148 research outputs found

    Solutions of the Faddeev-Yakubovsky equations for the four nucleons scattering states

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    The Faddeev-Yakubowsky equations in configuration space have been solved for the four nucleon system. The results with an S-wave interaction model in the isospin approximation are presented. They concern the bound and scattering states below the first three-body threshold. The elastic phase-shifts for the N+NNN reaction in different (S,TS,T) channels are given and the corresponding low energy expansions are discussed. Particular attention is payed to the n+t elastic cross section. Its resonant structure is well described in terms of a simple NN interaction. First results concerning the S-matrix for the coupled N+NNN-NN+NN channels and the strong deuteron-deuteron scattering length are obtained.Comment: latex.tar.gz, 36 pages, 10 figures, 11 tables. To be published in Physical Review

    Nuclear shadowing in polarized DIS on ^6LiD at small x and its effect on the extraction of the deuteron spin structure function g_{1}^{d}(x,Q^2)

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    We consider the effect of nuclear shadowing in polarized deep inelastic scattering (DIS) on ^6LiD at small Bjorken x and its relevance to the extraction of the deuteron spin structure function g_{1}^{d}(x,Q^2). Using models, which describe nuclear shadowing in unpolarized DIS, we demonstrate that the nuclear shadowing correction to g_{1}^{d}(x,Q^2) is significant.Comment: 17 pages, 2 figure

    Measurement properties of quality of life measurement instruments for infants, children and adolescents with eczema: protocol for a systematic review

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    Background: Eczema is a common chronic or chronically relapsing skin disease that has a substantial impact on quality of life (QoL). By means of a consensus-based process, the Harmonising Outcome Measures in Eczema (HOME) initiative has identified QoL as one of the four core outcome domains to be assessed in all eczema trials. Few measurement instruments exist to measure QoL in infants and children with eczema, but there is a great variability in both content and quality (for example, reliability and validity) of the instruments used, and it is not always clear if the best instrument is being used. Therefore, the aim of the proposed research is a comprehensive systematic assessment of the measurement properties of the existing measurement instruments that were developed and/or validated for the measurement of patient-reported QoL in infants and children with eczema. Methods/Design: This study is a systematic review of the measurement properties of patient-reported measures of QoL developed and/or validated for infants and children with eczema. Medline via PubMed and EMBASE will be searched using a selection of relevant search terms. Eligible studies will be primary empirical studies evaluating, describing, or comparing measurement properties of QoL instruments for infants and children with eczema. Eligibility assessment and data abstraction will be performed independently by two reviewers. Evidence tables will be generated for study characteristics, instrument characteristics, measurement properties, and interpretability. The adequacy of the measurement properties will be assessed using predefined criteria. Methodological quality of studies will be assessed using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. A best evidence synthesis will be undertaken if more than one study has investigated a particular measurement property. Discussion: The proposed systematic review will produce a comprehensive assessment of measurement properties of existing QoL instruments in infants and children with eczema. We aim to identify one best currently available instrument to measure QoL in infants and/or children with eczema

    Spin and Orbital Spectroscopy in the Absence of Coulomb Blockade in Lead Telluride Nanowire Quantum Dots

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    We investigate quantum dots in semiconductor PbTe nanowire devices. Due to the accessibility of ambipolar transport in PbTe, quantum dots can be occupied both with electrons and holes. Owing to a very large dielectric constant in PbTe of order 1000, we do not observe Coulomb blockade which typically obfuscates the orbital and spin spectra. We extract large and highly anisotropic effective Lande g-factors, in the range 20-44. The absence of Coulomb blockade allows direct readout, at zero source-drain bias, of spin-orbit hybridization energies of up to 600 microelectronvolt. These spin properties make PbTe nanowires, the recently synthesized members of group IV-VI materials family, attractive as a materials platform for quantum technology, such as spin and topological qubits.Comment: Full transport data available via Zenodo at https://zenodo.org/communities/frolovlab

    Quantum Monte Carlo Calculations of A6A\leq6 Nuclei

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    The energies of 3H^{3}H, 3He^{3}He, and 4He^{4}He ground states, the 32{\frac{3}{2}}^{-} and 12{\frac{1}{2}}^{-} scattering states of 5He^{5}He, the ground states of 6He^{6}He, 6Li^{6}Li, and 6Be^{6}Be and the 3+3^{+} and 0+0^{+} excited states of 6Li^{6}Li have been accurately calculated with the Green's function Monte Carlo method using realistic models of two- and three-nucleon interactions. The splitting of the A=3A=3 isospin T=12T=\frac{1}{2} and A=6A=6 isospin T=1T=1, Jπ=0+J^{\pi} = 0^{+} multiplets is also studied. The observed energies and radii are generally well reproduced, however, some definite differences between theory and experiment can be identified.Comment: 12 pages, 1 figur

    Measurement properties of adult quality-of-life measurement instruments for eczema: protocol for a systematic review

