655 research outputs found
Supergravity at the boundary of AdS supergravity
We give a general analysis of AdS boundary conditions for spin-3/2
Rarita-Schwinger fields and investigate boundary conditions preserving
supersymmetry for a graviton multiplet in AdS_4. Linear Rarita-Schwinger fields
in AdS_d are shown to admit mixed Dirichlet-Neumann boundary conditions when
their mass is in the range . We also demonstrate that
mixed boundary conditions are allowed for larger masses when the inner product
is "renormalized" accordingly with the action. We then use the results obtained
for |m| = 1/l_{AdS} to explore supersymmetric boundary conditions for N = 1
AdS_4 supergravity in which the metric and Rarita-Schwinger fields are
fluctuating at the boundary. We classify boundary conditions that preserve
boundary supersymmetry or superconformal symmetry. Under the AdS/CFT
dictionary, Neumann boundary conditions in d=4 supergravity correspond to
gauging the superconformal group of the 3-dimensional CFT describing M2-branes,
while N = 1 supersymmetric mixed boundary conditions couple the CFT to N = 1
superconformal topologically massive gravity.Comment: 23 pages, RevTe
A note on Kerr/CFT and free fields
The near-horizon geometry of the extremal four-dimensional Kerr black hole
and certain generalizations thereof has an SL(2,R) x U(1) isometry group.
Excitations around this geometry can be controlled by imposing appropriate
boundary conditions. For certain boundary conditions, the U(1) isometry is
enhanced to a Virasoro algebra. Here, we propose a free-field construction of
this Virasoro algebra.Comment: 10 pages, v2: comments and references adde
Advanced simulation code for alpha spectrometry
A Monte Carlo code, known as AASI, is developed for simulating energy spectra
in alpha spectrometry. The code documented here is a comprehensive package
where all the major processes affecting the spectrum are included. A unique
feature of the code is its ability to take into account coincidences between
the particles emitted from the source. Simulations and measurements highlight
the importance of coincidences in high-resolution alpha spectrometry. To show
the validity of the simulated results, comparisons with measurements and other
simulation codes are presented.Comment: 21 pages, 4 figures, to be published in Nucl. Instr. and Meth.
From Unruh temperature to generalized Bousso bound
In a classical spacetime satisfying Einstein's equation and the null
convergence condition, the same quantum mechanical effects that cause black
holes to have a temperature are found to imply, if joined to the macroscopic
nature of entropy, the covariant entropy bound in its generalized form. This is
obtained from thermodynamics, as applied across the local Rindler causal
horizon through every point p of the null hypersurfaces L the covariant entropy
bound refers to, in the direction of the null geodesics generating L.Comment: 5 pages. v2: some changes to clarify the path to the obtained
results; two (final) paragraphs, the acknowledgments and a reference adde
How to Identify Exposed Women Who Are Infected with Neisseria gonorrhoeae.
Treatment trials of antibiotics for Neisseria gonorrhoeae infections frequently enroll primarily men with urethritis, as the diagnosis of acute gonococcal infection in men with urethritis is easily made by Gram stain of the urethral exudate, followed by confirmatory culture or nucleic acid amplification tests (NAATs). Enrolling women in treatment trials is of great importance, but N. gonorrhoeae cervical infections cause nonspecific symptoms. This makes it difficult to conduct interventional trials, as large numbers of women with nonspecific symptoms need to be screened for infection. Gram stain of cervical secretions has a strikingly low sensitivity, and culture and/or NAAT results are not available at the time of screening. This necessitates recall and delayed treatment of infected women who may not return and who may spread the infection during the interval. In this chapter we present an algorithm, derived from a comparison of women who did, or did not, become infected during exposure, which identifies those women who are highly likely to be infected before culture and/or NAAT results are available. The algorithm provides an efficient way to conduct interventional trials in women without the problem of recall and delayed treatment
Stability in Designer Gravity
We study the stability of designer gravity theories, in which one considers
gravity coupled to a tachyonic scalar with anti-de Sitter boundary conditions
defined by a smooth function W. We construct Hamiltonian generators of the
asymptotic symmetries using the covariant phase space method of Wald et al.and
find they differ from the spinor charges except when W=0. The positivity of the
spinor charge is used to establish a lower bound on the conserved energy of any
solution that satisfies boundary conditions for which has a global minimum.
