1,409 research outputs found

    Adsorption of emerging pollutants on lignin-based activated carbon: Analysis of adsorption mechanism via characterization, kinetics and equilibrium studies

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    Lignin has been employed as a precursor to synthesize activated carbons with the aim of lignin-biomass revalorization. The properties of these activated carbons were compared, and the best adsorbent was employed to remove two emerging pollutants from water, acetaminophen and acetamiprid. The adsorption mechanisms of pharmaceutical and pesticide compounds were analyzed, modeled and interpreted via statistical physics models. In particular, adsorption kinetics and isotherms of acetaminophen and acetamiprid at temperatures between 20 and 60 ◦C were quantified experimentally. Equilibrium data were fitted to different statistical physics-based isotherm models to establish the corresponding adsorption mechanism. A double layer adsorption model with one type of functional group was the best to correlate and explain the removal of these organic molecules. Steric parameters for the adsorption of these organic compounds were also calculated thus determining that their adsorption was multi-molecular. At tested operating conditions, acetaminophen adsorption was endothermic, while acetamiprid removal was exothermic. Physical adsorption forces were expected to be responsible for the removal of both compounds. This study reports new insights on the adsorption mechanisms of relevant emerging pollutants commonly found in water worldwid

    Proyectos región para la conservación de suelos de ladera

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    La zona de ladera del departamento del Valle del Cauca está conformado por las cordilleras occidental y central con sus estribaciones, faldas y laderas. Los suelos se han clasificado agroecológicamente en las clases ii y iii y presentan algún tipo de deterioro por lo cual deben ser manejados con prácticas de conservación

    Control antimicrobiano integral: estrategia contra las infecciones nosocomiales en veterinaria

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    El desarrollo de mecanismos de prevención y control frente a los microorganismos nosocomiales son esfuerzos importantes para desarrollar en los hospitales tanto humanos como veterinarios. Entre las estrategias encaminadas a reducir la flora microbiana patógena y la resistencia a múltiples fármacos en los hospitales, se encuentran la reducción de la diseminación de microorganismos por parte del personal a los animales, evitar la adquisición de microorganismos de equipos hospitalarios y de infraestructura, la realización de programas permanentes de limpieza, desinfección y esterilización y un uso racional de los antimicrobianos. Elpresente artículo describe los principios fundamentales del control microbiológico hospitalario, basado en el contexto médico veterinario en Colombia

    Rapid Intensity Decrease During the Second Half of the First Millennium BCE in Central Asia and Global Implications

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    Recent paleomagnetic studies have shown that important short-lived intensity fluctuations occurred during the first millennium BCE. However, the knowledge of the spatial and temporal extension of these features is still limited by the scarce availability of robust data. In this study we focus on the study of the intensity decrease that took place in Central Asia during the second half of the 1st millennium BCE after the high intensities that characterized the Levantine Iron Age Anomaly. Since previous archeointensities available for this period and region were obtained without accomplishing modern standards of quality, we present here new archeointensities that are derived from classical Thellier and Thellier experiments, including partial thermoremanent magnetization (pTRM) checks, thermoremanent magnetization (TRM) anisotropy and cooling rate corrections at the specimen level. The new 51 archeointensities, together with previous archeointensities, have been used to present a new local paleosecular variation curve for Central Asia. The results confirm the existence of an important geomagnetic field intensity decrease in South Uzbekistan from the 4th century BCE to the end of the 1st century BCE associated with rates of changes up to −15 μT/century. A critical analysis of the archeointensity global database indicates that this feature was present at continental scale, from Western Europe to Central Asia. However, this trend is not identified in other regions such as Japan or Mexico. Finally, the comparison with the dipole moment derived from recent global geomagnetic field reconstructions suggests a strong influence of non-dipolar sources upon this continental intensity feature.Financial support was given by the Spanish Ministry of Science and Innovation thorough the projects CERAC (HAR2016-75133-C3-1-P), CONCERAC (HAR2016-75133-C3-3-P), SPYKE (CGL2017-87015-P), SÚMATE (PID2020-113316GB-I00) and PULSES 5.K (PID2020-117105RB-I00). R. Bonilla-Alba thanks the FPI fellowship (PRE2018-085949) associated with the SPYKE project. This study has been also funded by the Ramón y Cajal program (contracts of M. Gómez-Paccard and V. Martínez-Ferreras, refs. RYC-2013-14405 and RYC-2014-15789). The authors wish to acknowledge the professional support of the CSIC Interdisciplinary Thematic Platform Open Heritage: Research and Society (PTI-PAIS). E. Beamud thanks the Geomodels Research Institute (UB) and the Grup de Geodinàmica i Anàlisi de Conques-2017SGR596 (Generalitat de Catalunya). A. Palencia-Ortas thanks the PTA contract of the Spanish Ministry of Science and Innovation

    Rapid Intensity Decrease During the Second Half of the First Millennium BCE in Central Asia and Global Implications

