2,836 research outputs found

    Ensamblando datos. SIG y la historia humana del Valle de Oukaïmeden

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    Geographic Information Systems have become recently a methodological device to analyze the social configuration of historical landscapes. This paper deals with mobility and visibility as basic agents of the landscape organization, which is in turn, one of the theoretical bases of ARPA’s project. Hence, the need of applying these methodological tools to achieve a deeper knowledge of that process. GIS techniques show a direct connection between rock art or tumuli and the most efficient lines of movement, the best visibility orientations or the wet areas. Following Annales’ idea of Longue Durée, this paper traces the human process of modelling the Oukaïmeden landscape, from prehistoric times to more recent, historical ones, in which the control of critical resources and of mobility played a key role.Los sistemas de información geográfica han sido utilizados en los últimos años como herramienta metodológica a la hora de analizar la configuración social de los paisajes prehistóricos. En nuestro trabajo, y como una de las líneas teóricas de nuestro proyecto, entendemos la importancia de factores como la movilidad o la visibilidad dentro de esta configuración del paisaje. De ahí, la necesidad del uso de este tipo de herramientas metodológicas para comprender de una manera más profunda dicho proceso. La aplicación de los sistemas de información geográfica a la hora de analizar el arte rupestre y otra serie de elementos materiales prehistóricos, como los túmulos, parecen mostrarnos una relación directa entre dichas evidencias y factores tales como las líneas de movimiento, los condicionantes de visibilidad o las zonas de acumulación de pastos. De esta manera, y siguiendo la idea de la Longue Durée, hemos analizado la configuración del paisaje del valle de Oukaïmeden desde épocas prehistóricas hasta momentos más recientes, pudiendo entender como el control de los recursos y la movilidad, han sido factores determinantes en dicho proceso

    Preparation of Pt/CNT Thin-Film Electrodes by Electrochemical Potential Pulse Deposition for Methanol Oxidation

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    High-quality performance of catalysts is increasingly required to meet industry exigencies. However, chemical synthesis is often insufficient to maximize the potential properties of the catalysts. On the other hand, electrochemical synthesis has arisen as a promising alternative to overcome these limitations and provide precise control in the preparation of catalysts. In this sense, this work involved the well-controlled electrochemical synthesis of a catalyst based on platinum nanoparticle deposition on carbon nanotubes using only electrochemical treatments. Thin films of functionalized carbon nanotubes were cast onto the surface of a glassy carbon electrode using potential pulsed electrodeposition, resulting in a better distribution of the carbon nanotubes on the electrode when comparing with traditional methods. Then, platinum nanoparticles were electrodeposited on the carbon nanotube-modified electrode. To check the performance of the catalyst and the relevance of the electrochemical synthesis treatments, the samples were analyzed as electrocatalysts towards methanol electrooxidation, showing an important improvement in the catalytic activity in comparison with electrodes that were prepared by traditional methodologies.This research was funded by MICINN and FEDER (RTI2018-095291-B-I00 and PID2019-105923RB-I00), “Juan de la Cierva” contract (IJCI-2016-27636), and the Vicerrectorado de Investigación y Transferencia de Conocimiento de la Universidad de Alicante (GRE19-16)

    A Novel Displacement-amplifying Compliant Mechanism Implemented on a Modified Capacitive Accelerometer

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    The micro-accelerometers are devices used to measure acceleration. They are implemented in applications such as tilt-control in spacecraft, inertial navigation, oil exploration, etc. These applications require high operating frequency and displacement sensitivity. But getting both high parameter values at the same time is difficult, because there are physical relationships, for each one, where the mass is involved. When the mass is reduced, the operating frequency is high, but the displacement sensitivity decreases and vice versa. The implementation of Displacement-amplifying Compliant Mechanism (DaCM) supports to this dependence decreases. In this paper the displacement sensitivity and operation frequency of a Conventional Capacitive Accelerometer are shown (CCA). A Capacitive Accelerometer with Extended Beams (CAEB) is also presented, which improves displacement sensitivity compared with CCA, and finally the implementation of DACM´s in the aforementioned devices was also carried out. All analyzed cases were developed considering the in-plane mode. The Matlab code used to calculate displacement sensitivity and operating frequency relationship is given in Appendix A

    Conclusiones y nuevas vías de análisis

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    Main conclusions achieved by the ARPA project are discussed in the present paper. Although we do not discard previous sporadic visits, up to now, the oldest evidences of human regular use of the Oukaïmeden valley date back to the Late Neolithic, coinciding with changes in the African Monsoon. Combining archaeology, paleoecological information, 14C, art, and statistics and using GIS tools, we offer an interpretation of the human use of the valley in Prehistory.El artículo discute las principales conclusiones del proyecto ARPA. Sin negar la posibilidad de visitas esporádicas previas, la evidencia más antigua del uso humano regular del valle de Oukaïmeden se remonta al Neolítico reciente, coincidiendo con cambios en el Monzón africano. Combinando arqueología, información paleoecológica, C-14, arte y estadística y mediante herramientas SIG, ofrecemos una interpretación del uso humano del valle en la Prehistoria

