Response of alluvial systems to Late Pleistocene climate changes recorded by environmental magnetism in the Añavieja Basin (Iberian Range, NE Spain)

Environmental magnetic proxies were analyzed in a relatively monotonous, ~25.3m thick alluvial sedimentary sequence drilled in the Añavieja Basin (NE Spain). Results from the core AÑ2 suggest that the concentrationdependent magnetic parameters mainly reflect variations in the content of detrital magnetite, sourced in the catchment rocks and soils of the basin, via changes in the dynamics of alluvial fans due to temperature changes in the northern hemisphere during the Late Pleistocene. The correspondence between the magnetic proxies and the temperature variations in the North Atlantic region (NGRIP curve) indicates that higher (lower) concentrations and finer (coarser) magnetite grains coincide with warm (cold) periods. We propose that during cold periods, a sparser vegetation cover favored the incoming of higher energy runoff bearing coarser sediments to the basin that are relatively impoverished in magnetite. In contrast, during warm periods, the wider distribution of the vegetation cover associated with the lower runoff energy lead to finer, magnetite-richer sediment input to the basin. Maghemite, presumably of pedogenic origin, appears to be present also in the studied alluvial sediments. Further studies are necessary to unravel its palaeoclimatic significance

Células presentadoras de antígeno: células dendríticas y su papel en la lengua azul

Las células presentadoras de antígeno (CPA) desempeñan un papel fundamental en el desarrollo de la respuesta inmunitaria mediante el procesamiento y la presentación de antígenos, así como a través de distintos estímulos que favorecen la proliferación y diferenciación linfocitaria. Entre las CPA, las células dendríticas (CDs) son consideradas como las más eficientes en las funciones de presentación. En este trabajo se abordan aspectos generales relacionados con la localización, estructura y función de estas células, así como con su importante papel en la instauración de la repuesta inmunitaria. Junto a las células endoteliales y a los macrófagos, las CDs son consideradas células blanco del virus de la lengua azul (vLA), desempeñando un importante papel en la diseminación orgánica de éste. Además, las CDs parecen jugar un importante papel como productoras o inductoras de sustancias vasoactivas responsables de los cambios vasculares que caracterizan a la enfermedad, quedando aún por determinar la influencia de estos mediadores químicos en la instauración de la respuesta inmunológica frente al virus, aspecto fundamental para el desarrollo y mejora de vacunas

Response of alluvial systems to Late Pleistocene climate changes recorded by environmental magnetism in the Añavieja Basin (Iberian Range, NE Spain)

Environmental magnetic proxies were analyzed in a relatively monotonous, ~25.3m thick alluvial sedimentary sequence drilled in the Añavieja Basin (NE Spain). Results from the core AÑ2 suggest that the concentrationdependent magnetic parameters mainly reflect variations in the content of detrital magnetite, sourced in the catchment rocks and soils of the basin, via changes in the dynamics of alluvial fans due to temperature changes in the northern hemisphere during the Late Pleistocene. The correspondence between the magnetic proxies and the temperature variations in the North Atlantic region (NGRIP curve) indicates that higher (lower) concentrations and finer (coarser) magnetite grains coincide with warm (cold) periods. We propose that during cold periods, a sparser vegetation cover favored the incoming of higher energy runoff bearing coarser sediments to the basin that are relatively impoverished in magnetite. In contrast, during warm periods, the wider distribution of the vegetation cover associated with the lower runoff energy lead to finer, magnetite-richer sediment input to the basin. Maghemite, presumably of pedogenic origin, appears to be present also in the studied alluvial sediments. Further studies are necessary to unravel its palaeoclimatic significance

Desarrollo de germoplasma de maíz para suelos ácidos: programa suramericano de maíz CIMMYT.

