Guías basadas en la evidencia

VIII Congreso Iberoamericano de Nutrición. ¿Nutrición basada en la videncia o en la evidencia

Viejos y Nuevos Mundos, una propuesta didáctica para la era de los descubrimientos en 2º de la ESO

No hay resumenDepartamento de Didáctica de las Ciencias Sociales y ExperimentalesMáster en Profesor de Educación Secundaria Obligatoria y Bachillerato, Formación Profesional y Enseñanzas de Idioma

La organización política y la administración del imperio inca

El presente trabajo está destinado a tratar la organización política y la administración del imperio inca, Tahuantinsuyo en quechua. Los incas destacaron en ambos aspectos para llegar a su máximo desarrollo estatal que, junto a su capacidad bélica, les permitió reunir bajo su gobierno a las diferentes comunidades que habitaban el espacio de los Andes centrales. Si bien el Tahuantinsuyo no constituyó el primer proceso de centralización y unificación política de la región, si supuso llevar hasta las últimas consecuencias ambas premisas, creando un sólido y compacto aparato estatal, caracterizado por su militarismo, así como las relaciones de reciprocidad y redistribución. Su desarrollo dio comienzo en el año 1438 con el Sapa Inca Pachacútec, pero de forma abrupta terminaría un siglo más tarde por los efectos de la guerra civil desatada entre Atahualpa y Huáscar, y la sorpresiva aparición de los españolesDepartamento de Historia Moderna, Contemporánea y de América, Periodismo y Comunicación Audiovisual y PublicidadGrado en Histori

Estudio sobre la reducción de antraquinona con sulfuro sódico : aplicación a la industria papelera

Se estudia la viabilidad de un procedimiento de solubilizacion de antraquinona basado en su reducción a la sal disodica del 9,10-dihidroxiantraceno, mediante el empleo de las lejías blancas del proceso kraft para la obtención de pastas en la fabricación de papel. El estudio se ha estructurado de acuerdo con los siguientes puntos: - análisis de la termodinámica de la reducción de antraquinona con disoluciones alcalinas de sulfuro sódico. Determinación de las etapas y potenciales redox de las especies quinonicas implicadas en el proceso. - comprobación de la extensión de la reducción de la antraquinona en condiciones de operacion propias de la industria papelera. Así mismo, se cuantifica el peso de cada una de las variables sobre el proceso. - por último, se aborda el estudio de la cinética de reducción de antraquinona. Los resultados se ajustan al modelo de núcleo decreciente para partículas de geometría cilíndrica, sin formación de cenizas, con la reacción química superficial como etapa controlante

Raw-crushed wind-turbine blade: Waste characterization and suitability for use in concrete production

Many of the first wind-turbine installations are reaching the end of their useful life, so their blades have to be replaced. Inexpensive, sustainable, and straightforward recycling solutions are therefore needed. The conversion of turbine blades into raw materials for concrete solutions is proposed in this paper, through a novel recycling process entailing non-selective cutting, crushing, and sieving of the blade walls, without component separation. The material, Raw-Crushed Wind-Turbine Blade (RCWTB), consists of fiberglass-composite fibers, polyurethane, and balsa-wood particles. It serves as concrete fibers and aggregates, according to its physical and microscopic characterizations. A customized concrete mix design and a five-stage mixing procedure with up to 6% RCWTB achieved suitable workability levels. The compressive strength of the RCWTB concrete was 40 MPa, and it had a higher load-bearing capacity and a lower carbon footprint than ordinary concrete. The results encourage research on the overall performance of RCWTB concretes.This research work was supported by the Spanish Ministry of Universities, MICINN, AEI, EU, ERDF and NextGenerationEU/PRTR [grant numbers PID2020-113837RB-I00; 10.13039/501100011033; TED2021-129715B-I00]; the Junta de Castilla y León (Regional Government) and ERDF [grant number UIC-231]; and, finally, the University of Burgos [grant number SUCONS, Y135.GI]

Effect of fine recycled concrete aggregate on the mechanical behavior of self-compacting concrete

The high flowability of Self-Compacting Concrete (SCC) is achieved by adding large amounts of fine aggregate. Therefore, the addition of fine Recycled Concrete Aggregate (RCA) in this type of concrete can very noticeably change its behavior. SCCs with different percentages of fine RCA (0%, 25%, 50%, 75%, and 100%) and 100% coarse RCA were manufactured in this study, to evaluate their performance, and to analyze the effect of fine RCA in an SCC when a high amount of coarse RCA is also added. Both the fresh properties (flowability, density, and air content) and their mechanical behavior (strengths, non-destructive tests, stress–strain curves, and Poisson coefficient) at different curing ages were studied. These mechanical properties were compared with the values calculated using the formulas from two of the most common structural design standards. High values of strength and modulus of elasticity were obtained up to a fine RCA content of 50%. Additionally, any increase in fine RCA increased flowability and elastic and plastic deformability of the SCC. The theoretical values overestimated the experimental ones by around 25%. From the mechanical point of view, SCC with up to 50% fine RCA could be used for structural applications, although service requirements regarding deformability recommend that its content should be limited to 25%.The authors wish to express their gratitude to: the Spanish Ministry MCI, AEI, EU and ERDF [grant number FPU17/03374]; the Junta de Castilla y León (Regional Government) and ERDF [grant numbers UIC-231, BU119P17]; Youth Employment Initiative (JCyL) and ESF [grant number UBU05B_1274]; and finally, the University of Burgos [grant numbers SUCONS, Y135.GI]

