Universidad de Magallanes
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Local occurrences in San Felipe port: Daily life at Fuerte Bulnes (1844-1845) narrated by Santiago Dunne
No full textLivestock as a source of greenhouse gas emission
No full textIn this chapter, we will focus on describing enteric methane (CH4) as an energy loss and its role as a greenhouse gas (GHG), used strategies to reduce enteric CH4 in ruminants, and the most current techniques used to quantify enteric CH4 emissions in ruminants. The importance of studying animal bioenergetics to explains its apparent fragmentation and dissociation along its pathway in cattle. Cattle maintain a close symbiosis with their rumen microbiota, which provide them with the necessary energy resulting from the fermentation of the food they ingest. However, this process is not 100% efficient. Enteric CH4 is an energy loss and a GHG that contributes to global warming. Likewise, it is described how the manipulation of ruminal fermentation is one of the main CH4 mitigation strategies. Currently, the use of additives rich in secondary metabolites, such as tannins, saponins, flavonoids, and essential oils (EOs), among others, has been studied. Finally, techniques currently used to measure enteric CH4 emissions include sulfur hexafluoride (SF6) and an automated head camera system (GreenFeed) that can monitor CH4 and carbon dioxide (CO2) mass fluxes from ruminant respiration and burping
Renewable Source-Based Water Pumping Electrification in Mines: Current technologies and future trends
No full textWater pumping is an essential function in diverse industrial sectors, including manufacturing, mining, agriculture, oil and gas, and chemical processing. The global energy consumption of pumps is approximately 15%, and in the particular case of the mining industry, pumps can represent up to a 24% of the average consumption of energy, as shown in Figure 1. The use of water in the mining industry has some distinctive features compared to other industrial applications. Most of the large mines are located in arid or semiarid regions where water is scarce and there are few competing users, such as agriculture and towns. A mine itself could be the largest water user in the sector. Therefore, to cope with water scarcity, it could be necessary to transport the water large distances to supply a mine. In general, a mine requires water in several processes, some of them critical, then, pumping is crucial to ensure the continuous operation of the industry. On the other hand, regarding the geographical location, as mines could operate in windy regions and/or regions rich in solar irradiation, e.g., copper mines in Chile and Australia, or chromite mines in South Africa, the use of renewable energies to supply pumps is an attractive option. In this article, we explore pumping requirements in the mining industry, its possibilities for electrification based on renewables sources, the limitations, and the prospections of this relevant industrial sector
Women with disabilities and the loss of custody of their children: "Carers, but not mothers"
No full textHistorically, the motherhood of women with disabilities has been questioned due to negative representations surrounding it. It is assumed that women with disabilities cannot be mothers and, when they are, their capacity to care for their children is called into doubt. According to international literature, women with disabilities are more susceptible to losing the custody of their children. However, in Chile, there is scant evidence about this.Using the paradigm of situated feminist epistemologies, this paper analyzes the experiences of three Chilean mothers with disabilities who have faced judicial processes regarding their children's custody. Three dimensions emerged from the thematic analysis: (a) The role of carers under tension: "Carers, but not mothers!"; (b) The absence of support and reasonable accommodations: The institutional debt; and (c) The influence of ableism on custody processes. The findings reveal a series of adversities that women with disabilities must overcome to demonstrate their fitness as mothers. Institutional ableism hampers due process in cases about the custody of their children. As long as appropriate support is provided and the disabling view is transformed, mothers with disabilities can provide the care and parenting their children require
Associations among MHC genes, latitude, and avian malaria infections in the rufous-collared sparrow (Zonotrichia capensis)
