Near Horizon Extremal Geometry Perturbations: Dynamical Field Perturbations vs. Parametric Variations

In arXiv:1310.3727 we formulated and derived the three universal laws governing Near Horizon Extremal Geometries (NHEG). In this work we focus on the Entropy Perturbation Law (EPL) which, similarly to the first law of black hole thermodynamics, relates perturbations of the charges labeling perturbations around a given NHEG to the corresponding entropy perturbation. We show that field perturbations governed by the linearized equations of motion and symmetry conditions which we carefully specify, satisfy the EPL. We also show that these perturbations are limited to those coming from difference of two NHEG solutions (i.e. variations on the NHEG solution parameter space). Our analysis and discussions shed light on the "no-dynamics" statements of arXiv:0906.2380 and arXiv:0906.2376.Comment: 38 page

Solution Phase Space and Conserved Charges: A General Formulation for Charges Associated with Exact Symmetries

We provide a general formulation for calculating conserved charges for solutions to generally covariant gravitational theories with possibly other internal gauge symmetries, in any dimensions and with generic asymptotic behaviors. These solutions are generically specified by a number of exact (continuous, global) symmetries and some parameters. We define "parametric variations" as field perturbations generated by variations of the solution parameters. Employing the covariant phase space method, we establish that the set of these solutions (up to pure gauge transformations) form a phase space, the \emph{solution phase space}, and that the tangent space of this phase space includes the parametric variations. We then compute conserved charge variations associated with the exact symmetries of the family of solutions, caused by parametric variations. Integrating the charge variations over a path in the solution phase space, we define the conserved charges. In particular, we revisit "black hole entropy as a conserved charge" and the derivation of the first law of black hole thermodynamics. We show that the solution phase space setting enables us to define black hole entropy by an integration over any compact, codminesion-2, smooth spacelike surface encircling the hole, as well as to a natural generalization of Wald and Iyer-Wald analysis to cases involving gauge fields.Comment: 35 pp, no figure

Wiggling Throat of Extremal Black Holes

We construct the classical phase space of geometries in the near-horizon region of vacuum extremal black holes as announced in [arXiv:1503.07861]. Motivated by the uniqueness theorems for such solutions and for perturbations around them, we build a family of metrics depending upon a single periodic function defined on the torus spanned by the $U(1)$ isometry directions. We show that this set of metrics is equipped with a consistent symplectic structure and hence defines a phase space. The phase space forms a representation of an infinite dimensional algebra of so-called symplectic symmetries. The symmetry algebra is an extension of the Virasoro algebra whose central extension is the black hole entropy. We motivate the choice of diffeomorphisms leading to the phase space and explicitly derive the symplectic structure, the algebra of symplectic symmetries and the corresponding conserved charges. We also discuss a formulation of these charges with a Liouville type stress-tensor on the torus defined by the $U(1)$ isometries and outline possible future directions.Comment: 56 pages, 3 figure

The association of fasting blood glucose (FBG) and waist circumference in northern adults in Iran: A population based study

Objectives: The aim of this study was to evaluate the association between Fasting Blood Glucose (FBG) level and Waist Circumference (WC) in men and women among 25-65 years old people in the north of Iran.Material and methods: This was a cross-sectional and analytical research gender that carried out on the 1797 subjects (941 males and 856 females) between 25-65 years old using multistage cluster sampling technique. FBG was measured in the morning after a 12-hour fast and was determined by using laboratory kits (enzymatic methods) and spectrophotometry technique. Central obesity was defined based on World Health Organization criteria: waist circumference ≥102 cm and ≥88 cm in men and women, respectively. The SPSS.16 software was used for statistical analysis.Results: As whole, the mean of FBG in women (98.3 ± 40.1 mg/dl) was higher than in men (94.6 ± 32.2 mg/dl). Also, the mean of WC in men 4.5 cm was lower than in women. In men, the mean of FBG statistically differs between normal and central obese subjects both in 35-45 year-age group (P = 0.001) and in 45-55 year-age group (P = 0.042). As whole, in men, the FBG level increased up 2.82 mg/dl in each 10 cm of WC with the highest rate in 35-45 year-age group. In totally, in women, the FBG level increased up 3.48 mg/dl in each 10 cm of WC and in 25-35 year-age group and it was higher than in other age groups. In men, the regression coefficients were constant with age increasing while in women it was decreased. Constant trend in men and decreasing trend in women with age was shown between FBG and WC. The cut-off point of WC for detecting of diabetes obtained 89 cm and 107 cm in men and women, respectively.Conclusion: The positive correlation was seen between WC and FBG level and it was declined with age in women. Cut-off point for detecting of diabetes in men was less than in women. WC is useable as a predictor of type 2 diabetes mellitus risk among adults in the north of Iran. © 2014 Veghari et al.; licensee BioMed Central Ltd

