Incidencia de los hábitos de estudio de los estudiantes normalistas en el proceso de enseñanza-aprendizaje de las matemáticas

Este trabajo investigativo es producto de la observación y nace como necesidad de poder aportar al sistema educativo algunos insumos para garantizar la motivación del estudiantado normalista, en cuanto a despertar el interés por el estudio de las matemáticas destacando cómo la falta de hábitos de estudio tiene sus repercusiones en la comprensión de los aprendizajes de la matemática y por ende en el rendimiento académico. Este trabajo pretende indagar sobre la incidencia que tiene los hábitos de estudio en la enseñanza-aprendizaje de matemática, permitirá dar algunos aportes metodológicos sobre cómo los estudiantes de I año deberán buscar las condiciones de aprendizajes que resulten de sus prácticas manifestados por hábitos de estudios como una forma que contribuya a la comprensión de la matemátic

Analysis of the Historical Settlements of the Giralda

The preservation of the cultural heritage is a current challenge for modern societies. Thus, it is important to analyse the structural behaviour of historical buildings in order to detect and prevent future damage. This paper analyses the historical settlements of the Giralda tower of the Cathedral of Seville. Currently, it has a tilt which might have been caused by a differential settlement. With this aim, a detailed characterisation of the foundation and its geotechnical model has been carried out. An accurate 3D Finite Elements Model (FEM) has been used to analyse the settlements, taking into account the different construction phases, the loads, the time of execution and consolidation between phases. Finally, the 3D FEM results have been compared with other previous works and the in-situ measurements of the verticality of the tower. Therefore, the authors have found that the tilt to the south-east direction has been caused by the thicker, soft strata under this corner, which has caused differential settlement in this direction. Moreover, it should be highlighted that a good agreement between the settlements of the model and its real top displacements has been obtained

A deterministic seismic risk macrozonation of Seville

The seismicity of the southwestern Iberian Peninsula is moderate but large events with long return periods occur (≈ 200 years). This exceeds the life of various generations, making the population unacquainted with the seismic hazard. On the one hand, this results in a low demanding seismic code which increases the seismic vulnerability and, therefore, the seismic risk. On the other hand, the local emergency services must be properly prepared to face a destructive seismic event, with emergency plans and mitigation strategies. This assumption enhances the need of assessing the seismic risk of Seville in a civil protection context. For all the aforementioned and for the lack of instrumental data of relevant earthquakes, the assessment of the seismic hazard in this area is challenging. To do this, seismogenic zones of the new seismic hazard map of Spain have been used as sources. The peak ground acceleration (PGA) for each scenario has been calculated by means of ground motion prediction equations (GMPE). To estimate the site efects, in a 1D model environment, a shear wave velocity (Vs) map of the top 5 m has been depicted based on the standard penetration test (SPT). Seville’s building stock has been classifed in agreement with the previous works in Lorca and Barcelona to determine its vulnerability. The main goal of this work was to investigate the infuence of the soil amplifcation on the seismic behaviour of diferent building typologies. Therefore, the fnal target was to plot the damage scenarios expected in Seville under a maximum credible earthquake by means of a deterministic seismic hazard assessment (DSHA). As outputs, the scenario modelled showed that around 27 000 buildings would experience a moderate damage and that 26 000 would sufer pre-collapse or even collapse. Thus, approximately 10% of the population would lose their dwellings. Regarding the human loses, around 22 000 people would sufer serious injuries and approximately 5 000 people would die. Owing to these conclusions, this research evidences the crucial need by civil protection services to implement a local emergency plan as a tool to mitigate the probable consequences that arise from this threat

Determining the best set of seismicity indicators to predict earthquakes. Two case studies: Chile and the Iberian Peninsula

