231 research outputs found

    Hugo Portisch: So sah er Brasilien

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    In dieser Arbeit sollen die Reiseberichte/Reisereportage von Hugo Portisch, die sich mit Brasilien beschĂ€ftigen, einer eingehenden Analyse unterzogen werden. Ziel dieser Arbeit ist es heraus zu finden, ob Hugo Portisch in seinen Reportagen das gĂ€ngige „Brasilien Bild“ bedient, oder ob er sich neuer und nicht ganz so populĂ€rer Themen annimmt. Um diese Fragen zu beantworten, wurden die Arbeiten von Hugo Portisch in direkten Vergleich mit Artikeln und Reportagen zum Thema „Brasilien“ aus österreichischen Printmedien und mit dem Ergebnis einer Umfrage zum gleichen Thema gestellt

    Efficient sampling methodologies for lake littoral invertebrates in compliance with the European Water Framework Directive

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    Lake shores are characterised by a high natural variability, which is increasingly threatened by a multitude of anthropogenic disturbances including morphological alterations to the littoral zone. The European Water Framework Directive (EU WFD) calls for the assessment of lake ecological status by monitoring biological quality elements including benthic macroinvertebrates. To identify cost- and time-efficient sampling strategies for routine lake monitoring, we sampled littoral invertebrates in 32 lakes located in different geographical regions in Europe. We compared the efficiency of two sampling methodologies, defined as habitat-specific and pooled composite sampling protocols. Benthic samples were collected from unmodified and morphologically altered shorelines. Variability within macroinvertebrate communities did not differ significantly between sampling protocols across alteration types, lake types and geographical regions. Community composition showed no significant differences between field composite samples and artificially generated composite samples, and correlation coefficients between macroinvertebrate metrics calculated with both methods and a predefined morphological stressor index were similar. We conclude that proportional composite sampling represents a time- and cost-efficient method for routine lake monitoring as requested under the EU WFD, and may be applied across various European geographical regions

    Historical Patterns of Anthropogenic Impacts on Freshwaters in the Berlin-Brandenburg Region

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    Since humans are preferentially settling in flood plains they often influence freshwater systems intensely. The first signs of anthropogenic impacts on surface waters in the Berlin-Brandenburg region are approximately 3000 years old. Considering the multiple and intense human uses of surface waters in this region, we analysed when, how and to which extent regional rivers and streams became impacted by dams, water mills and fish weirs resulting in changes in morphology, hydrology and ecological functioning. We hypothesise that the development and growth of cities in this region necessitated (1) efficient navigability of rivers linking them, (2) efficient use of hydropower resources for mills, and (3) significant pollution of surface waters especially with the beginning of industrial development. We analyse these hypotheses by means of three regional examples and delineate the effects of human uses on selected surface water bodies. Understanding the effects of these historic modifications of surface water supports the identification of options for a sustainable use of surface waters that are currently still subjected to multiple uses but face a significant decrease in discharge due to climate change

    Relative impacts of morphological alteration to shorelines and eutrophication on littoral macroinvertebrates in Mediterranean lakes

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    Development of effective methods for assessing the ecological status of lakes based on littoral benthic fauna has been hampered by the lack of quantitative data on the relative impacts of key pressures on the benthic community. We used variance partitioning at 126 sites belonging to 14 natural Mediterranean lakes to analyze the pure and shared effects of eutrophication, morphological alterations, microhabitat type, lake morphometry and geographic position on the littoral macroinvertebrate community. The spatial arrangement of the sampling sites was responsible for 9.1% of the total variance in littoral benthic community composition, lake morphometry accounted for 4.3% of variation, and microhabitat type accounted for 3.9%. Communities appeared to be affected primarily by morphological alterations to lake shorelines, and their impact was 2.5 times as important as that of eutrophication. The structure of littoral benthic communities was governed by processes acting at several spatial scales from region to lake scale. Thus, several pressures and the various spatial scales at which these act should be taken into account when implementing methods of assessing lake ecological condition based on littoral benthic invertebrates. Region-specific methods for subalpine and volcanic lakes might enhance the validity of assessment of results of morphological alterations and improve management of those water resources

    A Lightweight AV System for Providing a Faithful and Spatially Manipulable Visual Hand Representation

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    Session: Developing new tools and technologies - Abstracts to be published in a regular issue of the journal Cyberpsychology, Behavior and Social Networking (indexed in MedLine and PsychInfo): http://online.liebertpub.com/loi/CYBERInternational audienceThis paper introduces the technical foundations of a system designed to embed a lightweight, faithful and spatially manipulable representation of the user's hand into an otherwise virtual world (aka Augmented Virtuality, AV). A highly intuitive control during pointing-like near space interaction can be provided to the user as well as a very flexible means to experimenters in a variety of non-medical and medical contexts. Our approach essentially relies on stereoscopic video seethrough Augmented Reality (AR) technology and a generic, extendible framework for managing 3D visual hand displacements. Research from human-computer interaction, perception and motor control has contributed to the elaboration of our proposal which combines a) acting in co-location, b) avoiding occlusion violations by assuring a correct scene depth ordering and c) providing a convincing visual feedback of the user's hand. We further present two cases in which this system has already successfully been used and then line out some other applications that we think are promising, for instance, in the fields of neuromotor rehabilitation and experimental neuroscience

