Holocene tephrochronology around Cochrane (~47° S), southern Chile

Two Holocene tephras encountered in outcrops, cores and trenches in bogs, and lake cores in the area around Cochrane, southern Chile, are identified (based on their age, tephra glass color and morphology, mineralogy, and both bulk and glass chemistry) as H1 derived from Hudson volcano, and MEN1 derived from Mentolat volcano. New AMS radiocarbon ages indicate systematic differences between those determined in lake cores (MEN1=7,689 and H1=8,440 cal yrs BP) and surface deposits (MEN1=7,471 and H1=7,891 cal yrs BP), with the lake cores being somewhat older. H1 tephra layers range from 8 to 18 cm thick, suggesting that both the area of the 10 cm isopach and the volume of this eruption were larger than previously suggested, but not greatly, and that the direction of maximum dispersion was more to the south. MEN1 tephra layers range from 1-4 cm in thickness, indicating that this was probably a reasonably large (&gt;5 km3) eruption. Some of the lake cores also contain thin layers (&lt; 2 cm) of late Holocene H2 tephra and the recent H3 (1991 AD) tephra, both derived from the Hudson volcano. No tephra evidence has been observed for any late Pleistocene tephra, nor for the existence of the supposed Arenales volcano, proposed to be located west of Cochrane.</p

Puesta en marcha del curso on line “Envejecimiento y enfermedades neurodegenerativas” en la plataforma Miriadax

Este informe detalla los objetivos, actividades y métodos llevados a cabo durante la ejecución de un proyecto de innovación docente que tiene como objetivo implementar un curso online en abierto sobre las enfermedades neurodegenerativas y el envejecimiento

Chronic, intermittent treatment with a cannabinoid receptor agonist impairs recognition memory and brain network functional connectivity

Elucidating how cannabinoids affect brain function is instrumental for the development of therapeutic tools aiming to mitigate 'on target' side effects of cannabinoid based therapies. A single treatment with the cannabinoid receptor agonist, WIN 55,212-2, disrupts recognition memory in mice. Here we evaluate how prolonged, intermittent (30 days) exposure to WIN 55,212-2 (1mg/kg) alters recognition memory and impacts on brain metabolism and functional connectivity. We show that chronic, intermittent treatment with WIN 55,212-2 disrupts recognition memory (Novel Object Recognition Test) without affecting locomotion and anxiety-like behaviour (Open Field and Elevated Plus Maze). Through 14 C-2-deoxyglucose functional brain imaging we show that chronic, intermittent WIN 55,212-2 exposure induces hypometabolism in the hippocampal dorsal subiculum and in the mediodorsal nucleus of the thalamus, two brain regions directly involved in recognition memory. In addition, WIN 55,212-2 exposure induces hypometabolism in the habenula with a contrasting hypermetabolism in the globus pallidus. Through the application of the Partial Least Squares Regression (PLSR) algorithm to the brain imaging data, we observed that prolonged WIN 55,212-2 administration alters functional connectivity in brain networks that underlie recognition memory, including that between the hippocampus and prefrontal cortex, the thalamus and prefrontal cortex, and between the hippocampus and the perirhinal cortex. In addition, our results support disturbed lateral habenula and serotonin system functional connectivity following WIN 55,212-2 exposure. Overall, this study provides new insight into the functional mechanisms underlying the impact of chronic cannabinoid exposure on memory and highlights the serotonin system as a particularly vulnerable target. This article is protected by copyright. All rights reserved

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Glacier fluctuations in the northern Patagonian Andes (44°S) imply wind-modulated interhemispheric in-phase climate shifts during Termination 1

