1,886 research outputs found

    Sobre el método de Andrea Palladio para la realización del éntasis

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    A theoretical quantum study of the electronic properties of mentoxy dichloro phosphorous (C10H19OPCl2)

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    Indexación: Scopus.A theoretical quantum study of the organophosphorus compound with formula C10H19OPCl2 (MEPCL2) was carried out. The results of the calculations show excellent agreement between experimental and computed frequencies evaluated at the B3LYP/6-311++G(d,p) level of theory. A study of the electronic properties, such as excitation energies and wavelengths were performed employing the time-dependent DFT (TD-DFT) method. Global a chemical reactivity of MEPCL2 was analyzed through global reactivity descriptors, while its local reactivity was analyzed by mean maps of the electrostatic potential. Also, the orbital energies values suggest that a charge transfer is occurring within the molecule. © 2018 American Physical Society.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072018000103887&lng=en&nrm=iso&tlng=e

    Monte Carlo simulations of post-common-envelope white dwarf + main sequence binaries: comparison with the SDSS DR7 observed sample

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    Detached white dwarf + main sequence (WD+MS) systems represent the simplest population of post-common envelope binaries (PCEBs). Since the ensemble properties of this population carries important information about the characteristics of the common-envelope (CE) phase, it deserves close scrutiny. However, most population synthesis studies do not fully take into account the effects of the observational selection biases of the samples used to compare with the theoretical simulations. Here we present the results of a set of detailed Monte Carlo simulations of the population of WD+MS binaries in the Sloan Digital Sky Survey (SDSS) Data Release 7. We used up-to-date stellar evolutionary models, a complete treatment of the Roche lobe overflow episode, and a full implementation of the orbital evolution of the binary systems. Moreover, in our treatment we took into account the selection criteria and all the known observational biases. Our population synthesis study allowed us to make a meaningful comparison with the available observational data. In particular, we examined the CE efficiency, the possible contribution of internal energy, and the initial mass ratio distribution (IMRD) of the binary systems. We found that our simulations correctly reproduce the properties of the observed distribution of WD+MS PCEBs. In particular, we found that once the observational biases are carefully taken into account, the distribution of orbital periods and of masses of the WD and MS stars can be correctly reproduced for several choices of the free parameters and different IMRDs, although models in which a moderate fraction (<=10%) of the internal energy is used to eject the CE and in which a low value of CE efficiency is used (<=0.3) seem to fit better the observational data. We also found that systems with He-core WDs are over-represented in the observed sample, due to selection effects.Comment: 15 pages, 7 figures, accepted for publication in A&

    Phase Transitions in Confined Antiferromagnets

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    Review and analysis of vehicle stability models during floods and proposal for future improvements

