803 research outputs found
Self‐reported food and drug allergy in Maputo, Mozambique
Public Health. 2005 Jul;119(7):587-9.
Self-reported food and drug allergy in Maputo, Mozambique.
Lunet N, Falcão H, Sousa M, Bay N, Barros H.
SourceDepartment of Hygiene and Epidemiology, University of Porto Medical School, Portugal. [email protected]
PMID: 15925673 [PubMed - indexed for MEDLINE
Tuned liquid dampers simulation for earthquake response control of buildings
This paper is focused on the study of an earthquake protection system, the Tuned Liquid Damper (TLD), which
can, if adequately designed, reduce earthquake demands on buildings. This positive effect is accomplished taking
into account the oscillation of the free surface of a fluid inside a tank (sloshing). The behaviour of an isolated
Tuned Liquid Damper, subjected to a sinusoidal excitation at its base, with different displacement amplitudes,
was studied by finite element analysis. The efficiency of the TLD in improving the seismic response of an existing building, representative of modern architecture buildings in southern European countries was also evaluated based on linear dynamic analyses
Linking Clifford analysis and combinatorics through bijective methods
The application of Clifford Analysis methods in Combinatorics has some peculiarities due to the use of noncommutative algebras. But it seems natural to expect from here some new results different from those obtained by using approaches based on several complex variable. For instances, the fact that in Clifford Analysis the point-wise multiplication of monogenic functions as well as their composition are not algebraically closed in this class of generalized holomorphic functions causes serious problems. Indeed, this is one of the reasons why in polynomial approximation almost every problem needs the construction of specially adapted polynomial bases.
Our aim is to show that the analysis and comparison of different representations of the same polynomial or entire function allow to link Clifford Analysis
and Combinatorics by means of bijective methods.
In this context we also stress the central role of the hypercomplex derivative for power series representations in connection with the concept of Appell sequences as analytic tools for establishing this link.Fundação para a Ciência e a Tecnologia (FCT
3D-Mappings using monogenic functions
Conformal mappings of plane domains are realized by holomorphic functions with non vanishing derivative.
Therefore complex differentiability plays an important role in all questions related to fundamental properties of such mapping. In contrast to the planar case, in higher dimensions the set of conformal mappings consists only of M¨obius transformations. But unfortunately M¨obius transformations are not monogenic functions and therefore
also not hypercomplex differentiable. However the equivalence between both concepts - hypercomplex differentiability in the sense of [9], [11] and monogenicity - suggests the question whether monogenic functions can play or not a special role for other types of 3D-mappings, for instance, for quasi-conformal ones. Our goal is to present a case study of an approach to 3D-mappings by using particularly easy to handle monogenic homogeneous polynomials as basis for approximating the mapping function. Thereby we extend significantly the results obtained in [3]. From the numerical point of view we apply ideas from complex numerical analysis realizing the approximation via polynomials of a small real parameter
Special monogenic polynomials - properties and applications
AIP conference proceedings, vol. 936In Clifford Analysis several different methods have been developed for constructing monogenic functions as series with respect to properly chosen homogeneous monogenic polynomials. Almost all these methods rely on sets of orthogonal polynomials with their origin in classical (real) Harmonic Analysis in order to obtain the desired basis of homogeneous polynomials. We use a direct and elementary approach to this problem and construct a set of homogeneous polynomials involving only products of a hypercomplex variable and its hypercomplex conjugate. The obtained set is an Appell set of monogenic polynomials with respect to the hypercomplex derivative. Its intrinsic properties and some applications are presented.The research of the first author was partially supported by the R&D unit Matematica e Aplicacoes (UIMA) of the University of Aveiro, through the Portuguese Foundation for Science and Technology (FCT). The research of the second author was partially supported by the Portuguese Foundation for Science and Technology (FCT) through the research program POCTI
On paravector valued homogeneous monogenic polynomials with binomial expansion
The aim of this note is to study a set of paravector valued homogeneous monogenic polynomials that can be used for a construction of sequences of generalized Appell polynomials in the context of Clifford analysis. Therefore, we admit a general form of the vector part of the first degree polynomial in the Appell sequence. This approach is different from the one presented in recent papers on this subject. We show that in the case of paravector valued polynomials of three real variables, there exist essentially two different types of such polynomials together with two other trivial types of polynomials. The proof indicates a way of obtaining analogous results in the case of polynomials of more than three variables.Fundação para a Ciência e a Tecnologia (FCT
