Proyectos

The phenomenon of a soft liquid drop eroding a hard stone surface over time, immortalized in the ancient proverb «dripping water wears away the stone,» presents a profound mechanical puzzle. While craters are common imprints of high-energy events, those formed by persistent, low-energy water dripping are exceptional. The impact energy of a single drop is far below the threshold required to plastically deform or fracture the material, yet erosion occurs. This project seeks to answer the fundamental question: How can water erode stone through dripping and create distinctive craters? While recent advancements in drop-impact dynamics have revealed that an impacting drop generates propagating fronts of intense, singular pressure and shear, these theories were developed for ideal, non-porous surfaces and are insufficient to explain the erosion. Our preliminary experimental work—which has successfully reproduced water-dripping craters on gypsum targets while failing to erode non-porous materials—points to a crucial, previously overlooked element: the porous nature of the target material. We discovered that erosion and the formation of a distinct surface microstructure of pores commence only after the substrate becomes fully saturated with water. This key finding suggests that the complex interaction between the impact-induced flow and the internal, liquid-filled pore structure is the primary driver of the erosion mechanism. This project will establish the first comprehensive experimental and theoretical framework for slow erosion in porous ma- terials by water dripping. We will investigate three potential and non-exclusive micro-mechanisms. The first is low-Reynolds accumulative erosion, where the impact pressure pumps liquid into the matrix, generating high shear stress along pore walls that slowly abrades material, a process whose rate is expected to be proportional to the wall shear stress. The second is the inter-pore propagation of pressure shocks; because the surface pressure front arrives at adjacent pore openings at slightly different times, large pressure gradients are generated within the saturated matrix, inducing mechanical fatigue and failure of inter-pore walls. The third is cavitation bursts, where the negative-pressure front trailing the initial impact shock— akin to an explosion’s blast wave—causes the formation and violent collapse of vapor bubbles. These collapses generate localized but highly destructive shock waves, a process potentially detectable via acoustic emissions. Our methodology integrates a novel, multi-scale experimental approach with robust theoretical modeling. An automated, custom-built setup, featuring a syringe pump for precise drop control and a photo-gate for impact counting and synchroniza- tion, tracks crater evolution over tens of thousands of reproducible impacts. An automated translation stage will move the sample between the impact zone and a characterization chamber for on-the-run 3D shape reconstruction via high-resolution laser profilometry and for mass measurement via an integrated load cell. This will be complemented by a suite of characteriza- tion techniques, including high-speed imaging to capture rare ejecta events, microscopic surface imaging, and advanced bulk imaging (X-ray Micro-Tomography, Scanning Electron Microscopy or Nuclear Magnetic Resonance) to visualize the internal 3D pore network and wear propagation. Experiments will mainly utilize natural materials like gypsum and selenite, as well as custom-fabricated synthetic porous samples (e.g., PDMS). These transparent, engineered samples will allow for direct flow visualization via Particle Image Velocimetry (PIV) to isolate and study specific mechanisms in a controlled environment. The theoretical work will couple established models for drop-impact pressure distributions with frameworks for flow in porous media, wall-shear erosion, and wave propagation. The goal is to develop predictive formulae for crater growth rates and their scaling with fluid and material properties, which can be validated against our extensive experimental data. By leveraging the research team’s expertise in drop-impact forces and tackling this 2,500-year-old question, this project will provide novel insights into fluid-solid interactions, wear on porous materials, and landscape evolution. It moves beyond prior studies, which used simplified substrates, to address the central role of porosity in this long-unsolved problem in continuum physics.

