Supergravity Instabilities of Non-Supersymmetric Quantum Critical Points

Motivated by the recent use of certain consistent truncations of M-theory to study condensed matter physics using holographic techniques, we study the SU(3)-invariant sector of four-dimensional, N=8 gauged supergravity and compute the complete scalar spectrum at each of the five non-trivial critical points. We demonstrate that the smaller SU(4)^- sector is equivalent to a consistent truncation studied recently by various authors and find that the critical point in this sector, which has been proposed as the ground state of a holographic superconductor, is unstable due to a family of scalars that violate the Breitenlohner-Freedman bound. We also derive the origin of this instability in eleven dimensions and comment on the generalization to other embeddings of this critical point which involve arbitrary Sasaki-Einstein seven manifolds. In the spirit of a resurging interest in consistent truncations, we present a formal treatment of the SU(3)-invariant sector as a U(1)xU(1) gauged N=2 supergravity theory coupled to one hypermultiplet.Comment: 46 page

Feasibility and evaluation of an emergency department‐based general practitioner streaming and treatment service

Rationale Offering a primary care service that can provide good quality primary care at emergency departments may reduce pressure on usual emergency department (ED) services. Aims and Objectives To evaluate the acceptability, satisfaction, and potential impacts of a co-located primary care service at an emergency department. Methods This is a prospective feasibility study and service evaluation comprising a narrative summary of activity, satisfaction, well-being, and safety, and comparisons of wait times for ED services by patient category (‘minor’, ‘majors’, ‘paediatric’ or ‘resus’) before and during the service operation. Patients and staff were asked using semistructured interview topic guides about service perception, well-being, representation within 48 h, safety concerns, and/or satisfaction. Wait times for patient categories in usual ED care service were in secondary care electronic records. Pathway changes were captured under primary care electronic records. Results Approximately 96% of general practitioner streaming and treatment (GPST) patients were seen within 1 h. There was a statistically significant reduction in ED patients with minor injuries or illnesses waiting >4 h for admission or discharge ‘breaches’ during the 3 months that GPST was operating compared with the previous 3 months (p ≤ 0.005). Wait times for other ED services did not significantly improve. A total of 769 walk-in patients received GPST consultation and 661 (86%) needed no further ED intervention. Fast discharge was a major determinant of patient satisfaction. No staff expressed dissatisfaction, but some suggested possible improvements in eligibility criteria and built environment design features. Conclusion Provision of GPST correlated with shorter waits for discharge from ED. Patient and staff experiences of GPST were positive

Equation-free implementation of statistical moment closures

We present a general numerical scheme for the practical implementation of statistical moment closures suitable for modeling complex, large-scale, nonlinear systems. Building on recently developed equation-free methods, this approach numerically integrates the closure dynamics, the equations of which may not even be available in closed form. Although closure dynamics introduce statistical assumptions of unknown validity, they can have significant computational advantages as they typically have fewer degrees of freedom and may be much less stiff than the original detailed model. The closure method can in principle be applied to a wide class of nonlinear problems, including strongly-coupled systems (either deterministic or stochastic) for which there may be no scale separation. We demonstrate the equation-free approach for implementing entropy-based Eyink-Levermore closures on a nonlinear stochastic partial differential equation.Comment: 7 pages, 2 figure

A harmonic family of dielectric flow solutions with maximal supersymmetry

We construct a new harmonic family: dielectric flow solutions with maximal supersymmetry in eleven-dimensional supergravity. These solutions are asymptotically AdS_4 x S^7, while in the infra-red the M2 branes are dielectrically polarized into M5 branes. These solutions are holographically dual to vacua of the mass deformed theory on M2 branes. They also provide an interesting insight on the supergravity solutions sourced by giant gravitons, allowing one to see how supergravity solves the giant graviton puzzle.Comment: 21 pages, LaTeX. reference adde

Should Native Pastures Be Fertilised?

Considerable research has been conducted in recent years demonstrating the ongoing benefits of phosphorus (P) fertiliser in achieving and maintaining higher levels of production from native pastures (Graham 2006; Garden et al. 2003; Lodge et al. 2003; Michalk et al. 2003). However Garden et al. (2003), Hill et al. (2004) and Dorrough et al. (2008) all question the sustainability of this practice by highlighting changes in species composition of these pastures with regard to increasing the introduced annual grass and broadleaf weed components at the expense of the native grasses and forbs but in most cases, these trends have been based on short term replicated data or based on qualitative survey data incapable of establishing causal relationships. In the Monaro region of NSW, 70% of pastures are based on native species and are the cornerstone of livestock production. The Monaro Research, Development and Demonstration of Sustainable Grassland Management Project (MGP) was designed to determine if productivity could be increased without compromising the composition and bio-diversity values of these pastures

Clustering of Dust-Obscured Galaxies at z ~ 2

We present the angular autocorrelation function of 2603 dust-obscured galaxies (DOGs) in the Bootes field of the NOAO Deep Wide-Field Survey. DOGs are red, obscured galaxies, defined as having R-[24] \ge 14 (F_24/F_R \ga 1000). Spectroscopy indicates that they are located at 1.5 \la z \la 2.5. We find strong clustering, with r_0 = 7.40^{+1.27}_{-0.84} Mpc/h for the full F_24 > 0.3 mJy sample. The clustering and space density of the DOGs are consistent with those of submillimeter galaxies, suggestive of a connection between these populations. We find evidence for luminosity-dependent clustering, with the correlation length increasing to r_0 = 12.97^{+4.26}_{-2.64} Mpc/h for brighter (F_24 > 0.6 mJy) DOGs. Bright DOGs also reside in richer environments than fainter ones, suggesting these subsamples may not be drawn from the same parent population. The clustering amplitudes imply average halo masses of log M = 12.2^{+0.3}_{-0.2} Msun for the full DOG sample, rising to log M = 13.0^{+0.4}_{-0.3} Msun for brighter DOGs. In a biased structure formation scenario, the full DOG sample will, on average, evolve into ~ 3 L* present-day galaxies, whereas the most luminous DOGs may evolve into brightest cluster galaxies.Comment: ApJL in press; 4 pages, 3 figures, 1 tabl

Mass and angular momenta of Kerr anti-de Sitter spacetimes in Einstein-Gauss-Bonnet theory

We compute the mass and angular momenta of rotating anti-de Sitter spacetimes in Einstein-Gauss-Bonnet theory of gravity using a superpotential derived from standard Noether identities. The calculation relies on the fact that the Einstein and Einstein-Gauss-Bonnet vacuum equations are the same when linearized on maximally symmetric backgrounds and uses the recently discovered D-dimensional Kerr-anti-de Sitter solutions to Einstein's equations