Universidad de Magallanes
Not a member yet
1947 research outputs found
Sort by
Ecological variation in invasive brown trout (Salmo trutta) within a remote coastal river catchment in northern Patagonia complicates estimates of invasion impact
No full textSalmonids were first introduced into the Chilean fresh waters in the 1880s, and c. 140 years later, they are ubiquitous across Chilean rivers, especially in the southern pristine fresh waters. This study examined the brown trout (Salmo trutta) and native taxa ecology in two adjacent but contrasting rivers of Chilean Patagonia. During spring 2016 and spring-fall 2017 we examined the variation in benthic macroinvertebrate and fish community composition and characterized fish size structure, stomach contents, and stable isotopes (delta 13C and delta 15N) to understand population structure, fish diet, and trophic interactions between S. trutta and native taxa. The native Galaxias maculatus (puye) dominated the fish community (74% of abundance). S. trutta was less abundant (16% of survey catch) but dominated the fish community (over 53%) in terms of biomass. S. trutta showed distinct diets (stomach content analysis) in the two rivers, and individuals from the larger river were notably more piscivorous, consuming native fish with a relatively small body size (<100-mm total length). Native fishes were isotopically distinct from S. trutta, which showed a wider isotopic niche in the smaller river, indicating that their trophic role was more variable than in the larger river (piscivorous). This study provides data from the unstudied pristine coastal rivers in Patagonia and reveals that interactions between native and introduced species can vary at very local spatial scales
Volverse árbol, reconstruir la memoria: redes bioculturales en los bosques de pewen (Araucaria araucana) del sur de los Andes
No full textRelationships between people and trees are continually unfolding in the contexts of situated social-ecological systems. In current studies on social-ecological systems linked with trees, we commonly find two approaches: the first focuses on 'biological entities', examining the ecological dynamics of tree species and associated biodiversity. The second approach focuses on people, analyzing 'human agency' along with historical and contemporary political or other forces shaping human-tree relationships. In this paper, we explore social-ecological systems associated with the Pewen (Araucaria araucana), one of the most iconic and sacred trees from the southern Andes. We first describe some of our own research findings on Pewen for both approaches described above. We then develop a third perspective, that we call 'relational', which highlights biocultural relations and has the potential to overcome both the 'ecological/social' and the 'biological entity/human agency' dichotomies. Our relational approach allows a closer enquiry on how actors (e.g. trees and their seeds, wildlife, and people, among others) interact in complex and sympoietic biocultural networks, recognizing the biocultural memory of the system that emerges as an on-going complex of dynamics relations that must be enacted and performed on a daily basis. Furthermore, it stresses that people-pewen networks are continuously built and rebuilt in open systems subjected to historical and contemporary drivers of change
El parto por cesárea en Chile y la Región de Magallanes y Antártica Chilena. Reflexiones basadas en la evidencia internacional.
No full textIntroducción: En las últimas décadas en Chile se observa un aumento de la incidencia del parto por cesárea, por sobre la tasa recomendada por la Organización Mundial de la Salud OMS). A nivel Latinoamericano Chile posee una de las tasas de cesáreas más alta y a nivel nacional la Región de Magallanes y Antártica Chilena muestra similar comportamiento. Metodología: Se realizó una revisión de la literatura científica en bases de datos indexadas, se recopiló evidencia para el análisis de algunos factores que podrían explicar dicha prevalencia en el país y en la región más austral de Chile. Se analizaron los egresos hospitalarios de Chile y la región en el período 2015 a 2018, se calculó y luego comparó la tasa de partos por cesárea para ambas poblaciones. Resultados: En el período en estudio la tasa promedio nacional de cesáreas fue 49,6% y en Región de Magallanes cercana al 63%, en esta región la tasa de parto por cesárea prácticamente duplica al parto espontáneo en todo el período en estudio. Discusión: Ambas tasas son alarmantes y están muy lejos de la recomendación de la OMS y no existe suficiente evidencia que explique las causas que han llevado a estos resultados
ANÁLISIS DE LAS CAUSALES DE DESERCIÓN ACADÉMICA EN UNA UNIVERSIDAD ESTATAL CHILENA
