Hospital Clínico de la Universidad Católica
Pontificia Universidad Católica de Chile: Repositorio UCNot a member yet
70241 research outputs found
Sort by
On the limits of knowledge and the evolution of the physical laws in non-Euclidean universes
No full textThe anthropic principle suggests that the universe's fundamental constants are precisely fine-tuned to allow for life. However, by incorporating a dynamic physical perspective of nature, such as the multiscale thermodynamic principle known as Principium Luxuriæ, it is found that fundamental constants and forces of the universe may evolve over time in a non-Euclidean universe. If the universe has this geometry, it would have profound implications, which are discussed in this paper. For example, that the conditions conducive to life are not static and finely tuned but rather transient, undermining the need for a fine-tuned universe. Given that multiscale thermodynamics requires external forces, it's plausible that the universe's expansion could be linked to the existence of other phenomena such as other universes acting as external forces, each with their own evolving laws of physics. This suggests that life might be a transient and coincidental occurrence across multiple universes, if they exist. Additionally, the ever-evolving physical laws limit our ability to fully comprehend the universe at any given time. As we inevitably overlook certain aspects of reality, physical systems cannot be fully explained by the sum of their parts. Consequently, emergent phenomena like consciousness could not be studied from a self-referential perspective, as there will always be elements beyond our understanding
The Role of Organizations in Networked Mobilization: Examining the 2011 Chilean Student Movement Through The Logic of Connective Action
No full textThis study examines the communication mechanisms that shape the formation of digitally-enabled mobilization networks. Informed by the logic of connective action, we postulate that the emergence of networks enabled by organizations and individuals is differentiated by network and framing mechanisms. From a case comparison within two mobilization networks—one crowd-enabled and one organizationally-enabled—of the 2011 Chilean student movement, we analyze their network structures and users’ communication roles. We found that organizationally-enabled networks are likely to form fromhierarchical cascades and crowd-enabled networks are likely to form from triadic closure mechanisms. Moreover, we found that organizations are essential for both kinds of networks: compared to individuals, organizations spread more messages among unconnected users, and organizations’ messages are more likely to be spread. We discuss our findings in light of the network mechanisms and participation of organizations and influential users
The complexity of a “simple” predator–prey system: non-trophic positive interactions generate unsuspected dynamics and dependencies
No full textIn natural ecosystems, many species engage simultaneously in both trophic and non-trophic interactions (NTIs), influencing each other's population growth and patterns of local coexistence. However, in coastal marine systems, where the larvae of most benthic adults disperse and frequently settle into populations distant from their origin, populations do not experience feedback from local reproduction. This implies an apparent decoupling between local dynamics and regional-scale dispersal processes. Here, we explore the consequences of positive NTIs for the coexistence and dynamics of a predator and its prey. Inspired by two species studied in the Chilean intertidal zone, we developed a predator–prey model in which the prey also facilitates the recruitment of and provides refuge to the predator, while larval subsidies externally control the population growth of both species. The predator–prey dynamic was simulated at different levels of species recruitment, with and without NTIs. Overall, NTIs led to density dependence of the predator on the prey, coupling their abundances across varying levels of larval subsidies. Furthermore, the impact of NTIs on predator abundance was non-additive, with the magnitude of these effects depending on recruitment rates. In addition to determining population growth, recruitment rates also modulate the extent to which the predator is facilitated by the prey. These results suggest that incorporating NTIs into dynamic models and ecological theory is necessary for a more complete understanding of the mechanisms of species coexistence and spatial variability. This knowledge is critical for understanding ecosystem responses to ongoing climate and global changes
Circulating Bilirubin Levels, but Not Their Genetic Determinants, Are Inversely Associated with Steatotic Liver Disease in Adolescents
