83 research outputs found

    Estructura territorial y relaciones funcionales en el Corredor del Henares: una aproximación desde la movilidad diaria de la población

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    «Territorial structure and functional relations in the Henares Corridor: an approach from the daily population mobility». This article attempts to study the recent evolution of the population daily mobility with the goal of identifying the possible changes in the dependence relations of Henares Corridor with regard to the capital of Madrid, as well as recognizing the possible configuration of a functional sub-region between the municipalities. We began with the hypothesis that the recent organization of residential and productive spaces —specially manifesting in the outskirt of the metropolitan area of Madrid— has affected such relations. For this study we part from the information provided by the Domiciliary Mobility Surveys done by the Regional Transport Consortium of Madrid in 1988 and 1996.En este artículo se pretende estudiar la evolución reciente de la movilidad diaria de la población con el fin de identificar los posibles cambios en las relaciones de dependencia del Corredor del Henares respecto a Madrid capital, y también reconocer la posible configuración de una subregión funcional entre los municipios que lo componen. Se parte de la hipótesis de que los recientes procesos de reorganización de los espacios residenciales y productivos, especialmente manifiestos en las periferias del área metropolitana de Madrid, han afectado a dichas relaciones. El estudio se basa en la información proporcionada por las Encuestas Domiciliarias de Movilidad realizadas por el Consorcio Regional de Transportes de Madrid en 1988 y 1996

    Development and validation of a computational model for steak double-sided pan cooking

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    The objective of this study was to develop and validate a numerical model to adequately simulate the double-sided pan cooking of beef in a domestic environment. The proposed model takes into account the heat flow from the pan to the meat and the moisture transfer, simultaneously with the meat deformation. The model considers the swelling pressure gradient caused by the shrinkage of the meat fibers and connective tissue due to the denaturation of proteins and the loss of the water holding capacity during cooking. The model results were successfully verified with experimental data of the central temperature and weight loss recorded during cooking for three degrees of doneness. The measured experimental temperatures at the center of the meat were 30 ± 3 °C (very rare), 44 ± 3 °C (rare) and 57 ± 2 °C (done) for a 19 mm steak thickness. Meanwhile, their water losses were 4 ± 2 %, 8 ± 1 % and 11 ± 2 %, respectively. The root mean squared errors of the model predictions were 2.16 °C (very rare), 3.56 °C (rare) and 4.57 °C (done) for the central temperature and 1.48 %, 2.08 % and 2.40 %, respectively for the water loss. The model also correctly predicts cooking times for steaks of different thicknesses, taking weight loss as a reference to set this time. The proposed model is postulated as a useful cooking assistance tool to estimate the optimal cooking time according to consumer preferences

    How do university teachers use digital technologies in class?

