2,196 research outputs found
Polynomial Relations in the Centre of U_q(sl(N))
When the parameter of deformation q is a m-th root of unity, the centre of
U_q(sl(N))$ contains, besides the usual q-deformed Casimirs, a set of new
generators, which are basically the m-th powers of all the Cartan generators of
U_q(sl(N)). All these central elements are however not independent. In this
letter, generalising the well-known case of U_q(sl(2)), we explicitly write
polynomial relations satisfied by the generators of the centre. Application to
the parametrization of irreducible representations and to fusion rules are
sketched.Comment: 8 pages, minor TeXnical revision to allow automatic TeXin
Damage classification after the 2009 L'Aquila earthquake using multinomial logistic regression and neural networks
Post-earthquake surveys represent a fundamental tool for managing the emergency phase after a strong earthquake. In Italy, the evaluation of the post-earthquake functionality of ordinary buildings is based on the AeDES forms (Agibilitá e Danno nell'Emergenza Sismica, or equivalently, Rapid Post-Earthquake Damage evaluation forms). This form includes information on the building and records of the observed damage classified according to type and intensity in 60 subclasses. Based on the observed damage and expert judgment, the buildings are clustered into six risk classes, from A to F. The assigned class is used to calculate the maximum economic reimbursement owed for the reconstruction or repair of the building. However, often the cluster assignment is not entirely objective due to the inherent responsibility associated with a less conservative assessment. This paper uses the data from the 2009 L'Aquila earthquake to develop classification models based on multinomial logistic regression (MLR) and artificial neural networks (ANN) calibrated with data theoretically less influenced by personal biases. The proposed models, particularly the MLR, are intended to support the decision-making of the evaluation team in future updates of the AeDES forms. This approach cannot substitute expert evaluation, which is always necessary for complex scenarios but may mitigate the impact of subjectivity and can provide an indication of the expected outcome of the survey
Multibody parameter estimation: A comprehensive case-study for an innovative rear suspension
Numerical and virtual simulation of mechanical systems is a standard part of product development in the automotive sector, and multibody techniques are a consolidated tool to describe vehicle dynamics, elasto- kinematic behavior, handling, and comfort. To achieve high precision results as output of simulations, it is essential to provide the system with reliable data as input, and to accurately describe the vehicle and its subsystems. The task of gathering objective parameters to fully describe a vehicle can seem trivial to the stakeholders directly connected to a project, that can access detailed design data and a plethora of schemes and datasheets covering all subsystems of a vehicle. However, whenever this task regards benchmarking, prototyping, research projects or niche/low-volume products, data availability decreases drastically, and alternative forms of data acquisition become essential. This paper proposes a comprehensive overview of data gathering and experimental procedures used to reliably extract parameters of an existing vehicle using quick and accessible strategies. The analysis is based on a case-study project of an A-segment vehicle mounted with an innovative rear suspension scheme, whose behavior should be described by a dedicated elasto- kinematic multibody model as well as a full vehicle model for dynamic validation. The multibody model is based on Adams/Car with the inclusion of flexible elements, which is briefly described, while a closer focus is given to the experimental extraction of key features, such as: total mass, longitudinal and lateral position of the center of gravity, CoG height, wheel travel and wheel rate, shock-absorber damping coefficient, steering ratio, components inertia and flexible elements strain. The results obtained in the static and dynamic experimental validation suggest a good outcome from the methodology, that can be replicated on many kinds of vehicle modelling activities as an approachable and affordable experimental methodology for small projects
Genetic Variability Between Adapted Populations of Annual Ryegrass (\u3cem\u3eLolium Multiflorum\u3c/em\u3e Lam) In Argentina
Italian ryegrass (Lolium multiflorum Lam.) is one of the most important annual grasses used in Argentina because it adapts better to the intensive animal system of the Humid Pampas than other annual forage grass. Although much research has been done to study its productive potential and management technologies, little work has focused on breeding and selection. There is ample evidence that genetic variability occurs within grass species (Snaydon, 1987; Andrés and Barufaldi, 1997) both in morphology and physiology. As a result the variation of attributes related with yield potential, quality and adaptation to different management systems, is often used in plant breeding to develop new varieties. The objective of this work was to evaluate the genetic variability between 32 populations of annual ryegrass adapted to different grassland environments in the Humid Pampas Region of Argentina as an introductory part of a breeding programme at INTA. The final aim of this programme is to provide new varieties of annual ryegrass adapted to different management systems
Genomics knowledge and attitudes among European public health professionals. Results of a cross-sectional survey
Background The international public health (PH) community is debating the opportunity to incorporate genomic technologies into PH practice. A survey was conducted to assess attitudes of the European Public Health Association (EUPHA) members towards their role in the implementation of public health genomics (PHG), and their knowledge and attitudes towards genetic testing and the delivery of genetic services. Methods EUPHA members were invited via monthly newsletter and e-mail to take part in an online survey from February 2017 to January 2018. A descriptive analysis of knowledge and attitudes was conducted, along with a univariate and multivariate analysis of their determinants. Results Five hundred and two people completed the questionnaire, 17.9% were involved in PHG activities. Only 28.9% correctly identified all medical conditions for which there is (or not) evidence for implementing genetic testing; over 60% thought that investing in genomics may divert economic resources from social and environmental determinants of health. The majority agreed that PH professionals may play different roles in incorporating genomics into their activities. Better knowledge was associated with positive attitudes towards the use of genetic testing and the delivery of genetic services in PH (OR = 1.48; 95% CI 1.01–2.18). Conclusions Our study revealed quite positive attitudes, but also a need to increase awareness on genomics among European PH professionals. Those directly involved in PHG activities tend to have a more positive attitude and better knowledge; however, gaps are also evident in this group, suggesting the need to harmonize practice and encourage greater exchange of knowledge among professionals
Composition of Kinetic Momenta: The U_q(sl(2)) case
The tensor products of (restricted and unrestricted) finite dimensional
irreducible representations of \uq are considered for a root of unity.
They are decomposed into direct sums of irreducible and/or indecomposable
representations.Comment: 27 pages, harvmac and tables macros needed, minor TeXnical revision
to allow automatic TeXin
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