2,269 research outputs found
An Infinite-Dimensional Family of Black-Hole Microstate Geometries
We construct the first explicit, smooth, horizonless black-hole microstate
geometry whose moduli space is described by an arbitrary function of one
variable and is thus infinite-dimensional. This is achieved by constructing the
scalar Green function on a simple D6 anti-D6 background, and using this Green
function to obtain the fully back-reacted solution for a supertube with varying
charge density in this background. We show that this supertube can store
parametrically more entropy than in flat space, confirming the entropy
enhancement mechanism that was predicted using brane probes. We also show that
all the local properties of the fully back-reacted solution can, in fact, be
obtained using the DBI action of an appropriate brane probe. In particular, the
supergravity and the DBI analysis yield identical functional bubble equations
that govern the relative locations of the centers. This indicates that there is
a non-renormalization theorem that protects these functional equations as one
moves in moduli space. Our construction creates configurations that are beyond
the scope of recent arguments that appear to put strong limits on the entropy
that can be found in smooth supergravity solutions.Comment: 46 pages, 1 figure, LaTe
Holographic metals at finite temperature
A holographic dual description of a 2+1 dimensional system of strongly
interacting fermions at low temperature and finite charge density is given in
terms of an electron cloud suspended over the horizon of a charged black hole
in asymptotically AdS spacetime. The electron star of Hartnoll and Tavanfar is
recovered in the limit of zero temperature, while at higher temperatures the
fraction of charge carried by the electron cloud is reduced and at a critical
temperature there is a second order phase transition to a configuration with
only a charged black hole. The geometric structure implies that finite
temperature transport coefficients, including the AC electrical conductivity,
only receive contributions from bulk fermions within a finite band in the
radial direction.Comment: LaTex 16 pages, 12 figures, v2: Added reference. Error in free energy
corrected. Phase transition to AdS-RN black brane is third order rather than
second order as was claimed previousl
Microscopics of Extremal Kerr from Spinning M5 Branes
We show that the spinning magnetic one-brane in minimal five-dimensional
supergravity admits a decoupling limit that interpolates smoothly between a
self-dual null orbifold of AdS_3 \times S^2 and the near-horizon limit of the
extremal Kerr black hole times a circle. We use this interpolating solution to
understand the field theory dual to spinning M5 branes as a deformation of the
Discrete Light Cone Quantized (DLCQ) Maldacena-Stominger-Witten (MSW) CFT. In
particular, the conformal weights of the operators dual to the deformation
around AdS_3 \times S^2 are calculated. We present pieces of evidence showing
that a CFT dual to the four-dimensional extremal Kerr can be obtained from the
deformed MSW CFT.Comment: 5 page
Universality and exactness of Schrodinger geometries in string and M-theory
We propose an organizing principle for classifying and constructing
Schrodinger-invariant solutions within string theory and M-theory, based on the
idea that such solutions represent nonlinear completions of linearized vector
and graviton Kaluza-Klein excitations of AdS compactifications. A crucial
simplification, derived from the symmetry of AdS, is that the nonlinearities
appear only quadratically. Accordingly, every AdS vacuum admits infinite
families of Schrodinger deformations parameterized by the dynamical exponent z.
We exhibit the ease of finding these solutions by presenting three new
constructions: two from M5 branes, both wrapped and extended, and one from the
D1-D5 (and S-dual F1-NS5) system. From the boundary perspective, perturbing a
CFT by a null vector operator can lead to nonzero beta-functions for spin-2
operators; however, symmetry restricts them to be at most quadratic in
couplings. This point of view also allows us to easily prove nonrenormalization
theorems: for any Sch(z) solution of two-derivative supergravity constructed in
the above manner, z is uncorrected to all orders in higher derivative
corrections if the deforming KK mode lies in a short multiplet of an AdS
supergroup. Furthermore, we find infinite classes of 1/4 BPS solutions with
4-,5- and 7-dimensional Schrodinger symmetry that are exact.Comment: 31 pages, plus appendices; v2, minor corrections, added refs, slight
change in interpretation in section 2.3, new Schrodinger and Lifshitz
solutions included; v3, clarifications in sections 2 and 3 regarding
existence of solutions and multi-trace operator
Inhalation characteristics of asthma patients, COPD patients and healthy volunteers with the Spiromax® and Turbuhaler® devices: a randomised, cross-over study.
