Microbial weathering of Fe-rich phyllosilicates and formation of pyrite in the dolomite precipitating environment of a Miocene lacustrine system

Sedimentary sequences composed of selenite gypsum, mudstone, and dolomite microbialites cropping out in the eastern part of the Madrid Basin were deposited in a mudflat – saline-lake system during the Miocene. In some dolomite beds enriched in detrital grains, dolomite crystals occur intergrown with framboidal pyrite clusters that in many cases are arranged along the associated phyllosilicate cleavages, which accounts for the mineral disaggregation, and eventually for the mineral replacement. Highresolution FE-SEM investigations across the interface between the pyrite and the phyllosilicate show that a single phyllosilicate is replaced by iron sulphides in different microsites, with retention of some aspects of the parent structure. Pyrite formed in the sediment as texturally complex framboids, coexisting with amorphous to poorly crystalline iron-rich sulphide phases, and include carbonaceous filaments with biogenic isotopic signatures (δ 13 C = -22.95 ‰). Microprobe analytical data indicate the weathered phyllosilicates to be significantly depleted in Fe relative to Si and Al. The selective release of Fe has not involved the mineral transformation to secondary phyllosilicates, which suggests a preferential microbial colonization of the Fe-bearing minerals rather than a thermodynamically driven degradation of those minerals. Depleted δ 34 S values in pyrite further suggest that sulphate microbial reduction to sulphide was active within the sediment during the alteration of the silicates. This paper gives new insight into the microbial weathering of phyllosilicates and the subsequent formation of pyrite through a sequence of intermediate products enriched in iron. These processes were coeval with the microbially-mediated precipitation of dolomite, which further reinforces the role of the microbes in the formation of the sulphides

Efficient nickel and copper-based catalysts supported on modified graphite materials for the hydrogen production from formic acid decomposition

Ni, Cu and Ni-Cu catalysts supported on high surface area graphite were synthesized by incipient wet impregnation. Also, the effect of doping the graphite support with alkali oxides (Li, Na and K) was studied. The catalysts were tested in the formic acid decomposition reaction to produce hydrogen. The bimetallic Ni-Cu catalyst doped with K showed the best catalytic performance with 100% conversion of formic acid at 130 °C and a 95% of selectivity to hydrogen. The turnover frequency (TOF) of the catalysts follows the order: Ni-Cu/K > NiCu/Na > Ni-Cu > Ni-Cu/Li. While the order for the apparent activation energy values is: Ni-Cu > Ni-Cu/Li > Ni-Cu/Na > Ni-Cu/K. The mechanism of the reaction is approached by programmed temperature surface reaction (TPSR) experiments and attenuated total reflectance (ATR). The greater catalytic activity of the Ni-Cu catalyst doped with potassium is ascribed to the lower stability of the formate, bicarbonate and carbonate species on its surface.Fil: Faroldi, Betina María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina. Consejo Superior de Investigaciones Científicas. Instituto de Catálisis y Petroleoquímica; EspañaFil: Conesa, J. M.. Consejo Superior de Investigaciones Científicas. Instituto de Catálisis y Petroleoquímica; EspañaFil: Guerrero Ruiz, A.. Universidad Nacional de Educacion A Distancia. Facultad de Ciencias.; EspañaFil: Rodríguez Ramos, I.. Consejo Superior de Investigaciones Científicas. Instituto de Catálisis y Petroleoquímica; Españ

Rapid synthesis of MCM-41 and SBA-15 by microwave irradiation: promising adsorbents for CO2 adsorption

