Examinando por Autor "Jorquera, J."

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    Black carbon footprint of human presence in Antarctica
    (Nature Research, 2022-03) Cordero, R.; Sepúlveda, E.; Feron, S.; Damiani, A.; Fernandoy, F.; Neshyba, S.; Rowe, P.; Asencio, V.; Carrasco, J.; Alfonso, J.; Llanillo, P.; Wachter, P.; Seckmeyer, G.; Stepanova, M.; Carrera, J.; Jorquera, J.; Wang, Ch.; Malhotra, A.; Dana, J.; Khan, A.; Casassa, G.
    Black carbon (BC) from fossil fuel and biomass combustion darkens the snow and makes it melt sooner. The BC footprint of research activities and tourism in Antarctica has likely increased as human presence in the continent has surged in recent decades. Here, we report on measurements of the BC concentration in snow samples from 28 sites across a transect of about 2,000 km from the northern tip of Antarctica (62°S) to the southern Ellsworth Mountains (79°S). Our surveys show that BC content in snow surrounding research facilities and popular shore tourist-landing sites is considerably above background levels measured elsewhere in the continent. The resulting radiative forcing is accelerating snow melting and shrinking the snowpack on BC-impacted areas on the Antarctic Peninsula and associated archipelagos by up to 23 mm water equivalent (w.e.) every summer.
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    Opciones de tratamiento para la apnea obstructiva del sueño leve y moderadaTreatment options for mild and moderate obstructive sleep apnea
    (Clínica Las Condes, 2024-08) Jorquera, J.; Salas-Cossio, C.; Oyarzo, J.; Pacheco, C.; Del Favero, M.; Sánchez, M.
    La apnea obstructiva del sueño (AOS) es una enfermedad frecuente que produce síntomas diurnos, deterioro en la calidad de vida, mayor riesgo de morbi-mortalidad cardio y cerebrovascular, deterioro neuro cognitivo y mayor accidentabilidad de tránsito. La terapia con presión positiva continua en la vía aérea (CPAP) es altamente eficaz y ha sido el tratamiento de elección en los pacientes con enfermedad grave y aquellos con enfermedad moderada con síntomas diurnos y/o comorbilidad cardiovascular, sin embargo, la CPAP tiene limitaciones en términos de aceptación y adherencia al tratamiento. Existen diversas opciones de tratamiento, como la pérdida de peso, el uso de dispositivos orales, medidas posturales, cirugía y la terapia miofuncional. Estos tratamientos personalizados han demostrado buenos resultados, especialmente en pacientes con AOS leve a moderada o en aquellos que buscan alternativas efectivas al tratamiento convencional. Se reconoce cada vez más que la AOS es un trastorno multifactorial con diversas presentaciones clínicas, fisiopatología y comorbilidades. Una mejor comprensión de la heterogeneidad de los pacientes permitirá enfoques de tratamiento más personalizados y garantizará la efectividad de las intervenciones mediante una medicina avanzada y de precisión. Esta revisión proporciona una descripción de los enfoques actuales para el tratamiento no quirúrgico de la AOS leve a moderada en pacientes sin indicación de tratamiento con CPAP o que rechazan dicha opción, además de proponer un algoritmo terapéutico para orientar el manejo de estos pacientes.
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    Persistent extreme ultraviolet irradiance in Antarctica despite the ozone recovery onset
    (Nature Research, 2022-01) Cordero, R.; Feron, S.; Damiani, A.; Redondas, A.; Carrasco, J.; Sepúlveda, E.; Jorquera, J.; Fernandoy, F.; Llanillo, P.; Rowe, P.; Seckmeyer, G.
    Attributable to the Montreal Protocol, the most successful environmental treaty ever, human-made ozone-depleting substances are declining and the stratospheric Antarctic ozone layer is recovering. However, the Antarctic ozone hole continues to occur every year, with the severity of ozone loss strongly modulated by meteorological conditions. In late November and early December 2020, we measured at the northern tip of the Antarctic Peninsula the highest ultraviolet (UV) irradiances recorded in the Antarctic continent in more than two decades. On Dec. 2nd, the noon-time UV index on King George Island peaked at 14.3, very close to the largest UV index ever recorded in the continent. On Dec. 3rd, the erythemal daily dose at the same site was among the highest on Earth, only comparable to those recorded at high altitude sites in the Atacama Desert, near the Tropic of Capricorn. Here we show that, despite the Antarctic ozone recovery observed in early spring, the conditions that favor these extreme surface UV events persist in late spring, when the biologically effective UV radiation is more consequential. These conditions include long-lasting ozone holes (attributable to the polar vortex dynamics) that often bring ozone-depleted air over the Antarctic Peninsula in late spring. The fact that these conditions have been occurring at about the same frequency during the last two decades explains the persistence of extreme surface UV events in Antarctica.