Quantised vortices and mutual friction in relativistic superfluids

We consider the detailed dynamics of an array of quantised superfluid vortices in the framework of general relativity, as required for quantitative modelling of realistic neutron star cores. Our model builds on the variational approach to relativistic (multi-) fluid dynamics, where the vorticity plays a central role. The description provides a natural extension of, and as it happens a better insight into, existing Newtonian models. In particular, we account for the mutual friction associated with scattering of a second "normal" component in the mixture off of the superfluid vortices.Comment: 9 pages, RevTe

Can a charged dust ball be sent through the Reissner--Nordstr\"{o}m wormhole?

In a previous paper we formulated a set of necessary conditions for the spherically symmetric weakly charged dust to avoid Big Bang/Big Crunch, shell crossing and permanent central singularities. However, we did not discuss the properties of the energy density, some of which are surprising and seem not to have been known up to now. A singularity of infinite energy density does exist -- it is a point singularity situated on the world line of the center of symmetry. The condition that no mass shell collapses to $R = 0$ if it had $R > 0$ initially thus turns out to be still insufficient for avoiding a singularity. Moreover, at the singularity the energy density $\epsilon$ is direction-dependent: $\epsilon \to - \infty$ when we approach the singular point along a $t =$ const hypersurface and $\epsilon \to + \infty$ when we approach that point along the center of symmetry. The appearance of negative-energy-density regions turns out to be inevitable. We discuss various aspects of this property of our configuration. We also show that a permanently pulsating configuration, with the period of pulsation independent of mass, is possible only if there exists a permanent central singularity.Comment: 30 pages, 21 figures; several corrections after referee's comments, 4 figures modifie

On the Geroch-Traschen class of metrics

We compare two approaches to semi-Riemannian metrics of low regularity. The maximally 'reasonable' distributional setting of Geroch and Traschen is shown to be consistently contained in the more general setting of nonlinear distributional geometry in the sense of Colombea

Systematic review and meta-analysis of the sero-epidemiological association between Epstein-Barr virus and rheumatoid arthritis

Acknowledgements The authors would like to thank Cynthia Fraser for helping run the literature search, Dr Neil Basu for providing advice on search terms for rheumatoid arthritis and to Xueli Jia, Katie Bannister and Kubra Boza for their help with foreign language papers. The authors would also like to thank the University of Aberdeen librarians at the Foresterhill medical library for their help in locating articles used for this systematic review and meta-analysis.Peer reviewedPublisher PD

New light on Galactic post-asymptotic giant branch stars. I. First distance catalogue

We have commenced a detailed analysis of the known sample of Galactic post-asymptotic giant branch (PAGB) objects compiled in the Toru\'n catalogue of Szczerba et al., and present, for the first time, homogeneously derived distance determinations for the 209 likely and 87 possible catalogued PAGB stars from that compilation. Knowing distances are essential in determining meaningful physical characteristics for these sources and this has been difficult to determine for most objects previously. The distances were determined by modelling their spectral energy distributions (SED) with multiple black-body curves, and integrating under the overall fit to determine the total distance-dependent flux. This method works because the luminosity of these central stars is very nearly constant from the tip of the AGB phase to the beginning of the white-dwarf cooling track. This then enables us to use a standard-candle luminosity to estimate the SED distances. For Galactic thin disk PAGB objects, we use three luminosity bins based on typical observational characteristics, ranging between 3500 and 12000 L_sun. We further adopt a default luminosity of 1700 L_sun for all halo PAGB objects. We have also applied the above technique to a further sample of 69 related nebulae not in the current edition of the Toru\'n catalogue. In a follow-up paper we will estimate distances to the subset of RV Tauri variables using empirical period-luminosity relations, and to the R\,CrB stars, allowing a population comparison of these objects with the other subclasses of PAGB stars for the first time.Comment: 24 pages, 8 tables, 4 figures. Submitted to MNRAS. Appendix B containing full list of SED figures excluded in this versio

Legitimation, performativity and the tyranny of a ‘hijacked’ word

Outstanding education is a high level policy narrative in England rehearsed by school leaders, politicians, policy makers and inspectors alike. Lyotard’s (1979) work on the 'legitimacy' of knowledge and performativity, and Foucauldian discourse-based analysis (1972, 1991), are mobilised to examine outstanding. The paper explores how informants in the English state secondary education sector described and experienced outstanding. From examining policy documents and empirical data, the paper suggests that outstanding has become a performative tool "hijacked" by inspection regimes. It concludes that, despite the informants' best efforts, the neo-liberal and performative policy discourses which surround outstanding appear to increasingly wield a disproportionate, even tyrannical, influence upon the English education system

Feasibility Testing of the Alert for AFib Intervention.

Improving early detection and treatment of atrial fibrillation (AF) is critical because untreated AF is a major contributor to stroke and heart failure. We sought to generate knowledge about the feasibility of conducting a randomized controlled trial to test the effect of the Alert for AFib intervention on knowledge, attitudes, and beliefs about treatment-seeking for signs and symptoms of AF. Adults ≥65 years old (96% White) at risk for developing AF were randomized to receive the Alert for AFib intervention ( n = 40) or an attention control session ( n = 40). Feasibility goals for recruitment, participant retention, adherence, perceived satisfaction and burden, and intervention fidelity were met. From baseline to study completion, knowledge ( p = .005) and attitudes ( p < .001) about treatment-seeking improved more in the intervention group compared with the control group. Results support testing the effectiveness of the Alert for AFib intervention in a large trial