130 research outputs found

    Hairy black holes in theories with massive gravitons

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    This is a brief survey of the known black hole solutions in the theories of ghost-free bigravity and massive gravity. Various black holes exist in these theories, in particular those supporting a massive graviton hair. However, it seems that solutions which could be astrophysically relevant are the same as in General Relativity, or very close to them. Therefore, the no-hair conjecture essentially applies, and so it would be hard to detect the graviton mass by observing black holes.Comment: References added. 20 pages, 3 figures, based on the talk given at the 7-th Aegean Summer School "Beyond Einstein's theory of gravity", September 201

    On Black Hole Scalar Hair in Asymptotically Anti de Sitter Spacetimes

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    The unexpected discovery of hairy black hole solutions in theories with scalar fields simply by considering asymptotically Anti de-Sitter, rather than asymptotically flat, boundary conditions is analyzed in a way that exhibits in a clear manner the differences between the two situations. It is shown that the trivial Schwarzschild Anti de Sitter becomes unstable in some of these situations, and the possible relevance of this fact for the ADS/CFT conjecture is pointed out.Comment: 12 pages. Published versio

    Exile Vol. XVI No. 1

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    DRAMA God\u27s Pocket by Robert R. Bowie, Jr. 5-12 FICTION The Wagon by John Anderson 18-19 An Infinity of Mirrors by Keith McWalter 23-25 Commitment by John Whitt 28-29 It began not long ago... by Linda Notzelman 32-33 Jaundiced Evening by John Benes 35-39 POETRY Paralysis Outline by Lauren Shakely 13 A Woman Reads Camus by Lauren Shakely 14 don\u27t sell my rings by Lauren Shakely 14 Drift by John Whitt 17 Haiku by M. S. Wallace 19 To Begin W. K. Mayo 19 Dark is Right by Louise Tate 20 I am waiting by Louise Tate 21 My mother died as I shall die by Tim Cope 20 I never blamed you by Tim Cope 26 For Miss Didawick by Tim Cope 34 Separidian by Bill Whitmore 27 He walks on into by Whitney Carman 31 As Drowned Men Rise by Paul Bennett 34 The Tolling of the Bell by Keith McWalter 39 ARTWORK by Wandi Solez 4, 13, 16, 22, 36 by W. A. Hoffman 21, 30 by Stephen Sneeringer 27 by Christine Michael 19 Cover & Title Page Design: Keith McWalter Layouts: Keith McWalter Publicity- Special thanks to Gail Moore and Karen Baker Photographs courtesy the Sierra Club- From NOT MAN APART, Copyright 196

    Scalar hairy black holes and solitons in asymptotically flat spacetimes

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    A numerical analysis shows that a class of scalar-tensor theories of gravity with a scalar field minimally and nonminimally coupled to the curvature allows static and spherically symmetric black hole solutions with scalar-field hair in asymptotically flat spacetimes. In the limit when the horizon radius of the black hole tends to zero, regular scalar solitons are found. The asymptotically flat solutions are obtained provided that the scalar potential V(Ď•)V(\phi) of the theory is not positive semidefinite and such that its local minimum is also a zero of the potential, the scalar field settling asymptotically at that minimum. The configurations for the minimal coupling case, although unstable under spherically symmetric linear perturbations, are regular and thus can serve as counterexamples to the no-scalar-hair conjecture. For the nonminimal coupling case, the stability will be analyzed in a forthcoming paper.Comment: 7 pages, 10 postscript figures, file tex, new postscript figs. and references added, stability analysis revisite

    No hair for spherical black holes: charged and nonminimally coupled scalar field with self--interaction

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    We prove three theorems in general relativity which rule out classical scalar hair of static, spherically symmetric, possibly electrically charged black holes. We first generalize Bekenstein's no--hair theorem for a multiplet of minimally coupled real scalar fields with not necessarily quadratic action to the case of a charged black hole. We then use a conformal map of the geometry to convert the problem of a charged (or neutral) black hole with hair in the form of a neutral self--interacting scalar field nonminimally coupled to gravity to the preceding problem, thus establishing a no--hair theorem for the cases with nonminimal coupling parameter ξ<0\xi<0 or ξ≥12\xi\geq {1\over 2}. The proof also makes use of a causality requirement on the field configuration. Finally, from the required behavior of the fields at the horizon and infinity we exclude hair of a charged black hole in the form of a charged self--interacting scalar field nonminimally coupled to gravity for any ξ\xi.Comment: 30 pages, RevTeX. Sec.IV corrected, simplified and shortened. Corrections to Sec.IIA between Eqs. 2.7 and Eq.2.1. First two paragraphs of Sec. VC new. To appear Phys. Rev. D, Oct. 15, 199

    Violence perpetration and childhood abuse among men and women in substance abuse treatment

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    Abstract Despite an association between violence perpetration and substance use, the characteristics associated with violence among patients in treatment for substance use disorders (SUDs) are not well documented. Data were gathered from a national sample of men (n = 4,459) and women (n = 1,774) entering SUD treatment on history of violence perpetration, exposure to childhood physical abuse (CPA) and childhood sexual abuse (CSA), and reasons for entering treatment. Rates of violence perpetration were high (72% of men, 50% of women), and violence was associated with being referred by family members, prior SUD treatment, CPA, and CSA. In multivariate analyses, CPA was a significant correlate of violence perpetration across gender; however, CSA was only significant among women. Findings highlight the need for increased screening and treatment of violence perpetration among patients with SUD and suggest that CSA may be an important correlate of violence perpetration among women. Published by Elsevier Inc

    Observing Supermassive Black Holes across cosmic time: from phenomenology to physics

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    In the last decade, a combination of high sensitivity, high spatial resolution observations and of coordinated multi-wavelength surveys has revolutionized our view of extra-galactic black hole (BH) astrophysics. We now know that supermassive black holes reside in the nuclei of almost every galaxy, grow over cosmological times by accreting matter, interact and merge with each other, and in the process liberate enormous amounts of energy that influence dramatically the evolution of the surrounding gas and stars, providing a powerful self-regulatory mechanism for galaxy formation. The different energetic phenomena associated to growing black holes and Active Galactic Nuclei (AGN), their cosmological evolution and the observational techniques used to unveil them, are the subject of this chapter. In particular, I will focus my attention on the connection between the theory of high-energy astrophysical processes giving rise to the observed emission in AGN, the observable imprints they leave at different wavelengths, and the methods used to uncover them in a statistically robust way. I will show how such a combined effort of theorists and observers have led us to unveil most of the SMBH growth over a large fraction of the age of the Universe, but that nagging uncertainties remain, preventing us from fully understating the exact role of black holes in the complex process of galaxy and large-scale structure formation, assembly and evolution.Comment: 46 pages, 21 figures. This review article appears as a chapter in the book: "Astrophysical Black Holes", Haardt, F., Gorini, V., Moschella, U and Treves A. (Eds), 2015, Springer International Publishing AG, Cha

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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