A large class of designer gravity theories therefore have a stable ground
state, which the AdS/CFT correspondence indicates should be the lowest energy
soliton. We make progress towards proving this, by showing that minimum energy
solutions are static. The generalization of our results to designer gravity
theories in higher dimensions involving several tachyonic scalars is discussed.Comment: 29 page
Investigating Canadian parents' HPV vaccine knowledge, attitudes and behaviour: a study protocol for a longitudinal national online survey
Introduction
Human papillomavirus (HPV), a sexually transmitted infection, can cause anogenital warts and a number of cancers. To prevent morbidity and mortality, three vaccines have been licensed and are recommended by Canada’s National Advisory Committee on Immunisation (for girls since 2007 and boys since 2012). Nevertheless, HPV vaccine coverage in Canada remains suboptimal in many regions. This study will be the first to concurrently examine the correlates of HPV vaccine decision-making in parents of school-aged girls and boys and evaluate changes in parental knowledge, attitudes and behaviours over time.
Methods and analysis
Using a national, online survey utilising theoretically driven constructs and validated measures, this study will identify HPV vaccine coverage rates and correlates of vaccine decision-making in Canada at two time points (August–September 2016 and June–July 2017). 4606 participants will be recruited to participate in an online survey through a market research and polling firm using email invitations. Data cleaning methods will identify inattentive or unmotivated participants.
Ethics and dissemination
The study received research ethics board approval from the Research Review Office, Integrated Health and Social Services University Network for West-Central Montreal (CODIM-FLP-16–219). The study will adopt a multimodal approach to disseminate the study’s findings to researchers, clinicians, cancer and immunisation organisations and the public in Canada and internationally
Uniqueness Theorem for Black Hole Space-Times with Multiple Disconnected Horizons
We show uniqueness of stationary and asymptotically flat black hole
space-times with multiple disconnected horizons and with two rotational Killing
vector fields in the context of five-dimensional minimal supergravity
(Einstein-Maxwell-Chern-Simons gravity). The novelty in this work is the
introduction in the uniqueness theorem of intrinsic local charges measured near
each horizon as well as the measurement of local fluxes besides the asymptotic
charges that characterize a particular solution. A systematic method of
defining the boundary conditions on the fields that specify a black hole
space-time is given based on the study of its rod structure (domain structure).
Also, an analysis of known solutions with disconnected horizons is carried out
as an example of an application of this theorem.Comment: 28 pages, 5 figures. v3: Further improvements on uniqueness theorem,
Lemma introduced for clarity of derivation, new quantities introduced to
treat special case with zero flux, refs. added, typos fixe
Clubbing masculinities: Gender shifts in gay men's dance floor choreographies
This is an Author's Accepted Manuscript of an article published in Journal of Homosexuality, 58(5), 608-625, 2011 [copyright
Taylor & Francis], available online at: http://www.tandfonline.com/10.1080/00918369.2011.563660This article adopts an interdisciplinary approach to understanding the intersections of gender, sexuality, and dance. It examines the expressions of sexuality among gay males through culturally popular forms of club dancing. Drawing on political and musical history, I outline an account of how gay men's gendered choreographies changed throughout the 1970s, 80s, and 90s. Through a notion of “technologies of the body,” I situate these developments in relation to cultural levels of homophobia, exploring how masculine expressions are entangled with and regulated by musical structures. My driving hypothesis is that as perceptions of cultural homophobia decrease, popular choreographies of gay men's dance have become more feminine in expression. Exploring this idea in the context of the first decade of the new millennium, I present a case study of TigerHeat, one of the largest weekly gay dance club events in the United States
Holography at an Extremal De Sitter Horizon
Rotating maximal black holes in four-dimensional de Sitter space, for which
the outer event horizon coincides with the cosmological horizon, have an
infinite near-horizon region described by the rotating Nariai metric. We show
that the asymptotic symmetry group at the spacelike future boundary of the
near-horizon region contains a Virasoro algebra with a real, positive central
charge. This is evidence that quantum gravity in a rotating Nariai background
is dual to a two-dimensional Euclidean conformal field theory. These results
are related to the Kerr/CFT correspondence for extremal black holes, but have
two key differences: one of the black hole event horizons has been traded for
the cosmological horizon, and the near-horizon geometry is a fiber over dS_2
rather than AdS_2.Comment: 15 page
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