241 research outputs found

    Substrate-induced enhancement of the chemical reactivity in metal-supported graphene

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    Graphene is commonly regarded as an inert material. However, it is well known that the presence of defects or substitutional hetero-atoms confers graphene promising catalytic properties. In this work, we use first-principles calculations to show that it is also possible to enhance the chemical reactivity of a graphene layer by simply growing it on an appropriate substrate. Our comprehensive study demonstrates that, in strongly interacting substrates like Rh(111), graphene adopts highly rippled structures that exhibit areas with distinctive chemical behaviors. According to the local coupling with the substrate, we find areas with markedly different adsorption, dissociation and diffusion pathways for both molecular and atomic oxygen, including a significant change in the nature of the adsorbed molecular and dissociated states, and a dramatic reduction (∼60%) of the O2dissociation energy barrier with respect to free-standing graphene. Our results show that the graphene-metal interaction represents an additional and powerful handle to tailor the graphene chemical properties with potential applications to nano patterning, graphene functionalization and sensing devicesWe thank the financial support from the Spanish MINECO (projects MAT2014-54484-P, MDM-2014-0377, MAT2016-77852-C2-2-R (AEI/FEDER, UE) and MAT2017-83273-R (AEI/FEDER,UE)). Computer time provided by the Spanish Supercomputer Network (RES) at the Magerit (CesViMa, Madrid) and Altamira (IFCA, Santander) supercomputers. CRM is grateful to the FPI-UAM graduate scholarship program and to Fundación Universia for financial suppor

    Recognition of facial expression of emotions in Parkinson’s disease: a theoretical review

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    Introducción. La expresión facial emocional constituye una guía básica en la interacción social y, por ello, las alteraciones en su expresión o reconocimiento suponen una importante limitación para la comunicación. Objetivo. Examinar las capacidades de reconocimiento de expresiones faciales y su posible deterioro en la enfermedad de Parkinson. Desarrollo. En primer lugar, se revisan las investigaciones sobre este tema y que no han encontrado resultados totalmente afines. En segundo lugar, se analizan los factores que pueden explicar estas divergencias y, en particular, como tercer objetivo, se valora la relación entre los problemas en el reconocimiento emocional y el deterioro cognitivo asociado a la enfermedad. Por último, se proponen estrategias alternativas para el desarrollo de estudios que contribuyan a clarificar el estado de estas habilidades en la enfermedad de Parkinson. Conclusiones. La mayoría de los estudios indica deficiencias en el reconocimiento de expresiones, sobre todo en las de contenido emocional negativo. No obstante, es posible que dichas alteraciones estén relacionadas con las que también aparecen en otros procesos perceptivos y ejecutivos propios de la enfermedad. Para avanzar en esta cuestión, consideramos necesario diseñar estudios sobre reconocimiento emocional que impliquen diferencialmente a los procesos cognitivos mencionados o que contrasten la ejecución de los individuos con estímulos no emocionales y con expresiones faciales. Además de incrementar nuestro conocimiento sobre las consecuencias funcionales del deterioro cerebral característico de la enfermedad, estos estudios pueden indicarnos si debe prestarse atención adicional a su rehabilitación dentro de los programas que se aplicanEmotional facial expression is a basic guide during social interaction and, therefore, alterations in their expression or recognition are important limitations for communication. Aim. To examine facial expression recognition abilities and their possible impairment in Parkinson’s disease. Development. First, we review the studies on this topic which have not found entirely similar results. Second, we analyze the factors that may explain these discrepancies and, in particular, as third objective, we consider the relationship between emotional recognition problems and cognitive impairment associated with the disease. Finally, we propose alternatives strategies for the development of studies that could clarify the state of these abilities in Parkinson’s disease. Conclusions. Most studies suggest deficits in facial expression recognition, especially in those with negative emotional content. However, it is possible that these alterations are related to those that also appear in the course of the disease in other perceptual and executive processes. To advance in this issue, we consider necessary to design emotional recognition studies implicating differentially the executive or visuospatial processes, and/or contrasting cognitive abilities with facial expressions and non emotional stimuli. The precision of the status of these abilities, as well as increase our knowledge of the functional consequences of the characteristic brain damage in the disease, may indicate if we should pay special attention in their rehabilitation inside the programs implementedProyecto ref. PSI2009-09067, financiado por el Ministerio de Ciencia e Innovación

    Nurses’ Health Risk Perception on the Influence of Professional and Personal Time Management: A Cross-Sectional Descriptive Study