A note on a one-parameter family of non-symmetric number triangles
The recently growing interest in special Cliff ord Algebra valued polynomial solutions of generalized Cauchy-Riemann systems in (n + 1)-dimensional Euclidean spaces suggested
a detailed study of the arithmetical properties of their coe fficients, due to their combinatoric relevance. This concerns, in particular, a generalized Appell sequence of homogeneous polynomials whose coe cient's set can be treated as a one-parameter family of non-symmetric triangles of fractions. The discussion of its properties, similar to those
of the ordinary Pascal triangle (which itself does not belong to the family), is carried out in this paper.Fundação para a Ciência e a Tecnologia (FCT
Clifford analysis between continuous and discrete
Some decades ago D. Knuth et al. have coined concrete mathematics as the blending of CONtinuous and
disCRETE math, taking into account that problems of standard discrete mathematics can often be solved by
methods based on continuous mathematics together with a controlled manipulation of mathematical formulas.
Of course, it was not a new idea, but due to the ongoing emergence of computer aided algebraic manipulation
tools of that time it emphasized their use for elegant solutions of old problems or even the detection of new
important relationships. Our aim is to show that the same philosophy can be successfully applied to Clifford
Analysis by taking advantages of its inherent non-commutative algebra to obtain results or develop methods
that are di erent from other ones. In particular, we determine new binomial sums by using a hypercomplex
generating function for a special type of monogenic polynomials and develop an algorithm for the determination
of their scalar and vector part which illustrates well the diifferences to the corresponding complex case.The research of the first author was partially supported by the R&D Unit Matemdtica e Aplicagoes (UIMA) of the University of Aveiro, through the Portuguese Foundation for Science and Technology (FCT)
On special functions in the context of clifford analysis
Considering the foundation of Quaternionic Analysis by R. Fueter and his collaborators in the beginning of the
1930s as starting point of Clifford Analysis, we can look back to 80 years of work in this eld. However the
interest in multivariate analysis using Clifford algebras only started to grow significantly in the 70s. Since then
a great amount of papers on Clifford Analysis referring different classes of Special Functions have appeared.
This situation may have been triggered by a more systematic treatment of monogenic functions by their
multiple series development derived from Gegenbauer or associated Legendre polynomials (and not only by
their integral representation). Also approaches to Special Functions by means of algebraic methods, either
Lie algebras or through Lie groups and symmetric spaces gained by that time importance and infuenced their
treatment in Clifford Analysis. In our talk we will rely on the generalization of the classical approach to
Special Functions through differential equations with respect to the hypercomplex derivative, which is a more
recently developed tool in Clifford Analysis. In this context special attention will be payed to the role of Special
Functions as intermediator between continuous and discrete mathematics. This corresponds to a more recent
trend in combinatorics, since it has been revealed that many algebraic structures have hidden combinatorial
underpinnings.The research of the first author was partially supported by the Centro de Investigacao e Desenvolvimento em Matematica e Aplicacoes (CIDMA) of the University of Aveiro, through the Portuguese Foundation for Science and Technology (FCT)
Special functions versus elementary functions in hypercomplex function theory
In recent years special hypercomplex Appell polynomials
have been introduced by several authors and their main properties
have been studied by different methods and with different
objectives. Like in the classical theory of Appell polynomials, the
generating function of hypercomplex Appell polynomials is a
hypercomplex exponential function. The observation that this
generalized exponential function has, for example, a close
relationship with Bessel functions confirmed the practical
significance of investigation on special classes of hypercomplex
differentiable functions. Its usefulness for combinatorial studies
has also been investigated. Moreover, an extension of those ideas
led to the construction of complete sets of hypercomplex Appell
polynomial sequences. Here we show how this opens the way for a more
systematic study of the relation between some classes of Special
Functions and Elementary Functions in Hypercomplex Function Theory.FC
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