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JUE insight: Efficiency of bus priority infrastructure
No full textWe use bus GPS data across 500 routes to estimate the impact of priority infrastructure on buses’ speed and ridership in Chile. Almost 100 million bus trips allow us to leverage within-route variation in the proportion of the route in which buses travel along bus lanes or Bus Rapid Transit (BRT) corridors. Corridors increase bus speeds by 20% at peak hours. Bus lanes, often seen as an equally effective but cheaper alternative to a BRT corridor, are, on average, ineffective. However, bus lanes achieve the same travel time savings as BRT corridors only when fully isolated from private vehicles, coupled with monitoring cameras and enforcement.ANID/FONDECYT; Folio de beca: 124173
Predicciones de supervivencia celular a través de machine learning
No full textTesis (Magíster en Física Médica)--Pontificia Universidad Católica de Chile, 2025La radioterapia con protones e iones pesados es un tratamiento eficaz contra el cáncer, por esto comprender su impacto a nivel biológico es esencial para optimizar su efectividad. Predecir los efectos biológicos de la radiación, que dependen de las condiciones de irradiación y la complejidad del daño al ADN, sigue siendo un desafío importante, especialmente en distribuciones de dosis como las usadas con partículas pesadas.En este trabajo se desarrollaron modelos de aprendizaje automático para hacer predicciones de supervivencia celular in-vitro. El trabajo principal fue enfocado en modelos para predicciones con partículas pesadas, también se entrenaron modelos similares para experimentos con fotones. A la vez, se combinaron simulaciones Monte Carlo con los modelos para hacer predicciones de supervivencia en profundidad, a partir de una distribución de dosis simulada de protones.Los modelos fueron entrenados usando una base de datos que recopila experimentos in-vitro de la literatura, en particular se usaron datos de 923 experimentos que abarcan 130 líneas celulares y 26 iones distintos. Se usó un número limitado de variables, que considera el tipo de célula y parámetros físicos como la dosis, energía y tipo de ion.Los modelos entrenados alcanzaron un coeficiente de determinación superior a 0.8 en el conjunto de prueba y en el conjunto de validación externa. Asimismo, al combinar los modelos con simulaciones Monte Carlo, fue posible replicar la disminución en la supervivencia celular en una configuración compleja.Este trabajo demuestra que es factible combinar modelos de aprendizaje automático con Monte Carlo, y dada la pequeña cantidad de variables utilizadas, es fácil de implementar en entornos experimentales, proporcionando una alternativa a otros modelos existentes.La radioterapia con protones e iones pesados es un tratamiento eficaz contra el cáncer, por esto comprender su impacto a nivel biológico es esencial para optimizar su efectividad. Predecir los efectos biológicos de la radiación, que dependen de las condiciones de irradiación y la complejidad del daño al ADN, sigue siendo un desafío importante, especialmente en distribuciones de dosis como las usadas con partículas pesadas. En este trabajo se desarrollaron modelos de aprendizaje automático para hacer predicciones de supervivencia celular in-vitro. El trabajo principal fue enfocado en modelos para predicciones con partículas pesadas, también se entrenaron modelos similares para experimentos con fotones. A la vez, se combinaron simulaciones Monte Carlo con los modelos para hacer predicciones de supervivencia en profundidad, a partir de una distribución de
dosis simulada de protones. Los modelos fueron entrenados usando una base de datos que recopila experimentos invitro de la literatura, en particular se usaron datos de 923 experimentos que abarcan 130 líneas celulares y 26 iones distintos. Se usó un número limitado de variables, que considera
el tipo de célula y parámetros físicos como la dosis, energía y tipo de ion. Los modelos entrenados alcanzaron un coeficiente de determinación R2 superior a 0.8 en el conjunto de prueba y en el conjunto de validación externa. Asimismo, al combinar los modelos con simulaciones Monte Carlo, fue posible replicar la disminuci´on en la supervivencia celular en una configuraci´on compleja.
