1,976 research outputs found

    Designing and Piloting a Tool for the Measurement of the Use of Pronunciation Learning Strategies

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    What appears to be indispensable to drive the field forward and ensure that research findings will be comparable across studies and provide a sound basis for feasible pedagogic proposals is to draw up a classification of PLS and design on that basis a valid and reliable data collection tool which could be employed to measure the use of these strategies in different groups of learners, correlate it with individual and contextual variables, and appraise the effects of training programs. In accordance with this rationale, the present paper represents an attempt to propose a tentative categorization of pronunciation learning strategies, adopting as a point of reference the existing taxonomies of strategic devices (i.e. O'Malley and Chamot 1990; Oxford 1990) and the instructional options teachers have at their disposal when dealing with elements of this language subsystem (e.g. Kelly 2000; Goodwin 2001). It also introduces a research instrument designed on the basis of the classification that shares a number of characteristics with Oxford's (1990) Strategy Inventory for Language Learning but, in contrast to it, includes both Likert-scale and open-ended items. The findings of a pilot study which involved 80 English Department students demonstrate that although the tool requires considerable refinement, it provides a useful point of departure for future research into PLS

    Scoping studies: towards a methodological framework

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    This paper focuses on scoping studies, an approach to reviewing the literature which to date has received little attention in the research methods literature. We distinguish between different types of scoping studies and indicate where these stand in relation to full systematic reviews. We outline a framework for conducting a scoping study based on our recent experiences of reviewing the literature on services for carers for people with mental health problems. Where appropriate, our approach to scoping the field is contrasted with the procedures followed in systematic reviews. We emphasize how including a consultation exercise in this sort of study may enhance the results, making them more useful to policy makers, practitioners and service users. Finally, we consider the advantages and limitations of the approach and suggest that a wider debate is called for about the role of the scoping study in relation to other types of literature reviews

    Loss and decoherence due to stray infrared light in superconducting quantum circuits

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    We find that stray infrared light from the 4 K stage in a cryostat can cause significant loss in superconducting resonators and qubits. For devices shielded in only a metal box, we measured resonators with quality factors Q = 10^5 and qubits with energy relaxation times T_1=120 ns, consistent with a stray light-induced quasiparticle density of 170-230 \mu m^{-3}. By adding a second black shield at the sample temperature, we found about an order of magnitude improvement in performance and no sensitivity to the 4 K radiation. We also tested various shielding methods, implying a lower limit of Q = 10^8 due to stray light in the light-tight configuration.Comment: 4 pages, 4 figure

    Electron affinity of Li: A state-selective measurement

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    We have investigated the threshold of photodetachment of Li^- leading to the formation of the residual Li atom in the 2p2P2p ^2P state. The excited residual atom was selectively photoionized via an intermediate Rydberg state and the resulting Li^+ ion was detected. A collinear laser-ion beam geometry enabled both high resolution and sensitivity to be attained. We have demonstrated the potential of this state selective photodetachment spectroscopic method by improving the accuracy of Li electron affinity measurements an order of magnitude. From a fit to the Wigner law in the threshold region, we obtained a Li electron affinity of 0.618 049(20) eV.Comment: 5 pages,6 figures,22 reference

    24^{24}Mg(pp, α\alpha)21^{21}Na reaction study for spectroscopy of 21^{21}Na

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    The 24^{24}Mg(pp, α\alpha)21^{21}Na reaction was measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory in order to better constrain spins and parities of energy levels in 21^{21}Na for the astrophysically important 17^{17}F(α,p\alpha, p)20^{20}Ne reaction rate calculation. 31 MeV proton beams from the 25-MV tandem accelerator and enriched 24^{24}Mg solid targets were used. Recoiling 4^{4}He particles from the 24^{24}Mg(pp, α\alpha)21^{21}Na reaction were detected by a highly segmented silicon detector array which measured the yields of 4^{4}He particles over a range of angles simultaneously. A new level at 6661 ±\pm 5 keV was observed in the present work. The extracted angular distributions for the first four levels of 21^{21}Na and Distorted Wave Born Approximation (DWBA) calculations were compared to verify and extract angular momentum transfer.Comment: 11 pages, 6 figures, proceedings of the 18th International Conference on Accelerators and Beam Utilization (ICABU2014

    Isobaric multiplet mass equation in the A=31A=31 T=3/2T = 3/2 quartets

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    The observed mass excesses of analog nuclear states with the same mass number AA and isospin TT can be used to test the isobaric multiplet mass equation (IMME), which has, in most cases, been validated to a high degree of precision. A recent measurement [Kankainen et al., Phys. Rev. C 93 041304(R) (2016)] of the ground-state mass of 31^{31}Cl led to a substantial breakdown of the IMME for the lowest A=31,T=3/2A = 31, T = 3/2 quartet. The second-lowest A=31,T=3/2A = 31, T = 3/2 quartet is not complete, due to uncertainties associated with the identity of the 31^{31}S member state. Using a fast 31^{31}Cl beam implanted into a plastic scintillator and a high-purity Ge γ\gamma-ray detection array, γ\gamma rays from the 31^{31}Cl(βγ)(\beta\gamma)31^{31}S sequence were measured. Shell-model calculations using USDB and the recently-developed USDE interactions were performed for comparison. Isospin mixing between the 31^{31}S isobaric analog state (IAS) at 6279.0(6) keV and a nearby state at 6390.2(7) keV was observed. The second T=3/2T = 3/2 state in 31^{31}S was observed at Ex=7050.0(8)E_x = 7050.0(8) keV. Isospin mixing in 31^{31}S does not by itself explain the IMME breakdown in the lowest quartet, but it likely points to similar isospin mixing in the mirror nucleus 31^{31}P, which would result in a perturbation of the 31^{31}P IAS energy. USDB and USDE calculations both predict candidate 31^{31}P states responsible for the mixing in the energy region slightly above Ex=6400E_x = 6400 keV. The second quartet has been completed thanks to the identification of the second 31^{31}S T=3/2T = 3/2 state, and the IMME is validated in this quartet
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