Universidad de Magallanes
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Brainstem C1 neurons mediate heart failure decompensation and mortality during acute salt loading
No full textAims Heart failure (HF) is an emerging epidemic worldwide. Despite advances in treatment, the morbidity and mortality rate of HF remain high, and the global prevalence continues to rise. Common clinical features of HF include cardiac sympathoexcitation, disordered breathing, and kidney dysfunction; kidney dysfunction strongly contributes to sodium retention and fluid overload, leading to poor outcomes of HF patients. We have previously shown that brainstem pre-sympathetic neurons (C1) from the rostral ventrolateral medulla (RVLM) play a key role in sympathetic regulation in experimental models of HF. However, the role of RVLM-C1 neurons during salt-loading in the context of HF is unknown. This study tests whether RVLM C1 neurons drive cardiorespiratory decompensation and ultimately lead to sudden death in HF rats.Methods and results Adult male Sprague-Dawley rats underwent arteriovenous shunt to induce HF with preserved ejection fraction (HFpEF). Two weeks after HFpEF induction, bilateral selective ablation of RVLM C1 neurons was performed using anti-dopamine beta-hydroxylase-saporin toxin. Animals were then fed a high Na+ diet (3% Na+ in food and 2% Na+ in water) for 3 weeks to induce compensated-to-decompensated HF state transition. Echocardiography, cardiac autonomic function, breathing function, and survival were assessed during the progression of HF. Salt loading resulted in marked decompensation in HF rats, as evidenced by a significant decrease in survival rates (survival: 10% vs. 100% HFpEF + Na+ vs. HFpEF). Furthermore, HFpEF + Na+ animals showed a further increase in cardiac sympathetic drive and more severe disordered breathing, including higher hypoxia-related epochs (i.e. apnoeas/hypopnoeas), compared with HF. Ablation of RVLM C1 neurons partly reduced the excessive cardiac sympathoexcitation during salt loading in HF, improved the exaggerated disordered breathing in HFpEF+ Na+ rats, and reduced decompensation-linked mortality. We found that hypoxia, but not high sodium, was the major contributor to impaired calcium handling in isolated adult cardiomyocytes.Conclusion Our results strongly suggest that RVLM C1 neurons contribute to acute HF decompensation during salt loading by a mechanism encompassing further increases in sympathetic outflow and hypoxia-related breathing disorders. This mechanism may ultimately impact cardiac contractility through cardiomyocyte calcium mishandling, increasing morbidity and mortality
Reconstruction of oceanographic and climatic changes over the past ∼ 600 years over Coquimbo Bay, Chile (30°S)
No full textThe upwelling system off Coquimbo (30 degrees S) is strongly influenced by interannual variability driven by the El Nino-Southern Oscillation (ENSO), which decreases primary productivity and increases precipitation during the warm phase (El Nino events). This study examined the historical variations in the primary oceanographic and climatic characteristics of the region based on recent sedimentary records from Coquimbo Bay. In a sediment core (BC117; 83 cm), nine sedimentary units were identified and categorized into two groups: u1, u3, u5, and u9 represent marine sedimentation, as indicated by the major contribution of marine diatoms and higher delta C-13 and delta N-15 values reflecting marine conditions. In contrast, u4, u6 and u7 exhibited more depleted delta 13C values and an increase in freshwater diatom valves, suggesting a significant continental influence, likely from alluvial events. These units showed elevated concentrations of Fe, K, and Cu and an increase in fine sediment content, likely associated with El Nino-induced heavy rainfall around 1700-1730 CE. This period was followed by a decrease in continental input owing to reduced pluviosity. Spanning from 1403 CE to 1850 CE, the core reflects a period dominated by La Nina-like conditions, sustained by an intensified Southern Oscillation Index (SOI) and diminished Interdecadal Pacific Oscillation (IPO). During this period, the seafloor experienced an increase in reduced conditions, likely leading to anoxic environments, which were subsequently followed by less reduced conditions encompassing the Current Warm Period (CWP) due to enhanced ventilation processes. Nevertheless, increasing proxies for primary productivity have suggested an intensification of upwelling in recent times. Based on the characteristics of the units, three tsunami events were characterized by a significant reduction in total diatom counts contingent on the energy of the event and a sharp basal contact between the lower undisturbed unit and the very disturbed overlying layer (1420, 1471, and 1751 CE)
The role of the huemul (Hippocamelus bisulcus) in Patagonian maritime hunter-gatherer strategies: The case of Diego Portales Island and ultima Esperanza inland sea (Chile)
No full textThe biodiversity of animal species in the ultima Esperanza inland sea (Magallanes region, Chile) provides an exceptional opportunity to study the economic and organizational strategies of maritime hunter-gatherer groups in the Fuego-Patagonian archipelago. The consumption of huemul (Hippocamelus bisulcus) in Southern South America is well documented since the Middle Holocene, although its role in the subsistence strategies of maritime hunter-gatherers varies depending on the geographical and environmental area. The aim of this paper is to assess the implications of huemul exploitation on organizational strategies by Late Holocene maritime hunter-gatherer groups from the ultima Esperanza inland sea (Magallanes region, Chile). In this work we present the results of a zooarchaeological analysis of the huemul assemblage from the sites of Bahia Easter 1 and Bahia Easter 2 (Diego Portales Island, ultima Esperanza, Chile). The results show the high importance of huemul in the maritime hunter-gatherer diet, and provide new insights into the hunting and transport strategies of this prey. Furthermore, the integration of the data within the local and regional archaeological record allowed us to identify similarities at the scale of the inland sea, where huemul was frequently exploited both in island and coastal environments in contrast to what is documented in the neighboring Skyring Sea and Otway Sea
