Computational modelling of cell migration in confined environments

Cell migration has gained attention over the last years due to its key role in different physiological and pathological process such as embryonic development and tumour growth [1]. Many researchers have developed studies about what stimulate the cells and the critical point in the cell mobility. In this work, we consider cell migration in microchannels, simulating the exact moment when the cell cross to the veins

Hábitos saludables: relación entre alimentación y actividad física en niños de 4º y 6º de educación primaria

Este trabajo de investigación está enfocado en los hábitos saludables en el alumnado de Educación Primaria, abordando más concretamente la actividad física y alimentación. Con este estudio se pretende examinar el grado de relación existente entre ambos aspectos y la importancia de su cumplimentación. La muestra total fue de 147 alumnos (60 chicas y 87 chicos) de 4º y 6º curso de Educación Primaria del Colegio Corazonistas La Mina de Zaragoza. Para la recogida de datos se utilizaron dos instrumentos de investigación cuantitativa, el cuestionario APALQ sobre actividad física y Krece Plus sobre hábitos alimentarios. El tratamiento de la información se ha abordado mediante el programa SSPS, que permite establecer un análisis estadístico. Los resultados exponen que tanto chicos como chicas de ambos cursos disponen de un nivel de actividad física moderadamente activo y un nivel nutricional medio. Los jóvenes que obtuvieron un mayor nivel nutricional resultaron obtener un mayor nivel de actividad física y viceversa, concluyendo con que ambos aspectos muestran una gran relación y por tanto son dependientes el uno del otro.<br /

Una propuesta didáctica para la enseñanza de la Combinatoria en 4º de E.S.O.

En el presente trabajo se analizan varios aspectos de la enseñanza de la Combinatoria en la Educación Secundaria Obligatoria, proponiendo una secuencia didáctica para impartir en la asignatura Matemáticas Orientadas a las Enseñanzas Académicas, en 4º de E.S.O.<br /

Gestión de la movilidad internacional de los Recursos Humanos

Mi trabajo versa sobre la Movilidad internacional de los Recursos Humanos, es decir, los aspectos relativos a los diferentes tipos de desplazamientos y como gestionarlos. En él se habla del concepto de expatriado, las cuestiones de Seguridad Social relativas a los desplazamientos, ventajas fiscales según la duración de los mismos, legislación aplicable en caso de contenciosos según la normativa interna española e internacional, y como se resuelven los casos de despidos tanto en caso de que el trabajador se encuentre en el país de destino, como si ha regresado a su país de origen. También se incluye un ejemplo de expatriación a Alemania para observar como se aplican las cuestiones anteriormente citadas

Effect of patch size on seed removal by harvester ants

The harvester ant Messor barbarus can be responsible for high weed seed losses in dry land cereals in Spain. Because weeds occur in patches, harvester ants have to be able to find and exploit patches. However, seed patches can differ in size and may, therefore, differ in the probability of being discovered and exploited. Here, 90 patches varying in size from 0.25 to 9 m2 were created in three 50 × 50 m subareas in a cereal field. Oat seeds were sown as weed seed surrogates in the patches at 2000 seeds m−2. After 24 h, those remaining were collected and the exploitation rate (the percentage of seeds removed per patch discovered by ants) was estimated. Harvester ant nests and the location of the seed patches were georeferenced and used to estimate distances between them. The patch encounter rate (the proportion of patches discovered by the ants) decreased slightly, but significantly, with decreasing patch size, though not the exploitation rate, which was lowest in the smallest patches (78-94%) and highest in the largest (99-100%). Seed patches that were not found or partially exploited were mostly located in subareas with a lower ant nest density or a longer distance away from the nearest nest than seed patches that were fully exploited. The results of this study indicate that the interaction between the spatial distribution of ant nests and the patchy distribution of seeds can create opportunities for seeds to be subjected to lower levels of predation

Simulación por elementos finitos de la deformación celular en ambientes confinados

Cell migration has gained attention over the last years due to its key role in different physiological and pathological process such as embryonic development and tumour growth. Many researchers have developed studies about what stimulate the cells and the critical point in the cell mobility. In this work, we consider cell migration in microchannels, simulating the moment when the cell cross extravase to the veins. Since the tool for elaborating that is the commercial software ABAQUS, a model with an axisymmetric Walker 256 carcinosarcoma cell with Neo-Hookean hyperelastic material and a rigid tube is described. In order to do that, two different parts are considered in the cell, membrane and nucleus, both clearly identify with different properties and features. As a result of the model presented, we found that not only the fluid drag and friction help to the cellular motion, but internal and biological aspects not developed before like the contraction of myosin and mainly, the protrusion of the actin affect strongly to the cell motility. A mathematical analysis, backed by the numerical simulations of cellular deformation, indicates that polymerization phenomenon and contractility play an important role in enabling cells to modify the external shape and let them moving towards for the migration direction

Comparative genomics of the Hedgehog loci in chordates and the origins of Shh regulatory novelties

The origin and evolution of the complex regulatory landscapes of some vertebrate developmental genes, often spanning hundreds of Kbp and including neighboring genes, remain poorly understood. The Sonic Hedgehog (Shh) genomic regulatory block (GRB) is one of the best functionally characterized examples, with several discrete enhancers reported within its introns, vast upstream gene-free region and neighboring genes (Lmbr1 and Rnf32). To investigate the origin and evolution of this GRB, we sequenced and characterized the Hedgehog (Hh) loci from three invertebrate chordate amphioxus species, which share several early expression domains with Shh. Using phylogenetic footprinting within and between chordate lineages, and reporter assays in zebrafish probing >30 Kbp of amphioxus Hh, we report large sequence and functional divergence between both groups. In addition, we show that the linkage of Shh to Lmbr1 and Rnf32, necessary for the unique gnatostomate-specific Shh limb expression, is a vertebrate novelty occurred between the two whole-genome duplications

Active yellow pages: a pipelined resource management architecture for wide-area network computing

This paper describes a novel, pipelined resource management architecture for computational grids. The design is based on two key realizations. One is that resource management involves a sequence of tasks that is best handled by a pipeline. As shown in the paper, this approach results, in a scalable architecture for decentralized scheduling. The other realization is that static aggregation of resources for improved scheduling is inadequate in wide-area computing environments because the needs of users and jobs change with both, location and time. The described architecture addresses this problem by dynamically aggregating resources in a manner that continuously optimizes system response. This is accomplished by way of an active yellow pages directory that allows aggregation constraints to be (re)defined on the fly. An initial prototype of the active yellow pages service has been deployed in the PUNCH network computing environment. Experiences with the production PUNCH system and preliminary results from controlled experiments indicate that the active yellow pages service performs well.Peer Reviewe