87 research outputs found

    Multiferroic behavior in the new double-perovskite Lu2_2MnCoO6_6

    Full text link
    We present a new member of the multiferroic oxides, Lu2_2MnCoO6_6, which we have investigated using X-ray diffraction, neutron diffraction, specific heat, magnetization, electric polarization, and dielectric constant measurements. This material possesses an electric polarization strongly coupled to a net magnetization below 35 K, despite the antiferromagnetic ordering of the S=3/2S = 3/2 Mn4+^{4+} and Co2+^{2+} spins in an \uparrow \uparrow \downarrow \downarrow configuration along the c-direction. We discuss the magnetic order in terms of a condensation of domain boundaries between \uparrow \uparrow and \downarrow \downarrow ferromagnetic domains, with each domain boundary producing a net electric polarization due to spatial inversion symmetry breaking. In an applied magnetic field the domain boundaries slide, controlling the size of the net magnetization, electric polarization, and magnetoelectric coupling

    Discovery of Colossal Breathing-Caloric Effect under Low Applied Pressure in the Hybrid Organic–Inorganic MIL-53(Al) Material

    Get PDF
    Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] In this work, “breathing-caloric” effect is introduced as a new term to define very large thermal changes that arise from the combination of structural changes and gas adsorption processes occurring during breathing transitions. In regard to cooling and heating applications, this innovative caloric effect appears under very low working pressures and in a wide operating temperature range. This phenomenon, whose origin is analyzed in depth, is observed and reported here for the first time in the porous hybrid organic–inorganic MIL-53(Al) material. This MOF compound exhibits colossal thermal changes of ΔS ∼ 311 J K–1 kg–1 and ΔH ∼ 93 kJ kg–1 at room temperature (298 K) and under only 16 bar, pressure which is similar to that of common gas refrigerants at the same operating temperature (for instance, p(CO2) ∼ 64 bar and p(R134a) ∼ 6 bar) and noticeably lower than p > 1000 bar of most solid barocaloric materials. Furthermore, MIL-53(Al) can operate in a very wide temperature range from 333 K down to 254 K, matching the operating requirements of most HVAC systems. Therefore, these findings offer new eco-friendly alternatives to the current refrigeration systems that can be easily adapted to existing technologies and open the door to the innovation of future cooling systems yet to be developed.This work was financially supported by Ministerio de Economía y Competitividad MINECO and EU-FEDER (projects MAT2017-86453-R and PDC2021-121076-I00), Xunta de Galicia and IACOBUS Programme. Funding for open access fee was provided by Universidade da Coruña/CISU

    Posibilidades de la producción estacional de leche en Cuba en forma sostenible

    Get PDF
    Possibilities and potentialities of sustainable milk production in Cuba using current available resources for dairy cattle were studied. On this basis, the possibility to decrease the amount of imported dry whole milk to also decrease foreing currency investments and operational expenses in dairy farming systems, from dairy farms to dairy industry, was assessed. In Cuba, isolated herds have been studied, centering calvings at the initial and the intermediate periods during the rainy season. These calving patterns have had highly favorable responses in every production stage. Thus, an experiment was carried out at several commercial livestock areas including high potential females (7/8 Holstein x 1/8 Zebu) distributed into three groups according to calving pattern. In the first group, calvings occurred from April to May; in the second, from September to October, and in the third, from December to January. The first group produced more milk (7,9 kg milk/cow/day) than the other two. In addition, this group showed lower milk production costs, produced 2 256 kg milk/lactation, and had a 1,2 cow/ha total carrying capacity on Panicum maximun Jacq. and native legume grassland. Another important result in this commercial area (26 dairy farms distributed into 4 livestock dairy production centers) with most calving patterns (60-65%) centered at the beginning of the rainy season was an increase in 223 000 kg milk and a decrease in operational costs per dairy farm, some other analyses proved the bioeconomic advantages of a seasonal calving strategy oriented towards the rainy season, not only concerning commercial herds real cases, but simulations as well.Se estudiaron las posibilidades y potencialidades de la producción estacional de leche en Cuba, aprovechando los recursos de que dispone la ganadería. Sobre esa base se valoró la posibilidad de reducir los volúmenes de leche en polvo que se deben comprar en el exterior, para reducir la inversión de divisas y los gastos operacionales de los sistemas lecheros, desde la base agrícola hasta la industria. En Cuba se han estudiado rebaños aislados, concentrando los partos al inicio y mediados del período lluvioso; las respuestas bioeconómicas han sido muy favorables en toda la cadena productiva. Se desarrolló un experimento en áreas comerciales, con animales de alto potencial (7/8 Holstein1/8 Cebú), ubicados en tres grupos: uno parió en abril-mayo, otro en septiembre-octubre y el tercero en diciembreenero. El primer grupo produjo 7,9 kg por vaca diarios, superior a los restantes. Además, presentó menores costos de producción de leche y 2 256 kg por lactancia. La carga global fue de 1,2 vacas/ha en pastoreo de guinea (Panicum maximum, Jacq) y leguminosas nativas. Otro resultado importante para esta misma empresa (26 vaquerías en cuatro cooperativas) con patrones derivados en un 60 a 65 % hacia inicios de primavera, se demostró que en comparación con las restantes unidades, con ese patrón se incrementó la producción de leche en 223 000 kg y se lograron menores costos operacionales. Otros análisis demuestran la factibilidad bioeconómica de una estrategia estacional de pariciones hacia la lluvia, tanto en casos reales, como en simulaciones para rebaños comerciales