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    [EN] The main goal of this article is the description of a peculiar textbook which aims to contribute in a friendly and available way to the teacher-student relationship in a subject devoted to the foundations of a discipline. Analytical Chemistry and Nanotechnology have been selected as case studies. The description of the true concept of innovation in the framework of Einstein and Khun thoughts, as well as the two approaches (top-down and bottom- up) to teach and learn the foundations of an area of knowledge is the subject matter of the Introduction of the paper. The so-named “textbook” is composed by two essential parts. On the one hand, a CD room contains 350 dynamic downloadable images (PowerPoint), and, on the other, a book containing the detailed explanation of each image and its dynamics, a glossary of terms and the detailed responses to 240 questions posed at the end of the chapters. The principal teaching-learning innovation consists of the major relative importance of the images versus the text, which is designed to support images. In this way, the roles of teachers and students are far from the traditional ones. Other innovations are as follows: the fact that an undergraduate student was a full co-author, the permanent cross references of the teaching message and the use of many examples from the real life. This innovation was successively extrapolated to an e-book devoted to the basic divulgation of nanotechnology to the citizens. This approach is subsequently described at the end of the article.[ES] En este artículo se describe una obra docente atípica, con intención de ser rompedora, orientada a contribuir de forma amigable y asequible a una innovación docente-discente de una materia universitaria dedicada a los fundamentos/principios de un área de conocimiento. Como “casos de estudio” se han utilizado la Química Analítica y la Nanotecnología. El contenido del artículo se contextualiza en el apartado Introducción del mismo donde se describe el concepto verdadero de innovación en el marco de los enfoques de Einstein y Khun, y se exponen las dos formas (top-down y bottom-up) de abordar la enseñanza-aprendizaje de los fundamentos de una área de conocimiento. La obra docente consta de un CD con aproximadamente 350 imágenes (descargables en PowerPoint ) con movimientos y un libro de texto que contiene la explicación detallada de cada diapositiva; así como dos anexos con un glosario de 250 términos y la resolución detallada de unas 240 cuestiones, respectivamente. La innovación docente-discente principal que aporta es que las imágenes tienen un mayor peso específico que el texto, lo que implica cambiar los roles del profesor y del estudiante en horas presenciales y no presenciales. Otras innovaciones a destacar son la participación de una estudiante como coautora, las referencias cruzadas permanentes para contextualizar al estudiante; así como el empleo permanente de ejemplos de la vida real y actual para apoyar los conceptos típicos de un libro de fundamentos. Esta innovación se ha extrapolado con éxito a un e-bookde divulgación de la nanotecnología a los ciudadanos, que también se describe sucintamente al final del artículo.Los autores desean mostrar su agradecimiento a la editorial de la Universidad de Córdoba, UCOPRESS, y especialmente a su director, Juan Pedro Monferrer, por la receptividad a estas dos propuestas atípicas (libro de texto y e-book), y su dedicación a superar los problemas que toda innovación (en este caso editorial) implica.González-Alfaya, M.; López-Jiménez, M.; López-Lorente, A.; Soriano Dotor, M.; Valcárcel, M. (2017). ¿Puede un libro de texto atípico inducir a la innovación docente-discente?. REDU. Revista de Docencia Universitaria. 15(2):295-314. doi:10.4995/redu.2017.7777SWORD29531415

    Theory of Current and Shot Noise Spectroscopy in Single-Molecular Quantum Dots with Phonon Mode

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    Using the Keldysh nonequilibrium Green function technique, we study the current and shot noise spectroscopy of a single molecular quantum dot coupled to a local phonon mode. It is found that in the presence of electron-phonon coupling, in addition to the resonant peak associated with the single level of the dot, satellite peaks with the separation set by the frequency of phonon mode appear in the differential conductance. In the ``single level'' resonant tunneling region, the differential shot noise power exhibit two split peaks. However, only single peaks show up in the ``phonon assisted'' resonant-tunneling region. An experimental setup to test these predictions is also proposed.Comment: 5 pages, 3 eps figures embedde

    Preparation and characterization of polymer composite materials based on PLA/TiO2 for antibacterial packaging

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    Polymer composite materials based on polylactic acid (PLA) filled with titanium dioxide (TiO2) nanoparticles were prepared. The aim of this work was to investigate the antibacterial action of TiO2 against a strain of E. coli (DH5) to obtain information on their potential uses in food and agro-alimentary industry. PLA/TiO2 systems were prepared by a two-step process: Solvent casting followed by a hot-pressing step. Characterization was done as a function of particle size (21 nm and <100 nm) and particle content (0%, 1%, 5%, 10%, and 20%, wt %). Structural characterization carried out by X-ray diffraction (XRD) and Fourier Transformed Infrared spectroscopy (FTIR) did not reveal significant changes in polymer structure due to the presence of TiO2 nanoparticles. Thermal characterization indicated that thermal transitions, measured by differential scanning calorimetry (DSC), did not vary, irrespective of size or content, whereas thermogravimetric analysis (TGA) revealed a slight increase in the temperature of degradation with particle content. Bacterial growth and biofilm formation on the surface of the composites against DH5 Escherichia coli was studied. Results suggested that the presence of TiO2 nanoparticles decreases the amount of extracellular polymeric substance (EPS) and limits bacterial growth

