1,891 research outputs found

    Чому не побачила світ рецензія Євгена Гуцала на книжку Григора Тютюнника?

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    Dit artikel doet verslag van een beschrijvend onderzoek naar de burgerschapsdoelen die leraren in de beroepsgerichte vakken in de bovenbouw van het vmbo in hun lessen nastreven en de wijze waarop ze aan die doelen werken. Vijftien vakleraren, werkzaam in diverse sectoren werden geïnterviewd. De leraren zeggen weinig bezig te zijn met burgerschap als thema en doel. Tegelijkertijd besteden ze wel aandacht aan maatschappelijk verantwoord handelen en aan zelfkennis, vaardigheden en houdingen die te maken hebben met de relatie van de leerling tot anderen en de samenleving. In de context van het leren in levensechte beroepscontexten werken ze onder meer aan samenwerken, een goede werk- en beroepshouding en, met name in het geval van het technisch onderwijs, gezamenlijke zorg voor en reflectie op de kwaliteit van het werk. In de discussie gaan we in op de mogelijkheden voor een, in vergelijking tot algemene vormen van onderwijs, relatief eigen karakter van burgerschapsvorming in het vmbo en leggen een relatie met Sennetts visie op vakmanschap als burgerschap

    Laboratory observations of slow earthquakes and the spectrum of tectonic fault slip modes

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    Slow earthquakes represent an important conundrum in earthquake physics. While regular earthquakes are catastrophic events with rupture velocities governed by elastic wave speed, the processes that underlie slow fault slip phenomena, including recent discoveries of tremor, slow-slip and low-frequency earthquakes, are less understood. Theoretical models and sparse laboratory observations have provided insights, but the physics of slow fault rupture remain enigmatic. Here we report on laboratory observations that illuminate the mechanics of slow-slip phenomena. We show that a spectrum of slow-slip behaviours arises near the threshold between stable and unstable failure, and is governed by frictional dynamics via the interplay of fault frictional properties, effective normal stress and the elastic stiffness of the surrounding material. This generalizable frictional mechanism may act in concert with other hypothesized processes that damp dynamic ruptures, and is consistent with the broad range of geologic environments where slow earthquakes are observed

    Attrition-enhanced total resolution leads to homochiral families of amino acid derivatives

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    The total resolution of five structurally similar racemizable amino acid derivatives, three of which have racemic crystal structures, was performed simultaneously. By enantioselective incorporation in an amino acid derivative that forms a conglomerate the other four were deracemized on attrition-induced grinding. The outcome of the resolution was random (R) or (S), but all compounds had the same absolute configuration and high enantiomeric purities.

    Dynamic Impedance of Two-Dimensional Superconducting Films Near the Superconducting Transition

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    The sheet impedances, Z(w,T), of several superconducting a-Mo77Ge23 films and one In/InOx film have been measured in zero field using a two-coil mutual inductance technique at frequencies from 100 Hz to 100 kHz. Z(w,T) is found to have three contributions: the inductive superfluid, renormalized by nonvortex phase fluctuations; conventional vortex-antivortex pairs, whose contribution turns on very rapidly just below the usual Kosterlitz-Thouless-Berezinskii unbinding temperature; and an anomalous contribution. The latter is predominantly resistive, persists well below the KTB temperature, and is weakly dependent on frequency down to remarkably low frequencies, at least 100 Hz. It increases with T as e-U'(T)/kT, where the activation energy, U'(T), is about half the energy to create a vortex-antivortex pair, indicating that the frequency dependence is that of individual excitations, rather than critical behavior.Comment: 10 pages, 10 figs; subm PR

    Alien Registration- Leeman, Florence M. (Verona, Hancock County)

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    https://digitalmaine.com/alien_docs/18192/thumbnail.jp

    Citizenship in prevocational education: Professional pride as a source

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    The practice of citizenship education has predominantly been studied in general education. This article details an interview study of citizenship education of teachers in prevocational education in the Netherlands. We investigated whether and how vocational teachers reflected on their goals and teaching practices in citizenship education. Teachers did not perceive their teaching to be working on citizenship. However, they aimed at developing professional attitudes in their students, emphasising participation and ‘doing their work well’ in order to become respected and personally responsible workers/employees. In technical education, the development of pride in and shared responsibility for the quality of the students’ craftwork was emphasised. These findings are discussed in relation to Sennett’s views on the development of craftsmanship as citizenship. We see these views as strategic openings for an alternative to the dominant verbal, individualising and adaptation oriented approach of citizenship education

    Single-vortex-induced voltage steps in Josephson-junction arrays

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    We have numerically and analytically studied ac+dc driven Josephson-junction arrays with a single vortex or with a single vortex-antivortex pair present. We find single-vortex steps in the voltage versus current characteristics (I-V) of the array. They correspond microscopically to a single vortex phase-locked to move a fixed number of plaquettes per period of the ac driving current. In underdamped arrays we find vortex motion period doubling on the steps. We observe subharmonic steps in both underdamped and overdamped arrays. We successfully compare these results with a phenomenological model of vortex motion with a nonlinear viscosity. The I-V of an array with a vortex-antivortex pair displays fractional voltage steps. A possible connection of these results to present day experiments is also discussed.Comment: 10 pages double sided with figures included in the text. To appear in Journal of Physics, Condensed Matte

    Transverse phase-locking in fully frustrated Josephson junction arrays: a new type of fractional giant steps

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    We study, analytically and numerically, phase locking of driven vortex lattices in fully-frustrated Josephson junction arrays at zero temperature. We consider the case when an ac current is applied {\it perpendicular} to a dc current. We observe phase locking, steps in the current-voltage characteristics, with a dependence on external ac-drive amplitude and frequency qualitatively different from the Shapiro steps, observed when the ac and dc currents are applied in parallel. Further, the critical current increases with increasing transverse ac-drive amplitude, while it decreases for longitudinal ac-drive. The critical current and the phase-locked current step width, increase quadratically with (small) amplitudes of the ac-drive. For larger amplitudes of the transverse ac-signal, we find windows where the critical current is hysteretic, and windows where phase locking is suppressed due to dynamical instabilities. We characterize the dynamical states around the phase-locking interference condition in the IVIV curve with voltage noise, Lyapunov exponents and Poincar\'e sections. We find that zero temperature phase-locking behavior in large fully frustrated arrays is well described by an effective four plaquette model.Comment: 12 pages, 11 figure
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