Elements transposables, de l'excepció a la norma

Els elements transposables són seqüències amb la capacitat de canviar la seva posició en el genoma. Són uns components molt abundants, que en el cas del genoma humà representen fins al 50 % del genoma. Tot i la seva gran diversitat, es poden agrupar en dos grans tipus, segons el seu mecanisme de mobilització. Essencialment són considerats paràsits intracel·lulars, amb una gran habilitat per replicar-se i evitar ser eliminats per l'hoste. A més de mobilitzar-se dins del genoma i transmetre's verticalment a la descendència, molts elements transposables han estat capaços de saltar la barrera de les espècies i transferir-se horitzontalment entre els genomes. La genètica ha desenvolupat diferents mètodes per detectar els elements transposables dins de les seqüències genòmiques i estudiar-ne el comportament, tant dins com entre les espècies. En alguns casos el genoma ha domesticat un element transposable, que desenvolupa una funció cel·lular. Finalment, constitueixen una font de variabilitat, que és la matèria primera per a l'evolució de les espècies.Transposable elements are sequences with the ability to change their position in the genome. They are very abundant, representing up to 50% of the sequence in the case of the human genome. In spite of their high diversity they can be grouped into two big classes, according to their mechanism of mobilization. They are essentially considered to be intracellular parasites, with a great ability to replicate and to avoid elimination by the host. Besides mobilizing inside the genome and being vertically transmitted to descendants, several transposable elements have been able to cross the species borders, horizontally transmitting across genomes. Genetics has developed different methods to detect transposable elements in genome sequences, as well as to study their behavior within and between species. In some cases genomes have been able to domesticate some of them, those that are developing cellular functions. Finally, they are a source of variability, the raw material for the evolution of species

Theorical and descriptive analysis of the wave energy in the Barcelona World Race

The main objective of this paper is the presentation of a theoretical study of the wave energy in some zones of the Barcelona World Race (BWR) considering different theories, how much of this energy is transferred to the boat and if it is possible to use that energy, as propulsion energy. Nowadays, the absorption of wave energy (offshore, inshore or on board) is low utilized and has important costs. That makes this subject become more interesting. The first section of this paper is a study of the movement of the waves with different descriptions and of the energy potential depending on characteristic’s value. Secondly, a categorization of the wave’s characteristics is done of a part of BWR with the objective to be able to do an energy atlas of different areas. After that, a model of the vertical motion (simplified motion) is done in order to express the energy which is in the kinetic phase difference between the wave action and the boat reaction. Finally, all factors in the synchronism motion between wave and boat have been evaluated (in surf navigation) in order to analyze the results of equilibrium and the result force with different power propulsion.Postprint (published version

Theorical and descriptive analysis of the wave energy in the "Barcelona World Race"

The main objective of this paper is the presentation of a theoretical study of the wave energy in some zones of the Barcelona World Race (BWR) considering di erent theories, how much of this energy is transferred to the boat and if it is possible to use that energy, as propulsion energy. Nowadays, the absorption of wave energy (o shore, inshore or on board) is low utilized and has important costs. That makes this subject become more interesting. The first section of this paper is a study of the movement of the waves with di erent descriptions and of the power depending on characteristic’s value. Secondly, a categorization of the wave’s characteristics is done of a part of BWR with the objective to be able to do an energy atlas of di erent areas. After that, a model of the vertical motion (simplified motion) is done in order to express the energy which is in the kinetic phase di erence between the wave action and the boat reaction. Finally, all factors in the synchronism motion between wave and boat have been evaluated (in surf navigation) in order to analyze the results of equilibrium and the result force with di erent power propulsion.Postprint (published version

Multiple reflections and improvement of edge scattering in GRECO RCS prediction code

GRECO code for monostatic RCS prediction in real time has been extended by considering multiple reflections between surfaces and improving the edge diffraction coefficients. Multiple reflections are analysed through a very efficient ray-tracing algorithm based on the graphical processing technique. Method of equivalent currents for edge scattering has been improved by Mitzner's and Michaeli's incremental length diffraction coefficients (ILDC). This communication presents the general features of GRECO code, in particular the advantages of the new graphical processing technique. Emphasis will be placed in the new features of GRECO still unpublished: the ray-tracing algorithm and the implementation of incremental length diffraction coefficients. Multiple reflections and improvement of edge scattering in GRECO RCS prediction code. Available from: https://www.researchgate.net/publication/238507602_Multiple_reflections_and_improvement_of_edge_scattering_in_GRECO_RCS_prediction_code [accessed May 31, 2017].Peer ReviewedPostprint (published version

Testing dietary hypotheses of East African hominines using buccal dental microwear data