Postulación a Fondecyt Regular

Game theory and artificial intelligence are deeply connected fields, particularly when model- ing adversarial learning problems as Stackelberg games under uncertainty. In such settings, defenders allocate resources randomly to prevent attackers from anticipating their moves. As time evolves, the environment changes, and new strategies or actions may emerge. A suitable subfield of game theory to model these dynamics is stochastic games, where the state captures the set of available actions in a time-dependent process. Moreover, the attacker–defender inter- action naturally exhibits a hierarchical bilevel structure: the defender must design randomized strategies to protect targets, while the attacker responds by executing an action that maxi- mizes its reward. This makes stochastic dynamic Stackelberg games a model of choice for such applications [15], the Chilean party being very active in the domain [9, 10, 11]. In a previous collaboration [1], we have shown that defining an appropriate solution concept for these games is far from trivial, and in some cases remains an open research question. Even when a proper solution concept can be established, computing it becomes prohibitively expensive for games with massive state and action spaces. These challenges are not only of theoretical interest but also of high practical relevance. This associate team will focus on two among the many possible applications. Challenge 1: The first one is wildfire prevention. This theme has been widely examined in the literature, particularly through models that optimize the design of firebreaks [16], [12] and the the placement of surveillance cameras to limit fire spread. In contrast, the operational dimension of prevention and firefighting—where resources must be dynamically allocated un- der uncertainty—has received far less attention. Emerging distributed AI technologies with autonomous agents, both centralized (e.g., coordinated command-and-control systems) and de- centralized (e.g., drones and sensor swarms), could play a key role in addressing this challenge. Challenge 2: Similarly, in the domain of distributed AI learning systems (e.g. Federated Learning), a central authority is in charge of agregating the updates of distributed clients in the process of minimizing a global metric. The presence of Byzantine (or faulty) agents can derail convergence or induce a biais in this process. To mitigate this, robust agregation techniques have been proposed in the literature based on identifying and discarding suspect contributions [17, 18, 19]. But concrete attacks like ALIE [20] or FoE [21] tend to exhibit patterns. This lead researchers to propose the first history-aware defenses [22, 23, 24]. Purely deterministic rules, though, are likely to be defeated by powerful and well-informed agents. The attacker–defender framework is crucial to design secure training environments against adversarial manipulations, the principal issue being to decide if and when to exclude a suspected malicious agent. Both these applications can be tackeled with tools of Game Theory. More applications could be cited, like environmental conservation problems, such as poaching prevention [25], environmental tax evasion [26] or border patrol security [9].

The rapid increase in immigration and the presence of different Indigenous peoples in the country have resulted in culturally diverse classrooms in Chile. Cultural differences are significant for communication (Otten & Geppert, 2009) and teaching processes (Liddicoat & Scarino, 2013). Hence, intercultural interactions correspond to embodied culture discourses (Carbaugh, 2017; Shi-xu, 2023), which entail the communication practices that take place at institutional levels (i.e., top-down) and language classrooms (i.e., bottom-up). However, some tensions have been identified in these processes, particularly because they seem to maintain cultural and linguistic hierarchies that do not necessarily promote the social mobility or acceptance of minoritized groups (Flores & Rosa, 2015; Unamuno, 2016; Zavala, 2017). Against this backdrop, discursive practices are at the core of how these raciolinguistic hierarchies are maintained, negotiated, and/or challenged by educational communities. Consequently, the main objective of this research proposal is to examine how language and interculturality are discursively conceptualized and implemented in culturally diverse Chilean schools, specifically within three language subjects: Spanish, Ancestral Languages, and English as a Foreign Language. This objective is articulated through the following research question: How are language and interculturality discursively conceptualized and implemented in culturally diverse Chilean schools across the subjects of Spanish, Ancestral Languages, and English as a Foreign Language? To address this question, the project outlines four specific objectives (SOs): SO1) To examine how interculturality is discursively constructed in educational policies and the national curriculum on language subjects (i.e., Spanish, Ancestral Languages, and English as a Foreign Language); SO2) To assess how language teachers understand and implement intercultural practices in Chile, highlighting areas of convergence and divergence; SO3) To analyze how school communities discursively construct interculturality on their schoolscapes; and SO4) To analyze how language teachers’ actions and decisions address interculturality in the language classroom. The proposed research is a mixed-methods study (Creswell & Plano, 2018). First, we will analyze a corpus of institutional pedagogical discourses to examine how interculturality is discursively constructed in educational policies and the national curriculum (SO1). To this end, the data will be examined from a Corpus-Assisted Approach to Discourse Studies (CADS) (Partington et al., 2013) following the guidelines proposed by Jaworska and Kinloch (2018, p. 116) for a thorough and systematic examination of multiple datasets in CADS. The first quantitative stage considers the analysis of frequency, concordance lines, collocations, and keywords. The second qualitative stage is informed by Bacchi's (2012) model, What's the Problem Represented to be? (or WPR) and the Discourse-Historical Approach (Reisigl, 2017; Reisigl & Wodak, 2016). Second, we will conduct a questionnaire to identify how language teachers understand interculturality and intercultural practices in their classrooms (SO2). The sampling considers a disproportionate stratification to enable similar sample sizes for Spanish and EFL teachers, and Traditional Educators, ensuring the representation of Traditional Educators, who are the smallest population (CEM Mineduc, 2024). Third, we will analyze how school communities discursively construct interculturality on their school grounds (SO3) through the examination of schoolscapes (Gorter & Cenoz, 2015). To this end, three schools across three regions will be selected (i.e., Tarapacá, Metropolitan, and Araucanía) to ensure geographic representativeness. The data will be analyzed in light of Ledin and Machin’s multimodality framework (2017, 2018, 2019) as it incorporates the materiality of the semiotic signs, the ideologies and beliefs behind the creation of multimodal texts, and the recontextualization of social actors and practices (van Leeuwen, 2008). Finally, we analyze the actions and decisions language teachers take to address interculturality in the language classroom (SO4) through classroom observation (minimum 48 pedagogical hours in total; four hours per language subject) in the same schools. These observations will be analyzed using the synopsis technique (Dolz et al., 2018; Schneuwly & Dolz, 2009), which allows us to both hierarchize central pedagogical sequences and examine teachers' actions and students' reactions in detail. In turn, it enables data reduction and serves as heuristic support for analysis. Expected results seek to enlighten how educators co-create language and interculturality in culturally diverse schools. It examines how these social actors recontextualize and mediate top-down policies to their daily realities, thus illuminating the negotiation and resemiotization of hegemonic understandings of interculturality in line with the needs of their own communities (bottom-up practices).

