3,210 research outputs found

    Continuing professional development for the early years workforce in England since 2015: a synthesis of survey data highlighting commonalities, discrepancies and gaps

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    Continuing Professional Development (CPD) is an essential aspect of Early Years (EY) workforce planning. In understanding how CPD is currently provided, we depend largely on surveys carried out by separate sector organisations with little synthesis of the data. In this paper, we scrutinise findings relating to CPD from nine surveys of EY managers and practitioners carried out by three well-established sector organisations since 2015. We highlight commonalities, discrepancies and gaps in the data. On the basis of this analysis, we highlight the need for further investigation around what constitutes CPD in the EY sector, what are perceived to be ‘quality’ experiences, CPD accreditation and the leadership and management of CPD in settings. We recommend gathering more detailed and accurate data about CPD through practitioner logs completed as and when CPD is undertaken, as opposed to retrospective surveys

    Analytical study of coherence in seeded modulation instability

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    We derive analytical expressions for the coherence in the onset of modulation instability, in excellent agreement with thorough numerical simulations. As usual, we start by a linear perturbation analysis, where broadband noise is added to a continuous wave (CW) pump; then, we investigate the effect of adding a deterministic seed to the CW pump, a case of singular interest as it is commonly encountered in parametric amplification schemes. Results for the dependence of coherence on parameters such as fiber type, pump power, propagated distance, seed signal-to-noise ratio are presented. Finally, we show the importance of including higher-order linear and nonlinear dispersion when dealing with generation in longer wavelength regions (mid IR). We believe these results to be of relevance when applied to the analysis of the coherence properties of supercontinua generated from CW pumps.Comment: 6 pages, 8 figure

    Non-linear frequency and amplitude modulation of a nano-contact spin torque oscillator

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    We study the current controlled modulation of a nano-contact spin torque oscillator. Three principally different cases of frequency non-linearity (d2f/dIdc2d^{2}f/dI^{2}_{dc} being zero, positive, and negative) are investigated. Standard non-linear frequency modulation theory is able to accurately describe the frequency shifts during modulation. However, the power of the modulated sidebands only agrees with calculations based on a recent theory of combined non-linear frequency and amplitude modulation.Comment: 4 pages, 4 figure

    Frequency modulation of spin torque oscillator pairs

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    The current controlled modulation of nano-contact based spin torque oscillator (STO) pairs is studied in both the synchronized and non-synchronized states. The synchronized state shows a well behaved modulation and demonstrates robust mutual locking even under strong modulation. The power distribution of the modulation sidebands can be quantitatively described by assuming a single oscillator model. However, in the non-synchronized state, the modulation sidebands are not well described by the model, indicating interactions between the two individual nano-contact STOs. These findings are promising for potential applications requiring the modulation of large synchronized STO arrays

    Direct Observation of Large Amplitude Spin Excitations Localized in a Spin-Transfer Nanocontact

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    We report the direct observation of large amplitude spin-excitations localized in a spin-transfer nanocontact using scanning transmission x-ray microscopy. Experiments were conducted using a nanocontact to an ultrathin ferromagnetic multilayer with perpendicular magnetic anisotropy. Element resolved x-ray magnetic circular dichroism images show an abrupt onset of spin excitations at a threshold current that are localized beneath the nanocontact, with average spin precession cone angles of 25{\deg} at the contact center. The results strongly suggest that we have observed a localized magnetic soliton.Comment: 5 pages, 3 figure
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