    Supervivencia del injerto tras trasplante hepático: aproximación a un nuevo índice de riesgo español

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    Introducción: existen diversos indicadores para la valoración de la supervivencia del injerto hepático (DRI americano y ET-DRI europeo, entre otros), pero existen diferencias importantes entre los programas de trasplante de los diferentes países y podría ser que dichos indicadores no sean válidos en nuestro medio. Objetivos: el objetivo de este estudio es describir un nuevo indicador nacional de riesgo del injerto hepático a partir de los resultados del Registro Español de Trasplante Hepático (RETH) y validar el DRI y el ET-DRI. Metodología: el RETH incluye un análisis de Cox de los factores relacionados con la supervivencia del injerto. En base a sus resultados se define el indicador graft risk index (GRI). Las variables que contempla dependen del proceso de donación: edad, causa de muerte, compatibilidad sanguínea y tiempo de isquemia fría; y del receptor: edad, enfermedad de base, virus C, número de trasplante, estado UNOS y técnica quirúrgica. Se obtuvo la curva de la regresión logística y se calcularon las curvas de supervivencia del injerto por estratificación. La precisión se evaluó mediante el área ROC. Resultados: un GRI de 1 se corresponde con una probabilidad de pérdida del injerto del 23, 25%; cada punto de aumento del GRI supone que la probabilidad se multiplica por 1, 33. El GRI mostró la mejor discriminación por estratificación. El área ROC del DRI fue 0, 54 (95% IC, 0, 50-0, 59) y del ET-DRI, 0, 56 (95% IC, 0, 51-0, 61), frente al GRI 0, 70 (95% IC, 0, 65-0, 73) (p < 0, 0001). Conclusiones: el DRI y el ET-DRI no parecen útiles en nuestro medio y sería necesario disponer de un indicador propio. El GRI requiere un estudio nacional que perfile más el indicador y realice una validación más amplia. Introduction: several indicators are available to assess liver graft survival, including the American DRI and the European ET-DRI. However, there are significant differences between transplant programs of different countries, and the previously mentioned indicators might be not valid in our setting. Objectives: the aim of the study was to describe a new national liver graft risk indicator based on the results obtained from the Registro Espanol de Trasplante Hepatico (RETH) and to validate the DRI and ET-DRI indicators. Methods: the RETH includes a Cox analysis of factors associated with graft survival; the graft risk index (GRI) indicator was defined based on these results. The variables considered are dependent upon the donation conditions (age, cause of death, blood compatibility and cold ischemia time) and the transplant recipient (age, underlying disease, hepatitis C virus, transplant number, UNOS status and surgical technique). A logistic regression curve was obtained and graft survival curves were calculated by stratification. Precision was assessed using the ROC analysis. Results: a GRI of 1 represents a probability of graft loss of 23.25%; each point increase in the GRI score multiplies this probability by 1.33. The best discrimination of GRI was obtained by stratification.The DRI ROC area was 0.54 (95% CI, 0.50-0.59) and the ET-DRI ROC area was 0.56 (95% CI, 0.51-0.61), compared to 0.70 (95% CI, 0.65-0.73) (p < 0.0001) for the GRI. Conclusions: both the DRI and ET-DRI do not seem to be useful in our setting. Hence a national indicator is more desirable.The GRI requires a national study in order to further streamline and assess this indicator

    A framework for modelling the biomechanical behaviour of the human liver during breathing in real time using machine learning

