Hospital Clínico de la Universidad Católica
Pontificia Universidad Católica de Chile: Repositorio UCNot a member yet
70241 research outputs found
Sort by
Cross-species and mammal-to-mammal transmission of clade 2.3.4.4b highly pathogenic avian influenza A/H5N1 with PB2 adaptations
No full textHighly pathogenic H5N1 avian influenza viruses (HPAIV) belonging to lineage 2.3.4.4b emerged in Chile in December 2022, leading to mass mortality events in wild birds, poultry, and marine mammals and one human case. We detected HPAIV in 7,33% (714/9745) of cases between December 2022-April 2023 and sequenced 177 H5N1 virus genomes from poultry, marine mammals, a human, and wild birds spanning >3800 km of Chilean coastline. Chilean viruses were closely related to Peru's H5N1 outbreak, consistent with north-to-south spread down the Pacific coastline. One human virus and nine marine mammal viruses in Chile had the rare PB2 D701N mammalian-adaptation mutation and clustered phylogenetically despite being sampled 5 weeks and hundreds of kilometers apart. These viruses shared additional genetic signatures, including another mammalian PB2 adaptation (Q591K, n = 6), synonymous mutations, and minor variants. Several mutations were detected months later in sealions in the Atlantic coast, indicating that the pinniped outbreaks on the west and east coasts of South America are genetically linked. These data support sustained mammal-to-mammal transmission of HPAIV in marine mammals over thousands of kilometers of Chile's Pacific coastline, which subsequently continued through the Atlantic coastline
Improving the Modeling of Binary Response Regression Based on New Proposals for Statistical Diagnostics With Applications to Medical Data
No full text© 2025 John Wiley & Sons Ltd.Binary regression models utilizing logit or probit link functions have been extensively employed for examining the relationship between binary responses and covariates, particularly in medicine. Nonetheless, an erroneous specification of the link function may result in poor model fitting and compromise the statistical significance of covariate effects. In this study, we introduce a diagnostic method associated with a novel family of link functions enabling the assessment of sensitivity for symmetric links in relation to their asymmetric counterparts. This new family offers a comprehensive model encompassing nested symmetric cases. Our method proves beneficial in modeling medical data, especially when evaluating the sensitivity of the commonly used logit link function, prized for its interpretability via odds ratio. Moreover, our method advocates a general link based on the logit function when a standard link is unsatisfactory. We employ likelihood-based methods to estimate parameters of the general model and conduct local influence analysis under the case-weight perturbation scheme. Regarding local influence, we emphasize the relevance of employing appropriate perturbations to avoid misleading outcomes. Additionally, we introduce a diagnostic method for local influence, assessing the sensitivity of odds ratio under two perturbation schemes. Monte Carlo simulations are conducted to evaluate both the diagnostic method performance and parameter estimation of the general model, supplemented by illustrations using medical data related to menstruation and respiratory problems. The results confirm the efficacy of our proposal, highlighting the critical role of statistical diagnostics in modeling.National Agency for Research and Developmen
Liderazgo intermedio y colaboración pedagógica para la mejora escolar
No full textTesis (Magíster en Educación con mención en Dirección y Liderazgo Educacional)--Pontificia Universidad Católica de Chile, 2025El liderazgo intermedio es un factor clave para impulsar mejoras escolares a través de la colaboración docente, no obstante, su implementación aún presenta desafíos, como son la puesta en marcha de prácticas colaborativas, el tiempo destinado al trabajo entre profesionales, entre otros. Este estudio de “investigación - acción” realizó una intervención en un colegio particular de Santiago para potenciar el rol de la jefa de departamento de matemática y su impacto como líder intermedio en la promoción de prácticas colaborativas a través del modelo del Ciclo de Investigación Colaborativa (CIC). La intervención incluyó talleres, planificaciones conjuntas, observación y retroalimentación de clases, evaluando el impacto en la promoción del trabajo colaborativo y el aprendizaje de los estudiantes. Los principales hallazgos de la investigación dan cuenta de un impacto positivo, resignificando el rol de la jefa de departamento como una líder instruccional que promueve el trabajo colaborativo, la reflexión pedagógica y en consecuencia mejorando prácticas pedagógicas que impactan en el aprendizaje de los y las estudiantes.Palabras claves: “Liderazgo intermedio”, “colaboración docente”, “desarrollo profesional, “Ciclos de Investigación Colaborativa”, “liderazgo instruccional”
Simultaneous liver T1, T2, and ADC MR fingerprinting using optimized motion-compensated diffusion preparations: An initial validation on volunteers
