Diseño y construcción de una línea de extrusión de 60 milímetros para la fabricación de perfiles, tubos y mangueras en materiales termoplásticos

Tesis (Ingeniero Mecánico)-- Corporación Universitaria Autónoma de Occidente, 1991PregradoIngeniero(a) Mecánico(a

Motivation and Perceived Learning of Secondary Education History Students. Analysis of a Programme on Initial Teacher Training

This paper presents the results of research on the initial teacher training in Spain. The aim is to verify whether the development of a training program for teachers based on methodological and epistemological aspects has a positive repercussion on the learning of secondary school pupils. We evaluated to what degree this training was reflected in secondary education pupils (n = 467, Mage = 14.74, SD = 1.97) taught by the participating trainee teachers during their period of teaching practice. A pretest and a postest were employed to obtain data on the methodology and the motivation and perceived learning on the part of the pupils. A confirmatory factor analysis was carried out to verify the validity and internal consistency of the tools and, later, the longitudinal invariance in each of the dimensions analyzed. The results confirm the internal consistency and validity of the tools employed and the improvement in the pupils' evaluation regarding methodology, motivation, and learningThis article has been possible thanks to the research project funded by Ministry of Science, University and Innovation, co-funded by FEDER funding Conceptos Metodológicos y Métodos Activos de Aprendizaje para la Mejora de las Competencias Docentes del Profesorado (PGC2018-094491-B-C33) (MCI/AEI/FEDER, UE), and project Competencias Docentes y Métodos Activos de Aprendizaje. Una Investigación Evaluativa con el Profesorado en Formación de Ciencias Sociales (20638/JLI/18), funded by Seneca Foundation [35500/20638/JLI/18]; Ministry of Science, Innovation and Universities [11550/PGC2018-094491-B-C33] (MCI/AEI/FEDER, UE)S

Patrimonializarte: A Heritage Education Program Based on New Technologies and Local Heritage

This paper presents the design of the Patrimonializarte program, which has been implemented in six classes and three different educational levels in two schools in Galicia (Spain). It involves working with elements of heritage in proximity to the schools’ pupils by employing Information and Communication Technology (ICT) tools. The objectives are (a) to find out if the design is coherent and relevant according to expert judgement and (b) to discover whether the activities related with new technologies are effective according to the evaluation of those involved in the program. This is evaluation research employing mixed methods in which a collective study of cases is carried out. The main results show (1) the evaluation of the design and the tools of the program achieve an optimal degree of agreement according to the panel of experts as far as the variables measured are concerned, and (2) the schoolchildren and teaching staff provide a positive evaluation of the use of ICT tools for working with heritage. E-learning and m-learning make it possible to motivate pupils in the learning and teaching process. Working with ICT tools acquires importance with regard to the possibilities they offer to disseminate the heritage. An integral evaluation of programs is considered relevant in order to understand their multi-dimensionalityThis article has been posible thanks to the research projects “Emotional dimensions and controversial issues in teacher education" (PGC2018-094491-B-C31) & “Methodological concepts and active learning methods for the improvement of teaching competencies” (PGC2018-094491-B-C33), funded by The Ministry of Science, University and Innovation, co-funded by FEDER, and project “Teacher competencies and active learning methods. An evaluative research with trainee teachers of social sciences” (20638/JLI/18), funded by Seneca Foundation. Agency of Science and Technology from Region of MurciaS

