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Constraining the Flatness of Planetary Systems
No full textTesis (Doctor of Philosophy in Astrophysics)--Pontificia Universidad Católica de Chile, 2025Over the past 30 years, nearly 6,000 exoplanets have been discovered, revealing a remarkable diversity of planetary systems. Essential information about the formation of these systems can be found in their current architectures, as they serve as a signature of their dynamical evolution. Much of what we currently know about architectures comes from the study of stellar obliquities--the angle between the stellar spin axis and the planet's orbital normal--in hot Jupiter systems. However, hot Jupiters are intrinsically rare, with an occurrence rate of 1%, highlighting the need to explore architectures in a broader range of planetary systems. In this thesis, I study the architectures of planetary systems beyond hot Jupiters, focusing on warm Jupiter and Neptune systems through stellar obliquity measurements. Using VLT/ESPRESSO observations of the Rossiter-McLaughlin effect, I have found that these different exoplanet populations have different obliquity distributions: i) hot Jupiters show a two-component distribution, with one population of aligned systems and another approximately isotropic population of misaligned systems; ii) independent of their eccentricities, warm Jupiters are typically well aligned; iii) Neptunes appear to have a bimodal distribution of well-aligned and polar systems. These contrasting obliquity distributions suggest distinct formation pathways for each population. Finally, I also discuss prospects and make predictions for measuring mutual inclinations--the angle between different orbital planes of different planets in the same system--using future Gaia astrometric data. I show that these measurements have the potential to provide deeper insights into the formation and evolution of a larger and more diverse sample of planetary systems.ANI
Evaluating the Environmental Impacts of Nanocellulose Production using Conventional and Novel Approach at Laboratory Scale
No full textGreen chemistry promotes the design and application of chemical products and processes that reduce or preferably eliminate the use and generation of hazardous substances. The objective of this research was to evaluate the environmental performance of two methods of producing nanocellulose at the laboratory scale: (i) a conventional sulphuric acid hydrolysis that has been upscaled for industrial use (TRL 8-9); and (ii) the novel approach using the ternary eutectic mixture ChCl: pTSA: PA molar ratio (1:1:1.35) that is currently at TRL 2. The purpose of developing the new approach was to find a better alternative to the conventional process from an environmental perspective. To validate this, life cycle assessment was used to compare conventional vs novel methods with the functional unit of 1 g nanocellulose produced. The system boundary was from cradle to laboratory gate. The results were interpreted to select the best method for laboratory use and to identify design issues to address during upscaling of the novel method. For both methods, conventional and novel, the impact categories selected were climate change (kgCO2 eq), Acidification (kg SO2 eq), Ecotox Air (CTUe) and Eutrophication (kg N eq). To produce 1 g of nanocellulose with sulphuric acid caused a climate impact of between 68 kg CO2 eq (90% yield) to 105 kg CO2 eq (57% yield). Produced using DES the climate impact ranged from 85 kg CO2 eq.(90% yield) to 132 kg CO2 (57% yield). The results indicated that the novel method created greater impacts over the whole life cycle. Unless significant changes are made during upscaling, the novel method will not make a positive contribution to sustainable, circular bioeconomy. The method does have potential to be improved to reduce impact, including using decarbonised energy, a renewable, bio-based feedstock for the cellulose and choline chloride to improve the overall efficiency of using deep eutectic solvent (DES) at pilot scale. The low TRL life cycle assessment offered insights not possible if only the laboratory stage of the analysis had been considered
Perception of Attachment Security, Neurodynamics of Emotion Recognition, and Social Skills in Late Childhood and Early Adolescence: A Multilinear Modeling Study
No full textSociety for Psychophysiological Research.This study explores the relationship between perception of attachment security (PAS), neurobehavioral dynamics during emotion recognition, and social skills (SSk) in late childhood and early adolescence using a multilinear modeling approach. Participants engaged in a facial expression of emotion recognition task while electroencephalography (EEG) signals were recorded. Our multilinear modeling approach aims to capture the interaction between what is predefined as “known” and “unknown” effects in a more interpretable manner. Based on prior research and theoretical perspectives, it was hypothesized that higher PAS levels would be associated with improved performance in emotion recognition tasks, including enhanced accuracy, faster reaction times, and distinct neurobehavioral dynamics. Additionally, superior task performance was predicted to be linked to enhanced social skills. Results show early midline occipital increment in neurobehavioral dynamics at approximately 70 and 170 ms, indicating that attachment security shapes the organization of the nervous system and facilitates early neurobehavioral processes. This finding suggests that individuals with higher attachment security levels possess a heightened ability to perceive and understand emotions, ultimately contributing to enhanced social competence. Furthermore, social competence was found to influence early dynamics over right hemisphere sensors, underscoring the significance of positive social skills and attachment security in integrating facial expressions of emotions. During later processing stages, dynamics associated with antisocial behavior exhibited an increment around 200 ms after stimulus onset. This finding suggests that cognitive resources may be allocated toward disengaging from or sustaining emotional processing, potentially impeding the consideration of interpersonal interactions and contextual factors crucial for social skill development. Understanding the relationship between neurobehavioral dynamics, antisocial behavior, and social competence highlights the importance of considering a broader range of factors to fully comprehend social competence.ANID/FONDECYT; Folios de beca: 1090610; 11180620CONICYT /FONDECYT; Folio de beca: 119061
