Elasticity, fluctuations and vortex pinning in ferromagnetic superconductors: A "columnar elastic glass"

We study the elasticity, fluctuations and pinning of a putative spontaneous vortex solid in ferromagnetic superconductors. Using a rigorous thermodynamic argument, we show that in the idealized case of vanishing crystalline pinning anisotropy the long-wavelength tilt modulus of such a vortex solid vanishes identically, as guaranteed by the underlying rotational invariance. The vanishing of the tilt modulus means that, to lowest order, the associated tension elasticity is replaced by the softer, curvature elasticity. The effect of this is to make the spontaneous vortex solid qualitatively more susceptible to the disordering effects of thermal fluctuations and random pinning. We study these effects, taking into account the nonlinear elasticity, that, in three dimensions, is important at sufficiently long length scales, and showing that a ``columnar elastic glass'' phase of vortices results. This phase is controlled by a previously unstudied zero-temperature fixed point and it is characterized by elastic moduli that have universal strong wave-vector dependence out to arbitrarily long length scales, leading to non-Hookean elasticity. We argue that, although translationally disordered for weak disorder, the columnar elastic glass is stable against the proliferation of dislocations and is therefore a topologically ordered {\em elastic} glass. As a result, the phenomenology of the spontaneous vortex state of isotropic magnetic superconductors differs qualitatively from a conventional, external-field-induced mixed state. For example, for weak external fields $H$, the magnetic induction scales {\em universally} like $B(H)\sim B(0)+ c H^{\alpha}$, with $\alpha\approx 0.72$.Comment: Minor editorial changes, version to be published in PRB, 39 pages, 7 figure

"Soft" Anharmonic Vortex Glass in Ferromagnetic Superconductors

Ferromagnetic order in superconductors can induce a {\em spontaneous} vortex (SV) state. For external field ${\bf H}=0$, rotational symmetry guarantees a vanishing tilt modulus of the SV solid, leading to drastically different behavior than that of a conventional, external-field-induced vortex solid. We show that quenched disorder and anharmonic effects lead to elastic moduli that are wavevector-dependent out to arbitrarily long length scales, and non-Hookean elasticity. The latter implies that for weak external fields $H$, the magnetic induction scales {\em universally} like $B(H)\sim B(0)+ c H^{\alpha}$, with $\alpha\approx 0.72$. For weak disorder, we predict the SV solid is a topologically ordered vortex glass, in the ``columnar elastic glass'' universality class.Comment: minor corrections; version published in PR

Book reviews

Teaching/Communication/Extension/Profession,

Application of the COM-B model to barriers and facilitators to chlamydia testing in general practice for young people and primary care practitioners: a systematic review

Background Chlamydia is a major public health concern, with high economic and social costs. In 2016, there were over 200,000 chlamydia diagnoses made in England. The highest prevalence rates are found among young people. Although annual testing for sexually active young people is recommended, many do not receive testing. General practice is one ideal setting for testing, yet attempts to increase testing in this setting have been disappointing. The Capability, Opportunity, and Motivation Model of Behaviour (COM-B model) may help improve understanding of the underpinnings of chlamydia testing. The aim of this systematic review was to (1) identify barriers and facilitators to chlamydia testing for young people and primary care practitioners in general practice and (2) map facilitators and barriers onto the COM-B model. Methods Qualitative, quantitative, and mixed methods studies published after 2000 were included. Seven databases were searched to identify peer-reviewed publications which examined barriers and facilitators to chlamydia testing in general practice. The quality of included studies was assessed using the Critical Appraisal Skills Programme. Data (i.e., participant quotations, theme descriptions, and survey results) regarding study design and key findings were extracted. The data was first analysed using thematic analysis, following this, the resultant factors were mapped onto the COM-B model components. All findings are reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results Four hundred eleven papers were identified; 39 met the inclusion criteria. Barriers and facilitators were identified at the patient (e.g., knowledge), provider (e.g., time constraints), and service level (e.g., practice nurses). Factors were categorised into the subcomponents of the model: physical capability (e.g., practice nurse involvement), psychological capability (e.g.: lack of knowledge), reflective motivation (e.g., beliefs regarding perceived risk), automatic motivation (e.g., embarrassment and shame), physical opportunity (e.g., time constraints), social opportunity (e.g., stigma). Conclusions This systematic review provides a synthesis of the literature which acknowledges factors across multiple levels and components. The COM-B model provided the framework for understanding the complexity of chlamydia testing behaviour. While we cannot at this juncture state which component represents the most salient influence on chlamydia testing, across all three levels, multiple barriers and facilitators were identified relating psychological capability and physical and social opportunity. Implementation should focus on (1) normalisation, (2) communication, (3) infection-specific information, and (4) mode of testing. In order to increase chlamydia testing in general practice, a multifaceted theory- and evidence-based approach is needed

The impacts of changes in agricultural policies in the United Kingdom on trade and agriculture especially in New Zealand – the WTO option

