147 research outputs found
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Promoting learner autonomy through multiliteracy skills development in cross-institutional exchanges
This contribution presents findings from two empirical case studies, which followed a task-based telecollaborative learning format. Participants included student teacher trainees, tutors, and language learners from colleges/universities in Germany, Poland, the United Kingdom, and the United States. The projects aimed at promoting learner autonomy through awareness raising of modes and meaning-making online and multiliteracy skills development based on hands-on analysis of web resources and social networking tools.
It was hoped that this awareness would foster the teachers' own autonomy in virtual learning environments and enable them to design tasks which—in turn—would promote learner autonomy as understood by Palfreyman (2006): the informed use of a range of interacting resources in context. We argue that this awareness is reflected in enhanced multimodal communicative competence, i.e., “the ability to understand the combined potential of various modes for making meaning” (Royce, 2002, p. 92), and multiliteracy, with the latter allowing teachers and learners to realize the potential of blended and online only settings for language acquisition purposes. Ideally then, while becoming gradually more versed in multimodality and multiliteracy, learners can also take over more control and self-direct their own learning when working online (Benson, 2001) which are also characteristics of autonomy
A subcell-enriched Galerkin method for advection problems
In this work, we introduce a generalization of the enriched Galerkin (EG)
method. The key feature of our scheme is an adaptive two-mesh approach that, in
addition to the standard enrichment of a conforming finite element
discretization via discontinuous degrees of freedom, allows to subdivide
selected (e.g. troubled) mesh cells in a non-conforming fashion and to use
further discontinuous enrichment on this finer submesh. We prove stability and
sharp a priori error estimates for a linear advection equation by using a
specially tailored projection and conducting some parts of a standard
convergence analysis for both meshes. By allowing an arbitrary degree of
enrichment on both, the coarse and the fine mesh (also including the case of no
enrichment), our analysis technique is very general in the sense that our
results cover the range from the standard continuous finite element method to
the standard discontinuous Galerkin (DG) method with (or without) local subcell
enrichment. Numerical experiments confirm our analytical results and indicate
good robustness of the proposed method
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Approaches to researching digital-pedagogical competence development in VE-based teacher education
For the past two decades, Virtual Exchange (VE) has enjoyed increasing popularity in university education, including initial (language) teacher education programmes (O’Dowd, 2018). Collaborating online with colleagues and students from different cultural backgrounds and educational systems has allowed trainees to experience and reflect on issues related to technology and pedagogy in authentic linguistic and intercultural contexts. In 2017/2018, the Evaluating and Upscaling Telecollaborative Teacher Education (EVALUATE) project – an Erasmus+ funded European Policy Experimentation (EPE) – collected and analysed data from VEs across the curriculum involving over 1,000 participants at Initial Teacher Education (ITE) institutions in Europe and beyond.
