674 research outputs found

    Complex THz and DC inverse spin Hall effect in YIG/Cu1x_{1-x}Irx_{x} bilayers across a wide concentration range

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    We measure the inverse spin Hall effect of Cu1x_{1-x}Irx_{x} thin films on yttrium iron garnet over a wide range of Ir concentrations (0.05x0.70.05 \leqslant x \leqslant 0.7). Spin currents are triggered through the spin Seebeck effect, either by a DC temperature gradient or by ultrafast optical heating of the metal layer. The spin Hall current is detected by, respectively, electrical contacts or measurement of the emitted THz radiation. With both approaches, we reveal the same Ir concentration dependence that follows a novel complex, non-monotonous behavior as compared to previous studies. For small Ir concentrations a signal minimum is observed, while a pronounced maximum appears near the equiatomic composition. We identify this behavior as originating from the interplay of different spin Hall mechanisms as well as a concentration-dependent variation of the integrated spin current density in Cu1x_{1-x}Irx_{x}. The coinciding results obtained for DC and ultrafast stimuli show that the studied material allows for efficient spin-to-charge conversion even on ultrafast timescales, thus enabling a transfer of established spintronic measurement schemes into the terahertz regime.Comment: 12 pages, 4 figure

    Digitale Identitäten - Identitätsbildung im Internet und deren Auswirkung auf politische Partizipation

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    Die Verbreitung des Internets und die digitale Durchdringung aller Lebensbereiche hat Einfluss auf die Identitätsbildung von Individuen und Gruppen. Dabei spielt die Einführung von digitalen Authentifizierungsmechanismen und -karten wie der neue digitale Personalausweis (nPA) eine zunehmend wichtige Rolle.Dies kann ebenfalls die politische Partizipationsbereitschaft des Bürgers tangieren. Partizipation als Teilhabe am inhaltlichen Diskurs auf Bundesebene in Deutschland benötigt dabei Beteiligungsangebote der Parteien, welche den Bürger mit einbindet. Elektronische digitale Authentifikationsmechanismen könnten dabei politischen Aussagen der Bürger mehr Gewicht und damit Legitimität verleihen oder auch die Partizipation durch Bedrohungen im Datenschutz behindern. Im Ergebnis ist eine inhaltliche Partizipation des Bürgers über das Internet bei den Parteien bisher nur selten möglich, ein Diskurs über die Nutzung von authentifizierten elektronischen Beteiligungsverfahren wie dem nPA ist bei den meisten Parteien noch nicht feststellbar

    Mind the Gap - Über die Berücksichtigung von Finanzbildungsinhalten im Lehrstoff österreichischer Pflichtschulen

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    Da Finanzbildung im Idealfall schon bei Kindern und Jugendlichen ansetzt (vgl. Grohmann/Menkhoff 2015; Whitebread/Bingham 2013), hat eine Sub-Arbeitsgruppe des International Network on Financial Education (INFE), unter Mitarbeit der Österreichischen Nationalbank (OeNB), einen umfangreichen Katalog an Core Competencies für die Finanzkompetenz von Jugendlichen veröffentlicht (vgl. OECD 2015b). Dieser legt fest, welches Wissen und welche Fähigkeiten Kinder und Jugendliche im Alter von 15-18 Jahren in Bezug auf finanzielle Fragen haben sollten. Angesichts der hohen Relevanz von Finanzbildung stellt sich ausgehend von diesem Rahmenwerk die Frage, inwieweit die Core Competencies bereits durch die Lehrstoffinhalte der Pflichtschulen in Österreich abgedeckt sind. Das Projekt Financial Core Competencies in Austria (FinCCA) knüpft mittels zweistufiger Gap-Analyse an dieser Fragestellung an: In einem ersten Schritt ist das Projekt darauf ausgerichtet zu untersuchen, inwieweit die Core Competencies durch die Lehrplaninhalte abgedeckt sind. Auf Basis der inhaltsanalytischen Auswertung der Lehrpläne werden in einem weiteren Schritt ausgewählte, in Österreich approbierte, Schulbücher analysiert. Auf Grundlage der zweistufigen Gap-Analyse sollen zentrale Unterrichtsinhalte identifiziert werden, für die abschließend Lehrkonzepte zur Lehrer/innen/bildung im Bereich Finanzbildung entwickelt werden. Insgesamt soll damit ein weiterer wissenschaftlicher Grundpfeiler für eine nationale Strategie zur Förderung von Finanzbildung im Sinne der OECD (vgl. OECD 2015a) geschaffen werden. FinCCA wird als gemeinsames Projekt der Wirtschaftsuniversität Wien, der Karl-Franzens-Universität Graz und der Österreichischen Nationalbank (OeNB) durchgeführt. Dieser Artikel gibt unter Berücksichtigung des Forschungstands einen Einblick in die Zielsetzung, das Projektdesign und ausgewählte Projektergebnisse. Die Ergebnisse geben einen Einblick inwiefern bestimmte inhaltliche Themenbereiche grundlegender Finanzbildung bereits innerhalb des Lehrstoffes österreichischer Pflichtschulen berücksichtigt sind. Der Artikel schließt mit Ansatzpunkten zur Verbesserung grundlegender Finanzbildung und gibt einen Ausblick über die weitere Vorgehensweise

