14 research outputs found
On electromagnetic interactions for massive mixed symmetry field
In this paper we investigate electromagnetic interactions for simplest
massive mixed symmetry field. Using frame-like gauge invariant formulation we
extend Fradkin-Vasiliev procedure, initially proposed for investigation of
gravitational interactions for massless particles in AdS space, to the case of
electromagnetic interactions for massive particles leaving in (A)dS space with
arbitrary value of cosmological constant including flat Minkowski space. At
first, as an illustration of general procedure, we re-derive our previous
results on massive spin 2 electromagnetic interactions and then we apply this
procedure to massive mixed symmetry field. These two cases are just the
simplest representatives of two general class of fields, namely completely
symmetric and mixed symmetry ones, and it is clear that the results obtained
admit straightforward generalization to higher spins as well.Comment: 17 pages. Some clarifications added. Version to appear in JHE
Spin 3 cubic vertices in a frame-like formalism
Till now most of the results on interaction vertices for massless higher spin
fields were obtained in a metric-like formalism using completely symmetric
(spin-)tensors. In this, the Lagrangians turn out to be very complicated and
the main reason is that the higher the spin one want to consider the more
derivatives one has to introduce. In this paper we show that such
investigations can be greatly simplified if one works in a frame-like
formalism. As an illustration we consider massless spin 3 particle and
reconstruct a number of vertices describing its interactions with lower spin 2,
1 and 0 ones. In all cases considered we give explicit expressions for the
Lagrangians and gauge transformations and check that the algebra of gauge
transformations is indeed closed.Comment: 17 pades, no figure
Gauge fields in (A)dS within the unfolded approach: algebraic aspects
It has recently been shown that generalized connections of the (A)dS space
symmetry algebra provide an effective geometric and algebraic framework for all
types of gauge fields in (A)dS, both for massless and partially-massless. The
equations of motion are equipped with a nilpotent operator called
whose cohomology groups correspond to the dynamically relevant quantities like
differential gauge parameters, dynamical fields, gauge invariant field
equations, Bianchi identities etc. In the paper the -cohomology is
computed for all gauge theories of this type and the field-theoretical
interpretation is discussed. In the simplest cases the -cohomology is
equivalent to the ordinary Lie algebra cohomology.Comment: 59 pages, replaced with revised verio
Ordinary-derivative formulation of conformal totally symmetric arbitrary spin bosonic fields
Conformal totally symmetric arbitrary spin bosonic fields in flat space-time
of even dimension greater than or equal to four are studied. Second-derivative
(ordinary-derivative) formulation for such fields is developed. We obtain gauge
invariant Lagrangian and the corresponding gauge transformations. Gauge
symmetries are realized by involving the Stueckelberg and auxiliary fields.
Realization of global conformal boost symmetries on conformal gauge fields is
obtained. Modified de Donder gauge condition and de Donder-Stueckelberg gauge
condition are introduced. Using the de Donder-Stueckelberg gauge frame,
equivalence of the ordinary-derivative and higher-derivative approaches is
demonstrated. On-shell degrees of freedom of the arbitrary spin conformal field
are analyzed. Ordinary-derivative light-cone gauge Lagrangian of conformal
fields is also presented. Interrelations between the ordinary-derivative gauge
invariant formulation of conformal fields and the gauge invariant formulation
of massive fields are discussed.Comment: 51 pages, v2: Results and conclusions of v1 unchanged. In Sec.3,
brief review of higher-derivative approaches added. In Sec.4, new
representations for Lagrangian, modified de Donder gauge, and de
Donder-Stueckelberg gauge added. In Sec.5, discussion of interrelations
between the ordinary-derivative and higher-derivative approaches added.
Appendices A,B,C,D and references adde
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
The Optimize Heart Failure Care Program: Initial lessons from global implementation
Hospitalization for heart failure (HF) places a major burden on healthcare services worldwide, and is a strong predictor of increased mortality especially in the first three months after discharge. Though undesirable, hospitalization is an opportunity to optimize HF therapy and advise clinicians and patients about the importance of continued adherence to HF medication and regular monitoring. The Optimize Heart Failure Care Program (www.optimize-hf.com), which has been implemented in 45 countries, is designed to improve outcomes following HF hospitalization through inexpensive initiatives to improve prescription of appropriate drug therapies, patient education and engagement, and post-discharge planning. It includes best practice clinical protocols for local adaptation, pre- and post-discharge checklists, and ‘My HF Passport’, a printed and smart phone application to improve patient understanding of HF and encourage involvement in care and treatment adherence. Early experience of the Program suggests that factors leading to successful implementation include support from HF specialists or ‘local leaders’, regular educational meetings for participating healthcare professionals, multidisciplinary collaboration, and full integration of pre- and post-hospital discharge checklists across care services. The Program is helping to raise awareness of HF and generate useful data on current practice. It is showing how good evidence-based care can be achieved through the use of simple clinician and patient-focused tools. Preliminary results suggest that optimization of HF pharmacological therapy is achievable through the Program, with little new investment. Further data collection will lead to a greater understanding of the impact of the Program on HF care and key indicators of success
Optimization of heart rate lowering therapy in hospitalized patients with heart failure: Insights from the Optimize Heart Failure Care Program
Background Hospitalization is an opportunity to optimize heart failure (HF) therapy. As optimal treatment for hospitalized HF patients in sinus rhythm with heart rate ≥ 70 bpm is unclear, we investigated the impact of combined beta-blocker (BB) and ivabradine versus BBs alone on short and longer term mortality and rehospitalization. Methods and results A retrospective analysis was performed on 370 hospitalized HF patients with heart rate ≥ 70 bpm (150 BB + ivabradine, 220 BB alone) in the Optimize Heart Failure Care Program in Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Russia, Ukraine, and Uzbekistan, from October 2015 to April 2016. Results At 1 month, 3 months, 6 months and 12 months, there were fewer deaths, HF hospitalizations and overall hospitalizations in patients on BB + ivabradine vs BBs alone. At 12 months, all-cause mortality or HF hospitalization was significantly lower with BB + ivabradine than BBs (adjusted hazard ratio [HR] 0.45 (95% confidence interval [CI] 0.32–0.64, P < 0.0001). Significantly greater improvement was seen in quality of life (QOL) from admission to 12 months with BB + ivabradine vs BBs alone (P = 0.0001). With BB + ivabradine, significantly more patients achieved ≥ 50% target doses of BBs at 12 months than on admission (82.0% vs 66.6%, P = 0.0001), but the effect was non-significant with BBs alone. Conclusions Heart rate lowering therapy with BB + ivabradine started in hospitalized HF patients (heart rate ≥ 70 bpm) is associated with reduced overall mortality and re-hospitalization over the subsequent 12 months. A prospective randomized trial is needed to confirm the advantages of this strategy