This work explores the use of different seismicity indicators as inputs for artificial neural networks. The combination of multiple indicators that have already been successfully used in different seismic zones by the application of feature selection techniques is proposed. These techniques evaluate every input and propose the best combination of them in terms of information gain. Once these sets have been obtained, artificial neural networks are applied to four Chilean zones (the most seismic country in the world) and to two zones of the Iberian Peninsula (a moderate seismicity area). To make the comparison to other models possible, the prediction problem has been turned into one of classification, thus allowing the application of other machine learning classifiers. Comparisons with original sets of inputs and different classifiers are reported to support the degree of success achieved. Statistical tests have also been applied to confirm that the results are significantly different than those of other classifiers. The main novelty of this work stems from the use of feature selection techniques for improving earthquake prediction methods. So, the infor-mation gain of different seismic indicators has been determined. Low ranked or null contribution seismic indicators have been removed, optimizing the method. The optimized prediction method proposed has a high performance. Finally, four Chilean zones and two zones of the Iberian Peninsula have been charac-terized by means of an information gain analysis obtained from different seismic indicators. The results confirm the methodology proposed as the best features in terms of information gain are the same for both regions.Ministerio de Ciencia y Tecnología BIA2004-01302Ministerio de Ciencia y Tecnología TIN2011-28956-C02-01Junta de Andalucía P11-TIC-752

Hippocampal Dendritic Spines Are Segregated Depending on Their Actin Polymerization

Dendritic spines are mushroom-shaped protrusions of the postsynaptic membrane. Spines receive the majority of glutamatergic synaptic inputs. Their morphology, dynamics, and density have been related to synaptic plasticity and learning. The main determinant of spine shape is filamentous actin. Using FRAP, we have reexamined the actin dynamics of individual spines from pyramidal hippocampal neurons, both in cultures and in hippocampal organotypic slices. Our results indicate that, in cultures, the actin mobile fraction is independently regulated at the individual spine level, and mobile fraction values do not correlate with either age or distance from the soma. The most significant factor regulating actin mobile fraction was the presence of astrocytes in the culture substrate. Spines from neurons growing in the virtual absence of astrocytes have a more stable actin cytoskeleton, while spines from neurons growing in close contact with astrocytes show a more dynamic cytoskeleton. According to their recovery time, spines were distributed into two populations with slower and faster recovery times, while spines from slice cultures were grouped into one population. Finally, employing fast lineal acquisition protocols, we confirmed the existence of loci with high polymerization rates within the spine

Computational Intelligence Techniques for Predicting Earthquakes

Nowadays, much effort is being devoted to develop techniques that forecast natural disasters in order to take precautionary measures. In this paper, the extraction of quantitative association rules and regression techniques are used to discover patterns which model the behavior of seismic temporal data to help in earthquakes prediction. Thus, a simple method based on the k–smallest and k–greatest values is introduced for mining rules that attempt at explaining the conditions under which an earthquake may happen. On the other hand patterns are discovered by using a tree-based piecewise linear model. Results from seismic temporal data provided by the Spanish’s Geographical Institute are presented and discussed, showing a remarkable performance and the significance of the obtained results.Ministerio de Ciencia y tecnología TIN2007-68084-C-02Junta de Andalucía P07-TIC-0261

Optimal ductility enhancement of RC framed buildings considering different non-invasive retrofitting techniques

