13,247 research outputs found
Mechanism for bipolar resistive switching in transition metal oxides
We introduce a model that accounts for the bipolar resistive switching
phenomenom observed in transition metal oxides. It qualitatively describes the
electric field-enhanced migration of oxygen vacancies at the nano-scale. The
numerical study of the model predicts that strong electric fields develop in
the highly resistive dielectric-electrode interfaces, leading to a spatially
inhomogeneous oxygen vacancies distribution and a concomitant resistive
switching effect. The theoretical results qualitatively reproduce non-trivial
resistance hysteresis experiments that we also report, providing key validation
to our model.Comment: Accepted for publication in Physical Review B, 6 twocolumn pages, 5
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DYRK1A: the double-edged kinase as a protagonist in cell growth and tumorigenesis
DYRK1A (dual-specificity tyrosine-regulated kinase 1A) is a kinase with multiple implications for embryonic development, especially in the nervous system where it regulates the balance between proliferation and differentiation of neural progenitors. The DYRK1A gene is located in the Down syndrome critical region and may play a significant role in the developmental brain defects, early neurodegeneration, and cancer susceptibility of individuals with this syndrome. DYRK1A is also expressed in adults, where it might participate in the regulation of cell cycle, survival, and tumorigenesis, thus representing a potential therapeutic target for certain types of cancer. However, the final readout of DYRK1A overexpression or inhibition depends strongly on the cellular context, as it has both tumor suppressor and oncogenic activities. Here, we will discuss the functions and substrates of DYRK1A associated with the control of cell growth and tumorigenesis with a focus on the potential use of DYRK1A inhibitors in cancer therapy.This study was supported by grants from Ministerio de Economía y Competitividad, Fondo de Investigación Sanitaria, PI12/00775 and from Ministerio de Economía y Competitividad, Red Temática de Investigación Cooperativa en Cancer (RD12/0036/0027) to PSG.S
A reference architecture for federating IoT infrastructures supporting semantic interoperability
: The Internet-of-Things (IoT) is unanimously identified as one of the main pillars of future smart scenarios. However, despite the growing number of IoT deployments, the majority of IoT applications tend to be self-contained, thereby forming vertical silos. Indeed, the ability to combine and synthesize data streams and services from diverse IoT platforms and testbeds, holds the promise to increase the potential of smart applications in terms of size, scope and targeted business context. This paper describes the system architecture for the FIESTA-IoT platform, whose main aim is to federate a large number of testbeds across the planet, in order to offer experimenters the unique experience of dealing with a large number of semantically interoperable data sources. This system architecture was developed by following the Architectural Reference Model (ARM) methodology promoted by the IoT-A project (FP7 “light house” project on Architecture for the Internet of Things). Through this process, the FIESTAIoT architecture is composed of a set of Views that deals with a “logical” functional decomposition (Functional View, FV) and data structuring and annotation, data flows and inter-functional component interactions (Information View, IV)
Development of a piezoelectric based energy harvesting system for autonomous wireless sensor nodes
Assessing the Influence of Salmon Farming through Total Lipids, Fatty Acids, and Trace Elements in the Liver and Muscle of Wild Saithe Pollachius virens
Saithe Pollachius virens are attracted to uneaten salmon feed underneath cages at open-cage salmon farms in Norway. The aggregated Saithe have modified their feeding habits as they have switched from wild prey to uneaten food pellets, which could lead to physiological and biochemical changes in the Saithe. Variations in profiles of total lipids, fatty acids, and trace elements in Saithe liver and muscle were measured to evaluate the influence of fish feed from salmon farms on wild Saithe populations. Farm-aggregated Saithe had higher fat content in liver tissues than did individuals captured more than 25 km away from farms, but no clear differences were found in muscle tissues. High proportions of fatty acids of terrestrial origin, such as oleic, linoleic, and linolenic acids, in liver and muscle tissues of farm-aggregated Saithe reflected the presence of wild Saithe at farms. Accordingly, low proportions of arachidonic, eicosapentaenoic, and docosahexaenoic acids in Saithe tissues mirrored the feeding activity at farms. Variations in specific trace element signatures among fish groups also revealed the farming influence on wild Saithe. High levels of Fe, As, Se, Zn, and B in liver, but also As, B, Li, Hg, and Sr in muscle of Saithe captured away from farms indicated the absence of feeding at farms.This study was part of the project “Evaluation of actions to promote sustainable coexistence between salmon culture and coastal fisheries – ProCoEx” funded by The Norwegian Seafood Research Fund (FHF). The study was also supported by the Norwegian Research Council through the EcoCoast project
Boyeria Irene (Fonscolombe, 1838) y Cordulegaster Boltonii (Donovan, 1807) (Odonata): Dos estrategias en cuanto a sustratos de emergencia de larvas en un mismo hábitat.
