Universidad de Magallanes
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Next steps to advance general physical activity recommendations towards physical exercise prescription: a narrative review
No full textPhysical inactivity is a major health concern, associated with the development of several non-communicable diseases and with an increased mortality rate. Therefore, promoting active lifestyles has become a crucial public health necessity for enhancing overall health and quality of life. The WHO guidelines for physical activity (PA) present valuable contributions in this respect; however, we believe that greater specificity should be added or complemented towards physical exercise (PE) testing, prescription and programming in future recommendations. In this review article, we suggest simple and practical tools accessible to the entire population to improve the specificity of this approach, highlighting aspects of PE programming used by trained subjects. By adopting these suggestions, exercise professionals, clinicians and physical trainers can optimise the current general PA recommendations towards PE prescription to improve fitness status and encourage PE adherence in the general population
Iron (hydr)oxide formation in Andosols under extreme climate conditions
No full textRedox-driven biogeochemical cycling of iron plays an integral role in the complex process network of ecosystems, such as carbon cycling, the fate of nutrients and greenhouse gas emissions. We investigate Fe-(hydr)oxide (trans)formation pathways from rhyolitic tephra in acidic topsoils of South Patagonian Andosols to evaluate the ecological relevance of terrestrial iron cycling for this sensitive fjord ecosystem. Using bulk geochemical analyses combined with micrometer-scale-measurements on individual soil aggregates and tephra pumice, we document biotic and abiotic pathways of Fe released from the glassy tephra matrix and titanomagnetite phenocrysts. During successive redox cycles that are controlled by frequent hydrological perturbations under hyper-humid climate, (trans)formations of ferrihydrite-organic matter coprecipitates, maghemite and hematite are closely linked to tephra weathering and organic matter turnover. These Fe-(hydr)oxides nucleate after glass dissolution and complexation with organic ligands, through maghemitization or dissolution-(re)crystallization processes from metastable precursors. Ultimately, hematite represents the most thermodynamically stable Fe-(hydr)oxide formed under these conditions and physically accumulates at redox interfaces, whereas the ferrihydrite coprecipitates represent a so far underappreciated terrestrial source of bio-available iron for fjord bioproductivity. The insights into Fe-(hydr)oxide (trans)formation in Andosols have implications for a better understanding of biogeochemical cycling of iron in this unique Patagonian fjord ecosystem
Antarctic Soil Yeasts with Fermentative Capacity and Potential for the Wine Industry
No full textLow fermentation temperatures are usually employed to obtain high-quality wines. This is especially interesting for white wine production since it prevents the loss of volatile compounds and a browning appearance; however, available fermentative yeasts do not usually tolerate low temperatures. Therefore, an interesting place to find new yeasts with cryotolerance is the Antarctic continent. From soil samples collected in Antarctica, 125 yeasts were isolated, of which 25 exhibited fermentative activity at 10 C-degrees. After a fingerprinting assay, we classified the candidates into nine isotypes and sequenced internal transcribed spacer regions for their identification. These yeasts were identified as part of the Mrakia genus. Sugar and alcohol tolerance tests showed that some of these Antarctic soil yeasts were able to grow up to 9% alcohol, and 25% sugar was reached; however, they exhibited longer latency periods compared to the control Saccharomyces cerevisiae. The optimal growing temperature for the isolated Antarctic yeasts was between 10 C-degrees and 15 C-degrees. A comprehensive analysis of the results obtained showed that the isolates 10M3-1, 4M3-6, and 4B1-35 could be good candidates for fermentation purposes due to their alcohol, sugar tolerance, and growth features. Our results prove that it is possible to isolate fermentative yeasts from Antarctic soil with promising characteristics for their potential use in the wine production industry
Trabajo y vida cotidiana de las cuadrillas loberas en Antártida a través de la arqueología histórica
No full textReseña de Archaeology in Antarctica. Andrés Zarankin, Michael Pearson y Melisa Salerno, 2023. Nueva York, Routledge, 262 pp. ISBN 978-0-367-19239-6
Preliminary Assessment of Sea Star (Echinodermata, Asteroidea) Diversity in the Coastal Magellanic Region (South Chile) and Their Geographical Distribution