Este trabajo demuestra que es factible combinar modelos de aprendizaje autom´atico con
Monte Carlo, y dada la pequeña cantidad de variables utilizadas, es fácil de implementar en entornos experimentales, proporcionando una alternativa a otros modelos existentes
A detailed multi-component heat configuration assessment for complex industrial plants through Monte Carlo simulations: a case study for the cement industry
No full textThe decarbonization of industrial plants involves the integration of cleaner and more efficient energy processes, which might include electrification, renewable energy sources, waste heat recovery, and thermal energy storage. The technical viability of each assisting technology is usually assessed through direct simulations of the integrated system, which makes evaluation often difficult. This study proposes a methodology for estimating the heat demands of different configurations of a generic cement plant, aiming to assess the fuel consumption for the several integration cases considered. The waste heat and the mass flow rate of the internal streams are considered variable parameters, which lead to 32 distinct integration cases and 16,000 plant simulations. The operating conditions are generated through a Monte Carlo approach, ensuring the probability distribution of the results. The waste heat measures increase the plant’s heat demand and hinder its efficiency. A linear regression for fuel heat demand shows results ranging from 113.72MW to 492.62M
Correction to: Screening for indole-3-acetic acid synthesis and 1-aminocyclopropane-carboxylate deaminase activity in soil yeasts from Chile uncovers Solicoccozyma terrea as an effective plant growth promoter
No full textRelationship between skin microvascular blood flow and capillary refill time in critically ill patients
No full textBackground Capillary refill time (CRT) and skin blood flow (SBF) have been reported to be strong predictors of mortality in critically ill patients. However, the relationship between both parameters remains unclear. Methods We conducted a prospective observational study in a tertiary teaching hospital. All patients older than 18 years admitted in the intensive care unit (ICU) with circulatory failure and a measurable CRT were included. We assessed index SBF by laser doppler flowmetry and CRT on the fingertip, at T0 (Within the first 48 h from admission) and T1 (4 to 6 h later). Correlation was computed using Spearman or Pearson’s formula. Results During a 2-month period, 50 patients were included, 54% were admitted for sepsis. At baseline median CRT was 2.0 [1.1–3.9] seconds and median SBF was 46 [20–184] PU. At baseline SBF strongly correlated with CRT (R2 = 0.89; p < 0.0001, curvilinear relationship), this correlation was maintained whether patients were septic or not (R2 = 0.94; p = 0.0013; R2 = 0.87; p < 0.0001, respectively), and whether they received norepinephrine or not (R2 = 0.97; p = 0.0035; R2 = 0.92; p < 0.0001, respectively). Between T0 and T1, changes in SBF also significantly correlated with changes in CRT (R2 = 0.34; p < 0.0001). SBF was related to tissue perfusion parameters such as arterial lactate level (p = 0.02), whilst no correlation was found with cardiac output. In addition, only survivors significantly improved their SBF between T0 and T1. SBF was a powerful predictor of day-28 mortality as the AUROC at T0 was 85% [95% IC [76–91]] and at T1 90% [95% IC [78–100]]. Conclusion We have shown that index CRT and SBF were correlated, providing evidence that CRT is a reliable marker of microvascular blood flow. Trial registration Comité de protection des personnes Ouest II N° 2023-A02046-39
Adaptación transcultural y validación de un cuestionario genérico de aceptabilidad al español
No full textTo adapt and validate the generic TFA acceptability questionnaire to Spanish. Methods. In the initial phase of this two-phase observational study, a translation and adaptation of the original instrument was performed. The second phase con-sisted of applying this version to 194 older adults after a pilot hearing screening and a standard preventive medical examination. Construct validity was assessed by Exploratory Factor Analysis, and internal consistency with McDonald’s omega (ω). Results. Both procedures yielded the same two-factor solution. The first factor comprised items related to “affective attitude”, “perceived effectiveness”, “inter-vention coherence”, and “self-efficacy”; the second factor included items on “ethi-cality” and “opportunity costs”. The item ‘burden’ was removed due to its lack of significant factor loadings. The first factor accounted for 18.96% of the variance of the hearing screening and 26.28% of the preventive medical examination; the second accounted for 14.97% and 20.44%, respectively. Regarding reliability, the instrument demonstrated an ω = 0.61 for the hearing screening and ω = 0.73 for the preventive medical examination. Conclusion. The final instrument comprises six items evaluating specific acceptability constructs and one item addressing overall acceptability. It features a two-factor underlying structure, demonstrating high external reliability and acceptable internal consistency
Dresses and ties: the effect of grammatical gender and stereotypical semantic bias in three Spanish-speaking communities
No full textStereotype construction is a complex process, with multiple relations to language processing, that combines collective sociocultural factors with individual cognitive elements. Regarding gendered languages, there is a debate about the effect of grammatical gender on the representation of inanimate entities. To evaluate the potential interaction between gender stereotypes and gender morphology on words that refer to inanimate entities in three different communities of Spanish speakers, we developed a task of conscious judgments on the level of association to men or women of words that refer to objects. In a 3 × 2 × 3 × 2 design, we manipulated Semantic Bias (gender stereotypicality), with three levels (male, e.g., martillo, hammer-M; female, e.g., vestido, dress-M; neutral, e.g., lápiz, pencil-M); Morphology, with two levels (masculine, e.g., vestido, dress-M; feminine, e.g., pulsera, bracelet-F); Linguistic variety, with three levels (Argentine, Chilean and Peninsular) and Questionnaire, with two levels (related to men vs. related to women). The results showed that grammatical gender has an effect on words that refer to inanimate entities when those words do not carry a strong stereotypical association (neutral items), semantic bias related to gender stereotypes overshadows any potential effect of grammatical gender in biased items, and there are differences depending on the community (Argentine, Chilean and Peninsular)
