Proyectos

La alfabetización en retroalimentación es un campo cada vez más explorado por la importancia que posee. Sin embargo, aunque hay iniciativas que promueven la escritura académica y su retroalimentación en la formación universitaria, se presta menos atención a cómo los estudiantes incorporan los comentarios de retroalimentación en futuras tareas. El propósito de este proyecto es examinar cómo estudiantes de Pedagogía en Educación Básica de una universidad chilena asimilan la retroalimentación al resolver un Aprendizaje Basado en Problemas (ABP). Se explora la escritura de un Informe de resolución de problemas (IRP) como forma de comunicar los aprendizajes del ABP, pues implica desarrollar habilidades como la indagación, la formulación de preguntas de investigación, el análisis crítico de fuentes y el trabajo colaborativo. A partir de una intervención didáctica en la elaboración de IRP se analizan comentarios de los profesores para determinar si se centran solo en la retroalimentación (feedback) o también ofrecen orientación futura (feedforward). Asimismo, se abordan las percepciones de los estudiantes con respecto a la formación recibida.

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One goal is to enhance the methods being currently developed by Espı́ndola (Physics), Krause (Physiology), and Xavier (Biomedical Engineering) for reconstructing capillary networks with ultrasound. The super-resolution is needed for early detection diseases such as cognitive decline, cancer, or liver fibrosis. They perfuse lipid-encapsulated microbubbles as contrast agents and then localize the bubbles in the ultrasound images with the singular value filter. However, that method leaves a non-negligible percentage of bubbles undetected. Here we propose to complement the singular value filter for the detection and tracking of microbubbles with the sophisticated and mathematically sound Mumford-Shah method for image contour detection, which stems from the conceptually-insightful and numerically-robust perspective of the minimization of energies. In the reconstruction of the capillary network from ultrasound, it is impossible to directly distinguish the microbubbles, or even the blood vessels, in each frame separately, due to the attentuation and degradation in this imaging technique. It is essential to take into account the dynamic nature of the problem, distinguishing the slowly-varying signals emitted by the tissue from those emitted by the microbubbles, which flow rapidly, behave nonlinearly, and have a much shorter coherence length. We therefore propose to regard the collection of two-dimensional frames as a single three-dimensional image, where a moving bubble becomes a tubular neighbourhood of a filament, which the Mumford-Shah model is expected to recover. From these filaments, bubbles can be detected and tracked, and the vertical inclinations of theses filaments will yield the microbubbles velocities. From the velocity profiles it is possible to estimate the shear wall stresses (their ‘tangential elastic rigidities’) of the blood vessels, and anomalies in these stresses are commonly good indicators of the presence of specific diseases. A fortunate encounter between mathematics and mechanics led to the observation that the problem of finding the path that the propagation of a crack will follow inside a structure upon loading could be solved with the mathematical theory (the analysis of free-discontinuity problems) developed for the apparently unrelated image segmentation Mumford-Shah model. The variational fracture theory initiated by Francfort and Marigo is by now (20 years after) very well established. The second goal of this proposal is to further develop the ongoing collaboration between Song (Pharmaceutics), Siegel (Pharmaceutics), Sánchez (Numerical analysis), Calderer (Applied mathematics), and the PI on the study of the debonding of polymer gels from rigid substrates (relevant in the design of the synthetic polymers coating the metallic parts of pacemakers and other medical prostheses) from this variational fracture theory perspective. The third main goal is to apply the mathematical analysis of free-discontinuity problems to the modelling of the evolution of the cavity in the block caving technique in underground rock mining. This has been pursued by Ortega, Lecaros, and coworkers from the side of applied mathematics in academia, in collaboration with Gaete from the Geomechanics Research Department at El Teniente, research group to which Gutiérrez and the PI have joined in the last months. We propose to study the seismic activity induced by the fracture of the rock mass due to gravity, following the works in the last decade within the variational fracture theory that incorporate the inertia effects. The final aim is to optimize the injection of water jets for the aminoration of the seismic events near the operation sites. The three research lines are applications of the phase-field regularization by Ambrosio and Tortorelli of the Mumford-Shah free-discontinuity model, a different variant being required in each of the three contexts. The first stage of the implementation is of mathematical modelling and high-level numerical simulation abilities, in which the intuition and first-hand knowledge from the members of the research team that are experts in vascular function, ultrasound imaging, polymer chemistry, and mining geomechanics is translated into particular mathematical concepts and concrete computational methods. This is followed by a stage of calibration and validation, where the full interplay with experiments is required. The product of a robust and validated computational method will constitute then an advancement in the capabilities, available resources, and understanding in each of the applied disciplines.

El presente proyecto propone estudiar cómo los dispositivos de práctica reflexiva, presentes en la formación inicial docente (FID), contribuyen a la elaboración de juicios profesionales de los profesores en formación (PF). Para ello, se formula una propuesta que moviliza la noción de “dispositivo” para problematizar de modo articulado componentes que han sido estudiados de manera disociada por la investigación especializada (programas de formación y herramientas que incitan la práctica reflexiva; acompañamiento y co-contrucción de la práctica reflexiva; los modelos profesionales y la identidad profesional derivados de la práctica reflexiva), así como la noción de juicios profesionales que entiende la práctica reflexiva como un proceso de toma de decisiones o de posicionamiento profesional contextualizado (realizado desde un lugar, en un momento), multinivel (en términos de dónde se sitúa el objeto de la práctica reflexiva y las estrategias, saberes profesionales y finalidades asociadas), multiactor (el PF que desarrolla su práctica reflexiva, el formador que la acompaña o el par que la co-construye) y que implica en su elaboración y ejercicio importantes elementos identitarios.

