El objetivo de este estudio es analizar el impacto del conocimiento disciplinar de los docentes d... more El objetivo de este estudio es analizar el impacto del conocimiento disciplinar de los docentes de ingles como lengua extranjera en ejercicio en colegios de la region de Tarapaca. El instrumento utilizado fue una entrevista semiestructurada aplicada a nueve profesores de ingles. Los resultados ofrecen una vision sobre el impacto del conocimiento disciplinar en la practica diaria de estos docentes. Este impacto se ve afectado por una serie de factores como el contexto escolar, su formacion de pregrado, su experiencia y creencias. Ademas, los resultados revelaron que algunos profesores entienden el conocimiento disciplinar como el conocimiento de la lengua y como ensenarla, es decir, conocimiento pedagogico del contenido.
DELTA: Documentação de Estudos em Lingüística Teórica e Aplicada, 2019
Conceptual metaphor constitutes both the theoretical framework and a tool for eliciting and analy... more Conceptual metaphor constitutes both the theoretical framework and a tool for eliciting and analyzing data in this qualitative research study. The aim of this study is to analyze the role of conceptual metaphors for unpacking research participants’ conceptualizations about lesson planning in Chilean schools. An eliciting metaphor questionnaire was designed to require respondents to complete the statement “lesson planning is like…because…”. The data were analyzed through content analysis for metaphors, as follows: pre-analysis, labeling, classification, categorizing, peer judgment. The questionnaire was applied to 54 Chilean teachers from different schools. Four metaphor categories were obtained: Map, Foundations, Instructions, Burden.
SIGNIFICANCE Tear film instability has been recognized as one key mechanism on dry eye disease. T... more SIGNIFICANCE Tear film instability has been recognized as one key mechanism on dry eye disease. There is a need for new instruments, methods, or protocols to improve the repeatability and reproducibility of the tear film stability to facilitate its clinical evaluation use as a rapid and reliable primary diagnostic test. PURPOSE The present pilot study aimed to validate a method to automatically measure the tear film breakup time (BUT). METHODS A total of 264 videos of BUT were randomly selected among the clinical history of subjects attending the optometry clinic. Videos were stored in a backup server through a secure file transfer protocol and analyzed by three different examiners: two masked observers (subjective evaluation) and a third investigator using the automatic software application (objective evaluation). Subjective evaluation was conducted only once on an online software designed for this protocol where videos were presented in random masked order. Automatic evaluation based on color and texture analysis was performed by (1) automatic localization of sequences of interest in the video, (2) extraction of the region of interest within each frame, and (3) automatic BUT measurement from evolution curves in the region of interest as time elapsed from the beginning of the sequence of interest until the curve exceeds a threshold. RESULTS Substantial correlation was observed among the examiners (intraclass correlation coefficient, 0.752). There was a statistical difference between observer 1 and 2 evaluations (t test, P < .001), whereas data provided by the software showed no significant differences from those of the observers (t test, P ≥ .26). Similar results to the whole data set analysis were obtained when the sample was reassessed only considering mean BUT values ≤15 seconds. CONCLUSIONS The present pilot study showed acceptable clinical results for the software application designed to objectively measure the BUT.
Studies in health technology and informatics, 2014
Dry eye syndrome is a common disorder of the tear film which affects a remarkable percentage of t... more Dry eye syndrome is a common disorder of the tear film which affects a remarkable percentage of the population. The Break-Up Time (BUT) is a clinical test used for the diagnosis of this disease, which computes the time the first tear film break-up appears. This work describes a fully automatic methodology to compute the BUT measurement and evaluate the break-up dynamics until the final blink. This analysis provides useful additional information for the assessment of tear film stability.
Se presenta el caso de una fractura complicada oblicua de corona y raiz del incisivo central supe... more Se presenta el caso de una fractura complicada oblicua de corona y raiz del incisivo central superior izquierdo, que se extiende hasta la porcion superior del tercio gingival que involucra la pulpa dentaria de un diente con completa formacion apical; se procedio a aplicar una nueva tecnica con el objetivo de conservar el diente, se realizo la exodoncia de los fragmentos involucrados, se realizo tratamiento pulpo radicular in vitro, verificandose por medio de la radiografia y a continuacion se unieron dichos fragmentos con resina fotopolimerizable y aplicamos laserterapia e implante inmediato utilizando para la fijacion una ferula removible acrilica. La reposicion del propio diente fracturado proporciono una estetica aceptable y pasado ano y medio de evolucion se comprobo que se mantiene en optimas condiciones por lo que se ofrece una alternativa mas para el tratamiento de los dientes traumatizados con pronostico desfavorable, contribuyendose de esta forma a lograr una respuesta emoc...
