3,733 research outputs found
Forward-Backward and Charge Asymmetries in the Standard Model
This talk reviews the Standard Model predictions for the top-quark forward
backward and charge asymmetries measured at the Tevatron and at the LHC.Comment: 8 pages, 2 figures. Proceedings of CKM 2012, the 7th International
Workshop on the CKM Unitarity Triangle, University of Cincinnati, USA, 28
September - 2 October 201
Numerical Loop-Tree Duality: contour deformation and subtraction
We introduce a novel construction of a contour deformation within the
framework of Loop-Tree Duality for the numerical computation of loop integrals
featuring threshold singularities in momentum space. The functional form of our
contour deformation automatically satisfies all constraints without the need
for fine-tuning. We demonstrate that our construction is systematic and
efficient by applying it to more than 100 examples of finite scalar integrals
featuring up to six loops. We also showcase a first step towards handling
non-integrable singularities by applying our work to one-loop infrared
divergent scalar integrals and to the one-loop amplitude for the ordered
production of two and three photons. This requires the combination of our
contour deformation with local counterterms that regulate soft, collinear and
ultraviolet divergences. This work is an important step towards computing
higher-order corrections to relevant scattering cross-sections in a fully
numerical fashion.Comment: 87 page
MayDay: VestAndPage Workshop Concept, Theory and Practice
Considerations on how VestAndPage facilitate a workshop on Performance art.
Text published in: "How We Teach Performance Art: University Courses and Workshop Syllabus", Edited by Valentin Torrens. Outskirts Press, July 2014.
The book offers 42 different approaches to transmit the generative source of creativity in live action by internationally experienced practitioners, teachers and theorists of performance art from 21 countries. 340 pages full of ideas, points of view, methodologies, sensitivities, exercises and proposals to enjoy live practice with deeper involvement immersion, knowledge and study. The book begins with a clarification of the terms used to name this practice and continues with the cultural introductions previously to the appearance of the performance as an artistic differentiated activity. To see the performance's creative nature and its relation with the game; its communicative qualities and his perception. It's followed by a report on previous books and publications related to the pedagogies of the performance. Later, a description of education affiliations, inside the pedagogic common tendencies of performance courses. An approach to courses and workshop's characteristics. It's begun with the syllabus and the comments of the university courses and continues with the workshops. Some teachers have sent a text on their relation to the performance; in those cases, it's placed before the description of the syllabus, in order to complement, from the subjective intimacy, our best comprehension of his work and his course. After the entire syllabus, there is a small biographical summary of the authors and bibliography on performance
DISTRIBUTION OF PIGMENT CELLS IN THE HEART OF THE RABBITFISH, CHIMAERA MONSTROSA (CONDRICHTHYES: HOLOCEPHALI)
El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013. Anatomical Record, Volume 296, Special Feature — 1: P-076.The study of extracutaneous cells producing and storing melanin is of interest because it
may provide valuable information about the presence of neural crest elements in internal
organs and tissues. Here we report, for the first time, the presence and distribution of
melanophores in the heart of a chondrichthyan species, the rabbitfish, Chimaera
monstrosa. Pigment cells were found in all of 20 hearts examined. Pigment cells occur
mainly in the cardiac outflow tract, which consists of two anatomical components, the
proximal, myocardial conus arteriosus and the distal, non-myocardial bulbus arteriosus.
A few groups of dark pigmented cells were found in the apex of the ventricle of one
specimen and in the atrium of two specimens. In all instances, the melanophores were
located in the subepicardial space, where they could be well recognized in both
unstained and stained histological sections. The distribution and intensity of the
pigmentation in the cardiac outflow tract varies markedly between individuals. In all
cases, however, the pigmented area is larger on the dorsal than on the ventral surface.
Dorsally, the size of the pigmented area ranges from a fringe that includes the bulbus
and the distal part of the conus to the whole surface of the outflow tract. Ventrally, the
pigmented area does not cover the entire conus arteriosus. The intensity of the
pigmentation also varies widely; in general, it is highest at the distal portion of the conus.
