Electromagnetic Fields of Slowly Rotating Magnetized Gravastars

We study the dipolar magnetic field configuration and present solutions of Maxwell equations in the internal background spacetime of a a slowly rotating gravastar. The shell of gravastar where magnetic field penetrated is modeled as sphere consisting of perfect highly magnetized fluid with infinite conductivity. Dipolar magnetic field of the gravastar is produced by a circular current loop symmetrically placed at radius $a$ at the equatorial plane.Comment: 5 pages, 2 figures, accepted for publication to Mod. Phys. Lett.

The chemical composition and nutritive value of Australian pulses

Grain legumes are the harvested seed of leguminous crops, typically peas, beans and their close relatives within the Fabaceae. Another term for many of these crops is pulses. In Australia, generally grain legumes are referred to as pulses. The term pulse is derived from the Latin puls meaning that the seed or grain can be made into a thick soup or pottage. The term pulse is most commonly associated with the food legumes whereas grain legumes are mostly associated with the feed industry. The terms are interchangeable, but with few exceptions (notably chickpeas, lentils and mung beans), the majority of the crops are used for animal feed. Both soybeans and peanuts are leguminous plants; however they are traditionally regarded as oilseed crops, and will not be discussed here.https://researchlibrary.agric.wa.gov.au/books/1020/thumbnail.jp

An FTIR spectrometer for remote measurements of atmospheric composition

The JPL IV interferometer, and infrared Michelson interferometer, was built specifically for recording high resolution solar absorption spectra from remote ground-based sites, aircraft and from stratospheric balloons. The instrument is double-passed, with one fixed and one moving corner reflector, allowing up to 200-cm of optical path difference (corresponding to an unapodised spectral resolution of 0.003/cm). The carriage which holds the moving reflector is driven by a flexible nut riding on a lead screw. This arrangement, together with the double-passed optical scheme, makes the instrument resistant to the effects of mechanical distortion and shock. The spectral range of the instrument is covered by two liquid nitrogen-cooled detectors: an InSb photodiode is used for the shorter wavelengths (1.85 to 5.5 microns, 1,800 to 5,500/cm) and a HgCdTe photoconductor for the range (5.5 to 15 microns, 650 to 1,800/cm). For a single spectrum of 0.01/cm resolution, which requires a scan time of 105 seconds, the signal/noise ratio is typically 800:1 over the entire wavelength range

A Toy Model for Blandford-Znajek Mechanism

A toy model for the Blandford-Znajek mechanism is investigated: a Kerr black hole with a toroidal electric current residing in a thin disk around the black hole. The toroidal electric current generates a poloidal magnetic field threading the black hole and disk. Due to the interaction of the magnetic field with remote charged particles, the rotation of the black hole and disk induces an electromotive force, which can power an astrophysical load at remote distance. The power of the black hole and disk is calculated. It is found that, for a wide range of parameters specifying the rotation of the black hole and the distribution of the electric current in the disk, the power of the disk exceeds the power of the black hole. The torque provided by the black hole and disk is also calculated. The torque of the disk is comparable to the torque of the black hole. As the disk loses its angular momentum, the mass of the disk gradually drifts towards the black hole and gets accreted. Ultimately the power comes from the gravitational binding energy between the disk and the black hole, as in the standard theory of accretion disk, instead of the rotational energy of the black hole. This suggests that the Blandford-Znajek mechanism may be less efficient in extracting energy from a rotating black hole with a thin disk. The limitations of our simple model and possible improvements deserved for future work are also discussed.Comment: 16 pages, 4 figures. Accepted for publication in Physical Review

The evolution of a supermassive binary caused by an accretion disc

The interaction of a massive binary and a non-self-gravitating circumbinary accretion disc is considered. The shape of the stationary twisted disc produced by the binary is calculated. It is shown that the inner part of the disc must lie in the binary orbital plane for any value of viscosity. When the inner disc midplane is aligned with the binary orbital plane on the scales of interest and it rotates in the same sense as the binary, the modification of the disc structure and the rate of decay of the binary orbit, assumed circular, due to tidal exchange of angular momentum with the disc, are calculated. It is shown that the modified disc structure is well described by a self-similar solution of the non-linear diffusion equation governing the evolution of the disc surface density. The calculated time scale for decay of the binary orbit is always smaller than the "accretion" time $t_{acc}=m/{\dot M}$ ($m$ is the mass of the secondary component, and $\dot M$ is the disc accretion rate), and is determined by ratio of secondary mass $m$, assumed to be much smaller than the primary mass, the disc mass inside the initial binary orbit, and the form of viscosity in the disc.Comment: to be published in MNRA

The effect of self-selected complementary therapies on cancer patients\u27 quality of life and symptom distress: A prospective cohort study in an integrative oncology setting

Objective: To examine the effectiveness of a multifaceted complementary therapies intervention, delivered in a systematic manner within an Australian public hospital setting, on quality of life and symptom distress outcomes for cancer patients. Methods: Adults receiving treatment for any form of cancer were eligible to participate in this study. Self-referred participants were offered a course of six complementary therapy sessions. Measures were administered at baseline, and at the third and sixth visit. The primary outcomes were quality of life and symptom distress. Linear mixed models were used to assess change in the primary outcomes. Results: In total, 1376 cancer patients participated in this study. The linear mixed models demonstrated that there were significant improvements in quality of life and significant reductions in symptom distress over six sessions. Body-based therapies demonstrated significantly superior improvement in quality of life over counselling, but no other differences between therapies were identified. Reduced symptom distress was not significantly associated with any particular type of therapy. Conclusion: A self-selected complementary therapies intervention, provided in an Australian public hospital by accredited therapists, for cancer patients significantly mproved quality of life and reduced symptom distress. The effect of this intervention on quality of life has particular salience, since cancer impacts on many areas of people’s lives and impairs quality of life

General Relativistic Electromagnetic Fields of a Slowly Rotating Magnetized Neutron Star. I. Formulation of the equations

We present analytic solutions of Maxwell equations in the internal and external background spacetime of a slowly rotating magnetized neutron star. The star is considered isolated and in vacuum, with a dipolar magnetic field not aligned with the axis of rotation. With respect to a flat spacetime solution, general relativity introduces corrections related both to the monopolar and the dipolar parts of the gravitational field. In particular, we show that in the case of infinite electrical conductivity general relativistic corrections due to the dragging of reference frames are present, but only in the expression for the electric field. In the case of finite electrical conductivity, however, corrections due both to the spacetime curvature and to the dragging of reference frames are shown to be present in the induction equation. These corrections could be relevant for the evolution of the magnetic fields of pulsars and magnetars. The solutions found, while obtained through some simplifying assumption, reflect a rather general physical configuration and could therefore be used in a variety of astrophysical situations.Comment: A few typos corrected; matches the versions in MNRA

Secular instability in quasi-viscous disc accretion

A first-order correction in the $\alpha$-viscosity parameter of Shakura and Sunyaev has been introduced in the standard inviscid and thin accretion disc. A linearised time-dependent perturbative study of the stationary solutions of this "quasi-viscous" disc leads to the development of a secular instability on large spatial scales. This qualitative feature is equally manifest for two different types of perturbative treatment -- a standing wave on subsonic scales, as well as a radially propagating wave. Stability of the flow is restored when viscosity disappears.Comment: 15 pages, 2 figures, AASTeX. Added some new material and upgraded the reference lis