The temperature and entropy of CFT on time-dependent backgrounds

We express the AdS-Schwarzschild black-hole configuration in coordinates such that the boundary metric is of the FLRW type. We review how this construction can be used in order to calculate the stress-energy tensor of the dual CFT on the FLRW background. We deduce the temperature and entropy of the CFT, which are related to the temperature and entropy of the black hole. We find that the entropy is proportional to the area of an apparent horizon, different from the black-hole event horizon. For a dS boundary we reproduce correctly the intrinsic temperature of dS space.Comment: 19 pages, major revision, several comments added, version to appear in JHE

Entropy from AdS(3)/CFT(2)

We parametrize the (2+1)-dimensional AdS space and the BTZ black hole with Fefferman-Graham coordinates starting from the AdS boundary. We consider various boundary metrics: Rindler, static de Sitter and FRW. In each case, we compute the holographic stress-energy tensor of the dual CFT and confirm that it has the correct form, including the effects of the conformal anomaly. We find that the Fefferman-Graham parametrization also spans a second copy of the AdS space, including a second boundary. For the boundary metrics we consider, the Fefferman-Graham coordinates do not cover the whole AdS space. We propose that the length of the line delimiting the excluded region at a given time can be identified with the entropy of the dual CFT on a background determined by the boundary metric. For Rindler and de Sitter backgrounds our proposal reproduces the expected entropy. For a FRW background it produces a generalization of the Cardy formula that takes into account the vacuum energy related to the expansion.Comment: major revision with several clarifications and corrections, 22 page

Annealing temperatures affect 16S rRNA gene-amplicon Illumina sequencingbased bacterial community analysis of canine skin

Analysis of the bacterial community structure of dog skin samples, sequencing the 16S rRNA gene is nowadays widely used. Among others, the 16S rRNA gene amplicon Illumina sequencing technique is well established and routinely applied to get a first inside into the bacterial community diversity and taxonomic composition. However, as it is a molecular-based technique, bias due to methodology is possible and should be minimized. In this study, we tested the effects of annealing temperature (50°C vs 55°C) on the 16S rRNA gene amplicon analysis of the bacterial microbiota of skin and ear canal samples from a German shepherd dog. Although beta diversity was not affected by the higher annealing temperature, alpha diversity values showed a shift (overall diversity (Shannon) and evenness were increased, whereas dominance (D), number of taxa (S), richness (Chao 1) and the total numbers of individuals (N) were reduced, with higher annealing temperature). The biological relevance of this finding remains unclear. Thus, our results underline the importance of optimal annealing temperature in order to minimize bias, as well as the necessity of further similar studies with a larger sample size

Exploring the impact of public health teams on alcohol premises licensing in England and Scotland (ExILEnS): procotol for a mixed methods natural experiment evaluation.

Background: Recent regulatory changes in the system by which premises are licensed to sell alcohol, have given health representatives a formal role in the process in England and Scotland. The degree to which local public health teams engage with this process varies by locality in both nations, which have different licensing regimes. This study aims to critically assess the impact on alcohol-related harms - and mechanisms - of public health stakeholders’ engagement in alcohol premises licensing from 2012 to 2018, comparing local areas with differing types and intensities of engagement, and examining practice in Scotland and England. Methods: The study will recruit 20 local authority areas where public health stakeholders have actively engaged with the alcohol premises licensing system (the 'intervention’) and match them to a group of 20 lower activity areas using genetic matching. Four work packages are included: (1) Structured interviews and documentary analysis will examine the type and level of intervention activity from 2012 to 2018, creating a novel composite measure of the intensity of such activity and will assess the local licensing system and potential confounding activities over the same period. In-depth interviews with public health, licensing, police and others will explore perceived mechanisms of change, acceptability, and impact. (2) Using longitudinal growth models and time series analyses, the study will evaluate the impact of high and low levels of activity on alcohol-related harms using routine data from baseline 2009 to 2018. (3) Intervention costs, estimated National Health Service cost savings and health gains will be evaluated using the Sheffield Alcohol Policy Model to estimate impact on alcohol consumption and health inequalities. (4) The study will engage public health teams to create a new theory of change for public health involvement in the licensing process using our data. We will share findings with local, national and international stakeholders. Discussion: This interdisciplinary study examines, for the first time, whether and how public health stakeholders involvement in alcohol licensing impacts on alcohol harms. Using mixed methods and drawing on complex systems thinking, it will make an important contribution to an expanding literature evaluating interventions not suited to traditional epidemiological research