Optometry is the primary health care of the eye and visual system. It involves detecting defects ... more Optometry is the primary health care of the eye and visual system. It involves detecting defects in vision, signs of injury, ocular diseases as well as problems with general health that produce side effects in the eyes. Myopia, presbyopia, glaucoma or diabetic retinopathy are some examples of conditions that optometrists usually diagnose and treat. Moreover, there is another condition that we have all experienced once in a while, especially if we work with computers or have been exposed to smoke or wind. Dry eye syndrome (DES) is a hidden multifactorial disease related with the quality and quantity of tears. It causes discomfort and could lead to severe visual problems. In this chapter, we explain how machine learning techniques can be applied in some DES medical tests in order to produce an objective, repeatable and automatic diagnosis. The results of our experiments show that the proposed methodologies behave like the experts so that they can be applied in the daily practice.
Contextos universitarios transformadores: a nova normalidade académica. Leccións aprendidas e retos de futuro. V Xornadas de Innovación Docente, 2021
Los nuevos paradigmas de la educación digital surgen como nuevas formas de interacción entre doce... more Los nuevos paradigmas de la educación digital surgen como nuevas formas de interacción entre docentes y estudiantes donde la modalidad de enseñanza cambia de presencial a virtual. Sin embargo, las herramientas digitales utilizadas en este modelo educativo pueden crear importantes barreras de comunicación entre los individuos involucrados que inhiben cada vez más la participación activa de los estudiantes. Así, en el contexto de la educación síncrona, es cada vez más importante llevar a cabo actividades pedagógicas mediante el uso de estrategias didácticas innovadoras que fomenten la participación activa de los estudiantes en el proceso de enseñanza-aprendizaje. Con este objetivo, en este trabajo presentamos una estrategia de innovación docente para mejorar la participación y motivación de los estudiantes en la parte práctica de las asignaturas del Máster Internacional Universitario en Visión por Computador (MUVC). Para ello, utilizamos una metodología basada en el seguimiento person...
The recent human coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coron... more The recent human coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been declared as a global pandemic on 11 March 2020 by the World Health Organization. Given the effects of COVID-19 in pulmonary tissues, chest radiography imaging plays an important role for the screening, early detection and monitoring of the suspected individuals. Hence, as the pandemic of COVID-19 progresses, there will be a greater reliance on the use of portable equipment for the acquisition of chest X-Ray images due to its accessibility, widespread availability and benefits regarding to infection control issues, minimizing the risk of cross contamination. This work presents novel fully automatic approaches specifically tailored for the classification of chest X-Ray images acquired by portable equipment into 3 different clinical categories: normal, pathological and COVID-19. For this purpose, two complementary deep learning approaches based on a densely co...
The fundus of the eye is the only part of the human body that allows a direct non-invasive observ... more The fundus of the eye is the only part of the human body that allows a direct non-invasive observation of the circulatory system. Retinal vascular tortuosity presents a valuable potential for diagnostic and treatment purposes of relevant vascular and systemic diseases. This work presents a computational metric for the tortuosity characterization that combines mathematical representations of the vessel segments with anatomical properties of the fundus image such as the vessel caliber, the distance to the optic disc, the distance to the fovea and the distinction between arteries and veins. The evaluation of the prognostic performance shows that the incorporation of the domain-related information allows a reliable characterization of the retinal vascular tortuosity that provides a better representation of the expert perception.
In the year 2020, the world suffered the effects of a global pandemic. COVID-19 is a disease that... more In the year 2020, the world suffered the effects of a global pandemic. COVID-19 is a disease that mainly affects the respiratory system of patients, even causing a disproportionate response of the immune system and further spreading the damage to other vital organs. The main means by which health care services detected this viral disease was through the use of Polymerase Chain Reactions (PCRs). These PCRs allow the detection of known chains of the genetic code of the virus in samples of sputum. In this work, we study PCR signal features that allow to automatize the analysis of hundreds of PCRs. The findings obtained from the study have shown these features to be capable of obtaining successful results in the detection of COVID-19 in PCR samples, with only a small fraction of the information extracted by the clinicians for that purpose.
The analysis of the optic disc and cup in retinal images is important for the early diagnosis of ... more The analysis of the optic disc and cup in retinal images is important for the early diagnosis of glaucoma. In order to improve the joint segmentation of these relevant retinal structures, we propose a novel approach applying the self-supervised multimodal reconstruction of retinal images as pre-training for deep neural networks. The proposed approach is evaluated on different public datasets. The obtained results indicate that the self-supervised multimodal reconstruction pre-training improves the performance of the segmentation. Thus, the proposed approach presents a great potential for also improving the interpretable diagnosis of glaucoma.
