Universidad de Magallanes
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Ancient dog mitogenomes support the dual dispersal of dogs and agriculture into South America
No full textArchaeological and palaeogenomic data show that dogs were the only domestic animals introduced during the early peopling of the Americas. Hunter-gatherer groups spread quickly towards the south of the continent, but it is unclear when dogs reached Central and South America. To address this issue, we generated and analysed 70 complete mitochondrial genomes from archaeological and modern dogs ranging from Central Mexico to Central Chile and Argentina, revealing the dynamics of dog populations. Our results demonstrate that pre-contact Central and South American dogs are all assigned to a specific clade that diverged after dogs entered North America. Specifically, the divergence time between North, Central and South American dog clades is consistent with the spread of agriculture and the adoption of maize in South America between 7000 and 5000 years ago. An isolation-by-distance best characterizes how dogs expanded into South America. We identify the arrival of new lineages of dogs in post-contact South America, likely of European origin, and their legacy in modern village dogs. Interestingly, the pre-contact Mesoamerican maternal origin of the Chihuahua has persisted in some modern individuals
Higher variability of bacterial communities across space than over time in Antarctic lakes, and contrasting assembly processes
No full textAs sentinels of environmental changes, Antarctic lakes are ideal systems for studying the temporal and spatial dynamics of microbial communities. However, the relative magnitude and underlying mechanisms driving these variations remain poorly understood. Studying the spatiotemporal variation of microbial communities is crucial to provide a robust baseline for predicting ecosystem responses to global changes. Here, we investigated the spatial and inter-annual variation of bacterial community structure and their underlying assembly processes across sediment and water habitats in 11 lakes on the Fildes Peninsula, Maritime Antarctica, sampled during austral summers from 2017 to 2023, using 16S rRNA gene sequencing. The communities primarily clustered by habitat, with higher diversity in sediment (characterized by Rhodoferax, Intraporangiaceae, and Vicinamibacterales) compared to water (characterized by Polaromonas, Flavovacterium, and Sporichthyaceae). Spatial turnover of communities dominated over inter-annual variation in both habitats. Accordingly, the temporal core microbiome showed greater stability than the spatial core. The conserved bacterial communities (core communities) over time and across space exhibited a strikingly similar taxonomic composition. Community assembly processes differed between habitats, with a stronger contribution of dispersal limitation in sediment, versus ecological drift in water, as expected from the differences in connectivity within each habitat. Spatial and temporal variations in sediment were driven by globally similar assembly processes. In contrast, in water communities, different assembly processes explained the spatial and temporal variation. These insights emphasize the need to consider both spatial and temporal scales and various habitat types when predicting future bacterial dynamics in Antarctic lakes in a changing environment.IMPORTANCEUnderstanding the inherent baseline microbial dynamics in Antarctic lakes is crucial for predicting their responses to environmental changes. Our findings underscore the predominance of spatial (rather than inter-annual) factors in shaping bacterial communities and highlight the slightly higher contribution of stochastic processes in sediment compared to water habitats. The stochastic processes differed considerably among habitats. The greater stability of the temporal core microbiome suggests a certain degree of resilience toward possible seasonal fluctuations between the inter-annual sampling dates. In water, dispersal limitation and homogeneous selection played a greater role in the spatial than in the temporal turnover of communities, whereas environmental filtering exerted a stronger influence over time. Future studies should integrate both spatial and temporal dimensions in evaluating microbial community variability to improve forecasting of ecosystem shifts in response to global change and thus provide a better baseline for Antarctic biodiversity conservation and management
Percepción docente sobre la implementación en modalidad B-learning del enfoque de indagación en la enseñanza de las ciencias: perspectivas desde Magallanes-Chile
No full textStrengthening science education processes is of utmost importance in order to address the emerging challenges of today's society. That said, the Chilean Ministry of Education has been promoting the Scientific Inquiry Program for Science Education (ICEC), which has been led by various universities in the country, including the University of Magallanes. In this context, the present study was conducted. It sought to explore the perceptions of teachers from the Magallanes region who participated in the ICEC program and to determine whether they experienced changes in their understanding and practice of science teaching.
The research was conducted through semi-structured interviews and a qualitative phenomenographic approach. Teachers' experiences and assessments of the implementation of the inquiry approach in school settings were collected. Overall, the results suggest that, for most participants, the program represented a significant training opportunity, associated with increased confidence in science teaching, the incorporation of new methodological strategies, and increased motivation to disseminate the approach among their colleagues. Similarly, positive perceptions of the program's contributions were identified, along with challenges primarily linked to the institutional conditions for implementing the inquiry approach in educational institutions.
