Omnidirectional flat bands in chiral magnonic crystals

The magnonic band structure of two-dimensional chiral magnonic crystals is theoretically investigated. The proposed metamaterial involves a three-dimensional architecture, where a thin ferromagnetic layer is in contact with a two-dimensional periodic array of heavy-metal square islands. When these two materials are in contact, an anti-symmetric exchange coupling known as the Dzyaloshinskii–Moriya interaction (DMI) arises, which generates nonreciprocal spin waves and chiral magnetic order. The Landau–Lifshitz equation and the plane-wave method are employed to study the dynamic magnetic behavior. A systematic variation of geometric parameters, the DMI constant, and the filling fraction allows the examination of spin-wave propagation features, such as the spatial profiles of the dynamic magnetization, the isofrequency contours, and group velocities. In this study, it is found that omnidirectional flat magnonic bands are induced by a sufficiently strong Dzyaloshinskii–Moriya interaction underneath the heavy-metal islands, where the spin excitations are active. The theoretical results were substantiated by micromagnetic simulations. These findings are relevant for envisioning applications associated with spin-wave-based logic devices, where the nonreciprocity and channeling of the spin waves are of fundamental and practical scientific interest

Escucha México, Estrategias gráficas y cultura auditiva. Primavera 2022

Durante Primavera 2022, el equipo de PAP Escucha México trabajó en diferentes proyectos con el objetivo de crear conciencia y sensibilizar sobre temáticas relacionadas a la cultura y discapacidad auditiva y el ruido excesivo en Guadalajara. A través de diferentes fuentes y medios de apoyo logramos transmitir la problemática a la comunidad, esto con el propósito de crecer el conocimiento que se tiene de la cultura auditiva. Los proyectos individuales que participan dentro del PAP son Cruzada Contra el Ruido, Clínica Mariana Anaya Doll, Iniciativa México Cubrebocas Transparente, Brankia, redes sociales del PAP Escucha México, Universidad Incluyente ITESO y la planeación del 4to Encuentro Internacional de Cultura Auditiva.Cada uno de estos se enfoca en temáticas diferentes sin embargo todos engloban las mencionadas al inicio.ITESO, A.C

Miradas desde la historia social y la historia intelectual: América Latina en sus culturas: de los procesos independistas a la globalización

Fil: Benito Moya, Silvano G. A. Universidad Católica de Córdoba. Facultad de Filosofía y Humanidades; Argentina.Fil: Universidad Católica de Córdoba. Facultad de Filosofía y Humanidades; Argentina

Omnidirectional flat bands in chiral magnonic crystals

The magnonic band structure of two-dimensional chiral magnonic crystals is theoretically investigated. The proposed metamaterial involves a three-dimensional architecture, where a thin ferromagnetic layer is in contact with a two-dimensional periodic array of heavy-metal square islands. When these two materials are in contact, an anti-symmetric exchange coupling known as the Dzyaloshinskii–Moriya interaction (DMI) arises, which generates nonreciprocal spin waves and chiral magnetic order. The Landau–Lifshitz equation and the plane-wave method are employed to study the dynamic magnetic behavior. A systematic variation of geometric parameters, the DMI constant, and the filling fraction allows the examination of spin-wave propagation features, such as the spatial profiles of the dynamic magnetization, the isofrequency contours, and group velocities. In this study, it is found that omnidirectional flat magnonic bands are induced by a sufficiently strong Dzyaloshinskii–Moriya interaction underneath the heavy-metal islands, where the spin excitations are active. The theoretical results were substantiated by micromagnetic simulations. These findings are relevant for envisioning applications associated with spin-wave-based logic devices, where the nonreciprocity and channeling of the spin waves are of fundamental and practical scientific interest

Uso de microorganismos antárticos como estrategia para mitigar los efectos del estrés salino en Lactuca sativa L. bajo un escenario futuro de cambio climático

