Association between long-term air pollution exposure and COVID-19 mortality in Latin America

Recent studies have shown a relationship between air pollution and increased vulnerability and mortality due to COVID-19. Most of these studies have looked at developed countries. This study examines the relationship between long-term exposure to air pollution and COVID-19-related deaths in four countries of Latin America that have been highly affected by the pandemic: Brazil, Chile, Colombia, and Mexico. Our results suggest that an increase in long-term exposure of 1 μg/m3 of fine particles is associated with a 2.7 percent increase in the COVID-19 mortality rate. This relationship is found primarily in municipalities of metropolitan areas, where urban air pollution sources dominate, and air quality guidelines are usually exceeded. By focusing the analysis on Latin America, we provide a first glimpse on the role of air pollution as a risk factor for COVID-19 mortality within a context characterized by weak environmental institutions, limited health care capacity and high levels of inequality

Caracterización fisicoquímica de las aguas superficiales en la cuenca del Arroyo del Fuerte, Tandil

Fil: Cifuentes, M.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Humanas. Centro de Investigaciones y Estudios Ambientales; ArgentinaFil: Gabellone, Néstor A.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología Dr. Raúl Ringuelet; ArgentinaFil: Ruiz de Galarreta, Alejandro. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Humanas. Centro de Investigaciones y Estudios Ambientales; Argentin

Stratigraphy and chemostratigraphy of the Valanginian (pro parte) from Loma Solana, Sierra de Quípar (External Subbetic, Cehegín, Murcia)

The stratigraphy, biostratigraphy and geochemistry (C stable isotopes and RSTE trace elements) of a succession of Valanginian age outcropping in Loma Solana (External Subbetic) is presented. The succession is composed of two local sections, one cropping out to the west of Cehegín (Murcia) and another in the Garranchal gorge, to the SSW of this locality. The lithology consists of marl and marlstone rhythmically interbedded, which is typical of the Carretero Fm of the Subbetic. The ammonite zones and subzones of the middle- late early Valanginian and the complete late Valanginian, except for the lattermost part, have been identified, without any evidence of stratigraphic discontinuity between the two local sections. The δ13C curve show a similar shape to those of the same age obtained in other basins and the positive excursion of the δ13C characterizing the Weissert episode of environmental change (EECWeissert) has been identified. The RSTE, redox sensitive trace elements, analyzed do not show any particular increase as is typical of anoxic events and consequently conclude that anoxia due not exist in this part of the Subbetic basin during this EECSe presenta el estudio estratigráfico, bioestratigráfico y geoquímico de una sucesión del Valanginiense que aflora en Loma Solana (Subbético Externo). Se trata de una sección compuesta de dos secciones parciales, una de ellas levantada al oeste de Cehegín (Murcia) y la otra en el barranco del Garranchal, al SSO de dicha localidad. La litología,margas y margocalizas en alternancia rítmica, es la típica de la Fm. Carretero, a la que corresponde. Se identifican las zonas y subzonas de ammonites de la parte media-alta del Valanginiense inferior y de todo el Valanginiense superior, excepto la parte más terminal del mismo, sin que se haya denotado discontinuidad alguna entre una sección y otra. La curva de valores de δ13C muestra una forma similar a la obtenida en otras cuencas para la misma edad y en ella se puede identificar la excursión positiva del δ13C que caracteriza el episodioWeissert de cambio ambiental. Los elementos traza analizados, sensibles a cambios en las condiciones redox del medio sedimentario (elementos RSTE), no indican que hubiera condiciones anóxicas en el mismo durante este episodio de cambio ambienta

Meeting high precision requirements of additively manufactured components through hybrid manufacturing

A hybrid approach combining the laser powder bed fusion (LPBF) process and post-processing operations through 5-axis milling was employed to manufacture a Ti6Al4V aerospace component. From the design step, the requirements and needs in all the stages of the Hybrid Additive Manufacturing process were taken into account. A numerical simulation of distortions promoted by residual stresses during the additive process was employed to consider material allowance. The status of the as-built and post-processed component was analysed through scanning and CMM inspection and roughness measurements. The 3D scanned model of the as-built LPBF-ed component was used to understand the distortion behaviour of the component and compared to the numerical simulation. Finally, 5-axis milling operations were conducted in some critical surfaces in order to improve surface quality and dimensional accuracy of the as-built com- ponent. The inspection of the as-built and post-processed component showed the improvement achieved through the proposed hybrid approach. The work aims to provide the baselines needed to enable the metal Hybrid Additive Manufacturing of components with complex geometries where mandatory precision is required by integrating high accuracy machining operations as post-processing technique

Herramientas de software para dar soporte en la enseñanza y aprendizaje de la arquitectura x86

