Universidad de Magallanes
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Report on a new finding of a discoidal stone in the region of Pali-Aike, Magallanes
No full textResumen: Se presenta una descripción morfológica, técnica y traceológica de un lito discoidal proveniente de una colección privada, recolectado en las cercanías del sitio Cueva Fell. Los resultados se comparan con la información disponible para artefactos similares en Patagonia y Pampa
Inclusion of Sub-Antarctic Macroalgae (Gigartina skosttsbergii) as Feed Ingredient for Grazing Sheep
No full textTwo experiments were carried out to evaluate the inclusion impacts of macroalgae Gigartina skottsbergii (Gs) for grazing sheep. Experiment (Exp.) 1 studied the effect of Gs on in vitro gas production (IVGP), dry matter (DM) digestibility (IVDMD), and methane (CH4) emission using three fistulated sheep and 96 h incubation of samples. In Exp. 2, ten Dohne Merino ewes [5-year-old; 47 +/- 0.14 kg body weight (BW)] were randomly assigned to dietary treatments supplemented with Gs at 0 or 450 g DM/d per animal. The study lasted 31 days and was preceded by an adaptation period of 9 days. The BW, body conditional score (BCS), and blood were sampled at the first and the last day of the trial. The results of Exp. 1 showed that Gs supplementation reduced (MCP, p = 0.026) gas production (A), lag time (p = 0.013), and IVDMD (p = 0.071), while it enhanced partition factor (PF96; p = 0.004) and microbial crude protein (MCP) (p = 0.054). The concentration of CH4 decreased after 3 h (p = 0.0002), 6 h (p = 0.013), and 12 h (p = 0.010) with a tendency at 9 h (p = 0.109) and 24 h (p = 0.068). In Exp. 2, there were no diet effects on the initial BW (IBW, p = 0.77), final BW (FBW, p = 0.91), and average daily gain (ADG, p = 0.24) of ewes; however, Gs supplementation decreased BCS (p = 0.004). Of all blood parameters, only the concentration of glucose (p = 0.021) and albumin (p = 0.011) decreased in the Gs group. Overall, our results revealed that the dietary inclusion of Gs (at 450 g DM/d) affected neither the BW nor ADG of ewes; however, Gs was accompanied by lesser IVGP and CH4 emission
Sensitivity analysis of a mathematical model for the transmission of cystic echinococcosis
No full textCystic echinococcosis is a parasitic zoonosis endemic to Chile, involving a complex biological cycle between dogs, sheep, and humans; this study introduces a deterministic mathematical model to analyze the transmission and spread of the disease among these three groups. A sensitivity analysis of the basic reproduction number was performed using elasticity indices to quantify the impact of key parameters. The analysis revealed that the disease exit rate of infected dogs and the transmission rates between dogs and sheep are the most influential parameters affecting the basic reproduction number; these findings suggest that targeted measures, such as increasing the frequency of canine deworming and promoting campaigns to reduce transmission, could significantly mitigate the spread of cystic echinococcosis. The elasticity-based approach provides a framework for prioritizing intervention strategies and optimizing control efforts
Epistemically unwarranted beliefs scale, development and evidence of validity in the Chilean population
No full textThe study of epistemically unwarranted beliefs (EUB) (i.e., paranormal, pseudoscientific and conspiracy beliefs) has become relevant due to the negative effects they have produced on people's health, as evidenced in the covid-19 pandemic. However, there is no instrument with appropriate and updated validity evidence for its evaluation in Latin American people. Because of this, the present study aims to develop a brief scale to analyze general epistemically unwarranted beliefs that do not depend on local factors. A total of 634 adults from five Chilean cities participated in the study of whom 93.8% (n = 575) were university students. Exploratory and confirmatory factor analyses revealed that the final structure of the Epistemically Unwarranted Beliefs Scale (EUBS) considers 9 items with three related factors. In addition, results showed good internal consistency (CFI > .95; TLI > .95; RMSEA < .07), gender invariance, and evidence of validity based on the inverse relation with the cognitive reflection test and the relationship with sociodemographic variables (i.e., gender, political orientation, and religious orientation). Finally, implications for the theoretical construct and possible limitations of the scale are discussed
Reciprocal contributions: Indigenous perspectives and voices on marine-coastal experiences in the channels of northern Patagonia, Chile
