Ecoteología

Bogot

Water splitting behavior of copper-cerium oxide nanorods and nanocubes using hydrazine as a scavenging agent

"A one-step microwave synthesis using neither a template surfactant nor strong molar NaOH concentrations is reported. Well shaped nanorod and nanocube CeO2 structures were achieved in 0.5 and 4 h at a maximum irradiation of 200 W, respectively. Both nanostructures grew through different processes, they are dependent on the irradiation conditions, time and temperature. The photocatalytic water splitting evaluation of cerium oxide nanostructures was carried out using water contaminated with hydrazine and the surface “in-situ” functionalization of Cu0 nanoparticles (CuNPs) on the surface, achieving 753 μmol/h g of hydrogen generation. During the photocatalytic process, the “in-situ” reduction reaction (CuO → Cu0) occurring on the CeO2 surface promotes the electron transfer process due to the copper work function.

The Llamas de Cabrera gold district, a new discovery in the Variscan basement of northwest Spain: A fluid inclusion and stable isotope study

[EN] The northwest of the Iberian Massif is well known to host numerous gold mineralizations which were exploited during Roman times. This study presents a multidisciplinary approach leading to the mineralogical, fluid inclusions, and geochemical characterization of the recently rediscovered Roman gold district of Llamas de Cabrera. Gold occurs in extensional quartz veins hosted in the upper layers of the Lower to Middle Ordovician Armorican quartzite and occasionally in the overlaying Middle Ordovician slates from Luarca Formation. The veins are characterized by multistage ore deposition developed along three hydrothermal stages: As–Fe (I), As–Fe (II), and Au–Zn–Cu–Pb, followed by late supergene alteration processes. The fluid inclusion study undertaken on mineralized quartz revealed the presence of three types of fluids: (1) CO2–(CH4) fluid inclusions, (2) aqueous-carbonic fluid inclusions dominated by CO2 and subordinate CH4 related to quartz–arsenopyrite–pyrite deposition, and (3) aqueous fluid inclusions related to the Au-sulfide deposition. In conjunction with arsenopyrite geothermometry and fluid-inclusion data an attempt was made to determine the P–T conditions of ore formation. Changes occurred in the P–T conditions fromarsenopyrite and pyrite deposition in quartz veins from aqueous-carbonic fluids at 300–390 °C and 200–220 MPa towards 180–310 °C and b200 MPa at the stage of gold from aqueous fluids.Mixing of two aqueous fluids of relatively contrasted salinity were favorable factors for decreasing gold solubility and could allow gold deposition. The δ34S values are similar for the two As–Fe stages, +8.0‰ to +16.3‰ and +9.0‰ to +19.5‰ respectively, and for the post-S1 pyrites from siliciclastic Luarca Formation suggesting a comparable sulfur source. Combining calculated δ18O values of fluids of+6.7 to+9.4‰with fluid inclusion data indicates that fluids of unknown origin are largely equilibrated withmetamorphic lithologies at medium–high temperatures. The ascent of some late Variscan magmatic bodies, not exposed at the present day erosion level, provides the heat source for convective water circulation. Gold quartz veins from Llamas de Cabrera display similar features and processes to related deposits of similar type elsewhere in the Variscan belt of western Europe (northwest and central/western Iberia, French Massif Central, BohemianMassif). However Llamas de Cabrera shows certain differences, such as the non-appearance of igneous rocks in the area and the absence of Sb-rich minerals compared to some Variscan Sb–Au deposits, including northern, central, and western Iberia. This last could probably be due to a greater depth of formation for the As–Au veins in comparison to Sb–Au veins.SIThis research has been funded through the research project 2005/ 103, Diputación Provincial de León

PS-b-P4VP block copolymer micelles as a soft template to grow openly porous nickel films for alkaline hydrogen evolution

