1,003 research outputs found

    Una asignatura on-line de Historia de los Algoritmos

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    This paper describes the objectives, contents learning methodology and results of an on-line course about History of Algorithms for engineering students of the Polytechnic University of Madrid. This course is conducted in a virtual environment based on Moodle, with an educational model centered at student which includes a detailed planning of learning activities. . Our experience indicates that this subject is is highly motivating for students and the virtual environment facilitates competencies development

    Nueva medida y umbrales para la desigualdad y su relación con la conflictividad

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    This paper develops an alternative methodology to analyze income inequality and its structure. The proposed approach allows us, among other things, to classify individuals into income groups endogenously. This classification of income groups will be used to study the structure of inequality and to find a relation between inequality and conflict and social unrest. This approach is applied to Spanish income data from the Income and Living Conditions survey (SILC) conducted by the INE. We refer to the years 2005, 2007, 2009 and 2011 with the aim of evaluating the impact of the economic crisis. The empirical results show an increase in inequality and a decrease in the share of total income of households classified as poor, lower middle class and middle class. On the contrary, the households located at the right end of the income distribution scale have improved. This fact leads to a more unstable society and one prone to conflict.En este trabajo se desarrolla una metodología alternativa para analizar la desigualdad de la renta y su estructura. El procedimiento que se propone permite, entre otros, clasificar a los individuos en grupos de renta de forma endógena. Los grupos de renta resultantes facilitan el estudio de la estructura de la desigualdad y a su vez permiten relacionar la desigualdad con la posible generación de conflicto. El procedimiento desarrollado se aplica a datos de renta de los hogares españoles procedentes de la Encuesta de Condiciones de Vida (ECV) elaborada y publicada por el Instituto Nacional de Estadística. Se han utilizado datos correspondientes a los años 2005, 2007, 2009 y 2011 con el objeto de evaluar los efectos de la crisis en términos de distribución de renta. Los resultados ponen de manifiesto la creciente desigualdad de la renta y la disminución en la participación en el total de la renta de los hogares catalogados como pobres, clase media baja y clase media en beneficio de los hogares mejor posicionados. Esta situación conlleva a sociedades más inestables y propensas al conflicto

    Receptiveness of Spanish and flamenco professional dancers in their training and development

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    The concept of coaching is an important object of study in the development of sports coaches, and the relationship between athletes and coaches may define the professional life of the former. In the area of dance, the figure of the coach is represented by teachers, choreographers and directors; however, there are few studies that analyse the different forms of coaching and receptiveness in the training of dance professionals. Therefore, the aim of this study was to ascertain the receptiveness of professional Spanish dance and flamenco dancers to the coaching abilities of their respective teachers, directors or choreographers. The sample consisted of 143 dancers, 96 women (67.1%) and 47 men (32.9%) aged between 18 and 51 (30.52±7.86), who were students in their last year of a Higher Degree, or professionals from different companies specialising in Spanish dance and flamenco. The most relevant results show that there were significant statistical differences in receptiveness to coaching according to age, with the older dancers showing less receptiveness. Similarly, there were significant statistical differences according to the company in which the dancers carried out their professional work

    Evaluation of the Risk of Anxiety and/or Depression during Confinement Due to COVID-19 in Central Spain

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    Producción CientíficaAbstract: (1) Background: The confinement of the population in response to the COVID-19 pandemic was related to an increased risk of suffering from anxiety and/or depression in previous studies with other populations. (2) Methods: descriptive study using surveys (Goldberg Anxiety and Depression Scale) with 808 participants over 18 years of age between 14 and 20 of May 2020 during the confinement due to the SARS-CoV-2 virus in Spain. (3) Results: 63% of the participants were at risk of suffering from anxiety and 64.9% were at risk of depression. Variables reaching statistical significance were: age (t anxiety = −0.139 and t depression = −0.153), gender (t anxiety = −4.152 and t depression = −4.178), marital status (anxiety F = 2.893 and depression F = 3.011), symptoms compatible with COVID-19 (t anxiety = −4.177 and t depression = −3.791), previous need for psychological help (t anxiety = −5.385 and t depression = −7.136) and need for such help at the time of the study (t anxiety = −9.144 and depression = −10.995). In addition, we generated two regression models that estimate the risk of anxiety and depression. (4) Conclusions: more than half of the participants were at risk of suffering from anxiety and/or depression, confirming the negative effect of confinement on the populationDepartamento de Enfermería de la Universidad de Valladoli