Here, we specifically focus on the impact of VE on their digital-pedagogical competence development. Following a mixed method design we used the Technological PedagogicalContent Knowledge (TPACK) work of Mishra and Koehler (2006) and Schmidt et al. (2009) in a pre-post-test manner. These were complemented by qualitative content analysis of prompted diary entries at key stages during the exchanges to collect further evidence of existing and emerging digital-pedagogical skills among the trainees. Based on one case study of a German-Polish EVALUATE exchange we will exemplify the aforementioned research methods and associated challenges. We will illustrate the urgent need for initial and in-service teacher education that combines technology and pedagogy and argue for VE as an ideal context to this effect. Finally, we will demonstrate how the chosen research approach has contributed to providing the kind of evidence required by education administrators and policy makers for a systematic integration of VE into teacher education programmes
Enriched Galerkin method for the shallow-water equations
This work presents an enriched Galerkin (EG) discretization for the two-dimensional shallow-water equations. The EG finite element spaces are obtained by extending the approximation spaces of the classical finite elements by discontinuous functions supported on elements. The simplest EG space is constructed by enriching the piecewise linear continuous Galerkin space with discontinuous, element-wise constant functions. Similarly to discontinuous Galerkin (DG) discretizations, the EG scheme is locally conservative, while, in multiple space dimensions, the EG space is significantly smaller than that of the DG method. This implies a lower number of degrees of freedom compared to the DG method. The EG discretization presented for the shallow-water equations is well-balanced, in the sense that it preserves lake-at-rest configurations. We evaluate the method’s robustness and accuracy using various analytical and realistic benchmarks and compare the results to those obtained using the DG method. Finally, we briefly discuss implementation aspects of the EG method within our MATLAB / GNU Octave framework FESTUNG
C-fiber-related EEG-oscillations induced by laser radiant heat stimulation of capsaicin-treated skin
Nociceptive input reaches the brain via two different types of nerve fibers, moderately fast A-delta and slowly conducting C-fibers, respectively. To explore their distinct roles in normal and inflammatory pain we used laser stimulation of normal and capsaicin treated skin at proximal and distal arm sites in combination with time frequency transformation of electroencephalography (EEG) data. Comparison of phase-locked (evoked) and non-phase-locked (total) EEG to laser stimuli revealed three significant pain-related oscillatory responses. First, an evoked response in the delta-theta band, mediated by A-fibers, was reduced by topical capsaicin treatment. Second, a decrease of total power in the alpha-to-gamma band reflected both an A- and C-nociceptor-mediated response with only the latter being reduced by capsaicin treatment. Finally, an enhancement of total power in the upper beta band was mediated exclusively by C-nociceptors and appeared strongly augmented by capsaicin treatment. These findings suggest that phase-locking of brain activity to stimulus onset is a critical feature of A-delta nociceptive input, allowing rapid orientation to salient and potentially threatening events. In contrast, the subsequent C-nociceptive input exhibits clearly less phase coupling to the stimulus. It may primarily signal the tissue status allowing more long-term behavioral adaptations during ongoing inflammatory events that accompany tissue damage
COUPLED MAGNETO-MECHANICAL FINITE ELEMENT ANALYSIS OF A POWER TRANSFORMER IN SHORT CIRCUIT CONDITIONS
External short circuit is one of the most demanding load conditions a transformer can be
subjected to. Short circuit withstand capability of power transformers is therefore quintessentially
important in order to ensure the proper functioning of a power transformer during its lifetime. Accurate
calculation of the forces and stresses a transformer is subjected to during a short circuit is a prerequisite
for better, optimized design of the active part. Main focus of this paper is the investigation into dynamic
electromagnetic and mechanical behaviour of a transformer winding subject to an external short circuit.
For purposes of this simulation, a single-phase 100 MVA autotransformer active part was modelled using
ANSYS and NACS software. Particular areas of the winding were modelled to a greater degree of detail
in order to observe the effects of Lorentz forces during a short circuit on individual conductors. A transient
coupled magneto-mechanical simulation of the transformer under short circuit conditions was carried out.
