167 research outputs found

    Increasing Evapotranspiration on Extensive Green Roofs by Changing Substrate Depths, Construction, and Additional Irrigation

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    Urban environments are characterized by dense development and paved ground with reduced evapotranspiration rates. These areas store sensible and latent heat, providing the base for typical urban heat island effects. Green roof installations are one possible strategy to reintroduce evaporative surfaces into cities. If green roofs are irrigated, they can contribute to urban water management and evapotranspiration can be enhanced. As part of two research projects, lysimeter measurements were used to determine the real evapotranspiration rates on the research roof of the University of Applied Sciences in Neubrandenburg, Germany. In this paper, we address the results from 2017, a humid and cool summer, and 2018, a century summer with the highest temperatures and dryness over a long period of time, measured in Northeast Germany. The lysimeter measurements varied between the normal green roof layer (variation of extensive green roof constructions) and a special construction with an extra retention layer and damming. The results show that the average daily evapotranspiration rates can be enhanced from 3 to 5 L/m2/day under optimized conditions. A second test on a real green roof with irrigation was used to explain the cooling effects of the surface above a café building in Berlin

    Three soil bacterial communities from an archaeological excavation site of an ancient coal mine near Bennstedt (Germany) characterized by 16S r-RNA sequencing

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    This metagenomics investigation of three closely adjacent sampling sites from an archaeological excavation of a pre-industrial coal mining exploration shaft provides detailed information on the composition of the local soil bacterial communities. The observed significant differences between the samples, reflected in the 16S r-RNA analyses, were consistent with the archaeologically observed situation distinguishing the coal seam, the rapidly deposited bright sediment inside an exploration shaft, and the topsoil sediment. In general, the soils were characterized by a dominance of Proteobacteria , Actinobacteria , Acidobacteria , and Archaea , whereas the coal seam was characterized by the highest proportion of Proteobacteria ; the topsoil was characterized by very high proportions of Archaea —in particular, Nitrosotaleaceae —and Acidobacteria, mainly of Subgroup 2. Interestingly, the samples of the fast-deposited bright sediment showed a rank function of OTU abundances with disproportional values in the lower abundance range. This could be interpreted as a reflection of the rapid redeposition of soil material during the refilling of the exploration shaft in the composition of the soil bacterial community. This interpretation is supported by the observation of a comparatively high proportion of reads relating to bacteria known to be alkaliphilic in this soil material. In summary, these investigations confirm that metagenomic analyses of soil material from archaeological excavations can provide valuable information about the local soil bacterial communities and the historical human impacts on them

    Lebensqualität als Bewertungsparameter für Lebensrisiken

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    The paper focuses on risk presentation with regard to the loss of human life. Several measures of risk, such as F-N diagrams, the probability of loss of life and days of lost life expectancy are introduced. All of these measures are specialised for different types of loss. In addition, quality-of-life parameters can be understood as measures of risk. In contrast to the afore-mentioned measures of risk, quality-of-life parameters are able to cover the entire field of risk to human life. If this is true, then the efficiency of all safety actions can be compared, regardless of their specific field. This would also permit competition among safety actions across an entire society and should yield not only improvements for safety, but also an increase in the quality of life within that society.Der folgende Beitrag befasst sich mit der Darstellung von Risiken für Menschen. Dazu werden verschiedene Risikoparameter, wie Sterbewahrscheinlichkeiten, F-N-Diagramme und das Konzept der verlorenen Lebensjahre, vorgestellt. Weiterhin können Lebensqualitätsparameter, die in den unterschiedlichsten Fachbereichen entwickelt wurden, als Risikoparameter verstanden werden. Während die zuerst genannten Risikoparameter im Wesentlichen auf einen Aspekt eines Schadens ausgerichtet sind, können Lebensqualitätsparameter alle Formen von Verlusten oder Nachteilen erfassen. Damit wird der Vergleich von risikoverringernden Maßnahmen unabhängig vom Fachbereich einer Maßnahme möglich. Ein solcher Ansatz erlaubt den Wettbewerb aller Schutzmaßnahmen innerhalb einer Gesellschaft und müsste zu einer Erhöhung der Sicherheit und der Lebensqualität führen

    Comparison of the antioxidant potential in urine, saliva and skin

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    Aim: Free radicals, oxidative stress and their possible consequences for health are becoming increasingly important in modern medicine. Reactive species influence the organism, potentially causing oxidative cell damage. They can be produced by exogenous sources, or be a product of a variety of not only physiological metabolic processes, such as immune response, but also pathological processes. The antioxidant protection system protects the organism from oxidative damage caused by reactions producing an excess of free radicals. The analysis of antioxidant potential (AOP) is therefore becoming increasingly important for the diagnosis of individual vitality

    Integrated laser-diode voltage driver for 20-Gb/s optical systems using 0.3- μm gate length quantum-well HEMT's

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    An integrated laser-diode voltage driver (LDVD) making use of enhancement/depletion AlGaAs-GaAs quantum-well high electron mobility transistors (QW HEMTs) with gate lengths of 0.3 μm has been developed. Its large signal bandwidth is 12 GHz. Eye diagrams of the output signal at bit rates up to 8 Gb/s show an opening similar to that of the input signal. Supporting material is given indicating that the LDVD might operate at bit rates up to 20 Gb/s. The maximum output current is over 90 mA; the maximum modulation voltage of 800 mV corresponds to 40-mA modulation current for a laser diode with 20-Ω dynamic resistance. The power consumption is less than 500 mW

    8.2 GHz bandwidth monolithic integrated optoelectronic receiver using MSM photodiode and 0.5 μm recessed-gate AlGaAs/GaAs HEMTs

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    An 8.2 GHz bandwidth monolithic optoelectronic receiver consisting of an MSM photodiode, a transimpedance amplifier, and a 50 Omega output buffer has been fabricated using an enhancement/depletion 0.5 μm recessed-gate AlGaAs/GaAs HEMT process. Successful operation at data rates up to 10 Gbit/s has been demonstrated

    Zurich Consensus: Statement of German Experts on St. Gallen Conference 2011 on Primary Breast Cancer (Zurich 2011)

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    Every 2 years, the International Consensus Conference on the Treatment of Primary Breast Cancer takes place in St. Gallen. Given that the concept of the St. Gallen Consensus Conference mainly reflects an international opinion, it appears useful to adapt the results of the vote for everyday therapy in Germany. A German working group comprising 28 breast cancer experts, amongst whom there are 3 members of the international St. Gallen panel, has therefore commented on this year's St. Gallen Consensus Conference (2011) from the German viewpoint. The focus of interest of this year's St. Gallen Conference was tumour biology as the starting point for decisions regarding individual therapy. There was an intensive discussion in relation to the clinical relevance of predictive and prognostic factors and possible consequences for decisions regarding therapy. Therefore, questions concerning the indication for adjuvant chemotherapy focused especially on the significance of the molecular phenotype of the tumour. In addition, important points for discussion were also the value of complete axillary dissection and the use of accelerated complete breast irradiation

    An 18-34-GHz dynamic frequency divider based on 0.2-μm AlGaAs/GaAs/AlGaAs quantum-well transistors

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    The design and performance of a dynamic frequency divider was presented. This digital IC demonstrates the ability of the authors' AlGaAs/GaAs/AlGaAs quantum-well FETs with gate lengths of 0.2 μm. Stable operation was achieved in the frequency range from 18 GHz up to 34 GHz with a power consumption of 250 mW. To the authors' knowledge, this is the best result ever reported for HEMT circuits, and is similar to the frequency limit achieved by use of AlGaAs/GaAs HBTs
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