Electron transport and energy relaxation in dilute magnetic alloys

We consider the effect of the RKKY interaction between magnetic impurities on the electron relaxation rates in a normal metal. The interplay between the RKKY interaction and the Kondo effect may result in a non-monotonic temperature dependence of the electron momentum relaxation rate, which determines the Drude conductivity. The electron phase relaxation rate, which determines the magnitude of the weak localization correction to the resistivity, is also a non-monotonic function of temperature. For this function, we find the dependence of the position of its maximum on the concentration of magnetic impurities. We also relate the electron energy relaxation rate to the excitation spectrum of the system of magnetic impurities. The energy relaxation determines the distribution function for the out-of-equilibrium electrons. Measurement of the electron distribution function thus may provide information about the excitations in the spin glass phase.Comment: 15 pages, 5 figure

Validation of the Spanish version of the five-item General Self-Efficacy (GSE) scale in a sample of nursing students: Evidence of validity, reliability, longitudinal invariance and changes in general self-efficacy and resilience in a two-wave cross-lagged panel model.

The aim of this study is to validate the Spanish version of the five-item General Self-Efficacy scale in a sample of nursing students, by: 1) offering evidence of validity and reliability; 2) studying the longitudinal measurement invariance of the scale; 3) providing evidence on the changes in the levels of self-efficacy that occur after one year of nursing education; and 4) offering longitudinal evidence on the relationship between nursing students' self-efficacy and resilience levels. Nurses' general self-efficacy has been related to both personal and organizational outcomes. In Spain, some competencies the students must acquire during the Degree in Nursing implicitly refer to self-efficacy. For the measurement of general self-efficacy, the General Self-Efficacy Scale is one of the most widely used in Europe. A longitudinal design was used. Research took place at the University of Valencia and the University of the Balearic Islands (Spain). Participants were 324 nursing students, in the first year of the Nursing Degree. The five-item General Self-Efficacy scale and the Brief Resilience Coping Scale were used. Analyses included descriptive statistics, reliability estimates, confirmatory factor analysis, a longitudinal measurement invariance routine and several competing cross-lagged models. Evidence of reliability shown by the scale was adequate and a one-factor solution for the structure was found. Additionally, the five-item GSE showed evidence of invariance over time. A causal effect of self-efficacy on nursing students' levels of resilience was found. The Spanish version of the five-item General Self-Efficacy scale is a brief instrument that can contribute to the assessment of some of the basic competencies of the Degree in Nursing, which improve during their education and how these changes are related to other skills important for the nursing profession, such as resilience

PCR-based molecular marker for the Bdv2 Thinopyrum intermedium source of barley yellow dwarf virus resistance in wheat

Because of the importance of BYDV in wheat production worldwide, and given the difficulties of bioassaying for resistance, a molecular marker was developed for the resistance known as Bdv2 that originates on the long arm of chromosome 7Ai1 of Thinopyrum intermedium. This resistance was identified in a partial amphiploid line TAF46, a disomic addition line to wheat (L1), a telosomic addition line (7Ai1 L), and a series of recombinants and translocations. A RAPD (random amplified polymeric DNA) marker for the resistant germplasm was cloned and sequenced, and primers were designed against that sequence to produce a sequence characterised amplified region (SCAR) marker. A single PCR product is produced only with genotypes carrying the resistance from any of the available recombinants. The cloned sequence, recommended primers, and PCR protocols are described. The usefulness of the marker has been demonstrated for following Bdv2 in segregating wheat breeding germplasm, with the imminent release of a BYDV-resistant cultivar

Five-Year Follow Up of a Low Glycaemic Index Dietary Randomised Controlled Trial in Pregnancy—No Long-Term Maternal Effects of a Dietary Intervention

Objective: To determine whether a dietary intervention in pregnancy had a lasting effect on maternal outcomes of diet, HbA1c and weight retention 5 years post-intervention; and to establish whether modifiable maternal behaviours were associated with these outcomes. Design: Randomised control trial of low glycaemic index (GI) diet in pregnancy with longitudinal follow up to 5 years post-intervention. Setting: Dublin, Ireland (2007–2016). Population: In all, 403 women of 759 (53.1%) were followed up at 5 years. A total of 370 (intervention n = 188; control n = 182) were included in this analysis. Methods: Fasting glucose was measured at 13 and 28 weeks’ gestation and HbA1c (mmol/mol) at 5-year follow up. Weight retention (kg) from early pregnancy to 5 years post-intervention was calculated. Dietary intakes, anthropometry, and lifestyle factors were measured in pregnancy and 5 years post-intervention. Multiple linear regression models, controlling for confounders, were used for analysis. Outcome: Maternal diet, HbA1c, and weight retention at 5 years post-intervention. Results: There was no difference between the intervention and control at 5 years post-intervention for any long-term maternal outcomes measured. HbA1c at 5 years post-intervention was associated with early-pregnancy fasting glucose (B 1.70, 95% CI 0.36–3.04) and parity ≥3 (B 1.04, 95% CI 0.09–1.99). Weight retention was associated with change in well-being from pregnancy to 5 years (B −0.06, 95% CI −0.11 to −0.02), gestational weight gain (B 0.19, 95% CI 0.00–0.38), and GI (B 0.26, 95% CI 0.06–0.46) at 5 years. Conclusions: The ROLO low-GI dietary intervention in pregnancy had no impact on maternal dietary intakes, HbA1c or body composition 5 years post-intervention. Maternal factors and lifestyle behaviours in pregnancy have long-term effects on glucose metabolism and weight retention up to 5 years later. Tweetable abstract: Pregnancy factors are associated with maternal glucose metabolism and weight retention 5 years later

