Universidad de Magallanes
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The role of machine learning in health policies during the COVID-19 pandemic and in long COVID management
No full textThe ongoing COVID-19 pandemic is arguably one of the most challenging health crises in modern times. The development of effective strategies to control the spread of SARS-CoV-2 were major goals for governments and policy makers. Mathematical modeling and machine learning emerged as potent tools to guide and optimize the different control measures. This review briefly summarizes the SARS-CoV-2 pandemic evolution during the first 3 years. It details the main public health challenges focusing on the contribution of mathematical modeling to design and guide government action plans and spread mitigation interventions of SARS-CoV-2. Next describes the application of machine learning methods in a series of study cases, including COVID-19 clinical diagnosis, the analysis of epidemiological variables, and drug discovery by protein engineering techniques. Lastly, it explores the use of machine learning tools for investigating long COVID, by identifying patterns and relationships of symptoms, predicting risk indicators, and enabling early evaluation of COVID-19 sequelae
Edward Osborne Wilson (1929-2021)
No full textAnales del Instituto de la Patagonia AIP es una revista científica que publica los resultados de investigaciones multidisciplinarias sobre biociencias tanto marina como terrestres, con especial énfasis en ecología, zoología, botánica y sus respectivas subdisciplinas aplicadas. Abordando estos temas en forma específica de cada disciplina o desde una forma transdisciplinaria
Regional variability in peatland burning at mid-to high-latitudes during the Holocene
No full textNorthern peatlands store globally-important amounts of carbon in the form of partly decomposed plant detritus. Drying associated with climate and land-use change may lead to increased fire frequency and severity in peatlands and the rapid loss of carbon to the atmosphere. However, our understanding of the patterns and drivers of peatland burning on an appropriate decadal to millennial timescale relies heavily on individual site-based reconstructions. For the first time, we synthesise peatland macrocharcoal re-cords from across North America, Europe, and Patagonia to reveal regional variation in peatland burning during the Holocene. We used an existing database of proximal sedimentary charcoal to represent regional burning trends in the wider landscape for each region. Long-term trends in peatland burning appear to be largely climate driven, with human activities likely having an increasing influence in the late Holocene. Warmer conditions during the Holocene Thermal Maximum (similar to 9e6 cal. ka BP) were associated with greater peatland burning in North America's Atlantic coast, southern Scandinavia and the Baltics, and Patagonia. Since the Little Ice Age, peatland burning has declined across North America and in some areas of Europe. This decline is mirrored by a decrease in wider landscape burning in some, but not all sub-regions, linked to fire-suppression policies, and landscape fragmentation caused by agricultural expansion. Peatlands demonstrate lower susceptibility to burning than the wider landscape in several instances, probably because of autogenic processes that maintain high levels of near-surface wetness even during drought. Nonetheless, widespread drying and degradation of peatlands, particularly in Europe, has likely increased their vulnerability to burning in recent centuries. Consequently, peatland restoration efforts are important to mitigate the risk of peatland fire under a changing climate. Finally, we make recommendations for future research to improve our understanding of the controls on peatland fires.(c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Contribution of Carotid Bodies on Pulmonary Function During Normoxia and Acute Hypoxia
No full textCarotid bodies (CBs) are main peripheral chemoreceptors involved in breathing regulation. Despite the well-known role played by CBs on breathing control, the precise contribution of CBs on the regulation of lung mechanics remains controversial. Accordingly, we study changes in lung mechanics in normoxia (FiO(2) 21%) and hypoxia (FiO(2) 8%) in mice with or without functional CBs. For this, we used adult male mice that underwent sham or CB denervation (CBD) surgery. Compared to sham-operated mice, we found that CBD induced an increase in lung resistance (RL) while breathing normoxic air (sham vs. CBD, p < 0.05). Importantly, changes in R-L were accompanied by an approximately threefold reduction in dynamic compliance (Cdyn). Additionally, end-expiratory work (EEW) was increased in normoxia in the CBD group. Contrarily, we found that CBD has no effect on lung mechanics during hypoxic stimulation. Indeed, R-L, Cd-yn, and EEW values in CBD mice were undistinguishable from the ones obtained in sham mice. Finally, we found that CBD induces lung parenchyma morphological alterations characterized by reduced alveoli space. Together our results showed that CBD progressively increases lung resistance at normoxic conditions and suggest that CB tonic afferent discharges are needed for the proper regulation of lung mechanics at rest
