163 research outputs found
Parity violating vertices for spin-3 gauge fields
peer reviewedThe problem of constructing consistent parity-violating interactions for spin-3 gauge fields is considered in Minkowski space. Under the assumptions of locality, Poincaré invariance, and parity noninvariance, we classify all the nontrivial perturbative deformations of the Abelian gauge algebra. In space-time dimensions n=3 and n=5, deformations of the free theory are obtained which make the gauge algebra non-Abelian and give rise to nontrivial cubic vertices in the Lagrangian, at first order in the deformation parameter g. At second order in g, consistency conditions are obtained which the five-dimensional vertex obeys, but which rule out the n=3 candidate. Moreover, in the five-dimensional first-order deformation case, the gauge transformations are modified by a new term which involves the second de Wit-Freedman connection in a simple and suggestive way
Strong obstruction of the Berends-Burgers-van Dam spin-3 vertex
In the eighties, Berends, Burgers and van Dam (BBvD) found a nonabelian cubic
vertex for self-interacting massless fields of spin three in flat spacetime.
However, they also found that this deformation is inconsistent at higher order
for any multiplet of spin-three fields. For arbitrary symmetric gauge fields,
we severely constrain the possible nonabelian deformations of the gauge algebra
and, using these results, prove that the BBvD obstruction cannot be cured by
any means, even by introducing fields of spin higher (or lower) than three.Comment: 19 pages, no figur
0432: Impact of early complications on outcomes among patients with implantable cardioverter defibrillator in primary prevention
BackgroundThe life-saving benefit of implantable cardioverter defibrillators (ICD) has been well demonstrated, and therefore their utilization has considerably grown in the last 10 years. At the same time, complications have become an increasingly important concern.ObjectivesThis study aimed to assess the prevalence and impact on outcomes (late complications and overall mortality) of early complications after ICD implantation for primary prevention in a large French population.MethodsFrom a multicentric French registry (DAI-PP Registry, 2002-2012), 5547 consecutive patients, with coronary artery disease or dilated cardiomyopathy, were implanted with an ICD in the setting of primary prevention. From 5338 (96%) patients with full information, we determined prevalence, independent associated factors and prognosis of the occurrence of early (within 30 days post implantation) complications.ResultsEarly complications occurred in 709 patients (13.5%), mainly related to lead dysfunction or hematoma (56%). Independent associated factors to early complications were renla impairment (clearance <30ml/min, OR=1.69, 95% CI 1.19-2.41, P<0.001), cardiac resynchronization therapy (OR=1.61, 95% CI 1.17-2.21, P=0.004), anticoagulant therapy (OR=1.30, 95% CI 1.04-1.63, P=0.02) and older age (OR=1.02, 95% CI 1.01-1.02, P=0.03). During a mean follow-up of 3.1±2.3 years, 834 patients experienced ≥1 complication (15.6%), mainly inappropriate therapies and/or lead dysfunction (75%). After consideration of potential confounding factors, early complications were significantly associated with the occurrence of late complications (OR=2.15, 95% CI 1.73-2.66, P<0.0001) and a higher risk of overall mortality (OR=1.48, 95% CI 1.17-1.88, P=0.001).ConclusionsEarly complication is a frequent event after ICD implantation occurring in one out of six patients. These events are associated with a significant increase of late complications and overall mortality
Consistent couplings between spin-2 and spin-3 massless fields
We solve the problem of constructing consistent first-order
cross-interactions between spin-2 and spin-3 massless fields in flat spacetime
of arbitrary dimension n > 3 and in such a way that the deformed gauge algebra
is non-Abelian. No assumptions are made on the number of derivatives involved
in the Lagrangian, except that it should be finite. Together with locality, we
also impose manifest Poincare invariance, parity invariance and analyticity of
the deformations in the coupling constants.Comment: LaTeX file. 29 pages, no figures. Minor corrections. Accepted for
publication in JHE
Impact of early complications on outcomes in patients with implantable cardioverter-defibrillator for primary prevention
International audienceBackground - The lifesaving benefit of implantable cardioverter-defibrillators (ICDs) has been demonstrated. Their use has increased considerably in the past decade, but related complications have become a major concern. Objective - The purpose of this study was to assess the incidence and effect on outcomes of early (≤30 days) complications after ICD implantation for primary prevention in a large French population. Methods - We analyzed data from 5539 patients from the multicenter French DAI-PP (Défibrillateur Automatique Implantable-Prévention Primaire) registry (2002-2012) who had coronary artery disease or dilated cardiomyopathy and were implanted with an ICD for primary prevention. Results - Overall, early complications occurred in 707 patients (13.5%), mainly related to lead dislodgment or hematoma (57%). Independent factors associated with occurrence of early complications were severe renal impairment (odds ratio [OR] 1.66, 95% confidence interval [CI] 1.17-2.37, P = .02), age ≥75 years (OR 1.01, 95% CI 1.00-1.02, P = .03), cardiac resynchronization therapy (OR 1.58, 95% CI 1.16-2.17, P = .01), and anticoagulant therapy (OR 1.28, 95% CI 1.02-1.61, P = .03). During a mean ± SD follow-up of 3.1 ± 2.3 years, 824 (15.8%) patients experienced ≥1 late complication (>30 days), and 782 (14.9%) patients died. After adjustment, early complications remained associated with occurrence of late complications (OR 2.15, 95% CI 1.73-2.66, P < .0001) and mortality (OR 1.70, 95% CI 1.34-2.17, P = .003). Conclusion - Early complications are common after ICD implantation for primary prevention, occurring in 1 in 7 patients, and are associated with an increased risk of late complications and overall mortality. Further studies are needed to investigate the underlying mechanisms of such associations