    An Online Course on the History of Algorithms.

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    This paper describes the objectives, content, learning methodology and results of an online course on the History of Algorithms for engineering students at Polytechnic University of Madrid (UPM). This course is conducted in a virtual environment based on Moodle, with a student-centred educational model which includes a detailed planning of learning activities. Our experience indicates that this subject is highly motivating for students and the virtual environment facilitates competencies developmen

    A numerical study of the effect of nozzle diameter on diesel combustion ignition and flame stabilization

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    This is the author's version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087419864203.[EN] The role of nozzle diameter on diesel combustion is studied by performing computational fluid dynamics calculations of Spray A and Spray D from the Engine Combustion Network. These are well-characterized single-hole sprays in a quiescent environment chamber with thermodynamic conditions representative of modern diesel engines. First, the inert spray evolution is described with the inclusion of the concept of mixing trajectories and local residence time into the analysis. Such concepts enable the quantification of the mixing rate, showing that it decreases with the increase in nozzle diameter. In a second step, the reacting spray evolution is studied focusing on the local heat release rate distribution during the auto-ignition sequence and the quasi-steady state. The capability of a well-mixed-based and a flamelet-based combustion model to predict diesel combustion is also assessed. On one hand, results show that turbulence-chemistry interaction has a profound effect on the description of the reacting spray evolution. On the other hand, the mixing rate, characterized in terms of the local residence time, drives the main changes introduced by the increase of the nozzle diameter when comparing Spray A and Spray D.The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: The work was partially funded by the Government of Spain through the CHEST Project (TRA2017-89139-C2-1-R) and by Universitat Politecnica de Valencia through the Programa de Ayudas de Investigaciony Desarrollo (PAID-01-16).Desantes Fernández, JM.; García-Oliver, JM.; Novella Rosa, R.; Pachano-Prieto, LM. (2020). A numerical study of the effect of nozzle diameter on diesel combustion ignition and flame stabilization. International Journal of Engine Research. 21(1):101-121. https://doi.org/10.1177/1468087419864203S101121211Pickett, L. M., & Siebers, D. L. (2002). An investigation of diesel soot formation processes using micro-orifices. Proceedings of the Combustion Institute, 29(1), 655-662. doi:10.1016/s1540-7489(02)80084-0Pickett, L. M., & Siebers, D. L. (2005). Orifice Diameter Effects on Diesel Fuel Jet Flame Structure. Journal of Engineering for Gas Turbines and Power, 127(1), 187-196. doi:10.1115/1.1760525Du, C., Andersson, S., & Andersson, M. (2018). Two-dimensional measurements of soot in a turbulent diffusion diesel flame: the effects of injection pressure, nozzle orifice diameter, and gas density. Combustion Science and Technology, 190(9), 1659-1688. doi:10.1080/00102202.2018.1461850Ishibashi, R., & Tsuru, D. (2016). An optical investigation of combustion process of a direct high-pressure injection of natural gas. Journal of Marine Science and Technology, 22(3), 447-458. doi:10.1007/s00773-016-0422-xPang, K. M., Jangi, M., Bai, X.-S., Schramm, J., & Walther, J. H. (2017). Effects of Nozzle Diameter on Diesel Spray Flames: A numerical study using an Eulerian Stochastic Field Method. Energy Procedia, 142, 1028-1033. doi:10.1016/j.egypro.2017.12.350Pickett, L. M., Manin, J., Genzale, C. L., Siebers, D. L., Musculus, M. P. B., & Idicheria, C. A. (2011). Relationship Between Diesel Fuel Spray Vapor Penetration/Dispersion and Local Fuel Mixture Fraction. SAE International Journal of Engines, 4(1), 764-799. doi:10.4271/2011-01-0686García-Oliver, J. M., Malbec, L.-M., Toda, H. B., & Bruneaux, G. (2017). A study on the interaction between local flow and flame structure for mixing-controlled Diesel sprays. Combustion and Flame, 179, 157-171. doi:10.1016/j.combustflame.2017.01.023Dahms, R. N., Paczko, G. A., Skeen, S. A., & Pickett, L. M. (2017). Understanding the ignition mechanism of high-pressure spray flames. Proceedings of the Combustion Institute, 36(2), 2615-2623. doi:10.1016/j.proci.2016.08.023Gimeno, J., Martí-Aldaraví, P., Carreres, M., & Peraza, J. E. (2018). Effect of the nozzle holder on injected fuel temperature for experimental test rigs and its influence on diesel sprays. International Journal of Engine Research, 19(3), 374-389. doi:10.1177/1468087417751531Matusik, K. E., Duke, D. J., Kastengren, A. L., Sovis, N., Swantek, A. B., & Powell, C. F. (2017). High-resolution X-ray tomography of Engine Combustion Network diesel injectors. International Journal of Engine Research, 19(9), 963-976. doi:10.1177/1468087417736985Pandurangi, S. S., Bolla, M., Wright, Y. M., Boulouchos, K., Skeen, S. A., Manin, J., & Pickett, L. M. (2016). Onset and progression of soot in high-pressure n-dodecane sprays under diesel engine conditions. International Journal of Engine Research, 18(5-6), 436-452. doi:10.1177/1468087416661041Aubagnac-Karkar, D., Michel, J.