561 research outputs found

    Development and validation of the Spanish hazard perception test

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    Objective: The aim of the current study is to develop and obtain validity evidence for a Hazard Perception test suitable for the Spanish driving population. To obtain validity evidence to support the use of the test, the effect of hazardous and quasi-hazardous situations on the participants’ Hazard Prediction is analysed and the pattern of results of drivers of different driving experience: learner, novice and expert drivers and re-offender vs. non-offender drivers, is compared. Potentially hazardous situations are those that develop without involving any real hazard (i.e., the driver didn’t actually have to decelerate or make any evasive manoeuvre to avoid a potential collision). The current study analysed multiple offender drivers attending compulsory re-education programmes as a result of reaching the maximum number of penalty points on their driving licence, due to repeated violations of traffic laws. Method: A new video-based hazard perception test was developed, using a total of 20 hazardous situation videos plus 8 quasi-hazardous situation videos. They were selected from 167 recordings of natural hazards in real Spanish driving settings

    A multi-agent system for managing adverse weather situations on the road network

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    The development of traffic management and control strategies to improve traffic flows and road safety is necessary due to the high dynamism of traffic flows. The use of distributed intelligent systems can help the traffic organizations and the road operators to cope with possible incidents on the road network, especially when the incidents are related to adverse meteorological conditions. In that case, the probability of road accidents is increased due to the difficulty of driving under bad weather conditions. So, if the operators detect any meteorological incident, they must decide how to deal with it in order to improve traffic safety. In this paper we introduce a new multiagent system (MAS) to support traffic management when there appear meteorological problems in the road network. MAS technology helps to deal with the specific characteristics of traffic domain. The proposed MAS is able to work in two ways: a) coordinately, where all the agents work to solve weather problems in large networks and b) locally, where due to communications breakdown small groups of agents work together to inform road users about weather problems. The MAS has a rule-based system to deal with the meteorological data and decide the actions to take in front of any meteorological issue. This expert system also controls the quality of the data, improving the road operator confidence in the decisions taken by the expert system. However, weather sensors can provide wrong data, due to several factors (hardware failure, climate factors, etc.) so the rule based system controls these provided data by applying specific coherence and correlation rules to improve the quality of the taken decisions

    Understanding the performance of an AnMBR treating urban wastewater and food waste via model simulation and characterization of the microbial population dynamics

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    [EN] An anaerobic membrane bioreactor (AnMBR) pilot plant treating kitchen food waste (FW) jointly with urban wastewater was run for 536 days. Different operational conditions were tested varying the sludge retention time (SRT), the hydraulic retention time (HRT) and the penetration factor (PF) of food waste disposers. COD removal efficiency exceeded 90% in all tested conditions. The joint treatment resulted in an almost 3-fold increase in methane production (at 70 days of SRT, 24 h HRT and 80% PF) in comparison with the treatment of urban wastewater only. Mathematical model simulations and Illumina technology were used to obtain in-depth information of this outstanding process performance. Both the PF and SRT factors increased influent biodegradability. The experimental results were accurately reproduced via model simulations modifying only the influent biodegradability. The high SRT and the presence of ground FW in the influent resulted in higher hydrolytic activity. Not only did the Archaea population increase 3-fold but Levilinea genera was also significantly raised. Three new genera characterised by anaerobic fermentation of amino acids (Leptolinea, Aminomonas and Aminobacterium) were among the ten most abundant of the total sequences identified during the joint treatment, indicating an improvement in the hydrolysis step of anaerobic degradation. Influent biodegradability remained at high values when FW addition stopped.This research work has been financially supported by the Generalitat Valenciana (PROMETEO/2012/029 PROJECT), which is gratefully acknowledged.Durán Pinzón, F.; Zamorano -López, N.; Barat, R.; Ferrer, J.; Aguado García, D. (2018). Understanding the performance of an AnMBR treating urban wastewater and food waste via model simulation and characterization of the microbial population dynamics. Process Biochemistry. 67:139-146. https://doi.org/10.1016/j.procbio.2018.02.010S1391466