eption of ICEC and the effect it had on professional practice. The results show that for them it was a significant contribution in that they positively changed their perception of science teaching, promoted the program among teachers, and applied the acquired tools, with significant improvements in their pedagogical practices
Climate's firm grip on glacier ablation in the Cordillera Darwin Icefield, Tierra del Fuego
No full textThe Cordillera Darwin Icefield (CDI) in Tierra del Fuego is one of the largest temperate ice bodies in the Southern Hemisphere. We simulate the climatic energy and mass balance of its glaciers (2000-2023), which are sensitive indicators of climatic changes in the Southern Hemisphere's higher mid-latitudes. Year-round westerly winds cause strong climatic gradients across the mountain range, reflected in the energy and mass fluxes. Our results reveal a significant increase in surface melt (+0.18 m w.e. yr-1 per decade) over the past two decades. We also present the first estimate of dynamically controlled mass loss into adjacent fjords and lakes by frontal ablation, amounting to 1.44 +/- 0.94 Gt yr-1 (26 % of the total CDI mass loss). Frontal losses are mainly channelized through few marine-terminating glaciers. While frontal ablation is important for predicting the fate of individual glaciers, for the CDI as a whole, atmospheric conditions exert the main control on the current glacier evolution
Lamb Production in Patagonia
No full textThe lamb production area in Chilean Patagonia are located to the east in the Andean rain shadow, on the continental part and Tierra del Fuego Island, occuping an area of 35,962.6 km[[sup]]2[[/sup]]. The lamb meet is a relevant market today in this region, but is important to improve the grassland and rangeland degradation to maintain the quality of this product for the future. For latter, to improve the lamb production, grazing managemnet is the key factor where the calculate of carryng capacity is the primary determiantion to sustainable farm production. But also another points are important, to underpin the description of lamb systems, different characteristics are detailed in this chapter; as the geographical area, weather, rangelands soils, Magellan grazing ecosystem, lambs production, health and diseases, lamb and wildlife coexistence, welfare and market perspectives
Comparative thermal tolerance of haploid and diploid phases of two intertidal Antarctic red algae Iridaea cordata and Sarcopeltis antarctica
No full textPhysiological and biochemical responses to elevated temperatures were studied in the isomorphic tetrasporophyte (diploid) and gametophyte (haploid) phases of two Antarctic red macroalgal species (Sarcopeltis antarctica, former Gigartina skottsbergii-and Iridaea cordata), assessing whether ploidy affects the responses to extreme and fast warming events. The tetrasporophyte and gametophyte fronds of both species were exposed in the laboratory to 2 degrees C (control) and 8 degrees C (warming event) for up to 3 days. Photosynthetic performance and concentrations of chlorophyll a, total carotenoids, and mycosporine-like amino acids (MAAs) were determined. Inter-and intraspecific differences in physiological and biochemical responses to temperature were observed. Temperature increases slightly stimulated photosynthetic activity (Fv/Fm) over 15 % at 8 degrees C only in gametophytes of both species. Intraspecific variation in the content of MAAs and total carotenoids was also observed, with tetrasporophytes of S. antarctica and gametophytes of I. cordata evidencing a significative 60 % MAA content decrease (accompanied by a slight increase in total carotenoid) at 8 degrees C. These results highlight the role of carotenoids in the acclimation to elevated temperature and MAA content at the lowest ones. Although some intraspecific differences in the responses of haplo-diplontic life cycle phase were observed, there were low effects of exposure to 8 degrees C on photochemistry, outlining the physiological tolerance of both ploidy phases of intertidal species to extreme pulses of temperature increases in Antarctica
Spatial variability of soil, water, and vegetation in a Patagonian wetland: Implications for sustainable land management planning
No full textSite-specific management (SSM) is a key strategy for optimizing inputs in agriculture and livestock production by accounting for the spatial variability of ecosystem properties. Due to the ongoing degradation of Patagonian Vegas (wetland meadows), SSM may provide a framework for sustainable livestock and agricultural management in these ecosystems. This study aimed to assess spatial variability and relationships between soil properties, water dynamics, and vegetation distribution in a Patagonian Vega and to classify and group soil and ecosystem properties into distinct management zones, providing a functional framework for land-use planning and conservation. A grid-based sampling approach was used to assess soil, water, and plant biodiversity across seven topographic zones: northern summit, northern high and low footslopes, center of the Vega, southern low and high footslopes, and southern summit. Five key soil variables-bulk density (BD), aluminum pyrophosphate (Alp), soil organic carbon (SOC), cation exchange capacity (CEC), and the coefficient of linear extensibility (COLE)-were analyzed using geostatistics, along with soil moisture (M), water table height (WT), soil classification, and plant biodiversity. The results revealed strong spatial dependence of soil and water variables, differentiating three to five zones depending on the indicator used. While wetter, organic-rich areas may support higher productivity and grazing, they are also more vulnerable to degradation considering that the higher soil moisture decreases the mechanical stability of the soil. Conversely, drier, shallower soils may require conservation-focused management. These findings provide a foundation for future land-use planning, though further studies are needed to experimentally assess the long-term effects of different management strategies on soil stability and ecosystem resilience