A suggested prototype for assessing bone health

Background- Osteoporosis is becoming a health concern worldwide. Considering the fact that prevention plays an important role in reducing the burden of this silent disease and in view of the limited resources available, many countries have adopted certain programs to fight osteoporosis through shifting their attention towards at-risk individuals. The Iranian Multicenter Osteoporosis Study (IMOS) is one of these programs. The program aims to assess bone health and the prevalence of vitamin D deficiency in different parts of Iran with various altitudes, latitudes and lifestyle habits in a way that the results could be generalized to the country. Method- The present article presents the protocol used in the third phase of the study. It was designed based on the experiences gathered in the previous phases to overcome the shortcomings particularly subject loss. The questionnaire applied in this study was developed based on a thorough literature review of the risk factors and secondary causes of osteoporosis and was approved by an expert panel. It should be added that while the majority of the existing studies aim to study a certain aspect of osteoporosis, the present protocol provides the information needed for policy makers and researchers to study different osteoporosis-related issues. Conclusion- The authors believe the protocol, to be implemented with small modifications, can help policymakers in different parts of the world, particularly developing countries, gather accurate information on different aspects of bone health at the national level. © 2015, Academy of Medical Sciences of I.R. Iran. All rights reserved

Anisotropic Inflation from Charged Scalar Fields

We consider models of inflation with U(1) gauge fields and charged scalar fields including symmetry breaking potential, chaotic inflation and hybrid inflation. We show that there exist attractor solutions where the anisotropies produced during inflation becomes comparable to the slow-roll parameters. In the models where the inflaton field is a charged scalar field the gauge field becomes highly oscillatory at the end of inflation ending inflation quickly. Furthermore, in charged hybrid inflation the onset of waterfall phase transition at the end of inflation is affected significantly by the evolution of the background gauge field. Rapid oscillations of the gauge field and its coupling to inflaton can have interesting effects on preheating and non-Gaussianities.Comment: minor changes, references added, figures are modified, conforms JCAP published versio

The Discovery of Infrared Rings in the Planetary Nebula NGC 1514 During the WISE All-Sky Survey

We report the discovery of a pair of infrared, axisymmetric rings in the planetary nebula NGC 1514 during the course of the WISE all-sky mid-infrared survey. Similar structures are seen at visible wavelengths in objects such as the "Engraved Hourglass Nebula" (MyCn 18) and the "Southern Crab Nebula" (Hen 2-104). However, in NGC 1514 we see only a single pair of rings and they are easily observed only in the mid-infrared. These rings are roughly 0.2 pc in diameter, are separated by 0.05 pc, and are dominated by dust emission with a characteristic temperature of 160 K. We compare the morphology and color of the rings to the other nebular structures seen at visible, far-infrared, and radio wavelengths, and close with a discussion of a physical model and formation scenario for NGC 1514.Comment: 16 pages, 10 figures, final version published in 2010 December Astronomical Journa

CMB constraints on noncommutative geometry during inflation

We investigate the primordial power spectrum of the density perturbations based on the assumption that spacetime is noncommutative in the early stage of inflation. Due to the spacetime noncommutativity, the primordial power spectrum can lose rotational invariance. Using the k-inflation model and slow-roll approximation, we show that the deviation from rotational invariance of the primordial power spectrum depends on the size of noncommutative length scale L_s but not on sound speed. We constrain the contributions from the spacetime noncommutativity to the covariance matrix for the harmonic coefficients of the CMB anisotropies using five-year WMAP CMB maps. We find that the upper bound for L_s depends on the product of sound speed and slow-roll parameter. Estimating this product using cosmological parameters from the five-year WMAP results, the upper bound for L_s is estimated to be less than 10^{-27} cm at 99.7% confidence level.Comment: 8 pages, 1 figure, References added, Accepted for publication in EPJC (submitted version

Primordial statistical anisotropy generated at the end of inflation

We present a new mechanism for generating primordial statistical anisotropy of curvature perturbations. We introduce a vector field which has a non-minimal kinetic term and couples with a waterfall field in hybrid inflation model. In such a system, the vector field gives fluctuations of the end of inflation and hence induces a subcomponent of curvature perturbations. Since the vector has a preferred direction, the statistical anisotropy could appear in the fluctuations. We present the explicit formula for the statistical anisotropy in the primordial power spectrum and the bispectrum of curvature perturbations. Interestingly, there is the possibility that the statistical anisotropy does not appear in the power spectrum but does appear in the bispectrum. We also find that the statistical anisotropy provides the shape dependence to the bispectrum.Comment: 9 pages, This version supersedes the JCAP version. Minor revision