1,528 research outputs found
Free field realizations of certain modules for affine Lie algebra slˆ(n,C)
For the affine Lie algebra slˆ(n,C) we study a realization in terms of infinite sums of partial differential operators of a family of representations introduced in [BBFK]. These representations generalize a construction of Imaginary Verma modules [F1]. The realization constructed in the paper extends the free field realization of Imaginary Verma modules constructed by B.Cox [С1]
Guest editorial: Performance measurement in supply chains during disruptions: lessons from the COVID-19 pandemic
String Imprints from a Pre-inflationary Era
We derive the equations governing the dynamics of cosmic strings in a flat
anisotropic universe of Bianchi type I and study the evolution of simple cosmic
string loop solutions. We show that the anisotropy of the background can have a
characteristic effect in the loop motion. We discuss some cosmological
consequences of these findings and, by extrapolating our results to cosmic
string networks, we comment on their ability to survive an inflationary epoch,
and hence be a possible fossil remnant (still visible today) of an anisotropic
phase in the very early universe.Comment: 5 pages, 3 figure
Photoionization and photofragmentation of singly charged positive and negative Sc3 N@ C80 endohedral fullerene ions
Effects of proportional assisted ventilation on exercise performance in idiopathic pulmonary fibrosis patients
SummaryBackgroundPatients with idiopathic pulmonary fibrosis (IPF) present an important ventilatory limitation reducing their exercise capacity. Non-invasive ventilatory support has been shown to improve exercise capacity in patients with obstructive diseases; however, its effect on IPF patients remains unknown.ObjectiveThe present study assessed the effect of ventilatory support using proportional assist ventilation (PAV) on exercise capacity in patients with IPF.MethodsTen patients (61.2±9.2 year-old) were submitted to a cardiopulmonary exercise testing, plethysmography and three submaximal exercise tests (60% of maximum load): without ventilatory support, with continuous positive airway pressure (CPAP) and PAV. Submaximal tests were performed randomly and exercise capacity, cardiovascular and ventilatory response as well as breathlessness subjective perception were evaluated. Lactate plasmatic levels were obtained before and after submaximal exercise.ResultsOur data show that patients presented a limited exercise capacity (9.7±3.8mLO2/kg/min). Submaximal test was increased in patients with PAV compared with CPAP and without ventilatory support (respectively, 11.1±8.8min, 5.6±4.7 and 4.5±3.8min; p<0.05). An improved arterial oxygenation and lower subjective perception to effort was also observed in patients with IPF when exercise was performed with PAV (p<0.05). IPF patients performing submaximal exercise with PAV also presented a lower heart rate during exercise, although systolic and diastolic pressures were not different among submaximal tests. Our results suggest that PAV can increase exercise tolerance and decrease dyspnoea and cardiac effort in patients with idiopathic pulmonary fibrosis
Influencia de la irrigación en el atizonamiento de las hojas de ñame (Dioscorea cayennensis) por Curvularia eragrostidis en el N.E. de Brasil
El atizonmiento de las hojas(quema), causado por Curvularia eragrostidis, es una de las principales enfermedades del ñame (Dioscorea cayennensis) en elnoreste brasilero. Por esto se analizó el progreso y patrón espacial de la enfermedad en cuatro áreas con plantaciones comerciales de ñame, dos irrigadas (A y B ) y dos no irrigadas (Cy D), localizadas en ell municipio deAlianca, Estado de Pernambuco, Brasil.En las áreas irrigadas, la cantidad inicial y la máxima severidad de la enfermedad, fueron superiores a las verificadas en las áreas no irrigadas. Utilizando el modelo de Gompertz, no se verificaron diferencias significativas entre las tasas de progreso de la enfermedad, siendo idénticas en las áreas A, B, C y ligeramente inferior en el área D. Los valores de área bajo la curva de progreso de la enfermedad fueron superiores en las áreas irrigadas, aunque con pequeña diferencia a lo constatado en el área D. En las áreas B, C y D, las plantas enfermas presentaron un patrón aleatorio, dentro y entre las lineas de plantación y el área A presentó un patrón agregado, especialmente entre las lineas.Considerando estos resultados, es posible concluir que la irrigación no tuvo influencia significativa en la severidad de la mancha necrótica de las hojas deñame ni en la agregación de plantas enfermas dentro de las áreas de plantación
Technical and economic pre-feasibility study for the construction of septic tank-filter-sinkhole with alternative material
Received: February 2nd, 2021 ; Accepted: August 3rd, 2021 ; Published: August 24th, 2021 ; Correspondence: [email protected] study of the different materials used in the construction of septic tanks aims to
facilitate and spread the use of this sewage treatment system in places that are not assisted by
municipal sewage systems and in the rural area, which despite having a smaller number of
inhabitants compared to the urban area This study aims to carry out a technical and economic
evaluation of the concrete and tires using in the construction of septic tanks-filter-sinkhole. The
wastewater treatment systems were built according to the recommendations in NBR 7229/93 and
13969/97. To evaluate the efficiency of each system built, the following parameters were
analyzed: chemical oxygen demand (COD), the potential of hydrogen (pH), alkalinity, acidity,
and temperature. In the economic evaluation, the materials and labor required to install the
systems were considered using the Brazilian cost database (SINAPI), and an economic and
financial feasibility study was carried out. According to the technical and economic analysis of
construction, both systems showed the same technical performance, however, the concrete design
proved to be more advantageous than the tire design, considering the difficulty in acquiring the
tires and the high cost if it is necessary to buy them, in addition to the greater difficulty in handling
and installing the tire system compared to the concrete one
Measuring in the Early Universe: CMB Temperature, Large-Scale Structure and Fisher Matrix Analysis
We extend our recent work on the effects of a time-varying fine-structure
constant in the cosmic microwave background, by providing a thorough
analysis of the degeneracies between and the other cosmological
parameters, and discussing ways to break these with both existing and/or
forthcoming data. In particular, we present the state-of-the-art CMB
constraints on , through a combined analysis of the BOOMERanG, MAXIMA
and DASI datasets. We also present a novel discussion of the constraints on
coming from large-scale structure observations, focusing in particular
on the power spectrum from the 2dF survey. Our results are consistent with no
variation in from the epoch of recombination to the present day, and
restrict any such (relative) variation to be less than about 4%. We show that
the forthcoming MAP and (particularly) Planck experiments will be able to break
most of the currently existing degeneracies between and other
parameters, and measure to better than percent accuracy.Comment: 11 pages in RevTex4 format. Low-quality figures to comply with arXiv
restrictions (better ones available from the authors). v2: Updated Oklo
discussion, plus other cosmetic changes. Version to appear in Phys Rev
Review of AdS/CFT Integrability, Chapter III.2: Exact world-sheet S-matrix
We review the derivation of the S-matrix for planar N=4 supersymmetric
Yang-Mills theory and type IIB superstring theory on an AdS5xS5 background.
After deriving the S-matrix for the su(2) and su(3) sectors at the one-loop
level based on coordinate Bethe ansatz, we show how su(2|2) symmetry leads to
the exact asymptotic S-matrix up to an overall scalar function. We then briefly
review the spectrum of bound states by relating these states to simple poles of
the S-matrix. Finally, we review the derivation of the asymptotic Bethe
equations, which can be used to determine the asymptotic multiparticle
spectrum.Comment: 20 pages, see also overview article arXiv:1012.3982, v2: references
to other chapters updated, v3: references added and minor change
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