Pairing symmetry signatures of T1 in superconducting ferromagnets

We study the nuclear relaxation rate 1/T1 as a function of temperature for a superconducting-ferromagnetic coexistent system using a p-wave triplet model for the superconducting pairing symmetry. This calculation is contrasted with a singlet s-wave one done previously, and we see for the s-wave case that there is a Hebel-Slichter peak, albeit reduced due to the magnetization, and no peak for the p-wave case. We then compare these results to a nuclear relaxation rate experiment on UGe2 to determine the possible pairing symmetry signatures in that material. It is seen that the experimental data is inconclusive to rule out the possibility of s-wave pairing in $UGe_{2}$.Comment: 4 pages, 4 figure

Physical properties of ferromagnetic-superconducting coexistent system

We studied the nuclear relaxation rate 1/T1 of a ferromagnetic-superconducting system from the mean field model proposed in Ref.14. This model predicts the existence of a set of gapless excitations in the energy spectrum which will affect the properties studied here, such as the density of states and, hence, 1/T1. The study of the temperature variation of 1/T1(for T<Tc) shows that the usual Hebel-Slichter peak exists, but will be reduced because of the dominant role of the gapless fermions and the background magnetic behavior. We have also presented the temperature dependence of ultrasonic attenuation and the frequency dependence of electromagnetic absorption within this model. We are successful in explaining certain experimental results.Comment: 10 Pages, 9 figute

Validated helioseismic inversions for 3-D vector flows

According to time-distance helioseismology, information about internal fluid motions is encoded in the travel times of solar waves. The inverse problem consists of inferring 3-D vector flows from a set of travel-time measurements. Here we investigate the potential of time-distance helioseismology to infer 3-D convective velocities in the near-surface layers of the Sun. We developed a new Subtractive Optimally Localised Averaging (SOLA) code suitable for pipeline pseudo-automatic processing. Compared to its predecessor, the code was improved by accounting for additional constraints in order to get the right answer within a given noise level. The main aim of this study is to validate results obtained by our inversion code. We simulate travel-time maps using a snapshot from a numerical simulation of solar convective flows, realistic Born travel-time sensitivity kernels, and a realistic model of travel-time noise. These synthetic travel times are inverted for flows and the results compared with the known input flow field. Additional constraints are implemented in the inversion: cross-talk minimization between flow components and spatial localization of inversion coefficients. Using modes f, p1 through p4, we show that horizontal convective flow velocities can be inferred without bias, at a signal-to-noise ratio greater than one in the top 3.5 Mm, provided that observations span at least four days. The vertical component of velocity (v_z), if it were to be weak, is more difficult to infer and is seriously affected by cross-talk from horizontal velocity components. We emphasise that this cross-talk must be explicitly minimised in order to retrieve v_z in the top 1 Mm. We also show that statistical averaging over many different areas of the Sun allows for reliably measuring of average properties of all three flow components in the top 5.5 Mm of the convection zone.Comment: 14 pages main paper, 9 pages electronic supplement, 28 figures. Accepted for publication in Astronomy & Astrophysic

Space-time segmentation method for study of the vertical structure and evolution of solar supergranulation from data provided by local helioseismology

Solar supergranulation remains a mystery in spite of decades of intensive studies. Most of the papers about supergranulation deal with its surface properties. Local helioseismology provides an opportunity to look below the surface and see the vertical structure of this convective structure. We present a concept of a (3+1)-D segmentation algorithm capable of recognising individual supergranules in a sequence of helioseismic 3-D flow maps. As an example, we applied this method to the state-of-the-art data and derived descriptive statistical properties of segmented supergranules -- typical size of 20--30 Mm, characteristic lifetime of 18.7 hours, and estimated depth of 15--20 Mm. We present preliminary results obtained on the topic of the three-dimensional structure and evolution of supergranulation. The method has a great potential in analysing the better data expected from the helioseismic inversions, which are being developed.Comment: 6 pages, 4 figures, accepted in New Astronom

Indigenous child care - leading the way

We believe that the Australian early childhood sector is not performing well. The incidence of poor outcomes for children is increasing, and we believe that current service delivery is not capable of addressing this. We argue that, as a sector, there is an abundance of evidence of the kinds of programs and initiatives that could address our national concerns, and review some of that evidence. We also point out that there is considerable knowledge in Australia, based on Australian programmes and experience, that can be used to build a different early childhood sector with the potential to significantly impact on growing disadvantage. We conclude with the principles or themes around which such initiatives should be developed and a call to advocate for the development of such services. Appropriate services supporting all of our young children, their families and their communities, have the potential to make a huge impact on our society, and we can no longer hide from our responsibilities and avoid providing such services