Universidad de Magallanes
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The Importance of a Glacier Complex for Downstream Runoff in the Semiarid Chilean Andes During Dry Years
No full textHigh mountain catchment systems are inherently complex and include multiple processes that influence runoff generation, making it challenging to assess their current state and project their future solely based on observed data. However, combining observations with hydrological models that can simulate glacio-hydrological processes robustly offers a solution to this issue. This study focused on analysing and characterising the snow, glacier and runoff processes of the Tapado Glacier sub-catchment, an upstream source of the La Laguna reservoir in the semiarid Chilean Andes (30 degrees S) for 2019-2021. For this purpose, a semi-distributed physical model (Cold Regions Hydrological Model [CRHM]) was used to simulate glacio-hydrological processes. The results indicate that sublimation accounted for 66%-89% of snow ablation, limiting the amount of snow available for melting in summer, and making melt from Tapado Glacier the primary component of mid-summer (January) discharge (28%-55%). This was reflected in significant mass loss from the Tapado Glacier ablation zone (-0.5 to -2.1 m w.e.). Sensitivity analyses indicated that precipitation and snow roughness generated the greatest variability in simulations related to snow mass balance process. Uncertainty due to errors in precipitation measurement and extrapolation is inherent in hydrological modelling in most mountain settings, whilst the uncertainty related to snow roughness (evaluated range: 0.0001-0.1 m) is largely due to its direct influence on snow sublimation rates and the challenges associated with measuring this variable. For the glaciated areas, results were sensitive to the selection of ice albedo. Whilst the Tapado sub-catchment includes only 1% of the catchment feeding the La Laguna reservoir (c.a. 27 km downstream), it equates to 6%-26% of monthly inflow into the reservoir over the study period. This indicates the importance of glaciated regions for supporting baseflow during relatively dry periods
Living in times of coronavirus: Relationships, information, and perceptions during the pandemic in Mexico
No full textBased on data from nurses, teachers, unemployed individuals, small traders, and COVID-19 survivors, this chapter examines the impact of public health public health measures during the COVID-19 pandemic in Mexico. The study focuses on information sources, care work (especially domestic), trust in vaccines, mental health, and preventive measures. Findings reveal that people effectively identified reliable information sources, facilitating the adoption of preventive measures recommended by experts. While vaccine acceptance grew over time, initial skepticism was noted. The study also highlights the complex nature of care work in post-pandemic life and emphasizes the critical importance of mental health, recognizing it as both a medical and public health priority. Further research is needed to understand care work's multidimensional role in daily life
The role of host mobility in the transmission and spread of Echinococcus granulosus: A Chile-based mathematical modeling approach
No full textThis paper explores, as a proof-of-concept, the impact of definitive and intermediate host mobility on the transmission and spread of cystic echinococcosis by characterizing disease dynamics using three classical epidemic models: S-E-I-R for the accidental intermediate host, S-E-I for the habitual intermediate host, and S-I-S for the definitive host. The simulations revealed a significant relationship between the mobility of dogs and the increase in infected sheep. Specifically, for each infected dog, there were twice as many infected sheep as in a situation where mobility was not a factor. The initial conditions took into account that the prevalence of the disease in dogs is higher in rural areas than in peri-urban areas, as has been observed in the Magallanes region of Chile. The results of the simulations suggest that mobility can have a role in the propagation of the disease in humans. Furthermore, the sensitivity index on R0 indicates that a 10% reduction in the average time spent by peri-urban dogs in urban and rural areas could result in a decrease of approximately 1% in R0. In conclusion, including the host mobility factor allows us to observe that, in general, the number of infected in the domestic cycle of the disease increases, i.e., our mathematical model provides valuable information on the impact of host mobility on the transmission and spread of cystic echinococcosis
Obsidian Technology and Transport Along the Archipelago of Southernmost South America (42-56° S)
No full textObsidian was a key toolstone for the development of maritime lifeways in the western archipelago of southernmost South America. This area is a fragmented landscape where the major north-south movement of people along the Pacific was only possible by navigation because it is constrained by major biogeographic barriers. Two obsidian sources have been recorded, each one located on the extremes of the archipelago, and each has played a key role in the canoe-adapted societies that used them. As indicated by repeated inductively coupled plasma mass spectrometry analyses, obsidian from Chaitén Volcano to the north was distributed between 38 degrees 26 ' S and 45 degrees 20 ' S, and obsidian from Seno Otway to the south was distributed between 50 degrees and 55 degrees S, although it mainly occurred in sites close to the Strait of Magellan and within constrained time periods. This study explores the distribution of these two types of obsidians, their chronology, their frequencies in the archaeological record, the main artifact classes that are represented, and the technological processes in which they were involved. This examination indicates common aspects in the selection of high-quality toolstones for highly mobile maritime groups and discusses the different historical trajectories of two obsidians that appear decoupled across the Holocene
