Secondary REE-minerals in the karst bauxites of the Bahoruco Peninsula (Dominican Republic)

Rare earth elements (REE) are essential for numerous technological applications. Currently about 90% of the worldwide REE demand is supplied by China (Hatch, 2012), and therefore REE are defined as critical metals (Dutta et al., 2016). Bauxites, the main source for Al in the world, gained interest since they are capable of concentrating significant amounts of REE (Liu et al., 2016), and have been recently considered unconventional deposits for REE (Goodenough et al., 2017). Two types of bauxitic deposits are defined: a) lateritic bauxites (formed after intense weathering of an Al-bearing protolith), and b) karst bauxites (of controversial origin, hosted in carbonaceous rocks). One hypothesis of karst bauxite formation suggests dissolution of the carbonates, whereas the other implies an external contribution of Al-bearing minerals during or after carbonate deposition (Bárdossy, 1982)

Yeasts associated with the production of distilled alcoholic beverages

Distilled alcoholic beverages are produced firstly by fermenting sugars emanating from cereal starches (in the case of whiskies), sucrose-rich plants (in the case of rums), fructooligosaccharide-rich plants (in the case of tequila) or from fruits (in the case of brandies). Traditionally, such fermentations were conducted in a spontaneous fashion, relying on indigenous microbiota, including wild yeasts. In modern practices, selected strains of Saccharomyces cerevisiae are employed to produce high levels of ethanol together with numerous secondary metabolites (eg. higher alcohols, esters, carbonyls etc.) which greatly influence the final flavour and aroma characteristics of spirits following distillation of the fermented wash. Therefore, distillers, like winemakers, must carefully choose their yeast strain which will be very important in providing the alcohol content and the sensory profiles of spirit beverages. This Chapter discusses yeast and fermentation aspects associated with the production of selected distilled spirits and highlights similarities and differences with the production of wine

Tenacidad a la fractura de compuestos cermets 3Al2O3*2SiO2/Ag manufacturados por molienda de alta energía

La fabricación de materiales compuestos de matriz cerámica reforzados con partículas metálicas han propiciado la formación de nuevos materiales conocidos como compuestos CERMETS, materiales que debido a sus elementos precursores poseen propiedades distintas a las de los materiales convencionales. En este trabajo se establece la ruta de fabricación de materiales compuestos cermets base 3Al2O3*2SiO2 reforzados con partículas metálicas de Ag a partir de la formación de la composición química en peso de polvos de 3Al2O3*2SiO2 / 1% Ag en busca de un aumento en la tenacidad a la fractura con respecto al cerámico base. La composición química de polvos es sometida a un proceso de mezcla molienda de alta energía en seco en un molino tipo planetario por 2 horas a 200 rpm. Los polvos posteriormente son conformados en muestras cilíndricas de 20 mm de diámetro y 3 mm de espesor mediante la aplicación de carga uniaxial en frío de 200 MPa. Las muestras son sinterizadas a 1500°C y 1600°C por una y dos horas en un horno de resistencia eléctrica en atmósfera controlada de gas nitrógeno. Los compuestos fabricados son analizados microestructuralmente por microscopia óptica y electrónica de barrido. Se determina la densidad y las propiedades mecánicas de dureza y tenacidad a la fractura, las dos últimas por el método de indentación. Los resultados muestran la viabilidad de fabricación de materiales compuestos cermets así como los cambios en la densidad, la dureza y la tenacidad a la fractura, con respecto al cerámico 3Al2O3*2SiO2 sin refuerzo metálico

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Enhanced anaerobic treatment of synthetic protein-rich wastewater promoted by organic xerogels