No full textMagnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.Purpose: To develop a novel MR fingerprinting sequence using optimized motion-compensated diffusion preparations for simultaneous T1, T2, and ADC quantification of liver tissue in a single breath-held scan. Methods: A radial spoiled gradient echo acquisition with magnetization preparation modules for T1, T2, and ADC encoding is proposed. To compensate for the signal voids generated by the diffusion preparation, the combination of (1) a breath-held scan, (2) peripheral pulse signal triggering, and (3) an optimized motion-compensated diffusion-preparation module is employed. Phantom experiments were performed to test the accuracy of the technique. The sequence was evaluated in 11 healthy subjects in comparison to conventional mapping techniques. Additional in vivo repeatability assessment experiments were performed. Results: T1, T2, and ADC quantification showed good correlation (r2 > 0.9 for all cases) with reference maps in phantoms and good agreement in vivo against clinical scans (bias not significantly different from zero). A peripheral pulse trigger delay of 200 ms was used to reduce cardiovascular motion artifacts. The repeatability tests prove a low interscan coefficient of variation and a high intraclass correlation coefficient of greater than 0.9 for all cases. Conclusions: Simultaneous quantification of T1, T2, and ADC in liver tissue in a single MR fingerprinting scan of ˜16 s has been proposed, enabling a comprehensive evaluation of hepatic disease through co-registered multiparametric imaging. Further studies are warranted to test this approach in patients with suspected diffuse liver disease to evaluate its potential for liver tissue characterization and tumor staging.ANID/FONDECYT; Folios: 1250261,125025
Short-and Long-Term Mechanical and Durability Performance of Concrete with Copper Slag and Recycled Coarse Aggregate Under Magnesium Sulfate Attack
No full textSustainability in the construction sector has become a fundamental objective for mitigating escalating environmental challenges; given that concrete is the most widely used man-made material, extending its service life is therefore critical. Among durability concerns, magnesium sulfate (MgSO4) attack is particularly deleterious to concrete structures. Therefore, this study investigates the short- and long-term performance of concrete produced with copper slag (CS)—a massive waste generated by copper mining activities worldwide—employed as a supplementary cementitious material (SCM), together with recycled coarse aggregate (RCA), obtained from concrete construction and demolitionwaste, when exposed to MgSO4. CS was used as a 15 vol% cement replacement, while RCA was incorporated at 0%, 20%, 50%, and 100 vol%. Compressive strength, bulk density, water absorption, and porosity were measured after water curing (7–388 days) and following immersion in a 5 wt.% MgSO4 solution for 180 and 360 days. Microstructural characteristics were assessed using scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis with its differential thermogravimetric derivative (TG-DTG), and Fourier transform infrared spectroscopy (FTIR) techniques. The results indicated that replacing 15% cement with CS reduced 7-day strength by ≤10%, yet parity with the reference mix was reached at 90 days. Strength losses increased monotonically with RCA content. Under MgSO4 exposure, all mixtures experienced an initial compressive strength gain during the short-term exposures (28–100 days), attributed to the pore-filling effect of expansive sulfate phases. However, at long-term exposure (180–360 days), a clearstrength decline was observed, mainly due to internal cracking, brucite formation, and thetransformation of C–S–H into non-cementitious M–S–H gel. Based on these findings, thecombined use of CS and RCA at low replacement levels shows potential for producingenvironmentally friendly concrete with mechanical and durability performance comparable to those of concrete made entirely with virgin materials.ANID/Fondecyt Regular 125009
Prolonged intermittent high-volume hemofiltration as kidney replacement therapy in critically ill patients
No full textBackground Prolonged and intermittent high-volume hemofiltration (HVHF) can be performed in extremely critical patients for hemodynamic support. In addition, it can serve as a kidney replacement therapy, given its large ultrafiltration volume. Our objective is to characterize the depuration properties of HVHF and hemodynamic tolerance. Methods This was a retrospective cohort study. All adult critical patients who received HVHF in a university hospital during 2021 were included. Demographic variables, past medical history, pre- and post-HVHF blood tests, and hemodynamic tolerance were evaluated. Results A total of 133 HVHF sessions were performed on 74 critical patients (age 61.1 ± 14.8 years, 43.2% women, and sequential organ failure assessment (SOFA) score 15.5 ± 3.8). All HVHF sessions were performed with prefilter replacement fluid, and 83.5% without anticoagulation. Time (QT) was 337 ± 86 min, with replacement flow rate (QR) at 81 ± 21 mL/kg/h. Hypotension occurred in 19.6% of the procedures at connection and 6.8% during therapy with no precipitating factor. Norepinephrine dose decreased ≥ 20% in 47.1% of the HVHF sessions. Single-pool urea Kt/V (spKt/V) was 0.52 ± 0.17. In HVHF of QT 6–8 h, spKt/V was 0.58 ± 0.17. Higher spKt/V was associated with higher QT and high QR. Post-HVHF sodium was significantly associated with sodium in the replacement fluid. Before HVHF, 18% had hyperkalemia (5.9 ± 1.1 mEq/L). Post-therapy kalemia was 4.8 ± 0.6 mEq/L. Post-HVHF potassium was associated with QR and ultrafiltration. Conclusions Prolonged and intermittent HVHF could serve as an alternative kidney replacement therapy in critically ill patients because it provides adequate control of the internal environment, allows withdrawal anticoagulation, favors patient mobility for procedures and treatments, and provides hemodynamic support
The Wisdom of Greece. The Status of Rhetoric in Emmanuel Levinas͕> PhilosophyLa sabiduría de Grecia. El estatus de la retórica en la filosofía de Emmanuel Levinas