    A geological 3D-model of Austria

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    GeoSphere Austria (formerly Geologische Bundesanstalt - Geological Survey of Austria) has produced a supra-regional 3D framework model called “3D AUSTRIA” providing a large-scale geological overview for professional geologists, students and the public. This model is intended to act as support for subsequent regional modelling projects as well as for educational and communicational purpose. The modelled domain of covers a rectangular area of 175 000 km² including the national borders of Austria, down to a depth to 60 km below sea level. Model units are defined following the nomenclature of Schmid et al. (2004) and Froitzheim et al. (2008), each unit having a specific paleo-geographic origin and tectono-metamorphic history. Seven modelling units are considered: two continental plates (1) the Adriatic Plate, (2) the Eurasian Plate, four units from the Alpine orogenic wedge (3) the South-Alpine Superunit, (4) the Austroalpine Superunit, (5) the Penninic Superunit, (6) the Sub-Penninic Superunit and (7) Neogene sedimentary basins in the foreland and within the Alps. Due to the large-scale character of the model, relatively small constituents of the Alpine Orogen are merged together (Meliata Superunit and Inner Western Carpathian Superunit with the Austroalpine Superunit, Helvetic Superunit and Allochtone Molasse with the Sup-Penninic Superunit, intrusive rocks along the Periadriatic Fault with their host unit, minor Neogene basins with the Austroalpine Superunit). The model geometry is constrained by the geological map of Austria 1:1.5M (Schuster et al., 2019), (2) 24 published cross sections and (3) published contour maps for the Moho discontinuity (Ziegler & Dèzes, 2006) and the large Neogene basins. It has been generated with the SKUA-GOCAD software suite following the workflow of Pfleiderer et al. (2016). The framework model 3D AUSTRIA can be visualized with the web 3D Viewer of Geosphere Austria (https://gis.geosphere.at/portal/home/webscene/viewer.html?webscene=c11cd25795294ba8b6f276ab2d072afb) or downloaded from the Tethys Research Data Repository (https://doi.tethys.at/10.24341/tethys.184) allowing the generation of a physical multi-part model using 3D printing technology. It provides a unique way to comprehend the fundamentally 3D nature of sedimentary and tectonic features, like the unconformity at the base of Neogene sedimentary basins, the Alpine frontal thrust or the Tauern Window. The data acquired in the framework of the AlpArray project can be used in future for refining the geometry of 3D AUSTRIA

    Besser Lesen am Bildschirm? : Nutzerbeobachtung mittels Eyetracking und Interviews geben Einblicke in das Online-Lesen

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    Ziel der transdisziplinären Vorstudie war es, herauszufinden, ob ein Softwareprodukt mithilfe von spezieller Textauszeichnung die Informationsverarbeitung beim Online-Lesen verändern kann. Mittels Nutzerbeobachtung wurden quantitative Daten zur Lesegeschwindigkeit und Behaltensleistung und qualitative Daten zum Leseverhalten erhoben. Die Ergebnisse zeigten eine niedrige Lesegeschwindigkeit und keine signifikanten Unterschiede zwischen ausgezeichneten und normalen Texten. Gleichzeitig zeigte sich bei der Behaltensleistung eine messbare Differenz und die Eyetracking-Daten lieferten einen Hinweis für eine veränderte Informationsaufnahme. Die Interviews gaben einen Einblick in das individuelle Leseverhalten. Kurzum, die Vorstudie konnte erste Anhaltspunkte aufzeigen, dass das Softwareprodukt die Informationsverarbeitung verändern kann. Weiterhin lieferte sie wertvolle Erkenntnisse für das Testdesign künftiger Studien, die auch für PraktikerInnen in der Produktentwicklung interessant sind