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    Background Eczema is a common chronic or chronically relapsing skin disease that has a substantial impact on quality of life (QoL). By means of a consensus-based process, the Harmonising Outcome Measures in Eczema (HOME) initiative has identified QoL as one of the four core outcome domains to be assessed in all eczema trials (Allergy 67(9):1111-7, 2012). Various measurement instruments exist to measure QoL in adults with eczema, but there is a great variability in both content and quality (for example, reliability and validity) of the instruments used, and it is not always clear if the best instrument is being used. Therefore, the aim of the proposed research is a comprehensive systematic assessment of the measurement properties of the existing measurement instruments that were developed and/or validated for the measurement of patient-reported QoL in adults with eczema. Methods/Design This study is a systematic review of the measurement properties of patient-reported measures of QoL developed and/or validated for adults with eczema. Medline via PubMed and EMBASE will be searched using a selection of relevant search terms. Eligible studies will be primary empirical studies evaluating, describing, or comparing measurement properties of QoL instruments for adult patients with eczema. Eligibility assessment and data abstraction will be performed independently by two reviewers. Evidence tables will be generated for study characteristics, instrument characteristics, measurement properties, and interpretability. The quality of the measurement properties will be assessed using predefined criteria. Methodological quality of studies will be assessed using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. A best evidence synthesis will be undertaken if more than one study has investigated a particular measurement property. Discussion The proposed systematic review will produce a comprehensive assessment of measurement properties of existing QoL instruments in adult patients with eczema. We aim to identify one best currently available instrument to measure QoL in eczema patients

    Single-crystalline PbTe film growth through reorientation

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    Heteroepitaxy enables the engineering of novel properties, which do not exist in a single material. Two principle growth modes are identified for material combinations with large lattice mismatch, Volmer-Weber and Stranski-Krastanov. Both lead to the formation of three-dimensional islands, hampering the growth of flat defect-free thin films. This limits the number of viable material combinations. Here, we report a distinct growth mode found in molecular beam epitaxy of PbTe on InP initiated by pre-growth surface treatments. Early nucleation forms islands analogous to the Volmer-Weber growth mode, but film closure exhibits a flat surface with atomic terracing. Remarkably, despite multiple distinct crystal orientations found in the initial islands, the final film is single-crystalline. This is possible due to a reorientation process occurring during island coalescence, facilitating high quality heteroepitaxy despite the large lattice mismatch, difference in crystal structures and diverging thermal expansion coefficients of PbTe and InP. This growth mode offers a new strategy for the heteroepitaxy of dissimilar materials and expands the realm of possible material combinations

    Evaluation of measurement properties of self-administered PROMs aimed at patients with non-specific shoulder pain and “activity limitations”: a systematic review

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    OBJECTIVE: To critically appraise and compare the measurement properties of self-administered patient-reported outcome measures (PROMs) focussing on the shoulder, assessing "activity limitations." STUDY DESIGN: Systematic review. The study population had to consist of patients with shoulder pain. We excluded postoperative patients or patients with generic diseases. The methodological quality of the selected studies and the results of the measurement properties were critically appraised and rated using the COSMIN checklist. RESULTS: Out of a total of 3427 unique hits, 31 articles, evaluating 7 different questionnaires, were included. The SPADI is the most frequently evaluated PROM and its measurement properties seem adequate apart from a lack of information regarding its measurement error and content validity. CONCLUSION: For English, Norwegian and Turkish users, we recommend to use the SPADI. Dutch users could use either the SDQ or the SST. In German, we recommend the DASH. In Tamil, Slovene, Spanish and the Danish languages, the evaluated PROMs were not yet of acceptable validity. None of these PROMs showed strong positive evidence for all measurement properties. We propose to develop a new shoulder PROM focused on activity limitations, taking new knowledge and techniques into account

    Stereoscopic Visualization of Diffusion Tensor Imaging Data: A Comparative Survey of Visualization Techniques

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    Diffusion tensor imaging (DTI) data has traditionally been displayed as a grayscale functional anisotropy map (GSFM) or color coded orientation map (CCOM). These methods use black and white or color with intensity values to map the complex multidimensional DTI data to a two-dimensional image. Alternative visualization techniques, such as V (max) maps utilize enhanced graphical representation of the principal eigenvector by means of a headless arrow on regular nonstereoscopic (VM) or stereoscopic display (VMS). A survey of clinical utility of patients with intracranial neoplasms was carried out by 8 neuroradiologists using traditional and nontraditional methods of DTI display. Pairwise comparison studies of 5 intracranial neoplasms were performed with a structured questionnaire comparing GSFM, CCOM, VM, and VMS. Six of 8 neuroradiologists favored V (max) maps over traditional methods of display (GSFM and CCOM). When comparing the stereoscopic (VMS) and the non-stereoscopic (VM) modes, 4 favored VMS, 2 favored VM, and 2 had no preference. In conclusion, processing and visualizing DTI data stereoscopically is technically feasible. An initial survey of users indicated that V (max) based display methodology with or without stereoscopic visualization seems to be preferred over traditional methods to display DTI data
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