Comparative Analysis of Non-thermal Emissions and Study of Electron Transport in a Solar Flare

We study the non-thermal emissions in a solar flare occurring on 2003 May 29 by using RHESSI hard X-ray (HXR) and Nobeyama microwave observations. This flare shows several typical behaviors of the HXR and microwave emissions: time delay of microwave peaks relative to HXR peaks, loop-top microwave and footpoint HXR sources, and a harder electron energy distribution inferred from the microwave spectrum than from the HXR spectrum. In addition, we found that the time profile of the spectral index of the higher-energy (\gsim 100 keV) HXRs is similar to that of the microwaves, and is delayed from that of the lower-energy (\lsim 100 keV) HXRs. We interpret these observations in terms of an electron transport model called {\TPP}. We numerically solved the spatially-homogeneous {\FP} equation to determine electron evolution in energy and pitch-angle space. By comparing the behaviors of the HXR and microwave emissions predicted by the model with the observations, we discuss the pitch-angle distribution of the electrons injected into the flare site. We found that the observed spectral variations can qualitatively be explained if the injected electrons have a pitch-angle distribution concentrated perpendicular to the magnetic field lines rather than isotropic distribution.Comment: 32 pages, 12 figures, accepted for publication in The Astronomical Journa

Weiss oscillations in the electronic structure of modulated graphene

We present a theoretical study of the electronic structure of modulated graphene in the presence of a perpendicular magnetic field. The density of states and the bandwidth for the Dirac electrons in this system are determined. The appearance of unusual Weiss oscillations in the bandwidth and density of states is the main focus of this work.Comment: 8 pages, 2 figures, accepted in J. Phys.: Conden. mat

The Rollercoaster Ride : An Interpretative Phenomenological Analysis of Parental Decision- Making Concerning Academic Redshirting of School Entry

The decision concerning when a child should commence formal schooling has become increasingly complex in contemporary society. Worldwide, a growing number of children do not commence formal schooling until six or seven years of age (World Bank, 2021). In Australia, current school starting age policies afford some parents (dependent on the child’s birth month) the flexibility to decide when their child will commence formal schooling. This results in some children starting school at 4.5 years of age (Early Childhood Intervention Australia [ECIA, NSW Chapter], 2017). However, there has been an increasing number of children in Australia commencing school a year after the child is first eligible, a practice commonly referred to as academic redshirting (Edwards et al., 2011). Approximately 15 per cent of children are academically redshirted around Australia each year (Edwards et al., 2011). In New South Wales (NSW), Hanly et al. (2019) revealed 26 per cent of children were academically redshirted, which equated to half of all the children who were eligible to do so, experiencing a delayed school entry. Both statistics are notably higher than international estimates of 4 to 9 per cent of children across the globe being academically redshirted annually (Bassok & Reardon, 2013; Dhuey, 2016). The higher incidence of academic redshirting in Australia, and in particular NSW, warranted the need for this study, to explore how parents make the decision regarding when their child should commence formal schooling. This qualitative study used Interpretative Phenomenological Analysis (IPA). IPA involves exploring the lived experience of a phenomenon, with a particular emphasis on an individual’s sense-making of the experience (Smith et al., 2022). The purpose of this study was to explore the lived experience of parents who were making the important decision concerning academic redshirting and school entry. Data was collected individually through semi-structured interviews with 10 parents and collectively, through four focus groups with parents from various regions across NSW. The findings of the study revealed parents experienced varying levels of stress regarding decision-making, with those making the decision for the first time experiencing higher levels of anxiety. Themes were generated from the data analysis and are based on the key concepts that were identified at the stage of data analysis: cycles of indecision, ambiguity, and experiences of misalignment. This study makes an important contribution to the existing body of knowledge. This qualitative study has explored parents’ perspectives on the decision-making in NSW, Australia, where academic redshirting rates are more than double the national average (Edwards et al., 2011). Methodologically, this study offers a different research lens to exploring academic redshirting practices in Australia, given most research conducted has been quantitative (see Edwards et al., 2011; Hanly et al., 2019). As a result of this study, several recommendations are proposed. Two key recommendations for policy makers include the following: firstly, the findings indicate a need to change school starting age policies in Australia. Secondly, a stronger partnership between Early Childhood Education and Care (ECEC) and schools needs to be established to enable a smoother school transition for all

Predicting the outcome of Disability Living Allowance (DLA) adult claims

This working paper considers how well coded data from Disability Living Allowance (DLA) adult claim packs can predict the outcome of these claims. The probability of receiving a care or mobility award is estimated. A range of control variables are considered. First using items that reflect the entitlement criteria for care and mobility awards and then looking at whether additional evidence was required as part of the claim process. Predicted results from these estimates were then compared with real world decisions and those made by Decision Makers on the basis of the coded information from claim packs

Teaching percutaneous renal biopsy using unfixed human cadavers

Background: Percutaneous renal biopsy (PRB) is an important diagnostic procedure. Despite advances in its safety profile there remains a small but significant risk of bleeding complications. Traditionally, operators train to perform PRB through tutor instruction and directly supervised PRB attempts on real patients. We describe an approach to teaching operators to perform PRB using cadaveric simulation. Methods: We devised a full day course hosted in the Clinical Anatomy Skills Centre, with places for nine candidates. Course faculty consisted of two Consultant Nephrologists, two Nephrology trainees experienced in PRB, and one Radiologist. Classroom instruction included discussion of PRB indications, risk minimisation, and management of complications. Two faculty members acted as models for the demonstration of kidney localisation using real-time ultrasound scanning. PRB was demonstrated using a cadaveric model, and candidates then practised PRB using each cadaver model. Results: Written candidate feedback was universally positive. Faculty considered the cadaveric model a realistic representation of live patients, while the use of multiple cadavers introduced anatomical variation. Conclusions: Our model facilitates safe simulation of a high risk procedure. This might reduce serious harm associated with PRB and improve patient safety, benefiting trainee operators and patients alike

Tunneling edges at strong disorder

Scattering between edge states that bound one-dimensional domains of opposite potential or flux is studied, in the presence of strong potential or flux disorder. A mobility edge is found as a function of disorder and energy, and we have characterized the extended phase. "paper_FINAL.tex" 439 lines, 20366 characters In the presence of flux and/or potential disorder, the localization length scales exponentially with the width of the barrier. We discuss implications for the random-flux problem.Comment: RevTeX, 4 page

Fast electron slowing-down and diffusion in a high temperature coronal X-ray source

Finite thermal velocity modifications to electron slowing-down rates may be important for the deduction of solar flare total electron energy. Here we treat both slowing-down and velocity diffusion of electrons in the corona at flare temperatures, for the case of a simple, spatially homogeneous source. Including velocity diffusion yields a consistent treatment of both "accelerated" and "thermal" electrons. It also emphasises that one may not invoke finite thermal velocity target effects on electron lifetimes without simultaneously treating the contribution to the observed X-ray spectrum from thermal electrons. We present model calculations of the X-ray spectra resulting from injection of a power-law energy distribution of electrons into a source with finite temperature. Reducing the power-law distribution low-energy cutoff to lower and lower energies only increases the relative magnitude of the thermal component of the spectrum, because the lowest energy electrons simply join the background thermal distribution. Acceptable fits to RHESSI flare data are obtained using this model. These also demonstrate, however, that observed spectra may in consequence be acceptably consistent with rather a wide range of injected electron parameters