Exo70 Protects Against Memory and Synaptic Impairments Following Mild Traumatic Brain Injury
No full textMild traumatic brain injury (mTBI), a leading cause of disability in young adults, often results from external forces that damage the brain. Cellularly, mTBI induces oxidative stress, characterized by excessive reactive oxygen species (ROS) and diminished antioxidant capacity. This redox imbalance disrupts hippocampal glutamatergic transmission and synaptic plasticity, where NMDA receptors (NMDARs) are crucial. The exocyst, a vesicle tethering complex, is implicated in glutamate receptor trafficking. We previously showed that Exo70, a key exocyst subunit, redistributes within synapses and increases its interaction with the NMDAR subunit GluN2B following mTBI, suggesting a role in GluN2B distribution from synaptic to extrasynaptic sites. This study investigated whether Exo70 could mitigate mTBI pathology by modulating NMDAR trafficking under elevated oxidative stress. Using a modified Maryland mTBI mouse model, we overexpressed Exo70 in CA1 pyramidal neurons via lentiviral transduction. Exo70 overexpression prevented mTBI-induced cognitive impairment, assessed by the Morris water maze. Moreover, these mice exhibited basal and NMDAR-dependent hippocampal synaptic transmission comparable to sham animals, preventing mTBI-induced deterioration. Preserved long-term potentiation, abundant synaptic GluN2B-containing NMDARs, and downstream signaling indicated that Exo70 overexpression prevented mTBI-related alterations. Our findings highlight Exo70's crucial role in NMDAR trafficking, potentially counteracting oxidative stress effects. The exocyst complex may be a critical component of the machinery regulating NMDAR distribution in health and disease, particularly in pathologies featuring oxidative stress and NMDAR dysfunction, like mTBI
Acoustic Emissions from Grey Glacier, Chilean Patagonia: dataset of infrasound measurements
No full textCalving is a critical process contributing to ice mass loss in tidewater and lake-terminating glaciers, with significant implications for freshwater input, glacier dynamics, and climate change. Infrasound emissions generated by calving events represent a powerful tool for monitoring, quantifying, and understanding the mechanisms that drive glacier retreat. In this study, we present the first acoustic dataset collected over a six-day period during the austral summer at Grey Glacier, located in Torres del Paine National Park, Chile. We provide a detailed description of the instrumentation setup, data acquisition procedures, and signal processing methodologies. By applying high-sensitivity infrasound array processing techniques, we demonstrate that coherent signals generated by calving events can be reliably extracted from the acoustic data, despite environmental conditions, such as strong winds that affect infrasound propagation. This dataset represents a valuable resource for advancing research on cryosphere dynamics and offers practical applications for the glaciological and geophysical communities
Environmental consequences of interacting effects of changes in stratospheric ozone, ultraviolet radiation, and climate: UNEP Environmental Effects Assessment Panel, Update 2024
No full textThis Assessment Update by the Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme (UNEP) addresses the interacting effects of changes in stratospheric ozone, solar ultraviolet (UV) radiation, and climate on the environment and human health. These include new modelling studies that confirm the benefits of the Montreal Protocol in protecting the stratospheric ozone layer and its role in maintaining a stable climate, both at low and high latitudes. We also provide an update on projected levels of solar UV-radiation during the twenty-first century. Potential environmental consequences of climate intervention scenarios are also briefly discussed, illustrating the large uncertainties of, for example, Stratospheric Aerosol Injection (SAI). Modelling studies predict that, although SAI would cool the Earth's surface, other climate factors would be affected, including stratospheric ozone depletion and precipitation patterns. The contribution to global warming of replacements for ozone-depleting substances (ODS) are assessed. With respect to the breakdown products of chemicals under the purview of the Montreal Protocol, the risks to ecosystem and human health from the formation of trifluoroacetic acid (TFA) as a degradation product of ODS replacements are currently de minimis. UV-radiation and climate change continue to have complex interactive effects on the environment due largely to human activities. UV-radiation, other weathering factors, and microbial action contribute significantly to the breakdown of plastic waste in the environment, and in affecting transport, fate, and toxicity of the plastics in terrestrial and aquatic ecosystems, and the atmosphere. Sustainability demands continue to drive industry innovations to