    Spectroscopic properties of cool Ursa Major group members

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    Until now, most members of the Ursa Major (UMa) group of stars have been identified by means of kinematic criteria. However, in many cases kinematic criteria alone are insufficient to ascertain, whether an individual star is really a member of this group. Since photometric criteria are ineffective in the case of cool dwarf members, one must use spectroscopic criteria. Nevertheless, resulting membership criteria are inconclusive. We reanalyse spectroscopic properties of cool UMa group dwarfs. In particular, we study the distribution of iron abundance, the strength of the Li I absorption at 6708 A and the Li abundance, and the infilling of the core of the H alpha line. Twenty-five cool and northern bona-fide members are carefully selected from the literature. Homogeneously measured stellar parameters and iron abundances are given for all Sun-like stars selected, based on spectra of high resolution and high signal-to-noise ratio. In addition, we measure the Li equivalent width and abundance as well as the relative intensity of the H alpha core and the corresponding chromospheric flux. The studied stars infer an average Ursa Major group iron abundance of -0.03+-0.05 dex, which is higher by about 0.06 dex than determined elsewhere. The Li abundance derived of Ursa Major group dwarf stars is higher than in the Hyades at effective temperatures cooler than the Sun, but lower than in the younger Pleiades, a result which is independent of the exact value of the effective temperature adopted. The Sun-like and cooler dwarfs also display chromospheric infilling of the H alpha core. We present spectroscopic criteria that may be used to exclude non-members.Comment: accepted for publication in A&A, 19 pages, 10 figures, 7 table

    Different activation energies in glucose uptake in Saccharomyces cerevisiae DFY1 suggest two transport systems

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    AbstractThe analysis of initial glucose uptake in Saccharomyces cerevisiae at 25°, 20°, 15° and 10°C by computer-assisted nonlinear regression analysis predicts two transport systems. The first demonstrates Michaelis–Menten kinetics and the second shows first order behaviour. The activation energies of these two systems were calculated by the Arrhenius equation at four different growth phases, namely early exponential (EE), middle exponential (ME2), late exponential (LE) and early stationary (ES) with 2% glucose in the batch medium. The activation energies calculated from the Vm values in EE, ME, LE and ES growth phases were 15.8±1.7, 13.5±1.0, 15.1±0.8 and 13.5±0.7 kcal/mol. These values are in agreement with activation energies calculated for the first mechanism, facilitated diffusion, which is the mechanism deduced from countertransport experiments. The activation energies derived for the second transport system from the first order rate constants in cells grown to EE, ME2, LE and ES were 8.0±2.1, 8.1±1.3, 9.6±3.0 and 7.5±2.6 kcal/mol. These values are still significantly higher than for free diffusion of glucose in water and lower as predicted for passage of glucose through the lipid phase. Therefore, we assume in addition to carrier-mediated facilitated diffusion the entrance of glucose into the cell through a pore

    Gas phase thermometry of hot turbulent jets using laser induced phosphorescence

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    This article is made available through the Brunel Open Access Publishing Fund. Copyright @ 2013 OSAThe temperature distributions of heated turbulent jets of air were determined using two dimensional (planar) laser induced phosphorescence. The jets were heated to specific temperature increments, ranging from 300 – 850 K and several Reynolds numbers were investigated at each temperature. The spectral ratio technique was used in conjunction with thermographic phosphors BAM and YAG:Dy, individually. Single shot and time averaged results are presented as two dimensional stacked images of turbulent jets. YAG:Dy did not produce a high enough signal for single shot measurements. The results allowed for a direct comparison between BAM and YAG:Dy, revealing that BAM is more suitable for relatively lower temperature, fast and turbulent regimes and that YAG:Dy is more suited to relatively higher temperature, steady flow situations

    Recent advances in applying mass spectrometry and systems biology to determine brain dynamics

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    Neurological disorders encompass various pathologies which disrupt normal brain physiology and function. Poor understanding of their underlying molecular mechanisms and their societal burden argues for the necessity of novel prevention strategies, early diagnostic techniques and alternative treatment options to reduce the scale of their expected increase. Areas covered: This review scrutinizes mass spectrometry based approaches used to investigate brain dynamics in various conditions, including neurodegenerative and neuropsychiatric disorders. Different proteomics workflows for isolation/enrichment of specific cell populations or brain regions, sample processing; mass spectrometry technologies, for differential proteome quantitation, analysis of post-translational modifications and imaging approaches in the brain are critically deliberated. Future directions, including analysis of cellular sub-compartments, targeted MS platforms (selected/parallel reaction monitoring) and use of mass cytometry are also discussed. Expert commentary: Here, we summarize and evaluate current mass spectrometry based approaches for determining brain dynamics in health and diseases states, with a focus on neurological disorders. Furthermore, we provide insight on current trends and new MS technologies with potential to improve this analysis.Peer reviewe

    NLTE effects on Fe I/II in the atmospheres of FGK stars and application to abundance analysis of their spectra

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    We describe the first results from our project aimed at large-scale calculations of NLTE abundance corrections for important astrophysical atoms and ions. In this paper, the focus is on Fe which is a proxy of stellar metallicity and is commonly used to derive effective temperature and gravity. We present a small grid of NLTE abundance corrections for Fe I lines and discuss how NLTE effects influence determination of effective temperature, surface gravity, and metallicity for late-type stars.Comment: 6 pages, to be published in IOP The Journal of Physics: Conference Series, proceedings of the Workshop: 'Stellar Atmospheres in the Gaia Era: Quantitative Spectroscopy and Comparative Spectrum Modelling', Brussels, June 201
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