1,392 research outputs found
D-Brane Potentials from Multi-Trace Deformations in AdS/CFT
It is known that certain AdS boundary conditions allow smooth initial data to
evolve into a big crunch. To study this type of cosmological singularity, one
can use the dual quantum field theory, where the non-standard boundary
conditions are reflected by the presence of a multi-trace potential unbounded
below. For specific AdS_4 and AdS_5 models, we provide a D-brane (or M-brane)
interpretation of the unbounded potential. Using probe brane computations, we
show that the AdS boundary conditions of interest cause spherical branes to be
pushed to the boundary of AdS in finite time, and that the corresponding
potential agrees with the multi-trace deformation of the dual field theory.
Systems with expanding spherical D3-branes are related to big crunch
supergravity solutions by a phenomenon similar to geometric transition.Comment: 26 pages, 3 figures, v4: a few typos fixed
Efficacy and Safety of Radium-223 Dichloride in Symptomatic Castration-resistant Prostate Cancer Patients With or Without Baseline Opioid Use From the Phase 3 ALSYMPCA Trial
Background: The phase 3 ALSYMPCA trial enrolled metastatic castration-resistant prostate
cancer patients with or without baseline opioid use.
Objective: To assess the efficacy and safety of radium-223 dichloride (radium-223) versus
placebo in ALSYMPCA patients by baseline opioid use.
Design, setting, and participants: Nine hundred and twenty one patients enrolled at 136 centers
globally.
Intervention: Radium-223 (50 kBq/kg, intravenous injection) every 4 wk for six cycles or
matching placebo, each plus best standard of care.
Outcome measurements and statistical analysis: Primary endpoint (overall survival [OS]),
main secondary efficacy endpoints, and safety were evaluated by baseline opioid use.
Additional analyses included time to first opioid use, time to first external beam radiation
therapy for bone pain, and safety of concomitant external beam radiation therapy.
Results and limitations: At baseline, 408 (44%) patients had no pain and no analgesic use or
mild pain with nonopioid therapy (World Health Organization ladder pain score 0–1 [nonopioid
subgroup]), and 513 (56%) had moderate pain with occasional opioids or severe pain
with regular daily opioids (World Health Organization ladder pain score 2–3 [opioid subgroup]).
Radium-223 significantly prolonged OS versus placebo in nonopioid (hazard ratio
[HR] = 0.70; 95% confidence interval [CI]: 0.52–0.93; p = 0.013) and opioid (HR = 0.68; 95% CI:
0.54–0.86; p = 0.001) subgroups, and significantly reduced risk of symptomatic skeletal events
versus placebo, regardless of baseline opioid use (nonopioid subgroup: HR = 0.56, 95% CI: 0.39–
0.82, p = 0.002; opioid subgroup: HR = 0.72, 95% CI: 0.53–0.98, p = 0.038). Time to first opioid
use for bone pain was significantly delayed with radium-223 versus placebo (HR = 0.62, 95% CI:
0.46–0.85, p = 0.002). Adverse event incidences were similar between opioid subgroups.
Conclusions: Radium-223 versus placebo significantly prolonged OS and reduced symptomatic
skeletal event risk with a favorable safety profile in castration-resistant prostate cancer
patients with symptomatic bone metastases, regardless of baseline opioid use.
