A 3-D boundary element model for the dynamic analysis of arch dams with porous sediments

A three-dimensional boundary element technique for dynamic analysis of arch dams including dynamic interaction and sediments on the bottom of the reservoir is presented. The dam and the foundation rock are assumed to be viscoelastic domains with linear behaviour. The water is assumed to be compressible and the sediment is considered as a two-phase poroelastic material according to Biot's theory. The four domains (dam, foundation rock, water and bottom sediments) are discretized and the interaction between them is rigorously represented. The effects of sediments on the dynamic response of arch dams are evaluated for rigid and compliant foundation. Upstream, vertical and cross-stream excitation are considered. The influence of the degree of saturation of the sediment is analysed. Other modelling of the sediment as a single-phase scalar medium are considered in order to reduce the degrees of freedom of the system.Ministerio de Ciencia y Tecnología PB96-1322-C03-0

Be analysis of bottom sediments in dynamic fluid-structure interaction problems

Sediment materials play an important role on the dynamic response of large structures where fluid-soil-structure interaction is relevant and materials of that kind are present. Dam-reservoir systems and harbor structures are examples of civil engineering constructions where those effects are significant. In those cases the dynamic response is determined by hydrodynamic water pressure, which depends on the absorption effects of bottom sediments. Sediments of very different mechanical properties may exist on the bottom. A three-dimensional BE model for the analysis of sediment effects on dynamic response of those structures is presented in this paper. One of the most extended models for sediment materials corresponds to Biot’s fluid-filled poroelastic solid. The BE formulation for dynamics of poroelastic solids is reviewed including a weighted residual formulation more general and concise than those previously existing in literature. Systems consisting of water, other pressure wave propagating materials, viscoelastic solids and fluid-filled poroelastic zones, are studied. Coupling conditions at interfaces are taken into account in a rigorous way. A simple geometry coupled problem is first studied to asses the effects of sediments on its dynamic response and to determine the influence of parameters such as sediment depth, consolidation, compressibility and permeability. A fully 3-D arch dam-reservoir-foundation system where sediments and radiation damping play an important role is also studied in this paper. Obtained results show the importance of a realistic representation of sediments and the influence of their consolidation degree, compressibility and permeability on the system dynamic response.Ministerio de Ciencia y Tecnología BIA2004-03955-C02-01/0

Extraction and spectrophotometric and fluorimetric determination of micrograms of zinc in plants

9 pág.[ES] Se han aplicado dos nuevos métodos originales, espectrofotométrico y fluorimétrico, a la determinación de microgramos de cinc en material vegetal. Después de la disolución de la muestra, el cinc se extrae en solución 0,05 M de trioctilamina en tolueno, desde soluciones 1-3 M HCl en fase acuosa. El desarrollo del color o de la fluorescencia se efectua en la misma fase orgánica de la extracción sin efectuar re-extracción a fase acuosa, mediante adición de solución de oxina en N,N-dimetilformamida (DMF) y de solución de t-butil-amina en DMF. La absorbancia se mide a 403 nm. La ley de Beer se cumple en el intervalo de 1 a 10 mg. ml-1 de cinc en la fase orgánica final. La desviación estandar relativa para diez determinaciones de 50 mg. de cinc fue de 0,8%. En el método fluorimétrico, se ha empleado una radiación de excitación de 403 nm de longitud de onda y una emisión de fluorescencia de 450 nm. La intensidad relativa de fluorescencia de 450 nm. La intensidad relativa de fluorescencia era lineal con la concentración de cinc en el intervalo de 0,01 a 1 mg. ml-1) en la fase orgánica final. La desviación estandar relativa en la determinación fluorimétrica para diez determinaciones de 0,5 mg. de cinc fué de 2,2%. El valor medio de la recuperación de 0,5 mg de cinc añadidos a las soluciones de las muestras fué del 98,5%. Los resultados obtenidos en la determinación de cinc por ambos métodos propuestos en muestras de material vegetal suministradas amablemente por M. PINTA del Comité Inter-Institutos de Análisis Foliar, muestran buena precisión y exactitud.[EN] Two new spectrophotometric and fluorimetric methods for micrograms determination of zinc have been applied to plants analysis. After dissolution of the sample, zinc was extracted into 0.05 M trioctylamine in toluene solution from 1-3 M HCl aqueous solution. The development of the colour or the fluorescence was carried out in the same organic phase of the extraction, without back-extraction into aqueous phase, by addition of oxine solution in N, N-dimenthylformamide and t-butylamine in DMF solution. In the spectrophotometric method the absorbance was measured at 403 nm. Beer's law was obeyed in the range from 1 up to 10µg. ml-1 of zinc in the organic phase. The relative standard deviation for ten determinations of 50 µg. of zinc was 0,8%. In the f1uorimetric method a wavelength excitation radiation of 403 nm and a wavelength fluorescence emission of 450 nm were used. The relative intensity of f1uorescence was linear with the concentration of zinc in the range from 0.01 up to 1 µg. ml-1 of zinc in the organic phase. The standard relative deviation in the f1uorimetric determination for ten determinations of 0.5 µg of zinc was 2.2%. The mean recovery of 0.5 µg of zinc in spiked solutions was 98.5%. The results obtained for the determinations of zinc by both proposed methods in plants supplied by M. PINTA (Comité Inter-Instituts pour l'Analyse Foliaire) show good accuracy and precision.Peer reviewe

