University of Madeira

About: University of Madeira is a education organization based out in Funchal, Portugal. It is known for research contribution in the topics: Population & Dendrimer. The organization has 1014 authors who have published 2759 publications receiving 59457 citations.

Intersection Local Times of Independent Fractional Brownian Motions as Generalized White Noise Functionals

Abstract: In this work we present expansions of intersection local times of fractional Brownian motions in ? d , for any dimension d?1, with arbitrary Hurst coefficients in (0,1) d . The expansions are in terms of Wick powers of white noises (corresponding to multiple Wiener integrals), being well-defined in the sense of generalized white noise functionals. As an application of our approach, a sufficient condition on d for the existence of intersection local times in L 2 is derived, extending the results in Nualart and Ortiz-Latorre (J. Theoret. Probab. 20(4):759---767, 2007) to different and more general Hurst coefficients.

Occurrence of flat bands in strongly correlated Fermi systems and high- T c superconductivity of electron-doped compounds

Abstract: We consider a class of strongly correlated Fermi systems that exhibit an interaction-induced flat band pinned to the Fermi surface, and generalize the Landau strategy to accommodate a flat band and apply the more comprehensive theory to electron systems of solids. The non-Fermi-liquid behavior that emerges is compared with relevant experimental data on heavy-fermion metals and electron-doped high-T c compounds. We elucidate how heavy-fermion metals have extremely low superconducting transition temperature T c , its maximum reached in the heavy-fermion metal CeCoIn5 does not exceed 2.3 K, and explain the enhancement of T c observed in high-T c superconductors. We show that the coefficient A 1 of the T-linear resistivity scales with T c , in agreement with the experimental behavior uncovered in the electron-doped materials. We have also constructed schematic temperature-doping phase diagram of the copper oxide superconductor La2 − x Ce x CuO4 and explained the doping dependence of its resistivity.

Homocysteine Metabolism in Children and Adolescents: Influence of Age on Plasma Biomarkers and Correspondent Genotype Interactions

Abstract: Background: Imbalance of homocysteine (Hcy) metabolism links with several pathologies; nevertheless, it is poorly characterized in pediatric populations. This study investigated the impact of age on plasma concentrations of Hcy and relevant biomarkers along with correspondent genotype interactions. Methods: A healthy pediatric cohort aged 9 (n = 195) and 17 (n = 128) years old (yo) was studied. Immunoassays and GC-MS-SIM-mode quantified plasma levels of Hcy and biomarkers. PCR-RFLP or quantitative-PCR assays assessed common variations in related genes. Results: Age impacted on levels of Hcy and metabolic markers: older children presented with the lowest folates and total-cobalamin (tCbl), while with the highest Hcy concentrations, whereas methylmalonic acid (MMA) and holotranscobalamin (Holo-TC) levels remained similar in 9-yo and 17-yo children. The relationships between B-vitamins and metabolic markers were also dependent on age. Only in the older children, MMA correlated with tCbl and Holo-TC, and MMA levels were markedly higher in the 17-yo subjects presenting with the lowest quartiles of Holo-TC concentrations. Lastly, age also impacted on the correlations between genotype and biomarkers. In the 17-yo group, however not in the 9-yo children, tHcy differed between MTHFR 677 genotypes, with subjects who had the MTHFR 677TT genotype displaying the highest tHcy concentrations. Conclusions: Age impacts on the Hcy metabolism dynamics in a pediatric population.

Making model-based UI design practical: usable and open methods and tools

Abstract: Model-based IU is an established discipline. However, it has not been adopted in the software industry with the initial expected success, and it has been kept in the meanwhile in the academia. The main aim of this workshop is to analyze the current problems with model-based UI design approaches and envision the main characteristics and challenges to solve in the next generation of model-based UI tools.

Adaptive Reduced-Bias Tail Index and VaR Estimation via the Bootstrap Methodology

Abstract: In this article, we deal with the estimation, under a semi-parametric framework, of a positive extreme value index γ, the primary parameter in Statistics of Extremes, and associated estimation of the Value at Risk (VaR) at a level p, the size of the loss occurred with a small probability p. We consider second-order minimum-variance reduced-bias (MVRB) estimators, and propose the use of bootstrap computer-intensive methods for the adaptive choice of thresholds, both for γ and Var p . Applications in the fields of insurance and finance, as well as a small-scale simulation study of the bootstrap adaptive estimators’ behaviour, are also provided.