452 research outputs found

    The importance of play in early childhood education: A critical perspective on current policies and practices in Germany and Hong Kong

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    In order to reflect international reform movements in a system- and culture-comparative perspective, the following article investigates the early childhood education systems in Germany and in Hong Kong, with reference to the respective social and educational roots, pedagogical development lines and basic educational approaches. In addition, current developments, policies, and practices are described. The basic structural requirements of the respective systems will be presented, and the different reviews and implementation of international developments in Germany and Hong Kong will be explained. Special emphasis is placed on the importance of play in early childhood education. In this context, a current qualitative study of the authors is presented, which examined different perspectives on learning at play. The results of this exploratory study show that the interpretations and discussions of international reform approaches in different cultural settings are sometimes very different. The statements of the German and Chinese participants indicate that international developments are assessed primarily in the context of national educational traditions and structures. Against this backdrop, it is assumed that international reform movements despite some assimilations will have different effects in national education systems

    Fiber stiffness, pore size and adhesion control migratory phenotype of MDA-MB-231 cells in collagen gels

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    Cancer cell migration is influenced by cellular phenotype and behavior as well as by the mechanical and chemical properties of the environment. Furthermore, many cancer cells show plasticity of their phenotype and adapt it to the properties of the environment. Here, we study the influence of fiber stiffness, confinement, and adhesion properties on cancer cell migration in porous collagen gels. Collagen gels with soft fibers abrogate migration and promote a round, non-invasive phenotype. Stiffer collagen fibers are inherently more adhesive and lead to the existence of an adhesive phenotype and in general confined migration due to adhesion. Addition of TGF-beta lowers adhesion, eliminates the adhesive phenotype and increases the amount of highly motile amoeboid phenotypes. Highest migration speeds and longest displacements are achieved in stiff collagen fibers in pores of about cell size by amoeboid phenotypes. This elucidates the influence of the mechanical properties of collagen gels on phenotype and subsequently migration and shows that stiff fibers, cell sized pores, and low adhesion, are optimal conditions for an amoeboid phenotype and efficient migration

    Store-operated Ca2+ entry in primary murine lung fibroblasts is independent of classical transient receptor potential (TRPC) channels and contributes to cell migration

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    Stromal interaction molecules (STIM1, 2) are acting as sensors for Ca2+ in intracellular stores and activate Orai channels at the plasma membrane for store-operated Ca2+ entry (SOCE), while classical transient receptor potential (TRPC) channel mediate receptor-operated Ca2+ entry (ROCE). Several reports, however, indicate a role for TRPC in SOCE in certain cell types. Here, we analyzed Ca2+ influx and cell function in TRPC1/6-deficient (TRPC1/6(-/-)) and STIM1/2- deficient (STIM1/2(Delta pmLF)) primary murine lung fibroblasts (pmLF). As expected, SOCE was decreased in STIM1/2- deficient pmLF and ROCE was decreased in TRPC1/6(-/-) pmLF compared to control cells. By contrast, SOCE was not significantly different in TRPC1/6(-/-) pmLF and ROCE was similar in STIM1/2-deficient pmLF compared to Wt cells. Most interestingly, cell proliferation, migration and nuclear localization of nuclear factor of activated T-cells (NFATc1 and c3) were decreased after ablation of STIM1/2 proteins in pmLF. In conclusion, TRPC1/6 channels are not involved in SOCE and STIM1/2 deficiency resulted in decreased cell proliferation and migration in pmLF

    Estimation of Combustion Parameters from Engine Vibrations Based on Discrete Wavelet Transform and Gradient Boosting

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    An optimal control of the combustion process of an engine ensures lower emissions and fuel consumption plus high efficiencies. Combustion parameters such as the peak firing pressure (PFP) and the crank angle (CA) corresponding to 50% of mass fraction burned (MFB50) are essential for a closed-loop control strategy. These parameters are based on the measured in-cylinder pressure that is typically gained by intrusive pressure sensors (PSs). These are costly and their durability is uncertain. To overcome these issues, the potential of using a virtual sensor based on the vibration signals acquired by a knock sensor (KS) for control of the combustion process is investigated. The present work introduces a data-driven approach where a signal-processing technique, designated as discrete wavelet transform (DWT), will be used as the preprocessing step for extracting informative features to perform regression tasks of the selected combustion parameters with extreme gradient boosting (XGBoost) regression models. The presented methodology will be applied to data from two different spark-ignited, single cylinder gas engines. Finally, an analysis is obtained where the important features based on the model’s decisions are identified

    NOT JUST ANOTHER TYPE OF RESISTANCE – TOWARDS A DEEPER UNDERSTANDING OF SUPPORTIVE NON-USE

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    Research on information system (IS) adoption and resistance has accumulated substantial theoretical and managerial knowledge. Surprisingly, the paradox that end users support and at the same time resist use of an IS has received relatively little attention. The investigation of this puzzle, however, is important to complement our understanding of resistant behaviours and consequently to strengthen the explanatory power of extant theoretical constructs on IS resistance. We investigate an IS project within the healthcare sector in the UK in which end-users, who were heavily involved during the de-sign, implementation and roll out, expressed their support for the system, while simultaneously showing resistance. To examine this behaviour in detail, we applied Q methodology. As a result, we identified three different groups: (1) The convinced connector, waiting for collaborators. (2) The savvy explorer, sceptical about the tools’ benefits. (3) The ambivalent follower, overwhelmed by complexity. While the behaviour is similar across all three groups, the reasons for not using the system differ significantly. Based on these groups, as our main contribution, we explain the paradox of supportive non-use. We further add a fine grained understanding of supportive non-use to the existing types of IS resistance
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