Fernando Rico Delgado

Clostridium perfringens type E virulence traits involved in gut colonization.

Clostridium perfringens type E disease in ruminants has been characterized by hemorrhagic enteritis or sudden death. Although type E isolates are defined by the production of alpha and iota toxin, little is known about the pathogenesis of C. perfringens type E infections. Thus far, the role of iota toxin as a virulence factor is unknown. In this report, iota toxin showed positive effects on adherence and colonization of C. perfringens type E while having negative effect on the adherence of type A cells. In-vitro and in-vivo models suggest that toxinotype E would be particularly adapted to exploit the changes induced by iota toxin in the surface of epithelial cells. In addition, type E strains produce metabolites that affected the growth of potential intra-specific competitors. These results suggest that the alteration of the enterocyte morphology induced by iota toxin concomitantly with the specific increase of type E cell adhesion and the strong intra-specific growth inhibition of other strains could be competitive traits inherent to type E isolates that improve its fitness within the bovine gut environment.

Pre-Solutrean rock art in southernmost Europe: Evidence from Las Ventanas Cave (Andalusia, Spain)

The south of Iberia conserves an important group of Palaeolithic rock art sites. The graphisms have been mostly attributed to the Solutrean and Magdalenian periods, while the possibility that older remains exist has provoked extensive debate. This circumstance has been linked to both the cited periods, until recently, due to the transition from the Middle to Upper Palaeolithic in the extreme southwest of Europe as well as the non-existence of some of the early periods of Palaeolithic art documented in northern Iberia. This study presents the results of interdisciplinary research conducted in Las Ventanas Cave. These results enabled us to identify a new Palaeolithic rock art site. The technical, stylistic and temporal traits point to certain similarities with the range of exterior deep engravings in Cantabrian Palaeolithic rock art. Ventanas appears to corroborate the age attributed to those kinds of graphic expression and points to the early arrival of the Upper Palaeolithic in the south of Iberia. Importantly, the results provide information on the pre-Solutrean date attributed to trilinear hind figures. These findings challenge the supposed Neanderthal survival idea at one of the main late Middle Palaeolithic southern Iberian sites (Carigüela) and, due to the parallels between them and an engraving attributed to this period in Gibraltar, it raises the possibility of interaction between modern humans and Neanderthals in the extreme southwest of Europe.

Threshold Values for Energy Loss in Building Façades Using Infrared Thermography

The main factor in energy savings is the thermal envelope of buildings, where energy losses or gains with the exterior occur. This work proposes a new methodology to detect the most significant sectors in energy transmission through infrared thermography and the thermal intensity assessment of each opaque area, building element or thermal bridge, taking into account different values of wind speed. Thermal intensity values are then compared with the corresponding thermal transmittance threshold given in the regulations for each country, depending on the climate area. This method provides a specific view of the building elements and of the overall envelope in terms of energy loss using thermal intensity instead of the traditional heat transfer analysis. It thus results in quantitative energy loss through the shell. The main goal of this work is to select building elements or zones of a thermal envelope according to their energy losses in order to avoid an indiscriminate intervention on the opaque parts of envelopes. This research is significant as few studies have analysed global energy losses in buildings, quantitatively evaluating the thermal intensity of all the components of the opaque parts of facades. This study also advances in analysing the influence of different wind speeds in facades in order to assess the thermal behaviour of buildings when quasi-steady condition is lost.