Ricardo Castedo

SOFT-CLIFF RETREAT, SELF-ORGANIZED CRITICAL PHENOMENA IN THE LIMIT OF PREDICTABILITY?

The coastal erosion along the worlds coastlines is a natural process that occurs through the actions of marine and subaerial physico-chemical phenomena, waves, tides, and currents. The development of cliff erosion predictive models is limited due to the complex interactions between environmental processes and material properties over a wide range of temporal and spatial scales. As a result of this erosive action, gravity driven mass movements occur and the coastline moves inland. Like other studied earth natural and synthetically modelled phenomena characterized as self-organized critical (SOC), the recession of the cliff has a seemingly random, sporadic behavior, with a wide range of yearly recession rate values probabilistically distributed by a power-law. Usually, SOC systems are defined by a number of scaling features in the size distribution of its parameters and on its spatial and/or temporal pattern. Particularly, some previous studies of derived parameters from slope movements catalogues, have allowed detecting certain SOC features in this phenomenon, which also shares the recession of cliffs. Due to the complexity of the phenomenon and, as for other natural processes, there is no definitive model of recession of coastal cliffs. In this work, various analysis techniques have been applied to identify SOC features in the distribution and pattern to a particular case: the Holderness shoreline. This coast is a great case study to use when examining coastal processes and the structures associated with them. It is one of Worlds fastest eroding coastlines (2 m/yr in average, max observed 22 m/yr). Cliffs, ranging from 2 m up to 35 m in height, and made up of glacial tills, mainly compose this coast. It is this soft boulder clay that is being rapidly eroded and where coastline recession measurements have been recorded by the Cliff Erosion Monitoring Program (East Riding of Yorkshire Council, UK). The original database has been filtered by grouping contiguous sections, with similar geomorphological and dynamic features, to configure a complete and suitable catalogue of yearly recession rates (in m/yr) to analyze. Results show SOC fingerprint characteristics in the limited range scaling of the probability distribution function, in the variographic analysis and in the zero-mean Gaussian distribution of the Fourier coefficients. Therefore it cannot be neglected the possibility that Holderness cliffs behave as a SOC system. According to the discussed results, predictability possibilities of sea-cliff recession phenomena have been concluded.

Flipped classroom-comparative case study in engineering higher education

The use of flipped‐classroom methodology (FC) has increased recently, however, there is a lack of quantitative data on students’ performance. A FC has been applied into a group (80 students) of an obligatory subject of the 2nd course in an Energetic Engineering Bachelor. A second group has been taught with the traditional methodology (72 students) to compare the results. The FC requires students to obtain background knowledge prior to a face‐to face class meeting, and reserves in‐class time for applying knowledge to solve problems. This is the opposite of the traditional lecture‐based classroom, in which students passively attend didactic lectures from the instructor, then study the content and complete assignments after class. The main objectives of this research were to measure the impact of learning (with special attention to really active students), reduce absenteeism, increase exam attendance, and analyze how participating students view their experience with this methodology. The results show that the flipped‐classroom model has a direct impact on student learning (or grades), especially in students with a high degree of involvement (with grades about 1.5 points higher). In addition, the grades standard deviation values were lower (in about one point), ensuring a better general students level. The students are a little reluctant to this new methodology, but thanks to it, they tend to work more (12% of the students work more hours per week), to attend more to class (at least 10% more), and to attend in a higher ratio to exams (around 20%).