1,971 research outputs found

    Linking structural and compositional changes in archaeological human bone collagen: an FTIR-ATR approach

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    Collagen is the main structural and most abundant protein in the human body, and it is routinely extracted and analysed in scientific archaeology. Its degree of preservation is, therefore, crucial and several approaches are used to determine it. Spectroscopic techniques provide a cost-effective, non-destructive method to investigate the molecular structure, especially when combined with multivariate statistics (chemometric approach). In this study, we used FTIR-ATR spectroscopy to characterise collagen extracted from skeletons recovered from necropoleis in NW Spain spanning from the Bronze Age to eighteenth century AD. Principal components analysis was performed on a selection of bands and structural equation models (SEM) were developed to relate the collagen quality indicators to collagen structural change. Four principal components represented: (i) Cp1, transformations of the backbone protein with a residual increase in proteoglycans; (ii) Cp2, protein transformations not accompanied by changes in proteoglycans abundance; (iii) Cp3, variations in aliphatic side chains and (iv) Cp4, absorption of the OH of carbohydrates and amide. Highly explanatory SEM models were obtained for the traditional collagen quality indicators (collagen yield, C, N, C:N), but no relationship was found between quality and δ13C and δ15N ratios. The observed decrease in C and N content and increase in C:N ratios is controlled by the degradation of protein backbone components and the relative preservation of carbon-rich compounds, proteoglycans and, to a lesser extent, aliphatic moieties. Our results suggest that FTIR-ATR is an ideal technique for collagen characterization/pre-screening for palaeodiet, mobility and radiocarbon researchThis research was partially funded by the projects “Galician Paleodiet” (ED481D 2017/014), Consiliencia network (ED 431D2017/08), GPC (ED341B 2018/20) and “Antropoloxía dos restos óseos humanos de Galicia” (Dirección Xeral de Patrimonio Histórico), Xunta de Galicia. OLC is funded by Plan Galego I2C mod.B (ED481D 2017/014) and by Ministerio de Ciencia e Innovación (JIN project PID2019-111683RJ-100)S

    Recovery of an Abandoned Singular Infrastructure as a Key Factor for Regional Sustainable Development; A Study Case: “El Caminito del Rey” [“The King’s Little Path”]

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    Although the realm of sustainable development has been sharply associated with energy savings and a decrease in contamination, the concept deserves a much more comprehensive approach. Sustainable development, as the only respectful and safe way to progress, involves—besides the mentioned rational use of energy and resources—a broad variety of economic, technical, cultural, and behavioral issues. In this context, the total or partial recovery of abandoned singular infrastructure facilities for alternative uses (leisure time activities for human welfare) is to be considered an original, interesting, and efficient approach. In this research, the so-called “El Caminito del Rey” [The King’s Little Path] will be studied as a paradigmatic model of successful achievement. The path is located in Málaga, South of Spain, and was originally built to provide access to a hydroelectric power plant. Due to the construction of new routes, the track and walkways were progressively abandoned. The recovery enterprise was conceived in the framework of circular economy-based planning and with full respect to environmental requirements. The facts and figures that will be presented and analyzed will show that when the project is thoroughly designed and carefully implemented, the rehabilitation of obsolete infrastructure facilities located in natural spaces is suitable, feasible, and profitable. Prudent and rational use of these assets for alternative purposes (human welfare through rural tourism and open-air activities) may be fruitful not only in economic terms but also in environmental, cultural, and social ones. The main objective of the current work is to demonstrate that obsolete abandoned facilities can be rehabilitated into worthwhile amenities that may turn into key factors for the sustainable development of determined rural areas. Moreover, the “El Caminito del Rey” experience could represent a model for similar development projects

    Effect of pH and nanoclay content on the morphology and physicochemicalproperties of soy protein/montmorillonite nanocomposite obtained byextrusion

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    The present work attempts to clarify the influence of montmorillonite nanoclay content and pH on the me-chanical properties of extruded soy protein nanocomposites. The mechanical behaviour is dominated by theformation of positive synergies between protein and nanoclay above a nanoclay concentration threshold.Moreover, the presence of nanoclay can improve water uptake. The pH also exerts a strong influence on me-chanical and water absorption properties, although montmorillonite tend to reduce this effect.Eventually, this study put forward the feasibility of using a combination of soy protein and montmorillonite toobtain potentially attractive biodegradable nanocomposite materials, processed by means of a simple and easilyscalable twin-screw extruder.Junta de Andalucía (project TEP-6134)Ministerio de Economía y Competitividad (CTQ2015-71164-P

    Ecological Aspects and Conservation of Wild Grapevine Populations in the S.W. of the Iberian Peninsula

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    Populations of wild grapevine, Vitis vinifera L. subsp. sylvestris (Gmelin) Hegi, were discovered in S.W. of the Iberian Peninsula over the last years. Location, ecological aspects, sanitary characteristics, including the ELISA test to detect specific virus attack, are described. In vitro propagation and conservation are also considered. The paper also contains a global description of female and male individuals. This material could be used to start breeding programs of cultivated varieties and also to restore riverbank forests, which constitute one of the worst preserved ecosystems in the area

    Interaction Effects of Disruptive Behaviour and Motivation Profiles with Teacher Competence and School Satisfaction in Secondary School Physical Education