-B., Colin, O., & Darabiha, N. (2017). Combustion and soot modelling of a high-pressure and high-temperature Dodecane spray. International Journal of Engine Research, 19(4), 434-448. doi:10.1177/1468087417714351Ihme, M., Ma, P. C., & Bravo, L. (2018). Large eddy simulations of diesel-fuel injection and auto-ignition at transcritical conditions. International Journal of Engine Research, 20(1), 58-68. doi:10.1177/1468087418819546Yue, Z., & Reitz, R. D. (2017). An equilibrium phase spray model for high-pressure fuel injection and engine combustion simulations. International Journal of Engine Research, 20(2), 203-215. doi:10.1177/1468087417744144Bhattacharjee, S., & Haworth, D. C. (2013). Simulations of transient n-heptane and n-dodecane spray flames under engine-relevant conditions using a transported PDF method. Combustion and Flame, 160(10), 2083-2102. doi:10.1016/j.combustflame.2013.05.003Pei, Y., Hawkes, E. R., & Kook, S. (2013). Transported probability density function modelling of the vapour phase of an n-heptane jet at diesel engine conditions. Proceedings of the Combustion Institute, 34(2), 3039-3047. doi:10.1016/j.proci.2012.07.033Pang, K. M., Jangi, M., Bai, X.-S., Schramm, J., & Walther, J. H. (2018). Modelling of diesel spray flames under engine-like conditions using an accelerated Eulerian Stochastic Field method. Combustion and Flame, 193, 363-383. doi:10.1016/j.combustflame.2018.03.030D’Errico, G., Lucchini, T., Contino, F., Jangi, M., & Bai, X.-S. (2014). Comparison of well-mixed and multiple representative interactive flamelet approaches for diesel spray combustion modelling. Combustion Theory and Modelling, 18(1), 65-88. doi:10.1080/13647830.2013.860238Kösters, A., Karlsson, A., Oevermann, M., D’Errico, G., & Lucchini, T. (2015). RANS predictions of turbulent diffusion flames: comparison of a reactor and a flamelet combustion model to the well stirred approach. Combustion Theory and Modelling, 19(1), 81-106. doi:10.1080/13647830.2014.982342Lucchini, T., D’Errico, G., Onorati, A., Frassoldati, A., Stagni, A., & Hardy, G. (2017). Modeling Non-Premixed Combustion Using Tabulated Kinetics and Different Fame Structure Assumptions. SAE International Journal of Engines, 10(2), 593-607. doi:10.4271/2017-01-0556Pal, P., Keum, S., & Im, H. G. (2015). Assessment of flamelet versus multi-zone combustion modeling approaches for stratified-charge compression ignition engines. International Journal of Engine Research, 17(3), 280-290. doi:10.1177/1468087415571006Pope, S. B. (1978). An explanation of the turbulent round-jet/plane-jet anomaly. AIAA Journal, 16(3), 279-281. doi:10.2514/3.7521Novella, R., García, A., Pastor, J. M., & Domenech, V. (2011). The role of detailed chemical kinetics on CFD diesel spray ignition and combustion modelling. Mathematical and Computer Modelling, 54(7-8), 1706-1719. doi:10.1016/j.mcm.2010.12.048CONVERGE manual. Madison, WI: Convergent Science, 2016.Yao, T., Pei, Y., Zhong, B.-J., Som, S., Lu, T., & Luo, K. H. (2017). A compact skeletal mechanism for n-dodecane with optimized semi-global low-temperature chemistry for diesel engine simulations. Fuel, 191, 339-349. doi:10.1016/j.fuel.2016.11.083Perez E. Application of a flamelet-based combustion model to diesel-like reacting sprays. Unpublished PhD Thesis, Universitat Politècnica de València, Valencia, 2019.Peters, N. (2000). Turbulent Combustion. doi:10.1017/cbo9780511612701Naud, B., Novella, R., Pastor, J. M., & Winklinger, J. F. (2015). RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF. Combustion and Flame, 162(4), 893-906. doi:10.1016/j.combustflame.2014.09.014Payri, R., García-Oliver, J. M., Xuan, T., & Bardi, M. (2015). A study on diesel spray tip penetration and radial expansion under reacting conditions. Applied Thermal Engineering, 90, 619-629. doi:10.1016/j.applthermaleng.2015.07.042Narayanaswamy, K., Pepiot, P., & Pitsch, H. (2014). A chemical mechanism for low to high temperature oxidation of n-dodecane as a component of transportation fuel surrogates. Combustion and Flame, 161(4), 866-884. doi:10.1016/j.combustflame.2013.10.012Kahila, H., Wehrfritz, A., Kaario, O., Ghaderi Masouleh, M., Maes, N., Somers, B., & Vuorinen, V. (2018). Large-eddy simulation on the influence of injection pressure in reacting Spray A. Combustion and Flame, 191, 142-159. doi:10.1016/j.combustflame.2018.01.004Pang, K. M., Jangi, M., Bai, X.-S., Schramm, J., Walther, J. H., & Glarborg, P. (2019). Effects of ambient pressure on ignition and flame characteristics in diesel spray combustion. Fuel, 237, 676-685. doi:10.1016/j.fuel.2018.10.020Tagliante, F., Poinsot, T., Pickett, L. M., Pepiot, P., Malbec, L.-M., Bruneaux, G., & Angelberger, C. (2019). 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    Trypanosomatids topoisomerase re-visited. New structural findings and role in drug discovery