When subject to dynamic short circuit forces, the winding discs exhibited a profoundly resonant
behaviour indicating a strong relationship between the natural frequency of the winding and the resulting
stresses and displacements incurred during a short circuit. It has been shown that the position of the yoke
changes the orientation and the distribution of the magnetic field vectors at the top and the bottom of the
winding, causing a non-uniform distribution of forces along the top discs of the winding. This non-uniform
distribution of forces along the circular shape of the winding conductor caused high stresses at the
positions within the winding which were previously considered to be under lower stress when calculated
using 3D static FEM and analytical methods
New insights on permafrost genesis and conservation in talus slopes based on observations at Flüelapass, Eastern Switzerland
The talus slope at Flüelapass was the first mountain permafrost study site in Switzerland in the 1970s and the presence of ice-rich permafrost at the foot of the slope has been investigated in the context of several studies focusing on the role of snow cover distribution. We review previously developed hypotheses and present new ones using various data sources, such as temperature measurements in boreholes, a subaquatic DEM generated from unmanned aerial system (UAS) photogrammetry, terrestrial laser scan measurements of snow depth, geophysical ground investigations and automatic time-lapse photography. From this combination of data sources together with observations in the field, an interesting sequence of geomorphologic processes is established at Flüelapass. As a result we show how mass wasting processes can initiate the genesis and long-term conservation of ice-rich permafrost at the base of a talus slope
Influence of the autotaxin-lysophosphatidic acid axis on cellular function and cytokine expression in different breast cancer cell lines
Previous studies provide high evidence that autotaxin (ATX)-lysophosphatidic acid (LPA) signaling through LPA receptors (LPAR) plays an important role in breast cancer initiation, progression, and invasion. However, its specific role in different breast cancer cell lines remains to be fully elucidated to offer improvements in targeted therapies. Within this study, we analyzed in vitro the effect of LPA 18:1 and the LPAR1, LPAR3 (and LPAR2) inhibitor Ki16425 on cellular functions of different human breast cancer cell lines (MDA-MB-231, MDA-MB-468, MCF-7, BT-474, SKBR-3) and the human breast epithelial cell line MCF-10A, as well as Interleukin 8 (IL-8), Interleukin 6 (IL-6) and tumor necrosis factor (TNF)-alpha cytokine secretion after LPA-incubation. ATX-LPA signaling showed a dose-dependent stimulatory effect especially on cellular functions of triple-negative and luminal A breast cancer cell lines. Ki16425 inhibited the LPA-induced stimulation of triple-negative breast cancer and luminal A cell lines in variable intensity depending on the functional assay, indicating the interplay of different LPAR in those assays. IL-8, IL-6 and TNF-alpha secretion was induced by LPA in MDA-MB-468 cells. This study provides further evidence about the role of the ATX-LPA axis in different breast cancer cell lines and might contribute to identify subtypes suitable for a future targeted therapy of the ATX-LPA axis
Flow cytometric measurement of STAT5 phosphorylation in cytomegalovirus-stimulated T cells
Cytomegalovirus (CMV)-specific T cells expand with CMV reactivation and are probably prerequisite for control and protection. Given the critical role STAT5A phosphorylation (pSTAT5A) in T cell proliferation, this study presents a simple and sensitive flow cytometric-based pSTAT5A assay to quickly identify CMV-specific T cell proliferation. We determined pSTAT5A in T cells treated with CMV-specific peptide mix (pp65 + IE1 peptides) from 20 healthy adult subjects and three immunodeficient patients with CARMIL-2 mutation. After stimulation, the percentage of pSTAT5A+ T cells in CMV-seropositive (CMV+) subjects significantly increased from 3.0% ± 1.9% (unstimulated) to 11.4% ± 5.9% (stimulated) for 24 h. After 7 days of stimulation, the percentage of expanded T cells amounted to 26% ± 17.2%. Conversely, the percentage of pSTAT5A+ T cells and T cell proliferation from CMV-seronegative (CMV−) subjects hardly changed (from 3.0% ± 1.3% to 3.7% ± 1.8% and from 4.3% ± 2.1% to 5.7% ± 1.7%, respectively). We analyzed the correlation between the percentage of pSTAT5A+ T cells versus (1) CMV-IgG concentrations versus (2) the percentage of expanded T cells and versus (3) the percentage of initial CMV-specific T cells. In immunodeficient patients with CARMIL-2 mutation, CMV-specific pSTAT5A and T cell proliferation were completely deficient. In conclusion, flow cytometric-based pSTAT5A assay represents an appropriate tool to quickly identify CMV-specific T cell proliferation and helps to understand dysfunctions in controlling other pathogens. Flow cytometric-based pSTAT5A assay may be a useful test in clinical practice and merits further validation in large studies
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