601 research outputs found
Superspace formulation of general massive gauge theories and geometric interpretation of mass-dependent BRST symmetries
A superspace formulation is proposed for the osp(1,2)-covariant Lagrangian
quantization of general massive gauge theories. The superalgebra os0(1,2) is
considered as subalgebra of sl(1,2); the latter may be considered as the
algebra of generators of the conformal group in a superspace with two
anticommuting coordinates. The mass-dependent (anti)BRST symmetries of proper
solutions of the quantum master equations in the osp(1,2)-covariant formalism
are realized in that superspace as invariance under translations combined with
mass-dependent special conformal transformations. The Sp(2) symmetry - in
particular the ghost number conservation - and the "new ghost number"
conservation are realized as invariance under symplectic rotations and
dilatations, respectively. The transformations of the gauge fields - and of the
full set of necessarily required (anti)ghost and auxiliary fields - under the
superalgebra sl(1,2) are determined both for irreducible and first-stage
reducible theories with closed gauge algebra.Comment: 35 pages, AMSTEX, precision of reference
Global Anomalies in the Batalin Vilkovisky Quantization
The Batalin Vilkovisky (BV) quantization provides a general procedure for
calculating anomalies associated to gauge symmetries. Recent results show that
even higher loop order contributions can be calculated by introducing an
appropriate regularization-renormalization scheme. However, in its standard
form, the BV quantization is not sensible to quantum violations of the
classical conservation of Noether currents, the so called global anomalies. We
show here that the BV field antifield method can be extended in such a way that
the Ward identities involving divergencies of global Abelian currents can be
calculated from the generating functional, a result that would not be obtained
by just associating constant ghosts to global symmetries. This extension,
consisting of trivially gauging the global Abelian symmetries, poses no extra
obstruction to the solution of the master equation, as it happens in the case
of gauge anomalies. We illustrate the procedure with the axial model and also
calculating the Adler Bell Jackiw anomaly.Comment: We emphasized the fact that our procedure only works for the case of
Abelian global anomalies. Section 3 was rewritten and some references were
added. 12 pages, LATEX. Revised version that will appear in Phys. Rev.
Field-enlarging transformations and chiral theories
A field-enlarging transformation in the chiral electrodynamics is performed.
This introduces an additional gauge symmetry to the model that is unitary and
anomaly-free and allows for comparison of different models discussed in the
literature. The problem of superfluous degrees of freedom and their influence
on quantization is discussed. Several "mysteries" are explained from this point
of view.Comment: 14 pages, LaTeX-file, BI-TP 93/0
Triplectic Quantization of W2 gravity
The role of one loop order corrections in the triplectic quantization is
discussed in the case of W2 theory. This model illustrates the presence of
anomalies and Wess Zumino terms in this quantization scheme where extended BRST
invariance is represented in a completely anticanonical form.Comment: 10 pages, no figure
The effects of melatonin versus placebo on delirium in hip fracture patients: study protocol of a randomised, placebo-controlled, double blind trial
<p>Abstract</p> <p>Background</p> <p>With an ageing population, older persons become a larger part of the hospital population. The incidence of delirium is high in this group, and experiencing delirium has major short- and long-term sequelae, which makes prevention crucial. During delirium, a disruption of the sleep-wake cycle is frequently observed. Melatonin plays an important role in the regulation of the sleep-wake cycle, so this raised the hypothesis that alterations in the metabolism of melatonin might play an important role in the development of delirium. The aim of this article is to describe the design of a randomised, placebo controlled double-blind trial that is currently in progress and that investigates the effects of melatonin versus placebo on delirium in older, postoperative hip fracture patients.</p> <p>Methods/Design</p> <p>Acutely hospitalised patients aged 65 years or older admitted for surgical repair of hip fracture are randomised (n = 452) into a treatment or placebo group. Prophylactic treatment consists of orally administered melatonin (3 mg) at 21:00 h on five consecutive days. The primary outcome is the occurrence of delirium, to be diagnosed according to the Confusion Assessment Method, within eight days after start of the study medication. Secondary outcomes are delirium severity, measured by the Delirium Rating Scale; duration of delirium; differences in subtypes of delirium; differences in total length of hospital stay; total dose of antipsychotics and/or benzodiazepine use during delirium; and in-hospital complications. In the twelve-month follow up visit, cognitive function is measured by a Mini-Mental state examination and the Informant Questionnaire on Cognitive Decline in the Elderly. Functional status is assessed with the Katz ADL index score (patient and family version) and grip strength measurement. The outcomes of these assessments are compared to the outcomes that were obtained during admission.</p> <p>Discussion</p> <p>The proposed study will contribute to our knowledge because studies on the prophylactic treatment of delirium with long term follow up remain scarce. The results may lead to a prophylactic treatment for frail older persons at high risk for delirium that is safe, effective, and easily implementable in daily practice.</p> <p>Trial registration</p> <p>Dutch Clinical Trial Registry: <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1576">NTR1576</a></p
A pilot study of rivastigmine in the treatment of delirium after stroke: A safe alternative
<p>Abstract</p> <p>Background</p> <p>Delirium is a common disorder in the early phase of stroke. Given the presumed cholinergic deficiency in delirium, we tested treatment with the acetylcholinesterase inhibitor rivastigmine.</p> <p>Methods</p> <p>This pilot study was performed within an epidemiological study. In 527 consecutive stroke patients presence of delirium was assessed during the first week with the confusion assessment method. Severity was scored with the delirium rating scale (DRS). Sixty-two patients developed a delirium in the acute phase of stroke. Only patients with a severe and persistent delirium (defined as a DRS of 12 or more for more than 24 hours) were enrolled in the present study. In total 26 fulfilled these criteria of whom 17 were treated with orally administered rivastigmine with a total dose between 3 and 12 mg a day. Eight patients could not be treated because of dysphagia and one because of early discharge.</p> <p>Results</p> <p>No major side effects were recorded. In 16 patients there was a considerable decrease in severity of delirium. The mean DRS declined from 14.8 on day one to 8.5 after therapy and 5.6 after tapering. The mean duration of delirium was 6.7 days (range; 2–17).</p> <p>Conclusion</p> <p>Rivastigmine is safe in stroke patients with delirium even after rapid titration. In the majority of patients the delirium improved after treatment. A randomized controlled trial is needed to establish the usefulness of rivastigmine in delirium after stroke.</p> <p>Trial registration</p> <p>Nederlands Trial Register NTR1395</p
Batalin-Vilkovisky formalism in perturbative algebraic quantum field theory
On the basis of a thorough discussion of the Batalin-Vilkovisky formalism for
classical field theory presented in our previous publication, we construct in
this paper the Batalin-Vilkovisky complex in perturbatively renormalized
quantum field theory. The crucial technical ingredient is a proof that the
renormalized time-ordered product is equivalent to the pointwise product of
classical field theory. The renormalized Batalin-Vilkovisky algebra is then the
classical algebra but written in terms of the time-ordered product, together
with an operator which replaces the ill defined graded Laplacian of the
unrenormalized theory. We identify it with the anomaly term of the anomalous
Master Ward Identity of Brennecke and D\"utsch. Contrary to other approaches we
do not refer to the path integral formalism and do not need to use
regularizations in intermediate steps.Comment: 34 page
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