General practice registrars’ intentions for future practice: Implications for rural medical workforce planning

The models of practice that general practice registrars (GPRs) envisage undertaking will affect workforce supply. The aim of this research was to determine practice intentions of current GPRs in a regional general practice training program (Coast City Country General Practice Training). Questionnaires were circulated to 220 GPRs undertaking general practice placements to determine characteristics of ideal practice models and intentions for future practice. Responses were received for 99 participants (45%). Current GPRs intend to work an average of less than eight half-day sessions/week, with male participants intending to work more hours (t(91) = 3.528, P = 0.001). More than one-third of this regional cohort intends to practice in metropolitan centres. Proximity to family and friends was the most important factor influencing the choice of practice location. Men ranked remuneration for work as more important (t (88) = –4.280, P \u3c 0.001) and women ranked the ability to work part-time higher (t(94) = 3.697, P \u3c 0.001). Fee-for-service payment alone, or in combination with capitation, was the preferred payment system. Only 22% of Australian medical graduates intend to own their own practice compared with 52% of international medical graduates (χ2(1) = 8.498, P = 0.004). Future general practitioners (GPs) intend to work fewer hours than current GPs. Assumptions about lifestyle factors, practice models and possible professional roles should be carefully evaluated when developing strategies to recruit GPs and GPRs into rural practice

Modeling the Pulse Profiles of Millisecond Pulsars in the Second LAT Catalog of gamma-ray Pulsars

Significant gamma-ray pulsations have been detected from ~40 millisecond pulsars (MSPs) using 3 years of sky-survey data from the Fermi LAT and radio timing solutions from across the globe. We have fit the radio and gamma-ray pulse profiles of these MSPs using geometric versions of slot gap and outer gap gamma-ray emission models and radio cone and core models. For MSPs with radio and gamma-ray peaks aligned in phase we also explore low-altitude slot gap gamma-ray models and caustic radio models. The best-fit parameters provide constraints on the viewing geometries and emission sites. While the exact pulsar magnetospheric geometry is unknown, we can use the increased number of known gamma-ray MSPs to look for significant trends in the population which average over these uncertainties.Comment: 4 pages, 2 figures, to appear in the proceedings of the 5th International Symposium on High-Energy Astronom

Report on a cryogenic gyroscope

Report summarizes the principal problems encountered in sphere fabrication, magnetic field losses in superconductors, configurations for the supporting field, damping oscillations, refrigeration, techniques for accelerating the sphere, read-out, and testing the stability of the gyro

The Effect of Different Magnetospheric Structures on Predictions of Gamma-ray Pulsar Light Curves

The second pulsar catalogue of the Fermi Large Area Telescope (LAT) will contain in excess of 100 gamma-ray pulsars. The light curves (LCs) of these pulsars exhibit a variety of shapes, and also different relative phase lags with respect to their radio pulses, hinting at distinct underlying emission properties (e.g., inclination and observer angles) for the individual pulsars. Detailed geometric modelling of the radio and gamma-ray LCs may provide constraints on the B-field structure and emission geometry. We used different B-field solutions, including the static vacuum dipole and the retarded vacuum dipole, in conjunction with an existing geometric modelling code, and constructed radiation sky maps and LCs for several different pulsar parameters. Standard emission geometries were assumed, namely the two-pole caustic (TPC) and outer gap (OG) models. The sky maps and LCs of the various B-field and radiation model combinations were compared to study their effect on the resulting LCs. As an application, we compared our model LCs with Fermi LAT data for the Vela pulsar, and inferred the most probable configuration in this case, thereby constraining Vela's high-altitude magnetic structure and system geometry.Comment: 6 pages, 4 figures, conference article, appears in Proceedings of SAIP2012, the 57th Annual Conference of the South African Institute of Physics, edited by Johan Janse van Rensburg, ISBN: 978-1-77592-070-

Constraining viewing geometries of pulsars with single-peaked gamma-ray profiles using a multiwavelength approach

Since the launch of the Large Area Telescope (LAT) on board the Fermi spacecraft in June 2008, the number of observed gamma-ray pulsars has increased dramatically. A large number of these are also observed at radio frequencies. Constraints on the viewing geometries of 5 of 6 gamma-ray pulsars exhibiting single-peaked gamma-ray profiles were derived using high-quality radio polarization data (Weltevrede et al., 2010). We obtain independent constraints on the viewing geometries of 6 by using a geometric emission code to model the Fermi LAT and radio light curves (LCs). We find fits for the magnetic inclination and observer angles by searching the solution space by eye. Our results are generally consistent with those previously obtained (Weltevrede et al., 2010), although we do find small differences in some cases. We will indicate how the gamma-ray and radio pulse shapes as well as their relative phase lags lead to constraints in the solution space. Values for the flux correction factor corresponding to the fits are also derived (with errors).Comment: 6 pages, 2 figures, 1 table, Proceedings of SAIP2011, the 56th Annual Conference of the South African Institute of Physics (ISBN: 978-1-86888-688-3), ed. I. Basson and A. E. Botha, http://www.saip.org.za, pp. 531-53

The cryogenic gyroscope program at Jet Propulsion Laboratory Final report

Cryogenic gyroscope with spinning superconducting sphere levitated in vacuum by magnetic fiel

High Energy Neutrinos and Photons from Curvature Pions in Magnetars

We discuss the relevance of the curvature radiation of pions in strongly magnetized pulsars or magnetars, and their implications for the production of TeV energy neutrinos detectable by cubic kilometer scale detectors, as well as high energy photons.Comment: 19 pages, 4 figures, to appear in JCA

Inhomogeneity in the Supernova Remnant Distribution as the Origin of the PAMELA Anomaly

Recent measurements of the positron/electron ratio in the cosmic ray (CR) flux exhibits an apparent anomaly, whereby this ratio increases between 10 and 100 GeV. We show that inhomogeneity of CR sources on a scale of order a kpc, can naturally explain this anomaly. If the nearest major CR source is about a kpc away, then low energy electrons ($\sim 1$ GeV) can easily reach us. At higher energies ($\gtrsim 10$ GeV), the source electrons cool via synchrotron and inverse-Compton before reaching Earth. Pairs formed in the local vicinity through the proton/ISM interactions can reach Earth also at high energies, thus increasing the positron/electron ratio. A natural origin of source inhomogeneity is the strong concentration of supernovae in the galactic spiral arms. Assuming supernova remnants (SNRs) as the sole primary source of CRs, and taking into account their concentration near the galactic spiral arms, we consistently recover the observed positron fraction between 1 and 100 GeV. ATIC's electron excess at $\sim 600$ GeV is explained, in this picture, as the contribution of a few known nearby SNRs. The apparent coincident similarity between the cooling time of electrons at 10 GeV (where the positron/electron ratio upturn), $\sim 10$ Myr, and the CRs protons cosmogenic age at the same energy is predicted by this model