612 research outputs found
Massive and massless higher spinning particles in odd dimensions
We study actions for massive bosonic particles of higher spins by
dimensionally reducing an action for massless particles. For the latter we take
a model with a SO(N) extended local supersymmetry on the worldline, that is
known to describe massless (conformal) particles of higher spins in flat
spacetimes of even dimensions. Dimensional reduction produces an action for
massive spinning particles in odd dimensions. The field equations that emerge
in a quantization a la Dirac are shown to be equivalent to the Fierz-Pauli
ones. The massless limit generates a multiplet of massless states with higher
spins, whose first quantized field equations have a geometric form with fields
belonging to various types of Young tableaux. These geometric equations can be
partially integrated to show their equivalence with the standard
Fronsdal-Labastida equations. We covariantize our model to check whether an
extension to curved spacetimes can be achieved. Restricting to (A)dS spaces, we
find that the worldline gauge algebra becomes nonlinear, but remains first
class. This guarantees consistency on such backgrounds. A light cone analysis
confirms the presence of the expected propagating degrees of freedom. A
covariant analysis is worked out explicitly for the massive case, which is seen
to give rise to the Fierz-Pauli equations extended to (A)dS spaces. It is worth
noting that in D=3 the massless limit of our model when N goes to infinity has
the same field content of the Vasiliev's theory that accommodates each spin
exactly once.Comment: 31 page
Particles with non abelian charges
Efficient methods for describing non abelian charges in worldline approaches
to QFT are useful to simplify calculations and address structural properties,
as for example color/kinematics relations. Here we analyze in detail a method
for treating arbitrary non abelian charges. We use Grassmann variables to take
into account color degrees of freedom, which however are known to produce
reducible representations of the color group. Then we couple them to a U(1)
gauge field defined on the worldline, together with a Chern-Simons term, to
achieve projection on an irreducible representation. Upon gauge fixing there
remains a modulus, an angle parametrizing the U(1) Wilson loop, whose
dependence is taken into account exactly in the propagator of the Grassmann
variables. We test the method in simple examples, the scalar and spin 1/2
contribution to the gluon self energy, and suggest that it might simplify the
analysis of more involved amplitudes.Comment: 14 page
Use of Medicinal Cannabis and Synthetic Cannabinoids in Posttraumatic Stress Disorder (PTSD): a systematic review
Background and Objectives: Post-traumatic stress disorder (PTSD) is a common psychiatric disorder resulting from a traumatic event, is manifested through hyperarousal, anxiety, depressive symptoms, and sleep disturbances. Despite several therapeutic approaches being available, both pharmacological and psychological, recently a growing interest has developed in using cannabis and synthetic cannabinoids stems from their consideration as more efficient and better tolerated alternatives for the treatment of this condition. The present paper aims to evaluate the clinical and therapeutic potentials of medical cannabis and synthetic cannabinoids in treating PTSD patients. Methods: A systematic electronic search was performed, including all papers published up to May 2019, using the following keywords (((cannabis[Title/Abstract]) OR (synthetic cannabinoids [Title/Abstract])) AND ((PTSD[Title/Abstract]) OR (Posttraumatic stress disorder[Title/Abstract]))) for the topics ‘Cannabis’, ‘Synthetic Cannabinoids’, ‘PTSD’, and MESH terms, on the PubMed, Cochrane Library, and Web of Science online databases. For data gathering purposes, PRISMA guidelines were followed. Results were organized into two groups, considering cannabis and synthetic cannabinoids as different therapeutic approaches for PTSD. Results: Present data show that cannabis and synthetic cannabinoids, both acting on the endocannabinoids system, may have a potential therapeutic use for improving PTSD symptoms, e.g., reducing anxiety, modulating memory-related processes, and improving sleep. Conclusions: Even though the current literature suggests that cannabis and synthetic cannabinoids may have a role in the treatment of PTSD, there is currently limited evidence regarding their safety and efficacy. Therefore, additional research is needed in order to better understand the effectiveness and therapeutic usage of these drug classes and monitor their safety.Peer reviewe
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The ω-3 fatty acids for Prevention of Post-Operative Atrial Fibrillation trial—rationale and design
Postoperative atrial fibrillation/flutter (PoAF) commonly complicates cardiac surgery, occurring in 25% to 60% of patients. Postoperative atrial fibrillation/flutter is associated with significant morbidity, higher long-term mortality, and increased health care costs. Novel preventive therapies are clearly needed. In experiments and short-term trials, seafood-derived long-chain ω-3 polyunsaturated fatty acids (PUFAs) influence several risk factors that might reduce risk of PoAF. A few small and generally underpowered trials have evaluated effects of ω-3-PUFAs supplementation on PoAF with mixed results. The OPERA trial is an appropriately powered, investigator-initiated, randomized, double-blind, placebo-controlled, multinational trial to determine whether perioperative oral ω-3-PUFAs reduces occurrence of PoAF in patients undergoing cardiac surgery. Additional aims include evaluation of resource use, biologic pathways and mechanisms, postoperative cognitive decline, and safety. Broad inclusion criteria encompass a “real-world” population of outpatients and inpatients scheduled for cardiac surgery. Treatment comprises a total preoperative loading dose of 8 to 10 g of ω-3-PUFAs or placebo divided over 2 to 5 days, followed by 2 g/d until hospital discharge or postoperative day 10, whichever comes first. Based on anticipated 30% event rate in controls, total enrollment of 1,516 patients (758 per treatment arm) will provide 90% power to detect 25% reduction in PoAF. The OPERA trial will provide invaluable evidence to inform biologic pathways; proof of concept that ω-3-PUFAs influence cardiac arrhythmias; and potential regulatory standards and clinical use of this simple, inexpensive, and low-risk intervention to prevent PoAF