No full textSea stars are a diverse and important component of the Southern Ocean benthos. However, scarce information is available regarding their diversity, distribution, evolution, and taxonomic uncertainties persist for multiple taxa. The Magellanic Region (south of Chile) remains under-sampled despite its pivotal location for species distribution and diversity, being located at the crossroad of three ocean basins. In this study, we assessed the biodiversity of coastal Magellanic sea stars and their affinities with other oceanic bioregions. An integrative approach combining morphological identification with DNA barcoding was implemented to highlight taxonomic discrepancies such as suspected synonymy and unrecognised diversity. Firstly, we identified a total of 15 species from the coastal Magellanic Region and reported the occurrence of Cycethra frigida Koehler, 1917 for the first time in this region. The distribution of these 15 species ranged from only in South America to circumpolar, bipolar, or possibly cosmopolitan. Secondly, we highlighted possible synonymy in two species pairs within the genera Anasterias and Odontaster. This preliminary biodiversity assessment forms an important baseline for monitoring and conservation purposes, especially in the face of distribution shifts as a response to climate change and the increased presence of invasive species. Developmental mode has previously been suggested to be important in shaping biogeographical patterns. However, developmental mode was insufficient to explain the observed patterns, and other factors (e.g., physiological constraints, competition, bathymetrical range, and the possibility of passively rafting on kelp) are suggested to be at least equally important. Finally, an increase in barcoding effort is needed to better capture phylogeographic patterns for each species, both by increasing the number of specimens investigated and by covering a broader geographical range
Carrageenan from Gigartina skottsbergii: A Novel Molecular Probe to Detect SARS-CoV-2
No full textThe COVID-19 pandemic has caused an unprecedented health and economic crisis, highlighting the importance of developing new molecular tools to monitor and detect SARS-CoV-2. Hence, this study proposed to employ the carrageenan extracted from Gigartina skottsbergii algae as a probe for SARS-CoV-2 virus binding capacity and potential use in molecular methods. G. skottsbergii specimens were collected in the Chilean subantarctic ecoregion, and the carrageenan was extracted -using a modified version of Webber's method-, characterized, and quantified. After 24 h of incubation with an inactivated viral suspension, the carrageenan's capacity to bind SARS-CoV-2 was tested. The probe-bound viral RNA was quantified using the reverse transcription and reverse transcription loop-mediated isothermal amplification (RT-LAMP) methods. Our findings showed that carrageenan extraction from seaweed has a similar spectrum to commercial carrageenan, achieving an excellent proportion of binding to SARS-CoV-2, with a yield of 8.3%. Viral RNA was also detected in the RT-LAMP assay. This study shows, for the first time, the binding capacity of carrageenan extracted from G. skottsbergii, which proved to be a low-cost and highly efficient method of binding to SARS-CoV-2 viral particles
The last two glacial cycles in central Patagonia: A precise record from the Nirehuao glacier lobe
No full textMilankovitch orbital parameters control cycles of insolation, a primary pacer of long term changes in climate, but exactly how insolation signals are transmitted around the globe in the climate system is unclear. In order to address the fundamental questions of when and how ice age climates begin and end, how fast glaciers retreated during the last deglaciation, and how glaciers behaved before anthropogenic influence, we need robust glacial chronologies. The timing of local glacial maxima beyond the last glacial cycle, however, has remained largely unconstrained due to moraine degradation over time, limiting our ability to fully explore these questions. By developing a detailed geomorphic surficial map and targeting relatively tall, ridge-top boulders, we have constructed a new, precise 10Be chronology of glacial maxima of the Nirehuao glacier lobe (45 degrees S) for the last two glacial cycles. We report one of the first directly dated records of a MIS 6 glacier advance in Patagonia, which formed a major set of moraines by at least 153 +/- 5.1 ka, with a stillstand or smaller readvance by 137 +/- 4.2 ka, corresponding to the two coldest and dustiest periods of MIS 6 in Antarctica. The next largest advance occurred at 23.6 +/- 0.9 ka, at the end of peak Southern Hemisphere MIS 2 cooling. Retreat of the glacier commenced by similar to 18.5 cal ka BP when lakes in a tributary valley just to the southwest became ice-free. Overall we find that advances of the Nirehuao glacier lobe occur when winter sea ice around Antarctica is expansive and both obliquity and eccentricity are at their minima. (c) 2022 Published by Elsevier Ltd
Long-term validation of Aeolus L2B wind products at Punta Arenas, Chile, and Leipzig, Germany