    Validity and reliability of a computer-assisted system method to measure axial vertebral rotation

    Get PDF
    BACKGROUND: Axial vertebral rotation and Cobb’s angle are essential parameters for analysing adolescent idiopathic scoliosis. This study’s scope evaluates the validity and absolute reliability of application software based on a new mathematical equation to determine the axial vertebral rotation in digital X-rays according to Raimondi’s method in evaluators with different degrees of experience. METHODS: Twelve independent evaluators with different experience levels measured 33 scoliotic curves in 21 X-rays with the software on three separate occasions, separated one month. Using the same methodology, the observers re-measured the same radiographic studies three months later but on X-ray films and in a conventional way. RESULTS: Both methods show good validity and reliability, and the intraclass correlation coefficients are almost perfect. According to our results, the software increases 1.7 times the validity and 1.9 times the absolute reliability of axial vertebral rotation on digital X-rays according to Raimondi’s method, compared to the conventional manual measurement. CONCLUSIONS: The intra-group and inter-group agreement of the measurements with the software shows equal or minor variations than with the manual method, among the different measurement sessions and in the three experience groups. There is almost perfect agreement between the two measurement methods, so the equation and the software may be helpful to increase the accuracy in the axial vertebral rotation assessment

    Diversity and relationships in key traits for functional and apparent quality in a collection of eggplant: fruit phenolics content, antioxidant activity, polyphenol oxidase activity, and browning

    Full text link
    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Agricultural and Food Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work seehttp://dx.doi.org/10.1021/jf402429kEggplant (Solanum melongena) varieties with increased levels of phenolics in the fruit present enhanced functional quality, but may display greater fruit flesh browning. We evaluated 18 eggplant accessions for fruit total phenolics content, chlorogenic acid content, DPPH scavenging activity, polyphenol oxidase (PPO) activity, liquid extract browning, and fruit flesh browning. For all the traits we found a high diversity, with differences among accessions of up to 3.36-fold for fruit flesh browning. Variation in total content in phenolics and in chlorogenic acid content accounted only for 18.9% and 6.0% in the variation in fruit flesh browning, and PPO activity was not significantly correlated with fruit flesh browning. Liquid extract browning was highly correlated with chlorogenic acid content (r = 0.852). Principal components analysis (PCA) identified four groups of accessions with different profiles for the traits studied. Results suggest that it is possible to develop new eggplant varieties with improved functional and apparent quality.This project has been funded by Universitat Politecnica de Valencia through the grants SP20120681 and PAID-06-11 Nr. 2082, and by Ministerio de Economia y Competitividad Grant AGL2012-34213 (jointly funded by FEDER).Plazas Ávila, MDLO.; López Gresa, MP.; Vilanova Navarro, S.; Torres Vidal, C.; Hurtado Ricart, M.; Gramazio, P.; Andújar Pérez, I.... (2013). Diversity and relationships in key traits for functional and apparent quality in a collection of eggplant: fruit phenolics content, antioxidant activity, polyphenol oxidase activity, and browning. Journal of Agricultural and Food Chemistry. 61(37):8871-8879. https://doi.org/10.1021/jf402429kS88718879613

    The SWR1 Histone Replacement Complex Causes Genetic Instability and Genome-Wide Transcription Misregulation in the Absence of H2A.Z

    Get PDF
    The SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription, gene silencing, chromosome segregation and DNA repair. Here we show that genetic instability, sensitivity to drugs impairing different cellular processes and genome-wide transcriptional misregulation in htz1Δ can be partially or totally suppressed if SWR1 is not formed (swr1Δ), if it forms but cannot bind to chromatin (swc2Δ) or if it binds to chromatin but lacks histone replacement activity (swc5Δ and the ATPase-dead swr1-K727G). These results suggest that in htz1Δ the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter. This would impair transcription and, either directly or indirectly, other cellular processes. Specifically, we show that in htz1Δ, the SWR1 complex causes an accumulation of recombinogenic DNA damage by a mechanism dependent on phosphorylation of H2A at Ser129, a modification that occurs in response to DNA damage, suggesting that the SWR1 complex impairs the repair of spontaneous DNA damage in htz1Δ. In addition, SWR1 causes DSBs sensitivity in htz1Δ; consistently, in the absence of Htz1 the SWR1 complex bound near an endonuclease HO-induced DSB at the mating-type (MAT) locus impairs DSB-induced checkpoint activation. Our results support a stepwise mechanism for the replacement of H2A with Htz1 and demonstrate that a tight control of this mechanism is essential to regulate chromatin dynamics but also to prevent the deleterious consequences of an incomplete nucleosome remodelling

