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The dynamic response of modern slender footbridges is usually sensitive to both the pedestrian actions and the uncertainties associated with their inherent structural behavior. Thus, tuned mass dampers have been widely integrated in the design of these structures to guarantee the fulfillment of the vibration serviceability limit state during their overall life cycle. Three different techniques of tuned mass dampers (active, semi-active and passive) are usually considered for this purpose. Although there are algorithms for the robust design of each particular technique, however, this specificity makes difficult the implementation of all these techniques in practical en gineering applications. Herein, the motion-based design method under uncertainty conditions is proposed and further implemented to create a common framework for the robust design of all these techniques when they are employed to mitigate pedestrian-induced vibrations in slender footbridges. According to this method, the design problem may be transformed into the combination of two sequential sub-problems: (i) a reliability multi objective optimization sub-problem; and (ii) a decision-making sub-problem. Subsequently, the performance of this proposal has been validated through a numerical case study in which the dynamic response of a steel footbridge has been controlled by three different tuned mass damper techniques designed according to the proposed common framework.

Dynamic and experimental analysis of structures are two of the most abstract and complex disciplines in structural engineering, because of its awkward mathematical and physical background and due to the multidisciplinary knowledge needed to go over the whole analysis (from the acquisition of measures up to the final interpretation of results). In particular, Fourier analysis (frequency domain analysis) in discrete time, which is routinely used in the dynamic analysis, is not usually well-understood and even is not well computed in discrete time. Frequently, students lose motivation trying to decrypt difficult mathematical developments, which do not let them to interpret properly complex concepts which are extremely important for current analysis in discrete time such as: Fourier transforms, aliasing, leakage, filtering, windowing, etc. For this reason, the authors has implemented a new teaching tools based on the numerical experiments and interactive learning that transform the learning experience into a more pleasant process than in the pass. In this way, recently-developed tools as “MATLAB Live Editor” allows professors to create interactive lecture notes, which students can easily follow, modify and simultaneously run during classes, developing its own intuitive interpretation of the knowledge. This tool is been successfully employing to teach dynamic analysis of structures in frequency domain with excellent feedback from the students., El análisis experimental y dinámico de estructuras son dos de las disciplinas más complejas y abstractas de la ingeniería estructural debido a la complejidad de los fundamentos que se manejan y al conocimiento multidisciplinar necesario para llevar a cabo el proceso completo de análisis (desde la toma de datos hasta la interpretación final de los resultados). En particular, el análisis de Fourier (análisis en el dominio de la frecuencia), el cual se usa continuamente en el análisis dinámico, no siempre se entiende adecuadamente e incluso no se aplica correctamente en el dominio discreto. Con frecuencia los estudiantes pierden la motivación intentando comprender los desarrollos matemáticos asociados, lo que no les permite interpretar adecuadamente conceptos más complejos y a la vez importantes como: la transformada de Fourier, “aliasing”, “leakage”, filtrado, ventanas de ponderación, etc. Por ello, los autores han implementado una nueva herramienta basada en la experimentación numérica y en el aprendizaje interactivo, haciendo del mismo un proceso más llevadero que en el pasado. Así, herramientas recientes como “MATLAB live Editor” permiten que los profesores creen clases interactivas que los estudiantes pueden de forma sencilla, seguir, modificar y ejecutar durante las clases, desarrollando un conocimiento más intuitivo del problema. Los autores están empleando esta herramienta exitosamente en el análisis dinámico de estructuras en el dominio de la frecuencia con muy buenos comentarios por parte de los estudiantes.

Several iron-related parameters have been reported to show significant heritability, and thus, seemed to be genetically regulated. A genome wide family-based study revealed two regions that showed a linkage signal with transferrin receptor levels. The aim of the study was to identify genetic markers associated with iron status biomarkers. Ten SNPs selected from the literature were tested, and parameters related to iron metabolism were analysed, in a group (n=284) of Spanish women. Data were analyzed using Bayesian Model Averaging (BMA) test and decision trees. The rs1375515, located in an intronic region of the calcium channel gene CACNA2D3, showed strong associations with levels of mean corpuscular volume according to BMA test, and with levels of haemoglobin and ferritin according to decision trees. The allele G was associated to low levels of these parameters which suggests higher iron deficiency anaemia risk. This SNP along with the C282Y mutation explained significant differences in the distribution of individuals in three iron-related clinical phenotypes (normal, iron deficient and iron deficiency anaemic). In conclusion, the rs1375515, or other genetic polymorphisms in linkage, may play important roles in iron status, probably by affecting the function of a calcium channel. These findings may be useful for further investigation in the etiology of iron diseases. © 2013 - IOS Press and the authors. All rights reserved.