Steppe Ecosystems in Chilean Patagonia: Distribution, Climate, Biodiversity, and Threats to Their Sustainable Management
No full textSteppe ecosystems in Chilean Patagonia are located in the Andean rain shadow zones in the Aysén and Magallanes administrative regions, on the eastern slopes of the Andes along the border with Argentina, and in the north-central sector of Tierra del Fuego island. This chapter describes the distribution, climatic conditions, biodiversity, and changes in vegetation coverage of the steppe in Chile. Steppe biodiversity faces threats due to the negative impacts of multiple anthropogenic activities, particularly the development of the hydrocarbon sector, grazing pressure, wildfires, and the introduction of exotic species, as well as global climate change. Conservation of the Patagonian steppe in Chile depends both on protection within state parks or reserves and on cultural changes in the management of the unprotected area; economic uses and conservation must be integrated through sustainable management strategies
Anxiety and depression in community-dwelling elders with cardiovascular risk factors
No full textAbstract Funding Acknowledgements Type of funding sources: None. Introduction Elders with three or more cardiovascular risk factors (CVRF) are at an increased risk of suffering a cardiac event. Anxiety and depression have been proven to be important outcomes in elders. This study aimed to compare the level of anxiety and depression in elders with three or more CVRF vs. elders with less than three CVRF. Methods This was a cross-sectional study. 112 community-dwelling elders participated in this study. Sociodemographic characteristics, (age, sex, marital status), clinical outcomes (systolic and diastolic blood pressure, heart rate) and CVRF (hypertension, diabetes, dyslipidaemia, smoking, personal and family history of cardiac events) were assessed. Participants were divided in two groups: i) elders with three or more CVRF (n=46); ii) elders with less than three CVRF (n=66). We evaluated anxiety and depression using the Hospital Anxiety and Depression Scale. Results The age of the sample ranged from 60 to 88 years, 71,4% were women, and 55,4% were married. The participants who presented at least three CVRF significantly showed a higher level of depression (HADS-D, p = 0,009) than those who presented less than three CVRF. However, no differences in anxiety (HADS-A, p = 0,087) were obtained when comparing between-group differences. Conclusion Elders with at least three CVRF might show higher levels of depression than elders with less than three CVRF. It seems important to measure depression when assessing cardiac outcomes in community-dwelling elders, in order to establish specific programs and treatments for elders who present CVRF
Record-high Antarctic Peninsula temperatures and surface melt in February 2022: a compound event with an intense atmospheric river
No full textThe Antarctic Peninsula (AP) experienced a new extreme warm event and record-high surface melt in February 2022, rivaling the recent temperature records from 2015 and 2020, and contributing to the alarming series of extreme warm events over this region showing stronger warming compared to the rest of Antarctica. Here, the drivers and impacts of the event are analyzed in detail using a range of observational and modeling data. The northern/northwestern AP was directly impacted by an intense atmospheric river (AR) attaining category 3 on the AR scale, which brought anomalous heat and rainfall, while the AR-enhanced foehn effect further warmed its northeastern side. The event was triggered by multiple large-scale atmospheric circulation patterns linking the AR formation to tropical convection anomalies and stationary Rossby waves, with an anomalous Amundsen Sea Low and a record-breaking high-pressure system east of the AP. This multivariate and spatial compound event culminated in widespread and intense surface melt across the AP. Circulation analog analysis shows that global warming played a role in the amplification and increased probability of the event. Increasing frequency of such events can undermine the stability of the AP ice shelves, with multiple local to global impacts, including acceleration of the AP ice mass loss and changes in sensitive ecosystems
Activation of Intra-nodose Ganglion P2X7 Receptors Elicit Increases in Neuronal Activity