Objetivo general: Examinar los procesos de convivencia intercultural y describir los discursos y prácticas escolares sobre la producción de diferencias étnicas y migrantes en dos escuelas secundarias chilenas diversas en la Región de O'Higgins y en la Región Atacama.

In this project, police empowerment is preliminarily defined as the process by which police forces are granted powers or see their existing powers expanded through legal mandates (e.g., laws that grant police forces with more attributions or discretion), institutional and administrative capacities (e.g., budget increase), and social perceptions (e.g., citizens’ and authorities’ perceptions and support for police empowerment, as well as police officers’ self-empowerment). Existing research has largely focused on isolated dimensions of this process—either legal, institutional, or perceptual—but has not addressed how these interact or differ in their consequences. This project addresses this gap by (a) proposing a multidimensional, contextually grounded, conceptual and operational definition of police empowerment and analyzing how its different components—moderated by accountability—affect public security and order, and the potential for police abuse. To achieve these goals, we adopt a multi-method design composed of six interrelated studies. These include expert interviews (Study 1), a longitudinal panel survey with citizens (EPSEP, Study 2), secondary data analysis (legal, institutional/administrative and authorities’ discourse analysis, Study 3), interviews with police officers (Study 4), a quasi-experimental study of the effect of key moments of empowerment (e.g., the enactment of a new law increasing police power, Study 5) on the aforementioned consequences, and an experimental study with police personnel (Study 6). Study 2 will also enable longitudinal, quasi- experimental (via a rolling cross-sectional design), and experimental analyses of the effects of police empowerment among citizens.

El objetivo principal de este proyecto es actualizar y profundizar el conocimiento sobre la distribución y prevalencia de triatominos vectores de Trypanosoma cruzi en la Región de O’Higgins, Chile. Esto se realizará a través del análisis de datos históricos y actuales de entidades de salud, complementado con muestreos intensivos de mamíferos silvestres y monitoreo de animales domésticos en áreas identificadas como de alto riesgo. Se explorarán además los focos históricos y zonas predichas como aptas para la presencia de triatominos, utilizando avanzadas técnicas de detección molecular y análisis de modelación. Este estudio busca no solo llenar un vacío de conocimiento sobre la presencia de estos vectores, sino también evaluar cómo los cambios climáticos y antrópicos podrían estar alterando su distribución geográfica, afectando así el riesgo de transmisión de la enfermedad de Chagas en la región.

Esta investigación busca conocer las formas en que las escuelas se pueden desempeñar como espacios culturales en sus comunidades locales, para lo cual se analizarán cómo las prácticas artísticas de mediación expandida se muestrán como una herramienta y metodología idónea para su desarrollo e impacto local.

