Acceleration by pulsar winds in binary systems

In the absence of accretion torques, a pulsar in a binary system will spin down due to electromagnetic dipole radiation and the spin-down power will drive a wind of relativistic electron-positron pairs. Winds from pulsars with short periods will prevent any subsequent accretion but may be confined by the companion star atmosphere, wind, or magnetosphere to form a standing shock. The authors investigate the possibility of particle acceleration at such a pulsar wind shock and the production of very high energy (VHE) and ultra high energy (UHE) gamma rays from interactions of accelerated protons in the companion star's wind or atmosphere. They find that in close binaries containing active pulsars, protons will be shock accelerated to a maximum energy dependent on the pulsar spin-down luminosity. If a significant fraction of the spin-down power goes into particle acceleration, these systems should be sources of VHE and possibly UHE gamma rays. The authors discuss the application of the pulsar wind model to binary sources such as Cygnus X-3, as well as the possibility of observing VHE gamma-rays from known binary radio pulsar systems

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

Magnetic aspects of QCD at finite density and temperature

Some magnetic aspects of QCD are discussed at finite density and temperature. Possibility of spontaneous magnetization is studied within Landau Fermi-liquid theory, and the important roles of the screening effects for gluon propagation are elucidated. Static screening for the longitudinal gluons improves the infrared singularities, while the transverse gluons receive only dynamic screening. The latter property gives rise to a novel non-Fermi-liquid behaviour for the magnetic susceptibility. Appearance of a density-wave state is also discussed in relation to chiral transition, where pseudoscalar condensate as well as scalar one takes a spatially non-uniform form in a chirally invariant way. Accordingly magnetization of quark matter oscillates like spin density wave. A hadron-quark continuity is suggested in this aspect, remembering pion condensation in hadronic phase.Comment: 6 pages, 8 figures, Proc. of INPN2010 to appear in J. Phy