El objetivo de este estudio es analizar el impacto del conocimiento disciplinar de los docentes d... more El objetivo de este estudio es analizar el impacto del conocimiento disciplinar de los docentes de ingles como lengua extranjera en ejercicio en colegios de la region de Tarapaca. El instrumento utilizado fue una entrevista semiestructurada aplicada a nueve profesores de ingles. Los resultados ofrecen una vision sobre el impacto del conocimiento disciplinar en la practica diaria de estos docentes. Este impacto se ve afectado por una serie de factores como el contexto escolar, su formacion de pregrado, su experiencia y creencias. Ademas, los resultados revelaron que algunos profesores entienden el conocimiento disciplinar como el conocimiento de la lengua y como ensenarla, es decir, conocimiento pedagogico del contenido.
DELTA: Documentação de Estudos em Lingüística Teórica e Aplicada, 2019
Conceptual metaphor constitutes both the theoretical framework and a tool for eliciting and analy... more Conceptual metaphor constitutes both the theoretical framework and a tool for eliciting and analyzing data in this qualitative research study. The aim of this study is to analyze the role of conceptual metaphors for unpacking research participants’ conceptualizations about lesson planning in Chilean schools. An eliciting metaphor questionnaire was designed to require respondents to complete the statement “lesson planning is like…because…”. The data were analyzed through content analysis for metaphors, as follows: pre-analysis, labeling, classification, categorizing, peer judgment. The questionnaire was applied to 54 Chilean teachers from different schools. Four metaphor categories were obtained: Map, Foundations, Instructions, Burden.
SIGNIFICANCE Tear film instability has been recognized as one key mechanism on dry eye disease. T... more SIGNIFICANCE Tear film instability has been recognized as one key mechanism on dry eye disease. There is a need for new instruments, methods, or protocols to improve the repeatability and reproducibility of the tear film stability to facilitate its clinical evaluation use as a rapid and reliable primary diagnostic test. PURPOSE The present pilot study aimed to validate a method to automatically measure the tear film breakup time (BUT). METHODS A total of 264 videos of BUT were randomly selected among the clinical history of subjects attending the optometry clinic. Videos were stored in a backup server through a secure file transfer protocol and analyzed by three different examiners: two masked observers (subjective evaluation) and a third investigator using the automatic software application (objective evaluation). Subjective evaluation was conducted only once on an online software designed for this protocol where videos were presented in random masked order. Automatic evaluation based on color and texture analysis was performed by (1) automatic localization of sequences of interest in the video, (2) extraction of the region of interest within each frame, and (3) automatic BUT measurement from evolution curves in the region of interest as time elapsed from the beginning of the sequence of interest until the curve exceeds a threshold. RESULTS Substantial correlation was observed among the examiners (intraclass correlation coefficient, 0.752). There was a statistical difference between observer 1 and 2 evaluations (t test, P < .001), whereas data provided by the software showed no significant differences from those of the observers (t test, P ≥ .26). Similar results to the whole data set analysis were obtained when the sample was reassessed only considering mean BUT values ≤15 seconds. CONCLUSIONS The present pilot study showed acceptable clinical results for the software application designed to objectively measure the BUT.
Studies in health technology and informatics, 2014
Dry eye syndrome is a common disorder of the tear film which affects a remarkable percentage of t... more Dry eye syndrome is a common disorder of the tear film which affects a remarkable percentage of the population. The Break-Up Time (BUT) is a clinical test used for the diagnosis of this disease, which computes the time the first tear film break-up appears. This work describes a fully automatic methodology to compute the BUT measurement and evaluate the break-up dynamics until the final blink. This analysis provides useful additional information for the assessment of tear film stability.
Se presenta el caso de una fractura complicada oblicua de corona y raiz del incisivo central supe... more Se presenta el caso de una fractura complicada oblicua de corona y raiz del incisivo central superior izquierdo, que se extiende hasta la porcion superior del tercio gingival que involucra la pulpa dentaria de un diente con completa formacion apical; se procedio a aplicar una nueva tecnica con el objetivo de conservar el diente, se realizo la exodoncia de los fragmentos involucrados, se realizo tratamiento pulpo radicular in vitro, verificandose por medio de la radiografia y a continuacion se unieron dichos fragmentos con resina fotopolimerizable y aplicamos laserterapia e implante inmediato utilizando para la fijacion una ferula removible acrilica. La reposicion del propio diente fracturado proporciono una estetica aceptable y pasado ano y medio de evolucion se comprobo que se mantiene en optimas condiciones por lo que se ofrece una alternativa mas para el tratamiento de los dientes traumatizados con pronostico desfavorable, contribuyendose de esta forma a lograr una respuesta emoc...