Patient summary: In this ALSYMPCA opioid subgroup analysis, baseline symptom levels did
not appear to impact radium-223 dichloride efficacy or safet
Dietary fibre may mitigate sarcopenia risk:Findings from the NU-AGE cohort of older european adults
Sarcopenia is characterised by a progressive loss of skeletal muscle mass and physical function as well as related metabolic disturbances. While fibre-rich diets can influence metabolic health outcomes, the impact on skeletal muscle mass and function is yet to be determined, and the moderating effects by physical activity (PA) need to be considered. The aim of the present study was to examine links between fibre intake, skeletal muscle mass and physical function in a cohort of older adults from the NU-AGE study. In 981 older adults (71 ± 4 years, 58% female), physical function was assessed using the short-physical performance battery test and handgrip strength. Skeletal muscle mass index (SMI) was derived using dual-energy X-ray absorptiometry (DXA). Dietary fibre intake (FI) was assessed by 7-day food record and PA was objectively determined by accelerometery. General linear models accounting for covariates including PA level, protein intake and metabolic syndrome (MetS) were used. Women above the median FI had significantly higher SMI compared to those below, which remained in fully adjusted models (24.7 ± 0.2% vs. 24.2 ± 0.1%, p = 0.011, η2p = 0.012). In men, the same association was only evident in those without MetS (above median FI: 32.4 ± 0.3% vs. below median FI: 31.3 ± 0.3%, p = 0.005, η2p = 0.035). There was no significant impact of FI on physical function outcomes. The findings from this study suggest a beneficial impact of FI on skeletal muscle mass in older adults. Importantly, this impact is independent of adherence to guidelines for protein intake and PA, which further strengthens the potential role of dietary fibre in preventing sarcopenia. Further experimental work is warranted in order to elucidate the mechanisms underpinning the action of dietary fibre on the regulation of muscle mass
The cohomology of superspace, pure spinors and invariant integrals
The superform construction of supersymmetric invariants, which consists of
integrating the top component of a closed superform over spacetime, is
reviewed. The cohomological methods necessary for the analysis of closed
superforms are discussed and some further theoretical developments presented.
The method is applied to higher-order corrections in heterotic string theory up
to \a'^3. Some partial results on and are also given.Comment: 24 pages. Minor changes; added reference
Correlation between muonic levels and nuclear structure in muonic atoms
A method that deals with the nucleons and the muon unitedly is employed to
investigate the muonic lead, with which the correlation between the muon and
nucleus can be studied distinctly. A "kink" appears in the muonic isotope shift
at a neutron magic number where the nuclear shell structure plays a key role.
This behavior may have very important implications for the experimentally
probing the shell structure of the nuclei far away from the -stable
line. We investigate the variations of the nuclear structure due to the
interaction with the muon in the muonic atom and find that the nuclear
structure remains basically unaltered. Therefore, the muon is a clean and
reliable probe for studying the nuclear structure. In addition, a correction
that the muon-induced slight change in the proton density distribution in turn
shifts the muonic levels is investigated. This correction to muonic level is as
important as the Lamb shift and high order vacuum polarization correction, but
is larger than anomalous magnetic moment and electron shielding correction.Comment: 2 figure
The presence of lateral photophores correlates with increased speciation in deep-sea bioluminescent sharks
The vast majority of species within the lanternshark genus Etmopterus harbour complex luminescent markings on their flanks, whose functional significance has long remained obscure. Recent studies, however, suggest these enigmatic photophore aggregations to play a role in intraspecific communication. Using visual modelling based on in vivo luminescence measurements from a common lanternshark species, we show that etmopterid flank markings can potentially work as a medium range signal for intraspecific detection/recognition. In addition, using molecular phylogenetic analyses, we demonstrate that the Etmopterus clade exhibits a greater than expected species richness given its age. This is not the case for other bioluminescent shark clades with no (or only few) species with flank markings. Our results therefore suggest that etmopterid flank markings may provide a way for reproductive isolation and hence may have facilitated speciation in the deep-sea
Deformation independent open brane metrics and generalized theta parameters
We investigate the consequences of generalizing certain well established
properties of the open string metric to the conjectured open membrane and open
Dp-brane metrics. By imposing deformation independence on these metrics their
functional dependence on the background fields can be determined including the