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    Occupational health risk selfperception among nurses is linked to professional time management and well-being. In contrast, most of the activities done during personal time seem to have a visibly low effect on the subjects. The importance of time management in nurses’ regular work shifts and the relevance of harmonizing personal and family life with each professional’s particular circumstances are highlighted

    Increased plasma soluble endoglin levels as an indicator of cardiovascular alterations in hypertensive and diabetic patients

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    <p>Abstract</p> <p>Background</p> <p>Endoglin is involved in the regulation of endothelial function, but there are no studies concerning its relation with hypertension- and diabetes-associated pathologies. Thus, we studied the relationship between plasma levels of soluble endoglin and cardiovascular alterations associated with hypertension and diabetes.</p> <p>Methods</p> <p>We analyzed 288 patients: 64 with type 2 diabetes, 159 with hypertension and 65 healthy patients. We assessed the relationship of soluble endoglin plasma levels measured by enzyme-linked immunosorbent assay with basal glycemia, glycosylated hemoglobin, blood pressure, endothelial dysfunction (assessed by pressure wave velocity), hypertensive retinopathy (by Keith-Wagener classification), left ventricular hypertrophy (by Cornell and Sokolow indexes), cardiovascular risk and target organ (heart, vascular, kidney) damage.</p> <p>Results</p> <p>There are significant correlations between endoglin and glycemia, systolic blood pressure, pulse pressure, pressure wave velocity and electrocardiographically assessed left ventricular hypertrophy. Endoglin levels were significantly higher in patients with diabetes who had nondipper and extreme dipper circadian blood pressure patterns than in dipper circadian patterns, in patients with hypertension and diabetes who had riser pattern than in the other patients, and in patients with diabetes but not hypertension who had extreme dipper pattern than in dipper, nondipper and riser groups. There was also a significant correlation between plasma-soluble endoglin and lower levels of systolic night-day ratio. Higher endoglin levels were found in patients with diabetes who had retinopathy, in patients with diabetes who had a high probability of 10-year cardiovascular risk, and in patients with diabetes and hypertension who had three or more damaged target organs (heart, vessels, kidney) than in those with no organs affected.</p> <p>Conclusions</p> <p>This study shows that endoglin is an indicator of hypertension- and diabetes-associated vascular pathologies as endothelial dysfunction and cardiovascular damage.</p

    Tug-of-war between corrugation and binding energy: revealing the formation of multiple moiré patterns on a strongly interacting graphene-metal system

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    The formation of multidomain epitaxial graphene on Rh(111) under ultra-high vacuum (UHV) conditions has been characterized by scanning tunnelling microscopy (STM) measurements and density functional theory (DFT) calculations. At variance with the accepted view for strongly interacting graphene-metal systems, we clearly demonstrate the formation of different rotational domains leading to multiple moiré structures with a wide distribution of surface periodicities. Experiments reveal a correlation between the STM apparent corrugation and the lattice parameter of the moiré unit cell, with corrugations of just 30-40 pm for the smallest moirés. DFT calculations for a relevant selection of these moiré patterns show much larger height differences and a non-monotonic behaviour with the moiré size. Simulations based on non-equilibrium Green's function (NEGF) methods reproduce quantitatively the experimental trend and provide a detailed understanding of the interplay between electronic and geometric contributions in the STM contrast of graphene systems. Our study sheds light on the subtle energy balance among strain, corrugation and binding that drives the formation of the moiré patterns in all graphene/metal systems and suggests an explanation for the success of an effective model only based on the lattice mismatch. Although low values of the strain energy are a necessary condition, it is the ability of graphene to corrugate in order to maximize the areas of favourable graphene-metal interactions that finally selects the stable configurationsWe acknowledge financial support from Spanish grants MAT2013-41636-P, MAT2011-23627, MAT2011-26534, CSD2010-00024 (MINECO, Spain) and S2009/MAT-1467 (CAM, Spain). A.J.M.G. was supported by a Marie Curie action under the Seventh Framework Programme. P.P. was supported by the Ramón y Cajal Progra

    Predicting kill sites of an apex predator from GPS data in different multi‐prey systems