Se presentan datos sobre emergencia de Cordulegaster boltonii y Boyeria irene en un río de montaña del centro de España (altitud 1200 m s.n.m.) donde coexisten ambas especies, basados en la recogida semanal de exuvias. Boyeria irene comenzó a emerger 28 días más tarde que C. boltonii. Los sustratos usados por las larvas de ambas especies para emerger se solaparon ampliamente, aunque C. boltonii utilizó significativamente más árboles. Con respecto a otras zonas geográficas, las dos especies han modificado su estrategia, retrasando el inicio del periodo de emergencia. Se discute la importancia de las condiciones ambientales (sobre todo temperatura) en este hecho
Characterizing, modelling and understanding the climate variability of the deep water formation in the North-Western Mediterranean Sea
Observing, modelling and understanding the climate-scale variability of the deep water formation (DWF) in the North-Western Mediterranean Sea remains today very challenging. In this study, we first characterize the interannual variability of this phenomenon by a thorough reanalysis of observations in order to establish reference time series. These quantitative indicators include 31 observed years for the yearly maximum mixed layer depth over the period 1980–2013 and a detailed multi-indicator description of the period 2007–2013. Then a 1980–2013 hindcast simulation is performed with a fully-coupled regional climate system model including the high-resolution representation of the regional atmosphere, ocean, land-surface and rivers. The simulation reproduces quantitatively well the mean behaviour and the large interannual variability of the DWF phenomenon. The model shows convection deeper than 1000 m in 2/3 of the modelled winters, a mean DWF rate equal to 0.35 Sv with maximum values of 1.7 (resp. 1.6) Sv in 2013 (resp. 2005). Using the model results, the winter-integrated buoyancy loss over the Gulf of Lions is identified as the primary driving factor of the DWF interannual variability and explains, alone, around 50 % of its variance. It is itself explained by the occurrence of few stormy days during winter. At daily scale, the Atlantic ridge weather regime is identified as favourable to strong buoyancy losses and therefore DWF, whereas the positive phase of the North Atlantic oscillation is unfavourable. The driving role of the vertical stratification in autumn, a measure of the water column inhibition to mixing, has also been analyzed. Combining both driving factors allows to explain more than 70 % of the interannual variance of the phenomenon and in particular the occurrence of the five strongest convective years of the model (1981, 1999, 2005, 2009, 2013). The model simulates qualitatively well the trends in the deep waters (warming, saltening, increase in the dense water volume, increase in the bottom water density) despite an underestimation of the salinity and density trends. These deep trends come from a heat and salt accumulation during the 1980s and the 1990s in the surface and intermediate layers of the Gulf of Lions before being transferred stepwise towards the deep layers when very convective years occur in 1999 and later. The salinity increase in the near Atlantic Ocean surface layers seems to be the external forcing that finally leads to these deep trends. In the future, our results may allow to better understand the behaviour of the DWF phenomenon in Mediterranean Sea simulations in hindcast, forecast, reanalysis or future climate change scenario modes. The robustness of the obtained results must be however confirmed in multi-model studies
Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles. III. The Role of Sodium and the Head Echo Size on the Probability of Detection
