10 research outputs found

    Optimizing Accuracy and Computational Cost in Theoretical Squaramide Catalysis: the Henry Reaction

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    This study represents the first example where the accuracy of different combinations of density functional theory (DFT) methods and basis sets has been compared in squaramide catalysis. After an optimization process of the precision obtained and the computational time required in the computational calculations, highly precise results were achieved compared to the experimental outcomes while using the least amount of time as possible. Here, we have explored computationally and experimentally the mechanism of squaramide-catalyzed Henry reaction. This is a complex reaction of about 100 atoms and a great number of diverse non-covalent interactions. Moreover, this research is one of the scarce examples where the organocatalyst acts in a trifunctional manner and is the first investigation in which a trifunctional squaramide catalyst has been employed. Functional ¿B97X-D showed the best results when used with different versions of the 6-311 basis sets, leading to highly accurate calculations of the outcomes of the Henry reaction using nine aldehydes with different structural characteristics. Furthermore, in these relatively large systems, the use of a split-valence triple-zeta basis set saves a large amount of time compared to using larger basis sets that are sometimes employed in organocatalytic studies, such as the TZV and Def2TZV basis set families

    Metal-organic frameworks (MOFs) bring new life to hydrogen-bonding organocatalysts in confined spaces

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    Hydrogen-bonding organocatalysis has emerged as a promising biomimetic alternative to Lewis acid catalysis. Urea, thiourea and squaramide moieties represent the most common hydrogen-bond donors used for the preparation of these catalysts. However, their significant tendency to undergo self-quenching (self-aggregation) often decreases their solubility and reactivity. Recently, scientists have found a promising way around this problem by immobilizing the hydrogen-bonding organocatalysts on metal–organic frameworks (MOFs). Along with advantageous modular synthesis and recycling properties, the tunable porosity and topology of MOFs also allows fast mass transport and/or interactions with substrates. Herein, we highlight the existing examples dealing with the fabrication and testing of hydrogen-bonding organocatalyst-containing MOFs, providing also our vision for further advances in this area. The results derived from these studies will likely serve as inspiration for the future development of superior hydrogen-bonding organocatalysts to accomplish in confined spaces chemical transformations that are either slow or unaffordable under standard homogeneous conditions

    Contaminación lumínica en el Anillo verde de Vitoria-Gasteiz

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    Este trabajo ha consistido en tomar mediciones de la cantidad de iluminación que reciben distintos ecosistemas alrededor de la ciudad de Vitoria-Gasteiz, para posteriormente analizar y valorar esas mediciones. En primer lugar, se hizo una valoración medioambiental de los distintos espacios, haciendo referencia a los servicios ambientales que prestan y a la flora y fauna presente. En segundo lugar, se tomaron mediciones de la contaminación lumínica de los distintos espacios para así poder comparar y analizar posibles diferencias existentes. Posteriormente se han expuesto los efectos adversos de la contaminación lumínica sobre la salud y el medio ambiente. Por último, se han propuesto actuaciones para mitigar la contaminación lumínica y así contribuir al ahorro energético.<br /

    Studies on the Synthesis of 2-Alkyl-5-aryl-1,3,4-oxadiazolines from N-Acylhydrazones

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    Reaction of N-acylhydrazones with benzyloxyacetyl chloride in the presence of i-Pr 2EtN affords new 1,3,4-oxadiazolines in excellent yields (72-95%), under mild reaction conditions and in short reaction times. The structures of the products were confirmed by single-crystal X-ray diffractometry. A plausible reaction mechanism is proposedMinisterio de Ciencia e Innovación CTQ2010-15297, CTQ2010-14974Junta de Andalucía 2008/ FQM-3833, 2009/FQM-453

    Taxonomic and functional metagenomic profiling of the microbial community in the anoxic sediment of a sub-saline Shallow Lake (Laguna de Carrizo, Central Spain)