Student Perceptions and Beliefs on the Use of Digital Technologies from an Innovation Experience in an Introductory Linear Algebra Course
No full text© 2025 by the authors.This study addresses a critical gap in mathematics education by examining student perceptions of digital technology integration in an introductory linear algebra course in Chile. Although technology use in higher education is expanding, little is known about how different student groups, such as undergraduate mathematics students and pre-service teachers, engage with these tools in advanced mathematical contexts like linear algebra—a subject essential across Science, Technology, Engineering, Mathematics (STEM) fields but challenging to teach due to its abstract nature. Data from 59 participants were gathered via a questionnaire assessing engagement, perceived benefits, and motivation toward digital tools like SageMath and Canvas Learning Management System (LMS). Reliability analysis and statistical methods, including t-tests, ANOVA, and correlation, were employed to explore group differences and relationships between perceptions and technology use. Findings show that pre-service teachers reported significantly higher motivation (p < 0.001) and perceived greater benefits (p < 0.03) compared to undergraduates. A strong positive correlation (r = 0.71, p < 0.001) was found between perceptions of technology’s professional relevance and engagement with digital tools. This study contributes to understanding how different student cohorts perceive and use technology in linear algebra education, underscoring the need for tailored strategies in technology-enhanced learning environments.FondefFondefFondo Basa
Naturaleza de la disciplina, fuentes y contencioso administrativo en los Principios elementales de Derecho administrativo de Santiago Prado, de 1859: Anotaciones y reedición de extractos
No full text© 2025 Cambridge University Press. All rights reserved.Background: The macro-social and environmental conditions in which people live, such as the level of a country’s development or inequality, are associated with brain-related disorders. However, the relationship between these systemic environmental factors and the brain remains unclear. We here aimed to determine the association between the level of development and inequality of a country and the brain structure of healthy adults. Methods: We conducted a cross-sectional study pooling brain imaging (T1-based) data from 145 magnetic resonance imaging (MRI) studies in 7,962 healthy adults (4,110 women) in 29 different countries. We used a meta-regression approach to relate the brain structure with the country’s level of development and inequality. Results: Higher human development was consistently associated with larger hippocampi and more expanded global cortical surface area, particularly in frontal areas. Increased inequality was most consistently associated with smaller hippocampal volume and thinner cortical thickness across the brain. Conclusions: Our results suggest that the macro-economic conditions of a country are reflected in its inhabitants’ brains and may explain the different incidence of brain disorders across the world. The observed variability of brain structure in health across countries should be considered when developing tools in the field of personalized or precision medicine that are intended to be used across the world.FONDECYT; Folios: 1250261, 125025
National Exposure Model for Industrial Structures in Chile
No full textThe 2010 Maule mega-earthquake produced estimated damage in Chile of 30 billion dollars, of which until today, the percentage corresponding to the cost associated with damage to industrial structures is unknown. This has generated concern regarding what will happen in the next major seismic event. Therefore, the need arises to incorporate seismic risk information in government disaster risk reduction measures.In recent years, progress has been made in exposure models for residential buildings, but only a small number of investigations include industrial buildings, mainly due to the lack of information available in the databases and the difficulty in obtaining additional information from the private sector. This generates the need to computationally collect and process data obtained from existing databases and information obtained remotely.The result of this research consists of the definition of a methodology and subsequent obtaining of an exposure model at the national level that includes the quantification, geographical location and the definition of characteristic typologies of industrial buildings in Chile, through its own flexible taxonomy that provides the necessary information for the subsequent structural modeling of each constructive typology. Given the limited information available and restricted access to industrial sites, the research adopts a hybrid methodology that combines statistical analysis of public cadastral data with remote visual surveys. In addition to obtaining an exposure model, the available information sources are discussed and compared, indicating the associated uncertainties and the assumptions considered