El borde costero de la región de O’Higgins enfrenta un desafío importante en cuanto a alcanzar un desarrollo sostenible a nivel ambiental. Esto se debe a la exposición a contaminantes como pesticidas y metales provenientes de actividades clave de la región, como lo son la agricultura y la minería. Esta contaminación amenaza los ecosistemas del borde costero, la biodiversidad, la salud pública y las actividades económicas fundamentales como la pesca artesanal y el turismo. A pesar de la magnitud del problema, existe escasa información sobre los contaminantes presentes en este ambiente. La ausencia de sistemas de monitoreo limita la caracterización de la presencia de contaminantes y la evaluación de sus efectos sobre los ecosistemas costeros. Esta brecha dificulta la implementación de estrategias efectivas de gestión ambiental y pone en riesgo la sostenibilidad de las comunidades costeras que dependen de estos recursos naturales. El proyecto propone desarrollar una herramienta de biosurveillance adaptada a las características específicas del borde costero regional, inspirada en el exitoso modelo francés BIOSURVEILLANCE que utiliza organismos centinelas para evaluar la calidad del agua. La iniciativa busca establecer un sistema piloto de monitoreo que combine análisis químicos de contaminantes con evaluación de biomarcadores inmunológicos en mejillones, organismos filtradores que bioacumulan contaminantes y que sirven como reflejo del estado de salud del ecosistema. El objetivo general del proyecto es evaluar el estado de salud inmunológico de organismos centinela del borde costero de la Región de O'Higgins y su relación con la presencia de contaminantes, desarrollando un piloto de biosurveillance transferible a la gestión ambiental y acuicultura. Este proyecto cuenta con cuatro objetivos específicos: (1) caracterizar la presencia y concentración de contaminantes persistentes (metales y pesticidas) en agua, sedimentos y biota; (2) evaluar las respuestas inmunológicas en organismos centinela mediante biomarcadores moleculares; (3) analizar la relación entre contaminantes específicos y respuestas inmunológicas para identificar biomarcadores sensibles y robustos; y (4) desarrollar un piloto de biosurveillance con potencial de transferencia a programas de gestión regional y nacional. Para llevar a cabo este proyecto se implementará un sistema de encajonamiento de mejillones (Mytilus edulis o M. chilensis) en tres sitios estratégicos del borde costero: Navidad, Pichilemu y Bucalemu. Estos sitios representan puntos críticos de confluencia entre aportes continentales y ecosistema marino, permitiendo evaluar efectos acumulativos de contaminación. Se realizarán dos campañas de muestreo (invierno y verano) para capturar variación temporal. En cada sitio se colocarán individuos adultos en jaulas durante 15 días, período tras el cual se recuperarán para análisis químicos y biológicos. El componente químico incluirá análisis de metales mediante espectrometría (ICP-OES) y pesticidas mediante cromatografía (LC-MS/MS) en matrices de agua, sedimentos y tejidos. Paralelamente, se caracterizarán parámetros fisicoquímicos (pH, conductividad, temperatura, oxígeno disuelto, salinidad) para contextualizar biogeoquímicamente los sitios. El componente biológico evaluará biomarcadores de respuesta inmune mediante análisis de expresión génica por qPCR de genes relacionados con estrés oxidativo (catalasa, superóxido dismutasa, glutatión S-transferasa, metalotioneínas) en tejidos de mejillones. Estos biomarcadores son sensibles a la exposición a metales y pesticidas, proporcionando indicadores tempranos de estrés ambiental. La integración de datos químicos y biológicos se realizará mediante análisis estadísticos multivariados y matrices de correlación utilizando lenguaje de programación (Phyton y R), identificando relaciones causales entre contaminantes específicos y activación del sistema inmune. Esta aproximación permitirá seleccionar los biomarcadores más apropiados según ubicación geográfica y estacionalidad, estableciendo las bases para un sistema de alerta temprana aplicable a la gestión costera regional. El proyecto tiene una duración de 18 meses y representa una iniciativa interdisciplinaria que integra Ciencias del Medio Ambiente, Biología Marina y Matemática Aplicada, contribuyendo directamente a la sostenibilidad ambiental del borde costero regional y generando conocimiento transferible para futuros programas de monitoreo a escala nacional.