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    The phylogenetic and functional structure of the microbial community residing in a Ca2+-rich anoxic sediment of a sub-saline shallow lake (Laguna de Carrizo, initially operated as a gypsum (CaSO4 × 2 H2O) mine) was estimated by analyzing the diversity of 16S rRNA amplicons and a 3.1 Mb of consensus metagenome sequence. The lake has about half the salinity of seawater and possesses an unusual relative concentration of ions, with Ca2+ and SO 4 2- being dominant. The 16S rRNA sequences revealed a diverse community with about 22% of the bacterial rRNAs being less than 94.5% similar to any rRNA currently deposited in GenBank. In addition to this, about 79% of the archaeal rRNA genes were mostly related to uncultured Euryarchaeota of the CCA47 group, which are often associated with marine and oxygen-depleted sites. Sequence analysis of assembled genes revealed that 23% of the open reading frames of the metagenome library had no hits in the database. Among annotated genes, functions related to (thio) sulfate and (thio) sulfonate-reduction and iron-oxidation, sulfur-oxidation, denitrification, synthrophism, and phototrophic sulfur metabolism were found as predominant. Phylogenetic and biochemical analyses indicate that the inherent physical–chemical characteristics of this habitat coupled with adaptation to anthropogenic activities have resulted in a highly efficient community for the assimilation of polysulfides, sulfoxides, and organosulfonates together with nitro-, nitrile-, and cyanide-substituted compounds. We discuss that the relevant microbial composition and metabolic capacities at Laguna de Carrizo, likely developed as an adaptation to thrive in the presence of moderate salinity conditions and potential toxic bio-molecules, in contrast with the properties of previously known anoxic sediments of shallow lakes.This research was supported by the Spanish CSD2007-00005 project and FEDER funds. M-E.G. thanks the CSIC for a JAE fellowship.Peer Reviewe

    Glotopolítica latinoamericana : Tendencias y perspectivas

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    Glotopolítica latinoamericana: tendencias y perspectivas recoge el resultado de presentaciones y deliberaciones del IV Congreso Latinoamericano de Glotopolítica, realizado en la Universidad de San Pablo (Brasil) en septiembre de 2019, que convocó a numerosos y destacados especialistas en el área. Su inscripción en una serie (los anteriores se realizaron en Chile, Colombia y Alemania) nos permite apreciar los grandes ejes de los que da cuenta el cuidadoso e inteligente armado del libro decidido por los editores, y fundamentado en la Presentación. El tramo que hemos recorrido como especialistas, en el cual los eventos internacionales son hitos significativos, ha ido mostrando la amplitud de un campo que se construye apelando a tradiciones académicas variadas, que insiste en su carácter interdisciplinario y crítico y que no deja de tener una dimensión militante que se expone en las reflexiones teóricas, las investigaciones empíricas y las prácticas institucionales

    La importancia de conocer el idioma

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    Este proyecto consiste en mejorar el uso cotidiano de la lengua castellana, abordándola desde el vocabulario, la ortografía y la compresión lectora en las distintas asignaturas. Para dar mayor globalidad al ejercicio, se trabaja también estos factores en otros idiomas como el inglés y el francés. Los objetivos son desarrollar un vocabulario adecuado a las distintas materias; escribir correctamente; trabajar la comprensión de los textos; aumentar la cohesión y la coordinación entre alumnos y profesores; fomentar la utilización de distintos métodos de enseñanza-aprendizaje; fomentar el interés con actividades motivadoras e innovadoras en la enseñanza curricular; y potenciar el trabajo en grupo e individual. Las actividades llevadas a la práctica son acordes a la edad y a los objetivos propuestos. Se elaboran listados de palabras de ortografía dudosa, se trabajan textos para acceder a su comprensión, se hacen concursos de ortografía, se cuelgan carteles por pasillos y aulas con palabras significativas, se fabrican tarjetas para jugar-aprendiendo en clases y tutorías, y se utilizan programas de ordenador que refuerzan el aprendizaje de vocabulario y ortografía. La metodología pone en activo tanto a profesores como a alumnos. Los primeros se encargan de hacer los listados de palabras y de preparar y dar formato a las pruebas eliminatorias del concurso. Los alumnos se encargan de buscar la información necesaria para definir las palabras, hacer los carteles y exponer las conclusiones. La evaluación consiste principalmente en reuniones de profesores que analizan el desarrollo del proyecto, exponen las dificultades encontradas y establecen modificaciones y correcciones en relación a los ejercicios. Como anexo se presentan dos CD-ROM con las actividades realizadas..Madrid (Comunidad Autónoma). Consejería de Educación. Dirección General de Mejora de la Calidad de la EnseñanzaMadridMadrid (Comunidad Autónoma). Subdirección General de Formación del Profesorado. CRIF Las Acacias; General Ricardos 179 - 28025 Madrid; Tel. + 34915250893ES