Early diagnosis and better rhythm management to improve outcomes in patients with atrial fibrillation: the 8th AFNET/EHRA consensus conference
Despite marked progress in the management of atrial fibrillation (AF), detecting AF remains difficult and AF-related complications cause unacceptable morbidity and mortality even on optimal current therapy. This document summarizes the key outcomes of the 8th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA). Eighty-three international experts met in Hamburg for 2 days in October 2021. Results of the interdisciplinary, hybrid discussions in breakout groups and the plenary based on recently published and unpublished observations are summarized in this consensus paper to support improved care for patients with AF by guiding prevention, individualized management, and research strategies. The main outcomes are (i) new evidence supports a simple, scalable, and pragmatic population-based AF screening pathway; (ii) rhythm management is evolving from therapy aimed at improving symptoms to an integrated domain in the prevention of AF-related outcomes, especially in patients with recently diagnosed AF; (iii) improved characterization of atrial cardiomyopathy may help to identify patients in need for therapy; (iv) standardized assessment of cognitive function in patients with AF could lead to improvement in patient outcomes; and (v) artificial intelligence (AI) can support all of the above aims, but requires advanced interdisciplinary knowledge and collaboration as well as a better medico-legal framework. Implementation of new evidence-based approaches to AF screening and rhythm management can improve outcomes in patients with AF. Additional benefits are possible with further efforts to identify and target atrial cardiomyopathy and cognitive impairment, which can be facilitated by AI
Retinoic Acid Restores Adult Hippocampal Neurogenesis and Reverses Spatial Memory Deficit in Vitamin A Deprived Rats
A dysfunction of retinoid hippocampal signaling pathway has been involved in the appearance of affective and cognitive disorders. However, the underlying neurobiological mechanisms remain unknown. Hippocampal granule neurons are generated throughout life and are involved in emotion and memory. Here, we investigated the effects of vitamin A deficiency (VAD) on neurogenesis and memory and the ability of retinoic acid (RA) treatment to prevent VAD-induced impairments. Adult retinoid-deficient rats were generated by a vitamin A-free diet from weaning in order to allow a normal development. The effects of VAD and/or RA administration were examined on hippocampal neurogenesis, retinoid target genes such as neurotrophin receptors and spatial reference memory measured in the water maze. Long-term VAD decreased neurogenesis and led to memory deficits. More importantly, these effects were reversed by 4 weeks of RA treatment. These beneficial effects may be in part related to an up-regulation of retinoid-mediated molecular events, such as the expression of the neurotrophin receptor TrkA. We have demonstrated for the first time that the effect of vitamin A deficient diet on the level of hippoccampal neurogenesis is reversible and that RA treatment is important for the maintenance of the hippocampal plasticity and function
European Heart Rhythm Association (EHRA)/Heart Rhythm Society (HRS)/Asia Pacific Heart Rhythm Society (APHRS)/Latin American Heart Rhythm Society (LAHRS) expert consensus on risk assessment in cardiac arrhythmias: use the right tool for the right outcome, in the right population.
In clinical practice and for scientific purposes, cardiologists and primary care physicians perform risk assessment in patients with cardiac diseases or conditions with high risk of developing such. The European Heart Rhythm Association (EHRA), Heart Rhythm Society (HRS), Asia Pacific Heart Rhythm Society (APHRS), and the Latin American Heart Rhythm Society (LAHRS) set down this expert consensus statement task force to summarize the consensus regarding risk assessment in cardiac arrhythmias. Objectives were to raise awareness of using the right risk assessment tool for a given outcome in a given population, and to provide physicians with practical proposals that may lead to rational and evidence-based risk assessment and improvement of patient care in this regard. A large variety of methods are used for risk assessment and choosing the best methods and tools hereof in a given situation is not simple. Even though parameters and test results found associated with increased risk of one outcome (e.g. death) may also be associated with higher risk of other adverse outcomes, specific risk assessment strategies should be used only for the purposes for which they are validated. The work of this task force is summarized in a row of consensus statement tables
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