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    This is the peer reviewed version of the following article: Bocanegra, RA, Vallés-Morán, FJ, Francés, F. Review and analysis of vehicle stability models during floods and proposal for future improvements. J Flood Risk Management. 2020; 13 ( Suppl. 1):e12551, which has been published in final form at https://doi.org/10.1111/jfr3.12551. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Flood water can affect vehicles significantly, which in turn can increase the negative effects of floods as vehicles are washed away by the flow and become a form of debris. In cities, most fatalities during floods occur inside vehicles. Consequently, it is necessary to establish thresholds for vehicle stability during this type of event to provide information necessary for flood risk management. This article analyses the available stability models developed over recent years to determine such thresholds. The stability models were grouped according to the way in which they approached car watertightness and the stability thresholds proposed by each of them were compared. It was found that these thresholds vary over a relatively wide range. Additionally, the experimental data were compared with the results provided by these studies leading to the conclusion that several of the stability models analysed do not fit measured data well. New research is required to overcome the simplifications made by the state-of-the-art models and to try to standardise the decision criteria which should be adopted to define stability thresholds for vehicles of different characteristics.Departamento Administrativo de Ciencia, Tecnologia e Innovacion COLCIENCIAS (Colombia) call 728-2015; Spanish Ministry of Science and Innovation through the research project TETISCHANGE, Grant/Award Number: RTI2018-093717-B-I00.Bocanegra, RA.; Vallés-Morán, FJ.; Francés, F. (2020). Review and analysis of vehicle stability models during floods and proposal for future improvements. Journal of Flood Risk Management. 13:1-13. https://doi.org/10.1111/jfr3.12551S11313Arrighi, C., Alcèrreca-Huerta, J. C., Oumeraci, H., & Castelli, F. (2015). Drag and lift contribution to the incipient motion of partly submerged flooded vehicles. Journal of Fluids and Structures, 57, 170-184. doi:10.1016/j.jfluidstructs.2015.06.010Arrighi C. Castelli F. &Oumeraci H.(2016). Effects of flow orientation on the onset of motion of flooded vehicles. InProceedings of the 4th IAHR Europe Congress. Liege DOI:https://doi.org/10.1201/b21902-140.Arrighi, C., Huybrechts, N., Ouahsine, A., Chassé, P., Oumeraci, H., & Castelli, F. (2016). Vehicles instability criteria for flood risk assessment of a street network. Proceedings of the International Association of Hydrological Sciences, 373, 143-146. doi:10.5194/piahs-373-143-2016Bonham A. J. &Hattersley R. T.(1967).Low level causeways. WRL Report No. 100. University of New South Wales. Sydney Australia.Cox R. J. Shand T. D. &Blacka M. J.(2010). Appropriate safety criteria for people in floods.Australian Rainfall and Runoff. WRL Research Report 240. Report for Institution of Engineers Australia.DROBOT, S., BENIGHT, C., & GRUNTFEST, E. (2007). Risk factors for driving into flooded roads. Environmental Hazards, 7(3), 227-234. doi:10.1016/j.envhaz.2007.07.003FitzGerald, G., Du, W., Jamal, A., Clark, M., & Hou, X.-Y. (2010). Flood fatalities in contemporary Australia (1997-2008). Emergency Medicine Australasia, 22(2), 180-186. doi:10.1111/j.1742-6723.2010.01284.xGordon A. D. &Stone P. B.(1973).Car stability on road causeways. WRL Technical Report No. 73/12. University of New South Wales. Sydney Australia.Jonkman, S. N., & Kelman, I. (2005). An Analysis of the Causes and Circumstances of Flood Disaster Deaths. Disasters, 29(1), 75-97. doi:10.1111/j.0361-3666.2005.00275.xKellar, D. M. M., & Schmidlin, T. W. (2012). Vehicle-related flood deaths in the United States, 1995-2005. Journal of Flood Risk Management, 5(2), 153-163. doi:10.1111/j.1753-318x.2012.01136.xKeller R. J. &Mitsch B.(1993).Safety aspects of the design of roadways as floodways. Research Report No. 69 Urban Water Research Association of Australia.Kramer, M., Terheiden, K., & Wieprecht, S. (2016). Safety criteria for the trafficability of inundated roads in urban floodings. International Journal of Disaster Risk Reduction, 17, 77-84. doi:10.1016/j.ijdrr.2016.04.003Martínez-Gomariz, E., Gómez, M., Russo, B., & Djordjević, S. (2016). Stability criteria for flooded vehicles: a state-of-the-art review. Journal of Flood Risk Management, 11, S817-S826. doi:10.1111/jfr3.12262Martínez-Gomariz, E., Gómez, M., Russo, B., & Djordjević, S. (2017). A new experiments-based methodology to define the stability threshold for any vehicle exposed to flooding. Urban Water Journal, 14(9), 930-939. doi:10.1080/1573062x.2017.1301501Mens M. J. Erlich M. Gaume E. Lumbroso D. Moreda Y. Van der VatM. &Versini P. A.(2008).Frameworks for flood event management. Report Number T19‐07‐03. WL Delft Hydraulics. Delft Netherlands.Moore, K. A., & Power, R. K. (2002). Safe Buffer Distances for Offstream Earth Dams. Australasian Journal of Water Resources, 6(1), 1-15. doi:10.1080/13241583.2002.11465206Oshikawa H. &Komatsu T.(2014). Study on the risk evaluation for a vehicular traffic in a flood situation.Proceedings of the 19th IAHR‐APD Congress Hanoi Vietnam.Pregnolato, M., Ford, A., Wilkinson, S. M., & Dawson, R. J. (2017). The impact of flooding on road transport: A depth-disruption function. Transportation Research Part D: Transport and Environment, 55, 67-81. doi:10.1016/j.trd.2017.06.020Shand T. Cox R. Blacka M. &Smith G.(2011).Australian Rainfall and Runoff (AR&R). Appropriate safety criteria for vehicles. Australian rainfall and runoff revision project 10: Report Number: P10/S2/020. Sidney Australia.Shu, C., Xia, J., Falconer, R. A., & Lin, B. (2011). Incipient velocity for partially submerged vehicles in floodwaters. Journal of Hydraulic Research, 49(6), 709-717. doi:10.1080/00221686.2011.616318Smith G. P. Davey E. K. &Cox R. J.(2014).Flood hazard. WRL Technical Report 2014/07. University of New South Wales. Sydney Australia.Smith G. P. Modra B. D. Tucker T. A. &Cox R. J.(2017).Vehicle stability testing for flood flows. WRL Technical Report 2017/07. University of New South Wales. Sydney Australia.Suarez, P., Anderson, W., Mahal, V., & Lakshmanan, T. R. (2005). Impacts of flooding and climate change on urban transportation: A systemwide performance assessment of the Boston Metro Area. Transportation Research Part D: Transport and Environment, 10(3), 231-244. doi:10.1016/j.trd.2005.04.007Teo, F. Y., Xia, J., Falconer, R. A., & Lin, B. (2012). Experimental studies on the interaction between vehicles and floodplain flows. 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Natural Hazards, 58(1), 1-14. doi:10.1007/s11069-010-9639-