Multi-parametric flowability classification of self-compacting concrete containing sustainable raw materials: An approach to real applications

Adding sustainable raw materials to Self-Compacting Concrete (SCC) modifies its flowability behavior. Furthermore, the use of these raw materials may at the same time even improve one fresh property while worsening another. An accurate flowability description of SCC containing sustainable raw materials therefore requires a multi-parametric classification that simultaneously covers all fresh properties (slump flow, viscosity, and blocking ratio) for an accurate description of its potential applications. Existing classifications consider each fresh property independently. In this paper, a multi-parametric flowability classification of SCC containing sustainable raw materials is proposed. The effects of multiple sustainable raw materials on SCC flowability are compiled in a dataset serving as a knowledge base with information on 663 SCC mixes containing sustainable aggregates and binders. The statistical analysis of the dataset led to the definition of three types of flowability zones. Firstly, the overall-flowability zones, in which SCC flowability is described in absolute terms: the better the in-fresh properties, the better the overall-flowability zone. Secondly, the flowability-balance zones reflect the balance between free flow (slump flow and slump-flow viscosity) and flow around obstacles (V-funnel emptying time and L-box blocking ratio). Finally, SCC is classified within flowability-predominance zones, which define the main characteristic of SCC flowability, rate of flow (viscosity) or uniformity of flow (spreading). The variability of the effect of each sustainable raw material on the flowability of SCC makes this classification useful, in so far as it offers a complete picture of the fresh behavior of SCC in which all fresh properties are simultaneously considered. Furthermore, based on the description in the proposed classification of overall flowability and the balance between free flow and flow around obstacles, the application fields are defined for which the use of each SCC mix with sustainable raw materials is recommended.This research work was supported by the Spanish Ministry of Universities, MICINN, AEI, EU, ERDF and NextGenerationEU/PRTR [grant numbers PID2020-113837RB-I00; 10.13039/501100011033; TED2021-129715B–I00; FPU17/03374]; the Junta de Castilla y León (Regional Government) and ERDF [grant number UIC-231]; and, finally, the University of Burgos [grant number SUCONS, Y135. GI]

Student Perceptions of Formative Assessment and Cooperative Work on a Technical Engineering Course

Formative Assessment and Cooperative Work (FACW) is a teaching methodology that promotes student learning based on peer support, both in solving problems and identifying the mistakes made through feedback. The perceptions of 49 mechanical engineering students at the University of Burgos are analyzed in this article with regard to their first practical experience of FACW methodology in a technical subject, characterized by a highly complex content and a strong link between theoretical and practical concepts. The responses of the students to two blocks of open questions were evaluated in a qualitative, mixed, and statistical analysis. Various aspects that the students raised in relation to FACW could therefore be studied, such as their points of view towards: (1) The usefulness of FACW teaching modality; and (2) their preferences regarding the optimum teaching modality. The results showed that, although the students expressed favorable opinions towards FACW, they did not consider, in general, that teamwork was necessary for optimal learning, revealing a clear dependence on formal classroom presentations for the explanation of theoretical concepts. Students considered that theoretical concepts could not be autonomously acquired. Therefore, the application of the FACW teaching methodology to these courses could be especially beneficial to favor autonomous learning and to develop teamwork skills, training engineers with the right knowledge and skills today for tomorrow’s world.This research was funded by the following entities and grants: Spanish Ministry MCI, AEI, EU, and ERDF, grants PID2019-106635RB-I00, 10.13039/501100011033, and FPU17/03374; the Junta de Castilla y León and ERDF, grant BU119P17 awarded to research group UIC-231; Youth Employment Initiative (JCyL) and ESF, grant UBU05B_1274; and the University of Burgos through grant Y135 GI awarded to the SUCONS group

El dilema limitación/suspensión de derechos y otras «distorsiones» al hilo de la pandemia

El artículo examina el dilema limitación /suspensión de derechos a la luz de la sentencia del Tribunal Constitucional 148/2021, analiza la cuestión de los estados excepcionales, así como la del control judicial sobre las medidas restrictivas de derechos adoptadas por las Comunidades Autónomas. Y preconiza aprobación de una nueva Ley Orgánica de Emergencias Sanitarias que rescate tales situaciones del ámbito del Derecho de excepción