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    Kill rates are a central parameter to assess the impact of predation on prey species. An accurate estimation of kill rates requires a correct identification of kill sites, often achieved by field-checking GPS location clusters (GLCs). However, there are potential sources of error included in kill-site identification, such as failing to detect GLCs that are kill sites, and misclassifying the generated GLCs (e.g., kill for nonkill) that were not field checked. Here, we address these two sources of error using a large GPS dataset of collared Eurasian lynx (Lynx lynx), an apex predator of conservation concern in Europe, in three multiprey systems, with different combinations of wild, semidomestic, and domestic prey. We first used a subsampling approach to investigate how different GPS-fix schedules affected the detection of GLC-indicated kill sites. Then, we evaluated the potential of the random forest algorithm to classify GLCs as nonkills, small prey kills, and ungulate kills. We show that the number of fixes can be reduced from seven to three fixes per night without missing more than 5% of the ungulate kills, in a system composed of wild prey. Reducing the number of fixes per 24 h decreased the probability of detecting GLCs connected with kill sites, particularly those of semidomestic or domestic prey, and small prey. Random forest successfully predicted between 73%–90% of ungulate kills, but failed to classify most small prey in all systems, with sensitivity (true positive rate) lower than 65%. Additionally, removing domestic prey improved the algorithm’s overall accuracy. We provide a set of recommendations for studies focusing on kill-site detection that can be considered for other large carnivore species in addition to the Eurasian lynx. We recommend caution when working in systems including domestic prey, as the odds of underestimating kill rates are higher

    Management de recursos humanos y sistemas de información

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    Ponencia premiada en el Seminario que sobre el tema "Management de Recursos Humanos y Sistemas de Información" se ha organizado por el Instituto de Dirección y Organización de Empresas de la Universidad de Alcalá de Henares y de la empresa SAP, el día 2 de octubre de 1990

    Management de recursos humanos y sistemas de información

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    Ponencia premiada en el Seminario que sobre el tema "Management de Recursos Humanos y Sistemas de Información" se ha organizado por el Instituto de Dirección y Organización de Empresas de la Universidad de Alcalá de Henares y de la empresa SAP, el día 2 de octubre de 1990

    Seasonal and intradaily variations of Parietaria pollen in the atmosphere of Málaga.

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    Parietaria pollen is one of the main causes of hay fever and asthma in the population, presenting a high allergenicity. That is why, in order to inform the population, it is important to determine whether its behaviour pattern is different in different parts of the city. The objective of this study was to analyze and compare the behaviour pattern of the Parietaria pollen type in two different points within the city of Malaga and to analyze the existing correlation between pollen concentrations and the main meteorological parameters. We used two Hirst-type volumetric pollen traps, one of them installed in the periphery and the other in the city center, between 2017 and 2019. The samples were mounted and counted following the recommendations of the Spanish Aerobiology Network. To calculate the annual pollen integral, the sum of the mean daily concentrations throughout the year was used. To calculate the intradaily variations, the values were accumulated every two hours, expressed as percentages of the daily total. In order to study the relationships between meteorological parameters and pollen concentrations, Spearman correlation tests have been carried out. The values of the annual pollen integral were always much higher in the centre. Daily mean concentrations showed the presence of this pollen type in the atmosphere throughout the year. Regarding the intraday pattern, a more pronounced peak was observed in the city centre, while in the periphery, the distribution is more homogeneous throughout the day. The meteorological parameters play an important role in determining the daily concentrations in the atmosphere. In the light of these results, we can conclude that it is necessary to install several sampling points within the same city, due to its heterogeneity and different land uses, in order to inform the population with a greater precision and, in this way, prevent respiratory allergies.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Combining nitrogen substitutional defects and oxygen intercalation to control the graphene corrugation and doping level

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    By means of Scanning Tunneling Microscopy (STM) experiments and first-principles calculations, we demonstrate the synergetic effect of the combination of two different strategies to modify the properties of graphene supported on a strongly interacting substrate like Rh. A complete control of the corrugation and doping level is achieved combining the introduction of nitrogen defects and oxygen intercalation. Firstly, we show how to use ion bombardment to obtain purely-substitutional N-doped graphene on Rh(111) with tunable dopant concentration. In a second step, the interaction with the substrate is controlled by the amount of intercalated oxygen atoms. Unlike weakly interacting substrates, the highly corrugated structure of G/Rh(111) leads to remarkable variations of the electronic properties associated with nitrogen defects created in the high and low areas of the moiré. After oxygen intercalation, the N-doped graphene layer decouples from the substrate preserving the incorporated nitrogen atoms, which display a subtle dependence of the STM contrast. First–principles calculations confirm the identification of substitutional N-defects and the recovery of the Dirac cone with a tunable shift governed by the nitrogen concentration. Our results support the combination of different modification techniques to tailor structural and electronic properties of graphene and other 2D materialsWe thank the financial support from AEI and FEDER under project MAT2016-77852-C2-2-R (AEI/FEDER, UE) and from MINECO under projects CSD2010-00024, MAT2014-54484-P and MDM-2014-0377. CRM is grateful to FPI-UAM graduate scholarship program and Fundación Universia for financial suppor
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