BACKGROUND: Spiromax® is a novel dry-powder inhaler containing formulations of budesonide plus formoterol (BF). The device is intended to provide dose equivalence with enhanced user-friendliness compared to BF Turbuhaler® in asthma and chronic obstructive pulmonary disease (COPD). The present study was performed to compare inhalation parameters with empty versions of the two devices, and to investigate the effects of enhanced training designed to encourage faster inhalation. METHODS: This randomised, open-label, cross-over study included children with asthma (n = 23), adolescents with asthma (n = 27), adults with asthma (n = 50), adults with COPD (n = 50) and healthy adult volunteers (n = 50). Inhalation manoeuvres were recorded with each device after training with the patient information leaflet (PIL) and after enhanced training using an In-Check Dial device. RESULTS: After PIL training, peak inspiratory flow (PIF), maximum change in pressure (∆P) and the inhalation volume (IV) were significantly higher with Spiromax than with the Turbuhaler device (p values were at least <0.05 in all patient groups). After enhanced training, numerically or significantly higher values for PIF, ∆P, IV and acceleration remained with Spiromax versus Turbuhaler, except for ∆P in COPD patients. After PIL training, one adult asthma patient and one COPD patient inhaled <30 L/min through the Spiromax compared to one adult asthma patient and five COPD patients with the Turbuhaler. All patients achieved PIF values of at least 30 L/min after enhanced training. CONCLUSIONS: The two inhalers have similar resistance so inhalation flows and pressure changes would be expected to be similar. The higher flow-related values noted for Spiromax versus Turbuhaler after PIL training suggest that Spiromax might have human factor advantages in real-world use. After enhanced training, the flow-related differences between devices persisted; increased flow rates were achieved with both devices, and all patients achieved the minimal flow required for adequate drug delivery. Enhanced training could be useful, especially in COPD patients
Efficacy of rifabutin-based triple therapy as second-line treatment to eradicate helicobacter pylori infection
<p>Abstract</p> <p>Background</p> <p>Rifabutin has been found to be effective in multi-resistant patients after various treatment cycles for Helicobacter pylori (HP) infection, but it has not been analysed as a second-line treatment. Therefore, we seek to compare the effectiveness of a treatment regimen including rifabutin versus conventional quadruple therapy (QT).</p> <p>Methods</p> <p>Open clinical trial, randomised and multi-centre, of two treatment protocols: A) Conventional regime -QT- (omeprazole 20 mg bid, bismuth citrate 120 mg qid, tetracycline 500 mg qid and metronidazole 500 mg tid); B) Experimental one -OAR- (omeprazole 20 mg bid, amoxicillin 1 gr bid, and rifabutin 150 mg bid), both taken orally for 7 days, in patients with HP infection for whom first-line treatment had failed. Eradication was determined by Urea Breath Test (UBT). Safety was determined by the adverse events.</p> <p>Results</p> <p>99 patients were randomised, QT, n = 54; OAR, n = 45. The two groups were homogeneous. In 8 cases, treatment was suspended (6 in QT and 2 in OAR). The eradication achieved, analysed by ITT, was for QT, 38 cases (70.4%), and for OAR, 20 cases (44.4%); p = 0.009, OR = 1.58. Of the cases analysed PP, QT were 77.1%; OAR, 46.5%; p = 0.002. Adverse effects were described in 64% of the QT patients and in 44% of the OAR patients (p = 0.04).</p> <p>Conclusion</p> <p>A 7-day rifabutin-based triple therapy associated to amoxicillin and omeprazole at standard dose was not found to be effective as a second-line rescue therapy. The problem with quadruple therapy lies in the adverse side effects it provokes. We believe the search should continue for alternatives that are more comfortably administered and that are at least as effective, but with fewer adverse side effects.</p> <p>Trial Registration</p> <p>Current Controlled Trials ISRCTN81058036</p
Distinct molecular signature of phospholamban p.Arg14del arrhythmogenic cardiomyopathy.
