Biting is an integral feature of the feeding mechanism for aquatic and terrestrial salamanders to capture, fix or immobilize elusive or struggling prey. However, little information is available on how it works and the functional implications of this biting system in amphibians although such approaches might be essential to understand feeding systems performed by early tetrapods. Herein, the skull biomechanics of the Chinese giant salamander, Andrias davidianus is investigated using 3D finite element analysis. The results reveal that the prey contact position is crucial for the structural performance of the skull, which is probably related to the lack of a bony bridge between the posterior end of the maxilla and the anterior quadrato-squamosal region. Giant salamanders perform asymmetrical strikes. These strikes are unusual and specialized behavior but might indeed be beneficial in such sit-and-wait or ambush-predators to capture laterally approaching prey. However, once captured by an asymmetrical strike, large, elusive and struggling prey have to be brought to the anterior jaw region to be subdued by a strong bite. Given their basal position within extant salamanders and their “conservative” morphology, cryptobranchids may be useful models to reconstruct the feeding ecology and biomechanics of different members of early tetrapods and amphibians, with similar osteological and myological constraints.

For the first time in vertebrate palaeontology, the potential of joining Finite Element Analysis (FEA) and Parametrical Analysis (PA) is used to shed new light on two different cranial parameters from the orbits to evaluate their biomechanical role and evolutionary patterns. The early tetrapod group of Stereospondyls, one of the largest groups of Temnospondyls is used as a case study because its orbits position and size vary hugely within the members of this group. An adult skull of Edingerella madagascariensis was analysed using two different cases of boundary and loading conditions in order to quantify stress and deformation response under a bilateral bite and during skull raising. Firstly, the variation of the original geometry of its orbits was introduced in the models producing new FEA results, allowing the exploration of the ecomorphology, feeding strategy and evolutionary patterns of these top predators. Secondly, the quantitative results were analysed in order to check if the orbit size and position were correlated with different stress patterns. These results revealed that in most of the cases the stress distribution is not affected by changes in the size and position of the orbit. This finding supports the high mechanical plasticity of this group during the Triassic period. The absence of mechanical constraints regarding the orbit probably promoted the ecomorphological diversity acknowledged for this group, as well as its ecological niche differentiation in the terrestrial Triassic ecosystems in clades as lydekkerinids, trematosaurs, capitosaurs or metoposaurs.

The introduction of high-throughput techniques is increasingly providing abundant information on molecular alterations requiring validation at the posttranscriptional level. Protein expression is now efficiently evaluated in large series of tumors included in tissue microarrays. We propose, describe and validate a technique to elaborate paraffin-embedded cell line microarrays (PECLIMA) from fixed cell cultures, which can be processed like standard surgical pathology biopsies prior to immunophenotyping. Our results show a reliable protein immunoexpression profiling in six widely used cell lines under different fixation conditions. This technique permits the simultaneous analysis of multiple antigens in multiple cell lines under different experimental conditions. Additional features of these arrays are long-term storage, their suitability for a variety of techniques including immunocytochemistry and in situ hybridization and their low cost.

This paper presents the results of an extensive experimental campaign aimed to examine the effect upon the vibration response and on the residual load-bearing capacity caused by both: isolated artificially induced interlaminar damage and low-velocity impact induced damage in composite laminates. The experimental programme included modal testing, drop-weight impact testing, ultrasonic inspection, transverse quasi-static loading testing and compression testing conducted on a set of 72 carbon fibre-reinforced composite laminated coupons. Both types of damage caused measurable changes in laminate performance, however marked divergent trends were observed. The results allowed for conclusions to be drawn regarding the adequacy of the artificial damage approach and highlighted the importance and role of other forms of degradation upon damage tolerance of laminated composites containing damage.

No abstract

The main objective of this work is to generate a set of exercises to improve the autonomous learning in "Continuum Mechanics" through a virtual platform. Students will have to resolve four exercises autonomously related to the subject developed in class and they will post the solutions on the virtual platform within a deadline. Students will self-correct the exercises and assign a mark according to the rubric indicated by teachers. The work presented herein is based in applying the research done in autonomous learning by the Community of Practice GRAPAU of the RIMA Project (UPC-BarcelonaTech).

In palaeobiology it is common to consider bone like an isotropic material for simulations but often real data of bone materials is impossible to know. This work investigates the influence of choice of bone materials properties over the results of simulations, showing when and why the materials data are relevant and when the selection of these data becomes irrelevant. With a theoretical approach from continuum mechanics and with a practical example the relationship between material data and comparative metrics like stress, strains and displacements is discussed. When linear and elastic material properties are assumed in a comparative analysis, the effect of the elastic modulus of the material is irrelevant over stress patterns. This statement is true for homogeneous and inhomogeneous materials, in this last case the proportion between the different materials properties must kept constant. In the case of the strains and displacements, there is an inverse proportionality kept constant, between the values of the metrics and the changes in the elastic modulus. These properties allow comparative studies without considering the real elastic materials properties.

Fecha de recepción: marzo de 2015 Fecha de aceptación: junio de 2015de Biblid [(1130de -3743) 27, 2-2015 RESUMEN Este artículo trata de reflejar la dimensión educativa del trabajo que realizan las entidades sociales con mujeres en contextos de prostitución. Para ello, realizamos una investigación cualitativa basada en entrevistas, grupos de discusión, observación participante y relatos de vida, a tres tipos de informantes: especialistas en la materia, profesionales que trabajan sobre el terreno directamente con las mujeres y mujeres en contextos de prostitución. El análisis de la información nos permite visibilizar buena parte del contenido pedagógico que subyace en la intervención que se desarrolla en este ámbito. Desde esta perspectiva, los resultados que presentamos en