    Relationship of Weather Types on the Seasonal and Spatial Variability of Rainfall, Runoff, and Sediment Yield in the Western Mediterranean Basin

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    Rainfall is the key factor to understand soil erosion processes, mechanisms, and rates. Most research was conducted to determine rainfall characteristics and their relationship with soil erosion (erosivity) but there is little information about how atmospheric patterns control soil losses, and this is important to enable sustainable environmental planning and risk prevention. We investigated the temporal and spatial variability of the relationships of rainfall, runoff, and sediment yield with atmospheric patterns (weather types, WTs) in the western Mediterranean basin. For this purpose, we analyzed a large database of rainfall events collected between 1985 and 2015 in 46 experimental plots and catchments with the aim to: (i) evaluate seasonal differences in the contribution of rainfall, runoff, and sediment yield produced by the WTs; and (ii) to analyze the seasonal efficiency of the different WTs (relation frequency and magnitude) related to rainfall, runoff, and sediment yield. The results indicate two different temporal patterns: the first weather type exhibits (during the cold period: autumn and winter) westerly flows that produce the highest rainfall, runoff, and sediment yield values throughout the territory; the second weather type exhibits easterly flows that predominate during the warm period (spring and summer) and it is located on the Mediterranean coast of the Iberian Peninsula. However, the cyclonic situations present high frequency throughout the whole year with a large influence extended around the western Mediterranean basin. Contrary, the anticyclonic situations, despite of its high frequency, do not contribute significantly to the total rainfall, runoff, and sediment (showing the lowest efficiency) because of atmospheric stability that currently characterize this atmospheric pattern. Our approach helps to better understand the relationship of WTs on the seasonal and spatial variability of rainfall, runoff and sediment yield with a regional scale based on the large dataset and number of soil erosion experimental stations.Spanish Government (Ministry of Economy and Competitiveness, MINECO) and FEDER Projects: CGL2014 52135-C3-3-R, ESP2017-89463-C3-3-R, CGL2014-59946-R, CGL2015-65569-R, CGL2015-64284-C2-2-R, CGL2015-64284-C2-1-R, CGL2016-78075-P, GL2008-02879/BTE, LEDDRA 243857, RECARE-FP7, CGL2017-83866-C3-1-R, and PCIN-2017-061/AEI. Dhais Peña-Angulo received a “Juan de la Cierva” postdoctoral contract (FJCI-2017-33652 Spanish Ministry of Economy and Competitiveness, MEC). Ana Lucia acknowledge the "Brigitte-Schlieben-Lange-Programm". The “Geoenvironmental Processes and Global Change” (E02_17R) was financed by the Aragón Government and the European Social Fund. José Andrés López-Tarazón acknowledges the Secretariat for Universities and Research of the Department of the Economy and Knowledge of the Autonomous Government of Catalonia for supporting the Consolidated Research Group 2014 SGR 645 (RIUS- Fluvial Dynamics Research Group). Artemi Cerdà thank the funding of the OCDE TAD/CRP JA00088807. José Martínez-Fernandez acknowledges the project Unidad de Excelencia CLU-2018-04 co-funded by FEDER and Castilla y León Government. Ane Zabaleta is supported by the Hydro-Environmental Processes consolidated research group (IT1029-16, Basque Government). This paper has the benefit of the Lab and Field Data Pool created within the framework of the COST action CONNECTEUR (ES1306)

    Spatial variability of the relationships of runoff and sediment yield with weather types throughout the Mediterranean basin