La baja fertilidad de los uselos es el problema más importante en la reducción de los rendimiento de maíz en los tropicos y la acidez del suelo es el principal causante de esta baja fertilidad, siendo la toxicidad de aluminio la principal causa. Actualmente se seimbran entre 8 y 29 millones de ha. de maíz en suelos ácidos con bajo pH, alta concentración de Al, y deficiencia en Ca, Mg y P. En los suelos ácidos se inhibe el crecimiento radicular que finalmente se manifiesta en una dismimunción del rendimiento. El CIMMYT, en colaboración con los Programas Nacionales, esta aprovechando la gran variabilidad en el maíz para generar cultivares que puedan crecer bajo el estress provocado por la ácidez del suelo y que su cultivo sea una actividad económicamente viable y que no interfiera con la sosteniblidad del ambiente. Estudios realizados en Colombia y otros lugares indican que la selección recurrente recíproca, basada en el comportamiento de genotivos a través de un rango de ambiente será efectiva en el desarrollo de variedades e híbridos tolerantes. La capacidad de rendimiento en suelos ácidos esta correlacionada positivamente con el comportamiento en suelos fértiles no ácidos. Por esta razón, los cultivadores de maíz tolerantes a la acidez pueden crecer y produciir bien tanto en suelos ácidos en no ácidos. Como resultado de este proyecto colaborativo se han liberado dos cultivares de maíz: Sikuani ICA V110-Colombia y Antasena en Indonesia, actualmente en evaluación en diferentes países Estudios agronómicos indican la superioridad de los cultivares tolerantes con relación a los susceptibles o comerciales en un rango de suelos ácidos y no ácidosMaíz-Zea may

Flipped Classroom educational innovation experience in a Master in Energy Engineering subject

En este trabajo se describe la experiencia de innovación llevada a cabo en la asignatura de Exergía, Termoeconomía y Cogeneración del Máster Universitario en Ingeniería Energética de la Universidad de Oviedo durante el curso 2019/2020. Los resultados de aprendizaje mostraban que parte del potencial del estudiantado se encontraba desaprovechado, por lo que se detectó la necesidad de conseguir un mejor aprovechamiento de las clases presenciales. Con este objetivo, se desarrolló un Proyecto de Innovación Docente basado en una metodología de aula invertida y de aprendizaje colaborativo, en el que los alumnos preparaban una serie de contenidos antes de acudir al aula para luego trabajar de forma colaborativa en la misma. Con dicho Proyecto, se ha conseguido mejorar sustancialmente los resultados de aprendizaje, así como lograr un mayor grado de satisfacción del estudiantado respecto a la asignatura y la metodología docente empleada. Las interacciones en el aula han mejorado notablemente y la confianza de los estudiantes en sí mismos y su conocimiento se ha reforzado. Finalmente, se recoge una autoevaluación de la mejora implementada, así como posibles propuestas para el futuro. La principal es la continuación de la mejora en el curso siguiente para poder evaluar su consolidación.This work describes the innovation experience performed in the subject Exergy, Thermoeconomy and Cogeneration of the Master in Energy Engineering of the University of Oviedo during the year 2019/2020. After reviewing the learning results of the students and realizing that part of their potential was being lost, the necessity of improving the time management in the classroom was identified. With this aim, a Teaching Innovation Project based on a flipped classroom and collaborative learning methodology was developed, in which the students prepared a series of contents at home, before coming to class, to work collaboratively afterwards in the classroom. With this Project, the learning results have been substantially improved. Additionally, the students feel more satisfied about the subject and the teaching methodology employed. The classroom interactions have noticeably improved and the self-confidence of students on themselves and their knowledge has been reinforced. Finally, a self-assessment of the implemented improvement has been performed and future proposals have been outlined. The main proposal is to continue the implemented improvement next term to evaluate its consolidation

Application of the finite-temperature Lanczos method for the evaluation of magnetocaloric properties of large magnetic molecules

We discuss the magnetocaloric properties of gadolinium containing magnetic molecules which potentially could be used for sub-Kelvin cooling. We show that a degeneracy of a singlet ground state could be advantageous in order to support adiabatic processes to low temperatures and simultaneously minimize disturbing dipolar interactions. Since the Hilbert spaces of such spin systems assume very large dimensions we evaluate the necessary thermodynamic observables by means of the Finite-Temperature Lanczos Method.Comment: 7 pages, 10 figures, invited for the special issue of EPJB on "New trends in magnetism and magnetic materials

Frequency behavior of Raman coupling coefficient in glasses

Low-frequency Raman coupling coefficient of 11 different glasses is evaluated. It is found that the coupling coefficient demonstrates a universal linear frequency behavior near the boson peak maximum and a superlinear behavior at very low frequencies. The last observation suggests vanishing of the coupling coefficient when frequency tends to zero. The results are discussed in terms of the vibration wavefunction that combines features of localized and extended modes.Comment: 8 pages, 9 figure