Equilibrium points of the tilted perfect fluid Bianchi VIh state space

We present the full set of evolution equations for the spatially homogeneous cosmologies of type VIh filled with a tilted perfect fluid and we provide the corresponding equilibrium points of the resulting dynamical state space. It is found that only when the group parameter satisfies h > -1 a self-similar solution exists. In particular we show that for h > -1/9 there exists a self-similar equilibrium point provided that gamma is an element of (2(3+root-h)/5+3 root-h, 3/2) whereas for h < -1/9 the state parameter belongs to the interval gamma is an element of (1, 2(3+root-h)/5+3 root-h). This family of new exact self-similar solutions belongs to the subclass n(alpha)(alpha) = 0 having non-zero vorticity. In both cases the equilibrium points have a six-dimensional stable manifold and may act as future attractors at least for the models satisfying n(alpha)(alpha) = 0. Also we give the exact form of the self-similar metrics in terms of the state and group parameter. As an illustrative example we provide the explicit form of the corresponding self-similar radiation model (gamma = 4/3), parametrised by the group parameter h. Finally we show that there are no tilted self-similar models of type III and irrotational models of type VIh

Self-similar Bianchi models: II. Class B models

In a companion article (referred to hereafter as paper I) a detailed study of the simply transitive spatially homogeneous (SH) models of class A concerning the existence of a simply transitive similarity group has been given. The present work (paper II) continues and completes the above study by considering the remaining set of class B models. Following the procedure of paper I we find all SH models of class B subjected only to the minimal geometric assumption to admit a proper homothetic vector field (HVF). The physical implications of the obtained geometric results are studied by specializing our considerations to the case of vacuum and gamma-law perfect fluid models. As a result, we regain all the known exact solutions regarding vacuum and non-tilted perfect fluid models. In the case of tilted fluids, we find the general self-similar solution for the exceptional type VI-(1/9) model and we identify it as an equilibrium point in the corresponding dynamical state space. It is found that this new, exact solution belongs to the subclass of models n(alpha)(alpha) = 0, is defined for gamma is an element of ((4)/(3), (3)/(2) ), and although it has a five-dimensional stable manifold there always exist two unstable modes in the restricted state space. Furthermore, the analysis of the remaining types guarantees that tilted perfect fluid models of types III, IV, V and VIIh cannot admit a proper HVF, strongly suggesting that these models either may not be asymptotically self-similar (type V) or may be extreme tilted at late times. Finally, for each Bianchi type, we give the extreme tilted equilibrium points of their state space

Comment on Ricci collineations for type B warped space-times

We present two counter examples to paper [2] by Carot et al. and show that the results obtained are correct but not general

Brane cosmological evolution with a general bulk matter configuration

Using a fully covariant treatment for the description of the bulk geometry, we study the brane cosmological evolution in the presence of a smooth bulk matter distribution. We focus on the case of a Friedmann-Robertson-Walker brane, invariantly characterized by the existence of a six-dimensional group of isometries acting on 3D spacelike orbits. With a Friedmann-Robertson-Walker brane, the bulk geometry can be regarded as the 5D generalization of the inhomogeneous orthogonal family of locally rotationally symmetric spacetimes. We show that, for any bulk matter configuration, the expansion rate on the brane depends only on the covariantly defined comoving mass M of the bulk fluid within a radius equal to the average length scale of the 3D spacelike hypersurfaces of constant curvature. This unique contribution incorporates the effects of the 5D Weyl tensor and the projected tensor related to the bulk matter, and gives a transparent physical picture that includes an effective conservation equation between the brane and the bulk matter

Conformal symmetries in warped manifolds

The existence of a Conformal Vector Field (CVF) is studied in the important class of warped manifolds of arbitrary dimension generalizing in this way the corresponding results of the four dimensional geometries. As a concrete example we apply the geometric results in the case of brane-world scenarios when the bulk geometry admits a hypersurface orthogonal Killing Vector Field (KVF) and is filled with a perfect fluid matter content