It is known that the world scenario is one of constant search for sustainable technologies that can reduce the emission of carbon dioxide (CO2) in the atmosphere. This is because CO2 is seen as the main responsible for the increase in the generation of greenhouse gases, which leads to global warming and climate change. The development of efficient adsorbents for CO2 capture is a current challenge. MCM-41 and SBA-15 were synthesized in a microwave reactor and used as adsorbents in this work. Microwave irradiation presents itself as an easy synthesis strategy with less preparation time and energy requirement. The silica synthesis period was extremely reduced (1 h) at a temperature of 60 and 80 °C in the microwave reactor, obtaining silica with good textural and chemical properties. The CO2 adsorption isotherms were performed at 0, 25, and 40 °C at 1 bar. The MCM-41 and SBA-15 present favorable results for CO2 capture processes, showing that pure silica synthesized by microwave already obtains promising results, reaching a maximum adsorption capacity of 2.16 mmol g−1 (1 bar—0 °C) and a good fit for the Langmuir, DsL and Toth models. Furthermore, to increase CO2 adsorption, the mesoporous silica was also modified via impregnation with branched polyethylene diamine (PEI) or tetraethylenepentamine (TEPA). It is worth mentioning that microwave irradiation reduced the synthesis steps and improved the properties and adsorption capacity of the silica. This work opens new opportunities in the efficient preparation of materials that require optimizing the adsorbent synthesis process.The authors thank you to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, National Council for Scientific and Technological Development, Brazil) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Higher Education Personnel Improvement Coordination, Brazil, CAPES—financing code 001) for financial support. This research was also funded by the Ministry of Science, Innovation and Universities (Spain), Grants Nos. RTI2018-099668-B-C22 and PID2021-126235OB-C32, and projects UMA18-FEDERJA-126 and P20_00375 of Junta de Andalucía and FEDER funds. // Funding for open access publishing: Universidad Málaga/CBUA

The validity and reliability of a novel app for the measurement of change of direction performance

The aim of the present investigation was to analyze the validity and reliability of a novel iPhone app (CODTimer) for the measurement of total time and interlimb asymmetry in the 5 + 5 change of direction test (COD). To do so, twenty physically active adolescent athletes (age = 13.85 ± 1.34 years) performed six repetitions in the COD test while being measured with a pair of timing gates and CODTimer. A total of 120 COD times measured both with the timing gates and the app were then compared for validity and reliability purposes. There was an almost perfect correlation between the timing gates and the CODTimer app for the measurement of total time (r = 0.964; 95% Confidence interval (CI) = 0.95-1.00; Standard error of the estimate = 0.03 s.; p  0.05). Similar levels of reliability were observed between the timing gates and the app for the measurement of the 6 different trials of each participant (Timing gates: Intraclass correlation coefficient (ICC) = 0.651-0.747, Coefficient of variation (CV) = 2.6-3.5%; CODTimer: ICC = 0.671-0.840, CV = 2.2-3.2%). The results of the present study show that change of direction performance can be measured in a valid, reliable way using a novel iPhone app

Cine y comprensión. Investigar en el aula universitaria

El propósito del presente trabajo es narrar una experiencia de investigación en formación docente que incluyó la introducción del video cine en el aula universitaria.Desde los postulados teóricos del proyecto de investigación en el cual participamos “Las prácticas educomunicacionales. Su impacto en la comprensión de los sujetos que interactúan en situaciones de enseñanza y de aprendizaje”, se sostiene con fuerza que estamos en una era tecnológica en la cual los medios de comunicación masiva impactan a la humanidad entera, niños y jóvenes, aprenden muchas cosas de los mismos: pautas culturales, modos de relacionarse, maneras de conocer, formas de pensar y de actuar. Las nuevas generaciones crecen y conocen la realidad a través de ellas.El problema que se suscitó era como lograr una auténtica comprensión de los contenidos que se desarrollaban en la asignatura Didáctica dictada para el Profesorado y Licenciatura en Educación Inicial. Esto llevó a pensar en la inclusión del cine como parte de las estrategias de enseñanza. Para tal fin se seleccionó el filme “La sociedad de los poetas muertos”.La metodología consistió en la realización de un texto narrativo elaborado por las alumnas a posteriori del visionado del video, con el propósito de poder “mirar” la relación que se establecía entre los contenidos teóricos desarrollados en la asignatura y la historia propuesta por el filme. El análisis cualitativo de los aspectos recurrentes y divergentes de los textos, permitió detectar las significaciones con las cuales se explicitaba la compresión alcanzada por las alumnas. Desde este decir fue posible establecer reflexiones que permitieron resignificar aspectos teóricos desarrollados en la asignatura como así también visualizar la importancia que se atribuyó a la incorporación del video-cine en el aula

Hydrogen Production by Formic Acid Decomposition over Ca Promoted Ni/SiO2 Catalysts: Effect of the Calcium Content