The United Kingdom’s (UK) exit from the European Union (EU) will have a range of implications for the UK, the EU and other countries like New Zealand (NZ). The nature and extent of its impacts will be determined by the terms under which the UK exits, hence the impact of Brexit is yet unknown. This study assessed how the agricultural sector in the UK, the EU and NZ would be affected if the UK does not reach a trade agreement with the EU by 31st October 2019, then by default, the UK will have to comply with the WTO rules to trade with the EU, and third countries. The Lincoln Trade and Environment Model (LTEM), a partial equilibrium trade model that simulates international trade, production and consumption of agricultural commodities was used for the analysis. A WTO scenario was developed applying trade weighted outbound facing MFN (WTO) tariffs to imports from the EU and other third countries. In addition, the change in trade facilitation costs was set at 10 per cent. Modelling results showed a large impact on UK’s production and consumption of agricultural goods while the agricultural sector in the EU and NZ would be only slightly affected by this trade policy. However, the UK leaving the EU could work to strengthen the trading relationship with NZ depending on the UK’s access to the EU’s Single Marke

The Short- and Long-Run Effects of Private Law Enforcement: Evidence from University Police

Over a million people in the United States are employed in private security and law enforcement, yet very little is known about the effects of private police on crime. The current study examines the relationship between a privately-funded university police force and crime in a large U.S. city. Following an expansion of the jurisdictional boundary of the private police force, we see no short-term change in crime. However, using a geographic regression discontinuity approach, we find large impacts of private police on public safety, with violent crime in particular decreasing. These contradictory results appear to be a consequence of delayed effect of private police on crime

Parents\u27 Perception of their Children\u27s Asthma, 2002-2008: A Community-Based Study

Childhood asthma is a chronic health condition that is one of the leading causes of hospitalizations and missed school days for children. It also affects the lives of both asthmatic children and their families

Examining the potential public health benefit of offering STI testing to men in amateur football clubs: evidence from cross-sectional surveys

Background: In Britain, young people continue to bear the burden of sexually transmitted infections (STIs) so efforts are required, especially among men, to encourage STI testing. The SPORTSMART study trialled an intervention that sought to achieve this by offering chlamydia and gonorrhoea test-kits to men attending amateur football clubs between October and December 2012. With football the highest participation team sport among men in England, this paper examines the potential public health benefit of offering STI testing to men in this setting by assessing their sociodemographic characteristics, sexual behaviours, and healthcare behaviour and comparing them to men in the general population. Methods: Data were collected from 192 (male) members of 6 football clubs in London, United Kingdom, aged 18–44 years via a 20-item pen-and-paper self-completion questionnaire administered 2 weeks after the intervention. These were compared to data collected from 409 men of a similar age who were resident in London when interviewed during 2010–2012 for the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), a national probability survey that used computer-assisted-personal-interviewing with computer-assisted-self-interview. Age standardisation and multivariable regression were used to account for sociodemographic differences between the surveys. Results: Relative to men in the general population, SPORTSMART men were younger (32.8 % vs. 21.7 % aged under 25 y), and more likely to report (all past year) at least 2 sexual partners (adjusted odds ratio, AOR: 3.25, 95 % CI: 2.15–4.92), concurrent partners (AOR: 2.05, 95 % CI: 1.39–3.02), and non-use of condoms (AOR: 2.17, 95 % CI: 1.39–3.41). No difference was observed in STI/HIV risk perception (AOR for reporting “not at all at risk” of STIs: 1.25, 95 % CI: 0.76–2.04; of HIV: AOR: 1.54, 95 % CI: 0.93–2.55), nor in reporting STI testing in the past year (AOR: 0.83, 95 % CI: 0.44–1.54), which was reported by only one in six men. Conclusions: Relative to young men in the general population, football club members who completed the SPORTSMART survey reported greater sexual risk behaviour but similar STI/HIV risk perception and STI testing history. Offering STI testing in amateur football clubs may therefore widen access to STI testing and health promotion messages for men at higher STI risk, which, given the minority currently testing and the popularity of football in England, should yield both individual and public health benefit

Where is the best site on Earth? Domes A, B, C and F, and Ridges A and B

The Antarctic plateau contains the best sites on earth for many forms of astronomy, but none of the existing bases was selected with astronomy as the primary motivation. In this article, we try to systematically compare the merits of potential observatory sites.We include South Pole, Domes A, C, and F, and also Ridge B (running northeast from Dome A), and what we call "Ridge A" (running southwest from Dome A). Our analysis combines satellite data, published results, and atmospheric models, to compare the boundary layer, weather, aurorae, airglow, precipitable water vapor, thermal sky emission, surface temperature, and the free atmosphere, at each site. We find that all Antarctic sites are likely to be compromised for optical work by airglow and aurorae. Of the sites with existing bases, Dome A is easily the best overall; but we find that Ridge A offers an even better site. We also find that Dome F is a remarkably good site. Dome C is less good as a thermal infrared or terahertz site, but would be able to take advantage of a predicted "OH hole" over Antarctica during spring.Comment: Revised version. 16 pages, 21 figures (22 in first version). Submitted to PASP 16/05/09, accepted 13/07/09; published 20/08/0