Berberis microphylla G. Forst: a Chilean renewable source of cholinesterases and prolyl oligopeptidase inhibitors
No full textCholinesterase inhibitors are an important therapeutic Alzheimer disease strategy. Consequently, many research groups have focused their studies on finding new target or bioactive molecules for controlling this neurodegenerative disorder. In this regard, prolyl oligopeptidase (POP) has been considered a target on diseases in which cognitive capabilities are affected. Therefore, the objective of this study was to evaluate Berberis microphylla G. Forst. alkaloidal extract, berberine, palmatine and jatrorrhizine inhibitory activity on POP, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) by in silico and in vitro methodologies. It was found that B. microphylla alkaloidal extract was a potent inhibitor of AChE with an IC50 value of 3.62 mu g/mL. To better understand the bioactivity of some alkaloids against AChE, BuChE and POP, a molecular docking approach was performed. The role of B. microphylla as source of AChE, BuChE and POP inhibitors is further discussed in this study
Chilean Biobanks: A Snapshot of the Current Landscape
No full textLatin America hosts extraordinary biological diversity but remains underrepresented in global biomedical research, underscoring the need for robust biobanking infrastructures. This work provides an updated snapshot of Chilean biobanks, based on a national survey exploring their current capacities and challenges. Nine active biobanks were identified across 5 of Chile's 16 regions, the majority concentrated in Santiago. Collectively, they store over 640,000 biospecimens from nearly 49,000 participants, predominantly oncological. While standardized protocols for sample management are broadly implemented by Chilean biobanks, data management practices are not yet well-developed, as only a few centers have adopted internationally recognized standards. Governance structures vary considerably and often lack formal written documentation. Financial sustainability relies mainly on institutional support, competitive grants, and modest cost recovery. Although Chilean biobanks contribute to research and training, measuring productivity remains challenging due to underreported acknowledgments and limited post-transfer traceability. Overall, our analysis suggests a bottom-up development of Chilean biobanks in the absence of dedicated legislation or strategic governmental policies. This overview shows that Chile's biobanks hold considerable potential for strengthening translational research and health equity, particularly if further support enables expansion into underrepresented regions. By integrating these infrastructures into higher education, clinical care, and broader regional collaborations, biobanks can help leverage Chilean genetic diversity and address health disparities. With greater governmental prioritization, a cohesive regulatory framework, and collaboration as a key strength, biobanks could enhance interaction with global networks and further strengthen Latin America's overall contribution to biomedical innovation
Dating the ebb and flow of Tiwanaku and post-collapse material culture across the Andes
No full textThis paper presents a comprehensive Bayesian refinement of the chronology of Tiwanaku material culture. To place this material pattern in space, we present a presence-only map of most sites with Tiwanaku redware ceramics, snuff trays, and textiles. We compile radiocarbon dates and assess their material associations before building Bayesian models. We present bespoke calibration curve mixtures for each major region, based on air mixtures from climate models. The models suggest that redwares burst onto the scene in the AD 600s in the Lake Titicaca Basin (Peru and Bolivia) and around the same time, snuff trays with the same iconography appeared in burials at San Pedro de Atacama (Chile). Other parts of the Andes first saw this material culture later, and only in the AD 900s was it clearly present in all regions. Around similar to AD 1040, Tiwanaku redwares were no longer used at Tiwanaku or in Moquegua. Residents of the Western Valleys immediately innovated new post-collapse styles derived from Tiwanaku redwares, appearing and fading away at different times in different valleys. A small community near Lake Titicaca maintained old traditions for generations, including the use of raised fields and Tiwanaku burials. We assess temporal alignments and disjunctures in order to highlight variability of Tiwanaku material culture, long assumed to be fairly homogeneous over space and time. This opens the door to more nuanced, generation-scale questions about the interaction networks that assembled and disassembled Tiwanaku
Determinantes de la Disposición a Buscar Ayuda Académica en Estudiantes Universitarios Chilenos: Un Análisis de Modelo Estructural
No full textThrough a structural model, this study analyzed how personal and contextual variables explain the student's willingness to seek institutional academic help. The study involved 848 students of both sexes from public and private Chilean universities. The participants responded to a questionnaire evaluating personal (enabling and inhibitory) and contextual variables. Based on previous evidence from the literature and preliminary regression analysis, an explanatory model of the willingness for academic help-seeking was proposed and evaluated through a structural model (SEM). The results show a good fit of the final model, highlighting direct and indirect determinants of the student's willingness for academic help-seeking and the mediator role of knowledge of access procedures to institutional support services. Also, and against expectations, a slight effect of shame on willingness to institutional help-seeking was observed. Finally, the implications of having a parsimonious model to explain this process are discussed