47 p.El cambio climático es un fenómeno que se ha vuelto una problemática a nivel mundial, afectando diversos ámbitos, especialmente la agricultura. En Chile, su proyección augura una influencia negativa en algunos factores, en los que destaca, la menor disponibilidad del recurso hídrico (menores precipitaciones), el aumento de la temperatura, la desertificación y la salinización de suelos de uso agrícola. Es por esto que se hace imperativo la búsqueda de herramientas y estrategias para mitigar algunos de estos factores. Un factor potenciado por el cambio climático es la salinidad de los suelos, factor importante en los sistemas agrícolas, dado su efecto negativo en la mayoría de las plantas cultivadas en el país. La salinidad afecta el crecimiento y desarrollo de los cultivos principalmente por toxicidad iónica, desbalance nutricional, disminución del potencial hídrico del suelo y aumento de especies de oxígeno radioactivas (ROS) en las plantas. Las medidas para palear los efectos de la salinidad de suelos resultan la mayoría de las veces poco viables, por los altos costos y por los altos volúmenes de aplicación para mejorar las características de los suelos (sulfato de Ca, zeolita o lavado de suelos). Para la región del Maule se estima un aumento del nivel de salinidad hasta de tres veces en los próximos 50 años, esto, es decir, de 50mM a 150Mm. Uno de los cultivos de hoja más afectados sin duda será la lechuga, hortaliza más importante a nivel mundial, la cual es muy sensible a la salinidad. Una estrategia alternativa para combatir el efecto de la salinidad en cultivos agrícolas es el uso de microorganismos antárticos asociados a vegetales (hongos y bacterias) los cuales por condiciones naturales pueden desarrollarse en escenarios de salinidad (zonas costeras de islas del continente antártico). Es por ello que el presente estudio se basa en la inoculación de microorganismos antárticos sobre el cultivo de lechuga (Lactuca sativa), en condiciones de salinidad (200mM) con el fin de evaluar el desempeño productivo, fisiológico y el rol osmoprotector que pueden conferir estos microorganismos a los cultivos frente a la proyección del cambio climático para Chile y la región del Maule. Palabras claves: Cambio climático, salinidad, microrganismos antárticos/ABSTRACT:Climate change is a phenomenon that has become a problem worldwide, affecting several areas, especially agriculture. In Chile, its projection predicts a negative influence on some factors, which include a lower availability of water resources (lower rainfall), an increase in temperature, desertification and salinization of agricultural land. Thus, it is imperative to search any tools and/or strategies to mitigate some of these factors. A component enhanced by climate change is soil salinity, an important factor limiting the agricultural systems, given its negative effect on most of the plants grown and yield worlwide. Salinity affects the growth and development of crops mainly due to ionic toxicity, nutritional imbalance, decrease in soil water potential and increase of radioactive oxygen species (ROS) in plants. For the Maule region, an increase in the salinity level is estimated up to three times in the next 50 years, that is, from 50mM to 150Mm. One of the most affected leaf crops will undoubtedly be the lettuce crop, the most important vegetable in the world, which is very sensitive to salinity. An alternative strategy to combat the effect of salinity in agricultural crops is the use of antarctic root-microorganisms associated with plants (fungi and bacteria) which by natural selection can develop under salinity conditions (coastal areas of islands of the Antarctic continent). The present study evaluated, based in the inoculation of Antarctic microorganisms on lettuce (Lactuca sativa), the ecophysiological performance and yield of this crop under salinity conditions. Specifically, was assessed the productive, physiological, gene expression and osmoprotective role that can confer these microorganisms in front of the projection of climate change for the Maule region. Keywords: Climate change, salinity, Antarctic microorganisms

Antioxidant Therapeutic Strategies for Cardiovascular Conditions Associated with Oxidative Stress

Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability to scavenge these ROS by endogenous antioxidant systems, where ROS overwhelms the antioxidant capacity. Excessive presence of ROS results in irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Oxidative stress plays a crucial role in the pathogenesis of cardiovascular diseases related to hypoxia, cardiotoxicity and ischemia–reperfusion. Here, we describe the participation of OS in the pathophysiology of cardiovascular conditions such as myocardial infarction, anthracycline cardiotoxicity and congenital heart disease. This review focuses on the different clinical events where redox factors and OS are related to cardiovascular pathophysiology, giving to support for novel pharmacological therapies such as omega 3 fatty acids, non-selective betablockers and microRNAs

Bacterial community structure in a sympagic habitat expanding with global warming: brackish ice brine at 85–90 °N

© 2018, International Society for Microbial Ecology.Larger volumes of sea ice have been thawing in the Central Arctic Ocean (CAO) during the last decades than during the past 800,000 years. Brackish brine (fed by meltwater inside the ice) is an expanding sympagic habitat in summer all over the CAO. We report for the first time the structure of bacterial communities in this brine. They are composed of psychrophilic extremophiles, many of them related to phylotypes known from Arctic and Antarctic regions. Community structure displayed strong habitat segregation between brackish ice brine (IB; salinity 2.4–9.6) and immediate sub-ice seawater (SW; salinity 33.3–34.9), expressed at all taxonomic levels (class to genus), by dominant phylotypes as well as by the rare biosphere, and with specialists dominating IB and generalists SW. The dominant phylotypes in IB were related to Candidatus Aquiluna and Flavobacterium, those in SW to Balneatrix and ZD0405, and those shared between the habitats