    Flat plate solar collector performance using alumina nanofluids: Experimental characterization and efficiency tests

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    Solar energy has become an important renewable energy source for reducing the use of fossil fuels and to mitigate global warming, for which solar collectors constitute a technology that is to be promoted. The use of nanofluids can increase the efficiency of solar into thermal energy conversion in solar collectors. Experimental values for the specific heat, thermal conductivity and viscosity of alumina/water nanofluids are needed to evaluate the influence of the solid content (from 0.25 to 5 v%) and the flow rate on the Reynolds, Nusselt and the heat transfer coefficient. In the laminar flow regime, thermal conductivity enhancement over specific heat decrement is key parameter, and a 2.34% increase in the heat transfer coefficient is theoretically obtained for 1 v% alumina nanofluid. To corroborate the results, experimental tests were run in a flat plate solar collector. A reduction in efficiency from 47% to 41.5% and a decrease in the heat removal factor were obtained using the nanofluid due to the formation of a nanoparticle deposition layer adding an addition thermal resistance to heat transfer. Nanofluids are recommended only if the nanoparticle concentration is high enough to enhance thermal conductivity, but no so high so as to avoid wall deposition

    Social support and ambulatory blood pressure in older people

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    This is a non-final version of an article published in final form in Journal of Hypertension 34.10 (2016): 2045-2052. http://dx.doi.org/10.1097/HJH.0000000000001036Objective: Social support has been associated with greater nocturnal decline (dipping) in blood pressure (BP) in younger and middle-Aged individuals. However, it is uncertain if aggregated measures of social support are related to ambulatory SBP in older adults, where high SBP is frequent and clinically challenging. Methods: We studied 1047 community-living individuals aged at least 60 years in Spain. Twenty-four-hour ambulatory BP was determined under standardized conditions. Social support was assessed with a seven-item questionnaire on marital status, cohabitation, frequency of contact with relatives, or with friends and neighbors, emotional support, instrumental support, and outdoor companionship. A social support score was built by summing the values of the items that were significantly associated with SBP variables, such that the higher the score, the better the support. Results: Participants' mean age was 71.7 years (50.8% men). Being married, cohabiting, and being accompanied when out of home were the support items significantly associated with SBP variables. After adjustment for sociodemographic (age, sex, education), behavioral (BMI, alcohol, tobacco, salt consumption, physical activity, Mediterranean diet score), and clinical variables [sleep quality, mental stress, comorbidity, BP medication, and ambulatory BP levels and heart rate (HR)], one additional point in the social support score built with the abovementioned three support variables, was associated with a decrease of 0.93mmHg in night-Time SBP (P=0.039), totaling 2.8mmHg decrease for a score of 3 vs. 0. The three-item social support score was also inversely associated with the night/day SBP ratio (β=-0.006, P=0.010). Conclusion: In older adults, social support is independently associated with lower nocturnal SBP and greater SBP dipping. Further research is needed in prospective studies to confirm these resultsData collection was funded by Fondo de Investigacion Sanitaria (FIS) grants 09/1626 and 12/1166 (Ministry of Health of Spain and FEDER/FSE) and by the Catedra UAM de Epidemiologia y Control del Riesgo Cardiovascular. Specific funding for this analysis was obtained from FIS grant PI13/0232

    Influence of Food Waste addition over microbial communities in an Anaerobic Membrane Bioreactor plant treating urban wastewater