We present a path forward on a long-standing issue concerning the flux of small and slow meteoroids, which are believed to be the dominant portion of the incoming meteoric mass flux into the Earth's atmosphere. Such a flux, which is predicted by dynamical dust models of the Zodiacal Cloud, is not evident in ground-based radar observations. For decades this was attributed to the fact that the radars used for meteor observations lack the sensitivity to detect this population, due to the small amount of ionization produced by slow-velocity meteors. Such a hypothesis has been challenged by the introduction of meteor head echo (HE) observations with High Power and Large Aperture radars, in particular the Arecibo 430 MHz radar. Janches et al. developed a probabilistic approach to estimate the detectability of meteors by these radars and initially showed that, with the current knowledge of ablation and ionization, such particles should dominate the detected rates by one to two orders of magnitude compared to the actual observations. In this paper, we include results in our model from recently published laboratory measurements, which showed that (1) the ablation of Na is less intense covering a wider altitude range; and (2) the ionization probability, βip for Na atoms in the air is up to two orders of magnitude smaller for low speeds than originally believed. By applying these results and using a somewhat smaller size of the HE radar target we offer a solution that reconciles these observations with model predictions
Tools for analyzing parallel I/O
Parallel application I/O performance often does not meet user expectations. Additionally, slight access pattern modifications may lead to significant changes in performance due to complex interactions between hardware and software. These issues call for sophisticated tools to capture, analyze, understand, and tune application I/O. In this paper, we highlight advances in monitoring tools to help address these issues. We also describe best practices, identify issues in measure- ment and analysis, and provide practical approaches to translate parallel I/O analysis into actionable outcomes for users, facility operators, and researchers
Valoración funcional en futbolistas y su utilidad en la recuperación tras una lesión
Aim - The objective of this study was to establish reference values for professional football players in a series of previously selected functional tests.
Methods - 42 professional football players were functionally assessed during two seasons (2012/13 and 2013/14), at three different times: preseason, midpoint of the season and end of the season. For this purpose, the following tests were carried out: Counter Movement Jump (bipodal jump), 5 metres Shuttle Run Sprint Test (speed/agility), Barrow Test (agility), Y Balance Test (posture control), Single Hop Test and Triple Hop Test (unipodal jump).
Results - The average obtained values were: Counter Movement Jump (40.25±4.13cm), 5 metres Shuttle Run Sprint Test (10.89±0.38 seconds), Barrow Test (7.46±0.27 seconds), right asymmetry Y Balance Test (4.63±2.16%), left asymmetry Y Balance Test (3.91±2.25%), right Single Hop Test (2.06±0.11 meters), left Single Hop Test (2.07±0.12 meters), right Triple Hop Test (6.87±0.29 meters) and left Triple Hop Test (6.83±0.31).
Conclusion - This paper contributes reference values which can be used to determine the sports performance or quantify the degree of functional recovery of an professional injured football player during his recovery.Objetivo – El objetivo del presente estudio consistió en establecer valores de referencia para futbolistas profesionales en una serie de test funcionales seleccionados previamente.
Método – Durante dos temporadas (2012/13 y 2013/14) y en tres momentos distintos de las mismas, 42 futbolistas profesionales fueron evaluados funcionalmente mediante las siguientes pruebas: CMJ (salto bipodal), 5 m Shuttle Run Sprint Test (velocidad/agilidad), Test de Barrow (agilidad), Y Balance Test (control postural), Single Hop Test y Triple Hop Test (salto unipodal).
Resultados – Los valores medios obtenidos fueron: CMJ (40.25±4.13cm), 5 m Shuttle Run Sprint Test (10.89±0.38 segundos), Test de Barrow (7.46±0.27 segundos), Y Balance asimetría derecha (4.63±2.16%), Y Balance asimetría izquierda (3.91±2.25%), Single Hop Test derecha (2.06±0.11 metros), Single Hop Test izquierda (2.07±0.12 metros), Triple Hop Test derecha (6.87±0.29 metros) y Triple Hop Test izquierda (6.83±0.31).
Conclusión – Este trabajo contribuye aportando valores de referencia que puedan ser utilizados para cuantificar el grado de recuperación funcional durante la recuperación de un futbolista profesional lesionado
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