The Sphaleron Rate in SU(N) Gauge Theory

The sphaleron rate is defined as the diffusion constant for topological number NCS = int g^2 F Fdual/32 pi^2. It establishes the rate of equilibration of axial light quark number in QCD and is of interest both in electroweak baryogenesis and possibly in heavy ion collisions. We calculate the weak-coupling behavior of the SU(3) sphaleron rate, as well as making the most sensible extrapolation towards intermediate coupling which we can. We also study the behavior of the sphaleron rate at weak coupling at large Nc.Comment: 18 pages with 3 figure

Jet coherence in QCD media: the antenna radiation spectrum

We study the radiation of a highly energetic partonic antenna in a colored state traversing a dense QCD medium. Resumming multiple scatterings of all involved constituents with the medium we derive the general gluon spectrum which encompasses both longitudinal color coherence between scattering centers in the medium, responsible for the well known Landau-Pomeranchuk-Migdal (LPM) effect, and transverse color coherence between partons inside a jet, leading, in vacuum, to angular ordering of the parton shower. We discuss shortly the onset of transverse decoherence which is reached in opaque media. In this regime, the spectrum consists of independent radiation off the antenna constituents.Comment: 15 pages, 2 figures, paper shortened and partly rewritten, references added, results unchange

Bjorken Flow, Plasma Instabilities, and Thermalization

At asymptotically high energies, thermalization in heavy ion collisions can be described via weak-coupling QCD. We present a complete treatment of how thermalization proceeds, at the parametric weak-coupling level. We show that plasma instabilities dominate the dynamics, from immediately after the collision until well after the plasma becomes nearly in equilibrium. Initially they drive the system close to isotropy, but Bjorken expansion and increasing diluteness makes the system again become more anisotropic. At time \tau ~ \alpha^(-12/5) Q^(-1) the dynamics become dominated by a nearly-thermal bath; and at time \tau ~ \alpha^(-5/2) Q^(-1)$ the bath comes to dominate the energy density, completing thermalization. After this time there is a nearly isotropic and thermal Quark-Gluon Plasma.Comment: 22 pages, 5 figure

Anomalous Breaking of Anisotropic Scaling Symmetry in the Quantum Lifshitz Model

In this note we investigate the anomalous breaking of anisotropic scaling symmetry in a non-relativistic field theory with dynamical exponent z=2. On general grounds, one can show that there exist two possible "central charges" which characterize the breaking of scale invariance. Using heat kernel methods, we compute these two central charges in the quantum Lifshitz model, a free field theory which is second order in time and fourth order in spatial derivatives. We find that one of the two central charges vanishes. Interestingly, this is also true for strongly coupled non-relativistic field theories with a geometric dual described by a metric and a massive vector field.Comment: 26 pages; major revision (results were unaffected), published versio

Prescribing practices of primary-care veterinary practitioners in dogs diagnosed with bacterial pyoderma

Concern has been raised regarding the potential contributions of veterinary antimicrobial use to increasing levels of resistance in bacteria critically important to human health. Canine pyoderma is a frequent, often recurrent diagnosis in pet dogs, usually attributable to secondary bacterial infection of the skin. Lesions can range in severity based on the location, total area and depth of tissue affected and antimicrobial therapy is recommended for resolution. This study aimed to describe patient signalment, disease characteristics and treatment prescribed in a large number of UK, primary-care canine pyoderma cases and to estimate pyoderma prevalence in the UK vet-visiting canine population

The Bulk Channel in Thermal Gauge Theories

We investigate the thermal correlator of the trace of the energy-momentum tensor in the SU(3) Yang-Mills theory. Our goal is to constrain the spectral function in that channel, whose low-frequency part determines the bulk viscosity. We focus on the thermal modification of the spectral function, $\rho(\omega,T)-\rho(\omega,0)$. Using the operator-product expansion we give the high-frequency behavior of this difference in terms of thermodynamic potentials. We take into account the presence of an exact delta function located at the origin, which had been missed in previous analyses. We then combine the bulk sum rule and a Monte-Carlo evaluation of the Euclidean correlator to determine the intervals of frequency where the spectral density is enhanced or depleted by thermal effects. We find evidence that the thermal spectral density is non-zero for frequencies below the scalar glueball mass $m$ and is significantly depleted for $m\lesssim\omega\lesssim 3m$.Comment: (1+25) pages, 6 figure

Three-loop HTL QCD thermodynamics

The hard-thermal-loop perturbation theory (HTLpt) framework is used to calculate the thermodynamic functions of a quark-gluon plasma to three-loop order. This is the highest order accessible by finite temperature perturbation theory applied to a non-Abelian gauge theory before the high-temperature infrared catastrophe. All ultraviolet divergences are eliminated by renormalization of the vacuum, the HTL mass parameters, and the strong coupling constant. After choosing a prescription for the mass parameters, the three-loop results for the pressure and trace anomaly are found to be in very good agreement with recent lattice data down to $T \sim 2-3\,T_c$, which are temperatures accessible by current and forthcoming heavy-ion collision experiments.Comment: 27 pages, 11 figures; corresponds with published version in JHE

