Indicios de pastoreo extensivo en el noroeste peninsular durante el dominio suevo

[Resumen:]Las condiciones edáficas de Galicia (NW de España), debido al sustrato ácido predominante, dificultan la conservación de los restos arqueozoológicos asociados a los asentamientos humanos. En estos casos, la búsqueda en zonas alternativas, como cuevas y trampas naturales en las zonas de pastoreo, puede aportar información sobre los recursos animales disponibles. Se presenta aquí un estudio de los restos de ganado vacuno doméstico encontrados en Cova da Tara o Tara da Triega (Serra do Courel, Lugo). Con una edad de alrededor de 1500 años, los huesos corresponderían a la época de la dominación sueva del Noroeste peninsular. Estos animales habrían llegado vivos a la cueva, de donde se deduce que deambulaban libremente en los alrededores, lo que señala un tipo de pastoreo extensivo. El desgaste dentario y el estudio de isótopos estables en el colágeno óseo reflejan una alimentación poco abrasiva, probablemente arbustiva, concordando con la de zonas de montaña. La talla media calculada para estos animales es pequeña, similar a la descrita para ganado vacuno prerromano.[Abstract:]The soil conditions in Galicia (NW of Spain), due to the predominant acid substrate, makes difficult the conservation of archaeozoological remains associated with human settlements. In these cases, the search for alternative areas, such as caves and natural traps in pasturelands, can provide information on the animal resources available.We present here a study about domestic cattle remains found in Cova da Tara or Tara da Triega (Serra do Courel, Lugo), with an age of about 1500 years BP. The bone remains were laid at the time of the Swabian domination of peninsular northwest. These animals would come alive to the cave, from which it follows that roamed freely around, indicating an extensive livestock management. The tooth wear and the study of stable isotopes in bone collagen reflect a little abrasive diet, probably shrub, matching the vegetation of mountain areas. The average height calculated for these animals is small, similar to that described for pre-Roman cattle

GaN and InN nanowires grown by MBE: a comparison

Morphological, optical and transport properties of GaN and InN nanowires grown by molecular beam epitaxy (MBE) have been studied. The differences between the two materials in respect to growth parameters and optimization procedure was stressed. The nanowires crystalline quality has been investigated by means of their optical properties. A comparison of the transport characteristics was given. For each material a band schema was shown, which takes into account transport and optical features and is based on Fermi level pinning at the surface.Comment: 5 pages, 5 figure

Paleogenomic Evidence for Multi-generational Mixing between Neolithic Farmers and Mesolithic Hunter-Gatherers in the Lower Danube Basin

The transition from hunting and gathering to farming involved profound cultural and technological changes. In Western and Central Europe, these changes occurred rapidly and synchronously after the arrival of early farmers of Anatolian origin [1-3], who largely replaced the local Mesolithic hunter-gatherers [1, 4-6]. Further east, in the Baltic region, the transition was gradual, with little or no genetic input from incoming farmers [7]. Here we use ancient DNA to investigate the relationship between hunter-gatherers and farmers in the Lower Danube basin, a geographically intermediate area that is characterized by a rapid Neolithic transition but also by the presence of archaeological evidence that points to cultural exchange, and thus possible admixture, between hunter-gatherers and farmers. We recovered four human paleogenomes (1.1× to 4.1× coverage) from Romania spanning a time transect between 8.8 thousand years ago (kya) and 5.4 kya and supplemented them with two Mesolithic genomes (1.7× and 5.3×) from Spain to provide further context on the genetic background of Mesolithic Europe. Our results show major Western hunter-gatherer (WHG) ancestry in a Romanian Eneolithic sample with a minor, but sizeable, contribution from Anatolian farmers, suggesting multiple admixture events between hunter-gatherers and farmers. Dietary stable-isotope analysis of this sample suggests a mixed terrestrial/aquatic diet. Our results provide support for complex interactions among hunter-gatherers and farmers in the Danube basin, demonstrating that in some regions, demic and cultural diffusion were not mutually exclusive, but merely the ends of a continuum for the process of Neolithization.This research was supported by a European Research Council (ERC) Starting Grant (ERC-2010-StG 263441) to R.P. G.G.-F. was also supported by MSC Individual Fellowship (NeoGenHeritage, grant no. 655478). E.R.J. was supported by a Herchel Smith Research Fellowship. M.H. and A.M. were supported by ERC consolidator grants 310763 GeneFlow and 647797 LocalAdaptation, respectively. V.S. was supported by the Gates Cambridge Trust. The work of C.L. was undertaken through the Partnerships in Priority Areas Program PN II, developed with the support of MEN-UEFISCDI (project no. PN-II-PTPCCA-2013-4-2302). A.G.-D. is supported by the research project BIOGEOS (CGL2014-57209-P) of the Spanish MINECO. The research of P.A., M.D.G., and L.D. on Los Canes is currently supported by the project CoChange (HAR2014-51830-P) of the Spanish State Plan for R+D+i (MINECO)

