5,190 research outputs found
Aboriginal Rules: The Black History of Australian Football
This paper is interested in the significance of Australian football to the Aboriginal and Torres Strait Islander people of Australia. In particular, this paper is interested in the cultural power of football and how it has foregrounded the struggle and highlighted the contribution that Indigenous people have made to the national football code of Australia. This paper also discusses key moments in Indigenous football history in Australia. It questions further that a greater understanding of this contribution needs to be more fully explored from a national perspective in order to appreciate Indigenous peoples' contribution to the sport not just in elite competitions but also at a community and grass roots level
Geometric scaling in the spectrum of an electron captured by a stationary finite dipole
We examine the energy spectrum of a charged particle in the presence of a
{\it non-rotating} finite electric dipole. For {\emph{any}} value of the dipole
moment above a certain critical value p_{\mathrm{c}}$ an infinite series of
bound states arises of which the energy eigenvalues obey an Efimov-like
geometric scaling law with an accumulation point at zero energy. These
properties are largely destroyed in a realistic situation when rotations are
included. Nevertheless, our analysis of the idealised case is of interest
because it may possibly be realised using quantum dots as artificial atoms.Comment: 5 figures; references added, outlook section reduce
Chaos and localization in the wavefunctions of complex atoms NdI, PmI and SmI
Wavefunctions of complex lanthanide atoms NdI, PmI and SmI, obtained via
multi-configuration Dirac-Fock method, are analyzed for density of states in
terms of partial densities, strength functions (), number of principal
components () and occupancies (\lan n_\alpha \ran^E) of single
particle orbits using embedded Gaussian orthogonal ensemble of one plus
two-body random matrix ensembles [EGOE(1+2)]. It is seen that density of states
are in general multi-modal, 's exhibit variations as function of the
basis states energy and 's show structures arising from localized
states. The sources of these departures from EGOE(1+2) are investigated by
examining the partial densities, correlations between , and
\lan n_\alpha \ran^E and also by studying the structure of the Hamiltonian
matrices. These studies point out the operation of EGOE(1+2) but at the same
time suggest that weak admixing between well separated configurations should be
incorporated into EGOE(1+2) for more quantitative description of chaos and
localization in NdI, PmI and SmI.Comment: There are 9 figure
Multiple scattering of photons by atomic hyperfine multiplets
Mesoscopic interference effects in multiple scattering of photons depend
crucially on the internal structure of the scatterers. In the present article,
we develop the analytical theory of multiple photon scattering by cold atoms
with arbitrary internal hyperfine multiplets. For a specific application, we
calculate the enhancement factor of elastic coherent backscattering as a
function of detuning from an entire hyperfine multiplet of neighboring
resonances that cannot be considered isolated. Our theory permits to understand
why atoms behave differently from classical Rayleigh point-dipole scatterers,
and how the classical description is recovered for larger but still microscopic
objects like molecules or clusters.Comment: minor changes, published versio
Towards precision medicine for pain: diagnostic biomarkers and repurposed drugs
We endeavored to identify objective blood biomarkers for pain, a subjective sensation with a biological basis, using a stepwise discovery, prioritization, validation, and testing in independent cohorts design. We studied psychiatric patients, a high risk group for co-morbid pain disorders and increased perception of pain. For discovery, we used a powerful within-subject longitudinal design. We were successful in identifying blood gene expression biomarkers that were predictive of pain state, and of future emergency department (ED) visits for pain, more so when personalized by gender and diagnosis. MFAP3, which had no prior evidence in the literature for involvement in pain, had the most robust empirical evidence from our discovery and validation steps, and was a strong predictor for pain in the independent cohorts, particularly in females and males with PTSD. Other biomarkers with best overall convergent functional evidence for involvement in pain were GNG7, CNTN1, LY9, CCDC144B, and GBP1. Some of the individual biomarkers identified are targets of existing drugs. Moreover, the biomarker gene expression signatures were used for bioinformatic drug repurposing analyses, yielding leads for possible new drug candidates such as SC-560 (an NSAID), and amoxapine (an antidepressant), as well as natural compounds such as pyridoxine (vitamin B6), cyanocobalamin (vitamin B12), and apigenin (a plant flavonoid). Our work may help mitigate the diagnostic and treatment dilemmas that have contributed to the current opioid epidemic
Analytic Treatment of Positronium Spin Splittings in Light-Front QED
We study the QED bound-state problem in a light-front hamiltonian approach.