Thermal photons in QGP and non-ideal effects

We investigate the thermal photon production-rates using one dimensional boost-invariant second order relativistic hydrodynamics to find proper time evolution of the energy density and the temperature. The effect of bulk-viscosity and non-ideal equation of state are taken into account in a manner consistent with recent lattice QCD estimates. It is shown that the \textit{non-ideal} gas equation of state i.e $\epsilon-3\,P\,\neq 0$ behaviour of the expanding plasma, which is important near the phase-transition point, can significantly slow down the hydrodynamic expansion and thereby increase the photon production-rates. Inclusion of the bulk viscosity may also have similar effect on the hydrodynamic evolution. However the effect of bulk viscosity is shown to be significantly lower than the \textit{non-ideal} gas equation of state. We also analyze the interesting phenomenon of bulk viscosity induced cavitation making the hydrodynamical description invalid. We include the viscous corrections to the distribution functions while calculating the photon spectra. It is shown that ignoring the cavitation phenomenon can lead to erroneous estimation of the photon flux.Comment: 11 pages, 13 figures; accepted for publication in JHE

Traditional, complementary and alternative medicine use in Sub-Saharan Africa: A systematic review

© Author(s) (or their employer(s)) 2018. background The WHO estimates that a considerable number of people in Sub-Saharan Africa (SSA) rely on traditional, complementary and alternative medicine (TCAM) to meet their primary healthcare needs, yet there remains a dearth of research evidence on the overall picture of TCAM utilisation in the region. Methods We conducted a literature search of original articles examining TCAM use in SSA between 1 January 2006 and 28 February 2017, employing Medline, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Scopus, ProQuest, PubMed, Embase and African Journals Online databases. A critical appraisal of relevant articles reporting a quantitative or mixed-method design was undertaken. results Despite the heterogeneity and general low quality of the identified literature, the review highlights a relatively high use of TCAM alone or in combination with orthodox medicine, in both general population and in specific health conditions in SSA. TCAM users compared with non-TCAM users are more likely to be of low socioeconomic and educational status, while there were inconsistencies in age, sex, spatial location and religious affiliation between TCAM users and non-TCAM users. Most TCAM users (55.8%–100%) in SSA fail to disclose TCAM use to their healthcare providers, with the main reasons for non-disclosure being fear of receiving improper care, healthcare providers’ negative attitude and a lack of enquiry about TCAM use from healthcare providers. Conclusion TCAM use in SSA is significant, although most studies emerge from a few countries. Factors associated with TCAM use in SSA are similar to those observed in other regions, but further research may be required to further elucidate challenges and opportunities related to TCAM use specific to SSA

Utilisation of and attitude towards traditional and complementary medicine among ebola survivors in sierra leone

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Background and objectives: In addition to conventional healthcare, Ebola survivors are known to seek traditional and complementary healthcare (T&CM) options to meet their healthcare needs. However, little is known about the general beliefs of Ebola survivors regarding T&CM and the impact of these beliefs in influencing their decisions around T&CM use. This study examines Ebola survivors’ attitudes towards T&CM use in Sierra Leone. Materials and Methods: We conducted a nationwide quantitative cross-sectional study of 358 Ebola survivors in Sierra Leone between January and August 2018. We used descriptive analysis, chi-square tests and backward stepwise binary logistic regression for data analysis. Results: Close to half of the survivors (n = 163, 45.5%) had used T&CM since their discharge from an Ebola treatment centre. Survivors who viewed T&CM as boosting their immune system/resistance were 3.89 times (95%CI: 1.57–9.63, p = 0.003) more likely to use T&CM than those who did not view T&CM as boosting their immune system/resistance. Additionally, survivors who viewed T&CM as having fewer side effects than conventional medicine were more likely to use T&CM [OR = 5.03 (95%CI: 1.92–13.19, p = 0.001)]. Ebola survivors were more influenced to use T&CM based on their personal experience of the effectiveness of T&CM than by clinical evidence [OR = 13.72 (95%CI: 6.10–30.84, P < 0.001)]. Ebola survivors who perceived T&CM as providing them with more control than conventional medicine over their health/body were more likely to use T&CM [OR = 4.15 (95%CI: 1.74–9.89, p = 0.001)] as opposed to those who did not perceive T&CM in this way. Conclusions: Considering the widespread use of T&CM, an understanding of Ebola survivors’ attitudes/beliefs towards T&CM is useful to healthcare providers and policymakers with regard to public education and practitioner–survivors communication, T&CM regulation and research in Sierra Leone. Ebola survivors appear to turn to T&CM not only for treatment, but also to fill gaps in conventional health care services