Abstract There is much debate on the dietary adaptations of the robust hominin lineages during the Pliocene-Pleistocene transition. It has been argued that the shift from C3 to C4 ecosystems in Africa was the main factor responsible for the robust dental and facial anatomical adaptations of Paranthropus taxa, which might be indicative of the consumption of fibrous, abrasive plant foods in open environments. However, occlusal dental microwear data fail to provide evidence of such dietary adaptations and are not consistent with isotopic evidence that supports greater C4 food intake for the robust clades than for the gracile australopithecines. We provide evidence from buccal dental microwear data that supports softer dietary habits than expected for P. aethiopicus and P. boisei based both on masticatory apomorphies and isotopic analyses. On one hand, striation densities on the buccal enamel surfaces of paranthropines teeth are low, resembling those of H. habilis and clearly differing from those observed on H. ergaster, which display higher scratch densities indicative of the consumption of a wide assortment of highly abrasive foodstuffs. Buccal dental microwear patterns are consistent with those previously described for occlusal enamel surfaces, suggesting that Paranthropus consumed much softer diets than previously presumed and thus calling into question a strict interpretation of isotopic evidence. On the other hand, the significantly high buccal scratch densities observed in the H. ergaster specimens are not consistent with a highly specialized, mostly carnivorous diet; instead, they support the consumption of a wide range of highly abrasive food items

Posibilidades del uso de tramas artificiales de imagen motora para un BCI basado en EEG

[Resumen] La utilización de una interfaz cerebro-computadora basada en el paradigma de la imagen motora requiere un entrenamiento para adaptar el sistema al cerebro del usuario. Este proceso de adecuación para crear un clasificador útil requiere un número muy elevado de tramas de señal EEG, y adquirir esas tramas requiere tiempo. Así, ahorrar tiempo de entrenamiento puede incrementar el tiempo dedicado al uso de la aplicación de la interfaz. Utilizando la descomposición EMD (Empirical Mode Decomposition) sobre las tramas EEG y mezclando sus IMFs (Intrinsic Mode Function), es posible crear nuevas tramas EEG artificiales e incrementar el número total de tramas para entrenar el clasificador. Los resultados preliminares del estudio muestran que las tasas de error de los clasificadores creados con tramas reales y artificiales mezcladas son similares a las tasas de error del clasificador creado solo con tramas reales. Estos resultados deberán ser confirmados con estudios futuros donde se pueda hacer una validación estadística de los mismo

Buccal dental microwear analyses support greater specialization in consumption of hard foodstuffs for Australopithecus anamensis

Molar occlusal microwear texture and anisotropy analyses of 3 Australopithecus anamensis fossil specimens have shown complexity values similar to those of Au. afarensis, indicating that neither of these hominin species had a diet dominated by hard food. However, many researchers have suggested that these were some of the earliest hominins to have such diets. Here we examine buccal microwear patterns of 5 Au. anamensis, 26 Au. afarensis, 48 Hominoidea and 80 Cercopithecoidea primate specimens for independent evidence of dietary adaptations of Au. anamensis. The buccal microwear results obtained suggest that the diet of Au. anamensis relied heavily on hard, brittle food, at least seasonally. This is similar to the diet of the extant Cercopithecoidea primates, including Papio anubis and Chlorocebus aethiops, both of which live in wooded, seasonal savannah environments and have diets that include fruit and grasses, but also underground storage organs (USOs), such as corms or blades, as well as leaves and seeds, and also Mandrillus and Cercocebus, from forested environments with frugivorous-granivorous diets. Furthermore, the buccal microwear patterns of Au. anamensis and Au. afarensis clearly differed -in clear contrast to occlusal enamel texture observations-, which support previous dietary interpretations based on both anatomical and palaeocological reconstructions

Nota metodológica: Alteración del patrón de microestriación dentaria por el efecto wrinkle.

Se describe el efecto wrinkle observado por primera vez sobre moldes dentarios realizados con resinas epoxy y metalizados en oro para su observación mediante microscopía electrónica de barrido (SEM). Con el fin de determinar en qué medida puede afectar al análisis del patrón de microestriación vestibular, se analizan dos muestras dentales de tres especies de Hominoideos, una de ellas incluyendo moldes con presencia de"aguas" relacionadas con el proceso de metalización. Se observa un descenso marcado de la variabilidad del patrón de microestriación dentaria anque las diferencias entre las dos muestras por especie no son estadísticamente significativas. El efecto wrinkle reduce significativamente el porcentaje de clasificación correcta de las especies analizadas a partir del patrón de microestriación y rugosidad dental utilizando un Análisis Discriminante. Se aconseja evitar la inclusión de las muestras afectadas por aguas en los estudios del patrón de microestriación dentaria

Fast algorithms for radar cross section computation of complex objects

Radar cross section (RCS) of complex targets can be obtained in real time using the hardware capabilities of a high performance graphic workstation. Target geometry is modelled by a computer-aided design package. First order contribution to RCS is computed under physical optics high-frequency approximation. Real time computation is achieved through graphical processing of an image obtained with local illumination modeling of the target. Multiple scattering contribution can be obtained using radiosity algorithm, a recently developed global illumination method.Peer ReviewedPostprint (published version

High-Frequency RCS of Perfectly Conducting or Coated Complex Objects in Real Time

This paper present a new and original approach to compute high-freqency radar cross section (RCS) of complex radar targets in real time using a 3-D graphic workstation. The aircraft is modelled with I-DEAS solid modeling software using a parametric surface approach. High-frequency RCS is obtained through Physical Optics (PO), Method of Equivalent Currents (MEC), Physical Theory of Diffraction (PTD) and Impedance Boundary Condition (IBC). Multiple scattering between target surfaces is also considered.Peer ReviewedPostprint (published version