which are often overlooked. I find that the variety dimension of export diversification is positively related to a weaker exchange rate and negatively related to exchange rate volatility. These relationships seem to be stronger for goods with higher technological intensity. I do not find a clear relationship between the exchange rate and the concentration of exports

On the Variability of the Temperature Coefficients of mc-Si Solar Cells with Irradiance

The temperature sensitivity of silicon solar cells is in general assumed to be constant with irradiance in PV forecasting models, although it has been demonstrated experimentally that this is not true. In this study a theoretical model is established that describes the variation of the temperature coefficients of a silicon solar cell as a function of the irradiance. It is shown that the temperature sensitivity of the solar cell efficiency is decreasing with the irradiance and that the main reason for this behavior comes from the increase of the open-circuit voltage with light intensity. Moreover, a dependency of the cell's ideality factor on the irradiance has to be assumed to receive good modelling results that can be confirmed experimentally