A proposal for normalized impedance functions of inclined piles in non-homogeneous media

10th International Conference on Structural Dynamics (EURODYN). Sapienza University Rome, September, 10-13, 2017.This work presents impedance functions for inclined pile groups embedded in different half spaces whose stiffness continuously increases with depth. The results are obtained through a three-dimensional harmonic model where the soil response is modelled through the reciprocity theorem in elastodynamics and the use of Green’s functions for the layered half space, while the piles are represented by finite elements as Timoshenko’s beams. Linear behaviour of soil and piles is assumed. The use of several normalization schemes for the representation of the impedance functions is discussed, highlighting the benefits and drawbacks of each choice and their effects on the interpretation of the obtained results. As a result, expressions for the dimensionless impedance functions and frequency are proposed in order to synthesize the results of the different soil profiles into the same curves. The final objective of the proposed normalization is to transform the well-known impedance functions for the homogeneous halfspace into the corresponding curves for a specific non-homogeneous profile that can be used, e.g., in a substructuring methodology. Despite the fact that the presence of soil non-homogeneity increases the dependence of the impedance functions on the frequency, good agreements between the homogeneous and non-homogeneous profiles can be achieved for a range of frequency of interest.This work was supported by Subdirección General de Proyectos de Investigación of the Ministerio de Economía y Competitividad (MINECO) of Spain and FEDER through research project BIA2014-57640-R. G.M. Álamo is a recipient of FPU research fellowship FPU14/06115 from the Ministerio de Educación, Cultura y Deporte of Spain

On soil-structure interaction in large non-slender partially buried structures

This paper addresses the seismic analysis of a deeply embedded non-slender structure hosting the pumping unit of a reservoir. The dynamic response in this type of problems is usually studied under the assumption of a perfectly rigid structure using a sub-structuring procedure (three-step solution) proposed specifically for this hypothesis. Such an approach enables a relatively simple assessment of the importance of some key factors influencing the structural response. In this work, the problem is also solved in a single step using a direct approach in which the structure and surrounding soil are modelled as a coupled system with its actual geometry and flexibility. Results indicate that, quite surprisingly, there are significant differences among prediction using both methods. Furthermore, neglecting the flexibility of the structure leads to a significant underestimation of the spectral accelerations at certain points of the structure

Robust estimation of fractal measures for characterizing the structural complexity of the human brain: optimization and reproducibility

High-resolution isotropic three-dimensional reconstructions of human brain gray and white matter structures can be characterized to quantify aspects of their shape, volume and topological complexity. In particular, methods based on fractal analysis have been applied in neuroimaging studies to quantify the structural complexity of the brain in both healthy and impaired conditions. The usefulness of such measures for characterizing individual differences in brain structure critically depends on their within-subject reproducibility in order to allow the robust detection of between-subject differences. This study analyzes key analytic parameters of three fractal-based methods that rely on the box-counting algorithm with the aim to maximize within-subject reproducibility of the fractal characterizations of different brain objects, including the pial surface, the cortical ribbon volume, the white matter volume and the grey matter/white matter boundary. Two separate datasets originating from different imaging centers were analyzed, comprising, 50 subjects with three and 24 subjects with four successive scanning sessions per subject, respectively. The reproducibility of fractal measures was statistically assessed by computing their intra-class correlations. Results reveal differences between different fractal estimators and allow the identification of several parameters that are critical for high reproducibility. Highest reproducibility with intra-class correlations in the range of 0.9–0.95 is achieved with the correlation dimension. Further analyses of the fractal dimensions of parcellated cortical and subcortical gray matter regions suggest robustly estimated and region-specific patterns of individual variability. These results are valuable for defining appropriate parameter configurations when studying changes in fractal descriptors of human brain structure, for instance in studies of neurological diseases that do not allow repeated measurements or for disease-course longitudinal studies

