392 research outputs found
Graviton confinement inside hypermonopoles of any dimension
We show the generic existence of metastable massive gravitons in the
four-dimensional core of self-gravitating hypermonopoles in any number of
infinite-volume extra-dimensions. Confinement is observed for Higgs and gauge
bosons couplings of the order unity. Provided these resonances are light
enough, they realise the Dvali-Gabadadze-Porrati mechanism by inducing a
four-dimensional gravity law on some intermediate length scales. The effective
four-dimensional Planck mass is shown to be proportional to a negative power of
the graviton mass. As a result, requiring gravity to be four-dimensional on
cosmological length scales may solve the mass hierarchy problem.Comment: 23 pages, 6 figures, uses iopart. Misprints corrected, references
added, matches published versio
Inseminação artificial com sêmen resfriado em eqüinos - efeito da adição de antibióticos ao diluente na fertilidade de éguas susceptíveis e resistentes à endometrite e nas características espermáticas
On brane-induced gravity in warped backgrounds
We study whether modification of gravity at large distances is possible in
warped backgrounds with two branes and a brane-induced term localized on one of
the branes. We find that there are three large regions in the parameter space
where the theory is weakly coupled up to high energies. In one of these regions
gravity on the brane is four-dimensional at arbitrarily large distances, and
the induced Einstein term results merely in the renormalization of the 4d
Planck mass. In the other two regions the behavior of gravity changes at
ultra-large distances; however, radion becomes a ghost. In parts of these
regions, both branes have positive tensions, so the only reason for the
appearance of the ghost field is the brane-induced term. In between these three
regions, there are domains in the parameter space where gravity is strongly
coupled at phenomenologically unacceptable low energy scale.Comment: 12 pages, 2 fig, JHEP3 style required, typos correcte
Holographic Domains of Anti-de Sitter Space
An AdS_4 brane embedded in AdS_5 exhibits the novel feature that a
four-dimensional graviton is localized near the brane, but the majority of the
infinite bulk away from the brane where the warp factor diverges does not see
four-dimensional gravity. A naive application of the holographic principle from
the point of view of the four-dimensional observer would lead to a paradox; a
global holographic mapping would require infinite entropy density. In this
paper, we show that this paradox is resolved by the proper covariant
formulation of the holographic principle. This is the first explicit example of
a time-independent metric for which the spacelike formulation of the
holographic principle is manifestly inadequate. Further confirmation of the
correctness of this approach is that light-rays leaving the brane intersect at
the location where we expect four-dimensional gravity to no longer dominate. We
also present a simple method of locating CFT excitations dual to a particle in
the bulk. We find that the holographic image on the brane moves off to infinity
precisely when the particle exits the brane's holographic domain. Our analysis
yields an improved understanding of the physics of the AdS_4/AdS_5 model.Comment: 29 pages, 6 figure
DXA-derived hip shape is related to osteoarthritis:findings from in the MrOS cohort
BF conducted this research whilst on a clinical research primer fellowship awarded by the Elizabeth Blackwell Institute, University of Bristol, UK. This study was funded by Arthritis Research UK project grant ref 20244. CG is funded by Arthritis Research UK grant ref 20000. The Osteoporotic Fractures in Men (MrOS) Study is supported by National Institutes of Health funding. The following institutes provide support: the National Institute on Aging (NIA), the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Center for Advancing Translational Sciences (NCATS), and NIH Roadmap for Medical Research under the following grant numbers: R01 AR052000, K24 AR048841, U01 AG027810, U01 AG042124, U01 AG042139, U01 AG042140, U01 AG042143, U01 AG042145, U01 AG042168, U01 AR066160, and UL1 TR000128.Peer reviewedPostprin
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