Crossover from 2-dimensional to 1-dimensional collective pinning in NbSe3

We have fabricated NbSe$_3$ structures with widths comparable to the Fukuyama-Lee-Rice phase-coherence length. For samples already in the 2-dimensional pinning limit, we observe a crossover from 2-dimensional to 1-dimensional collective pinning when the crystal width is less than 1.6 $\mu$m, corresponding to the phase-coherence length in this direction. Our results show that surface pinning is negligible in our samples, and provide a means to probe the dynamics of single domains giving access to a new regime in charge-density wave physics.Comment: 4 pages, 2 figures, and 1 table. Accepted for publication in Physical Review

Electromagnetic field correlations near a surface with a nonlocal optical response

The coherence length of the thermal electromagnetic field near a planar surface has a minimum value related to the nonlocal dielectric response of the material. We perform two model calculations of the electric energy density and the field's degree of spatial coherence. Above a polar crystal, the lattice constant gives the minimum coherence length. It also gives the upper limit to the near field energy density, cutting off its $1/z^3$ divergence. Near an electron plasma described by the semiclassical Lindhard dielectric function, the corresponding length scale is fixed by plasma screening to the Thomas-Fermi length. The electron mean free path, however, sets a larger scale where significant deviations from the local description are visible.Comment: 15 pages, 7 figure files (.eps), \documentclass[global]{svjour}, accepted in special issue "Optics on the Nanoscale" (Applied Physics B, eds. V. Shalaev and F. Tr\"ager

Simulations of amphiphilic fluids using mesoscale lattice-Boltzmann and lattice-gas methods

We compare two recently developed mesoscale models of binary immiscible and ternary amphiphilic fluids. We describe and compare the algorithms in detail and discuss their stability properties. The simulation results for the cases of self-assembly of ternary droplet phases and binary water-amphiphile sponge phases are compared and discussed. Both models require parallel implementation and deployment on large scale parallel computing resources in order to achieve reasonable simulation times for three-dimensional models. The parallelisation strategies and performance on two distinct parallel architectures are compared and discussed. Large scale three dimensional simulations of multiphase fluids requires the extensive use of high performance visualisation techniques in order to enable the large quantities of complex data to be interpreted. We report on our experiences with two commercial visualisation products: AVS and VTK. We also discuss the application and use of novel computational steering techniques for the more efficient utilisation of high performance computing resources. We close the paper with some suggestions for the future development of both models.Comment: 30 pages, 9 figure

The Dependence of the Superconducting Transition Temperature of Organic Molecular Crystals on Intrinsically Non-Magnetic Disorder: a Signature of either Unconventional Superconductivity or Novel Local Magnetic Moment Formation

We give a theoretical analysis of published experimental studies of the effects of impurities and disorder on the superconducting transition temperature, T_c, of the organic molecular crystals kappa-ET_2X and beta-ET_2X (where ET is bis(ethylenedithio)tetrathiafulvalene and X is an anion eg I_3). The Abrikosov-Gorkov (AG) formula describes the suppression of T_c both by magnetic impurities in singlet superconductors, including s-wave superconductors and by non-magnetic impurities in a non-s-wave superconductor. We show that various sources of disorder lead to the suppression of T_c as described by the AG formula. This is confirmed by the excellent fit to the data, the fact that these materials are in the clean limit and the excellent agreement between the value of the interlayer hopping integral, t_perp, calculated from this fit and the value of t_perp found from angular-dependant magnetoresistance and quantum oscillation experiments. If the disorder is, as seems most likely, non-magnetic then the pairing state cannot be s-wave. We show that the cooling rate dependence of the magnetisation is inconsistent with paramagnetic impurities. Triplet pairing is ruled out by several experiments. If the disorder is non-magnetic then this implies that l>=2, in which case Occam's razor suggests that d-wave pairing is realised. Given the proximity of these materials to an antiferromagnetic Mott transition, it is possible that the disorder leads to the formation of local magnetic moments via some novel mechanism. Thus we conclude that either kappa-ET_2X and beta-ET_2X are d-wave superconductors or else they display a novel mechanism for the formation of localised moments. We suggest systematic experiments to differentiate between these scenarios.Comment: 18 pages, 5 figure