Strengthening Environmental Conservation: The Role of Connectedness to Nature and Place Attachment in Intentions to Protect Urban Wetlands in Punta Arenas, Chilean Patagonia
No full textThis study investigates the psychological factors influencing intentions to protect urban wetlands in Punta Arenas, Chile. It examines residents' perceptions and valuations of urban wetlands, exploring relationships between wetland-specific variables and broader environmental and place-based factors. A theoretical model is tested, incorporating place attachment, connectedness with nature, and previous pro-environmental behaviors. The study utilizes a survey with 297 participants and employs structural equation modeling to analyze the data. The results reveal a complex interplay between place-based identities, general environmental orientations, and wetland-specific cognitions in shaping conservation intentions. Connectedness to nature emerges as a central factor influencing both attitudinal and behavioral intention pathways toward wetland protection. The study's findings have implications for targeted interventions and policy decisions aimed at promoting wetland conservation in urban areas
The High Sensitivity of Sensory Processing and its relationship with postural balance in older people La Alta Sensibilidad del Procesamiento Sensorial y su relación con el equilibrio postural en personas mayores
No full textEl rasgo de alta sensibilidad al procesamiento sensorial (HSPST) es una característica neurológica específica que afecta al 20% de la población mundial. Se caracteriza porque la Persona Altamente Sensible (PAS) tiene altos niveles de capacidad empática, relatividad emocional y sensibilidad ante estímulos sutiles imperceptibles para los demás. Objetivo: Relacionar el rasgo del HSPST y el equilibrio postural en personas mayores. Métodos: El estudio fue de tipo correlacional. Se realizó en una única etapa mediante cuestionario presencial y evaluación del equilibrio postural. Los participantes en este estudio fueron seleccionados mediante muestreo accidental y no aleatorio de la ciudad de Punta Arenas, Chile. La muestra estuvo compuesta por 77 adultos mayores con edades entre 63 y 77 años. Resultados: La puntuación de la Escala de personas de alta sensibilidad (HSPS) predijo significativamente el resultado del equilibrio postural con los ojos cerrados (EC). El estudio demostró una correlación entre la puntuación HSPS y el equilibrio postural. Si bien se incrementó la puntuación HSPS, se esperaba un equilibrio postural en los adultos mayores. Conclusiones: las personas con un puntaje HSPS alto se establecería como predictor del resultado del equilibrio con EC, observándose que por cada aumento de una unidad en el puntaje HSPS, hay una disminución del 6% en la probabilidad de tener el equilibrio alterado. Palabras clave: Procesamiento sensorial, Equilibrio postural, Envejecimiento, Sensibilidad, Neurociencias. Abstract. High sensory processing sensitivity trait (HSPST) is a specific neurological characteristic affecting 20% of the world's population. It is characterized because the Highly Sensitive Person (HSP) has high levels of empathic capacity, emotional relativity, and sensitivity to subtle stimuli imperceptible to others. Objective: Relate the trait of the HSPST and postural balance in older people. Methods: This was a correlational. It was conducted in a single stage using a presential questionnaire and postural balance assessment. The participants in this study were selected by non-random, accidental sampling from the city of Punta Arenas, Chile. The sample comprised 77 older adults aged between 63 and 77 years. Results: The High Sensitive Person Scale (HSPS) score significantly predicted the eye-closed (EC) postural balance outcome. The study demonstrated a correlation between the HSPS score and postural balance. While increasing the HSPS score, postural balance was expected in older adults. Conclusions: People with a high HSPS score would be established as a predictor of the result of balance with EC, observing that for every one unit increase in the HSPS score, there is a 6% decrease in the probability of having a balance altered. Keywords: Sensory processing, Postural balance, Aging, Sensitivity, Neurosciences
Wnt-5a/Ca2+pathway modulates endogenous current and oocyte structure of Xenopus laevis
No full textWnt signaling plays an essential role in cellular processes like development, maturation, and function maintenance. Xenopus laevis oocytes are a suitable model to study not only the development but also the function of different receptors expressed in their membranes, like those receptors expressed in the central nervous system (CNS) including Frizzled 7. Here, using frog oocytes and recordings of endogenous membrane currents in a two- electrode path configuration along with morphological observations, we evaluated the role of the non-canonical Wnt-5a ligand in oocytes. We found that acute application of Wnt-5a generated changes in endogenous calcium- dependent currents, entry oscillatory current, the membrane's outward current, and induced membrane depolarization. The incubation of oocytes with Wnt-5a caused a reduction of the membrane potential, potassium outward current, and protected the ATP current in the epithelium/theca removed (ETR) model. The oocytes exposed to Wnt-5a showed increased viability and an increase in the percentage of the germinal vesicle breakdown (GVBD), at a higher level than the control with progesterone. Altogether, our results suggest that Wnt-5a modulates different aspects of oocyte structure and generates calcium-dependent endogenous current alteration and GVDB process with a change in membrane potential at different concentrations and times of the exposition. These results help to understand the cellular effect of Wnt-5a and present the use of Xenopus oocytes to explore the mechanism that could impact the activation of Wnt signaling