1,164 research outputs found

    Frankophonie im Wandel : Alphabetisierung fĂŒr frankophone Kanadier oder Migranten aus französischsprachigen LĂ€ndern?

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    Kanada ist ein offiziell zweisprachiges Land, in dem der Dualismus von Englisch und Französisch Geschichte hat. Die Frankophonie in Kanada ist in den letzten 20 Jahren in Bewegung geraten: Wirtschaftswandel und Migration aus französischsprachigen LĂ€ndern haben ihre soziale Struktur deutlich verĂ€ndert. Damit einher geht auch ein Wandel in der Politik: Die Basis-Alphabetisierung fĂŒr frankophone Erwachsene hat PrioritĂ€t, um damit die Voraussetzung fĂŒr bessere ökonomische Chancen zu schaffen. Dagegen rĂŒcken kulturelle Interessen, wie sie noch in den 1980er Jahren eine wesentliche Rolle fĂŒr die "Selbstidentifikation" der Frankophonen spielten, in den Hintergrund

    Topological invariants of classification problems

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    AbstractThere is a general agreement that problems which are highly complex in any naive sense are also difficult from the computational point of view. It is therefore of great interest to find invariants and invariant structures which measure in some respect the complexity of the given problem. The question which we are going to consider in the following paper are classification problems, the “computations” are described by questionnaires [3, 10] or, as they are called nowadays, by “branching programs” [11]. The “complexity” of the problem is measured by classical topological invariants (Betti numbers, Euler-PoincarĂ© characteristic) of topological structures (simplicial complexes, topological spaces)

    Convenient Homework Enhancing Assistance Technology

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    SP-0325: Participation to databases should not be made mandatory

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    Explainable deep learning models for biological sequence classification

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    Biological sequences - DNA, RNA and proteins - orchestrate the behavior of all living cells and trying to understand the mechanisms that govern and regulate the interactions among these molecules has motivated biological research for many years. The introduction of experimental protocols that analyze such interactions on a genome- or transcriptome-wide scale has also established the usage of machine learning in our field to make sense of the vast amounts of generated data. Recently, deep learning, a branch of machine learning based on artificial neural networks, and especially convolutional neural networks (CNNs) were shown to deliver promising results for predictive tasks and automated feature extraction. However, the resulting models are often very complex and thus make model application and interpretation hard, but the possibility to interpret which features a model has learned from the data is crucial to understand and to explain new biological mechanisms. This work therefore presents pysster, our open source software library that enables researchers to more easily train, apply and interpret CNNs on biological sequence data. We evaluate and implement different feature interpretation and visualization strategies and show that the flexibility of CNNs allows for the integration of additional data beyond pure sequences to improve the biological feature interpretability. We demonstrate this by building, among others, predictive models for transcription factor and RNA-binding protein binding sites and by supplementing these models with structural information in the form of DNA shape and RNA secondary structure. Features learned by models are then visualized as sequence and structure motifs together with information about motif locations and motif co-occurrence. By further analyzing an artificial data set containing implanted motifs we also illustrate how the hierarchical feature extraction process in a multi-layer deep neural network operates. Finally, we present a larger biological application by predicting RNA-binding of proteins for transcripts for which experimental protein-RNA interaction data is not yet available. Here, the comprehensive interpretation options of CNNs made us aware of potential technical bias in the experimental eCLIP data (enhanced crosslinking and immunoprecipitation) that were used as a basis for the models. This allowed for subsequent tuning of the models and data to get more meaningful predictions in practice

    Detection of longitudinal waves in resonance with capillary waves at the air-water interface by energy transfer.

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    Capillary (transverse) ripples are generated at a monolayer-covered air-water interface. Compression of the monolayer changes the surface dilatational modulus Δ and the reduced elasticity Δ/σ of the monolayer. When the reduced elasticity reaches a particular value, resonance between the capillary wave and the longitudinal wave should occur. Longitudinal waves (lateral oscillations, modulation of the average distances of the molecules) are detected by using energy transfer (Förster type) between dye molecules incorporated in the monolayer. Capillary ripples are detected by specular reflection of a laser beam from the water surface. The dependence of the longitudinal and the transverse wave characteristics on the area per molecule was investigated, and the resonance phenomenon was observed near the theoretical value of Δ/σ for the resonance condition
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