No full textObjetivo: El objetivo central de este estudio fue identificar las causales de deserción de los alumnos de primer año, para la cohorte del periodo 2013-2018, en la Universidad de Magallanes, Punta Arenas, Chile. Marco Teórico: Para este tema, la mayoría de los autores se sustentan en la Teoría de Retención de Vicent Tinto, que explica el proceso de permanencia en la educación superior como una función del grado de ajuste entre el estudiante y la institución, adquirido a partir de las experiencias académicas y sociales, concepto de integración académica y social en la comunidad universitaria. Método: Esta investigación es de carácter exploratoria, descriptiva, longitudinal y cuantitativa. Es descriptiva debido a que es observacional y se estructura a través de un diseño no experimental, de tipo transaccional descriptivo y es longitudinal porque se realiza un seguimiento durante un período de tiempo. Resultados y Discusión: Los datos muestran que el factor académico es el principal motivo de deserción, seguido por el académico-financiero, luego se ubica el motivo otros y finalmente el factor financiero, cuyo lugar se explica por la vulnerabilidad económica de los alumnos, que en su mayoría tienen acceso a gratuidad educativa (subsidio estatal a la matrícula). Implicaciones de la investigación: Los resultados permitirían a la Universidad, aplicar programas para evitar la deserción, buscando soluciones para el factor académico, vía planes remediales. Originalidad/Valor: Este estudio permite visualizar, en forma exploratoria los motivos principales que afectan la deserción universitaria en una institución estatal ubicada en una zona extrema de Chile (Patagonia Austral
Drivers of plant diversity, community composition, functional traits, and soil processes along an alpine gradient in the central Chilean Andes
No full textHigh alpine regions are threatened but understudied ecosystems that harbor diverse endemic species, making them an important biome for testing the role of environmental factors in driving functional trait-mediated community assembly processes. We tested the hypothesis that plant community assembly along a climatic and elevation gradient is influenced by shifts in habitat suitability, which drive plant functional, phylogenetic, and spectral diversity. In a high mountain system (2400-3500 m) Region Metropolitana in the central Chilean Andes (33 degrees S, 70 degrees W). We surveyed vegetation and spectroscopic reflectance (400-2400 nm) to quantify taxonomic, phylogenetic, functional, and spectral diversity at five sites from 2400 to 3500 m elevation. We characterized soil attributes and processes by measuring water content, carbon and nitrogen, and net nitrogen mineralization rates. At high elevation, colder temperatures reduced available soil nitrogen, while at warmer, lower elevations, soil moisture was lower. Metrics of taxonomic, functional, and spectral alpha diversity peaked at mid-elevations, while phylogenetic species richness was highest at low elevation. Leaf nitrogen increased with elevation at the community level and within individual species, consistent with global patterns of increasing leaf nitrogen with colder temperatures. The increase in leaf nitrogen, coupled with shifts in taxonomic and functional diversity associated with turnover in lineages, indicate that the ability to acquire and retain nitrogen in colder temperatures may be important in plant community assembly in this range. Such environmental filters have important implications for forecasting shifts in alpine plant communities under a warming climate. We tested the hypothesis that plant-soil feedbacks along a climatic and elevation gradient influence plant community assembly through shifts in habitat suitability, which drive plant functional, phylogenetic, and spectral diversity in a high mountain system (2400-3500 m) of Region Metropolitana in the Chilean Andes (33 degrees S, 70 degrees W). We found that leaf nitrogen increased with increasing elevation, and taxonomic and functional diversity associated with turnover in lineages peaked at mid-elevations, indicating that the ability to acquire and retain nitrogen in colder temperatures may be important in plant community assembly in this range. Such environmental filters have important implications for forecasting shifts in alpine plant communities under a warming climate.imag
Catalyzing Holistic Conservation-Based Development Through Ethical Travel Experiences Rooted in the Bioculture of Patagonia's Subantarctic Natural Laboratories
No full textAbstract Synchronous losses of biological, linguistic, and cultural diversity are contributing to processes of biocultural homogenization , a persistent downgrading in how people perceive biodiversity, environmental, and cultural conditions, and what they consider as normal. Some have linked biocultural homogenization with neoliberal practices that emphasize standardization and efficiencies in order to enhance capital accumulation. In Chile, which is highly centralized, urban, and centered around neoliberal development, biocultural homogenization is especially concerning, as it may lower support for conservation. Thus, when thinking about conservation-based development in Patagonia, locally driven initiatives that foster biocultural reawakening, democratize science, and catalyze sustainable development, might help address biocultural homogenization and build conservation support. This mixed-methods, intrinsic case study explored three initiatives underway in the Aysén and Magallanes regions of Chile that address some of these outcomes: (1) Subantarctic Natural Laboratories; (2) 3-Hs Biocultural Ethic and FEP Cycle Approach; and (3) Scientific Tourism Collaborative Learning Networks. We sought to better understand their methods and implementations and explore how their integration might strengthen conservation-based development in Patagonia, through ethical travel experiences rooted in the bioculture of local communities. Results suggest promise for a combined approach; thus, additional research and consideration are merited
A 7-Week Summer Camp in Antarctica Induces Fluctuations on Human Oral Microbiome, Pro-Inflammatory Markers and Metabolic Hormones Profile