    A considerable improvement of the traditional FPGA-based digital design methodology by using an Arduino sensor board

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    [EN] The traditional way to learn and teach Digital Systems has been changing over the last decades by the use of Hardware Description Languages (HDL) and Field Programmable Gate Array (FPGA) evaluation boards. The use of an Arduino development kit with different sensors connected to the FPGA upsizes the students experience in the area of Digital Systems. A temperature and humidity ambience sensor combined with an ultrasound sensor to measure distance can effectively be used by students to implement its first serial data converter that takes the sensor data and shows the obtained values from the Arduino in the seven segment display of the FPGA kit. After three years of experience in the new grade courses at the UPV Telecommunication School the number of students enjoying this new way to learn the subject Fundamentals of Digital Electronics (FSD) has dramatically risen up with an increase of a 20% in the number of students that pass the subject and that select the electronic branch of telecommunication studies in the future semesters.Martínez Peiró, MA.; Larrea Torres, MÁ.; Lidon Roger, J.; Jiménez Jiménez, Y.; Torres Curado, R.; Tébar Ruiz, Á. (2020). A considerable improvement of the traditional FPGA-based digital design methodology by using an Arduino sensor board. Editorial Universitat Politècnica de València. 81-89. https://doi.org/10.4995/INN2019.2019.10091OCS818

    Hypoxia signaling and cholesterol/steroidogenic acute regulatory protein 1 axis: interplay and role in alcohol and non-alcohol-related liver diseases

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    Metabolic zonation in the liver carries out the maintenance of organ and body homeostasis. Hypoxia is an inherent physiological feature of the liver and contributes to the zonal properties of the hepatic parenchyma. As a master regulator of hypoxia, the transcription factor hypoxia-inducing factor (HIF) is stabilized primarily by oxygen availability, and it is thought to contribute to steatohepatitis due to alcohol-related (ASH) and non-alcohol-related liver disease (NASH). Cholesterol has emerged as an important player in both diseases, and hypoxia increases hepatic cholesterol levels. Steroidogenic acute regulatory protein 1 (STARD1) is a mitochondrial outer membrane protein that transfers cholesterol to mitochondrial inner membrane for metabolic processing and acts as the rate-limiting step in the alternative pathway of bile acid synthesis in hepatocytes. STARD1 expression increases in ASH and NASH and determines the accumulation of cholesterol in mitochondria, which impacts the physico-chemical mitochondrial membranes properties and as a consequence impairs the activity of specific mitochondrial solute carriers, such as the 2-oxoglutarate carrier (2-OGC), limiting the exchange between cytosolic glutathione and mitochondrial 2-oxoglutarate (2-OG). Although HIF-1 is stabilized in hypoxia largely due to the requirement of prolylhydroxylases (PHDs) for oxygen to signal HIF degradation, PHDs are also dependent on 2-OG, and therefore it is conceivable that impairment of 2-OGC by STARD1-mediated cholesterol accumulation may contribute to HIF-1 stabilization due in part to decreased availability of cytosolic 2-OG. In this perspective, this review explores the interplay between HIF-1 stabilization and STARD1 induction and the potential contribution of this functional relationship to ASH and NASH

    Performance of compliant mechanisms applied to a modified shape accelerometer of single and double layer

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    Accelerometers are widely used in several mechanisms of high sensitivity. They are employed for example in tilt-control in spacecraft, inertial navigation, oil exploration, seismic monitoring, etc. In order to improve the sensitivity of the measurements, implementation of Displacement-amplifying Compliant Mechanisms (DaCMs) in a capacitive accelerometer have been reported in the literature. In this paper, a system composed of two elements; capacitive accelerometer with extended beams (CAEB) and a DaCM geometry, of single and souble layer, are analysed. Three materials were considered, in the case, for the second layer. The DaCM implementation improves the operation frequency and displacement sensitivity, under different proportions, at the same time. Furthermore, three sweeps were performed: a range of thickness from 25 µm up to 30 µm (to determine the appropriate silicon mass value, using SOI technology), a range of second layer thickness (to choose the more appropriate material and its thickness) and a range of gravity values (to determine the maximum normal stress in the beams, which defines the superior value of the g operation range). The in-plane mode (y-axis) was considered in all analysed cases. This characterization was developed using the Finite Element Method. Structural and modal analysis responses were under study