Nurturing forest memory: native bamboo as an assemblage of biocultural keystone species in the southern Andes
No full textPresently, with the acceleration of climate change and rural land development, foraging spaces remain increasingly under threat. In Andean temperate forests of southern Chile, these challenges, coupled with ongoing legacies of colonization, threaten the biocultural memory of an assemblage of foundational understory species, the Chusquea spp. Both the commonly named species kila (Chusquea quila) and koliwe (Chusquea culeou) stand out for their ecological importance and, moreover, for their historical usage and significance among Mapuche and campesino communities. To better understand the biocultural importance of the Chusquea spp., we implemented a biocultural keystone species assessment among Mapuche and campesino communities. Moreover, drawing from community-based participatory frameworks, we collaborated with local foragers to synthesize recommendations for best management practices and develop guidelines to identify high-quality harvestable Chusquea spp. To conduct the biocultural keystone species assessment and synthesize management recommendations, we carried out participant observation, informal interviews, and snowball sampling, and conducted ethnographic interviews and fieldwork assessments with 16 expert foragers across the Mallolafken watershed in the La Araucanía region, southern Andes of Chile. Our results identified the Chusquea spp. as an assemblage of biocultural keystone species, with 62 household uses, critical contributions to food security, ceremonial significance, and cultural roles as a messenger, protector, and companion. Consultation with foragers also determined harvesting guidelines in accordance with use type based principally on variations in (1) color, (2) diameter, and (3) leaf abundance. While few foragers actively manage Chusquea spp. aside from using animal grazing to prune and control growth, some foragers shared techniques for reproducing stands. The lack of salient Traditional Ecological Knowledge related to Chusquea spp. management reflects their threatened biocultural memory. Future research coupled with community outreach regarding Chusquea spp. management is needed to support foraging practices and forest conservation efforts in the region
Effects of burn severity on the diversity and relative abundance of birds 3-years postfire in a coastal forest of Nothofagus glauca (Phil.) Krasser in central Chile
No full textHigher temperatures and more extended dry periods due to climate change are increasing the frequency and severity of fires in Mediterranean zones. Little is known about the impact of fire on bird communities in this ecosystem of Chile. In this study, we assessed bird diversity and relative abundance on field plots representing different burn severity levels (unburned, low severity, medium severity, and high severity) on a coastal forest of Nothofagus glauca (Phil.) Krasser in central Chile. This study was conducted during the summer of 2020, three years postfire. In total, thirty-two bird species were found in this forest type, and the relative abundance by species varied from 0.2 to 18 individuals per hectare. We found no significant effect of burn severity on bird diversity 3-years since the fire. However, the responses of relative abundance to the burn severity levels differed by species. Overall, the relative abundance of some species did not differ with the burn severity; other species declined in their relative abundance when burn severity increased, while other species showed an inconsistent non-monotonic pattern. While several bird species did not vary in relative abundance with the fire severity, others exhibited a high vulnerability, results that can guide the active restoration and species conservation of this type of ecosystem
A Framework for the Design and Selection of Quick-Action Drives in Dynamic Mode for Advanced Manufacturing Systems
No full textNumerous types of manufacturing equipment operate predominantly in the transient regime, where productivity relies on the rapid response of their drive systems. Therefore, selecting an appropriate drive system for applications with short displacement time cycles is crucial for optimizing manufacturing performance. This work introduces a novel selection methodology that integrates two complementary approaches for an optimal choice of quick-action drives in advanced manufacturing systems, including robotic drive mechanisms. The Transient Power - Double Kinetic Energy Method (P'-2K Method) and the Torque - Electromechanical Time Constant Method are systematically combined to enhance selection accuracy. A key advantage of this methodology, which consists of a seven-step method proposed, is that it simultaneously considers the influence of all electromechanical parameters on drive system dynamic performance, an aspect often overlooked by previous methods. The proposed methodology is also demonstrated by selecting and implementing the drive system for a CNC Punching Machine developed within an R&D project funded by the Colombian National Science Foundation (MinCiencias). The dynamic models obtained were implemented in an engineering application to simulate drive performance using data from manufacturers' catalogs, allowing a comparative evaluation of different drive system alternatives. The case study analysis identifies the advantages, limitations, and complementarity of the two methods, highlighting their potential for improving the efficiency and responsiveness of automated manufacturing processes. Furthermore, this study outlines additional considerations necessary for achieving an optimized design of drive systems in high-speed transient manufacturing applications