    The stellar occultation by (319) Leona on 2023 September 13 in preparation for the occultation of Betelgeuse

    Full text link
    peer reviewedOn 2023 December 12, the star α Orionis will be occulted by asteroid (319) Leona. This represents an extraordinary and unique opportunity to analyse the brightness distribution of Betelgeuse's photosphere with extreme angular resolution by studying light curves from different points on Earth and at different wavelengths. Here we present observations of another occultation by asteroid Leona, on 2023 September 13, whose goal was to determine Leona's projected shape and size in preparation for the December 12th event and its interpretation. The occultation campaign was highly successful with 25 positive detections from 17 different sites and a near miss. The effective diameter in projected area derived from the positive detections was 66 ± 2 km using an elliptical fit to the instantaneous limb. The body is highly elongated, with dimensions of 79.6 ± 2.2 km × 54.8 ± 1.3 km in its long and short axis, respectively, at occultation time. This result, in combination with dense time series photometry of Leona that we recently obtained, together with archival sparse photometry, allowed us to predict the angular size of the asteroid for the Betelgeuse event and to simulate the expected brightness change. Also, an accurate position coming from the occultation is provided, to improve the orbit of Leona

    Resilience in Pre-Columbian Caribbean House-Building: Dialogue Between Archaeology and Humanitarian Shelter

    Get PDF
    This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s10745-015-9741-5This paper responds to questions posed by archaeologists and engineers in the humanitarian sector about relationships between shelter, disasters and resilience. Enabled by an increase in horizontal excavations combined with high-resolution settlement data from excavations in the Dominican Republic, the paper presents a synthesis of Caribbean house data spanning a millennium (1400 BP- 450 BP). An analysis of architectural traits identify the house as an institution that constitutes and catalyses change in an emergent and resilient pathway. The ?Caribbean architectural mode? emerged in a period of demographic expansion and cultural transition, was geographically widespread, different from earlier and mainland traditions and endured the hazards of island and coastal ecologies. We use archaeological analysis at the house level to consider the historical, ecological and regional dimensions of resilience in humanitarian actionThank you to the Museo del Hombre Dominicano for collaboration on the site of El Cabo, to the Netherlands Organisation for Scientific Research and the Faculty of Archaeology, Leiden University for supporting the archaeological research. Kate Crawford?s post-doctoral post at the Department of Civil, Environmental and Geomatic Engineering at University College London was funded by the Engineering and Physical Sciences Research Council

    Actas de las V Jornadas ScienCity 2022. Fomento de la Cultura Científica, Tecnológica y de Innovación en Ciudades Inteligentes

    Get PDF
    ScienCity es una actividad que viene siendo continuada desde 2018 con el objetivo de dar a conocer los conocimientos y tecnologías emergentes siendo investigados en las universidades, informar de experiencias, servicios e iniciativas puestas ya en marcha por instituciones y empresas, llegar hasta decisores políticos que podrían crear sinergias, incentivar la creación de ideas y posibilidades de desarrollo conjuntas, implicar y provocar la participación ciudadana, así como gestar una red internacional multidisciplinar de investigadores que garantice la continuación de futuras ediciones. En 2022 se recibieron un total de 48 trabajos repartidos en 25 ponencias y 24 pósteres pertenecientes a 98 autores de 14 instituciones distintas de España, Portugal, Polonia y Países Bajos.Fundación Española para la Ciencia y la Tecnología-Ministerio de Ciencia, Innovación y Universidades; Consejería de la Presidencia, Administración Pública e Interior de la Junta de Andalucía; Estrategia de Política de Investigación y Transferencia de la Universidad de Huelva; Cátedra de Innovación Social de Aguas de Huelva; Cátedra de la Provincia; Grupo de investigación TEP-192 de Control y Robótica; Centro de Investigación en Tecnología, Energía y Sostenibilidad (CITES

    Controls on explosive-effusive volcanic eruption styles

    Get PDF
    One of the biggest challenges in volcanic hazard assessment is to understand how and why eruptive style changes within the same eruptive period or even from one eruption to the next at a given volcano. This review evaluates the competing processes that lead to explosive and effusive eruptions of silicic magmas. Eruptive style depends on a set of feedbacks involving interrelated magmatic properties and processes. Foremost of these are magma viscosity, gas loss, and external properties such as conduit geometry. Ultimately, these parameters control the speed at which magmas ascend, decompress and outgas en route to the surface, and thus determine eruptive style and evolution
    corecore