Phospholamban (PLN) p.Arg14del cardiomyopathy is characterized by a distinct arrhythmogenic biventricular phenotype that can be predominantly left ventricular, right ventricular, or both. Our aim was to further elucidate distinct features of this cardiomyopathy with respect to the distribution of desmosomal proteins observed by immunofluorescence (IF) in comparison to desmosomal arrhythmogenic cardiomyopathy and co-existent genetic variants. We studied eight explanted heart specimens from PLN p.Arg14del mutation carriers. Macro- and microscopic examination revealed biventricular presence of fibrofatty replacement and interstitial fibrosis. Five out of 8 (63%) patients met consensus criteria for both arrhythmogenic right ventricular cardiomyopathy (ARVC) and dilated cardiomyopathy (DCM). In four cases, targeted next-generation sequencing revealed one additional pathogenic variant and six variants of unknown significance. IF showed diminished junction plakoglobin signal intensity at the intercalated disks in 4 (67%) out of 6 cases fulfilling ARVC criteria but normal intensity in both cases fulfilling only DCM criteria. Notably, the four cases with diminished junction plakoglobin were also those where an additional gene variant was detected. IF for two proteins recently investigated in desmosomal arrhythmogenic cardiomyopathy (ACM), synapse-associated protein 97 and glycogen synthase kinase-3 beta, showed a distinct distributional pattern in comparison to desmosomal ACM. In 7 (88%) out of 8 cases we observed both a strong synapse-associated protein 97 signal at the sarcomeres and no glycogen synthase kinase-3 beta translocation to the intercalated discs. Phospholamban p.Arg14del cardiomyopathy is characterized by a distinct molecular signature compared to desmosomal ACM, specifically a different desmosomal protein distribution. This study substantiates the idea that additional genetic variants play a role in the phenotypical heterogeneity
BPS States, Refined Indices, and Quiver Invariants
For D=4 BPS state construction, counting, and wall-crossing thereof, quiver
quantum mechanics offers two alternative approaches, the Coulomb phase and the
Higgs phase, which sometimes produce inequivalent counting. The authors have
proposed, in arXiv:1205.6511, two conjectures on the precise relationship
between the two, with some supporting evidences. Higgs phase ground states are
naturally divided into the Intrinsic Higgs sector, which is insensitive to
wall-crossings and thus an invariant of quiver, plus a pulled-back ambient
cohomology, conjectured to be an one-to-one image of Coulomb phase ground
states. In this note, we show that these conjectures hold for all cyclic
quivers with Abelian nodes, and further explore angular momentum and R-charge
content of individual states. Along the way, we clarify how the protected spin
character of BPS states should be computed in the Higgs phase, and further
determine the entire Hodge structure of the Higgs phase cohomology. This shows
that, while the Coulomb phase states are classified by angular momentum, the
Intrinsic Higgs states are classified by R-symmetry.Comment: 51 pages, 5 figure
Economic factors influencing zoonotic disease dynamics: demand for poultry meat and seasonal transmission of avian influenza in Vietnam
While climate is often presented as a key factor influencing the seasonality of diseases, the importance of anthropogenic factors is less commonly evaluated. Using a combination of methods-wavelet analysis, economic analysis, statistical and disease transmission modelling-we aimed to explore the influence of climatic and economic factors on the seasonality of H5N1 Highly Pathogenic Avian Influenza in the domestic poultry population of Vietnam. We found that while climatic variables are associated with seasonal variation in the incidence of avian influenza outbreaks in the North of the country, this is not the case in the Centre and the South. In contrast, temporal patterns of H5N1 incidence are similar across these 3 regions: periods of high H5N1 incidence coincide with Lunar New Year festival, occurring in January-February, in the 3 climatic regions for 5 out of the 8 study years. Yet, daily poultry meat consumption drastically increases during Lunar New Year festival throughout the country. To meet this rise in demand, poultry production and trade are expected to peak around the festival period, promoting viral spread, which we demonstrated using a stochastic disease transmission model. This study illustrates the way in which economic factors may influence the dynamics of livestock pathogens
- …