No full textThe recovery of marine ecosystems in areas heavily impacted by fishing and environmental exploitation depends, to some extent, on the sustainable management of resources and should be complemented by cultural traditions, practices and scientific knowledge. These knowledge systems may involve reciprocal actions and interactions between people and coastal environments, which, unfortunately, are often overlooked in government coastal management strategies. Our study was conducted in the channels and fjords of northern Chilean Patagonia. The life experiences of nine community members, some of whom are co-authors of this article, involve reciprocal interactions with coastal areas and species. We highlight two customary practices that are important for food sovereignty and the responsible management of marine-coastal ecosystems. To understand their perspectives on nature, we analysed the ontological and cosmogonic aspects of these practices, their ecological implications and the challenges they currently face. We present two case studies: (i) the 'Corralitos de pirenes' in the Chiloé archipelago, which refers to small stone walls or enclosures built in the intertidal zone to create a suitable habitat for rockfish to spawn. The community consumes a percentage of the fish eggs, and the fish benefit by having a protected spawning site maintained by the locals; (ii) 'benthic rearrangements,' a practice carried out by shellfish divers who manually restructure underwater substrates that have been depleted by overexploitation of artisanal fishing. To this end, they manually relocate various species to re-establish their ecological interactions. Both cases demonstrate a deep, place-based ecological knowledge that fosters an understanding of ecosystems and fishing management rooted in the coastal families. These practices have been developed within family and community contexts and are continuously passed down through generations. These experiences embody a biocultural ethic that must be recognized, valued and expanded upon. Their ecological contributions (e.g. improvement of habitats) and socioecological endeavours (care for the environment) aim to foster biocultural continuity, engaging the elderly, adults and children. These experiences occur in a scenario of socio-environmental crises where industries, such as salmon farming, generate cultural and ecological impacts that intertwine both in time and within the depths of the sea.Read the free Plain Language Summary for this article on the Journal blog. La recuperación de los ecosistemas marinos en zonas muy afectadas por la pesca y la explotación ambiental depende, en cierta medida, de la gestión sostenible de los recursos y debe complementarse con tradiciones culturales, prácticas y conocimientos científicos. Estos sistemas de conocimiento pueden implicar acciones e interacciones recíprocas entre las personas y los entornos costeros que, por desgracia, a menudo se pasan por alto en las estrategias gubernamentales de gestión costera. Nuestro estudio se llevó a cabo en los canales y fiordos del norte de la Patagonia chilena. Las experiencias vitales de nueve miembros de comunidades indígenas, algunos de los cuales son coautores de este artículo, implican interacciones recíprocas con zonas y especies costeras. Destacamos dos prácticas consuetudinarias importantes para la soberanía alimentaria y la gestión responsable de los ecosistemas marino-costeros. Para comprender sus perspectivas sobre la naturaleza, analizamos los aspectos ontológicos y cosmogónicos de estas prácticas, sus implicaciones ecológicas y los retos a los que se enfrentan actualmente. Presentamos dos estudios de caso: (i) los > en el archipiélago de Chiloé, que se refieren a pequeños muros o recintos de piedra construidos en la zona intermareal para crear un hábitat adecuado para el desove de un pez roca. La comunidad consume un porcentaje de los huevos de los peces, yéstos se benefician al disponer de un lugar de desove protegido y mantenido por los lugareños; (ii) >, una práctica llevada a cabo por buzos mariscadores que reestructuran manualmente los sustratos submarinos que se han agotado por la sobreexplotación de la pesca artesanal. Para ello, reubican manualmente diversas especies para restablecer sus interacciones ecológicas. Ambos casos demuestran un profundo conocimiento ecológico basado en el lugar que fomenta una comprensión de los ecosistemas y de la gestión de la pesca consuetudinaria en las familias costeras. Estas prácticas se han desarrollado en contextos familiares y comunitarios y se transmiten continuamente de generación en generación. Estas experiencias encarnan unaética biocultural que debe ser reconocida, valorada y ampliada. Sus contribuciones ecológicas (por ejemplo, la mejora de los hábitats) y socioecológicas (el cuidado del medio ambiente) pretenden fomentar la continuidad biocultural, implicando a ancianos, adultos y niños. Estas experiencias se producen en un escenario de crisis socioambiental en el que las industrias, como la salmonicultura, generan impactos culturales y ecológicos que se entrecruzan tanto en el tiempo como en las profundidades del mar