There is no relationship between the distribution and intensity of the pigmentation and
the sex and age of the animals. The functional role of the pigmented cells is unknown. If
the melanophores in the heart of C. monstrosa are indeed of neural crest origin, it would
suggest a notable contribution of the neural crest cells to the cardiac outflow tract in
holocephalans.Proyecto CGL2010-16417/BOS; Fondos FEDER
BES-2011-04690
The bulbus arteriosus of the holocephalan heart
El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013.Anatomical Record, Volume 296, Special Feature — 1: P-074.Previous work has shown that the outflow tract of the elasmobranch heart, namely the
cardiac portion intercalated between the ventricle and the ventral aorta, does not consist
of a single component, the conus arteriosus, as has classically been assumed, but two,
the myocardial conus arteriosus and the non-myocardial bulbus arteriosus. From the
evolutionary perspective, knowledge of the anatomy of the cardiac outflow tract of the
holocephali is important, as they are the sister group of elasmobranchs. Our aim is to
describe the cardiac outflow tract of four holocephalan species, two of them, Chimaera
monstrosa and Hydrolagus affinis of the family Chimaeridae, and the other two, Harriotta
raleighana and Rhinochimaera atlantica, of the family Rhinochimaeridae. The cardiac
outflow tract of the four species consisted of a myocardial conus arteriosus, furnished
with valves, and a bulbus arteriosus devoid of cardiac muscle. Both the bulbus and
conus are tubular in shape. The length of the bulbus relative to the total length of the
outflow tract is somewhat smaller in the rhinochimaerids (15%-19%) than in the
chimaerids (19%-23%). The bulbus is covered by epicardium and is crossed by the main
coronary artery trunks. Histologically, the bulbus is mainly composed of elastin and
collagen, and, to a lesser extent, by smooth muscle. This suggests that in
holocephalans, the bulbus actively helps to protect the gill vasculature from exposure to
high-pressure pulses of blood. Our results prove that the bulbus arteriosus is common to
chondrichthyans. In addition, they support the hypothesis that the cardiac outflow tract
consisted of a conus arteriosus and a bulbus arteriosus from the beginning of the jawed
vertebrate radiation, contributing to our understanding of the morphological changes that
have occurred at the arterial pole of the heart in both actinopterygians and
sarcopterygians.Proyecto CGL2010-16417/BOS; Fondos FEDE
Local Unitarity: a representation of differential cross-sections that is locally free of infrared singularities at any order
We propose a novel representation of differential scattering cross-sections
that locally realises the direct cancellation of infrared singularities
exhibited by its so-called real-emission and virtual degrees of freedom. We
take advantage of the Loop-Tree Duality representation of each individual
forward-scattering diagram and we prove that the ensuing expression is locally
free of infrared divergences, applies at any perturbative order and for any
process without initial-state collinear singularities. Divergences for loop
momenta with large magnitudes are regulated using local ultraviolet
counterterms that reproduce the usual Lagrangian renormalisation procedure of
quantum field theories. Our representation is especially suited for a numerical
implementation and we demonstrate its practical potential by computing fully
numerically and without any IR counterterm the next-to-leading order accurate
differential cross-section for the process . We
also show first results beyond next-to-leading order by computing interference
terms part of the N4LO-accurate inclusive cross-section of a
scalar scattering process.Comment: 88 page
Prevalence of Dog Erythrocyte Antigen 1 in 7, 414 Dogs in Italy
The study aim was to establish the prevalence of DEA 1, the most immunogenic and clinically important blood group in canine
blood transfusion, in 7,414 dogs from Italy. The potential sensitization risk following a first transfusion and the acute reaction
risk following a second transfusion given without a cross-matching and blood typing test were also calculated. Dogs tested were
purebred (4,798) and mongrel (2,616); 38.8% were DEA 1 negative and 61.2% were DEA 1 positive. High prevalence for DEA 1
positive blood type was found in Ariegeois and English Setter, whereas German Shepherd and Boxer had higher DEA 1 negative
blood type. Breeds with blood type never reported before included French Brittany Spaniel and Pug showing a high prevalence
of DEA 1 positive type, while French Bulldog and West Highland White Terrier were more often DEA 1 negative. Just 48.8% of
purebred and 13.9% of mongrel dogs were considered as prospective blood donors based upon their blood type.Most of the breeds
had a sensitization risk of 20.0–25.0%. Rottweiler and Ariegeois had less risk of sensitization (9.4 and 4.2%) and the minor risk of
an acute transfusional reaction (0.9–0.2%).The prevalence of DEA 1 positive and negative dogs in Italy agrees withmost of the data
already reported in the literature
Optimal Variance Control of the Score Function Gradient Estimator for Importance Weighted Bounds
This paper introduces novel results for the score function gradient estimator
of the importance weighted variational bound (IWAE). We prove that in the limit
of large (number of importance samples) one can choose the control variate
such that the Signal-to-Noise ratio (SNR) of the estimator grows as .
This is in contrast to the standard pathwise gradient estimator where the SNR
decreases as . Based on our theoretical findings we develop a novel
control variate that extends on VIMCO. Empirically, for the training of both
continuous and discrete generative models, the proposed method yields superior
variance reduction, resulting in an SNR for IWAE that increases with
without relying on the reparameterization trick. The novel estimator is
competitive with state-of-the-art reparameterization-free gradient estimators
such as Reweighted Wake-Sleep (RWS) and the thermodynamic variational objective
(TVO) when training generative models
A reduced-order model for segregated fluid-structure interaction solvers based on an ALE approach
This article presents a Galerkin projection model order reduction approach
for fluid-structure interaction (FSI) problems in the Finite Volume context.
The reduced-order model (ROM) is based on proper orthogonal decomposition
(POD), where a reduced basis is formed using energy-dominant POD modes. The
reduced basis also consists of characteristics of the POD time modes derived
from the POD time modes coefficients. In addition, the solution state vector
comprises the mesh deformation, considering the structural motion in FSI. The
results are obtained by applying the proposed method to time-dependent problems
governed by the 2D incompressible Navier-Stokes equations. The main objective
of this work is to introduce a hybrid technique mixing up the classical
Galerkin-projection approach with a data-driven method to obtain a versatile
and accurate algorithm for resolving FSI problems with moving meshes. The
effectiveness of this approach is demonstrated in the case study of
vortex-induced vibrations (VIV) of a cylinder at Reynolds number Re = 200. The
results show the stability and accuracy of the proposed method with respect to
the high-dimensional model by capturing transient flow fields and, more
importantly, the forces acting on the moving objects
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