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Publications

Publications by LIAAD

2005

Rigidity of hyperbolic sets on surfaces

Authors
Pinto, AA; Rand, DA;

Publication
JOURNAL OF THE LONDON MATHEMATICAL SOCIETY-SECOND SERIES

Abstract
Given a hyperbolic invariant set of a diffeomorphism on a surface, it is proved that, if the holonomies are sufficiently smooth, then the diffeomorphism on the hyperbolic invariant set is rigid in the sense that it is C1+ conjugate to a hyperbolic affine model.

2005

Discordancy test for the bipolar Watson distribution defined on the hypersphere

Authors
Figueiredo, A; Gomes, P;

Publication
COMMUNICATIONS IN STATISTICS-SIMULATION AND COMPUTATION

Abstract
As the Watson distribution is much used for modeling axial data, it is important to investigate the existence of a possible outlier in samples from this distribution. So, we generalize to the hypersphere a test of discordancy of an outlier or several outliers en bloc available for the Watson distribution defined on the sphere. We also evaluate the performance of the test for some cases with the usual types of alternatives.

2005

Identification of monoclonal proteins in serum: A comparison of acetate, agarose gel and capillary electrophoresis

Authors
Guimaraes, C; Ramalho, R; Ramos, J; Marinho, A; Oliveira, B; Caudeias, J;

Publication
CLINICA CHIMICA ACTA

Abstract

2005

Laboratory evaluation of proteinuria in patients with multiple myeloma: The value of different parameters

Authors
Guimaraes, C; Ramalho, R; Ramos, J; Marinho, A; Oliveira, B; Candeias, J;

Publication
CLINICA CHIMICA ACTA

Abstract

2005

Effect of social desirability on dietary intake estimated from a food frequency questionnaire [Influência da desejabilidade social na estimativa da ingestão alimentar obtida através de um questionário de frequência de consumo alimentar]

Authors
Barros, R; Moreira, P; Oliveira, B;

Publication
Acta Medica Portuguesa

Abstract
Introduction: Self-report of dietary intake could be biased by social desirability thus affecting risk estimates in epidemiological studies. The objective of this study was to assess the effect of social desirability on dietary intake estimated from a food frequency questionnaire (FFQ). Methods: A convenience sample of 483 Portuguese university students was recruited. Subjects were invited to complete a two-part self-administered questionnaire: the first part included the Marlowe-Crowne Social Desirability Scale (M-CSDS), a physical activity questionnaire and self-reported height and weight; the second part, included a semi-quantitative FFQ validated for Portuguese adults, that should be returned after fulfilment. All subjects completed the first part of the questionnaire and 40.4% returned the FFQ fairly completed. Results: In multiple regression analysis, after adjustment for energy and confounders, social desirability produced a significant positive effect in the estimates of dietary fibre, vitamin C, vitamin E, magnesium and potassium, in both genders. In multiple regression, after adjustment for energy and confounders, social desirability had a significant positive effect in the estimates of vegetable consumption, for both genders, and a negative effect in white bread and beer, for women. Conclusion: Social desirability affected nutritional and food intake estimated from a food frequency questionnaire.

2005

Improved lower bounds for the early/tardy scheduling problem with no idle time

Authors
Valente, JMS; Alves, RAFS;

Publication
JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY

Abstract
In this paper, we consider the single machine earliness/tardiness scheduling problem with no idle time. Two of the lower bounds previously developed for this problem are based on Lagrangean relaxation and the multiplier adjustment method, and require an initial sequence. We investigate the sensitivity of the lower bounds to the initial sequence, and experiment with different dispatch rules and some dominance conditions. The computational results show that it is possible to obtain improved lower bounds by using a better initial sequence. The lower bounds are also incorporated in a branch-and-bound algorithm, and the computational tests show that one of the new lower bounds has the best performance for larger instances.

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