El borde costero de la región de O’Higgins enfrenta un desafío importante en cuanto a alcanzar un desarrollo sostenible a nivel ambiental. Esto se debe a la exposición a contaminantes como pesticidas y metales provenientes de actividades clave de la región, como lo son la agricultura y la minería. Esta contaminación amenaza los ecosistemas del borde costero, la biodiversidad, la salud pública y las actividades económicas fundamentales como la pesca artesanal y el turismo. A pesar de la magnitud del problema, existe escasa información sobre los contaminantes presentes en este ambiente. La ausencia de sistemas de monitoreo limita la caracterización de la presencia de contaminantes y la evaluación de sus efectos sobre los ecosistemas costeros. Esta brecha dificulta la implementación de estrategias efectivas de gestión ambiental y pone en riesgo la sostenibilidad de las comunidades costeras que dependen de estos recursos naturales. El proyecto propone desarrollar una herramienta de biosurveillance adaptada a las características específicas del borde costero regional, inspirada en el exitoso modelo francés BIOSURVEILLANCE que utiliza organismos centinelas para evaluar la calidad del agua. La iniciativa busca establecer un sistema piloto de monitoreo que combine análisis químicos de contaminantes con evaluación de biomarcadores inmunológicos en mejillones, organismos filtradores que bioacumulan contaminantes y que sirven como reflejo del estado de salud del ecosistema. El objetivo general del proyecto es evaluar el estado de salud inmunológico de organismos centinela del borde costero de la Región de O'Higgins y su relación con la presencia de contaminantes, desarrollando un piloto de biosurveillance transferible a la gestión ambiental y acuicultura. Este proyecto cuenta con cuatro objetivos específicos: (1) caracterizar la presencia y concentración de contaminantes persistentes (metales y pesticidas) en agua, sedimentos y biota; (2) evaluar las respuestas inmunológicas en organismos centinela mediante biomarcadores moleculares; (3) analizar la relación entre contaminantes específicos y respuestas inmunológicas para identificar biomarcadores sensibles y robustos; y (4) desarrollar un piloto de biosurveillance con potencial de transferencia a programas de gestión regional y nacional. Para llevar a cabo este proyecto se implementará un sistema de encajonamiento de mejillones (Mytilus edulis o M. chilensis) en tres sitios estratégicos del borde costero: Navidad, Pichilemu y Bucalemu. Estos sitios representan puntos críticos de confluencia entre aportes continentales y ecosistema marino, permitiendo evaluar efectos acumulativos de contaminación. Se realizarán dos campañas de muestreo (invierno y verano) para capturar variación temporal. En cada sitio se colocarán individuos adultos en jaulas durante 15 días, período tras el cual se recuperarán para análisis químicos y biológicos. El componente químico incluirá análisis de metales mediante espectrometría (ICP-OES) y pesticidas mediante cromatografía (LC-MS/MS) en matrices de agua, sedimentos y tejidos. Paralelamente, se caracterizarán parámetros fisicoquímicos (pH, conductividad, temperatura, oxígeno disuelto, salinidad) para contextualizar biogeoquímicamente los sitios. El componente biológico evaluará biomarcadores de respuesta inmune mediante análisis de expresión génica por qPCR de genes relacionados con estrés oxidativo (catalasa, superóxido dismutasa, glutatión S-transferasa, metalotioneínas) en tejidos de mejillones. Estos biomarcadores son sensibles a la exposición a metales y pesticidas, proporcionando indicadores tempranos de estrés ambiental. La integración de datos químicos y biológicos se realizará mediante análisis estadísticos multivariados y matrices de correlación utilizando lenguaje de programación (Phyton y R), identificando relaciones causales entre contaminantes específicos y activación del sistema inmune. Esta aproximación permitirá seleccionar los biomarcadores más apropiados según ubicación geográfica y estacionalidad, estableciendo las bases para un sistema de alerta temprana aplicable a la gestión costera regional. El proyecto tiene una duración de 18 meses y representa una iniciativa interdisciplinaria que integra Ciencias del Medio Ambiente, Biología Marina y Matemática Aplicada, contribuyendo directamente a la sostenibilidad ambiental del borde costero regional y generando conocimiento transferible para futuros programas de monitoreo a escala nacional.