510 research outputs found
Characterisation of apple cider cultivars by chemometric techniques using data from high-performance liquid chromatography and flow-injection analysis
Analytical techniques (HPLC and flow-injection analysis) for determining sugars, organic acids, polyphenols and pectins in apples, were employed along with chemometrics in the ripening and classification studies of cider apples. The use of principal component analysis allowed the authors to reduce the dimensionality of the data matrix; three new variables were obtained that accounted for 76% of variance. The projection of the apple cultivars in the reduced space allowed us to visualize the data structure on the basis of the degree of ripening and technological characteristics of the cider apple varieties monitored. Linear discriminant analysis computed a canonical variable with a prediction capacity of 93%, using three groups for cancellation in order to validate the method. The use of modelling techniques, such as SIMCA and partial least squares made an adequate grouping of apple cultivars feasible on the basis of their degree of ripening
Soft tissue tumors: Liposarcoma: Myxoid liposarcoma
Review on Soft tissue tumors: Liposarcoma: Myxoid liposarcoma, with data on clinics, and the genes involved
Modelling of continuous elastic systems by using the Finite Element Method
Propagation of mechanical waves in unidimensional systems is a fundamental part of physics, necessary for learning subjects such as acoustics and vibrations. The vibration of transverse waves in strings is the easiest case of elastic system. Usually, this is the first continuous elastic system in which students apply fundamental mathematical concepts as vibration mode, equation of motion and boundary condition. In this work the use of simulation methods is proposed to reinforce the understanding of vibratory and acoustic simple phenomena. This will be applied to the case of a string, a beam and a membrane of finite length with different physical characteristics and boundary conditions
Modelling of continuous elastic systems byusing the Finite Element Method
[EN] Propagation of mechanical waves in unidimensional systems is a fundamental part of physics, necessaryfor learning subjects such as acoustics and vibrations. The vibration of transverse waves in strings isthe easiest case of elastic system. Usually, this is the rst continuous elastic system in which studentsapply fundamental mathematical concepts as vibration mode, equation of motion and boundary condition.In this work the use of simulation methods is proposed to reinforce the understanding of vibratory andacoustic simple phenomena. This will be applied to the case of a string, a beam and a membrane of nitelength with di erent physical characteristics and boundary condition[ES] La propagación de ondas mecánicas en sistemas unidimensionales es una parte fundamental de la física, necesaria para el aprendizaje de asignaturas como acústica y vibraciones. La vibración de ondas transversales en cuerdas es el caso más sencillo de sistema elástico. Habitualmente, este es el primer sistema elástico continuo en el cual los alumnos aplican conceptos matemáticos fundamentales como modo de vibración, ecuación de movimiento y condición de contorno. En este trabajo se propone el uso de los métodos de simulación para reforzar la comprensión de fenómenos simples en acústica y vibraciones. Lo aplicaremos a los casos de cuerda vibrante, barras y membranas de longitud finita con diferentes características físicas y condiciones de contornoHerrero-Durá, I.; Picó, R.; Sánchez-Morcillo, V.; Garcia-Raffi, L. (2017). Modelización de sistemas elásticos continuos mediante el Método de Elementos Finitos. Modelling in Science Education and Learning. 10(2):193-202. doi:10.4995/msel.2017.7659SWORD193202102Giere, R. N. (1988). Explaining Science. doi:10.7208/chicago/9780226292038.001.0001Gilbert, S. W. (1991). Model building and a definition of science. Journal of Research in Science Teaching, 28(1), 73-79. doi:10.1002/tea.3660280107Tomasi, J. (1988). Models and modeling in theoretical chemistry. Journal of Molecular Structure: THEOCHEM, 179(1), 273-292. doi:10.1016/0166-1280(88)80128-3Gobert, J. D., & Buckley, B. C. (2000). Introduction to model-based teaching and learning in science education. International Journal of Science Education, 22(9), 891-894. doi:10.1080/095006900416839Gilbert, J. K. (2004). Models and Modelling: Routes to More Authentic Science Education. International Journal of Science and Mathematics Education, 2(2), 115-130. doi:10.1007/s10763-004-3186-4Kinzl, M., Schwiedrzik, J., Zysset, P. K., & Pahr, D. H. (2013). An experimentally validated finite element method for augmented vertebral bodies. Clinical Biomechanics, 28(1), 15-22. doi:10.1016/j.clinbiomech.2012.09.008Kabir, K. M. M., Matthews, G. I., Sabri, Y. M., Russo, S. P., Ippolito, S. J., & Bhargava, S. K. (2016). Development and experimental verification of a finite element method for accurate analysis of a surface acoustic wave device. Smart Materials and Structures, 25(3), 035040. doi:10.1088/0964-1726/25/3/035040Yu, C.-C., Chu, J. P., Jia, H., Shen, Y.-L., Gao, Y., Liaw, P. K., & Yokoyama, Y. (2017). Influence of thin-film metallic glass coating on fatigue behavior of bulk metallic glass: Experiments and finite element modeling. Materials Science and Engineering: A, 692, 146-155. doi:10.1016/j.msea.2017.03.071Oladejo K.A., Abu R. and Adewale M.D. (2012). Effective Modeling and Simulation of Engineering Problems with COMSOL Multiphysics. International Journal of Science and Technology 2(10), 742-748.Kinsler L.E., Frey A.R., Coppens A.B. and Sanders J.V. (2000). Fundamentals of Acoustics (4th ed.). United States of America: John Wiley & Sons, Inc
