889 research outputs found

    Die Persistenz von Institutionen - Hindernisse auf dem Weg zu einer nachhaltigen Flächennutzungspolitik in Deutschland

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    Sollen in Zukunft ambitionierte Ziele der nachhaltigen Flächennutzung erreicht werden, wie zum Beispiel das 30-Hektar-Ziel aus der Nachhaltigkeitsstrategie der rot-grünen Bundesregierung aus dem Jahre 2002, dann müssen politische Strategien gefunden werden, die es erlauben, weitgehende institutionelle Reformen zu verwirklichen. Die Voraussetzung dazu ist, vorhandene institutionelle Persistenzen und damit Reformblockaden zu identifizieren. Aufbauend auf theoretische Überlegungen widmet sich der Aufsatz einer Erörterung der Persistenz von Institutionen der Flächennutzung, um daraus politische Handlungsbeschränkungen und -spielräume ableiten zu können

    Optical second-harmonic effect of sol-gel inorganic-organic nanocomposites

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    Communications: Second-order nonlinear optically (NLO) active materials have promising technical applications in optoelectronic devices. A general problem in NLO-active polymeric systems is the decay of orientational order with time. Results are presented which show that using inorganic-organic composite materials produced by the sol-gel process as a rigid matrix for oriented Ă·(2) chromophores (Figure) may provide a means of overcoming this problem

    Coastal upwelling velocities inferred from helium isotope disequilibrium

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    In the framework of SOPRAN, two of the main gloabal Eastern Boundary Current Upwelling Systems (EBUS) have been investigated, off the coasts of Mauritania in the northern Atlantic and of Peru in the southern Pacific. The upwelling in the EBUS is driven by alongshore winds causing an offshore transport of surface waters. The upwelled water typically exhibits high concentrations of climate relevant gases such as CO2, N2O and halogenated compounds. The oceanic upwelling velocities, however, are too small (in the order of 10-5 m/s) to be measured directly. Here we use oceanic measurements of the helium-3/helium-4 isotopic ratio as an indirect means to infer these velocities. The water that upwells into the oceanic mixed layer from below is typically enriched in the lighter isotope helium-3. This excess of helium-3 originates from venting of primordial helium through hydrothermal activity. Helium data have been collected on four cruises within the coastal upwelling regions off Mauritania and Peru. Near the coast, the helium derived upwelling velocities are in good agreement with the wind driven flow calculated from Ekman theory. At some locations in the open ocean, however, the helium method results in much higher vertical velocities compared to the wind derived Ekman divergence. This enhanced upwelling might be attributed to eddy activity. Both advective and turbulent (derived from microstructure measurements) fluxes of nutrients into the mixed layer are determined. In coastal upwelling regions, these fluxes play a key role in fostering ocean primary productivity

    First year of practical experiences of the new Arctic AWIPEV-COSYNA cabled Underwater Observatory in Kongsfjorden, Spitsbergen

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    A combined year-round assessment of selected oceanographic data and a macrobiotic community assess- ment was performed from October 2013 to November 2014 in the littoral zone of the Kongsfjorden polar fjord system on the western coast of Svalbard (Norway). State of the art remote controlled cabled underwater observatory technology was used for daily vertical profiles of temperature, salinity, and turbidity together with a stereo-optical assessment of the macrobiotic community, including fish. The results reveal a distinct seasonal cycle in total species abundances, with a significantly higher total abundance and species richness dur- ing the polar winter when no light is available underwater compared to the summer months when 24 h light is available. During the winter months, a temporally highly segmented community was observed with respect to species occurrence, with single species dominating the winter community for re- stricted times. In contrast, the summer community showed an overall lower total abundance as well as a significantly lower number of species. The study clearly demonstrates the high potential of cable connected remote controlled digital sampling devices, especially in remote areas, such as po- lar fjord systems, with harsh environmental conditions and limited accessibility. A smart combination of such new dig- ital “sampling” methods with classic sampling procedures can provide a possibility to significantly extend the sampling time and frequency, especially in remote and difficult to access areas. This can help to provide a sufficient data density and therefore statistical power for a sound scientific analysis without increasing the invasive sampling pressure in ecolog- ically sensitive environments

    Quantification of liver iron content with CT—added value of dual-energy

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    Objective: To evaluate the value of dual-energy CT (DECT) with use of an iron-specific, three-material decomposition algorithm for the quantification of liver iron content (LIC). Methods: Thirty-one phantoms containing liver tissue, fat and iron were scanned with dual-source CT using single-energy at 120kV (SECT) and DECT at 80kV and 140kV. Virtual iron concentration (VIC) images derived from an iron-specific, three-material decomposition algorithm and measurements of fat-free and fat-containing phantoms were compared with the LIC and healthy liver tissue. Results: In the absence of fat significant linear correlations were found between LIC and HU from SECT and VIC (r = 0.984-0.997, p  0.632). Conclusions: Virtual iron concentration images generated from DECT provide added value for the quantification of LIC by disregarding the confounding effect of the natural variation of healthy liver attenuation and of co-existing liver fa

    Optical second-harmonic effect of sol-gel inorganic-organic nanocomposites

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    Communications: Second-order nonlinear optically (NLO) active materials have promising technical applications in optoelectronic devices. A general problem in NLO-active polymeric systems is the decay of orientational order with time. Results are presented which show that using inorganic-organic composite materials produced by the sol-gel process as a rigid matrix for oriented Ă·(2) chromophores (Figure) may provide a means of overcoming this problem

    Attraction of human monocytes by the neuropeptide secretoneurin

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    AbstractSecretoneurin is a newly discovered 33-amino-acid peptide derived from secretogranin II (chromogranin C) that is found in sensory afferent C-fibers. We show here that secretoneurin triggers the selective migration of human monocytes in vitro and in vivo. Combinations of secretoneurin with the sensory neuropeptides, substance P or somatostatin, synergistically stimulate such migration. The attraction of monocytes represents the first established function of secretoneurin as a sensory neuropeptide

    Deposits of disease-associated alpha-synuclein may be present in the dura mater in Lewy body disorders: implications for potential inadvertent transmission by surgery

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    Deposition of alpha-synuclein in the brain is a hallmark of Lewy body disorders. Alpha-synuclein has been considered to show prion-like properties. Prion diseases can be transmitted by the transplantation of cadaveric dura mater causing iatrogenic Creutzfeldt-Jakob disease. Recent observations of amyloid-β deposition in dural grafts support the seeding properties of amyloid-β. Here we assessed the presence of alpha-synuclein in dura mater samples as a potential transmissible seed source. We immunostained 32 postmortem dura mater samples; 16 cases with Lewy-body disorder (LBD) showing different pathology stages and 16 non-LBD cases for phosphorylated (Ser129) and disease-associated (5G4) alpha-synuclein. Disease-associated alpha-synuclein aggregates were identified in intradural nerve fibres and associated with a vessel in a single LBD-Braak stage 4 case. We conclude that alpha-synuclein is detectable, although rarely, in dura mater samples in patients with LBD. The risk of potential transmissibility of dural alpha-synuclein deserves assessment by complementary experimental studies
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