Carbon-based materials have been shown to enhance anaerobic digestion processes by promoting direct interspecies electron transfer in methanogenic consortia. However, little is known on their effects during the treatment of complex substrates, such as those derived from protein-rich wastewaters. Here, organic xerogels (OX) are tested, for the first time, as accelerators of the methanogenic activity of an anaerobic consortium treating a synthetic protein-rich wastewater. Three OX with distinct pore size distribution (10 and 1000 nm for OX-10 and OX-1000, respectively) and structural conformation (graphene oxide integration into OX-10-GO polymeric matrix) were synthesized. OX-1000 promoted the highest methane production rate (5.21 mL/g*h, 13.5% increase with respect to the control incubated without OX) among the synthesized OX. Additionally, batch bioreactors amended with OX achieved higher chemical oxygen demand (COD) removal (up to 88%) as compared to the control, which only showed 50% of COD removal. Interestingly, amendment of bioreactors with OX also triggered the production of medium-chain fatty acids, including caprylate and caproate. Moreover, OX decreased the accumulation of ammonium, derived from proteins hydrolysis, partly explained by their adsorption capacities, and probably involving their electron-accepting capacity promoting anaerobic ammonium oxidation. This is the first time that OX were successfully applied as methanogenic accelerators for the anaerobic treatment of synthetic protein-rich wastewater, increasing the methane production rate and COD removal as well as triggering the production of medium chain fatty acids and attenuating the accumulation of ammonium. Therefore, OX are proposed as suitable materials to boost the efficiency of anaerobic systems to treat complex industrial wastewaters.Universidad Nacional Autónoma de México (UNAM, PAPIIT grant TA100120 and UNAM, DGAPA Grant Number COIC/DDTPA/064/2020).Peer reviewe

Decay in chloride content of ground water due to excessive production of a well field near León, Mexico

El campo de pozos de La Muralla, cerca de León, Guanajuato, México, extrae agua por medio de 19 pozos profundos. Los 629 análisis del cloruro del agua extraída entre 1994 y 1999 muestran una tendencia global decreciente de - 1.1 mg/L por año, estimada por regresión lineal. Si esta demineralización continúa, en pocos años el agua alcanzaría la misma composición de la lluvia. Los resultados sugieren una severa reducción en la reserva de agua del acuífero

Stratigraphy of the Balsas Group in the Amacuzac area, southern Mexico: relationship with Eocene volcanism and deformation of the Tilzapotla-Taxco sector