The Last Glacial Termination (T1) featured major changes in global circulation systems that led to a shift from glacial to interglacial climate. While polar ice cores attest to an antiphased thermal pattern at millennial timescales, recent well-dated moraine records from both hemispheres suggest in-phase fluctuations in glaciers through T1, which is inconsistent with the bipolar see-saw paradigm. Here, we present a glacier chronology based on 30 new 10Be surface exposure ages from well-preserved moraines in the Lago Palena/General Vintter basin in northern Patagonia (~ 44°S). We find that the main glacier lobe underwent profound retreat after 19.7 ± 0.7 ka. This recessional trend led to the individualization of the Cerro Riñón glacier by ~ 16.3 ka, which underwent minor readvances at 15.9 ± 0.5 ka during Heinrich Stadial 1, during the Antarctic Cold Reversal with successive maxima at 13.5 ± 0.4, 13.1 ± 0.4, and 13.1 ± 0.5 ka, and a minor culmination at 12.5 ± 0.4 ka during Younger Dryas time. We conclude that fluctuations of Patagonian glaciers during T1 were controlled primarily by climate anomalies brought by shifts in the Southern Westerly Winds (SWW) locus. We posit that the global covariation of mountain glaciers during T1 was linked to variations in atmospheric CO2 (atmCO2) promoted by the interplay of the SWW-Southern Ocean system at millennial timescales.Fil: Soteres, Rodrigo L.. Universidad Católica de Chile; Chile. Pontificia Universidad Católica de Chile; ChileFil: Sagredo, Esteban A.. Pontificia Universidad Católica de Chile; Chile. Universidad Católica de Chile; ChileFil: Kaplan, Michael R.. Columbia University; Estados UnidosFil: Martini, Mateo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentina. Pontificia Universidad Católica de Chile; ChileFil: Moreno, Patricio I.. Universidad de Chile; ChileFil: Reynhout, Scott A.. Universidad de Chile; ChileFil: Schwartz, Roseanne. Columbia University; Estados UnidosFil: Schaefer, Joerg M.. Columbia University; Estados Unido

Cosmogenic nuclide moraine chronologies from Patagonia: A globally synchronic response of mountain glaciers during Termination 1?

Surface-exposure dating of moraines reveals that Patagonian glaciers fluctuated at the pulsebeat mimicked in polar ice cores from both hemispheres. These findings favor hypotheses that invoke coupled oceanic–atmospheric drivers to generate and propagate millennial-scale climate shifts during Termination 1.Fil: Soteres, Rodrigo L.. Universidad de Magallanes; ChileFil: Sagredo, Esteban. Pontificia Universidad Católica de Chile; Chile. Estación de Investigaciones Multidisciplinares Patagonia; ChileFil: Kaplan, M.R.. Columbia University; Estados UnidosFil: Martini, Mateo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Riquelme, Fabian. Pontificia Universidad Católica de Chile; ChileFil: Schaefer, J.M.. Columbia University; Estados Unido

The last millennium viewed from a fine-resolution freshwater diatom record from northwestern Patagonia

Little is known about the response of terrestrial and aquatic ecosystems to changes in climatic and human influences during the last millennium in northwestern Patagonia (NWP, 40°-44°S). By virtue of their sensitivity and specificity, diatoms are ideal for examining past changes in aquatic ecosystems and deciphering the ranges of variability under natural and human-induced conditions. To date, however, very few fossils diatom studies have examined in detail the environmental evolution during the last millennium throughout Patagonia. Here we present a fine-resolution diatom record from a lake-sediment core collected from Lago Pichilaguna (41°S), a closed-basin and shallow lake with a small catchment area located in the lowlands of the Chilean Lake District in NWP. The record spans the last millennium with a median time resolution of ∼12 years between samples, and shows abundant small Aulacoseira spp. between ∼1000-900 and ∼600-300 cal yr BP, which alternate in dominance with small fragilarioids and small raphid diatoms between ∼900-600 and ∼300-200 cal yr BP. A rapid shift to planktonic diatoms started at ∼200 cal yr BP and led to their modern dominance. We interpret centennial-scale changes in temperature, precipitation, and lake turbulence, with warm/dry/stratified phases between ∼1000-900 and ∼600-300 cal yr BP related to weak westerly winds, and intervals of cold/wet and mixed water column conditions between ∼900-600 and ∼300-200 cal yr BP, favored by stronger winds. The transition from periphytic to planktonic diatoms that started at ∼200 cal yr BP suggests juxtaposition of the warmest/driest phase of the last millennium and the onset of large-scale disturbance by Chilean/European settlers in NWP. Our results reveal that human disturbance during historical time surpassed the natural ranges of variability and resilience of aquatic and terrestrial ecosystems over the last millennium, generating abrupt changes in biodiversity, species composition, and community structure.Fil: Sepulveda Zunñiga, Einer. Pontificia Universidad Católica de Chile; ChileFil: Maidana, Nora Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Villacis, Leonardo. Universidad de Chile; ChileFil: Sagredo, Esteban A.. Pontificia Universidad Católica de Chile; ChileFil: Moreno, Patricio I.. Universidad de Chile; Chil