Comportamiento del SDS localizado en la región interfacial del sistema agua/n-octano. Un estudio usando dinámica molecular

En este trabajo, usando dinámica molecular se determinaron las propiedades interfaciales y el comportamiento del Dodecil Sulfato de Sodio (SDS) ubicado en la región interfacial de los sistemas vacío/agua y agua/n-octano. La tensión interfacial fue estimada con el modelo propuesto por Kirkwood y Buff [23]. A su vez, los espesores de película interfacial fueron determinados usando los criterios 10-90 y 90-90. Además, el área por molécula fue estimado con la variación de la presión superficial en función de la concentración del surfactante. En los sistemas vacío/SDS/agua, el área por molécula del SDS fue obtenida con dos procedimientos diferentes. Los valores fueron 53.3 Å2 y 54.3 Å2, respectivamente. Para los sistemas agua/n-octano y agua/SDS/n-octano, los espesores de película interfacial aumentan en función del número de moléculas de surfactantes presentes en la región interfacial. Los resultados obtenidos son consistentes con datos medidos por experimentación

Nivel de estrategias de enseñanza del pensamiento crítico en una Institución Educativa de Huancayo 2021

La finalidad de la presente investigación es conocer a profundidad los fundamentos científicos de las estrategias del pensamiento crítico que usan los docentes en sus prácticas pedagógicas en el marco de la educación peruana actual (s. XXI), siendo tan necesarios para un aprendizaje por competencias. El método que se usará en la presente investigación es el analítico puesto que, se realizará un diagnóstico de problemas para tener un conocimiento más profundo de la realidad y a partir de ello generar hipótesis que permitan resolverlos. La investigación ha llevado a concluir que, es de suma importancia desarrollar y aplicar estrategias para el desarrollo del pensamiento crítico en la labor educativa, porque promueven y desarrollan la criticidad en los estudiantes, mejorando la calidad tanto de la enseñanza como del aprendizaje, formando seres humanos conscientes y críticos de la realidad que buscan forjar una sociedad más justa, humana y fraterna. Palabra clave: estrategias, pensamiento crítico y aprendizaje.Tesi

Exploring the effect of the O -(1-heptylnonyl) benzene sulfonate surfactant on the nature of the linear hydrocarbons/water interface by means of an atomistic molecular dynamics simulation

Using molecular dynamics simulations a systematic study of the binding energy per cross sectional area for the water/n-alkane (hexane, octane, decane, dodecane and tetradecane) interfaces was performed. The effect of the Sodium p-(1-heptylnonyl) benzene sulfonate surfactant, on the adhesion forces of the water/n-hydrocarbon (decane, undecane, dodecane, and tetradecane) interfaces was studied. Scanning of the binding energy per area against n-alkanes shows that the magnitude of this parameter for the surfactant tail-alkane interactions at the interface systematically increases with the chain length of the alkane, whereas it shows a maximum at undecane for the water-surfactant head interactions at the interface. This maximum of head adhesion forces thus agrees with the reported minimum value of the interfacial tension at undecane for the p-(1-heptylnonyl) benzene sulfonate, suggests that for the water/alkane interface it is this trend in surfactant head adhesion at the interface that defines that interfacial tension minimum value

Implementation of a Hybrid Educational Program between the Model of Personal and Social Responsibility (TPSR) and the Teaching Games for Understanding (TGfU) in Physical Education and Its Effects on Health: An Approach Based on Mixed Methods

The present study investigates the effect of an educational program hybridized between the Model of Personal and Social Responsibility (TPSR) and the Teaching Games for Understanding (TGfU) in physical education classes on the health and psychosocial variables of students, as well as knowing the advantages and disadvantages of its implementation by teachers. The applied program lasted 11 weeks in two Secondary Education centers with a total of four teachers (two in the experimental group and two in the control group) and 99 students (55 from the control group and 44 from the experimental group). We use research methodology Mixed Methods with a quasi-experimental design, where students completed a questionnaire before and after the educational program and teachers were interviewed at the end of the intervention. The results of the questionnaires indicate significant improvements in the experimental group over time in terms of the intention to be physically active, as well as in autonomous motivation, the self-determination index, the index of psychological mediators, personal and social responsibility, and enjoyment. Moreover, the interviews show positive opinions regarding the organizational capacity of the session using this methodology and the interest of teachers in continuing to apply it in the future, as well as the need for initial and ongoing training for proper implementation. In conclusion, the hybridization between the TPSR and TGfU model is presented as an effective alternative to be applied in the educational context with the aim of improving young peoples’ intention to be physically active and psychological variables, such as motivation, responsibility, and enjoyment, in physical education classes