mitigate environmental consequences of the use and disposal of plastic and plastic-containing materials. Terrestrial ecosystems in alpine and polar environments are increasingly being exposed to enhanced UV-radiation due to earlier seasonal snow and ice melt because of climate warming and extended periods of ozone depletion. Solar radiation, including UV-radiation, also contributes to the decomposition of dead plant material, which affects nutrient cycling, carbon storage, emission of greenhouse gases, and soil fertility. In aquatic ecosystems, loss of ice cover is increasing the area of polar oceans exposed to UV-radiation with possible negative effects on phytoplankton productivity. However, modelling studies of Arctic Ocean circulation suggests that phytoplankton are circulating to progressively deeper ocean layers with less UV irradiation. Human health is also modified by climate change and behaviour patterns, resulting in changes in exposure to UV-radiation with harmful or beneficial effects depending on conditions and skin type. For example, incidence of melanoma has been associated with increased air temperature, which affects time spent outdoors and thus exposure to UV-radiation. Overall, implementation of the Montreal Protocol and its Amendments has mitigated the deleterious effects of high levels of UV-radiation and global warming for both environmental and human health
ATTITUDES TOWARD MATHEMATICS IN BUSINESS ADMINISTRATION STUDENTS: AN EXPLORATORY STUDY
No full textEste estudio analiza las actitudes hacia la matemática de los estudiantes de carreras del área de administración pertenecientes a un instituto profesional en Punta Arenas, Chile, y su relación con las experiencias de aprendizaje en la asignatura. A partir de una muestra de 92 estudiantes, se observó que, en general, presentan una actitud positiva hacia la matemática; sin embargo, existe una alta variabilidad en sus respuestas, destacándose un grupo con actitudes negativas. Los estudiantes perciben una alta utilidad de la matemática, pero también presentan niveles moderados de ansiedad, confianza y motivación. A través de un análisis de componentes principales (PCA), se identificaron tres grupos con actitudes diferenciadas, desde aquellos con mayor ansiedad y baja confianza hasta quienes tienen una percepción más positiva. También se encontró que quienes perciben mayor utilidad en la matemática tienden a experimentar más agrado y confianza; no obstante, reducir la ansiedad no necesariamente mejora estas dimensiones
Relationship Between Body Mass Index and Fat Mass Percentage with Proprioception in Children
No full textBackground/Objectives: Childhood obesity is linked to motor and sensorimotor impairments, including proprioceptive deficits. While research has predominantly focused on lower limb proprioception, less is known about the impact on upper limbs. This study investigated the relationship between body mass index, body fat percentage, and proprioception of children aged 11-12 years. Methods: A quantitative, correlational, observational design was employed. BMI was calculated from weight and height measurements, body fat percentage was assessed via bioelectrical impedance analysis, and proprioception was measured using an active repositioning test with inertial sensors in 44 children. Results: Significant correlations were found between BMI and positional errors in the shoulder (r = 0.64, p < 0.001), elbow (r = 0.36, p = 0.007), and knee (r = 0.42, p = 0.002). Regarding body fat percentage, significant correlations were observed with positional errors in the shoulder (r = 0.28, p = 0.031), elbow (r = 0.46, p < 0.001), and knee (r = 0.29, p = 0.030). Regression analysis showed that BMI and body fat percentage significantly predicted positional errors in the shoulder, elbow, and knee. In the shoulder joint, girls demonstrated lower positional errors compared to boys, influenced by both BMI (beta = -1.36, p = 0.015) and body fat percentage (beta = -3.00, p < 0.001). Conclusions: Higher BMI and body fat percentage are associated with shoulder, elbow, and knee joint proprioceptive deficits. Interventions targeting weight reduction and proprioceptive training may mitigate these deficits and promote sensorimotor function in children
Deterioro cognitivo y ansiedad en adultos mayores: caracterizaciones en una población de latitudes altas del sur
No full textAbstract Objective. The study characterized the levels of anxiety and cognitive impairment of older people in the Chilean city of Punta Arenas, exploring possible correlations between both phenomena. Methods. With a descriptive pilot design, 72 older people (60-87 years) residing in Punta Arenas were evaluated using the Beck Anxiety Inventory (BAI) and Montreal Cognitive Assessment (MoCA) tests to measure anxiety and cognitive impairment, respectively. Results. Women were found to have significantly higher BAI scores than men (9,0 vs 3,5; p = 0,025), without significant differences in MoCA by sex. BAI and MoCA total scores showed an inverse correlation. Those over 70 years of age had a greater probability of altered scores in BAI, and a non-significant trend in MoCA (OR: 2.43; p = 0.066). Men showed higher rates of cognitive deterioration than women, although without statistical significance. Conclusion. Those over 70 years of age showed a greater probability of altered anxiety and a non-significant trend toward greater cognitive deterioration. The results underscore the need for specific interventions to improve mental and cognitive health in this vulnerable population