No full textThe major histocompatibility complex (MHC) is a genetic region in jawed vertebrates that contains key genes involved in the immune response. Associations between the MHC and avian malaria infections in wild birds have been observed and mainly explored in the Northern Hemisphere, while a general lack of information remains in the Southern Hemisphere. Here, we investigated the associations between the MHC genes and infections with Plasmodium and Haemoproteus blood parasites along a latitudinal gradient in South America. We sampled 93 rufous-collared sparrows (Zonotrichia capensis) individuals from four countries, Colombia, Ecuador, Peru, and Chile, and estimated MHC-I and MHC-II allele diversity. We detected between 1-4 (MHC-I) and 1-6 (MHC-II) amino acidic alleles per individual, with signs of positive selection. We obtained generalized additive mixed models to explore the associations between MHC-I and MHC-II diversity and latitude. We also explored the relationship between infection status and latitude/biome. We found a non-linear association between the MHC-II amino acidic allele diversity and latitude. Individuals from north Chile presented a lower MHC genetic diversity than those from other locations. We also found an association between deserts and xeric shrublands and a lower prevalence of Haemoproteus parasites. Our results support a lower MHC genetic in arid or semi-arid habitats in the region with the lower prevalence of Haemoproteus parasites
Effects of Modified Voisin Rational Grazing in grasslands, Magallanes region and chilean Antarctic
No full textRESUMEN: Este estudio tiene como objetivo evaluar el efecto de un sistema de Pastoreo Racional Voisin Modificado en la ganadería ovina. Diferentes estudios han demostrado que la implementación del pastoreo Voisin incrementa la producción de pastos y carga animal, sin la necesidad de utilizar fertilizantes químicos, reduciendo costos de producción y dependencia de insumos agroindustriales. Se buscó comparar el Pastoreo Continuo con ajuste de carga con el Pastoreo Racional Voisin Modificado sobre la composición, estructura y diversidad biológica de las especies vegetales en dos formaciones típicas de la estepa magallánica (vega y mata-coirón), utilizando el método Whittaker modificado. Se evaluaron los factores biológicos que afectan la distribución de las especies entre los diferentes tratamientos. Finalmente se estimó el forraje disponible del Pastoreo Racional Voisin Modificado y del Pastoreo Continuo en vega y mata-coirón utilizando la metodología nueve pasos. Los resultados indican que el Pastoreo Racional Voisin Modificado no logró promover una variación significativa en la diversidad y riqueza de especies. Por el contrario, se registró una disminución de la cobertura vegetal en las formaciones mata-coirón y vegas. Esto provoca un aumento del porcentaje del suelo desnudo, obteniendo una disminución de la disponibilidad de forraje, lo cual se ve reflejado en vegas. Por otra parte, el PC tuvo un incremento relevante en la disponibilidad de forraje para la formación mata-coirón; en cuanto a la cobertura vegetal y porcentajes de suelo desnudo, éstos también disminuyen con el paso del tiempo para ambas formaciones vegetales evaluadas, siendo menor la disminución en mata-coirón
Mapping the Future: Revealing Habitat Preferences and Patterns of the Endangered Chilean Dolphin in Seno Skyring, Patagonia
No full textSimple Summary Models of species distribution allow us to learn how different environmental factors determine where species are found. Our study focused on the Chilean dolphin in Seno Skyring, Chilean Patagonia. We used three different methods to predict where these dolphins are likely to be found, based on environmental data like water temperature, salinity, and proximity to the coast, as well as human activities like fish farming. We found that dolphins are most commonly found within six kilometers of the coast, in areas with many fish farms. This suggests that the dolphins may be attracted to areas near fish farms. Understanding these patterns is crucial for developing strategies to protect the endangered Chilean dolphin, especially given the large fish-farming industry in Chile. Our research highlights the need for more knowledge and comprehensive conservation efforts to ensure the dolphins' long-term survival.Abstract Species distribution modeling helps understand how environmental factors influence species distribution, creating profiles to predict presence in unexplored areas and assess ecological impacts. This study examined the habitat use and population ecology of the Chilean dolphin in Seno Skyring, Chilean Patagonia. We used three models-random forest (RF), generalized linear model (GLM), and artificial neural network (ANN)-to predict dolphin distribution based on environmental and biotic data like water temperature, salinity, and fish farm density. Our research has determined that the RF model is the most precise tool for predicting the habitat preferences of Chilean dolphins. The results indicate that these dolphins are