Distribución del 1-butanol y 2-butanol en los sistemas agua/n-octano y agua/Dodecil ´Sulfato de Sodio (SDS)/n-octano usando dinámica molecular. Parte II. Uso de las herramientas gmx-density y gmx-densmap

En este trabajo, la distribución de las moléculas de 1-butanol y 2-butanol en los sistemas agua/n-octano y agua/SDS/n-octano fue determinada usando las herramientas gmx-density y gmx-densmap del programa gromacs con la finalidad de complementar a nivel computacional el comportamiento experimental estos co-surfactantes cuando están localizados en la región interfacial de estos sistemas. Los modelos de energía potencial GROMOS53A6 y SPC fueron utilizados para describir a las moléculas de 1-butanol, 2-butanol, SDS y agua, respectivamente. Estos modelos fueron capaces de predecir las propiedades interfaciales del sistema agua/n-octano y el área por molécula del Dodecil Sulfato de Sodio en la interfaz agua/n-octano de forma consistente. Finalmente, los perfiles y mapas de densidad demuestran que las moléculas de alcohol y SDS coexisten en la región interfacial del sistema agua/n-octano favoreciendo la estabilidad de la monocapa de surfactante y la película interfacial

La terminología como elemento de la Gestión del conocimiento en las organizaciones: Las empresas públicas de Medellín – EE.PP.M.

Upon completion of a research project on the degree to which knowledge management is utilized in the service industries of Medellín, it was possible to establish a knowledge management model based on these tools: organizational learning, documentation, standards, terminology, and technology management. The special emphasis in this article is on terminology and its application as a facilitating agent in information management processes in one of the companies that serves as a test site for our research: the Medellín Public Works. This part of the article is preceded by an introduction to knowledge management and its corresponding application in organizations, as well as the articulation of its processes with the terminology. It becomes clear in the process that the applications described are based in the experience related by the managers who are responsible for these processes in the Medellín Public Works and who, in the development of this article, interacted with the research team that worked with terminology as a tool

An Unprecedented Aggregation of Whale Sharks, Rhincodon typus, in Mexican Coastal Waters of the Caribbean Sea

Whale sharks, Rhincodon typus, are often perceived as solitary behemoths that live and feed in the open ocean. To the contrary, evidence is accumulating that they are gregarious and form seasonal aggregations in some coastal waters. One such aggregation occurs annually north of Cabo Catoche, off Isla Holbox on the Yucatán Peninsula of Mexico. Here we report a second, much denser aggregation of whale sharks (dubbed “the Afuera”) that occurs east of the tip of the Yucatán Peninsula in the Caribbean Sea. The 2009 Afuera event comprised the largest aggregation of whale sharks ever reported, with up to 420 whale sharks observed in a single aerial survey, all gathered in an elliptical patch of ocean approximately 18 km2. Plankton studies indicated that the sharks were feeding on dense homogenous patches of fish eggs, which DNA barcoding analysis identified as belonging to little tunny, Euthynnus alletteratus. This contrasts with the annual Cabo Catoche aggregation nearby, where prey consists mostly of copepods and sergestid shrimp. Increased sightings at the Afuera coincide with decreased sightings at Cabo Catoche, and both groups have the same sex ratio, implying that the same animals are likely involved in both aggregations; tagging data support this idea. With two whale shark aggregation areas, high coastal productivity and a previously-unknown scombrid spawning ground, the northeastern Yucatán marine region is a critical habitat that deserves more concerted conservation efforts

Influence of Environmental Pollution and Living Conditions on Parasite Transmission among Indigenous Ecuadorians

The purpose of this study was to evaluate the influence of environmental pollution and the living conditions of indigenous Ecuadorians on the transmission of enteroparasites in an Andean agricultural area located at high altitude. Environmental pollution was recorded after observation in each community. The parasites were identified by microscopic sediment analysis using physiological saline solution from macerated arthropods, washed vegetables, and human stools, utilizing four coproparasitological techniques (direct examination, Kato-Katz, ether concentration, and Ziehl-Neelsen). The results show that the inadequate disposal of human and animal excreta that contaminate soil and water, incorrect food hygiene, inadequate sanitary infrastructure in houses, a lack of animal veterinary care, and rodent proliferation are important reservoirs of zoonotic parasites. The use of excrement as fertilizer increases the number of flies, which act as mechanical vectors, and vegetables grown in areas with disperse infective parasitic forms act as vehicles that are marketed at the local, regional, and international levels. These analyses verify contamination levels of 52.7% in mechanical vectors, 70.6% in vegetables, and 98.2% in human stools. The agricultural communities analyzed maintained poor hygienic-sanitary and environmental conditions, which had a significant influence on the transmission of enteroparasites that affect human health