Formic acid, a major product of biomass processing, is regarded as a potential liquid carrier for hydrogen storage and delivery. The catalytic dehydrogenation of FA to generate hydrogen using heterogeneous catalysts is of great interest. Ni based catalysts supported on silica were synthesized by incipient wet impregnation. The eect of doping with an alkaline earth metal (calcium) wasstudied, and the solids were tested in the formic acid decomposition reaction to produce hydrogen.The catalysts were characterized by X-ray diraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and programmed temperature surface reaction (TPSR).The catalyst doped with 19.3 wt.% of Ca showed 100% conversion of formic acid at 160 C, with a 92% of selectivity to hydrogen. In addition, all the tested materials were promising for their application, since they showed catalytic behaviors (conversion and selectivity to hydrogen) comparable to thoseof noble metals reported in the literature.Fil: Faroldi, Betina María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Paviotti, María Aneley. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Camino-Manjarrés, M.. Universidad de Salamanca; EspañaFil: González-Carrazán, S.. Universidad de Salamanca; EspañaFil: López-Olmos, C.. Consejo Superior de Investigaciones Científicas. Instituto de Catálisis y Petroleoquímica; EspañaFil: Rodríguez-Ramos, I.. Consejo Superior de Investigaciones Científicas. Instituto de Catálisis y Petroleoquímica; Españ

Copper nanoparticles synthesis in hybrid mesoporous thin films: Controlling oxidation state and catalytic performance through pore chemistry

The room temperature synthesis of copper (Cu) nanoparticles (NPs) supported within SiO2 mesoporous thin films (MTF) modified with either COOH or NH2 functional groups is reported. The functional groups present in the MTF surface acted as adsorption sites for Cu (II) ions, which were afterwards reduced to Cu NPs in presence of sodium borohydride at room temperature. The oxidation state of the copper NPs, corroborated by X-ray Photoelectron Spectroscopy and Electron Energy Loss Spectroscopy, was strongly dependent on the functional group present in the pores of the MTF and on the number of adsorption/reduction (A/R) cycles applied for NPs loading. Metallic Cu (0) NPs were obtained in MTFs displaying COOH groups applying 10 A/R cycles while NPs with higher oxidation state were as well present after 20 A/R cycles. For MTF functionalized with NH2 groups the copper is present as Cu (I) and Cu(II) in the NPs but no Cu (0) can be detected. The MTF-Cu(CuOx) composite materials were tested as catalysts for the reduction of 4-nitrophenol in the presence of NaBH4. Catalytic activity of composite materials depends on the oxidation state of Cu NPs, being more active those samples containing Cu (0) NPs, synthesized from COOH functionalized MTFs.Fil: Coneo Rodríguez, Rusbel. Comisión Nacional de Energía Atómica. Gerencia del Área de Seguridad Nuclear y Ambiente. Gerencia de Química (CAC); Argentina. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; ArgentinaFil: Yate, Luis. No especifíca;Fil: Coy, Emerson. Adam Mickiewicz University; PoloniaFil: Martínez Villacorta, Ángel M.. No especifíca;Fil: Bordoni, Andrea Veronica. Comisión Nacional de Energía Atómica. Gerencia del Área de Seguridad Nuclear y Ambiente. Gerencia de Química (CAC); Argentina. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; ArgentinaFil: Moya, Sergio. No especifíca;Fil: Angelome, Paula Cecilia. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Seguridad Nuclear y Ambiente. Gerencia de Química (CAC); Argentin

Objective of training of beekeeping organizations in Buenos Aires Province

Desde finales de la década de los ´80, en América Latina, los pequeños y medianos productores se han organizado en agrupaciones de pequeña escala con el objeto de enfrentar situaciones que de forma independiente les es imposible solucionar. En la Argentina, la apicultura, es uno de los blancos objetivos de estos procesos organizativos, donde la necesidad de dar solución a problemáticas productivas y comerciales, como requisito excluyente de permanencia en el circuito productivo, se constituye como incentivo de los procesos de agrupación. La provincia de Buenos Aires es la que centraliza la mayor cantidad de apicultores y de organizaciones apícolas, que se manifiestan en el territorio participando de la constante transformación e infinitas modalidades de gestión entre seres humanos, el Estado y el mercado. En este contexto es que se definió como objetivo del presente trabajo estudiar las organizaciones apícolas existentes en la provincia, visualizando sus objetivos de formación y las particularidades que las caracterizan.Facultad de Ciencias Agrarias y ForestalesFacultad de Ciencias Veterinaria