A split-based incremental deterministic automata minimization algorithm

The final publication is available at Springer via http://dx.doi.org/10.1007/s00224-014-9588-y. La fecha de publicación corresponde a la versión First OnlineWe here study previous results due to Hopcroft and Almeida et al. to propose an incremental split-based deterministic automata minimization algorithm whose average running-time does not depend on the size of the alphabet. The experimentation carried out shows that our proposal outperforms the algorithms studied whenever the automata have more than a (quite small) number of states and symbols.García Gómez, P.; Vázquez-De-Parga Andrade, M.; Velasco, JA.; López Rodríguez, D. (2014). A split-based incremental deterministic automata minimization algorithm. Theory of Computing Systems. 1-18. doi:10.1007/s00224-014-9588-y118Hopcroft, J.E., Ullman, J.D.: Introduction to Automata Theory, Languages and Computation. Addison-Wesley Publishing Company (1979)Watson, B.W., Daciuk, J.: An efficient incremental DFA minimization algorithm. Nat. Lang. Eng. 9(1), 49–64 (2003)Almeida, M., Moreira, N., Reis, R.: Incremental DFA minimisation. In: Domaratzki, M., Salomaa, K. (eds.) CIAA, of Lecture Notes in Computer Science, vol. 6482, pp 39–48. Springer (2010)Hopcroft, J.E.: An n ⋅ log n $n\cdot \log n$ algorithm for minimizing states in a finite automaton. Technical report, Stanford, University, Stanford (1971)Moore, E.F.: Gedanken experiments on sequential machines. In: Shannon, C.E., Mc-Carthy, J. (eds.) Automata Studies. Princeton Universty Press, Princeton (1956)Berstel, J., Boasson, L., Carton, O., Fagnot, I.: Automata: from Mathematics to Applications, chapter Minimization of automata. European Mathematical Society. (arXiv: 1010.5318v3. ) To appear.David, J.: Average complexity of Moore’s and Hopcroft’s algorithms. Theor. Comput. Sci. 417, 50–65 (2012)Almeida, M., Moreira, N., Reis, R.: Aspects of enumeration and generation with a string automata representation. In: Leung, H., Pighizzini, G. (eds.) DCFS, pp 58–69. New Mexico State University, Las Cruces (2006)Gries, D.: Describing an algorithm by Hopcroft. Acta Informatica 2, 97–109 (1973)Aho, A., Hopcroft, J.E., Ullman, J.D.: The Design and Analysis of Computer Algorithms. Addison-Wesley Publishing Company (1974)Blum, N.: A O ( n log n ) $\mathcal {O}(n\log n)$ implementation of the standard method for minimizing n-state finite automata. Inf. Process. Lett. 57, 65–69 (1996)Knuutila, T.: Re-describing an algorithm by Hopcroft. Theor. Comput. Sci. 250, 333–363 (2001)Veanes, M.: Minimization of symbolic automata. Technical report, Microsoft Research, MSR-TR-2013-48 (2013)Lothaire, M.: Applied Combinatorics on Words chap. 1. Cambridge University Press, Cambridge (2005

Síntesis y caracterización de una perovskita simple del tipo La0.8 Sr0.2CrO3

En estetrabajo se explora la síntesis y caracterización de un óxido cerámico tipo La0.8 Sr0.2 CrO3, a través de intermediarios tipo citrato que propiciaron la obtención de una fase cristalina pura del material a 900 °C

Descripción de la presencia de un caso de teniasis en nuestro medio

Introducción del caso clínico: Varón, de origen español, de 35 años, que refiere prurito anal en la consulta médica de la cárcel donde cumple condena y que lo relaciona con episodios previos diagnosticados de “lombrices”. Estos fueron tratados con Lomper (Mebendazol) de modo empírico. Se le solicitan estudios parasitológicos en heces frescas al servicio de Microbiología del Hospital Virgen de las Nieves de Granada, hallándose la presencia de huevos de Taenia spp. Para ello, la muestra fue concentrada y visualizada en fresco de acuerdo con el procedimiento estándar previamente publicado por nosotros (1). También se observó a 1000X mediante la tinción de ácido alcohol resistencia (Figuras 1 y 2). Se le puso tratamiento para teniasis con Praziquantel. El estudio de control a los tres meses fue negativo. En la anamnesis posterior este negó haber salido del país ni haber tenido contacto con personas de áreas endémicas. Los episodios de prurito anal los sufre desde la adolescencia habiendo sido tratados siempre. Refiere que cuando era adolescente tuvo contacto con un familiar que también tenía lombrices, una tía que tenía cerdos y gallinas y que acudía a matanzas de cerdos en la localidad de Cenes de la Vega (Granada). En su historia clínica constan que los estudios serológicos del VIH, VHA, VHB, VHC y lúes, así como la prueba de Mantoux fueron negativas

La investigación en Didáctica de las Ciencias Sociales en revistas españolas de Ciencias de la Educación. Un análisis bibliométrico (2007-2017)

A bibliometric research is carried out on the scientific production of Didactics of Social Sciences in Spanish education journals. We have analyzed specific and general journals in databases such as JCR, Scopus or with the FECyT quality label. The articles have been quantified and classified, analyzing the topics and their evolution, as well as the institutions that have the highest production. The results show a significant increase in production, especially from 2012. The topics with greater presence and that have increased the most are those about historical education and heritage education. It has become clear that the production is highly concentrated in a few universities, among which Murcia stands out. The conclusion is that Didactics of Social Science has overcome the emerging phase and can now be considered as consolidated, although it has as pending tasks: the increase of production in impact journals and the improvement of network collaboration between universitie