Starting with a bare cutoff QED Hamiltonian, , with matrix elements
between free states of drastically different energies removed, we perform a
similarity transformation that removes the matrix elements between free states
with energy differences between the bare cutoff, , and effective
cutoff, \lam (\lam < \Lam). This generates effective interactions in the
renormalized Hamiltonian, . These effective interactions are derived
to order in this work, with . is renormalized
by requiring it to satisfy coupling coherence. A nonrelativistic limit of the
theory is taken, and the resulting Hamiltonian is studied using bound-state
perturbation theory (BSPT). The effective cutoff, \lam^2, is fixed, and the
limit, 0 \longleftarrow m^2 \alpha^2\ll \lam^2 \ll m^2 \alpha \longrightarrow
\infty, is taken. This upper bound on \lam^2 places the effects of
low-energy (energy transfer below \lam) emission in the effective
interactions in the sector. This lower bound on \lam^2
insures that the nonperturbative scale of interest is not removed by the
similarity transformation. As an explicit example of the general formalism
introduced, we show that the Hamiltonian renormalized to reproduces
the exact spectrum of spin splittings, with degeneracies dictated by rotational
symmetry, for the ground state through . The entire calculation is
performed analytically, and gives the well known singlet-triplet ground state
spin splitting of positronium, . We discuss remaining
corrections other than the spin splittings and how they can be treated in
calculating the spectrum with higher precision.Comment: 46 pages, latex, 3 Postscript figures included, section on remaining
corrections added, title changed, error in older version corrected, cutoff
placed in a windo
Trapping of ultra-cold atoms with the magnetic field of vortices in a thin film superconducting micro-structure
We store and control ultra-cold atoms in a new type of trap using magnetic
fields of vortices in a high temperature superconducting micro-structure. This
is the first time ultra-cold atoms have been trapped in the field of magnetic
flux quanta. We generate the attractive trapping potential for the atoms by
combining the magnetic field of a superconductor in the remanent state with
external homogeneous magnetic fields. We show the control of crucial atom trap
characteristics such as an efficient intrinsic loading mechanism, spatial
positioning of the trapped atoms and the vortex density in the superconductor.
The measured trap characteristics are in good agreement with our numerical
simulations.Comment: 4pages, comments are welcom
Single-ion versus two-ion anisotropy in magnetic compounds: A neutron scattering study
Anisotropy effects can significantly control or modify the ground-state
properties of magnetic systems. Yet the origin and the relative importance of
the possible anisotropy terms is difficult to assess experimentally and often
ambiguous. Here we propose a technique which allows a very direct distinction
between single-ion and two-ion anisotropy effects. The method is based on
high-resolution neutron spectroscopic investigations of magnetic cluster
excitations. This is exemplified for manganese dimers and tetramers in the
mixed compounds CsMnxMg1-xBr3 (0.05\leqx\leq0.40). Our experiments provide
evidence for a pronounced anisotropy of the order of 3% of the dominant
bilinear exchange interaction, and the anisotropy is dominated by the
single-ion term. The detailed characterization of magnetic cluster excitations
offers a convenient way to unravel anisotropy effects in any magnetic material.Comment: 9 pages, 10 figures, 1 tabl
Emergence and rapid global dissemination of CTX-M-15-associated Klebsiella pneumoniae strain ST307
Abstract Recent reports indicate the emergence of a new carbapenemase producing Klebsiella pneumoniae clone, ST307. Here we show that ST307 emerged in the mid-1990s (nearly 20 years prior to its first report), is already globally distributed and is intimately associated with a conserved plasmid harbouring the bla CTX-M-15 extended-spectrum beta-lactamase (ESBL) gene plus other antimicrobial resistance determinants. Our findings support the need for enhanced surveillance of this widespread ESBL clone in which carbapenem resistance is now emerging
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