1,083 research outputs found

    Racismo y lenguaje

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    Este libro busca contribuir al estudio de los procesos de racialización y de la construcción discursiva de nuevas identidades en el Perú contemporáneo. En lugar de abordar el racismo desde una dimensión cognitiva, se interesa por el rol que las prácticas lingüísticas cumplen en su constitución. Las diez contribuciones que integran este volumen examinan los discursos y las prácticas del racismo en ámbitos diversos y discuten las sutiles formas en las que se construye a un «otro» desde un criterio aparentemente no racial, pero bajo retóricas raciales de modo subyacente. Todos los artículos abordan la forma en que la raza en términos del fenotipo se ha articulado con otros criterios de clasificación, tales como la educación, la cultura, la clase, el territorio, el género, el lenguaje, entre otros

    Thermochromic Narrow Band Gap Phosphors for Multimodal Optical Thermometry: The Case of Y³⁺-Stabilized beta-Bi₂O₃:Nd³⁺

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    The design and development of effective luminescent thermal sensors have been driving technological progress in many different fields ranging from catalysis to biology and microelectronics, to name a few. The ratiometric concept of using the ratio between two luminescent emissions of lanthanide-doped phosphors allows overcoming some limitations resulting from the single emission-based thermometers. A fundamental requirement for the development of effective luminescent thermometers relies on efficient luminescence output, which is not always accessible. Therefore, alternative methods to probe the temperature in a reliable and simple way are still a challenge. Despite the conventional limits of using narrow band gap materials as hosts for lanthanoid ions, a smart design allows for the development of unusual phosphors with appealing properties. By taking advantage of the narrow band gap of Bi₂O₃ polymorphs, here we demonstrate the potential of the tetragonal Y-stabilized β-Bi₂O₃:Y³⁺, Nd³⁺ system as a multimodal thermometer combining the conventional Boltzmann thermometry based on Nd³⁺ together with the thermochromism of the host. With the aim of testing this new concept, the temperature dependence of the reflectance spectra was investigated. Moreover, from the application point of view, the chromaticity variations of the material described by means of simple thermometric parameters such as the ratio a*/b* and the hue angle hab are demonstrated to be particularly promising and already implemented in software commonly used worldwide. The results suggest the potential of the strategy of combining narrow band gap semiconductors with lanthanoid ions to design reliable and multimodal thermal sensors, paving the way to a new family of thermochromic and luminescent thermal sensors

    Chirality in luminescent Cs3Cu2Br5 microcrystals produced via ligand-assisted reprecipitation

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    Herein we report new chiral luminescent Cs3Cu2Br5 needle-like microcrystals and the analysis of their optical properties and the effect of the ligand structure on the transfer of chirality

    Designing Ln3+-doped BiF3 particles for luminescent primary thermometry and molecular logic

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    The design of molecular materials suitable for disparate fields could lead to new advances in engineering applications. In this work, a series of Ln3+-doped BiF3 sub-microparticles were synthesized through microwave-assisted synthesis. The effects of doping are evaluated from the structural and morphological viewpoint. In general, increasing the Ln3+ concentration the octahedral habitus is distorted to a spheric one, and some aggregates are visible without any differences in the crystalline phase. The optical response of the samples confirms that the BiF3 materials are suitable hosts for the luminescence of the tested trivalent lanthanide (Ln3+) ions (Ln = Eu, Tb, Tm, Ho, Er, Yb). A Yb3+/ Er3+ co-doped sample is presented as an illustrative example of all-photonic molecular logic operations and primary luminescent thermometry.publishe

    From SeaDataNet to SeaDataCloud: historical data collections and new data products

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    Temperature and Salinity historical data collections covering the time period 1900-2013/2014 were created for each European marginal sea (Arctic Sea, Baltic Sea, Black Sea, North Sea, North Atlantic Ocean, and Mediterranean Sea) within the framework of SeaDataNet2 Project and they are available as ODV collections through a web catalog (https://www.seadatanet.org/Products/Aggregated-datasets). Two versions have been published and they represent a snapshot of the SeaDataNet database content at two different times: V1.1 (January 2014) and V2 (March 2015). A Quality Control Strategy (QCS) was developped and continuously refined in order to improve the quality of the database content and create the best data products. The QCS consists of four main phases: 1) data harvesting from the data infrastructure; 2) file and parameter aggregation; 3) secondary quality check analysis; 4) correction of data anomalies. The approach is iterative to facilitate the upgrade of the database content and it allows a versioning of data products. Regional temperature and salinity monthly climatologies have been produced from V1.1 historical data collections and they are also available (https://www.seadatanet.org/Products/Climatologies). Within the new SeaDataCloud Project the release of updated historical data collections and new climatologies is planned. SeaDataCloud novelties are the introduction of decadal climatologies at various resolutions, the development of climatologies for the Global Ocean and a task dedicated to new data products, like Mixed Layer Depth climatologies, Ocean Heat Content estimates, coastal climatologies from HF radar data. All SeaDataCloud products are available through a dedicated web catalogue together with their relative Digital Object Identifier (DOI) and Product Information Document (PIDoc) containing all specifications about product’s generation, quality assessment and technical details to facilitate users’ uptake. The presentation will briefly overview the existing SeaDataNet products and introduce the SeaDataCloud products’ plan, but the main focus will be on the first release (February 2018) of SeaDataCloud Temperature and Salinity historical data collections, spanning the time period 1900-2017, their characteristics in terms of space-time data distribution and their usability.SeaDataCloud ProjectPublishedVienna4A. Oceanografia e clim

