487 research outputs found

    Complexity in Education for Sustainable Consumption—An Educational Data Mining Approach using Mysteries

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    Systems thinking is one of the skills necessary for sustainable behavior, especially regarding sustainable consumption. Students are faced with complexity and uncertainty while taking part in it and other daily life aspects. There is a need to foster their competence in this field. From a classroom point of view, the mystery method is an example for implementing education for sustainable consumption and working with complex and uncertain content. With the mystery method students construct an influence diagram, which consists of concepts and requires several skills, especially in decision-making. Using these diagrams as a form of assessment is desirable but also very difficult, because of the mentioned complexity and uncertainty that is part of the task itself. The study presented here tackles this problem by creating an expert based reference diagram that has been constructed with the help of educational data mining. The result shows that it is possible to derive such a reference even if parts remain ambiguous due to the inherent complexity. The reference may now be used to assess students’ systems thinking abilities, which will be undertaken in future research. Beside this, the reference can be used as a reflective tool in lessons, so students can compare their own content knowledge and discuss differences to the experts’ reference

    The Mystery Method Reconsidered—A Tool for Assessing Systems Thinking in Education for Sustainable Development

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    InïŹ‚uence diagrams, derived from the mystery method as its learning output, represent an externalization of systems thinking and are, therefore, valid to research; so far they have not been conceptualized in the research literature for teaching systems thinking in education for sustainable development. In this study, 31 of those diagrams are confronted with (1) three diïŹ€erent expert references, in (2) two diïŹ€erent ways, by (3) three diïŹ€erent scoring systems to determine which evaluation option is both valid and easy to implement. As a benchmark, the diagrams’ diameters are used, which allows statements about the quality of the maps/diagrams in general. The results show that, depending on the combination of variables that play a role in the evaluation (1, 2, 3), the quality of the inïŹ‚uence diagram becomes measurable. However, strong diïŹ€erences appear in the various evaluation schemes, which can be explained by each variable’s peculiarities. Overall, the tested methodology is eïŹ€ective, but will need to be sharpened in the future. The results also oïŹ€er starting points for future research to further deepen the path taken here

    Sialic Acid Utilisation and Synthesis in the Neonatal Rat Revisited

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    Background: Milk is the sole source of nutrients for neonatal mammals and is generally considered to have co-evolved with the developmental needs of the suckling newborn. One evolutionary conserved constituent of milk and present on many glycoconjugates is sialic acid. The brain and colon are major sites of sialic acid display and together with the liver also of synthesis. Methodology/Principal Findings: In this study we examined in rats the relationship between the sialic acid content of milk and the uptake, utilization and synthesis of sialic acid in suckling pups. In rat milk sialic acid was found primarily as 39sialyllactose and at highest levels between 3 and 10 days postpartum and that decreased towards weaning. In the liver of suckling pups sialic acid synthesis paralleled the increase in milk sialic acid reaching and keeping maximum activity from postnatal day 5 onwards. In the colon, gene expression profiles suggested that a switch from sialic acid uptake and catabolism towards sialic acid synthesis and utilization occurred that mirrored the change of sialic acid in milk from high to low expression. In brain sialic acid related gene expression profiles did not change to any great extent during the suckling period. Conclusions/Significance: Our results support the views that (i) when milk sialic acid levels are high, in the colon this sialic acid is catabolized to GlcNAc that in turn may be used as such or used as substrate for sialic acid synthesis and (ii) when milk sialic acid levels are low the endogenous sialic acid synthetic machinery in colon is activated

    Wave curves: Simulating Lagrangian water waves on dynamically deforming surfaces

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    We propose a method to enhance the visual detail of a water surface simulation. Our method works as a post-processing step which takes a simulation as input and increases its apparent resolution by simulating many detailed Lagrangian water waves on top of it. We extend linear water wave theory to work in non-planar domains which deform over time, and we discretize the theory using Lagrangian wave packets attached to spline curves. The method is numerically stable and trivially parallelizable, and it produces high frequency ripples with dispersive wave-like behaviors customized to the underlying fluid simulation

    Towards an analytical description of active microswimmers in clean and in surfactant-covered drops

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    Geometric confinements are frequently encountered in the biological world and strongly affect the stability, topology, and transport properties of active suspensions in viscous flow. Based on a far-field analytical model, the low-Reynolds-number locomotion of a self-propelled microswimmer moving inside a clean viscous drop or a drop covered with a homogeneously distributed surfactant, is theoretically examined. The interfacial viscous stresses induced by the surfactant are described by the well-established Boussinesq-Scriven constitutive rheological model. Moreover, the active agent is represented by a force dipole and the resulting fluid-mediated hydrodynamic couplings between the swimmer and the confining drop are investigated. We find that the presence of the surfactant significantly alters the dynamics of the encapsulated swimmer by enhancing its reorientation. Exact solutions for the velocity images for the Stokeslet and dipolar flow singularities inside the drop are introduced and expressed in terms of infinite series of harmonic components. Our results offer useful insights into guiding principles for the control of confined active matter systems and support the objective of utilizing synthetic microswimmers to drive drops for targeted drug delivery applications.Comment: 19 pages, 7 figures. Regular article contributed to the Topical Issue of the European Physical Journal E entitled "Physics of Motile Active Matter" edited by Gerhard Gompper, Clemens Bechinger, Holger Stark, and Roland G. Winkle

    Far‐Ranging Impact of Mountain Waves Excited Over Greenland on Stratospheric Dehydration and Rehydration

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    In situ observations of reduced stratospheric water vapor combined with those of ice particle formation are rarely conducted. On the one hand, they are essential to broaden our knowledge about the formation of polar stratospheric clouds (PSCs). On the other hand, the observed proles allow the comparison with global circulation models

    A quantitative analysis of stratospheric HCl, HNO3, and O3 in the tropopause region near the subtropical jet

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    The effects of chemical two-way mixing on the Extratropical Transition Layer (ExTL) near the subtropical jet are investigated by stratospheric tracer-tracer correlations. To this end, in situ measurements were performed west of Africa (25–32◩N) during the Transport and Composition of the Upper Troposphere Lower Stratosphere (UTLS)/Earth System Model Validation (TACTS/ESMVal) mission in August/September 2012. The Atmospheric chemical Ionization Mass Spectrometer sampling HCl and HNO3 was for the first time deployed on the new German High Altitude and Long range research aircraft (HALO). Measurements of O3, CO, European Centre for Medium-Range Weather Forecasts (ECMWF) analysis, and the tight correlation of the unambiguous tracer HCl to O3 and HNO3 in the lower stratosphere were used to quantify the stratospheric content of these species in the ExTL. With increasing distance from the tropopause, the stratospheric content increased from 10% to 100% with differing profiles for HNO3 and O3. Tropospheric fractions of 20% HNO3 and 40% O3 were detected up to a distance of 30 K above the tropopause
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