The neural substrate and functional integration of uncertainty in decision making: an information theory approach

Decision making can be regarded as the outcome of cognitive processes leading to the selection of a course of action among several alternatives. Borrowing a central measurement from information theory, Shannon entropy, we quantified the uncertainties produced by decisions of participants within an economic decision task under different configurations of reward probability and time. These descriptors were used to obtain blood oxygen level-dependent (BOLD) signal correlates of uncertainty and two clusters codifying the Shannon entropy of task configurations were identified: a large cluster including parts of the right middle cingulate cortex (MCC) and left and right pre-supplementary motor areas (pre-SMA) and a small cluster at the left anterior thalamus. Subsequent functional connectivity analyses using the psycho-physiological interactions model identified areas involved in the functional integration of uncertainty. Results indicate that clusters mostly located at frontal and temporal cortices experienced an increased connectivity with the right MCC and left and right pre-SMA as the uncertainty was higher. Furthermore, pre-SMA was also functionally connected to a rich set of areas, most of them associative areas located at occipital and parietal lobes. This study provides a map of the human brain segregation and integration (i.e., neural substrate and functional connectivity respectively) of the uncertainty associated to an economic decision making paradigm

Deep Sequencing of Target Linkage Assay-Identified Regions in Familial Breast Cancer: Methods, Analysis Pipeline and Troubleshooting

Background: The classical candidate-gene approach has failed to identify novel breast cancer susceptibility genes. Nowadays, massive parallel sequencing technology allows the development of studies unaffordable a few years ago. However, analysis protocols are not yet sufficiently developed to extract all information from the huge amount of data obtained. Methodology/Principal Findings: In this study, we performed high throughput sequencing in two regions located on chromosomes 3 and 6, recently identified by linkage studies by our group as candidate regions for harbouring breast cancer susceptibility genes. In order to enrich for the coding regions of all described genes located in both candidate regions, a hybrid-selection method on tiling microarrays was performed. Conclusions/Significance: We developed an analysis pipeline based on SOAP aligner to identify candidate variants with a high real positive confirmation rate (0.89), with which we identified eight variants considered candidates for functiona

Implications of Unconnected Micro, Molecular, and Molar Level Research in Psychology: The Case of Executive Functions, Self-Regulation, and External Regulation

The proliferation of research production in Psychology as a science has been increasing exponentially. This situation leads to the necessity of organizing the research production into different levels of analysis that make it possible to delimit each research domain. The objective of this analysis is to clearly distinguish the different levels of research: micro-analysis, molecular, and molar. Each level is presented, along with an analysis of its benefits and limitations. Next, this analysis is applied to the topics of Executive Functions, Self-Regulation, and External Regulation. Conclusions, limitations, and implications for future research are offered, with a view toward a better connection of research production across the different levels, and an allusion to ethical considerations

Duodenal Adenomas and Cancer in MUTYH-associated Polyposis: An International Cohort Study

Although duodenal adenomas and cancer appear to occur significantly less frequently in autosomal recessive MUTYH-associated polyposis (MAP) than in autosomal dominant familial adenomatous polyposis (FAP),1 current guidelines recommend similar endoscopic surveillance for both disorders.2-4 This involves gastro-duodenoscopy starting at 25 to 35 years of age and repeated at intervals determined by Spigelman staging based on the number, size, histological type and degree of dysplasia of adenomas, and by ampullary staging. Case reports of duodenal cancers in MAP suggest that they may develop in the absence of advanced Spigelman stage benign disease and even without coexisting adenomas.1 Recent molecular analyses suggest thatMAPduodenal adenomashave a higher mutational burden than FAP adenomas and are more likely to harbor oncogenic drivermutations, such as those in KRAS.5 These apparent differences in the biology and natural history of duodenal polyposis in FAP and MAP challenge the assumption that the same surveillance should be applied in both conditions