270 research outputs found
Evidence for weak electronic correlations in Fe-pnictides
Using x-ray absorption and resonant inelastic x-ray scattering, charge
dynamics at and near the Fe edges is investigated in Fe pnictide materials,
and contrasted to that measured in other Fe compounds. It is shown that the XAS
and RIXS spectra for 122 and 1111 Fe pnictides are each qualitatively similar
to Fe metal. Cluster diagonalization, multiplet, and density-functional
calculations show that Coulomb correlations are much smaller than in the
cuprates, highlighting the role of Fe metallicity and strong covalency in these
materials. Best agreement with experiment is obtained using Hubbard parameters
eV and eV.Comment: 11 pages, 12 figure
Full Multiple Scattering Analysis of XANES at the Cd L 3- and O K- Edges in CdO Films Combined with a Soft-X-Ray Emission Investigation
X-ray absorption near edge structure (XANES) at the cadmium L3 and oxygen K edges for CdO thin films grown by pulsed laser deposition method, is interpreted within the real-space multiple scattering formalism, FEFF code. The features in the experimental spectra are well reproduced by calculations for a cluster of about six and ten coordination shells around the absorber for L3 edge of Cd and K edge of O, respectively. The calculated projected electronic density of states is found to be in good agreement with unoccupied electronic states in experimental data and allows to conclude that the orbital character of the lowest energy of the conductive band is Cd 5s-O 2p[sigma]*. The charge transfer has been quantified and not purely ionic bonding has been found. Combined XANES and resonant inelastic x-ray scattering measurements allow us to determine the direct and indirect band gap of investigated CdO films to be ~2.4 eV and ~0.9 eV, respectively
Massive migration from the steppe is a source for Indo-European languages in Europe
We generated genome-wide data from 69 Europeans who lived between 8,000-3,000
years ago by enriching ancient DNA libraries for a target set of almost four
hundred thousand polymorphisms. Enrichment of these positions decreases the
sequencing required for genome-wide ancient DNA analysis by a median of around
250-fold, allowing us to study an order of magnitude more individuals than
previous studies and to obtain new insights about the past. We show that the
populations of western and far eastern Europe followed opposite trajectories
between 8,000-5,000 years ago. At the beginning of the Neolithic period in
Europe, ~8,000-7,000 years ago, closely related groups of early farmers
appeared in Germany, Hungary, and Spain, different from indigenous
hunter-gatherers, whereas Russia was inhabited by a distinctive population of
hunter-gatherers with high affinity to a ~24,000 year old Siberian6 . By
~6,000-5,000 years ago, a resurgence of hunter-gatherer ancestry had occurred
throughout much of Europe, but in Russia, the Yamnaya steppe herders of this
time were descended not only from the preceding eastern European
hunter-gatherers, but from a population of Near Eastern ancestry. Western and
Eastern Europe came into contact ~4,500 years ago, as the Late Neolithic Corded
Ware people from Germany traced ~3/4 of their ancestry to the Yamnaya,
documenting a massive migration into the heartland of Europe from its eastern
periphery. This steppe ancestry persisted in all sampled central Europeans
until at least ~3,000 years ago, and is ubiquitous in present-day Europeans.
These results provide support for the theory of a steppe origin of at least
some of the Indo-European languages of Europe
Accurate detection of identity-by-descent segments in human ancient DNA
Long DNA segments shared between two individuals, known as identity-by-descent (IBD), reveal recent genealogical connections. Here we introduce ancIBD, a method for identifying IBD segments in ancient human DNA (aDNA) using a hidden Markov model and imputed genotype probabilities. We demonstrate that ancIBD accurately identifies IBD segments >8 cM for aDNA data with an average depth of >0.25× for whole-genome sequencing or >1× for 1240k single nucleotide polymorphism capture data. Applying ancIBD to 4,248 ancient Eurasian individuals, we identify relatives up to the sixth degree and genealogical connections between archaeological groups. Notably, we reveal long IBD sharing between Corded Ware and Yamnaya groups, indicating that the Yamnaya herders of the Pontic-Caspian Steppe and the Steppe-related ancestry in various European Corded Ware groups share substantial co-ancestry within only a few hundred years. These results show that detecting IBD segments can generate powerful insights into the growing aDNA record, both on a small scale relevant to life stories and on a large scale relevant to major cultural-historical events
Educación cívica a través de la enseñanza de la Historia: una propuesta desde el Bachillerato Internacional y la LOMCE
La educación cívica, o educación para la ciudadanía, es fundamental para formar
ciudadanos capaces de interactuar de manera positiva en sociedad y de ejercer
conscientemente sus derechos y deberes. Es, por tanto, un elemento esencial si
entendemos la educación como un proceso de formación integral de la persona para que
ésta pueda desarrollar su propia identidad y evolucionar plenamente en su contexto social.
El respecto [a la diversidad] y el reconocimiento [a la aceptación de la variedad cultural]
dentro de una misma sociedad son dos valores universales que se constituyen en pilares
fundamentales para la construcción de ciudadanía y la coexistencia pacífica. La
legislación educativa vigente plantea de forma transversal la educación cívica en las
materias básicas. Este trabajo propone introducirla a través del estudio de la historia.Civic education, or education for citizenship, is cruc
ial to educate citizens capable of
interacting positively in society and of exercising their rights and duties in a conscious
manner. It is, therefore, an essential element if we understand education as an integral
process of the people so that they can de
velop their own identity and evolve fully in their
social context.
