42 research outputs found
Weight-finite modules over the quantum affine and double quantum affine algebras of type
We define the categories of weight-finite modules over the type quantum affine algebra and over the
type double quantum affine algebra
that we introduced in a previous paper. In
both cases, we classify the simple objects in those categories. In the quantum
affine case, we prove that they coincide with the simple finite-dimensional
-modules which were classified by Chari and
Pressley in terms of their highest (rational and -dominant)
-weights or, equivalently, by their Drinfel'd polynomials. In the double
quantum affine case, we show that simple weight-finite modules are classified
by their (-dominant) highest -weight spaces, a family of simple modules
over the subalgebra of
which is conjecturally isomorphic to a
split extension of the elliptic Hall algebra. The proof of the classification,
in the double quantum affine case, relies on the construction of a double
quantum affine analogue of the evaluation modules that appear in the quantum
affine setting.Comment: 46 page
Self-gravitating branes of codimension 4 in Lovelock gravity
We construct a familly of exact solutions of Lovelock equations describing
codimension four branes with discrete symmetry in the transverse space. Unlike
what is known from pure Einstein gravity, where such brane solutions of higher
codimension are singular, the solutions we find, for the complete Lovelock
theory, only present removable singularities. The latter account for a
localised tension-like energy-momentum tensor on the brane, in analogy with the
case of a codimension two self-gravitating cosmic string in pure Einstein
gravity. However, the solutions we discuss present two main distinctive
features : the tension of the brane receives corrections from the induced
curvature of the brane's worldsheet and, in a given Lovelock theory, the
spectrum of possible values of the tension is discrete. These solutions provide
a new framework for the study of higher codimension braneworlds.Comment: 22 page
Fermenting Feminism
"Fermenting Feminism brings together artists whose work responds to what it means to bring fermentation and feminism into the same critical space. These are works that approach fermentation through intersectional and trans-inclusive feminist frameworks, and works that approach feminisms through the metaphor and material practice of fermentation. As both a metaphor and a physical process, fermentation embodies bioavailability and accessibility, preservation and transformation, inter-species symbiosis and coevolution, biodiversity and futurity, harm reduction and care." -- p. [1]
Fluid hydration to prevent post-ERCP pancreatitis in average- to high-risk patients receiving prophylactic rectal NSAIDs (FLUYT trial): Study protocol for a randomized controlled trial
Background: Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is the most common complication of ERCP and may run a severe course. Evidence suggests that vigorous periprocedural hydration can prevent PEP, but studies to date have significant methodological drawbacks. Importantly, evidence for its added value in patients already receiving prophylactic rectal non-steroidal anti-inflammatory drugs (NSAIDs) is lacking and the cost-effectiveness of the approach has not been investigated. We hypothesize that combination therapy of rectal NSAIDs and periprocedural hydration would significantly lower the incidence of post-ERCP pancreatitis compared to rectal NSAIDs alone in moderate- to high-risk patients undergoing ERCP. Methods: The FLUYT trial is a multicenter, parallel group, open label, superiority randomized controlled trial. A total of 826 moderate- to high-risk patients undergoing ERCP that receive prophylactic rectal NSAIDs will be randomized to a control group (no fluids or normal saline with a maximum of 1.5 mL/kg/h and 3 L/24 h) or intervention group (lactated Ringer's solution with 20 mL/kg over 60 min at start of ERCP, followed by 3 mL/kg/h for 8 h thereafter). The primary endpoint is the incidence of post-ERCP pancreatitis. Secondary endpoints include PEP severity, hydration-related complications, and cost-effectiveness. Discussion: The FLUYT trial design, including hydration schedule, fluid type, and sample size, maximize its power of identifying a potential difference in post-ERCP pancreatitis incidence in patients receiving prophylactic rectal NSAIDs
Isovector excitations in Nb-100 and their decays by neutron emission studied via the Mo-100(t, He-3 + n) reaction at 115 MeV/u
Spin–isospin excitations in Nb100 were studied via the Mo100(t,He3) charge-exchange reaction at 115 MeV/u with the goal to constrain theoretical models used to describe the isovector spin response of nuclei. The experiment was performed with a secondary beam of tritons, and 3He particles were analyzed in the S800 magnetic spectrometer. Decay by neutron emission from excited states in Nb100 was observed by using plastic and liquid scintillator arrays. Differential cross sections were analyzed and monopole excitations were revealed by using a multipole decomposition analysis. The Gamow–Teller transition strength observed at low excitation energies, which is important for estimating the electron-capture rate in astrophysical scenarios, was strongly fragmented and reduced compared to single-particle and spherical mean-field models. The consideration of deformation in the theoretical estimates was found to be important to better describe the fragmentation and strengths. A strong excitation of the isovector spin giant monopole resonance was observed, and well reproduced by the mean-field models. Its presence makes the extraction of Gamow–Teller strengths at high excitation energies difficult. The branches for statistical and direct decay by neutron emission were identified in the spectra. The upper limit for the branching ratio by direct decay (integrated over all observed excitations) was determined to be 20±6%. Even though the statistical uncertainties in the neutron-coincident data were too large to perform detailed studies of the decay by neutron emission from individual states and resonances, the experiment demonstrates the feasibility of the method
Birkhoff's theorem in Lovelock gravity
We show that the generic solutions of the Lovelock equations with spherical, planar or hyperbolic symmetry are locally isometric to the corresponding static Lovelock black hole. As a consequence, these solutions are locally static: they admit an additional Killing vector that can either be space-like or time-like, depending on the position. This result also holds in the presence of an abelian gauge field, in which case the solutions are locally isometric to a charged static black hole
On double quantum affinization: 1. Type
We define the double quantum affinization of type as a topological Hopf algebra. We prove that it admits a subalgebra whose completion is (bicontinuously) isomorphic to the completion of the quantum toroidal algebra , defined as the (simple) quantum affinization of the untwisted affine Kac-Moody Lie algebra of type , equipped with a certain topology inherited from its natural -grading. The isomorphism is constructed by means of a bicontinuous action by automorphisms of an affinized version -- technically a split extension by the coweight lattice -- of the affine braid group of type on that completion of . It can be regarded as an affinized version of the Damiani-Beck isomorphism, familiar from the quantum affine setting. We eventually prove the corresponding triangular decomposition of and briefly discuss the consequences regarding the representation theory of quantum toroidal algebras