1,902 research outputs found
Graviton 1-loop partition function for 3-dimensional massive gravity
The graviton 1-loop partition function in Euclidean topologically massive
gravity (TMG) is calculated using heat kernel techniques. The partition
function does not factorize holomorphically, and at the chiral point it has the
structure expected from a logarithmic conformal field theory. This gives strong
evidence for the proposal that the dual conformal field theory to TMG at the
chiral point is indeed logarithmic. We also generalize our results to new
massive gravity.Comment: 19 pages, v2: major revision, considerably stronger conclusions,
added comparison with LCFT partition function, confirmation of LCFT
conjecture, added autho
Microcavity controlled coupling of excitonic qubits
Controlled non-local energy and coherence transfer enables light harvesting
in photosynthesis and non-local logical operations in quantum computing. The
most relevant mechanism of coherent coupling of distant qubits is coupling via
the electromagnetic field. Here, we demonstrate the controlled coherent
coupling of spatially separated excitonic qubits via the photon mode of a solid
state microresonator. This is revealed by two-dimensional spectroscopy of the
sample's coherent response, a sensitive and selective probe of the coherent
coupling. The experimental results are quantitatively described by a rigorous
theory of the cavity mediated coupling within a cluster of quantum dots
excitons. Having demonstrated this mechanism, it can be used in extended
coupling channels - sculptured, for instance, in photonic crystal cavities - to
enable a long-range, non-local wiring up of individual emitters in solids
Critical solutions in topologically gauged N=8 CFTs in three dimensions
In this paper we discuss some special (critical) background solutions that
arise in topological gauged three-dimensional CFTs with SO(N)
gauge group. These solutions solve the TMG equations (containing the parameters
and ) for a certain set of values of obtained by varying the
number of scalar fields with a VEV. Apart from Minkowski, chiral round
and null-warped (or Schr\"odinger(z=2)) we identify also a more exotic
solution recently found in by Ertl, Grumiller and Johansson. We also
discuss the spectrum, symmetry breaking pattern and the supermultiplet
structure in the various backgrounds and argue that some properties are due to
their common origin in a conformal phase. Some of the scalar fields, including
all higgsed ones, turn out to satisfy three-dimensional singleton field
equations. Finally, we note that topologically gauged ABJ(M)
theories have a similar, but more restricted, set of background solutions.Comment: 34 pages, v2: minor corrections, note about a new solution added in
final section, v3: two footnotes adde
Numerical instability of the Akhmediev breather and a finite-gap model of it
In this paper we study the numerical instabilities of the NLS Akhmediev
breather, the simplest space periodic, one-mode perturbation of the unstable
background, limiting our considerations to the simplest case of one unstable
mode. In agreement with recent theoretical findings of the authors, in the
situation in which the round-off errors are negligible with respect to the
perturbations due to the discrete scheme used in the numerical experiments, the
split-step Fourier method (SSFM), the numerical output is well-described by a
suitable genus 2 finite-gap solution of NLS. This solution can be written in
terms of different elementary functions in different time regions and,
ultimately, it shows an exact recurrence of rogue waves described, at each
appearance, by the Akhmediev breather. We discover a remarkable empirical
formula connecting the recurrence time with the number of time steps used in
the SSFM and, via our recent theoretical findings, we establish that the SSFM
opens up a vertical unstable gap whose length can be computed with high
accuracy, and is proportional to the inverse of the square of the number of
time steps used in the SSFM. This neat picture essentially changes when the
round-off error is sufficiently large. Indeed experiments in standard double
precision show serious instabilities in both the periods and phases of the
recurrence. In contrast with it, as predicted by the theory, replacing the
exact Akhmediev Cauchy datum by its first harmonic approximation, we only
slightly modify the numerical output. Let us also remark, that the first rogue
wave appearance is completely stable in all experiments and is in perfect
agreement with the Akhmediev formula and with the theoretical prediction in
terms of the Cauchy data.Comment: 27 pages, 8 figures, Formula (30) at page 11 was corrected, arXiv
admin note: text overlap with arXiv:1707.0565
Cardiogenic shock following administration of propofol and fentanyl in a healthy woman: a case report
<p>Abstract</p> <p>Introduction</p> <p>Cardiogenic shock is very uncommon in healthy people. The differential diagnosis for patients with acute heart failure in previously healthy hearts includes acute myocardial infarction and myocarditis. However, many drugs can also depress myocardial function. Propofol and fentanyl are frequently used during different medical procedures. The cardiovascular depressive effect of both drugs has been well established, but the development of cardiogenic shock is very rare when these agents are used.</p> <p>Case presentation</p> <p>After a minor surgical intervention, a 32-year-old Caucasian woman with no significant medical history went into sudden hemodynamic deterioration due to acute heart failure. An urgent echocardiogram showed severe biventricular dysfunction and an estimated left ventricular ejection fraction of 20%. Extracorporeal life support and mechanical ventilation were required. Five days later her ventricular function had fully recovered, which allowed the progressive withdrawal of medical treatment. Prior to her hospital discharge, cardiac MRI showed neither edema nor pathological deposits on the delayed contrast enhancement sequences. At her six-month follow-up examination, the patient was asymptomatic and did not require treatment.</p> <p>Conclusion</p> <p>Although there are many causes of cardiogenic shock, the presence of abrupt hemodynamic deterioration and the absence of a clear cause could be related to the use of propofol and fentanyl.</p
Holography For a De Sitter-Esque Geometry
Warped dS arises as a solution to topologically massive gravity (TMG)
with positive cosmological constant and Chern-Simons coefficient
in the region . It is given by a real line fibration
over two-dimensional de Sitter space and is equivalent to the rotating Nariai
geometry at fixed polar angle. We study the thermodynamic and asymptotic
structure of a family of geometries with warped dS asymptotics.