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    Progress in biomechanical modelling of human soft tissue is the basis for the development of new clinical applications capable of improving the diagnosis and treatment of some diseases (e.g. cancer), as well as the surgical planning and guidance of some interventions. The finite element method (FEM) is one of the most popular techniques used to predict the deformation of the human soft tissue due to its high accuracy. However, FEM has an associated high computational cost, which makes it difficult its integration in real-time computer-aided surgery systems. An alternative for simulating the mechanical behaviour of human organs in real time comes from the use of machine learning (ML) techniques, which are much faster than FEM. This paper assesses the feasibility of ML methods for modelling the biomechanical behaviour of the human liver during the breathing process, which is crucial for guiding surgeons during interventions where it is critical to track this deformation (e.g. some specific kind of biopsies) or for the accurate application of radiotherapy dose to liver tumours. For this purpose, different ML regression models were investigated, including three tree-based methods (decision trees, random forests and extremely randomised trees) and other two simpler regression techniques (dummy model and linear regression). In order to build and validate the ML models, a labelled data set was constructed from modelling the deformation of eight ex-vivo human livers using FEM. The best prediction performance was obtained using extremely randomised trees, with a mean error of 0.07 mm and all the samples with an error under 1 mm. The achieved results lay the foundation for the future development of some real-time software capable of simulating the human liver deformation during the breathing process during clinical interventions.This work has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO) through research projects TIN2014-52033-R and DPI2013-40859-R, both also supported by European FEDER funds. The authors acknowledge the kind collaboration of the personnel from the hospital involved in the research.Lorente, D.; Martínez-Martínez, F.; Rupérez Moreno, MJ.; Lago, MA.; Martínez-Sober, M.; Escandell-Montero, P.; Martínez-Martínez, JM.... (2017). A framework for modelling the biomechanical behaviour of the human liver during breathing in real time using machine learning. Expert Systems with Applications. 71:342-357. doi:10.1016/j.eswa.2016.11.037S3423577

    Variation in the dispersions of powder liquid ratios in hand-mix glass ionomers

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    BACKGROUND: The Powder/Liquid Ratio (PLR) influence, and the literature regarding the handling and physical properties of Glass Ionomer restorative materials (GIC) were investigated. OBJECTIVE: The objective of the study was to compare the PLR variability and magnitude in hand-mix GICs, as dispensed for clinical use. From the recorded individual powder and liquid weights, additional comparisons could be made by pairing the various “extreme” outer observations in relation to the manufacturer’s PLR. STUDY DESIGN: The materials assessed were Ketac Universal Hand-mix (KUH), Riva Self Cure Hand-mix (RSCH) and Fuji IX GP Hand-mix (FIXH). Twenty scoops of powder were paired with twenty drops of liquid, as would be the case in the clinical scenario. Statistical analysis was completed with the Kruskal Wallis H test, Intraclass Correlation (ICC) and straight line regressions with One-way ANOVA and the post-hoc Tukey HSD Test (p<0.05 was considered significant). RESULTS: The powder and liquid observations indicate a lack of consistency in both the powder and liquid dispersions. The volume remained “one drop” but the weights were much lower than the manufacturer’s recommended drop weight for some observations, due to air in the liquid drop. The Kruskal-Wallis H test indicated significant differences (p=0.0001) between the three materials for the paired PLRs. The One-way ANOVA and post-hoc Tukey HSD Test were used to compare the recommended PLR to the results and the significant differences (p<0.01). CONCLUSION: The recommended manufacturers’ powder and liquid weights were KUH 0.150/0.05g; RSC 0.165/0.035; FIXH 0.18/0.05, respectively. KUH, FIXH and RSCH liquid had powder and liquid dispersions above the manufacturer’s recommendations. FIXH had the most paired PLR observations within the ±10% range followed by KUH. Extreme powder and liquid combinations could occur in the clinical scenario and these combinations were considered

    Analysis of initial stabilization of cell efficiency in amorphous silicon photovoltaic modules under real outdoor conditions

