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• Mathematical model that predicts the behavior of a novel seismic isolation device. • Validation of the model with results of cyclic quasi-static tests with axial load. • Numerical simulations and verify the benefit of using the isolation device developed. Base isolation is an efficient strategy for protecting structures, especially in countries with high seismic risk, such as Chile. This paper presents the conceptual model, mathematical model, experimental validation and numerical analysis of a roller type base isolation device that aims to solve problems of limited tensile strength (compared to its compressive strength) and lateral instability of all types of rubber bearing isolators when faced with elevated axial load. The conceptual model describes the device's components and operation. The mathematical model establishes its constitutive law based on the equilibrium equations formulated considering large lateral displacements. Experimental tests were run on a shake-table with a load frame to simulate the isolator's interaction with the superstructure, considering a combination of the device's design parameters, in order to identify their effect. In the numerical analysis, six simple frame buildings were modelled and subjected to a seismic record using the proposed roller isolator. Error parameters were obtained between the numerical predictions and the experimental results in each loading and unloading cycle, varying between 1.6% and 5.1% for dissipated energy and 4.0% to 17.7% for the magnitude of force. The proposed device worked as a seismic isolator, reducing the structure's response in a magnitude order in relation to the building fixed on its base. [ABSTRACT FROM AUTHOR]

Abstract: Jujuy is a province of Argentina, placed in the extreme northwest of the country, close to the borders with Chile, Bolivia and the Salta province of Argentina. Different studies on South American population have proposed that actual population is composed by Native American maternal lineages and European paternal lineages with different proportions among regions. The principal aim of this work is to study the mitochondrial genetic variability of the Jujuy population and also the different contributions of European and American-Native settlers. Results showed that the population sample was mainly composed by Native American haplogroups. Genetic contribution of European origin is very low. Haplogroups distribution in the province of Jujuy was related to other neighboring Native American populations. These preliminary data could be helpful for understanding the present distribution of the mitochondrial DNA haplogroups in this region. [Copyright &y& Elsevier]

Ancient mtDNA was successfully recovered from 24 skeletal samples of a total of 60 ancient individuals from Patagonia-Tierra del Fuego, dated to 100-400 years BP, for which consistent amplifications and two-strand sequences were obtained. Y-chromosome STRs (DYS434, DYS437, DYS439, DYS393, DYS391, DYS390, DYS19, DYS389I, DYS389II, and DYS388) and the biallelic system DYS199 were also amplified, Y-STR alleles could be characterized in nine cases, with an average of 4.1 loci per sample correctly typed. In two samples of the same ethnic group (Aonikenk), an identical and complete eight-loci haplotype was recovered. The DYS199 biallelic system was used as a control of contamination by modern DNA and, along with DYS19, as a marker of American origin. The analysis of both mtDNA and Y-STRs revealed DNA from Amerindian ancestry. The observed polymorphisms are consistent with the hypothesis that the ancient Fuegians are close to populations from south-central Chile and Argentina, but their high nucleotide diversity and the frequency of single lineages strongly support early genetic differentiation of the Fuegians through combined processes of population bottleneck, isolation, and/or migration, followed by strong genetic drift. This suggests an early genetic diversification of the Fuegians right after their arrival at the southernmost extreme of South America., (Copyright 2003 Wiley-Liss, Inc.)