Equine diet during protohistoric times in the Northeast of the Iberian Peninsula: Stable isotope data (C, N) from bone collagen

[Abstract] The analysis of stable isotopes in bone collagen allows us to infer the diet of the animals studied. This dataset consists of isotopic signatures (δ13C and δ15N) obtained by isotope ratio mass spectrometry from the skeletal remains of 42 equines (horse, ass and their hybrids) from the Can Roqueta site (Sabadell, Northeast Iberian Peninsula). Their chronology spans from Late Bronze Age to Late Roman Period, with particular emphasis on the Early Iron Age. These animals were found in storage silos and graves and were probably sacrificed as ritual offerings. The isotopic values are accompanied by data to assess the quality of the collagen analyzed. This fills a gap in equine isotopic values for this region and chronology, which may be of use to archaeologists interested in the study of livestock management or palaeodiet.Ministerio de Economía, Industria y Competitividad; HAR2017-87695-

Pastures and fodder for feeding equids 3000 years ago. The Can Roqueta site (Barcelona, Spain) as a model of equine herd management

Can Roqueta has provided a large number of equid and dog assemblages from the Late Bronze Age to the Early Iron Age. An analysis of the stable isotopes δ13C and δ15N in 42 bone samples has made it possible to reconstruct the diet of domestic equids. The results and carpological remains show that the territory was managed for agricultural and pasture use. They indicate the cultivation of two types of highly nutritious and digestible millet, used in combination with other cereals to prepare fodder, as well as the use of natural pastures

Equine diet during protohistoric times in the Northeast of the IberianPeninsula: stable isotope data (C, N) from bone collagen

The analysis of stable isotopes in bone collagen allows us to infer the diet of the animals studied. This dataset consists of isotopic signatures (δ13C and δ15N) obtained by isotope ratio mass spectrometry from the skeletal remains of 42 equines (horse, ass and their hybrids) from the Can Roqueta site (Sabadell, Northeast Iberian Peninsula). Their chronology spans from Late Bronze Age to Late Roman Period, with particular emphasis on the Early Iron Age. These animals were found in storage silos and graves and were probably sacrificed as ritual offerings. The isotopic values are accompanied by data to assess the quality of the collagen analysed. This fills a gap in equine isotopic values for this region and chronology, which may be of use to archaeologists interested in the study of livestock management or palaeodiet

Growth modes and chemical-phase separation in GaP1− x N x layers grown by chemical beam epitaxy on GaP/Si(001)

We investigated the chemical beam epitaxy of GaP 1 − x N x grown on nominally ( 001 ) -oriented Si substrates, as desired for the lattice-matched integration of optoelectronic devices with the standard Si technology. The growth mode and the chemical, morphological, and structural properties of samples prepared using different growth temperatures and N precursor fluxes were analyzed by several techniques. Our results show that, up to x ≈ 0.04 , it is possible to synthesize smooth and chemically homogeneous GaP 1 − x N x layers with a high structural quality. As the flux of the N precursor is increased at a given temperature to enhance N incorporation, the quality of the layers degrades upon exceeding a temperature-dependent threshold; above this threshold, the growing layer experiences a growth mode transition from 2D to 3D after reaching a critical thickness of a few nm. Following that transition, the morphology and the chemical composition become modulated along the [ 110 ] direction with a period of several tens of nm. The surface morphology is then characterized by the formation of { 113 } -faceted wires, while the N concentration is enhanced at the troughs formed in between adjacent ( 113 ) and ( 1 ¯ 1 ¯ 3 ) . On the basis of this study, we conclude on the feasibility of fabricating homogeneous thick GaP 1 − x N x layers lattice matched to Si ( x = 0.021 ) or even with N content up to x = 0.04 . The possibility of exceeding a N mole fraction of 0.04 without inducing coupled morphological-compositional modulations has also been demonstrated when the layer thickness is kept below the critical value for the 2D-3D growth mode transitionThis work was supported by the former Ministerio de Ciencia, Innovación y Universidades (Project No. TEC2016-78433-R), the current Ministerio de Ciencia e Innovación (Project Nos. PID2020-114280RB-I00 and PID2020-117024GB-C42), and the Ministry of Science and Higher Education of the Russian Federation (State assignment No. FSMR-2020-0018 and FSMR-2023-0003). Additionally, S. Fernández-Garrido acknowledges the financial support received through the program Ramón y Cajal (co-financed by the European Social Fund) under Grant No. RYC-2016-19509 from Ministerio de Ciencia, Innovación y Universidades. We also acknowledge the service from the MiNa Laboratory at IMN and funding from CM (project S2018/NMT-4291 TEC2SPACE), MINECO (project CSIC13-4E-1794), and EU (FEDER, FSE

Self-regulated radius of spontaneously formed GaN nanowires in molecular beam epitaxy

We investigate the axial and radial growth of GaN nanowires upon a variation of the Ga flux during molecular beam epitaxial growth. An increase in the Ga flux promotes radial growth without affecting the axial growth rate. In contrast, a decrease in the Ga flux reduces the axial growth rate without any change in the radius. These results are explained by a kinetic growth model that accounts for both the diffusion of Ga adatoms along the side facets towards the nanowire tip and the finite amount of active N available for the growth. The model explains the formation of a new equilibrium nanowire radius after increasing the Ga flux and provides an explanation for two well known but so far not understood experimental facts: the necessity of effectively N-rich conditions for the spontaneous growth of GaN nanowires and the increase in nanowire radius with increasing III/V flux ratios

