187 research outputs found
Statistical Effects and the Black Hole/D-brane Correspondence
The horizon area and curvature of three-charge BPS black strings are studied
in the D-brane ensemble for the stationary black string. The charge
distributions along the string are used to translate the classical expressions
for the horizon area and curvature of BPS black strings with waves into
operators on the D-brane Hilbert space. Despite the fact that any `wavy' black
string has smaller horizon area and divergent curvature, the typical values of
the horizon area and effects of the horizon curvature in the D-brane ensemble
deviate negligibly from those of the original stationary black string in the
limit of large integer charges. Whether this holds in general will depend on
certain properties of the quantum bound states.Comment: 13 pages, RevTex, small errors corrected, some interpretation changed
in light of new result
Localized Branes and Black Holes
We address the delocalization of low dimensional D-branes and NS-branes when
they are a part of a higher dimensional BPS black brane, and the homogeneity of
the resulting horizon. We show that the effective delocalization of such branes
is a classical effect that occurs when localized branes are brought together.
Thus, the fact that the few known solutions with inhomogeneous horizons are
highly singular need not indicate a singularity of generic D- and NS-brane
states. Rather, these singular solutions are likely to be unphysical as they
cannot be constructed from localized branes which are brought together from a
finite separation.Comment: 13 pages, RevTex, no figures, few references and comments adde
RELEASE (REdressing Long-tErm Antidepressant uSE): protocol for a 3-arm pragmatic cluster randomised controlled trial effectiveness-implementation hybrid type-1 in general practice
BACKGROUND: Many people experience withdrawal symptoms when they attempt to stop antidepressants. Withdrawal symptoms are readily misconstrued for relapse or ongoing need for medication, contributing to long-term use (>â12Â months). Long-term antidepressant use is increasing internationally yet is not recommended for most people. Long-term use is associated with adverse effects including weight gain, sexual dysfunction, lethargy, emotional numbing and increased risk of falls and fractures. This study aims to determine the effectiveness of two multi-strategy interventions (RELEASE and RELEASE+) in supporting the safe cessation of long-term antidepressants, estimate cost-effectiveness, and evaluate implementation strategies. METHODS: DESIGN: 3-arm pragmatic cluster randomised controlled trial effectiveness-implementation hybrid type-1. SETTING: primary care general practices in southeast Queensland, Australia. POPULATION: adults 18Â years or older taking antidepressants for longer than 1Â year. Practices will be randomised on a 1.5:1:1 ratio of Usual care:RELEASE:RELEASE+. INTERVENTION: RELEASE for patients includes evidence-based information and resources and an invitation to medication review; RELEASE for GPs includes education, training and printable resources via practice management software. RELEASE+ includes additional internet support for patients and prescribing support including audit and feedback for GPs. OUTCOME MEASURES: the primary outcome is antidepressant use at 12Â months self-reported by patients. Cessation is defined as 0Â mg antidepressant maintained for at least 2Â weeks. SECONDARY OUTCOMES: at 6 and 12Â months are health-related quality of life, antidepressant side effects, well-being, withdrawal symptoms, emotional numbing, beliefs about antidepressants, depressive symptoms, and anxiety symptoms; and at 12Â months 75% reduction in antidepressant dose; aggregated practice level antidepressant prescribing, and health service utilisation for costs. SAMPLE SIZE: 653 patients from 28 practices. A concurrent evaluation of implementation will be through mixed methods including interviews with up to 40 patients and primary care general practitioners, brief e-surveys, and study administrative data to assess implementation outcomes (adoption and fidelity). DISCUSSION: The RELEASE study will develop new knowledge applicable internationally on the effectiveness, cost-effectiveness, and implementation of two multi-strategy interventions in supporting the safe cessation of long-term antidepressants to improve primary health care and outcomes for patients. TRIAL REGISTRATION: ANZCTR, ACTRN12622001379707p. Registered on 27 October 2022
The patterns of ethnic settlement and violence: a local-level quantitative analysis of the Bosnian War
Brane Baldness vs. Superselection Sectors
The search for intersecting brane solutions in supergravity is a large and
profitable industry. Recently, attention has focused on finding localized forms
of known `delocalized' solutions. However, in some cases, a localized version
of the delocalized solution simply does not exist. Instead, localized separated
branes necessarily delocalize as the separation is removed. This phenomenon is
related to black hole no-hair theorems, i.e. `baldness.' We continue the
discussion of this effect and describe how it can be understood, in the case of
Dirichlet branes, in terms of the corresponding intersection field theory. When
it occurs, it is associated with the quantum mixing of phases and lack of
superselection sectors in low dimensional field theories. We find surprisingly
wide agreement between the field theory and supergravity both with respect to
which examples delocalize and with respect to the rate at which this occurs.Comment: 26 pages, ReVTeX, 2 figures, reference added, version to appear in
PR
Single-exterior black holes and the AdS-CFT conjecture
In the context of the conjectured AdS-CFT correspondence of string theory, we
consider a class of asymptotically Anti-de Sitter black holes whose conformal
boundary consists of a single connected component, identical to the conformal
boundary of Anti-de Sitter space. In a simplified model of the boundary theory,
we find that the boundary state to which the black hole corresponds is pure,
but this state involves correlations that produce thermal expectation values at
the usual Hawking temperature for suitably restricted classes of operators. The
energy of the state is finite and agrees in the semiclassical limit with the
black hole mass. We discuss the relationship between the black hole topology
and the correlations in the boundary state, and speculate on generalizations of
the results beyond the simplified model theory.Comment: 27 pages, LaTeX, using REVTeX v3.1 with amsfonts and epsf, with two
eps figures. (v3: references updated
Geons with spin and charge
We construct new geon-type black holes in D>3 dimensions for Einstein's
theory coupled to gauge fields. A static nondegenerate vacuum black hole has a
geon quotient provided the spatial section admits a suitable discrete isometry,
and an antisymmetric tensor field of rank 2 or D-2 with a pure F^2 action can
be included by an appropriate (and in most cases nontrivial) choice of the
field strength bundle. We find rotating geons as quotients of the
Myers-Perry(-AdS) solution when D is odd and not equal to 7. For other D we
show that such rotating geons, if they exist at all, cannot be continuously
deformed to zero angular momentum. With a negative cosmological constant, we
construct geons with angular momenta on a torus at the infinity. As an example
of a nonabelian gauge field, we show that the D=4 spherically symmetric SU(2)
black hole admits a geon version with a trivial gauge bundle. Various
generalisations, including both black-brane geons and Yang-Mills theories with
Chern-Simons terms, are briefly discussed.Comment: 26 pages, 1 figure. LaTeX with amssymb, amsmath. (v2: References and
a figure added.
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