Interestingly, these solutions have both a cosmological horizon and an internal
one, and their entropy is unbounded from above unlike black holes in regular de
Sitter space. The asymptotic symmetry group resides at future infinity and is
given by a semi-direct product of a Virasoro algebra and a current algebra. The
right moving central charge vanishes when . We discuss the
possible holographic interpretation of these de Sitter-esque spacetimes.Comment: 22 pages, 1 figure; v2: typos corrected, to match with published
versio
Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.
BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
Infrared (810-nm) low-level laser therapy on rat experimental knee inflammation
Arthritis of the knee is the most common type of joint inflammatory disorder and it is associated with pain and inflammation of the joint capsule. Few studies address the effects of the 810-nm laser in such conditions. Here we investigated the effects of low-level laser therapy (LLLT; infrared, 810-nm) in experimentally induced rat knee inflammation. Thirty male Wistar rats (230–250 g) were anesthetized and injected with carrageenan by an intra-articular route. After 6 and 12 h, all animals were killed by CO2 inhalation and the articular cavity was washed for cellular and biochemical analysis. Articular tissue was carefully removed for real-time PCR analysis in order to evaluate COX-1 and COX-2 expression. LLLT was able to significantly inhibit the total number of leukocytes, as well as the myeloperoxidase activity with 1, 3, and 6 J (Joules) of energy. This result was corroborated by cell counting showing the reduction of polymorphonuclear cells at the inflammatory site. Vascular extravasation was significantly inhibited at the higher dose of energy of 10 J. Both COX-1 and 2 gene expression were significantly enhanced by laser irradiation while PGE2 production was inhibited. Low-level laser therapy operating at 810 nm markedly reduced inflammatory signs of inflammation but increased COX-1 and 2 gene expression. Further studies are necessary to investigate the possible production of antiinflammatory mediators by COX enzymes induced by laser irradiation in knee inflammation
The Imperfect Fluid behind Kinetic Gravity Braiding
We present a standard hydrodynamical description for non-canonical scalar
field theories with kinetic gravity braiding. In particular, this picture
applies to the simplest galileons and k-essence. The fluid variables not only
have a clear physical meaning but also drastically simplify the analysis of the
system. The fluid carries charges corresponding to shifts in field space. This
shift-charge current contains a spatial part responsible for diffusion of the
charges. Moreover, in the incompressible limit, the equation of motion becomes
the standard diffusion equation. The fluid is indeed imperfect because the
energy flows neither along the field gradient nor along the shift current. The
fluid has zero vorticity and is not dissipative: there is no entropy
production, the energy-momentum is exactly conserved, the temperature vanishes
and there is no shear viscosity. Still, in an expansion around a perfect fluid
one can identify terms which correct the pressure in the manner of bulk
viscosity. We close by formulating the non-trivial conditions for the
thermodynamic equilibrium of this imperfect fluid.Comment: 23 pages plus appendices. New version includes extended discussion on
diffusion and dynamics in alternative frames, as well as additional
references. v3 reflects version accepted for publication in JHEP: minor
comments added regarding suitability to numerical approache
Understanding psychiatric institutionalization: a conceptual review
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
- …