119 research outputs found
Reissner-Nordstrom-de Sitter black hole, planar coordinates and dS/CFT
We discuss the Reissner-Nordstrom-de Sitter black holes in the context of
dS/CFT correspondence by using static and planar coordinates. The boundary
stress tensor and the mass of the solutions are computed. Also, we investigate
how the RG flow is changed for different foliations. The Kastor-Traschen
multi-black hole solution is considered as well as AdS counterparts of these
configurations. In particular, we find that in planar coordinates the black
holes appear like punctures in the dual boundary theory.Comment: 30 pages, 3 eps figures, JHEP style v2: new references added,
misprints correcte
Nutty Bubbles
We investigate the various time-dependent bubble spacetimes that can be
obtained from double analytic continuation of asymptotically locally flat/AdS
spacetimes with NUT charge. We find different time-dependent explicit solutions
of general relativity from double analytic continuations of Taub-Nut(-AdS) and
Kerr-Nut(-AdS) spacetimes. One solution in particular has Milne-like evolution
throughout, and another is a NUT-charged generalization of the AdS soliton.
These solutions are all four dimensional. In certain situations the NUT charge
induces an ergoregion into the bubble spacetime and in other situations it
quantitatively modifies the evolution of the bubble, as when rotation is
present. In dimensions greater than four, no consistent bubble solutions are
found that have only one timelike direction.Comment: 29 pages, 10 figure
Scale Vs. Conformal Invariance in the AdS/CFT Correspondence
We present two examples of non-trivial field theories which are scale
invariant, but not conformally invariant. This is done by placing certain field
theories, which are conformally invariant in flat space, onto curved
backgrounds of a specific type. We define this using the AdS/CFT
correspondence, which relates the physics of gravity in asymptotically Anti-de
Sitter (AdS) spacetimes to that of a conformal field theory (CFT) in one
dimension fewer. The AdS rotating (Kerr) black holes in five and seven
dimensions provide us with the examples, since by the correspondence we are
able to define and compute the action and stress tensor of four and six
dimensional field theories residing on rotating Einstein universes, using the
``boundary counterterm'' method. The rotation breaks conformal but not scale
invariance. The AdS/CFT framework is therefore a natural arena for generating
such examples of non-trivial scale invariant theories which are not conformally
invariant.Comment: 4 pages, RevTeX (v3: references added
Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures
Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo
Recommended from our members
High-temperature superconductor applications development at Argonne National Laboratory
Developments at Argonne National Laboratory of near and intermediate term applications using high-temperature superconductors are discussed. Near-term applications of liquid-nitrogen depth sensors, current leads, and magnetic bearings are discussed in detail
- …