primarily located within six kilometers of the coast, strongly correlating with areas featuring numerous fish farms, sheltered waters close to the shore with river inputs, and shallow productive zones. This suggests a potential association between dolphin presence and fish-farming activities. These findings can guide targeted conservation measures, such as regulating fish-farming practices and protecting vital coastal areas to improve the survival prospects of the Chilean dolphin. Given the extensive fish-farming industry in Chile, this research highlights the need for greater knowledge and comprehensive conservation efforts to ensure the species' long-term survival. By understanding and mitigating the impacts of fish farming and other human activities, we can better protect the habitat and well-being of Chilean dolphins
Occurrence, residency, and habitat characterization of leopard seals in Chile
No full textLeopard seals have traditionally been considered Antarctic predators with a Southern Ocean distribution. Historically, sightings north of the Antarctic Polar Front were considered extralimital. However, recent studies suggest a significant presence of leopard seals in subantarctic regions. Here, we assess the spatial occurrence, residency status, and temporal trends of leopard seals in Chile using historical records, stranding reports, standardized monitoring data, photo-identification (photo ID) catalogs, and sightings from four research expeditions. We also characterize glaciers where sightings are concentrated, identifying glaciological and geomorphic attributes that prolong iceberg residency time, which is linked to high leopard seal concentrations. Based on these attributes, we evaluated other potential suitable glacial habitats in Patagonia. We obtained 438 sighting records of leopard seals from 1927 to 2023. Over the last 15 years, we documented a 4-18% annual increase in stranding events reported to national authorities. Most sightings (75%) were concentrated in two hotspots: National Park San Rafael Lagoon, located in Northern Patagonia, and Parry Fjord in Tierra del Fuego. Using photo ID catalogs, we identified 19 resident leopard seals, including 16 multi-year residents observed between 2010-2023 (10 in San Rafael, 6 in Tierra del Fuego) and 3 potential residents (observed multiple months in the same year in Tierra del Fuego). San Rafael monitoring data showed no inter-annual trend, but seasonal trends were observed. We also provide evidence of breeding in Chile, with records of at least 14 pups born and at least two females giving birth in multiple years. Our habitat characterization suggests that calving flux, fjord sinuosity, and fjord width variation are crucial for prolonging iceberg residency in hotspot areas. Based on these attributes, we identified 13 additional fjords in Patagonia as "very likely" suitable for leopard seals. Our study confirms that Patagonia is part of the species' breeding distribution, shifting the paradigm that leopard seals are merely visitors north of the Antarctic Polar Front. Given the limited number of suitable glaciers in Chile and the potential impacts of climate change, our assessment highlights glacial retreat as a major threat for the ecosystem of this pagophilic marine apex predator in South America
Relationship between Perceived Stress, Physical Performance, and Balance in Older Adults: An Exploratory Study Relación entre el estrés percibido, desempeño físico y equilibrio de personas mayores. Un estudio exploratorio
No full textEste estudio examinó la relación entre el estrés percibido, el rendimiento físico y el equilibrio en adultos mayores de Punta Arenas, Chile. Se evaluaron 40 participantes y se encontró que el 57,5% experimentaba estrés ocasional y el 10% estrés frecuente. Aunque se observó un aumento en el índice vestibular en algunos participantes, no se encontraron correlaciones significativas entre el estrés, el rendimiento físico y el equilibrio. Estos hallazgos sugieren que el estrés percibido no está directamente relacionado con el rendimiento físico o el equilibrio en adultos mayores. Palabras clave: Envejecimiento, Estrés Percibido, Estabilidad Postural. Abstract. This study explored the relationship between perceived stress, physical performance, and balance in older adults from Punta Arenas, Chile. A total of 40 participants were evaluated, with 57.5% experiencing occasional stress and 10% experiencing frequent stress. While an increase in the vestibular index was observed in some participants, no significant correlations were identified between stress, physical performance, and balance. These findings suggest that perceived stress is not directly associated with physical performance or balance in older adults. Keywords: Aging, Perceived Stress, Postural Stability