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    AbstractThe Trypanosomatidae family, composed of unicellular parasites, causes severe vector-borne diseases that afflict human populations worldwide. Chagas disease, sleeping sickness, as well as different sorts of leishmaniases are amongst the most important infectious diseases produced by Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp., respectively. All these infections are closely related to weak health care services in low-income populations of less developed and least economically developed countries. Search for new therapeutic targets in order to hit these pathogens is of paramount priority, as no effective vaccine is currently in use against any of these parasites. Furthermore, present-day chemotherapy comprises old-fashioned drugs full of important side effects. Besides, they are prone to produce tolerance and resistance as a consequence of their continuous use for decades. DNA topoisomerases (Top) are ubiquitous enzymes responsible for solving the torsional tensions caused during replication and transcription processes, as well as in maintaining genomic stability during DNA recombination. As the inhibition of these enzymes produces cell arrest and triggers cell death, Top inhibitors are among the most effective and most widely used drugs in both cancer and antibacterial therapies. Top relaxation and decatenation activities, which are based on a common nicking–closing cycle involving one or both DNA strands, have been pointed as a promising drug target. Specific inhibitors that bind to the interface of DNA-Top complexes can stabilize Top-mediated transient DNA breaks. In addition, important structural differences have been found between Tops from the Trypanosomatidae family members and Tops from the host. Such dissimilarities make these proteins very interesting for drug design and molecular intervention. The present review is a critical update of the last findings regarding trypanosomatid’s Tops, their new structural features, their involvement both in the physiology and virulence of these parasites, as well as their use as promising targets for drug discovery