Existe un consenso creciente en el uso de herramientas de simulación en la enseñanza para procesos dinámicos complejos, como las operaciones intrínsecas de la computadora, que permiten representar de forma visual e interactiva la organización y arquitectura interna de la computadora, facilitando así la comprensión de su funcionamiento por parte de los alumnos y el desarrollo de los temas por parte del docente. En este contexto, los simuladores juegan una pieza clave en el campo de la Arquitectura de Computadoras, permitiendo conectar fundamentos teóricos con la experiencia práctica, simplificando abstracciones y haciendo más rica la labor docente. La arquitectura x86 es ampliamente utilizada en computadoras de escritorio y servidores. Este documento pretende realizar una comparación de los simuladores x86 que más se adecuan en el dictado de la asignatura Arquitectura de Computadoras de la carrera Licenciatura en Sistemas, establecer los criterios de evaluación y evaluar los simuladores seleccionados de acuerdo con estos criterios. La presente investigación surge en el marco del proyecto de investigación I/D novel PIDUNER 7065: “Enseñanza/aprendizaje de asignatura Arquitectura de Computadoras con herramientas de simulación de sistemas de cómputos”. El Proyecto es llevado a cabo en la Facultad de Ciencias de la Administración de la Universidad Nacional de Entre Ríos, se vincula directamente con la asignatura Arquitectura en Computadoras que se dicta en segundo año de la carrera Licenciatura en Sistemas perteneciente a la Facultad de Ciencias de la Administración de la Universidad Nacional de Entre Ríos.Red de Universidades con Carreras en Informátic

Effect of Nitrogen on Agronomic Yield, Spad Units and Nitrate Content in Roselle (Hibiscus Sabdariffal.) in Dry Weather

This study was conducted in polyethylene bags of 4 kg capacity with plants of Jamaica from seeds collected from an accession on the coast of Oaxaca, which were planted under the ecological conditions of Teotitlán de Flores Magón, and evaluated under completely randomized design, where treatments were four levels of nitrogen: 0, 50, 100 and 150 kg ha-1 and four repetitions (4x4) = 16 experimental units. The variables evaluated were: both agronomic yields: chalice and seed, harvest index, SPAD units and nitrate content in leaf. The results indicate that higher yields ofseed and chalice, biomass, nitrate content in leaf and SPAD units were achieved with the application of 100 kg ha-1 of nitrogen with 50.39, 196.80, 620.4 g plant-1, 85.00 mg kg-1 and 29.10 units, respectively. The content of nitrates and its relationship with SPAD units, adjusted to an increasing linear model for the four levels of nitrogen studied. From this study it can be concluded that the application of 100 kg N ha-1, positively affect the culture of Jamaica under dry weather conditions way

Magnetic and elastic anisotropy in magnetorheological elastomers using nickel-based nanoparticles and nanochains

Nickel (Ni) based nanoparticles and nanochains were incorporated as fillers in polydimethylsiloxane (PDMS) elastomers and then these mixtures were thermally cured in the presence of a uniform magnetic field. In this way, macroscopically structured-anisotropic PDMS-Ni based magnetorheological composites were obtained with the formation of pseudo-chains-like structures (referred as needles) oriented in the direction of the applied magnetic field when curing. Nanoparticles were synthesized at room temperature, under air ambient atmosphere (open air, atmospheric pressure) and then calcined at 400 °C (in air atmosphere also). The size distribution was obtained by fitting SAXS experiments with a polydisperse hard spheres model and a Schulz-Zimm distribution, obtaining a size distribution centered at (10.0 - 0.6) nm with polydispersivity given by sigma= (8.0 ± 0.2) nm. The SAXS, XRD and TEM experiments are consistent with single crystal nanoparticles of spherical shape (average particle diameter obtained by TEM: (12 ± 1) nm). Nickel-based nanochains (average diameter: 360 nm; average length: 3 mm, obtained by SEM; aspect ratio=length/diameter ~10) were obtained at 85 ºC and ambient atmosphere (open air, atmospheric pressure). The magnetic properties of Ni-based nanoparticles and nanochains at room temperature are compared and discussed in terms of surface and size effects. Both Ni-based nanoparticles and nanochains were used as fillers for obtaining the PDMS structured magnetorheological composites, observing the presence of oriented needles. Magnetization curves, ferromagnetic resonance spectra (FMR) and strain-stress curves of low filler´s loading composites (2% w/w of fillers) were determined as functions of the relative orientation respect to the needles. The results indicate that even at low loadings it is possible to obtain magnetorheological composites with anisotropic properties, with larger anisotropy when using nanochains. For instance, the magnetic remanence, the FMR-resonance field and the elastic response to compression are higher when measured parallel to the needles (about 30% with nanochains as fillers). Analogously, the elastic response is also anisotropic, with larger anisotropy when using nanochains as fillers. Therefore, all experiments performed confirm the high potential of nickel nanochains to induce anisotropic effects in magnetorheological materials.Fil: Landa, Romina Ailín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Química Física de los Materiales del Medioambiente y Energía; Argentina;Fil: P Soledad Antonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Química Física de los Materiales del Medioambiente y Energía; Argentina;Fil: Mariano M. Ruiz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Química Física de los Materiales del Medioambiente y Energía; Argentina;Fil: Oscar E Pérez. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Industrias;Fil: Alejandro Butera. Comisión Nacional de Energía Atómica;Fil: Guillermo Jorge. Universidad Nacional de General Sarmiento;Fil: Cristiano L. P. Oliveira. Instituto de Física, Universidade De São Paulo; Brasil;Fil: Martín Negri. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Industrias