    Balancing the risks of hydraulic failure and carbon starvation : a twig scale analysis in declining Scots pine

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    Understanding physiological processes involved in drought-induced mortality is important for predicting the future of forests and for modelling the carbon and water cycles. Recent research has highlighted the variable risks of carbon starvation and hydraulic failure in drought-exposed trees. However, little is known about the specific responses of leaves and supporting twigs, despite their critical role in balancing carbon acquisition and water loss. Comparing healthy (non-defoliated) and unhealthy (defoliated) Scots pine at the same site, we measured the physiological variables involved in regulating carbon and water resources. Defoliated trees showed different responses to summer drought compared with non-defoliated trees. Defoliated trees maintained gas exchange while non-defoliated trees reduced photosynthesis and transpiration during the drought period. At the branch scale, very few differences were observed in non-structural carbohydrate concentrations between health classes. However, defoliated trees tended to have lower water potentials and smaller hydraulic safety margins. While non-defoliated trees showed a typical response to drought for an isohydric species, the physiology appears to be driven in defoliated trees by the need to maintain carbon resources in twigs. These responses put defoliated trees at higher risk of branch hydraulic failure and help explain the interaction between carbon starvation and hydraulic failure in dying trees.Peer reviewe

    Circulating concentrations of free triiodothyronine are associated with central adiposity and cardiometabolic risk factors in young euthyroid adults

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    Funding for open access charge: Universidad de Granada/CBUA. This study was funded by the Spanish Ministry of Economy and Competitiveness via the Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III (PI13/01393), by the Retos de la Sociedad program (DEP2016-79512-R), European Regional Development Funds (ERDF), the Spanish Ministry of Education (FPU13/04365), the Fundacion Iberoamericana de Nutricion (FINUT), the Redes Tematicas de Investigacion Cooperativa RETIC (Red SAMID RD16/0022), the AstraZeneca HealthCare Foundation, the University of Granada Plan Propio de Investigacion 2016-Excellence actions: Unit of Excellence on Exercise and Health (UCEES)-and Plan Propio de Investigacion 2018-the Programa Contratos-Puente and Contratos Perfeccionamiento de Doctores, the Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades (ERDF; ref. SOMM17/6107/UGR), and the Fundacion Alfonso Martin Escudero (grant awarded to GSD).Thyroid dysfunction is associated with classic cardiometabolic risk factors in humans. However, this relationship remains unclear in young euthyroid adults. The present work examines the associations of circulating thyroid hormones (THs) and thyroid-stimulating hormone (TSH) concentrations with body composition and cardiometabolic risk factors in young euthyroid adults. A total of 106 sedentary, euthyroid adults (72 women; 22 ± 2 years old) participated in this cross-sectional study. THs and TSH serum concentrations were determined in fasting conditions (6 h). Body composition (fat mass (FM), lean mass (LM), and visceral adipose tissue (VAT)) was determined by dual-energy X-ray absorptiometry, anthropometric parameters (weight, height, and waist circumference) were measured, and neck adipose tissue mass was quantified through computed tomography (CT) scanning. Cardiometabolic risk factors including fasting glucose and lipid metabolism markers, hepatic phosphatase and transaminases, and blood pressure were also assessed. Free triiodothyronine (FT3) concentration was positively associated with body mass index, LM, VAT, and waist circumference (all P ≤ 0.038). FT3 was also associated with glucose, insulin, HOMA-IR, fatty liver index, and blood pressure (all P < 0.024). All the associations were attenuated when adjusting for sex. In contrast, we found no associations of TSH or free thyroxine with any body composition parameter or cardiometabolic risk factors. In conclusion, FT3 is associated with central adiposity and cardiometabolic risk factors including insulin resistance, fatty liver index, and mean, systolic and diastolic blood pressure in young euthyroid adults. ClinicalTrials.gov identifier: NCT02365129.Universidad de Granada/CBUASpanish Government PI13/01393Retos de la Sociedad program DEP2016-79512-REuropean CommissionSpanish Government FPU13/04365Fundacion Iberoamericana de Nutricion (FINUT)Redes Tematicas de Investigacion Cooperativa RETIC Red SAMID RD16/0022AstraZenecaUniversity of Granada Plan Propio de Investigacion 2016-Excellence actions: Unit of Excellence on Exercise and Health (UCEES)Plan Propio de Investigacion 2018-the Programa Contratos-PuenteContratos Perfeccionamiento de DoctoresJunta de AndaluciaConsejeria de Conocimiento, Investigacion y Universidades (ERDF) SOMM17/6107/UGRFundacion Alfonso Martin Escuder
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