Online vs. classroom learning : examining motivational and self-regulated learning strategies among vocational education and training students
Ajut RecerCaixa 2017ACUP00129Numerous studies have been conducted to explore students' employment of motivational and self-regulated learning strategies (SRL). Research highlights the importance of having motivated students equipped with strategies that help them self-regulate their learning, this being highly important when learning is acquired through online learning programs. Nonetheless, such research has been scarce with Vocational Education and Training (VET) students; this is the gap in the literature this paper aims to address. The article analyzes the degree to which VET students employ motivational and SRL strategies by comparing them according to the learning mode chosen. To achieve this, a quantitative approach was adopted to carry out a cross-sectional study. A total of 577 first-year VET students responded to an online questionnaire based on some of the motivational and SRL strategies scale included in Pintrich's model. Statistical analyses were applied to test two hypotheses. Pintrich's model was validated through a confirmatory factor analysis considering its application to Catalan VET students for the first time. The results reveal significant differences between classroom and online students in terms of levels of metacognitive self-regulation and effort regulation when starting a VET program. However, this difference might not be entirely explained by the learning mode chosen. The findings of this study will provide VET researchers and practitioners with a greater understanding of their students' characteristics when starting the program and the means to develop strategies that ensure their engagement throughout the course
A metodologia da avaliação participativa de planos e ações comunitàries. Três experiências de avaliação participativa em Catalunya
[spa] La Evaluación Participativa (EP) se utiliza con frecuencia para evaluar los planes y acciones comunitarias. Pero, ¿cómo se diseña y se lleva a cabo un proceso de EP?, ¿qué elementos metodológicos diferencian la EP de otras prácticas evaluativas?, ¿qué tipo de herramientas e instrumentos se utilizan? Este artículo intenta responder a estos interrogantes; para ello, se revisa la bibliografía y guías más recientes sobre metodología de la EP. A continuación se describen y se aportan las reflexiones metodológicas sobre el proceso de EP realizado en tres planes comunitarios. Se analizan los aspectos metodológicos más relevantes observados durante la entrada a la comunidad (1), el análisis del contexto (2), la formación del grupo motor (3), la aplicación de técnicas y dinámicas participativas para evaluar las acciones comunitarias y su multiplicación (4), y la evaluación y cierre (5) de los tres procesos de EP. Los resultados permiten identificar aportaciones metodológicas relevantes para la implementación de futuros procesos de Evaluación Participativa en entornos comunitarios, como: los agentes clave para el proceso de entrada en la comunidad, los ejes a tener en cuenta para fomentar la participación, o el papel del equipo de evaluadores.[eng] Participatory evaluation (PE) is frequently used to assess community plans and actions. But how is a PE process designed and carried out? Which methodological elements differentiate PE from other assessment practices? And what kind of tools and instruments are used? This article attempts to answer these questions, though a review of the most recent literature and guidebooks on the EP methodology. Some methodological reflections on the EP process conducted in three community plans are given and described. In this paper we analyze the most relevant methodological aspects observed during entry into the community (1), context analysis (2), the formation of the steering group (3), the application of participatory techniques and dynamics to evaluate community actions, their multiplication (4), and the evaluation and closure of the three processes of EP (5). Results allow identifying relevant methodological contributions to the implementation of future processes of Participatory Evaluation in community settings, as the key stakeholders to the process of entry into the community, some elements to consider in order to encourage participation, and the role of the professional evaluators team
First principles study of the adsorption of C60 on Si(111)
The adsorption of C60 on Si(111) has been studied by means of
first-principles density functional calculations.
A 2x2 adatom surface reconstruction was used to simulate the terraces of the
7x7 reconstruction.
The structure of several possible adsorption configurations was optimized
using the ab initio atomic forces, finding good candidates for two different
adsorption states observed experimentally.
While the C60 molecule remains closely spherical, the silicon substrate
appears quite soft, especially the adatoms, which move substantially to form
extra C-Si bonds, at the expense of breaking Si-Si bonds.
The structural relaxation has a much larger effect on the adsorption
energies, which strongly depend on the adsorption configuration, than on the
charge transfer.Comment: 4 pages with 3 postscript figures, to appear in Surf. Science.
(proceedings of the European Conference on Surface Science ECOSS-19, Sept
2000
The NGC 7771+NGC 7770 minor merger: harassing the little one?
This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. Alonso-Herrero, A., Rosales-Ortega, F.F., Sánchez, S.F., Kennicutt, R.C., Pereira-Santaella, M. and Á.I. Díaz. The NGC 7771+NGC 7770 minor merger: harassing the little one? Monthly Notices of the Royal Astronomical Society 425 (2012): L46-L5
Waardenburg syndrome (WS)
Review on Waardenburg syndrome (WS), with data on clinics, and the genes involved
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