    On Estimating the Headcount Index by Using the Logistic Regression Estimator

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    The problem of estimating a proportion has important applications in the field of economics, and in general, in many areas such as social sciences. A common application in economics is the estimation of the headcount index. In this paper, we define the general headcount index as a proportion. Furthermore, we introduce a new quantitative method for estimating the headcount index. In particular, we suggest to use the logistic regression estimator for the problem of estimating the headcount index. Assuming a real data set, results derived from Monte Carlo simulation studies indicate that the logistic regression estimator can be more accurate than the traditional estimator of the headcount index

    Identification and conservation of remnant genetic resources of brown trout in relict populations from Western Mediterranean streams

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    This is a post-peer-review, pre-copyedit version of an article published in Hydrobiologia. The final authenticated version is available online at: https://doi.org/10.1007/s10750-012-1402-8Brown trout is a cold-adapted freshwater species with restricted distribution to headwater streams in rivers of the South European peninsulas, where populations are highly vulnerable because Mediterranean regions are highly sensitive to the global climatic warming. Moreover, these populations are endangered due to the introgressive hybridization with cultured stocks. Individuals from six remnant populations in Western Mediterranean rivers were sequenced for the complete mitochondrial DNA control region and genotyped for 11 nuclear markers. Three different brown trout lineages were present in the studied region. Significant genetic divergence was observed among locations and a strong effect of genetic drift was suggested. An important stocking impact (close to 25%) was detected in the zone. Significant correlations between mitochondrial-based rates of hatchery introgression and water flow variation suggested a higher impact of stocked females in unstable habitats. In spite of hatchery introgression, all populations remained highly differentiated, suggesting that native genetic resources are still abundant. However, climatic predictions indicated that suitable habitats for the species in these rivers will be reduced and hence trout populations are highly endangered and vulnerable. Thus, management policies should take into account these predictions to design upstream refuge areas to protect remnant native trout in the regionThis study has been supported by the Generalitat Valenciana Autonomous Government (Spain) project (2008/CI446)S

    TMA Vessel Segmentation Based on Color and Morphological Features: Application to Angiogenesis Research

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    Given that angiogenesis and lymphangiogenesis are strongly related to prognosis in neoplastic and other pathologies and that many methods exist that provide different results, we aim to construct a morphometric tool allowing us to measure different aspects of the shape and size of vascular vessels in a complete and accurate way. The developed tool presented is based on vessel closing which is an essential property to properly characterize the size and the shape of vascular and lymphatic vessels. The method is fast and accurate improving existing tools for angiogenesis analysis. The tool also improves the accuracy of vascular density measurements, since the set of endothelial cells forming a vessel is considered as a single object
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