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Plasma Phospholipid Omega‐3 Fatty Acids and Incidence of Postoperative Atrial Fibrillation in the OPERA Trial
Background: Long‐chain polyunsaturated omega‐3 fatty acids (n‐3 PUFA) demonstrated antiarrhythmic potential in experimental studies. In a large multinational randomized trial (OPERA), perioperative fish oil supplementation did not reduce the risk of postoperative atrial fibrillation (PoAF) in cardiac surgery patients. However, whether presupplementation habitual plasma phospholipid n‐3 PUFA, or achieved or change in n‐3 PUFA level postsupplementation are associated with lower risk of PoAF is unknown. Methods and Results: In 564 subjects undergoing cardiac surgery between August 2010 and June 2012 in 28 centers across 3 countries, plasma phospholipid levels of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) were measured at enrollment and again on the morning of cardiac surgery following fish oil or placebo supplementation (10 g over 3 to 5 days, or 8 g over 2 days). The primary endpoint was incident PoAF lasting ≥30 seconds, centrally adjudicated, and confirmed by rhythm strip or ECG. Secondary endpoints included sustained (≥1 hour), symptomatic, or treated PoAF; the time to first PoAF; and the number of PoAF episodes per patient. PoAF outcomes were assessed until hospital discharge or postoperative day 10, whichever occurred first. Relative to the baseline, fish oil supplementation increased phospholipid concentrations of EPA (+142%), DPA (+13%), and DHA (+22%) (P<0.001 each). Substantial interindividual variability was observed for change in total n‐3 PUFA (range=−0.7% to 7.5% after 5 days of supplementation). Neither individual nor total circulating n‐3 PUFA levels at enrollment, morning of surgery, or change between these time points were associated with risk of PoAF. The multivariable‐adjusted OR (95% CI) across increasing quartiles of total n‐3 PUFA at enrollment were 1.0, 1.06 (0.60 to 1.90), 1.35 (0.76 to 2.38), and 1.19 (0.64 to 2.20); and for changes in n‐3 PUFA between enrollment and the morning of surgery were 1.0, 0.78 (0.44 to 1.39), 0.89 (0.51 to 1.55), and 1.01 (0.58 to 1.75). In stratified analysis, demographic, medication, and cardiac parameters did not significantly modify these associations. Findings were similar for secondary PoAF endpoints. Conclusions: Among patients undergoing cardiac surgery, neither higher habitual circulating n‐3 PUFA levels, nor achieved levels or changes following short‐term fish oil supplementation are associated with risk of PoAF. Clinical Trial Registration URL: Clinicaltrials.gov Unique identifier: NCT0097048
ANMCO/ELAS/SIBioC Consensus Document: Biomarkers in heart failure
Biomarkers have dramatically impacted the way heart failure (HF) patients are evaluated and managed. A biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biological or pathogenic processes, or pharmacological responses to a therapeutic intervention. Natriuretic peptides [B-type natriuretic peptide (BNP) and N-terminal proBNP] are the gold standard biomarkers in determining the diagnosis and prognosis of HF, and a natriuretic peptide-guided HF management looks promising. In the last few years, an array of additional biomarkers has emerged, each reflecting different pathophysiological processes in the development and progression of HF: myocardial insult, inflammation, fibrosis, and remodelling, but their role in the clinical care of the patient is still partially defined and more studies are needed before to be well validated. Moreover, several new biomarkers have the potential to identify patients with early renal dysfunction and appear to have promise to help the management cardio-renal syndrome. With different biomarkers reflecting HF presence, the various pathways involved in its progression, as well as identifying unique treatment options for HF management, a closer cardiologist-laboratory link, with a multi-biomarker approach to the HF patient, is not far ahead, allowing the unique opportunity for specifically tailoring care to the individual pathological phenotype
Spinning particles and higher spin field equations
Relativistic particles with higher spin can be described in first quantization using actions with local supersymmetry on the worldline. First, we present a brief review of these actions and their use in first quantization. In a Dirac quantization scheme the field equations emerge as Dirac constraints on the Hilbert space, and we outline how they lead to the description of higher spin fields in terms of the more standard Fronsdal-Labastida equations. Then, we describe how these actions can be extended so that the propagating particle is allowed to take different values of the spin, i.e. carry a reducible representation of the Poincar ́e group. This way one may identify a four dimensional model that carries the same degrees of freedom of the minimal Vasiliev’s interacting higher spin field theory. Extensions to massive particles and to propagation on (A)dS spaces are also briefly commented upon
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