1,598 research outputs found
Parent formulation at the Lagrangian level
The recently proposed first-order parent formalism at the level of equations
of motion is specialized to the case of Lagrangian systems. It is shown that
for diffeomorphism-invariant theories the parent formulation takes the form of
an AKSZ-type sigma model. The proposed formulation can be also seen as a
Lagrangian version of the BV-BRST extension of the Vasiliev unfolded approach.
We also discuss its possible interpretation as a multidimensional
generalization of the Hamiltonian BFV--BRST formalism. The general construction
is illustrated by examples of (parametrized) mechanics, relativistic particle,
Yang--Mills theory, and gravity.Comment: 26 pages, discussion of the truncation extended, typos corrected,
references adde
Wilson-loop formalism for Reggeon exchange in soft high-energy scattering
We derive a nonperturbative expression for the non-vacuum,
qqbar-Reggeon-exchange contribution to the meson-meson elastic scattering
amplitude at high energy and low momentum transfer, in the framework of QCD.
Describing the mesons in terms of colourless qqbar dipoles, the problem is
reduced to the two-fermion-exchange contribution to the dipole-dipole
scattering amplitudes, which is expressed as a path integral, over the
trajectories of the exchanged fermions, of the expectation value of a certain
Wilson loop. We also show how the resulting expression can be reconstructed
from a corresponding quantity in the Euclidean theory, by means of analytic
continuation. Finally, we make contact with previous work on Reggeon exchange
in the gauge/gravity duality approach.Comment: A few misprints in the expressions for the relevant Wilson loops have
been corrected. 55 pages, 7 figure
Brain ventricular dimensions and relationship to outcome in adult patients with bacterial meningitis
Progressive Multiple Sclerosis Is Associated with Accelerated Inner and Outer Retinal Layer Atrophy
Short-term efficacy of physical interventions in osteoarthritic knee pain. A systematic review and meta-analysis of randomised placebo-controlled trials.
BACKGROUND: Treatment efficacy of physical agents in osteoarthritis of the knee (OAK) pain has been largely unknown, and this systematic review was aimed at assessing their short-term efficacies for pain relief. METHODS: Systematic review with meta-analysis of efficacy within 1-4 weeks and at follow up at 1-12 weeks after the end of treatment. RESULTS: 36 randomised placebo-controlled trials (RCTs) were identified with 2434 patients where 1391 patients received active treatment. 33 trials satisfied three or more out of five methodological criteria (Jadad scale). The patient sample had a mean age of 65.1 years and mean baseline pain of 62.9 mm on a 100 mm visual analogue scale (VAS). Within 4 weeks of the commencement of treatment manual acupuncture, static magnets and ultrasound therapies did not offer statistically significant short-term pain relief over placebo. Pulsed electromagnetic fields offered a small reduction in pain of 6.9 mm [95% CI: 2.2 to 11.6] (n = 487). Transcutaneous electrical nerve stimulation (TENS, including interferential currents), electro-acupuncture (EA) and low level laser therapy (LLLT) offered clinically relevant pain relieving effects of 18.8 mm [95% CI: 9.6 to 28.1] (n = 414), 21.9 mm [95% CI: 17.3 to 26.5] (n = 73) and 17.7 mm [95% CI: 8.1 to 27.3] (n = 343) on VAS respectively versus placebo control. In a subgroup analysis of trials with assumed optimal doses, short-term efficacy increased to 22.2 mm [95% CI: 18.1 to 26.3] for TENS, and 24.2 mm [95% CI: 17.3 to 31.3] for LLLT on VAS. Follow-up data up to 12 weeks were sparse, but positive effects seemed to persist for at least 4 weeks after the course of LLLT, EA and TENS treatment was stopped. CONCLUSION: TENS, EA and LLLT administered with optimal doses in an intensive 2-4 week treatment regimen, seem to offer clinically relevant short-term pain relief for OAK
Discovery of the Onset of Rapid Accretion by a Dormant Massive Black Hole
Massive black holes are believed to reside at the centres of most galaxies.
They can be- come detectable by accretion of matter, either continuously from a
large gas reservoir or impulsively from the tidal disruption of a passing star,
and conversion of the gravitational energy of the infalling matter to light.
Continuous accretion drives Active Galactic Nuclei (AGN), which are known to be
variable but have never been observed to turn on or off. Tidal disruption of
stars by dormant massive black holes has been inferred indirectly but the on-
set of a tidal disruption event has never been observed. Here we report the
first discovery of the onset of a relativistic accretion-powered jet in the new
extragalactic transient, Swift J164449.3+573451. The behaviour of this new
source differs from both theoretical models of tidal disruption events and
observations of the jet-dominated AGN known as blazars. These differences may
stem from transient effects associated with the onset of a powerful jet. Such
an event in the massive black hole at the centre of our Milky Way galaxy could
strongly ionize the upper atmosphere of the Earth, if beamed towards us.Comment: Submitted to Nature. 4 pages, 3 figures (main paper). 26 pages, 13
figures (supplementary information
The association of body size in early to mid-life with adult urinary 6-sulfatoxymelatonin levels among night shift health care workers
Intracranial tumors of the central nervous system and air pollution - A nationwide case-control study from Denmark
Background: Inconclusive evidence has suggested a possible link between air pollution and central nervous
system (CNS) tumors. We investigated a range of air pollutants in relation to types of CNS tumors.
Methods: We identified all (n = 21,057) intracranial tumors in brain, meninges and cranial nerves diagnosed in
Denmark between 1989 and 2014 and matched controls on age, sex and year of birth. We established personal 10-
year mean residential outdoor exposure to particulate matter < 2.5 μm (PM2.5), nitrous oxides (NOX), primary emitted
black carbon (BC) and ozone. We used conditional logistic regression to calculate odds ratios (OR) linearly (per
interquartile range (IQR)) and categorically. We accounted for personal income, employment, marital status, use of
medication as well as socio-demographic conditions at area level.
Results: Malignant tumors of the intracranial CNS was associated with BC (OR: 1.034, 95%CI: 1.005–1.065 per IQR.
For NOx the OR per IQR was 1.026 (95%CI: 0.998–1.056). For malignant non-glioma tumors of the brain we found
associations with PM2.5 (OR: 1.267, 95%CI: 1.053–1.524 per IQR), BC (OR: 1.049, 95%CI: 0.996–1.106) and NOx (OR:
1.051, 95% CI: 0.996–1.110).
Conclusion: Our results suggest that air pollution is associated with malignant intracranial CNS tumors and
malignant non-glioma of the brain. However, additional studies are needed
Dietary methyl donors, methyl metabolizing enzymes, and epigenetic regulators: diet–gene interactions and promoter CpG island hypermethylation in colorectal cancer
Dietary methyl donors might influence DNA methylation during carcinogenesis of colorectal cancer (CRC). Among 609 CRC cases and 1,663 subcohort members of the Netherlands Cohort Study on diet and cancer (n = 120,852), we estimated CRC risk according to methyl donor intake across genotypes of folate metabolizing enzymes and methyltransferases
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