No full textVagus nerve innervates several organs including the heart, stomach, and pancreas among others. Somas of sensory neurons that project through the vagal nerve are located in the nodose ganglion. The presence of purinergic receptors has been reported in neurons and satellite glial cells in several sensory ganglia. In the nodose ganglion, calcium depletion-induced increases in neuron activity can be partly reversed by P2X7 blockers applied directly into the ganglion. The later suggest a possible role of P2X7 receptors in the modulation of neuronal activity within this sensory ganglion. We aimed to characterize the response to P2X7 activation in nodose ganglion neurons under physiological conditions. Using an ex vivo preparation for electrophysiological recordings of the neural discharges of nodose ganglion neurons, we found that treatments with ATP induce transient neuronal activity increases. Also, we found a concentration-dependent increase in neural activity in response to Bz-ATP (ED50 = 0.62 mM, a selective P2X7 receptor agonist), with a clear desensitization pattern when applied every similar to 30 s. Electrophysiological recordings from isolated nodose ganglion neurons reveal no differences in the responses to Bz-ATP and ATP. Finally, we showed that the P2X7 receptor was expressed in the rat nodose ganglion, both in neurons and satellite glial cells. Additionally, a P2X7 receptor negative allosteric modulator decreased the duration of Bz-ATP-induced maximal responses without affecting their amplitude. Our results show the presence of functional P2X7 receptors under physiological conditions within the nodose ganglion of the rat, and suggest that ATP modulation of nodose ganglion activity may be in part mediated by the activation of P2X7 receptors
A freshwater diatom perspective on the evolution of the southern westerlies for the past-14,000 years in southwestern Patagonia
No full textConflicting, even opposite interpretations on the evolution of the Southern Westerly Winds (SWW) are evident in paleoenvironmental records from southwestern Patagonia since the last ice age. These di-vergences call for new approaches utilizing different, ideally independent indicators of paleoenvir-onmental/paleoclimatic change from sensitive sites in climatically relevant locations. Here we present a multidecadally resolved diatom record from Lago Cipreses (51 degrees S), a small closed-basin lake located in a bedrock depression along the eastern foothills of the southern Patagonian Andes. The hydrological balance evolution of this isolated lake affords a direct tie with SWW intensity in a mountainous sector where zonal wind strength and local precipitation are highly correlated. We detect cold-tolerant diatoms (small fragilarioids) between-14-11.9 cal. ka BP followed by a shift to planktonic assemblages (Discostella pseudostelligera, Aulacoseira spp.) under warmer Holocene conditions. Diatom assemblages indicative of stratified water-column conditions (Discostella pseudostelligera, Achnanthidium aff tepidaricola, Achnan-thidium sieminskae) reached their maximum stability between-9.1-7.4 cal. ka BP. Stronger water-column mixing is evident by an abrupt species turnover to Aulacoseira spp. between-7.4-3.1 cal. ka BP, super-imposed on centennial-scale alternations between assemblages since-6.1 cal. ka BP. Cold-tolerant di-atoms resurge at-3.1 cal. ka BP and persist until the present. Our record offers assemblage-based evidence we interpret as sub-centennial to multimillennial scale changes in hydroclimate indicative of: (i) strong SWW influence between-14-11.9 cal. ka BP, (ii) a transition between-11.9-11.3 cal. ka BP to weak SWW influence between-11.3-6.5 cal. ka BP, with a SWW minimum between-9.1-7.4 cal. ka BP, and (iii) strong SWW influence since-6.5 cal. ka BP, with a Holocene SWW maximum since-3.1 cal. ka BP. We posit that enhanced hydroclimate variability since-6.1 cal. ka BP attests to the onset of Southern Annular Mode-like changes at centennial-to sub-centennial timescales. We detect a remarkably coherent and synchronous response of terrestrial and aquatic ecosystems at local scale since-14 cal. ka BP, highlighting the overriding importance of variations in SWW influence in terrestrial and aquatic envi-ronments at multiple timescales.(c) 2022 Elsevier Ltd. All rights reserved
Benthic biota of Chilean fjords and channels in 25 years of cruises of the National Oceanographic Committee
No full textThe CIMAR program (Marine Research Cruises to Remote Areas) run by the Chilean Navy through the National Oceanographic Committee has been developed since 1995, focused on Chilean fjord and channel zones (similar to 41-56 degrees S; "CIMAR-Fjords") and Chilean remote islands ("CIMAR-Islands"). Samples and data was collected on biotic and abiotic variables on all these cruises, both from the water column and benthos. Our work standardizes, compiles, and summarizes the published information on benthic organisms for twenty-one CIMAR-Fjords cruises developed in the first 25 years of the program, plus the Southern Ice Fields Cruise 1995 (precursor of the CIMAR program), which includes the distribution, abundance and geographic location of cruises sampling stations. The data set includes 8,854 records from 880 different localities, corresponding to 1,225 species from 24 different phyla (four kingdoms) and more than 150,000 individuals. Only two cruises did not record any benthic sampling. The fjords and channels of Chilean Patagonia have high biodiversity, so we hope that our data set will serve as a baseline for ecological studies and ecosystem conservation