The Zapalco-Amacuzac area in the Morelos and Guerrero states, southern Mexico, constitutes one of the classic sectors where Paleogene continental beds of the Balsas Group were originally described. The exposed succession has an apparent thickness of ~2,500 m and it is constituted by two distinct sedimentary units separated by a slightly angular unconformity and by two intercalated ignimbrites (35.1 ± 0.4 and 38.5 ± 0.7 Ma, sanidine, K-Ar). The basal beds of the lower sedimentary unit (Tepetlapa Formation) are constituted by matrix-supported conglomerates that grade upwards to sandstone with a poorly defined planar parallel stratification and some intercalated andesitic and mafic lava flows. One of the andesites yielded a whole rock K-Ar date of 44.5 ± 0.7 Ma. Intercalations of conglomerate beds increase again toward the top of this unit. The upper sedimentary unit (Huajintlán Formation) is constituted by a ~300 m thick succession of matrix-supported conglomerate with some lenses of conglomeratic sandstone. This unit unconformably underlies the Tilzapotla ignimbrite whose best age estimate is 34.3 Ma (sanidine Ar-Ar). The beds of the two sedimentary formations dip east to northeast with higher dips for the lower unit (50-30º). Recognized facies in both units are indicative of an alluvial fan environment with more proximal facies for the Huajintlán Formation. The studied succession is located immediately northwest of a large elliptical (50×30 km) dome structure that resulted from the tumescence stage, in the early evolution of the Tilzapotla caldera, previous to the collapse. The northwestern termination of the dome merges and interferes with the NNE-trending Laramide fold and thrust front of the Iguala Cacahuamilpa highs, near Taxco. In the study area, the dome contours display a local inflection defined by a change in the dip direction of the Morelos and basal beds of the Tepetlapa Formation from north to east. The slight angular unconformity between the Tepetlapa Formation and the overlaying units indicates a first stage of eastward tilting related to an uplift episode in the Taxco area, probably originated by the emplacement of silicic magmas (ca. 38 Ma). The proximal facies of the overlaying Huajintlán Formation and the age (35.1 ± 0.4 Ma) of the Piedras Altas Tuff , indicate that this formation resulted from the rejuvenation of the source area triggered by the tumescence and the initiation of the volcanic activity in the nearby Tilzapotla caldera area. This is confirmed by the higher dips (~50º) of the Tepetlapa Formation near the dome structure and the decreasing dips toward the northeast. The age of one andesite lava flow (44.5 Ma) intercalated in the lower unit is indicative of an Eocene age for the beginning of the Balsas Group accumulation in this areaEl área de Amacuzac-Zacapalco, estados de Morelos y Guerrero, constituye una de las áreas clásicas en donde el grupo Balsas fue descrito originalmente. La sucesión expuesta en esta zona tiene un espesor aparente de ~2,500 m y está formada por dos unidades separadas por una ligera discordancia angular y por dos ignimbritas intercaladas (35.1 ± 0.4 y 38.5 ± 0.7 Ma, K-Ar en sanidino). La unidad inferior (Formación Tepetlapa) presenta en su base conglomerados matriz-soportados que gradúan hacia la parte media y superior a capas de arenisca con estratificación imperfecta e intercalaciones de lentes de conglomerado matriz-soportado con algunos derrames intercalados de andesita y basalto. Para una de las andesitas se obtuvo una edad de K-Ar en roca entera de 44.5 ± 0.7 Ma. La unidad superior (Formación Huajintlán) presenta una granulometría notablemente más gruesa representada por conglomerados matriz-soportados con algunos lentes de arenisca conglomerática. Esta unidad subyace en discordancia a la ignimbrita Tilzapotla, para la cual se ha obtenido una edad Ar-Ar en sanidino de 34.3 ± 0.09 Ma. Las capas de ambas unidades tienen buzamientos al oriente y nororiente con echados mayores para la unidad inferior (50-30º). Las facies observadas para ambas unidades revelan que se trata de depósitos de abanico aluvial con facies proximales para la Formación Huajintlán. La sucesión estudiada se localiza inmediatamente al noroeste de una gran estructura dómicaelíptica (50×30 km) que se originó en la etapa de tumefacción, durante la evolución temprana de la caldera Tilzapotla, previa al colapso. La terminación noroccidental del domo converge e interfiere con el cinturón de pliegues y cabalgaduras que forma los altos del sector Iguala-Cacahuamilpa cerca de Taxco. En el área de estudio, el contorno del domo presenta una inflexión local definida por un cambio en la dirección del echado de las capas de la formación Morelos y la base de la Formación Tepetlapa de norte a este. La ligera discordancia angular entre la Formación Tepetlapa y las unidades subyacente indican una primera etapa de inclinación hacia el noreste probablemente originada por el levantamiento en el área de Taxco que acompaño el emplazamiento de magmas silícicos (ca. 38 Ma). Las facies proximales de la Formación Huanjintlán y la edad (35.1 ± 0.4 Ma) de la Toba Piedras Altas indican que esta formación resultó de un rejuvenecimiento del área fuente provocado por la tumefacción en el área más cercana de la caldera Tilzapotla. Esto se confirma por los echados mayores de la Formación Tepetlapa (~50º) en las capas próximas a la estructura dómica. La edad de una de las andesitas intercaladas (44.5 Ma) en la unidad inferior es indicativa de una edad eocénica para el inicio de la acumulación del Grupo Balsas en esta áre

Registration of ‘CI0947bmr’ Sorghum

The sorghum [Sorghum bicolor (L.) Moench] cultivar CI0947bmr (Reg. No. CV-137, PI 672153) was jointly developed and released by the Centro Nacional de Tecnología Agropecuaria y Forestal (CENTA) research program in El Salvador and the Texas A&M Agrilife Research sorghum breeding program in 2013. CI0947bmr is a brown midrib (bmr), dual-purpose sorghum selected for productivity in Central American environments. CI0947bmr was developed from a pedigree breeding program, and it was derived from a BC1F2 population of the pedigree B03292bmr/Tortillero//Tortillero. All generation advancement and selection were completed in San Andres, El Salvador. To confirm performance of the line, CI0947bmr was evaluated in replicated yield trials in 10 Central American environments ranging from Panama to Guatemala in 2010 and 2011. Compared with Sureno (a non-bmr dual-purpose sorghum cultivar grown in the region), CI0947bmr is similar in maturity, dry biomass yield, grain yield, and composition, with lower concentration of lignin and higher in vitro dry matter digestibility and total digestible nutrients. Given these characteristics, CI0947bmr can be used for forage production (grazing and silage) or for grain production with the post-harvest plant residue suitable as forage. In addition, producers can save seed for replanting. This cultivar is designed to provide small livestock producers and dairies in Central America with access to sorghum forage with improved forage quality without sacrificing dry matter yield, grain yield, or grain quality