Two-body Z′Z' decays in the minimal 331 model

The two-body decays of the extra neutral boson Z_2 predicted by the minimal 331 model are analyzed. At the three-level it can decay into standard model particles as well as exotic quarks and the new gauge bosons predicted by the model. The decays into a lepton pair are strongly suppressed, with $Br(Z_2 --> l^+l^-) ~ 10^{-2}$ and $Br(Z_2 --> \bar{\nu}_l \nu) ~ 10^{-3}$. In the bosonic sector, Z_2 would decay mainly into a pair of bilepton gauge bosons, with a branching ratio below the 0.1 level. The Z_2 boson has thus a leptophobic and bileptophobic nature and it would decay dominantly into quark pairs. The anomaly-induced decays $Z_2 --> Z_1\gamma$ and $Z_2 --> Z_1Z_1$, which occurs at the one-loop level are studied. It is found that $Br(Z_2 --> Z_1\gamma) ~ 10^{-9}$ and $Br(Z_2 --> Z_1Z_1) ~ 10^{-6}$ at most. As for the $Z_2 --> W^+W^-$ and $Z_2 --> Z_1H$ decays, with H a relatively light Higgs boson, they are induced via Z'-Z mixing. It is obtained that $Br(Z_2 --> W^+W^-) ~ 10^{-2}$ and $Br (Z_2 --> Z_1H) ~ 10^{-5}$. We also examine the flavor changing neutral current decays $Z_2 --> tc$ and $Z_2 --> tu$, which may have branching fractions as large as $10^{-3}$ and $10^{-5}$, respectively, and thus may be of phenomenological interest.Comment: 14 pages, 3 figures, submitted to Physical Review

Pre-M Phase-promoting Factor Associates with Annulate Lamellae in Xenopus Oocytes and Egg Extracts

We have used complementary biochemical and in vivo approaches to study the compartmentalization of M phase-promoting factor (MPF) in prophase Xenopus eggs and oocytes. We first examined the distribution of MPF (Cdc2/CyclinB2) and membranous organelles in high-speed extracts of Xenopus eggs made during mitotic prophase. These extracts were found to lack mitochondria, Golgi membranes, and most endoplasmic reticulum (ER) but to contain the bulk of the pre-MPF pool. This pre-MPF could be pelleted by further centrifugation along with components necessary to activate it. On activation, Cdc2/CyclinB2 moved into the soluble fraction. Electron microscopy and Western blot analysis showed that the pre-MPF pellet contained a specific ER subdomain comprising "annulate lamellae" (AL): stacked ER membranes highly enriched in nuclear pores. Colocalization of pre-MPF with AL was demonstrated by anti-CyclinB2 immunofluorescence in prophase oocytes, in which AL are positioned close to the vegetal surface. Green fluorescent protein-CyclinB2 expressed in oocytes also localized at AL. These data suggest that inactive MPF associates with nuclear envelope components just before activation. This association may explain why nuclei and centrosomes stimulate MPF activation and provide a mechanism for targeting of MPF to some of its key substrates

High-contrast imaging constraints on gas giant planet formation - The Herbig Ae/Be star opportunity

Planet formation studies are often focused on solar-type stars, implicitly considering our Sun as reference point. This approach overlooks, however, that Herbig Ae/Be stars are in some sense much better targets to study planet formation processes empirically, with their disks generally being larger, brighter and simply easier to observe across a large wavelength range. In addition, massive gas giant planets have been found on wide orbits around early type stars, triggering the question if these objects did indeed form there and, if so, by what process. In the following I briefly review what we currently know about the occurrence rate of planets around intermediate mass stars, before discussing recent results from Herbig Ae/Be stars in the context of planet formation. The main emphasis is put on spatially resolved polarized light images of potentially planet forming disks and how these images - in combination with other data - can be used to empirically constrain (parts of) the planet formation process. Of particular interest are two objects, HD100546 and HD169142, where, in addition to intriguing morphological structures in the disks, direct observational evidence for (very) young planets has been reported. I conclude with an outlook, what further progress we can expect in the very near future with the next generation of high-contrast imagers at 8-m class telescopes and their synergies with ALMA.Comment: Accepted by Astrophysics and Space Science as invited short review in special issue about Herbig Ae/Be stars; 12 pages incl. 5 figures, 2 tables and reference