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    [EN] Notorious changes in microbial communities were observed during and after the joint treatment of wastewater with Food Waste (FW) in an Anaerobic Membrane Bioreactor (AnMBR) plant. The microbial population was analysed by high-throughput sequencing of the 16S rRNA gene and dominance of Chloroflexi, Firmicutes, Synergistetes and Proteobacteria phyla was found. The relative abundance of these potential hydrolytic phyla increased as a higher fraction of FW was jointly treated. Moreover, whereas Specific Methanogenic Activity (SMA) rose from 10 to 51 mL CH4 g(-1) VS, Methanosarcinales order increased from 34.0% over 80.0% of total Archaea, being Methanosaeta the dominant genus. The effect of FW over AnMBR biomass was observed during the whole experience, as methane production rose from 49.2 to 144.5 L CH4 . kg(-1) influent COD. Furthermore, biomethanization potential was increased over 82% after the experience. AnMBR technology allows the established microbial community to remain in the bioreactor even after the addition of FW, improving the anaerobic digestion of urban wastewater. (C) 2018 Elsevier Ltd. All rights reserved.This research work has been financially supported by the Generalitat Valenciana (PROMETEO/2012/029 PROJECT), which is gratefully acknowledged.Zamorano -López, N.; Moñino Amoros, P.; Borrás Falomir, L.; Aguado García, D.; Barat, R.; Ferrer, J.; Seco Torrecillas, A. (2018). Influence of Food Waste addition over microbial communities in an Anaerobic Membrane Bioreactor plant treating urban wastewater. Journal of Environmental Management. 217:788-796. https://doi.org/10.1016/j.jenvman.2018.04.018S78879621

    Online media landscape in Spain: a quantitative approach

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    As in other European countries, the online media have completed their first ten years in Spain. In this ftrst decade, the Spanish online publications have experienced a process of birth, development and consolidation of professional standards. Based on a quantitative methodology applied to a census of 1,274 online media, which was achieved by the research team in January 2005, this paper provides valuable data regarcling the degree of development reached by the Spanish online media. This research, carried out by professors from four universities (Navarre, Basque Country, Santiago de Compostela and Malaga), analyses such variables as the geographical distribution of online publications, media types and their contents, the correspondence with offline print and broadcast media, the linguistic diversity and the development of business models, among others

    Spreadsheet for the simulation of artificial neural networks (ANNs)

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    La utilización de Redes de Neuronas Artificiales (RNA) en problemas de predicción de series de tiempo, clasificación y reconocimiento de patrones ha aumentado considerablemente en los últimos años. Programas informáticos de matemáticas de propósito general tales como MATLAB, MATHCAD y aplicaciones estadísticas como SPSS y S-PLUS incorporan herramientas que permiten implementar RNAs. A esta oferta de software hay que añadir programas específicos como NeuralWare, EasyNN o Neuron. Desde un punto de vista educativo, el acceso de los estudiantes a estos programas puede ser difícil dado que no están pensadas como herramientas didácticas. Por otro lado, las hojas de cálculo como Excel y Gnumeric incorporan utilidades que permiten implementar RNAs y son de fácil acceso para los estudiantes. El objetivo de este trabajo es proporcionar un pequeño tutorial sobre la utilización de Excel para implementar una RNA que nos permita ajustar los valores de una serie de tiempo correspondiente a actividad cerebral alfa y que permita al alumno entender el funcionamiento de estos dispositivos de cálculo.In recent years, the use of Artificial Neural Networks or ANNs has increased considerably to solve prediction problems in time series, classification and recognition of patterns. General-purpose mathematical programs such as MATLAB, MATHCAD and mathematical and statistical programs such as SPSS and S-PLUS incorporate tools that allow the implementation of ANNs. In addition to these, specific programs such as NeuralWare, EasyNN, or Neuron, complete the software offer using ANNs. From an educational point of view, an aspect that concerns the authors of this work, student access to these programs can be expensive or, in sorne case, unadvisable given the few possibilities they provide as didactic instruments. These programs are usually easy to use but do not facilitate the understanding of the technique used. On the other hand, spreadsheets like Excel or Gnumeric incorporate tools that allow all of the necessary calculations to implement an ANN. These programs are user-friendly to the point that they are used by university laboratories, as well as psychology, economic science, and engineering students, to mention a few. This paper provides a small tutorial on the use of a spreadsheet, specifically Excel, to implement an ANN to adjust the values of a time series corresponding to cerebral alpha activity
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