Unveiling hidden molluscan diversity: New species records in Bougainville Bay, Strait of Magellan
No full textThe Chilean Fjords and Channels ecoregion presents unique oceanographic conditions that are sensitive to environmental impacts and socio-ecological systems. To assess how these impacts affect these ecosystems, it is essential to examine the current status of highly diverse taxa, such as molluscs, in terms of biodiversity and abundance, as they serve as valuable macroecological indicators of marine ecosystem health. On the southeastern margin of the Brunswick Peninsula, south of Punta Santa Ana, lies Cape Froward, where a system of eight small bays (< ca. 4 km2) is located, some of which are used as temporary harbours during navigation. Despite previous sampling efforts and existing records, these areas remain poorly described, with the region around Punta Santa Ana Bay being the most extensively documented. As part of monitoring programmes on coastal biodiversity in Magallanes and fishery resource assessments, sublittoral sampling was conducted in Bougainville Bay using autonomous diving (20 mdepth) and a modified Agassiz trawl (44 m depth). This study recorded 49 operational taxonomic units, comprising 32 gastropods, nine bivalves and eight polyplacophorans, all of which represent previously unpublished diversity records for this Bay. Additionally, these species were categorised, based on their feeding strategies, providing insights into their ecological roles. These findings also extend to neighbouring bays along the southern Brunswick Peninsula (from ElÁguila Bay to Cape Froward), where only two sublittoral species - the bivalves Zygochlamys patagonica and Philobrya sublaevis - had been previously documented. In the central micro-basin of the Strait of Magellan (from Second Narrows to Carlos III Island), this study introduces six new records: one bivalve and five gastropods, including two nudibranchs. All findings were compared with data from the Global Biodiversity Information Facility. These newly-documented records are crucial for understanding the biodiversity of molluscs inhabiting frequently navigated maritime areas, serving as indicators of anthropogenic impacts. This is especially relevant given the recent proposal of the area as a National Park
Tree-Cavity Denning of Güiña (Leopardus guigna) and Breeding Productivity From Camera Trap Records
No full textTree cavities are critical habitats for numerous vertebrate species, serving as keystone resources for nesting, roosting, and shelter. We document the first evidence of an individual güiña (Leopardus guigna) breeding within a tree cavity of a standing dead tree. We explore its implications on breeding productivity and complementing this record with evidence from camera trap surveys conducted in temperate forests of south-central Chile. These findings enhance our understanding of the species' natural history, breeding behavior, and habitat preferences. Additionally, we discuss the conservation implications of this discovery, offering new insights into the breeding ecology and habitat selection of one of South America's most elusive felines
Current Perspectives on Paroxysmal Nocturnal Hemoglobinuria (PNH)
No full textParoxysmal Nocturnal Hemoglobinuria (PNH) is a non-malignant clonal hematopoietic stem cell disorder characterized by intravascular and extravascular hemolysis, thrombosis, and potentially life-threatening systemic complications. Without treatment, the 5-year survival rate is approximately 50%. Advances in complement-inhibiting therapies have significantly improved the quality of life and survival of these patients. Aim: To review the pathophysiology, clinical presentation, diagnosis, and current and emerging treatments for PNH, highlighting the benefits of complement-inhibiting drugs. Methods: A literature review of the literature on the pathophysiology and treatments of PNH was conducted, covering studies from March 2010 to May 2024. The review included 42 articles from PUBMED/NCBI, of which 29 met the inclusion criteria and were selected for an in-depth analysis of pathophysiology, diagnosis, and therapeutic options. Results: Flow cytometry is the diagnostic method of choice for identifying PNH clones. Patients with classical PNH treated with C5 