No full textEpidemiologic studies suggest that elevated plasma unconjugated bilirubin confer protection against steatotic liver disease (SLD) in adults. However, evidence supporting this protective role in adolescents remains limited. We aimed to assess the association between serum bilirubin levels and their genetic determinants in protecting against SLD in Chilean adolescents. We conducted a cross-sectional study with 704 adolescents aged 15.4 ± 1 years (52% girls) of the Chilean Growth and Obesity Cohort Study. Ultrasonography echogenicity was used to diagnose SLD. We measured Z-scores of body mass index (z-BMI), total bilirubin (TB), and the genetic determinants of bilirubin (including rs887829 genotypes of UGT1A1 and bilirubin polygenic scores). Multiple logistic regression models evaluated the associations between standardized TB and its genetic determinants with SLD. We found that 1-SD of standardized plasma TB was significantly associated with a 30% reduction in the likelihood of SLD after adjustment by sex, age, z-BMI, and ethnicity (OR = 0.7; 95% CI = 0.50–0.96; p = 0.03). No significant associations were found among the rs887829 genotypes, bilirubin polygenic scores, and SLD in logistic regression models adjusted by covariates. Increased circulating bilirubin levels are unlikely causally associated with protection against SLD, and the cross-sectional association could be due to unmeasured confounding.Comisión Nacional de Investigación Científica y Tecnológica de Chile CONICYTISCIIIAgencia Nacional de Investigación y Desarrollo de Chile ANIDPontificia Universidad Católica de ChileERDFFONDECYTSpanish National Cancer Research Centr
El papel de la Inteligencia Artificial en la integración de la multiómica en cáncer de mama
No full textIn an era of precision oncology, genomic testing plays a crucial role in the management of breast cancer. A variety of complex techniques for germline, somatic, and gene expression testing are routinely used as part of our clinical practice. However, challenges remain in both interpreting genomic data and in the ever-expanding breadth of available tumor information. Artificial intelligence (AI), specifically machine learning and deep learning models, can create and facilitate the interpretation of complex genetic data, predict patient outcomes, and personalize treatment plans. Herein, we present a review of the current role of AI integrating multi-omics in BC.En la era de la medicina de precisión, las pruebas genómicas desempeñan un papel crucial en el tratamiento del cáncer de mama (CM). En la práctica clínica se utilizan de manera habitual una variedad de técnicas complejas tanto para línea germinal como somática y de expresión genética. Sin embargo, persisten desafíos en la interpretación de los datos genómicos dada su complejidad creciente. La inteligencia artificial (IA) y, específicamente, los modelos de aprendizaje automático y aprendizaje profundo, tienen la capacidad de crear y facilitar la interpretación de datos genéticos complejos, predecir los resultados de los pacientes y personalizar los planes de tratamiento. Aquí, presentamos una revisión del papel actual de la IA en la integración de multiómicas en CM
Contingent Agreements to Reduce the Impacts of Droughts on Human Water Consumption
No full textOne of the expected impacts of climate change is the alteration of precipitation and temperatures, modifying hydrological regimes and water availability. Faced with these changes, it is essential to adopt measures to guarantee the quantity, quality and continuity of drinking water supply to the population. This chapter proposes an instrument that consists of the design and implementation of pre-agreement contracts for the temporary transfer of water volumes from agriculture to water utilities. The application of the instrument is presented using the Aconcagua River basin and the Valparaíso-Viña del Mar conurbation in Chile as a case study. Through simulation models, the transfers, and economic compensations of a potential application of the instrument are characterized and evaluated considering different future climate scenarios, drought triggers for activation of pre-agreements, compensation scenarios based on human basic water consumption thresholds, and opportunity cost of water used in the agricultural sector
Identification of non-tuberculous mycobacteria in the domestic drinking water network in the Metropolitan Region of Chile