    Advanced Gust Load Alleviation using Dynamic Control Allocation

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    Active control techniques play a key role in today's aircraft developments to reduce structural loads during gust encounter and thereby enable highly fuel-efficient aircraft designs. The performance of such gust load alleviation (GLA) systems, however, is often limited by physical limitations in the actuation system. In this paper, a novel GLA control approach is presented which exploits actuator redundancies to avoid performance degradations when individual actuators are driven to their limits or become faulty. To that end, a baseline controller for damping loads-dominating aeroelastic modes is extended with a dynamic control allocation system for handling constrained actuators. Thereby, virtual control inputs, generated for a targeted aeroelastic mode control, are distributed to the actual control inputs in an optimal way. To do so, a convex optimization problem is formulated which is solved in real time with the goal to minimize performance degradations due to actuator constraints. The effectivity of the presented GLA controller is experimentally validated on a highly flexible wing in a wind tunnel considering different actuator constraints and gust excitations at multiple airspeeds

    Impacts of existing and planned hydropower dams on river fragmentation in the Balkan Region

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    The Balkan region has some of the best conserved rivers in Europe, but is also the location of ~3000 planned hydropower dams that are expected to help decarbonise energy production. A conflict between policies that promote renewable hydropower and those that prioritise river conservation has ensued, which can only be resolved with the help of reliable information. Using ground-truthed barrier data, we analysed the extent of current longitudinal river fragmentation in the Balkan region and simulated nine dam construction scenarios that varied depending on the number, location and size of the planned dams. Balkan rivers are currently fragmented by 83,017 barriers and have an average barrier density of 0.33 barriers/km after correcting for barrier underreporting; this is 2.2 times lower than the mean barrier density found across Europe and serves to highlight the relatively unfragmented nature of these rivers. However, our analysis shows that all simulated dam construction scenarios would result in a significant loss of connectivity compared to existing conditions. The largest loss of connectivity (−47 %), measured as reduction in barrier-free length, would occur if all planned dams were built, 20 % of which would impact on protected areas. The smallest loss of connectivity (−8 %) would result if only large dams (>10 MW) were built. In contrast, building only small dams (<10 MW) would cause a 45 % loss of connectivity while only contributing 32 % to future hydropower capacity. Hence, the construction of many small hydropower plants will cause a disproportionately large increase in fragmentation that will not be accompanied by a corresponding increase in hydropower. At present, hydropower development in the Balkan rivers does not require Strategic Environmental Assessment, and does not consider cumulative impacts. We encourage planners and policy makers to explicitly consider trade-offs between gains in hydropower and losses in river connectivity at the river basin scale.Impacts of existing and planned hydropower dams on river fragmentation in the Balkan RegionpublishedVersio

    Floodplain management in temperate regions : is multifunctionality enhancing biodiversity?

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    Background: Floodplains are among the most diverse, dynamic, productive and populated but also the most threatened ecosystems on Earth. Threats are mainly related to human activities that alter the landscape and disrupt fluvial processes to obtain benefits related to multiple ecosystem services (ESS). Floodplain management therefore requires close coordination among interest groups with competing claims and poses multi-dimensional challenges to policy-makers and project managers. The European Commission proposed in its recent Biodiversity Strategy to maintain and enhance European ecosystems and their services by establishing green infrastructure (GI). GI is assumed to provide multiple ecosystem functions and services including the conservation of biodiversity in the same spatial area. However, evidence for biodiversity benefits of multifunctional floodplain management is scattered and has not been synthesised. Methods/design: This protocol specifies the methods for conducting a systematic review to answer the following policy-relevant questions: a) what is the impact of floodplain management measures on biodiversity; b) how does the impact vary according to the level of multifunctionality of the measures; c) is there a difference in the biodiversity impact of floodplain management across taxa; d) what is the effect of the time since implementation on the impact of the most important measures; and e) are there any other factors that significantly modify the biodiversity impact of floodplain management measures? Within this systematic review we will assess multifunctionality in terms of ESS that are affected by an implemented intervention. Biodiversity indicators included in this systematic review will be related to the diversity, richness and abundance of species, other taxa or functional groups. We will consider if organisms are typical for and native to natural floodplain ecosystems. Specific inclusion criteria have been developed and the wide range of quality of primary literature will be evaluated with a tailor-made system for assessing susceptibility to bias and the reliability of the studies. The review is intended to bridge the science-policy interface and will provide a useful synthesis of knowledge for decision-makers at all governance levels

    Quantitative Imaging of D-2-Hydroxyglutarate in Selected Histological Tissue Areas by a Novel Bioluminescence Technique

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    Patients with malignant gliomas have a poor prognosis with average survival of less than 1 year. Whereas in other tumor entities the characteristics of tumor metabolism are successfully used for therapeutic approaches, such developments are very rare in brain tumors, notably in gliomas. One metabolic feature characteristic of gliomas, in particular diffuse astrocytomas and oligodendroglial tumors, is the variable content of D-2-hydroxyglutarate (D2HG), a metabolite that was discovered first in this tumor entity. D2HG is generated in large amounts due to various "gain-of-function" mutations in the isocitrate dehydrogenases IDH1 and 1DH2. Meanwhile, D2HG has been detected in several other tumor entities, including intrahepatic bile-duct cancer, chondrosarcoma, acute myeloid leukemia, and angioimmunoblastic T-cell lymphoma. D2HG is barely detectable in healthy tissue (<0.1 mM), but its concentration increases up to 35 mM in malignant tumor tissues. Consequently, the "oncometabolite" D2HG has gained increasing interest in the field of tumor metabolism. To facilitate its quantitative measurement without loss of spatial resolution at a microscopical level, we have developed a novel bioluminescence assay for determining D2HG in sections of snap-frozen tissue. The assay was verified independently by photometric tests and liquid chromatography/mass spectrometry. The novel technique allows the microscopically resolved determination of D2HG in a concentration range of 0-10 mu mol/g tissue (wet weight). In combination with the already established bioluminescence imaging techniques for ATP, glucose, pyruvate, and lactate, the novel D2HG assay enables a comparative characterization of the metabolic profile of individual tumors in a further dimension
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