Distance simulation in surgical education
No full textDistance and remote simulation have emerged as vital tools in modern surgical education, offering solutions to challenges such as limited operating hours, growing clinical demands, and the need for consistent, high-quality training. This review examines the benefits, limitations, and strategies for implementing sustainable distance simulation, structured around 3 foundational pillars: (1) effective hardware and infrastructure, including simulators and realistic scenarios that enable trainees to develop essential skills; (2) validated training programs grounded in educational theory with a clear focus on skill transfer and predictive validity; and (3) timely access to effective feedback. Distance simulation permits adaptable, scalable training environments, but the addition of remote and deferred feedback has further broadened its impact, helping to overcome the challenges posed by faculty availability and clinician time constraints. Remote-asynchronous feedback not only makes teaching time more efficient but also allows instructors to organize their time flexibly, maximizing their impact. Furthermore, web-based feedback oriented platforms facilitate the creation of a sustainable teaching network through train-the-trainer initiatives, enabling near-peer and nonclinical experts to provide standardized, high-quality teaching. This scalable model reduces the reliance on senior faculty, building a culture of mentorship and support within the surgical education community. In addition, distance simulation platforms are increasingly incorporating artificial intelligence–enhanced assessment tools capable of detecting errors, analyzing procedural steps, and generating automated feedback. Integrating artificial intelligence into innovative simulation modalities not only enhances access to quality feedback but also could provide deeper insights into the learning process, as learners progress through these enriched learning curves. Growing evidence shows how tools for sustainable distance simulation can positively impact education at multiple levels, benefiting undergraduate and postgraduate students, residents, and faculty across a spectrum of skills from basic tasks to complex surgical procedures. Moreover, its applications extend beyond simulated environments, providing frameworks that can be adapted to teach real surgical performance in clinical settings. As surgical education evolves, distance simulation demonstrates immense value in supporting accessible, high-quality training, particularly in resource-limited environments
Influence of grape quality tier, harvest timing, and yeast strain on mannoprotein content, phenolic composition, and color modulation in young red wines
No full textBesides the impact of harvest timing and grape quality, this study investigated the performance of selected yeast strains overproducing mannoproteins versus the conventional strain AGL 804 in terms of mannoprotein release and its consequences on the composition and color modulation of short-aged commercial red wines. The study fills a gap of volume and actual red wine production by comparing 36 winemaking conditions, each of 850 kg of grapes. The results showed that AGL 804 produced the same or more concentration of mannoproteins than the alternatives. Then, an apparent threshold was found for all yeasts when the dissolved solids content of grape musts at harvest exceeded 22 °Bx, beyond which no increase in mannoprotein production was observed. Only below this limit, an independent effect of yeast strains on tannin concentration and tannin-to-anthocyanin ratio (T/A) in wines was observed. These two parameters exhibited a moderate correlation with mannoprotein concentration (R2 = 0.534 and R2 = 0.696, respectively), and a low-moderate correlation for mannoprotein concentration with CIELAB color parameters. Wines produced from grapes > 22 °Bx showed only harvest-related variations in tannin concentration and T/A and no correlation between parameters analyzed and mannoprotein production. The study revealed that, although yeast strains influence the color of red wine after six months of bottling, their effect is secondary to the harvest timing. Moreover, the influence of the yeast strain itself was not consistent across the different harvest dates. Additionally, the study provides winemakers with an improved and practical assay for measuring mannoprotein levels in red wines, especially for small winery laboratories. It also introduces a novel 3D graphical representation of the CIELAB color parameters, which simultaneously integrates the real visible color of the wines and its visual discriminability to the human eye
La temperatura de la educación: efectos del calor en la educación escolar chilena
No full textTesis (Magíster en Políticas Públicas y Título de Ingeniera Civil de Industrias)--Pontificia Universidad Católica de Chile, 2024This study provides the first evidence from Chile on how accumulated heat exposure during the school year affects learning outcomes. Using data from Chilean primary schools from 2002 to 2018, I examine how higher temperatures impact academic performance in SIMCE. I find that exposure to warmer temperatures above 26°C on school days reduces mathematics scores. The effect is more pronounced in the central zone (Csa climate), where schools show significant declines in performance, while schools in the northern zone (Bsk climate) show no effect. This suggests that acclimatization plays a key role in how heat impacts learning. My findings highlight the importance of considering the local climatic context when developing educational policies to adapt to rising temperatures due to climate change