inhibitors (eculizumab and ravulizumab) exhibit an overall survival rate exceeding 95% at 5 years, with significant reductions in hemolysis, thrombotic episodes, and transfusion dependency. However, persistent extravascular hemolysis remains a challenge affecting morbidity and mortality. New proximal complement pathway inhibitors, such as iptacopan, have demonstrated greater efficacy in controlling extravascular hemolysis and improving hemoglobin levels. Conclusions: The introduction of complement-inhibiting therapies has transformed classical PNH from a fatal disease into a manageable chronic condition. It is essential to optimize access to these treatments and ensure adequate prophylaxis against encapsulated infections. New drugs expand therapeutic options, further improving clinical outcomes and patients' quality of life
Climate Change-Related Salinity Fluctuations and Warming Induce Physiological Stress and Cellular Alterations in an Antarctic Intertidal Brown Alga
No full textAntarctica is experiencing one of the fastest warming rates globally, profoundly impacting seawater temperature and salinity, with direct consequences for marine life. The present study examined the combined effects of salinity fluctuations at 20, 33 (control salinity), and 41 psu, and temperatures of 2 degrees C (control temperature) and 8 degrees C (thermal stress) for 3 days, on the health and physiology of the Antarctic intertidal macroalga Adenocystis utricularis. Photosynthetic activity, photoinhibition, and photoprotective processes were assessed alongside biomarkers of oxidative stress/damage (total ROS, lipid peroxidation, and protein carbonylation) and antioxidant/osmotic response (ascorbate, free amino acids, and proline). The results showed that maximum quantum yield (Fv/Fm) remained stable under both salinity and thermal stress. However, productivity (ETRmax), the photoprotection index (NPQmax), and irradiance saturation (EkETR) were significantly decreased at 8 degrees C, remaining constant under salinity fluctuations. At 2 degrees C, oxidative stress and damage were significantly higher under hypo- and hypersalinity conditions. However, at 8 degrees C, oxidative stress indicators decreased, accompanied by increased ascorbate levels in both hypo- (20 psu) and hypersalinity (41 psu) treatments compared to the control salinity. While warming temperatures negatively altered the oxidative response of A. utricularis at a 33 psu, we report here an interactive effect between salinity and temperature, leading to an altered stress response to salinity fluctuations under thermal stress. This study provides key information to better understand the adaptation of Antarctic intertidal macroalgae to multifactor climate change consequences
Palaeoglacial and palaeoclimate inferences from cirque morphometry and spatial distribution across northern Patagonia (40o-45o S)
No full textThe evolution of the cryosphere and climate in northern Patagonia during the late Pleistocene are relatively wellknown thanks to chronologies on ice-marginal features. However, this knowledge mainly represents the magnitude and duration of extreme cold intervals occurring during glacial maxima. Consequently, less is known about the state of the glaciers and climate during transitions between full glacial and interglacial stages. Given that morphometric attributes of glacial cirques are considered as robust indicators of palaeoglacial and palaeoclimate conditions during phases of minor glaciation, examining cirques will yield key insights to assess the typology of glaciers and associated climate conditions during those pivotal periods. In this study, we systematically analyzed the morphology and spatial distribution of 3081 cirques in northern Patagonia between-40o and-45o S. Our findings revealed that circular cirques, reflecting widespread long-lived small glaciers, dominate northern Patagonia. Eastward increase of cirque floor altitude from the coast to the continent along with prevailing east-to-south aspects indicate a key role of westerly-controlled climate and radiative balance in cirque development. Morphometry and spatial distribution of cirques along with statistical analyses indicate that annual total precipitation, minimum temperature, and incoming solar radiation altogether play a major role in cirque development in northern Patagonia, although the relative importance of these factors might vary spatially. Regional lithology exerts a secondary influence mostly in cirque geometry. We conclude that the most frequent state of the cryosphere within the Pleistocene glacial cycles in northern Patagonia is characterized by moderate glaciations similar to that existing during glacial terminations