Optometry is the primary health care of the eye and visual system. It involves detecting defects ... more Optometry is the primary health care of the eye and visual system. It involves detecting defects in vision, signs of injury, ocular diseases as well as problems with general health that produce side effects in the eyes. Myopia, presbyopia, glaucoma or diabetic retinopathy are some examples of conditions that optometrists usually diagnose and treat. Moreover, there is another condition that we have all experienced once in a while, especially if we work with computers or have been exposed to smoke or wind. Dry eye syndrome (DES) is a hidden multifactorial disease related with the quality and quantity of tears. It causes discomfort and could lead to severe visual problems. In this chapter, we explain how machine learning techniques can be applied in some DES medical tests in order to produce an objective, repeatable and automatic diagnosis. The results of our experiments show that the proposed methodologies behave like the experts so that they can be applied in the daily practice.
Contextos universitarios transformadores: a nova normalidade académica. Leccións aprendidas e retos de futuro. V Xornadas de Innovación Docente, 2021
Los nuevos paradigmas de la educación digital surgen como nuevas formas de interacción entre doce... more Los nuevos paradigmas de la educación digital surgen como nuevas formas de interacción entre docentes y estudiantes donde la modalidad de enseñanza cambia de presencial a virtual. Sin embargo, las herramientas digitales utilizadas en este modelo educativo pueden crear importantes barreras de comunicación entre los individuos involucrados que inhiben cada vez más la participación activa de los estudiantes. Así, en el contexto de la educación síncrona, es cada vez más importante llevar a cabo actividades pedagógicas mediante el uso de estrategias didácticas innovadoras que fomenten la participación activa de los estudiantes en el proceso de enseñanza-aprendizaje. Con este objetivo, en este trabajo presentamos una estrategia de innovación docente para mejorar la participación y motivación de los estudiantes en la parte práctica de las asignaturas del Máster Internacional Universitario en Visión por Computador (MUVC). Para ello, utilizamos una metodología basada en el seguimiento person...
The recent human coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coron... more The recent human coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been declared as a global pandemic on 11 March 2020 by the World Health Organization. Given the effects of COVID-19 in pulmonary tissues, chest radiography imaging plays an important role for the screening, early detection and monitoring of the suspected individuals. Hence, as the pandemic of COVID-19 progresses, there will be a greater reliance on the use of portable equipment for the acquisition of chest X-Ray images due to its accessibility, widespread availability and benefits regarding to infection control issues, minimizing the risk of cross contamination. This work presents novel fully automatic approaches specifically tailored for the classification of chest X-Ray images acquired by portable equipment into 3 different clinical categories: normal, pathological and COVID-19. For this purpose, two complementary deep learning approaches based on a densely co...
The fundus of the eye is the only part of the human body that allows a direct non-invasive observ... more The fundus of the eye is the only part of the human body that allows a direct non-invasive observation of the circulatory system. Retinal vascular tortuosity presents a valuable potential for diagnostic and treatment purposes of relevant vascular and systemic diseases. This work presents a computational metric for the tortuosity characterization that combines mathematical representations of the vessel segments with anatomical properties of the fundus image such as the vessel caliber, the distance to the optic disc, the distance to the fovea and the distinction between arteries and veins. The evaluation of the prognostic performance shows that the incorporation of the domain-related information allows a reliable characterization of the retinal vascular tortuosity that provides a better representation of the expert perception.
In the year 2020, the world suffered the effects of a global pandemic. COVID-19 is a disease that... more In the year 2020, the world suffered the effects of a global pandemic. COVID-19 is a disease that mainly affects the respiratory system of patients, even causing a disproportionate response of the immune system and further spreading the damage to other vital organs. The main means by which health care services detected this viral disease was through the use of Polymerase Chain Reactions (PCRs). These PCRs allow the detection of known chains of the genetic code of the virus in samples of sputum. In this work, we study PCR signal features that allow to automatize the analysis of hundreds of PCRs. The findings obtained from the study have shown these features to be capable of obtaining successful results in the detection of COVID-19 in PCR samples, with only a small fraction of the information extracted by the clinicians for that purpose.
The analysis of the optic disc and cup in retinal images is important for the early diagnosis of ... more The analysis of the optic disc and cup in retinal images is important for the early diagnosis of glaucoma. In order to improve the joint segmentation of these relevant retinal structures, we propose a novel approach applying the self-supervised multimodal reconstruction of retinal images as pre-training for deep neural networks. The proposed approach is evaluated on different public datasets. The obtained results indicate that the self-supervised multimodal reconstruction pre-training improves the performance of the segmentation. Thus, the proposed approach presents a great potential for also improving the interpretable diagnosis of glaucoma.
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Papers by Lucía Ramos