Effect of different buffer layers on the quality of InGaN layers grown on Si

This work studies the effect of four different types of buffer layers on the structural and optical properties of InGaN layers grown on Si(111) substrates and their correlation with electrical characteristics. The vertical electrical conduction of n-InGaN/buffer-layer/p-Si heterostructures, with In composition near 46%, which theoretically produces an alignment of the bands, is analyzed. Droplet elimination by radical-beam irradiation was successfully applied to grow high quality InGaN films on Si substrates for the first time. Among several buffer choices, an AlN buffer layer with a thickness above 24 nm improves the structural and optical quality of the InGaN epilayer while keeping a top to bottom ohmic behavior. These results will allow fabricating double-junction InGaN/Si solar cells without the need of tunnel junctions between the two sub-cells, therefore simplifying the device design

Insight into the introduction of domestic cattle and the process of Neolithization to the Spanish region Galicia by genetic evidence

Domestic cattle were brought to Spain by early settlers and agricultural societies. Due to missing Neolithic sites in the Spanish region of Galicia, very little is known about this process in this region. We sampled 18 cattle subfossils from different ages and different mountain caves in Galicia, of which 11 were subject to sequencing of the mitochondrial genome and phylogenetic analysis, to provide insight into the introduction of cattle to this region. We detected high similarity between samples from different time periods and were able to compare the time frame of the first domesticated cattle in Galicia to data from the connecting region of Cantabria to show a plausible connection between the Neolithization of these two regions. Our data shows a close relationship of the early domesticated cattle of Galicia and modern cow breeds and gives a general insight into cattle phylogeny. We conclude that settlers migrated to this region of Spain from Europe and introduced common European breeds to Galicia

Oxygen photo-adsorption related quenching of photoluminescence in group-III nitride nanocolumns

GaN and InGaN nanocolumns of various compositions are studied by room-temperature photoluminescence (PL) under different ambient conditions. GaN nanocolumns exhibit a reversible quenching upon exposure to air under constant UV excitation, following a t−1/2 time dependence and resulting in a total reduction of intensity by 85–90%, as compared to PL measured in vacuum, with no spectral change. This effect is not observed when exposing the samples to pure nitrogen. We attribute this effect to photoabsorption and photodesorption of oxygen that modifies the surface potential bending. InGaN nanocolumns, under the same experimental conditions do not show the same quenching features: The high-energy part of the broad PL line is not modified by exposure to air, whereas a lower-energy part, which does quench by 80–90%, can now be distinguished. We discuss the different behaviors in terms of carrier localization and possible composition or strain gradients in the InGaN nanocolumns

Apoyando la investigación: Nuevos roles en el servicio de bibliotecas de la Universidad de Navarra

La Biblioteca de la Universidad de Navarra ha ido asumiendo en los últimos años nuevos roles de apoyo a la investigación. Junto con tareas como formación a la carta o el fomento del acceso abierto a través del repositorio, se han iniciado asesoramientos a profesores en procesos de acreditación y solicitud de sexenios, así como colaboración con el sistema de gestión de datos de investigación en tareas de revisión y validación de la producción científica. Se detallan las nuevas funciones y tareas asumidas, su incidencia frente a las funciones tradicionales, las ventajas que han comportado y las líneas de futuro.In the last few years, the Library of the University of Navarra has taken on new librarian roles, mainly related to research support. Along with tasks such as on-demand training sessions and the promotion of open access to the Library’s repository, we have started several new lines of research support. These primarily focus on advising professors about accreditation processes and six-year research evaluations, and providing data review and item validation support for the institutional research management system. We analyze these new roles and tasks that have been undertaken, together with their impact on traditional tasks, their benefits, and new perspectives for the future

A western route of prehistoric human migration from Africa into the Iberian Peninsula

Being at the western fringe of Europe, Iberia had a peculiar prehistory and a complex pattern of Neolithization. A few studies, all based on modern populations, reported the presence of DNA of likely African origin in this region, generally concluding it was the result of recent gene flow, probably during the Islamic period. Here, we provide evidence of much older gene flow from Africa to Iberia by sequencing whole genomes from four human remains from northern Portugal and southern Spain dated around 4000 years BP (from the Middle Neolithic to the Bronze Age). We found one of them to carry an unequivocal sub-Saharan mitogenome of most probably West or West-Central African origin, to our knowledge never reported before in prehistoric remains outside Africa. Our analyses of ancient nuclear genomes show small but significant levels of sub-Saharan African affinity in several ancient Iberian samples, which indicates that what we detected was not an occasional individual phenomenon, but an admixture event recognizable at the population level. We interpret this result as evidence of an early migration process from Africa into the Iberian Peninsula through a western route, possibly across the Strait of Gibraltar