R
espect [for diversity] and recognition [for the acceptance of the cultural
variety] within the same society are two universal values
that constitute fundamental
pillars for the construct
ion of citizenship and peaceful coexistence. Given that current
legislation on education raises the mainstreaming of civic education in the core subjects
of the school curriculum, this work proposes introducing education for citizenship
through the study o
f history
Tracing the dynamic life story of a Bronze Age Female
YesAncient human mobility at the individual level is conventionally studied by the diverse application of suitable techniques (e.g. aDNA, radiogenic strontium isotopes, as well as oxygen and lead isotopes) to either hard and/or soft tissues. However, the limited preservation of coexisting hard and soft human tissues hampers the possibilities of investigating high-resolution diachronic mobility periods in the life of a single individual. Here, we present the results of a multidisciplinary study of an exceptionally well preserved circa 3.400-year old Danish Bronze Age female find, known as the Egtved Girl. We applied biomolecular, biochemical and geochemical analyses to reconstruct her mobility and diet. We demonstrate that she originated from a place outside present day Denmark (the island of Bornholm excluded), and that she travelled back and forth over large distances during the final months of her life, while consuming a terrestrial diet with intervals of reduced protein intake. We also provide evidence that all her garments were made of non-locally produced wool. Our study advocates the huge potential of combining biomolecular and biogeochemical provenance tracer analyses to hard and soft tissues of a single ancient individual for the reconstruction of high-resolution human mobility.The Danish National Research Foundation; The Carlsberg Foundation, L'Oreal Denmark-UNESCO; The ERC agreement no. 26944
Geographic genetic structure of Iberian columbines (gen. Aquilegia)
Southern European columbines (genus Aquilegia)are involved in active processes of diversification, and the Iberian Peninsula offers a privileged observatory to witness the process. Studies on Iberian columbines have provided significant advances on species diversification,but we still lack a complete perspective of the genetic diversification in the Iberian scenario. This work explores how genetic diversity of the genus Aquilegia is geographically structured across the Iberian Peninsula. We used Bayesian clustering methods, principal coordinates analyses, and NJ phenograms to assess the genetic relationships among 285 individuals from 62 locations and detect the main lineages. Genetic diversity of Iberian columbines consists of five geographically structured lineages, corresponding to different Iberian taxa. Differentiation among lineages shows particularly complex admixture patterns at Northeast and highly homogeneous toward Northwest and Southeast. This geographic genetic structure suggests the existence of incomplete lineage sorting and interspecific hybridization as could be expected in recent processes of diversification under the influence of quaternary postglacial migrations. This scenario is consistent with what is proposed by the most recent studies on European and Iberian columbines, which point to geographic isolation and divergent selection by habitat specialization as the main diversification drivers of the Iberian Aquilegia complex
Osteogenic differentiation of human dental pulp stem cells in decellularised adipose tissue solid foams
3D cell culture systems based on biological scaffold materials obtainable from both animal and human tissues constitute very interesting tools for cell therapy and personalised medicine applications. The white adipose tissue (AT) extracellular matrix (ECM) is a very promising biomaterial for tissue engineering due to its easy accessibility, malleability and proven biological activity. In the present study, human dental pulp stem cells (hDPSCs) were combined in vitro with ECM scaffolds from porcine and human decellularised adipose tissues (pDAT, hDAT) processed as 3D solid foams, to investigate their effects on the osteogenic differentiation capacity and bone matrix production of hDPSCs, compared to single-protein-based 3D solid foams of collagen type I and conventional 2D tissue-culture-treated polystyrene plates. pDAT solid foams supported the osteogenic differentiation of hDPSCs to similar levels to collagen type I, as assessed by alkaline phosphatase and alizarin red stainings, reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and osteocalcin/bone gamma-carboxyglutamate protein (BGLAP) immunostaining. Interestingly, hDAT solid foams showed a markedly lower capacity to sustain hDPSC osteogenic differentiation and matrix calcification and a higher capacity to support adipogenesis, as assessed by RT-qPCR and oil red O staining. White ATs from both human and porcine origins are relatively abundant and available sources of raw material to obtain high quality ECM-derived biomedical products. These biomaterials could have promising applications in tissue engineering and personalised clinical therapy for the healing and regeneration of lesions involving not only a loss of calcified bone but also its associated soft non-calcified tissues.This research was supported by the Basque Government (ELKARTEK program PLAKA KK2019-00093; to NB), MICINN retos I+D+i (PID2019- 104766RB-C21, to JRP) and UPV/EHU (PPGA20/22; to FU, GI). The authors would like to thank the staff members of the SGIKER services of the UPV/EHU: Lipidomic service (Beatriz Abad) and Analytical Microscopy (Ricardo Andrade, Alejandro Díez-Torre and Irene Fernández) for their technical assistance
New insights into the neolithisation process in southwest Europe according to spatial density analysis from calibrated radiocarbon dates
The agricultural way of life spreads throughout Europe via two main routes: the Danube corridor and the Mediterranean basin. Current archaeological literature describes the arrival to the Western Mediterranean as a rapid process which involves both demic and cultural models, and in this regard, the dispersal movement has been investigated using mathematical models, where the key factors are time and space. In this work, we have created a compilation of all available radiocarbon dates for the whole of Iberia, in order to draw a chronological series of maps to illustrate temporal and spatial patterns in the neolithisation process. The maps were prepared by calculating the calibrated 14C date probability density curves, as a proxy to show the spatial dynamics of the last hunter-gatherers and first farmers. Several scholars have pointed out problems linked with the variability of samples, such as the overrepresentation of some sites, the degree of regional research, the nature of the dated samples and above all the archaeological context, but we are confident that the selected dates, after applying some filters and statistical protocols, constitute a good way to approach settlement spatial patterns in Iberia at the time of the neolithisation process
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