No full textGround-based observations of horizontal winds have been performed at Leipzig (51.35 degrees N, 12.43 degrees E), Germany, and at Punta Arenas (53.15 degrees S, 70.91 degrees W), Chile, in the framework of the German initiative EVAA (Experimental Validation and Assimilation of Aeolus observations) with respect to the validation of the Mie and Rayleigh wind products of Aeolus (L2B data). In Leipzig, at the Leibniz Institute for Tropospheric Research (TROPOS), radiosondes have been launched for the Aeolus overpasses on each Friday (ascending orbit) since the middle of May 2019. In Punta Arenas, scanning Doppler cloud radar observations have been performed in the framework of the DACAPO-PESO campaign (dacapo.tropos.de) for more than 3 years from the end of 2018 until the end of 2021 and could be used to validate Aeolus measurements on its ascending and descending orbits. We present two case studies and long-term statistics of the horizontal winds derived with the ground-based reference instruments compared to Aeolus horizontal line-of-sight (HLOS) winds. The wind products of Aeolus considered are the Mie cloudy and Rayleigh clear products. It was found that the deviation of the Aeolus HLOS winds from the ground reference is usually of Gaussian shape, which allowed the use of the median bias and the scaled median absolute deviation (MAD) for the determination of the systematic and random errors of Aeolus wind products, respectively. The case study from August 2020 with impressive atmospheric conditions at Punta Arenas shows that Aeolus is able to capture strong wind speeds of up to more than 100ms 1. The long-term validation was performed in Punta Arenas covering the period from December 2018 to November 2021 and in Leipzig from May 2019 until September 2022. This analysis showed that the systematic error of the Aeolus wind products could be significantly lowered during the mission lifetime with the changes introduced into the processing chain (different versions are called baselines). While in the early mission phase, systematic errors of more than 2ms 1 (absolute values) were observed for both wind types (Mie and Rayleigh), these biases could be reduced with the algorithm improvements, such as the introduction of the correction for temperature fluctuations at the main telescope of Aeolus (M1 temperature correction) with Baseline 09. Hence, since Baseline 10, a significant improvement in the Aeolus data was found, leading to a low systematic error (close to 0ms 1) and similar values for the midlatitudinal sites in both hemispheres. The random errors for both wind products were first decreasing with an increasing baseline but later increasing again due to performance losses of the Aeolus lidar instrument. Nevertheless, no significant increase in the systematic error in the Aeolus wind products was found. Thus, one can conclude that the uncertainty introduced by the reduced atmospheric return signal received by Aeolus mostly affects the random error. Even when considering all the challenges during the mission, we can confirm the general validity of Aeolus observations during its lifetime. Therefore, this space explorer mission could demonstrate that it is possible to perform active wind observations from space with the applied technique
Yendegaia Rockshelter, the First Rock Art Site on Tierra del Fuego Island and Social Interaction in Southern Patagonia (South America)
No full textThrough our research at Bahia Yendegaia on the Beagle Channel in southernmost Patagonia-the ancestral territory of the Yagan people-we discovered the first rock art site on Tierra del Fuego Island. The geometric visual images found at Yendegaia Rockshelter present motifs and compositions analogous to those recorded at other sites on the southern archipelago associated with the marine hunter-gatherer tradition. They also show graphic similarities to the rock art paintings attributed to terrestrial hunter-gatherer populations from the Pali Aike volcanic field, located on the north side of the Strait of Magellan in mainland Patagonia. Both, however, display quantitative differences, which suggest that they emerged from different visual traditions but from the same field of graphic solutions. Navigational technology enabled the canoe-faring Fuegian people to have long-distance mobility and to maintain a flow of social information mediated via visual imagery expressed in material forms, such as rock art and expressions of portable art. Ethnohistoric reports suggest a cooperative social interaction more than a competitive one. This cooperative social dynamic would have been necessary for the survival of marine societies in the harsh environmental conditions characteristic of the southern part of south Patagonia
Researchers' responsibility to uphold Indigenous rights Too often research brings harm to Indigenous peoples
No full textThe United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP), the most comprehensive international human rights instrument concerning Indigenous peoples, was adopted in 2007 by 144 countries to ensure protection of Indigenous rights and self-determination (1). While directed at states, UNDRIP should guide all levels of society. With governments lagging in its implementation, we argue that researchers-at universities, government institutions, consultancies, and elsewhere-have a responsibility to understand and advance these rights. As Indigenous and non-Indigenous researchers with backgrounds and experiences partnering with Indigenous peoples, we reviewed the articles of UNDRIP to identify those relevant to researchers. We summarized these into four themes: self-determination; free, prior, and informed consent; intellectual property; and engagement and learning. These articles provide a starting point for researchers to engage with and become allies in upholding Indigenous rights, in a way that supports Indigenous self-determination and sovereignty now and into the future