    Energy transfer in color-tunable water-dispersible Tb-Eu codoped CaF2 nanocrystals

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    The development of highly luminescent water-dispersible biocompatible nanoparticles is a hot topic in biomedical research. Here, we report about the study of the energy transfer process between Tb3+ and Eu3+ in calcium fluoride nanoparticles. Water-dispersible RE-doped nanoparticles were prepared by means of a simple synthesis route without the need for high temperature, pressure or additional surface functionalization. The structural and morphological properties were investigated by means of XRPD and TEM analysis. Optical analysis led to information about both the RE ion site symmetry in the crystalline host and the Tb3+ and Eu3+ excited state lifetimes, whose remarkable duration is suitable for biosensing applications. Concerning the energy transfer process, dipole-dipole interaction, with a donor-activator critical distance of about 13 Å, was identified as the most probable mechanism.The development of highly luminescent water-dispersible biocompatible nanoparticles is a hot topic in biomedical research. Here, we report about the study of the energy transfer process between Tb3+ and Eu3+ in calcium fluoride nanoparticles. Water-dispersible RE-doped nanoparticles were prepared by means of a simple synthesis route without the need for high temperature, pressure or additional surface functionalization. The structural and morphological properties were investigated by means of XRPD and TEM analysis. Optical analysis led to information about both the RE ion site symmetry in the crystalline host and the Tb3+ and Eu3+ excited state lifetimes, whose remarkable duration is suitable for biosensing applications. Concerning the energy transfer process, dipole-dipole interaction, with a donor-activator critical distance of about 13 angstrom, was identified as the most probable mechanism

    Accelerated chemical science with AI

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    In light of the pressing need for practical materials and molecular solutions to renewable energy and health problems, to name just two examples, one wonders how to accelerate research and development in the chemical sciences, so as to address the time it takes to bring materials from initial discovery to commercialization. Artificial intelligence (AI)-based techniques, in particular, are having a transformative and accelerating impact on many if not most, technological domains. To shed light on these questions, the authors and participants gathered in person for the ASLLA Symposium on the theme of ‘Accelerated Chemical Science with AI’ at Gangneung, Republic of Korea. We present the findings, ideas, comments, and often contentious opinions expressed during four panel discussions related to the respective general topics: ‘Data’, ‘New applications’, ‘Machine learning algorithms’, and ‘Education’. All discussions were recorded, transcribed into text using Open AI's Whisper, and summarized using LG AI Research's EXAONE LLM, followed by revision by all authors. For the broader benefit of current researchers, educators in higher education, and academic bodies such as associations, publishers, librarians, and companies, we provide chemistry-specific recommendations and summarize the resulting conclusions

    Thermodynamics of SU(N) Yang-Mills theories in 2+1 dimensions II - The deconfined phase

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    We present a non-perturbative study of the equation of state in the deconfined phase of Yang-Mills theories in D=2+1 dimensions. We introduce a holographic model, based on the improved holographic QCD model, from which we derive a non-trivial relation between the order of the deconfinement phase transition and the behavior of the trace of the energy-momentum tensor as a function of the temperature T. We compare the theoretical predictions of this holographic model with a new set of high-precision numerical results from lattice simulations of SU(N) theories with N=2, 3, 4, 5 and 6 colors. The latter reveal that, similarly to the D=3+1 case, the bulk equilibrium thermodynamic quantities (pressure, trace of the energy-momentum tensor, energy density and entropy density) exhibit nearly perfect proportionality to the number of gluons, and can be successfully compared with the holographic predictions in a broad range of temperatures. Finally, we also show that, again similarly to the D=3+1 case, the trace of the energy-momentum tensor appears to be proportional to T^2 in a wide temperature range, starting from approximately 1.2 T_c, where T_c denotes the critical deconfinement temperature.Comment: 2+36 pages, 10 figures; v2: comments added, curves showing the holographic predictions included in the plots of the pressure and energy and entropy densities, typos corrected: version published in JHE
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