19 research outputs found
Integrable degenerate -models from 4d Chern-Simons theory
We present a general construction of integrable degenerate -models on a 2d manifold using the formalism of Costello and
Yamazaki based on 4d Chern-Simons theory on . We
begin with a physically motivated review of the mathematical results of
[arXiv:2008.01829] where a unifying 2d action was obtained from 4d Chern-Simons
theory which depends on a pair of 2d fields and on
subject to a constraint and with depending rationally on the
complex coordinate on . When the meromorphic 1-form
entering the action of 4d Chern-Simons theory is required to have a double pole
at infinity, the constraint between and was solved in
[arXiv:2011.13809] to obtain integrable non-degenerate -models. We
extend the latter approach to the most general setting of an arbitrary 1-form
and obtain integrable degenerate -models. To illustrate
the procedure we reproduce two well known examples of integrable degenerate
-models: the pseudo dual of the principal chiral model and the
bi-Yang-Baxter -model
A new example of the effects of a singular background on the zeta function
Para motivar nuestra discusión, consideramos un campo escalar dimensional 1 + 1 que interactúa con un fondo estático de tipo Coulomb, de modo que el espectro de fluctuaciones cuánticas está dado por un operador diferencial de segundo orden en una sola coordenada r con un coeficiente singular proporcional a 1 / r . Encontramos que las funciones espectrales de este operador presentan un comportamiento interesante: la función ζ tiene múltiples polos en el plano complejo; en consecuencia, aparecen logaritmos del tiempo adecuado en la expansión de trazas de calor. Como consecuencia, la función ζ no proporciona una regularización finita de la acción efectiva. Este trabajo amplÃa resultados similares previamente derivados en el contexto de singularidades cónicas.Fil: Falomir, Horacio Alberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de FÃsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FÃsica La Plata; ArgentinaFil: Liniado, Joaquin. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de FÃsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FÃsica La Plata; ArgentinaFil: González Pisani, Pablo Andrés. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de FÃsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FÃsica La Plata; Argentin
Integrable Deformations from Twistor Space
Integrable field theories in two dimensions are known to originate as defect
theories of 4d Chern-Simons and as symmetry reductions of the 4d anti-self-dual
Yang-Mills equations. Based on ideas of Costello, it has been proposed in work
of Bittleston and Skinner that these two approaches can be unified starting
from holomorphic Chern-Simons in 6 dimensions. We provide the first complete
description of this diamond of integrable theories for a family of deformed
sigma models, going beyond the Dirichlet boundary conditions that have been
considered thus far. Starting from 6d holomorphic Chern-Simons theory on
twistor space with a particular meromorphic 3-form , we construct the
defect theory to find a novel 4d integrable field theory, whose equations of
motion can be recast as the 4d anti-self-dual Yang-Mills equations. Symmetry
reducing, we find a multi-parameter 2d integrable model, which specialises to
the -deformation at a certain point in parameter space. The same model
is recovered by first symmetry reducing, to give 4d Chern-Simons with
generalised boundary conditions, and then constructing the defect theory.Comment: 38 pages, 1 figur
Social protection to the informal sector: the role of minimum wage and income transfer policies
The objective of this study is to examine the impact that changes in minimum wage and the main income transfer programs have had on the economic participation of the population and the informal sector in Argentina. The obtained evidence suggests that modifications to minimum wage did not produce adverse effects on employment or have a substantial impact on the probabilities of entering the informal sector. Regarding the income transfers, it was possible to confirm that it did not encourage adults in beneficiary households to become economically inactive
Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease
Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
Algebraic Structure of Dirac Hamiltonians in Non-Commutative Phase Space
In this article we study two-dimensional Dirac Hamiltonians with
non-commutativity both in coordinates and momenta from an algebraic
perspective. In order to do so, we consider the graded Lie algebra
generated by Hermitian bilinear forms in the
non-commutative dynamical variables and the Dirac matrices in dimensions.
By further defining a total angular momentum operator, we are able to express a
class of Dirac Hamiltonians completely in terms of these operators. In this
way, we analyze the energy spectrum of some simple models by constructing and
studying the representation spaces of the unitary irreducible representations
of the graded Lie algebra . As
application of our results, we consider the Landau model and a fermion in a
finite cylindrical well.Comment: 22 page
Car culture and countryside change
SIGLEAvailable from British Library Document Supply Centre-DSC:96/09701 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
The National Trust Centenary Conference Proceedings
Conference held in Manchester (GB), 25-28 Sep 1995SIGLEAvailable from British Library Document Supply Centre- DSC:q96/00261 / BLDSC - British Library Document Supply CentreGBUnited Kingdo