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    The objectives of this work were two-fold: Firstly, to identify the profiles of disruptive behaviours and motivation in secondary school physical education students using cluster analysis; and secondly, to analyse the interaction of the profiles with school satisfaction and perceived teaching competence. A group of 758 secondary school students (54.2% female) between the ages of 13 and 18 (M= 15.22, DT = 1.27) participated in the study by responding to the following scales: The Disruptive Behaviours in Physical Education Questionnaire, The School Satisfaction Scale, The Sport Motivation Scale adapted to Physical Education, and the Evaluation of Teaching Competencies Scale in Physical Education. The cluster analysis established two distinct profiles: High levels of disruptive behaviours and low levels of disruptive behaviours. The results showed that the students with the high disruptive behaviours profile were mostly boys, having low levels of intrinsic motivation and high levels of amotivation and misbehaviour in the classroom. In contrast, those students with the low disruptive behaviours profile were mostly girls, having the highest levels of intrinsic motivation and the lowest levels in all the disruptive behaviours. It was shown that students exhibiting the worse classroom behaviours were more bored in school, while those students with better behaviour perceived greater teaching competence

    Structural equation modelling of mercury intra-skeletal variability on archaeological human remains

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    Archaeological burial environments are useful archives to investigate the long-term trends and the behaviour of mercury. In order to understand the relationship between mercury, skeletons and soil, we applied Partial Least Squares - Structural Equation Modelling (PLS-SEM) to a detailed, multisampling (n = 73 bone samples +37 soil samples) design of two archaeological graves dating to the 6th to 7th centuries CE (A Lanzada site, NW Spain). Mercury content was assessed using a DMA-80, and data about bone structure and the grave soil/sediments were obtained using FTIR-ATR spectroscopy. The theoretical model is supported by proxies of bone structure, grave soil/sediments, and location of the bone within the skeleton. The general model explained 61 % of mercury variance. Additionally, Partial Least Square – Prediction Oriented Segmentation (PLS-POS) was also used to check for segmentation in the dataset. POS revealed two group of samples depending on the bone phase (hydroxyapatite or collagen) controlling the Hg content, and the corresponding models explained 86 % and 76 % of Hg variance, respectively. The results suggest that mercury behaviour in the graves is complex, and that mercury concentrations were influenced by i) the ante-mortem status of the bone matrix, related to the weight of each bone phase; ii) post-mortem evolution of bone crystallinity, where bone loses mercury with increasing alteration; and iii) the proximity of the skeletal pieces to mercury target organs, as decomposition and collapse of the thoracic and abdominal soft tissues causes a secondary mercury enrichment in bones from the body trunk during early post-mortem. Skeletons provide a source of mercury to the soil whereas soil/sediments contribute little to skeletal mercury contentPresent research was funded by Estudo de esqueletos humanos e de secuencias edafosedimentarias do xacemento de A Lanzada (2017-CP035) funded by Deputación Provincial de Pontevedra. The study was also supported by the projects “Pollutio” Plan Nacional (PID2019-111683RJ-I00) Spanish Ministerio de Ciencia e Innovacion, “Epidemias del hambre” Beca Leonardo a Investigadores y Creadores Culturales 2020 (2020-PO048) de la Fundación BBVA and “Grupos de Referencia Competitiva” (ED431C 2021/32) by Xunta de Galicia. NAF was funded by Convenio de Colaboración entre a Axencia Galega de Innovación, a Consellería de Cultura, Educación e Universidade, a USC e CSIC para fomentar a actividade Investigadora do persoal investigador finalista nas convocatorias de axudas do ERC no Marco do H2020. OLC is funded by a Ramón y Cajal senior fellowship (RYC2020-030531-I)S

    Desarrollo, calidad de educación y nuevas tecnologías

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    [Resumo] Hoxe por hoxe, xa ninguén dubida da existencia da violencia nos nosos centros educativos (cuns niveis preocupantes) e de que dalgún xeito, ternos que chegar a unha toma de decisións educativas, políticas, lexislativas,... En consonancia cá realidade que nos invade e considerando o ámbito educativo como un dos lugares más axeitado para o desenrolo de actividades dirixidas á erradicación desta violencia, presentamos aquí unha serie de "pautas" a ter en conta á partir dunha "actuación" transversal, comprometida e coherente do titor diante da organización escolar, os demais docentes, o propio alumnado, os pais, ... que nos leven a tal fin; pois o futuro dos/as nosos/as alumnos-las e da sociedade na que terán que vivir é o suficientemen-te fermoso e importante como para quedamos sen facer nada

    On the effect of random power availability in wireless power transfer systems with physical layer security

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    In this paper, we evaluate the performance of wireless powered communication systems from a physical layer security perspective. Our aim is to determine under which conditions the random power availability due to wireless power transmission using a dedicated power beacon impacts the maxi- mum secrecy rate, compared to its deterministic counterpart. We also investigate the effect of line-of-sight condition on the system performance. Analytical expressions are derived for some specific scenarios, which are combined with Monte Carlo simulations. We see that under a moderate line-of-sight condition in the wireless power transfer link, the secrecy performance is barely affected.Becas colaboración con departamentos Ministerio de Innovación (TEC-2017-87913R

    Mechanical design optimization for multi-finger haptic devices applied to virtual grasping manipulation

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    This paper describes the design of a modular multi-finger haptic device for virtual object manipulation. Mechanical structures are based on one module per finger and can be scaled up to three fingers. Mechanical configurations for two and three fingers are based on the use of one and two redundant axes, respectively. As demonstrated, redundant axes significantly increase workspace and prevent link collisions, which is their main asset with respect to other multi-finger haptic devices. The location of redundant axes and link dimensions have been optimized in order to guarantee a proper workspace, manipulability, force capability, and inertia for the device. The mechanical haptic device design and a thimble adaptable to different finger sizes have also been developed for virtual object manipulation
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