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    [EN] This contribution presents a field study in which the initial stabilization of thin-film amorphous silicon (a-Si:H) is investigated. Two grid-connected a-Si:H photovoltaic plants have been monitored and analyzed under real outdoor conditions. A per-unit approach is proposed to compare PV plants with differences in their electrical characteristic and the start-up date. The representation of a normalized per unit PV power versus the accumulated incoming irradiation reveals an evolution that can be characterized through an exposure-response function. By this function, two populations of defects in the cells are detected. It is found that the stabilization process in the first year of operation produces a decrease of 10% in the peak power, equivalent to a decrease of 0.5% in cell efficiency. The use of the accumulated PSH for conducting the analysis of the initial stabilization produces similarities that cannot be obtained if a time scale is used. These results provide a powerful tool for PV plant designers because they enable a prediction to be made of the time-scale stabilization response in terms of unitary power, correlated with the peak sun hours received. (C) 2017 Elsevier Ltd. All rights reserved.This work was supported by Generalitat Valenciana (PROM-ETEOII/2014/059) and Spanish MINECO (Ministry of Economy and Competitiveness TEC2014-53727-C2-1-R).Mateo-Guerrero, C.; Hernández Fenollosa, MDLÁ.; Montero Reguera, ÁE.; Segui-Chilet, S. (2018). Analysis of initial stabilization of cell efficiency in amorphous silicon photovoltaic modules under real outdoor conditions. Renewable Energy. 120:114-125. https://doi.org/10.1016/j.renene.2017.12.054S11412512

    Effectiveness of an mHealth intervention combining a smartphone app and smart band on body composition in an overweight and obese population: Randomized controlled trial (EVIDENT 3 study)

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    Background: Mobile health (mHealth) is currently among the supporting elements that may contribute to an improvement in health markers by helping people adopt healthier lifestyles. mHealth interventions have been widely reported to achieve greater weight loss than other approaches, but their effect on body composition remains unclear. Objective: This study aimed to assess the short-term (3 months) effectiveness of a mobile app and a smart band for losing weight and changing body composition in sedentary Spanish adults who are overweight or obese. Methods: A randomized controlled, multicenter clinical trial was conducted involving the participation of 440 subjects from primary care centers, with 231 subjects in the intervention group (IG; counselling with smartphone app and smart band) and 209 in the control group (CG; counselling only). Both groups were counselled about healthy diet and physical activity. For the 3-month intervention period, the IG was trained to use a smartphone app that involved self-monitoring and tailored feedback, as well as a smart band that recorded daily physical activity (Mi Band 2, Xiaomi). Body composition was measured using the InBody 230 bioimpedance device (InBody Co., Ltd), and physical activity was measured using the International Physical Activity Questionnaire. Results: The mHealth intervention produced a greater loss of body weight (–1.97 kg, 95% CI –2.39 to –1.54) relative to standard counselling at 3 months (–1.13 kg, 95% CI –1.56 to –0.69). Comparing groups, the IG achieved a weight loss of 0.84 kg more than the CG at 3 months. The IG showed a decrease in body fat mass (BFM; –1.84 kg, 95% CI –2.48 to –1.20), percentage of body fat (PBF; –1.22%, 95% CI –1.82% to 0.62%), and BMI (–0.77 kg/m2, 95% CI –0.96 to 0.57). No significant changes were observed in any of these parameters in men; among women, there was a significant decrease in BMI in the IG compared with the CG. When subjects were grouped according to baseline BMI, the overweight group experienced a change in BFM of –1.18 kg (95% CI –2.30 to –0.06) and BMI of –0.47 kg/m2 (95% CI –0.80 to –0.13), whereas the obese group only experienced a change in BMI of –0.53 kg/m2 (95% CI –0.86 to –0.19). When the data were analyzed according to physical activity, the moderate-vigorous physical activity group showed significant changes in BFM of –1.03 kg (95% CI –1.74 to –0.33), PBF of –0.76% (95% CI –1.32% to –0.20%), and BMI of –0.5 kg/m2 (95% CI –0.83 to –0.19). Conclusions: The results from this multicenter, randomized controlled clinical trial study show that compared with standard counselling alone, adding a self-reported app and a smart band obtained beneficial results in terms of weight loss and a reduction in BFM and PBF in female subjects with a BMI less than 30 kg/m2 and a moderate-vigorous physical activity level. Nevertheless, further studies are needed to ensure that this profile benefits more than others from this intervention and to investigate modifications of this intervention to achieve a global effect
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