Esquejes in co-labour: pluriversal design and visual artefacts of Indigenous landscapes in Caspana, Chile
No full textThis article explores co-labour as a research method within the framework of pluriversal ontological design, introducing esquejes–a concept alluding to plant cuttings in Spanish. Framed by the concepts of care and situated knowledge proposed by de la Bellacasa and Haraway, and the idea of pluriversal ontological design by Escobar, this article investigates knowledge exchange around Indigenous landscapes mediated by esquejes. The article highlights the ability of esquejes to function as boundary objects that facilitate dialogue and knowledge exchange, challenging conventional notions of authorship and participatory research. It examines three cases where esquejes have taken on a life of their own, serving as tools for display, narrative guides, and sources of empowerment within communities. The results of these cases are presented as photo essays, with each collage documenting the creation and significance of these visual objects. Furthermore, from an ethical perspective, the article posits the importance of relinquishing authorship in co-labouring. The article concludes by emphasising the need to focus on the methods employed and relinquishing control over research outcomes. This study not only contributes to the discourse on intercultural collaboration but also positions esquejes as a relational and ontological methodology, mediating knowledge exchange between Indigenous communities and non-Indigenous researchers
Experiencia de Formación en Danza de Niñas del Sur de Chile: Conocer, Hacer, Vivir juntas y Ser a través de la Danza
No full textEsta investigación se llevó a cabo en 2021 durante seis meses en un curso de danza en la Región de los Lagos, al sur de Chile, entrevistando a siete niñas en formación y observando sus clases dos veces por semana. El objetivo fue documentar la experiencia de estudiar danza durante la niñez dentro de este contexto particular, indagando desde su discurso en su proceso formativo, su autopercepción en lo artístico, académico y socioemocional, y en sus sueños personales y colectivos. Los hallazgos muestran que la formación en danza implica mucho más que aprender movimientos: fomenta una conciencia corporal, emocional y social. El aprendizaje por imitación y conexión con el entorno regional (viento, agua, fauna, volcanes) es fundamental. La danza se convierte en hábito y hábitat. Lo primero porque significa una rutina y estructura de vida para las niñas, la cual gira en torno a la danza. Lo segundo porque bailar implica un conocimiento compartido con compañeras, profesores y familiares, aprendiendo también en espacios como pasillos y camarines, donde la danza crea un entorno de aprendizaje colectivo. Finalmente, la danza se proyecta como una pasión y parte esencial de sus identidades, integrándose profundamente a sus vidas y aspiraciones
Challenges and Potential of Remote Sensing for Assessing Salmonella Risk in Water Sources: Evidence from Chile
No full textWaterborne illnesses, including those caused by Salmonella, are an increasing public health challenge, particularly in developing countries. Potential sources of salmonellosis include fruits and vegetables irrigated/treated with surface water, leading to human infections. Salmonella causes millions of gastroenteritis cases annually, but early detection through routine water quality surveillance is time-consuming, requires specialized equipment, and faces limitations, such as coverage gaps, delayed data, and poor accessibility. Climate change-driven extreme events such as floods and droughts further exacerbate variability in water quality. In this context, remote sensing offers an efficient and cost-effective alternative for environmental monitoring. This study evaluated the potential of Sentinel-2 satellite imagery to predict Salmonella occurrence in the Maipo and Mapocho river basins (Chile) by integrating spectral, microbiological, climatic, and land use variables. A total of 1851 water samples collected between 2019 and 2023, including 704 positive samples for Salmonella, were used to develop a predictive model. Predicting Salmonella in surface waters using remote sensing is challenging for several reasons. Satellite sensors capture environmental proxies (e.g., vegetation cover, surface moisture, and turbidity) but not pathogens. Our goal was to identify proxies that reliably correlate with Salmonella. Twelve spectral indices (e.g., NDVI, NDWI, and MNDWI) were used as predictors to develop a predictive model for the presence of the pathogen, which achieved 59.2% accuracy. By spatially interpolating the occurrences, it was possible to identify areas with the greatest potential for Salmonella presence. NDWI and AWEI were most strongly correlated with Salmonella presence in high-humidity areas, and spatial interpolation identified the higher-risk zones. These findings reveal the challenges of using remote sensing to identify environmental conditions conducive to the presence of pathogens in surface waters. This study highlights the methodological challenges that must be addressed to make satellite-based surveillance an accessible and effective public health tool. By integrating satellite data with environmental and microbiological analyses, this approach can potentially strengthen low-cost, proactive environmental monitoring for public health decision-making in the context of climate change
Imagen de archivo: Shifu Monogatari
No full textImágenes transferidas sobre papel tejido en telar, técnica japonesa shifu