Renewable energy: solar cells of perovskites

Las perovskitas híbridas han tenido un impacto positivo en el campo de la energía renovable, ya que son consideradas como un material prometedor en celdas solares debido a su bajo costo y alta eficiencia. En este caso las celdas solares de película delgada permiten alcanzar eficiencias significativas (21%) en relación a las celdas solares de silicio, este rendimiento se atribuye a sus características como un coeficiente de absorción muy alto, un amplio rango de absorción espectral, una mayor longitud de difusión, entre otras. Sin embargo se han llevado a cabo investigaciones para corregir el problema de degradación de la perovskita y conocer las causas de su baja estabilidad, lo cual impide su aplicación al aire libre. Esta revisión comprende brevemente los conceptos fundamentales de la perovskita, algunas propiedades y técnicas de deposición para la fabricación de la celda solar.The hybrid perovskites have had a positive impact in the field of renewable energy, since they are considered as a promising material in solar cells due to their low cost and high efficiency. In this case the thin-film solar cells allow to achieve significant efficiencies (21%) in relation to silicon solar cells, this performance is attributed to its unique characteristics, such as a very high absorption coefficient, a wide range of spectral absorption, a greater diffusion length, among others. However, investigations have been carried out to correct the problem of degradation of the perovskite and to know the causes of its low stability, which prevents its application in the open air. This review includes the fundamental concepts of perovskite, some properties and deposition techniques for the solar cell.Facultad de Ciencias Agraria

Presence of cadmium and lead in soil and its accumulation in plant tissue in Brachiaria species in the Middle Magdalena colombian

En el Magdalena Medio colombiano confluyen dos actividades económicas: una ganadería intensiva y una consolidada industria petroquímica. Esta última representa un potencial peligro para la Salud Pública, como consecuencia de la emisión de metales tóxicos (plomo y cadmio) que pueden incorporarse a la cadena trófica. Por ello se realizó un inventario de pasturas en esta región en función de la distancia (100, 500, 2500 y 5000 m) al foco emisor contaminante. Así se muestrearon en zonas próximas a la refinería de crudo (Barrancabermeja, Santander), en pozos de extracción (Yondó, Antioquía) y tomando como testigo el Campus académico de la Universidad de la Paz (Barrancabermeja, Santander). Los resultados obtenidos indican una alta frecuencia de representantes de la familia Poaceae y de sus géneros de Brachiaria spp., con importantes diferencias. La información se interpretó en los tres primeros componentes, donde las variables con mayor peso fueron la profundidad del suelo a 5 y 30 cm, tipo de pastura con predominio de las especies introducidas y el transecto en relación a la distancia focal de las fuentes de contaminación. Así, en la zona de la refinería solo se han detectado dos especies de Brachiaria, mientras que en la zona de los pozos de extracción y en la zona testigo se presenta mayor frecuencia de otras especies de Brachiaria. Se concluye que los mayores niveles de bioacumulación de metales en tejidos vegetales presentó el siguiente orden: raíz > tallo > hojas, a su vez la acumulación en suelo mostró ser mayor en la profundidad de 5 cm.In the Middle Magdalena Colombian converge two economic activities: intensive livestock and a consolidated petrochemical industry. The latter represents a potential danger to public health, resulting from the emission of toxic metals (lead and cadmium) that can enter in the food chain. Therefore pasture inventory is performed in this region depending on the distance (100, 500, 2500 and 5000 m) to the emitting source contaminant. So they were sampled near the oil refinery (Barrancabermeja, Santander) in extraction wells (Yondó, Antioquia) and sampling as witness the academic campus of the Universidad de la Paz (Barrancabermeja, Santander) areas. The results indicate a high frequency of representatives of the Poaceae family and its genera Brachiaria, with important differences. The information was interpreted in the first three components, where the variables with more weight were soil depth to 5 and 30 centimeters, type of pasture with predominance of introduced species and transect relative to the focal length of the sources of pollution. Then, in the area of the refinery were detected only two species of Brachiaria, while in the area of the extraction wells and in the control area it is presented a higher frequency of other species of Brachiaria. It_s concluded that higher levels of bioaccumulation of metals in plant tissues presented the following order: root > stem > leaves, turn the accumulation in soil was found to be higher in the depth of 5 cm