No full textAntarctic camps pose psychophysiological challenges related to isolated, confined, and extreme (ICE) conditions, including meals composed of sealed food. ICE conditions can influence the microbiome and inflammatory responses. Seven expeditioners took part in a 7-week Antarctic summer camp (Nelson Island) and were evaluated at Pre-Camp (i.e., at the beginning of the ship travel), Camp-Initial (i.e., 4th and 5th day in camp), Camp-Middle (i.e., 19th-20th, and 33rd-34th days), Camp-Final (i.e., 45th-46th day), and at the Post-Camp (on the ship). At the Pre-Camp, Camp-Initial, and Camp-Final, we assessed microbiome and inflammatory markers. Catecholamines were accessed Pre- and Post-Camp. Heart rate variability (HRV), leptin, thyroid stimulating hormone (TSH), and thyroxine (T4) were accessed at all time points. Students' t-tests or repeated-measures analysis of variance (one or two-way ANOVA) followed by Student-Newman-Keuls (post hoc) were used for parametric analysis. Kruskal-Wallis test was applied for non-parametric analysis. Microbiome analysis showed a predominance of Pseudomonadota (34.01%), Bacillota (29.82%), and Bacteroidota (18.54%), followed by Actinomycetota (5.85%), and Fusobacteria (5.74%). Staying in a long-term Antarctic camp resulted in microbiome fluctuations with a reduction in Pseudomonadota-a "microbial signature" of disease. However, the pro-inflammatory marker leptin and IL-8 tended to increase, and the angiogenic factor VEGF was reduced during camp. These results suggest that distinct Antarctic natural environments and behavioral factors modulate oral microbiome and inflammation
Exploring Machine Learning Algorithms and Protein Language Models Strategies to Develop Enzyme Classification Systems
No full textDiscovering functionalities for unknown enzymes has been one of the most common bioinformatics tasks. Functional annotation methods based on phylogenetic properties have been the gold standard in every genome annotation process. However, these methods only succeed if the minimum requirements for expressing similarity or homology are met. Alternatively, machine learning and deep learning methods have proven helpful in this problem, developing functional classification systems in various bioinformatics tasks. Nevertheless, there needs to be a clear strategy for elaborating predictive models and how amino acid sequences should be represented. In this work, we address the problem of functional classification of enzyme sequences (EC number) via machine learning methods, exploring various alternatives for training predictive models and numerical representation methods. The results show that the best performances are achieved by applying representations based on pre-trained models. However, there needs to be a clear strategy to train models. Therefore, when exploring several alternatives, it is observed that the methods based on CNN architectures proposed in this work present a more outstanding facility for learning and pattern extraction in complex systems, achieving performances above 97% and with error rates lower than 0.05 of binary cross entropy. Finally, we discuss the strategies explored and analyze future work to develop integrated methods for functional classification and the discovery of new enzymes to support current bioinformatics tools
Influence of Rangeland Land Cover on Infiltration Rates, Field-Saturated Hydraulic Conductivity, and Soil Water Repellency in Southern Patagonia
No full textThis study investigated the influence of rangeland land cover on infiltration rates (IRs), field-saturated hydraulic conductivity (Kfs), and soil water repellency in Patagonia. Four land cover types (shrubs, dwarf heath shrubs, bare soil, and Inter tussock) were examined to assess their effects on hydrological pro-cesses. IR was measured using the single-ring method, and soil water repellency was evaluated using the Beerkan method. We hypothesized that land cover type affects IR, Kfs, and soil water repellency. The results showed significant variations in IRs among land covers, with Tsf displaying lower rates than the other covers. Soil water repellency was prevalent in shrub and dwarf heath shrub -covered soils. Lateral flow was observed, indicating limited water infiltration. The obtained Kfs values were higher than the calculated hydraulic conductivity values (Ks). However, further investigation is required to assess the im-pact of capillarity (i.e.,α*) on Kfs determination. This study enhances our understanding of hydrological processes in rangeland ecosystems and provides valuable insight into land management practices. By elu-cidating the relationships among land cover, IR, Kfs, and soil water repellency, this study contributes to sustainable water resource management in arid and semiarid regions.© 2023 The Authors. Published by Elsevier Inc. on behalf of The Society for Range Management. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/
Scientists warning on the ecological effects of radioactive leaks on ecosystems
No full textA nuclear leakage or tactical nuclear weapon use in a limited war could cause immense and long-lasting ecological consequences beyond the direct site of exposure. We call upon all scientists to communicate the importance of the environmental impacts of such an event to all life forms on Earth, including humankind. Changes to ecosystem structure and functioning and species extinctions would alter the biosphere for an unknown time frame. Radiation could trigger cascade effects in marine, atmospheric and terrestrial ecosystems of a magnitude far beyond human capabilities for mitigation or adaptation. Even a "tactical nuclear war" could alter planet Earth's living boundaries, ending the current Anthropocene era