Highly porous Ni films have been potentiostatically synthesised by micelle-assisted electrodeposition using custom-made PS-b-P4VP block copolymer micelles as a soft template. Two PS-b-P4VP block copolymers with PS/P4VP block ratios of 1:1 and 1:4 were used for the micelle-assisted electrodeposition, resulting in Ni films with large pores of diameters varying from 25 to 600 nm (1:1), and from 10 to 230 nm (1:4). As a result of the interconnected porosity, and hence the drastic increase of the surface-to-volume ratio, the electrocatalytic performance at hydrogen evolution reaction (HER) in alkaline media is significantly improved in comparison to a dense Ni film, and—more importantly—even in comparison to a highly mesoporous Ni film with monodisperse 10 nm wide pores. Most remarkably, it is discovered that the openly porous Ni electrocatalysts not only lead to a simple increase in HER current density, but also to a lower overpotential and a better long-term performance. While the bulk of the films is metallic, Ni(OH)2 is formed on the surfaces of all Ni films during HER. This effect leads to an initial decrease of the catalytic activity, but provides excellent stability in alkaline media. The presented synthesis process for pure Ni may be readily adopted to any other electroplatable metals and alloysThis work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101058076 and the Marie Skłodowska-Curie grant agreement No 764977. Additional funding was obtained from the Generalitat de Catalunya under project 2017-SGR-292 and the Spanish Government under PID2019–108794 GB-I00, PID2020–116844RB-C21, and associated FEDER Project. KE acknowledges the Spanish Ministerio de Uni- versidades for a Margarita Salas fellowship, financed by the European Union – NextGenerationEU. AGC acknowledges financial support from the Spanish Ministry of Science through the “Severo Ochoa” Programme for Centres of Excellence (FUNFUTURE, 2020–2023)Postprint (published version

Evaluación del método biointensivo como manejo sustentable del recurso suelo en la Comunidad Los Lavanderos – Ambuquí

La comunidad Los Lavanderos de la parroquia Ambuquí, cantón Ibarra, en los últimos años ha sufrido una acelerada pérdida de suelo debido a factores naturales, al uso de sistemas agrícolas inadecuados, por la baja conciencia ambiental y pocas gestiones para la conservación de los recursos naturales. Muchas familias de la zona perciben a la agricultura como una actividad improductiva y de segunda prioridad

Automated Design of Salient Object Detection Algorithms with Brain Programming

Despite recent improvements in computer vision, artificial visual systems' design is still daunting since an explanation of visual computing algorithms remains elusive. Salient object detection is one problem that is still open due to the difficulty of understanding the brain's inner workings. Progress on this research area follows the traditional path of hand-made designs using neuroscience knowledge. In recent years two different approaches based on genetic programming appear to enhance their technique. One follows the idea of combining previous hand-made methods through genetic programming and fuzzy logic. The other approach consists of improving the inner computational structures of basic hand-made models through artificial evolution. This research work proposes expanding the artificial dorsal stream using a recent proposal to solve salient object detection problems. This approach uses the benefits of the two main aspects of this research area: fixation prediction and detection of salient objects. We decided to apply the fusion of visual saliency and image segmentation algorithms as a template. The proposed methodology discovers several critical structures in the template through artificial evolution. We present results on a benchmark designed by experts with outstanding results in comparison with the state-of-the-art.Comment: 35 pages, 5 figure

Phosphomannosylation and the functional analysis of the extended Candida albicans MNN4-like gene family

We thank Luz A. López-Ramírez (Universidad de Guanajuato) for technical assistance. This work was supported by Consejo Nacional de Ciencia y Tecnología (ref. CB2011/166860; PDCPN2014-247109, and FC 2015-02-834), Universidad de Guanajuato (ref. 000025/11; 0087/13; ref. 1025/2016; Convocatoria Institucional para Fortalecer la Excelencia Académica 2015; CIFOREA 89/2016), Programa de Mejoramiento de Profesorado (ref. UGTO-PTC-261), and Red Temática Glicociencia en Salud (CONACYT-México). NG acknowledges the Wellcome Trust (086827, 075470, 101873, and 200208) and MRC Centre for Medical Mycology for funding (N006364/1). KJ was supported by a research visitor grant to Aberdeen from China Scholarship Council (CSC No. 201406055024). The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmicb.2017.02156/full#supplementary-materialPeer reviewedPublisher PD