Background: Iron deficiency anaemia is a worldwide health problem in which environmental, physiologic and genetic factors play important roles. The associations between iron status biomarkers and single nucleotide polymorphisms (SNPs) known to be related to iron metabolism were studied in menstruating women. Methods. A group of 270 Caucasian menstruating women, a population group at risk of iron deficiency anaemia, participated in the study. Haematological and biochemical parameters were analysed and 10 selected SNPs were genotyped by minisequencing assay. The associations between genetic and biochemical data were analysed by Bayesian Model Averaging (BMA) test and decision trees. Dietary intake of a representative subgroup of these volunteers (n = 141) was assessed, and the relationship between nutrients and iron biomarkers was also determined by linear regression. Results: Four variants, two in the transferrin gene (rs3811647, rs1799852) and two in the HFE gene (C282Y, H63D), explain 35% of the genetic variation or heritability of serum transferrin in menstruating women. The minor allele of rs3811647 was associated with higher serum transferrin levels and lower transferrin saturation, while the minor alleles of rs1799852 and the C282Y and H63D mutations of HFE were associated with lower serum transferrin levels. No association between nutrient intake and iron biomarkers was found. Conclusions: In contrast to dietary intake, these four SNPs are strongly associated with serum transferrin. Carriers of the minor allele of rs3811647 present a reduction in iron transport to tissues, which might indicate higher iron deficiency anaemia risk, although the simultaneous presence of the minor allele of rs1799852 and HFE mutations appear to have compensatory effects. Therefore, it is suggested that these genetic variants might potentially be used as markers of iron deficiency anaemia risk. © 2011 Blanco-Rojo et al; licensee BioMed Central Ltd.

An investigation into fine-scale European population structure was carried out using high-density genetic variation on nearly 6000 individuals originating from across Europe. The individuals were collected as control samples and were genotyped with more than 300 000 SNPs in genome-wide association studies using the Illumina Infinium platform. A major East-West gradient from Russian (Moscow) samples to Spanish samples was identified as the first principal component (PC) of the genetic diversity. The second PC identified a North-South gradient from Norway and Sweden to Romania and Spain. Variation of frequencies at markers in three separate genomic regions, surrounding LCT, HLA and HERC2, were strongly associated with this gradient. The next 18 PCs also accounted for a significant proportion of genetic diversity observed in the sample. We present a method to predict the ethnic origin of samples by comparing the sample genotypes with those from a reference set of samples of known origin. These predictions can be performed using just summary information on the known samples, and individual genotype data are not required. We discuss issues raised by these data and analyses for association studies including the matching of case-only cohorts to appropriate pre-collected control samples for genome-wide association studies.

En las cumbres de Sierra Nevada aparecen depósitos de morfologia acordonada que están constituidos por acumulaciones de cantos angulosos de gran tamaño y una pequeña o nula proporción en matriz. Estos han sido interpretados como depósitos de glaciares rocosos, generados en una última crisis climatica acontecida entre los 13.000 y 10.000 años B.P, Among the variety of deposits in the high mountain zone of Sierra Nevada, some coarse-grained detritic acumulations are worthy to remark. These appear related to glacial scarps and have been interpreted as ancien rock glaciers deposits. Two types have been distinguished: the first has a string-like morfology, the matrix is very scarce and hollow can be found between the pebbles; the second tends to show lobulate forms and higher contents of matrix. In both cases the pebbles are extremely angular and heterometric. The mechanism which probably originated these depositional forms has been gravitational displacing of a rock fragments mass with interstitial ice, wich confered a plastic behaviour to the assemblage. The age for these processes is estimate between 13.000 and 10.000 years B.P