396 research outputs found

    STTS 2.0. Guidelines für die Annotation von POS -Tags für Transkripte gesprochener Sprache in Anlehnung an das Stuttgart Tübingen Tagset (STTS)

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    Die Guidelines sind eine Erweiterung des STTS (Schiller et al. 1999) für die Annotation von Transkripten gesprochener Sprache. Dieses Tagset basiert auf der Annotation des FOLK-Korpus des IDS Mannheim (Schmidt 2014) und es wurde gegenüber dem STTS erweitert in Hinblick auf typisch gesprochensprachliche Phänomene bzw. Eigenheiten der Transkription derselben. Es entstand im Rahmen des Dissertationsprojekts „POS für(s) FOLK – Entwicklung eines automatisierten Part-of-Speech-Tagging von spontansprachlichen Daten“ (Westpfahl 2017 (i.V.))

    Highlighting Current Trends in Volunteered Geographic Information

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    Volunteered Geographic Information (VGI) is a growing area of research. This Special Issue aims to capture the main trends in VGI research based on 16 original papers, and distinguishes between two main areas, i.e., those that deal with the characteristics of VGI and those focused on applications of VGI. The topic of quality assessment and assurance dominates the papers on VGI characteristics, whereas application-oriented work covers three main domains: human behavioral analysis, natural disasters, and land cover/land use mapping. In this Special Issue, therefore, both the challenges and the potentials of VGI are addressed

    Skyrmion Lattice in a Chiral Magnet

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    Skyrmions represent topologically stable field configurations with particle-like properties. We used neutron scattering to observe the spontaneous formation of a two-dimensional lattice of skyrmion lines, a type of magnetic vortices, in the chiral itinerant-electron magnet MnSi. The skyrmion lattice stabilizes at the border between paramagnetism and long-range helimagnetic order perpendicular to a small applied magnetic field regardless of the direction of the magnetic field relative to the atomic lattice. Our study experimentally establishes magnetic materials lacking inversion symmetry as an arena for new forms of crystalline order composed of topologically stable spin states

    Long-range crystalline nature of the skyrmion lattice in MnSi

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    We report small angle neutron scattering of the skyrmion lattice in MnSi using an experimental set-up that minimizes the effects of demagnetizing fields and double scattering. Under these conditions the skyrmion lattice displays resolution-limited Gaussian rocking scans that correspond to a magnetic correlation length in excess of several hundred {\mu}m. This is consistent with exceptionally well-defined long-range order. We further establish the existence of higher-order scattering, discriminating parasitic double-scattering with Renninger scans. The field and temperature dependence of the higher-order scattering arises from an interference effect. It is characteristic for the long-range crystalline nature of the skyrmion lattice as shown by simple mean field calculations.Comment: 4 page

    Thermodynamic investigations in the precursor region of FeGe

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    High-resolution DC magnetization and AC-specific heat data of the cubic helimagnet FeGe have been measured as function of temperature and magnetic field. The magnetization data as well as the isothermal susceptibility data confirm the complexity of the magnetic phase diagram in the vicinity of the onset of long-rang magnetic order (Tc = 278.5 K) and the existence of a segmented A-phase region. Moreover, these data revealed independent and clear indications of phase boundaries and crossovers within the A-phase region. Together with the anomalies in the specific-heat data around Tc and at small magnetic fields (H < 600 Oe) a complex magnetic phase diagram of FeGe is obtained.Comment: Presented at the QCNP conference in Dreden, Germany, August 201

    Spin Transfer Torques in MnSi at Ultra-low Current Densities

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    Spin manipulation using electric currents is one of the most promising directions in the field of spintronics. We used neutron scattering to observe the influence of an electric current on the magnetic structure in a bulk material. In the skyrmion lattice of MnSi, where the spins form a lattice of magnetic vortices similar to the vortex lattice in type II superconductors, we observe the rotation of the diffraction pattern in response to currents which are over five orders of magnitude smaller than those typically applied in experimental studies on current-driven magnetization dynamics in nanostructures. We attribute our observations to an extremely efficient coupling of inhomogeneous spin currents to topologically stable knots in spin structures

    Theory of current-driven motion of Skyrmions and spirals in helical magnets

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    We study theoretically the dynamics of the spin textures, i.e., Skyrmion crystal (SkX) and spiral structure (SS), in two-dimensional helical magnets under external current. By numerically solving the Landau-Lifshitz-Gilbert equation, it is found that (i) the critical current density of the motion is much lower for SkX compared with SS in agreement with the recent experiment, (ii) there is no intrinsic pinning effect for SkX and the deformation of the internal structure of Skyrmion reduces the pinning effect dramatically, (iii) the Bragg intensity of SkX shows strong time-dependence as can be observed by neutron scattering experiment.Comment: 4 pages, 3 figure

    Indecent Bodies in Early Modern Visual Culture

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    The life-like depiction of the body became a central interest and defining characteristic of the European Early Modern period that coincided with the establishment of which images of the body were to be considered ʻdecentʼ and representable, and which disapproved, censored, or prohibited. Simultaneously, artists and the public became increasingly interested in the depiction of specific body parts or excretions. This book explores the concept of indecency and its relation to the human body across drawings, prints, paintings, sculptures, and texts. The ten essays investigate questions raised by such objects about practices and social norms regarding the body, and they look at the particular function of those artworks within this discourse. The heterogeneous media, genres, and historical contexts north and south of the Alps studied by the authors demonstrate how the alleged indecency clashed with artistic intentions and challenges traditional paradigms of the historiography of Early Modern visual culture

    Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures

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    Magnetic skyrmions are chiral spin structures with a whirling configuration. Their topological properties, nanometer size and the fact that they can be moved by small current densities have opened a new paradigm for the manipulation of magnetisation at the nanoscale. To date, chiral skyrmion structures have been experimentally demonstrated only in bulk materials and in epitaxial ultrathin films and under external magnetic field or at low temperature. Here, we report on the observation of stable skyrmions in sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero applied magnetic field. We use high lateral resolution X-ray magnetic circular dichroism microscopy to image their chiral N\'eel internal structure which we explain as due to the large strength of the Dzyaloshinskii-Moriya interaction as revealed by spin wave spectroscopy measurements. Our results are substantiated by micromagnetic simulations and numerical models, which allow the identification of the physical mechanisms governing the size and stability of the skyrmions.Comment: Submitted version. Extended version to appear in Nature Nanotechnolog
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