Hidradenitis Supurativa Glútea y Perineal: diagnóstico y manejo terapéutico

La hidradenitis supurativa (HS) es una enfermedad inflamatoria crónica de la piel que afecta a las glándulas sudoríparas apocrinas y causa nódulos inflamatorios, abscesos y fistulas dolorosas en áreas como las axilas, la ingle y los glúteos. Su impacto en la calidad de vida de los pacientes es significativo. La HS afecta al 1-4% de la población mundial y se asocia con factores como el sobrepeso, el tabaquismo y antecedentes familiares. Su patogenia es compleja, involucrando inflamación y disfunción inmunológica. Su diagnóstico y tratamiento son desafiantes, especialmente en casos graves. El diagnóstico se basa en la presentación clínica, que a menudo se confunde con otras afecciones cutáneas. Se clasifica en etapas de Hurley según la gravedad. El tratamiento se centra en controlar los síntomas y prevenir recurrencias. Incluye educación del paciente, tratamiento médico y cirugía. La elección de la terapia antibiótica depende de la severidad y las cepas bacterianas presentes. Para casos graves, se investigan terapias biológicas. La cirugía, como la escisión simple o con injertos de piel, es efectiva en el control de la enfermedad. Presentamos un caso clínico de un paciente con HS, revisamos la epidemiología, etiopatogenia y su diagnóstico acompañado de las opciones terapéuticas existente

Aplicación de un método para cuantificar la pérdida de alimentos en pequeños productores de berries y hortalizas en la región del Maule

40 P.El presente estudio tiene como objetivo cuantificar las pérdidas de alimentos en una muestra de 182 productores AFC de berries y hortalizas entre las regiones del Maule y Ñuble, los cuales se caracterizaron en cuanto a su superficie predial, gestión agrícola, situación socioeconómica y sistema productivo. La cuantificación de las pérdidas se llevó a cabo mediante un método propuesto por la Oficina de Estudios y Políticas Agrarias, el cual evalúa las mermas en la producción agrícola en cuanto a la masa (en kg) para posteriormente transformarla a otras unidades de medida como calorías (en kcal), lo que facilita el acceso a los datos y su medición, siendo además uno de los métodos más fáciles de comparar en todos los niveles de análisis. Para la medición se examinaron las pérdidas de alimentos percibidas por los encuestados durante las etapas de cosecha, envasado o embalaje, transporte y comercialización. La hipótesis propuesta busca analizar si la información entregada por el extensionista reduciría la pérdida de alimentos en la Agricultura Familiar Campesina, para lo cual se establecieron 3 indicadores de entrega de información de las PDA (capacitación, información o desconocimiento). Posteriormente para efecto de la investigación se realizó un análisis de varianza con arreglo factorial univariado para las variables sistema productivo y efecto del extensionista sobre las pérdidas de alimento usando el programa IBM SPSS. Los resultados encontrados sostienen una diferencia significativa en cuanto al sistema productivo, siendo los productores de hortalizas quienes obtuvieron mayores pérdidas de alimentos respecto a productores de berries y mixtos. Por su parte la información entregada por los extensionistas influye en la disminución de las pérdidas de alimentos, pero las diferencias no son significativas

Reporte de caso y revisión breve Paciente con un caso poco frecuente de hta: pseudohipoaldosteronismo tipo 2 o síndrome de Gordon

Describimos el caso de una paciente con diagnóstico de hipertensión arterial (HTA) desde los 14 años de edad con frecuentes hospitalizaciones por crisis hipertensivas que no se lograban controlar con dosis crecientes de antihipertensivos. Se le realizaron múltiples estudios para HTA secundaria pero lo único anormal fue la presencia de hipercaliemia y acidosis metabólica. Con estos hallazgos se hizo la impresión diagnóstica de pseudohipoaldosteronismo tipo 2 o síndrome de Gordon y se instauró tratamiento con hidroclorotiazida en dosis crecientes con lo cual se lograron estabilizar las cifras tensionales y mejorar la hipercaliemia. Abstract We describe the case of a patient diagnosed with hypertension at age 14 with multiple hospitalizations for hypertensive crisis. Despite increasing doses of antihypertensive drugs, her blood pressure was not controlled. Attempts were made to rule out secondary hypertension, but to no avail, except for the presence of hyperkalemia and metabolic acidosis. With these results, the diagnostic impression was of Type 2 pseudohypoaldosteronism or Gordon’s syndrome. The patient was treated with thiazides at increasing doses, which succeeded in stabilizing her blood pressure and improving hyperkalemia