Dogs that Ate Plants: Changes in the Canine Diet During the Late Bronze Age and the First Iron Age in the Northeast Iberian Peninsula

This is an Accepted Version of the article: this version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s10963-021-09153-9[Abstract] We studied 36 dogs (Canis familiaris) from the Can Roqueta site in the Catalan pre-littoral depression (Barcelona), dated between the Late Bronze Age and the First Iron Age (1300 and 550 cal BC). We used a sample of 27 specimens to analyse the evolution of the dogs’ diet based on the carbon δ13C and nitrogen δ15N isotope composition. The results show a marked human influence in that these natural carnivores display a highly plant-based diet. The offset between canids and herbivorous ungulates does not reach the minimum established for a trophic level, which implies an input of C3 and C4 (millet) cultivated plants. Moreover, the homogeneity in the values indicates that humans prepared their dogs’ food.This paper was written as part of the research undertaken by the consolidated research group SGR2017-00011 Seminari d’Estudis I Recerques Prehistòriques (SERP) and within the Projects HAR2013-48010-P and HAR2017-87695-P funded by the Spanish Ministry of Economy and Competitiveness. We want to thank the reviewers of this paper because their insights have helped improve the workCataluña. Generalitat; SGR2017-0001

Raman scattering by coupled plasmon-LO phonons in InN nanocolumns

Raman measurements on high quality, relaxed InN nanocolumns grown on Si(001) and Si(111) substrates by plasma-assisted molecular beam epitaxy are reported. A coupled LO phonon-plasmon mode around 430 cm-1, together with the uncoupled LO phonon appears in the nanocolumnar samples. The coupled mode is attributed to spontaneous accumulation of electrons at the lateral surfaces of the nanocolumns, while the uncoupled phonon originates from their inner part. Infrared reflectance measurements confirm the presence of electrons in the nanocolumns. The electron density in the accumulation layer depends on the growth temperature and is sensitive to exposure of HCl. Our results indicate that accumulation of intrinsic electrons occurs not only at the polar surfaces of InN layers, but also on non-polar lateral surfaces of InN nanocolumns. Its origin is attributed to an In-rich surface reconstruction of the nanocolumns sidewalls

Evidence of charge carrier number fluctuations in InN thin films?

Due to its small band-gap and its high mobility, InN is a promising material for a large number of key applications like band-gap engineering for high efficiency solar cells, light emitting diodes, and high speed devices. Unfortunately, it has been reported that this material exhibits strong surface charge accumulation which may depend on the type of surface. Current investigations are conducted in order to explain the mechanisms which govern such a behavior and to look for ways of avoiding it and/or finding applications that may use such an effect. In this framework, low frequency noise measurements have been performed at different temperatures on patterned MBE grown InN layers. The evolution of the 1/f noise level with temperature in the 77 K-300 K range is consistent with carrier number fluctuations thus indicating surface mechanisms: the surface charge accumulation is confirmed by the noise measurements

Band bending at In-rich InGaN surfaces

The band bending and carrier concentration profiles as a function of depth below the surface for oxidized InxGa1−xN alloys with a composition range of 0.39 ≤ x ≤ 1.00 are investigated using x-ray photoelectron, infrared reflection, and optical absorption spectroscopies, and solutions of Poisson’s equation within a modified Thomas–Fermi approximation. All of these InGaN samples exhibit downward band bending ranging from 0.19 to 0.66 eV and a high surface sheet charge density ranging from 5.0×1012 to 1.5×1013 cm−2. The downward band bending is more pronounced in the most In-rich InGaN samples, resulting in larger near-surface electron concentrations

Quasiparticle tunnel electroresistance in superconducting junctions

The term tunnel electroresistance (TER) denotes a fast, non-volatile, reversible resistance switching triggered by voltage pulses in ferroelectric tunnel junctions. It is explained by subtle mechanisms connected to the voltage-induced reversal of the ferroelectric polarization. Here we demonstrate that effects functionally indistinguishable from the TER can be produced in a simpler junction scheme-a direct contact between a metal and an oxide-through a different mechanism: a reversible redox reaction that modifies the oxide's ground-state. This is shown in junctions based on a cuprate superconductor, whose ground-state is sensitive to the oxygen stoichiometry and can be tracked in operando via changes in the conductance spectra. Furthermore, we find that electrochemistry is the governing mechanism even if a ferroelectric is placed between the metal and the oxide. Finally, we extend the concept of electroresistance to the tunnelling of superconducting quasiparticles, for which the switching effects are much stronger than for normal electrons. Besides providing crucial understanding, our results provide a basis for non-volatile Josephson memory devices. The non-volatile switching of tunnel electroresistance in ferroelectric junctions provides the basis for memory and neuromorphic computing devices. Rouco et al. show tunnel electroresistance in superconductor-based junctions that arises from a redox rather than ferroelectric mechanism and is enhanced by superconductivity