notorious conformal factor. In analogy with the non-commutativity parameter
in the string case, we also obtain `generalized' theta
parameters which are rank q+1 antisymmetric tensors (polyvectors) for open
Dq-branes and rank 3 for the open membrane case. The expressions we obtain for
the open membrane quantities are expected to be valid for general background
field configurations, while the open D-brane quantities are only valid for one
parameter deformations. By reducing the open membrane data to five dimensions,
we show that they, modulo a subtlety with implications for the relation between
OM-theory and NCYM, correctly generate the open string and open D2-data.Comment: 24 pages, LaTe
Biomechanical and morphological study of a new elastic mesh (Ciberlastic) to repair abdominal wall defects
The aim of this study was to conduct a preclinical evaluation of the behaviour of a new type of abdominal LW prosthesis (Ciberlastic), which was designed with a non-absorbable elastic polyurethane monofilament (Assuplus, Assut Europe, Italy) to allow greater adaptability to mechanical area requirements and higher bio-mimicking with the newly formed surrounding tissues. Our hypothesis was that an increase in the elasticity of the mesh filament could improve the benefits of LW prostheses. To verify our hypothesis, we compared the short- and long-term behaviour of Ciberlastic and Optilene® elastic commercial meshes by repairing the partially herniated abdomen in New Zealand White rabbits. The implanted meshes were mechanically and histologically assessed at 14 and 180 days post-implant. We mechanically characterized the partially herniated repaired muscle tissue and also determined mesh shrinkage at different post-implant times. This was followed by a histological study in which the tissue incorporation process was analysed over time. The new prosthesis designed by our group achieved good behaviour that was similar to that of Optilene®, one of the most popular LW prostheses on the market, with the added advantage of its elastic property. The mechanical properties are significantly lower than those of the polypropylene Optilene® mesh, and the new elastic mesh meets the basic mechanical requirements for positioning in the abdominal wall, which was also demonstrated by the absence of recurrences after implantation in the experimental model. We found that the growth of a connective tissue rich in collagen over the hernial defect and the proper deposit of the collagen fibres in the regenerated tissue substantially modified the original properties of the mesh, thereby increasing its biomechanical strength and making the whole tissue/mesh stiffer
Supergravity Duals of Noncommutative Wrapped D6 Branes and Supersymmetry without Supersymmetry
We construct the supergravity solution in 11 dimensions describing D6-branes
wrapped around a Kahler four-cycle with a B-field along the flat directions of
the brane. The configuration is dual to an N=2 noncommutative gauge theory in
2+1 dimensions. We also construct the four associated independent Killing
spinors. The phenomenon of supersymmetry without supersymmetry appears
naturally when compactifying to type IIA or 8d gauged supergravity. Therefore,
this solution also provides an 11d background with four supercharges and
four-form flux, which is not obtainable from 8d gauged supergravity.Comment: 17 pages. One typo, few comments and 1 reference adde
Measuring Black Hole Spin in OJ287
We model the binary black hole system OJ287 as a spinning primary and a
non-spinning secondary. It is assumed that the primary has an accretion disk
which is impacted by the secondary at specific times. These times are
identified as major outbursts in the light curve of OJ287. This identification
allows an exact solution of the orbit, with very tight error limits. Nine
outbursts from both the historical photographic records as well as from recent
photometric measurements have been used as fixed points of the solution: 1913,
1947, 1957, 1973, 1983, 1984, 1995, 2005 and 2007 outbursts. This allows the
determination of eight parameters of the orbit. Most interesting of these are
the primary mass of , the secondary mass , major axis precession rate per period, and the
eccentricity of the orbit 0.70. The dimensionless spin parameter is
(1 sigma). The last parameter will be more tightly
constrained in 2015 when the next outburst is due. The outburst should begin on
15 December 2015 if the spin value is in the middle of this range, on 3 January
2016 if the spin is 0.25, and on 26 November 2015 if the spin is 0.31. We have
also tested the possibility that the quadrupole term in the Post Newtonian
equations of motion does not exactly follow Einstein's theory: a parameter
is introduced as one of the 8 parameters. Its value is within 30% (1 sigma) of
the Einstein's value . This supports the of black
holes within the achievable precision. We have also measured the loss of
orbital energy due to gravitational waves. The loss rate is found to agree with
Einstein's value with the accuracy of 2% (1 sigma).Comment: 12 pages, 4 figures, IAU26
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