No full textTesis (Magíster en Investigación en Ciencias de la Salud)--Pontificia Universidad Católica de Chile, 2024Introducción: Micobacterias no tuberculosas (MNT) están ampliamente presentes en el medio ambiente y algunas especies son patógenos oportunistas. Existe una tendencia creciente en la incidencia de la enfermedad de MNT, especialmente en pacientes inmunocomprometidos. Objetivo: Identificar la presencia de micobacterias no tuberculosas en la red de agua potable de la Región Metropolitana de Chile. Métodos: Se recolectaron 110 muestras de agua potable doméstica provenientes de 33 comunas, se procesaron para búsqueda de MNT. Tras un protocolo de filtración y descontaminación, las muestras fueron cultivadas en medio Middlebrook 7H11. La identificación de especies fue realizada mediante MALDI-ToF y secuenciación de RNA 16S. Resultados: Un 30,9% (34/110) de las muestras de agua analizadas resultaron positivas para MNT, identificándose un total de 45 aislamientos. Mycobacterium del grupo mucogenicum fueron los más frecuentes con 51.1% (23/45), seguido por Mycobacterium frederiksbergense 15,6% (7/45) y Mycobacterium fluoranthenivorans 11,1% (5/45). También se identificaron MNT de potencial patógeno como M. chelonae (n=3) y M. fortuitum (n=1), M. kansasii (n=1). Conclusiones: Este estudio evidencia que el aislamiento de MNT es frecuente en agua potable de la Región Metropolitana. Algunas especies encontradas son raramente causales de enfermedad, pero es importante considerar la presencia MNT de potencial oportunista en huéspedes inmunocomprometido
Impact of Training Interventions on Physical Fitness in Children and Adolescent Handball Players: A Systematic Review and Meta-Analysis
No full textIntroduction: The developmental stage of handball training is critical for the enhancement of physical fitness. However, there is considerable methodological variability in the interventions implemented to improve performance in children and adolescents. Objective: This paper examines the characteristics and effectiveness of physical training interventions on fitness components in youth handball players through a systematic review and meta-analysis. The review identifies and classifies the types of strategies and training modalities used, while the meta-analysis quantifies their effects on physical performance. Methods: A systematic search was conducted in the databases Web of Science, Scopus, SPORTDiscus, PubMed, and MEDLINE, identifying 61 studies. Of these, fifty-three were included in the systematic review and eight met the criteria for the meta-analysis. The analysis focused on interventions targeting 787 participants aged 8 to 18 years (15.4 mean) and addressing various components of physical fitness. The methodological quality and risk of bias were assessed using the Cochrane Risk of Bias Tool. Results: The meta-analysis revealed significant and positive effects of the interventions on physical performance. Plyometric training was associated with improvements in peak power (SMD = 1.41; 95% CI: 0.91 to 1.91), sprint performance (SMD = −1.27; 95% CI: −1.93 to −0.62), and jump ability (SMD = 3.69; 95% CI: 3.21 to 4.17). Resistance band training also showed a positive impact on jump height (SMD = 1.56; 95% CI: 1.25 to 1.86) and agility (SMD = 0.42; 95% CI: 0.19 to 0.65). Heterogeneity ranged from low to moderate across outcomes. Conclusion: Plyometric and resistance band training interventions are effective strategies to enhance physical fitness in young handball players. These findings provide a scientific basis for designing evidence-based training programs aimed at comprehensive physical development during formative athletic stages
Workplace diversity in female-dominated industries and intraindividual identity conflict
No full textThis research paper examines the impact of gender and socioeconomic status (SES) diversity on intraindividual identity conflict within a female-dominated economic sector. The study also evaluates whether this relationship is moderated by gender and SES, as suggested in prior research. A quasi-experimental design was employed with 186 child protection workers as participants. Using vignettes that depicted varying levels of diversity, participants were randomly assigned to different conditions. The degree of dissimilarity was determined by comparing the diversity level described in the vignette with the participants’ individual characteristics, and intraindividual identity conflict was subsequently measured. Findings revealed that SES dissimilarity within a workgroup is associated with heightened intraindividual identity conflict. Furthermore, the study confirmed that SES moderates the relationship between diversity and intraindividual identity conflict. This research contributes to the existing body of knowledge on the effects of diversity on group identity conflicts, with a particular focus on intraindividual conflict in feminized occupations. Additionally, the findings on SES diversity underscore the importance of advancing our understanding of socioeconomic or class diversity and expanding the study of diversity beyond the Global North—topics that have been largely overlooked in the literature