One goal is to enhance the methods being currently developed by Espı́ndola (Physics), Krause (Physiology), and Xavier (Biomedical Engineering) for reconstructing capillary networks with ultrasound. The super-resolution is needed for early detection diseases such as cognitive decline, cancer, or liver fibrosis. They perfuse lipid-encapsulated microbubbles as contrast agents and then localize the bubbles in the ultrasound images with the singular value filter. However, that method leaves a non-negligible percentage of bubbles undetected. Here we propose to complement the singular value filter for the detection and tracking of microbubbles with the sophisticated and mathematically sound Mumford-Shah method for image contour detection, which stems from the conceptually-insightful and numerically-robust perspective of the minimization of energies. In the reconstruction of the capillary network from ultrasound, it is impossible to directly distinguish the microbubbles, or even the blood vessels, in each frame separately, due to the attentuation and degradation in this imaging technique. It is essential to take into account the dynamic nature of the problem, distinguishing the slowly-varying signals emitted by the tissue from those emitted by the microbubbles, which flow rapidly, behave nonlinearly, and have a much shorter coherence length. We therefore propose to regard the collection of two-dimensional frames as a single three-dimensional image, where a moving bubble becomes a tubular neighbourhood of a filament, which the Mumford-Shah model is expected to recover. From these filaments, bubbles can be detected and tracked, and the vertical inclinations of theses filaments will yield the microbubbles velocities. From the velocity profiles it is possible to estimate the shear wall stresses (their ‘tangential elastic rigidities’) of the blood vessels, and anomalies in these stresses are commonly good indicators of the presence of specific diseases. A fortunate encounter between mathematics and mechanics led to the observation that the problem of finding the path that the propagation of a crack will follow inside a structure upon loading could be solved with the mathematical theory (the analysis of free-discontinuity problems) developed for the apparently unrelated image segmentation Mumford-Shah model. The variational fracture theory initiated by Francfort and Marigo is by now (20 years after) very well established. The second goal of this proposal is to further develop the ongoing collaboration between Song (Pharmaceutics), Siegel (Pharmaceutics), Sánchez (Numerical analysis), Calderer (Applied mathematics), and the PI on the study of the debonding of polymer gels from rigid substrates (relevant in the design of the synthetic polymers coating the metallic parts of pacemakers and other medical prostheses) from this variational fracture theory perspective. The third main goal is to apply the mathematical analysis of free-discontinuity problems to the modelling of the evolution of the cavity in the block caving technique in underground rock mining. This has been pursued by Ortega, Lecaros, and coworkers from the side of applied mathematics in academia, in collaboration with Gaete from the Geomechanics Research Department at El Teniente, research group to which Gutiérrez and the PI have joined in the last months. We propose to study the seismic activity induced by the fracture of the rock mass due to gravity, following the works in the last decade within the variational fracture theory that incorporate the inertia effects. The final aim is to optimize the injection of water jets for the aminoration of the seismic events near the operation sites. The three research lines are applications of the phase-field regularization by Ambrosio and Tortorelli of the Mumford-Shah free-discontinuity model, a different variant being required in each of the three contexts. The first stage of the implementation is of mathematical modelling and high-level numerical simulation abilities, in which the intuition and first-hand knowledge from the members of the research team that are experts in vascular function, ultrasound imaging, polymer chemistry, and mining geomechanics is translated into particular mathematical concepts and concrete computational methods. This is followed by a stage of calibration and validation, where the full interplay with experiments is required. The product of a robust and validated computational method will constitute then an advancement in the capabilities, available resources, and understanding in each of the applied disciplines.

El presente proyecto propone estudiar cómo los dispositivos de práctica reflexiva, presentes en la formación inicial docente (FID), contribuyen a la elaboración de juicios profesionales de los profesores en formación (PF). Para ello, se formula una propuesta que moviliza la noción de “dispositivo” para problematizar de modo articulado componentes que han sido estudiados de manera disociada por la investigación especializada (programas de formación y herramientas que incitan la práctica reflexiva; acompañamiento y co-contrucción de la práctica reflexiva; los modelos profesionales y la identidad profesional derivados de la práctica reflexiva), así como la noción de juicios profesionales que entiende la práctica reflexiva como un proceso de toma de decisiones o de posicionamiento profesional contextualizado (realizado desde un lugar, en un momento), multinivel (en términos de dónde se sitúa el objeto de la práctica reflexiva y las estrategias, saberes profesionales y finalidades asociadas), multiactor (el PF que desarrolla su práctica reflexiva, el formador que la acompaña o el par que la co-construye) y que implica en su elaboración y ejercicio importantes elementos identitarios.

Materia investigada: Biomedicina, enfermedades cardiovasculares, regulación transcripcional.

Materia investigada: Regulación transcripcional, microbiología, metilaciones, cobre.

Materia investigada: Biomedicina, enfermedades cardiovasculares, regulación transcripcional.

Materia investigada: Regulación transcripcional, microbiología, metilaciones, cobre.