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    Este artículo contiene 16 páginas, 6 figuras, 2 tablas.Soil degradation by water is a serious environmental problem worldwide, with specific climatic factors being the major causes. We investigated the relationships between synoptic atmospheric patterns (i.e. weather types, WTs) and runoff, erosion and sediment yield throughout the Mediterranean basin by analyzing a large database of natural rainfall events at 68 research sites in 9 countries. Principal Component Analysis (PCA) was used to identify spatial relationships of the different WTs including three hydro-sedimentary variables: rainfall, runoff, and sediment yield (SY, used to refer to both soil erosion measured at plot scale and sediment yield registered at catchment scale). The results indicated 4 spatial classes of rainfall and runoff: (a) northern sites dependent on North (N) and North West (NW) flows; (b) eastern sites dependent on E and NE flows; (c) southern sites dependent on S and SE flows; and, finally, (d) western sites dependent on W and SW flows. Conversely, three spatial classes are identified for SY characterized by: (a) N and NE flows in northern sites (b) E flows in eastern sites, and (c) Wand SW flows in western sites. Most of the rainfall, runoff and SY occurred during a small number of daily events, and just a few WTs accounted for large percentages of the total. Our results confirm that characterization by WT improves understanding of the general conditions under which runoff and SY occur, and provides useful information for understanding the spatial variability of runoff, and SY throughout the Mediterranean basin. The approach used here could be useful to aid of the design of regional water management and soil conservation measures.This research was supported by projects funded by the MINECOFEDER: CGL2014-52135-C3-3-R, CGL2014-59946-R, CGL2015-65569- R, CGL2015-64284-C2-2-R, and PCIN-2017-061/AEI. When this manuscript was first submitted Estela Nadal-Romero and Damià Vericat received a “Ramón y Cajal” postdoctoral contract (RYC-2013-14371 and RYC‐2010‐06264, Spanish Ministry of Economy and Competitiveness, MEC). Damià Vericat is now a Serra Húnter Fellow at the University of Lleida. María Fernández-Raga received a “José Castillejo” postdoctoral grant (Spanish Ministry of Education, Culture and Sports). Carla Ferreira was supported by a post-doctoral research grant from the Portuguese Science and Technology Foundation (SFRH/ BPD/120093/2016). Mariano Moreno-de las Heras received a Juan de la Cierva postdoctoral contract (IJCI-2015-26463) from the MEC. José Andrés López-Tarazón received a Vicenç Mut postdoctoral fellowship from the Autonomous Balearic Government (CAIB PD/038/2016). José Andrés López-Tarazón and Ramon Batalla also acknowledge the Secretariat for Universities and Research of the Department of the Economy and Knowledge of the Autonomous Government of Catalonia for supporting the Consolidated Research Group 2014 SGR 645 (RIUSFluvial Dynamics Research Group), and the CERCA Programme. This paper has benefited from the Lab and Field Data Pool created within the framework of the COST action CONNECTEUR (ES1306).Peer reviewe

    Analysis of the spatial variability of the relationships between rainfall, runoff, erosion and sediment yield and synoptic atmospheric patterns around the Mediterranean basin

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    Trabajo presentado en TERRAenVISION Environmental Issues Today: Scientific Solutions for Societal Issues, celebrado en Barcelona (España) del 27 de enero al 2 de febrero de 2018This contribution results from international collaborative efforts of different research groups around the Mediterranean basin focusing on soil conservation and water management. We will present the most complete database of runoff and soil erosion information and analyze the records from 68 locations, including more than 22458 detail events between 1985-2015. Soil conservation and water planning are two of the most challenging problems around the Mediterranean basin due to climate conditions and human activity. We believe that future advances on understanding soil degradation by water should be developed under global approaches. In this contribution, we will present an analysis of atmospheric conditions, expressed by weather types and the resulted rainfall, runoff, and erosion and sediment yield around the Mediterranean basin. The weather types compile daily information about the different air masses responsible for rainfall, runoff and eventually erosion and sediment yield, and their analyses let us know the synchrony of the response at different sites around the Mediterranean basin. The analyses of the global dataset display different spatial patterns for rainfall, runoff, and sediment yield, related to different atmospheric patterns. This research will be a valuable tool for understanding the evolution of these environmental variables, and therefore it will allow future planning to design regional water management and soil conservation measuresPeer reviewe
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