No full text© 2025 Universidad Complutense Madrid. All rights reserved.The aim of this paper is to analyze the rhetoric’s nature in the philosophy of Emmanuel Levinas. It deals with the reflections on politics and language, where the question of the role played by the rhetoric –as a language intended to persuade– in the ethical dimension is seated. In a first approach to this topic the rhetoric corresponds to the politic language of violence and domination. Nevertheless, we will show that a broad interpretation of Latin rhetoric’s nature –from the “movere” in Saint Agustine–coincides with the ethical command: “Thou shalt not kill”.Sara Candiracci and Dasha MoschonasBernard Van Leer Foundatio
Cell wall modifications in Saccharomyces cerevisiae wine yeast through adaptive laboratory evolution with Tebuconazole
No full textSaccharomyces cerevisiae is the most used yeast for wine production around the world. Several characteristics make this yeast the wine yeast of excellence; among them is a great tolerance to higher concentrations of sugar and alcohol. Nevertheless, some compounds could have detrimental effects on its development like pesticides. Tebuconazole is one of the most common fungicides used in agriculture, belonging to the largest group of fungicides, the triazoles chemical group, that act on sterol biosynthesis. Yeasts have different responses to compensate for stress, and changes in their cell wall are one of the main ones. This work aimed to obtain new variants of S. cerevisiae through adaptive laboratory evolution (ALE) using Tebuconazole as selection pressure and to evaluate changes in yeast cell wall structure, composition, and fermentative behavior. Three new variants of S. cerevisiae were obtained. Analysis of the relative expression of genes associated with cell wall components showed that the third variant obtained YCPUC209C, had overexpression of genes FKS1, FKS3, CHS3, and SED1 in comparison with the original strain, also morphological analysis through TEM microscopy showed that YCPUC209C had an increase of 22.2% of cell wall thickness and 19% increase in the amount of glucan in comparison to the original strain. These cell wall changes were accompanied by hypersensitive to β-1,3-glucanase activity. Increased tolerance to pesticides Buprofezin and Spirotetramat presence during alcoholic fermentation was achieved by YCPUC209C, improving fermentative efficiency parameter. Changes in cell wall structure and composition reported in this work open new lines of analysis like the evaluation of yeast pesticide dissipation capacity since it is reported that components, such as glucan and chitin, can bond to these contaminants, reducing their residues in the wine
Mapping advance care planning and advance directives in Latin America
No full textBackground/aims The extent to which low- and middle-income countries have implemented Advance Care Planning (ACP) and Advance Directives (AD) remains unclear. We aimed to map the current status of ACP/AD in Latin America. Methods This cross-sectional, mixed-methods survey of ACP/AD in LA comprised interviews with 18 key informants from 18 out of 20 countries, most of whom were appointed by national Palliative Care Associations. Online interviews were conducted with each informant, covering a range of relevant topics from AD regulations to the use of ACP/AD in the context of end-of-life clinical decision making. We performed member checking and data triangulation to confirm our findings. Results Only eight (44%) countries have some form of ACP/AD regulations. Most regulatory frameworks tend to adopt a legalistic pattern heavily influenced by the North American model. Despite that characteristic of AD regulations in LA, the leading strategy used by patients to avoid unwanted treatment at the end of life is through conversations with their families, whereas the least common strategy was consulting with a lawyer. In six (33%) countries, informants believed it was common for patients to grant their families permission to modify their previous choices regarding future treatments. The religiosity/spirituality of populations play an important role in the implementation of ACP in the region. Additionally, respecting patients’ preferences of care at the end of life appears to be tied more to aspects related to the characteristics of doctor-patient relationship, and the degree of integration of palliative care into the healthcare system than the existence or content of AD regulations. There was consensus that none of the countries provide sufficient education about ACP/AD to healthcare professionals. Conclusions Our findings encourage rethinking ACP/AD in LA from a decolonial perspective, considering characteristics such as the preference for a relational model of autonomy in several countries and the importance of taking the religiosity/spirituality of individuals into account during ACP conversations. Our data also suggest that honoring patients’ preferences of care at the end of life entails integrating palliative care into health care systems, educating healthcare professionals and the population, and fostering longitudinal trusting relationships between those professionals, patients, and their families
Accusations of academic extractivism in Chile's historical poor neighborhoods: root causes and alternative practices
No full textChile's historic poor neighborhoods are attracting increasing academic interest, while residents voice concerns about ‘academic extractivism.’ This criticism highlights researchers’ concentration on these well-studied areas without meaningful engagement with locals. Our paper examines this issue from three perspectives: residents’ experiences with institutions and researchers, and their aspirations for self-representation; pressures of ‘fast science’ that disrupt the relationships between scholars and lower-class communities; and the challenges faced by our research team when implementing a conventional research design in these territories. We conclude emphasizing the need for alternative urban research practices that prioritize collaboration, reciprocity, and the redistribution of power dynamics