CARACTERIZACIÓN GEOQUÍMICA DE LOS SEDIMENTOS SUPERFICIALES DEL CAÑO MÁNAMO, DELTA DEL RÍO ORINOCO, VENEZUELA

Se realizó la caracterización geoquímica sedimentos superficiales de caño Mánamo en el delta del río Orinoco. Las muestras de sedimento analizadas corresponden a 7 estaciones establecidas a todo lo largo del caño, muestreándose en cada estación ambas márgenes y la zona central del río. El análisis textural de los sedimentos se llevó a cabo mediante el método sedimentológico de Bouyoucos, la materia orgánica por termogravimetría y el carbono orgánico mediante digestión húmeda. Los sedimentos pulverizados fueron sometidos a fraccionamiento con ácidos débiles y fuertes para separar los metales asociados a la fracción biodisponible (extraídos con ácido acético al 10%) y residuales (extraídos con mezcla de ácido nítrico y peróxido de hidrógeno). La cuantificación de los metales se realizó por espectrometría de emisión atómica con plasma acoplado inductivamente (ICP-EOS). La concentración de aceites y grasas e hidrocarburos se determinó por el métodoCARIPOL y el método 8440 de la US EPA. Los sedimentos superficiales del caño Mánamo se clasifican como del tipo arenoso y areno limosos, con un promedio de 65,66% de arena, 21,84% de limo y 11,93% de arcilla. El contenido materia orgánica fluctuó entre 0,12 a 14,92% y un valor promedio de 2,54%. La máxima concentración de materia orgánica se determinó en una de las márgenes del sector de Winamorena. El resto de las estaciones presentaron valores inferiores al 5%. Las concentraciones de carbonatos variaron 0,14-2,51%, con un promedio de 0,62%. Las mayores concentraciones de metales se presentan en la fracción residual (Fr) así como en los oxihidróxidos de hierro y manganeso (F3). En el caso de Mn y el Cu se detectaron niveles de metales asociados a las fracciones intercambiables (F1) y carbonatos (F2). No se detectaron los metales Cd, Ni, Co y As en ninguna de las estaciones ni fracciones geoquímicas de los sedimentos superficiales. Se observa una tendencia general donde las mayores concentraciones de aceite y grasas e hidrocarburos alifáticos se presentan hacia la margen con menor influencia delflujo del caño donde se presentan menores contenidos de limos y arcillas. La textura de los sedimentos así como el contenidode metales y materia orgánica están condicionados por la hidrodinámica del caño Mánamo y la interacción con la cuña salina en el tramo cercano a su desembocadura. Existe una fuerte asociación entre los metales y la materia orgánica con las fracciones limosas y arcillosas de los sedimentos.Palabras clave: Calidad de sedimentos, fraccionamiento geoquímico, caño MánamoABSTRACT: The geochemical characterization of surface sediments of caño Mánamo in the delta of the Orinoco River,was performed. The sediment samples analyzed correspond to 7 stations established throughout the pipe, both being sampledat each station and the central banks of the river. Textural analysis of sediment was conducted by the sedimentological method of Bouyoucos, organic matter by thermogravimetry and organic carbon by wet digestion. Powdered sediment underwentfractionation with weak and strong acid to remove metals associated to the bioavailable fraction (extracted with 10% aceticacid) and residual (extracted with mixture of nitric acid and hydrogen peroxide). The quantification of metals was performedby atomic emission spectrometry with inductively coupled plasma (ICP-EOS). The concentration of oils and fats andhydrocarbons were determined by the methods of CARIPOL and 8440 U.S. EPA. The surface sediments of caño Mánamo areclassified as sandy and sandy silt, with an average of 65.66% sand, 21.84% silt and 11.93% clay. The organic matter contentranged from 0.12 to 14.92% and an average value of 2.54%. The highest concentration of organic matter was found in oneof the margins Winamorena sector. The remaining stations had values lower than 5%. Carbonate concentrations ranged from0.14 to 2.51%, with an average of 0.62%. The highest concentrations of metals were identified in the residual fraction (Fr) as well as the iron and manganese oxyhydroxides (F3). In the case of Mn and Cu, metal levels were discovered associated with interchangeable fractions (F1) and carbonates (F2). We detected metals Cd, Ni, Co and As in none of the stations orgeochemical fractions of the surface sediments. There is a general trend where the highest concentrations of oil and grease and aliphatic hydrocarbons occur toward the lower margin of the river flow influence which have lower content of silt and clay.The texture of the sediments and metal content and organic matter are conditioned by the hydrodynamics of caño Mánamoand interaction with the salt wedge in the stretch near its mouth. There is a strong association between metals and organicmatter silt and clay fractions of sediments.Key words: Quality of sediment, geochemical fractionation, caño Mánamo