Existing RC framed buildings lack significant ductility, especially when they have been built with pre-code criteria. Improving their ductile capacity can help to prevent them from the brittle collapse mechanism and to reduce the seismic damage expected. This paper aims to investigate the enhancement of the ductile response behaviour of RC framed buildings considering different non-invasive retrofitting techniques. To do so, a pre-code RC framed school located in the Spanish province of Huelva has been selected as a case study. Five non-invasive retrofitting techniques have been tested: FRP wraps and steel jackets in columns, steel beams and plates under RC beams and single steel braces. They have been selected so that they can be easily implemented in the building. Some of them have been studied in detail in previous works and others have been included for further research in this paper. In order to compare the results obtained, the most typical technique in the seismic retrofitting of RC framed buildings, the addition of X-bracings in bays, has also been tested. Most previous studies on the seismic retrofitting of RC buildings are focused on validating a method based on artificial models. This paper compares the different techniques in terms of the capacity improvement and the damage reduction, performing analyses in detail and adding them in an existing RC building. A sensitivity analysis has been carried out to determine the influence of each technique in the building’s ductile capacity considering the finite element method. Nonlinear static analyses have been performed to obtain the capacity, the displacement ductility factor (μ) and the behaviour factor (q) of each model defined. The damage expected has been determined considering the ductile and fragile failure of the elements according to the Eurocode-8 (EC8) requirements. To analyse the suitability and the efficiency of each solution, a benefit/cost ratio has been obtained taking into account the ductility improvement and the damage reduction with regards to the retrofitting costs. The results have shown that the best benefit has been obtained with the addition of steel braces. However, the optimal solutions have been single braces and steel jackets due to their combination between benefit and cost. It has been observed that the solutions that increase the stiffness of the joints have had a higher improvement due to the key role that joints have in the resistant capacity of RC structurers. Also, it has been obtained that the values of the fundamental periods have been reduced, when adding the retrofitting elements and materials, up to 30% owing to the increase of the stiffness of the system. Finally, it must be highlighted that a detailed analysis of the behaviour of the whole building must be conducted in order to avoid additional rotation effects and shear forces that could worsen the building’s seismic behaviour

Assessment of specific structural and ground-improvement seismic retrofitting techniques for a case study RC building by means of a multi-criteria evaluation

Existing reinforced concrete (RC) structures might not comply with current seismic codes due to their aseismic design and construction date. By seismically retrofitting them, it is possible to improve their seismic performance to resist the expected seismic loads. However, selecting the best solution is challenging since social and economic issues can affect the choice. Multi-criteria decision making (MCDM) provides an opportunity to overcome the challenge but there are some drawbacks in the available MCDM techniques. This paper reports an improved MCDM-based seismic retrofit: Additional criteria have been included and weighted according to their importance (ductility improvement and damage reduction); Finite element modelling of the case study building has been carried out instead of following methods based on different simplifications; iii) Structural performances have been assessed by determining the damage in local elements instead of following global assessment procedures; Effects of soil-structure interaction (SSI) have been taken into account to ultimately compare different structural and ground-improvement techniques. Consistency and sensitivity analyses have proved the stability of the results and the robustness of the method. It is shown that SSI can increase the seismic damage up to 17%, and regarding the seismic safety verification, the building needs to be retrofitted. Adding fibre reinforcement polymers and steel bracings are the best solutions due to the minimum architectural impact and the outstanding structural improvement, respectively. Nevertheless, the solution preferred is the addition of single steel braces in beam- column joints despite its high maintenance costs. The sensitivity analysis indicates that the most sensitive criteria are the functional compatibility and the reduction of the collapse risk

Diseño y cálculo de mallas de alambre postesadas para la estabilización y refuerzo de taludes.

Una solución barata para la protección de taludes es la utilización de mallas de alambre. Este trabajo muestra el diseño de una malla de alambre de alto límite elástico, postesada con anclajes, para la estabilización y refuerzo de taludes. Es una solución económica que permite actuar en terrenos muy altos y empinados. El impacto visual de la malla y los anclajes, una vez colocados, es moderado debido a que la malla es muy flexible, lo que permite su adaptación a las irregularidades del terreno. Además, se puede colorear lo que favorece su camuflaje y ayuda a evitar la erosión del terreno lo que ayuda a la revegetación. También se presenta un modelo de cálculo para la malla. Para ello se han realizado ensayos de laboratorio sobre mallas normalizadas con el objetivo de obtener sus parámetros en condiciones de campo simuladas. Por último, los resultados de los ensayos se han introducido en las ecuaciones teóricas