17 research outputs found

    Crystallization conditions and petrogenetic characterization of metaluminous to peraluminous calc-alkaline orogenic granitoids from mineralogical systematics: the case of the Cambrian magmatism from the Sierra de Guasayán (Argentina)

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    The Sierra de Guasayán (Eastern Sierras Pampeanas, Argentina) is formed by low to medium grade metamorphic rocks intruded by Cambrian metaluminous (La Soledad quartz-diorite), slightly peraluminous (Guasayán, El Escondido and El Martirizado granodiorite plutons), and strongly peraluminous (Alto Bello granodiorite) granitoids of the Pampean magmatic arc. Chemical compositions of amphibole, plagioclase, biotite, and titanite indicate that these granitoids were emplaced at low pressure (mostly <3 kbar) and temperature (<770 °C) under oxidizing conditions (QFM + 1 and QFM + 2), which are similar to the emplacement conditions reported for other granites of the Pampean magmatic arc. Mineral assemblages and whole-rock and mineral chemistry of the granitoids from the Sierra de Guasayán indicate an I-type affinity for the La Soledad quartz-diorite (amphibole, biotite, and titanite), S-type affinity for the Alto Bello granodiorite (biotite, muscovite, cordierite, and sillimanite), and a hybrid nature for the main Guasayán and El Escondido plutons (biotite, monazite, and magnetite). This hybrid nature is supported by the presence of abundant mafic microgranular enclaves and rapakivi texture and by published zircon Hf-isotope data (εHfi ranging from −4.76 to −0.12). This suggests, in turn, the involvement of hybridization in the genesis of these granitoids, which seems to be a common mechanism operating in the Pampean magmatic arc.Instituto de Recursos Minerale

    Spread of a SARS-CoV-2 variant through Europe in the summer of 2020

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    [EN] Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3,4,5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant’s success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes.S

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Estrategias pedagógicas implementadas alrededor de la participación infantil durante la pandemia por Covid-19

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    The following article presents the results of a research project with the purpose of making known the pedagogical strategies implemented by a teacher around child participation during the Covid-19 pandemic and how these strategies contribute to participatory processes of children in different contexts, whether educational or social. This research was carried out with a population of 25 children from 4 to 5 years of age from the Kindergarten b grade and a teacher from the Hogar Infantil Tamborines in the municipality of Girardota, Antioquia. The results indicate that it is important in the application of these strategies to take into account the previous knowledge, skills, interest and need that is evident in the children in relation to the proposed topics, which in turn will develop and strengthen these learning processes in a meaningful way, facilitating the processes of socialization and integration in the different contexts where they interact and allowing them to face different difficulties that arise in the educational environment such as the challenges presented during the pandemic, which forced different sectors, especially the educational sector, to rethink these strategies with the intention of continuing these processes where the main beneficiaries are the children; This is why the role of the family and the school as facilitators in the acquisition of new knowledge must be taken into account.En el siguiente artículo se presentan los resultados de una investigación con el propósito de dar a conocer las estrategias pedagógicas que implementó una docente alrededor de la participación infantil durante la pandemia por Covid-19 y la manera en que esas estrategias contribuyen a procesos participativos de los niños y niñas en diferentes contextos ya sean educativos o sociales. Esta investigación se llevó a cabo con una población de 25 niños y niñas de 4 a 5 años de edad del grado Jardín b y una docente del Hogar Infantil Tamborines del municipio de Girardota, Antioquia. Que se realizó por medio del diseño cualitativo, con un enfoque hermenéutico, una modalidad biográfica narrativa, una estrategia de estudio de caso y unas técnicas de generación de información en donde se tiene la Técnica interactiva de Colcha de retazos y la entrevista semiestructurada. Los resultados indican que es importante en la aplicación de esas estrategias&nbsp; tener en cuenta, los conocimientos previos, las habilidades, el interés y la necesidad que se evidencia en los niños y niñas frente a las temáticas planteadas, que a su vez van desarrollando y afianzando esos aprendizajes de manera significativa, facilitando los procesos de socialización e integrarse en los diferentes contextos en que interactúan y que les permite enfrentarse a distintas dificultades que se presentan en el entorno educativo como los retos presentados&nbsp; durante la pandemia, que obligaron a diferentes sectores en especial a la educativa a replantearse&nbsp; en&nbsp; cuanto a esas estrategias con la intención de continuar&nbsp;&nbsp; estos procesos que tienen como principales beneficiarios a los niños y las niñas; es por esto que se debe tener encuenta el rol que cumple la familia y la escuela como facilitadores en la adquisición de nuevos conocimientos.&nbsp

    Exploring paleoproterozoic metamorphism in the western Río de la Plata craton from drill-core evidence

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    Rhyacian basement is not exposed in the western part of the Río de la Plata craton, but deep borehole samples (depth of 1046–3340 m) provide information on its composition and metamorphic evolution. An amphibole schist sample from the Camilo Aldao borehole underwent two metamorphic stages: M1 and M2. The P-T conditions of M1 are not constrained whereas the M2 main metamorphic stage is characterized by conditions of 6.1–7.4 kbar and 575–605 °C. In contrast, an olivine gabbronorite sample from the Santiago Temple borehole records crystallization conditions of 1.7 ± 0.6 kbar and 1180 ± 10 °C based on clinopyroxene composition, and late magmatic to subsolidus low-pressure granulite facies metamorphism at 2.3 ± 1.2 kbar and 749 ± 85 °C based on multi-equilibrium thermobarometry. The Rhyacian evolution of the Río de la Plata craton is characterized by at least three thermo-tectonic orogenic stages: T1 (ca. 2200–2100 Ma), T2 (ca. 2100–2040 Ma), and T3 (ca. 2040–2010 Ma) that correspond respectively to: 1) early oceanic subduction and juvenile continental arc magmatism; 2) subsequent continental collision (clockwise intermediate P/T paths of metamorphism), and 3) final low-pressure metamorphism coeval with post-orogenic magmatism. The Camilo Aldao amphibole schist is representative of the T2 orogenic stage while the Santiago Temple gabbronorite is representative of T3 magmatism and metamorphism.Ministerio de Economía y CompetitividadCONICETFondo para la Investigación Científica y TecnológicaDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu
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