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    Recent paleomagnetic studies have shown that important short-lived intensity fluctuations occurred during the first millennium BCE. However, the knowledge of the spatial and temporal extension of these features is still limited by the scarce availability of robust data. In this study we focus on the study of the intensity decrease that took place in Central Asia during the second half of the 1st millennium BCE after the high intensities that characterized the Levantine Iron Age Anomaly. Since previous archeointensities available for this period and region were obtained without accomplishing modern standards of quality, we present here new archeointensities that are derived from classical Thellier and Thellier experiments, including partial thermoremanent magnetization (pTRM) checks, thermoremanent magnetization (TRM) anisotropy and cooling rate corrections at the specimen level. The new 51 archeointensities, together with previous archeointensities, have been used to present a new local paleosecular variation curve for Central Asia. The results confirm the existence of an important geomagnetic field intensity decrease in South Uzbekistan from the 4th century BCE to the end of the 1st century BCE associated with rates of changes up to −15 μT/century. A critical analysis of the archeointensity global database indicates that this feature was present at continental scale, from Western Europe to Central Asia. However, this trend is not identified in other regions such as Japan or Mexico. Finally, the comparison with the dipole moment derived from recent global geomagnetic field reconstructions suggests a strong influence of non-dipolar sources upon this continental intensity feature

    Mitochondrial echoes of first settlement and genetic continuity in El Salvador

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    Background: From Paleo-Indian times to recent historical episodes, the Mesoamerican isthmus played an important role in the distribution and patterns of variability all around the double American continent. However, the amount of genetic information currently available on Central American continental populations is very scarce. In order to shed light on the role of Mesoamerica in the peopling of the New World, the present study focuses on the analysis of the mtDNA variation in a population sample from El Salvador. Methodology/Principal Findings: We have carried out DNA sequencing of the entire control region of the mitochondrial DNA (mtDNA) genome in 90 individuals from El Salvador. We have also compiled more than 3,985 control region profiles from the public domain and the literature in order to carry out inter-population comparisons. The results reveal a predominant Native American component in this region: by far, the most prevalent mtDNA haplogroup in this country (at ~90%) is A2, in contrast with other North, Meso- and South American populations. Haplogroup A2 shows a star-like phylogeny and is very diverse with a substantial proportion of mtDNAs (45%; sequence range 16090–16365) still unobserved in other American populations. Two different Bayesian approaches used to estimate admixture proportions in El Salvador shows that the majority of the mtDNAs observed come from North America. A preliminary founder analysis indicates that the settlement of El Salvador occurred about 13,400±5,200 Y.B.P.. The founder age of A2 in El Salvador is close to the overall age of A2 in America, which suggests that the colonization of this region occurred within a few thousand years of the initial expansion into the Americas. Conclusions/Significance: As a whole, the results are compatible with the hypothesis that today's A2 variability in El Salvador represents to a large extent the indigenous component of the region. Concordant with this hypothesis is also the observation of a very limited contribution from European and African women (~5%). This implies that the Atlantic slave trade had a very small demographic impact in El Salvador in contrast to its transformation of the gene pool in neighbouring populations from the Caribbean facade

    Acute effects of dynamic Tape® application on vertical jump performance : A case report

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    Actualmente, no existe un consenso sobre los beneficios de los diferentes tipos de cintas neuromusculares sobre el rendimiento muscular. A diferencia del vendaje neuromuscular y las cintas rígidas, el Dynamic Tape® tiene una composición y propiedades diferentes con efectos desconocidos sobre el rendimiento. El objetivo de este estudio fue reportar los efectos agudos del tape dinámico® sobre el rendimiento del salto vertical. Materiales y métodos: Utilizando una metodología test-retest, se realizó un estudio de caso con dos mujeres de 21 años, saludables y físicamente activas. Se evaluó el tiempo de vuelo, la altura del salto y la potencia muscular a través de salto desde sentadilla y salto con contra movimiento en plataforma de contacto, antes y después de la aplicación del tape dinámico® en cuádriceps y en gastrocnemios. Resultados: Se encontraron mejoras en el salto desde sentadilla de hasta 10.8% en el tiempo de vuelo, 22.6% en la altura del salto y 8.9% en la potencia muscular después de la aplicación del tape dinámico®. Conclusiones: Este estudio preliminar y exploratorio mostró que la utilización del tape dinámico® podría mejorar el rendimiento del salto vertical; sin embargo, se necesitan más investigaciones sobre este tipo de vendaje.Different types of neuromuscular tapes have led to no consensus about its benefits on muscle performance. Unlike kinesiology and rigid tapes, Dynamic Tape® has different composition and properties with unknown effects on performance. The aim of this exploratory-type case study was to report the acute effects of dynamic tape® application on vertical jump performance. Material and methods: Using a test-retest methodology, a case study was carried out in two 21-year-old, healthy and physically active women. Flight time, jump height and muscle power were evaluated by squat jump and countermovement jump tests using a contact mat, before and after the application of dynamic tape® on quadriceps and gastrocnemius muscles. Single and double taping were also used in different combinations. Results: Improvements of up to 10.8% on flight time, 22.6% on jump height and 8.9% on muscle power were observed for squat jump after the application of dynamic tape®. Conclusions: This preliminary and exploratory case study showed that using dynamic tape® might improve vertical jump performance; however, further research is necessary in this relatively novel type of tape
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