    O papel das atribuizons causais e as metas académicas nos procesos de aprendizaxe do alumnado galego de formación profesional

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    [Resumo] As atribuizóns causais do rendimento, mediante as que o alunado outorga a certos tipos de causas a responsabilidade dos seus éxitos e fracasos, determinan en grande medida a motivación e a conduta de rendimento dos escolares. Pola sua parte, as metas académicas definen-se como conxuntos de crenzas, atribuizóns e afectos que regulan e dirixen a intención da conduta e en tal sentido implican formas diferentes de achegar-se, comprometer- se e responder as actividades de logro académico. Dnhas e outras veñen de ser estudadas entre o alunado galego de formación profesional de grau médio (a etapa que, xunto ao bacharelato, conforma o ensino secundário pós-obrigatório). Ternos encontrado que as atribuizóns controlábeis e internas (como a capacidade e o esforzo) son os determinantes máis significativos tanto do enfoque de aprendizaxe orientado ao significado e acomprensión como da procura de metas de aprendizaxe, o que a sua vez se corresponde coa obten- ción dun rendimento xeralmente alto; mentres que as atribuizáns incontrolábeis e externas (como a sorte, a facilidade das matérias ou o profesorado) exercen unha importante influéncia na determinación do enfoque de aprendizaxe orientado a reprodución e da procura de metas de reforzo social, ao tempo que se corresponden coa obtención de baixos níveis de rendimento.[Abstract] The causal attributions of academic performance, trough which secondary students concede a certain type of causes the liability for their successes and failures, determines to a great extent, students motivation and academic performace. On the side, the academic golas are defined as a set of beiefs, attributions and affections that control and leed behaviour purposes, its in that sense, that it involves different approachable methos like commitment and respond to academic activities of achievement. Causal attributions, as well as academic goals have been studied among technical colleges students Galicia and the conclusions shows, that inward causal attributions (as the capacity/ability and effort) are the most significative deterrents 10 a leaming approach orientated to meaning and comprehension, as to the pursuit of objectives in leaming that at the same time results in obtaining good academic performance. However, the causal attributions incontrollable (as luc k, subjects and teacher's easiness) produce an important influence on leaming approaches orientated to reproduction and the search for supportive social goals corresponding at the same time with low academic performance levels

    Analysis of the relevance of a 3D virtual programme to detect drug use behaviors and bullyng

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    p. 20The psychometric data of a new computer science tool of three-dimensional simulation (3D) designed for the detection of risk of drug taking behaviours and bullying in adolescents is presented. In partic- ular, Mii School (the name of this new program), recreates 17 conflicting situations of drug use and bullying, where the participant must respond when they are immersed in different situations of risk. The computer program has shown good reliability properties (α=.802) and validity (showing a facto- rial structure composed of 8 factors that explain 57.26% of the total variance). The study is con- ducted on the basis of differently realised studies: One discusses the capacity and utility of the pro- gram as a tool of detection of behaviours of drug consumption and bullying in young people, as well as the potential applicability of this program in educative contextsS
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